Implant-assisted complete prostheses.

The current review was undertaken to obtain a better understanding of the knowledge base of implant-assisted complete dental prostheses (fixed and removable) in the treatment of the completely edentulous maxilla or mandible. Indications, advantages and disadvantages, complications and maintenance issues, as well as the cost-effectiveness of both treatments, are discussed to help clinicians in their therapeutic decision-making. In summary, when indicated and depending on the patients' needs, both removable and fixed implant-assisted prostheses are highly safe, reliable and satisfactory treatment modalities for the rehabilitation of edentulous jaws. Careful and precise treatment planning is highly recommended to assist the clinician in preventing potential prosthetic failures. The review also reveals that there is still a need for data, generated using robust research methods, on some patient-based and clinical outcomes.

Long-term randomized clinical trial evaluating the effects of fixture surface acid-etching and machined collar design on bone healing.

OBJECTIVES: An implant with an acid-etched fixture surface and internal-hex collar may achieve greater osseointegration. The goal of this research was to study the effects on long-term bone healing of fixture surface acid-etching and machined collar design. METHOD AND MATERIALS: Three two-part implant types were compared: standard Brånemark (with an external-hex 1.2 mm long machined flat collar), Swede-Vent (a copy of the Brånemark design, with an identical collar but a fixture surface acid-etched to 1 to 3 µm), and Screw-Vent (with a fixture surface acid-etched identically to that of Swede-Vent, but a longer internal-hex machined flat collar that did not require countersinking). Fifty-eight subjects each received the three types in alternate fashion at five sites between mental foramen, and a fixed full-arch prosthesis. Abutment-implant interface/microgap (MG) was placed at the crest, and first bone-to-implant contact point-to microgap (fBIC-MG) was measured at mesial and distal sides of each implant. Mean fBIC-MG values were compared after 15 to 20 years of function. Statistical analysis was based on the mixed linear model with the level of significance set at P < .05 and Bonferroni correction for pairwise comparisons. RESULTS: Brånemark had less mean marginal bone loss (-1.08 mm, standard error [SE] 0.20) compared with Swede-Vent (-1.28 mm, SE 0.20), but pairwise comparisons showed that the difference was not statistically significant (mean difference of 0.20 mm, P = .662). Screw-Vent had the greatest loss (-1.92 mm, SE 0.20), and pairwise comparisons showed that the difference was statistically significant compared with Brånemark and Swede-Vent (difference ≥ 0.64 mm, P < .001). CONCLUSION: According to accepted standards for osseointegration, all three implant types achieved very acceptable long-term results. However, while Brånemark had the least bone loss, the implant with the acid-etched fixture surface and longer internal-hex collar design had the greatest loss. Within the confines of this study, shorter collar length of 1.2 mm may be more important to limit long-term bone loss with microgap placed at the crest.