• 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.

• The korean journal of orthodontics
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• v.26 no.5 s.58
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• pp.535-546
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• 1996

The purpose of this study was to classify mandibular dental arch forms based on Raberin's method, and to compare Raberin's arch forms with that of the Korean's, and to designate arch form of bracket level according to distance between cusp tip and buccal surface of bracket level. The sample consisted of 159 mandibular dental casts showing normal occlusion which was taken from 62 males and 97 females of the Korean, aging from 13 to 25 years. The model was taken by X-ray. The landmarks were cusp points which expressed the mandibular dental arch line of cusp tips and buccal points which were measured from cusp tips to buccal surfaces of bracket level. The landmarks on the film were digitized, and measurements and statistics were performed. The results were as follows; 1. The models were classified as type 1, type 2, type 3, type 4 and type 5 by the author, and polynomial functions of the six degree and R-square values were calculated using statistical method, and each calculated equations explained each group with the least R-square value of 0.97, and each arch forms' were plotted. 2. The distribution of type 1 was $17.6\%$, type 2 $20.8\%$, type 3 $20.8\%$, type 4 $16.3\%$ and type 5 $24.5\%$. 3. The Korean arch form was characterized by larger width, smaller height compared to the French arch form. 4. The designated arch form of bracket level, viz the distance between cusp point and buccal point was calculated. The distance between cusp point and buccal point of incisor was 1mm, canine 1.9mm, first premolar 2.5mm, second premolar 2.6mm, first molar 2.7mm and second molar 2.7mm.

• The korean journal of orthodontics
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• v.22 no.3 s.38
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• pp.675-690
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• 1992

The purpose of this study was to obtain the lingual morphology (size, angulation, contour, eminence) of adults with normal occlusion in order to provide the basic data for lingual bracket and lingual arch form in Korean. The subjects (Male: 50, Female: 50) were selected who have normal occlusion and dental casts were prepared. Tooth size, angulation, arch width, horizontal contour, lingual eminence were measured for all 28 teeth both upper and lower arch. The results were as follows: 1. Measuring items of all individual teeth for adults with normal occlusion were obtained. 2. In comparison tests, there was a statistically difference between intermolar widths $(\underline{6}\;to\;\underline{6})$ before occlusal reduction and intermolar width $(\underline{6}\;to\;\underline{6},\underline{7}\;to\;\underline{7})$ after occlusal reduction only all the other measuring items showed no statistically differences. 3. There was small variation in horizontal contour of lingual surface on lower incisors and upper and lower bicuspids. The other teeth showed somewhat greater variations. 4. There was offset between canine and bicuspid in upper arch while there was no prominent offset in lower arch.

• The korean journal of orthodontics
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• v.11 no.2
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• pp.143-150
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• 1981

Casts of 180 Korean male and female with normal occulsion of early permanent dentition (from dental age of Hellman III C, to IV A) were studied to measure the mesiodistal crown diameters and to calculate the coefficients of correlation between the teeth. From the study, the following conclusions were made: 1. Mesiodistal dimension of maxillary central incisors, canines, first molars and mandibular canines, first premolars, second premolars and first molars of male are larger than that of female. 2. Korean teeth are roughly intermediate between those of American Caucasian and those of American Negro. 3. In both sexes, the relation between the first and second premolars appeared highly correlated not only in the maxillary arch but also in the mandibular arch, and the relation between the central incisor and lateral incisor appeared highly correlated in the mandibular arch. 4. The relation between the maxillary and mandibular first premolars appeared highly correlated in both sex, and the relation between the maxillary canine and mandibular canine in male as well as between the maxillary central incisor and mandibular central incisor in female appeared highly correlated.

• The korean journal of orthodontics
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• v.15 no.1
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• pp.115-121
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• 1985

This study was intended to investigate the effect of mesiodistal crown widths of the anterior teeth on the incisor relationship and to determine whether incisor width ratio and anterior width ratio could be used to assess interarch tooth width harmony. From the casts taken from 63 subjects, 26 of open bite, 18 of deep bite and 19 of normal over bite with age of 17-20, mesiodistal crown widths of maxillary and mandibular 6 anterior teeth were measured with Boley gauge. On the basis of tooth measurements, anterior and incisor width ratio were calculated. The cephalograms were taken from same subjects to measure the degree of over bite and over jet and to compare the craniofacial bony structures between open bite, deep bite and normal over bite. Correlations among the anterior width ratio, incisor width ratio, over bite and over jet were calculated. The results were as follows. 1. There were no differences in mesiodistal widths of anterior teeth, incisor width ratio and anterior width ratio between open bite, deep bite and normal over bite. 2. The incisor width ratio and anterior width ratio can be useful in the assessment of tooth width harmony because the incisor width ratio and anterior width ratio were stable statistically and significantly correlated with each other. 3. Over bite and over jet were not correlated with incisor width ratio and anterior width ratio.

• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.199-206
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• 2008

Purpose: Variation in the morphology of gingival papilla may be determined by the shape and position of anatomic crown as well as contact area and embrasure form of individual teeth. However, periodontal biotype classification is regarded to be subjective because of the lack of definite criteria. In this study, we defined the objective parameters which constitute the periodontal biotype and measured their relationship. Materials and Methods: 109 of dental casts were prepared using three dimensional scanner and specialized reconstruction software, then acquiredvirtual models were sent to the 20 professional dentists to define the specific periodontal biotypes. Several parameters around periodontal structures were measured from the virtual models; facial surface area of the anterior tooth (AT), anterior papillary area (AP), proportion of the dento-papillary complex, clinical papillary length (PL), and clinical papillary angle (PA). Statistical analysis was performed to confirm the relationship among parameters. Results: Coincidence rate of periodontal biotype within observers was $63.77{\pm}16.05%$. Coincidence rate between observers was $76.15{\pm}16.43%$. Among the parameters measured, PL showed the most positive correlations and PA presented the most negative correlations. The parameter of the AP and PL of six maxillary anterior teeth showed significant correlation coefficient. Conclusion: Anterior papillary area and clinical papillary length would be objective parameters for determining the consistent periodontal biotypes.

• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.79-88
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• 1988

The purpose of this study was to investigate the factors which might be related to mandibular third molar eruption and to predict the possibility of whether or not it will be erupted. The material of this study was lateral cephalometric radiograms, pantomograms and dental casts obtained from 70 patients (19 males, 51 females) ranging in age from 18.0 to 32.1 years. They were devided into erupted group and impacted group of mandibular third molars. For the comparison of each group, a total of 20 measurement items were employed and the data were analyzed by means of computer statistical method. As a result of this study, the following conclusion can be made; 1. The longer mandibular body length and narrower mandibular ramus width, the higher eruption tendency of the lower third molar, but the degree of genial angle was not related to mandibular third molar eruption. 2. The lower percentage of posterior mandibular body height to anterior mandibular body height, the higher eruption tendency of the lower third molar. 3. The total tooth size, including the lower second molar, appeared to be larger in the impacted group than in the erupted group of the lower third molar. 4. The arch length discrepancy of the impacted group was more severe in contrast with the erupted group of the lower third molar.

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.1
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• pp.39-47
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• 2021

Compared to conventional method, if metal framework of removable partial denture is fabricated by selective laser melting, various laboratory works are omitted, saving time and simplifying the process. In addition, metal framework with homogeneous density can be obtained, expecting excellent mechanical properties, especially resistance to fatigue fracture. In these cases, impression were taken using conventional methods in partial edentulous patients, master casts were fabricated and scanned to obtain digital data. After designing the metal frameworks on the scanned data, removable partial dentures were fabricated using selective laser melting methods. Through these procedure, satisfactory outcomes were achieved both in functional and esthetic aspects.

• The Journal of Advanced Prosthodontics
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• v.14 no.4
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• pp.236-249
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• 2022

PURPOSE. The present study compared the accuracy between digital and conventional implant impressions. MATERIALS AND METHODS. The experimental models were divided into six groups depending on the implant location and the scanning span. Digital impressions were captured using the intraoral optical scanner TRIOS (3Shape, Copenhagen, Denmark). Conventional impressions were taken with the monophase impression material based on addition-cured silicones, Honigum-Mono (DMG, Hamburg, Germany). A high-precision laboratory scanner D900 (3Shape, Copenhagen, Denmark) was used to obtain digital data of resin models and stone casts. Surface tessellation language (STL) datasets from scanner were imported into the analysis software Geomagic Qualify 14 (3D Systems, Rock Hill, SC, USA), and scan body deviations were determined through two-dimensional and three-dimensional analyses. Each scan body was measured five times. The Sidak t test was used to analyze the experimental data. RESULTS. Implant position and scanning distance affected the impression accuracy. For a unilateral arch implant and the mandible models with two implants, no significant difference was observed in the accuracy between the digital and conventional implant impressions on scan bodies; however, the corresponding differences for trans-arch implants and mandible with six implants were extremely significant (P<.001). CONCLUSION. For short-span scanning, the accuracy of digital and conventional implant impressions did not differ significantly. For long-span scanning, the precision of digital impressions was significantly inferior to that of the traditional impressions.

• The korean journal of orthodontics
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• v.36 no.1 s.114
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• pp.84-90
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• 2006

The aims of this study were to investigate the prevalence of spaced, closed, and crowded primary dentitions by sex and arch in Korean children from Kanghwa, and to determine the frequency of the primate and developmental spaces. The differences in the mesiodistal crown diameters and the arch dimensions between the spaced, closed, and crowded primary dentitions were also evaluated. Dental casts of 102 preschool children (57 males and 45 females, aged $4{\sim}5$ years) were studied. The prevalence of spacing in the primary dentition was 63.2% In males and 57.8% in females. The frequency of spacing was greater in males than in females, and greater in the maxillary arch than in the mandibular arch. The crowns were significantly larger and the arches significantly narrower in closed and crowded dentitions than in those with spacing (p<0.05). The results showed that the prevalence of spacing was lower than that found in previous studies and the presence of spacing in the anterior region was related to the mesiodistal crown diameter and the intercanine width.