American Journal of Orthodontics and Dentofacial Orthopedics最新文献

Introduction: The objective of this study was to assess changes in respiratory patterns, craniofacial development, and head and neck and overall body posture in children who have undergone early adenoidectomy and those who have not.

Methods: This multidisciplinary study was conducted in collaboration with the Departments of Otolaryngology, Physical Therapy and Rehabilitation, and Orthodontics. Patients diagnosed with adenoid vegetation who did not undergo surgery (group 1: n = 31; mean age 7.90 ± 1.55 years) and those who underwent early surgery (group 2: n = 30; mean age 8.30 ± 1.39 years) were included. The control group (group 3: n = 30; mean age 8.30 ± 1.39 years) consisted of subjects with no pathology causing respiratory obstruction and normal nasal breathing. Lateral and posteroanterior cephalograms, dental casts, the Nasal Obstruction Symptom Evaluation scale, and peak nasal inspiratory flow measurements were used for evaluation. Postural analysis was conducted using 3-dimensional motion analysis with Kinect sensors. Statistical comparisons were performed among groups.

Results: A difference was found among groups in respiratory parameters, and correlation analysis showed that these parameters were consistent with each other (P <0.05). However, no difference was observed in posture measurements among the groups (P >0.05). Although statistically significant differences were found among groups in the skeletal, dental, and soft tissue cephalometric parameters, significant correlations were also found between intergonial, interzygomatic distance, and corpus lengths with the respiratory parameters (P <0.05). Although no significant correlation was observed between the dental cast analysis values and the respiratory parameters, there was a statistically significant difference in intercanine distance among groups (P <0.05).

Conclusions: Early adenoidectomy improves respiratory and craniofacial growth, resembling normal nasal breathing. Delayed surgery leads to persistent mouth-breathing and negative growth outcomes. Close collaboration between otolaryngologists and orthodontists is essential for optimal management.

Introduction: Adult orthodontic patients are often exposed to various stressors, which can affect orthodontic treatment. Therefore, this study investigated the effects of chronic restraint stress on orthodontic tooth movement and alveolar bone remodeling in vivo.

Methods: Ten 8-week-old male Wistar rats were randomly divided into sham-stress orthodontic (CO) and stress orthodontic (SO) groups. Restraint stress was applied for 21 days. The orthodontic intervention involved mesial traction of the maxillary first molar from days 8 to 21. Serum inflammatory cytokine levels were measured, and micro-computed tomography scanning was performed to analyze tooth movement and alveolar bone parameters of the first molar. Osteogenic and osteoclastic activities and macrophage polarization in periodontal tissues were assessed by histological and immunohistochemical staining.

Results: Tooth movement was significantly greater in the SO group than in the CO group, as were the serum interleukin-1β and -10 levels. The SO group had increased trabecular spacing, reduced bone density, and wider periodontal ligament spaces on the force-applied side of the alveolar bone. Enhanced osteogenic and osteoclastic activities were observed in both groups under orthodontic force, but significantly more osteoclasts were observed in the SO group than in the CO group. The inducible nitric oxide synthase to arginase 1 expression ratio was also significantly higher in the SO group than in the CO group.

Conclusions: Restraint stress may exacerbate orthodontic tooth movement and alveolar bone resorption, potentially mediated by systemic inflammatory responses, as well as enhance classically activated macrophage polarization in the alveolar bone.

Introduction: This study aimed to compare the 3-dimensional (3D) variability of mandibular morphology across different age groups and skeletal classes.

Methods: A retrospective analysis was conducted on cone-beam computed tomography scans from 282 patients aged 9-50 years. The participants were stratified into 6 age groups using random stratified sampling: group (G)1 (n = 51), G2 (n = 51), G3 (n = 52), G4 (n = 56), G5 (n = 41), and G6 (n = 31). Each patient was categorized according to the skeletal classification (I, II, and III). The 3D mandibular models were created using specialized software, with 32 anatomic landmarks placed on each model. Landmark configurations were aligned through generalized Procrustes analysis. Shape variation was evaluated using principal component analysis, permutational multivariate analysis of variance, and canonical variate analysis, followed by pairwise comparisons.

