Zhereb T.V, Amangeldy A.A , Bakhtybaeva A.K..

Karaganda State medical university

FINISHING AND POLISHING RESTORATIONS: TECHNICAL FEATURES OF PERFORMANCE DEPENDING ON THE TYPE OF RESTORATIVE MATERIAL

Introduction

Compared to earlier generations of restorative materials, today’s composite resins provide improved strength, resistance to wear, and esthetics, and have revolutionized the concept of minimally invasive dental treatment . To achieve the benefits that composite restorations can provide, it is incumbent on dentists to understand the importance of proper finishing and polishing techniques and how to incorporate them appropriately into everyday practice. Aim To investigate finishing and polishing as material sensitive processing of composite restorations. Materials and methods Analytical review of the literature devoted to the problems of finishing and polishing restorations.

Results Properly finishing and polishing composite restorations offers many benefits that ultimately lead to a predictable, long-lasting, and highly esthetic result . However, finishing and polishing procedures are material sensitive. Just as classes of composite materials demonstrate different esthetic qualities and tensile strengths, polishability and maintainability in the longterm can vary, based on inherent particles and filler size. Research has demonstrate that composite filler size and the systems used to finish and polish restorations influence surface roughness and staining . In general, composites should mirror natural tooth structure in color and translucency, withstand function in high stress-bearing areas over time, have seamless or undetectable margins, and allow for a polish that can be maintained over the life of the restoration. Now available in a variety of formulations for different indications, today’s composites provide many added benefits, specifically in finishing and polishing, compared to the conventional materials of the past. For example, hybrid or microhybrid composites are heavy-loaded materials that demonstrate high strength and opacity similar to that of natural dentin and enamel. Additionally, microhybrids are less likely to chip or fracture because they demonstrate excellent strength and the ability to withstand functional stresses. Microhybrids blend with the natural dentition to create an esthetic restoration, allowing the practitioner to mimic dentin and enamel morphology. An issue with this class of composite materials, however, is their inability to maintain a polish; they tend to lose surface gloss over time and are less stainresistant than other generations of composite. Filler particles in microhybrids have been shown to “pluck out” during the polishing process and normal lifespan in the oral cavity, and, as a result, restorations can lose gloss or luster over time. Studies have demonstrated that although it might not be as easy to maintain a polish as it is for other classes of composites, hybrids tend to be resistant to surface microfractures during finishing, for reasons that are believed to be directly related to the presence of inorganic fillers and their ability to absorb energy. In comparison, microfill composites demonstrate high polishability that lasts for the long term. Many authors have gone so far as to deem the smoothness achieved with microfill composite materials as “permanent.” A direct effect of the inclusion of colloidal silicaparticles in the polymer matrix, small fillers and a resin-rich surface promote an excellent and maintainable polish. Additionally, microfills demonstrate a higher resistance to wear and abrasion and a translucency that is similar to that of natural enamel. This class of composites lacks the strength required in functional areas and often translucency is too great. Despite its high polishability, this class of composites demonstrates a higher susceptibility to stain than newer generations of composite. The newest class of composite materials, nanofills have the potential to maintain greater strength, long-term polishability, and stain resistance. Studies have illustrated that nanofilled materials exhibit the lowest incidences of roughness and wear after finishing and polishing and on recall when compared to other classes of dental composites. This class of composites demonstrates the smoothest polished surface and lowest surface roughness, regardless of the polishing system used. Additionally, with a greater resistance to wear, nanofilled materials offer the most ideal mechanical and optical properties. Further, nanofilled composites display opacity similar to that of natural enamel and dentin, with translucency similar to that of enamel. Demonstrating high strength, nanofilled composites also are less likely to chip in high-stress areas. The only true disadvantage to nanofilled composites is the lack of in vivo long-term studies, because the material science is relatively new. Thus, the main composite placement considerations to enhance the finishing and polishing processes are :

1. Reduction guides When creating direct resin restorations, preparation is of the utmost importance. Overly aggressive preparation for the sake of esthetics often leads to unnecessary loss of tooth structure. Although necessary in some extreme cases, this loss of tooth structure typically can be avoided with the use of a reduction guide. Further, reduction guides have proven useful in controlling midlines in cases requiring diastema closure and when complex bonding is required .

2. Proper handling Whether the composite material is placed on the facial surface, interproximally, or around the gingival tissues, the manner in which the composite is handled can greatly affect the appearance of a restoration. To handle composites properly, ensure that no air voids are present in the increments being placed. Further, placing smaller increments predictably, instead of placing bulk quantities of material at once, helps to ensure proper control of the material. Sensitivity can be eliminated by completely curing each composite increment and allowing the restorations to reach their full photocure potential.

3. Undetectable margins To create undetectable margins in the esthetic zone that are not only esthetic but also resistant to leakage, a starburst bevel should be used, followed by etching beyond the bevel. The outer layer of composite must be rolled while wearing clean gloves to improve sculptability and prevent voids. The material should then be placed, supercured, and allowed to “relax” for at least five minutes to allow the material to settle. Next, the margin should be addressed and finished back between where the etch-and-bevel ends. To ensure the best results, rubber wheels and polishers should not be used on the margins,because the rubber tends to become easily embedded in this area. Conclusions. By adhering to the requirements of the specific composite and restoration, the ideal contour, finishing, polish, and luster were achieved in the restorative result. Incorporating an appropriate polishing sequence and system based on the materials used can enable dentists to provide patients with composite restorations that demonstrate predictable longterm esthetics, plaque and stain resistance, and function.