Oral appliance effectively reverses Muller's maneuver-induced upper airway collapsibility in obstructive sleep apnea and hypopnea syndrome.

OBJECTIVES: To verify the effects of oral appliance (OA) on upper airway morphology under intraluminal pressure, identify specific sites of upper airway collapsibility that can be reversed by OAs, and determine the relationship between OA efficacy and dynamic upper airway changes using computed tomography (CT) with Muller's maneuver. MATERIALS AND METHODS: Nineteen adult Chinese patients with symptomatic mild-to-moderate sleep apnea were recruited from our sleep center. Each patient was fitted with a two-piece OA. Dynamic changes in the retropalatal and retroglossal airway were evaluated using CT at end-expiration and during Muller's maneuver, both with and without an OA. RESULTS: Upper airway changes in the end-expiration phase before OA placement did not significantly differ from those after OA placement. However, under intraluminal pressure induced by Muller's maneuver, OA effectively expanded the upper airway at multiple levels. In addition, OA counteracted negative intraluminal pressure more effectively in the retropalatal region than in the retroglossal region, with 95.65, 68.75, 72.41, and 78.38 % improvements in the collapsibility index of the anteroposterior dimension, transverse dimension, minimum cross-sectional area, and volume of the retropalatal region, respectively. Both nonresponders and responders to OA treatment were sensitive to the intraluminal pressure induced by Muller's maneuver. However, the collapsibility of the retropalatal airway improved significantly only in the responders, not in the nonresponders. CONCLUSIONS: OA effectively treats OSAHS by improving upper airway collapsibility.

Osteochondroma of the mandibular condyle: a classification system based on computed tomographic appearances.

OBJECTIVE: The objectives of this study were to introduce the classification of osteochondroma of the mandibular condyle based on computed tomographic images and to present our treatment experiences. MATERIALS AND METHODS: From January 2002 and December 2012, a total of 61 patients with condylar osteochondroma were treated in our division. Both clinical and radiologic aspects were reviewed. The average follow-up period was 24.3 months with a range of 6 to 120 months. RESULTS: Two types of condylar osteochondroma were presented: type 1 (protruding expansion) in 50 patients (82.0%) and type 2 (globular expansion) in 11 patients (18.0%). Type 1 condylar osteochondroma presented 5 forms: anterior/anteromedial (58%), posterior/posteromedial (6%), medial (16%), lateral (6%), and gigantic (14%). Local resection was performed on patients with type 1 condylar osteochondroma. Subtotal condylectomy/total condylectomy using costochondral graft reconstruction with/without orthognathic surgeries was performed on patients with type 2 condylar osteochondroma. During the follow-up period, tumor reformation, condyle absorption, and new deformity were not detected. The patients almost reattained facial symmetry. CONCLUSIONS: Preoperative classification based on computed tomographic images will help surgeons to choose the suitable surgical procedure to treat the condylar osteochondroma.

3D printing of a tough double-network hydrogel and its use as a scaffold to construct a tissue-like hydrogel composite.

To mimic biological tissues with high toughness such as cartilage, it is highly desired to fabricate stable and tough hydrogels with intricate shapes to act as a structural support. Extrusion-based 3D printing is a promising method to fabricate 3D scaffolds with various architectures; however, printing tough hydrogel structures with high fidelity and resolution is still a challenge. In this work, we adopt the fast sol-to-gel transition of κ-carrageenan in the solution of acrylamide upon cooling to fix the printed scaffolds and polymerize the precursor solution to form the second network. The printed constructs of κ-carrageenan/polyacrylamide double-network gels are toughened by soaking in an aqueous solution of zirconyl chloride to form coordination complexes between the Zr4+ ions and sulfate groups of κ-carrageenan. The obtained hydrogels are stable in water and possess good mechanical properties, with a tensile breaking stress of 1-2 MPa, breaking strain of 100-150%, and Young's modulus of 4-10 MPa. The printed grid can hold 150 times its own weight. 3D printed constructs with a high aspect ratio and shape fidelity are obtained by optimizing the printing parameters. Furthermore, a biomimetic strategy is applied to construct a hydrogel composite by filling the printed tough hydrogel scaffold with a cell-laden fibrin hydrogel as the soft substance. Chondrocytes in the hydrogel composite maintain high viability after cyclic compression, demonstrating the load-bearing capacity of the tough scaffold and favorable microenvironment for cells provided by the embedded soft fibrin gel. We envision that this printing strategy for hydrogel constructs with high toughness and good stability, as well as the method to form tough-soft hydrogel composites, can be extended to other systems to develop structural elements and scaffolds towards applications in biomedical devices and tissue engineering.