Results: Significant differences in mandibular shape were found among age groups, especially in younger patients, whereas skeletal class showed no significant effect. The most notable differences were observed in canonical variables 1 and 2, particularly between younger groups (G1 and G2) and older groups (P <0.001). These differences involved changes in the basal mandibular contour, bicondylar width, and bigonial width. Skeletal class had no significant impact on mandibular morphology.

Conclusions: The 3D modeling revealed significant age-related changes in mandibular basal contour, transverse expansion, chin projection, ramus height and thickness, gonial angle, and anterior body curvature. This highlights the value of 3D models for precise analysis of changes in mandibular shape across ages.

Introduction: Cleidocranial dysplasia (CCD) often results in supernumerary teeth, impacted teeth, and malocclusions. Treatment options include orthodontics to erupt the impacted dentition in the oral cavity or prosthodontic replacement of impacted teeth. This study assesses whether patients with CCD who have certain malocclusion traits have worse oral health-related quality of life (OHRQoL) than those without these malocclusions, and whether patients with CCD who received orthodontic treatment have better OHRQoL than those treated with prosthodontics.

Methods: Patients with CCD aged 15 years and older underwent an oral examination and completed the oral health impact profile-14 survey. Independent-samples t tests were performed to compare the oral health impact profile-14 scores among patients with and without specific oral findings.

Results: Sixty-one patients participated in this study. Those with posterior crossbites experienced significantly worse OHRQoL in the domain of physical pain (P = 0.015; 95% confidence interval [CI] = 0.316-2.750). For those with anterior open bites, a significantly worse OHRQoL was observed in the domain of handicap (P = 0.046; 95% CI, 0.027-2.919). Anterior crossbites resulted in statistically significantly worse OHRQoL in the functional limitation domain (P = 0.027; 95% CI, 0.149-2.373). Lastly, patients who received prosthodontic treatment reported significantly worse OHRQoL (P = 0.037; 95% CI, 0.685-21.015) and higher scores in physical pain (P = 0.038; 95% CI, 0.114-3.981), physical disability (P = 0.005; 95% CI, 0.872-4.543), and social disability (P = 0.020; 95% CI, 0.091-3.398).

Conclusions: Patients with CCD who have anterior crossbites, posterior crossbites, or anterior open bites have worse OHRQoL in specific domains compared with those without these malocclusions. In addition, patients who underwent prosthodontics had worse OHRQoL than those who underwent orthodontics.

Introduction: This study develops a finite element analysis method to define the 3-dimensional (3D) zone of center of resistance (ZCR) position for maxillary central incisors and first molars and validates its applicability under different alveolar bone levels.

Methods: Cone-beam computed tomography scans from 40 patients were grouped: group 1 (maxillary central incisors, no bone loss), group 2 (maxillary central incisors, bone loss), group 3 (maxillary first molars, no bone loss), and group 4 (maxillary first molars, bone loss). The 3D models of teeth, a simulated 0.2-mm-thick PDL, and alveolar bone were reconstructed using Mimics software (Materialise, Leuven, Belgium) and imported into ANSYS Workbench (ANSYS Inc, Canonsburg, Pa) to calculate the tooth axis of rotation (resistance axis). A 5-step method defined the ZCR: (1) set the crown center as origin, (2) apply pure 3 N·mm couples at the crown center along the x-, y-, and z-axes, (3) find the resistance axes using displacement data, (4) use an algorithm to find best point filtering (1%-3%) where axes meet; fit a sphere to these points to get the ZCR center and radius, and (5) verify the accuracy by measuring rotation angles after applying forces at the center of the ZCR, and the 1 and 2 times radius in the 3 directions.

Results: Optimal filtering percentages averaged 2.23% (group 1), 2.10% (group 2), 1.33% (group 3), and 1.63% (group 4). Alveolar resorption reduced the ZCR height. The central incisors decreased from 59.17% (standard deviation [SD]: 1.01) to 45.19% (SD: 1.61), whereas first molars decreased from 53.76% (SD: 3.03) to 46.76% (SD: 2.02) of root length. The ZCR radius decreased with alveolar bone loss-central incisors (from 0.55 to 0.49 mm) and first molars (from 0.58 to 0.48 mm). Forces applied at the center of the ZCR minimized rotation angles (x/y-axis: 0.12°; z-axis: 0.09°). Rotation increased significantly when forces were applied beyond the sphere, reaching 1.92° at twice the radius.

