Search Results (2,326)

Background/Objectives: Mandibular asymmetry is a common morphological alteration in orthodontics and orthognathic surgery, generally diagnosed with panoramic radiographs despite their limitations. Automated processing systems offer a promising alternative for improving its detection and analysis. The aim of this study was to develop a pilot computational model to detect and measure mandibular asymmetry in the body and ramus by analyzing anatomical distances in digital panoramic radiographs of adults. Methods: This was a descriptive observational pilot study, carried out on 30 digital panoramic radiographs of young adult patients (15 men, 15 women). Three craniometric points (Condylion, Gonion and Gnathion) were used as references landmarks. An algorithm was implemented in Python^® (v3.12) with OpenCV to extract anatomical coordinates and calculate Euclidean distances (Go-Gn, Co-Go) from pixels to millimeters. Data were statistically analyzed in SPSS (v23.0) using normality tests, paired t-tests, Wilcoxon tests, and Mann–Whitney U tests (p < 0.05). Results: No significant differences were observed in mandibular lengths by sex, with men having greater lengths in both the body (80.63 mm vs. 73.86 mm) and the ramus (55.82 mm vs. 49.15 mm). In addition, significant differences were found in total mandibular ramus measurements (p = 0.023). A classification of asymmetry by severity was proposed (mild: ≤3 mm, moderate: 3–6 mm, severe: >6 mm), with mild asymmetries being the most frequently found. The model showed reliable processing capacity. Conclusions: This pilot study shows the feasibility of using Python for automated measurement of mandibular asymmetry in panoramic radiographs and highlights its future potential for neural network integration and diagnostic-epidemiological use. Full article

Background: Mandibular advancement devices (MADs) are widely used for mild-to-moderate obstructive sleep apnea (OSA). We aimed to synthesize recent evidence on their clinical effectiveness and tolerability. Methods: A systematic review was conducted. Ten studies were included, evaluating MAD therapy in adults with mild-to-moderate OSA. The review reported on standard outcomes, including the apnea-hypopnea index (AHI), oxygenation, daytime sleepiness (Epworth Sleepiness Scale, ESS), quality of life, adherence, and adverse events. Risk of bias was also assessed. Results: Across the included studies, MADs consistently reduced AHI from baseline and improved ESS and/or snoring. In head-to-head comparisons, MADs generally yielded smaller reductions in AHI than CPAP but achieved comparable improvements in symptoms and quality of life, with higher nightly adherence. Reported adverse effects were mostly mild and transient. Conclusions: MAD therapy is an effective and generally well-tolerated option for adults with mild-to-moderate OSA and for the patients intolerant to CPAP, although average AHI reduction is smaller than with CPAP. Given the low certainty and heterogeneity of current evidence, high-quality randomized trials with objective adherence tracking and standardized titration are needed. Full article

Background/Objectives: Thyroid hormone deficiency may impair bone metabolism, but its mandibular impact remains uncertain. We aimed to compare the prevalence of altered Mandibular Cortical Index (MCI; C2–C3) and Panoramic Mandibular Index (PMI) on digital panoramic radiographs in adult women with primary hypothyroidism versus euthyroid controls, considering age and key clinical covariates. To our knowledge, this is the first study out of Spain addressing this question. Methods: This is a cross-sectional study (September 2021–June 2024) of 179 white women recruited at a university clinic. Cases were on L-thyroxine for ≥6 months, with TSH > 4.5 mIU/L and normal FT4; controls were euthyroid and untreated. Demographics, reproductive history, and BMI were recorded. Panoramic radiographs (Ratograph EVO 3D; 72 kV, 6 mA, 14.4 s) were analysed; MCI was graded (Klemetti C1–C3) distal to the mental foramen; PMI and mandibular cortical width (MCW) were measured bilaterally. Results: Women with hypothyroidism showed higher BMI and a greater number of years since menopause; age was slightly higher, but the difference was not significant. MCI distribution did not differ between groups (C3 and C2–C3, both p > 0.45). PMI (left/right) was similar (p = 0.253/0.160). Left MCW was higher in hypothyroidism in a crude analysis (4.86 ± 0.98 vs. 4.46 ± 0.94 mm; p = 0.039), but lost significance after age adjustment (adjusted p = 0.191); right MCW showed no differences. Total tooth loss tended to be higher (p = 0.055) without conclusive evidence. Conclusions: In this cohort, primary hypothyroidism was not associated with a differential mandibular cortical pattern by MCI or PMI; the crude MCW difference was explained by age. These Spain-based data refine heterogeneous prior findings and indicate that, in women treated for hypothyroidism, mandibular cortical metrics largely resemble those of their euthyroid peers. Longitudinal and multicentre studies are warranted to clarify trajectories and enhance generalisability. Full article

