Surface Sealant Effect on the Color Stability of a Composite Resin Following Ultraviolet Light Artificial Aging.

OBJECTIVE: To examine how exposure to accelerated artificial aging (AAA) stimuli (ultraviolet [UV] light) affects the color stability of a composite resin following surface sealant (SS) application. METHODS AND MATERIALS: A total of 30 cylindrical composite resin (Esthet-X) discs were prepared using Teflon-coated rings. The treatment groups, defined by different SS (Seal-N-Sine, PermaSeal, OptiGuard, Biscover LV, and DuraFinish) use, were divided into five groups of six discs each. The discs were subjected to baseline color measurements followed by measurements after surface sealant application (specular included component [SCI] and specular excluded component [SCE]) using a spectrophotometer. Three measurements (SCI and SCE) were performed for a total of 18 readings (test surface) per specimen group. All specimens were then exposed to a UV light source for a total of 382 hours. Color readings of the specimens were again recorded for each group. Quantitative color measurements were executed using Commission Internationale de l'Eclairage L*a*b* calculations. RESULTS: Baseline color measurements of the composite resin discs, following the AAA exposure protocol, revealed no significant differences. A comparison of the composite resin discs before and after SS application (without UV light exposure) showed statistically significant differences using both SCI and SCE measurement criteria. Although significant differences were encountered between the ΔL*, Δa*, Δb*, and ΔE parameters, all specimens (groups) were within the clinically acceptable range (1.0<ΔE≤ 3.3). Again, statistically significant differences were noted (ΔL*, Δa*, Δb*, and ΔE parameters) for all specimen groups receiving SS application, utilizing both SCI and SCE measurements, following exposure to UV light. All groups were within the clinically acceptable range (1.0<ΔE≤ 3.3), except the Durafinish group. The Durafinish SS group experienced significantly greater (p<0.001) overall color change (SCI and SCE) following UV light exposure. An intergroup comparison following UV exposure revealed that the Permaseal, OptiGuard, and Seal-n-Shine SS groups displayed the least amount of color change statistically but not necessarily always perceptibly significant, while the Durafinish group exhibited the greatest color change statistically and perceptibly. CONCLUSIONS: The color stability of a composite resin, including the addition of most SSs, was not affected perceptibly by UV light exposure.

Biomechanical criteria for evaluating prefabricated post-and-core systems: a guide for the restorative dentist.

Selecting the optimum prefabricated post-and-core system can be a complex and imprecise exercise for the restorative dentist. First, no single prefabricated post-and-core system fits all situations. Second, the vast number of post-and-core components currently on the market complicates the selection process. Finally, useful biomechanical criteria for evaluating prefabricated post-and-core components are difficult to quantify. The prefabricated post-and-core system consists of three components: the post, a core material, and a luting cement. Each combination of component types is a potential system alternative. This article presents useful biomechanical criteria, based on current restorative guidelines, for evaluating the basic components of any prefabricated post-and-core system.

Color vision and dentistry.

Color vision is a critical component of restorative and esthetic dentistry, but dentists, as a group, do not have their color vision tested at any time during their careers. A study was undertaken to ascertain the color-vision status of practicing dental personnel at the University of Tennessee, College of Dentistry. One hundred fifty individuals, 75 men and 75 women, were screened. The results corroborated the existing medical data for the general population. It was found that 9.3% of the men and none of the women exhibited color-vision defect. Since most dentists are male, this study demonstrates an area of potential weakness for some practitioners. Once a color-vision problem is found, it is simple to remedy by employing a team approach to shade matching or mechanical means of matching shades (by the practitioner). No ethnic or racial distinctions were detected, although these have been reported in other studies.