Orthodontics & Craniofacial Research最新文献

Objectives: To evaluate the reliability of the registration of occlusal contacts through intraoral scanning in comparison with those obtained with the aid of carbon paper.

Materials and methods: The occlusal registration was obtained at the beginning of the orthodontic treatment of 35 patients (23 men and 12 women), aged 15 to 30 years. All patients were scanned with iTero Element (Align Technology, CA, USA), occlusal records were also performed with carbon paper (AccuFilm - 8 μm, USA) and recorded in occlusograms. To verify the agreement between the two methods, the percentages of agreement and disagreement and kappa statistics were applied.

Results: There was poor agreement between occlusal contacts recorded by intraoral scanning and those obtained with carbon paper in most of the sample (Kappa value 0.07 to 0.20). Most contacts were registered in the posterior region. It seems that the contacts registered as intense in the iTero, correspond to the contacts with the carbon paper.

Conclusions: The occlusal records by means of scanning and carbon paper presented poor agreement, but the association of both methods is indicated for the correct registration of the occlusion.

Objective: The study evaluates the impact of thickness and trimming geometry on the magnitude and distribution of transverse forces applied by thermoformed plastic aligners during maxillary arch expansion.

Methods: A randomised experiment evaluated 60 aligners fabricated from PET-G in two distinct thicknesses (0.03 and 0.040 in.) and three different trimming geometries (G1-scalloped margins, G2-straight margins with 5 mm width and G3-straight margins with 10 mm extension). Transverse forces in the canine (C), first premolar (FP), second premolar (SP), first molar (FM), second molar (SM) and third molar (TM) were measured in newtons (N). Three measurement repetitions (original data plus two replicates) were implemented to generate sufficient degrees of freedom for the sum of squares of the error.

Results: The maximum transverse force in the canine region was exerted by the PET-G aligner with a thickness of 0.040 in., with no significant difference observed between the G2 and G3 straight trim lines. However, the G1 scalloped trim line exerted significantly lower transverse forces. The G3 geometry with a 0.040-in. Polymer thickness consistently generated the highest forces in the premolar and molar regions. The average transverse forces decreased in an antero-posterior direction, with the highest force observed in the canine region and the least in the molar region.

Conclusions: The thickness and trimming pattern of orthodontic aligners significantly influence force delivery during transverse expansion. Transverse forces during expansion with aligners progressively reduce from the anterior to the posterior region.

Objective: To investigate postsurgical rotational flare between the proximal and distal segments of the mandible following mandibular setback surgery using three-dimensional analysis.

Materials and methods: Cone-beam computed tomography scans from 30 patients who underwent bilateral sagittal split ramus osteotomy were analysed. To minimise the influence of bone remodelling, the proximal segment (PS) at T1 (post-surgery) was superimposed onto the T2 (post-treatment) PS using stable reference areas, excluding the osteotomy sites, condyle, and gonial angle, to generate a modified T2 model. The T1 and modified T2 were then superimposed on the distal segment (DS), which served as the reference. Displacements of the medial and lateral condylar poles, coronion, and gonion were measured with respect to the DS.

Results: When assessed using the DS as reference, the medial pole, lateral pole, and coronion showed significant posterior displacements (1.21, 1.57, and 1.24 mm; p < 0.001). Coronion also moved superiorly (0.74 mm, p < 0.001) and laterally (0.43 mm, p = 0.004), while gonion moved medially (0.65 mm, p < 0.001) without significant anteroposterior change (p = 0.468). No significant correlation was found with setback amount, vertical bony step, or its resolution.

Conclusion: The PS exhibited counterclockwise rotational flare and anterior-outward/posterior-inward yawing in relation to the DS. Incorporating surgical compensation for anticipated rotational flare-related relapse may enhance the predictability of mandibular setback outcomes.

To compare the extent of root resorption, assessed via three-dimensional (3D) volumetric CBCT analysis, between tooth-borne and bone-borne rapid maxillary expansion (RME) devices. A systematic search of seven databases (PubMed, Cochrane Library, Embase, etc.) up to December 2024 identified eligible studies (randomised controlled trials, cohort studies, clinical trials) evaluating CBCT-measured root resorption in patients treated with tooth-borne, bone-borne or hybrid RME devices. Data were analysed using STATA 17.0, employing weighted mean differences (WMDs) and random/fixed-effects models. Heterogeneity, subgroup analyses and publication bias were assessed. Sixteen studies (525 patients, 2906 teeth) were included. These studies comprised randomised controlled trials and observational studies, predominantly enrolled adolescent and young adult patients, and directly compared tooth-borne and bone-borne RME devices. Tooth-borne RME resulted in significantly greater root resorption volume compared to bone-borne devices (WMD = -10.4 mm³, 95% CI [-13.9, -6.9], 95% prediction interval [-11.94, -8.92], p < 0.05; I² = 98.8%). Tooth-borne RME also caused greater root length loss (WMD = -0.14 mm, 95% CI [-0.21, -0.08], 95% prediction interval [-0.20, -0.08], p < 0.05; I² = 95.6%). Tooth-borne RME resulted in significantly greater root resorption volume (WMD = -20.7 mm³) and length (WMD = -0.40 mm) compared to baseline, indicating increased resorption. Three-dimensional CBCT analysis demonstrated superior sensitivity in detecting resorption morphology and localization compared to linear measurements. Bone-borne RME devices, which are associated with reduced root resorption risks, may be related to improved force distribution to bony structures. Three-dimensional volumetric CBCT assessment provides a more accurate quantification than linear measurements. Clinically, bone-borne expanders are recommended for high-risk patients, while tooth-borne users require close CBCT monitoring. Findings should be interpreted considering limitations of the included evidence, including heterogeneity in RME devices and protocols, risk of bias in some non-randomised studies, and imprecision due to limited sample sizes in subgroup analyses and lack of long-term data. Trial Registration: International Prospective Register of Systematic Reviews (PROSPERO) registration number: CRD420251018535.

