Maxillary and Mandibular Class III Cavity Preparation and Restoration (TC1)

Transcription

1 Maxillary and Mandibular Class III Cavity Preparation and Restoration (TC1) Instruments 1. Dental mirror 2. Explorer/probe 3. Cotton forceps 4. Low and high speed handpieces 5. High speed burs #½, 1, 2 round bur, MFS finishing burs #329, #7901, # Low speed #½, 2 round bur 7. Dycal applicator 8. Burnisher No. 1A/B 9. Plastic #6 Materials 1. Composite resin (Filtek SupremeTMXT) 2. LC Vitrebond 3. Interproximal wooden wedge 4. Celluloid matrix strip 5. 3M interproximal finishing strips 6. Dental Floss If necessary, the tooth is cleansed with pumice before shade selection. The shade is matched using the VITA shade guide and the Filtek Supreme Shade Selector Wheel. The tooth is prepared under rubber dam clinically. 1. Outline form a. The maxillary Class III preparation is normally done by a lingual approach to preserve labial enamel for esthetics. Draw an outline form of a "tear drop" shape on mesial or distal palatal surface of the tooth Figure 4 - Palatal outline form of cavity

2 b. The mesial margin should begin in the contact area inciso-gingivally. c. Preparation width - the mesial-distal width (axial depth) of the preparation should approximate 1.5mm. d. Preparation length - the incisal gingival length of the preparation should approximate mm depending on which tooth.(generally, it should not exceed more than 1/3 of the crown height). The incisal extension should include 1/2 of the contact area. e. Labial extension - the labial extension should be almost invisible and just short of the contact point labially (Fig. 5). Figure 5 - Proximal outline of Cavity f. Remember that caries usually occur at the PROXIMAL contact point, or slightly below the contact point. Therefore, the outline form should occupy most of the proximal surface and there should be minimal destruction of the palatal surface. 2. Angulation of walls a. Rounded line angles will create a gentle curve which harmonizes with the natural contour of the tooth. b. All walls of the cavity preparation should form a 90 degrees angle when joining the external surface of the tooth at the cavosurface. c. Only place bevels on enamel cavosurface margins if: i. the bevels placed will not be in occlusion with the opposing teeth ii. iii. there is sufficient enamel present (especially gingivally) However, for this technique exercise, you will assume that all conditions are favourable for placement of bevels. With a high speed #7901 needle shape bur, place 45 degree 1/2 mm bevels on the palatal gingival and incisal enamel cavosurface margins (where accessible). 3. Burs and instrumentation a. #1/2 round bur for initial penetration. Bur is directed 45 degrees interproximally initially and straightened. (Fig. 3) Plane of proximal surface, directing the bur interproximally labially. This is to prevent unnecessary destruction of palatal surface. Figure 3 - Initial penetration with round bur interproximally

3 b. #329 and #330 to establish outline form. Take the bur facially into the preparation. Extend outline inciso-gingivally, keeping within pencil marks. c. Place axial wall just into dentine, about 1.5mm from proximo-incisal margins. d. Develop walls at the gingival, axial, incisal and facial. e. Visualize preparation as being small and forming a trapezoidal shape as viewed from proximal, with the base located palatally and apex facially. f. Smoothen walls with gingival margin trimmer. Place a bevel 0.5 mm wide, with a flame finishing bur, on the accessible cavosurface margins (palatally, incisally and gingivally). (Fig.7) RESTORATION OF CL III COMPOSITE RESIN (Closed Sandwich Technique WITH GIC LINER) 1. Mix GIC liner (a level scoop of Vitrebond powder with Vitrebond liquid on a mixing pad. Apply a thin layer to all dentine surfaces. Light cure for 30 seconds. (*Cavity preparation). 2. Apply etchant to enamel for 15 seconds, rinse for 15 seconds and gently dry the cavity.*. 3. Apply adhesive to enamel Place mylar strip and light cure for 10 seconds. Place wedge from lingual surface. 4. Place CR (Filtek Supreme body shade) into the cavity in increments if > 2mm. Use a burnisher/plastic #6 to push CR into the cavity and add slight excess. 5. Pull the strip tightly and ensure an excess is extruded from all surfaces. Cure for 40 seconds. 6. Polish and finish the * (Finishing of restoration) Use MFS diamond finishing burs with water for gross finishing followed by different grades of Solfex discs if applicable. Use Enhance polishing disk/cone/cup as appropriate. Proximal areas can be finished using interproximal finishing strips and/or scapel with blade #12 (BE CAREFUL take care not to injure your patient or yourself!). Polishing pastes carried on a prophylaxis cup can be used to provide a final finish/ gloss to the In the clinical situation, eccentric and centric occlusal contacts should be checked. * Stages to be checked by instructor.