Objectives: The current study aimed to summarize the current evidence on vertical control provided by the bonded rapid palatal expander (BRPE) in pediatric patient populations within 6 months after expansion. Methods: Relevant studies were screened independently by two researchers from the eight databases MEDLINE (PubMed), Web of Science, SCOPUS, Embase, Cochrane, LILACS (Latin American and Caribbean Health Sciences Literature), LIVIVO and Google Scholar, and supplemented by a manual search of the reference lists from studies selected for full-manuscript reading. Relevant data from lateral cephalograms taken pre- and post-expansion was extracted. A meta-analysis was performed with RStudio and a risk of bias assessment of the included articles was completed. Results: Ten relevant studies were included for data extraction, although most had a high risk of bias. The meta-analysis revealed that within 6-month retention after BRPE treatment, there were (1) slight increases in total (0.83 mm), upper (0.57 mm), and lower (0.70 mm) facial height; (2) minimum change in the palatal plane angulation (−0.01°); (3) minimum change in the occlusal angulation (−0.04°); and (4) minimal mandibular plane angulation changes with 0.01° increase in SN-GoGn angle, 0.71° increase in SN-MP angle, 0.17° increase in FMA, and 0.82° increase in PP-GoGn angle. Conclusion: Current evidence indicates that BRPEs may not control or reduce the vertical dimension significantly within 6 months after expansion. Further high-quality studies, particularly on hyperdivergent patients, are needed to clarify whether bonded expanders offer advantages over traditional banded expanders in management of the vertical dimension. Full article

This study presents detailed microstructural observations of the mouthparts and sensory organs of adult cicadomorphan species, obtained using scanning electron microscopy (SEM). Despite microstructural variation, the overall morphology of the mouthparts, comprising a three-segmented labium and a bundle of interlocking stylets (maxillae and mandibles), is highly conserved across species, supporting its evolutionary significance in sap feeding from floem, xylem, or epidermis cells. Variations in the number and shape of mandibular stylet barbs likely reflect adaptations to different host plant tissues. The presence of an identical dual interlocking system between the maxillary stylets, which is found consistently across taxa, enhances functional stability during feeding and indicates a conserved mechanism among cicadomorphans. The species studied exhibit two distinct types of salivary canal closure: hooked and T-shaped. The latter potentially represents a state linked to specialised feeding strategies, such as sap xylem feeding. On the labial tip, there are different shapes of the anterior sensory fields. This area hosts a complex array of sensilla of different numbers, including gustatory (sensilla peg, PS1 and PS2, basiconica, BS3, double basiconica, DB), olfactory (finger–like, FLS) and thermo-hygroreceptive (sensillum dome-shaped, DS, and coeloconicum, CS) types, which facilitate host detection and feeding site selection. In the posterior sensory field, sensilla contact-chemosensory (sensilla basiconica, BS1 and BS2, and sensillum trichoideum, TS) are present. Mechanosensilla chaetica (CH1–CH3) are widely distributed on the last labial segment and may contribute to labium positioning. These findings emphasise the presence of both conserved and specialised morphological traits reflecting evolutionary and ecological diversification within Cicadomorpha. Full article

