Antimicrobial and bone repair effects of boric acid in a rat model of dry socket (alveolar osteitis) following dental extraction

Abstract

Background: Alveolitis occurs after dental extraction without blood clot formation, leading to an inflammatory process and bacterial contamination. Boric acid (BA) demonstrates anti-inflammatory, antimicrobial, and osteogenic properties. This study aims to evaluate the possible antimicrobial effects and bone repair of BA in a rat model of alveolitis (dry socket).

Methods: 33 male Wistar rats were submitted to the extraction of the upper right incisor and dry socket induction. They were first divided into two groups: dry socket (n = 17) and dry socket + 0.75 % BA (n = 16). Samples for the microbiological analysis were collected immediately after dental extraction, at the detection of clinical alveolitis, 7, and 14 days after BA application. For microCT and histological analysis, samples from euthanized rats were used in 14 and 28 days after alveolitis detection.

Results: Higher bacterial counts were found in 4-5 days after alveolitis induction, compared to the baseline in both experimental groups, decreasing significantly after 7 and 14 days of treatment with BA (P < 0.05). The microCT evaluation displayed increased bone volume, bone volume fraction, trabecular thickness, and bone mineral density in a time-dependent manner, regardless of BA treatment. On the other hand, the number of trabeculae and total bone porosity decreased over the 28 days of the experiment in the dry-socket group and both groups, respectively (P < 0.05). Histological analysis did not differ on bone repair in both experimental groups.

Conclusion: This was the first report investigating the effects of BA in a rat model of alveolitis regarding microbiological and bone repair aspects. The BA local application decreased the total aerobic and facultative bacteria counts and does not seem to benefit the bone repair after alveolitis development. This study paves the way for more studies involving alveolitis and different BA applications.

Keywords: Alveolar osteitis; Bone tissue; Boric acid; Dry socket; MicroCT; Wound healing.