Disc Position Research Articles

Effectiveness of Occlusal Splint Therapy in Moderating Temporomandibular Joint Disorders With Joint Displacement: A Retrospective Analysis Using Cone Beam Computed Tomography.

Background Temporomandibular joint disorders (TMD) represent a prevalent group of conditions impacting the temporomandibular joint. Among the therapeutic interventions, occlusal splint therapy has gained recognition for its potential to address TMD symptoms, particularly in cases involving joint displacement. Objective This study aims to investigate the effectiveness of occlusal splint therapy in cases of moderate TMD with joint displacement, focusing on changes in condylar position, joint morphology, and patient-reported outcomes. Methods A retrospective analysis was conducted involving 148 participants who underwent occlusal splint therapy between January 2018 and December 2020. Data were collected through cone beam computed tomography (CBCT) imaging for precise assessments of condylar position and joint morphology. Ethical approval was obtained, and participants provided informed consent. Baseline characteristics, medical history, and TMD severity were recorded. Occlusal splint therapy included individualized fabrication, occlusal analysis, adjustments for optimal fit, and prescribed wear schedules. Follow-up included CBCT scans at specified intervals (three months and six months), with participant-reported outcomes collected. The data analysis was conducted using IBM SPSS Statistics for Windows, Version 22.0 (Released 2013; IBM Corp., Armonk, NY, USA). Paired t-tests or nonparametric equivalents were employed to assess changes in condylar position and joint morphology. Subgroup analyses were conducted to explore potential factors influencing treatment outcomes. The significance level was set at p < 0.05 for all statistical tests. Results The entire cohort (n = 148) had a mean age of 32.5 years (± 8.1), with a balanced gender distribution. Changes in condylar position revealed a statistically significant improvement (p = 0.03), with a mean decrease of 0.2 mm posttreatment. Joint morphology changes indicated increased joint space width (p = 0.01), improved disc position (p = 0.02), and nonsignificant alterations in bony structures (p = 0.10). Patient-reported outcomes demonstrated significant improvements in pain levels, jaw functionality, and satisfaction (all p < 0.001). Age and gender subgroup analyses showed consistent improvements in condylar position, joint morphology, and patient-reported outcomes across different groups. Conclusion Occlusal splint therapy demonstrated effectiveness in improving condylar position, joint morphology, and patient-reported outcomes in cases of moderate TMD with joint displacement. The findings underscore the potential of occlusal splint therapy as a viable intervention for managing TMD, providing valuable insights for clinicians and researchers.

МАГНИТНО-РЕЗОНАНСНАЯ ТОМОГРАФИЯ ВИСОЧНО-НИЖНЕЧЕЛЮСТНОГО СУСТАВА ПРИ ДИАГНОСТИКЕ ПАРАФУНКЦИЙ ЗУБОЧЕЛЮСТНОЙ СИСТЕМЫ С ПОМОЩЬЮ ЦИФРОВОГО АППАРАТА T-SCAN

Parafunctions of the dental system occupy a special position among dental diseases, due to the complexity of their diagnosis, treatment, complex and varied clinical picture. Methods for screening and monitoring patients with parafunctions remain an urgent scientific and practical task. Most often, this manifests itself unconsciously in the form of daytime or nighttime bruxism or clenching. Parafunction is one of the etiological factors of pain dysfunction of the temporomandibular joint. In the diagnosis of structural changes in the temporomandibular joint, the “gold” standard is magnetic resonance imaging. Due to the high contrast of soft tissues, magnetic resonance imaging is a method for diagnosing structural changes in the tissues of the temporomandibular joint and allows the most accurate, highly informative and quick assessment of the condition and function of intra- and extra-articular elements. In daily practice, dentists need simple and practical methods for diagnosing and parafunctional activity. Digital dentistry provides opportunities for assessing occlusal contacts. T-scan is one of the most functional digital devices. The purpose of the study was to increase the efficiency of providing dental care to patients with parafunctions by identifying the severity of bruxism and clenching using the T-scan apparatus and magnetic resonance imaging. The study involved functional analysis using a digital T-scan device and magnetic resonance imaging. The results of the study, in patients with parafunctions, the average areas of wear facets were identified for each degree of severity for each side of the dentition. The values of occlusal parameters of the left side in patients in the group with bruxism and clenching prevail over the values of the right side of the dentition. With mild severity, there was a normal position of the articular disc and a small ventral displacement with reposition according to the Wilkes classification of internal disorders of the temporomandibular joint. With moderate severity, a small ventral displacement with and without reposition was noted. In severe cases, there was a small ventral displacement without reposition, a complete ventral displacement of the articular disc with and without reposition. Thus, it has been proven that diagnostics using digital analysis, assessing the severity of parafunctional activity and magnetic resonance data selects the necessary tactics for the treatment and prevention of dysfunctional conditions of the dental system. This technique allows for screening and monitoring of patients with bruxism and clenching.