Conclusions: The finite element analysis method accurately and efficiently defined the 3D ZCR position and extent in central incisors and first molars. Alveolar bone loss induced apical displacement and a reduction in the ZCR extent.

Introduction: This study aimed to evaluate and compare the palatal dimensional and morphologic characteristics (symmetry or asymmetry) before and after the treatment of functional posterior crossbite (FPXB) in mixed and permanent dentition.

Methods: Forty-four patients with a diagnosis of transverse maxillary deficiency and FPXB underwent maxillary expansion: 22 in mixed dentition (mixed dentition study group [MD-SG], mean age = 8.6 ± 1.3 years) and 22 in permanent dentition (permanent dentition study group [PD-SG], mean age = 13.3 ± 1.1 years). Two age-matched control groups (mixed dentition control group and permanent dentition control group) were included. Digital models at T0 (baseline) and T1 (12-18 months postexpansion) were analyzed for palatal dimensions, volume, and symmetry. Deviation analysis and percentage matching were performed between the original and the mirrored models. Statistical analyses assessed intragroup, intergroup, and intertiming differences.

Results: At T0, linear and volumetric measurements were greater at the noncrossbite side (nCBs) than the crossbite side (CBs) in patients with FPXB compared with controls (P <0.001). The CBs/nCBs volumetric difference was greater in PD-SG than MD-SG (P = 0.001), whereas surface matching was higher in MD-SG (P = 0.004). At T1, CBs/nCBs dimensional asymmetry decreased in both FPXB groups (P <0.001), and the surface matching improved (P <0.001). However, MD-SG remarkably showed greater posttreatment changes than PD-SG (volumetric data: P = 0.012; surface data: P = 0.009).

Conclusions: Patients with FPXB in permanent dentition could exhibit greater maxillary asymmetry than in mixed dentition. After reestablishment of normal occlusion, the asymmetry reduced in both MD-SG and PD-SG, though the latter group retained more residual asymmetry, potentially affecting final maxillary morphology.

Introduction: The purpose of this study was to quantitatively evaluate the infrazygomatic bone parameters (buccal bone thickness and buccal bone height) for miniscrew placement. An additional aim was to compare and contrast the infrazygomatic bone parameters in growing and nongrowing males and females with hyperdivergent, normodivergent, and hypodivergent skeletal patterns.

Methods: Cone-beam computed tomography scans were obtained from 718 deidentified orthodontic patients and categorized by growth status (growing and nongrowing), sex (male and female), and skeletal pattern (hyperdivergent, hypodivergent, and normodivergent). Buccal bone thickness and buccal bone height were measured at 3 locations: 2P-1M (between the maxillary second premolar and first molar), 1M (between the mesial and distal roots of the maxillary first molar), and 1M-2M (between the maxillary first and second molars) and at 3 levels above base plane (BP): 5BP, 8BP, and 11BP, which were 5, 8, and 11 mm above the alveolar crest, respectively.

Results: Males had significantly greater buccal bone thickness than females at 5BP and 8BP (P <0.05). Males also had greater buccal bone height than females at the 1M-2M location. Buccal bone thickness increased, and buccal bone height decreased significantly as it moved posteriorly from the 2P-1M location to the 1M-2M location. Buccal bone thickness was higher in growing females and males than in nongrowing females and males. Multiple linear regression demonstrated a significant relationship between buccal bone thickness and the prediction variables: skeletal pattern and sex. Buccal bone thickness was greater in the hypodivergent skeletal pattern than in the hyperdivergent skeletal pattern at the level of 8BP in the location of 2P-1M and at the level of 11BP in the locations of 2P-1M and 1M. Buccal bone height was greater in the hyperdivergent skeletal pattern at the 2P-1M and 1M locations than in the hypodivergent and normodivergent skeletal patterns.

Conclusions: Because of adequate buccal bone thickness and acceptable buccal bone height, the 1M-2M location was considered the optimal insertion site for the placement of infrazygomatic miniscrews. Patients with a hyperdivergent skeletal pattern showed reduced buccal bone thickness and increased buccal bone height. Buccal bone thickness was significantly greater in males than in females in all skeletal patterns.