Clinical Operative Dentistry Guidelines PDF

School of Dentistry Department of Dentistry Clinical Operative Dentistry Guidelines January 2021 Kostis Giannakopoulos, DDS, PhD Assist. Prof. Operative Dentistry Course coordinator Anas Salim, DDS, PhD Lecturer, Operative Dentistry Giannis Pl...

School of Dentistry Department of Dentistry Clinical Operative Dentistry Guidelines January 2021 Kostis Giannakopoulos, DDS, PhD Assist. Prof. Operative Dentistry Course coordinator Anas Salim, DDS, PhD Lecturer, Operative Dentistry Giannis Plygkos, DDS, MSc Scientific Collaborator, Operative Dentistry The “Clinical Operative Dentistry Guidelines” is used as a manual for the clinical practice of the dental students at the Department of Dentistry, European University Cyprus. These guidelines are aimed to provide guidance to the dental students to accomplish their clinical practice in Operative Dentistry to the best of their abilities, using evidence based contemporary techniques and dental materials. Furthermore, they are used as a calibration tool between clinical supervisors. The guidelines are complementary to any other theoretical or practical education the students are receiving. 1. Introduction Operative dentistry is the branch of Dentistry that is involved with the study, prevention and treatment of pathological conditions of the hard tissues of teeth that are caused by disease, trauma, wear and/or abnormal development. It is also involved with the conservative esthetic improvement of the smile. The main objective in operative dentistry interventions is to restore natural anatomical form and function, while managing caries by risk assessment, for causative treatment of the disease and not only of the symptoms. Students in operative dentistry are extensively trained to diagnose and treat a variety of simple to complex direct restorative cases while applying preventive measures to minimize new incidents of the disease and improve the overall oral health of their patients. A minimum invasion and conservative surgical approach is always advocated in order to respect the irreplaceable sound tooth structure and increase the overall oral health while decreasing patient discomfort. *Clinical courses in Operative Dentistry (codes, titles, and corresponding year/semester): 1) DES400: Operative Dentistry IV (4th year/7th semester). 2) DES445: Operative Dentistry V (4th year/8th semester). 3) DES500: Operative Dentistry VI (5th year/9th semester). 4) DES555: Operative Dentistry VII (5th year/10th semester). Page 2 of 57 2. Examination of the patient and oral cavity, and caries assessment: In the screening examination all procedures described in the guideline for the new patient initial examination should be followed, including caries risk assessment. In case a comprehensive caries management and prevention plan is needed, it will be completed in a subsequent visit with one of the Operative Dentistry supervisors. According to the supervisor instructions the treatment planning must be completed and consent should be obtained before proceeding to treatment. In many cases, clinical photography is also useful, especially if the case requires advanced or multi-disciplinary treatment planning. In case of emergencies, the proper protocol should be followed. Always, before every Operative Dentistry appointment, the patient’s dental records, treatment plan, and radiographs should be reviewed prior to any treatment. Furthermore, ergonomics (sitting position, dental chair position, and operating position) are required to perform smooth and successful restorative procedure and several factors related to the patient, tooth anatomy, operative procedure, the defective site, and the restorative materials, must be considered. a) Factors related to the patient: (Desires; home; risk status; age; cooperation; anaesthesia). b) Factors related to the tooth anatomy: (Enamel rod orientation; dentin thickness; location of pulp; coronal contours; extent of previous restoration). c) Factors related to the operative procedure: (Operator skills; instrumental design; type of rotary cutting instrument; ability to isolate). d) Factors related to the lesion/defect: (Bone support; occlusion; severity; gingival status; pulpal status; development of fracture). e) Factors related to the restorative material: (Physical properties; colour characteristics). Examination of the aesthetic appearance: In operative dentistry, proper extraoral and intraoral examination of tooth color, form, position, dimensions, Page 3 of 57 display, relation to adjacent teeth, relation to the lips and face is performed before starting any procedure. Examination of occlusion: Proper and careful examination of the patient’s current occlusal characteristics, along with possible impact on masticatory muscles and TMJs must be performed prior to plan and implement the needed restorative care. If a detailed analysis of occlusion is needed, this should be performed during a comprehensive prosthodontic examination. For most Operative Dentistry procedures, an evaluation and recording of static and dynamic occlusal relationships is adequate. Caries assessment: To understand the clinical situation, and to have proper protocol for clinical decision-making for diagnoses and treatment planning in conjunction with caries risk assessment, the following questions need to be considered: 1) Is there caries present? (caries detection methods are mainly: visual examination, bitewing radiograph, Diagnodent laser fluoresence). 2) How can caries be detected? (caries detection requirements are: proper vision, proper lighting, bitewing radiograph, and transillumination). It has to be stressed that the use of an explorer to detect a catch in pits and fissures is not considered acceptable today as lesions may be iatrogenically induced in areas that could be treated non-surgically. An explorer can be only used as a diagnostic tool only on its side, with no pressure, on smooth surfaces, to determine roughness of enamel. 3) Where is the caries located? (teeth and surfaces). 4) Does the caries involve enamel only or dentin as well? (Carious lesions may appear as non-cavitated white lesions in enamel, or lesions may involve enamel and dentin and cause significant destruction). 5) Is the lesion cavitated? 6) Can the lesion be treated by a non-surgical approach? 7) What is the future risk of caries in the particular patient? (low, medium, or high risk of caries). This is determined through proper assessment of caries. The patient medical and dental history will partially answer this question, for example, taking specific medications that may negatively reflect the oral health and Page 4 of 57 lead to presence of side effects on oral cavity. Furthermore, dietary habits, sugar intake, level of plaque control, usage of fluoride, tooth brushing and mouthwashes. Clinical examination on the other hand will be needed to have a proper overview about the oral health and risk of caries. Therefore, the following systems are used to assist in diagnosis and management of caries: a) International caries detection and assessment system (ICDAS): The ICDAS is a detection and assessment system used to assist dental practitioners in their clinical practice to properly diagnose and manage caries appropriately, using evidence-based and preventively oriented approach. This system provides flexible internationally accepted methods for classifying stages of caries process and activity status of lesions. The proper diagnosis of caries lesion is an essential requirement toward providing the best possible treatment in order to preserve the tooth structure. The ICDAS system classifies the lesions according to their biological and radiographical representation and appearance. It also helps make clinical decisions related to surgical or non-surgical treatment of a lesion. Three main terms from this system are used in diagnosis of caries that include: 1) Carious lesion detection (involves an objective visual method to determine the presence or absence of the disease). 2) Carious lesion assessment (to characterize and monitor the detected carious lesion). 3) Caries lesion diagnosis (that should involve professional summation of all available data). Page 5 of 57  The ICDAS scores are used to assess the presence and extension of caries lesion and decide for the type of intervention. These scores are described in this table: Score Criteria for clinical visual- Scores for bitewing radiographical tactile examination classification of lesion severity 0 Sound tooth structure. No radiographical changes. 1 First visual change in the Radiolucency in the outer half of the enamel. enamel. 2 Distinct visual change in the Radiolucency in the inner half of the enamel. enamel ± Enamel-Dentin junction (EDJ) involvement. 3 Localized enamel breakdown. Radiolucency limited to the outer third of dentin. 4 Underlying dentin shadow. Radiolucency reaching the middle third of dentin. 5 Distinct cavity with visible Radiolucency reaching the inner third of dentin. dentin, with clinical cavitation. 6 Extensive cavity with visible Radiolucency reaches the pulp, with dentin. clinical cavitation. Page 6 of 57 Page 7 of 57 Page 8 of 57 Page 9 of 57 Eventually, both the radiographic (when available and for posterior teeth) and the clinical assessment of the lesion severity end up classifying the lesion into the categories of initial, moderate or extensive. Page 10 of 57 * All diagrams, photographs, tables displayed above are used under written license from ICCMSTM and ICDAS Foundation. https://www.iccms-web.com b) Caries management by risk assessment (CAMBRA): It is a process that presents a management philosophy to control the caries disease process through a medical model. In this process, individualized evaluation of pathological and protective factors, followed by assessment of the risk to develop future disease is performed for the patient. This should result in the preparation of an individualized, evidence-based caries management plan that involves nonsurgical therapeutics and surgical interventions. 3. Pre-operative procedures: If a surgical Operative Dentistry approach is treatment planned, the following steps are performed before starting the operative procedure: 3.1. Administration of local anaesthesia: Appropriate local anaesthesia is indicated in most operative procedures. Its use is important for the patient Page 11 of 57 comfort and for the procedure to be uninterrupted. It can also help in reduction of salivation during the operative procedure. 