Comparative study of clinical and MRI features of TMD patients with or without joint effusion: a retrospective study

BackgroundThe relationship between joint effusion and temporomandibular disorders (TMD) remains unclear. The purpose of this study was to investigate the correlation among joint effusion, clinical features and MRI imaging features of TMD.MethodsA total of 1532 temporomandibular joints (TMJs) from 766 patients (605 females and 161 males) with the mean age of 31.68 ± 13.71 years from January 2022 to June 2023 were included in the study. Clinical and MRI features were collected and analyzed. Chi-Square test, Spearman correlation coefficient and binary logistic regression analysis were performed.ResultsPatients with joint effusion were significantly older and had smaller value of MIO (p < 0.001). There were significant differences in the distribution of joint sounds (with or without), joint pain (with or without), disc morphology (biconcave, contracture, irregular and lengthened) and disc position between joint effusion group (JE) and non-joint effusion group (NA) (P < 0.05).The odds of having joint effusion were 1.726 higher in patients with joint sounds when compared to those without joint sounds. The odds of having joint effusion were 8.463 higher in patients with joint pain when compared to those without joint pain. The odds of having joint effusion were 2.277 higher in patients with contracture when compared to those with biconcave. The odds of having joint effusion were 1.740 higher in patients with anterior disc displacement with reduction (ADDWR) when compared to those with normal disc position. The prediction accuracy of this model is 74.9%, and the area under curve (AUC) is 79.5%, indicating that it can be used for the prediction and the judgment effect is average.ConclusionsThe results demonstrated that joint sounds, joint pain, contracture, and ADDWR are high risk factors for joint effusion, especially joint pain.Trial registrationThis study was retrospectively registered on 28/03/2022 and endorsed by the Ethics Committee of Affiliated Stomatology Hospital of Guangzhou Medical University (LCYJ2022014).

Temporomandibular joint disc position and shape in patients submitted to two protocols of rapid maxillary expansion and face mask therapy: A randomized clinical trial.

The objective of this prospective study was to assess possible changes in the position and shape of the temporomandibular joint (TMJ) articular disc in patients treated with two protocols of rapid maxillary expansion (RME) and face mask (FM) therapy. A sample of 88 patients with Class III or Class III subdivision malocclusions, aged between 6 and 13 years, were consecutively selected and divided into three groups (G): G1-34 patients were treated with RME, followed by FM therapy; G2-34 patients were treated using RME according to modified alternate rapid maxillary expansion and constriction (ALT-RAMEC) protocol, followed by FM therapy. These treated groups were randomly (1:1 allocation ratio) distributed according to the two treatment protocols. G3 - Control Group - 20 untreated patients were followed. Magnetic resonance imaging (MRI) TMJs were obtained before (T1) and after (T2) a treatment period or follow-up. McNemar test, Fisher's exact test and intra- and inter-observer concordance (K) were performed (p ≤ .05). There were no statistically significant differences in the baseline cephalometric variables at T1 between the groups. There were statistically significant differences between the groups (p < .001) in relation to the disc shape in T1, since G1 (8 TMJs -11.76%) presented higher occurrences of altered forms in comparison with G2 (no changes). No significant differences were observed in disc position CM and OM (G1 - p > .999; G2 - p = .063; G3 - p = .500) and shape (G1 - p > 0.999; G2 - p = .250; G3 - not calculable), between T1 × T2, in any of the groups studied. The two treatment protocols did not have adverse effects on the position and shape of the TMJ disc, in a short-term evaluation.

Clinical and MRI-Based Assessment of Patients with Temporomandibular Disorders Treated by Controlled Mandibular Repositioning.