4 Palatal view of a Restored CL III Lesion Mandibular CL III Composite Resin Preparation Primary Restoration 1. Outline form

5 a. The mandibular Class III preparation is normally done from a lingual approach. b. Preparation width - the mesial-distal width (axial depth) of the preparation should approximate 1mm. c. Preparation length - the incisal gingival length of the preparation should approximate 1.5mm. d. Incisal extension - the incisal extension should be determined by the extent of the decay or just involve the contact point. e. Labial extension - the labial extension of the preparation (labio-lingual depth) should be minimal as access to the proximal is very convenient. 2. Angulation of walls a. All walls of the cavity preparation should form a 90 degree angle when joining the external surface of the tooth at the cavosurface. b. All enamel cavo-surface margins are modified with a 45 degree 1/2 mm enamel bevel. 3. Burs and instrumentation - similar to those used for the maxillary teeth a. #1/2 round bur for initial penetration #329 to establish outline form b. Smoothen walls with gingival margin trimmer. c. Use a flame finishing bur to instrument and to provide a 1/2 mm bevel at all accessible cavo-surface margins RESTORATION OF CL III COMPOSITE RESIN (TOTAL ETCH TECHNIQUE) 1. No liner is placed on the dentine. 2. Apply etchant to enamel and dentine for 15 seconds, rinse for 15 seconds and blot dry the cavity. Leave moist. 3. Apply primer to enamel and dentine (no waiting). Gently air dry to evaporate the solvent. Surface will appear shiny. 4. Apply adhesive to enamel and dentine. Place mylar strip and light cure for 10 seconds. Place wedge from lingual surface. 5. Place CR (Filtek Supreme body shade) into the cavity in increments if > 2mm. Use a burnisher/plastic #6 to push CR into the cavity and add slight excess. 6. Pull the strip tightly and ensure an excess is extruded from all surfaces. Cure for 40 seconds. 7. Polish and finish the * (Finishing of restoration) Use MFS diamond finishing burs with water for gross finishing followed by different grades of Solfex discs if applicable. Use Enhance polishing disk/cone/cup as appropriate. Proximal areas can be finished using interproximal finishing strips and/or scapel with blade #12 (BE CAREFUL take care not to injure your patient or yourself!). Polishing pastes carried on a prophylaxis cup can be used to provide a final finish/ gloss to the In the clinical situation, eccentric and centric occlusal contacts should be checked. * Stages to be checked by instructor.

6 Palatal view of a Restored CL III Lesion (Total Etch Technique) Department of Restorative Dentistry Faculty of Dentistry

