The Angle orthodontist最新文献

Objectives: The aim of this study was to evaluate the effect of aging and mechanical brushing on the color stability and translucency of three-dimensionally (3D) printed and thermoformed transparent aligners (clear aligners [CAs]) of different thicknesses.

Materials and methods: Three types of CAs (Dentsply Sirona Essix [Group 1], Scheu-Dental Thermoforming Foils [Group 2], and 3D-printed Nexdent [Group 3]) in two thicknesses (0.75 mm and 1.0 mm) were used. Each group was divided into cleaned and noncleaned subgroups (n = 10). Samples were aged in artificial saliva and subjected to mechanical brushing. Color differences (ΔE00) and relative translucency parameter values (RTP00) were recorded at 1-week intervals over 4 weeks. Statistical analyses included generalized linear models and repeated measures analyses of variance (ANOVAs) for normally distributed parameters, and robust ANOVAs and Friedman tests for nonnormally distributed parameters (P < .05).

Results: Group 1 had the highest mean RTP00 values, while Group 3 had the lowest mean RTP00 values. Noncleaned CAs exhibited higher RTP00 values than cleaned CAs (P < .05). RTP00 values decreased significantly over time, with Group 3 showing notable differences between cleaned and noncleaned subgroups. Thinner materials (0.75 mm) displayed greater color changes than thicker ones (1 mm).

Conclusions: 3D-printed CAs demonstrated more significant color variation and less translucency in comparison to thermoformed CAs. Regular cleaning helps maintain translucency and color stability, but the choice of aligner material is crucial.

Objectives: To examine the relation of maxillary permanent central incisor rotation with the primary palatal margin (PPM) and overjet in the mixed dentition in complete unilateral cleft lip and palate (cUCLP).

Materials and methods: Dental casts and preorthodontic records taken before alveolar bone grafting were examined to exclude patients having permanent teeth distal to the cleft side maxillary central incisor (CS1) and mesial to the cleft. Maxillary central incisor rotation, the angle between PPM and midline, proximity of the lingual surface of the central incisor to PPM, and overjet were measured from standardized occlusal photographs of the dental casts of 54 children with repaired cUCLP (38 M, 16 F; aged 8.7 ± 1.0 years). Descriptive analysis and correlation statistics were performed.

Results: Rotations were noted in 92.6% of the CS1. Their magnitude (111.2 ± 24.2°) was significantly greater than the noncleft side maxillary central incisor (NCS1) rotations (76.7 ± 15.7°). Rotations were predominantly distolabial for the CS1 and distopalatal for the NCS1. The PPM was located within 2 mm of the lingual surface of the CS1 in 35.2% of the sample. Severe CS1 rotation existed in 48.2% of the sample and was significantly correlated with the PPM angle (r = 0.3; P = .046) and when its proximity to the PPM was within 2 mm (φ = 0.3; P = .028). Overjet was not significantly correlated with the magnitude of rotation.

Conclusions: The angle between PPM and the midline and its proximity to CS1 are associated with the severity of CS1 rotation in repaired cUCLP. Orthodontic implications are discussed.

Objectives: To evaluate the effectiveness and accuracy of clear aligners (CA) in maxillary molar distalization and rotation for nonextraction Class II correction in the permanent dentition.

Materials and methods: This systematic review of the literature (2015-2024) followed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Studies included orthodontic patients in the permanent dentition with dental Class II, mild or no skeletal discrepancies, 2-6 mm crowding, treated with CA without extractions (except maxillary third molars) or adjunctive therapies beyond Class II elastics. Data focused on maxillary molar distalization, rotation, accuracy, and complications. Risk of bias was assessed using ROBIN-I, with evidence level graded per the SBU protocol.

Results: Sixteen studies were categorized into Group A (initial aligner or distalization outcomes) and Group B (including refinements). Group B reported greater accuracy and distalization due to sequential distalization protocols, Class II elastics, and refinements. After refinements, CA achieved 1.84-2.98 mm of maxillary molar distalization with 85% maximum accuracy. First-molar rotation reached 8.09°, with 78.4% maximum accuracy. No significant vertical skeletal changes were observed. Challenges included anterior anchorage loss, buccolingual tipping of upper molars, and patient compliance monitoring. Methodological variability and participant demographics prevented a meta-analysis.

Conclusions: CA effectively achieves maxillary molar distalization and rotation in nonextraction Class II patients. Sequential distalization protocols and refinements improve treatment outcomes, whereas early incorporation of Class II elastics, combined molar movements, and compliance monitoring may enhance treatment efficiency.

Objective: To evaluate how high-frequency vibration (125 Hz) combined with light or optimal orthodontic forces affects osteoclast numbers and root volume during tooth movement in Wistar rats.

