The effect of zirconia and titanium implant abutments on light reflection of the supporting soft tissues.

OBJECTIVES To determine the difference in light reflection of oral mucosa covering titanium (Ti) or zirconia (ZrO(2)) abutments as it relates to the thickness of the covering mucosa. MATERIAL AND METHODS Fifteen anterior implants (Astra Osseo speed(®)) in 11 patients were fitted with a Ti or a ZrO(2) abutment (cross-over, within-subject comparison). Hyper-spectral images were taken with a camera fitted on a surgical microscope. High-resolution images with 70 nm interval between 440 and 720 nm were obtained within 30 s (1392 × 1024 pixels). Black- and white-point reference was used for spatial and spectral normalization as well as correction for motion during exposure. Reflection spectra were extracted from the image on a line mid-buccal of the implant, starting 1 mm above the soft tissue continuing up to 3 mm apically. RESULTS Median soft tissue height is 2.3 mm (min: 1.2 mm and max: 3.1 mm). The buccal mucosa rapidly increases in the thickness, when moving apically. At 2.2 mm, thickness is 3 mm. No perceivable difference between the Ti and ZrO(2) abutment can be observed when the thickness of the mucosa is 2±0.1 mm (95% confidence interval) or more. CONCLUSION It is expected that the difference in light reflection of soft tissue covering Ti or ZrO(2) abutments is no longer noticeable for the human eye when the mucosa thickness exceeds 2 mm. Haemoglobin peaks in the reflection spectrum can be observed and make hyper-spectral imaging a practical and useful tool for measuring soft tissue health.