7 CLASS IV COMPOSITE RESIN PREPARATION(TC2) 1. Simulating a Class IV Class IV preparation has no typical outline. It can be caused by decay or trauma. The dentist must utilize the remaining tooth structure for resistance and retention as best as he can. For this exercise, a simulated fracture involving the incisal angle is carried out as illustrated in the manual. * The model is now placed in the patient simulator All enamel margins should be instrumented and smoothened. Sand paper discs may be used for the labial and lingual walls. * Placement of retention A bevel 1.5 mm in width is placed at the cavosurface enamel margins. If more retention is required, 2 retention points are placed in the gingival axial angles with a small round bur ( #1/4 round ) or a gingival groove may sometimes substitute for the 2 points. The third retentive point is placed at the expense of the axial wall just below the DEJ of the incisal edge. *In cases where the incisal angle loss is slight, a wide bevel will suffice for retaining the restoration. Instruments 1. Mouth mirror 2. Straight probe 3. Cotton forceps 4. F.G. burs #7901, 1411, MFS finishing burs. 5. Sandpaper disc mounted in mandrel. 6. Soflex discs 7. Dycal applicator 8. Rubber dam instruments 9. Articulating paper 10. Miller's forceps 11. Plastic #6 Materials 1. Filtek SupremeTMXT (Enamel, Dentine) 2. 37% phosphoric acid 3. Scotchbond Multi Purpose 4. L C Vitrebond 5. Plumber s tape Technique 1. Simulate a fractured tooth due to incisal wear or trauma at one corner of the tooth (MI or DI) with #1411 bur. Check with supervising staff.

8 2. With a sandpaper disc remove sharp edges and establish precise margins. 3. Ensure gingival and proximal contacts are cleared. 4. Place a 45 degree bevel at all accessible cavosurface margins. Bevels should be 0.5mm deep, 1.5mm wide scallop shape and totally in enamel. Use #7901 with light brushing motion and reduced speed.

9 2. Preparing an indirect template Clinical In the clinical situation, a sectional impression of the tooth in question and 2 teeth on either side is made with alginate ( use a sectional tray or a perforated whole arch tray but confine the material to the relevant teeth). Pour the impression in green stone Wax up the tooth to its ideal form ( contour, alignment from labial, palatal, proximal and incisal views and compare with the contralateral tooth ) with inlay wax. * Make an impression of the built- up tooth and 1-2 teeth on either side with addition silicon putty. * Cut the putty across the incisal exposing a labial and palatal half. Retain the palatal half and check that it fits the model and more importantly fits the tooth with the Class IV. Preclinical Simulation For this technique, the model with the fractured Cl IV tooth will simulate the laboratory study model ie steps #1 and #2 for Clinical will not be done and you can proceed to step #3. 3. Building the Class IV restoration Remove the inlay wax and place the model back into the simulator. Clean the tooth with pumice on a rubber cup. Select the shade of the tooth using the Vita shade guide provided. Proceed to the colour wheel to pick 2 shades ( usually 1 dentine and 1 enamel shade ) * Place a RMGIC liner ( eg Vitrebond ) if the dentine is deeper than 0.5 mm. * Put a piece of plumber s tape on the relevant adjacent tooth. Place the etching gel on the prepared surfaces for 15 seconds. Rinse (15 secs ) and blot dry. * Apply the primer with a microbrush if there is exposed dentine. Blow dry gently after 10 seconds. Place a layer of the adhesive, blow gently, repeat and light cure. Align the palatal template onto the dentition.

10 Using the flat plastic #6 ( Hu Friedy ), place a thin layer of CR ( Filtek Supreme Enamel Shade ) onto the template ensuring that it adapts closely to the margins. Light cure for 20 seconds from the labial surface. Remove template and cure for 20 seconds from the palatal surface. * Add the CR in layers simulating the dentine and enamel. Each layer must not be more than 2 mm thick and it should be cured for 40 seconds. Overcontour the restoration slightly to allow for finishing procedures. *This is the best stage to add resin if there is a bubble, deficiency, undercontour, etc. Polish and finish the * Use MFS diamond finishing burs with water for gross finishing followed by different grades of Soflex discs. Use Enhance polishing disk /cone/ cup as appropriate. Proximal areas can be finished using interproximal finishing strips and /or scapel with blade #12 ( BE CAREFUL take care not to injure your patient or yourself! ) Polishing pastes carried on a prophylaxis cup can be used to provide a final finish /gloss to the In the clinical situation, eccentric and centric occlusal contacts should be checked. * Stages to be checked by instructor Department of Restorative Dentistry Faculty of Dentistry

