Retrospective analysis of augmentation procedures with Umbrella screws a novel tenting technique: a consecutive case series in 279 patients.

OBJECTIVES: The consecutive case series accesses the results and experiences of ridge augmentation using an umbrella-screw (US) tenting technique.

MATERIALS AND METHODS: 279 patients have been treated between 05/26/2015 and 08/16/2021 including horizontal and vertical ridge defects. Gender, age, smoking behavior, jaw, graft material, soft tissue thickness, extent of horizontal/vertical augmentation, resorption rate and occurrence of early/late exposure were evaluated. Bone gain was determined by resorption at the screw head. Only cases without premature screw removal were evaluated metrically (n=201). All other augmentations were evaluated according to whether implantation was possible with or without further augmentation (n=27). A target performance index (TPI) was calculated, which should enable evidence-based comparability of different augmentation methods in future.

RESULTS: 54 wound dehiscence (39 early, 15 late exposures) occurred, which corresponds to 24.08 % of the augmented sites. 42 US were removed prematurely. In all cases an implantation was possible at the desired position afterwards. Cases with a vertical augmentation component showed a higher prevalence of exposure (early (p=0.000), late (p=0.024)). The extend of the vertical augmentation showed only to be relevant for early exposure (p=0.048). Mean bone gain of 4.23 mm ± 1.69 horizontally and 4.11 mm ± 1.99 vertically could be achieved. Regression analysis showed that there was no limit in horizontal/vertical direction. Mean percental TPI was 75.90 ± 20.54 for vertical and 82.25 ± 16.67 for horizontal portions.

CONCLUSION: The umbrella-technique is an effective augmentation method, which can be applied to any defect morphology.