The Angle orthodontist最新文献

Objectives: To evaluate the position of the chin of untreated male and female Class I growing subjects.

Materials and methods: A sample of 51 growing Class I subjects, 29 male and 22 female, from 7 to 16 years of age, was studied. The total number of 359 lateral cephalograms included at least one cephalogram for each subject taken in the early mixed dentition (younger than 10 years), one in late mixed dentition (between 10 and 12 years), and one in the permanent dentition phase (older than 12 years old).

Results: Descriptive statistics for the X component (horizontal) and Y component (vertical) of the cephalometric landmark Gnathion (Gn) were recorded. Student t-tests showed no differences between male and female growing subjects for the X component (horizontal), but significant differences for the Y component (vertical).

Conclusions: Displacement of the mandible over the timeframe studied differs between male and female untreated subjects. Although most of the orthodontic literature addresses such differences as an anteroposterior phenomenon, this study found that the difference is mainly due to the vertical, and not horizontal, component of such displacement.

Objectives: To examine retrospectively the short-term effects of a compliance-free skeletal Class III corrector (NET3-corrector) compared to rapid maxillary expansion-facemask (RME-FM).

Material and methods: Records of 20 skeletal Class III patients treated with the NET3-corrector were compared to 20 patients treated with RME-FM, mean age: 11.14 ± 1.17 years and 11.14 ± 2.06, respectively. The NET3-corrector consisted of a hybrid-expander, a lower lingual arch, and a modified PowerScope spring. The RME-FM group received an RME-facemask combination. T2 records were collected when an overjet of at least 2 mm was achieved. Differences between two timepoints within groups and differences between groups were tested using paired samples t-test and independent samples t-test, respectively (P < .05 was considered statistically significant).

Results: The treatment time was 10.5 months with NET3-corrector and 12 months with RME-FM. The NET3-corrector was well tolerated by patients and the Class III malocclusion was corrected in all patients in both groups. The overall maxillary skeletal change was greater with the NET3-corrector, with an additional 2° advancement at SNA (P < .001). Significant differences in maxillary incisor angulation were observed in the RME-FM group in comparison to NET3 (-0.37 ± 3.31 vs 4.96 ± 3.80; P < .001). The mandibular molars tipped significantly more distally in the NET3 group (7.3° more; P < .001).

Conclusions: The compliance-free tooth-bone-borne NET3-corrector, is effective in correcting Class III malocclusion with improved maxillary skeletal outcomes compared to RME-FM in the short term. These results need to be evaluated in the long term with a randomized sample.

Objectives: To evaluate root development after forced eruption of impacted maxillary canines before or after complete root development of the contralateral canine.

Materials and methods: A total of 50 patients (21 male, 29 female; mean age: 12.4 years) with unilateral impaction of maxillary canines were classified to "Immature group" with incomplete root development of the contralateral canine or "Mature group" with complete root development of the contralateral canine. Volume, total length, crown length, root length, and root/crown ratio (R/C) of the impacted canine and the contralateral canine were measured in the posttreatment cone-beam computed tomography images.

Results: In the immature group, total length and root length of impacted canines were 0.68 mm and 0.51 mm shorter than contralateral canines, respectively (P < .05). In the mature group, volume, total length, root length, and R/C of impacted canines were 37.90 mm3, 2.43 mm, 2.53 mm, and 0.26 smaller, respectively, than contralateral canines (P < .001). Crown length also showed a statistically significant difference between impacted canines and contralateral canines (P < .05). When differences between impacted canines and contralateral canines were compared between the immature and mature groups, all variables showed statistically significant differences, with the mean difference in total length and root length being 1.75 mm and 2.02 mm larger, respectively, in the mature group, (P < .001).

Conclusions: Regardless of treatment timing, total length and root length of impacted canines were shorter than those of contralateral canines. Forced eruption of the impacted canine undertaken before root development of the contralateral canine showed better root development in both linear and volumetric measurements.

Objectives: To develop facial growth prediction models using artificial intelligence (AI) under various conditions, and to compare performance of these models with each other as well as with the partial least squares (PLS) growth prediction model.

Materials and methods: Longitudinal lateral cephalograms from 33 subjects in the Mathews growth collection were utilized. A total of 1257 pairs of before and after growth lateral cephalograms were included. In each image, 46 hard and 32 soft tissue landmarks were manually identified. Growth prediction models were constructed using a deep learning method based on TabNet deep neural network and partial least squares (PLS) method. Prediction accuracies of the two methods were compared.