3.2 Shade selection if the restoration is to be done in the aesthetic zone. Use the Vita Classic shade guide. The reason shade selection is done before any work in the mouth is that the shade of teeth changes with dehydration that happens if the patient remains even a few minutes with their mouth open, even more with rubber dam isolation. In aesthetically demanding cases you may need to do at this time a mock up, by placing the composite material in the shade that you selected and curing it (without bonding) to verify that the actual composite matches properly the tooth structure. 3.3. Isolation of the operating site: proper multiple teeth isolation with rubber dam is indicated with all the restorative procedures. *Guidelines for rubber dam isolation Rubber dam is considered the optimal method to isolate a dental operating field and prevent moisture contamination during the placement of direct, indirect adhesive restorations and endodontic procedures. Other advantages include: improved operator access and visibility, minimization of airborne debris and aerosols and patient safety. Armamentarium: 1. Rubber dam sheets 2. Clamps (or retainers) 3. Punch 4. Clamp forceps 5. Frame 6. Template/stamp 7. Dental floss 8. Lubricant (optional water soluble) 9. Napkin (optional) 10. Wedges 11. Modelling compound (to secure clamps, do not block holes on the clamp) Page 12 of 57 Rubber dam sheet: use medium or heavy dam of good quality (better sealing ability, better retraction of soft tissue, minimal risk of tearing). Use NON – LATEX in cases of latex allergy. Clamps: major anchor clamp is placed on the most posterior tooth. Can be winged or wingless depends on the procedure and the surface to be restored. The clamp should make 4-point contact with the tooth and always check the stability with slight finger pressure on the bow. Consider customization of clamps. Punch: Ideally with 5 different sizes of holes. Make sure that: plunger is well- centered in the cutting hole, so the edges of the instrument remain sharp and produce clean-cut holes because clean cut holes don’t tear easily when stretched during application. The holes of the instrument are clean and tags of rubber from previous cuts do not remain inside the disk. Template: Use as a guide the teeth, a template, a rubber dam stamp or a stone cast. Floss: use floss to tie the clamp, testing contacts before placement, passing the dam interproximally, making ligatures, inverting the dam. *Materials for sealing voids and spaces: Oraseal, light-cured resin barriers, Cavit, Teflon, bite registration material, putty impression material. ALWAYS make sure that there are no spaces from where small materials can escape through them. Priority is SAFETY. *Application techniques: - Clamp first and rubber dam over it - Clamp and rubber dam at the same time - Clamp, rubber dam and frame all together - No clamp technique (anterior teeth) - Split dam (badly broken down teeth, the abutments of a bridge, partially erupted teeth, teeth with deep subgingival margins, anterior teeth and when preparing teeth for full crowns). Page 13 of 57 *How many teeth to include in the isolation field? Single tooth isolation may be used for the following: Fissure sealants, Class I and V restorations, Endodontics. Multiple teeth isolation: Class II restorations, multiple restoration and quadrant dentistry, bonding indirect restorations. *How many teeth to include in the isolation field? Depends on the clinical scenario. - The general rule is to include at least one tooth posterior and two teeth anterior to the teeth being treated. - Anterior teeth from canine to canine minimum. *Removal of the dam Thoroughly clean area, cut /remove floss ligatures and interproximal wedges, remove clamp with clamp forceps, gently stretch and remove the dam (if scissors needed to cut the interdental septas of the dam be careful not to cut any soft tissues), examine dam for any missing pieces, examine site for any remaining rubber pieces and remove them with floss or explorer. *Special cases where rubber dam use is complex: distal surface of last tooth in the arch, subgingival caries, class v cavities, partial erupted teeth. 3.4. Tooth preparation with rotary and hand instruments: Today’s goals in tooth preparation is maximum preservation of tooth structure while optimizing the strength and longevity of the restorative material to be used. The instruments are mainly used to remove the carious lesions, to remove tooth structure needed to obtain proper retention and resistance forms and to assess the tooth preparation. 3.4.1. Hand instruments: Cutting hand instruments include excavators for caries removal and hatchets, chisels, gingival margin trimmers and others to finalize the preparation and remove unsupported enamel in the box of Class II or III preparations, if needed. Page 14 of 57 Non-cutting hand instruments include mirrors, explorers, probes, and other instruments to check the hardness of the remaining dentin, check the final preparation smoothness and depth etc. Most instruments used during the restoration of the tooth preparation are non-cutting hand instruments. 3.4.2. Rotary cutting instruments: These instruments are used with either high-speed or low-speed hand-pieces and are manufactured in different sizes, shapes and types, to be used for particular clinical applications. Latch-type burs are used with low-speed hand- pieces and friction grip burs are used with high-speed hand-pieces. The following rotary cutting instruments are mainly used for Operative Dentistry procedures in the EUC Dental clinic: a) Round burs are used for: initial entry into the tooth, extension of the preparations, preparation of retentive features, caries removal and creating retention coves, points and grooves. Different sizes are used for different tasks. For example, a large round bur that fits loosely in the carious cavity is used for caries removal (size 010, 012 or 014 or US size 2,3 or 4). A small round bur is used to create undercuts (006 or US size ½). b) Pear-shaped burs in small sizes are many times used to punch cut enamel during initial opening of the cavity and for amalgam of composite tooth preparations. c) Cross cut fissure burs and round end cross cut fissure burs are also used for tooth preparation. Both for amalgam and composite restorations, the internal line angles should be rounded to avoid stress concentration. d) Finishing diamonds (fine and ultra-fine) are used to adjust the occlusion and finish the restoration before polishing e) Rubber polishing instruments and aluminium oxide coated disks are used to polish the restorations. 4. The restorative procedure: The aims of restorative management are to: Page 15 of 57 1. Aid plaque control and thereby manage caries activity at this specific location. 2. Protect the pulp-dentine complex and arrest the lesion by sealing it. 3. Restore the function, form, and aesthetics of the tooth. The restorative material to be used must be decided before the tooth preparation starts. When using adhesive materials, conventional removal of carious hard dental tissues and design of the cavity for the material to withstand forces and have adequate retention, cannot be justified. The material of choice today in Operative Dentistry is resin-based composite as this allows for a more conservative preparation, is bonded to tooth structure, is easy to repair and has natural tooth appearance. However, as these are technique sensitive materials, in many cases amalgam may be indicated, mainly in cases difficult to isolate the operative field. EUC Dental clinic complies with the current recommendations for phase down of Dental amalgam and recognises the need for prevention-based treatment and research to obtain a better restorative material than the ones currently available. Glass ionomer cements may also be indicated in limited cases. Evidence shows that more than half of the restorative work done in Operative Dentistry is replacement of old restorations. In EUC Dental clinic we advocate repair instead of replacement of defective restorations, where indicated and students must justify such a decision. Part of the old restorative material can be left in the tooth if : 1) There is no evidence of recurrent caries. 2) The periphery of the base and liner is intact. 3) The tooth is asymptomatic. It is also permissible to repair or replace a defective portion of an existing amalgam restoration if the remaining portion of the original restoration has adequate resistance and retention forms. 4.1. Armamentarium for amalgam restorations: 1) Dental mirror 2) Cotton pliers/Dental tweezers. Page 16 of 57  3) Dental explorer. 4) Air-water syringe tip. 5) Periodontal probe to check the depth of the tooth preparation. 6) Spoon excavators (small and large). 7) Enamel hatchet. 8) Hollenback plugger. 9) Cone burnisher. 10)½ Hollenback carver. 11)Discoid/cleoid carver. 12)Ball burnisher 13)Tofflemire matrix band retainer. 14)Iris straight scissors. 15) Amalgam carrier. 16) Amalgam well. 17) Tofflemire matrix band retainer (for class II) or another appropriate matrix system. 18) Calcium Hydroxide/Glass ionomer cement placement instrument. 19)Glass slab and mixing spatula. 20)Articulating paper forceps. 21)Amalgam capsules. 22)Matrix bands – No 1 universal and No 3 narrow (for class II). 23)Wooden or plastic wedges in several sizes. 24) Dental floss. 25) Burs and diamonds (see section 3.4.2.). 26)Cotton rolls and cotton beads. 27) Finishing and polishing instruments and materials such as brown and green rubber polishers. 28) Rubber dam isolation armamentarium as noted on 3.3. of this guideline. 4.2. Armamentarium for resin based composite restorations: 1) Dental mirror 2) Cotton pliers/Dental tweezers. 3) Dental explorer. Page 17 of 57  4) Periodontal probe to check the depth of the tooth preparation. 5) Air-water syringe tip. 6) Spoon excavators (small and large). 7) Enamel hatchet. 8) ½ Hollenback carver. 9) Plastic instrument/composite placement instrument. 10)Interproximal carver. 11) Sectional matrix system such as Palodent/Dentsply V3 (ring, wedges, bands). 12) Calcium Hydroxide/Glass ionomer cement placement instrument. 13)Iris straight scissors. 14)Articulating paper forceps. 15)Glass slab and mixing spatula. 16)Mylar strips – clear matrix bands. 17)Wooden and plastic wedges. 18) Dental floss. 19) Burs and diamonds (see section 3.4.2.). 20) Finishing and polishing instruments and materials such as rubber points, discs, strips, aluminium oxide paste. 21) Micro brushes. 22) Bonding agent. 23) Vita Classic shade guide. 24) Rubber dam isolation armamentarium as noted on 3.3. of this guideline. 