Purpose: The aim of this study was to investigate and compare the survival rate and the success rate of single tooth implants placed and restored immediately after extraction in non-infected, acutely infected, and chronically infected sites in the maxillary anterior area. Material and methods: Patients requiring single tooth replacement of a maxillary central incisor, lateral incisor, canine, and premolar regions were included in the study. Implant sites were divided into three groups based on the presence or absence of an infection: Group 1 (Control) non-infected sites (healthy periodontal and endodontic conditions); Group 2 (Test 1) acutely infected sites (presence of a periodontal or endodontic or combined abscess and/or fistula); Group 3 (Test 2) chronically infected sites ( presence of a periodontal pocket or a periapical lesion with no signs of acute inflamation). The protocol applied required: flapless extraction, thorough debridement of the alveolus, immediate placement of the implant, particulate graft material insertion around the implant, resorbable membrane insertion in the facial aspect of the implant for all those cases in which the buccal plate was compromised, and immediate insertion of a screw-retained provisional FDP out of occlusion. The following parameters were evaluated: Periodontal and Endodontic initial conditions: gingival recession, probing depth, presence of an abscess and/or a fistula, extraction reason, presence of a periapical lesion, alveolar buccal wall integrity, distance between the gingival margin and the alveolar bone crest at mid-buccal, and implant insertion torque. Implant conditions at the last follow up included survival rate and marginal bone loss. Periodontal conditions: recession, probing depth, and gingival index. Final esthetic results: pink esthetic score. Statistical analysis was also performed. Results: After a mean follow-up of 7 years (range 2 to 12 years), a total of 127 patients were treated, 143 single tooth implants were placed and immediately restored with a provisional FDP: 47 implants in Group 1 control (non-infected sites), 56 implants in Group 2 Test 1 (acutely infected sites), 40 implants in Group 3 Test 2 (chronically infected sites). A survival rate of 97.8% for Group 1, 96.4% for Group 2, and 95% for Group 3 were recorded with no statistical difference between groups (p-value 0.8). A total of 5 implants failed, one in Group 1, two in Group 2, and two in Group 3 resulting in a cumulative implant survival rate of 96.5%. Conclusions: The results of this study showed comparable implant survival rate between single tooth implants placed and restored immediately in a non-infected, acutely infected or chronically infected site.
Keywords: infected site, periodontal abscess, single tooth implant, extraction sockets, immediate placement, acute infection, chronic infection.