Results: On average, artificial intelligence (AI) showed 0.61 mm less prediction error than PLS. Among the 77 predicted landmarks, AI was more accurate than PLS in 60 landmarks. When comparing AI models with varying numbers of training epochs, those with higher epochs yielded more accurate predictions. Overall, PLS and AI exhibited greater prediction errors for soft tissue and mandibular landmarks compared to hard tissue and maxillary landmarks. However, AI showed a smaller increase in prediction error in areas with greater variability.

Conclusions: AI proved to be a valuable growth prediction method, with clinically acceptable prediction errors averaging 1.49 mm for 45 hard tissue landmarks and 1.71 mm for 32 soft tissue landmarks. PLS accurately predicted landmarks with low variability. However, AI generally outperformed PLS, particularly for landmarks in the lower part of the craniofacial structure and soft tissue, where uncertainty is considerable.

Objectives: To validate the accuracy and reliability of a graph convolutional network (GCN)-based superimposition method of a maxillary digital dental model (MDM) by comparing it with manual superimposition and quantifying the clinical error from this method.

Materials and methods: Based on a GCN, learning the features from 100 three-dimensional digital occlusal models under supervision of the palatal stable structure labels that were manually annotated by senior specialists, the palatal stable structure was automatically segmented. The average Hausdorff distance was calculated to assess the difference between automatic and manual segmentations. Tooth position and angulation, including rotation, tip, and torque, of bilateral upper first molars and central incisors were obtained to measure the clinical error of automatic superimposition. Reliability was calculated by intraclass correlation coefficient (ICC).

Results: The average Hausdorff distance was 0.36 mm between automatic and manual segmentations of the palatal stable region and was larger than the intraexaminer and interexaminer deviations. The tooth position deviation was <0.32 mm, and the tooth angulation difference was <0.26° for tip and torque, and 0.46-0.61° in rotation. ICCs, used for assessment of reliability, ranged from 0.82 to 0.99 in all variables.

Conclusions: The GCN-based MDM superimposition is an efficient method for the assessment of tooth movement in adults. The clinical error in tooth position and angulation induced by the method was clinically acceptable. Reliability was as high as manual segmentation.

Objectives: To determine acceptance of potential risks in orthodontic treatment and whether it could be affected by personality traits of patients.

Materials and methods: Two hundred sixty-one adult participants consulting for orthodontic treatment were involved in this cross-sectional study. Acceptance of 18 orthodontic risks was investigated with a structured questionnaire. Personality traits of included patients were assessed with a validated Chinese version of the Big Five Inventory. Statistical analyses were performed as appropriate, and potential correlations were identified using multivariate binary logistic regression analysis.

Results: Acceptability of the investigated orthodontic risks ranged from 47.1% to 87.0%, with periodontitis being the least accepted. Length of treatment (P = .015) and relapse (P = .007) were more unacceptable to older patients. Female participants showed less tolerance to periodontitis (P = .017) than male counterparts. Among the five dimensions of personality traits, conscientiousness was significantly associated with acceptance of tooth extraction and associated risks (odds ratio [OR] = 1.131, P = .002), problems eating (OR = 1.182, P < .001), problems speaking (OR = 1.111, P = .022), and appliance breakage (OR = 1.109, P = .008), while openness was a significant predictor to the acceptance of length of treatment (OR = 1.090, P = .044).

Conclusions: Among patients seeking orthodontic treatment, periodontitis was the least accepted risk. A significant association was found between the acceptance of certain orthodontic risks and personality traits, especially conscientiousness and openness.

Objectives: To determine factors associated with treatment duration in impacted maxillary canines (IMCs) using orthopantomography and cone beam computed tomography.

Materials and methods: Seventeen linear and angular measurements were evaluated using pretreatment radiographic images of 64 patients (83 IMCs). Treatment duration from surgical exposure until the canine appeared in the oral cavity and until achieving ideal alignment were recorded in months.

Results: Average treatment duration until appearance in the mouth was 14.61 ± 9.28 months and 26.98 ± 12.44 months until ideal alignment. Buccally impacted canines emerged in 6.56 ± 3.24 months and were ideally aligned in 19.44 ± 8.49 months in comparison with palatally positioned at 16.34 ± 9.19 and 28.91 ± 12.77 months, respectively. Canines localized around lateral incisors had shorter treatment times than those localized around central incisors. Canines that were inclined >30° to the sagittal medial line (SML) had significantly longer treatment time until initial appearance in the mouth (16.31 ± 9.32) compared with those inclined less (10.82 ± 8.92). Linear regression analyses demonstrated that these factors were predictors for both treatment duration until emergence and ideal alignment of the canine.

