Combined effect of photobiomodulation with a matrix metalloproteinase inhibitor on the rate of relapse in rats

Abstract

Objective: To investigate combined effect of photobiomodulation with a matrix metalloproteinase (MMP) inhibitor on the relapse rate in relation to MMP expression in rats. Materials and Methods: Fifty-two rats were divided into four groups according to the treatment modality: control group, irradiation group, doxycycline group, and irradiation with doxycycline group. During a relapse period of 5 days after orthodontic movement, maxillary central incisors were treated by low-level laser therapy (LLLT) as a photobiomodulation and/or doxycycline as a synthetic MMP inhibitor. Relapse rate was evaluated in association with MMP expression at the gene and protein levels. Results: Relapse rates were increased by LLLT (1.57-fold) and decreased by doxycycline (0.83-fold) compared with the control, showing positive correlation with the levels of expression for all MMPs in the periodontal ligament (PDL). LLLT concomitant with doxycycline administration resulted in no significant differences of relapse rate and MMP expression from the control. Conclusions: The combined effect of photobiomodulation with an MMP inhibitor around the relapsing teeth proved to be antagonistic to PDL remodeling activity during relapse. This study suggests a basis for developing a novel biologic procedure targeting the MMP-dependent PDL remodeling to control the relapse rate. (Angle Orthod. 2016;86:206-213.)

Effect of pharmacological agents on relapse following orthodontic tooth movement:

“…The search identified a total of 2354 studies, of which 1633 studies were screened for titles and abstracts after the removal of duplicates. From the remaining 10 records that were assessed for eligibility, 3 studies were excluded because one included a period of retention before experimental relapse, 18 1 involved animals with pathological conditions, 19 and the full-text record of 1 study could not be retrieved. 20 Finally, seven studies were included in the qualitative synthesis.…”

Effects of Low-Level Laser Therapy as an Adjunct for Orthodontic Retention: A Systematic Review of Human and Animal Studies

“…Finally, this systematic review included three clinical trials [48][49][50] and ve animal studies [51][52][53][54][55]. Cohen's kappa coe cient values were 0.82 and 0.78 for the above two selection rounds, indicating a substantial agreement between the two reviewers.…”

“…Only tooth relapse and dental health in terms of root resorption were investigated out of all post-OTM outcomes, and no studies reported any impacts of LLLT on patients' subjective perceptions. For orthodontic relapse, two of the studies were CCTs [48,49] and the others were animal experiments [51][52][53]. These studies covered two types of tooth movement, rotational and transitional relapse.…”

“…Two CCTs [48,49] and three animal studies [51][52][53] ful lled the inclusive criteria investigating the effects of LLLT on post-OTM stability of tooth position, and the results they documented were inconclusive. Detailed information from all studies on post-OTM stability is summarised in CCT: clinical controlled trial; SMD: split-mouth design; N: number of participants; n: number of evaluated teeth; FA: xed appliances; CSF: circumferential supr metalloproteinase; LLLT: low-level laser therapy Table 1 Characteristics of included studies on orthodontic relapse…”

“…The animal studies investigating the effects of LLLT on post-OTM tooth stability include one that assessed rotation [51] and two that observed transitional movement [52,53] in rodent and canine models, respectively.…”