4.2. Tooth Preparation: Tooth preparation is performed to receive either polycrystalline (e.g., dental amalgam, glass-ceramic), or polymeric (e.g., resin-based composite) restorative materials. The design of the preparation takes into consideration the type of dental restorative material. Polycrystalline materials require a specific tooth preparation design and are usually less conservative than the preparations for polymeric materials. The larger the restoration with resin- Page 18 of 57 based composite, the more the need for retention and resistance form, thus the more the preparation resembles the amalgam tooth preparation. 4.2.1. Tooth preparation for amalgam Tooth preparation to receive amalgam restorative material requires accessing the lesion and providing convenience form, removing the diseased/defective tooth structure according to the selective caries removal protocols that (SCR), and providing a resistance and retention form appropriate for amalgam. Specific design requirements for amalgam restorations are: - Preparation depth is between 1.5 to 2 mm. - Cavosurface angle should be as close to 90º as possible. - Isthmus width no more than 1/3rd of the intercuspal distance. - Slightly rounded internal line angles. -The preparation for amalgam usually requires removal of healthy tooth structure, to obtain the primary and secondary retention and resistance forms of restorations (e.g. convergence of facial and lingual walls, smoothness and flatness of pulpal and gingival floors or preparation of retention grooves, slots, coves for secondary retention, if needed). Steps to be taken for Class I tooth preparations for amalgam restorative material: 1) Visualize the finished prep before you even start. 2) Enter in the most carious pit with a punch cut. The long axis of the bur should be parallel to the long axis of the crown. The pear shaped bur No 330 is usually the most appropriate. The bur should rotate all the time when it touches the tooth. 3) Initial depth just inside the DEJ (1.5-2mm) regardless of the lesion depth. Remove all caries from the DEJ (peripherally healthy dentin on the pulpal floor, surrounding any remaining caries). Page 19 of 57  4) Leave a minimum of 1.6mm for premolars and 2mm for molars of intact tooth at the marginal ridges. If undermined by caries, you will need to make a Class II prep. 5) Pulpal floor should be flat but can follow the rise and fall of the occlusal surface. 6) Pulpal floor should always be in dentin, ideally just below DEJ. 7) If the defect is more than ½ the distance between the primary groove and a cusp tip: maybe reduce and cap the cusp. 8) If the defect is more than 2/3 the distance between the primary groove and a cusp tip: Do reduce and cap the cusp. 9) Remove any remaining defective or unsupported enamel and soft dentin on the pulpal floor as indicated (look as SCR protocols). Caries should be removed with spoon excavators and slowly revolving round burs of appropriate size. 10) Pulp protection (bases and liners) as indicated. 11) Prepare secondary resistance/retention form if needed (e.g. grooves or coves). Usually in Class I tooth preps, converging lingual and facial walls provide adequate retention. 12) Finish the external walls. 13)Clean and inspect the preparation. Steps to be taken for two surface Class I tooth preparations for amalgam restorative material (e.g. Occluso – lingual on a permanent first maxillary molar): 1) The occlusal part of the prep is similar to Class I amalgam preparation. 2) The lingual extension should be no larger than necessary. Ideally the mesio-distal width of the prep should be 1mm. 3) Move towards the oblique ridge rather than centering over the fissure to preserve the disto-lingual cusp. 4) Extend as little as possible towards the DL cusp to avoid fracture. 5) Extend as little as possible towards the D marginal ridge (keep the 2mm remaining thickness rule). Page 20 of 57  6) Occlusal portion may have a distal tilt to conserve the dentin support of the distal marginal ridge. 7) Axio-pulpal line angle should be rounded. 8) Keep uniform depth. 9) Prepare grooves on the mesio-axial and disto-axial line angles. Steps to be taken for Class II tooth preparations for amalgam restorative material: 1) The occlusal part of the prep is similar to Class I amalgam preparation. 2) Enter the pit nearest the involved proximal surface with a punch cut with No 330 pear shaped bur. The long axis of the bur should be parallel to the long axis of the tooth. Include the opposite pit if carious. If not carious, we will perform a box only preparation to avoid unnecessary removal of healthy tooth structure. 3) Initial depth just inside the DEJ (1.5-2mm) regardless of the lesion depth. 4) Isthmus width as narrow as possible, preferably no wider than one quarter the inter-cuspal distance. Caries lesion at the DEJ will determine the amount of preparation extension and width. So far the marginal ridge is not broken yet. 5) Dovetail extension in the fissures provides also primary retention form but it is not required if radiating fissures are not present. 6) Maintain the established pulpal depth and with the bur parallel to the long axis of the tooth, extend the prep proximally, stopping approximately 0.8 mm short of cutting through the marginal ridge into the contact area. The occlusal is made slightly wider faciolingually than in the Class I preparation because additional width is necessary for the proximal box. 7) Proximal prep: Move towards ML and MF margin and push slightly the bur at the gingival floor level until you almost break the enamel. The presence of the proximal enamel limits the chances of iatrogenic damage to the adjacent tooth. If the remaining enamel breaks during cutting, use a metal matrix on the adjacent tooth to protect it. Keep in mind that this is a visual aid and not good protection. Page 21 of 57  8) Break away the remaining enamel at the marginal ridge with a spoon excavator. Pre-wedging may separate the teeth and protect the adjacent enamel and gingiva. 9) Include all caries lesion, defects, existing restorative material and unsupported enamel being extremely careful not to cause iatrogenic damage to the adjacent tooth. Iatrogenic damage is a critical error and the clinical exercise will receive an F grade. 10) Create approximately 90-degree cavosurface margins (i.e., butt-joint margins). 11) Establish (ideally) not more than 0.5mm clearance with the adjacent proximal surface facially, lingually, and gingivally. 12) Prepare gingivally along the exposed proximal DEJ. 13) Extended gingivally just beyond the caries lesion or the proximal contact, whichever is greater. 14) The axial wall dentinal depth varies based on the gingival extension of the preparation. 15) The axial wall follows the faciolingual contour of the proximal surface and the DEJ. This means that the axial wall is slightly convex and not concave. This is a mistake easy to happen if you use a larger bur than needed. 16) Establish the proper faciolingual extension. 17) Faciolingual dimension of the box is larger at gingival than occlusal to provide retention form (converging walls). 18) Remove remaining proximal unsupported enamel and smoothen the cavity with enamel hatchet. 19) Remove soft dentin and old restorative material, do pulp protection and prepare secondary retention form as indicated. 20) Retention grooves should be separate on the occlusal and the proximal. In the proximal, prepare them with an appropriate bur at the bisector of the axio-facial and axio-lingual line angles. The smaller the prep, the less the need for retention. Variations: 1) Mandibular first premolar: Page 22 of 57  a. Tilt the bur for entry. The long axis of the bur should be parallel to the bisector of the angle of the long axis of the tooth and the line perpendicular to the faciolingual cusp points. b. If the opposite pit is carious and the transverse ridge is not undermined, do a separate restoration. c. Grooves are always necessary. 2) Maxillary first molar: a. When the oblique ridge is unaffected, do MO + DO instead of MOD preparations. b. If the oblique ridge is affected, extend to the distal pit. 3) Maxillary first premolar: a. The mesial embrasure is in a highly esthetic area.Try to avoid buccal extension of the proximal box for retention form. Steps to be taken for Class V tooth preparations for amalgam restorative material: 1) Properly isolate. Retraction cord may be needed if the lesion extends subgingivally. 2) Extend the cavosurface margin to sound tooth structure. 3) Enter the lesion with an appropriate bur to an initial depth of 0.5mm inside the DEJ (1 – 1.25mm total axial depth). 4) 0.75mm inside cementum when on root surfaces. 5) Keep the bur tilted so it does not move laterally instead of axially. 6) All external walls should be perpendicular to the external tooth surface (parallel to the enamel rods). 7) Change the bur orientation depending on the convexity of the tooth. 8) Because all walls are perpendicular to the tooth surface, they diverge, so two retention grooves must be prepared to achieve retention form. The depth of the grooves should be 0.25 – 0.5mm and they should be placed at the occluso-axial and the gingiva-axial line angle. A number ½ (006) round bur should be used to prepare the grooves. Alternatively, four axial coves can be prepared, one on each axial point angle. Page 23 of 57 Matrix placement for amalgam restorations: As a general rule, the easiest matrix system that covers the needs of the case should be selected. In many cases, a matrix is not needed for occluso-lingual and occluso-buccal Class I, or for Class V restorations. Most Class II restorations require a matrix. The standard (Universal) matrix system for amalgam restorations is the straight Tofflemire retainer with the universal No 1 and narrow No 3 metal bands, in combination with wooden or plastic wedges. A similar alternative is the Ivory system. Placement of the Tofflemire/Ivory matrix system for class II preparations: 1) The retainer is always placed buccally. 2) The procedure is started by folding the band to make a funnel like loop with the narrow opening facing the gingiva and the wide opening facing the occlusal surface. 3) The slots on the head and the slide should face you when you place the band and always face the gingiva when you place the retainer on the tooth. 4) The band is facing to the left (slots facing up, head facing front) for quadrants 2 and 4 and facing to the right (slots facing up, head facing front) for quadrants 1 and 3. 