Operative Dentistry: Diagnosis, Treatment, and Prevention PDF

**OPERATIVE DENTISTRY** **INTRODUCTION TO OPERATIVE DENTISTRY** - The art and science of dentistry which deals with **diagnosis**, **treatment**, and **prognosis** of defects of the teeth that [do not] require [full coverage restorations] for correction **INDICATIONS OF OPERATIVE DE...

**OPERATIVE DENTISTRY** **INTRODUCTION TO OPERATIVE DENTISTRY** - The art and science of dentistry which deals with **diagnosis**, **treatment**, and **prognosis** of defects of the teeth that [do not] require [full coverage restorations] for correction **INDICATIONS OF OPERATIVE DENTISTRY** 1. **Dental Caries** - Is an infectious microbiological disease of the teeth which results in localized dissolution and destruction of the **calcified tissue**, caused by the action of **microorganisms** and fermentable **carbohydrates** - Three important factors in the formation of dental caries - Calcified tissue - Microorganisms - Carbohydrates - "Gangrene-like" disease 2. **Loss of tooth structure due to attrition, abrasion, abfraction, and erosion** - Attrition - Is mechanical wear of the incisal or occlusal surface as a result of functional or parafunctional movement of the mandible (tooth-to-tooth contact) - Abrasion - Is abnormal tooth surface loss resulting from direct friction forces between the teeth and external objects, or from frictional forces between contacting teeth components in the presence of an abrasive medium - Erosion - Is the wear or loss of tooth surface through chemicomechanical action - Abfraction - Cervical, wedge-shaped defects caused by strong, heavy, eccentric occlusal forces resulting in microfractures or abfractures 3. **Malformed, traumatized, or fractured teeth** - Traumatic injuries may involve the hard dental tissues and the pulp which require restoration - Sometimes, teeth do not develop normally and there are number of defects in histology or shape which occur during development and become apparent on eruption - Malformations: - **Nonhereditary enamel hypoplasia** occurs when the ameloblasts are injured during enamel formation; results in defective enamel (diminished form or calcification); usually seen on anterior teeth and firstmolars in the form of opaque white or light brown areas with smooth intact, hard surface; or of pitted or grooved enamel, which is usually hard and discolored and caused by fluorosis or high fever - **Amelogenesis imperfecta** -- the enamel is defective either in form or calcification as a result of heredity and has an appearance ranging from essentially normal to extremely unsightly - **Dentinogenesis imperfecta** -- a hereditary condition in which only the dentin is defective. Normal enamel is weakly attached and lost early - Fractures: - **Incomplete fracture not directly involving vital pulp** **(enamel-dentin fracture)** -- an incomplete fracture not directly involving a vital pulp is often termed a [greenstick fracture] - **Complete fracture not involving vital pulp** -- usually, pain is not associated with this condition, unless the gingival border of the fractured segment is still held by periodontal tissue - **Fracture involving vital pulp** -- this condition always results in pulpal infection and severe pain 4. **Esthetic improvement** - Discolored teeth because of staining or other reasons look unesthetic and require restoration - Laminates, veneers, bleaching, etc. 5. **Replacement or repair of restoration** **Treatments of operative dentistry would result to:** - restoration of proper tooth **form** - proper **functions** - **esthetics** **HISTORY OF OPERATIVE DENTISTRY** - 1840 -- Baltimore College of Dental Surgery - Marked the official birth of formal dental education as a discipline - 1867 -- Harvard University established the first university-affiliated dental program - Greene Vardiman Black - Father of Modern Operative Dentistry - Established the principles of cavity preparation - classified caries and set-up nomenclature - dealt also with staining problems produced by oral bacteria - wrote about dental caries, erosion, and oral pathology - Formulated the first amalgam alloy - Louise Pasteur - Discovered the role of microorganisms in disease - Arthur Black - Expanded the scientific foundation of operative dentistry - Introduced instruments and techniques advocated by his father GV Black - Robert Barnum - Invented the first rubber dam - 1999 - Periodic examination, bite wing radiograph and prophylactic procedure became the most common procedure in dentistry **GOALS OF OPERATIVE DENTISTRY** 1. **Diagnosis --** the determination of nature of disease, injury, or other defect by examination, test, and investigation 2. **Prevention** - to prevent any occurrence or recurrence of the causative disease and their defect - the primary goal of caries prevention program should be to reduce the numbers of cariogenic bacteria - limit pathogen growth and metabolism - increase the resistance of tooth surface to demineralization - examples: - fluoride application (varnish, supplements) - pit and fissure sealants - dietary and nutrition counseling - dental hygiene - methods of preventive measures: - limit substrate -- reduce number, duration, and intensity of acid attacks; - eliminate or substantially reduce sucrose from between meal snacks - stimulate saliva flow -- increase clearance of substrate and acids; promote buffering; - eat non-cariogenic foods that require lots of chewing - plaque disruption -- prevents plaque succession; decreases plaque mass; promotes buffering - brushing - flossing, etc. - modify microflora -- intensive antimicrobial treatment to eliminate MS from mouth - bacterial mouthrinse - topical fluoride treatments - antibiotic treatments - modify tooth surface -- increase resistance to demineralization; decrease plaque retention - systemic fluorides - topical fluorides - smooth surface - Restore tooth