Clinical Operative III PDF

Contents 1 Additional conservative esthetic procedures 1 2 Anterior composite restoration 67 3 Posterior Resin Composite Restorations 87 Prepared by Chapter 1  Additional Conservative Esthetic Procedures "Beauty is harmony of...

Contents 1 Additional conservative esthetic procedures 1 2 Anterior composite restoration 67 3 Posterior Resin Composite Restorations 87 Prepared by Chapter 1  Additional Conservative Esthetic Procedures "Beauty is harmony of all parts, in whatsoever subject it appears, fitted together with such proportion and connection, that nothing could be added, diminished or altered.... but for the worse." Significant improvements in tooth-colored restorative materials and adhesive techniques have resulted in numerous conservative esthetic treatment possibilities. This chapter presents conservative esthetic procedures in the context of their clinical applications Components affecting esthetics: I- Basal bone. Maxilla and mandibule represents the architecture and foundation on which teeth and all oral muscles will be fixed on, any discrepancy in size or shape of one or both of them will greatly affect the facial esthetics. ❖ Enlarged mandible or deficient maxilla will give appearance of prognathic mandible (class III). Enlarged maxilla or deficient mandible will give appearance of prognathic maxilla (class II). ❖ Correction of basal bones requires orthodontic or orthognathic surgery. 1  II- Musculature ❖ The size, tone and attachment of oral of lips forms the frame of patient smile. ❖ Movement of lips during rest or smile determines how much the smile is attractive as it affects how many teeth will appear? And, how much of teeth will be displayed?. Discrepancies in lips will deteriorate patient esthetics. III- Teeth. Teeth forms the most dominant component of smile so when they are well, the smile will be attractive. Teeth should have proper shape, form, size, alignment, position, arrangement, surface texture, color, and translucency. Scientific esthetic guide line I- Facial analysis II- Dentofacial analysis III-Dental analysis 2  Facial DENTAOFACIAL Dental I. Facial analysis There are three types of faces according to the outline, square, elongated, and mesio-facial face which the most beautiful one. Facial beauty involve proper; alignment symmetry 3  proportion of the face A-Frontal view: There are two facial features which do play a major role in the smile design; The interpupillary line and the lips. Lips are important since they create the boundaries of smile design. The interpupillary line should be parallel to the occlusal plane and perpendicular to the midline of the face. Facial midline. It is the line dividing the face into two equal symmetrical halves, passing through forehead nose and the philtrum at the tip of cupid arch 4  The full face is divided into three equal parts Upper part from hair line to the glabella (or eyebrow) Middle part from glabella to The base of the nose The lower part from the base of the nose to the chin which is subdivided into two parts, the upper lip forms one-third of it and the lower lip and the chin two-thirds of it B-Sagittal view When viewing the face laterally we have two important feature. 1-Esthetic line. It is the line drawn from the tip of the nose to the tip (most prominent part) of chin, the upper lip should be four mm back to it and lower lip should be two mm back to it. 2-Nasolabial angle. 5 The angle between the base of nose and the philtrum of lip and it should be: ❖ -In males 90-95 if it is more give the retrognathic appearance and if less than this range give the prognathic appearance. ❖ -In females 100-105 if it is more give the retrognathic appearance and if less than this range give the prognathic appearance. II- Dentofacial analysis Lips form the frame which encircle the teeth, and both forming the smile components.the ideal dentofacial component should follow the following criteria. 1-Lip line. It is the line of the lower border of upper lip during different movement. During posed smile it have three types: Average lip line in which 75%-1oo% of central incisors and may be 1mm of gingiva appear. Low lip line in which less 75% of central incisors appear. 6  High lip line in which more than 1 mm of gingiva appear and it called gummy smile. 2 Dental midline. The midline refers to the vertical contact interface between two maxillary central incisors. It should be parallel to the midline of the face. The philtrum of the lip is the most accurate anatomical guide posts 7  Maxillary and mandibular midlines do not coincide in 75% of cases. It is not advisable to use the mandibular midline as a reference point. Mismatch between maxillary and mandibular midline does not affect the esthetics because mandibular teeth are not usually visible while smiling. 3-Incisal lengths (incisal edge positions) Is the most important determinant in smile creation because it serves as a reference point to decide the proper tooth proportion and gingival levels. Degree of tooth display: a. 2 mm of incisor edge show at rest b. about 2 mm of gingival show When smiling 8  a b 4-smile line 9 Use phonetics to evaluate the location incisal edge position 10 6. Buccual corridors (Black Esthetics). It is the space between teeth and cheeks during smile and it may be empty and looks black or filled with teeth giving the sense of mouth filled with teeth or in-between. It is affected by: c. -Shape of the arch U shaped arches are better esthetic than V shaped. d. -Tone and size of oral and cheeks muscle. e. -Prominence of canines especially at the disto-facial line angel. f. -Difference of color (value) between canine and premolars. g. -Positioning the buccual surface of upper premolars 7-Zenith point (Pink Esthetics) Are the most apical position of the cervical tooth margin where the gingiva is most scalloped? Usually lies distal to the center of the tooth,with the exception of lateral incisors which is more centerally or in the midline Zenith points is a critical step in alteration of mesial and distal dimensions,and in the closure of diastema 11  incorrect adjustment of the zenith point give the appearance of tilting teeth III-Dental analysis It is concerned with teeth which is back bone of esthetic smile. When analyzing teeth we will look for the following items: I. Shape or form II. Symmetry and proportionality III. Position and alignment IV. Surface texture V. Color VI. Translucency Artistic Elements In conservative esthetic dentistry certain basic artistic elements must be considered to ensure an optimal esthetic result. These elements include the following: I. Shape or form II. Symmetry and proportionality III. Position and alignment 12  IV. Surface texture V. Color VI. Translucency. I. Shape and Form The shape of teeth largely determines their esthetic appearance. To achieve optimal dental esthetics, it is imperative that natural anatomic forms be achieved. Subtle variations in shape and contour produce very different appearances. ▪ Cosmetic Contouring Minor modification of existing tooth contours, sometimes referred to as cosmetic contouring, can effect a significant esthetic change. Reshaping enamel by rounding incisal angles, opening incisal embrasures, and reducing prominent facial line angles can pro- duce a more youthful appearance (Fig. 1). Fig. 1 Cosmetic contouring. A, Anterior teeth before treatment. B, By reshaping teeth, a more youthful appearance is produced ▪ Illusion of Shape Prominent areas of contour on a tooth typically are highlighted with direct illumination, making them more noticeable, whereas areas of depression or diminishing contour are shadowed and less conspicuous. 13 Illusion of narrowness Compared with normal tooth contours (Fig. 2B), a tooth can be made to appear narrower by positioning by the mesiofacial and distofacial line angles closure together. Illusion of width Similarly, greater apparent width can be achieved by positioning the line angles and developmental depressions further apart (Fig. 2C). A B C Normal Narrowing Widening Fig.2 Creating illusions of width. A, Normal width. B, A tooth can be made to appear narrower by positioning mesial and distal line angles closer together and by approximating developmental depressions. C, Greater apparent width is achieved by positioning line angles and developmental depressions farther apart. Illusion of height 1. Compared with normal tooth contours (Fig. 3 A), a tooth can be made to appear shorter by positioning the gingival height of contour further incisally (Fig. 3B). 2. Slight modification of the incisal area, achieved by moving 14  the incisal height of contour further gingivally, also enhances the illusion of a shorter tooth. 3. The opposite principle is true for increasing the apparent length of a tooth. The heights of contour are moved farther apart incisogingivally (Fig. 3C). A B C Normal Shortening Lengthening Fig. 3 Creating illusions of length. A, Normal length. B, A tooth can be made to appear shorter by emphasizing horizontal elements and by positioning the gingival height of contour further incisally. C, The illusion of length is achieved by moving the gingival height of contour gingivally and by emphasizing vertical elements, such as developmental depressions. II. Symmetry and Proportionality The overall esthetic appearance of a human smile is governed largely by the symmetry and proportionality of the teeth that constitute the smile. Symmetry Assuming that the patient’s teeth are aligned normally (i.e. rotations or faciolingual positional defects are not present), dental symmetry can be maintained if the sizes of contralateral teeth are equivalent. Clinical Notes A dental caliper should be used in conjunction with any conservative esthetic dental procedure that would alter the mesiodistal dimension of the teeth (Fig. 4). When dealing with restorations involving the midline, 15  particular attention also must be paid to: ▪ Incisal and gingival embrasure forms ▪ Mesial contours of both central incisors must be mirror images of one another. A B Fig. 4 Diastema closure. A, Teeth before composite additions. B, Symmetric and equal contours are achieved in the final restorations. Proportionality Anterior teeth must be in proper proportion to one another to achieve maximum esthetics. One long- accepted theorem of the relative proportionality of maxillary anterior teeth typically visible in a smile involves the concept of the golden proportion. On the basis of this formula, a smile, when viewed from the front, is considered to be esthetically pleasing if each tooth in that smile (starting from the midline) is approximately 60% of the size of the tooth immediately mesial to it. The exact proportion of the distal tooth to the mesial tooth is 0.618 (Fig. 5) Clinical Notes These recurring esthetic dental proportions are based on the apparent sizes of teeth when viewed straight on and not the actual sizes of individual teeth. 