title: Effects of low-level laser therapy on changes in inflammation and in the activity of osteoblasts in the expanded premaxillary suture in an ovariectomized rat model.
abstract: OBJECTIVE
  Osteoporosis is a progressive systemic skeletal disease characterized by reduced bone mass/density and microarchitectural deterioration of bone tissue. Bone formation initially exceeds bone resorption, but by the third decade, such formation is reversed, resulting in a net loss of bone mass. This resorption, in turn, increases bone fragility and susceptibility to fracture. This study aimed to evaluate the effects of low-level laser therapy (LLLT) on bone regeneration in the expanded premaxillary suture in an ovariectomized rat model.
  
  
  METHODS
  Thirty-two 12-week-old female Wistar albino rats were used in the experiment. All of the animals underwent ovariectomy 3 months before the experiment. Expansion appliances were affixed to the maxillary incisors for the expansion of premaxillary sutures. The premaxillary sutures of the laser group were exposed to 5 J/cm(2) laser energy, and no treatment was performed for the controls. All the rats in both groups were euthanized on either the 7th day (n=8) [end of expansion period; Laser Group 1(LG1) and Control Group 1 (CG1)] or the 17th day (n=8) [end of retention period; Laser Group 2 (LG2) and Control Group 2 (CG2)], respectively, for histological assessment.
  
  
  RESULTS
  Histological findings indicated that the LG1 group showed a significantly higher number of osteoblasts than did the CG1 group (p=0.028). The CG1 and CG2 groups showed a significantly higher number of osteoclasts than did the LG1 and LG2 groups, respectively (p=0.005), (p=0.032). The LG2 group exhibited a capillary increase similar to that of the other groups, without statistically significant differences.
  
  
  CONCLUSIONS
  On the basis of our methodology and results, we conclude that low-level laser associated with rapid maxillary expansion influences bone regeneration in sutures, thereby accelerating healing, even in ovariectomized rats. We found that LLLT decreased osteoclastic activity in the ovariectomized rats. Therefore, preventing osteoporosis necessitates further investigations to clarify the effect of LLLT on postmenopausal patients.
authors.affiliation: 1 Department of Oral and Maxillofacial Surgery, Gaziantep University , Gaziantep, Turkey .
authors.forename: Mutan Hamdi
authors.initials: MH
authors.lastname: Aras
authors.forename: Zehra
authors.initials: Z
authors.lastname: Bozdag
authors.forename: Tuncer
authors.initials: T
authors.lastname: Demir
authors.forename: Rıdvan
authors.initials: R
authors.lastname: Oksayan
authors.forename: Saim
authors.initials: S
authors.lastname: Yanık
authors.forename: Oral
authors.initials: O
authors.lastname: Sökücü
mesh_terms: D000818:Animals; D005260:Female; D007249:Inflammation / Q000532:radiotherapy*; D028022:Low-Level Light Therapy; D010006:Osteoblasts / Q000502:physiology / Q000528:radiation effects*; D010052:Ovariectomy; D010155:Palatal Expansion Technique; D051381:Rats; D017208:Rats, Wistar