Posterior dental compensation and occlusal function in adults with different sagittal skeletal malocclusions / 대한치과교정학회지

OBJECTIVE@#The aim of this study was to compare posterior tooth inclinations, occlusal force, and contact area of adults with different sagittal malocclusions.@*METHODS@#Transverse skeletal parameters and posterior tooth inclinations were evaluated using cone beam computed tomography images, and occlusal force as well as contact area were assessed using pressure-sensitive films in 124 normodivergent adults. A linear mixed model was used to cluster posterior teeth into maxillary premolar, maxillary molar, mandibular premolar, and mandibular molar groups. Differences among Class I, II, and III groups were compared using an analysis of variance test and least significant difference post-hoc test. Correlations of posterior dental inclinations to occlusal function were analyzed using Pearson's correlation analysis.@*RESULTS@#In male subjects, maxillary premolars and molars had the smallest inclinations in the Class II group while maxillary molars had the greatest inclinations in the Class III group. In female subjects, maxillary molars had the smallest inclinations in the Class II group, while maxillary premolars and molars had the greatest inclinations in the Class III group. Occlusal force and contact area were not significantly different among Class I, II, and III groups.@*CONCLUSIONS@#Premolar and molar inclinations showed compensatory inclinations to overcome anteroposterior skeletal discrepancy in the Class II and III groups; however, their occlusal force and contact area were similar to those of Class I group. In subjects with normodivergent facial patterns, although posterior tooth inclinations may vary, difference in occlusal function may be clinically insignificant in adults with Class I, II, and III malocclusions.

The effect of cetirizine, a histamine 1 receptor antagonist, on bone remodeling after calvarial suture expansion / 대한치과교정학회지

OBJECTIVE@#The objective of this study was to evaluate the effects of cetirizine, a histamine 1 receptor antagonist, on bone remodeling after calvarial suture expansion.@*METHODS@#Sixty male Sprague–Dawley rats were divided into 4 groups; the phosphate-buffered saline (PBS)-injected no expansion group, cetirizine-injected no expansion group, PBS-injected expansion group, and cetirizine-injected expansion group, and were observed at 7, 14, and 28 days. Five rats per group were examined at each observation day. Daily injections of cetirizine or PBS were administered to the relevant groups starting 2 weeks prior to expander insertion. A rapid expander was inserted in the calvarial bone to deliver 100 cN of force to the parietal suture. The specimens were prepared for hematoxylin and eosin and tartrate-resistant acid phosphatase (TRAP) staining. Suture opening and bone regeneration were evaluated using microcomputed tomography and bone histomorphometric analysis. Serum blood levels of osteocalcin and carboxy-terminal collagen crosslinks (CTX) were also evaluated.@*RESULTS@#TRAP-positive cell counts and CTX levels decreased while osteocalcin levels increased in the cetirizine-injected expansion group at observation day 28. In the expansion groups, the mineralized area gradually increased throughout the observation period. At day 28, the cetirizine-injected expansion group showed greater bone volume density, greater mineralized area, and narrower average suture width than did the PBS-injected expansion group.@*CONCLUSIONS@#Cetirizine injection facilitated bone formation after suture expansion, mostly by suppressing osteoclastic activity. Histamine 1 receptor antagonists may aid in bone formation after calvarial suture expansion in the rat model.

Assessment of lower incisor alveolar bone width using cone-beam computed tomography images in skeletal Class III adults of different vertical patterns / 대한치과교정학회지

OBJECTIVE: This study was performed to investigate the alveolar bone of lower incisors in skeletal Class III adults of different vertical facial patterns and to compare it with that of Class I adults using cone-beam computed tomography (CBCT) images. METHODS: CBCT images of 90 skeletal Class III and 29 Class I patients were evaluated. Class III subjects were divided by mandibular plane angle: high (SN-MP > 38.0°), normal (30.0°< SN-MP < 37.0°), and low (SN-MP < 28.0°) groups. Buccolingual alveolar bone thickness was measured using CBCT images of mandibular incisors at alveolar crest and 3, 6, and 9 mm apical levels. Linear mixed model, Bonferroni post-hoc test, and Pearson correlation analysis were used for statistical significance. RESULTS: Buccolingual alveolar bone in Class III high, normal and low angle subjects was not significantly different at alveolar crest and 3 mm apical level while lingual bone was thicker at 6 and 9 mm apical levels than on buccal side. Class III high angle group had thinner alveolar bone at all levels except at buccal alveolar crest and 9 mm apical level on lingual side compared to the Class I group. Class III high angle group showed thinner alveolar bone than the Class III normal or low angle groups in most regions. Mandibular plane angle showed negative correlations with mandibular anterior alveolar bone thickness. CONCLUSIONS: Skeletal Class III subjects with high mandibular plane angles showed thinner mandibular alveolar bone in most areas compared to normal or low angle subjects. Mandibular plane angle was negatively correlated with buccolingual alveolar bone thickness.

Total intrusion and distalization of the maxillary arch to improve smile esthetics / 대한치과교정학회지

This case report illustrates the successful treatment of a patient with skeletal Class II malocclusion and an unesthetic smile involving excessive gingival display and large buccal corridors. By applying dual buccal interradicular miniscrews, total intrusion of the maxillary dentition along with distalization was induced to improve both the occlusion and smile esthetics. In addition to the conventional cephalometric superimposition, three-dimensional superimposition was performed and evaluated to validate the treatment outcome.