16  According to a survey, a recurring esthetic dental proportion of 70% (as opposed to 61.8 % as with the golden proportion) is preferred when teeth are of normal dimension. A B C D E F Fig. 5 Tooth proportions. A, The rule of the golden proportion. The exact ratios of proportionality. B, The anterior teeth of this patient are in golden proportion to one another, Width-to-length ratios. Preoperative view reveals width-to-length ratio of 1:1. D, Following a periodontal surgical crown lengthening procedure, a more esthetic width-to-length ratio of 0.80 exists. E, Final result with etched porcelain veneers. A width-to-length ratio of 0.80 is maintained. F, A 7-year postoperative view reveals a stable and esthetic long-term result. Width to Length Ratio 17 An accepted theorem maintains that the ideal width-to-length ratio should be 0.75-0.80 (Fig. 5C through F). The recommended width-to-length ratio for achieving esthetically pleasing maxillary incisors are: Maxillary central incisors: 0.80 Maxillary lateral incisors: 0.75 III. Position and Alignment The overall harmony and balance of a smile depend largely on proper position of teeth and their alignment in the arch. Minor rotations or malposed teeth can be corrected by reducing the enamel in the area of prominence and augmenting the deficient area with composite resin (Fig. 6 A and B). Teeth in mild linguoversion can be treated by augmentation with full facial veneers placed directly with composite or made indirectly from processed composite or porcelain (Fig. 6 C and B). Fig. 6 Position and alignment. A, A minor rotation is first treated by reducing enamel in the area of prominence. B, The deficient area is restored to proper contour with composite. C, Maxillary lateral incisor is in slight linguoversion. D, Restorative augmentation of facial surface corrects malposition. Clinical Notes Care must be exercised in maintaining physiologic gingival contours that do not impinge on tissue or result in an 18  improper emergence profile of the restoration. A functional incisal edge should be maintained by ap- propriate contouring of the restoration (an excessively thick incisal edge should be avoided). Individual teeth that are significantly displaced facially are best treated orthodontically. IV. Surface Texture The character and individuality of teeth are determined largely by their surface texture and existing characteristics. Teeth in young individuals characteristically exhibit significant surface characterization, whereas teeth in older individuals tend to possess a smoother surface texture caused by abrasional wear. The surfaces of natural teeth typically break up light and reflect it in many directions. Clinical Notes Anatomic features should be examined closely and reproduced to the extent that they are present on the surrounding surfaces. The restored areas of teeth should reflect light as in the unrestored adjacent surfaces. V. Color Color is defined as a perception by an observer of the distribution of wavelengths. The interaction of visible light with any material involves reflection, refraction, absorption (and fluorescence), or transmission. An individual’s eye is capable of sensing dominant wavelength, luminous reflectance (intensity), and excitation 19 purity. Color traditionally has been measured using the Munsell color system in terms of hue, value, and chroma. Hue is the intrinsic quality or shade of the color and corresponds to the dominant wavelength. Value refers to the relative lightness or darkness of a hue and corresponds to the luminous reflectance (intensity). It is determined by the amount of white or black in a hue. Some current shade guides are based first on value because of the importance of this element of color. Chroma is the intensity of any particular hue and corresponds to excitation purity Clinical Considerations of Color ▪ A gradation of color usually occurs from the gingival region to the incisal region, with the gingival region being typically darker because of thinner enamel. ▪ Exposed root surfaces are particularly darker (i.e. dentin colored) because of the absence of overlying enamel. ▪ In most individuals, canines are slightly darker than are incisors. ▪ Young individuals with thick enamel characteristically exhibit lighter teeth than older individuals. ▪ Individuals with darker complexions usually appear to have lighter teeth because of the contrast that exists between teeth and the surrounding facial structures. ▪ Women can enhance the apparent lightness of their teeth simply by using a darker shade of makeup or lipstick (Fig. 7). ▪ Color changes associated with aging also occur, primarily owing to wear. As the facial enamel is worn away, the underlying 20  dentin becomes more apparent, resulting in a darker tooth. Cervical areas also tend to darken because of abrasion. ▪ Shade selection should be determined before isolating teeth so that color variations that can occur as a result of drying and dehydration of teeth are avoided. ▪ On extended viewing of a particular tooth site, eyes experience color fatigue, resulting in a loss of sensitivity to yellow-orange shades. By looking away at a blue object or background (i.e. the complementary color), the dentist’s eyes quickly recover and are able to distinguish subtle variations in yellow-orange hues again. ▪ Accurate shade selection is best attained by applying and curing a small amount of the composite restorative material in the area of the tooth that may need restoration. Fig. 7 Illusion of a lighter appearance of teeth by use of darker makeup. A, Before. B, After VI. Translucency The degree of translucency is related to how deeply light penetrates into the tooth or restoration before it is reflected outward. Normally, light penetrates through enamel into dentin before being reflected outward (Fig. 9 A); this affords the realistic esthetic vitality characteristic of normal, unrestored teeth. 21 Shallow penetration of light often results in loss of esthetic vitality. Fig. 8 Schematic summary of interactions of electromagnetic radiation with materials. The color perceived by the observer is the result of several interactions between substrate and incoming radiation producing reflection, internal scattering, absorption, fluorescence, and transmission. A B Fig. 9 Translucency and light penetration. A, Light normally penetrates deeply through enamel and into dentin before being reflected outward. This affords realistic esthetic vitality. B, Light penetration is limited by opaquing resin media under veneers. Esthetic vitality is compromised. Clinical Notes 22 Illusions of translucency also can be created to enhance the realism of a restoration. Color modifiers (also referred to as tints) can be used to achieve apparent translucency and tone down bright stains or to characterize a restoration (Fig. 10). A B Fig. 10 Use of internally placed color modifiers. A, Maxillary right central incisor exhibits bright intrinsic yellow staining as a result of calcific metamorphosis. B, Color modifiers under direct-composite veneer reduce brightness and intensity of stain and simulate vertical areas of translucency. 23 Correction of Diastemas The most frequent site of a diastema is between maxillary central incisors (Fig. 17.12). Etiology A prominent labial frenum with nonelastic fibers extending proximally often prevents the normal approximation of erupting central incisors. Other causative factors include congenitally missing teeth, undersized or malformed teeth, interarch tooth size discrepancies, supernumerary teeth, and heredity. Diastemas also may result from other problems such as tongue thrusting, periodontal disease, or posterior bite collapse. A B C D E F G H I 24 J K L Fig. 11 Diastema closure. A, Esthetic problem created by space between central incisors. B and C, Interdental space and size of central incisors measured with caliper. D, Teeth isolated with cotton rolls and retraction cord tucked into gingival crevice. E, A diamond instrument is used to roughen enamel surfaces. F, Etched enamel surface indicated by arrowhead. G, Composite inserted with composite instrument. H, Matrix strip closed with thumb and forefinger. I, Composite addition is cured. J, Finishing strip used to finalize contour of first addition. K, A tight contact is attained by displacing the second tooth being restored in a distal direction with thumb and forefinger, while holding matrix in contact with adjacent restoration. L, Flame-shaped finishing bur used to contour restoration. Treatment Traditionally, diastemas have been treated by surgical, periodontal, orthodontic, and prosthetic procedures. In carefully selected cases, a more practical alternative is the use of the acid-etch technique and composite augmentation of proximal surfaces M N O P Q Fig. 11 Diastema closure. M, Finishing strip used to smooth subgingival areas. N, Restoration is polished with rubber abrasive point. O, Final luster attained 25 with polishing paste applied with prophy cup. P, Unwaxed floss used to detect any excess composite. Q, Diastema closed with symmetric and equal additions of composite. ▪ Preoperative considerations Photographs, computer imaging, models with spaces filled, and direct temporary additions of ivory-colored wax or composite material on natural teeth (unetched) are important preliminary procedures. ▪ Clinical procedure The correction of a diastema between maxillary central incisors is described and illustrated in Fig. 11. Step 1: After the teeth are cleaned and the shade selected, a suitable caliper is used to measure the width of the diastema and the individual teeth (Fig. 11A and C). Step 2: With cotton rolls in place, a gingival retraction cord of an appropriate size is tucked in the gingival crevice of each tooth from midfacial mesially to midlingual (Fig. 11D). The cord retracts the soft tissue and prevents seepage from the crevice. Step 3: To enhance retention of the composite, a coarse, flame- shaped diamond instrument is used to roughen the proximal surfaces, extending from the facial line angle to the lingual line angle. Step 4: The enamel is acid-etched approximately 0.5 mm past the prepared, roughened surface. The acid should be applied gingivally only to the extent of the anticipated restoration. After rinsing and drying, the etched enamel should display a lightly frosted appear- ance. Step 5: A 2x2 inch ( 5 x 5 cm) gauze is draped across the mouth 26 and tongue to prevent inadvertent contamination of the etched preparations by the patient. Step 6: A polyester strip matrix is contoured and placed proximally, with the gingival aspect of the strip extending below the gingival crest. Additional contouring may be required to produce enough convexity in the strip. In most cases, a wedge cannot be used. The strip is held (with the index finger) on the lingual aspect of the tooth to be restored, while the facial end is reflected for access. Step 7: After the bonding agent is applied, the composite material is inserted with a hand instrument (Fig. 11G). Careful attention is given to pressing the material lingually to ensure confluence with the lingual surface. Step 8: The matrix is gently closed facially, beginning with the gingival aspect. The light- cured composite material is polymerized with the light directed from the facial and lingual directions for an appropriate amount of time. Step 9: Contouring and finishing are achieved with appropriate carbide finishing burs, fine diamonds, or abrasive disks (Fig. 11L). Finishing strips are invaluable for finalizing the proximal contours.. Flossing with a length of unwaxed floss verifies