11 TC3 NCCL CAVITY PREPARATION FOR GLASS IONOMER CEMENT NCCL CAVITY PREPARATION FOR COMPOSITE RESIN CLASS V COMPOSITE RESIN RESTORATION RESTORATION OF NCCL CAVITIES WITH GLASS IONOMER CEMENT BASIC PROCEDURES FOR PLACEMENT OF GLASS IONOMER CEMENTS (FOR RESTORATIVE PROCEDURES I & II) RESTORATION OF NCCL CAVITIES WITH COMPOSITE RESINS (THE SANDWICH TECHNIQUE) RESTORATIVE PROCEDURE III (CR WITH TYPE II RESTORATIVE GIC) RESTORATION OF NCCL CAVITIES WITH COMPOSITE RESIN (Z100) RESTORATIVE PROCEDURE IV (CR WITH DENTINE BONDING SYSTEM) RESTORATION OF NCCL CAVITIES WITH DYRACT COMPOMER SUMMARY ON RESTORATION OF NCCL CAVITIES Non Carious Cervical Lesion (NCCL) CAVITY PREPARATION FOR GLASS IONOMER CEMENT In the clinical situation, you will not be required to make such a preparation as the patient will present with NCCL lesions. However for your projects involving the use of glass ionomer cement (chemical and light cured) and the sandwich technique, you will be required to prepare simulated cervical erosion/nccl lesions. Burs # Remove stone labial to the tooth, 4mm below the CEJ. 2. Notch the facial surface at the cervical line with bur #1311 (diamond straight fissure).it should extend mesio-distally to simulate cervical NCCL. Notch should be no more than 3mm occlusogingivally, 4mm mesiodistally and 1.5mm axially.

12 NCCL CAVITY PREPARATION FOR COMPOSITE RESIN 1. The dimension and procedure of cavity preparation is the same as that for GIC NCCL cavity. 2. The only difference in the cavity preparation to be restored with CR is that a 45 degree bevel of >0.5mm width is placed on the occlusal enamel cavosurface margin only. CLASS V COMPOSITE RESIN RESTORATION Composite resin is used in Class 5 locations when esthetics is very important. The introduction of dentine bonding agents have improved the seal of the composite resin with a margin in dentin or cementum. However, the seal does not equal that of an amalgam or when all its margins are in enamel. For this reason, a Class V composite resin is not usually done unless dictated by esthetics. The shape of a Class V composite resin restoration is determined by the extent of caries, so its shape will vary from situation to situation. The shape of a Class V restoration should be determined by the caries and decalcification which the preparation has removed, so the outline can take on any form. Note the following situations. 1. When caries extends into dentine, the preparation should remove caries and it may extend into dentine. 2. If adequate enamel is present on the margin of a Class V preparation, bevel the enamel which is usually present at

13 the incisal margin. 3. The cervical margin usually lies in dentine and a bond to etched enamel is not possible. Retention at this site could include the following: i. the use of a dentine bonding agent ii. mechanical retention using a groove placed at this site or both (i) and (ii) Location of Class V preparation a. Both incisal and gingival margins in enamel - bevel both with etched enamel and enamel bonding agent, no grooves are needed. b. Preparation below CEJ with no enamel margins, do not bevel; dentine bonding agent (DBA) is required. c. Preparation with sufficient enamel to bevel at incisal margin but insufficient enamel to bevel at the gingival margin; DBA should be used. A groove may sometime be necessary for additional retention at the cervical 3 dimensional diagram showing a typical Class V preparation with the incisal margin (beveled) in enamel and the gingival margin and cementum; a groove is placed at the gingivo-axial line. Note bevel on incisal margin tapers out as it approaches the CEJ. Composite resin is inserted and polymerised in small increments to minimize effects of polymerization shrinkage.

