Quantitative changes of upper airway in class III patients undergoing bimaxillary surgery after one-year follow-up: a retrospective study.

BACKGROUND: Bimaxillary surgery is often performed for class III malocclusion, and its complex influence on the upper airway has been well considered. The aim of this research was to provide a scaled formula between upper airway volume changes and bone movements in Class III patients after orthognathic surgery. MATERIALS AND METHODS: Using a retrospective study design, the investigators enrolled a total of 30 class III malocclusion patients who were undergoing bimaxillary surgery as the study subjects. The subjects included 15 males and 15 females, and their average age was 23.3 ± 3.4 years. CBCT (cone beam tomography) was performed both before and one year after the surgery for each patient. The changes in the soft palate, tongue and upper airway were measured by using CBCT data that was collected before and after surgery. 3D superimposition of CBCT was performed to calculate three-dimensional jaw movements. A multiple regression analysis was used to calculate the quantitative relationship between airway volume changes and jaw movements. RESULTS: The nasopharynx airway volume was observed to be increased by 1064.0 ± 1336.2 mm3, whereas the retropalatal and retroglossal airway volumes were observed to be decreased by 1399.0 ± 2881.6 mm3 and 1433.8 ± 3043.4 mm3, respectively, after the surgery. One millimetre forward and downward movements of the PNS resulted in increases of 626.90 mm3 and 392.18 mm3 in nasopharynx airway volume, respectively. Moreover, one millimetre retrogression of the B point caused decreases of 314.6 mm3 and 656.6 mm3 in the retropalatal and retroglossal airway volume, respectively. The changes in the soft palate contributed to the decrease in the retropalatal airway volume, whereas the tongue compensated for the decrease in the retroglossal airway volume. CONCLUSION: The movements of the PNS and B points could be used to predict upper airway volumetric changes in Class III patients after maxillary advancement and mandibular setback.

Diagnostic efficacy of CBCT, MRI, and CBCT-MRI fused images in distinguishing articular disc calcification from loose body of temporomandibular joint.

OBJECTIVES: To evaluate the diagnostic efficacy of CBCT-MRI fused images for articular disc calcification of temporomandibular joint (TMJ). MATERIALS AND METHODS: Twenty patients (24 TMJs) whose image examinations showed dense bodies in the TMJ space were included in the study. The locations of dense bodies evaluated by the three experts were used as a reference standard. Three oral and maxillofacial radiology residents evaluated whether the dense bodies were disc calcification or not, with a five-point scale for four sets of images (CBCT alone, MRI alone, both CBCT and MRI observed at a time, and CBCT-MRI fused images) randomly and independently. Each set of images was observed at least 1 week apart. A second evaluation was performed after 4 weeks. Intraclass correlation coefficients were calculated to assess the intra- and inter-observer agreement. The areas under the ROC curves (AUCs) were compared between the four image sets using Z test. RESULTS: Ten cases were determined as articular disc calcifications, and fourteen cases were recognized as loose bodies in the TMJ spaces. The average AUC index for the CBCT-MRI fused images was 0.95 and significantly higher than the other sets (p < 0.01). The intra- and inter-observer agreement in the CBCT-MRI fused images (0.90-0.91, 0.93) was excellent and higher than those in the other images. CONCLUSIONS: CBCT-MRI fused images can significantly improve the observers' reliability and accuracy in determining articular disc calcification of the TMJ. CLINICAL RELEVANCE: The multimodality image fusion is feasible in detecting articular disc calcification of the TMJ which are hard to define by CBCT or MRI alone. It can be utilized especially for inexperienced residents to shorten the learning curve and improve diagnostic accuracy.

A three-dimensional study of hemimandibular hyperplasia, hemimandibular elongation, solitary condylar hyperplasia, simple mandibular asymmetry and condylar osteoma or osteochondroma.

PURPOSE: To investigate the morphological features of hemimandibular hyperplasia (HH) in comparison to other condylar hyperplasia-associated asymmetries, including hemimandibular elongation (HE), solitary condylar hyperplasia (SCH), simple mandibular asymmetry (SMA) and condylar osteoma or osteochondroma (COS). MATERIALS AND METHODS: A total of 31 HH, 9 HE, 6 SCH, 10 SMA and 10 COS patients were included in this study. Clinical documentation, panoramic radiography and computed tomography data were retrospectively reviewed. The three-dimensional measurements were performed on multi-planar reformation images and volume rendering images. The accuracy of the subjective radiological signs was evaluated using sensitivity, specificity and receiver operating curve analysis. Discriminant analysis was performed to generate predictive formulas using quantitative data. RESULTS: The condyles in HH were regularly or irregularly enlarged, with significantly enlarged anterior-posterior length [16.2/5.29 (mean/SD, mm) P < 0.001] and volume [5.3/2.9(mean/SD, cm3) P < 0.001] compared to the normal values. The condyles in HE and SMA were normally shaped, and the quantitative measurements were within the normal range. The ramus heights in the HH patients [55.7/5.4(mean/SD, mm)] were enlarged in comparison to the contralateral side (P < 0.001) and normal values (P < 0.001). The ramus heights in the HE [52.4/7.1 (mean/SD, mm), P < 0.001] and SMA [50.3/5.0(mean/SD, mm), P = 0.002] patients were enlarged in the contralateral side comparison but were within the normal range. The mandibular body heights in HH were enlarged in the premolar [16.6/1.3 (mean/SD, mm), P < 0.001] and molar [24.8/1.4 (mean/SD, mm), P < 0.001] regions. The inferior convexity of the lower mandibular border and inferiorly displaced mandibular canal produced high specificity, sensitivity and area under the curve for the diagnosis of HH. Discriminant analysis could predict the diagnoses with a cross-validation accuracy rate of 85.7%. CONCLUSIONS: HH is a distinct clinical entity characterized by enlargement of the condyle, ramus and mandibular body. The inferior convexity of the lower mandibular border and inferiorly displaced mandibular canal is accurate and specific for the diagnosis of HH. The condyles in HE are not hyperplastic. The term "condylar hyperplasia" alone cannot be used to refer to HH or HE.

Congenital infiltrating lipomatosis of the face: A subtype of hemifacial hyperplasia.

OBJECTIVE: To investigate the clinical, imaging and pathological features of congenital infiltrating lipomatosis of the face (CILF) and to discuss whether it is a subtype of hemifacial hyperplasia (HH). METHODS: Sixteen patients diagnosed with CILF were included in this study. All patients had undergone panoramic radiography and spiral CT examinations. Thirteen patients received biopsy, surgery treatment and pathological examination. The clinical documentation and imaging data were retrospectively reviewed. RESULTS: The cheeks (14/16), parotid glands (12/16), tongues (9/16), masticatory muscles (8/16) and the lips (7/16) were the most frequently affected soft tissue organs. The maxilla (14/16), zygoma (13/16), mandible (13/16) were involved among the maxillofacial bones. Dental malformations included macrodontia (8/16), poor formation of the roots (7/16), accelerated tooth germ development or premature eruption of permanent teeth (7/16) and missing of the permanent teeth (4/16). All malformations were restricted to one side of the face and did not trespass the middle line. Pathologically, CILF was featured by the diffuse infiltration of redundant mature adipose tissue into the tissue of the affected organ. CONCLUSION: CILF is a congenital developmental facial malformation characterized by infiltration of nonencapsulated, mature adipose tissue, resulting in facial soft and hard tissue hypertrophy and dental malformations in hemifacial structures. CILF could be considered as a subtype of HH.