Effects of masticatory muscle function affected by BTX on maxillofacial bone growth through the sutural modification

Botulinum toxin type A injection into the masticatory muscles and its effects on mandibular bone resorption and density. A systematic review

OBJECTIVE

This systematic review aims to summarize and synthesize the evidence that investigates the secondary effects of the application of botulinum toxin (BT) into the masticatory muscles and its effects on bone density.

MATERIALS AND METHODS

Database searches were conducted until March 19th, 2024. The quality of the studies was assessed by the Cochrane tool risk of bias for the randomized controlled trials and the ROBINS-I tool for non-randomized studies. The Cochrane Grading of Recommendations Assessment Development and Evaluation (GRADE) was used to evaluate the confidence in the overall evidence.

RESULTS

Five studies looking at the effects of botulinum toxin on bone density and resorption when applied to masticatory muscles were found. No significant changes were observed in most of the studies when looking at the effects of botulinum toxin on mandibular condyle volume, density, mandibular angle thickness, and coronoid process volume. The only finding that was statistically and clinically relevant was the difference between patients who received a double application of BT when compared with patients who received a single application (SMD: -0.99 [95%CI: -1.94,-0.05]) on the volume of the mandibular angle.

CONCLUSIONS

There is no clear pattern on whether the application of botulinum toxin is associated with bone resorption or not. Although some studies show statistical significance of the findings, the magnitude of the changes in bone density and their clinical significance are not completely clear.

CLINICAL RELEVANCE

To understand the effectiveness of the use of botulinum toxin into the masticatory muscles and its possible secondary adverse effects on the density of the mandible.

The role of craniofacial maldevelopment in the modern OSA epidemic: a scoping review

STUDY OBJECTIVES

There is increasing recognition that environmental factors affect human craniofacial development and our risk for disease. A scoping review of the literature was performed looking at environmental influences on craniofacial development to better understand this relationship and investigate what further study is needed to determine how this relationship may impact obstructive sleep apnea.

METHODS

A comprehensive literature search was performed using the Ovid Medline database from inception to May, 2020 with relevance to craniofacial development in 5 clinically-oriented variables: diet, secular change, breastfeeding/non-nutritive sucking habits (NNSH), nasal obstruction/mouth breathing, and masticatory muscle function. The Oxford Centre for Evidence-Based Medicine Levels of Evidence (LoE) was used to assess studies based on study design.

RESULTS

18,196 articles were initially identified, of which 260 studies were fully reviewed and 97 articles excluded. The remaining 163 articles were categorized as follows: Secular change (n = 16), Diet (n = 33), Breastfeeding/NNSH (n = 28), Nasal obstruction/Mouth breathing (n = 57), and Masticatory muscle function (n = 35). 93% of included studies reported a significant association between craniofacial morphology and environmental factors. The majority of studies were characterized as low LoE studies with 90% of studies being LoE 4 or 5.

CONCLUSIONS

The studies in this review suggest that environmental factors are associated with changes in craniofacial development. However, most studies were heterogeneous and low-level studies, making strong conclusions about these relationships difficult. Future rigorous studies are needed to further our understanding of environmental influences on craniofacial development and OSA risk.