Clinical phenomena of bone responses depending on implant-abutment connection structures

Abstract

-ABSTRACT-

Clinical phenomena of bone responses depending on implant-abutment connection structures

Jin-Cheol Kim, D.D.S.

Department of Prosthodontics, Graduate School, Seoul National University

(Directed by Professor In-Sung Yeo, D.D.S., M.S.D., Ph.D.)

1. Purpose

This study aimed to evaluate the effect of two different implant–abutment connection structures with identical implant design on peri-implant bone level.

2. Materials and Methods

This clinical study was a randomized controlled trial following the CONSORT 2010 checklists. Implants with internal friction connection were compared to implants with external hex connection. Eleven external hex and eleven internal friction implants were analyzed in this study. These implants had the same design except the connection structure. One implant for each patient was installed, replacing the second molar in the maxilla or mandible. Cement-retained crowns were delivered at four months after implant insertion. Standardized periapical radiographs were taken at prosthesis delivery (baseline), and one year after delivery. On the radiographs, distance from implant shoulder to first bone-to-implant contact (DIB) and peri-implant area (PA) were measured. These measurements were compared between two connections using the independent t-test, which was evaluated at 0.05 significance level. Also, this study measured strain around the implant–abutment joint area at an in vitro bone model setting under 100,000 cyclic loading

3. Results

Mean changes of DIB from baseline to 1-year loading were 0.59 ± 0.95 mm for the external, and 0.01 ± 0.68 mm for the internal connection. Although no significant differences were found between two groups in the change of PA and DIB, medium effect size was found in DIB between the connections (Cohens d=0.67). The internal friction connection displayed higher values of strain than the external hex connection. Internal friction connections strain was measured 993 µm/m and external connection registered 904 μm/m.

4. Conclusions

Within the limitation of this study, the results of this one-year comparative clinical trial suggested the possibility of internal friction connection in more effective preservation of marginal bone despite of no significant differences in the bone level between the implant-abutment connection structures, considering the effect size in the vertical bone level change.

Keywords: Clinical trials

Bone implant interactions

Periodontology

Implant–abutment connection

Marginal bone level

Student Number : 2016-29016