Impact of palatopharyngeal sizes changing on pharyngeal airflow fluctuation and airway vibration in a pediatric airway.

Snoring is common in children and is associated with many adverse consequences. One must study the relationships between pharyngeal morphology and snoring physics to understand snoring progression. Although some model studies have provided fluid-structure interaction dynamic descriptions for the correlation between airway size and snoring physics, the descriptions still need to be further investigated in patient-specific airway models. Fluid-structure interaction studies using patient-specific airway structures complement the above model studies. Based on reported cephalometric measurement methods, this study quantified and preset the size of the palatopharynx airway in a patient-specific airway and investigated how the palatopharynx size affects the pharyngeal airflow fluctuation, soft palate vibration, and glossopharynx vibration with the help of a verified FSI method. The results showed that the stenosis anterior airway of the soft palate increased airway resistance and airway resistance fluctuations, which can lead to increased sleep effort and frequent snoring. Widening of the anterior airway can reduce airflow resistance and avoid obstructing the anterior airway by the soft palate vibration. The pharyngeal airflow resistance, mouth inflow proportion, and soft palate apex displacement have components at the same frequencies in all airway models, and the glossopharynx vibration and instantaneous inflow rate have components at the same frequencies, too. The mechanism of this same frequency fluctuation phenomenon can be explained by the fluid-structure interaction dynamics of an ideal coupled model consisting of a flexible plate model and a collapsible tube model. The results of this study demonstrate the potential of FSI in studying snoring physics and clarify to some degree the mechanism of airway morphology affecting airway vibration physics.

Three-dimensional measurement and analysis of Mandibular Molar Distalization assisted by micro-implant anchorage combined with clear aligner.

Objective: To investigate the effect of micro-implant anchorage combined with a clear aligner on the efficiency of mandibular molar distalization and the protection of anterior teeth anchorage, provide reference for clinical scheme design. Methods: This is a prospective study. Seventeen patients who were treated in the Orthodontics Department of the Hospital of Stomatology affiliated to Fujian Medical University from 2019 to 2021 and used Invisalign clear aligners to move mandibular molars distally were included and divided into two groups according to anchorage types: Group-A and Group-B. Group-A (ten cases) were treated without micro-implant anchorage, while Group-B (seven cases) were treated with micro-implant anchorage nails for enhanced anchorage. The effect of micro-implant anchorage on crown and root distal movement of mandibular molars and the difference in three-dimensional movement between mandibular molars and mandibular central incisors were analyzed. Results: The crown distalization efficiency of mandibular first and second molars in Group-B was 68.66% and 71.02%, respectively, which were higher than those in Group-A(p<0.05). The mandibular central incisors in Group-A showed labial displacement and a small amount of elongation, while those in Group-B showed less anchorage loss(p<0.05). In Group-A, the crown was tilted in the distal direction and moved in the buccal direction during mandibular molar distalization(p<0.05). While in Group-B, the crown was tilted in the distal directio (p<0.05) and the mandibular second molar was depressed(p<0.05). Conclusion: In the process of mandibular molar distalization assisted by micro-implant anchorage combined with a clear aligner, better protects the anchorage of the mandibular central incisor and improves the efficiency of the molar crown distalization.

Quantitative assessment of cleft volume and evaluation of cleft's impact on adjacent anatomical structures using CBCT imaging.

OBJECTIVES: To determine pre-operative cleft volume and evaluate cleft´s impact on surrounding anatomical structures in children and adolescents with orofacial clefts using cone bean computed tomography (CBCT) imaging. METHODS: The present retrospective study retrieved CBCT examinations of 68 patients from a previous study. The examinations had been exposed either before (n = 53) or after (n = 15) alveolar bone grafting. Pre-operative volume of cleft was determined, and type and location were evaluated. Morphological changes on the adjacent anatomical structures, including the incisive foramen, the nasal septum and floor, and the inferior turbinate, were assessed. RESULTS: Mean bilateral cleft volume was 0.76 cm3, while mean unilateral cleft volume was 1.08 cm3; the difference was significant (p < 0.001). Variation in cleft volume, however, was large. The incisive foramen was not visible in the majority of cases with bilateral clefts (71%); the difference was significant (p = 0.001). In cases with unilateral clefts, the nasal septum in 87% was curved towards the cleft or graft side. Also, the mean size of the widest part of the inferior turbinate was 8.8 mm on the cleft or graft side and 10.4 mm on the non-cleft side. The difference was significant (p < 0.001). CONCLUSIONS: When required, CBCT is a feasible method for quantitatively illustrating alveolar clefts and their impact on the morphological development of surrounding structures. Variation in cleft volume was large.