surfaces -- eliminate nidus of MS and lactobacillus infection; deny habitat for MS for reinfection - Restore all cavitated lesions - Seal pits and fissures at caries risk - Correct all defects 3. **Interception --** preventing further loss of tooth structure by stabilizing an active disease process - Changes in patient's home care procedure - Removal of carious tooth tissue - Altering tooth form through restoration or selective contouring - Enhancing occlusal stability 4. **Preservation --** preservation of the vitality and periodontal support of remaining tooth structure through prevention and interceptive measures - instrumentation approach to removal of carious tissues and cavity design seeks to retain uninvolved sound tooth tissue and to maintain pulp vitality as well as the health of the supporting tissues 5. **Restoration** -- includes restoring form, function, phonetics, and esthetics - Root canal, Post and core, crown restoration - Composite resin filling, inlay, onlay 6. **Maintenance --** maintain the restoration, preservation, prevention, interception, of the involved tooth - Recall visits **REVIEW OF CARIOLOGY** **Dental caries** - An **irreversible** microbial disease of the calcified tissues of the teeth that is characterized by the demineralization of the inorganic portion and destruction of the organic substance of the tooth, which often leads to cavitation (Shafer, 1993) - An infectious microbiologic disease of the teeth that results in localized dissolution and destruction of the calcified tissues (Sturdevant, 2012) - A biofilm-mediated, sugar-driven, multifactorial, dynamic disease that results in the phasic demineralization and remineralization of dental hard tissues (Nature Reviews Dental Primers, 2017) - The balance between pathologic and protective factors influences the initiation and progression of caries - Biofilm-mediated, diet modulated, multifactorial, non-communicable, dynamic disease resulting in net mineral loss of dental hard tissues (ORCA, IADR, 2020) **Etiology of Dental Caries** 1. **Host** - Susceptible tooth surface - Oral fluids - Genes 2. **Bacterial biofilm** - microorganisms 3. **Time** - Significant length of time for the 3 factors to interact 4. **Sugar substrate** - Cariogenicity of consumed carbohydrates - Oral clearance - Eating frequency **Cariogenicity potential --** the degree to which a tooth is likely to become carious **HYPOTHESES CONCERNING ETIOLOGY OF CARIES** 1. **Non-Specific plaque hypothesis** -- all plaque are pathogenic 2. **Specific plaque hypothesis --** plaque is pathogenic only if associated with clinical disease - Walter Loesche -- "the goal of therapy is to suppress the cariogenic plaques and to replace them with pathogen-free plaques" 3. **Ecological plaque hypothesis** - a certain change in the environment of the residential plaque flora provides pathogenicity to specific species that produce the disease only at specific sites 4. **Extended ecological plaque hypothesis** - The significance of this model is that it is not the bacterial genotype, but the phenotypic characteristics (acidogenic and aciduric) and their regulatory parameters that are more relevant for causing a microbial ecological shift leading to caries **THEORIES OF DENTAL CARIES** 1. **Acidogenic** - By WD Miller - Dental decay is a chemicoparasitic theory consisting of: - Decalcification of enamel - Dissolution of the softened residue of the enamel and dentin 2. **Proteolytic** - Proposed by Gottlieb, by Heider, Bodecker, and Abbott - Organic portion of tooth plays an important role in the development of dental caries - Microorganisms invade the enamel lamellae and causes damage to the organic pathways 3. **Proteolytic-chelation** - By Schatz - Bacterial attack is initiated by keratinolytic microorganisms - Chelation -- negatively charged chelating agent releases positively charged calcium ions from enamel and dentin **PATHOGENESIS OF DENTAL CARIES** **Demineralization** -- when sugar and other fermentable carbohydrates reaches the bacteria, they form acids which start to dissolve the enamel -- an early carious lesion occurs due to loss of calcium and phosphates **Remineralization** -- when sugar consumption has ceased, saliva can wash away sugars and buffer the acids. Calcium and phosphates can again enter the tooth. The process is strongly facilitated by fluorides **\***demineralization\>remineralization = dental caries **CLASSIFICATION OF DENTAL CARIES** (complete) 1. **According to anatomical site or location** - **Pit and fissure caries** - Occurs on occlusal surface of posterior teeth and buccal and lingual surface of molars and lingual surface of maxillary incisors - **Smooth surface caries** - Occurs on gingival third of buccal and lingual surfaces and on proximal surfaces - **Root Caries** 2. **According to whether it is a new lesion or recurrent carious lesion** - **Primary caries** - Present on unrestored surfaces - **Secondary caries** - Occurs at the junction of a restoration and the tooth and may progress under the restoration - **Residual caries** - Left either intentionally or accidentally during cavity preparation 3. **According to activity of carious lesion** - **Active --** carious lesions that are progressive; activity is abrupt - **Inactive --** runs a short course; also known as arrested carious lesion 4. **According to the speed of caries progression/rapidity of progress** - **Acute (rampant) caries --** has a very rapid clinical course; easily attacks the tooth; common among young adults and children; painful - **Chronic (slow)/arrested caries --** runs a longer clinical course; less painful; shows no sign of further progress 5. **According to pathway of caries spread** - **Backward caries** -- caries spread is wider in dentin than enamel - **Forward caries --** caries spread is wider in enamel than dentin; or the same size 6. **According to extent of caries/severity** - **Incipient