5) Both ends of the band are inserted inside the diagonal slot of the tofflemire head, 1-2mm beyond that, and tightened by the set screw. For a smaller tooth (e.g. premolar), you can have the band extending 3-4mm beyond the diagonal slot. 6) Before you place the band in the retainer, burnish it with an ovoid burnisher to give the proximal area similar contour with the adjacent tooth. 7) The matrix band should be slightly higher (around 1 mm) above the adjacent marginal ridge, to allow proper building of the marginal ridge with amalgam. Page 24 of 57  8) The rotating spindle is used to adjust the band loop opening size and should be rotated until the matrix is tight around the tooth. 9) Make sure the band is extending gingivally at least 1-2mm past the gingival floor. 10) Insert a wooden or plastic wedge (or wedges) properly in the proximal surface to ensure a tight adaptation of the band to the tooth at the level of the gingival floor, to avoid amalgam overhangs. The wedge is usually triangular and the base of it should face apically. 11) After the restoration is completed, the band is removed by unscrewing the set screw, removing the Tofflemire retainer first and then remove the band in facial-occlusal and lingual-occlusal direction, with caution to not fracture the unset amalgam marginal ridge. 4.2.2. Tooth preparation for resin-based composite Preparation of tooth structure to receive resin-based composite restorative materials only requires access to the lesion and creating convenience form, removal of the diseased/defective tooth structure and old restorative material as indicated, followed by restoration of the natural tooth anatomy. Usually, no mechanical retention features are prepared and adequate retention is provided by bonding. No minimum material thickness or any particular design is required for this type of restorative material. Therefore, resin-based composite is a material that allows minimal preparation and maximum conservation of the natural tooth structure. - Appropriate enamel bevelling is required where indicated, for three reasons: a) increase surface area (retention form), b) more favourable orientation of the enamel rods, resulting in better etching/bonding results and c) for aesthetic blending of composite through. - Large tooth preparations may require additional removal of healthy tooth structure, to obtain retention and resistance forms. Small to moderate Class I composite restorations: 1) Use minimally invasive approaches. Page 25 of 57  2) No typical resistance of retention forms needed. 3) No uniform pulpal or axial walls are needed. 4) Depth is only determined by the selective removal of carious tooth structure. 5) Use a small round or pear shaped bur and be as conservative as possible. 6) If the smallest composite placement instruments does not fit in the tooth preparation, use flowable composite, in combination with restorative composite. 7) Less involved or at-risk intact areas can be sealed. Moderate to large Class I composite restorations: The larger the tooth preparation, the more it resembles the amalgam tooth preparation. 1) Flat walls perpendicular to the occlusal forces should be prepared. 2) All unsupported enamel should be removed. 3) The preparation should never be excessively extended beyond removal of faulty structures to justify resistance and retention forms, as this will further weaken the tooth structure and can ultimately lead to failure of the tooth-restoration unit. 4) Use an elongated pear-shaped bur as it will result in strong, 90o cavosurface margins. You can also use a round bur. 5) All internal line angles should be rounded. 6) Enter in the most carious pit with the bur parallel to the long axis of the tooth. 7) Enter at an initial depth just inside the DEJ. Remove all caries at DEJ until you reach hard dentin. Follow the steps for SCR, pulp protection etc. 8) At least 1.5mm for premolars and 2mm for molars should remain at the marginal ridges. 9) The outline form should be as conservative as possible. Page 26 of 57 Class II composite restorations: 1) Remember that one of the most difficult tasks in Class II composite restorations is to achieve a tight proximal contact. Pre-wedging may be helpful. Placing the sectional matrix ring serves the same purpose. 2) Visualize faciolingual proximal box extensions. 3) Use a small round or elongated pear shaped bur or diamond. 4) Remove all unsupported enamel with an enamel hatchet or a small rotary cutting instrument. 5) When there is no occlusal caries, do a box only preparation. 6) Axial depth is determined only by the extent of the lesion. 7) Facial, lingual and gingival extensions are determined by the extent of the lesion. No clearance is necessary with the adjacent tooth at the gingival floor level (the margin can be left in the contact area). 8) We still need a 90o facial and lingual margin, indicating there is no unsupported enamel. 9) Gingival enamel is very important for bonding so keep it if possible. 10)Selective caries removal protocols are followed, as always. 11)No secondary retention form and no bevels are required. Class III composite restorations: 1) Access is always lingual for a better aesthetic result, unless: a. The lesion is extending to the facial. b. The teeth are not straight and direct access to the proximal is possible. c. Too much removal of sound tooth structure is needed. d. Old restoration extends to the facial surface. 2) Enter with a small round bur as close to the lesion or defect and as close to the adjacent tooth, without contacting it. 3) Use the same bur to enlarge the opening for caries removal and convenience form, while establishing the initial axial wall depth. 4) Extend the outline form just enough to include the peripheral extent of the lesion. Page 27 of 57  5) Axial wall 0.2mm in dentin, following the contour of the tooth. 6) Do not prepare distinct or uniform axial preparation walls. The objective is to selectively remove carious tissue as conservatively as possible. 7) Bevel at 45o the accessible enamel margins. Use a flame shaped diamond.The width of the bevel should be 0.5-2mm depending on the size of the prep, the location of the margin and the aesthetic needs of the case. 8) If the restorations extends on the facial surface, the bevel should be longer, at 30o for better aesthetics. 9) Do not bevel if: a. You are going to completely remove enamel. b. If you will have composite at the centric occlusal contact. Class IV composite restorations: In addition to the steps taken for Class III: 1) Bevel all surfaces. 2) Long bevel on the facial. 3) Place retention grooves with a small round bur. Class V composite restorations: 1) Bevel typically only the occlusal/incisal margin and feather towards the proximals. 2) Sclerotic dentin and larger Class Vs may require additional retention. Matrix placement for composite restorations: As a general rule, the easiest matrix system that covers the needs of the case should be selected. A matrix is not needed for occluso-lingual and occluso- buccal Class I, or for Class V restorations. The matrix system of choice for Class II composire restorations is the sectional matrix system (e.g. V3 or Garrisson). Page 28 of 57 This system aids in achieving a tight proximal contact. In case of MOD tooth preparations, either two sectional matrices are placed, or a Tofflemire universal retainer with aggressive wedging is used. Placement of the sectional matrix system for class II composite preparations: 1) Placement of the sectional matrix band in the proximal preparation without pressure. Placing of the sectional matrix ring before the preparation will help loosen the contact during preparation and the band will go easier in the proximal area. Similarly, pre-prep aggressive wedging will help. 2) Insertion of the plastic wedge to obtain proper adaptation of the matrix band with the closely gingival contour of the proximal box. 3) Placement of the metal ring as a saddle on the wedge to secure the band. 5. Management of dental caries and pulp protection: The principles for the removal of carious tooth structure in vital, asymptomatic teeth (with no signs of irreversible pulpitis) are: 1) Preserve non-demineralized and remineralizable tissue. 2) Achieve an adequate seal by placing the peripheral restoration onto sound dentine and/or enamel, thus controlling the lesion and inactivating remaining bacteria. 3) Maintain pulpal health by preserving residual dentine (avoiding unnecessary pulpal irritation/insult) and preventing pulp exposure (i.e., leave soft dentine in proximity to the pulp if required). 4) Maximize longevity of the restoration by removing enough soft dentine to place a durable restoration of sufficient bulk and resilience. In deep lesions (radiographically involving the inner pulpal third or quarter of dentine or with clinically assessed risk of pulpal exposure), preservation of pulpal health should be prioritized. In shallow or moderately deep lesions (those not reaching the inner third or quarter of the dentine), restoration longevity might be more important and you need to remove all soft dentin. Page 29 of 57  Non-selective removal to hard dentin (complete caries removal) is considered over-treatment and is no longer advocated. In EUC Dental clinic we do not advocate the use of temporary restorative materials to evaluate the condition of the pulp or the stepwise caries excavation technique (2-step excavation after 6 months to a year) as we believe that re-visiting the cavity may increase the risk of pulp exposure and need for endodontic therapy. We do advocate a protocol for proper follow up evaluation of the condition of the pulp and necessity for endodontic treatment. 5.1. Selective caries removal (SCR) protocol: 1) Always remove all caries to normal (hard) dentin at DEJ (scratchy feeling after removal). 2) Selective caries removal to firm dentin (formerly called affected dentin) in small and moderate carious lesions, not reaching the inner (pulpal) 1/3rd of dentin (feeling of some resistance with a hand excavator). In deeper lesions, selective removal to firm dentine bears significant risks for the pulp, which is why other strategies should be considered. 3) Selective caries removal to soft dentin (formerly called infected dentin) in moderate to large carious lesions, reaching the inner (pulpal) 1/3rd of dentin. In other words, soft caries is left over the pulp to avoid pulp exposure and stress, thereby promoting pulpal health. Selective removal to soft dentin significantly reduces the risk of pulp exposure as compared with other approaches. 