• The Journal of Korean Academy of Prosthodontics
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• v.57 no.4
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• pp.475-482
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• 2019

This report is a case of 76-year old male patient who had difficulty in swallowing, pronunciation and suffered regurgitation of food. The patient lacks uvula and both tonsils, had short palatoglossal arch and soft palate, as well as defective left palatopharyngeal arch. The height and width of the soft palate defect were measured by reconstructing the Computed Tomography (CT) image in three dimensions. Phonation and soft palate obstructing ability were examined by nasometry and nasal endoscopy. Evaluations on phonetics and swallowing were done and improvements were shown. The patient was satisfied with the results of treatment.

• The Journal of Advanced Prosthodontics
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• v.12 no.6
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• pp.338-343
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• 2020

PURPOSE. The present study aimed to investigate the relationships between the crown form of the upper central incisor and their labial inclination, overbite, and overjet. MATERIALS AND METHODS. Maxillary and mandibular casts of 169 healthy dentitions were subjected to 3D dental scanning, and analyzed using CAD software. The crown forms were divided into tapered, square, and ovoid based on the mesiodistal dimensions at 20% of the crown height to that at 40%. The degree of labial inclination of the upper central incisor was defined as the angle between the occlusal plane and the line connecting the incisal edge and tooth cervix. The incisal edges of the right upper and lower central incisor that in contact with lines parallel to the occlusal plane were used to determine the overbite and overjet. One-way ANOVA was performed to compare the labial inclination, overbite, and overjet among the crown forms. RESULTS. The crown forms were classified into three types; crown forms with a 20%/40% dimension ratio of 1.00±0.01 were defined as square, >1.01 as tapered, and <0.99 as ovoid. The labial inclination degree was the greatest in tapered and the least in square. Both overbite and overjet in tapered and ovoid were higher than those in square. CONCLUSION. Upper central incisor crown forms were related to their labial inclination, overbite, and overjet. It was suggested that the labial inclination, overbite, and overjet should be taken into consideration for the prosthetic treatment or restoring the front teeth crowns.

• The Journal of Advanced Prosthodontics
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• v.14 no.5
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• pp.294-304
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• 2022

PURPOSE. The purpose of this study was to evaluate the influence of different palatal vault configurations on the accuracy and scan speed of intraoral scans (IO) of completely edentulous arches. MATERIALS AND METHODS. Three different virtual models of a completely edentulous maxillary arch with different palatal vault heights- Cl I moderate (U-shaped), Cl II deep (steep) and Cl III shallow (flat)-were digitally designed using CAD software (Meshmixer; Autodesk, USA) and 3D-printed using SLA-based 3D-printer (XFAB; DWS, Italy) (n = 30; 10 specimens per group). Each model was scanned using intraoral scanner (Trios 3; 3Shape^TM, Denmark). Scanning time was recorded for all samples. Scanning accuracy (trueness and precision) were evaluated using digital subtraction technique using Geomagic Control X v2020 (Geomagic; 3DSystems, USA). One-way analysis of variance (ANOVA) test was used to detect differences in scanning time, trueness and precision among the test groups. Statistical significance was set at α = .05. RESULTS. The scan process could not be completed for Class II group and manufacturer's recommended technique had to be modified. ANOVA revealed no statistically significant difference in trueness and precision values among the test groups (P=.959 and P=.658, respectively). Deep palatal vault (Cl II) showed significantly longer scan time compared to Cl I and III. CONCLUSION. The selection of scan protocol in complex cases such as deep palatal vault is of utmost importance. The modified, adopted longer path scan protocol of deep vault cases resulted in increased scan time when compared to the other two groups.

• The korean journal of orthodontics
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• v.52 no.5
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• pp.334-344
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• 2022

Objective: This study aimed to systematically analyze the effect and stability of miniscrew-assisted rapid palatal expansion (MARPE) to provide a reference for the clinical treatment of patients with maxillary transverse deficiency (MTD). Methods: We searched PubMed, Science Direct, Web of Science, Embase, Cochrane Library, CNKI, and Wanfang Database for relevant studies published before February 18, 2021 and selected them according to the eligibility criteria. The Cochrane Handbook for Systematic Reviews (version 5.1.0) criteria were used for the quality assessment of randomized controlled trials, while the scoring protocol of the methodological index for non-randomized studies was used for non-randomized controlled trials. Statistical analysis was performed using the RevMan5.3 software. Results: All the included studies showed a relatively high success rate of expansion. The changes in both the intermolar and alveolar widths after MARPE were statistically significant. MARPE exhibited greater skeletal expansion effects than did conventional RPE. The midpalatal suture was opened in parallel after MARPE. A small amount of relapse was observed 1 year after expansion. MARPE caused tooth inclination and a decrease in alveolar height, but it was less significant than in conventional RPE. Conclusions: MARPE may be an effective treatment modality for patients with MTD. It causes great transverse skeletal expansion in late adolescence. In comparison to conventional RPE, MARPE has lower detrimental periodontal effects and has certain clinical advantages.