Occlusal splints and anterior repositioning splints (ARSs) are widely accepted treatments for temporomandibular disorders (TMDs). However, there is uncertainty with regard to the most suitable amount of mandibular repositioning. The aim of this study is to evaluate the clinical and functional effects of the therapeutic position (ThP) established based on the Controlled Mandibular Repositioning (CMR) method. In this clinical trial, 20 subjects with 37 joints with disc displacement with reduction were recruited. The initial standard functional diagnostic protocol, MRI, and digital condylography were performed, and ThP was calculated with the CMR method. After a 6-month follow-up, the standard diagnostic protocol was repeated. The change in disc position was evaluated by means of MRI after 6 months of CMR therapy. The MRI findings in the parasagittal plane demonstrated that out of the 37 joints presenting disc displacement, 36 discs were successfully repositioned; thus, the condyle-disc-fossa relationship was re-established. Therefore, the success rate of this pilot study was 97.3%. The mean position of the displaced discs was at 10:30 o'clock of the TMJ joint and at 12:00 o'clock after CMR therapy. The ThP determined using the CMR approach reduced all of the anteriorly displaced discs (except one). The CMR method allowed to define an optimum ThP of the mandible thus supporting patients' effective adaptation to treatment position.

Relationships between functional temporomandibular joint space and disc morphology, position, and condylar osseous condition in patients with temporomandibular disorder.

To investigate the correlations between joint space and temporomandibular joint (TMJ) components and the compressive states of the disc and condyle subsequent to joint space changes. A total of 240 TMJs were categorized according to disc morphology, disc position, and condylar osseous condition. The two-dimensional (2D) and three-dimensional (3D) measurements were compared. The functional joint space (FJS) and disc areas on closed- and open-mouth images (DA-C and DA-O) were also calculated, and the joint space was measured in five directions. Different groups of TMJ components were compared. A spring model was used to simulate the effect of condylar displacement on the disc and condyle. Disc morphology was strongly correlated with its position. The measurements were equivalent between 2D and 3D methods. DA-C and FJS differed significantly between groups. The DA-C to FJS ratio differed between the Class 2 and Class 3 groups and between disc displacement groups with and without reduction. Altered disc morphology and position were correlated with significant changes in joint space in the 60°, 90°, and 120° directions. Despite minor discrepancies among condylar osseous conditions, reduced joint space was correlated with bone destruction at the corresponding site. The spring model stimulation revealed that condylar displacement caused elevated stresses on the disc and condyle. Condylar displacement causes joint space alterations while exerting compressive pressure on both the disc and condyle. Proper condylar positioning within the fossa is recommended to ensure sufficient articular disc accommodation.

Association Between Articular Eminence Structure and Joint Spaces in Temporomandibular Joints with Anterior Disc Displacement.

The association among the joint spaces, articular eminence morphology, and disc displacement is not well documented in the literature. This study aims to evaluate and compare the joint spaces and the articular eminence structure (eminence height [Eh] and inclination [Ei]) using cone-beam computed tomography (CBCT) of temporomandibular joints (TMJs) with anterior disc displacements and joints with normal disc position. The study groups consisted of 75 TMJs of 39 patients. The disc status of TMJs was diagnosed with magnetic resonance imaging, and the measurements were performed on CBCT. Three groups, that is, normal disc position (NDP) group, anterior disc displacement with reduction (ADDWR) group, and anterior disc displacement without reduction (ADDWoR) group, were established. Anterior, superior, posterior joint spaces (AJS, SJS, and PJS, respectively), articular Eh, and articular Ei were measured. Statistical Package for the Social Sciences version 22 was used for statistical analysis. Shapiro-Wilk test was used to check the normality of data. Intergroup comparisons of categorical variables were assessed with Fisher-Freeman-Halton test. For comparison of continuous variables parameters, Mann-Whitney U test and Kruskal-Wallis test were used. Statistical significance level was determined as P < 0.05. Significant differences were not found in intergroup comparisons for PJS. However, the difference between groups was found to be significant for AJS, SJS, Eh, and Ei. Intergroup comparisons were performed for these parameters. No significant difference was found between the NDP group and the ADDWR group for AJS, SJS, Eh, and Eİ. The mean AJS, SJS, Eh, and Ei values in ADDWoR were found to be significantly lower compared to the corresponding values in both NDP and ADDWR groups. Decreased AJS and SJS when TMJ is evaluated with CBCT may be an indicator of ADDWoR. Authors suggest that narrowed articular Ei and reduced articular Eh can be one of the predisposing factors for anterior disc displacement.

