Australasian Dentist Magazine March April 2021

Category 66 Australasian Dentist P redictability of establishing firm and anatomic contacts has been a complication of direct restorative dentistry since the introduction of composite resins and the inability to pack and laterally displace material similar to the properties of amalgam. Tofflemire- type matrix systems are circumferential, however feature axial emergence profiles that are unnaturally straight and difficult to modify to generate curved, anatomic profiles even with determined burnishing. The Garrison Slick band architecture features a moderate, average curve, a great compromise between one with a more pronounced proximal convexity, such as the Triodent/Palodent Sectional matrix systems and one without any convexity at all. This allows fitment in narrow proximal areas where root proximity is more of an issue and allows placement without the need to plasty the enamel of the adjacent tooth. Rationale for Treatment Approach Placement of MOD or dual proximal wall Class II restorations whether on the same tooth or on adjacent teeth have been wrought with the problems of open, loose or inadequate contacts irrespective of axial curvature, posing a risk for recurrent decay and the onset of periodontal problems with the tooth, not to mention the risk of mesial drift and the generation of occlusal disharmony. Often, the use of a circumferential matrix or the placement of back-to-back sectional matrix systems to establish proximal contacts have the disadvantage of having one acceptable contact and the other suboptimal. The approach described reconstructs a single wall at a time, aiming to convert the MOD Class II lesion into a Class I situation, in a step-by-step format whilst allowing for timely assessment (i.e. contact flossing) of the freshly built wall immediately before moving on the next step. The concept is similar to a pre-flight checklist. Every step is checked off before allowing one to complete the time-intensive occlusal anatomy sculpting. If a freshly built wall is unacceptable, one simply needs to prep it off without much investment of time or wasted effort. Treatment Marginal failure was diagnosed on tooth #19 relative to an existingMOD composite restoration (Fig. 1). The patient had been complaining about biting sensitivity with the tooth of 1 month duration. Primary concerns were both micromovement of debonded aspects of the old restoration, but also the possible presence of hairline fractures or cracks, which could only be elucidated via an exploratory restoration. The patient was anesthetized with 1 carpule of 2% Lignocaine with 1:100,000 epinephrine and a rubber dam placed (NicTone). Preparation ensued and the restoration was removed along with virtually all the liner underneath for assessment of the pulpal floor. No cracks or hairline fractures were identified, and the caries detector dye (Caries Detector, Kuraray) was utilized to ensure caries- removal endpoints (Fig. 2). The margins were bevelled (0.5-1.0mm) as the closer the cavosurface margin is to a cusp tip, the more one will be attempting to bond to the lateral aspects of enamel rods, whereas it is more effective to bond to the ends of enamel rods. Bevelling allows transverse exposure of the enamel rods and improved etching and bonding efficiency. Micro air abrasion was carried out isolating the adjacent tooth with a serrated metal strip using 27 micron aluminum oxide (Prep Start, Danville Engineering) under 2-3 bar of pressure. This was completed prior to placement of any sectional matrix system as typically roughening the actual matrix paired with the use of a 10-MDP containing self- etching adhesive (10-MDP bonds to non- precious metals) will see a more difficult matrix removal after buildup of the wall, indeed often with remnants of the Teflon color coating from the band left adhered to the restoration. Proximal Contact Control using the Garrison Compositight 3D Fusion Sectional Matrix System Clarence Tam clinical Procedure/Study by Clarence Tam, HBSc, DDS, AACD, FIADFE Figure 1 Figure 3 Figure 2 Figure 4