ABSTRACT
OBJECTIVE@#To select the most effective method among different masking treatments, such as different thickness and transparence, tissue surface's opaque coating, and opaque resin cement to restore discolored teeth esthetically by porcelain veneer.@*METHODS@#Four extracted intact maxillary central incisors were prepared for porcelain veneer restoration and each three heat pressed porcelain veneers from three thicknesses (0.8 mm, 1.0 mm, 1.2 mm) and two transparency(high transparence, HT and low transparence, LT))in Vita shade A2 were fabricated for each tooth, in total of 72 pieces. The surfaces of three prepared teeth were then painted to mimic situations of severe dental fluorosis, severe tetracycline teeth, and necrotic teeth. Each of the veneers was temporarily cemented to the corresponding tooth surface using try-in cements with three different colors (transparent, opaque, and yellow), then used the shade guide (3D master) and electronic colorimeter (easy shade) to record the shade of each porcelain veneer through hue, lightness, and chroma reading. After that, high-transparence porcelain veneers in thickness of 0.8 mm was fused with a layer of opaque porcelain in tissue surface, and were shade matched again after cementation. Statistic treatments were performed to analyze the difference in each masking method.@*RESULTS@#For each 0.2 mm increase in the veneer thickness of porcelain, the average lightness was reduced by 1 unit, while the chroma was not changed which was independent of the type of the resin cements. When the thickness of the porcelain veneer was decreased to 0.8 mm, the opacity effect was not remarkable even if a low-transparence porcelain veneer was used. Transparent and yellow resin cements had poor opaque performance, while opaque resin cement could reduce the lightness by 2 units and the chroma was also reduced. The opaque layer of the tissue surface could be applied uniformly, and the lightness and chroma could be reduced to Vita 2M1 to 2M1.5 levels regardless of the color of resin cements, which suggested a stable opacity effect for different discolored teeth in this study.@*CONCLUSION@#For porcelain veneer restoration of discolored teeth, thickened veneers are the most effective means to display a natural transmittance and color. Tissue surface's opacity coatings and opaque resin cements can also be used to reduce grayscale and increase lightness.
Subject(s)
Humans , Color , Materials Testing , Prosthesis Coloring , Resin Cements , Tooth Discoloration/therapyABSTRACT
Aim: The purpose of this study was to determine the closest matching shade for primary maxillary anterior teeth from the most widely used Vitapan classical shade guide available for permanent teeth. Materials and Methods: A total of 313 children aged between 3 and 5 years were evaluated. Vitapan classical shade guide was used to determine the shade of six primary maxillary anterior teeth. Scores obtained were noted down in a scoring sheet and values were tabulated. Data collected were tabulated and statistically analyzed using Pearson Chi‑square test. Results: A1 was found to be the closest matching shade for primary maxillary anterior teeth. D3 was found to be the least prevalent shade for primary maxillary anterior teeth. There was no statistical significant difference in the shades among teeth of same quadrant (p > 0.05) and also between teeth of right and left quadrants (p > 0.05), respectively. Conclusion: A1 shade of Vitapan classical shade guide is the most prevalent shade for primary maxillary anterior teeth and can be satisfactorily reproduced to all primary maxillary anterior teeth in general.
ABSTRACT
Objective; To evaluate the effects of gingival shade guide in visual shade-matching in vitro models. Methods; 42 tabs of Shofu NCC shade guide were adopted for color measuring. Each tab was fixed in the middle of Gingiva-Indicator, Guray(1,2,3,4) respectively and located in a black box. The measurements were made using the Shadepilot instrument. The color parameters ( CIE1976L * a * b * ) of cervical, body, incisal area of each tab were recorded. The color difference A E value in the same position of each tab was calculated between non-gingival shade guide group and Gumyl ,2,3,4 groups with Shadepilot software. Results; The AE value in the same position of 42 tabs between non-gingival shade guide group and 4 gingival shade guide groups were; cervical (2.93±0.79)NBS,body(0.51±0.27)NBS and incisal(0.61 ±0.29)NBS. In the cervical, body and incisal area, there was no statistically difference among Gumyl ,2,3,4 groups on affecting shade of tabs(P >0. 05). Conclusion; The gingival color has an effect on the cervical shade of tabs, and it can be recognized by human eyes, while gingival color has little effect on the shade of body and incisal area.
ABSTRACT
STATEMENT OF PROBLEM: Shade selection has traditionally been accomplished by visual examination, which is particularly relevant to the shade selection of anterior teeth, but the subjective nature of visual analysis can lead to errors in shade matching. Recently shade selection systems have been developed to provide a more objective and scientific approach to understanding and clarifying shade selection. PURPOSE: The purpose of this study was analysis of various shade analyzing equipment with the goal of providing a more objective shade selection. Materials and method: Visual shade matching system selection(Vita Lumin Vacuum shade guide, Vitapan 3D Master shade guide) and mechanical shade matching method(ShadeEye (R) -EX Chroma Meter, ShadeScan(TM) System) used for this study. The shade guide tap specimens for 10 extracted maxillary anterior teeth were produced by selecting shades using each shade matching system. The accuracy of the selection of shades for the teeth and fabricated specimens were evaluated by analyzing the calculated shade difference(delta E*), using a spectrophotometer and calculating the output of value L*, a*, b*. RESULTS AND CONCLUSION: The results show that the average delta E* value (difference of shade) of the shade tap specimens to the actual specimen decreased in the following order: Vita Lumin Vacuum Shade Guide(VL), ShadeEye(R)-EX Chroma Meter(SE), Vitapan 3D Master Shade guide(V3), and ShadeScan(TM) System(SS); and that there are significant statistical differences between the VL and SS (p<0.05). In the analysis of the delta E* (difference of shade) value, 40% of the VL group was found to be less than 3.3 (limit value of shade tap specimens clinically acceptable), 60% in the V3 group, 50% in the SE group, and 80% in the SS group.