Arthroscopic reduction and rigid fixation of the anteriorly displaced temporomandibular joint disc without reduction using titanium screw: a case series.

To evaluate the effectiveness of arthroscopic reduction and rigid fixation (ARRF) using a suture-free titanium screw as a treatment approach to temporomandibular joint's (TMJ) anterior disc displacement without reduction (ADDwoR) and assess its impact on clinical outcomes, including improvements in symptoms related to TMJ disorders. A series of twenty patients presented to the Department of Orthognathic and Temporomandibular Surgery at West China Hospital of Stomatology between September 2022 and January 2023, complaining of symptoms such as pain, clicking, and limited mouth opening. Standard magnetic resonance image (MRI) imaging T1 and T2 sequences in both sagittal and coronal views study with closed and maximal open mouth positions were taken preoperatively to assess the disc's position, integrity, and shape. Also, cone-beam computed tomography (CBCT) scans images to find any degenerative changes and evaluate the condylar bone's features and volume. Additionally, the clinical examination assesses limited oral opening, mechanical pain, and the presence of any noises such as clicking and crepitus. All cases were treated under general anesthesia using the arthroscopic release, reduction, and rigid fixation of the TMJ's ADDwoR to establish a normal disc-condyle relationship and to restore the functional position. Patients' symptoms, such as pain and mouth opening, improved significantly following the arthroscopic treatment. Postoperative MRI and CBCT imaging follow-up conducted at 6 months demonstrated the stable position of the reduced TMJ disc and the fixation screw. Notably, none of the patients exhibited signs of relapse during this follow-up period. Overall, the ARRF of TMJ's ADDwoR using a suture-free titanium screw proved to be safe and provides satisfactory results, in addition to the several advantages of using suture-free titanium screws, such as biocompatibility, strong fixation, and durability. However, it is a technically demanding procedure requiring extensive, long-term training. ARRF using a cost-effective fixation titanium screw to treat ADDwoR emerges as a clinically effective minimally invasive approach.

Peeler core and slabwood fibre properties for Pinus radiata D.Don pulp production

Background: Pulp production based on Pinus radiata D.Don is constantly improving the value recovery of logs. One example is using the peeler cores and slabwood derived from sawing and peeling processes to produce pulp. However, these two raw materials have not been characterised for their fibre properties. Methods: We report on four wood fibre quality attributes derived from peeler cores and slabwood, directly influencing pulp quality and pulping process: fibre length (mm), fibre width (µm), fines content (%), and coarseness (µg/m). This pilot study sampled two P. radiata stands grown on different sites and early silvicultural regimes in the Araucanía Region of Chile. Analysis of wood fibre consisted of three trees per stand, and six discs per tree: two at the bottom, two at breast height (1.3 m), and the last two at 5.23 m height. Results: The trajectory of mean annual increment in diameter at breast height (MAI) and periodic annual increment in diameter at breast height (PAI) for trees in the two stands aligned with their respective site qualities and silvicultural regimes. In Stand 1, with a site index of 36, and Stand 2, with a site index of 31, the average proportions of juvenile wood (measured at 1.3 m) were 50% and 53%, respectively. Thus, despite weed control and fertiliser application in Stand 1, there was no increase observed in the proportion of juvenile wood. There were significant differences in fibre properties between peeler core and slabwood, and these differences were present across the range of tree heights and diameters (p&lt;0.05). While there were no statistically significant differences among disc positions, significant distinctions emerged between stands and wood types. The interaction between these factors was also found to be statistically significant (p&lt;0.05). Conclusions: Our study suggests that adding these two materials into the mix for producing pulp would have positive implications due to pulp from peeler core is more suitable for printing and writing grades and addition of mature wood from slabwood, could improve strength properties of paper manufacture. However, it is necessary to test the optimal proportion for the final mix.

