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AO JOMI News: Implant-abutment interface configuration effects on dental implant therapy

Dec. 11, 2014
In a recent study published in The International Journal of Oral and Maxillofacial Implants (JOMI, published by Quintessence), the official journal of the Academy of Osseointegration, scientists evaluated the peri-implant tissue response around different implant-abutment interface configurations when compared side by side. They analyzed two different soft-tissue adaptation variables and three different microgap interface variables.

Canine study finds implant-abutment interface configuration may influence crestal bone changes

This study was published in the September/October issue of The International Journal of Oral and Maxillofacial Implants (JOMI), the official journal of the Academy of Osseointegration (AO).

"This report provided clinicians and scientists with a strong dataset from an experienced investigatory team that considers an important issue in clinical implant dentistry. Distinct responses were observed at different interfaces with little bone loss revealed at the one-piece straight implant. The significant differences observed between one piece (no interface) straight and concave interface designs raises important questions about the role of horizontal offset and requires more careful investigation of the biology of the tissue responses at this important tissue interface in clinical dentistry,” — Lyndon Cooper, DDS, PhD, Academy of Osseointegration board member and professor, UNC School of Dentistry

Background: Current implant protocols require not only osseointegration, but also high levels of soft-tissue stability and esthetics. Crestal bone changes and their impact on soft-tissue architecture are the most unpredictable and undesirable consequences of implant therapy, especially in the anterior maxilla. Hypotheses about the etiology of crestal bone remodeling around dental implants can be categorized into three main proposals: (1) mechanical factor that will disturb the surrounding tissues when occlusal forces are transmitted through the prosthetic component to the implant; (2) peri-implant inflammatory cell infiltrate caused by bacteria located at the implant/abutment microgap that will trigger crestal bone changes; and (3) adaptive response of the biologic width to the local condition not related to stress factors or inflammatory factors.

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Key point: In this study, prototype test implants were fabricated to combine all current microgap and abutment profile variables. All implants integrated, and there were no biologic or technical complications. The one-piece, nonsubmerged implant design with a straight profile demonstrated the least crestal bone remodeling. Implant-abutment connections with a concave profile established crestal bone levels immediately apical to the concavity, regardless of the microgap variable.

Author: Dr. Santiago J. Caram, Department of Prosthodontics, Dental School, National University of Cuyo, Mendoza, Argentina, and Colleagues

Purpose: Scientists aimed to evaluate the peri-implant tissue response around different implant-abutment interface configurations when compared side by side. Two different soft-tissue adaptation variables and three different microgap interface variables were analyzed.

Materials and methods: Six different experimental implant abutment design groups — A to F — were evaluated in six mixed-breed dogs: (A) straight/matching; (B) straight/nonmatching; (C) straight/one-piece; (D) concave/matching; (E) concave/nonmatching; and (F) concave one-piece. At month 0, implant placement was performed and baseline standardized radiographs were taken. After three months of healing, standardized radiographs were taken and preformed titanium crowns were screw-retained to the top part of the abutments. Radiographs were taken every month for a period of six months. Dogs were fed a soft diet and implants were cleaned once each week with chemical and mechanical plaque control.

Results: All implants (72) integrated successfully and remained stable during the entire study period. When comparing radiographs of groups with straight profiles, crestal bone remodeling in Group C (one-piece design), was significantly less than in Group A (matching diameters) and Group B (nonmatching diameter). Implant Group C (one-piece design) showed the least crestal bone remodeling of all groups. When comparing radiographs of groups with a concave profile but different microgap configurations, all three designs demonstrated bone loss with no significant differences among the three groups.

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More information: To join AO and begin receiving JOMI (bi-monthly) or obtain online access to JOMI, visit:

About The International Journal of Oral & Maxillofacial Implants —
This highly regarded, frequently cited journal integrates clinical and scientific data to improve methods and results of oral and maxillofacial implant therapy. It presents pioneering research, seminal studies, emerging technology, position papers, and consensus reports, as well as the many clinical and therapeutic innovations that ensue as a result of these efforts. The editorial board is composed of recognized opinion leaders in their respective areas of expertise and reflects the international reach of the journal. Under their leadership, JOMI maintains its strong scientific integrity while expanding its scientific influence within the field of dentistry. It is published by Quintessence Publishing and is the official journal of the Academy of Osseointegration.

About the Academy of Osseointegration —
With 6,000 members in 70 countries around the world, the Academy of Osseointegration (AO) is recognized as the premier international association for professionals interested in implant dentistry. AO serves as a nexus where specialists and generalists can come together to evaluate emerging research, technology and techniques, share best practices, and coordinate optimal patient care using timely, evidence-based information. Follow AO on Facebook and Twitter.