[Shanghai municipal expert consensus on standardized prevention and control of COVID-19 during procedures of oral radiology].

The announcement of National Health Commission on January 20, 2020 (No.1 of 2020) has included novel coronavirus pneumonia into the B class infectious diseases according to the law of the People's Republic of China on the prevention and control of infectious diseases, and has been managed as A class infectious diseases. People's governments at all levels and health administration departments have been paying high attention to it. With the alleviation of COVID-19 nationwide, dental clinics gradually resume to work. The main transmission routes of COVID-19 are respiratory droplets and contact transmission, hence oral radiological examination is kind of a high-risk operation. Standardized radiologic process is of great significance to reduce the risk of COVID-19 transmission. In accordance with the national and Shanghai epidemic prevention requirements, and in combination with the actual situation of various medical institutions, Oral and Maxillofacial Radiology Committee of Shanghai Stomatological Association formulated the expert consensus on standardized prevention and control of COVID-19 for clinical reference. This recommendation will be updated according to the situation of epidemic prevention and control in China and the new relevant diagnosis and treatment plans.

CT features of synovial chondromatosis in the temporomandibular joint.

OBJECTIVE: The purpose of this study was to determine the characteristic computed tomography (CT) findings of synovial chondromatosis of the temporomandibular joint (TMJ). STUDY DESIGN: Eight subjects with synovial chondromatosis were examined with axial and coronal CT scans. All lesions were histopathologically confirmed either through an arthroscopic punch biopsy or surgery. CT appearances of the lesions were reviewed and classified. RESULTS: Among the 8 subjects, 7 (87.5%) demonstrated soft tissue swelling, 7 (87.5%) showed loose calcified bodies, and 6 (75%) had bony changes of the articular surfaces. Patterns of the skull base changes as well as intracranial extension of the disease were identified. CONCLUSIONS: Based on the CT findings, synovial chondromatosis of the TMJ is characterized by soft tissue swelling, loose calcified bodies, and bony changes of the skull base. The latter may lead to destruction of the central skull base and intracranial extension.

[The radiation-induced jaw osteosarcoma: CT imaging features].

OBJECTIVE: To evaluate the CT features of radiation-induced jaw osteosarcoma(RIJOS) developed after therapeutic irradiation for a variety of nonosseous lesions. METHODS: The demographic and CT findings of thirteen patients with RIJOS were reviewed retrospectively.Observation items included location, bone destruction, mineralized tumor matrix, periosteal reaction, soft tissue extension and calcification.Of the thirteen patients, twelve were male and one was female. The mean age was 48 years (range: 29-68 years).Five patients had tumors in the maxilla and eight in the mandible. All the patients underwent tumor resection. RESULTS: The latent period before development of RIJOS ranged from 3.5 to 14 years (mean, 11 years).In all thirteen patients, eight tumors were osteoblastic, with one osteolytic and four mixed lesions.Osteoid tumor matrix mineralization was present in twelve patients. Periosteal reaction was identified in 11 cases.Soft-tissue extension was present in all patients beyond the area of bone destruction. CONCLUSIONS: The characteristic CT imaging of RIJOS showed the bone destruction associated with a large number of mineralized tumor matrix and significant soft tissue extension in the original radiation field after radiotherapy. CT findings could play an important role in identifying the tumor and pre-operative assessment.