A three-dimensional imaging study of the effect of anterior disc displacement on the bony structural relationship of the temporomandibular joint

Objective: To investigate the correlation between the osseous structure of temporomandibular joint (TMJ) and three different status of anterior disc location, so that it could guide the clinical diagnosis further. Methods: Fifty-two patients [46 females and 6 males, with an age of (27.8±8.3) years] who treated with MRI and cone beam CT, were recruited from the Temporomandibular Joint Specialist Clinic, The First Affiliated Hospital of Xinjiang Medical University, between March 2018 to December 2021. According to the radiographic findings of the level of anterior disc displacement (ADD) in TMJ, patients were divided into three groups: normal articular disc position (NADP, n=28 TMJs), anterior disc displacement with reduction (ADDWR, n=28 TMJs), and anterior disc displacement without reduction (ADDWoR, n=28 TMJs). In the light of the reconstructed three-dimensional model, ten representative morphological parameters including condylar volume (CV), condylar superficial area (CSA), fossa volume (FV), fossa superficial area (FSA), the proportion of the condylar volume in the articular fossa (CV%), the proportion of the condylar superficial area in the articular fossa (CSA%), superior joint space (SJS), anterior joint space (AJS), posterior joint space (PJS), and medial joint space (MJS), were measured respectively under one-way analysis of variance (ANOVA), Kruskal-Wallis Htest and receiver operator characteristic curve(ROC curve) analyses. Results: CV and CSA values varied significantly in the pathological progression from normal location to irreversible anterior displacement in TMJ. For CV value, NADP group [(1 834.90±667.67) mm3]>ADDWR group [(1 747.34±369.42) mm3]>ADDWoR group [(1 256.29±418.27) mm3] [t=4.31, P(NADP-ADDWoR)<0.001; t=3.66, P(ADDWR-ADDWoR)<0.001], for CSA value, NADP group [(859.27±216.01) mm2]>ADDWR group [(838.23±118.82) mm2]>ADDWoR group [(669.14±150.26) mm2] [t=4.27, P(NADP-ADDWoR)<0.001; t=3.80, P(ADDWR-ADDWoR)<0.001]. The difference of SJS value in NADP group [(2.22±0.88) mm], ADDWR group [(1.94±0.64) mm] and ADDWoR group [(1.45±0.57) mm], was statistically significant [t=4.11, P(NADP-ADDWoR)<0.001; t=2.63, P(ADDWR-ADDWoR)=0.010]. The results of MJS in NADP group [(5.03±1.41) mm], ADDWR group [(3.86±1.32) mm], and ADDWoR group [(4.91±1.65) mm] were significantly different [t=3.00, P(NADP-ADDWR)=0.004; t=2.63, P(ADDWR-ADDWoR)=0.009]. As calculated by the ROC curve analysis, CV, CSA and SJS showed that (AUCCV=0.77, AUCCSA=0.76; AUCSJS=0.76) for the NADP and ADDWoR groups, and (AUCCV=0.80; AUCCSA=0.80; AUCSJS=0.72) for the ADDWR and ADDWoR groups. While the diagnostic accuracy of MJS for the comparison in NADP versus ADDWR and ADDWR versus ADDWoR was respectively AUC(NADP-ADDWR)=0.73, and AUC(ADDWR-ADDWoR)=0.69. Conclusions: CV, CSA, SJS, and MJS were significantly associated with the different disc displacement status, and the condyle in TMJ ADD exhibited three-dimensionally altered dimensions. They could be considered as promising biometric markers to diagnose the ADD status.

A study of the vibrations of a rotor bearing suspended by a hybrid spring system of shape memory alloys

Abstract The study of rotor-bearing vibration is crucial across various fields, encompassing applications such as rotating machinery, wind turbines, washing machines, and elevators. However, operational challenges can arise from these machines’ propensity to vibrate under specific conditions. To address this issue, the current research investigates the utilization of shape memory alloy (SMA) springs as intelligent materials in the rotor suspension system. SMA’s unique property of changing stiffness with temperature-induced phase shifts is harnessed, leading to the construction of a test rig for validating vibration characteristics. A novel hybrid bearing is devised to effectively manage vibrations, particularly in resonance zones. To the authors’ knowledge, this new model is never reported in the literature. Then, an accelerometer is employed to measure the rotor shaft response corresponding to disc position vibration signals. Furthermore, a numerical model is developed to validate experimental results, taking into account the phase change of SMA springs and the disc’s influence on the rotor bearing’s natural frequency. Temperature variations from 20 to 80°C resulted in a 13% change in natural frequency for the hybrid spring configuration. The experimental findings align closely with ANSYS simulations, displaying an acceptable error ratio, with the highest error remaining within 20% thresholds.

