Clinical Technique Class I PDF

Clinical Technique in Direct Composite Restoration Class I  Introduction The choice of a material to restore caries lesions and other defects in teeth is not always simple. Tooth-colored materials, such as composite, are used in almost all types and sizes of resto...

Clinical Technique in Direct Composite Restoration Class I  Introduction The choice of a material to restore caries lesions and other defects in teeth is not always simple. Tooth-colored materials, such as composite, are used in almost all types and sizes of restorations. Composite materials are done with: minimal loss of tooth structure, little to no discomfort, relatively short operating time, and modest expense to the patient (compared to indirect restorations) Tooth with extensive defects and esthetics is the primary concern: best treatment option is ceramic onlay or crown  Factors affecting lifespan of a direct esthetic restoration nature and extent of the initial caries lesion or defect treatment procedure restorative material and techniques used operator skill patient factors - oral hygiene - caries risk - occlusion - adverse habits Remember: the effectiveness of generating a bond is important for the success and longevity of direct restorations → isolation of the operating field is paramount Failures can happen due to: - trauma - improper tooth preparation - inferior materials - poor material selection - patient-related risk factors Indications for composite restorations: Class I, II, III, IV, V, and VI restorations foundations and core buildups sealants and preventive resin restorations (conservative composite restorations) esthetic enhancement procedures: - partial veneers - tooth contour modifications - full veneers - diastema closures temporary or provisional restorations periodontal splinting luting of indirect esthetic restorations (flowable)  Contraindications: inability to obtain isolation occlusal considerations related to wear and fracture of the composite material if placed on occlusion/heavy occlusion ≠ composite if goal is to strengthen remaining weakened unprepared tooth → composite done with assurance that patient recall is followed timely extension of the restoration to the root surface results in a less than ideal marginal integrity operator factors committed to performing isolation procedures, if not, treatment becomes difficult and time consuming  Advantages: esthetics conservative tooth preparation - less extension - min. depth not necessary - mech. retention usually not necessary low thermal conductivity universal use adhesion to the tooth repairability  Disadvantages: poor marginal and internal cavity adaptation on root surfaces → polymerization shrinkage and/or improper composite insertion marginal deterioration over time due to absence of marginal enamel bonding more difficult and time consuming to place bonding requires multiple steps insertion more difficult establishment of proximal contacts, axial contours, embrasures occlusal contacts, finishing and polishing may be more difficult  Disadvantages: costlier (compared to amalgam) more technique sensitive proper isolation of operating site incremental placement technique proper adhesive technique should be followed exhibit greater occlusal wear in areas with high occlusal stress OR when all tooth’s occlusal contacts are on the composite INITIAL CLINICAL PROCEDURES Primary considerations: Obtain and finalize the following before scheduling the patient except for emergencies: complete examination brief review of the patient’s record (inc. medical) radiographs current caries risk (thru caries risk assessment) diagnosis treatment plan informed consent Local Anesthesia required for many operative procedures profound anesthesia → more comfortable and uninterrupted procedure → less salivation Operating Site Preparation clean the operating site with a slurry of pumice to remove plaque and superficial stains calculus removal is a must prophy pastes containing flavoring agents, glycerin, or fluorides must not be used if composite restoration is to be done after acts as contaminants compromises the adhesion procedure  Shade Selection Proper shade selection should be accomplished for all direct composite restorations. Shade should be determined before teeth are subjected to any prolonged drying - dehydrated teeth is lighter in shade - due to a decrease in translucency secondary to water loss form a naturally porous tooth  Shade Selection Reminders: 1. Teeth to be matched must be clean. 2. Remove bright colors from the field of view. ✓ makeup/tinted eye glasses ✓ bright gloves ✓ neutral operatory walls 3. View patient at eye level 4. Evaluate shade under multiple light sources  Shade Selection 5. Make shade comparisons at the beginning of appointment. 6. Shade comparisons should be made quickly to avoid eye fatigue.  Isolation of the operating site is critical and fulfilled with rubber dam, an isolation device (Isolite), or cotton rolls and cellulose wafers.  Isolation of the operating site Regardless of the method, isolation is imperative if a successful adhesion is to be obtained. contamination of etched enamel and dentin by saliva → decreases bond strength contamination of the composite material during insertion → degradation of the physical and mechanical properties Other Preoperative Considerations Identify occlusal contacts of the tooth or teeth to be restored, and occlusal contacts on adjacent teeth. WHY? 1. to plan the restoration outline form → preventing an area with direct occlusal contact on the cavo-restoration interface 2. to establish the proper occlusal contact on the restoration Remembering where the contacts are located on adjacent teeth provides guidance in knowing when the restoration contacts are correctly adjusted.  