• The korean journal of orthodontics
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• v.41 no.3
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• pp.211-218
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• 2011

Objective: This case report describes orthodontic treatment of contracted mandibular arch using a trombone appliance. Methods: A 14-year-old girl with Class II division 2 malocclusion, retroclined maxillary incisors, and buccally displaced maxillary canines required dental expansion in 3 spatial directions to correct the contracted maxillary and mandibular arches. In the initial phase of treatment, the maxillary arch was expanded and distalized using a quad-helix appliance and cervical headgear. Following the expansion and leveling of the maxillary arch, a trombone appliance was used to expand the mandibular arch. On correction of the mandibular arch and provision of sufficient space to level the mandibular teeth, fixed orthodontic treatment phase was initiated. Results: A trombone appliance proved effective in correcting the contracted mandibular arch. Because of labiolingual and transversal expansion, the mandibular dental arch perimeter was increased by 7.4 mm; the misalignment of the mandibular teeth was corrected successfully. Conclusions: A trombone appliance may serve as an appropriate clinical alternative for treating moderate mandibular arch crowding caused by the contraction of the dental arch.

• Journal of the Korea Convergence Society
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• v.12 no.10
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• pp.89-96
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• 2021

This study is aimed to establish the direction of orthodontic treatment by analyzing the differences in the dental arch development due to the cause of short stature. Dental diagnostic tests were conducted on patients who were diagnosed with short stature. Idiopathic short statured children were classified through the paired sampling based on the age and gender of a short statured children with growth hormone shortage. Control groups were classified using same method as above, after selecting candidates with an arch length of less than 3mm and malocclusion. In conclusion, short statured children with growth hormone shortage or idiopathic had the higher rate of crowding and the small value of overbite compared to normal children. Therefore orthodontic treatment for short statured children needs treatment plan included evaluation for Arch length discrepancy to treat a crowding early. This study will provide important data for successful orthodontic treatment according to the characteristics of dental occlusion of short statured children.

• The korean journal of orthodontics
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• v.12 no.2
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• pp.95-108
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• 1982

The purpose of this study was to analyze the growth and development of tooth germ and dental arch related to the bone growth during the fetal period. From 70 maxillae and 61 mandibles of the fetus aged 5, 6, 7, 8, 9 and 10 months, X-ray films were taken and measured. The results were as follows; 1. There was remarkable bone growth in the anterior and posterior area of palatum osseum, that were the intetior portion of both deciduous canines anteriorly and the intero-posterior portion of both deciduous second molars posteriorly, where there was active bone growth and radiate formation of bony trabeculae was found. 2. The Growth of anterior tooth germ was greater than that of posterior tooth germ, so anterior tooth germs were crowded. Especially in maxilla, the tooth germs of deciduous lateral incisors were located inside of dental arch and the tooth germs of deciduous canines were located outside of dental arch. 3. Crowding amount increased with the fetal age because the growth of tooth germs was greater than that of jaw bone. 4. In the growth of upper dental arch, the increase of width was greater than that of length. 5. There was proportional relationship between the area of Palatal Trapezoid and the fetal age.

• The Journal of Advanced Prosthodontics
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• v.12 no.6
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• pp.361-368
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• 2020

PURPOSE. The present study aimed to evaluate the accuracy of a desktop scanner and intraoral scanners based on the volumetric dimensions of a complete arch. MATERIALS AND METHODS. Seven reference models were fabricated based on the volumetric dimensions of complete arch (70%, 80%, 90%, 100%, 110%, 120%, and 130%). The reference models were digitized using an industrial scanner (Solutionix C500; MEDIT) for the fabrication of a computer-aided design (CAD) reference model (CRM). The reference models were digitized using three intraoral scanners (CS3600, Trios3, and i500) and one desktop scanner (E1) to fabricate a CAD test model (CTM). CRM and CTM were then superimposed using inspection software, and 3D analysis was conducted. For statistical analysis, one-way analysis of variance was used to verify the difference in accuracy based on the volumetric dimensions of the complete arch and the accuracy based on the scanners, and the differences among the groups were analyzed using the Tukey HSD test as a post-hoc test (α=.05). RESULTS. The three different scanners showed a significant difference in accuracy based on the volumetric dimensions of the complete arch (P<.05), but the desktop scanner did not show a significant difference in accuracy based on the volumetric dimensions of the complete arch (P=.808). CONCLUSION. The accuracy of the intraoral scanners was dependent on the volumetric dimensions of the complete arch, but the volumetric dimensions of the complete arch had no effect on the accuracy of the desktop scanner. Additionally, depending on the type of intraoral scanners, the accuracy differed according to the volumetric dimensions of the complete arch.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.1
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• pp.169-178
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• 2007

