Effect of abutment height on interproximal implant bone level in the early healing: A randomized clinical trial

Objective: The aim of this randomized clinical trial was to compare the effect on the interproximal implant bone loss (IBL) of two different heights (1 and 3mm) of definitive abutments placed at bone level implants with a platform switched design. Material and methods: Twenty-two patients received forty-four implants (6.5-10mm length and 3.5-4mm diameter) to replace at least two adjacent missing teeth, one bridge set to each patienttwo implants per bridge. Patients were randomly allocated, and two different abutment heights, 1 and 3mm using only one abutment height per bridge, were used. Clinical and radiological measurements were performed at 3 and 6months after surgery. Interproximal bone level changes were compared between treatment groups. The association between IBL and categorical variables (history of periodontitis, smoking, implant location, implant diameter, implant length, insertion torque, width of keratinized mucosa, bone density, gingival biotype and antagonist) was also performed. Results: At 3months, implants with a 1-mm abutment had significantly greater IBL (0.830.19mm) compared to implants with a 3-mm abutment (0.14 +/- 0.08mm). At 6months, a greater IBL was observed at implants with 1-mm abutments compared to implants with 3-mm abutments (0.91 +/- 0.19 vs. 0.11 +/- 0.09mm). The analysis of the relation between patient characteristics and clinical variables with IBL revealed no significant differences at any moment except for smoking. Conclusions: Abutment height is an important factor to maintain interproximal implant bone level in early healing. Short abutments led to a greater interproximal bone loss in comparison with long abutments after 6months. Other variables except smoking showed no relation with interproximal bone loss in early healing.