that the gingival margin is correct and smooth if no fraying of the floss occurs (Fig. 11 P). Step 10: After etching, rinsing, and drying, the second restoration is completed. A tight proximal contact can be attained by displacing the second tooth being restored in a distal direction (with the thumb and the index finger) while holding the matrix in 27 contact with the adjacent restoration (Fig. 11K). Contouring is accomplished with a 12-fluted carbide bur and finishing strips (Fig. 11L and M). Step 11: Articulating paper should be used to evaluate the patient’s occlusion and adjustments can be made with a carbide finishing bur or abrasive disks. Step 12: Final polishing is achieved with rubber polishing points or polishing paste applied with a Pro- phy cup in a low-speed handpiece (Fig. 11 O). The final esthetic result is seen in Fig. 17.12Q Cotton rolls, instead of a rubber clam, are recommended for isolation because of the importance of relating the contour of the restoration directly to the proximal tissue. Usually, the restoration must begin slightly below the gingival crest to appear natural and to be confluent with the tooth contours. Initially, it is better to overcontour the first restoration slightly to facilitate finishing it to an ideal contour. A B 28  C D Fig. 12 Space distribution A, Midline diastema too large for simple closure with composite additions. B and C, Space distributed among four incisors with orthodontic treatment. D, Final result after composite addition. It is imperative for good gingival health that the cervical aspect of the composite addition be immaculately smooth and continuous with the tooth structure Diastemas which are simply too large to close esthetically with composite augmentation alone (Fig. 12) are best redistributed orthodontically first prior to composite correction of the remaining diastemas (Fig. 12, B to D). Conservative Treatments for Discolored Teeth One of the most frequent reasons patients seek dental care is discolored anterior teeth. Treatment options include removal of surface stains, bleaching, microabrasion or macroabrasion, veneering, and placement of porcelain crowns. Discolorations are classified as extrinsic or intrinsic. Extrinsic stains are located on the outer surfaces of teeth, whereas intrinsic stains are internal. I. Extrinsic Discoloration Etiology Stains on the external surfaces of teeth are common and may be the result of numerous factors. In young patients, stains of almost any color can be found and 29  are usually more prominent in the cervical areas of teeth (Fig. 17.14). These stains may be related to remnants of Nasmyth’s membrane, poor oral hygiene, existing restorations, gingival bleeding, plaque accumulation, eating habits, or the presence of chromogenic microorganisms. Fig. 13 Extrinsic stains: Surface stains on facial surfaces in a young patient In older patients, stains on the surfaces of teeth are more likely to be brown, black, or gray and occur on areas adjacent to gingival tissue. Permeability of teeth usually allows the infusion (over time) of significant organic pigments (from chromogenic foods, drinks like coffee and tea, and tobacco products) that produce a yellowing effect. Poor oral hygiene is a contributing factor that can produce stains (even on plaque-free surfaces). Tobacco stains is a common cause of extrinsic tooth discoloration especially on the palatal and cervical areas. Existing leaking restorations may be discolored due to microleakage. Treatment Most surface stains can be removed by routine prophylactic procedures. Some superficial discolorations on tooth-colored restorations and decalcified areas on teeth, however, cannot be corrected by such cleaning. Conservative correction may be 30 accomplished by mild microabrasion or by macroabrasion followed by polishing with abrasive disks or points to obtain an acceptable result. II. Intrinsic Discoloration Etiology Intrinsic discolorations are caused by deeper (not superficial) internal stains or enamel defects; these stains are more complex to treat than are external types. Teeth with vital or nonvital pulps as well as root canal-treated teeth can be affected. Vital teeth discoloration The staining may be located in enamel or dentin. Discolorations restricted to dentin still may show through enamel. Discoloration also may be localized or generalized, involving the entire tooth. ▪ During tooth development Vital teeth may be discolored at the time the crowns are forming, and the abnormal condition usually involves several teeth. Causative factors include: Hereditary disorders: Amelogcnosis imperfecta and dentinogenesis imperfecta High fevers associated with early childhood illnesses Other types of trauma. ▪ Tetracycline staining Staining from tetracycline-type drugs most frequently occurs at an early age and is caused by ingestion of the drug concomitant with the development of permanent teeth (Fig. 14). The severity of the staining depends on the dose, the duration of exposure to the drug, and the type of tetracycline analogue used. Different types of tetracyclines induce different types of discoloration, varying from 31 yellow-orange to dark blue-gray. A B Fig. 14 Intrinsic stains. A, Staining by tetracycline drugs. B, Staining of maxillary left central incisor from tooth trauma and degeneration of the pulp. ▪ Fluorosis The presence of excessive fluoride in drinking water and other sources at the time of teeth formation can result in another type of intrinsic stain called fluorosis. The staining usually is generalized. ▪ Age Aging effects also can result in yellowed teeth. a. As individuals grow older, the tooth enamel becomes thinner because of wear and allows underlying dentin to become more apparent. b. Continuing deposition of secondary dentin occurs in older individuals, resulting in greater dentin thickness. This deposition results in a yellowing effect, depending on the intrinsic color of dentin. Nonvital teeth discoloration Nonvital teeth also can become discolored intrinsically. These stains usually occur in individual teeth after eruption has taken place. ▪ Necrosis of pulp 32 The pulp may become infected or degenerate as a result of trauma, deep caries, or irritation from restorative procedures. If these teeth are properly treated by root canal therapy, they usually retain their normal color. If treatment is delayed, discoloration of the crown is more likely to occur. The degenerative products from the pulp tissue stain dentin, and this is readily apparent because of the translucency of enamel (see Fig. 14.B). ▪ Trauma a. Trauma resulting in calcific metamorphosis (i.e. calcification of the pulp chamber, root canal, or both) also can produce significant yellowing of the tooth. This condition is extremely difficult to treat (see Fig. 1o.A). b. Trauma may cause the blood vessels in the pulp to rupture, with diffusion of blood into the dentinal tubules. Such teeth have a dark pinkish hue almost immediately after the accident and turn pinkish brown some days afterward. ▪ Staining from root canal medicaments Certain root canal medicaments may cause discoloration. Some stain the tooth directly, whereas others stain only on decomposing or combining with some other agents used in endodontic treatment. Treatment Mild discolorations are best left untreated, are bleached, or are treated conservatively with microabrasion or macroabrasion because no restorative material is as good as the healthy, natural tooth structure. A suntan, darker makeup, or darker lipstick 33 usually makes teeth appear much whiter by increasing the contrast between the teeth and the surrounding facial features (Fig. 15-B). A B Fig. 15 Illusion of a lighter appearance of teeth by use of darker makeup. A, Before. B, After. Patients should be informed of the life expectancy of the various treatment alternatives suggested. Vital bleaching usually results in tooth lightening for only 1-3 years, whereas an etched porcelain veneer should last 10-15 years or longer. The clinical longevity of esthetic restorations also is enhanced in patients with good oral hygiene, proper diet, a favorable bite relationship, and little or no contact with agents that cause discoloration or deterioration. Treatment of discolored teeth Polishing Bleaching Micro abrasion Macro abrasion Veneer 34 Bleaching Treatments The lightening of the color of a tooth through the application of a chemical agent to oxidize the organic pigmentation in the tooth is referred to as bleaching. Indications for Bleaching 1. Generalized staining 2. Ageing 3. Smoking and dietary stains such as those of tea and coffee; 4. Fluorosis 5. Tetracycline staining 6. Traumatic pulpal changes. Classification of Bleaching Treatments Nonvital bleaching procedures 1. In-office nonvital bleaching technique (Thermo- catalytic bleaching) 2. Walking bleach technique Vital bleaching procedures 1. In-office vital bleaching technique 2. Dentist-prescribed, home-applied technique Mechanism of Bleaching Most bleaching techniques use some form or derivative of hydrogen peroxide in different concentrations and application techniques. The mechanism of action of bleaching teeth with hydrogen peroxide is considered to be oxidation of organic pigments. 35 Clinical Notes Bleaching generally has an approximate lifespan of 1-3 years, although the change may be permanent in some situations. With all bleaching techniques, a transitory decrease occurs in the potential bond strength of composite when it is applied to bleached enamel and dentin. This reduction in bond strength results from residual oxygen or peroxide residue in the tooth that inhibits die setting of the bonding resin, precluding adequate resin tag formation in the etched enamel. No loss of bond strength is noted if the composite re- storative treatment is delayed at least 1 week after cessation of any bleaching. I. Nonvital Bleaching Procedures Nonvital bleaching techniques include an in-office technique referred to as thermocatalytic bleaching and a safer alternative that is known as walking bleach technique. 1. In-office Nonvital Bleaching Technique (Thermocatalytic bleaching) Concept The in-office bleaching for nonvital teeth historically has involved a thermocatalytic technique consisting of the placement of 35% hydrogen peroxide liquid soaked in cotton pads into the debrided pulp chamber as well as on the labial tooth structure. The bleaching process is accelerated by the placement of a heating 36 instrument on top of the soaked cotton pads. Clinical technique The thermocatalytic technique is not recommended, however, because of the potential for external cervical resorption (Fig. 16). A more current technique uses 30-35% hydrogen peroxide pastes or gels that require no heat. This technique is frequently the preferred in-office technique for bleaching nonvital teeth. Fig. 16 Radiograph revealing the presence of extensive cervical resorption. Clinical Notes It is imperative that a scaling cement (resin-modified glass ionomer {RMGI] cement is recommended) be placed over the exposed root canal filling before application of the bleaching agent to prevent leakage and penetration of the bleaching material in an apical direction. It is also recommended that the bleaching agent be applied in the coronal portion of the tooth incisal to the level of the periodontal ligament (not down into the root canal space) to prevent unwanted leakage of the bleaching agent through the lateral canals or canaliculi to the periodontal ligament. 