The Angle orthodontist最新文献

Objective: To investigate the effectiveness of early and short-term administration of lithium (Li) during orthodontic force application (OFA) in preventing orthodontically induced root resorption (OIRR) and verify the importance of the early phase of OFA in the induction of OIRR.

Materials and methods: Bilateral maxillary first molars of 10-week-old male Wistar rats were moved for 14 days using a closed coil spring inserted between the first molar and the incisor. The rats were randomly grouped into three groups: a group receiving Li for the first 4 days, a group receiving Li daily for 14 days, and a control group receiving a vehicle (saline). Orthodontic tooth movement (OTM) was measured using microcomputed tomography on day 14. The OIRR, osteoclasts, and odontoclasts were evaluated via histological analysis. Immunohistochemical staining for the receptor-activated NF-kB ligand and osteoprotegerin was also performed.

Results: The OTM distance did not differ among the three groups, and the pattern of OTM changed from tipping to bodily movement for both Li groups. Early and short-term administration of Li suppressed OIRR on day 14 as effectively as long-term administration for 14 days. The observed odontoclasts on days 4 and 14 were significantly reduced in both Li groups. Osteoprotegerin expression was significantly increased on day 14 in both groups receiving Li relative to the vehicle group.

Conclusions: Early and short-term Li administration effectively suppressed OIRR. This suggests that the early phase of OFA plays an important role in the induction of OIRR.

Objectives: To investigate the predictors of willingness to uptake orthodontic treatment and to explore the reasons for postponing its initiation in young adults.

Materials and methods: Students, aged 18-30 years old, were randomly approached at the Central Library of the Aristotle University of Thessaloniki Campus and invited to complete the study tool anonymously and voluntarily. The Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) and the esthetic component of the Index of Orthodontic Treatment Need (IOTN-AC) were used to evaluate students' psychosocial impact of dental esthetics and severity of malocclusion, whereas the rationale for postponing the initiation of orthodontic treatment was recorded through an open-ended question, analyzed using thematic content analysis.

Results: In total, 270 students, 55.2% female, participated. The single statistically significant factor predicting willingness to uptake orthodontic treatment was the PIDAQ-Psychological Impact subscale (OR: 1.24; 95% CI: 1.11-1.37, P < .001). Gender and age were not associated with willingness to pursue treatment. Seven main themes emerged regarding reasons for postponement: fear of the procedure, embarrassment regarding appearance during treatment, low prioritization of esthetics, insufficient information, high cost of treatment, prolonged duration of treatment, and residential mobility.

Conclusions: The findings suggest that psychological impact of dental esthetics constitutes the main driver to pursue orthodontic treatment. A patient-centered orthodontic approach should address the possible barriers to its initiation. Increasing young adults' oral health literacy could be key in empowering them to make better informed decisions regarding their oral health-related quality of life.

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.