Korean Journal of Orthodontics最新文献

Objective: To assess the success rate and proximity of miniscrews to the root using surgical guides produced by integrating data obtained from cone-beam computed tomography and intraoral scanned models.

Methods: This retrospective study involved 113 patients (224 miniscrews) who underwent miniscrew placement as part of their orthodontic treatment. Two operators placed miniscrews between the buccal alveolar bone of each patient and assessed initial stability by measuring the Periotest value (PTV) and insertion torque (IT). Patients were divided into two groups based on the miniscrew insertion method: manual group (MG) and surgical guide group (SG). Root proximity was assessed using periapical radiography, and miniscrews that remained in place for over 6 months were considered successful.

Results: There was a statistically significant difference in the Kaplan-Meier survival curves between the groups (P < 0.05). The success rates of the miniscrews were 79.1% and 90.5% for the MG and SG, respectively (P < 0.05). The root contact rate also differed significantly between the groups (MG, 17.5%; SG, 0.1%; P < 0.001). However, the PTV and IT did not show significant differences between the groups.

Conclusions: Proximity to the root and utilization of surgical guides have the most direct impact on the success rate of miniscrews. Root proximity can be effectively reduced using surgical guides. Therefore, the use of a miniscrew surgical guide is recommended to increase the success rate of miniscrews as stable anchorage devices, particularly in cases with narrow interradicular space.

Objective: Temporary anchorage devices (TADs) have considerably reduced the need for anterior segmental osteotomy (ASO) in patients with Class I malocclusion. Most previous studies have been published before the widespread use of TADs, thus warranting new guidelines for determining the optimal approach for surgery and orthodontic treatment. This study aimed to establish guidelines on the choice between ASO and non-ASO (NASO) based on soft tissue considerations.

Methods: Sixty-seven patients diagnosed with skeletal Class II malocclusion were divided into the ASO (n = 31) and NASO (n = 36) groups. Cephalometric analyses were used to compare the initial and final records to assess the effect of treatment on soft tissues. The interlabial gap, upper lip anterior to the E-line, lower lip anterior to the E-line, H-angle, upper lip to the nasion-perpendicular line, and nasolabial angle were evaluated. In particular, a proportional difference indicator between the upper and lower lips relative to the pogonion angle between the facial plane and CK line was presented, followed by statistics analyses. Statistical significance was set at P < 0.05.

Results: Both groups demonstrated normal proportions of the upper and lower lips; however, significant differences favoring ASO over NASO in terms of soft tissue changes were observed for several variables.

Conclusions: ASO is advised if the required adjustment for the upper and lower lips is -4.0 mm and -5.0 mm, respectively. For modifications of -2.0 mm, NASO is preferred. This study provides clinical guidelines on the choice between ASO and NASO based on the required lip movement measurements.

Objective: To evaluate the effects of rapid maxillary expansion (RME) on nasal patency and nasomaxillary dimensions in children and adolescents with mouthbreathing through 8 years of clinical follow-up.

Methods: RME was performed using a Hyrax orthodontic appliance in 28 mouth-breathers (6-13 years old). During follow-up, objective tests of nasal respiratory function were conducted, such as acoustic rhinometry, which provided the minimum cross-sectional areas of the nasal cavity, and active anterior computed rhinomanometry, which measured inspiratory nasal resistance. The tomographic widths of the coronal sections of the nose and maxilla were also measured. Fisher's exact test and the Mann-Whitney U test were used to compare categorical and numerical variables, respectively, in mouth-breathers with and without allergic rhinitis. Temporal evolution was assessed using generalized estimating equation models. Statistical significance was set at P < 0.05.

Results: There was a reduction in inspiratory resistance after RME with a stable improvement in nasal patency during the 8-year follow-up period (P = 0.0179). All nasal and maxillary tomographic widths showed statistically significant increases in the short-term (P < 0.0001), and most of them showed significant increases in the long-term when compared with the pre-expansion period. Tomographic measurements were not influenced by allergic rhinitis.

Conclusions: Our study showed that RME promoted and maintained the widening of the posterior maxillary structure in children and adolescents with mouth-breathing, with a decrease in inspiratory nasal resistance during the 8-year follow-up period. These findings highlight the importance of RME in mouth-breathers with maxillary atresia.

Objective: Orthodontic appliances are commonly used to achieve anchorage during orthodontic treatments; however, their use can contribute to oral diseases. Studies have shown that bisphosphonates and osteoprotegerin are highly effective in reducing orthodontic tooth movement. To determine the efficacy of bisphosphonates and osteoprotegerin in reducing orthodontic tooth movement.

Methods: A comprehensive search was conducted across five databases-MEDLINE-PubMed, Scopus, Google Scholar, ScienceDirect, and Taylor & Francis-up to August 2, 2023. Clinical trials conducted in healthy animals, where bisphosphonates and osteoprotegerin were administered during tooth movement, were included. The search identified 3,099 articles, which underwent a two-phase screening process, resulting in twelve studies for the systematic review and seven for the meta-analysis. Risk of bias was assessed using the SYRCLE tool, and Egger's regression was used to evaluate publication bias.