2. Walking Bleach Technique Concept The walking bleach technique is an in-office bleaching procedure 37 that does not require the use of heat and employs sodium perborate as the bleaching agent. The bleaching process is slower and continues till the patient reports back for the subsequent appointment for assessment and cessation of the treatment (hence the name ‘walking bleach’) (see Fig. 17). A B Fig. 17 Indication for bleaching root canal–filled tooth. A, Before. B, After intracoronal, nonvital bleaching. Clinical procedure Step 1: Isolation and access refinement The dentist places a rubber dam to isolate the discolored tooth and removes all materials from the access opening (Fig. 18 A). The dentist removes gutta-percha (to approximately 1-2 mm apical of the clinical crown) and enlarges the endodontic access opening sufficiently to ensure complete debridement of the pulp chamber (Fig 18 B). Step 2: Coronal sealing cement The dentist places an RMGI liner to seal the gutta-percha of the root canal, filling from the coronal portion of the pulp chamber (Fig. 18 C). 38  Fig. 18 Walking bleach: A, Nonvital discoloration of dentin B, The access cavity preparation is modified and gutta-percha is removed apically to just below the cervical margin. The pulp horns are cleaned with a round bur. C, A protective sealing cement is placed over the gutta-percha, not extending above the cervical margin. A paste composed of sodium perborate and saline (mixed to the consistency of creamy paste) is placed. The incisal area is undercut to retain the temporary restoration. D, A temporary filling seals the access. E, A permanent restoration is placed when the desired bleaching effect has been achieved. Step 3: Sodium perborate bleaching Sodium perborate is used with this technique because it is deemed extremely safe. Using a cement spatula, with heavy pressure on a glass slab, one drop of saline is blended with enough sodium perborate to form a creamy paste. A spoon excavator is used to fill the pulp chamber (with the bleaching mixture) to within 2 mm of the cavosurface margin, avoiding contact with the enamel cavosurface margins of the access opening. Step 4: Temporary seal The dentist uses a cotton pellet to blot the mixture and places a 39 temporary sealing material to seal the access opening (Fig. 18 D). Step 5: Interappointment schedule The sodium perborate should be changed weekly. On successful bleaching of the tooth, the chamber is rinsed and hi led to within 2 mm of the cavosurface margin with a paste consisting of calcium hydroxide powder in sterile saline to reduce the possibility of resorption.11 The dentist reseals the access opening with a temporary restorative material, as previous described, and allows the calcium hydroxide material to remain in the pulp chamber for 2 weeks. Step 6: Final coronal restoration Subsequently, the dentist removes the temporary restorative material, rinses away the calcium hydroxide, and dries the pulp chamber. Next, the dentist etches enamel and dentin and restores the tooth with a light-cured composite (Fig. 18 E). II. Vital Bleaching Procedures Vital bleaching techniques include an in-office technique referred to as power bleaching and an outside the office alternative that is a “dentist-prescribed, home- applied” technique (i.e. nightguard vital bleaching, or simply “at-home bleaching”). These techniques may be used separately or in combination with one another. 1. In-office Vital Bleaching Technique Advantages a) This procedure is totally under the dentist’s control and the soft tissue can be generally protected from the process. 40  b) This technique has the potential for bleaching teeth more rapidly. Disadvantages a) Cost of the treatment b) The unpredictable outcome c) Unknown duration of the treatment. Clinical technique Step 1: Rubber dam isolation In-office vital bleaching requires an excellent rubber dam technique and careful patient manage patient’s lips and gingival tissue before application of the rubber dam to help protect these soft tissues from any inadvertent exposure to the bleaching agent. Step 2: 30-35% hydrogen peroxide bleaching The dentist places the 30-35% hydrogen peroxide- containing paste or gel on teeth. The patient is instructed to report any sensations of burning of the lips or gingiva that would indicate a leaking dam and the need to terminate treatment. Step 3: Light activation (optional step) Use of a light to generate heat may accelerate the oxidation reaction of the hydrogen peroxide and expedite treatment through a thermocatalytic effect. PAC lights and highlight-output quartz halogen lights have been commonly used for this purpose. Use of lights to heat the bleaching agent, however, causes a greater level of tooth dehydration. This effect not only can increase tooth sensitivity but also results in an immediate apparent whitening of the tooth owing to dehydration that makes the actual whitening result more difficult to assess. Step 4: Duration of treatment 41 Contrary to the claims of some manufacturers, optimal whitening typically requires more than one bleaching treatment. Bleaching treatments generally are rendered weekly for two to six treatments, with each treatment lasting 30-45 minutes. Step 5: Postoperative considerations On completion of the treatment, the dentist rinses the patient’s teeth, removes the rubber dam or isolation medium, and cautions the patient about postoperative sensitivity. A nonsteroidal analgesic and anti-inflammatory drug may be administered if sensitivity is anticipated. Most of the credible research indicates that the addition of light during the bleaching procedure does not improve the whitening result beyond what the bleach alone can achieve. Use of carbon dioxide laser to heat the bleaching mixture and accelerate the bleaching treatment has not been recommended, because of the potential for hard or soft tissue damage. The features that warrant concern and caution include: Potential for soft tissue damage to both patient and provider Discomfort caused by the rubber dam or other isolation devices Potential for post-treatment sensitivity. 2. Dentist-prescribed, Home-applied Technique Advantages The use of a lower concentration of peroxide (generally 10- 15% carbamide peroxide) Ease of application Minimal side effects 42  Lower cost because of the reduced chair time required for treatment. Disadvantages i. Reliance on patient compliance ii. Longer treatment time iii. The (unknown) potential for soft tissue changes with excessively extended use. Clinical technique Step 1: Fabrication of vinyl custom night guard An impression of the arch to be treated is made and poured in cast stone. The nightguard is formed on the cast with the use of a heated vacuum-forming machine. A sheet of 0.75-1.5 mm soft vinyl nightguard material is used to create the custom nightguard (Fig. 19). The dentist inserts the nightguard into the patient’s mouth and evaluates it for adaptation, rough edges, or blanching of tissue. A properly fitting nightguard is shown in Fig. 20. Fig. 19 Vacuum-formed, clear plastic nightguard used for vital bleaching Step 2: Carbamide peroxide bleaching A 10-15% carbamide peroxide bleaching material generally is recommended for this 43 bleaching technique. Carbamide peroxide degrades into 3% hydro- gen peroxide (active ingredient) and 7% urea. Bleaching materials containing carbopol are recommended because carbopol thickens the bleaching solution and extends the oxidation process. A B Fig. 20 Nightguard for vital bleaching. A and B, Clear plastic nightguard properly seated and positioned in the mouth (scalloped on facial, unscalloped on lingual). Step 3: Clinical application The patient is instructed in the application of the bleaching gel or paste into the nightguard. A thin bead of material is extruded into the nightguard along the facial aspects corresponding to the area of each tooth to be bleached. Usually, only the anterior six to eight teeth are bleached. No excess material should be allowed to remain on soft tissue because of the potential for gingival irritation. The patient should be informed not to drink liquids or rinse during treatment and to remove the nightguard for meals and oral hygiene. Step 4: Mode and duration of treatment ▪ Most patients prefer an overnight treatment approach because of the convenience. If the nightguard is worn at night, a single application of bleaching material at bedtime is indicated. In the morning, the patient should remove the nightguard, clean it under running water with a toothbrush, and store it in the container pro- vided. Total treatment time using an overnight approach is usually 44 1-2 weeks. Fig. 21 illustrates a typical case before and after treatment with nightguard vital bleaching. ▪ If patients cannot tolerate overnight bleaching, the bleaching time and frequency can be adjusted for daytime bleaching to accommodate the patient’s comfort level. ▪ If either of the two primary adverse effects occurs—sensitive teeth or irritated gingiva, the patient should reduce or discontinue treatment immediately and contact the dentist so that the cause of the problem can be determined and the treatment approach modified. A B Fig. 21 Nightguard vital bleaching. A, Before bleaching treatment. B, After. ROABRASIONCROABRASION AND Microabrasion and Macroabrasion Concept Microabrasion and macroabrasion represent conservative alternatives for the reduction or elimination of superficial discolorations. As the terms imply, the stained areas or defects are abraded away. These techniques result in the physical removal of the tooth structure and are indicated only for stains or enamel defects that do not extend beyond a few tenths of a millimeter in depth. If the defect or discoloration remains even after treatment 45 with microabrasion or macroabrasion, a restorative alternative is indicated. Microabrasion This technique involves the physical removal of tooth structure and does not remove stains or defects through any bleaching phenomena. Materials Employed In 1984, McCloskey reported the use of 18% hydrochloric acid swabbed on teeth for the removal of superficial fluorosis stains. Croll and Cavanaugh (1986) modified the technique—18% hydrochloric acid + pumice to form a paste applied with a tongue blade. This technique is called microabrasion and involves the surface dissolution of the enamel by acid along with the abrasiveness of the pumice to remove superficial stains or defects. Croll’s modified technique 11% Hydrochloric acid + silicon carbide particles (in a water-soluble gel paste). This combination uses a decreased concentration of HCL and increases the abrasiveness of the paste. This product, marketed as Prema compound. Clinical Procedure Before treatment, the clinician should evaluate the nature and extent of the enamel defect or stain and differentiate between nonhereditary developmental defects (e.g. white or light brown fluorotic enamel and the idiopathic white or light brown spot) versus incipient carious lesions. 