• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.5
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• pp.390-398
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• 2005

Purpose: The aim of this study was to evaluate the skeletal and dentoalveolar dimensional changes following surgically-assisted rapid maxillary expansion (SARME). Patients & methods: Thirteen adults who had been treated by SARME for transverse maxillary deficiency from May 2000 to December 2003 were evaluated. The SARME procedure was the subtotal Le Fort I osteotomy combined with pterygomaxillary separation and anterior midpalatal osteotomy. Dental study casts and posteroanterior cephalometric radiographs were taken before operation, after removal of expansion device, and follow up period. Nasal cavity width, skeletal and dentoalveolar parameters were measured pre- and post-operatively. Results: 1. Mean nasal cavity width was increased 12%$(0{\sim}21%)$ of total expansion after retention. 2. Mean maxillary interdental width was increased 70%$(47{\sim}99%)$, 95%$(84{\sim}115%)$, and 77%$(57{\sim}94%)$ of total expansion in the canine, the first premolar, and the first molar region, respectively after retention. 3. Mean maxillary alveolar bone width was increased 66%$(42{\sim}84%)$, 74%$(42{\sim}94%)$, and 57%$(31{\sim}78%)$ of total expansion in the canine, the first premolar, and the first molar region, respectively after retention. 4. Mean palatal vault depth was decreased 1.3 mm ($0.5{\sim}2.0$ mm) after retention. 5. Mean interdental and alveolar bone width of the mandibular canine and intermolar width of mandible were slight increased as maxilla was expanded after retention. 6. There were statistical differences between preoperative and postoperative values of nasal cavity, all maxillary interdental and interalveolar widths, palatal vault depth, mandibular interdental and interalveolar width of canine(paired t-test, p<0.05). 7. The maxillary interdental and alveolar bone width were decreased approximately 25% of total expansion by relapse at follow up period. Conclusion: In conclusion, most amounts of maxillary interdental expansions were acquired with the expansion of the maxilla by SARME. For preventing the relapse, approximately 25% of the overexpansion was needed.

• Imaging Science in Dentistry
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• v.42 no.2
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• pp.83-88
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• 2012

Purpose : The aim of this study was to investigate the initial effects of maxillary expansion therapy with Hyrax appliance and to evaluate the related changes in maxillary sinus volume. Materials and Methods : Thirty patients (20 females, 10 males; 13.8 years) requiring maxillary expansion therapy, as part of their comprehensive orthodontic treatment, were examined. Each patient had cone-beam computed tomography (CBCT) images taken before (T1) and after (T2) maxillary expansion therapy with a banded Hyrax appliance. Multiplanar slices were used to measure linear dimensions and palatal vault angle. Volumetric analysis was used to measure maxillary sinus volumes. Student t tests were used to compare the pre- and post-treatment measurements. Additionally, differences between two age groups were compared with Mann-Whitney U test. The level of significance was set at p=0.05. Results : Comparison of pre-treatment to post-treatment variables revealed significant changes in the transverse dimension related to both maxillary skeletal and dental structures and palatal vault angle, resulting in a widened palatal vault (p<0.05). Hard palate showed no significant movement in the vertical and anteroposterior planes. Nasal cavity width increased on a mean value of 0.93mm(SD=0.23, p<0.05). Maxillary sinus volume remained virtually stable. No significant age differences were observed in the sample. Conclusion : Hyrax expansion therapy did not have a significant impact on maxillary sinus volume.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.270-277
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• 2005

The purpose of this study was to clarify the palatal volume and anterior palatal slope of the children with class II div.1 malocclusion and normal occlusion in mixed dentition(Hellman dental age III A) using three-dimensional laser scanner. Samples were consisted of 31 children with skeletal class II div.1 malocclusion in mixed dentition and 29 children with normal occlusion and profile among the contestants in 2000-2004 Healthy Dentition Contest in Seoul. Totally 60 maxillary study model were taken. Each cast was scanned by three-dimensional laser scanner (Breuckmann opto-TOP HE, INUS, Korea) and shaped into the three-dimension image by Rapidform 2004 program(INUS, Korea). And the palatal volume and anterior palatal slope of each cast were calculated by Rapidform 2004 program(INUS, Korea). The values were statistically compared and evaluated by independent samples t-test with 95% of significance level. The results were as follows: 1. Palatal volume was significantly lesser in children with class II div.1 malocclusion than that of normal occlusion in mixed dentition(p<0.05). 2. No significant difference in the anterior palatal slope and palatal height was found between the children with class II div.1 malocclusion and normal occlusion in mixed dentition(p>0.05). 3. Palatal length was significantly greater in children with class II div.1 malocclusion than that of normal occlusion in mixed dentition(p<0.01). 4. Intercanine and intermolar width were significantly lesser in children with class II div.1 malocclusion than those of normal occlusion in mixed dentition(respectively p<0.05 and p<0.01).