• The korean journal of orthodontics
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• v.53 no.2
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• pp.125-136
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• 2023

Before progress was recently made in the application of temporary anchorage devices (TADs) in bio-mechanical design, orthodontists were rarely able to intrude molars to reduce upper posterior dental height (UPDH). However, TADs are now widely used to intrude molars to flatten the occlusal plane or induce counterclockwise rotation of the mandible. Previous studies involving clinical or animal histological evaluation on changes in periodontal conditions after molar intrusion have been reported, however, studies involving human histology are scarce. This case was a Class I malocclusion with a high mandibular plane angle. Upper molar intrusion with TADs was performed to reduce UPDH, which led to counterclockwise rotation of the mandible. After 5 months of upper molar intrusion, shortened clinical crowns were noticed, which caused difficulties in oral hygiene and hindered orthodontic tooth movement. The mid-treatment cone-beam computed tomography revealed redundant bone physically interfering with buccal attachment and osseous resective surgeries were followed. During the surgeries, bilateral mini screws were removed and bulging alveolar bone and gingiva were harvested for biopsy. Histological examination revealed bacterial colonies at the bottom of the sulcus. Infiltration of chronic inflammatory cells underneath the non-keratinized sulcular epithelium was noted, with abundant capillaries being filled with red blood cells. Proximal alveolar bone facing the bottom of the gingival sulcus exhibited active bone remodeling and woven bone formation with plump osteocytes in the lacunae. On the other hand, buccal alveolar bone exhibited lamination, indicating slow bone turnover in the lateral region.

• Journal of Korean Dental Science
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• v.16 no.2
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• pp.172-181
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• 2023

Purpose: To investigate the effect of epidermal growth factor (EGF) with collagen matrix (CM) for increasing gingival thickness. Materials and Methods: In five mongrel dogs, bilateral gingival defects were surgically made on the maxillary canines. After two months, either a subepithelial connective tissue graft (group SCTG) or CM with EGF (0.1 ug/ml, group EGF) was grafted, and the flap was coronally positioned to cover the graft materials. The animals were sacrificed after three months. Intraoral scanning was performed for soft tissue analysis. Histologic and histomorphometric analyses were performed. Result: Two animals exhibited wound dehiscence during the healing phase, leaving three for analysis. No statistically significant difference was found in soft tissue changes (P>0.05). The level of gingival margin (GM) increased in both groups (1.02±0.74 mm in group SCTG vs. 1.24±0.83 mm in group EGF). Linear increases at the GM pre-augmentation in the soft tissue profile were 1.08±0.58 mm in group SCTG and 0.96±0.73 mm in group EGF. Histomorphometric parameters (keratinized tissue height, tissue thickness, and rete peg density) were not significantly different between the groups (P>0.05). Conclusion: EGF loaded onto CM led to comparable gingival phenotype enhancement to SCTG.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.6
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• pp.368-375
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• 2013

Purpose: This study is to evaluate the location of descending palatine artery, the anatomy of pterygomaxillary junction, and the association between the obtained anatomic values and several variables. Methods: We studied 40 patients who were treated for dentofacial deformites from January 2010 to December 2012 in Ulsan University Hospital, Ulsan, Korea. Cone beam computed tomogram (CBCT) was done for all patients. The reference point was approximately 5 to 7 mm above anterior nasal spine on axial image. We evaluated the location of the greater palatine canal (line a: on the coronal view, the shortest line between the center of greater palatine canal and pterygoid fossa; distance a: the distance of line a). We also measured the thickness (line b: on the coronal view, the shortest line between maxillary posterior sinus wall and pterygoid fossa; distance b: distance of line b), width (line c: on the coronal view, the line perpendicular to the line b and the nearest line from the most concave point of lateral pterygoid plate to the medial pterygoid plate; distance c: distance of line c) and height (line d: on sagittal view, the vertically longest line of pterygoid junction; distance d: the distance of line d) in pterygomaxillary junctions. We evaluated the association between the obtained anatomic values and several variables (sex, age, height and weight). Results: The mean distance a was 4.78 mm, mean distance b was 5.53 mm, mean distance c was 8.01 mm and mean distance d was 13.22 mm. The differences between age and mean distance c and weight and mean distance d in pterygomaxillary junctions are statistically significant. Conclusion: There apparently is anatomic variation of pterygomaxillary junctions by various values, particularly weight and age in a Korean clinical population.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.2
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• pp.107-114
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• 2001