Dental crowding is one of the most common type of malocclusions in the mixed dentition. During the period of transition from the primary to the permanent dentition, minor incisor crowding is often present in the normally developing dentitions, but severe crowding can be caused by arch length/tooth size discrepancy. To determine the need for and appropriate timing of treatment for arch-length discrepancies, clinicians must be knowledgeable about normal development. This paper reviewed the literature on normal dental arch development and proper management of dental crowding according to its severity. Due to variations in the timing and the sequence of permanent tooth eruption, management of dental crowding should be specific to the individual patient.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.3
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• pp.300-304
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• 2010

This study was performed to development a dental three-dimensional laser scanning system and measure the accuracy of new adjustable upper dental impression tray. The metal stock, individual, and new adjustable stock trays were used for 30 stone casts(10 casts each) duplicated a resin master model of maxilla. The dental stone was poured in a vinyl polysiloxane impressions and allowed to set for on hour. The master model and the duplicated casts were digitized using an dental scanning system. The distance between the reference points were measured and analyzed on the graphic image of 3D graphic software of CATIA. The statistical significance of the differences between the groups was determined by a two-way ANOVA. There were no significant differences between the accuracies of the adjustable stock tray and the master model except only anterior arch width on the upper arch. The adjustable upper stock tray showed clinically acceptable accuracies of the study cast produced by them.

• Imaging Science in Dentistry
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• v.48 no.4
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• pp.255-259
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• 2018

Purpose: This study proposes a new ball-type phantom for evaluation of the image layer of panoramic radiography. Materials and Methods: The arch shape of an acrylic resin phantom was derived from average data on the lower dental arch in Korean adult males. Metal balls with a 2-mm diameter were placed along the center line of the phantom at a 4-mm mesiodistal interval. Additional metal balls were placed along the 22 arch-shaped lines that ran parallel to the center line at 2-mm buccolingual intervals. The height of each ball in the horizontal plane was spaced by 2.5 mm, and consequently, the balls appeared oblique when viewed from the side. The resulting phantom was named the Panorama phantom. The distortion rate of the balls in the acquired image was measured by automatically calculating the difference between the vertical and horizontal length using $MATLAB^{(R)}$. Image layer boundaries were obtained by applying various distortion rate thresholds. Results: Most areas containing metal balls (91.5%) were included in the image layer with a 50% distortion rate threshold. When a 5% distortion rate threshold was applied, the image layer was formed with a small buccolingual width along the arch-shaped center line. However, it was medially located in the temporomandibular joint region. Conclusion: The Panorama phantom could be used to evaluate the image layer of panoramic radiography, including all mesiodistal areas with large buccolingual width.

• The korean journal of orthodontics
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• v.30 no.1 s.78
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• pp.19-31
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• 2000

Developmental changes of dental arch width and length from 6.6 to 13.6 yews of age have been studied in twenty boys and thirteen girls in Korean school children. A series of 8 dental casts obtained from each child was measured in the intercanine width, intermolar width and arch length. Afterwards, mean value and each standard deviation of each age group and each gender were obtained, and corresponding graphs were drawn. The finding of this study can be summarized as follows : 1. Maxillary intercanine widths increased until age of 13.5 in males and age of 12.5 in females. On the other hand, mandibular intercanine widths increased until age of 11.5 in males and age of 9.6 in females and after there were no changes. 2. Maxillary intermolar widths increased until age of 13.5, but annual increments reduce from age of 12.5 in both sex. Mandibular intermolar widths increased until age of 13.5 in males and age of 12.5 in females. Annual increments of maxillary intermolar width greater than those of mandibular intercanine width in both sex. 3. Maxillary dental arch lengths increased until age of 10.6 in both sex, and after decreased until age of 13.6. Mandibular dental arch lengths increased until age of 10.5 in males and age of 9.6 in females, and after decreased until a9e of 13.6. 4. Developmental changes of dental arch width and length showed individual variation.

