Temporary conventional restorations vs contemporary for the CAD / CAM system: analysis of optical characteristics before and after different cycles of thermal fatigue in acidic/colorant solutions

Abstract

The optical characteristics of the provisional restorations are as important as their mechanical properties, especially during their time of functionality in the oral cavity. Currently, the pre-fabricated polymer blocks for CAD/CAM system have emerged as an excellent alternative for confection of temporary aesthetic restorations. However, it is important to know its optical characteristics, due to the degradation caused by the prolonged use of the restoration, in comparison with other materials used to make temporary restorations. Thus, the present study will evaluate the color stability (”E), translucency (TP) and degree of contrast (CR) of different types of resins used to make temporary restorations before and after different cycles of thermal fatigue in acidic/colorant solutions. A total of 160 specimens with 10 × 10 × 3 (± 0.005) mm were divided into 16 groups (n = 10) according to the material and acidic/colorant solutions. Four different dental resins will be evaluated: (RAT - thermo-polymerizable acrylic resin (Classical), RAA - self-cured acrylic resin (Alike), RB - nanoparticulate bisacrylic resin (Protem4) and RCAD - prefabricated polymer block (PMMA) for the CAD system (Telio CAD); submitted to aging by means of different tests: (Control (C): in distilled water at 98,6°F for the imersion period(45 and 90 hours); (TF1): 2,500 cycles thermal fatigue, from 41 to 131°F for 30 seconds; (TF2): 5,000 cycles thermal fatigue and (TF3) 10,000 cycles of thermal fatigue. During the termal fatigue, the specimens will be immersed respectively in different acidic/colorant solutions (C - coffee, V - red wine, R - cola) and the immersions will be realized intercalating with immersion in destilated water in a thermocycler, since the acidic ingestion ir not continuous, but intercalated with exposion in non-colorant solutions. The readings of the optical characteristics of the specimens will be performed by visible ultraviolet reflection spectrophotometry, model UV-2450 in two backgrounds (black and white), before and after each period of thermal cycles. The data will be submitted to the analysis of variance (ANOVA), a single factor for ”E and ANOVA with repeated measures of two factors for TP and CR. The Tukey test will be applied for all analysis, with a significance of 5%. (AU)