Materials and methods: Using a split-mouth design, 96 sites in male Wistar rats were randomly assigned to six groups: control, high-frequency vibration (HFV), light force (LF, 5g), light force with vibration (LF/HFV), optimal force (OF, 10g), and optimal force with vibration (OF/HFV). First maxillary molars were moved mesially using nickel-titanium (NiTi) closed coil springs. Root volume and osteoclast numbers were measured using Micro-CT and histomorphometry at Days 1, 7, 14, and 21.

Results: After 21 days, osteoclast numbers increased significantly in HFV (5.25 ± 0.48, P =. 002), LF/HFV (10.00 ± 0.41, P < .0001), OF (13.75 ± 0.48, P <.0001), and OF/HFV (15.25 ± 0.85, P < .0001) groups. Root volume decreased significantly in LF/HFV (7.75 ± 0.18 mm3), OF (6.68 ± 0.24 mm3), and OF/HFV (6.28 ± 0.14 mm3) groups compared to control (all P < .0001). HFV alone increased osteoclast numbers but did not affect root volume. The OF/HFV group showed the highest osteoclast numbers and root volume reduction. Three-way analysis of variance revealed that time, vibration, and force significantly reduced root volume (P < .0001). Notably, the interaction effects on osteoclast numbers were significant in LF group (P < .0001), but not OF group (P = .338).

Conclusions: Combined high-frequency vibration and orthodontic forces increased osteoclast numbers and root resorption. Light forces with high-frequency vibration promoted osteoclast formation while minimizing root resorption compared to optimal forces. Additionally, the duration of this combined treatment significantly affected the extent of root resorption.

Objectives: To evaluate and compare dentoalveolar changes after orthopedic treatment of growing skeletal Class II patients using either pushing or pulling force mechanics anchored to bimaxillary miniplates in comparison with deferred treatment control subjects.

Materials and methods: A total of 39 patients (24 male, 15 female; mean age 11.59 ± 0.56 years) was equally and randomly allocated to one of three study groups: pushing group (A), pulling group (B), and control group (C). Dental changes were assessed using pretreatment (T1) and posttreatment (T2) cone-beam computed tomography scans.

Results: One patient dropped out; therefore, 13, 12, and 13 patients were analyzed in groups A, B, and C, respectively. In groups A and B, overjet decreased by 7.00 ± 1.35 mm and 8.17 ± 1.4 mm, respectively. No significant change was observed in axial inclination of the mandibular incisors in either of the intervention groups between T1 and T2. Axial inclination of the maxillary incisors decreased significantly in Group B by 3.75 ± 1.71°. The sagittal position of the mandibular first molar changed significantly in Group A (4.15 ± 1.28 mm) and Group B (4.00 ± 1.41 mm). Maxillomandibular basal arch width differences were greater than -0.39 ± 1.87 mm in all study groups. No significant transverse arch measurement changes were observed.

Conclusions: The use of either pushing or pulling force mechanics using bimaxillary skeletal anchorage was effective in improving Class II dental relationships without dentoalveolar side effects. Pretreatment transverse discrepancy should be assessed to incorporate maxillary expansion into the treatment protocol for patients diagnosed with maxillary arch constriction.

Objectives: To assess three-dimensional (3D) changes in tooth position, arch dimensions, and gingival levels after mandibular total arch distalization in skeletal Class III malocclusion.

Materials and methods: Skeletal Class III patients treated with mandibular total arch distalization using interradicular temporary anchorage devices were analyzed using stepwise 3D superimposition and reorientation of serial cone beam computed tomography (CBCT) and digital casts (N = 19). After mandibular regional superimposition of pre- (T0) and post-treatment (T1) CBCTs, the mandibles were segmented and merged with the corresponding digital casts, generating reoriented, superimposed T0 and T1 digital casts. Changes in individual tooth position, arch dimensions, occlusal plane, and clinical crown height (CCH) were measured.

Results: Mandibular teeth exhibited posterior movement ranging from 1.74 to 2.50 mm with significant lateral movement of the premolars and increase of inter-premolar width by 2.15-2.66 mm (P < .05). Extrusive movement of the entire dentition excluding the second molar was noted (P < .05), inducing changes of the occlusal plane. The overall changes in CCH were limited to -0.23 to 0.16 mm. CCH significantly increased in the premolars and decreased in the first molar (P < .05).

Conclusions: Based on a stepwise digital superimposition, mandibular total arch distalization induced complex 3D changes in the mandibular arch, including distalization, extrusion, and increase of interpremolar width. Gingival margins generally were maintained, though mild-to-moderate recession was suggested in around 20% of the premolars, which may require attention.

Objectives: To compare the treatment effects of pushing or pulling force mechanics applied to bimaxillary miniplates with those of deferred treatment control patients to evaluate mandibular skeletal growth changes in growing patients with skeletal Class II malocclusion due to mandibular deficiency.

