Reliability of the Implant Stability Measurement Performed at the Abutment Level. A Retrospective Clinical Trial and an In Vitro Research.

Purpose - The use of the one abutment one time concept involves the indirect measurement of the implant stability without removing the previously placed abutment. This study aims to verify whether measuring the implant stability quotient at the abutment level is identical to the value obtained at the implant level. Material And Methods - A retrospective clinical study and an in vitro study were performed. For each study, the implant stability quotient measured at the implant level defined the control groups. The values obtained after the abutment seating composed the test groups, which were divided into three test sub-groups, corresponding to three different multi-unit abutments: straight (MUAS) and 17° angled (MUA17), both with 2.5 mm collar, and 30° angled (MUA30) with 3.5 mm collar. Data was compared by the Wilcoxon signed rank test and Kruskal-Wallis test. Results - Clinical results: the control group (59 implants; 79.14 [SD=3.39]) showed significantly higher measurements than the test group (73.22 [SD=8.54]); the sub-groups ClinicalMUA17 (16 abutments; 66.38 [SD=1.20]) and ClinicalMUA30 (16 abutments; 69.19 [SD=0.96]) measurements were lower than the control group. No differences were found for the ClinicalMUAS (27 abutments; 79.67 [SD=1.48]) sub-group when compared with the control group (correlation of 0.68). In vitro results: the control group measurements (36 implants; 68,02 [SD=1.81]) were significantly higher than the test group (62.57 [SD=2.87]). The control group measurements were also higher than each test sub-group (12 abutments each): MUAS (65.44 [SD=0.73]); MUA17 (60 [SD=0.43]); MUA30 (62.29 [SD = 0.35]). Conclusions: Based on the results of this study, determining the implant stability quotient at abutment level results in lower values than measurements at implant level, and may not accurately reflect the actual implant stability. Future research will need to explore whether, and under what circumstances a correlation exists between the implant stability quotient measured at the implant level and at the abutment level.