• Korean Journal of Cleft Lip And Palate
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• v.7 no.2
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• pp.77-91
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• 2004

본 연구의 목적은 반안면왜소증 환자의 하악골 신장술시 초기 치아골격 특성들 중에서 치료결과의 차이에 기여하는 인자를 찾는 것이다. 치료전의 치아골격 특성, 골신장술의 효과와 그 유지상태를 관찰하기 위하여 골신장술 직전(T0), 직후(T1), 추적 2년후(T2)에 측모와 정모 두부방사선 계측사진을 촬영하여 전후방, 수직치아, 비대칭 항목들을 계측하였다. T2 시기의 계측 결과에 따라서 환자들을 1군(양호군, 10명)과 2군(불량군, 9명)으로 분류하였다. 두 군에서 각 시기와 T0-T1, T1-T2 동안의 변화량의 차이를 Mann-Whitney U test, Wilcoxon signed independent t-test, rank test, ANOVA test를 사용하여 분석하였다. pruzansky type이 골신 장술의 성공과 실패 여부와 관계가 깊게 나타났다. T0 시기에 2군은 1군에 비하여 하악골이 후방위치되었고, 하악지 고경(ramus height)이 짧았고, 하악각(gonial angle)이 컸으며, 이환측 하악지가 내측경사되었고, 이환측으로의 이부변위(chin point deviation)가 크게 나타났다. 1군에서 골신장술의 주요한 효과는 하악지 고경의 증가, 하악골의 전방위치, 하악각의 증가, articular angle의 감소에 따른 하약골의 반시계방향 회전, 이환측의 하악지 경사의 증가, 교합면경사와 이부변위의 개선으로 나타났다. 그러나 2군에서는 골신장술을 시행했을 때 1군에 비하여 하악골이 시계방향으로 회전되었고 하악지 고경의 증가량이 작게 나타났다. T2 시기에 2군에서는 하악골의 반시계방향 회전이 나타났고, 하악지 성장이 일어나지 않았으나, 1군은 반대의 경향을 보였다. 이러한 인자들이 골신장술 결과의 차이에 기여하는 것으로 생각된다.

• Restorative Dentistry and Endodontics
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• v.33 no.4
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• pp.341-351
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• 2008

This study investigated the effect of intermittent polymerization on the rate of polymerization shrinkage and cuspal deflection in composite resins. The linear polymerization shrinkage of each composite was measured using the custom-made linometer along with the light shutter specially devised to block the light at the previously determined interval. Samples were divided into 4 groups by light curing method; Group 1) continuous light (60s with light on); Group 2) intermittent light (cycles of 3s with 2s light on & 1s with light off for 90s): Group 3) intermittent light (cycles of 2s with 1s light on & 1s with light off for 120s); Group 4) intermittent light (cycles of 3s with 1s light on & 2s with light off for 180s). The amount of linear polymerization shrinkage was measured and its maximum rate (Rmax) and peak time (PT) in the first 15 seconds were calculated. For the measurement of cuspal deflection of teeth, MOD cavities were prepared in 10 extracted maxillary premolars. Reduction in the intercuspal distance was measured by the custom-made cuspal deflection measuring machine. ANOVA analysis was used for the comparison of the light curing groups and t-test was used to determine significant difference between the composite resins. Pyramid showed the greater amount of polymerization shrinkage than Heliomolar (p < 0.05). There was no significant difference in the linear polymerization shrinkage among the groups. The Rmax was group 4 < 3, 2 < 1 in Heliomolar and group 3 < 4 < 2, 1 in Pyramid (p < 0.05). Pyramid demonstrated greater cuspal deflection than Heliomolar. The cuspal deflection in Heliomolar was group 4 < 3 < 2, 1 and group 4, 3 < 2, 1 in Pyramid (p < 0.05). It was concluded that the reduced rate of polymerization shrinkage by intermittent polymerization can help to decrease the cuspal deflection.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.4
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• pp.423-436
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• 2011

Trauma from occlusion (TFO) is a pathologic alterations which develop in the periodontium as a result of undue masticatory force. The purpose of this article is to review the controversies about TFO. There are evidences that TFO is a risk factor in the progression of periodontitis. Tooth mobility should be reduced by selective occlusal adjustment. TFO can be developed dependent on the masticatory pattern, occlusion and anterior overbite in sound periodontal conditions. Secondary TFO may aggravate unstable occlusion. If "loss of posterior support" was occur, the problems were worsen. Extrusion, migration, rotation and pathologic deviation can be resulted. Opposite contention is the "shortened dental arch" concept. However, these two concepts persue the occlusal stability together. To treat TFO adequately, exact diagnosis and multi-disciplinary treatment should be needed.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.504-508
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• 2008

Delayed eruption and abnormal morphology of the primary incisors following intubation may be due to follicular displacement and localized trauma caused by the process of intubation. Result of such damage included palatal groove formation, defective incisors and acquired clefts. This clinical report presents effect of intubation on the primary dentition of premature low-birth-weight children prior to tooth eruption.

