PurposeAims of the study were: (a) to register crestal bone loss around 1.5 mm subcrestally placed implants and epicrestally placed implants with soft tissue tenting technique, (b) to record bone remodeling in subcrestal group, and (c) to determine the increase of vertical soft tissues after tenting.Materials and methodsThirty‐two patients with vertically thin tissues of 2 mm or less received 40 submerged bone level platform‐switched implants, divided into two groups—(a) 1.5 mm subcrestally placed implants and (b) epicrestally placed implants with soft tissue tenting over 2 mm healing abutments. At the second stage surgery, implants received 4 mm healing abutments, soft tissue thickness was measured in epicrestal group, and later implants were restored with zirconia‐based screw‐retained single restorations. Radiological images were taken at the second stage surgery, restoration delivery and after 2 years of follow‐up. Bone loss was calculated as a distance between implant neck and first radiographically visible bone‐to‐implant contact. Bone remodeling was calculated as a distance between the bone crest and implant neck. Mann‐Whitney U test was used for statistical analysis, significance set to 0.05.ResultsAfter 2 years of follow‐up, Group 1 (subcrestal) had 0.18 ± 0.32 mm of bone loss, Group 2 (epicrestal with 2 mm healing abutment) had 0.51 ± 0.4 mm of bone loss, with statistically significant difference (P = .001). Bone remodeling in Group 1 (subcrestal) was 1.17 ± 0.51 mm. Vertical tissue thickness in epicrestal group before the intervention was 1.85 ± 0.26 and 3.65 ± 0.41 mm after the use of 2 mm healing abutment, with a statistical difference (P = .005).ConclusionSubcrestal implant placement can significantly reduce crestal bone loss, compared to vertical soft tissue thickening by tenting of epicrestally placed implants, although soft tissue tenting can significantly increase soft tissue thickness.

Background The relation between implant abutment disconnection (AD) and increased crestal bone loss is still debated. Purpose To compare bone changes below implant‐abutment junction of subcrestally placed implants between: (1) implant level restorations, that underwent four ADs and (2) implants with immediate tissue level abutment with no AD, 1 month (T2) and 1‐year (T3) after final restoration delivery. Materials and methods Sixty‐four patients received 64 bone level implants with platform‐switching and conical connection in edentulous sites of posterior mandible and maxilla. All implants were placed 1.5 mm subcrestally and distributed among: (1) control group, that received a regular healing abutment and (2) test group with immediate tissue level (ITL) abutment, which was torqued to implants during surgery, transforming bone level implant to tissue level type. After 2–3 months of healing and a 1‐month temporization, final zirconia‐based screw‐retained crowns were delivered to both groups. Crestal bone levels were calculated after final crown delivery (T2); after 1‐year follow‐up (T3) and compared using Mann–Whitney U test (p ≤ .05). Results Early bone loss of the test and control groups was 0.14 ± 0.27 mm and 0.64 ± 0.64 mm, respectively; the 0.5 mm difference was statistically significant (p = .0001). Late bone loss was 0.06 ± 0.16 mm and 0.21 ± 0.56 mm for the test and control group, respectively; the 0.15 mm difference between the groups was no more statistically significant (p = .22). Both groups displayed bone gain, 0.08 and 0.43 mm, respectively, and the overall crestal bone loss was reduced. Conclusions Immediate tissue level abutments can significantly reduce early bone loss when measured 1 month after final prosthesis delivery, however, after 1‐year follow‐up, difference between the groups was no more statistically significant.

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