Therapeutic Potential of Low-level Laser Photobiomodulation on Adjuvant Induced Temporomandibular Joint Arthritis in A Rat Model

Abstract

Objective: To test the efficacy of low-level laser therapy (LLLT) to alleviate temporomandibular TMJ induced arthritis in rats. Materials and methods: Rats were randomly allocated to three groups: group I (sham control), group II (arthritis) where animals were subjected to arthritis induction using complete Freund's adjuvant followed by LLLT (0 j/cm 2 ), and group III (LLLT) where animals were subjected to arthritis induction followed by LLLT (38 j/cm 2 ). One and three weeks after treatment onset, rats were euthanized and specimens were subjected to histological, histomorphometric, and histochemical analysis. Results: The sham group showed normal histology. The arthritic group showed severe changes with surface irregularity, loss of condylar zones, hypocellularity, and bone resorption. The articular disc was significantly increased in thickness (P=0.0005), while the condylar cartilage was atrophied (P<0.0001). LLLT treatment caused significant enhancement of disc (P<0.0001) and cartilage thickness (P=0.0001) compared to the arthritic group after three weeks. The histological structure of TMJs appeared more regularly arranged than the arthritis group with better results after three weeks, where articular surfaces showed uniform outlines, chondrocytes were well arranged, less osteochondral detachment was detected, and subchondral bone showed arranged trabeculae. However, LLLT did not restore complete normal architecture as compared to the sham group. Conclusions: LLLT can significantly promote the regeneration and healing of arthritic TMJs. However, longer follow-up periods or different laser doses may be recommended to restore normal tissue architecture.

Photobiostimulation conjugated with stem cells or their secretome for treatment of temporomandibular joint arthritis; a comparative study

“…In a previous study, we managed to test the e cacy of LLLT on induced TMJ arthritis in rats, and the results showed signi cant amelioration of arthritic changes. However, complete restoration of the normal histological architecture was not achieved (10).…”

“…Sample size was calculated using G*power version 3.1.9.4 based on the mean thickness of the TMJ articular disc among the studied groups retrieving the control and arthritis groups from a previous study (10). With 2.715 as effect size, 2-tailed test, 0.05 α error and 90.0% power, the calculated total sample size was at least ve in each group.…”

“…Rats were anesthetized by halothane inhalation (4-5%) in a closed tube, then TMJ regions were shaved and wiped with Betadine. The TMJ area was palpated, and intra-articular injection was performed following our previous protocol (10). PBS, CFA, ADSCs or secretome were injected according to the intervention of each group (Fig.…”

Evaluating the effectiveness of low-level laser therapy in reducing local anesthesia injection pain in children

“…Due to the analgesic effect of laser, researchers studied the effect of LLLT diode laser in reducing the injection pain associated with dental local anesthesia. Previous studies used different pain scales; either modi ed behavioral pain scale (MBPS) [14], or FACES Scale [15], or visual analog scale (VAS) [16] [9] [17] [14], or Face, Legs, Activity, Cry, Consolability (FLACC) scale [10]. In our study FACES Scale was adopted because it shows a close linear relationship with visual analogue pain scales for kids of age and older.…”