Pigmented villonodular synovitis of the temporomandibular joint: CT imaging findings.

OBJECTIVE: The purpose of this study was to determine the characteristic computed tomography (CT) findings of pigmented villonodular synovitis (PVNS) of the temporomandibular joint (TMJ). STUDY DESIGN: Eight subjects with PVNS were examined with both pre and post contrast CT scans. All lesions were histopathologically confirmed through surgery. CT appearances of the lesions were reviewed. RESULTS: Among the eight subjects, 8 (100%) demonstrated soft tissue mass and enhancement after contrast administration, 6 (75%) appeared as all or focal areas of noncontrast hyperdensity, 6 (75%) had widening of the joint spaces. Bony erosion of the mandibular condyles and articular surfaces were found in 7 (87.5%) and 6 (75%) subjects, respectively. CONCLUSIONS: Based on the CT findings, PVNS of the TMJ is characterized by hyperdensity soft tissue mass and further increase in density after contrast administration, bony destruction of the mandibular condyles and skull base, and intracranial extension.

Local resection of the mass to treat the osteochondroma of the mandibular condyle: indications and different methods with 38-case series.

BACKGROUND: Local resection of the mass was reported to treat the condylar osteochodroma in some cases. The purpose of this study was to evaluate the feasibility and the indications of the local resection. METHODS: In all, 47 patients with osteochondroma of the mandibular condyle were treated from January 2002 to March 2012. The decision to perform local resection depended on 2 factors: there was a stalk existing between the mass and the condyle, and the condylar surface was involved less than 1/2. RESULTS: Local resection of the mass was performed in 38 cases (80.1%). These masses were removed by 4 methods: direct removal (18 cases), pushed-out by a screw and steel wire (14 cases), excision in multiple pieces (3 cases), and temporary osteotomy of the zygomatic arch (3 cases). In the follow-up period, there was no recurrence. CONCLUSION: Local resection of the mass was a more conservative procedure to treat the solitary osteochondroma with a stalk.

Highly monodisperse microporous polymeric and carbonaceous nanospheres with multifunctional properties.

Fabrication of monodisperse porous polymeric nanospheres with diameters below 500 nm remains a great challenge, due to serious crosslinking between neighboring nanospheres during pore-making process. Here we show how a versatile hypercrosslinking strategy can be used to prepare monodisperse microporous polystyrene nanospheres (MMPNSs) with diameters as low as ca. 190 nm. In our approach, an unreactive crosslinked PS outer skin as protective layer can be in-situ formed at the very beginning of hypercrosslinking treatment to minimize the undesired inter-sphere crosslinking. The as-prepared MMPNSs with a well-developed microporous network demonstrate unusual multifunctional properties, including remarkable colloidal stability in aqueous solution, good adsorption-release property for drug, and large adsorption capacity toward organic vapors. Surprisingly, MMPNSs can be directly transformed into high-surface-area monodisperse carbon nanospheres with good colloidal stability via a facile hydrothermal-assisted carbonization procedure. These findings provide a new benchmark for fabricating well-defined porous nanospheres with great promise for various applications.

Measurements of normal upper airway assessed by 3-dimensional computed tomography in Chinese children and adolescents.

OBJECTIVE: To establish normative data of upper airway dimensions in Chinese children and adolescents by age and sex. METHODS: CT-scans of 281 Chinese children and adolescents (140 girls, 141 boys) aged from 6 to 18 years (yr) were selected among the patients who visited in Department of Oral and Maxillofacial Surgery from September 2009 to August 2010. Child was defined as 6-12 yr, and adolescent as 13-18 yr. All the subjects were divided into 4 groups according to age as 6-9, 10-12, 13-15 and 16-18. The upper airway was divided into four distinct anatomic regions: the nasopharynx, the palatopharynx, the glossopharynx and the epiglottic region. Using 3-dimension image processing software, the minimal cross-sectional area with its sagittal diameter and transversal diameter, length and volume of upper airway segmentations were measured. RESULTS: There was no difference in all parameters of segmentations between genders in children. In adolescents the differences of airway parameters were evident between genders. Male adolescents' upper airway were bigger and longer than female's. Volumes and lengths of segmentations were increased with age in male and female respectively. CONCLUSIONS: Norms for upper airway in Chinese children and adolescents assessed by 3-D reconstruction computed tomography have been established. Volume and other dimension of upper airway are increased with age. Significant sex dimorphisms in upper airway dimension are evident in adolescents.