Imaging evaluation of disc position and status after temporomandibular joint arthroscopic disc repositioning and suturing surgery

ObjectiveThis study aimed to explain the change of disc position at different over-corrected place after arthroscopic disc repositioning and suturing surgery. Study designPatients treated with temporomandibular joint arthroscopic disc repositioning and suturing surgery were reviewed. All patients underwent magnetic resonance imaging (MRI) before, immediately after surgery and at 2-year follow-up. The position of disc was checked and the change was compared. Results133 patients were included in the final analysis with 203 TMJ sides. The incidence rate for anterior movement of the disc after surgery was 33.0 %. Disc repositioned between 12 and 1 o'clock showed smaller movement rate of 22.6 %, while higher movement rate of 53.6 % was seen when repositioned between 2 and 3 o'clock. ConclusionsAfter arthroscopic disc repositioning and suturing surgery for ADD patients, the repositioned disc showed tendency to move forward. 12 to 1 o'clock was optional disc site for repositioning while excessive over-correction was not recommended.

Programmatically Localizing Diabetic Retinopathy Features in 45-Degree Retinal Photographs Using Anatomical Colocation

Background: The aim in this study was to investigate the localization of diabetic retinopathy features at the posterior pole. Methods: This study extracted diabetic retinopathy feature locations from 757 macula-centered 45-degree fundus photographs in the publicly available DDR dataset. Arteriole and venule locations were also extracted from the RITE (n = 35) and IOSTAR (n = 29) datasets. Images were normalized to collocate optic disc and macula positions, and feature positions were collated to generate a frequency distribution matrix. Sørensen–Dice coefficients were calculated to compare the location of different features. Results: Arterioles occurred in two main, distinct arcuate patterns. Venules showed a more diffuse distribution. Microaneurysms were diffusely located around the posterior pole. Hemorrhages and exudates occurred more frequently at the temporal aspect of the macula. Cotton wool spots occurred in a region approximating the radial peripapillary capillaries. Intraretinal microvascular abnormalities and neovascularization were seen throughout the posterior pole, with neovascularization at the disc (n = 65) being more common than neovascularization elsewhere (n = 46). Venous beading occurred primarily between the first and third bifurcations of the venules. Diabetic retinopathy overall was more frequent in the temporal aspect of the macula. The location of cotton wool spots and exudates showed moderate similarity (0.52) when all data were considered, reducing to low similarity (0.18) when areas of low frequency were removed. Conclusions: Diabetic retinopathy occurs throughout the posterior pole but is more frequent in the temporal aspect of the macula. Understanding the location of diabetic retinopathy features may help inform visual search strategies for diabetic retinopathy screening.

Analysis of joint protein expression profile in anterior disc displacement of TMJ with or without OA.

Anterior disc displacement (ADD) is a common clinical issue and may cause osteoarthritis (OA). However, the research of protein changes in synovial fluid as disease development marker and potential treatment clue is still insufficient. We conducted the high-resolution mass spectrometry (MS) of synovial fluid collected from 60 patients with normal disk position to ADD and ADD with osteoarthritis (OA). The proteins with significant changes among the 3 groups were analyzed by biological information and further validated by in primary rat condyle chondrocytes and OA animal model. FGL2, THBS4, TNC, FN1, OMD etc. were significantly increased in ADD without OA (p < 0.05), which reflected the active extracellular matrix and collagen metabolism. FGFR1, FBLN2, GRB2 etc. were significantly increased in ADD with OA group (p < 0.05), which revealed an association with apoptosis and ferroptosis. Proteins such as P4HB, CBLN4, FHL1, VIM continuously increase in the whole disease progress (p < 0.05). Both the invitro and invivo results are consistent with protein changes detected in MS profile. This study firstly provides the expression changes of proteins from normal disc condyle relationship toward ADD with OA, which can be selected and studied further as disease progress marker and potential treatment targets.