Low-Dose Cone-Beam Computed Tomography for Assessment of Alveolar Clefts: A Randomized Controlled Trial in Image Quality.

BACKGROUND: Children born with an alveolar cleft receive bone grafts for improved function and aesthetics. The cleft area is examined radiologically before and after bone graft. Optimizing radiographic examination protocols is essential to protect these patients from possible delayed radiation injury later in life. This study investigates whether image quality of cone-beam computed tomography (CBCT) exposed with an ultra-low-dose (ULD) protocol is comparable to the clinical default protocol, the standard dose (SD) protocol, in visualizing details of importance in bone grafting of alveolar clefts. METHODS: In this randomized controlled study, 72 patients with unilateral or bilateral alveolar clefts between 9 and 19 years (mean age, 9.5 years) were randomized 1:1 with either a ULD or an SD CBCT examination protocol. The CBCT scans were conducted with a Planmeca ProMax Mid scanner with an 8 × 5-cm field of view. Two experienced radiologists blindly evaluated the images and visibility of cortical bone border, trabecular bone, tooth anatomy, root development, periodontal space, and cleft width. The visibility was categorized as unacceptable, acceptable, or excellent. RESULTS: Mann-Whitney U test showed no significant differences in structure visibility between ULD and SD protocols regarding anatomical structures of interest: cortical bone border ( P = 0.07), trabecular bone ( P = 0.64), tooth anatomy ( P = 0.09), root development ( P = 0.57), periodontal space ( P = 0.38), and cleft width ( P = 0.44). CONCLUSIONS: ULD and standard CBCT protocols provide comparable image quality in terms of structure visibility in the examination of alveolar clefts. The ULD protocol is preferred to the SD protocol because of the lower radiation dose without compromising diagnostic information of CBCT images. CLINICAL QUESTION/LEVEL OF EVIDENCE: Diagnostic, I.

Effects of periodontal initial therapy combined with orthodontic treatment on anterior tooth function and inflammatory factors in gingival crevicular fluid in patients with periodontal disease induced anterior tooth displacement.

Objective: To evaluate the effects of periodontal initial therapy combined with orthodontic treatment on anterior tooth function and inflammatory factors in gingival crevicular fluid in patients with periodontal disease induced anterior tooth displacement. Methods: This was a clinical comparative study. A total of 140 patients with anterior teeth displacement caused by periodontal disease in Fujian University of Traditional Chinese Medicine from May 2020 to May 2022 were selected and randomly divided into two groups. Patients in the control group received periodontal initial therapy, and those in the study group were provided with orthodontic treatment on the basis of initial therapy. Further comparative analysis was performed focusing on the clinical effects of the two groups, the changes of probing depth, anterior overjet degree, oral function and inflammatory factors in gingival crevicular fluid before and after treatment. Results: The efficacy of the study group was significantly higher than that of the control group(p=0.00). After treatment, the probing depth, the anterior overjet degree and the rate of bleeding on probing in the study group were significantly lower than those in the control group(P=0.00). Furthermore, the proportion of tooth mobility degrees I, II and III in the study group was significantly lower than that in the control group after treatment(P<0.05). The levels of post-treatment inflammatory factors in the study group were significantly lower than those in the control group(p=0.00). Conclusion: Periodontal initial therapy combined with orthodontic treatment has a significant effect on anterior teeth displacement caused by periodontal disease, which deserves promotion clinically.