5.2. Placement of pulp protection/bases and liners materials: The general requirement is to have 2mm of tooth structure or liner/base materials between the pulp and the restorative material (either amalgam or composite). Several protective biomaterials are used for indirect or direct pulp capping (e.g. MTA, Ca(OH)2, or Biodentine). These materials are placed in order to create a protective physical and thermal barrier to the pulp, and to allow Page 30 of 57 healing and repair. Furthermore, they reduce the configuration factor (C factor) to reduce the shrinkage stress developed with composite resin materials. This means that if we have 2mm of dentin, we will be placing no pulp protection materials and will proceed directly to bonding procedures for composite restorations or desensitizer placement for amalgam restorations. 5.2.1. Indirect pulp capping 1) As mentioned before, every effort should be made to avoid pulp exposure, by exercising SCR protocols. 2) If there is 1-2mm of dentin remaining, place a thin layer of resin modified glass ionomer cement (RMGIC) or glass ionomer cement (GIC). 3) If there is less than 1mm of dentin thickness remaining or pink color from the pulp showing through dentin (0.5mm of dentin remaining), place a mineral trioxide aggregate-based material (MTA), or calcium hydroxide (Ca(OH)2)-based material. Cover with RMGIC or GIC and proceed with normal restorative procedures. 5.2.2. Direct pulp capping 1) If pulp exposure happens and bleeding starts from the pulp, wash the cavity with sterile saline and try to control haemorrhage by applying pressure with a cotton pellet for a few seconds. If the bleeding stops, proceed with direct pulp capping procedures. If it does not stop, root canal therapy should be initiated. 2) Place MTA (gold standard for pulp capping), or Ca(OH)2 based material in the exposure site and cover with RMGIC or GIC until you reach 2mm from the pulp. 3) Proceed with normal restorative procedures. 4) An 1 year follow up is recommended with vitality testing (at 1 week, 1 month, 3 months, 6 months and 1 year) and periapical radiograph at 6 months. Mixing and placement of Ca(OH)2 and MTA: Page 31 of 57  1) Small but equal amounts of the calcium hydroxide base and catalyst are placed on paper or glass mixing pad. 2) Mixing spatula is used to mix the two materials together thoroughly and properly for 5-10 s, until a homogenous, uniform mixture is formed. Mixing can be also done with the Ca(OH)2 placement instrument. 3) The Ca(OH)2 placement instrument (or a small ball-pointed instrument) is used to carry and place the mixed material on the exposure site. The Ca(OH)2 usually takes 1-2 minutes to set so try work fast. 4) For MTA, follow the ratio of powder and liquid recommended by the manufacturer and follow the same placement protocol. *Important note: Avoid placement of the mixed materials on the walls or margins. Also, avoid placing large amount. If you accidentally placed them on the walls and they set before removing them, you will have to re-visit the cavity with a bur. Mixing and placement of RMGIC or GIC: 1) Dentin should be slightly moist prior to placement of RMGIC or GIC. 2) One drop of liquid and one spoon of powder are dispensed on a glass or paper mixing pad. Be careful, these materials are sensitive to powder/liquid ratio. 3) The two components are properly mixed by folding the powder into the liquid for 15 s, using mixing spatula, until a homogenous cement is formed. 4) A calcium hydroxide applicator is used to pick the cement and place it in the preparation. 5) Light-cure if the cement is light-curable for 40 s. After the full setting of GIC occur, the surface appearance of it changed from shiny to dull. 6) If some material was accidently placed on the walls, they need to be removed with a bur. Page 32 of 57 6. Restorative procedure 6.1. Amalgam restorations Before starting the amalgam restorative procedure, ensure preparation of all the armamentarium and materials needed to complete the restorative procedure. 1) Rubber dam isolation (multiple teeth isolation). 2) Ensuring the visibility of all the anatomical structure of the prepared cavity (walls, box, pulpal floor, gingival floor). 3) Placement of matrix system for class II. Carefully inspect the box/matrix at the gingival floor level to be sure that amalgam will not escape and cause overhang over the margins. 4) Place desensitizer. 5) Mixing the contents of amalgam capsule in the amalgamator, according to the settings specified by the manufacturer. 6) Place the mixed amalgam in the amalgam well. 7) Amalgam carrier is used to carry and transfer the amalgam to the preparation. 8) Amalgam should be placed in increments. The first increment should be placed in the box. 9) Proper size amalgam condenser is used to condense the amalgam and push it towards the floor and the walls of the preparation. 10) Add more increments of amalgam, until overfilling the preparation by approximately 1 mm. 11) Strong condensation is important to prevent formation of voids and gaps between amalgam increments, and to ensure complete coverage of the margins of prepared cavity. 12) Amalgam burnisher is used to pre-carve burnish the overfilled amalgam. 13)Amalgam carving starts immediately after burnishing. Several sharp instruments are used to carve the amalgam, in order to restore the anatomical characteristics (grooves, fissures, ridges). Page 33 of 57 14) The tip of the explorer is used to carve the amalgam at the marginal ridge, which should be at the same level with the adjacent tooth, as well as the contact area with the adjacent tooth. 15) After careful removal of the matrix band, work more on the occlusal anatomy using carvers. 16) The tip of a carver or explorer or ½ Hollenback is used to remove any excess amalgam, especially in the occlusal grooves of the tooth. 17) Post-carve burnishing smoothens the amalgam margins. 18)Examine carefully the anatomy. 19) The interproximal contacts should be checked with dental floss. 20) The occlusion should be carefully, and properly examined and adjusted. To check the occlusion, patient is asked to occlude his or her teeth together lightly and move the mandible in all directions. Shiny areas of amalgam should be removed before it is fully set, using a carver. The articulating paper is used later to ensure absence of high points. Care needs to be exercised as if the amalgam started to set, fractures may happen during checking the occlusion. Try to work precisely but fast. 21) Rub the accessible amalgam surface with a wet cotton pellet. 22)Evaluation of the restoration, especially at the interproximal and contact area, should be double-checked, to avoid presence of debris, excess, overhangs. 23) Postoperative instructions should be given to the patient, which include: a) Patient should not eat or chew anything for at least two hours. b) Patient should not eat or chew on the side of the new restoration for at least 12 hours. c) If anaesthesia is given, patient should avoid biting on the lips or tongue. d) Patient may experience postoperative sensitivity to hot or cold for a few days. 24) Finishing and polishing of restoration could be performed after 24 hrs. 6.2. Resin based composite restorations Page 34 of 57 Restorations with resin-based composite materials rely on bonding with appropriate dentin bonding agents (DBA). The proper used of DBAs will determine in large the performance and longevity of the restoration and is considered of paramount importance. 6.2.1. Bonding agent selection and application: There are many classifications of Dentin Bonding Agents (DBAs) and in EUC Dental clinic we are following the strategy-based classification. In this, DBAs are classified as: 1) Etch and Rinse (ER - formerly called total etch). a. Three step. b. Two step. 2) Self-etch (SE). a. Two step. b. One step (Universal). 3) Self-etch with Selective Enamel Etching (SEE). a. Two step + SEE b. One Step (Universal) + Properties of DBAs The ideal properties of a DBA are: 1) Low technique sensitivity, as possible. 2) Strong enamel acid etching with phosphoric acid (H3PO4). 3) Mild dentin self-etching, for self-etch bonding agents. 4) To have a final hydrophobic layer to avoid fast degradation of the bond through nanoleakage. 5) To be not acidic after light-curing to avoid hydrophilicity and fast degradation of the bond through nanoleake and water tree formation. 6) To be dual cure to safely be used during indirect bonding procedures. Page 35 of 57  7) To have dual cure compatibility to avoid incompatibility with self-cure and dual-cure resins, and mainly resin cements. 8) To contain the powerful monomer 10-MDP. Not all properties can be found in any given material and it is certain that there is a lot of room for improvement for these materials. However, it is widely shown in the literature that convenience drives the market and that simplified DBAs offer a significantly reduced performance, either for ER or for SE bonding agents. So, the bonding agents that appear to be the best choice today are: 1) The 2 step, mild pH self-etch systems, necessarily with the additional selective enamel etching step with H3PO4. 2) The 3 step etch and rinse systems (formerly called 4th generation). The two step ER systems (H3PO4 and one bottle – formerly called 5th generation) and the one step self-etch Universal systems that are widely used in Dental practices today can be used only in cases where lower performance and longevity of the bond is acceptable, and only for convenience reasons, and their use is not advocated by EUC Dental clinic. During placement of the adhesive, it is very important to follow the manufacturer’s recommendations. Pay careful attention to immediately close the bottle and immediately place the DBA on the tooth, as the solvent is evaporating fast. Application of a two-step self-etch system (e.g. Clearfil SE Bond 2, Kuraray) with selective enamel etching: 1) Acid-etch enamel for 30 seconds. Pay careful attention to only etch enamel and not dentin. 2) Rinse thoroughly with water (using air-water syringe) for 5-10 seconds. 3) Remove excess water without totally drying the dentin, to avoid desiccation and collagen collapse. Depending on the solvent, different amount of moisture is needed. More for acetone solvents, medium for ethanol solvents and almost dry for water containing solvents. 4) Application of the primer (Primer bottle): Page 36 of 57  - dispense the necessary amount of Primer into the well or directly on the micro-brush. - apply primer to the entire cavity using the microbrush (two layers). Rub the primer on dentin for a few seconds. - Apply air with the air-water syringe gently and mildly from further away, for 5 s, to evaporate solvent (do not desiccate). 