Background/Objectives: Occlusal disturbances occurring during central occlusion, mandibular movements and mastication may contribute to the development of temporomandibular disorders (TMDs). To reduce the disclusion time (DT) in all mandibular contacts, a procedure known as enameloplasty can be applied. The aim of this study was to evaluate the effect of occlusion-correcting treatments on disclusion time reduction, determination of the center of force, and the distribution of masticatory forces on the right and left side, through digital occlusal analysis in patients with TMD. Methods: The single-centered, prospective study including 106 patients with TMD after 6 months of prosthetic treatment. Digital occlusal analysis was performed before and after the enameloplasty to assess occlusion time, disclusion time and symmetry of occlusal contacts. Results: Selective enameloplasty significantly reduced disclusion time in the whole study population (0.8 vs. 0.4 s; p < 0.001), with greater improvement observed in patients with inappropriate Center of Force (COF) and premature occlusal contacts. Conclusions: Digital occlusal analysis-guided selective enameloplasty effectively reduces disclusion time and can improve occlusal parameters in TMD patients. Full article

Background: Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a functional imaging modality that can quantify tissue permeability and blood flow. Due to vasculature changes resulting from radiation therapy (RT), DCE-MRI quantitative parameters should be significantly different in regions receiving a high radiation dose compared to regions receiving a low radiation dose. This study sought to determine whether a significant difference exists in post-head-and-neck-cancer (HNC)-RT DCE-MRI quantitative parameters (K^trans and v_e) between regions of the mandible receiving a high radiation dose and regions of the mandible receiving a low radiation dose. Methods: DCE-MRI was acquired from HNC subjects post-RT. The DCE-MRI quantitative parameters K^trans and v_e were obtained through Tofts model fitting. Four mandible sections (left ramus, left body, right ramus, and right body) were delineated on subject mandible contours. Two Friedman tests comparing the mean K^trans and v_e in low-dose (≤60 Gy) areas of the four mandible regions were computed. If the Friedman test determined that a significant difference for a parameter between mandible regions exists, post hoc Wilcoxon signed-rank tests were completed comparing the four mandible regions. If the Friedman test determined that there was no significant difference between mandible regions, a Wilcoxon signed-rank test was used to determine whether a significant difference exists in the parameter between high-dose (>60 Gy) and low-dose (≤60 Gy) mandible regions. Results: 48 HNC subjects were included in the analysis. The Friedman tests showed no significant difference in v_e means between mandible regions (${\chi }_{\left(3\right)}^2$ = 1.63, p = 0.44) and a significant difference in K^trans means between mandible regions (${\chi }_{\left(3\right)}^2$ = 10.29, p = 0.005). Post hoc testing between K^trans mandible regions found that the left body and right body differed significantly from the left ramus and right ramus. The Wilcoxon signed-rank test comparing the mean v_e between high- and low-dose mandible regions found a significant difference (W = 214, p = 0.00013). Conclusions: no inherent difference in the DCE-MRI quantitative parameter v_e was observed within subject mandibles, but a significant difference was observed between v_e means in high- and low-radiation-dose mandible regions. These results provide evidence of the utility of DCE-MRI to monitor mandible vasculature changes resulting from head and neck cancer radiation therapy. Monitoring post-HNC-RT mandible vasculature changes is important to initiate earlier toxicity management and ultimately improve HNC survivors’ quality of life. Full article

