Study on Peri-Implant Hard and Soft Tissue with Angulated Branemark Implants

To avoid sinus floor elevations and augmentations dental implants can be placed in an angulated position along the anterior or posterior maxillary sinus and in the mandible premolar section to bypass the mental foramen. The implants can be angulated in an anterior or posterior direction to allow the insertion of longer implants with higher primary stability into the existing bone. The objective of this clinical study was to compare the marginal pen-implant hard and soft tissue health of conventional axial to angulated implants. Patients with axial and angulated Branemark dental implants with the TiUnite surface were examined retrospectively. For the purposes of statistical evaluation, one implant per patient was randomly chosen to avoid intraindividual correlations and subsequent misleading statistical information. Implants were inserted between January 2001 and August 2007. In addition to the usual criterion of pen-implant bone loss, probing depths, oral hygiene and inflammation were evaluated by the following indices: modified Plaque Index (mPI), modified Gingival Index (mGI) and Bleeding on Probing (BOP). The total patient group comprised 62 patients who were treated with 295 implants. Of these, 238 were placed in an axial position and 57 in an angulated position. Half of the patients (n = 31) were treated with axial implants with two to 12 axial implants in the premolar and molar areas and a few patients had additional implants in the anterior region. Due to the statistical selection from 61 patients, 31 axial implants with an average follow-up period of 4.1 +/- 1.1 years and 30 angulated implants with an average follow-up period of 2.4 +/- 1.1 years, in both the premolar and molar sites, were evaluated. Regarding the success criterion of pen-implant bone loss of Smith and Zarb (1989), angulated implants show a cumulative success rate (CSR) of 90% compared to 97% of axial implants. However, the difference was not significant. Regarding all other parameters, no negative consequences were observed. At the surface of the implant, which is angulated to the bone, no increased probing depths and no signs of marginal inflammation were noticed. Angulated implants are a reliable method to avoid augmentation. With regard to the evaluated parameters, no difference between axial and angulated implants could be ascertained.