caries (reversible) --** white spot lesion; first clinical sign of caries; involves less than half thickness of enamel - **Cavitated caries (non-reversible)** - Moderate -- involves more than half of enamel - Advanced -- involves DEJ and less than half of dentin - Severe -- involves more than have of dentin 7. **According to radiograph** - **E0** -- no visible radiographic lesion - **E1 --** lesion in outer half of enamel - **E2 --** lesion in inner half of enamel - **D1 --** lesion in outer third of dentin - **D2 --** lesion in middle third of dentin - **D3 --** lesion in inner third of dentin 8. **According to number of tooth surfaces involved** - Simple caries -- involves only one tooth surface - Compound caries -- if two surfaces are involved - Complex caries -- if more than two surfaces are involved 9. **According to GV Black** - Class I -- pits and fissures of premolars and molars; lingual surface of incisors - Class II -- proximal surface of premolars and molars - Class III -- proximal surface of anterior teeth without incisal angle - Class IV -- proximal surface of anterior teeth with incisal angle - Class V -- gingival third of facial and lingual surfaces of the teeth - Class VI -- incisal edges of anterior and cusp tips of posterior without involving any other surface 10. **According to ICDAS** **Full ICDAS** 0 **--** no evidence of caries 1 -- initial caries 2 -- distinct visual change in enamel 3 -- localized enamel breakdown 4 -- underlying dark shadow from dentine 5 -- distinct cavity with visible dentine 6 -- extensive distinct cavity with visible dentine **Modified ICDAS** 0 - no evidence of caries A - initial caries 3 -- localized enamel breakdown 4 -- underlying dark shadow from dentine 5 -- distinct cavity with visible dentine 6 -- extensive distinct cavity with visible dentine **Merged ICDAS** 0 - no evidence of caries A - initial caries B -- moderate caries C -- extensive caries **PRINCIPLES OF CAVITY PREPARATION (GV BLACK)** 1. **Outline form --** the shape or form of the cavity on the surface of the tooth 2. **Resistance form --** the shape given to the preparation that enables the restoration and the remaining tooth structure to withstand masticatory forces 3. **Retention form --** the shape of the internal aspect of a prepared cavity to prevent displacement of the restorative material 4. **Convenience form --** the shape or form of the cavity that allows adequate vision, accessibility, and ease of instrumentation during cavity preparation as well as insertion of the restorative material 5. **Removal of remaining carious dentin --** the mechanical elimination of carious dentin and debris from cavity preparations - Affected dentin (zones 2 and 3) - Does not contain microorganism - Can be remineralized by restorative means - Accepted to allow to remain in prepared tooth - Infected dentin (zones 4 and 5) - Contains microorganisms - Cannot be remineralized by restorative means - Should be removed during cavity preparation 6. **Finishing of the cavity walls --** involves refining of certain areas of the cavity wall: - Dentin portion - Enamel portion - Cavosurface margin 7. **Toilet of the cavity** - freeing the preparation walls and margins from objects that may interfere with proper adaptability of the restorative material - drying the preparation walls, floors, and margins - sterilization of preparation walls and floors **DIVISIONS OF RESTORATIVE DENTISTRY** 1. **Examination and Diagnosis** **Examination --** process of observing both normal and abnormal conditions of the teeth and the **oral cavity as a whole** in order to arrive at an accurate diagnosis - **Chief Complaint** - - - - **History of Present Illness (HPI)** - - **Clinical Examination** - - - - - **Diagnosis** - determination or identification of the diseased condition based from thorough examination - Precise, scientific terms used to describe variations from normal - this type of diagnosis when the diagnosis is uncertain, but it is prudent to begin some type of treatment - A temporary diagnosis that can be used as a basis for an immediate treatment - General or specific issues that are considered as significant findings - They may affect the treatment plan but does not fit the definition of diagnosis - Pieces of information in the patient's database gathered through scientific procedures i.e., economic status **Prognosis** - Refers to an estimation of the likelihood of a favorable outcome for a disease and is usually expressed in such general terms as "excellent", "good", "favorable", "unfavorable", or "poor" 2. **Prophylactic Procedures --** scaling, polishing, or simply dental cleaning; to facilitate proper charting 3. **Treatment planning/procedures --** sequenced series of services designed to eliminate or control etiological factors, repair existing damages, and create a functional, maintainable environment **Four steps in the development of treatment plan:** 1. Examination and problem identification 2. Decision to recommend intervention 3. Identification of treatment alternatives 4. Selection of the treatment with the patient's involvement **Guidelines for Sequencing Dental Treatment** 1. **Systemic Treatment** -- involves a thorough evaluation of the patient's health history and any procedures necessary to manage the patient's general and psychological health before or during dental treatment; **ex.** Vitamin C for bleeding gums a. Consultation with patient's physician b. Premedication c. Stress/fear management d. Any necessary treatment considerations for systemic disease 2. **Acute treatment** -- the purpose is to resolve any symptomatic problems that a patient may present with; complaints or problems that require attention such as pain, swelling, infection, broken teeth, and missing restoration; **ex.