14 A suggested arrangement of increments in placing composite resin into a Class 5 preparation. Increment location will vary with the shape and depth of the preparation. Increments should be small.if bulk placement is employed as opposed to incremental placement, polymerization shrinkage will open dentin-to-resin margins even if a DBA has been used. Finishing of the resin includes the use of a #12 scapel blade and Sof-lex discs. RESTORATION OF NCCL CAVITIES WITH GLASS IONOMER CEMENT Fuji II LC GC Powder : Fluoro-alumino-silicate glass Liquid : Polyacrylic acid HEMA (hydroxy ethyl methacrylate) photopolymerization initiator Setting mechanism (light cure) Dual cure : 1. Acid and base (powder + liquid) 2. HEMA ----> poly-hema visible light Dentin conditioner : 10% polyacrylic acid 1. removal of smear layer without opening of dentinal tubules 2. improve adhesion to dentin BASIC PROCEDURES FOR PLACEMENT OF GLASS IONOMER CEMENTS (FOR RESTORATIVE PROCEDURES I & II) 1. NCCL/Erosion/Non Carious Cervical Lesions

15 1. Prophylaxis Cleanse the tooth with a rubber cup and non fluoridated polishing paste. 2. Shade selection This should be accomplished before any cavity preparation is carried out. 3. Isolation Rubber dam is not necessary for placement of GIC as it is a water-based reaction. However the use of cotton roll isolation should ensure that the cavity area is free from excess surface moisture or salivary contamination but not dehydrated before placement of the material. 4. Dentin conditioning Placement of polyacrylic acid (10% solution) should be used at all times for a period of 20 seconds. Rinse for 20 seconds and dry. 5. Proportioning and mixing (check manufacturer's instructions) Mixing ratio - 1 spoonful powder (Fuji II LC): 2 drops of liquid (light cure) 6. Placement and shaping Place the cement either with a syringe or plastic instrument. Insert the material immediately after it has been mixed to allow contact with the tooth surface. Ensure that the surface of the GIC is still glossy. a. Chemically cured resin Place either a burnished matrix or paint a layer of unfilled resin over the surface of the restoration b. Light curing It should be carried out as quickly as possible to prevent any possibility of moisture contamination Cure for a minimum of 40 seconds for a 2mm thickness of resin The chemical part of the reaction is completed after 9 minutes. 7. Protection For chemically cured materials, apply a layer of unfilled/bonding resin to the surface of the restoration and light cure for 20 seconds. 8. Polishing a. This may be carried out on the same visit for a LC GIC. For a chemically cured resin, polishing is carried out at another visit. b. Remove gross excess with fine diamond or 12 fluted TC burs c. Use water spray liberally d. For finishing, use the Soflex polishing discs e. Complete the procedure with the use of polishing paste or Enhance polishing kit. 9. Final protection Coat the restoration with a layer of unfilled resin and light cure for 20 seconds. 2. Cavity preparation required (eg when caries is present) 1. Remove carious lesion 2. Deep cavities should be lined with a layer of calcium hydroxide in the deepest portion of the axial/gingival wall. It must not interfere with GIC bonding.

16 3. Select matrix if required and adapt it by burnishing over the cavity preparation. 4. Apply a 10% polyacrylic acid solution for 20 seconds to ensure effective cleaning and wetting of substrate surfaces. Wash copiously with water for 20 seconds. 5. Mixing of GIC (Refer to attached notes) 6. Follow steps RESTORATION OF NCCL CAVITIES WITH COMPOSITE RESINS (THE OPEN SANDWICH TECHNIQUE) RESTORATIVE PROCEDURE III (CR WITH TYPE II RESTORATIVE GIC) 1. Prophylaxis. 2. Shade selection. 3. Cotton roll isolation. 4. Apply 10% polyacrylic acid solution on dentine x20 seconds. Wash copiously with water x20 seconds and dry (not excessively). 5. Place type II restorative GIC (eg. Fuji II LC) on dentine. The material should extend to the gingival dentine cavosurface margin of about 1mm thickness to form part of the CR restoration. Light cure for 40 seconds. 6. Etch bevelled enamel only for 20 seconds. Do not place acid on the GIC. 7. Wash and dry etched enamel. 8. Place a layer of unfilled resin, thin out and cure. 9. Place CR and cure (cure in layers if cavity is large and deep). 10.Finish the restoration with soflex discs or Micron Finishing System (MFS) burs. RESTORATION OF NCCL CAVITIES WITH COMPOSITE RESIN RESTORATIVE PROCEDURE IV (CR WITH DENTINE BONDING SYSTEM) 11.Prophylaxis.

