Comparison on accuracy of porcelain color reproducibility using two colorimeters / 대한치과보철학회지

STATEMENT OF PROBLEM: Although the use of colorimeter to improve the accuracy of tooth color measurement has increased, it is real situation that there is almost no comparative study about the accuracy among various colorimeters. PURPOSE: The purpose of this study is to compare the accuracy of porcelain color reproducibility using ShadeEye-Ncc dental chroma meter (Shofu Inc., Kyoto, Japan) and Shadepilot(TM) system (Degudent Inc., Hanau, Germany). MATERIAL AND METHODS: Color of 2M2 and 3M2 shade tap of Vitapan 3D Master shade guide were measured using the above two colorimeters. Porcelain specimens were fabricated through this data. The porcelain systems used were Vintage Halo Porcelain system with ShadeEye-Ncc dental chroma meter, and VitaOmega900 Porcelain system with Shadepilot(TM) system. Colors of shade tap models and porcelain specimen were measured with spectrophotometer, and calculated delta E based on the results. RESULTS: The following results were obtained. 1. Shadepilot(TM) system showed more suitable porcelain color reproducibility compared to ShadeEye-Ncc dental chroma meter (P < .05). 2. The result showed the difference of porcelain color reproducibility according to shade of Shade tap which is model. More suitable porcelain color reproducibility was shown at 3M2 shade tap than at 2M2 shade tap (P < .05). 3. The average of DeltaE* of porcelain specimens which was made by the two colorimeters was 4.44-6.14, so the difference of shade was shown through the naked eye. CONCLUSION: Shadepilottrade mark system showed more suitable porcelain color reproducibility. When using ShadeEye-Ncc dental chromameter, it will be necessary to improve accuracy through coloring various parts of the whole tooth.

Clinical study of shade improvement and safety of polymer-based pen type BlancTic Forte whitening agent containing 8.3% Carbamide peroxide / 대한치과보존학회지

This clinical study evaluated the whitening effect and safety of polymer based-pen type BlancTis Forte (NIBEC) containing 8.3% carbamide peroxide. Twenty volunteers used the BlancTis Forte whitening agent for 2 hours twice a day for 4 weeks. As a control, Whitening Effect Pen (LG) containing 3% hydrogen peroxide was used by 20 volunteers using the same protocol. The change in shade (DeltaE*, color difference) was measured using Shadepilot(TM) (DeguDent) before, during, and after bleaching (2 weeks, 4 weeks, and post-bleaching 4 weeks). A clinical examination for any side effects (tooth hypersensitivity or soft tissue complications) was also performed at each check-up. The following results were obtained. 1. Both the experimental and control groups displayed a noticeable change in shade (DeltaE) of over 2. No significant differences were found between the two groups (p > 0.05), implying that the two agents have a similar whitening effect. 2. The whitening effect was mainly due to changes in a and b values rather than in L value (brightness). The experimental group showed a significantly higher change in b value, thus yellow shade, than the control (p < 0.05). 3. None of the participants complained of tooth hypersensitivity or soft tissue complications, confirming the safety of both whitening agents.

Shade comparative analysis of natural tooth measured by visual and spectrophotometric methods / 대한치과보철학회지

STATEMENT OF PROBLEM: A clinically successful color match is one of the important factor to get an esthetic dental restoration. Dental shade guides are commonly used to evaluate tooth color in restorative procedure. But numerous reports have indicated that common shade guides do not provide sufficient spectral coverage of the natural tooth colors. To address issues associated with the shade guide, distinct avenues have been pursued objective spectrophotometric / colorimetric assessment. PURPOSE: This study compared the accuracy of tooth color selection of spectrophotometer with that of human visual determination. Three main factors were investigated, namely, the effect of light, the individual variation and the experience of the observer. MATERIAL AND METHODS: At the first experiment, on ten patients, one operator independently selected the best matching shade to the unrestored maxillary central incisor, using a Vita Classical Shade Guide in the morning, at noon and in the afternoon. The same teeth were measured by means of a reflectance spectrophotometer. At the second experiment, on ten patients, ten operators (5 experts, 5 novices) selected and measured by the same method above at noon. At the third experiment, the results of the second experiment were divided into two groups, expert and novice, and analyzed. RESULTS: 1. There was significant difference between visual and spectrophotometric assessment (mean delta E values) in experiment 1, 2, 3 (p < .05). 2. There was no significant difference between experts and novices group, when comparing with each visual and spectrophotometric assessment (mean delta E values). CONCLUSION: Spectrophotometer could be used to analyze the shade of natural tooth objectively. Thereby, this method offers the potential tominimize considerably the need for corrections or even remakesafter intraoral try-in of restoration. Furthermore, to achieve its advantage, both the shade-matching environment and communication between dentist and technician should be optimized with use of visual and instrumental shade-matching systems.