Clinical effect of Nobel Biocare angulated screw channel crown compared with cement crown in the aesthetic area: A retrospective cohort study with a mean 32 months follow-up (range 12 to 70 months).

OBJECTIVE: The objective of this study is to compare the clinical efficacy of angulated screw channel abutment applied in the anterior area with regular cemented crowns.

MATERIALS AND METHODS: Forty-eight patients were included and divided into two groups: the angulated screw channel group (ASC) and regular cemented group (RC) in this retrospective cohort study. The evaluation criteria included implant/restoration survival rate, keratinized mucosa width (KMW), bleeding on probing rate (BOP%), probing depth (PD), pink aesthetic score (PES), mechanical/biological complications, emergence angle (EA), the site of implant axis penetrate (SA), marginal bone loss (MBL), and buccal bone thickness (BBT) at 0 mm, 1 mm, 3 mm, 5 mm below the implant shoulder were evaluated in immediate postoperative (T0) and follow-up period (T1).

RESULTS: This retrospective cohort study included a total of 48 patients, with a mean 32 months follow-up period range from 12 months to 70 months. The study did not find any cases of implant failure or restoration failure. EA was significantly wider in the RC group than ASC group (RC: 33.53° ± 8.36° vs ASC: 27.43° ± 8.08°, p = 0.016*). While the BOP% was statistically significant higher in the RC group than ASC group (RC: 28.35% ± 22.92% vs ASC: 13.18% ± 20.00%, p = 0.027*). No significant differences were observed in the other measurements of comparison.

CONCLUSION: Within the limitations of the study, angulated screw channel (Nobel Biocare) crowns might allow the implant axis aim at incisal edge to reduce the emergence angle in the anterior area and benefit the soft-tissue during the 12-70 months follow-up period.