• The korean journal of orthodontics
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• v.53 no.2
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• pp.106-115
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• 2023

Objective: To evaluate the null hypothesis that there is no difference in a set of clinical predictors of potentially impacted canines between low-risk patients with and without displaced canines. Methods: The normal canine position group consisted of 30 patients with 60 normally erupting canines ranked in sector I (age, 9.30 ± 0.94 years). The displaced canine group comprised 30 patients with 41 potentially impacted canines ranked in sectors II to IV (age, 9.46 ± 0.78 years). Maxillary lateral incisor crown angulation, inclination, rotation, width, height, and shape, as well as palatal depth, arch length, width, and perimeter composed a set of clinical predictors, which were evaluated on digital dental casts. Statistical analyses consisted of group comparisons and variable correlations (p < 0.05). Results: There was a significant association between sex and mesially displaced canines. Unilateral canine displacement was more prevalent than bilateral displacement. The crown of the maxillary lateral incisors was significantly angulated more mesially and rotated mesiolabially in low-risk patients with displaced canines, who also had a shallower palate and shorter anterior dental arch length. Lateral incisor crown angulation and rotation, as well as palatal depth and arch length, were significantly correlated with the canine displacement severity. Conclusions: The null hypothesis was rejected. Maxillary lateral incisor angulation inconsistent with the "ugly duckling" stage as well as a shallow palate and short arch length are clinical predictors that can significantly contribute to the early screening of ectopic canines in low-risk patients.

• The korean journal of orthodontics
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• v.50 no.5
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• pp.304-313
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• 2020

Objective: The aim of this study was to evaluate the stability of bimaxillary surgery involving bilateral intraoral vertical ramus osteotomy performed with or without presurgical miniscrew-assisted rapid palatal expansion (MARPE) in adult patients with skeletal Class III malocclusion. Methods: A total of 40 adult patients with skeletal Class III malocclusion were retrospectively divided into two groups (n = 20 each) according to the use of MARPE for the correction of transverse maxillomandibular discrepancy during presurgical orthodontic treatment. Serial lateral cephalograms and dental casts were analyzed until 6 months after surgery. Results: Before presurgical orthodontic treatment, there was no significant differences in terms of sex and age between groups. However, the difference of approximately 3.1 mm in the maxillomandibular intermolar width was statistically significant (p < 0.001). Two days after surgery, the mandible had moved backward and upward without any significant intergroup difference. Six months after surgery, the maxillary intercanine (2.7 ± 2.1 mm), interpremolar (3.6 ± 2.4 mm), and intermolar (2.0 ± 1.3 mm) arch widths were significantly increased (p < 0.001) relative to the values before presurgical orthodontic treatment in the MARPE group; these widths were maintained or decreased in the control group. However, there was no significant difference in surgical changes and the postsurgical stability between the two groups. No significant correlations existed between the amount of maxillary expansion and postsurgical mandibular movement. Conclusions: MARPE is useful for stable and nonsurgical expansion of the maxilla in adult patients with skeletal Class III malocclusion who are scheduled for bimaxillary surgery.

• The korean journal of orthodontics
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• v.45 no.5
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• pp.236-244
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• 2015

Objective: The aim of this study was to investigate three-dimensional molar displacement after distalization via miniscrews and a horizontal modification of the trans-palatal-arch (TPA). Methods: The subjects in this clinical trial were 26 Class II patients. After the preparation of a complete set of diagnostic records, miniscrews were inserted between the maxillary 2nd premolar and 1st molar on the palatal side. Elastic modules connected to the TPA exerting an average force of 150-200 g/side parallel to the occlusal plane were applied. Cone-beam computed tomography was utilized to evaluate the position of the miniscrews relative to the adjacent teeth and maxillary sinus, and the direction of force relative to molar furcation. The distances from the central point of the incisive papilla to the mesiopalatal cusps of the 1st maxillary molars and the distances between the mesiopalatal cusps of the left and right molars were measured to evaluate displacement of the maxillary molars on the horizontal plane. Interocclusal space was used to evaluate vertical changes. Results: Mean maxillary 1st molar distalization was $2.3{\pm}1.1mm$, at a rate of $0.4{\pm}0.2mm/month$, and rotation was not significant. Intermolar width increased by $2.9{\pm}1.8mm$. Molars were intruded relative to the neighboring teeth, from 0.1 to 0.8 mm. Conclusions: Distalization of molars was possible without extrusion, using the appliance investigated. The intrusive component of force reduced the rate of distal movement.