** Composite restoration e. Emergency treatment for pain or infection f. Treatment of the urgent chief complaint when possible 3. **Disease control --** the goal is to control active oral disease and infection, stop occlusal and esthetic deterioration, and manage any risk factors that cause oral problems; includes also oral hygiene instructions, scaling and root planning, caries risk assessment; **ex.** Oral prohpylaxis, oral hygiene instruction, pit and fissure sealants, diet counseling g. Caries removal to determine restorability of questionable teeth h. Extraction of hopeless or problematic teeth i. Periodontal disease control j. Caries control k. Replace defective restoration l. Endodontic therapy for pulpal or periapical pathology m. Stabilization of teeth with temporary or foundation restorations n. Post-treatment assessment 4. **Definitive Treatment** -- aims to rehabilitate the patient's oral condition and includes procedures that improve appearance and function; ex. Fixed bridges, crowns o. Advanced periodontal therapy p. Stabilize occlusion q. Orthodontic, orthognathic surgical treatment r. Occlusal adjustment; TMJ treatment s. Definitive restoration of individual teeth t. Esthetic dentistry u. Elective extraction of asymptomatic teeth v. Prosthodontic replacement of missing teeth w. Post-treatment assessment 5. **Maintenance Therapy --** periodically reevaluate the patient and provide supportive care to prevent relapse and recurrence of disease; Includes periodic examinations, periodontal maintenance treatment, fluoride application, and oral hygiene instructions; check up every 6 months x. Periodic visits  **Pulp Capping** - Performed when there is tooth sensitivity - Calcium hydroxide and glass ionomer cement as base - IRM cement not compatible - **Indirect --** pulp not exposed - **Direct --** pulp exposed **INSTRUMENTATION** **Classification of Dental Instruments:** 1. Examination instruments 2. Scaler instruments 3. Cutting instruments 4. Restorative instruments 5. Accessory instruments **Instrument Sequencing** - Done for a more organized tray set-up - To follow guidelines of treatment plan **Instrument Design** 1. **Single-ended instruments --** only has one working end 2. **Double-ended instruments --** has two working ends **3 parts of Dental Hand Instruments** 1. **Working end** - **Nib --** working end of non-cutting instruments; working surface - **Blade --** working end of cutting instruments 2. **Shank --** where the handle connects with the working end 3. **Handle --** where we grasp our instrument **Numeric Formula of Dental Instruments** - GV Black Developed a system of assigning numeric formula to instruments - Used metric system - For angulations, centigrade are used - **Three-Number Formula** **1^st^ no. --** width of blade in tenths of mm **2^nd^ no. --** length of blade in mm **3^rd^ no. --** angle formed by the blade with the axis of the handle - Used for instruments in which the primary working end is at a right angle to the long axis of the blade **Four-Number Formula (WALA)** **1^st^ no. --** width of blade in tenths of mm **2^nd^ no. --** angle formed by the primary cutting edge with the axis of the handle **3^rd^ no. --** length of the blade in mm **4^th^ no. --** angle formed by the blade with the axis of the handle - Used in instruments in which the cutting edge at the end of the blade is not at a right angle to the long axis of the blade **EXAMINATION INSTRUMENTS** **Mouth Mirror** - Front-surface reflecting mirror -- coating is present in the front surface of the mirror to prevent image distortion - Rear-surface reflecting mirror -- most commonly used; coating is present on the backside of the mirror - Plane/flat surface mirror -- provides clearer image without distortion - Concave surface mirror -- provides different degrees of magnification; image somewhat distorted - **Functions:** - **Explorer** - for caries and calculus detection, exploration of pocket characteristics, furcations, and restorations **Excavator** - for removal of carious dentin **Cotton plier** - used to grasp or transfer materials in and out of the oral cavity - may be locking or non-locking **Periodontal Probe** - to assess periodontal pocket depths, attachment levels, anatomy configurations, and gingival bleeding - used in assessing depth of cavity preparations **BASIC TRAY SETUP** - mouth mirror - explorer - cotton plier - periodontal probe - scalers, accessory instruments (for particular procedures)  **SCALER INSTRUMENTS** - used for removing supra- and subgingival calculus and other deposits from teeth. They are also useful for removing temporary crowns - used in scaling, root planing, oral prophylaxis **Universal Scalers --** are designed primarily for the removal of subgingival calcular deposits on all tooth surfaces **Sickle Scalers --** are heavy instruments used to remove supragingival calculus  **Curette --** used for removing deep subgingival calculus, root planing altered cementum, and removing soft tissue lining the periodontal pocket **Files --** used to fracture or crush large deposits of tenacious calculus  **CUTTING INSTRUMENTS** **Four subdivisions of Excavators:** 1. Ordinary hatchets 2. Hoes 3. Angle formers 4. Spoon Excavators **Different angulations:** 1. Binangle spoon excavator -- double angulation 2. Triple-angle spoon excavator  **Spoon Excavator** - used for removing softened dentine and temporary fillings - The back of the blade can also be used for placing linings - they are sometimes used for carving amalgam - They have a discoid or ovoid blade, the margin of which is beveled to a sharp cutting edge **Chisel** - **Straight chisel --** primarily intended for cutting enamel. Its primary edge is perpendicular to the long axis of the handle - **Wedelstaedt chisels --** have the primary cutting edges in a plane perpendicular to the axis of the handle and may have either distal or mesial bevel. Used to plane enamel walls  **Hatchet** - the blade and the cutting edge are on a plane with the long