Topical sodium alendronate combined or not with photodynamic therapy as an adjunct to scaling and root planing: Histochemical and immunohistochemical study in rats

Objective The purpose of this study was to evaluate influence of topical sodium alendronate (ALN), photodynamic therapy (aPDT), or a combination thereof as adjuvant to scaling and root planing (SRP) in the treatment of experimental periodontitis in rats. Background Therapeutic protocols to control periodontitis progression that aim to equalize bacterial action and load with tissue immune response are well addressed in current scientific research. Methods Experimental periodontitis was induced in 96 rats with a ligature around the mandibular left first molar. After 7 days, ligature was removed and animals were treated according to the following experimental groups (n = 8): control—SRP plus saline solution; ALN—SRP plus ALN; aPDT—SRP plus methylene blue irrigation, followed by low‐level laser therapy (LLLT); and ALN/aPDT—SRP plus ALN and methylene blue irrigation followed by LLLT. The animals were euthanized at 7, 15, and 30 days after treatments. Collagen maturation (picrosirius red staining) and immunohistochemical analyses (TRAP, RANKL and osteoprotegerin [OPG]) were performed. Data were submitted to statistical analysis (P