Influence of photodynamic therapy on the development of ligature-induced periodontitis in rats.
BACKGROUND
The purpose of this study was to evaluate, histologically and radiographically, the effect of photodynamic therapy on the progression of experimentally induced periodontal disease in rats.


METHODS
Ligatures were placed at the first mandibular molar in rats. The animals were divided into four groups: group 1 (C) received no treatment; group 2 was treated topically with methylene blue (MB; 100 microg/ml); group 3 was treated with low-level laser therapy (LLLT); and group 4 was treated topically with methylene blue followed by LLLT (4.5 J/cm(2)) (photodynamic therapy; PDT). Rats were sacrificed 5, 15, or 30 days postoperatively. Standardized radiographs were taken to measure bone loss around the mesial root surface of the first molar. Data were analyzed statistically (analysis of variance and Tukey test; P <0.05). A scoring system was used to evaluate the connective tissue, periodontal ligament, and alveolar bone histologically. Data were analyzed statistically (Kruskal-Wallis test; P <0.05).


RESULTS
Radiographic examination showed that there was significantly less bone loss in Group PDT compared to Group C at 5 and 15 days postoperatively. There was no significant difference in bone loss at 30 days. At 15 days, the histologic results showed significant differences in the extent of inflammatory reaction in the gingival tissue, with a greater extent of chronic inflammatory reaction in Group LLLT.


CONCLUSIONS
PDT transiently reduced the periodontal tissue destruction.
de Almeida
Juliano Milanezi
JM
Department of Surgery and Integrated Clinic, Division of Periodontics, São Paulo State University Júlio de Mesquita Filho, São Paulo State University, Araçatuba, SP, Brazil.
Theodoro
Leticia Helena
LH
Bosco
Alvaro Francisco
AF
Nagata
Maria José Hitomi
MJ
Oshiiwa
Marie
M
Garcia
Valdir Gouveia
VG
D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000188:drug therapy*; D000704:Analysis of Variance; D000818:Animals; D008026:Ligation; D028022:Low-Level Light Therapy; D008751:Methylene Blue / Q000627:therapeutic use; D010518:Periodontitis / Q000188:drug therapy*; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011859:Radiography; D051381:Rats; D017208:Rats, Wistar; D018709:Statistics, Nonparametric
D017319:Photosensitizing Agents; D008751:Methylene Blue