46 A developmental discolored spot (opaque white or light brown) is the result of an unknown, local traumatic event during amelogenesis and is termed idiopathic. Its surface is intact, smooth, and hard. It usually is located in the incisal (occlusal) half of enamel, which contributes to the unsightly appearance. A B C D E F G H Fig. 22 Microabrasion. A, Young patient with unesthetic fluorosis stains on central incisors. B and C, Prema compound applied with special rubber cup with fluted edges. Protective glasses and rubber dam are needed for safety of the patient. D, Hand applicator for applying Prema compound. E, Stain removed from left central incisor after microabrasion. F, Treated enamel surfaces polished with prophylactic paste. G, Topical fluoride applied to treated enamel surfaces. H, Final esthetic result. Incipient caries is reversible if treated immediately. If the caries lesion has progressed to have a slightly roughened surface, however, microabrasion coupled with a remineralization program is an initial option. If this approach is unsuccessful, it can be fol- lowed by a restoration. 47 Surface discolorations resulting from fluorosis also can be removed by microabrasion if the discoloration is within the 0.2-0.8 mm removal depth limit (Fig. 22). Clinical Notes Cavitation of the enamel surface is an indication for restorative intervention. As the location of smooth-surface enamel caries nears the cemento-enamel junction (CEJ), then enamel is too thin to permit microabrasion or macroabrasion as a treatment option. If microabrasion is unsuccessful because of the depth of the defect exceeding 0.2-0.3 mm, the tooth will be restored with a tooth-colored restoration. Macroabrasion An alternative technique to microabrasion for the removal of localized, superficial white spots (not subject to conservative, remineralization therapy) and other surface stains or defects is called macroabrasion. Clinical technique Macroabrasion simply uses a 12-fluted composite finishing bur or a fine grit finishing diamond in a high-speed handpiece with adequate air-water spray to remove the defect (Fig. 23A and B). Care must be taken to use light, intermittent pressure and to monitor the removal of tooth structure carefully lo avoid irreversible damage to the tooth. After removal of the defect or on termination of any further 48 removal of tooth structure, a 30-fluted, finishing bur is used to remove any facets or striations created by the previous instruments. Final polishing is accomplished with an abrasive rubber point (Fig. 23 C). The results are shown in Figure 23 D. Clinical Notes Microabrasion has the advantage of ensuring better control of the removal of tooth structure. Macroabrasion is considerably faster and easier than microabrasion and does not require the use of a rubber dam or special instrumentation. Fig. 23 Macroabrasion. A, Outer surfaces of maxillary anterior teeth are unesthetic because of superficial enamel defects. B and C, Removal of discoloration by abrasive surfacing and polishing procedures. D, Completed treatment revealing conservative esthetic outcome. High-speed instrumentation used in macroabrasion is technique sensitive and can have catastrophic results if the clinician fails to use extreme caution. Microabrasion is recommended over macroabrasion for the treatment of superficial defects in children because of better operator control and superior patient acceptance. 49  To accelerate the process, a combination of macroabrasion and microabrasion also may be considered. Gross removal of the defect is accomplished with macroabrasion, followed by final treatment with microabrasion 50  Veneers Definition A veneer is a layer of tooth-colored material that is applied to a tooth to restore localized or generalized defects and intrinsic discolorations (Fig.24). A B C Fig. 24 Clinical examples of indications for treatment with veneers include teeth affected by tetracycline drug staining (A), fluorosis or enamel hypoplasia (B), and acid-induced erosion (e.g., lemon-sucking habit) (C). Indications Common indications for veneers include teeth with facial surfaces are as follows: Improve extreme discolorations such as tetracycline staining ,flourosis ,devitalized teeth ,and teeth darkened from age. Repair chipped or fractured teeth. Closing of diastemas between teeth. 51  Ability to lengthen anterior teeth Improve the appearance of rotated or misaligned teeth Contraindication If little or no enamel is present, full crown should be considered. Certain tooth-to-tooth habits like bruxing or clenching, or other para-functional habits such as pencil chewing or ice crushing. 52  Teeth that exhibit severe crowding. Certain types of occlusal problems such as Class III & end-to-end bites. Endodontically treated teeth Types of veneers 53  1. Based on the extent of the tooth involved, veneers can be classified as: A. Partial veneers: Partial veneers are indicated for the restoration of localized defects or areas of intrinsic discoloration (Fig. 25 A). B. Full veneers: Full veneers are indicated for the restoration of generalized defects or areas of intrinsic staining involving most of the facial surface of the tooth. Full veneers can be further subdivided based on the preparation design (Fig. 25 B and C) as: a. Window preparation b. Butt joint incisal preparation c. Incisal overlap preparation. 2. Based on the type of material employed, veneers can be classified as: A. Directly applied composite veneer B. Processed composite veneer C. Porcelain, pressed ceramic or machinable ceramic veneer. 3. Based on the mode of fabrication veneers can he classified into: A. Direct veneers a. Direct partial veneers b. Direct full veneers B. Indirect veneers a. No-prep veneers b. Etched porcelain veneers 54  c. Pressed ceramic veneers. Clinical Considerations 1. Patient factors Several important factors, including patient age, occlusion, tissue health, position and alignment of teeth, and oral hygiene, must be evaluated before pursuing full veneers as a treatment option. 2. Indirect vs direct veneers Indirect veneers require two appointments but typically offer three advantages over directly placed full veneers: S Fig. 25 Four types of veneers. A, Facial view of partial veneer that does not extend subgingivally or involve the incisal angle. B, Full veneer with window preparation design that extends to the gingival crest and terminates at the facioincisal angle. C, Full veneer with either a hutt-joint incisal preparation design or an incisal-lapping preparation design extending subgingivally and including all of incisal surface. (Subgingival extension is indicated only for preparation of darkly stained teeth and is not considered routine). D-G, Cross-sections of the four types of veneers: D, Partial veneer; E, Full veneer with window preparation design; F, Full veneer with butt-joint incisal preparation design; G, Full veneer with incisal-lapping incisal preparation 55 design. Indirectly fabricated veneers are much less sensitive to operator technique. Considerable artistic expertise and attention to detail are required to consistently achieve esthetically pleasing direct veneers. Indirect veneers are made by a laboratory technician and are typically more es- thetic. If multiple teeth are to be veneered, indirect veneers usually can be placed much more predictably. Indirect veneers typically last much longer than do direct veneers, especially if they are made of porcelain or pressed ceramic. 3. Preparation depth Intraenamel preparation before placing a veneer is strongly recommended for the following reasons: To provide space for bonding and veneering materials for maximal esthetics without overcontouring. To remove the outer, fluoride-rich layer of enamel that may be more resistant to acid-etching. To create a rough surface for improved bonding. To establish a definite finish line. 4. Location of gingival margin The position of the gingival margin of any veneer is recommended to be supragingival and is dictated by the extent of the defects or discoloration and the amount of tooth structure that is visible with maximum smiling. No restorative material is as good as normal tooth structure, and the gingival 56 tissue is never as healthy when it is in contact with an artificial material. Preparation design a. A window preparation (Fig. 25 E) is recommended for: Most direct composite veneers In cases of indirectly fabricated veneers where the outline form of the canine is intact and the patient is canine guided. b. Butt-joint incisal preparation is used routinely in cases where no defects exist along the lingual aspect of the incisal edge (Fig. 25 F). c. Incisal-lapping preparation is indicated when the tooth being veneered needs lengthening or when an incisal defect warrants restoration (Figs. 25 G). I. Direct Veneer Technique 1. Direct Partial Veneers Small localized intrinsic discolorations or defects that are surrounded by healthy enamel are ideally treated with direct partial veneers. Preliminary steps include cleaning, shade selection, and isolation with cotton rolls or rubber dam. Anesthesia usually is not required unless the defect is deep, extending into dentin. If the entire defect or stain is removed, a nanofilled composite is recommended for restoring the preparation. 2. Direct Complete Veneers Clinical procedure 57  ▪ After the teeth to receive the veneers are cleaned and a shade is selected, the area is isolated with cotton rolls and retraction cords. A B C D Fig. 26 Direct full veneers using light-cured composite. A, Enamel hypoplasia of maxillary anterior teeth. B, Etched preparations of central incisors. C, Veneers completed on maxillary central incisors. D, Treatment completed with placement of full veneers on remaining maxillary anterior teeth. ▪ The teeth are prepared with a course, rounded- end diamond instrument. ▪ The window preparation typically is made to a depth: a. Approximately 0.5-0.75 mm mid facially b. Tapering down to a depth of about 0.3-0.5 nun along the gingival margin, depending on the thickness of enamel. ▪ A well-defined chamfer at a level supragingival to the gingival crest provides a definite preparation margin. 