[Effect of customized zirconia abutment on peri-implant tissue: a one-year prospective study]

Objective: To observe the changes of peri-implant tissue around the individualized abutment that was grinded from zirconia provisional crown in one year. Methods: In this research, a prosthodontic-driven virtual implant planning and immediate provisionalization were conducted in computer assisted design software. And computer-aided design/computer-aided manufacturing (CAD/CAM) techniques were used to fabricate the zirconia provisional crown and surgical guide template before surgery. The implant was accurately placed with the surgical guide, and the zirconia provisional crown was immediately delivered after surgery. Three months later, the implant osseointegration was completed, and zirconia provisional crown was prepared intraorally to generate customized zirconia abutment for final prosthesis. The study included 30 patients with single anterior tooth loss, including 18 males and 12 females, aged from 26 to 50 years old, and the mean age was (36.2±6.1) years old. The patients were from the Center of Oral Implantology, The First Affiliated Hospital of Zhejiang University Medical College from January 2017 to February 2018. After cementation of the final prosthesis, the cases were followed up at 6 and 12 months time intervals. Implant survival rate, probing depth, bleeding on probing, marginal bone level loss and papilla index score (PIS) were recorded in every appointment. Results: The survival rate of 30 implants was 100%, and the probing depths were less than 5 mm. The bone resorption at 6 and 12 months follow-up after the final delivery was 0 (0, 0) mm and 0 (-0.2, 0) mm, respectively, and the difference was not statistically significant (P>0.05). The PIS was 3.0 (2.0, 4.0), 3.0 (2.8, 4.0) and 3.0 (3.0, 4.0) on the final delivery, 6 and 12 months after final delivery, respectively. Conclusions: Marginal bone level and bone loss were stable with this new implant clinical protocol at the one-year follow-up.