Background: The implant–abutment interface has been thoroughly examined due to its impact on the success of implant healing and longevity. Removing the abutment is advantageous, but it changes the biomechanics of the implant fixture and restoration. This in vitro three-dimensional finite element analytical (FEA) study aims to evaluate the distribution of von Mises stress (VMS) in abutment-free and three additional implant abutment connections composed of various titanium alloys. Materials and methods: A three-dimensional implant-supported single-crown prosthesis model was digitally generated on the mandibular section using a combination of microcomputed tomography imaging (microCT), a computer-assisted designing (CAD) program (SolidWorks), Analysis of Systems (ANSYS), and a 3D digital scan (Visual Computing Lab). Four digital models [A (BioHorizons), B (Straumann AG), C abutment-free (Matrix), and D (TRI)] representing three different functional biomaterials [wrought Ti-6Al-4Va ELI, Roxolid (85% Ti, 15% Zr), and Ti-6Al-4V ELI] were subjected to simulated static/cyclic static loading in axial/oblique directions after being restored with highly translucent monolithic zirconia restoration. The stresses generated on the implant fixture, abutment, crown, screw, cortical, and cancellous bones were measured. Results: The highest VMSs were generated by the abutment-free (Model C, Matrix) implant system on the implant fixture [static (32.36 Mpa), cyclic static (83.34 Mpa)], screw [static (16.85 Mpa), cyclic static (30.33 Mpa), oblique (57.46 Mpa)], and cortical bone [static (26.55), cyclic static (108.99 Mpa), oblique (47.8 Mpa)]. The lowest VMSs in the implant fixture, abutment, screw, and crown were associated with the binary alloy Roxolid [83–87% Ti and 13–17% Zr]. Conclusions: Abutment-free implant systems generate twice the stress on cortical bone than other abutment implant systems while producing the highest stresses on the fixture and screw, therefore demanding further clinical investigations. Roxolid, a binary alloy of titanium and zirconia, showed the least overall stresses in different loadings and directions. Full article

Objective: This study evaluates the efficacy of a novel approach to oral appliance therapy (“OAT”) for the treatment of obstructive sleep apnea (“OSA”). This novel approach utilizes a systemized, oximetry-informed, treatment protocol and a precision-custom oral appliance. Methods: Sixty consecutive patients diagnosed with OSA were treated at Sleep Better Austin (“SBA”) using a structured, multi-step protocol and a precision-custom oral appliance (ProSomnus EVO). Baseline and post-treatment apnea–hypopnea index (“AHI”) values were compared using a matched-pair design. The primary outcome was the percentage of patients achieving a residual AHI of <10 events/h. Secondary outcomes included severity classification improvement. Results: In total, 90% of patients achieved the primary endpoint, and 87% improved by at least one severity classification. The mean AHI improved by 63% from baseline with the precision-custom OAT in situ (p < 0.001). In the moderate-to-severe subgroup, AHI improved by 70%, with 100% of severe patients achieving a residual AHI of <20 and a ≥50% improvement, without patient preselection. No serious adverse events were reported, and all patients continued therapy at follow-up. Conclusions: Precision-custom OAT, when delivered through a standardized clinical protocol informed by oximetry, can be a highly effective and well-tolerated treatment for OSA. These findings support its broader adoption as a non-invasive alternative to continuous positive airway pressure (“CPAP”) and surgical interventions, particularly for patients seeking personalized, high-compliance solutions. Full article

Background: The demand for natural, minimally invasive teeth whitening solutions has led to interest in products using natural abrasives. Zirconium, known for its abrasive properties, has been suggested as a potential whitening agent, but its efficacy compared to traditional methods is underexplored. This study aims to address this gap by evaluating zirconium powder at various concentrations as a novel approach to tooth whitening while preserving the enamel surface. Materials and Methods: Forty extracted mandibular teeth (twenty anterior, twenty posterior) were allocated into four groups and brushed for 2 min with zirconia toothpaste at one of the four concentrations. Color parameters (CIE Lab*), ΔE, and WID were measured before and after brushing using a spectrophotometer; surface roughness was assessed with a profilometer. Data were analyzed with paired tests and ANOVA/Kruskal–Wallis (p < 0.05). Results: All groups showed detectable color change (ΔE > 1.2); several exceeded clinical acceptability (ΔE ≥ 2.7). WID increased in all groups, with the largest gains at 2% zirconia for posterior teeth (+31.58) and 1% or 5% for anterior teeth (+21.07, +21.19). Surface roughness decreased significantly at 0.5% (p ≈ 0.002) and increased at 5% (p ≈ 0.002); no significant change occurred at 1% and 2%. Conclusions: Zirconia toothpaste at 1–2% offers the best balance between whitening efficacy and enamel preservation, while 5% increases roughness and 0.5% produces smaller whitening results. Full article