58  ▪ The preparation for all veneer types (both direct and indirect) normally is terminated just facial to the proximal contact except in the case of a diastema (see Fig. 26). II. Indirect Veneer Technique Indirect veneers are primarily made of (i) processed composite, (ii) feldspathic porcelain, and (iii) cast or pressed ceramic. Because of superior strength, durability, and conservation of the tooth structure, feldspathic porcelain bonded to intra-enamel preparations has historically been the preferred approach for indirect veneering techniques used by dentists Clinical Notes Although two appointments are required for indirect veneers, choir time is reduced because much of the work has been done in the laboratory. Excellent results can be obtained when proper clinical evaluation and careful operating procedures are followed. Indirect veneers are attached to the enamel by acid etching and bonding with light-cured resin cement. ❖ No-prep Veneers Concept One approach being used for indirect veneers is to place them on teeth with no tooth preparation. Indications No-prep veneers are best used when teeth are inherently undercontoured, when interdental spaces or open incisal embrasures are present, or when both conditions exist. Example 59 of successful no-prep veneers following these guidelines is seen in Figure 27. Fig. 27 No-prep veneers placed on maxillary anterior teeth. A, Before treatment. B, Immediately after placement of the no-prep veneers. No-prep veneers can be problematic because of the following reasons: ▪ First, no-prep veneers are inherently made thinner and, consequently, are more prone to fracture, especially during the try-in phase, ▪ Second, for indirect no-prep veneers, interproximal areas are difficult to access for proper finishing. ▪ Third, if case selection is not done properly and the teeth are already of normal contour, the resulting veneers inevitably will be overcontoured ❖ Etched Porcelain Veneers Concept The preferred type of indirect veneer is the etched porcelain (i.e. feldspathic) veneer. Porcelain veneers etched with hydrofluoric acid are capable of achieving high bond strengths to the etched enamel via a resin-bonding medium. Etched porcelain veneers are 60 highly esthetic, stain resistant, and periodontally compatible. Clinical procedures Step 1: Preoperative considerations i. A consult appointment is always recommended for shade selection, intraoral photographs, and impressions for diagnostic models and occlusal records. ii. An incisal reduction index is always recommended to accurately gauge the amount of incisal reduction during the preparation of teeth for etched porcelain veneers (Fig. 28 A through H). Step 2: Instrumentation The veneer preparation is made with a tapered, rounded-end diamond instrument. A diamond with a tip diameter of 1.0-1.2 mm is recommended. Step 3: Clinical considerations i. The intraenamel preparations are made to a depth of approximately 0.5-0.75 mm midfacially, diminishing to a depth of 0.3-0.5 mm along the gingival margins, depending on enamel thickness. ii. Veneer interproximal margins should be located just facial to the proximal contacts. 61 Fig. 29 (continue) 62 Fig. 29 (continue) 63 Fig. 29 Etched porcelain veneers using an intraenamel preparation. A, A patient with severe dental fluorosis. B, An incisal reduction index is made 64 intraorally, C, Retraction cord is placed. D, The outline form. E-G, Facial reduction is attained. H, Incisal reduction is verified using the incisal reduction index. I, Finished preparations for intraenamel preparations. Note the window preparations on canines and premolars. J, Retraction cord is placed for isolation. K, The fit of the veneer is assessed. L and M, Etching of the prepared maxillary central incisors. N and O, Adhesive is applied to the etched enamel and the tooth side of the porcelain veneer. P, The veneer is loaded with resin cement and seated on the tooth. Q, Excess cement is removed with a microbrush. R, Excess cement is removed interproximally through removal of polyester strip. S, Resin cement cured with intense curing light. T, No. 12 surgical blade in a Bard-Parker handle is used for removing excess cured resin cement. U and V, Diamond instruments used to ‘dress’ marginal areas. W and X, 30-fluted carbide burs and diamond impregnated polishing instruments used to finish and polish veneer margins. Y and Z, Finished etched porcelain veneers as viewed from the lingual and facial aspects. Step 4: Impressions and temporization i. After the preparations are completed, an elastomeric impression is made. ii. In most cases, temporaries are fabricated for the prepared teeth. Step 5: Veneer trial and cementation 1. After they have been fabricated in the laboratory, the porcelain veneers are returned to the dentist for cementation at the second appointment. 2. After the prepared teeth are cleaned with a pumice slurry, rinsed, and dried and isolated. A 2x2 inch cotton gauze is placed across the back of the patient’s mouth to protect against aspira- tion or swallowing of an inadvertently dropped veneer. 3. The fit of each veneer is evaluated on the respective individual tooth and adjusted if necessary. 4. Prior to cementation, a silane coupling agent can optionally be applied to the internal surfaces of the veneers to increase the bond strength of the resin to the porcelain. 65 5. A light-cured resin cement is recommended for bonding the veneer to the tooth. The step wise preparation and insertion of etched porcelain veneers are illustrated in Figure 29. ❖ Pressed Ceramic Veneers Concept In contrast to etched porcelain veneers that are fabricated by stacking and firing feldspathic porcelain, pressed ceramic veneers arc literally cast using a lost wax technique (e.g. IPS Empress or e.max [Ivoclar Vivadent]). Clinical Notes Excellent esthetics is possible using pressed ceramic materials for most cases involving mild to moderate discoloration. Because of the more translucent nature of pressed ceramic veneers, however, dark discolorations are best treated with etched porcelain veneers. The clinical technique for placing pressed ceramic veneers (e.g. IPS Empress) is similar to that for feldspathic porcelain veneers, other than the need for a slightly greater tooth reduction depth. The procedures for tooth preparation, try-in, and bonding of pressed veneers are the same as for etched porcelain veneers except that the marginal fit is superior 66 Chapter 2  ANTERIOR COMPOSITE RESTORATION ▪ INDICATIONS Class III, IV and V. Aesthetic improvement procedures: a. Partial veneers b. Full veneers c. Treatment of tooth discolorations d. Diastema closures Erosion or abrasion defects in cervical areas. Hypoplastic defects. As core build up. For periodontal splinting of mobile teeth. For repair of fractured ceramic crowns For bonding orthodontic appliances. ▪ CONTRAINDICATIONS When isolation of operating field is difficult. Where very high occlusal forces are present. When lesion extends up to the root surface. Small lesions on distal surface of canines where metallic restoration is treatment of choice. Patients with high caries susceptibility. When preparation extends subgingivally. Patients with poor oral hygiene. 67  ▪ ADVANTAGES Conservative to tooth structure. Aesthetically acceptable. Less complex tooth preparation is required. Composite resin can be used in combination with other materials, such as glass ionomer, to provide the benefits of both materials. Composites have low thermal conductivity, thus no insulation base is required to protect underlying pulp. Bonded with enamel and dentin, hence show good retention. Can be finished immediately after curing. Repairable. They have extended working time, this makes their manipulation easier. Restoration can be completed in one dental visit. No galvanism because composite resins do not contain metals. Composite resins have adequate radiopacity to enable their detection in radiographs. ▪ DISADVANTAGES Because of polymerization shrinkage, gap formation on margins may occur, usually on root surfaces. This can result in secondary caries and staining. More difficult, time consuming. Expensive than amalgam. More technique sensitive. Low wear resistance. Postoperative sensitivity due to polymerization shrinkage. High LCTE may results in marginal percolation around composite restorations. 68 CLINICAL PROCEDURES FOR RESTORATION OF CLASS IV Fig. 1: Class IV pre and post-operative 69  For achieving optimal results, thorough examination, diagnosis and treatment plan should be finalized before initiating composite restoration. Following steps are undertaken for composite restoration: Steps of clinical proceduring for composite restoration 1. Local anaesthesia 2. Preparation of operating site 3. Composite selection 4. Shade selection 5. Isolation 6. Tooth preparation 7. Bonding 8. Composite placement 9. Final contouring, finishing and polishing of composite restoration 1. Local Anaesthesia As and when required, local anaesthesia is given in many cases since it makes the procedure pleasant, time saving and besides reducing the salivation. 2. Preparing the Operating Site Operating site is cleaned using slurry of pumice in order to remove plaque, calculus and superficial stains prior to the procedure. Fig. 2: Polishing with pumice 70  3. Composite Selection Composite selection is dependent on: Position of the tooth preparation: For restoration requiring high mechanical performance, like class IV preparations, large class I, II and class VI, choice of composite is that with the highest inorganic load. For restorations of anterior teeth, aesthetics is the main concern. So, composites with submicronic fillers or nanoparticles are preferred in these cases. Composites which are highly polishable are preferred for cervical lesions both in the posterior and in the anterior areas to avoid plaque accumulation on them. Aesthetic requirements: In special cases where aesthetics is the main concern like treatment of defective shape, discolored teeth, diastemas, malpositioned teeth and for caries in anterior teeth, opacity and the translucency of the composites are to be kept in mind for attaining optimal results. 4. Shade Selection For posterior composite restorations shade selection is not that critical as it is for anterior restorations. Sometimes more than one shade is needed to attain optimal aesthetics. The number of shades to be used depends on: Complexity of the restoration Polychromatic characteristics of the tooth to be restored Relationship with adjacent teeth. 71  In cases where the dentin is to be replaced, composites having dentin shade and opacity are preferred while when enamel is to be replaced, composite that has enamel shade and translucency is preferred. One considerable challenge for anterior restorations is shade selection. Generally composite shades are based on the Vita Classical Shade Guide (Vident, Brea, CA, USA). However, this shade guide is not made of composite and its use may lead to a restoration that is not exactly as the planned shade. To overcome this issue, it is suggested to fabricate a custom shade guide using the composite used in the office. To confirm the shade selection, some enamel-like shade composite may be placed on an unetched tooth with no adhesive at the incisal edge. This composite mock-up should cover partially the facial aspect of the tooth respecting the required restoration thickness to avoid having shade mismatch if the composite is too thin or too thick. The composite mock- 72 up must be polymerized since its shade might change upon polymerization and then hydrated before evaluation. Fig.3: Composite mock-up Another technique for shade selection is button try technique by placing small buttons of composite on labial surface then cure it. Fig. 4: Button try technique for shade selection The following guidelines are followed for shade matching: Teeth and shade guide should be wet to simulate the oral environment. Shade matching should be carried in natural daylight. The dentin shade is usually selected from the cervical third of the tooth, whereas the enamel shade is selected from its incisal third. 73  To confirm the final shade, a small increment of selected composite is placed adjacent to the area to be restored and then light cured for matching. 