17 12.Shade selection. 13.Cotton roll isolation. 14.Bevel the enamel. 15.Etch, wash and blot dry the cavity. 16.Apply primer and adhesive to the cavity (following the manufacturer's instructions), thin out adhesive and cure. 17.Place CR in 2 increments. Cure first increment gingivally for 40 seconds then add second increment and cure for 40 seconds. 18.Finish the CR as usual. Back to Top RESTORATION OF NCCL CAVITIES WITH DYRACT COMPOMER 1. Prophylaxis 2. Shade selection 3. Cotton roll isolation 4. Etch the cavity preparation for 20 seconds. Rinse and blot dry. 5. Apply Prime&Bond 2.1/NT and leave it undisturbed for 30 seconds. 6. Remove excess solvent with air syringe 7. Light cure for 10 seconds. 8. Apply a second layer of Prime&Bond 2.1/NT and air dry solvent immediately. 9. Light cure for 10 seconds. 10.Insert the compomer and light cure for 40 seconds.(if the cavity is deeper than 3 mm, insert the compomer incrementally; i.e cure the gingival portion first, followed by the occlusal portion, each for 40 seconds) 11.Finish the compomer using the micron finishing system (MFS) burs, enhance polishing system, or soflex discs.

18 Back to Top SUMMARY ON RESTORATION OF NCCL CAVITIES Cavity Design Restorative Material Restorative Procedures Wedge Shaped (I) Chemical Cure GIC See notes for details (3 mm occlusogingivally 4 mm mesiodistally, 1.5 mm axially) 1. Prophylaxis 2. Shade selection 3. Cotton roll isolation 4. Dentine conditioning 5. Mixing and placement of material. Matrix placement 6. LC unfilled resin protection 7. Remove excess 8. Polishing at next visit 9. Final protection with LC unfilled resin (II) Dual cure GIC 1. Prophylaxis 2. Shade selection 3. Cotton roll isolation 4. Dentine condition

19 5. Mixing and placement of material. Matrix placement 6. Light cure the material 7. Finishing can be commenced after 10 minutes or more 8. Final protection with LC unfilled resin Wedge Shaped (3 mm occlusogingivally 4 mm mesiodistally, 1.5 mm axially) but occlusal ENAMEL cavosurface is BEVELLED (III) Composite resin with restorative type II GIC (The "SANDWICH" TECHNIQUE) 1. Shade selection 2. Prophylaxis 3. Cotton roll isolation 4. Dentine conditioning 5. Type II GIC on dentine only. The gingival part of the restoration is in GIC 6. Etch, wash, dry enamel 7. Apply unfilled resin and cure 8. Place composite resin and cure 9. finishing Cavity is not very deep, just into dentine. (Bevel placed in enamel cavosurface margin) (IV) Composite resin with dentine bonding system 1. Prophylaxis 2. Shade selection 3. Cotton roll isolation 4. Bevel enamel 5. Etch, wash and dry enamel 6. Prime dentine 7. Apply adhesive and cure 8. Apply composite resin in 2 increments and cure each increment for 40 seconds

20 FISSURE SEALANT (TC4) Condition Of extracted teeth Deep, complicated grooves. May be stained but not carious Instruments 1. Rubber dam armamentarium 2. mouth mirror, straight probe, cotton forceps 3. Miller's forceps 4. Prophy brush 5. Composite finishing kit Materials 1. Fissure sealant :UltraSeal XT plus and PrimaDry (99% Ethyl Alcohol) 2. 35% phosphoric acid :Ultra-Etch 3. Articulating paper 4. Pumice powder and water slurry Technique 1. Isolate the teeth with rubber dam. 2. Remove any calculus or debris in the pit and fissure with probe but do not jam the probe into the fissures.