Comparison of absorbed doses and organ doses measured with thermoluminescent dosimeters and Gafchromic film for cone beam computed tomography examination of the posterior mandibular region in a head phantom.

OBJECTIVES: We aimed to map the correlation between thermoluminescent dosimeters (TLDs) and Gafchromic film for measuring absorbed doses and to compare minimum, maximum, and mean absorbed doses over larger regions of interest and at various craniofacial organs and tissues during cone beam computed tomography (CBCT) exposure of the mandibular third molar region. STUDY DESIGN: We positioned TLDs at 75 measurement points in a head phantom. Gafchromic film was cut to the same shape as the 5 levels of the phantom and was placed on top of the TLDs. Both dosimetry methods thus included the surface of each level simultaneously. CBCT scans were made using a 5 × 5 cm field of view and a rotation angle of 200°. Measurements included absorbed dose distributions, doses at all 75 points, and minimum, maximum, and mean doses within organs and tissues. RESULTS: The correlation of point-dose measurements at all TLD sites with doses measured on film was strong (R2 = 0.9687), with greatest correlation at lower doses (<2 mGy). Large deviations between TLD and film measurements of minimum and maximum doses and absorbed doses to the organs occurred at all 5 levels. TLD positioning failed to cover several organ sites; for these, only absorbed dose measurements from the film were available. CONCLUSIONS: TLDs were unable to sample dose distributions and gradients accurately. The characteristics of Gafchromic LD-V1 film make it a favorable alternative in dental CBCT dosimetry.

Impact of sleep posture and breathing pattern on soft palate flutter and pharynx vibration in a pediatric airway using fluid-structure interaction.

Snoring is a common condition in the general population, and the management of snoring requires a better understanding of its mechanism through a fluid-structure interaction (FSI) perspective. Despite the recent popularity of numerical FSI techniques, outstanding challenges are accurately predicting airway deformation and its vibration during snoring due to complex airway morphology. In addition, there still needs to be more understanding of snoring inhibition when lying on the side, and the possible effect of airflow rates, as well as nose or mouth-nose breathing, on snoring remains to be investigated. In this study, an FSI method verified against in vitro models was introduced to predict upper airway deformation and vibration. The technique was applied to predict airway aerodynamics, soft palate flutter, and airway vibration in four sleep postures (supine, left/right lying, and sitting positions) and four breathing patterns (mouth-nose, nose, mouth, and unilateral nose breathing). It was found that, at given elastic properties of soft tissues, the evaluated flutter frequency of 19.8 Hz in inspiration was in good agreement with the reported frequency of snoring sound in literature. Reduction in flutter and vibrations due to the mouth-nose airflow proportion changes were also noticed when having side-lying and sitting positions. Breathing through the mouth results in larger airway deformation than breathing through the nose or mouth-nose. These results collectively demonstrate the potential of FSI for studying the physics of airway vibration and clarify to some degree the reason for snoring inhibition during sleep postures and breathing patterns.

Computational fluid-structure interaction analysis of flapping uvula on aerodynamics and pharyngeal vibration in a pediatric airway.

The uvula flapping is one of the most distinctive features of snoring and is critical in affecting airway aerodynamics and vibrations. This study aimed to elucidate the mechanism of pharyngeal vibration and pressure fluctuation due to uvula flapping employing fluid-structure interaction simulations. The followings are the methodology part: we constructed an anatomically accurate pediatric pharynx model and put attention on the oropharynx region where the greatest level of upper airway compliance was reported to occur. The uvula was assumed to be a rigid body with specific flapping frequencies to guarantee proper boundary conditions with as little complexity as possible. The airway tissue was considered to have a uniform thickness. It was found that the flapping frequency had a more significant effect on the airway vibration than the flapping amplitude, as the flapping uvula influenced the pharyngeal aerodynamics by altering the jet flow from the mouth. Breathing only through the mouth could amplify the effect of flapping uvula on aerodynamic changes and result in more significant oropharynx vibration.