5. Isolation To achieve the optimal results of composite restoration, moisture control and salivary contamination must be prevented, in other words isolation is must. Contamination of etched enamel or dentin by saliva results in a decreased bond strength and contamination of the composite material during insertion results in degradation of its physical properties. Isolation is best done by using rubber dam, though it can be done using cotton rolls, saliva ejector and retraction cord. Fig. 5: Rubber dam and cotton roll isolation 74  6. Tooth Preparation Following features are to be kept in mind while doing tooth preparation for direct composite restorations. Tooth preparation is limited to extent of the defect, that is extension for prevention, including proximal contact clearance, is not necessary unless it is required to facilitate proximal matrix placement. To facilitate bonding, tooth surface is made rough using diamond abrasives. Pulpal and axial walls need not to be flat. Enamel bevel is given in some cases to increase the surface area for etching and bonding. Cavosurfaces present on root surfaces are made with butt joint. Designs of Tooth Preparation for Composites The following three types of design or their combination are mostly prepared for composites: 1. Conventional 2. Beveled conventional 3. Modified (conservative). 1. Conventional: Conventional design is similar to the tooth preparation for amalgam restoration, except that there is less outline extension and in tooth preparation, walls are made rough. Indications for conventional tooth preparation Preparations located on root surface. Moderate to large class I or class II restorations. Prepared enamel margins should be 90 degree or greater. Buttjoint cavosurface margin is made on root surfaces. The prepared tooth surface is roughened to increase the bonding. 75  Fig. 6: Conventional class IV cavity 2. Beveled conventional tooth preparation: This design is almost similar to conventional design but some beveled enamel margins are incorporated. Indications When restoration is being used to replace an existing restoration exhibiting a conventional design. To restore a large preparation and specially indicated for classes III, IV, V and VI restorations. Fig.7: Conventional with bevel class IV cavity 76 3. Modified (conservative tooth preparation): It is more conservative in nature since retention is achieved by micromechanical bonding to the tooth. Indications: For initial or small carious lesions. Features Preparation has scooped out appearance. It does not have specified wall configuration or pulpal and axial wall depth. Extent and depth of the preparation depends upon the extent and the depth of carious lesion. In combination preparations, that is part of the preparation is on crown and part is on root, the root surface is prepared as conventional preparation and enamel surface portion is prepared as beveled conventional preparation where enamel margin is beveled. Fig. 8: Modified class IV cavity 77  7. Bonding Adhesive placement steps are accomplished with strict adherence to the manufacturer’s directions for the particular bonding system being used. Adhesion of composites to tooth structure can be attained with any of following methods: Fig. 8: Different bonding system 8. Composite Placement Instruments Used for Composite Insertion Following instruments are used for the placement of composites in the prepared tooth. Hand instruments: Hand instruments used for placing composites are usually made up of coating with Teflon so as to avoid sticking of composite to the instrument. These instruments are simple and easy to use but the problem of air trapping during insertion of composite can occur. 78  Fig. 9: Teflon coated instruments used for composite placement Composite gun: Composite gun is made up of plastic. It is commonly used with composite filled ampules. For use composite compules are fitted in the gun and the pressure is applied so that composite comes out from the ampule. Fig. 10: Composite gun used for composite compules 79 Syringe: Composite syringe usually carries the low viscosity composite which can easily flow through needle. This technique has advantage of providing an easy way for placement of composite with decreased chances of air trapping. Irrespective of the location of the restoration, composites should be placed and polymerized in increments. This ensures complete polymerization of the whole composite mass and aids in the anatomical buildup of the restoration. Each increment should not be more than 2 mm in thickness, thickness of more than 2 mm is difficult to cure and result in more polymerization shrinkage stress. Fig. 11: Flowable composite in a syringe Matrix Application The polyester strip matrix can be used for most Class IV preparations, although the strip’s flexibility makes control of the matrix difficult. This difficulty may result in an overcontoured or undercontoured restoration or open contact or both. Also, composite material extrudes incisally, but this excess can be easily removed when contouring and finishing. Creasing (folding) the matrix at the position of the lingual line angle helps reduce the potential under contouring (rounding) of that area of the restoration. The matrix is positioned and wedged. Gingival overhangs and 80 open contacts are common with any matrix techniques that do not employ gingival wedging. A commercially available preformed plastic or celluloid crown form is usually too thick and is not recommended as a matrix. If the operator does not have sufficient experience in using the more flexible polyester strip matrix, a custom lingual matrix may be used for large Class IV preparations. Fig. 12: Mylar strip and Palatal index Inserting and Curing the Composite. After the bonding adhesive has been applied and cured, the operator inserts the composite and cures in 1- to 2-mm increments to ensure complete polymerization and possibly to reduce the effects of polymerization shrinkage. Insertion is best accomplished with a hand instrument, although a syringe can be used. Because light-cured composites possess the advantage of an extended working time, the material can be manipulated and shaped to a considerable degree before curing. Incremental insertion and curing of light-cured composites also enable the clinician to layer composites with different optical properties (more opaque and darker in color to mimic the dentin and more translucent and 81 lighter in color to mimic the enamel), which can result in lifelike composite restorations. After polymerization, the lingual matrix is removed. To ensure optimal polymerization, the operator cures the restoration from facial and lingual directions. 9. Contouring and Polishing the Composite Restoration The objective of finishing is to contour the composite restoration to its final shape. This process leaves a surface that is still rough and requires polishing to achieve a smooth clinically optimal surface while enhancing the final esthetics and comfort of the restoration for the patient Importance of finishing and polishing: 1. It ensures the oral health and longevity of restorations. smooth surface reduces the likelihood of adhesion, which means plaque is less likely to accumulate on a polished surface. This leads to healthier, longer-lasting restorations. 2. Minimizes gingival irritation and surface discoloration. A polished tooth is more biologically compatible with the gingival tissue, so the health of the gingival tissue is maintained. 3. Improve marginal integrity of the restoration. Interproximal surfaces have the maximum potential for plaque retention and polishing these surfaces will significantly lower patients’ risk for secondary caries and periodontal disease. 4. Create more natural and esthetic smiles. 5. Enhance the longevity, durability, and long-term wear resistance of the restoration. 6. Enhances patient comfort and satisfaction. 82  Technique of Finishing/Polishing Starting with a coarse disc or a finishing bur, the restoration can be completely contoured moving from restorative material to tooth surface, similar to burnishing metal. This can be done in a wet or dry field. The material should be extended well past the long bevel, and the dentist should not come back to the beveled margin. The final restoration should be featheredged onto the tooth surface past the beveled margin. If done properly, any white line or raised margin will completely disappear. At this stage, the disc should be flexed for maximum finishing potential. Fig. 13: Composite finishing Kit 83  Fig. 14: soflex polishing kit The different grit sizes—medium, fine, and superfine—should be continued through in succession. An enamel like luster rapidly appears. The interproximal process should be started with diamond strips to maintain the integrity of the contact. One or two times through the interproximal should be sufficient, followed with the fine, superfine aluminum oxide strip on dry surface until no resistance is felt, and a smooth surface is apparent. 84  A full case step by step class IV composite restoration Before restoration. Button try technique To make sure that we choose the All sharp edges were rounded up and right color we always check with 2 mm bevel was placed. For creating VITA shade guide bevel we use a diamond bur with a yellow marker After isolation of adjacent teeth with Right after rinsing of the etching gel. mylar matrix strips (or teflon tape), selective etching technique is used on the enamel for 30 seconds 85  Bonding application Palatal shell restored with the silicone key technique. Final layer of composite Finishing Polishing with a rubber abrasive Polishing is finished with a silicone point abrasive wheel Final view after rehydration 86 Chapter 3  Direct Posterior Resin Composite Restorations "An ounce of performance is worth pounds of promises." Objectives This chapter presents information about typical class I, and II direct composite restorations (Fig.1). The chapter also presents information and techniques for pit-and-fissure sealants, preventive resin or conservative composite restorations. Fig. 1 Composite restorations. A and B, Class I composite, before and after. C and D, Class II composite, before and after Conflicting opinion and a wealth of contradictory data present difficulties for dentists in choosing which materials, instruments and 87 techniques to employ when considering restoration of posterior teeth with direct resin composite. In some areas of the world, resin composite is the first (or only) choice for direct restorations in teeth, with the setting up of ‘amalgam- free’ practices and a dental school which has not taught amalgam placement techniques for over a decade. In this respect, although amalgam has served dentistry for over a century and, if well placed, may provide restorations which function beyond 30 years, encouraging clinical outcomes have caused some clinicians to favour composite, even when restoring large cavities. There has been a consequent decline in the worldwide use of amalgam over the last decade and a concomitant increase in the use of resin composite. This situation has been brought about by: Alleged health concerns and environmental considerations regarding amalgam. The dental profession’s desire for an adhesive material that demands less invasive cavity preparations. Patient demand for tooth-colored restorations in posterior teeth. With good case selection, proper adhesion and placement, posterior resin composites can provide successful and predictable restorations that may match the appearance of natural teeth. American Dental Association stated that “when used correctly in the permanent dentition, the expected lifetime of resin-based composites can be comparable to that of amalgam in class I, and class II restorations.” However, if composite is to compete 88 truly in terms of prognosis and longevity, material performance, adhesion and restorative techniques must be optimized. Indications Class I and II direct composite restorations are indicated for: Restoration of primary caries lesions in the occlusal and proximal surfaces of posterior teeth. Replacement of old or failed amalgam restorations in posterior teeth. These restorations are particularly indicated when esthetics is considered to be of primary importance. They also are indicated occasionally as large restorations that may serve as foundations for crowns. In selected cases, large composite restorations may be used where an interim restoration is indicated or where economics or other factors preclude a more definitive restoration such as indirect esthetic restorations. Contraindications The main contraindication for use of composite for class I and II restorations is an operating area that cannot be adequately isolated. Class I and II composites also may be contraindicated for large restorations when heavy occlusal stresses are present. 