Five-year outcomes of immediate implant placement for mandibular molars with and without chronic apical periodontitis: A retrospective study

BACKGROUND: Most physicians consider molars with chronic apical periodontitis (CAP) lesions as contraindications for immediate implant placement. At the patient’s request, we perform immediate implant placement of the mandibular molars with CAP in clinical practice. AIM: To retrospectively analyze and compare the 5-year outcomes of immediate implant placement of the mandibular molars with CAP and those without obvious inflammation. METHODS: The clinical data of patients with immediate implant placement of the mandibular molars in the Department of Oral and Maxillofacial Surgery, the Affiliated Hospital of Qingdao University, from June 2015 to June 2017 were collected. The patients were divided into CAP (n = 52) and no-CAP (n = 45) groups. Changes in bone mineral density and bone mass around implants were analyzed 5 years after implant restoration. RESULTS: At 5 years after implantation, the peri-implant bone mineral density was 528.2 ± 78.8 Hounsfield unit (HU) in the CAP group and 562.6 ± 82.9 HU in the no-CAP group (P = 0.126). Marginal bone resorption around implants did not differ significantly between the two groups, including buccal (P = 0.268) or lingual (P = 0.526) resorption in the vertical direction or buccal (P = 0.428) or lingual (P = 0.560) resorption in the horizontal direction. Changes in the peri-implant jump space did not differ significantly between the two groups, including the buccal (P = 0.247) or lingual (P = 0.604) space in the vertical direction or buccal (P = 0.527) or lingual (P = 0.707) space in the horizontal direction. The gray value of cone-beam computed tomography measured using Image J software can reflect the bone mineral density. In the CAP area, the gray values of the bone tissue immediately and 5 years after implant placement differed significantly from those of the surrounding bone tissue (P < 0.01). CONCLUSION: The results of this study suggest that immediate implant placement of the mandibular molars with CAP can achieve satisfactory 5-year clinical results, without significant differences in the complications, survival rate, or bone tissue condition from the no-CAP mandibular molars.