[Preliminary analysis of the bilateral disc-condyle relationship of TMJ before and after prosthetic rehabilitation in edentulous patients].

PURPOSE: To observe the disc-condyle relationship, joint effusion, and osseous abnormalities of the condyle before and after prosthetic rehabilitation in 8 edentulous patients with asymptomatic of bilateral temporomandibular joints (TMJs). METHODS: Complete dentures of 8 edentulous patients were made. Bilateral TMJ MRI before and after prosthetic rehabilitation was performed to observe TMJ internal changes. RESULTS: Before prosthetic rehabilitation, 10 joint disc displacements were found in 62.5% of 16 TMJs of 8 edentulous patients, including 7 medial disc displacement, 2 lateral disc displacement and anterior disc displacement (6.25%); 7 TMJs had effusion 4 had condylar abnormalities. After prosthetic rehabilitation, 10 disc displacements were found in 16 TMJs of 8 edentulous patients, including 7 medial disc displacement, 2 lateral disc displacement, and 1 anterior disc displacement; 7 TMJs effusion. 4 TMJs had condylar abnormalities. CONCLUSIONS: Long-time tooth loss may lead to internal derangement of TMJ in edentulous patients. In short term after prosthetic rehabilitation with complete denture, there is no distinct change in disc-condylar relationship, joint effusion, and condylar abnormalities in edentulous patients.

[Evaluation of disc position in edentulous patients with MRI].

PURPOSE: To detect the condyle-disc relationship with bilateral temporomandibular joint(TMJ) in edentulous patients. METHODS: The study was based on the clinical examination and bilateral MRIs of 11 edentulous patients, the clinical and MRI findings of bilateral TMJ were recorded and the disc position was observed in edentulous patients and the relationship was compared between clinical and MRI findings in those TMJs. RESULTS: It was noted that disc displacement was in 45% of the TMJs in edentulous patients. Four TMJ disc displacement in man was found, accounting for 28.6%,whereas disc displacement was found in 6 TMJs of women, accounting for 75%. CONCLUSIONS: There is no relationship between disc displacement and clinical manifestations. Disc displacement is more frequent in women than in men. There is potential relationship between missing teeth and internal derangement of TMJ in edentulous patients.

[Measurement of the height and width of residual alveolar crests in low-set maxillary sinus patients with missing upper molar].

PURPOSE: Using spiral computed tomography and Simplant software to measure the width and height of residual alveolar crest of agomphious upper molar region at different levels around bottom of low-set maxillary sinus. To evaluate the impact of sex, age, agomphious duration, and cause of tooth extraction on the width and height of residual alveolar crest. METHODS: Forty-three patients with missing uppers molar and residual alveolar bone height being 4 to 6mm showed by panoramic radiographs were scanned by spiral computed tomography. 3D model of the alveolar crest and maxillary sinus were reconstructed using the images from CT scan and Simplant software. The height and width of the residual alveolar crest of agomphious upper molar region at different levels around bottom of maxillary sinus were measured. The data was analyzed with SPSS16.0 software package for Student's t test, analysis of variance(ANOVA) and Kruskal-Wallis H test. RESULTS: (1)The mean distance between the top of residual alveolar crest and the floor of sinus was (5.26±0.58)mm. (2)The difference between the width of internal bone wall and that of external bone wall at different levels above the bottom of maxillary sinus was significant(P<0.01), except for agomphious upper second molar at 3.75mm. (3)The height of residual crest and width of sinus floor decreased remarkably with age and agomphious duration(P<0.01) while the width of sinus lateral walls didn't change so much with them(P>0.05). (4)Height of residual crest of the tooth extracted due to periodontitis was obviously lower than that of the tooth extracted due to residual root(crown) or crown fracture(P<0.01). CONCLUSIONS: The height and width of residual crest change significantly with age, agomphious duration and causes of tooth extraction. However, the width of lateral walls above sinus floor do not change so much with those factors. The internal wall of maxillary sinus floor is wider than the external wall at agomphious molar. This anatomic feature may be taken into consideration during implantation. The site and direction of implant can be adjusted equally according to the age, agomphious duration and causes of tooth extraction, so that maxillary sinus augmentation can be avoided in part of patients with low-set maxillary sinus.