Visibility of anatomical landmarks in the region of the mandibular third molar, a comparison between a low-dose and default protocol of CBCT.

OBJECTIVE: Optimization of radiographic examinations is essential for radiation protection. The objective of the study was to investigate the clinical applicability of a low-dose CBCT protocol as compared to the default for pre-surgical evaluation of mandibular third molars. MATERIAL & METHODS: Forty-eight patients (62 teeth) referred for pre-surgical mandibular third molar investigation were recruited after justification for CBCT. Two CBCT scans of each site were made using a default protocol and a low-dose protocol (Veraviewepocs 3D F40, J Morita Corp, Kyoto, Japan). The low-dose protocol had the same tube potential (90 kV) and exposure time (9.4 s) as the default, but with reduced tube current, from 5 mA to 2 mA. Four observers evaluated the visibility of five relevant anatomical variables. Image quality was ranked on a 3-point scale as diagnostically acceptable, doubtful, or unacceptable. The Wilcoxon signed-rank test compared differences between the two protocols. The significance level was set at p ≤ .05. RESULTS: No significant differences were found between the two protocols for any observer regarding the visibility of the relationship and proximity between the roots and the mandibular canal; root morphology; and possible root resorption of the second molar. The periodontal ligament differed significantly in visibility between the two protocols (p ≤ .05). CONCLUSIONS: This study indicates that a low-dose CBCT protocol with a 60% reduction of the tube current provides, in most cases, acceptable image quality for pre-surgical assessment of mandibular third molars. Optimization of CBCT protocols should be a priority according to recommended guidelines.

Cone beam computed tomography in the assessment of TMJ deformity in children with JIA: repeatability of a novel scoring system.

BACKGROUND: The temporomandibular joint (TMJ) is frequently involved in juvenile idiopathic arthritis (JIA). Diagnostic imaging is necessary to correctly diagnose and evaluate TMJ involvement, however, hitherto little has been published on the accuracy of the applied scoring systems and measurements. The present study aims to investigate the precision of 20 imaging features and five measurements based on cone beam computed tomography (CBCT). METHODS: Imaging and clinical data from 84 participants in the Norwegian study on juvenile idiopathic arthritis, the NorJIA study, were collected. Altogether 20 imaging features and five measurements were evaluated independently by three experienced radiologists for intra- and interobserver agreement. Agreement of categorical variables was assessed by Fleiss', Cohen's simple or weighted Kappa as appropriate. Agreement of continuous variables was assessed with 95% limits of agreement as advised by Bland and Altman. RESULTS: "Overall impression of TMJ deformity" showed almost perfect intraobserver agreement with a kappa coefficient of 0.81 (95% CI 0.69-0.92), and substantial interobserver agreement (Fleiss' kappa 0.70 (0.61-0.78)). Moreover, both "flattening" and "irregularities" of the eminence/fossa and condyle performed well, with intra- and interobserver agreements of 0.66-0.82 and 0.55-0.76, respectively. "Reduced condylar volume" and "continuity" of the fossa/eminence had moderate intra- and interobserver Kappa values, whereas continuity of the condyle had Kappa values above 0.55. Measurements of distances and angles had limits of agreement of more than 15% of the sample mean. CONCLUSIONS: We propose a CBCT-based scoring system of nine precise imaging features suggestive of TMJ deformity in JIA. Their clinical validity must be tested.

Dental plaque and gingival bleeding in adolescents with juvenile idiopathic arthritis and controls: a multilevel analysis.

