Redo of dental implants has a lesser survival rate compared with previous reports for implants in pristine sites. These results were not associated with most implant- and/or patient-related factors. Thus, a possible negative effect that is associated with the specific implant's site might account for this phenomenon.

Ridge preservation using bovine derived xenograft might reduce sinus pneumatization along with minimizing crestal bone resorption.

Objective: To evaluate radiographic measurements for use as prognostic indicators for healing of class II furcation defects following regenerative therapy. Material and Methods: In 17 patients (eight females), 33 class II furcation defects (mandibular buccal (n 5 10) and lingual (n 5 12), and maxillary buccal (n 5 11)) were treated using the barrier membrane technique. Twenty-six furcations were treated using a bioabsorbable membrane, while a nonresorbable membrane was used to treat the remaining seven furcation defects. Clinical parameters and standardized radiographs were obtained before as well as 6 and 24 months after therapy. All radiographs were digitized and evaluated by an examiner blinded to the clinical data. The following distances were measured: cemento-enamel junction line (CEJ-line) to alveolar crest (AC) at the furcation site (AC-CEJ line), CEJ-line to the furcation fornix (Fx-CEJ line), width of the furcation at the level of the AC (FW) as well as the distance from Fx to a straight line between the AC mesial and distal of the tooth (Fx-AC line). Results: Statistically significant (po0.001) horizontal attachment gains could be observed 6 and 24 months after therapy (6 months: 1.49 AE 0.85 mm; 24 months: 1.14 AE 0.91 mm). However, a small but statistically significant (p 5 0.031) attachment loss of 0.35 mm was observed between the 6 and 24 months examination. Multilevel regression analyses identified baseline probing depth (p 5 0.0017) and 3 of the radiographic distances as prognostic factors: Fx-CEJ line (p 5 0.014), FW (p 5 0.0535), Fx-AC line (p 5 0.0827). Conclusion: The analysis of presurgical radiographs may yield information on the success of the regenerative therapy of buccal and lingual class II furcation defects. A long root trunk, a wide furcation entrance and an Fx coronal to the AC have negative influences on the success of therapy. Further, a deep probing depth at the furcation site at baseline increases the likelihood for more favourable horizontal attachment gain in furcations.