Health of peri-implant soft tissues adjacent to glazed or polished monolithic zirconia: a randomized clinical trial

Material surfaces can influence the biological response of soft tissues, particularly during the early stages of healing and maturation. This study assessed whether the type of surface finish (glazed or polished) of monolithic zirconia single crowns impacts the health of peri-implant soft tissues during the first 6 months of clinical function. Infrared thermography was employed to assess soft tissue conditions.

This was a prospective, randomized, intra-participant clinical trial. Twenty single crowns, supported by posterior implants, were fabricated in monolithic zirconia using computer-aided design/computer-aided manufacturing. For each crown, the mesial and distal surfaces were randomly allocated to receive either a glazed or a polished surface finish. Data were collected at 7 (T1) and 180 days (T2) following crown placement, using clinical examinations (assessing pain/discomfort, biofilm formation, bleeding, inflammation, and suppuration) and infrared thermography (to record thermogram values in Celsius). The data were analyzed using both descriptive and inferential statistics.

No significant clinical differences in peri-implant soft tissue health were identified between the glazed and polished surface treatments at T1, T2, or across the evaluation period. Infrared thermography revealed a significant decrease in temperature from T1 to T2 for some polished and/or glazed subgroups when comparing the peri-implant mucosal phenotype, dental arch, and tooth regions. However, no significant differences were observed between the polished and glazed groups.

Both glazing and polishing are suitable surface treatments for monolithic zirconia and do not adversely affect peri-implant soft tissue health within 6 months after crown installation. Infrared thermography has the potential to be a complementary tool for the objective evaluation of soft tissue healing.