Success of 6-mm Implants with Single-Tooth Restorations: A 3-year Randomized Controlled Clinical Trial.

The aim of the study was to test whether implants of 6 mm in length perform equally well as 10-mm implants in terms of survival and marginal bone-level changes when supporting single crowns. Patients with a posterior single-tooth gap were randomly allocated to either the placement of a 6-mm (test) or 10-mm implant (control). The treatment protocol allowed for internal sinus lift but not for lateral bone augmentation. After a healing period of 10 wk, implants were loaded with screw-retained single crowns. Survival rates, number of pockets ≥5 mm, and bleeding-on-probing were assessed clinically. The change of marginal bone level and crown-to-implant ratios were analyzed by 2 examiners. Longitudinal intragroup analyses for marginal bone levels were performed applying the Wilcoxon signed rank test. Intergroup differences at baseline and at 3 y were compared using the Mann-Whitney U test. The effect of implant length and crown-to-implant ratio on changes of marginal bone level also was determined. Of 94 implants placed (47 test and 47 control), 78 implants (40 test and 38 control) were available for follow-up examination at 3 y of loading. One test implant was lost during the second year. Hence, implant survival was not significantly different between the 2 groups after 3 y (98% test; 100% control). We found no significant change in the crestal bone level from baseline to 3 y for test and control implants with -0.19 ± 0.62 mm and -0.33 ± 0.71 mm, respectively. The intergroup difference was not significant. Crown-to-implant ratios were not associated with a statistically significant difference in marginal bone loss. However, the number of sites with pockets ≥5 mm was significantly higher in the test group. Based on the 3-y assessment, the use of 6-mm implants can be considered a viable option when reconstructing posterior single tooth gaps (German Clinical Trials Registry: DRKS00006290).

Comparison between clinical and digital soft tissue measurements.

OBJECTIVE: The use of periodontal probes harbors the risk of measurement errors. The aim of this study was to investigate the accuracy of the digital determination of gingival recession and papilla height on virtual jaw models, given the hypothesis that they show lower intrarater and interrater variability than conventional linear measurements taken clinically or on cast models. MATERIALS AND METHODS: Gingival recessions and papilla heights were measured at 30 sites by five examiners using the following methods: (A) direct measurements using a periodontal probe intraorally or (B) on cast models using a caliper, (C) digital measurements on virtual models obtained by optical scans taken intraorally, or (D) made of cast models using the same software. Measurements were repeated after 1 week and intraclass, intrarater, and interrater correlations of the measurements using the four different methods were analyzed. RESULTS: The greatest disagreement between the 1st and 2nd measurement was identified for method A. Recessions were less reliably measured than papillae. The best agreement between methods was found in the digital ones (C and D). Regarding papilla height, increased values were obtained when method D was applied as compared with both clinical evaluations. For gingival recession, method A measured the highest values. CONCLUSION: In the present study, the use of digital technologies by intraoral scanning or scanning of cast models improved the reproducibility and lowered the variance of measurements within one individual and between different investigators. CLINICAL SIGNIFICANCE: Providing a more reliable and examiner-independent technique for measurements of the soft tissue architecture could improve data quality in periodontal research and in the analysis of different clinical treatment modalities.