axis of the handle - shank with 1 or more angles - the face of the blade is directed to the left or the right - used for cutting enamel **Hoe** - has a cutting edge that is at a right angle to the handle - Used for planing tooth preparation walls and forming internal line angles - For class III and V preparations for direct gold restorations  **Gingival Margin Trimmers** - Similar to hatchet however the blade is curve, and the bevel for the cutting edge at the end of the blade is always on the outside curve - Used to produce a proper bevel on gingival enamel margins of proximoocclusal preparations **RESTORATIVE INSTRUMENTS** - Facilitates placement of filling materials **Amalgam Carrier** - Carries properly mixed amalgam into the cavity preparation  **Condensers and Pluggers** - Used for compressing and forming filling materials, particularly amalgam - They are used with heavy pressure - Variety of shapes and sizes and the end may be smooth or indented **Universal Hobson Plugger** - Used to plug amalgam filling  **Mortonson-Clevedent Plugger** - Used to plug amalgam filling **Burnishers** - Used to condense the filling material properly onto prepared cavity and remove excess filling material - T-ball, football, egg, acorn - - - -  **Cleoid and Discoid Carvers** - Used primarily for carving occlusal anatomy in unset amalgam restorations - Also used to trim or burnish inlay-onlay margins **\ ** **Hollenback Carver** - To enhance occlusal anatomy  **Thin Teflon-coated/titanium nitride instruments** - Used for placing and shaping composite - The surface of the instrument is very hard and is not scratched by the composite filler particles - It also resists the composite sticking to it - Prevents discoloration of filling **ACCESSORY INSTRUMENTS** **Dappen dish -** Serves as a canister for cements or other materials  **Amalgam well --** where properly mixed amalgam is placed before placing in the cavity **Scissors**  **Mercury dispenser** **Mortar and Pestle --** where we triturate amalgam alloy and mercury  **Tofflemire, matrix band, wedge --** used in cases with proximal involvement **Celluloid strips --** used in cases with proximal involvement; to properly fill proximal surface and have good contour  **Sectional Matrix System** **Disposable Microbrush/Applicator brush** - To apply liners, cavity varnishes, bonding agents, etchants **Dycal Applicator** - To apply medicaments, dycal, calcium hydroxide, GIC, IRM, ZOE **Glass slab and Spatula** - Used in mixing cements  **Miller's articulating paper holder** - Used in holding the articulating paper to check patient's bite  **Curing light --** used to polymerize composite restoration **Rubber Dam --** used to isolate a tooth or teeth  **ROTARY CUTTING INSTRUMENTS** **Low-speed handpieces:** **Contra-angle handpiece --** used almost exclusively in the mouth **Straight handpiece --** used for trimming temporary crowns or for carrying out other similar procedures outside the mouth  **Disposable prophy cup and brush** - Utilized in oral prophylaxis **High-speed handpiece --** used when performing tooth preparations  **Ultrasonic and Sonic instruments** -- used for scaling and cleansing tooth surfaces and curetting soft tissue wall of the periodontal pocket **Air abrasion handpiece --** helpful for stain removal, debriding pits and fissures before sealing and micromechanical roughening of surfaces to be bonded  **BUR PARTS AND TYPES OF SHANK** Friction type -- with a separate bur changer; in the older type of air turbine Latch type -- in the contra-angle low-speed handpiece Quick-release clamping chuck -- in the straight handpiece and now in most contra-angle, low-speed handpieces and air turbines **Friction grip burs** 1. Tungsten carbide burs 2. Diamond burs 3. Special metal cutting burs with fine cross-cuts on the cutting blades  **Steel Latch burs** **ROTARY INSTRUMENTS IN CAVITY PREPARATION** **Round burs** - Comes in ¼, ½, 1-8, 10 sizes - Spherical in shape - Uses: - - - - **Inverted cone bur** - Comes in 33 ½, 34-39, 36L, 37L sizes - Provides undercuts for retention  **Straight fissure plain cut bur** - Sizes: 55-60, 57L, 58L - Uses: - - **Straight Fissure cross cut bur** - Sizes: 556-560, 567L, 568L - Helps in forming the internal walls of the preparation  **Tapered Fissure plain cut bur** - Sizes: 169-172, 169L, 170L, 171L - Used for tooth preparations for indirect restorations (mesial and distal aspects) **Finishing Instruments for Amalgam** Plain-cut plain steel finishing burs -- to properly incorporate carvings of anatomy Finishing/Polishing stones -- used in low-speed handpieces; to finish and polish restorations - Mounted stones - Rubber points -- can be coarse to fine - Abrasive rubber cup  **Finishing instruments for composite** - Plastic finishing strip - White stones - Finishing diamonds - Sof-lex discs  **HAND INSTRUMENT TECHNIQUES** - Most operative procedures are completed from, at, or near the 12 o'clock position for the operator - Patient is usually in supine and semi-supine position, depending on the procedure **GRASP** - The manner of holding hand instruments - If it is not held properly, it may result in loss of efficiency and accumulation of unnecessary strain on operator **Different types of Grasps** - Pen grasp -- like holding a pen; not usually used - Modified pen grasp -- permits greater delicacy of touch, similar to that of holding a pen - Inverted pen grasp -- same as the modified, however the hand is rotated so the palm faces more toward the operator - Palm and thumb grasp -- similar to holding a knife - Modified palm and thumb grasp **Modified pen grasp** - Similar to that used in holding a pen - Thumb, index, and middle fingers contact the instrument while the tips of the ring and little fingers are placed on the working tooth as a rest - Palm of the hand is facing away from the operator **Inverted pen grasp** - Hand is rotated so that palm faces more