Cone-Beam CT evaluation of upper airway following rapid maxillary expansion and maxillary protraction for the treatment of skeletal class Ⅲ malocclusion / 实用口腔医学杂志

Objective:To analyze the 3D changes of pharyngeal airway in patients with skeletal Class Ⅲ malocclusion after rapid maxillary expansion(RME)and maxillary protraction.Methods:53 patients underwent orthodontic treatment with Hyrax palatal ex-panders and maxillary protraction.Cone-Beam computed tomography(CBCT)scan was taken before treatment(T0),after 1 6 d RME (T1 )and after about 5 month maxillary protraction(T2).Data were reconstructed into 3D model,sagittal and transversal measure-ments,cross sectional areas,volumes of the pharyngeal airway were computed.Results:After RME,the transversal measurements, cross sectional areas,volumes of nasal passage were increased(P <0.05).After maxillary protraction,the 4 nasopharyngeal measure-ments were increased(P <0.05).Conclusion:RME and maxillary protraction may increase pharyngonasal airway.

Cone-beam CT evaluation of nasomaxillary complex and upper airway following rapid maxillary expansion / 中华口腔医学杂志

<p><b>OBJECTIVES</b>To evaluate the naso-maxillary complex width and pharyngeal airway volume changes after rapid maxillary expansion (RME).</p><p><b>METHODS</b>Thirty-five patients were selected (18 males, 17 females, mean age, 12.1 ± 1.1 years). All patients underwent orthodontic treatment with Hyrax palatal expanders. Cone-beam CT (CBCT) scan was taken before treatment (T0), 16 days (T1) and three months (T3) after RME. Naso-maxillary complex width and pharyngeal airway volume were measured.</p><p><b>RESULTS</b>After treatment the width of piriform aperture and maxillary width were significantly increased compared with that before treatment (P < 0.05). Three months after RME, no statistical difference was found in maxillary width compared with that before treatment. The nasopharyngeal volume significantly increased by 29.9% compared with that before treatment (P < 0.05), and the volume remained relatively stable after three months.</p><p><b>CONCLUSIONS</b>RME resulted in a significant increase in the naso-maxillary complex width and nasopharyngeal volume.</p>

Cone-beam computed tomography evaluation of upper airway change in skeletal Class III patients after orthodontic-mandibular setback surgery / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the short-term and long-term effects of pharyngeal airway in mandibular prognathism patients after the combined orthodontic and orthognathic treatment.</p><p><b>METHODS</b>The sample included 28 skeletal Class III patients (13 males, 15 females) who had undergone mandibular setback surgery and orthodontic treatment. Cone-beam CT was taken one week before treatment (T0), 6 months (T1) and 3 years after surgery (T2). Raw data were reconstructed into three-dimensional model. Sagittal and transversal measurements, cross sectional areas, partial and total volumes were computed.</p><p><b>RESULTS</b>Six months after surgery, oropharyngeal volume [(9 021 ± 4 263) mm³], hypopharyngeal volume [(9 236 ± 5 963) mm³] and total volume [(28 619 ± 9 854) mm³] decreased significantly (P < 0.05). Three years after surgery, only sagittal diameters [(15.9 ± 3.5) mm] and cross sectional areas [(996 ± 398) mm²] in the first cervical vertebra plane came back to the original levels (P > 0.05).</p><p><b>CONCLUSIONS</b>The pharyngeal airway space decreased after orthodontic-orthognathic therapy in the short term and it increased in some areas in the long term.</p>

Detection to changes in hyoid and tongue positions, and pharyngeal airway following mandibular setback surgery by cone beam CT / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To observe changes in tongue and hyoid position, and pharyngeal airway in patients with skeletal class III malocclusion after the combined orthodontic and orthognathic treatment.</p><p><b>METHODS</b>Twenty patients were involved in this study. Cone beam CT (CBCT) was performed on patients one week before and six months after treatment. Raw data were reconstructed into three-dimensional model. To set up a three-dimensional reference frame, which was based by point "S", the sagittal and transversal measurements, cross sectional areas, partial and total volumes were computed. The three-dimensional position changes of chin, hyoid bone and tongue were measured in order to analyze the amount of mandibular setback relationship with the changes of pharyngeal airway, hyoid bone and tongue positions.</p><p><b>RESULTS</b>After treatment, the pharyngeal airway was constricted significantly. The hyoid significantly moved inferoposteriorly by 5.72 mm (backward) and 2.76 mm (downward) and the tongue moved posteriorly by 4.04 mm after surgery (P < 0.05). Among the 19 correlated indexes between the amount of mandibular setback and other measurements, 14 of which were significantly correlated (P < 0.05). The strongest correlation was found between the amount of mandibular setback and total volumes of pharyngeal airway (r = 0.834, P < 0.01).</p><p><b>CONCLUSION</b>Following combination therapy, the pharyngeal airway space decreased, the hyoid moved inferoposteriorly and tongue moved posteriorly. There were great correlations between the amount of mandibular setback and the changes.</p>