OBJECTIVE: To explore whether plaque and gingival bleeding are more frequently experienced by adolescents with juvenile idiopathic arthritis (JIA) compared to matched controls without JIA; explore whether surface- and site-specific periodontal outcomes vary between the two groups; and for participants with JIA, investigate associations between disease-specific features and periodontal outcomes. MATERIAL AND METHODS: In this comparative cross-sectional study, selected surfaces, and sites of index teeth in 10-16-year-olds with JIA and matched controls were examined by modified versions of Simplified Oral Hygiene Index (OHI-S) and Gingival Bleeding Index (GBI). Mixed-effects logistic regressions, reporting odds ratios (OR) with 95% confidence interval (CI), were applied. Intra-class correlation coefficients (ICCs) were calculated to quantify the degree of dependency of measures within the same individual. RESULTS: 144 and 159 adolescents with JIA were evaluated according to OHI-S and GBI; corresponding numbers of controls were 154 and 161. Plaque and gingival bleeding were more frequent in individuals with JIA than controls. Adjusted analyses showed association between JIA status and OHI-S > 0 (OR = 2.33, 95% CI: 1.47 - 3.67, ICC = 0.45) and GBI > 0 (OR = 1.54, 95% CI: 1.10 - 2.16, ICC = 0.41 and 0.30). Surface-specific distribution of plaque varied among the two groups. CONCLUSIONS: Our results highlight the importance of increased awareness of oral health care in patients with JIA and that surface- and site-specific differences in periodontal outcomes exist between individuals with JIA and controls. Few JIA disease-specific variables associated with plaque or gingival bleeding.

Cone beam computed tomography indications for interdisciplinary therapy planning of impacted canines.

OBJECTIVE: To investigate how cone beam computed tomography (CBCT) affects the therapeutic planning of impacted maxillary canines. STUDY DESIGN: A total of 132 impacted canines from 89 pediatric patients were collected from 3 specialist clinics in Stockholm, Sweden. An interdisciplinary therapy planning team consisting of 5 dental specialists evaluated each case and chose their preferred treatment alternative, initially without and later with CBCT images, to decide whether CBCT was justified for therapy planning. Predefined variables measurable using only 2-dimensional (2D) assessments were analyzed using stepwise logistic regression analyses. RESULTS: The CBCT was considered indicated in 47% of the cases. Additional information from CBCT led to a treatment decision change in 9.8%. Significant 2D predictors for CBCT justification were horizontal canine angulation compared with vertical angulation (odds ratio [OR] = 10.9), extraction strategy involvement (OR = 6.7), and buccally positioned canines compared with palatal (OR = 5.3), central (OR = 25.0), and distal or uncertain positions (OR = 7.7). CONCLUSIONS: The benefit-risk assessment of CBCT for impacted canines may be reinforced by performing and applying justification decisions for CBCT acquisition at the therapeutic thinking level. If preliminary treatment planning motivates further in-depth investigation of either root status or tooth location, a CBCT is indicated.

Do preterm-born children and adolescents have greater need for dental care as compared to full term-born controls?

BACKGROUND: Preterm birth has been shown to cause various long-term health issues. Children who were born preterm have also been observed to have more dental behaviour management problems (DBMP) during dental examinations and treatment than children born full term. It is known that dental radiographic examinations can be uncomfortable and cause anxiety in paediatric patients. Thus, our aims were to retrospectively compare dental care related examinations and treatments carried out in three different age intervals (3-6 years, 7-12 years, and 13-19 years) among preterm- and full-term born children and adolescents. METHODS: The present study included 311 patient files: 122 very preterm-born and 33 extremely preterm-born children and adolescents (< 32 gestational weeks). A matched control group of 156 full term-born children and adolescents (≥ 37 gestational weeks) was analysed for comparison. Various factors, including DBMP, missed appointments, dental caries, and radiographic examinations, were retrieved from the dental records for three age intervals: 3-6 years, 7-12 years, and 13-19 years. RESULTS: Extremely preterm-born children missed significantly more dental appointments and presented with more DBMP during dental examinations and treatment than full term-born children in the 3-6-year age group; the same was observed for the very preterm-born in the 7-12-year age group. No significant differences in DBMP during bitewing and periapical examinations or in number of bitewing, periapical and panoramic radiographs occurred between the groups in any age interval. CONCLUSION: Preterm-born children and adolescents may need more flexibility in booking and receive reminders for scheduled visits with the general dental team. Due to the non-significant differences in dental care related oral examinations and treatments, the same dental care service may be applied to the preterm- and full-term born children and adolescents.