21 3. Etch the fissure system for 15 seconds, then wash with air/water spray and blow dry. 4. Apply PrimaDry and leave for 5 seconds. Dry by gently blow (make sure that the air from triple function syringe is moisture-free) 5. Express a small amount of resin through the inspiral brush tip. Move the brush along the fissures until all fissures are covered with thin layer of sealant. Ensure that the sealant flows evenly into all fissures without entrapping any bubbles. Light cure for 20 seconds.

22 6. Check retention of the sealant by trying to pry the margin with a probe 7. Remove rubber dam and check occlusion 8. Remove any high spot with composite finishing point/cup (Enhance polishing system). Department of Restorative Dentistry Faculty of Dentistry

23 PREVENTIVE RESIN RESTORATION (PRR)(TC5) Condition of extracted teeth Initial isolated carious lesions just into dentine with a complicated but caries-free fissure system. Instruments 1. Rubber dam armamentarium 2. mouth mirror, straight probe, cotton forceps 3. Pear shaped 331 carbide bur 4. Small round bur 5. Spoon excavator 6. Dycal applicator 7. Plastic instrument 8. Miller's forceps 9. Prophy brush 10.Composite finishing kit Materials 1. Posterior composite resin 2. Bonding system 3. Glass ionomer lining cement (Vitrabond) 4. Fissure sealant :UltraSeal XT plus and PrimaDry (99% Ethyl Alcohol) 5. 35% phosphoric acid (Ultra-Etch ) 6. Articulating paper 7. Pumice powder and water slurry Technique 1. Isolate the teeth with rubber dam. 2. Remove any calculus or debris in the pit and fissure with probe but do not jam the probe into the fissures. 3. When caries is suspected and further investigation is needed, use small round bur (1/4 round bur) to widen the fissure in order to detect caries first. 4. If caries is present and extend to dentine, use high speed #331 bur to gain access. 5. Remove caries and softened dentine with spoon excavator or slow speed round bur (Staff check). 6. Mix and place light cure glass ionomer cement (Vitrabond) in deep cavity, then light cure for 30 seconds. Powder 1 Scoop Liquid 1 Drop Mix Seconds Working Time 2 Minutes 40 Seconds Remove any excess from enamel 7. Etch the cavity and the entire fissure system for 15 seconds, then wash with air/water spray, blow dry.

24 8. Apply a thin layer of primer into the cavity and gently blow dry. 9. Apply bonding resin to the cavity and light cure for 10 seconds. 10.Fill the cavity with composite resin and light cure for 40 seconds. Composite should be filled in incremental layer. 11.Apply PrimaDry on the rest of the fissure and leave for 5 seconds. Dry by gently blow (make sure that the air from triple function syringe is moisture-free). 12.Express a small amount of resin through the inspiral brush tip. Move the brush along the fissures until the entire fissures are covered with thin layer of sealant. Ensure that the sealant flows evenly into all fissures without entrapping any bubbles. Light cure for 20 seconds. 13.Check retention of the sealant by trying to pry the margin with a probe. 14.Remove rubber dam and check occlusion. 15.Remove any high spot with composite finishing point/cup (Enhance polishing system). Department of Restorative Dentistry Faculty of Dentistry