[Prosthetic treatment of edentulous patient with hypohidrotic etcodermal dysplasia: report of one case].

PURPOSE: To explore the prosthetic treatment of edentulous patient with hypohidrotic etcodermal dysplasia, and observe the changes of esthetics, speech and masticatory function, and bilateral TMJ disc with MRI before and after treatment. METHODS: A complete denture with hypohidrotic etcodermal dysplasia of proband was made. And the changes of bilateral TMJ disc with MRI before and after prosthetic treatment were viewed. RESULTS: There was significant improvement in speech,masticatory function and facial esthetics,and anterior disc displacement was corrected normal. CONCLUSIONS: To prevent temporomandibular disorder (TMD) in edentulous patient with hypohidrotic ectodermal dysplasia, and improve facial esthetics, speech and masticatory function, early treatment is were necessary. Supported by Research Fund of Science and Technology Commission of Shanghai Municipality (Grant No. 08DZ2271100) and Shanghai Leading Academic Discipline Project (Grant No.T0202).

Computed tomography findings in radiation-induced osteosarcoma of the jaws.

OBJECTIVE: The objective of this study was to report the CT appearances of radiation-induced jaw osteosarcomas (RIJOS) following therapeutic irradiation. STUDY DESIGN: The CT studies of 7 subjects with RIJOS were reviewed retrospectively. RESULTS: RIJOS developed at 3 to 14 years following radiotherapy. Four patients had tumors in the maxilla and 3 in the mandible. Five tumors were osteoblastic, with 1 osteolytic and 1 mixed lesions. Osteoid tumor matrix mineralization was identified in 6 subjects. Periosteal reaction was demonstrated in 6 cases. All subjects showed a soft tissue extension component beyond the area of bone destruction. CONCLUSION: CT is a useful tool to identify RIJOS and plays an important role in preoperative assessment of the extent of the tumor.

[Imaging features and differentiated diagnosis of desmoplastic fibroma of the jaw bones].

PURPOSE: To investigate the imaging feature of desmoplastic fibroma (DF) of the jaw bones. METHODS: The records including diagnostic radiograph images of 8 patients were retrospectively analyzed. The age of the 8 patients ranged from 2 years to 70 years (means,28 years). The numbers of males and females were 3 and 5 respectively. Of 8 patients, 4 had local recurrence, which occurred 1 year after curettage. RESULTS: On conventional radiographs, the lesion was presented as a purely lytic tumor that did not contain any mineralized matrix. The zone of transition between tumor and normal bone was typically narrow and well defined but not sclerotic. Bone expansion in DF had an eccentric (n=3) and lace-like, reticular pattern (n=3). On CT scan, increased bone marrow density (n=3), a homogeneous soft-tissue density mass displaced adjacent muscle with lingual cortex eroded (n=3) were noted. On MRI, the lesion was displayed as large bony destruction area, with homogeneous hypointensity on T1-weighted images, non-homogenous hyperintensity on T2-weighted and did not enhance after Gd-DTPA administration. Images with Choline peek (Cho, at 3.2 ppm) was displayed at TE of 144 ms( PRESS, single voxel).Six mandibular cases and 2 maxillary tumors were located posteriorly. CONCLUSIONS: Recognition of DF is important because DF is more aggressive than other benign fibrous lesions, necessitating a wide surgical and careful long-term follow-up for local recurrence.