Clinical efficacy of highly agglutinative staphylococcin combined with neoadjuvant chemotherapy on patients with intermediate or advanced oral cancer.

Objectives: To evaluate the clinical efficacy of highly agglutinative staphylococcin combined with neoadjuvant chemotherapy on patients with intermediate or advanced oral cancer. Methods: A total of 80 patients with intermediate or advanced oral cancer treated in Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine from January 2020 to January 2022 were included. Patients were divided into two groups based on their treatment choice, with 40 cases in each group. Patients in the control group were given paclitaxel combined with cisplatin chemotherapy regimen: paclitaxel 150 mg/m2 and cisplatin 100 mg/m2 on Day-1, with 28 days as one cycle of chemotherapy for a total of three cycles. Patients in the experimental group received intramuscular injection of 500U highly agglutinative staphylococcin once a day for two weeks on the basis of chemotherapy, and continued the next course of treatment after 1 week of withdrawal, with a total of two courses. After treatment, the therapeutic effect, adverse drug reactions, changes in tumor markers such as CEA, NSE, CA19-9 and CA125 before and after treatment, as well as differences in levels of CD3+, CD4+, CD8+ and CD4+/CD8+ of T lymphocyte subsets between the two groups before and after treatment were compared and analyzed. Results: The total efficacy of the experimental group was 80%, which was significantly better than 57.5% of the control group (P=0.03). The incidence of adverse drug reactions in the experimental group was 17.5%, while that in the control group was 42.5%, showing a statistically significant difference (P=0.02), and the WBC count decreased more significantly in the control group (P=0.04). CEA, NSE, CA19-9 and CA125 decreased significantly in the experimental group after treatment compared with the control group, with a statistically significant difference (P=0.00). Moreover, the levels of CD3+, CD4+, CD4+/CD8+ in the experimental group after treatment were significantly higher than those in the control group, with statistically significant differences (CD3+, P=0.03; CD4+, P=0.00; CD4+/CD8+, P=0.00), while CD8+ did not change significantly (P=0.95). Conclusions: Highly agglutinative staphylococcin combined with chemotherapy is a safe and effective treatment regimen with definite curative effect for patients with intermediate or advanced oral cancer. With such a regimen, tumor markers are remarkably reduced, immune function can be significantly improved, and adverse reactions will be evidently reduced.

Oral health-related quality of life in 4-16-year-olds with and without juvenile idiopathic arthritis.

BACKGROUND: Few studies have investigated oral health-related quality of life (OHRQoL) in young individuals with juvenile idiopathic arthritis (JIA). Aims were to investigate whether OHRQoL differs between children and adolescents with JIA compared to controls without JIA, while adjusting for socio-demographic-, behavioral- and oral health-related covariates. Furthermore, to explore whether socio-behavioral and oral health-related covariates of OHRQoL vary according to group affiliation and finally, specifically for individuals with JIA, to investigate whether disease-specific features associate with OHRQoL. We hypothesized that participants with JIA have poorer OHRQoL compared to participants without JIA. METHODS: In this comparative cross-sectional study participants with JIA (n = 224) were matched to controls without JIA (n = 224). OHRQoL was assessed according to Early Childhood Oral Health Impact Scale (ECOHIS) (4-11-years-olds) and the child version of Oral Impacts on Daily Performances (Child-OIDP) (12-16-years-olds). JIA-specific characteristics were assessed by pediatric rheumatologists and socio-demographic, behavioral and self-reported oral health information collected by questionnaires. Index teeth were examined for caries by calibrated dentists. Multiple variable analyses were performed using logistic regression, reporting odds ratio (OR) and 95% confidence interval (CI). Two-way interactions were tested between group affiliation and the socio-behavioral- and oral health-related variables on the respective outcome variables. RESULTS: In total, 96 participants with JIA and 98 controls were evaluated according to ECOHIS, corresponding numbers for Child-OIDP was 125 and 124. Group affiliation was not associated with impaired ECOHIS or Child-OIDP in adjusted analyses (OR = 1.95, 95% CI 0.94-4.04 and OR = 0.99, 95% CI 0.46-2.17, respectively). Female adolescents with JIA were more likely than males to report oral impacts according to Child-OIDP. Continued activity or flare was found to adversely affect Child-OIDP, also self-reported outcome measures in JIA associated with Child-OIDP. CONCLUSIONS: This study did not provide consistent evidence to confirm the hypothesis that children and adolescents with JIA are more likely to have impaired OHRQoL compared to their peers without JIA. However, female adolescents with JIA were more likely than males to report impacts on OHRQoL. Furthermore, within the JIA group, adolescents with continued disease activity, flare or reporting pain, physical disability, had higher risk than their counterparts of impaired OHRQoL.

