Korean Journal of Orthodontics最新文献

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.

Objective: The aim of this study was to evaluate changes in the nasal soft tissues, including movements of landmarks, changes in linear distances, and volumetric changes, using three-dimensional (3D) stereophotogrammetry after microimplant-assisted rapid palatal expansion (MARPE) in adult patients.

Methods: Facial data were scanned using a white light scanner before and after MARPE in 30 patients. In total, 7 mm of expansion was achieved over a 4-week expansion period. We determined 10 soft tissue landmarks using reverse engineering software and measured 3D vector changes at those points. In addition, we calculated the distances between points to determine changes in the width of the nasal soft tissues. The volumetric change in the nose was also measured.

Results: All landmarks except pronasale and subnasale showed statistically significant movement on the x-axis. Pronasale, subnasale, alar right, and alar left showed significant movement on the y-axis, while all landmarks except subnasale showed significant movement on the z-axis. The alar base width, alar width, and alar curvature width increased by 1.214, 0.932, and 0.987 mm, respectively. The average volumetric change was 993.33 mm³, and the amount of increase relative to the average initial volume was 2.96%.

Conclusions: The majority of soft tissue landmarks around the nasal region show significant positional changes after MARPE in adults. The nose tends to widen and move forward and downward. The post-treatment nasal volume may also exhibit a significant increase relative to the initial volume. Clinicians should thoroughly explain the anticipated changes to patients before MARPE initiation.

Moving the mandibular posterior teeth into a severely atrophic edentulous space is a challenge. A carefully designed force-and-moment system that results in bodily protraction of the posterior teeth with balanced bone resorption and apposition is needed in such cases. This report describes the treatment of a 19-year-old woman with missing mandibular first molars due to juvenile periodontitis. Miniscrews were used as absolute anchorage during protraction of the mandibular second and third molars. Bodily mesial movement of the mandibular second and third molars was achieved over a distance of 11 to 17 mm after 39 months of orthodontic treatment.

Objective: The aims of the present study were to evaluate the changes in the maximum lip-closing force (MLF) after orthodontic treatment with or without premolar extractions and verify the correlation of these changes with dentoskeletal changes.

Methods: In total, 17 women who underwent nonextraction orthodontic treatment and 15 women who underwent orthodontic treatment with extraction of all four first premolars were included in this retrospective study. For all patients, lateral cephalograms and dental models were measured before (T0) and after (T1) treatment. In addition, MLF was measured at both time points using the Lip De Cum LDC-110R® device. Statistical analyses were performed to evaluate changes in clinical variables and MLF and their correlations.

Results: Both groups showed similar skeletal patterns, although the extraction group showed greater proclination of the maxillary and mandibular incisors and lip protrusion compared to the nonextraction group at T0. MLF at T0 was comparable between the two groups. The reduction in the arch width and depth and incisor retroclination from T0 to T1 were more pronounced in the extraction group than in the nonextraction group. MLF in the extraction group significantly increased during the treatment period, and this increase was significantly greater than that in the nonextraction group. The increase in MLF was found to be correlated with the increase in the interincisal angle and decrease in the intermolar width, arch depth, and incisor-mandibular plane angle.

Conclusions: This study suggests that MLF increases to a greater extent during extraction orthodontic treatment than during nonextraction orthodontic treatment.

Hemifacial microsomia (HFM) patients may experience emotional withdrawal during their growth period due to their abnormal facial appearance. Distraction osteogenesis at an early age to improve their appearance can encourage these patients. Some abnormalities of the affected side can be overcome by distraction osteogenesis at an early age. However, differences in the growth rate between the affected and unaffected sides during the rest of the growth period are inevitable due to the characteristics of HFM. Therefore, re-evaluation should be performed after completion of growth in order to achieve stable occlusion through either orthognathic surgery or camouflage orthodontic treatment. An eight-year-old patient visited the clinic exhibiting features of HFM with slight mandibular involvement. He received phase I treatment with distraction osteogenesis and a functional appliance. Distraction osteogenesis was performed at the right ramus, which resulted in an open bite at the right posterior dentition. After distraction osteogenesis, a functional appliance and partial fixed appliance were used to achieve extrusion of the affected posterior dentition and settlement of the occlusion adjustment on the unaffected posterior dentition. The patient visited the clinic regularly for follow-up assessments, and at the age of 20 years, he showed facial asymmetry of the mandible, which had deviated to the right side. He received orthodontic treatment to improve the occlusion of his posterior dentition after the growth period. Without orthognathic surgery, stable occlusion and a satisfactory facial appearance were obtained through camouflage orthodontic treatment.

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.

Odontogenic keratocysts (OKCs) are one of the most aggressive cysts in the oral and maxillofacial area because of their high recurrence rate and infiltrative behavior. In growing patients with OKCs, a radical treatment approach might cause numerous complications, including the disturbance of jaw growth and loss of the involved tooth. This case report describes successful comprehensive orthodontic treatment combined with marsupialization of the cyst in a young girl who exhibited an OKC with impacted teeth. The 10-year-old girl presented with an OKC extending from the mandibular symphysis through the left mandibular body, with ectopic impaction of the mandibular left canine and first premolar, as well as congenitally missing bilateral mandibular second premolars. Interestingly, spontaneous improvement of the positions of the ectopic impacted teeth, along with a reduction in the size of the cyst, occurred during marsupialization. The sequential use of removable and fixed appliances enabled orthodontic traction of the impacted teeth. The treatment outcome was stable at 2.5 years after the end of the treatment. We speculate that comprehensive orthodontic treatment combined with marsupialization can be an effective treatment strategy for patients with OKCs, especially when they are encountered in young, growing patients with impacted teeth.

Objective: The aim of this study was to compare the accuracy and reliability of measurements performed using two different software programs on digital models generated using two types of plaster model scanners (a laser scanner and a computed tomography [CT] scanner).

Methods: Thirty plaster models were scanned with a 3Shape laser scanner and with a Flash CT scanner. Two examiners performed measurements on plaster models by using digital calipers and on digital models by using Ortho Analyzer (3Shape) and Digimodel® (OrthoProof) software programs. Forty-two measurements, including tooth diameter, crown height, overjet, overbite, intercanine and intermolar distances, and sagittal relationship, were obtained.

Results: Statistically significant differences were not found between the plaster and digital model measurements (ANOVA); however, some discrepancies were clinically relevant. Plaster and digital model measurements made using the two scanning methods showed high intraclass coefficient correlation values and acceptable 95% limits of agreement in the Bland-Altman analysis. The software used did not influence the accuracy of measurements.

Conclusions: Digital models generated from plaster casts by using laser and CT scanning and measured using two different software programs are accurate, and the measurements are reliable. Therefore, both fabrication methods and software could be used interchangeably.