To summarise the scientific evidence from systematic reviews on the differences between fixed functional appliances (FFA) with and without skeletal anchorage for the treatment of Class II malocclusion in growing patients. A systematic search on six major databases was performed. Primary outcomes were changes in Co-Gn, SNB angle and the lower incisor inclination. ROBIS tool to assess risk of bias and GRADE instrument to assess evidence quality were used. Mean differences (MD) or risk ratios (RR) with their 95% confidence intervals were calculated from random-effects meta-analyses. A total of 10 systematic reviews were identified, six at high risk of bias, three at unclear risk of bias and one at low risk of bias. The meta-analysis with only RCTs studies indicated that FFA with skeletal anchorage did not produce a statistically significant increase in Co-Gn (pooled MD = +1.37 mm, 95% CI from -0.88 to 3.62; p = 0.23, I² = 96%, three studies, GRADE low). No statistically significant differences were identified for SNB angle between FFA with and without skeletal anchorage (pooled MD = +0.31 degrees, 95% CI from -0.03 to 0.66; p = 0.08, I² = 51%, three studies, GRADE low). FFA with skeletal anchorage showed a statistically greater decrease for lower incisor inclination (pooled MD = -5.03, 95% CI from -8.49 to -1.58; p = 0.004, I² = 89%, four studies, GRADE low). Low evidence of findings from exclusively RCTs studies suggested that FFA with skeletal anchorage could reduce the lower incisor inclination with a greater percentage of complications. However, no significant differences were found for mandibular dimensions and mandibular protrusion between FFA with and without skeletal anchorage.

Objectives: This study aims to investigate the effects of low-level laser therapies (LLLTs) with four different wavelengths (532, 650, 810 and 940 nm) on new bone regeneration during inter-premaxillary suture expansion in rats.

Materials and methods: Sixty rats were divided into five groups (n = 12): control (Group A) and four laser groups (Group B: 940 nm, Group C: 810 nm, Group D: 650 nm and Group E: 532 nm). Each group was further divided into two subgroups (n = 6) based on the sacrifice day: Day 7 and Day 14. The upper incisors of the rats were drilled, and a 30-g force expansion appliance was inserted. The study lasted 14 days, with 7 days of expansion and 7 days of retention. LLLT was administered at 48-h intervals in groups other than the control group. Bone regeneration in the suture was assessed using micro-computed tomography and immunohistochemistry. Trabecular number (Tb.N), trabecular thickness (Tb.Th) and trabecular separation (Tb.Sp) were measured by using micro-computed tomography. Alkaline phosphatase (ALP), bone morphogenetic protein 2 (BMP-2) and tartrate-resistant acid phosphatase (TRAP) immunoreactivity intensities were calculated in the immunohistochemically stained upper jaw sections.

Results: In Group B (940 nm), ALP was significantly higher on the 7th day (p < 0.001); ALP and BMP-2 were significantly higher (p = 0.002; p = 0.013, respectively), and Tb.Sp was significantly lower on the 14th day (p = 0.034) compared with the control group.

Conclusions: The results show that 940 nm low-level laser therapy accelerates bone regeneration more effectively in the expanded inter-premaxillary suture.

Introduction: The aim of this study was to develop and apply an artificial intelligence (AI) algorithm to aid the clinical decision-making process for managing mandibular retained second deciduous molars (SDM) with no permanent successors using machine learning.

Methods: This retrospective study consisted of patients who were diagnosed with at least one congenitally missing (agenic) mandibular permanent second premolar with a retained SDM. Pretreatment clinical records from each patient were collected and three sets of input features (radiographic, photographic and clinical) were used. The sample was divided into three groups, each representing a distinct treatment decision: (1) extraction of the SDM with space closure; (2) extraction of the SDM with space maintenance; and (3) retention of the SDM. The treatment decisions were based on majority treatment determination by three experienced clinicians. Four machine learning models were built and evaluated: Multinomial Logistic Regression, Multilayer Perceptron, Decision Tree and Random Forest classifier.

