Effect of bisphosphonate on temporomandibular joint in osteopenia-induced rats by botulinum toxin A injection on masticatory muscle: a preliminary study

Abstract

Background Botulinum toxin injection on the masticatory muscle induces the osteopenic condition on the ipsilateral condyle. Bisphosphonate suppresses bone resorption and is used to treat osteopenic or osteoporotic condition. This study aimed to evaluate the effect of bisphosphonate administration on prevention of condylar resorption and botulinum toxin A-induced disuse osteopenia in rats. Results The volume of the condyle and bone volume/tissue volume (BV/TV, %) showed a strong tendency towards statistical significance ( p = 0.052 and 0.058). Trabecular thickness (Tb.Th, mm) and trabecular number (Tb.N, 1/mm) were significantly smaller in the Botox group than in the other groups ( p < 0.05). The volume of the condyle and BV/TV in the bisphosphonate 100 and bisphosphonate 200 groups showed similar values when compared with the control group. Conclusion Bisphosphonate administration after botulinum toxin A injection in the masticatory muscles appears to prevent condyle resorption and botulinum toxin-induced disuse osteopenia in rats.

Effect of Injection Botox in Masseter Muscle on Morphometric Measurements of The Mandible in Sprague Dawley Rats

“…Out of all the minimally invasive procedures available in the market today, botox is the most widely used product for cosmetic purposes. 11 The use of botox appears to be the most common minimally invasive procedure conducted by plastic surgeons and has developed into a billion dollar industry over the past decade. 12 Durand et al, supported the idea that repeated type A botulinum toxin injection is likely to be responsible for both therapeutic and unintentional atro-phy of the muscle with 30% masseter muscle reduction after 3 months of injection and up to 13.4% reduction in muscle volume even after restoring the muscle function using electromyographic data.…”

“…This observation was reinforced by a previous study of Kim et al which yielded insignificant results for all the parameters (trabecular thickness, bone volume and condylar volume) when control group was compared with sham injected masseter muscle on the opposite side of the experimental side. 11 At the beginning of the experiment, the rats were 10 weeks old. They were still in their growing age.…”

“…In the sham group, same dosage of normal saline was administered on the left side of the masseter muscle. 11 Using Triple beam balance, initial and final animal weights were recorded. By measuring the difference between final weight and initial weight, total body weight shift was derived.…”