The Angle orthodontist最新文献

Objectives: To investigate the influence of attachment position and torque overcorrection on stress distribution and tooth displacement trends during arch expansion in clear aligner therapy (CAT).

Materials and methods: Dental and skeletal models were obtained from an adult volunteer with angle Class I and mild crowding. Attachments were designed on the buccal, lingual, and buccolingual surfaces of the first molar. Different overcorrection torques were designed on the first molar. The displacement and stress of the whole arch were analyzed using a three-dimensional finite element analysis model.

Results: Crown buccal tipping was observed during arch expansion, while the lingual attachment showed more buccal crown and lingual root movement. Based on the trend of displacement, 1.5° of buccal root torque overcorrection without attachments could lead to bodily movement, 1.8° with a lingual attachment, 0.5° with a buccal attachment, and 0.9° with a buccolingual attachment.

Conclusions: Arch expansion is primarily achieved by teeth tipping despite attachments placed on the buccal or lingual side of teeth in CAT. Appropriate overcorrection of buccal root torque could contribute to the achievement of bodily movement.

Objectives: To evaluate the reliability and accuracy of Keynote for tracing and analyzing cephalograms in comparison to Quick Ceph Studio.

Materials and methods: This was a cross-sectional study, which utilized the lateral cephalometric digital images (radiographs) from 49 patients. The study site was the Dental Radiology unit in the School of Dentistry of the Muhimbili University of Health and Allied Sciences (MUHAS), in Dar es Salaam, Tanzania. Cephalograms were imported to Quick Ceph Studio and then to Keynote for analysis. Minimum, maximum, mean, standard deviation, and mean difference were used to describe the data. Agreement between the two techniques was assessed by the Bland-Altman plot, linear regression, and interexaminer reliability tests. A level of significance was considered at P < .05, and a 95% CI was estimated for the outcomes in the study groups.

Results: The majority of the mean values obtained from Quick Ceph were greater (P < .05) than those obtained from Keynote. According to Bland-Altman plots, all measurements were within the limit of agreement except for only five linear variables. The interexaminer reliability test showed no agreement between the two instruments for all linear parameters except for the LAFH: TAFH, whereas all angular measurements revealed good to excellent agreement (ICC: 0.75 to 0.97) between the methods.

Conclusions: The measurements obtained with the Keynote software were found to be clinically reliable since the limits did not exceed the maximum acceptable difference between the methods. The two software instruments were considered to be in agreement and can be used interchangeably.

Objectives: To evaluate the accuracy of Invisalign ClinCheck in predicting open gingival embrasures (OGEs) and to identify predictors of OGEs in adult extraction cases.

Materials and methods: Fifty-seven adult patients treated with Invisalign and four first premolar extractions were included in this retrospective study. OGEs were measured in maxillary and mandibular anterior regions using posttreatment intraoral photographs (actual OGEs) and the final step from the first treatment plan in ClinCheck (predicted OGEs). Prediction performance indicators including precision, sensitivity, specificity, false positive rate, false negative rate, and accuracy were evaluated at each tooth site. Predictors of OGEs (age, crowding, crown morphology, tooth movement, tooth site, treatment duration, and attachment design) were analyzed using binary logistic regression.

Results: Incidence of actual OGEs was like that of the ClinCheck predicted OGEs in the maxillary and mandibular anterior regions. The predictability of ClinCheck was satisfactory in both the maxilla and mandible, with accuracy rates of 94.0% and 86.0%, respectively. The most accurate prediction was for the maxillary central incisors, achieving a precision of 100% and an accuracy of 96.6%. The most significant predictors of OGEs included patient age at initial consultation, anterior crowding, tooth crown morphology, and type of tooth movement.

Conclusions: Invisalign ClinCheck predicted OGEs in adult patients treated with four premolar extractions. The accuracy of the prediction was satisfactory, 94% in the maxilla and 86% in the mandible, demonstrating great potential for clinical application.