Comparison of disc position stability and condylar bone remodelling between two open disc repositioning surgeries: a retrospective single-centre cohort study.

Open suturing (OSu) and mini-screw anchor (MsA) are two commonly used open disc repositioning surgeries for anterior disc displacement (ADD) of the temporomandibular joint (TMJ). This study assesses the differences in disc position stability (DPS) and condylar bone remodelling (CBR) between these two surgical procedures in a single centre. A retrospective cohort study using MRI scans (pre-operation, 1 week and 12months post-operation) of all patients who had open TMJ disc repositioning surgery from January 2016 to June 2021 at one centre through two surgical techniques (OSu and MsA) was performed. The predictor variable was technique (OSu and MsA). Outcome variables were DPS and CBR. During follow-up, DPS was rated as good, acceptable and poor, and CBR was graded as improved, unchanged, and degenerated. Multivariate analysis was used to compare the DPS and CBR at 12 months after adjusting five factors including age, sex, Wilkes stage, preoperative bone status (normal, mild/moderate abnormal) and the degree of disc repositioning (normal, overcorrected, and posteriorly repositioned). Relative risk (RR) for DPS and CBR was calculated by multivariate logistic regression. Three hundred eighty-five patients with 583 joints were included in the study. MRIs at 12 months showed that 514 joints (93.5%) had good DPS, and 344 joints (62.5%) had improved CBR. Multivariate analysis revealed that OSu had higher DPS (RR=2.95; 95% CI, 1.27-6.85) and better CBR (RR=1.58; 95% CI, 1.02-2.46) than MsA. Among the factors affecting DPS, females had better results than males (RR=2.63; 95% CI, 1.11-6.26) and overcorrected or posteriorly repositioned discs were more stable than normally repositioned discs (RR=5.84; 95% CI, 2.58-13.20). The improvement in CBR decreased with age increasing (RR=0.91; 95% CI, 0.89-0.93). Preoperative mild/moderate abnormal bone status had a higher probability of improved CBR compared to normal preoperative bone status (RR=2.60; 95% CI, 1.76-3.83). OSu had better DPS and CBR than MsA. Sex and the degree of disc repositioning impacted DPS, while age and preoperative bone status affected CBR.

Deep convolutional neural network for glaucoma detection based on image classification

PURPOSE: Many researchers have found that the improvement in computerised medical imaging has pushed them to their limits in terms of developing automated algorithms for the identification of illness without the need for human participation. The diagnosis of glaucoma, among other eye illnesses, has continued to be one of the most difficult tasks in the area of medicine. Because there are not enough skilled specialists and there are a lot of patients seeking treatment from ophthalmologists, we have been encouraged to build efficient computer-based diagnostic methods that can assist medical professionals in early diagnosis and help reduce the amount of time and effort they spend working on healthy situations. The Optic Disc position is determined with the help of the LoG operator, and a Disc Image map is projected with the help of a U-net architecture by utilising the location and intensity profile of the optic disc. After this, a Generative adversarial network is suggested as a possible solution for segmenting the disc border. In order to verify the performance of the model, a well-defined investigation is carried out on many retinal datasets. The usage of a multi-encoder U-net framework for optic cup segmentation is the second key addition made by this proposed work. This framework greatly outperforms the state-of-the-art in this area. The suggested algorithms have been tested on public standard datasets such as Drishti-GS, Origa, and Refugee, as well as a private community camp-based difficult dataset obtained from the All-India Institute of Medical Sciences (AIIMS), Delhi. All of these datasets have been verified. In conclusion, we have shown some positive outcomes for the detection of diseases. The unique strategy for glaucoma treatment is called ensemble learning, and it combines clinically meaningful characteristics with a deep Convolutional Neural Network.