Results: The administration of bisphosphonates was more effective than osteoprotegerin in reducing mesiodistal orthodontic movement. However, osteoprotegerin did not significantly reduce orthodontic tooth movement.

Conclusions: The findings align with previous studies, confirming the superior efficacy of bisphosphonates over osteoprotegerin. Further research is required to determine the optimal dosage and mechanism of action for these drugs in clinical practice, considering the specific objectives of orthodontic treatments.

Objective: This prospective study evaluated the effectiveness of clear aligner treatment (CAT) in achieving dentoalveolar upper arch expansion in patients with mixed dentition and transverse maxillary deficiency.

Methods: Forty patients with mixed dentition and a transverse discrepancy of ≤ 5 mm were treated using clear aligners. Pre- and post-treatment digital dental models were measured using specific landmarks and compared with the programmed expansion in the virtual treatment plan. Statistical analyses included the inter-class correlation coefficient to evaluate inter-rater reliability. A paired t test was employed to compare pre- and post-treatment values and to examine the significance of the changes. Multiple regression analysis was conducted to estimate the relationship between the prescribed and observed measurements, stratified by inter-dental measurements (deciduous canines, first deciduous molars, and permanent molars, at cusp and gingival levels).

Results: Excellent measurement reproducibility was observed. The accuracy of dentoalveolar maxillary arch expansion varied among different tooth regions. The inter-canine accuracy was 87.7% at the cusp level and 82.7% at the gingival level. The inter-first deciduous molars exhibited accuracies of 84.9% (cusp level) and 80.5% (gingival level). The inter-first molars showed accuracies of 77.8% (cusp level) and 67.9% (gingival level). Significant differences were observed between the planned and obtained measurements for specific tooth regions.

Conclusions: CAT demonstrated reliable predictability in achieving dentoalveolar expansion of the maxillary arch in patients with mixed dentition. A higher accuracy was observed in the anterior region than in the posterior region. These findings suggest that CAT could be an effective option for treating transverse maxillary deficiencies in patients with mixed dentition with moderate inter-arch transverse discrepancies, considering tooth-specific predictability differences.

Objective: Extraction of the mandibular second molar (L7) and substitution by the mandibular third molar (L8) is an effective treatment option. This study aimed to evaluate spontaneously erupted L8 occlusion after L7 extraction, and identify the influencing factors.

Methods: This study assessed 46 L8 from 28 patients using dental study models, panoramic radiographs, and lateral cephalograms obtained during L7 extraction (T1) and completion of L8 eruption (T2). At T2, samples were categorized as acceptable (A-group) or unacceptable (U-group) based on the American Board of Orthodontics index. L8 angulation and position, retromolar space, distance between the Xi point and mandibular first molar (L6), and Nolla stage were compared between the groups to identify the predictive factors for successful eruption.

Results: At T2, 58.7% of L8 exhibited acceptable occlusion. Age at T1 was significantly higher in the U-group than that in the A-group. Angles ∟6-MnP and ∟8-MnP differed significantly between the groups at T2. Xi-L6 distance was considerably longer in the A-group than that in the U-group at T1 and T2. Younger age at extraction and Xi-L6 distance at T1 affected the acceptable occlusion.

Conclusions: Younger age at L7 extraction and adequate eruption space (Xi-L6 distance) appear to be the key factors for achieving acceptable L8 occlusion.

Objective: The treatment of asymmetric maxillary hypoplasia and dental crowding secondary to unilateral cleft lip and palate (UCLP) is often challenging. This study introduced an asymmetric tooth-borne distractor in anterior maxillary segmental distraction osteogenesis and used three-dimensional finite element analysis to evaluate its potential for clinical application in cases of asymmetrical maxillary hypoplasia.

Methods: A cone-beam computed tomography scan of a late adolescent with UCLP was used to construct a three-dimensional finite element model of the teeth and maxillary structures. An asymmetric distractor model was used to simulate conventional distraction osteogenesis and asymmetric distraction osteogenesis (ADO) to evaluate the resultant stress distribution and displacement.

Results: Postoperatively, both distraction methods resulted in anterior maxillary segment advancement with a slight upward movement. ADO yielded a greater increase in the dental arch length on the cleft side and induced rotation of the anterior maxillary segment, potentially improving midline deviation. Both methods showed similar stress distributions, with higher stress concentrations on the cleft side.

Conclusions: ADO may offer clinical advantages in correcting asymmetrical maxillary hypoplasia in patients with UCLP by facilitating asymmetrical expansion and rotation of the maxilla. Further research is needed to generalize these findings to other clinical presentations.