25 CLASS I AND CLASS II POSTERIOR COMPOSITE RESIN OPERATIVE TECHNIQUE (TC6) Condition of extracted teeth Teeth should be free of any caries and restorations. There will not be a demonstration on the cavity prepartion for posterior composite. Demonstration models are available on the front desk. NB : The Cl I cavity preparation for 47 and Cl II (mo) cavity preparation for 46 should have been marked before this demonstration session, ready for the placement of posterior composite resin. Instruments required for posterior CR placement 1. PKT No. 3A/B 2. Rubber dam instruments 3. Mouth mirror, straight and sickle probes 4. Dycal applicator 5. Burnisher No. 1A/B 6. Condenser 8A/B 7. Tofflemire matrix retainer 8. Bard parker with blade Articulating paper 10. Miller's forceps 11. Floss 12. Interproximal finishing strip (fine) Materials required 1. GIC lining material (L C Vitrebond) 2. Posterior CR (Filtek Supreme Z350) 3. Hawe light reflecting Luci wedges and preformed transparent matrix band or 3M sectional matrix and wooden interdental wedge 4. Light cure unit 5. 37% phosphoric acid etchant 6. Unfilled bonding resin TECHNIQUE Cl I POSTERIOR CR STAFF : PLEASE CHECK THE CAVITY PREPARATIONS FIRST 1. Mix Vitrebond GIC for seconds (1 scoop of powder to 1 drop of liquid). Cover all exposed dentine with GIC with Dycal applicator. 2. Place GIC on pulpal floor covering dentine only. Thickness of GIC = 0.5mm Light cure 30 seconds (STAFF CHECK) 3. Etch enamel only for 30 seconds, wash 30 seconds, dry 30 seconds. 4. Apply unfilled bonding resin, thin out with air, cure 20 seconds increments for Cl I restoration. Increment 1 : Buccal and pulpal walls

26 Carry some CR on a flat plastic to the buccal cavosurface margin. Leave CR for several seconds before placement on tooth. CR obtains a gloss and sticks better to tooth (and thereby less to the instrument). Lightly tap, "puddle" and spread using clean amalgam packers and flat plastic instruments along the buccal (or lingual walls) and pulpal wall. CR becomes less viscous and is adapted to walls, line angles and margins. Take care to avoid trapping air in the line angles (Fig.1). Cure from buccal direction for 40 seconds (STAFF CHECK). Increment 2 : Lingual wall and occlusal surface Apply second increment of CR to the rest of the cavity, adapt and seal composite to margin. Carve (contour) the restoration with PKT No 3A/B as well as you can before curing. Cure from lingual direction for 40 seconds (STAFF CHECK). 6. Check occlusion 7. Remove high spots and finish the restoration with diamond finishing burs, Enhance polishing disks or points; followed by Prisma Gloss (a fine aluminium oxide past) applied with a rubber cup. Department of Restorative Dentistry Faculty of Dentistry

27 CL II CAVITY (5 INCREMENTS) CLOSED SANDWICH TECHNIQUE (TC7) 1. Mix and apply GIC Vitrebond on the pulpal and axial wall (» 0.5mm thick) and cure. 2. Etch all enamel with 37% phosphoric acid for 15 seconds, wash 15 seconds, blot dry. 3. Apply unfilled bonding resin, thin out, place a thin mylar strip, cure for 20 seconds. 4. Place a sectional matrix, a wedge and secure this with a G-ring. 5. CR Placement Proximal CR placement (Figure 2) Increment 1 : Place 0.5mm of CR on gingival floor Cure : i. along light reflecting wedge for 20 seconds ii. from occlusal 20 seconds (STAFF CHECK) Increment 2 : Place CR on buccal wall and gingival increment Cure : iii. iv. at buccal margin for 20 seconds from occlusal for 20 seconds (STAFF CHECK) Increment 3 : Place CR on lingual wall, restore marginal ridge Cure : v. at lingual margin for 20 seconds vi. from occlusal for 20 seconds (STAFF CHECK)

28 a. Remove matrix and wedge. This enables better contouring of the occlusal part. Cure the gingival portion of the restoration for an additional 30 seconds. b. Occlusal CR (same as Cl I CR placement) (Figure 3) Increment 4 : Buccal and pulpal wall, cure 40 seconds Increment 5 : Lingual wall and restore occlusal form. Adapt and seal, as described previously. Cure 40 seconds (STAFF CHECK) If deficiency is detected, add more composite resin before any grinding of the surface is commenced. 6. Check occlusion. 7. Finish the restoration with diamond finishing burs and Enhance polishing disk or points as appropriate followed by Prisma Gloss (a fine aluminium oxide paste) applied with a rubber cup. Department of Restorative Dentistry Faculty of Dentistry