Head & Face Medicine最新文献

Background: Extensive retraction of mandibular incisors in Class III treatment may increase the risk of orthodontically induced apical root resorption (OIARR). This retrospective cohort study aimed to assess the incidence and severity of OIARR in Class III patients treated nonsurgically with lingual high precision fixed appliances (HPFAs) and significant anterior tooth retraction.

Methods: Eligible for inclusion were adolescent and adult Class III patients treated with lingual HPFAs (WIN, DW Lingual Systems GmbH) and extraction of lower premolars, who completed treatment between 2015 and 2024. Pre- (T0) and post-treatment (T1) panoramic radiographs were measured for root and crown lengths, with relative root resorption (rRR, %) calculated for each tooth. Clinically relevant OIARR was assessed using the Malmgren index (scores 1-4). Statistical significance of mean rRR (%) changes was assessed using one-sample t-tests (α = 0.05).

Results: A total of 25 patients (mean age at T1 26.8 ± 9.7 years; 12 females, 13 males; mean Wits at T0 -6.7 ± 2.5 mm) and 350 mandibular teeth were analyzed. The mean rRR for anterior teeth was 3.15 ± 4.05%, with no cases of severe resorption (Malmgren score 4) and only 6.7% of roots exhibiting clinically relevant shortening (Malmgren score 3). There was no increased risk of OIARR in anterior teeth compared to premolars and molars (3.15% vs. 3.31%).

Conclusion: Extensive bodily retraction of lower anterior teeth was not associated with significant OIARR in this Class III cohort. Excellent torque control using HPFAs enabled considerable retraction with low risk of OIARR, supporting this approach as a safe nonsurgical alternative for Class III camouflage.

Objective: To evaluate the clinical efficacy of digital occlusal splints in alleviating pain and dysfunction in patients with temporomandibular disorders (TMD) and underlying mechanisms.

Methods: TMD patients were enrolled and divided into digital and conventional occlusal splint groups (n = 66/group). Clinical outcomes, including visual analog scale (VAS) scores and temporomandibular function indices [Craniomandibular Index (CMI), Dysfunction Index (DI), Palpation Index (PI)], were assessed pre- and post-treatment. Cone-beam computed tomography (CBCT) was used to analyze condylar positional changes and joint space adaptation, while quantitative polymerase chain reaction and enzyme-linked immunosorbent assay measured serum levels of inflammatory markers. Correlations between clinical, structural, and biochemical parameters were examined.

Results: Both groups exhibited significant post-treatment reductions in VAS scores, CMI, DI, and PI (P < 0.05), with the digital group demonstrating superior improvements in VAS, PI, and CMI compared to controls (P < 0.001). CBCT revealed favorable structural adaptations in both groups, though the digital group showed greater enhancements in glenoid fossa depth and medial joint space (P < 0.05). Biochemical analysis confirmed significant decreases in tumor necrosis factor-α (TNF-α), fibroblast growth factor receptor 3 (FGFR3), and nitric oxide synthase 2 (NOS2) levels, with additional reductions in nerve growth factor (NGF) and human leukocyte antigen B (HLA-B) observed exclusively in the digital group (P < 0.05).

Conclusion: Digital occlusal splints effectively mitigate TMD-related pain and dysfunction, likely through synergistic mechanisms involving occlusal stabilization, joint structural optimization, and inflammatory modulation. This technology represents a promising precision-based approach for personalized TMD management.

Background: Tissues can adhere to cold metal surfaces, causing tissue damage upon detachment. For children, this often involves the tongue, so-called tundra tongue. This study aimed to assess the risk and extent of tongue tissue damage following adhesion to cold metal lamp posts.

Methods: Eighty-four porcine tongues were acquired shortly after slaughter. The apex and basis of each tongue were separately brought into contact with a section of a cold metal lamp post and detached gradually or rapidly. Detachment force was recorded and tongues were visually inspected for macroscopic injuries. Selected tongues were assessed histologically. Finite element simulations were conducted in COMSOL Multiphysics to model intra-tissue temperature over time. Each tongue was tested twice (apex and basis), resulting in 168 experiments. Four experiments were excluded, leaving 164 for analysis.

Results: Avulsion injury occurred in 89 of 164 experiments (54%) with risk increasing with the detachment force (p < 0.001). Peak tongue detachment force was associated with contact time (p < 0.001), tongue region (apex versus basis, p < 0.01), and release type (rapid versus gradual, p < 0.001). A non-linear relationship was found between metal temperature and detachment force (p < 0.01), with peak adherence at approximately -7.5 °C. Histological evaluation demonstrated intra-epidermal damage that could be rationalized with computer modelling. Nearly all experiments (92%) caused macroscopic, but not microscopic, cold injury, with risk increasing at lower metal temperatures. Computer simulations suggest that tissue damage is related to superficial tissue freezing that occurs under typical winter conditions and short exposure times.

Conclusions: The tundra tongue is a complex phenomenon. Although the risk of avulsion injury is significant, our findings indicate limited damage potential under normal winter conditions and brief exposure times.

Background: This study aimed to investigate the feasibility and efficacy of 3D-printed nasal models for training in nasal endoscopic examination and artificial lacrimal duct intubation, while also evaluating trainees' learning experience and skill improvement.