Pre-surgical radiographic and clinical features as predictors for temporomandibular joint discectomy prognosis.

OBJECTIVES: This study aimed to identify potential clinical and radiological predictors associated with the outcome of discectomies. METHODS: In this retrospective observational study, the material comprised preoperative CBCT images and medical records of 62 patients with disc derangement disorders, who had undergone discectomy because of disc displacement with reduction (DDwR), disc displacement without reduction (DDwoR), systemic arthritis (SA), or joint hypermobility. Clinical and radiographic variables were analysed in relation to success rate determined by subjective, objective and combined outcomes. RESULTS: The success odds ratio was 11 times higher in patients with painful DDwR versus that of SA (p = 0.03), and even 25.9 times higher when considering solely objective outcome (p = 0.03). In the absence of subchondral pseudocyst, there were 5.2 times higher odds to have a successful subjective outcome (p = 0.04). Extensive bone apposition on the temporal joint component indicated a 9.3 times higher likelihood of a failed objective outcome (p = 0.04). CONCLUSIONS: There is a significant higher risk for combined outcome failure for the diagnosis SA involving the TMJ compared with DDwR. Predictors of importance based on CBCT findings related to the objective outcome failure were extensive bone apposition on the temporal joint component and condylar subchondral pseudocysts for the subjective outcome failure.

Radiographic imaging in relation to the mandibular third molar: a survey among oral surgeons in Sweden.

OBJECTIVES: To query the experience of oral surgeons concerning referral routines and preferences for radiographic imaging modality before surgical removal of mandibular third molars and investigate factors that influence imaging modality preferences. MATERIALS AND METHODS: Members of the Swedish Association of Oral and Maxillofacial Surgeons (n = 280) were invited to participate in a web-based digital survey concerning their experiences and use of three imaging modalities in pre-surgical assessment of mandibular third molar removal. The survey comprised multiple-choice questions and four cases depicted in images; respondents reported whether they would supplement the cases with other images and, if so, from which modality. RESULTS: The response rate was 64%. Panoramic radiographs were most commonly used in pre-surgical planning (response options: always or often), significant difference between professions (p = 0.039), and considered to facilitate treatment planning (87%), as was CBCT (82%); for 51%, CBCT reduced post-operative complications. Preferred modality for localizing the mandibular canal was fairly evenly distributed and for non-complex case, significant difference between subgroups of OMFS surgeons was found (p = 0.003) as to preference for intraoral radiographs. CONCLUSIONS: A majority of respondents received a report within 2 weeks of their referral for CBCT and would read the report and view the images before surgery. Image modality preference differed depending on case complexity, with a greater perceived need for CBCT. Profession and practical experience affected choice. CLINICAL RELEVANCE: Choice of imaging modality in mandibular third molar assessment is also important from dose delivery and social economy standpoints.

Radiographic features in 2D imaging as predictors for justified CBCT examinations of canine-induced root resorption.