This study aimed to evaluate how different insertion angles of titanium orthodontic miniscrews (30°, 45°, and 90°) influence stress distribution and displacement in surrounding alveolar bone using three-dimensional finite element analysis (FEA), with a focus on biomechanical outcomes at the titanium–bone interface. The 90° insertion angle generated the highest stress in cortical bone (58.2 MPa) but the lowest displacement (0.023 mm), while the 30° angle produced lower stress (36.4 MPa) but greater displacement (0.052 mm). The 45° angle represented a compromise, combining moderate stress (42.7 MPa) and displacement (0.035 mm). This simulation-based study was conducted between January and April 2025 at the Department of Orthodontics, Kocaeli Health and Technology University. A standardized 3D mandibular bone model (2 mm cortical and 13 mm cancellous layers) was constructed, and Ti-6Al-4V miniscrews (1.6 mm × 8 mm) were virtually inserted at 30°, 45°, and 90°. A horizontal orthodontic load of 2 N was applied, and von Mises stress and displacement values were calculated in ANSYS Workbench. Stress patterns were visualized using color-coded maps. The 90° insertion angle generated the highest von Mises stress in cortical bone (50.6 MPa), with a total maximum stress of 58.2 MPa, followed by 45° (42.7 MPa) and 30° (36.4 MPa) insertions (p < 0.001). Stress was predominantly concentrated at the cortical entry point, especially in the 90° model. In terms of displacement, the 90° group exhibited the lowest mean displacement (0.023 ± 0.002 mm), followed by 45° (0.035 ± 0.003 mm) and 30° (0.052 ± 0.004 mm), with statistically significant differences among all groups (p < 0.001). The 45° angle showed a balanced biomechanical profile, combining moderate stress and displacement values, as confirmed by post hoc analysis. From a biomimetics perspective, understanding how insertion angle affects bone response provides insights for designing bio-inspired anchorage systems. By simulating natural stress dissipation, this study demonstrates that insertion angle strongly modulates miniscrew performance. Vertical placement (90°) ensures rigidity but concentrates cortical stress, whereas oblique placement, particularly at 45°, offers a balanced compromise with adequate stability and reduced stress. These results emphasize that beyond material properties, surgical parameters such as insertion angle are critical for clinical success. Full article

(1) Introduction: The clinical success of dental implants depends on rapid osseointegration, which can be impaired by hydrocarbon contamination and biological aging of titanium surfaces. Chairside plasma surface treatment has emerged as a practical method to restore surface hydrophilicity and enhance early bone–implant integration. (2) Materials and Methods: This retrospective cohort study evaluated 73 plasma-treated implants placed in 47 patients from June 2023 to October 2024. Non-thermal atmospheric pressure plasma was applied immediately before placement using the ACTILINK™ Reborn system. Implant stability was assessed baseline, weekly for the first four weeks, and again at week 8 using resonance frequency analysis (ISQ). Subgroup analyses were conducted according to initial ISQ, jaw location, implant length/diameter, and final insertion torque. (3) Results: All implants healed uneventfully without a stability dip. Mean ISQ increased from 78.97 ± 5.52 at placement to 83.74 ± 4.36 at week 8 (p < 0.001). Implants with lower initial stability demonstrated the greatest relative gains, while those with very high initial stability showed minimal changes. Mandibular and shorter implants demonstrated higher stability gains compared to maxillary and longer fixtures. (4) Conclusions: Chairside plasma surface treatment was associated with progressive ISQ increases during the 8-week healing period. The greatest gains occurred in implants with lower initial stability, while very stable implants showed little change. Stability improvements were also greater in mandibular sites, shorter fixtures, and those with higher insertion torque. These findings are limited to short-term ISQ outcomes and require validation in prospective controlled trials with standardized protocols. Full article

