Optical phenomenon of peri-implant soft tissue. Part I. Spectrophotometric assessment of natural tooth gingiva and peri-implant mucosa

Objectives: The purpose of this study was to investigate the difference in optical appearance of the soft tissues labial to dental implants and to analyze the effects of titanium implant neck colors transmitted through the marginal mucosa.

Materials and methods: Fourteen patients with 15 Straumann^® single implant replacements in the maxillary anterior region were recruited. Color measurements of the peri-implant mucosa of test sites and the gingivae of contralateral or adjacent natural teeth as controls were made at the facial aspect of the teeth using a spectrophotometer. The color data (CIELAB color coordinates; L^*, a^*, b^* and C^*) in five incremental areas of 1 × 2 mm from the gingival margin toward the apical direction were obtained.

Results: A significant difference existed (P<0.01) between the test site and the control site on the mean L^* and b^* values in all five incremental areas (area 1–5). In contrast, there was no significant difference in the mean a^* values. Discrepancies between color distributions of soft tissues were stronger in areas close to the gingival margin and decreased toward the apical direction. The mean color difference ΔE between the test site and the control site was 7.7 in area 1 and decreased toward area 5 with a value of 6.5. However, there was no statistical difference in each of the mean values of differences in optical data, ΔL^*, Δa^* and Δb^*, when five incremental areas of the control and the test sites were compared.

Conclusion: It was observed that the color of soft tissue around the titanium implant was significantly different compared with the gingiva of natural teeth. Significantly lower values of CIELAB color coordinates, L^* and b^* were found in the peri-implant soft tissue.