Materials and methods: Thirty-nine patients (24 males, 15 females; mean age = 11.59 ± 0.56 years) were equally and randomly assigned to one of three groups: Group A, skeletally anchored fixed-functional appliance (pushing mechanics); Group B, skeletally anchored Class II spring (pulling mechanics); and Group C, deferred treatment skeletal Class II control patients. Pretreatment and posttreatment cone-beam computed tomography scans were used for assessment of measurements (time interval: 11.52 ± 0.32, 11.53 ± 0.31, and 9.63 ± 0.22 months for groups A, B, and C, respectively).

Results: Relative to the control group, both intervention groups showed significant increases in effective mandibular length (Co-Gn), with mean differences of 5.08 ± 2.25 mm in Group A, and 3.83 ± 2.79 mm in Group B. A significant improvement in the sagittal relationship was observed in both groups, with reductions in ANB angle by 4.31° in Group A, and 5.5° in Group B. The mandibular plane angle was increased significantly in Group B by 1.83 ± 0.72°.

Conclusion: Mandibular growth was enhanced using either pushing or pulling skeletally anchored force mechanics. The use of pulling force mechanics, specifically, was associated with increases in lower facial height.

Objectives: To assess and compare the accuracy of infrazygomatic crest screws (IZC) placed with and without a dynamic navigation system.

Materials and methods: Preoperative cone-beam computed tomography (CBCT) and intraoral scan of the maxillary arch were obtained for 12 patients requiring therapeutic first premolar extraction after leveling and alignment. Virtual planning of the final IZC screw position on both sides was done using Evalunav software. Maxillary left and right arches for each patient were randomized into experimental and control sides. A 12 × 2 mm dimension IZC screw was positioned with and without use of a dynamic navigation system randomly on either side. A postoperative CBCT was taken immediately to assess the final screw position. Preoperative and postoperative CBCTs were compared for deviation in the entry point, apical point, and angular point for experimental and control sides. Mean value deviations obtained were subjected to statistical analysis using SPSS 20.0 to describe the data.

Results: Paired t-tests were used to analyze the comparisons. Dynamic navigation showed a statistically significant difference in entry point and angular point compared to the freehand approach during implant placement.

Conclusions: IZC screws implanted with the dynamic navigation system offered better control with less deviation and greater accuracy in all three planes of space. However, further studies are necessary to determine the stability and anchor value of implants placed with a dynamic navigation system.

Severe vertical maxillary excess (VME) is a skeletal abnormality that typically requires orthognathic surgery for correction. Nonsurgical orthodontic treatment has been a fascinating but challenging alternative, especially when adverse anatomic factors hamper or pose risks for intrusive tooth movement. Despite well-documented efficiency of temporary anchorage device (TAD)-aided nonsurgical treatment for VME, evidence is scarce regarding the treatment efficacy and safety for cases with adverse anatomic traits. In this case report, we present nonsurgical treatment of a patient with severe VME, maxillary protrusion, and retrognathism. Additional challenges included compromised periodontal health, low maxillary sinus floor, short roots with axes deviating from the center of basal bone, and thin labial cortical bone with partial deficiencies. With anchorage from a transpalatal arch (TPA) and TADs and elaborate biomechanical control strategies, significant maxillary full-arch intrusion and anterior retraction with adequate root torque control were achieved, resulting in counterclockwise mandibular rotation and notable profile improvement. One-year follow-up showed stable treatment results. This case provided evidence on how balance may be achieved between treatment efficacy and anatomical limitations using biomechanical control strategies.

Objectives: To investigate the prevalence of bullying in schoolchildren and its relationship with malocclusion, accounting for demographic and psychosocial factors.

Materials and methods: This was a cross-sectional study on 10-14-year-old schoolchildren in the United Kingdom. Clinical examination was undertaken measuring Index of Orthodontic Treatment Need (IOTN), overjet, overbite, and crowding or spacing. Questionnaires were used to measure bullying, oral health-related quality of life (OHRQoL), self-esteem (SE), loneliness, and behavioral and emotional difficulties.

Results: Of 698 participants, 68 reported being bullied (9.7%). No difference was found in prevalence for gender, ethnicity, or age. Increased prevalence was found in participants with overjet > 6 mm (P = .02) and great need for treatment (IOTN Dental Health Component 5 P < .001, Aesthetic Component 9-10 P = .008). Bullied participants reported lower OHRQoL (P < .001) and SE (P < .001) and higher levels of loneliness (P < .001), emotional symptoms (P < .001), conduct problems (P = .002), and peer problems (P < .001). Multivariate analysis showed that being bullied was related to higher levels of loneliness (P = .007), poor peer relations (P < .001), and increased overjet (P = .032).

Conclusions: Accounting for psychosocial factors, risk of being a victim of bullying was related to malocclusion, specifically an increased overjet.