8) Application of the bond (Bond bottle): - dispense the necessary amount of Bond into the well or directly on the microbrush. - apply the bond to the entire cavity, with the microbrush. - Apply air with the air-water syringe gently and mildly from further away for a couple of seconds to spread the bond. - Light-cure for 20 s. 9) Continue with the restorative procedure. Application of a three step-etch-and-rinse system (e.g. All-Bond 2, Bisco): 1)Acid-etching of enamel and dentin, using 32-38% H3PO4 for 30 s. 5) Rinse thoroughly with water (using air-water syringe). 6) Remove the excess of water, leaving the dentin moist, to avoid collagen collapse. 7) Application of Primers A and B: - Dispense one drop of primer A and one drop of primer B and mix them. - Apply 5 consecutive coats to the enamel and dentin. - Do not dry between coats. - Apply air gently and mildly for 5 sec to evaporate the solvent. 8) D/E resin is applied on enamel and dentin. 9) Light-cure for 20 s. 10) Proceed with the restorative procedure. Page 37 of 57  *Important note: In case of contamination with saliva or blood, YOU HAVE TO repeat the procedure! Stop the procedure, proper rubber dam isolation, and restart with etching. 6.2.2. Composite application: Before starting the restorative procedure, ensure preparation of all the armamentarium and materials needed to complete the restoration. The following steps are performed to restore the preparation with resin composite: 1) Rubber dam isolation (multiple teeth isolation): no restorative procedure is allowed without proper isolation. 2) Ensuring the visibility of all the anatomical structure of the prepared cavity (pulpal floor, gingival floor of the box in class II preparations, marginal walls, and the bevelled cavosurface margins). 3) Placement of sectional matrix system for class II preparations: 4) Incremental build-up of the composite (each increment should up to 2 mm thick). Plastic instrument and other hand instruments can be used to apply and adapt the composite to the walls and floor of the prepared cavity. Increments should be placed diagonally (without connecting opposing walls) to reduce the polymerization shrinkage stress. a. For class II restorations (posterior teeth), start with building up the mesial or distal box, then move to the occlusal surface. b. For class III and IV restorations (anterior teeth), a clear matrix band (Mylar strip) should be used. 5) Sculpt carefully the contour and anatomy of the restoration. Remember that the easiest way to achieve proper anatomy is through proper sculpting before curing, not by finishing procedures. 6) Light-cure each increment of composite for 40 sec with a clean and inspected with a radiometer curing device. 7) Adjust the occlusion. 8) Finish and polish the restoration with appropriate means according to the location of the restoration. Page 38 of 57 7. Minimally invasive procedures in operative dentistry clinics: The aims of the minimally invasive dentistry is to improve the remineralization and decrease the demineralization process. It involves conservative composite restorations, pit and fissure sealants, and resin infiltration (ICON). It also involves preventive measures such as application of low and high fluoride concentrations to improve the remineralization and decrease the demineralization. Other preventive measures include: dietary advices, regular control of biofilm by brushing and flossing, xylitol gum use etc. 7.1. Pit and fissure sealants: Deep pits and fissures in enamel are prone to caries and can be sealed with fluid resin (low-viscosity), after acid-etching, to prevent caries formation. Sealants are used as a preventive or therapeutic measure, depending on the individual caries risk, tooth morphology, and presence of incipient enamel caries. Pit and fissure sealants are most effective when applied on newly erupted permanent posterior teeth in children. Furthermore, sealants can be applied on the posterior teeth in adults susceptible to caries, due to diet changes, or presence of medical conditions leading to reduction in salivary flow. When a sealant is treatment planned, the only other option is to do nothing. Clinical procedure for sealant placement: No anaesthesia is needed for this procedure. The clinical steps are: 1) Proper isolation with rubber dam. 2) Cleaning of the occlusal surface (with pumice and water). 3) Proper washing and drying with air-water syringe for 30 s. 4) Acid-etch the occlusal surface with 32-38% H3PO4 for at least 30 sec. 5) Wash thoroughly with water for 10 s, using the air-water syringe. 6) Dry completely (desiccate). Properly etched enamel should appear frosty white and rough. 7) Placement of DBA is optional. 8) Placement of sealant in the deep pits and fissures only. A Microbrush or an explorer is used to tease and distribute the sealant material in the deep pits and fissures and to remove the excess material. Page 39 of 57  9) Light-cure for 40 s. 10) Check the occlusion with articulating paper, to detect and remove high points. Usually adjustment of occlusion is not needed. 7.2. Conservative composite restorations/Preventive Resin Restorations (PRR): A preventive resin restoration is indicated when a small but cavitated carious lesion is present in the pits and fissures of a previously unrestored tooth and the adjacent pits and/or grooves are clinically free of caries. An ultraconservative prep is made and restored with flowable composite. This procedure is performed to also seal the radiating non-carious pits and/or fissures that are at high risk of initiating caries. Tooth preparation for conservative composite restorations can be completed with alternative means such as air abrasion, lasers, and ultrasonics. Clinical procedure for PRR: No anaesthesia is needed for this procedure. The clinical steps are: 1) Proper isolation with rubber dam. 2) Cleaning of the occlusal surface (with pumice and water). 3) Prepare the pits and fissures as indicated, using rotary cutting instruments (burs or diamonds), air abrasion, lasers or ultrasonics. 4) Acid-etch the occlusal surface with 32-38% H3PO4 for 30 sec. 5) Wash thoroughly with water for 10 s, using the air-water syringe. 6) Removing the excess water and leave moist as required by the DBA to be used. 7) Place the bonding agent as explained in 7.2.1. 8) Light cure the DBA for 20 s. 9) Place flowable composite, tease it and spread it on the pit and fissure area. 10) Light-cure the composite for 40 s. Page 40 of 57  11) Apply sealant or the same flowable composite on the other pits and fissures of the same tooth. 12) Light-cure the sealant for 40 s. 13) Check the occlusion with articulating paper, to detect and remove high points. Usually, minimal adjustment of the occlusion is not needed. 8. Other restorative procedures performed in operative dentistry clinics: 8.1. Direct post and core (metal and fiber): The primary purpose of a post is to retain a core in a tooth with extensive loss of coronal tooth structure. They should only be used when other options are not available to retain a core. The amount of remaining coronal tooth structure and the functional requirements of the tooth determine whether a tooth requires a post. Presence or absence of ferrule is one of the most significant factors for the prognosis of the restoration/tooth irrespective of post system and cementation protocol. Principles for posts Apical seal: at least 4-5 mm of radiographic gutta-percha should be retained Length: 2/3 of the root length or at least equal of the clinical crown (and many other similar rules). Summarizing all the rules, the post should be as long as possible and extend to the gutta-percha without voids, bearing in mind limitations such as root length, root morphology (root curvature, root concavities) and without compromising the apical seal of gutta-percha Diameter: Post diameter should not exceed 1/3 of the root diameter at any location. Ideally, the post should fit the canal shape produced by the endodontic procedure without further removal of dentine Shape: usually parallel sided but also root shaped to prevent removal of dentine at middle and apical third of the root. Page 41 of 57 Material: metal (titanium alloys or stainless steel) or fiber posts. Active Vs Passive: Active threaded posts are not recommended as they can lead to root fracture. Posts should sit in the prepared canal space passively without engaging with the dentine directly for retention. Post space preparation *Important note: Check X-ray after completion of RCT to assess root length and width. Also, check notes for working length and reference points. Removal of gutta-percha:  Ideally with heated or mechanical instruments (gates-Glidden drills or piezo reamers). Canal and post preparation:  Always perform under rubber dam isolation  Create clean canal walls for bonding  Post drills are typically included with prefabricated post kits  A post should be selected to fit the space created during endodontic treatment without significant alteration of the canal (ideally a post should range between 0.6-1.2 mm depending on the tooth)  AVOID iatrogenic damage!  Take an X-Ray to confirm clean post space and working length  Post should reach PASSIVELY the desired length  Trim the post according to the clearance required. Fiber-post surface treatment  Different techniques are proposed with no consensus and not clear clinical significance  Most of the fiber post systems provide combination of micro and macro mechanical retention therefore no need to etch, prime or silanize the post. Page 42 of 57 Cementation of fiber post:  Conventional resin cement is recommended for all types of posts (conventional are the ones that require a bonding agent)  Use 3 steps etch and rinse or 2 steps self-etch systems always in Dual Cure mode (an activator should be added at the final hydrophobic step) or according to the manufacturer’s instructions.  Apply on the post the final hydrophobic resin contained in the last bottle of the bonding agent mixed with the activator as a wetting agent.  Use micro brushes and remove excess bonding agent (blotting the micro brushes, paper points or thin special suctioning systems). Μmake sure that the micro brush is of size to reach the working length.  Apply on the post the dual cure or self-cure resin cement before insertion in the canal. Apply resin cement in the canal with appropriate delivery systems  Always make sure of the compatibility of adhesive systems with dual cure core/cementation materials. Core build-up  A dual cure/self-cure core build up material can be used. In some cases and for some materials, the same core build up material can be used instead of a resin cement for post cementation and also as a core material  Any composite light-cured material can be also used for core build up  If indirect restoration is not planned, similar rules for direct restorations apply (contour, contacts, etc.). Justification should be given if not an indirect restoration is provided.  