Objectives: To report the prevalence of pulp stones (PSs) in molars of orthodontically treated patients, investigate the impact of orthodontic treatment (ORT) using clear aligners (CAs) and fixed appliances (FAs) on the development of PSs in molars, and investigate the association between the incidence of PSs during ORT and the studied variables.

Materials and methods: Pretreatment orthopantomograms (OPGs) of 600 patients were assessed. Of those, posttreatment OPGs of 272 patients were available. Molars were subdivided into four subgroups based on type of appliance and force application: group 1, first molars included in FA (n = 707); group 2, first molars included in CA (n = 157); group 3, second molars included in CA (n = 189); group 4, second molars not included in FA during treatment (n = 880). PSs were diagnosed when radiopaque bodies were detected in the coronal and/or radicular pulp space. PS changes after treatment were recorded and analyzed using SPSS.

Results: The prevalence of PSs was 16.6%. The overall incidence of PSs increased by 5.9% and 4.5% in groups 1 and 2, and by 3.7% and 5.3% in groups 3 and 4, respectively (P ≤ .05). No significant differences were found between appliance type groups (1 and 2) and force application groups (3 and 4). The association between PS development and the type of appliance or treatment duration was not significant.

Conclusions: The incidence of PSs increased during ORT, which was more pronounced in maxillary molars. PS development during ORT was not associated with orthodontic appliance type, force application, and duration of ORT.

Objectives: To explore the relationship between changes in Peer Assessment Rating (PAR) score and Oral Health-Related Quality of Life (OHRQoL) following orthodontic treatment and to assess responsiveness of the Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) in a cohort of young adults.

Materials and methods: Participants (n = 162) aged 18-25 years requiring comprehensive fixed orthodontic treatment were recruited. Changes in OHRQoL were measured using the PIDAQ, while malocclusion severity was assessed using the PAR index and Index of Orthodontic Treatment Need. Data were collected before treatment (T0) and 1 month after treatment completion (T1). Responsiveness of the PIDAQ was evaluated using standardized effect size, standardized response mean, and Global Transition Judgment.

Results: A positive, moderate overall correlation (r = 0.417, P < .05) was observed between changes in PAR and PIDAQ scores posttreatment, with significant improvements in OHRQoL reported by 88.1% of participants at T1. Subgroup analysis revealed strong correlations in cases of crowding (r = 0.711) and increased overjet (r = 0.703), while Class III malocclusion showed a weaker correlation (r = 0.263). Multivariate regression analysis revealed that change in PAR score was independently associated (R2 = 0.652) with change in OHRQoL score. The PIDAQ demonstrated responsiveness to treatment-associated changes, with a significant reduction in OHRQoL scores posttreatment.

Conclusions: While a positive correlation between the objective measure of malocclusion severity (PAR) and subjective OHRQoL was identified, the relationship was moderate. The PIDAQ was found to be a responsive scale for assessing OHRQoL in orthodontic patients.

Objectives: To determine effects of printing layer thickness and build orientation on mechanical properties and color stability of direct 3D-printed clear aligner resin.

Materials and methods: Specimens were printed using 3D printed clear aligner resin with two printing layer thicknesses (50 µm, 100 µm) and three build orientations (90°, 60°, and 45°). Mechanical properties (tensile stress, tensile strain, and elastic modulus), color stability in coffee and artificial saliva, and roughness were then evaluated.

Results: Specimens printed with a 50 µm layer thickness and orientation at 90° demonstrated superior color stability in artificial saliva. However, all specimens showed high susceptibility to coffee staining regardless of layer thickness or orientation. Mechanical properties were improved in the order of 90° < 60° < 45° build orientation, showing statistically significant differences (P < .05). Surface roughness was increased in the order of 90° < 60° < 45° build orientation, showing statistically significant differences (P < .05).

Conclusions: Printing layer thickness and orientation exerted significant effects on mechanical properties, color stability, and surface roughness of 3D-printed clear aligner resin.

Objectives: To assess the perception of smile esthetics, variations in buccolingual crown inclination of the upper anterior teeth were introduced, disrupting the parallelism of these connectors from a frontal view.

