Influence of bicortical or monocortical anchorage on maxillary implant stability: a 15-year retrospective study of Brånemark System implants

• Published in: The International journal of oral and maxillofacial implants Vol. 15; no. 1; p. 103
• Main Authors: Ivanoff, C J, Gröndahl, K, Bergström, C, Lekholm, U, Brånemark, P I
• Format: Journal Article
• Language: English
• Published: United States 01-01-2000
• Subjects: Adult; Aged; Alveolar Bone Loss - diagnostic imaging; Alveolar Bone Loss - etiology; Dental Abutments - adverse effects; Dental Abutments - statistics & numerical data; Dental Implantation, Endosseous - adverse effects; Dental Implantation, Endosseous - statistics & numerical data; Dental Prosthesis Retention - adverse effects; Dental Prosthesis Retention - statistics & numerical data; Dental Restoration Failure; Female; Follow-Up Studies; Humans; Life Tables; Male; Maxilla; Middle Aged; Radiography; Retrospective Studies; Time Factors
• ISSN: 0882-2786

The present study evaluated implant survival and marginal bone loss in maxillae over a 15-year follow-up period as a function of either monocortical or bicortical implant anchorage. Of 207 standard Brånemark implants (10 mm in length) followed, 110 implants were judged to be monocortically anchored and 97 as bicortically anchored. The bicortically anchored implants failed nearly 4 times more often than the monocortical ones. Implant fractures accounted for over 80% of the observed failures and were found to affect the bicortical group almost 3 times more often. As tentative explanations, induction of increased stress and bending forces resulting from possible prosthetic misfit, presence of unfavorable arch relationships, or high occlusal tables in combination with bicortically anchored implants have been suggested, all indicating an overambitious fixation of the bicortical anchorage. Total marginal bone loss was low over the 15-year period and close to identical for the 2 groups, suggesting that the mode of cortical anchorage did not have any clinically significant influence on marginal bone remodeling.