Histomorphometric evaluation of the effect of local and systemic application of boric acid on bone healing in rats

In this study, it was aimed to evaluate the short and long term effects of bone regeneration and healing capacity, local, systemic and combination administration as a result of applying boric acid solution locally directly and systemically to the rats with critical size defects created in rat calvaria.In this study, 5 mm diameter critical-sized full thickness defects were created with trefan burs in symmetrical position to the bregma point on the parietal bone in 28 rats. The defects to the left of the skull were left empty, and 3% boric acid solution was applied to the right defects. Boric acid was applied to half of the animals by systemic gavage method. Half of the rats were sacrificed on the 14th day and the other half on the 28th day. In this way, bone samples, which emerged with 8 different applications, were obtained. Different applications were; only systemic application of boric acid, only local application of boric acid, combination of systemic and local boric acid application, and control group. These application variety combined with the two different time periods, resulted in eight experimental groups. The bones were decalcified and evaluated histomorphologically.As a result of the study, boric acid application to the living tissues could be beneficial in preventing excessive amount of connective tissue accumulation and new bone formation. In addition, systemic application of boric acid solution in terms of preventing fibrosis formation ended a statistically significant difference in the 28-day period. On the other hand, combined (systemic and local) application has been shown to reduce systemic effectiveness. When the results are evaluated, it is concluded that boric acid is an effective anti-inflammatory agent and its bone-building effect is limited. Further studies are needed to investigate the effect of different doses on bone formation and fibrosis prevention. Key words: boric acid, fibrosis, critical size defect, bone regeneration