A 7.5‐year randomized controlled clinical study comparing cemented and screw‐retained one‐piece zirconia‐based implant‐supported single crowns

Abstract

AbstractObjectivesTo compare marginal bone levels, biological, and technical outcomes of screw‐retained versus cemented all‐ceramic implant‐supported zirconia‐based single crowns after an observation period of 7.5 years.MethodsForty‐four single implants in the esthetic zone in 44 patients (22 females, 22 males) were randomly assigned to two types of restorations: SR (screw‐retained); veneered one‐piece zirconia abutment and CR (cement‐retained); veneered lithium disilicate crown intraorally cemented on a one‐piece zirconia abutment. Patients were recalled annually up to 7.5 years and survival rates, biological, and technical parameters assessed.ResultsA total of 31 patients attended the 7.5‐year follow‐up visit (17 SR group, 14 CR group). The survival rate on the restorative level was 77.5% (74.0% CR, 81.0% SR, p = .6399). Median marginal bone loss (MBL) values yielded −0.073 mm (−0.305; 0.238) in the CR and −0.215 mm (−0.500; 0.555) in the SR group (intergroup p = .6194). Mean bleeding on probing (BoP) values were significantly in favor of group SR with 20 ± 17% compared to 40 ± 22% in group CR (p = .011). The overall biological complication rate amounted to 27.5% (42.1% CR, 14.3% SR, p = .0775), whereas the technical complication rate was 32.5% (42.1% CR, 23.8% SR, p = .314). In total, CR restorations showed significantly more complications (84.2% for CR, 38.1% for SR, p = .0041).ConclusionOne‐piece zirconia‐based single crowns on two‐piece dental implants exhibited a high rate of technical and biological complications at 7.5 years of follow‐up. Cemented restorations revealed significant higher rates of bleeding on probing and total complications compared to screw‐retained restorations.