Posts (metal and fiber) should be completely covered by the restorative material and not be exposed to oral fluids (cut the post 2 mm short from the occlusal surface with high speed under water) Time of space preparation:  If rotary instruments are used for GP removal, post space preparation should be delayed at least 24 Hr after completion of RCT Page 43 of 57  If heated instruments are, used post space can be prepared immediately after completion of RCT. Custom Cast dowel cores (indirect posts):  Directions for post space preparation, impression and fabrication are provided in the fixed prosthodontics guidelines.  Conventional cements (glass ionomer and zinc phosphate) and resin cements can be used. In case of very conical and/or short dowels use necessarily resin cements. Resin cements are the cement of choice for all posts, as you will place a post in a tooth that anyway has this as the last restorative option.  Microetch all metal posts Direct or indirect) with 50μm Aluminium oxide, and clean with steamed air or ultrasonic bath with alcohol and apply ALLOY PRIMER on the bonded surface.  Use the self-cure or dual cure resin cements and bonding agents similar to what was described for the fiber posts or according to the directions of the manufacturer.  Wait until cement is fully polymerized ARMAMENTARIUM 1) Restorative setup and routine disposables 2) Boley gauge or ruler 3) Post sizing drill 4) Dual cure Adhesive system 5) Dual-cure or self-cure resin cement 6) 5-ml syringe 7) Fiber post/Metal post 8) Resin composite restorative material 9) Gates-Glidden burs (no. 2 to 5) 10) Silicone stops 11) Alcohol wipe 12) Microbrushes. 13) Paper points. Clinical technique steps Page 44 of 57 1. Administer local anaesthesia if needed. 2. Estimate the length/diameter of the post using the final endodontic radiograph. 3. Isolate the tooth with a rubber dam. 4. Remove existing provisional and any remaining restoration. 5. Set the Gates-Glidden bur to the desired length with a silicone stop and remove the gutta-percha. 6. Set the post sizing drill (corresponding to the post selected) to the established length with a silicone stop and remove any minor obstructions to seating. Be very careful to not create a perforation. The drill should go easily down in the canal. If it does not, stop immediately and take an x- ray with the drill in the canal. 7. Take a radiograph to confirm adequate gutta-percha removal and that space for post is clean. 8. Check that post fits passively to the desired length 9. Trim occlusal portion of the post to the desired level. 10. Clean the post with an alcohol wipe. If the post is metal micro-etch the surface and then clean it. 11. Apply three step etch and rinse or two step self-etch adhesive. Coat all radicular and coronal tooth structure to be bonded. 10. If etchant is used: Use a 5-ml-syringe loaded with water. Irrigate the canal and surrounding tooth structure with water. Dry with an air syringe; blot the canal with a micro brush. Leave the dentin slightly moist. 13. Apply primer to all dentin surfaces with a microbrush. 14. Evaporate solvent from the coronal dentin with a gentle stream of air. Remove excess primer from the canal by repeated blotting with microbrush. 15. Apply dual-curing adhesive to all dentin surfaces with a microbrush; remove excess from the coronal surfaces. Remove excess adhesive from the canal by repeated blotting with a microbrush. Do not light cure. 16. Attach a new mixing/injection tip to the cement/core syringe; bleed small amount of cement through the tip. 17. Insert the tip to the depth of the canal and inject while withdrawing. Do not overfill. Immediately insert the post and hold it in place with moderate Page 45 of 57  pressure. The post should be inserted slowly to allow dissipation of hydrostatic forces. Remove any excess cement. 18. Wait for self-curing or light-cure. 19. Proceed with core build-up with restorative composite resin or dual cure core build up composite material Alternatives of posts Nayarr core (+/- cuspal coverage) is an excellent alternative for posterior teeth Endocrown is another alternative especially for short teeth and preservation of tooth structure at the most critical peri-cervical area. Example of post and core build-up in one-step https://nam.coltene.com/pim/DOC/BRO/docbro31575a-03-19-en-parapost- x-system-brochuresenaindv1.pdf https://global.coltene.com/pim/DOC/SBS/docsbs30001062-08-14-step-i- paracoresenaindv1.pdf 8.2. Repair of restorations EUC Dental clinic complies with modern operative dentistry guidelines and advocates the repair of restorations, where indicated, instead of replacement. This is another way of reducing the invasiveness of our approach as it is widely Page 46 of 57 shown that every replacement of a restoration leads to a larger restoration and increases the possibility of endodontic complications, fractures and others. Repairs are indicated when the restoration is acceptable and there is no evidence of recurrent caries in all areas except for the one to be repaired, there is adequate retention and resistance form in both the repaired and the new part of the restoration and the tooth is asymptomatic. Repairs are also indicated in indirect restorations that are usually needed because of fracture. Repairs of all materials (e.g. composite, amalgam, porcelain fused to metal crowns, all ceramic crowns, porcelain veneers etc.) are always done with bonded resin based composite restorative material in either flowable or universal viscosity. 8.2.1. Repair of direct restorations 1) Remove the defective part of the restoration or modify the preparation as needed for fractured restorations. 2) The preparation and subsequently the repair material should include enamel so retention via bonding is achieved. Enamel should be bevelled as indicated. In other words, do not repair within the material alone without reaching the tooth surface. Exception is a repair of a restoration due to endodontic access cavity or other cases where adequate retention is provided. 3) Micro-etch with the Microetcher available in the clinic with 50μm aluminium oxide powder all remaining restorative material (amalgam or composite). Rinse with water thoroughly so all Al2O3 particles are removed. 4) Place the bonding agent as explained in 7.2.1. of this manual and light cure for 20 sec. 5) Place flowable or universal restorative composite depending on the size of the repair. 6) Light-cure the composite for 40 sec. 7) Check the occlusion (with articulating paper), and adjust as necessary. 8) Finishing and polish with appropriate means. Page 47 of 57 8.2.2. Repair of indirect restorations Repair or indirect restorations relates to the substrate to be repaired. Examples are provided below and in any case scenario you need to follow the instructions for bonding to a specific indirect restorative material. Porcelain fused to metal (PFM) with exposed metal (aesthetic zone) 1) Shade selection and mock up if needed. 2) Proper rubber dam isolation. 3) Smoothen any rough or sharp porcelain edges with finishing diamonds. 4) Bevel porcelain. Be careful to not undermine porcelain as it will break. 5) Micro-etch with 50μm Al2O3 both metal and porcelain. Clean thoroughly. 6) Apply hydrofluoric acid to porcelain as indicated. 7) Apply silane primer to porcelain. 8) Apply metal primer to the metal. 9) Apply the bonding agent as indicated. Do not use the primer if there is no tooth structure involved. 10) Light cure. 11) Apply resinous opaquer of selected shade (pink opaquer many times gives a great aesthetic result in PFM repairs) and light cure. 12) Place composite resin as indicated. 13) Light cure for 40 sec each increment or layer (if a stratification technique is followed). 14) Check occlusion and carefully adjust. 15)Finish and polish. If there is no metal exposed, repair as for silica based ceramics. Silica based ceramics (e.g. feldspathic, lithium disilicate) 1) Smoothen any rough or sharp porcelain edges with finishing diamonds. 2) Bevel porcelain. 3) Micro-etch with 50μm Al2O3. Clean thoroughly. 4) Apply hydrofluoric acid. Time to apply is material dependent. E.max requires 20sec, feldspathic porcelain significantly more. 5) Apply silane primer. Page 48 of 57  6) Continue with placement of DBA, composite, adjust occlusion, finish and polish. Zirconium oxide Usually, zirconium oxide with overlayed porcelain will break. What breaks is almost always the overlaying porcelain and not the zirconia. If this is the case, repair as you would with PFM with exposed metal and alter treatment for metal with treatment for zirconia. Below, the steps for repairing monolithic zirconia or the exposed zirconia are described. 1) Smoothen any rough or sharp zirconia edges with finishing diamonds. 2) Bevel. 3) Micro-etch with 50μm Al2O3. Clean thoroughly. 4) Apply Zir Clean to clean zirconia. 5) Apply Zirconia primer. 6) Continue with placement of DBA, composite, adjust occlusion, finish and polish. 8.3. Management of non-carious cervical lesions (erosion, abrasion, abfraction) Abrasions, abfractions and erosions are non-carious cervical lesions that do not always require treatment. In every case, of outmost importance is to identify and understand the etiologic factors (e.g. hard tooth-brushing, drinks, food, medications, lifestyle, occupation, para-functional habits) and apply preventive measures to avoid further loss of tooth structure. The causes, complexity, and severity of the condition is determining the management options. If the problem is minimal and the tooth is asymptomatic, monitoring may only be indicated in combination with the removal of the etiologic factors. Simple desensitization may be adequate, or a minimal composite restoration may be indicated. In severe cases, indirect restorative procedures with interdisciplinary long-term management is needed to control and manage the condition. In any case, keep in mind that placing a composite Page 49 of 57 restoration in the cervical area is not always beneficial to the patient in comparison with leaving as is a manageable, non-carious defect. If a composite is to be placed, treat as a normal Class V. In cervical restorations the composite should have low modulus of elasticity (e.g. flowable or microfill composite). 