The biomechanical performance of dental implants is affected by both abutment height and bone quality, which influence stress distribution around the implant and the preservation of surrounding bone. This study used three-dimensional finite element analysis (FEA) to assess the combined effects of these factors. Two implants with abutment heights of 3 mm and 6 mm were modeled and placed in mandibular bone blocks representing class II and class IV bone, according to Lekholm and Zarb’s classification. A static load of 150 N, inclined at 6° buccolingually, was applied during the analysis. The simulation results showed that increasing the abutment height raises stress on the implant, leading to greater stress transfer to the peri-implant bone. The von Mises stress levels were higher in the crestal cortical bone of the class IV model with a 6 mm abutment (126 MPa). Notably, peak stresses exceeding 300 MPa were localized at the implant-abutment connection. These findings suggest that abutment height is a critical factor that negatively affects the biomechanical response, especially in low-density bone, although longer abutments offer biological benefits. This highlights the importance of minimizing the crown-to-implant ratio to reduce overload, preserve bone, and prevent mechanical failure complications. Full article

Background/Objectives: Skeletal Class III malocclusion in growing patients presents therapeutic challenges. While traditional tooth-anchored facemask (FM) therapy is widely used, it may induce undesired dental effects. Bone-anchored maxillary protraction (BAMP), using either miniscrews (MSs) or miniplates (MPs), has been proposed to enhance skeletal outcomes and minimize dental compensation. The objective is to compare the efficacy of MS and MP as skeletal anchorage in the orthopedic treatment of the Class III growing patients. Methods: This systematic review and meta-analysis followed PRISMA guidelines. Five databases and manual searches were conducted without restrictions. Inclusion criteria encompassed randomized and non-randomized controlled trials assessing cephalometric outcomes in growing patients treated with MS or MP. Risk of bias was assessed with RoB 2 and ROBINS-I tools, and evidence certainty was evaluated using GRADE. A meta-analysis was performed, collecting all the statistically significant results that emerged in the 11 articles between skeletal anchorage and controls, comparing the values of the MP group with the MS group. Results: Eleven studies (seven MP, four MS) met the inclusion criteria. Both MS and MP groups showed significant maxillary advancement and improved maxillo–mandibular relationships compared to controls. Regarding vertical values, studies have reported contrasting outcomes. Soft tissue improvements were consistent in both MS and MP devices. Statistical analysis has highlighted how MP devices demonstrated more pronounced skeletal effects, while MS systems were associated with more dental effects. Conclusions: MP may be preferable when the aim is to maximize skeletal correction with fewer dental side effects, while MS can be considered in cases favoring less invasive approaches; long-term follow-up and high-quality clinical studies are needed to confirm these clinical assessments. Full article

Robin sequence (RS) is a rare congenital anomaly characterized by micrognathia, glossoptosis, and upper airway obstruction (UAO), often accompanied by a cleft palate. The Tübingen Palatal Plate (TPP), also referred to as the pre-epiglottic baton plate (PEBP), offers a non-surgical, functional orthodontic solution that improves airway patency and feeding by advancing the tongue base. This paper outlines the semi-digital clinical and technical workflow used for TPP treatment at Tübingen University Hospital. The protocol combines intraoral scanning (IOS), computer-aided design and manufacturing (CAD/CAM), and manual refinement for patient-specific appliance production. Practical steps, modifications for special cases and follow-up procedures are detailed, aiming to support clinical implementation at other centres. Based on the published literature and over three decades of experience, the protocol emphasizes safety, quality control, and interdisciplinary collaboration, with practical guidance provided to support implementation in other centres. The potential of digital workflows for data sharing, training, and multicenter collaboration is highlighted, while challenges such as the need for specialized expertise and technical resources are acknowledged. This guideline provides the first comprehensive and reproducible description of the Tübingen approach and aims to facilitate wider adoption of TPP therapy for infants with RS. Full article