TOOTH PREPARATION General rules for direct posterior composite 1. create access to the faulty structure 2. removal of faulty structures ✓ caries lesion ✓ defective restoration ✓ base material, if present 3. create convenience form for the restoration When placing most posterior composites, it is not necessary to incorporate mechanical retention features in the tooth preparation, as it is obtained primarily by bonding.  TOOTH PREPARATION 5 designs of tooth preparation for composite restoration: conventional beveled conventional modified box only slot preparation  Small to moderate Class I use minimally invasive tooth preparations don’t require typical resistance and retention form features conservative preparations → more flared cavosurface forms without uniform or flat pulpal or axial walls initial depth → determined only by selective removal of carious tooth structure no minimal thickness of restorative material to limit bulk fracture  Small to moderate Class I prepared with a small round or elongated pear-shaped diamond or bur with round features → for the sake of conservation size and shaped of instrument dictated by → size of lesion or defect, or type of defective restoration being replaced if round instrument is used → resulting csm angle is more flared (obtuse) than if an elongated pear-shaped instrument is used  Small to moderate Class I both carbide and diamond instruments can be used diamond instruments leave a thicker smear layer → raising concerns about self- etching adhesive systems to adequately reach and etch the underlying tooth structure BUT clinical trials show an excellent performance of mild-etch adhesive systems → not much of a concern  Moderate to large Class I large carious lesions or replacing amalgam restorations typical features of an amalgam restoration: flat walls that are perpendicular to occlusal stress strong tooth and restoration marginal configurations All of these features help resist potential fracture in less conservative tooth preparations.  Moderate to large Class I preparation should never be excessively extended beyond removal of faulty structures to justify resistance and retention forms → further weakens the tooth structure → failure of the tooth restoration unit if occlusal portion of the restoration is expected to be extensive → use elongated pear-shaped cutting instruments with round features → results in strong 900 csm without creating sharp internal line angles  Moderate to large Class I box-like prep from for extensive preps → increases the negative effects of the cavity C-factor OBJECTIVE of tooth preparation → remove all carious tissues or fault as conservatively as possible WHY? → composite is bonded to the tooth structure, other less involved or at-risk areas can be sealed as part of the conservative preparation techniques  Procedure tooth is entered in the area most affected by the carious lesions → using an appropriate diamond or bur (either round or pear-shaped with round end positioned parallel to the long axis of the crown Procedure when preparation of the entire MD length of the central groove is anticipated → enter the D first then traverse M’ly along the central groove in a controlled manner → better operator visibility during preparation, and → follows the rise and fall of the DEJ → if to be extended toward the cusp tips, same depth of approx. 0.2mm inside the DEJ is maintained Procedure → preparation is then extended F’ly, Li’ly, M’ly, and D’ly as indicated at the depth of the carious DEJ UNTIL a caries-free DEJ is identified → M, S, F, and Li extensions dictated by: - caries lesion - defect - old restorative material → always use the DEJ as a reference for both extensions and pulpal depth → AVOID unnecessary extension into cuspal and marginal ridge areas → tooth strength compromised  Procedure pulpal floor initial depth → approx. 0.2mm internal to the carious DEJ  Procedure flat pulpal floor with an initial preparation depth of 1.5mm to 2mm is also acceptable  Procedure final outline form should be as conservative as possible extensions into the marginal ridges should result in at least: → 1.5mm for premolars → 2.0mm for molars These help preserve the dentinal support of the marginal ridge and cusp tips → improves overall ability of tooth to resist occlusal forces. Procedure  Procedure same uniform depth concept applicable when extending a F or Li groove radiating from the O surface when groove extension is through the cusp ridge, instrument prepares the F (or Li) portion of the faulty groove at an axial depth of 0.2 mm inside the DEJ and G’ly to include all caries and other defects  Procedure after extending the outline form to sound tooth structure, if there are caries or old restoration on the pulpal floor, remove it with an appropriately sized round bur or excavator do not bevel the occlusal margin → doing so may enlarge the isthmus of the preparation Procedure RESTORATIVE TECHNIQUE Placement of the Etchant various concentrations of H3PO4 have been used to etch enamel 30% - 40% are current acid gel concentrations, with 37% as the most common a 15-20-second enamel etch resulted in a surface roughness similar to that provided by a 60-second etch shear bond strength = exceed 20 MPa ranging up to 53 MPa → provide adequate retention and prevent microleakage around enamel margins of restorations RESTORATIVE TECHNIQUE Placement of the Adhesive acid-etching transforms smooth enamel into an: irregular surface increases surface-free energy when a fluid resin-based material (adhesive) is applied to the irregular surfaced enamel → resin penetrates into the surface when polymerized, material becomes interlocked with the enamel surface → resin tags → fundamental in the resin- enamel adhesion RESTORATIVE TECHNIQUE Placement of the Adhesive apply dental adhesive to the entire preparation with a microbrush after etching and washing after application, polymerize with a light-curing unit always follow manufacturer’s instructions  RESTORATIVE TECHNIQUE Pulp Protection if tooth preparation is judged to be near the pulp in vital pulp, pulp protecting agents are to be placed prior to etching RDT 0.5 and 1.5mm → GIC or RMGIC + e + b RDT