Objectives : To compare jaw bone density of young adults (control group) and post-menopausal women(experimental group) in periapical and panoramic film. Materials and Methods : The bone mineral density values of lumbar and femur were measured by dual-energy X-ray absorptiometry(DEXA) and T scores of lumbar were obtained. T scores were classified into 3 group (T<-2.5, $-2.5{\leqq}T<-1$, $-1{\leqq}T$). Radiographic densities of alveolar bones were measured from interdental bones of premolar, molar areas in the maxilla and mandible and expressed into copper step wedge thickness by Scion $Image^{(R)}$ program. We considered these values of step wedge thickness as bone density of alveolar bone. Panorama mandibular index(PMI) was calculated by the method that the height of the inferior cortex of the mandible was divided by the height from the lower border of the mandible to the superior edge of the mental foramen. Bone density of alveolar bone and PMI were analysed statistically. Results : There were significant differences in bone mineral density of lumbar and femoral neck between control and experimental groups. There were also significant differences in bone density of premolar and molar area of jaw between control and experimental groups by MANOVA test. When considered lumbar T variables, there was only difference in interdental bone density of maxillary molar area between control and experimental group, but there was interaction. Interdental bone density of experimental group was appeared higher in $-1{\leqq}T$ group and lower in T<-2.5 group than control group. There was significant difference in PMI between control and experimental groups, but there was also inter action, thus, PMI of experimental group was appeared higher in $-1{\leqq}T$ group and lower in T<-2.5 group than control group. Conclusion : There were significant differences of alveolar density and cortical bone thickness between young men and post-menopausal women in periapical and panoramic film. These differences were dependent on lumbar T.

• Journal of Periodontal and Implant Science
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• v.47 no.6
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• pp.372-380
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• 2017

Purpose: The aim of this prospective pilot study was to compare alveolar ridge preservation (ARP) procedures with open-healing approach using a single-layer and a double-layer coverage with collagen membranes using radiographic and clinical analyses. Methods: Eleven molars from 9 healthy patients requiring extraction of the maxillary or mandibular posterior teeth were included and allocated into 2 groups. After tooth extraction, deproteinized bovine bone mineral mixed with 10% collagen was grafted into the socket and covered either with a double-layer of resorbable non-cross-linked collagen membranes (DL group, n=6) or with a single-layer (SL group, n=5). Primary closure was not obtained. Cone-beam computed tomography images were taken immediately after the ARP procedure and after a healing period of 4 months before implant placement. Radiographic measurements were made of the width and height changes of the alveolar ridge. Results: All sites healed without any complications, and dental implants were placed at all operated sites with acceptable initial stability. The measurements showed that the reductions in width at the level 1 mm apical from the alveolar crest (including the bone graft) were $-1.7{\pm}0.5mm$ in the SL group and $-1.8{\pm}0.4mm$ in the DL group, and the horizontal changes in the other areas were also similar in the DL and SL groups. The reductions in height were also comparable between groups. Conclusions: Within the limitations of this study, single-layer and double-layer coverage with collagen membranes after ARP failed to show substantial differences in the preservation of horizontal or vertical dimensions or in clinical healing. Thus, both approaches seem to be suitable for open-healing ridge preservation procedures.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.6
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• pp.509-512
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• 2007

Purpose: The Le Fort I osteotomy is a commonly performed maxillary procedure for dentofacial deformity. One of the risks of this procedure is major hemorrhage resulting from injury to the descending palatine artery. So it is very important to know the exact position of the descending platine artery. An increased understanding of the position of this artery can minimize the intra-operative bleeding while allowing extension of the bone cuts to achieve exact positioning maxilla. The aim of this investigation was to study the position of the descending palatine artery as it relates to the Le Fort I osteotomy. Methods and patients: Total 40 patients who underwent Le Fort I osteotomy in SNUDH OMFS were studied in this study. We measured the distance from the pyriform aperture to the descending palatine artery (DPA distance) using a ruler. We investigated the relationship between DPA distance, the distance from A point to the McNamara line on lateral cephalography and the patient's body height. Results: The average distances from the pyriform rim to the descending palatine artery were 35.3 mm on the right (range: $30{\sim}40mm$) and 33.7mm (range: $30{\sim}41mm$) on the left in males. Those in females were 33.4 mm on the right (range: $28{\sim}40mm)$ and 32.8mm (range: $27{\sim}38mm$) on the left. The significances between the distance the DPA distance, the body height and the distance from A point to McNamara line were not found. Conclusion: Injury to the descending palatine artery during Le Fort I osteotomy can be minimized by not extending the osteotomy more than 30 mm posterior to the pyriform aperture in mal, and 27 mm in female.