toward the operator - It is used mostly for tooth preparations utilizing lingual approach on anterior teeth  **Palm and Thumb grasp** - Handle placed in the palm of the hand and grasped by all the fingers, while thumb is free of the instrument and rest provided by tip of thumb on nearby tooth of same arch or on a firm, stable structure **Modified Palm and Thumb Grasp** - Same as in palm and thumb grasp - Thumb is rested on the tooth being prepared or the adjacent tooth, used universally - Used in maxillary arch and when dentist is operation from rear chair position  **REST** - Used to stabilize the instrument while performing dental procedures - A proper instrument grasp must include a firm rest to steady the hand during operative procedures - Reduces muscle stress and prevent injury due to muscle fatigue - The closer the rest, the more reliable it is - When it is impossible to establish normal finger rests with the hand holding the instrument, instrument control may be gained using forefinger of the opposite hand on the shank of the instrument - **Classifications:** - - **Intraoral finger rest** 1. **Conventional --** finger rest is established on the tooth surface immediately adjacent to the working area 2. **Cross-arch --** finger rest is established on the tooth surfaces on the other side of the same arch  3. **Opposite-arch --** finger rest is established on tooth surfaces on the opposite arch 4. **Finger-on --** finger rest is established on the index finger or thumb of the non-operating hand **Extraoral Fulcrum Rest** 1. **Palm-up --** established by resting the backs of the middle and ring fingers on the skin overlying the lateral aspect of the mandible on the ride side of the face 2. **Palm-down --** established by resting the front surfaces of the middle and ring fingers on the skin overlying the lateral aspect of the mandible on the left side of the face **GUARD** - Hand instruments or other items, such as interproximal wedges - Used to protect soft tissue from contact with sharp cutting or abrasive instruments - Used to avoid accident of slipping and prevent injuries - It may be mouth mirror, interproximal wedges, cheek retractor, lip retractor, clamps, or even the operators own finger from the other hand **SHARPENING AND CARE OF INSTRUMENTS** **Sharpening:** - Using flat oil stone - Using a mounted stone in a straight handpiece - Using a disc in a straight handpiece **Sterilization:** - All instruments must be cleaned before being sterilized - Stainless steel, tungsten carbide, and Teflon-coated instruments can be autoclaved **Handpiece care:** **Automatic handpiece cleaning unit** - Connected to the air supply - The shield at the front is rotated out of the way and the handpiece plugged onto the connector - A detergent is then flushed through the handpiece followed by oil, both of which come from refillable containers at the back of the unit  **Aerosol Lubricant** - Used for low-speed handpiece - Different adaptors for the nozzle of the aerosol are available for each type of handpiece - The paper towel is used to absorb excess lubricant coming through the head of the handpiece **Burs and Stones/Points Care:** - All burs and stones used in the mouth must be autoclaved - Steel burs are increasingly being regarded as disposable flexible discs and strips are disposable - Tungsten carbide burs become blunt - Diamond burs become clogged or the diamond particles become lost or worn; should be assessed regularly and discarded when they have completed their useful life - Tungsten carbide burs occasionally break in use and diamond burs become bent; a bent bur should always be discarded immediately **CLASS I CAVITY PREPARATION FOR AMALGAM RESTORATION** **Initial tooth preparation stage** 1\. Outline form and initial depth - 1-1.5mm 2\. Primary resistance form - 1.5mm, 0.5mm for finishing 3\. Primary retention form 4\. Convenience form **Final tooth preparation stage** 5\. Removal of any remaining infected dentin and or old restorative material, if indicated 6\. Pulp protection, if indicated 7\. Secondary resistance and retention forms 8\. Procedures for finishing external walls 9\. Final procedures: cleaning, inspecting, sealing **Tray set-up** 1. 4 basic instruments 2. Cutting instruments 3. Highspeed handpiece 4. Burs 5. Phantom jaw / typodont **PRINCIPLES OF CLASS I CAVITY PREPARATION** **OUTLINE FORM** - the shape of the area of the tooth surface included within the cavosurface margins of the prepared cavity - **External outline form** - defined extents of the periphery of the cavity - **Internal outline form** - inner dimensions and relationships of cavity walls Must include: - - - - Features: - Removal of enamel unsupported by dentin - Further extensions for convenience of preparation; extension for prevention - extensions beyond the grooves - Enough width of the isthmus (1-1.5mm); isthmus width = 1/4 intercuspal distance **RESISTANCE FORM** - defined as that shape and placement of the cavity walls that enable both the restoration and tooth to withstand functional forces without fracture **Features:** - Flat pulpal floor - except mandibular first premolar; follows buccolingual/occlusal plane - Maintained perpendicular to the long axis of the tooth - Preservation of the mesial and distal marginal ridges - molars 2mm premolars 1.6mm - Depth of 1.5-2mm; maintained perpendicular to the long axis of the tooth - Mesial and distal wall slightly divergent - prevents fracture of enamel rods, allows proper thickness of restoration **RETENTION FORM** - the shape of the internal aspects of a prepared cavity to prevent displacement of the restorative material **Features:** - Buccal and lingual walls are converging pulpo-occlusally - Dovetails/fishtails - fishtail can only be done on mandibular first molar **FINISHING OF CAVITY WALLS AND MARGINS** - uses hand cutting instruments **Features:** - Gentle curve/no ledges and sharp