Materials and methods: In this descriptive cross-sectional study, a close-up smile image was modified using Adobe Photoshop to adjust the angulation of connectors, affecting either the six upper anterior teeth (C/C group) or the four upper anterior teeth (LI/LI group). Orthodontists (ORs), general dentists (GDs), and laypersons (LPs) then evaluated the attractiveness of the modified smiles.

Results: A total of 79 LPs, 65 ORs, and 89 GDs participated in the evaluation. LPs gave the highest scores, followed by GDs and ORs, in both the C/C and LI/LI groups. The -6° deviated image was the least favored in the C/C group, while the -9° image received the lowest scores in the LI/LI group.

Conclusions: In this study, we highlight the importance of proper buccolingual crown inclination and parallelism of connectors during treatment. The OR group showed the most critical assessment of smile esthetics related to buccolingual crown inclination variations. Lower scores were noted for greater deformations and negative inclinations in both the LI/LI and C/C groups.

This case report describes the nonsurgical management of a patient with a Class II skeletal pattern, retrognathic mandible, steep mandibular angle, maxillary vertical excess, and lip incompetence. The treatment approach involved orthodontic mechanics supported with skeletal anchorage to achieve maximal intrusion and retraction of the dentition. A novel elastic hanging rack appliance, supported by midpalatal miniscrews, was used. A maximal anchorage setup for active vertical control on both arches was illustrated. Significant improvement in the facial profile was achieved with optimal occlusion. Cephalometric analysis revealed successful incisor retraction and intrusion, as well as a forward rotation of the mandible. The treatment outcome illustrates the impact of active vertical control on orthodontic camouflage treatment for severe protrusion.

Practitioners may face difficulties implementing research results into practice. Seven examples of common knowledge translation barriers for clinicians are presented, and suggestions are offered for building effective communication bridges. Changes in how research results are reported and interpreted across different practice contexts can improve orthodontic care. These include (a) attention to the expected benefit that includes estimates of both likely clinical value and probability of occurrence, (b) cost considerations, (c) generalizability across contexts that require interpretation adjustments, (d) measures of effect size in addition to measures of statistical significance, (e) determination of the largest relative sources of variance in the reported results, (f) estimating probabilities that lead to practice actions, and (g) conversion of research descriptions to values that impact practice decisions. Examples of improved communication relevant to clinicians are provided that can be used to build stronger bridges between orthodontic research and practice. Although advances in orthodontic research rigor have been noted, journal articles would benefit from more clinician-friendly descriptions of results and their impact.

Objectives: To evaluate nasal septum changes after rapid maxillary expansion (RME) during the mixed dentition and to verify the association between quantitative and qualitative assessments of nasal septum deviation (NSD) by ear, nose, and throat (ENT) specialists.

Materials and methods: The sample comprised 24 patients (11 male, 13 female) with a mean age of 7.62 ± 0.92 years with maxillary transverse deficiencies. Cone-beam computed tomography (CBCT) images were obtained before and after RME. Three CBCT coronal sections passing through the maxillary first molars, 5 mm anterior and 5 mm posterior, were used for quantitative assessment. NSD was calculated using the ratio of nasal cavity height to nasal septum contour. Additionally, five ENT professionals evaluated NSD qualitatively using scores from 1 to 3 through CBCT sequential axial and coronal sections. Absent NSD was scored as zero. Interstage changes were assessed using Wilcoxon tests. Spearman correlation and linear regression were performed to evaluate the association between quantitative and qualitative analyses (P < .05).

Results: No significant change was observed in the NSD ratio. In pre-expansion CBCT images, absence of NSD and scores 1, 2, and 3 for NSD were found for 45.8%, 41.7%, 12.5%, and 0%, respectively. In the qualitative assessment, no significant change in NSD was observed after expansion. A strong association was found between NSD ratio and ENT score (r = 0.750).

Conclusions: In the mixed dentition, no significant change was observed in the NSD ratio. Qualitative analysis of NSD was associated with quantitative assessment of the ratio between nasal septum contour and nasal cavity height.