Objective: This study aimed to evaluate the reliability and usefulness of information generated by Chat Generative Pre-Trained Transformer (ChatGPT) on temporomandibular joint disorders (TMD).

Methods: We asked ChatGPT about the diseases specified in the TMD classification and scored the responses using Likert reliability and usefulness scales, the modified DISCERN (mDISCERN) scale, and the Global Quality Scale (GQS).

Results: The highest Likert scores for both reliability and usefulness were for masticatory muscle disorders (mean ± standard deviation [SD]: 6.0 ± 0), and the lowest scores were for inflammatory disorders of the temporomandibular joint (mean ± SD: 4.3 ± 0.6 for reliability, 4.0 ± 0 for usefulness). The median Likert reliability score indicates that the responses are highly reliable. The median Likert usefulness score was 5 (4-6), indicating that the responses were moderately useful. A comparative analysis was performed, and no statistically significant differences were found in any subject for either reliability or usefulness (P = 0.083-1.000). The median mDISCERN score was 4 (3-5) for the two raters. A statistically significant difference was observed in the mean mDISCERN scores between the two raters (P = 0.046). The GQS scores indicated a moderate to high quality (mean ± SD: 3.8 ± 0.8 for rater 1, 4.0 ± 0.5 for rater 2). No statistically significant correlation was found between mDISCERN and GQS scores (r = -0.006, P = 0.980).

Conclusions: Although ChatGPT-4 has significant potential, it can be used as an additional source of information regarding TMD for patients and clinicians.

Objective: This study aimed to evaluate the changes in upper airway (UA) dimensions in growing patients with Pierre-Robin sequence (PRS).

Methods: The subjects were 23 PRS patients who had not undergone growth modification therapy or surgical intervention. Their lateral cephalograms were obtained longitudinally at mean ages of 8.81 (T0) and 14.05 (T1). Patients were categorized based on their SNB value at T0 (Criteria: -2 SD): Group-1 (very retrusive mandible, n = 13) and Group-2 (moderately retrusive mandible, n = 10). Skeletal and UA variables at T0 and T1, as well as ΔT0-T1, were statistically analyzed.

Results: At T0, Group-1 exhibited more retrusive maxilla and mandible (SNA, P < 0.01; SNB, P < 0.001), a more hyperdivergent pattern (facial height ratio, P < 0.05), and a more posteriorly positioned hyoid bone (H-PTV, P < 0.05), while Group-1 showed larger UA spaces (superior pharyngeal airway space [SPAS] and inferior pharyngeal airway space, all P < 0.05) than Group 2, which might indicate the existence of a compensatory response to maintain the UA patency. At T1, Group-1 maintained significantly retrusive maxilla and mandible (SNA and SNB, all P < 0.01), exhibited a less anteriorly positioned tongue (TT-PTV, P < 0.05), and displayed a more obtuse soft palate angle (SPA, P < 0.05) than Group-2. Between T0 and T1, Group-1 demonstrated significant increases in the hyoid symphysis distance (ΔH-RGN, P < 0.001), tongue length (ΔTGL, P < 0.01), and pharyngeal UA spaces (ΔSPAS and ΔPNS-ad2, all P < 0.001).

Conclusions: Even in growing PRS patients with severe mandibular retrusion, the UA dimensions increased due to forward growth of the mandible, repositioning of tongue and hyoid bone, and existence of compensatory mechanism.

Objective: This study aimed to compare the accuracy of Qlone, Magiscan, and 3dMD with that of direct anthropometry (DA).

Methods: The study involved 41 patients. Sixteen facial landmarks, including six individual and five paired points, were marked on each participant's face. Subsequently, 18 linear measurements were assessed using a 3dMD device (multicamera photogrammetry), Qlone, Magiscan smartphone applications (single-camera photogrammetry), and DA. The Qlone and Magiscan images were calibrated using a reference point 10 mm from the nasion during DA to ensure a 1:1 correspondence.

Results: Concerning the precision of the digital methods compared to DA, the mean intraclass correlation coefficient values of 3dMD, Qlone and Magiscan were 0.989, 0.980 and 0.982, respectively. Compared with DA, 3dMD achieved excellent trueness with the lowest average absolute differences in the measurements (highest value = 0.95 ± 0.62 mm). The highest values for Qlone and Magiscan were 1.51 ± 1.11 mm and 2.14 ± 1.69 mm, respectively. According to the number of parameters, the ranking of unreliable values (> 2 mm) was Magiscan (n = 46), Qlone (n = 35), and then, 3dMD (n = 4). Furthermore, reliability (less than 1 mm) was the highest for 3dMD (n = 517), followed by Magiscan (n = 457), and then, Qlone (n = 415).

Conclusions: The 3dMD achieved excellent trueness with the lowest average absolute differences in the measurements. Based on statistical analysis, the trueness values of Magiscan and Qlone were close to that of 3dMD. To apply these smartphone applications clinically, more studies are necessary.