OBJECTIVES: This retrospective observational study aimed to evaluate the diagnostic accuracy of two-dimensional radiographs on canine-induced root resorption (CIRR) in lateral incisors and identify predictors of CIRR in patients with impacted maxillary canines (IMC). METHODS: Ninety-nine patients aged 9-17 years, with 156 IMCs, were included in the study. All had CBCT-volumes and two-dimensional radiographs consisting of at least one panoramic radiograph. Two radiologists jointly viewed all cases twice. First, radiographic features related to the IMC and possible CIRR were recorded from two-dimensional radiographs. Then, CIRR was determined from CBCT and according to position and extension classified as mild, moderate and severe. RESULTS: CIRRs was detected in 80% of lateral incisors (mild: 45%; moderate: 44%; severe: 11%). The sensitivity was generally low at mild and moderate cut-offs (29 and 29%), and somewhat higher for severe (50%). Corresponding specificities were 48%, 63% and 68%. Canine cusp-tip superimposing the lateral incisor's middle third and root/crown ratio >1 was positively associated with mild CIRR, with an odds ratio (OR) of 3.8 and 6.7, respectively. In addition, the root development stage was positively associated with moderate/severe CIRR when the canine root was nearly or fully developed (OR = 3.1). CONCLUSIONS: The diagnostic accuracy of two-dimensional radiographs was inadequate for detecting CIRR amongst patients referred for CBCT examinations. Based on our results, none of the suggested two-dimensional radiographic features could predict moderate/severe CIRR except for root development stage. IMC in a later stage of root development seems to be associated with a higher risk of moderate/severe CIRR.

Image quality assessment of low-dose protocols in cone beam computed tomography of the anterior maxilla.

OBJECTIVES: To evaluate overall image quality and visibility of anatomic structures on low-dose cone beam computed tomography (CBCT) scans and the effect of a noise reduction filter for assessment of the anterior maxilla. METHODS: We obtained 48 CBCT volumes on 8 skull-phantoms using 6 protocols: 2 clinical default protocols [standard definition (SD) and high definition (HD)] and 4 low-dose protocols, 2 with a noise reduction filter [ultra-low-dose with high definition (ULDHD) and ultra-low-dose (ULD)] and 2 without [low-dose with high definition (LDHD) and low-dose (LD)]. Overall image quality and visibility of 8 anatomic structures were assessed by 5 observers and statistically analyzed using the Wilcoxon signed rank test. Intra- and interobserver agreement was measured using Cohen's weighted kappa. RESULTS: HD provided higher overall image quality than diagnostically required; LD scored lower than diagnostically acceptable. ULDHD, ULD, and LDHD were acceptable. For anatomic structures, ULDHD and ULD were acceptable. LDHD and LD showed significantly inferior visibility for 1 and 4 structures, respectively. Mean values of intra- and interobserver agreement were 0.395 to 0.547 and 0.350 to 0.370, respectively. CONCLUSIONS: ULDHD, ULD, and LDHD may be recommended for assessment of impacted maxillary canines. The noise reduction filter affects image quality positively only at low exposure.

Anxiety of hearing impaired students in special schools during COVID-19 / 中国学校卫生

Objective@#To understand anxiety status among students with hearing loss under the epidemic of novel coronarirus pneumonia, and to provide evidence for promoting mental health of hearing impaired students.@*Methods@#On March 10, 2020, 612 hearing impaired students in special schools in 6 provinces,including Guizhou,Sichuan,Hunan,Zhejiang,Chongqing and Xinjiang were investigated online with anxiety scale.@*Results@#The detection rate of anxiety in hearing impaired students was 52.8%. There was significant difference in the detection rate of anxiety among hearing impaired students by different economic status(from very good,good,mederate,poor and very poor:54.1%,63.9%,51.4%,40.7% and 38.8%) and relationship with their parents(from very good,good,mederate,poor and very poor:45.1%,55.7%,60.0%,84.6%,87.5%) ( χ 2=16.59, 62.46, P <0.05).@*Conclusion@#The anxiety level of hearing impaired students was high under the epidemic of novel coronavirus pneumonia. Hearing impaired students from families with good economic conditions and poor parent child relations are prone to anxiety. It is particularly important to establish a good parent child relationship.