Conclusions: Treatment duration for IMCs is lengthy, particularly for palatally and mesially positioned canines and those with greater inclinations. Palatally located canines typically require twice as much time to emerge as those positioned buccally. Canines located nearer the central incisor area take twice as much time to emerge as those located in the lateral incisor area.

Objectives: To investigate the possible association between the presence of extreme premolar rotations (135° to 180° rotated premolars) and other dental anomalies within the dental anomaly pattern (DAP).

Materials and methods: Thirty-two healthy subjects exhibiting at least one premolar rotated 135° to 180° were identified from the archives of a university orthodontic clinic. Inclusion criteria were: presence of a rotated premolar, availability of panoramic radiographs, dental study casts, and intraoral photographs. The concomitant occurrence of additional dental anomalies was evaluated based on the DAP, including tooth agenesis, infraocclusion of deciduous molars, peg-shaped lateral incisors, palatally-displaced canines and transpositions. Comparisons were made to a randomly selected control group (n = 96) without this anomaly, using chi-square statistics.

Results: The experimental group displayed a higher prevalence of dental anomalies compared to the control group. Forty-seven percent of patients in the experimental group exhibited dental agenesis, whereas only 8% of the control group had dental agenesis (P < .001). Infraocclusion of deciduous molars (22% vs 5%; P = .005) and canine impaction (16% vs 3%; P = .035) were also observed more frequently in patients in the experimental group.

Conclusions: These findings reveal significant associations between the presence of extreme premolar rotations and the occurrence of other dental anomalies, namely dental agenesis, infraocclusion of deciduous molars, and palatally-displaced canines. These observations suggest a shared genetic origin for these anomalies.

Objectives: To analyze, appraise, and synthesize papers in which authors have compared the effects of chemotherapeutic toothpaste (CTP) and regular toothpaste (RTP) on plaque scores (PSs), gingival scores (GSs), and bleeding scores (BSs) in orthodontic patients wearing fixed appliances (FAs).

Materials and methods: PubMed-MEDLINE, Cochrane-CENTRAL, and Embase databases were searched with predefined search terms until April 2024 for controlled or randomized controlled clinical trials aligning with the aim. In the eligible papers, risk of bias was evaluated, data of interest were extracted, and a descriptive analysis was performed. If possible, meta-analyses and subanalyses on specific factors were conducted. The quality of evidence and strength of the recommendation were rated.

Results: In our search and selection, we obtained five papers describing eight comparisons. Potential risk of bias was assessed as some concerns to high, and heterogeneity was considered substantial. Descriptive analysis revealed no significant difference in PS and BS, with an improvement in GS favoring CTP. Meta-analyses of the end scores showed CTP significantly reduced PS (standardized mean difference [SMD] = -0.26; 95% confidence interval [CI] = -0.52, -0.01; P = .04). However, no significant effects were observed on GS and BS. These findings were supported by the subanalyses on CTP with chlorhexidine (CHX; PS: mean difference [MD] = -5.12; 95% CI = -10.08, -0.15; P = .04). The quality of evidence was graded as very low, and strength of the recommendation was judged as very weak.

Conclusions: For orthodontic patients with FAs, very weak certainty exists in recommending CTP (eg, with CHX) over RTP for use with toothbrushing. CTP may have a very small effect on PS and a small effect on GS.

Objectives: To identify the rotational fulcrum (RF) and to evaluate the skeletal and dentoalveolar effects after rapid palatal expansion (RPE) with tooth-borne and tooth-bone-borne (MARPE) appliances.

Materials and methods: 31 patients were selected (MARPE group: n = 14, age 16.2 ± 2 years; hyrax group: n = 17, age 14.7 ± 0.8 years) with RPE indication and having cone-beam computed tomography before (T1) and after RPE (T2) and after 6 months of retention (T3).

Results: In the MARPE group, the RF was at or above the frontozygomatic suture (FZS), whereas in the hyrax group, it was at or below the FZS. The skeletal response rates were 70% (2°) and 33% (1.09°); alveolar response rates, 18% (0.52°) and 20% (0.68°); and dental response rates, 12% (0.35°) and 47% (1.54°) in the MARPE and hyrax groups, respectively, with a significant difference between groups in skeletal (P = .005) and dental (P < .001) regions. After retention, no significant difference was found between groups.

Conclusions: Although MARPE resulted in a higher RF in the coronal view, both techniques effectively corrected transverse discrepancies with similar stability. Considering the between-group differences in relation to skeletal and dentoalveolar response, MARPE should be used for cases in which minimal compensatory tooth movement is desired.