Long-term survival of retained deciduous mandibular second molars and maxillary canine incorporated into final occlusion / 대한치과교정학회지

Orthodontic treatment of a complex case that involves retained deciduous mandibular second molars with missing permanent successors is challenging. Usually, congenitally missing teeth are manifested with other dental anomalies that further complicate orthodontic treatment, such as retained deciduous teeth, impactions, transpositions and peg-shaped lateral incisors. Even though the long term prognosis of the retained deciduous tooth is not fully predictable, if the teeth are in good condition, the patient and clinician may incline towards a decision to preserve the deciduous teeth as long as possible. This case report demonstrates that deciduous teeth, in this case the mandibular second molars and maxillary canine, can be incorporated into final occlusion with clinically stable long-term results.

Immune Tolerance of Human Dental Pulp-Derived Mesenchymal Stem Cells Mediated by CD4⁺CD25⁺FoxP3⁺ Regulatory T-Cells and Induced by TGF-β1 and IL-10

PURPOSE: Most studies on immune tolerance of mesenchymal stem cells (MSCs) have been performed using MSCs derived from bone marrow, cord blood, or adipose tissue. MSCs also exist in the craniofacial area, specifically in teeth. The purpose of this study was to evaluate the mechanisms of immune tolerance of dental pulp-derived MSC (DP-MSC) in vitro and in vivo. MATERIALS AND METHODS: We isolated DP-MSCs from human dental pulp and co-cultured them with CD4⁺ T-cells. To evaluate the role of cytokines, we blocked TGF-β and IL-10, separately and together, in co-cultured DP-MSCs and CD4⁺ T-cells. We analyzed CD25 and FoxP3 to identify regulatory T-cells (Tregs) by fluorescence-activated cell sorting (FACS) and real-time PCR. We performed alloskin grafts with and without DP-MSC injection in mice. We performed mixed lymphocyte reactions (MLRs) to check immune tolerance. RESULTS: Co-culture of CD4⁺ T-cells with DP-MSCs increased the number of CD4⁺CD25⁺FoxP3⁺ Tregs (p<0.01). TGF-β or/and IL-10 blocking suppressed Treg induction in co-cultured cells (p<0.05). TGF-β1 mRNA levels were higher in co-cultured DP-MSCs and in co-cultured CD4⁺ T-cells than in the respective monocultured cells. However, IL-10 mRNA levels were not different. There was no difference in alloskin graft survival rate and area between the DP-MSC injection group and the non-injection group. Nonetheless, MLR was reduced in the DP-MSC injected group (p<0.05). CONCLUSION: DP-MSCs can modulate immune tolerance by increasing CD4⁺CD25⁺FoxP3⁺ Tregs. TGF-β1 and IL-10 are factors in the immune-tolerance mechanism. Pure DP-MSC therapy may not be an effective treatment for rejection, although it may module immune tolerance in vivo.

Scar formation and revision after the removal of orthodontic miniscrews / 대한치과교정학회지

Many clinicians expect complete healing after the removal of temporary anchorage devices, but clinical examination may reveal scar-like tissue. This report presents the typical features of scarring detected after the removal of miniscrews, and the clinical outcome of scar revision along with its pathologic features.

Long-term pharyngeal airway changes after bionator treatment in adolescents with skeletal Class II malocclusions / 대한치과교정학회지

OBJECTIVE: The aim of this study was to evaluate long-term changes in the pharyngeal airway dimensions after functional appliance treatment in adolescents with skeletal Class II malocclusions. METHODS: Pharyngeal airway dimensions were compared between subjects with skeletal Class II malocclusions (n = 24; mean age: 11.6 +/- 1.29 years) treated with a Class II bionator and age-matched control subjects with skeletal Class I occlusions (n = 24; mean age: 11.0 +/- 1.21 years) using a series of lateral cephalograms obtained at the initial visit (T0), after treatment (T1), and at the completion of growth (T2). RESULTS: The length of the nasopharyngeal region was similar between adolescents with skeletal Class I and Class II malocclusions at all time points, while the lengths of the upper and lower oropharyngeal regions and the pharyngeal airway areas were significantly smaller in the skeletal Class II adolescents before treatment when compared to the control adolescents (p < 0.05). However, following treatment with a functional appliance, the skeletal Class II adolescents had increased pharyngeal airway dimensions, which became similar to those of the control subjects. CONCLUSIONS: Functional appliance therapy can increase the pharyngeal airway dimensions in growing adolescents with skeletal Class II malocclusions, and this effect is maintained until the completion of growth.

Changes in occlusal force and occlusal contact area after orthodontic treatment / 대한치과교정학회지

OBJECTIVE: This study was performed to evaluate functional changes of occlusion after orthodontic treatment by measuring the occlusal force (OcFr) and occlusal contact area (OcAr), and to compare OcFr and OcAr change according to premolar extractions. METHODS: Data were obtained from 74 patients who had finished orthodontic treatment using fixed appliance aged between 18 and 40 years. Subjects were divided into groups who had four premolars extractions or non-extraction (Male extraction-16, Male nonextraction-18, Female extraction-19, Female nonextraction-21). All subjects were asked to bite pressure-sensitive sheets into maximum intercuspation with maximum bite force, and OcFr and OcAr were evaluated by measuring the sheet with a CCD camera. Records were taken right after debonding, 1 week, 1 month, 3 months, 6 months and 1 year after debonding. RESULTS: OcFr and OcAr increased gradually in all groups during the 1 year retention period (p 0.05). CONCLUSIONS: Occlusion was improved functionally throughout the 1 year retention, and premolar extraction did not induce a decline in the functional aspect of occlusion.