Effects of orofacial applications of low-magnitude, high-frequency mechanical vibration on cranial sutures and calvarial bones: A micro-computed tomography study in rats.

INTRODUCTION: The purpose of this study was to assess the effects of orthodontically aimed low-magnitude, high-frequency mechanical vibration (OLMHFMV) on intact calvarial bone, specifically the parietal and temporal, and cranial sutures, including the sagittal and parietotemporal, of rats in differing stages of growth and development. METHODS: Forty Wistar rats were divided into 4 groups: 2 control groups and 2 OLMHFMV groups. Subsequently, 0.3 cN of force with a frequency of 30 Hz was applied as OLMHFMV on the temporomandibular joint region in the rats in the OLMHFMV-1 group, with the protocol of 20 min/d for 5 d/wk for 1 month, whereas the rats in the OLMHFMV-2 group received mechanical stimuli for 2 months with the same protocol. Morphometric and structural analyses, including suture width, cranial width and height, bone mineral density, bone volume/tissue volume, trabecular number, trabecular separation, and trabecular thickness analyses, were carried out using micro-computed tomography. RESULTS: The width of the parietotemporal and sagittal sutures and the cranial height and width increased significantly by OLMHFMV (P <0.021). The structural analysis revealed that trabecular number and trabecular separation increased, whereas trabecular thickness decreased in the OLMHFMV groups compared with the control groups (P <0.048). Bone volume/tissue volume remained unchanged despite reducing the bone mineral density of the OLMHFMV groups. CONCLUSIONS: OLMHFMV had a potential for modulating sutural and cranial growth in adolescent rats. OLMHFMV increased the structural quality of the temporal and parietal bones. These effects may have clinical implications as a treatment option for patients suffering from craniofacial anomalies such as craniosynostosis or a supportive approach for dentofacial orthodontic treatments.

The Effect of Bimaxillary Surgery on the Airway Morphology in Class III Patients: Taking Into Account the Head Posture During Walking.

OBJECTIVES: To assess changes in head and neck posture, airway, hyoid, tongue, and soft palate in skeletal class III individuals whose cephalograms were taken using dynamic natural head positioning method with an inclinometer. MATERIALS AND METHODS: This study was conducted on 20 class III patients operated with double jaw surgery. Natural head positions were determined before and 6 months after the surgery. Craniocervical, pharyngeal airway, tongue, and hyoid positions were measured. In the analysis of the data, paired t test, independent sample t test and correlation tests were used. RESULTS: There was a statistically significant change in the craniocervical measurements with the operation and the head position was further extended (P < 0.05). Significant changes were observed in the soft palate angles upon surgery (P < 0.026) and the increase in oropharyngeal airway area was statistically significant (P < 0.001). There was a statistically significant increase in tongue length (TL) and distance from vertical reference plane to tongue tip (TTi/VRP) measurements (P < 0.001 and P < 0.012, respectively). There was a statistically significant decrease in distance from horizontal reference plane to tongue tip (TTi/HRP) and tongue dorsum (TD/HRP) measurements (P < 0.033 and P < 0.003, respectively). The only significant change among the hyoid bone position-related measurements was distance between hyoidale and epiglottis (P < 0.013). CONCLUSIONS: Hyoid bone location, tongue measurements, and posterior pharyngeal airway were found to be related to each other and they have been found to be effective on the head and neck posture. Head position will be affected by possible surgical alternatives.