How do the dimensions of peri‐implant mucosa affect marginal bone loss in equicrestal and subcrestal position of implants? A 1‐year clinical trial

Abstract

[EN] Introduction: There is evidence that the apico-coronal implant position and themucosal phenotype can affect the extent of peri-implant bone loss. This clinical trialanalyzes the bone remodeling and marginal bone loss that occur around conical-connection implants placed equicrestally and subcrestally, assessing the effect of theperi-implant soft-tissue phenotype.Methods: Fifty-one patients received 56 implants of distinct diameters (3.5 mm Øn = 6; 4.3 mm Ø n = 41; 5 mm Ø n = 9) in the posterior part of the maxilla or mandi-ble. The implants were placed equicrestally, 1 mm subcrestally and >1 mm subcres-tally, depending on the initial supracrestal tissue height (STH). After 3 months ofnon-submerged healing, single metal-ceramic screw-retained implant-supportedcrowns were placed. Longitudinal measurements of STH, mucosal thickness and kera-tinized mucosa width (KMW) were made at the time of implant placement (T0),crown placement (T1), and after 3 (T2) and 6 months (T3) of prosthetic loading. Ateach of these points, a radiographic evaluation of bone remodeling and marginalbone loss was also performed.Results: STH was significantly greater for implants placed >1 mm subcrestally thanfor those placed 1 mm subcrestally. After 12 months of follow-up, a very significant(p < 0.001) loss of KMW was observed, in addition to a marginal bone loss of 0.08± 0.1, 0.15 ± 0.2, and 0.14 ± 0.2 mm in the groups placed equicrestally, 1 mm sub-crestally and >1 mm subcrestally, respectively. After the multiple linear regression,marginal bone loss was found to depend primarily on KMW (β = 0.43), while alsobeing affected by STH (β = 0.32) and implant diameter (β = 0.28).Conclusions: Marginal bone loss may be influenced by the position with respect tothe bone crest, as well as the KMW, STH, and implant diameter. However, morewell-controlled studies are needed to verify these above-mentioned findings with dif-ferent implant designs and connections