89  In restorations in which the proximal box extends onto the root surface, posterior composites should only be used if absolutely required because of the difficulty in predictably bonding to the gingival wall with no enamel margin. Advantages The advantages of composite as a class I and II direct restorative material relative to other restorative materials are: Esthetics Conservative tooth structure removal Easier and less complex tooth preparation Thermal insulation Decreased microleakage Increased strength of remaining tooth structure. Disadvantages The disadvantages of class I and II direct composite restorations are as follows: Polymerization shrinkage effects Lower fracture toughness than most indirect restorations More technique-sensitive than amalgam restorations and some indirect restorations 90  Possible greater localized occlusal wear Unknown biocompatibility of some components Pits-and-Fissure Sealants Concept Pits and fissures typically result from an incomplete coalescence of enamel and are particularly prone to caries. These areas can be sealed with a low-viscosity fluid resin after acid-etching. Long-term clinical studies indicate that pit-and-fissure sealants provide a safe and effective method of preventing caries. Indications Sealants should be used primarily for the prevention of caries rather than for the treatment of existing caries lesions. Only caries-free pits and fissures or incipient lesions in enamel not extending to the dentino-enamel junction (DEJ) currently are recommended for treatment with pit-and-fissure sealant. Clinical Notes o A bitewing radiograph should be obtained and evaluated before sealant placement to ensure that no dentinal or proximal caries is evident. o Explorers must be used judiciously in the detection of caries, as a sharp explorer tine may cause a cavitation. 91  o The clinical examination should be primarily focused on visual assessments of a clean tooth surface, preferably under adequate light and magnification. Advantages They provide an alternative to tooth preparation and restoration techniques for elimination of caries prone pits and fissures on occlusal surfaces. Materials Employed Most currently used sealant materials are: 1) Filled sealants. They are a combination of resins, chemicals, and fillers. The purpose of the filler is to increase bonding strength and resistance to abrasion and wear. 2) Unfilled sealants. They have a higher ratio of resin to filler material, and do not need to be adjusted with a dental handpiece; they are in essence self-occluding. Due to low viscosity of unfilled sealants, they readily flow into the pits and fissures. Mechanism of Action 1) They eliminate the geometry that harbors bacteria and to prevent nutrients reaching bacteria in the base of the pit or fissure. 2) The principal feature of a sealant required for success is adequate retention. The sealant blocks bacterial accumulation occurring in otherwise non self-cleansing locations (Fig.2). Complete penetration 92  of the sealant is not absolutely critical. It is possible to occlude only the neck region of a fissure and produce clinically acceptable results. Clinical Technique The following discussion deals with a fissure present on a mandibular first permanent molar (Fig. 3). Step 1: The tooth is isolated by using a rubber dam (or another effective isolation method such as cotton rolls). Step 2: The area is cleaned with a slurry of pumice on a bristle brush. Step 3: The tooth surface is dried, and etched with 37% phosphoric acid gel for 15-30 seconds Step 4: The sealant material is then applied with an applicator or small hand instrument. The sealant is gently teased into place, to avoid entrapping air, and it should overfill slightly all pits and fissures, but it should not extend onto unetched surfaces. Step 5: The sealant is light-activated for 15 seconds. Step 6: The occlusion is evaluated by using articulating paper. 93  Fig. 2 Pit and fissure before and after sealing Fig. 3 Stops in application of pit-and-fissure sealant. A, after isolation and thorough cleaning of the occlusal surface to be sealed. B, after acid-etching, rinsing, and drying. C, with sealant applied. 94 Clinical Notes If too much sealant is applied, excess can be removed with a microbrush prior to light-activation. If necessary, a round carbide finishing bur or white stone is used to remove any excess sealant. The surface usually does not require further polishing. 95  Preventive Resin and Conservative Composite Restorations Definition The ultraconservative preparation design of minimal removal of the tooth structure combined with the use of flowable composite or sealant to seal radiating noncarious or carious fissures and pits is known as preventive resin restoration, or conservative composite restoration (Fig. 4). Indications 1) This procedure is useful if a definitive diagnosis of caries cannot be made. 2) Conservative composite restoration is the treatment of choice for the primary occlusal caries lesion with minimal dentinal depth as the tooth preparation can be minimally invasive. Clinical Technique Step 1: The exploratory preparation of the suspicious area is performed with a small bur or diamond (Fig. 5) and an assessment is made in the suspicious areas to determine whether or not to continue the preparation toward the DE] (see Fig. 5). Step 2: If the suspicious fault is removed or found to be sound at a shallow preparation depth (minimal dentin caries), the conservative exploratory preparation and adjacent pits and fissures are etched with 37% phosphoric acid for 15-30 seconds, rinsed, and lightly dried. 96 Fig.4 Conservative composite restoration. A, Occlusal view of the maxillary first and second molars. The first molar has caries on the distal occlusal pit, and the second molar has suspicious pit on the disto- occlusal aspect. B, Caries was excavated from the first molar, and the second molar was minimally prepared. C, The first molar was restored with composite, and the second molar received a conservative composite restoration with flowable composite. 97 Step 3: The etched surfaces then are treated with an adhesive, which is placed and light-activated, according to manufacturer’s instructions. Step 4: The conservatively prepared area can then be restored with a flowable composite, which is placed and light-activated, according to manufacturer’s instructions. Step 5: The adjacent etched pits and fissures, if judged to be at risk, can then be sealed using a pit- and-fissure sealant or the same flowable composite following the technique described previously 98 Fig. 5 Class I direct composite restoration and conservative composite restoration. A, Mandibular second molar with suspicious occlusal pits; mandibular first molar with questionable sealant. B, After rubber dam isolation. C, Initial exploratory preparation reveals caries extending toward the dentinoenamel junction (DEJ). D, Conservative preparation on the second molar; the first molar was minimally prepared. E, Complete class I direct composite restoration on the second molar; the first molar received a conservative composite restoration with flowable composite. F, Final restorations after the rubber dam was removed and the occlusion was checked. Clinical Notes If the suspicious area is found to be carious, the preparation depth is extended until all of the caries is removed, and the prepared area is then restored with composite as described later in this chapter (class I direct composite restoration), and unprepared pits and fissures are sealed Clinical Technique for Direct Class I Composite Restorations Initial Clinical Procedures The initial clinical procedures include anesthesia, shade selection, occlusal relationship, and isolation of the operating field. These are necessary before beginning a class I composite restoration. Cavity Preparation As a general rule, similar to the cavity preparation for direct anterior restorations, the cavity preparation for direct posterior composites involves: Creating access to the faulty structure 99  Removal of faulty structures (caries, defective restoration and base material, if present) Creating convenience form for the restoration I. Small to Moderate Class I Composite Restorations Cavity Design These preparations are less specific in form, having a scooped-out appearance without uniform or flat pulpal or axial walls. Clinical Technique Small to moderate class I direct composite restorations may use minimally invasive tooth preparations and do not require typical resistance and retention form features. They are prepared with a small round or elongated pear diamond instruments. The initial pulpal depth is approximately 0.2 mm inside the DEJ. If a round instrument is used, the resulting cavosurface margin angle may be more flared (obtuse) than if an elongated pear instrument is used (Fig. 6). 100. Fig. 6 Faciolingual cross-section of small class I tooth preparation using round diamond. Clinical Notes The size and shape of the rotary instrument is dictated by the size of the lesion or other defect or by the type of defective restoration being replaced. Both carbide and diamond instruments can be used effectively. It should be noted that diamond instruments create a thicker smear layer, however, which might make bonding more difficult for self-etch bonding systems II. Moderate to large Class I Direct Composite Restorations Moderate to large Class I direct composite restorations, especially when used for larger caries lesions or to replace existing defective amalgam restorations, will typically feature flat walls that are 101 perpendicular to occlusal forces, as well as strong tooth and restoration marginal configurations. All of these features help resist potential fracture in less conserv