• Anatomy and Cell Biology
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• v.57 no.2
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• pp.288-293
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• 2024

The temporal fascia is a double lamina sandwiching a thick fat layer above the zygomatic bony arch. To characterize each lamina, their developmental processes were examined in fetuses. We observed histological sections from 22 half-heads of 10 mid-term fetuses at 14-18 weeks (crown-rump length, 95-150 mm) and 12 near-term fetuses at 26-40 weeks (crown-rump length, 215-334 mm). The superficial lamina of the temporal fascia was not evident at mid-term. Instead, a loose subcutaneous tissue was attached to the thin, deep lamina of the temporal fascia covering the temporalis muscle. At near-term, the deep lamina became thick, while the superficial lamina appeared and exhibited several variations: i) a mono-layered thick membrane (5 specimens); ii) a multi-layered membranous structure (6) and; iii) a cluster of independent thick fasciae each of which were separated by fatty tissues (1). In the second and third patterns, fatty tissue between the two laminae was likely to contain longitudinal fibrous bands in parallel with the deep lamina. Varying proportions of the multi-layered superficial lamina were not attached to the zygomatic arch, but extended below the bony arch. Whether or not lobulation or septation of fatty tissues was evident was not dependent on age. The deep lamina seemed to develop from the temporalis muscle depending on the muscle contraction. In contrast, the superficial lamina developed from subcutaneous collagenous bundles continuous to the cheek. Therein, a difference in development was clearly seen between two categories of the fasciae.

• The korean journal of orthodontics
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• v.28 no.1 s.66
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• pp.17-27
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• 1998

Study on growth change of dental arch is considered to both an important data in orthodontic diagonsis and treatment planning as well as analysis of treatment results , also, arch form is important in anthropology and dentistry, even more so in prosthodontics and orthodontics. In the field of orthodontics, studies on the functional aspect of upper and lower teeth and maintenance of stability of dentition and occlusion were carried out from the early days. Some of the early studies include explanation of growth change in dental arch from measuring directly fom human stroll, and afterwards, cephalometrics x-rays were introduced; accordingly, studies using cephalometric measurement and linear measurements of study models were often performed. By this method, arch width, arch depth and perimeters were measured, and growth change or dental arch was studied. The subject ror this study were sn children(boys and girls or ages from 3 yens to 12 years from Kang-won district and Seoul, who has no history of orthodontic treatment and who show healthy status and normal growth and development. Cephalometric x-ray, panoramic x-ray, and study model were taken for each subject consecutively for 2 years, and the subjects are still followed up. 400 pairs of study models from the past two years were used in this study; mesio-distal diameater of each tooth, intercanine width, intermolar width, canine depth, molar depth and arch perimeters were measured. Afterwards, mean value and each standard deviation of each age group and each gender were obtained, and representation graph were drawn. The following conclusion were obtained. 1. Intercanine width showed gradual increase until the age of 10-years and after that, showed no increase. 2. Intermolar width in upper arch showed gradual increase : intermolar width in lower arch showed no significant chang, and after the age of 9-years, showed increase. 3. Cainine arch depth showed relatively rapid increase after the age of 6-years, and this pattern was more obvious in lower arch. 4. Molar arch depth increased gradually in both archs and it decrease after the age of 10-years : this phenomenon was more prominent in the lower arch. 5. Arch perimeter showed gradual inerease and convert to plateau at the age of 10-years, after that, it decreased. this pattern was more prominent in lower arch.