• The korean journal of orthodontics
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• v.31 no.3 s.86
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• pp.311-323
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• 2001

One of the various mechanics used to treat unilateral Class II malocclusion is head gear with asymmetric face bow. We made the finite element models of unilateral Class II maxillary dental arch and power arm asymmetric face bow. We designed this experiment to observe stress distribution of periodontal ligament, reaction force, and displacement and to understand force system, so to predict the therapeutic effect. On the basis of computerized tomograph of maxillary dental arch of 25 years old male with normal occlusion without extraction and orthodontic treatment history, we made finite element models of maxillary dental arch and periodontal ligament. Then we modified that model to unilateral maxillary Class II malocclusion model of which maxillary left molar displaced mesially. Also, We made finite element model of asymmetric face bow of which right outer bow shorter than left by 25mm(RMO, Penta-FormTM/Medium size, 0.045 inch iner bow, 0.072 inch outer bow). After that, retraction force of 250g, 300b, 350g were applied to maxillary first molar. We concluded as follow. 1. The Net force that both maxillary first molars were received increased as the retraction force increased. Mesially positioned tooth received more force than normally positioned tooth. But, both tooth were received distal force, so distal movement occured. 2. Both tooth received buccal lateral force. In analysis of force element, as the retraction force were increased, force of X-axis at mesially positioned tooth decreased, and force of X-axis at normally positioned tooth increased. so lateral force component moved to the side received less force from more force. 3. There were rotation, tipping with distal movement in maxillary first molar. As retraction force were increased, rotation and tipping also increased. More tipping and rotation occured at the side received more force, that is, mesially positioned tooth. Though it Is small change, displacement of same pattern occur in normally positioned tooth

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.232-239
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• 1999

Exfoliation of the primary teeth and eruption of the permanent teeth is a normal and predictable physiologic process. The accurate prediction of tooth development is of major importance in treatment planning for children. Norms that correspond to the child's age and development have been determined by many investigators. However, there are a variety of factors that may hasten, retard, or otherwise affect the normal developmental process. Among the factors that influence tooth eruption is the premature loss of primary teeth. An abscess of a primary molar, followed by bone resorption and early extraction or exfoliation may lead to premature eruprion of the permanent succesor, and a variety of clinical sequelae. I, hereby present the patients who have prematurely erupted permanent successor in Seoul National University Hospital Pediatric Dentistry, and report the clinical and radiologic characteristics, its sequelae, proper managements, and followed up findings.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.2
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• pp.174-182
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• 2024

In patients with multiple missing molars, wear patterns or displacement of anterior teeth, collapsed occlusal plane, and reduction in vertical dimension may occur. Particularly, in case of a few remaining teeth on one side, a removable partial denture has biomechanical disadvantage. For this reason, an implant-assisted removable partial denture with a few implant surveyed crowns can be an alternative. In this case, due to the right mandibular posterior teeth loss, the anterior teeth were severely worn and the occlusal plane was collapsed. With minimal increasing vertical dimension, oral rehabilitation was performed using a maxillary fixed prosthesis and mandibular implant-assisted removable partial denture. As a result, functional and aesthetic clinical outcomes were obtained.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.618-625
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• 2003

The purpose of this study was to analyze the traumatized primary teeth and investigate the occurrence, types, area, cause, place of trauma to primary teeth and seasonal variation in a hospital population, and to evaluate the interval between injury and treatment. A total 411 children with 745 traumatized teeth participated in this study from 1998 to 2000. The results were as follows : 1. There were slightly more boys than girls giving a male-to-girl ratio of 1.74:1.0. The 1-2, 2-3 year old boys and girls had the highest number of traumatic injuries to their primary dentition. 2. The most common injury was concussion. 3. The majority of traumatized teeth are the upper primary central incisors. 4. Falling down was the most common cause of injury in both sexes. The most of the injuries occurred inside home. 5. 46% of the children visited the dental office within 24 hours after traumatic injury. 6. The most common month was October(12.7%), and June(12.2%), May(11.7%) were followed.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.3
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• pp.207-217
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• 2014

The purpose of the present study was to evaluate the relationship between the malocclusion and dental caries in adolescents with permanent dentition. The subjects of the study were 385 adolescents aged 12 to 15 years. Dental Aesthetic Index (DAI) and DMFT index were recorded as clinical indicators of malocclusion and dental caries. The mean Dental Aesthetic Index (DAI) score of the subjects was 12.42 and the mean DMFT index of the subjects was 2.89. Four students (1.04%) were included in the group of orthodontic treatment mandatory, which signifies the handicapping malocclusion. Moreover, the result of gender-specific analysis of the DAI components observed that the prevalence of midline diastema and mandibular overjet were significantly higher among boys (p < 0.05). In 7 components (missing teeth, incisal segment crowding, maxillary anterior irregularity, mandibular anterior irregularity, mandibular overjet, anterior openbite, antero-posterior molar relationship) among the 10 DAI components, abnormal groups showed significantly higher DMFT index than normal groups (p < 0.05). The subjects in the group of definite to handicapping malocclusion (DAI ${\geq}$ 26) showed significantly higher DMFT index than the subjects in the group of minor or no malocclusion (p < 0.01). In addition, the DAI score had significant positive linear correlation with the DMFT index (r = 0.584, p < 0.01). Consequently, the current findings suggested a positive relationship between the malocclusion and caries prevalence. And several specific types of malocclusion were supposed to be significantly correlated with dental caries.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.355-361
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• 2004

Impaction is generally defined as the lack of eruption of a tooth after the normal age for the eruption. An impacted tooth may appear blocked by another tooth, bone, or soft tissue, but cause of tooth impaction is often unknown. The clinician should consider the various treatment options available : (a) No treatment and observation, (b) surgical exposure and orthodontic traction (c) auto transplantation (d) extraction. These cases were about the patients with delayed eruption of maxillary central incisor. We surgically exposed impacted tooth and guided it into normal position by the orthodontic traction. Especially, in case 1, #21 was ectopic impacted state with root dilaceration. It is required to examine further root development and alignment of dentition serially.