Retrograde peri-implantitis: evaluation and treatment protocols of a rare lesion.

OBJECTIVE: Retrograde peri-implantitis (RPI) is defined as bone loss around an osseointegrated implant apex that usually appears within the first few months of its placement. This retrospective study aimed to evaluate the relationships between RPI and demographic factors, local bone and intraoral factors, and implant and surgery-related factors. METHOD AND MATERIALS: A retrospective study was conducted in 116 patients with a total of 369 implants placed between January and June 2019. The associations between RPI and the following data were evaluated: location of the recipient site, bone quality, reason for previous tooth loss, condition of adjacent teeth, marginal bone loss, immediate or late placement of implants, implant brand and size, activation of lesions, and treatment modality.
Results: Among the 14 (3.8%) implants that showed RPI, 10 (5.8%) were in the maxilla and four (?2.0%) were in the mandible, which were detected before prosthetic loading. There was no significant difference in terms of RPI between the arches. Of the 14 RPI implants, four (28.?6%) were placed into a previously periapical lesion site, three (21.4%) had endodontically treated adjacent teeth, two (14.3%) were immediately placed following extraction, three (?21.4%) revealed marginal bone loss, and one (7.1%) was lost at the abutment connection. Eight RPI implants healed spontaneously, while the remaining six were subjected to treatment (P = .05).
Conclusion: Local bone and intraoral factors, particularly the reason for tooth loss at the recipient site and the condition of the adjacent teeth, had stronger effects on RPI than other factors. (Quintessence Int 2021;52:112-121; doi: 10.3290/j.qi.a45264).

The preventive effect of medicinal herbal extract and gelatin sponge on alveolar osteitis: An in vivo micro-computed tomography and immunohistochemical analysis in rats.

OBJECTIVE: The purpose of this study was to evaluate the preventive effect of medicinal herbal extract (MHE) and gelatin sponge on alveolar osteitis (AO) in an experimental rat model. DESIGN: Twenty-one Sprague-Dawley male rats with a mean age of 12 weeks were used. After extraction of the maxillary right first molar, an AO model was created for each animal. The animals were randomly separated to three equal groups. Group I served as a control, Group II was subjected to an intra-alveolar MHE application, and gelatin sponge was left in the sockets of Group III. On the 7th post-extraction day, the animals were sacrificed. The specimens were analyzed by micro-computed tomography (micro-CT), histopathologically and immunohistochemically. RESULTS: Macroscopic evaluation revealed mild to intense signs of AO in all groups, but the difference was not significant (p < 0.05). Micro-CT analysis showed that bone formation was the highest in Group III (bone volume/total volume; 10.63 ± 4.9 %), whereas bone mineral density was the highest in Group I (2.05 ± 0.2 g/cm3). The difference was not significant (p > 0.05). In Group III, only 16.7 % of specimens showed no signal of inflammatory response (p < 0.01). The difference was not significant between the positive labeling for receptor activator of nuclear kappa-ß (RANK), receptor activator of nuclear kappa-ß ligand (RANKL), osteoprotegerin and osteopontin, but the intensity of Groups II and III was higher than the Group I for osteopontin (p < 0.01). CONCLUSIONS: MHE and gelatin sponge were not effective enough to prevent alveolar osteitis, but positive results were obtained in bone healing.