Methods: A nasal model replicating anatomical structures was constructed using stereolithography (SLA) 3D printing based on adult nasal CT data. Twenty-four ophthalmologists subsequently underwent training involving simulated nasal endoscopic procedures and artificial lacrimal duct intubation on these models. Pre- and post-training practical assessments included the anatomical identification rate, nasal endoscopic operation time, and the success rate of artificial lacrimal duct intubation. A 5-point Likert scale questionnaire was used to measure participants' learning outcomes and satisfaction.

Results: 3D-printed model accurately replicated nasal anatomical details, encompassing the nasal cavity, nasopharyngeal structures, and precise nasolacrimal duct opening localization. Following training, participants demonstrated significantly improved anatomical identification rates (p < 0.0001) and substantially reduced endoscopic operation times (p < 0.001), further achieving a 95.8% (23/24) qualification rate for lacrimal duct implantation positioning. Notably, questionnaire feedback indicated that 91.7% of trainees agreed the model enhanced anatomical understanding; 87.5% affirmed its haptic feedback approximated real surgery; 95.8% reported increased surgical confidence; and 91.7% endorsed its use for pre-operative training.

Conclusions: 3D-printed nasal model offers a high-fidelity, reusable platform for nasal endoscopy and lacrimal surgery training, effectively advancing trainees' operative skills and confidence-thus demonstrating significant potential for clinical dissemination.

Objective: This study aimed to assess the diagnostic value of electrocochleography (ECochG) for identifying endolymphatic hydrops (EH) and to investigate whether integrating multimodal auditory data from ECochG and pure-tone audiometry (PTA) into machine learning models could improve diagnostic accuracy and clinical interpretability.

Methods: A prospective cohort of 78 patients (156 ears) with a strong clinical suspicion of EH was evaluated between March and June 2024. ECochG and PTA examinations were performed, and extracted parameters were used to develop and validate multiple machine learning models. Diagnostic performance was compared using the area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and overall accuracy.

Results: After excluding six ears with unrecordable ECochG data, 150 ears were analyzed. Models based solely on ECochG-derived features demonstrated limited diagnostic performance (maximum AUC = 0.61). When multimodal hearing data were incorporated, model performance improved substantially. The Light Gradient Boosting Machine (LightGBM) model achieved an AUC of 0.92 and an accuracy of 0.73 for predicting the anatomical distribution of EH.

Conclusions: Integrating multimodal auditory data into interpretable machine learning models can markedly improve the diagnostic accuracy of endolymphatic hydrops, providing an objective framework to support early clinical diagnosis and management. However, this study is limited by a small sample size and has not yet been validated across multiple centers.

Level of evidence: Level 3.

Objective: Mucopolysaccharidoses (MPS) represent a heterogeneous group of rare, inherited lysosomal storage disorders characterized by the accumulation of glycosaminoglycans in various tissues, including the orofacial region. This study aims to investigate the orofacial features and radiographic manifestations in a cohort of pediatric patients diagnosed with MPS.

Materials and methods: Thirty-five patients (18 males, 17 females) diagnosed with different subtypes of MPS underwent comprehensive oral and radiographic examinations. The presence and frequency of clinical and radiographic findings were documented. Radiographic analysis was feasible in 26 patients, with 9 excluded due to severe intellectual disability. The decayed, missing, and filled teeth (DMFT/dft); decayed, missing, and filled surfaces (DMFS/dfs) indices were recorded according to WHO criteria. The dental plaque scores were determined according to Silness & Löe plaque index. Data was analysed using SPSS 25.0, with descriptive statistics summarizing variables and Fisher's Exact test applied for subgroup comparisons by MPS subtype; significance was set at p < 0.05.

Results: The most frequent orofacial findings included tongue thrusting (80%, n = 28/35), limited mouth opening (71%, n = 25/35), macroglossia (71%, n = 25/35), and anterior open bite (54%, n = 19/35). Radiographic analysis revealed a thin mandibular cortex in 38% (n = 10/26) of cases, impacted teeth in 27% (n = 7/26), and a short mandibular ramus in 23% (n = 6/26). This is the first reported case of a talon cusp, a rare dental anomaly occurring in a patient with MPS-IV, highlighting a previously unrecognized association in the literature. The distribution of MPS types was: MPS-I (n = 3), MPS-II (n = 6), MPS-III (n = 8), MPS-IV (n = 10), MPS-VI (n = 7), and MPS-VII (n = 1).

Conclusions: Orofacial manifestations are frequently observed in patients with MPS and may serve as early indicators of the disorder, particularly within dental settings. Recognition of these features is essential, as they underscore the need for multidisciplinary care and routine dental evaluations to mitigate potential complications and enhance overall quality of life.

Clinical relevance: Orofacial abnormalities are common in children with MPS and may provide early clues to the diagnosis. This study emphasizes the importance of dental evaluations in identifying these signs, including the first reported case of a talon cusp in a patient with MPS. Early recognition by dental professionals can support timely diagnosis, guide appropriate referrals, and improve patient outcomes through coordinated, multidisciplinary care.