Crestal bone loss associated with different implant surfaces in the posterior mandible in patients with a history of periodontitis. A retrospective study.

OBJECTIVE: To retrospectively assess the interproximal bone loss (CBL) in external hexagon implants (EHI), with different surface micro-topography, placed in the posterior mandible in patients with a history of periodontitis undergoing supportive periodontal care. MATERIAL AND METHODS: 268 consecutive patients received 755 EHI implants in the mandibular molar region between 2007 and 2015 with the following surface characteristics: 72 turned, 145 hybrids (double acid-etched/turned), and 538 anodized. CBL was yearly evaluated by analysing calibrated digital periapical radiographs, with a follow-up of 1-6 years. Data on implant survival were also calculated. RESULTS: At 6 years (53 patients), the mean CBL was 1.34/1.42 mm at patient/implant level, respectively (range: 0-5.2 mm). Significantly higher CBL was detected in anodized implants than in turned and hybrid implants (1.92/1.46/1.02 mm) (p < .01). The maximum CBL values were found in 2 anodized implants at 4 years (6.3 and 8.1 mm). CBL ≥2 mm was detected in 18% of implants at 3 years and 35% at 6 (p < 2.2 × 10-16 ), this prevalence being 2.6 times higher in the anodized than in the hybrid and turned group (40%/15.6%, p < .0094). At 6 years, 25 anodized implants presented CBL ≥3 mm (18%). 6 anodized implants (5 patients) were removed between 4 and 5 years. CONCLUSION: A significant higher CBL was observed in anodized, compared to hybrid and turned implants, when placed in the mandibular molar region of periodontal patients, with a follow-up of 1 to 6 years.

A retrospective study on the crestal bone loss associated with different implant surfaces in chronic periodontitis patients under maintenance.

OBJECTIVE: To analyze retrospectively interproximal crestal bone loss (CBL) on external-hex "non-identical" (NI) dental implants with different surface topography, when placed in the same intra-oral location in patients with a history of chronic periodontitis following maintenance care. MATERIAL AND METHODS: The patient population consisted of 206 consecutive patients with a history of chronic periodontitis who underwent implant surgery between 2007 and 2010; 755 NI implants with different implant surfaces were placed at posterior mandibular sites: 72 machined, 145 acid-etched/machined (hybrid), and 538 anodized. Crestal bone loss measurements were carried out analyzing the calibrated digital X-rays taken at 1-year intervals as part of the maintenance program, being the time of this retrospective examination from 1 to 3 years. RESULTS: At 3 years (51 patients), the mean CBL was 1.36/1.35 mm at implant/patient level (range: 0-6 mm). A higher CBL was observed at anodized surface implants, when compared to machined and hybrid implants, being the mean CBL 1.48, 0.96, and 0.77 mm, respectively (p = .005). CBL between 2 and 3.9 mm was found in 10.6% of the implants at 3 years (95% CI: 6%-15%), ≥4 mm in 5% (95% CI: 2%-8%). Anodized surface implants had CBL >2 mm at 2 years of 9% (95% CI: 6%-12%) and at 3 years of 18% (95% CI: 12%-24%), which were 2.5 times higher than hybrid implants with 3.6% (95% CI: 0.8%-4%) and 7.4% (95% CI: 0%-17%), respectively. CONCLUSIONS: A higher CBL was observed in the anodized surface implants group, when compared to the hybrid implants group in patients with a history of chronic periodontitis followed during 1-3 years.