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.

OBJECTIVETo evaluate the effectiveness on the application of mechanical toothguide training box (TTB) to chromatics teaching of prosthodontics.

METHODS12 preclinical undergraduate students were chosen to participate in the VITA 3D-Master shade-matching system simulant toothguide training process using Linearguide Training Box program of TTB. Toothguide Trainer program considered as a test was performed on the trained undergraduate students group, the postgraduate students group as well as the clinical prosthodontists group with under 5-year clinical experience. The test scores, elapsed time and the coincidence of chromatics single factor matching were recorded each time, the shade-matching efficiency was calculated. The data was analyzed with SPSS 13.0 software.

RESULTSThe shade-matching efficiency of undergraduate students trained by TTB (64.03 +/- 18.82) was significantly higher than before (P < 0.05), higher than the postgraduate students group and the clinical prosthodontists group (P < 0.05). The coincidence of chromatics single factor matching of trained undergraduate students were 64.64% (lightness), 88.57% (chroma), 87.70% (hue).

CONCLUSIONTTB is a effective tool for shade-mathing practice in chromatics teaching of prosthodontics. The trained undergraduate students are less sensitive in lightness-matching.

Humans ; Prosthesis Coloring ; Prosthodontics ; Software