Brake disc positioning and defect detection method based on improved Canny operator

AbstractFirstly, the Canny operator combined with circle fitting is used to position the working surface. Secondly, the median filter and the Laplacian operator are selected for preprocessing. Due to uneven illumination, surface texture, or environmental dust, the extracted scratches exhibit fragmentation, and traditional morphological operations cannot handle scratches well, so an improved Canny operator combined with probabilistic Hough transform is proposed for scratch connection. A bidirectional connection is introduced to optimize the edge detection process of the Canny operator, and a parallel algorithm is introduced to shorten the detection time. Finally, the standard Hough transform needs to traverse the entire parameter space, and the calculation is complicated, and the probability Hough transform is selected. The experimental results show that compared with the traditional Canny algorithm, the precision, recall, and F1‐score of the improved Canny algorithm are increased by 3.2%, 13.2%, and 6.0%, respectively. After adding parallel processing, the average detection time was reduced by 45 ms. Finally, the accuracy of scratches extracted using this algorithm reached 97.96%, the leak rate, and mistake rate of this study are only 3.33% and 2.00%, which provides a more accurate and efficient theoretical support for the research on brake disc scratch detection.

A parametric study of a bolted joint rotor-bearing system with an unbalanced offset disk

The turbine disk is the core component of an aero-engine whose position and unbalanced force seriously affect the vibration stability of the rotor system. Ignoring the influence of the offset disk may result in discrepancies between real-world scenarios and numerical simulation results. The present work aims to explore the nonlinear dynamic characteristics of rotor systems under the coupling of bolted joint and offset disk effect, as well as the influence of offset disk position and its unbalanced force on the system dynamic behavior and bending stiffness of bolted joint also investigated. The governing equations of a bolted joint rotor-bearing system with an offset disk were established based on the finite element method and derived as a dimensionless expression in the first. Then, the Newmark method was employed for the numerical solution of the motion equations, and then a bifurcation analysis of the rotor system and the evolution of bending stiffness for the bolted joint was studied. Next, by comparing the frequency-amplitude diagrams, bifurcation diagrams, time history, shaft obits, and bending stiffness diagrams of the bolted joint, the effect of the offset disk position and its unbalanced force on the nonlinear system dynamic was revealed. Finally, an experimental study was carried out to verify the numerical result using the bolted joint rotor test rig with an offset disk. The analysis result of the present work can provide theoretical guidance for structure design and stability analysis on the aero-engine.

Factors Influencing Mandibular Deviation: A Retrospective Clinical Study.

This study aimed to investigate the correlation between mandibular deviation (MD) and possible clinical factors in patients with anterior disc displacement (ADD). This retrospective clinical study enrolled 296 patients with ADD, diagnosed using magnetic resonance imaging, from 2015 to 2018. The clinical symptoms and medical histories of these patients were carefully examined and recorded. Mandibular deviation was the primary outcome variable confirmed by a combination of clinical examination and facial photographs or posteroanterior cephalograms. The primary predictor variable was ADD staging. Secondary predictor variables included condylar height and distance of disc displacement. Other predictor variables were age, sex, disease course, oral parafunctions, depression, and bone mineral density. We used logistic regression to examine the correlation between the MD and all predictor variables. The χ2 test and analysis of variance were used to exclude the correlation between the predictor variables. In this study, the prevalence of MD was 77% among 278 patients with ADD. Bilateral ADD staging significantly contributed to MD on both sides. The odds ratio increased with the deterioration of disc displacement. The present study demonstrated that the ADD staging influences the condylar height and MD, and that articular disk position should be considered while treating MD.

Correlation between TMJ Space Alteration and Disc Displacement: A Retrospective CBCT and MRI Study.

This study aims to determine if a large anterior and reduced posterior/superior joint space is highly predictable for disc displacement. From patients with temporomandibular disorders symptoms, fifty-two experimental joints and fourteen control joints were included. The cone beam computed tomography (CBCT) images were used to calculate posterior-to-anterior (P-A) and superior-to-anterior (S-A) joint space ratios, while disc position was determined using magnetic resonance imaging (MRI). One-way analysis of covariance test and receiver operating characteristics analysis were carried out. The results showed that among the 52 experimental joints, 45 were diagnosed as disc displacement and 7 as normal disc positions (N). All 14 control joints showed normal disc positions. The P-A ratio was 1.46 ± 0.21, 0.99 ± 0.23, and 0.86 ± 0.30 in the control, N, and DD groups, respectively (p < 0.001). The S-A ratio was 1.80 ± 0.27, 1.44 ± 0.33, and 1.08 ± 0.35 in the control, N, and DD groups, respectively (p < 0.001). When an altered P-A ratio and/or S-A ratio are observed on the CBCT, the diagnosis of disc displacement is quite predictable with high sensitivity and specificity.