Investigation of structural changes in temporomandibular joint after botulinum toxin injection in rats with experimental osteoporosis

Osteoporosis (OP); is a skeletal systemic disease that is characterized by decreased bone mineral density, impaired bone quality and significantly increases the risk of fracture. It usually occurs with spontaneous fractures in postmenopausal women. Osteoporosis alsocauses significant changes in the maxillofacial area. Botulinum toxin; is a powerful neurotoxin synthesized by Clostridium botulinum, gram-negative, anaerobic and spore-forming bacteria. It is known that degenerative changes occur in the temporomandibular joint (TMJ) and bone quality in the mandibular condyle area after botulinum toxin applications in the masseter muscle. In this study, it was aimed to investigate the changes in TMJ region after botulinum toxin application to masseter muscles with the experimental creation of OP in rats. In our study, 20 female Wistar Albino rats were divided into two experimental groups (n: 10). The OP disease model was created by administering retinoic acid by gavage to the rats in the first experimental group once a day for 14 days. In the second experimental group, the same amount of sterile saline was given by gavage for 14 days. A single dose of 12U / 0.1 cc botulinum toxin was injected into the right masseter muscles of the rats in both experimental groups. Sterile saline in a volume of 0.1 cc was injected into the left masseter muscles of the rats. All rats were sacrificed 4 weeks after the injections. Bilateral mandibular condyle samples were excised. Samples were analyzed at elemental level by XRF-Spectrometric method. When the results of the study were evaluated, it was seen that botulinum toxin administration caused a decrease in Ca levels in the mandibular condyle in rats with OP. However, this decrease was not statistically significant. It was concluded that there is a need for new clinical and animal studies in which the long-term results of botulinum toxin applications performed after the development of osteoporosis are examined and different methods are used in the analysis methods.