8.4. Enameloplasty It means elimination of a developmental fault in the remaining fissure in enamel, by removing it with the side of an appropriate shaped rotary finishing instrument, leaving a smooth surface. It is indicated when the remaining fissure is not deeper than 1/4 or 1/3 of enamel thickness. Enameloplasty reduces the need for further extension. The surface left by this procedure should meet the preparation wall of the tooth, at a cavosurface angle not more than 100 º, to reduce the margins for amalgam for not less than 80 º. Enameloplasty is many times also performed for aesthetic reasons such as making a canine look like a lateral incisor in a case with congenitally missing laterals or when rounding a canine cusp on a patient that needs to show a “softer” character through their smile, uneven incisal edges etc. When performing enameloplasty for aesthetic reason, always do that without anesthesia so at the first sign of pain you stop in order to avoid sensitivity and need for a restoration later. 8.5. Air abrasion: In EUC Dental clinic we have the AquaCare air abrasion unit. This equipment is useful for multiple purposes depending on the powder used. The indications include a range from simple stain removal (still roughens enamel), debriding pits and fissures before sealing, micromechanical roughening of surfaces to be bonded (e.g. amalgam or composite similar to micro-etching), or repaired to more aggressive procedures like tooth preparation. Always keep in mind that this is a no-contact preparation method and you do not get any haptic feeling of what you are preparing so care should be exercised. Air-abrasion tooth preparation is many times referred to as pain free Operative Dentistry or No drill Operative Dentistry as it is usually significantly more comfortable than Page 50 of 57 conventional tooth preparation, thus having great advantages in pediatric dentistry. This technique relies on transferring the kinetic energy from a stream of powder particles on tooth structure surface. Therefore, it has limitations when used to excavate caries, since the kinetic energy is absorbed by the soft carious tissue, and thus, it cannot be removed. The air abrasion has also limited usage in producing well-defined preparation margins or other details that is only possible to achieve with rotary cutting techniques. 9. Adhesive luting of indirect restorations: The cements used for cementation of fixed restorations can be temporary or definitive. We do not recommend temporary cementation for single unit restorations. The cements used for permanent cementation of indirect restorations are divided in conventional and adhesive cements. The choice of cement relies on: 1) The requirements of the material. a. Materials that can be cemented with either conventional or adhesive cements. b. Materials that have to be cemented with adhesive cements (resin cements). 2) The retentiveness of the preparation and the restoration. As a general rule, we do not recommend a stronger cement than the one needed for a specific cementation procedure. 9.1. Conventional cements Conventional cements are mainly the following: 3) Zinc phosphate cement. 4) Zinc polycarboxylate cement. 5) Glass ionomer cement. 6) Resin modified glass ionomer cement. Page 51 of 57 They are usually used to cement retentive conventional castings such as porcelain fused to metal crowns and bridges or metal inlays/onlays. Also, retentive tooth colored restorations that is indicated to be conventionally cemented (e.g. Zirconium oxide) and metal prefabricated or cast posts. More information on the use of these cements can be found in the guideline of Fixed Prosthodontics. 9.2. Adhesive cements Adhesive cements are the following: 1) Resin cements (i.e. conventional resin cements that require a bonding agent). a. Light cure resin cements. b. Dual cure resin cements. c. Self cure resin cements. 2) Self-etch/self-adhesive resin cements. 9.2.1. Resin cements (Bonding agent is required) These cements are usually used to cement all ceramic restorations that require adhesive bonding (e.g. feldspathic porcelain veneers, inlays/onlays), non-retentive conventional castings (e.g. PFM crowns), resin bonded bridges and non-retentive natural tooth colored restorations (e.g. Zirconium oxide or lithium disilicate crowns). We also usually recommend to use these cements to cement posts of any type as posts are placed in teeth that are usually marginally salvageable and the next step in case of failure is usually to extract the tooth. The technique sensitivity of these cements is high and post-operative sensitivity may happen. However, they are cements that offer the higher possible bond strength and are the only option for several cases. 9.2.2. Self-etch / Self-adhesive Resin cements (Bonding agent is not required) These cements are significantly weaker than resin cements that require a bonding agent. Their strength and indications should be compared with the conventional (non- resin) cements and they have few indications. They may offer an advantage over the conventional cements in the cementation of Zirconia restorations due to the 10-MDP that is usually contained in them. However, the strength offered with resin cements will be significantly higher than with self-etch/self-adhesive resin cements. Page 52 of 57 9.3. Pre-treatment of intaglio surfaces of indirect restorations. Pre-treatment of the intaglio surfaces of restorations is required to offer a better bond strength with less post-operative problems. 9.3.1. Microetching (sandblasting) All laboratory made restorations should be asked to be returned sandblasted from the Dental laboratory. This procedure offers a much better micromechanical retention to all materials. In many cases, we will need to microetch the restorations in the clinic with the Microetcher device and aluminum oxide 50μm powder to finalize cleaning of the temporary cement, in cases that the restoration is not sandblasted from the lab or when a e.g. metal pre-fabricated post is used. No sandblasting should happen to thin porcelain veneers and to thin margins as they may be destroyed. 9.3.2. Porcelain treatment There are etchable (silica based) and non-etchable (i.e. zirconia) porcelain materials. When adhesive luting is performed, always use a compatible to dual cure resins bonding agent and a resin cement. Also, we strongly recommend to use a dual cure bonding agent (note: dual cure compatibility and dual cure material is two different things). Etchable ceramics In this category belong materials like feldspathic porcelain, leucite reinforced porcelain and lithium disilicate porcelain. Steps to take after try-in and cleaning the restoration when delivering this type of restorations are: 1) Acid etching with Hydrofluoric acid (). 2) SIlanization. 3) Application of the bonding agent according to the manufacturer’s recommendations. Non-etchable ceramics In this category belongs mainly Zirconium oxide restorations. The cement of choice for this material, when we have retentive preps/restorations, are conventional cements or self-etch/self-adhesive resin cements. However, if more bonding strength is required, a resin cement with a bonding agent will provide significantly better Page 53 of 57 retention, provided that proper pre-treatment is followed. Steps to take when adhesively luting these types of restorations are: 1) Clean intaglio surface after try in with appropriate Zirconia cleaner such as ZirClean. If not, the 10-MDP primer will not work appropriately. 2) Place Zirconia primer (10-MDP primer). 3) Application of the bonding agent according to the manufacturer’s recommendations. Alternative to that, we can apply Tribochemical silica coating treatment to zirconia which allows acid etching with hydrofluoric acid and silanization. 9.3.3. Indirect restoration luting table The following table presents an overview of the steps to be followed during permanent cementation of an indirect restoration. Literature  Sturdevant’s Art and Science of Operative Dentistry; Andre V. Ritter, Lee W. Boushell, Ricardo Walter; 7th Edition; 2018; Elsevier Inc. St. Louis, Missouri, 63043, USA. ISBN: 978-0- 323-47833-5. Page 54 of 57  Managing Carious Lesions: Consensus Recommendations on Carious Tissue Removal; F. Schwendicke et al, 2016. Advances in Dental Research. 28(2) 58–67.  ICCMSTM Guide for Practitioners and Educators; N.B.Pitts et al, 2014. https://www.iccms- web.com/uploads/asset/592845add7ac8756944059.pdf  Light curing guidelines for practitioners. A Consensus statement from the 2014 Symposium on light curing in Dentistry held at Dalhousie University, Halifax, Canada. J.F. Roulet, R. Price 2014. J Adhes Dent.16(4) 303-304. Published simultaneously at J Adhes Dent, Dent Mater, Oper Dent, J of the Canadian Dent Assoc.  State of the art etch and rinse adhesives. DH. Pashley et al, 2011; Dent Mater (2011): 1-16.  State of the art of self-etch adhesives; B. Van Meerbeek et al, 2011. Dent Mater (2011) 17-28.  Universal dental adhesives: Current status, laboratory testing, and clinical performance. S. Nagarkar et al, 2019. J Biomed Mater Res B Part B. 2019:00B:1–11. Page 55 of 57 CLINICAL OPERATIVE DENTISTRY EVALUATION AND COMPETENCY SHEET Student Tooth Group Surfaces Date Restoration Type Instructor CATEGORY Overall Experience and Intellectual Traits, Patient and Appointment Management, Infection Control, Problem Solving, Clinical COMMENTS FACULTY STUDENT Reasoning and Integration of SCORE SCORE Relevant Scientific Evidence. Appointment Management Infection FAIL FAIL Control, Safety protocols Communication with patient, staff and faculty Time Management Confidence in reasoning Technical competence, clinical skills Cavity Preparation Retention form Outline form Resistance form Cavosurface angle, enamel support, smoothness, bevel Caries removal Existing restorative material Rubber dam isolation Page 56 of 57 CLINICAL OPERATIVE DENTISTRY EVALUATION AND COMPETENCY SHEET Student Tooth Group Surfaces Date Restoration Type Instructor CATEGORY Overall Experience and Intellectual Traits, Patient and Appointment Management, Infection Control, Problem Solving, Clinical COMMENTS FACULTY STUDENT Reasoning and Integration of SCORE SCORE Relevant Scientific Evidence. Appointment Management Infection FAIL FAIL Control, Safety protocols Communication with patient, staff and faculty Time Management Confidence in reasoning Technical competence, clinical skills Cavity Preparation Retention form Outline form Resistance form Cavosurface angle, enamel support, smoothness, bevel Caries removal Existing restorative material Rubber dam isolation Page 57 of 57