Results: Random Forest classifier showed the highest accuracy in treatment planning while Decision Tree showed the lowest accuracy. Features such as patient preference for restoration, amount of mandibular arch crowding and ankylosis were the strongest predictors, having the greatest influence on treatment decision accuracy in the Random Forest classifier model.

Conclusions: The Random Forest classifier demonstrated the highest accuracy in aiding the clinical decision-making process for managing retained SDM with no permanent successors. Key factors influencing treatment decision accuracy included patient preference for restoration, mandibular arch crowding and ankylosis.

Background: Malocclusions are significantly more prevalent among individuals with physical and mental disabilities. Head posture, particularly in wheelchair-bound individuals, may play a role in craniofacial growth and occlusal development, but its specific impact remains poorly understood.

Objective: To evaluate head posture in wheelchair-bound individuals and assess potential correlations with malocclusion characteristics.

Methods: Twenty wheelchair-bound participants (aged 6-30 years) were categorised into three groups based on their head control (full, partial, or no control). Head posture was dynamically measured on three axes (pitch, roll and yaw) using an Inertial Measurement Unit for precise 3D tracking. Malocclusions, including molar and canine sagittal relationships, overjet, overbite and crossbites, were assessed through standardised clinical examinations.

Results: All wheelchair-bound participants showed significantly greater deviations in head posture compared to controls. The roll axis differed significantly across groups (p = 0.004), with the no control group exhibiting the greatest deviation. A significant correlation was observed between pitch axis deviation and sagittal molar relationships (r = -0.59, p = 0.006), indicating that a backward head posture was associated with Class II malocclusion, while a forward head posture was linked to Class III malocclusion. No significant correlations were found for the roll or yaw axes.

Conclusion: Significant head posture deviations were detected in wheelchair-bound individuals, with those having no head control showing more extreme deviations. This study found significant correlations between antero-posterior head posture deviations and sagittal molar relationships in wheelchair-bound individuals, suggesting that head posture could be a contributing factor to malocclusions in this population. Given the limited sample, these results should be interpreted cautiously.

Objective: Mandibular retrognathism (MR) is a skeletal malocclusion in which patients have a deficient mandibular length, resulting in a more posterior position of the mandible. We aimed to investigate the association between Single nucleotide polymorphisms (SNPs) in Fibroblast Growth Factor Receptor 2 (FGFR2) gene and MR in germans.

Materials and methods: Genomic DNA and lateral cephalometric radiographs were obtained from orthodontic patients. Patients were allocated into the 'Retruded' group (SNB angle < 78°) and into the 'Well-positioned' group (SNB 78°-82°). The rs4752566, rs10736303, rs11200014, rs1078806, rs1219648, rs2981578 and rs2162540 SNPs were genotyped using real-time PCR. Allele, genotype and haplotype frequencies were compared (α = 5%).

Results: A total of 142 patients were included, 93 (65.5%) allocated into the 'Retruded' group and 49 (34.5%) into the 'Well-positioned' group. The allele T in rs2981578 SNP was statistically more frequent in the 'Retruded' group in both univariate (PR = 1.22; 95% CI, = 1.02-1.47) and multivariate (PR = 1.55; 95% CI, = 1.07-2.25) analyses (p < 0.05). The CT + TT genotypes were statistically more frequent in the 'Retruded' group in univariate (PR = 1.58; 95% CI, = 1.03-2.41) and multivariate (PR = 1.59; 95% CI, = 1.11-2.26) analysis (p < 0.05). All studied SNPs were associated with MR establishment in haplotype analysis (p < 0.05).

Conclusion: SNPs in the FGFR2 are associated with MR and have the potential to serve as genetic biomarkers to early diagnosis and prediction of mandible growth.

Objectives: To evaluate the influence of anterior bite turbos (ABT) on pulpal blood flow (PBF) changes in maxillary central incisors using Laser-Doppler Flowmetry (LDF).

Materials and methods: Sixty-one patients with deep overbite were divided into two groups. Group I received 0.014 nickel titanium (NiTi) arch wire and composite ABT on the upper central incisors to correct the deep overbite; the second group (control group) received 0.014 NiTi arch wire only. LDF was used to measure the PBF at different time points (at baseline, 20 min, 48 h, 1 week, and 1 month after activation). The baseline PBF (without orthodontic force) was compared to the corresponding PBF measurements at the designated time intervals within each group. Changes in PBF between the two groups were compared to assess the impact of ABT on pulpal circulation.

Results: Complete data were obtained for 55 patients. PBF decreased significantly after force application in both groups and reached its maximum drop after 48 h. After 30 days, the average PBF values returned to baseline values in Group II but remained slightly less than basal values in Group I (0.4 mm/s). No statistically significant difference in PBF changes between the two groups at any time point. The overall change from 20 min to 48 h was greater in the bite turbo group than in the control group; however, this difference was not statistically significant (p = 0.078).

Conclusions: Using ABT does not cause irreversible changes to pulpal vasculature.