angles - Smooth margin - Cavosurface margin = 90° (butt joint margin) **GUIDELINES ON PRINCIPLES OF CAVITY PREPARATION (AMALGAM)** **Cavity --** used to describe a carious lesion in a tooth that had progressed to the point that part of the tooth structure had been destroyed **Cavity (tooth) preparation --** the mechanical alteration of a defective, injured, or diseased (carious) tooth to best receive a restorative material that will reestablish a healthy state for the tooth, including esthetic corrections where indicated, along with normal form and function **OBJECTIVES OF CAVITY PREPARATION** 1. Remove all defects and provide necessary protection to the pulp 2. Extend the restoration as conservatively as possible 3. Form the tooth preparation so that under the force of mastication, the tooth or the restoration or both will not fracture and the restoration will not be displaced 4. Allow for the esthetic and functional placement of a restorative material **CAVITY PREPARATION TERMINOLOGIES** **Simple Cavity --** only one tooth surface is involved **Compound cavity --** either joined or not joined 2 surfaces are involved **Complex cavity --** 3 or more surfaces are involved **TOOTH PREPARATION WALLS** **Internal wall --** a prepared (cut) surface that does not extend to the external tooth surface **Axial wall --** an internal wall parallel with the long axis of the tooth **Pulpal wall --** an internal wall that is both perpendicular to the long axis of the tooth and occlusal of the pulp **External wall --** a prepared (cut) surface that extends to the external tooth surface **Floor (seat) --** a prepared (cut) wall that is reasonably flat and perpendicular to those occlusal forces that are directed occlusogingivally **Enamel wall --** the portion of a prepared external wall consisting of enamel **Dentinal wall --** portion of a prepared wall consisting of dentin, in which mechanical retention features may be located **TOOTH PREPARATION ANGLES** **Line angle --** the junction of two planal surfaces of different orientation along a line - **Internal Line angle --** a line angle whose apex points into the tooth - **External Line angle --** a line angle whose apex points away from the tooth **Point angle --** the junction of three planal surfaces of different orientation **Cavosurface angle --** the angle of tooth structure formed by the junction of a prepared (cut) wall and the external surface of the tooth **CLASSIFICATION OF TOOTH PREPARATION (according to shape)** **Conventional Preparations** - Uniform pulpal and/or axial wall depths - Cavosurface margin design that results in a 90-degree restoration margin - Occlusally converging vertical walls for primary retention form - For amalgam restorations **Beveled Conventional preparations** - Conventional preparations with beveling of some accessible enamel margins - For composite restorations **Modified preparations** - Preparations designs may not have uniform axial or pulpal depths or occlusally converging vertical walls **CLASSIFICATION OF TOOTH PREPARATION (according to affected surface)** **Class I --** occlusal surfaces, lingual surface of maxillary incisors **Class II --** proximal surfaces of posterior teeth **Class III --** proximal surfaces of anterior teeth, no incisal angle **Class IV --** proximal surfaces of anterior teeth, with incisal angle **Class V --** gingival third of facial or lingual surfaces of all teeth **Class VI --** incisal edge of anterior teeth or occlusal cusp tip of posterior teeth **STAGES AND STEPS IN TOOTH PREPARATION** **Initial tooth preparation stage** 1\. Outline form and initial depth - 1-1.5mm 2\. Primary resistance form - 1.5mm, 0.5mm for finishing 3\. Primary retention form 4\. Convenience form **Final tooth preparation stage** 5\. Removal of any remaining infected dentin and or old restorative material, if indicated 6\. Pulp protection, if indicated 7\. Secondary resistance and retention forms 8\. Procedures for finishing external walls 9\. Final procedures: cleaning, inspecting, sealing **INITIAL TOOTH PREPARATION STAGE** - The extension and initial design of the external walls of the preparation at a specified, limited depth to: - - - - - **Step 1: Outline form and initial depth** - - - - - - - - - - - - **Step 2: Primary Resistance Form** - - - - - - - - - - - - - - - **Step 3: Primary retention form** - - - - **Step 4: Convenience form** - **FINAL TOOTH PREPARATION STAGE** - **Step 5: Removal of any remaining infected dentin and/or old restorative material (if indicated)** - - **Step 6: Pulp protection (if indicated)** - **CLASSIFICATION OF TOOTH PREPARATION ACCORDING TO REMAINING DENTIN THICKNESS AFTER COMPLETE REMOVAL OF CARIES** **Class A --** minimum depth, but adequate to from a mechanical and biological standpoint - Varnish + amalgam - Etch + bond + composite **Class B --** extends into dentin beyond the minimal depth required by mechanical and biologic factors - IRM or GIC (base)+ varnish + amalgam, - GIC (Base)+ Etch + bond + composite - IRM -- to achieve sedative effect; contraindicated in composite because it inhibits polymerization of composite - GIC -- to apply fluoride and antibacterial of GIC in high-risk patients **Class C --** extends into dentin to such an extent that only a thin but intact wall of dentin remains - CaOH + base + varnish + amalgam - CaOH + GIC + Etch + bond + composite **Class D --** extends into dentin to such an extent that a pulp exposure is actually observed - CaOH + base + varnish + amalgam - CaOH + GIC + etch + bond + composite **Management of caries with pulp exposure**   **Management of moderately deep cavity**  **Management of cavity with ideal floor depth** **Management of Tooth with pulp exposure at the axial wall**   - **Step 7: Secondary resistance and retention form** - - - - - - - - **Step 8: Procedures for finishing the external walls** - - - **Step 9: Final procedures: Cleaning, inspecting, and sealing** - - - **CLASS I CAVITY PREPARATION FOR AMALGAM RESTORATION** ---------------------------------------- ------------------ -------------- **Conventional** **Modified** **Amount of tooth structures removed** More Lesser **Amount of filling material needed** More Lesser **Susceptibility to caries** Lower Higher **Chair time** More Lesser **Cost** Lower Higher ---------------------------------------- ------------------ -------------- **AMALGAM RESTORATION** **Advantages:** - Ease of use - High tensile strength - Excellent wear resistance - Favorable long-term clinical research results - Lower cost than for composite restoration **Disadvantages:** - Non-insulating - Non-esthetic - Less conservative - Weakens tooth structure (unless bonded) - More technique sensitive if bonded - More difficult tooth preparation - Initial marginal leakage **Indications:** - Moderate to large Class I and Class II restoration - Class V restorations (including those that are not esthetically critical, cannot be well isolated, or are located entirely on the root surface) - Temporary caries control restorations (including those teeth that are badly broken down and require subsequent assessment of pulpal health before a definitive restoration) - Foundations e.g., as an abutment for a full crown **Contraindications** - Small to moderate sized lesions - Lesions in the esthetic zone **FRACTURES ENCOUNTERED DURING/AFTER FILLING** **Fracture of the restoration** - Causes: - Not enough depth - No beveling on axiopulpal line angle - Prevention: - Provide enough depth -- 1.5mm - Bevel axiopulpal line angle - Solutions: - Dig-out and trim the cavity preparation **Dislodgement of amalgam** - Causes: - Unable to make retention form - Prevention: - Make retention form (undercut, dovetail, etc.) - Solutions: - Dig out and refill **Overhang** - Causes: - Improper use of matrix band - Failure to use wedge - Prevention: - Always use wedge for class 2 w/ adjacent tooth present - Tighten matrix band - Solutions: - Disk proximal w/ polishing strip or the thinnest proximal bur - Dig out and refill **Pain after placing restoration** - Cause: - Failure to use bases or liners - Underfilled - Prevention: - Prepare materials to be used before starting - Condense well - Solutions: - Dig out and refill **Recurrent caries** - Causes: - Insufficient removal of carious lesion - Unsupported enamel (not removed) - Prevention: - Remove all unsupported enamel - Preparation should terminate on a sound dentin - Solutions: - Dig out, fix preparation, and refill **Fracture of tooth structure** - Causes: - Unbevelled gingival margin - Too much occlusal convergence - Unsupported enamel (not removed) - Prevention: - Remove all unsupported enamel - Follow proper occlusal convergence - Solution: - Dig out, fix preparation, and refill - Crown if too much tooth structure is removed **CLASS II CAVITY PREPARATION** **Occlusal Outline Form (Occlusal Step)** - Initial entry cut is 1.5mm from the central fissure - Pulpal depth is 0.1-0.2mm into dentin - Isthmus width should be ¼ of the intercuspal distance - Dovetail should be 1/3 of the intercuspal distance **Proximal Box Preparation** - Should blend smoothly with the occlusal outline forming one continuous outline - Objectives: - - - **Reverse Curve** - Allows smooth blending of the occlusal and proximal prep - To preserve marginal ridge strength - To increase the bulk of amalgam that will resist the forces of mastication   **PRIMARY RESISTANCE FORM** - Pulpal and gingival walls being relatively flat and perpendicular to forces directed with the long axis of the tooth - Restricting extension of the walls to allow strong cusps and ridge areas to remain with sufficient dentin support - Restricting the occlusal outline form (where possible) to areas receiving minimal occlusal contact - The reverse curve optimizing the strength of both the amalgam and tooth structure at t he junction of the occlusal step and proximal box - Slightly rounding the internal line angles to reduce stress concentration in tooth structure - Providing enough thickness of restorative material to prevent its fracture under mastication  **PRIMARY RETENTION FORM** - Occlusal convergence of facial and lingual walls - By the dovetail design of the occlusal step **FINISHING EXTERNAL WALLS** - Preparation walls and margins should not have unsupported enamel and marginal irregularities - No occlusal cavosurface bevel is indicated in tooth preparation for amalgam - The occlusal line angle may be 90 degrees or butt joint  **TOILET OF THE CAVITY** - Tooth preparation should be free of debris after rinsing the tooth with the air-water syringe - Disinfectants for cleaning tooth preparations **GROSS ERRORS** - Mutilation of adjacent tooth - Unfinished or very wide cavity preparation - Wrong tooth specimen **CLASS III AND V PREPARATION FOR AMALGAM RESTORATION**   **- Class III preparation for amalgam** **CLASS III, IV, and V CAVITY PREPARATION FOR COMPOSITE RESTORATION** **Indications:** - Esthetic prominent areas - Operating area that can be adequately isolated - Technique sensitive **Contraindications:** - An operating area that cannot be adequately isolated - Some Class V restorations in areas that are not esthetically critical - Some restorations that extend onto the root surfaces **CLASSIFICATION OF COMPOSITE CAVITY PREPARATION** 1. **Conventional** - **Indications:** - - **Class III** - - - - **Class IV** - - - - - **Class V** - - - - - 2. **Bevelled Conventional** - **Indications:** - - **Advantages:** - - - - - **Class III** - - - - - - - - - - - - - - **Class IV** - - - - - - - - - - - **Class V** - - - - - - - - - - - 3. **MODIFIED** - **Indications** -  - **Class III** - - - - - - **Class IV** - - - - - - **Class V** - - - **ACID ETCHING** - Produces microporosities or microundercuts - Bonding agent and composite material enters microporosities = more retention