• The korean journal of orthodontics
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• v.49 no.6
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• pp.360-371
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• 2019

Objective: We sought to determine the predictors of midpalatal suture expansion by miniscrew-assisted rapid palatal expansion (MARPE) in young adults. Methods: The following variables were selected as possible predictors: chronological age, palate length and depth, midpalatal suture maturation (MPSM) stage, midpalatal suture density (MPSD) ratio, the sella-nasion (SN)-mandibular plane (MP) angle as an indicator of the vertical skeletal pattern, and the point A-nasion-point B (ANB) angle for anteroposterior skeletal classification. For 31 patients (mean age, 22.52 years) who underwent MARPE treatment, palate length and depth, MPSM stage and MPSD ratio from the initial cone-beam computed tomography images, and the SN-MP angle and ANB angle from lateral cephalograms were assessed. The midpalatal suture opening ratio was calculated from the midpalatal suture opening width measured in periapical radiographs and the MARPE screw expansion. Statistical analyses of correlations were performed for the entire patient group of 31 subjects and subgroups categorized by sex, vertical skeletal pattern, and anteroposterior skeletal classification. Results: In the entire patient group, the midpalatal suture opening ratio showed statistically significant negative correlations with age, palate length, and MPSM stage (r = -0.506, -0.494, and -0.746, respectively, all p < 0.01). In subgroup analyses, a strong negative correlation was observed with the palate depth in the skeletal Class II subgroup (r = -0.900, p < 0.05). Conclusions: The findings of this study indicated that age, palate length, and MPSM stage can be predictors of midpalatal suture expansion by MARPE in young adults.

• Restorative Dentistry and Endodontics
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• v.47 no.1
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• pp.6.1-6.9
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• 2022

Objectives: This study investigated the internal morphology of mesiobuccal (MB) roots of maxillary molars with a second mesiobuccal (MB2) canal. Materials and Methods: Forty-seven maxillary first or second molars from Brazilians were scanned using micro-computed tomography. The following measurements were obtained from the MB roots: root thickness, root width, and dentin thickness of the buccal aspect of the first mesiobuccal (MB1) canal, between the MB1 and MB2 canals, and the palatal aspect of the MB2 and MB1 canals at 3 mm from the root apex and in the furcation region. For statistical analysis, the Student's t-test and analysis of variance with the post-hoc Tukey test were used (α = 0.05). Results: In maxillary molars with an MB2 canal, MB roots were significantly thicker (p = 0.0014) and narrower (p = 0.0016) than in maxillary molars without an MB2 canal. The dentin thickness of the palatal aspect of the MB1 canal was also significantly greater than that of MB roots without an MB2 canal at 3 mm from the root apex (p = 0.0007) and in the furcation region (p < 0.0001). In the furcation region of maxillary molars with an MB2 canal, the dentin thickness between the MB1 and MB2 canals was significantly smaller than that in the buccal and palatal aspects (p < 0.0001). Conclusions: The internal morphology of MB roots of maxillary molars with an MB2 canal revealed differences in dentin thickness, root diameter, and distance between the canals when compared with maxillary molars without an MB2 canal.

• The korean journal of orthodontics
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• v.49 no.2
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• pp.89-96
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• 2019

Objective: The purpose of this study was to assess the long-term stability of rapid palatal expansion (RPE) followed by full fixed edgewise appliances. Methods: This study included 67 patients treated using Haas-type RPE and non-extraction edgewise appliance therapy at a single orthodontic practice. Serial dental casts were obtained at three different time points: pretreatment ($T_1$), after expansion and fixed appliance therapy ($T_2$), and at long-term recall ($T_3$). The mean duration of the $T_1-T_2$ and $T_2-T_3$ periods was $4.8{\pm}3.5years$ and $11.0{\pm}5.4years$, respectively. The dental casts were digitized, and the computed measurements were compared with untreated reference data. Results: The majority of treatment-related increases in the maxillary and mandibular arch measurements were statistically significant (p < 0.05) and greater than expected for the untreated controls. Although many measurements decreased postretention ($T_2-T_3$), the net gains persisted for all of the measurements evaluated. Conclusions: The use of RPE therapy followed by full fixed edgewise appliances is an effective method for increasing maxillary and mandibular arch width dimensions in growing patients.

• The korean journal of orthodontics
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• v.39 no.3
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• pp.146-158
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• 2009

Objective: The purpose of this study was to reveal the position of the incisive foramen in relation to the incisive papilla and cusp tips. Methods: Plaster models and CT images of 25 adult orthodontic patients were used to measure the width of the incisive canal and positions of the anterior and posterior borders of the incisive foramen in relation to the incisive papilla. Results: The palatal surface distance from the interdental papilla between the maxillary central incisors to the posterior border of the incisive foramen along the palatal surface was 1.7 fold of the distance from the interdental papilla between the central incisors to the posterior border of the incisive papilla. The distance between the posterior border of the incisive papilla and posterior border of the incisive foramen along the palatal surface was 6.15 ${\pm}$ 1.75 mm. The anteroposterior position of the posterior border of the incisive foramen was slightly anterior to the lingual cusp tips of the maxillary 1st premolars. The width of the incisive foramen was 4.03 ${\pm}$ 0.64 mm, therefore it is recommended to position the mini-implant more than 3 mm laterally when placing a mini-implant lateral to the incisive foramen, from the center. Conclusions: These results can be used as a reference in presuming the position of the incisive foramen when placing mini-implant in the anterior palate area.