Ki-Taeg Jang

The position of maxillary canine impactions and the influenced factors to adjacent root resorption in the Korean population

The purpose of this study was to evaluate the position and aspects of maxillary canine impactions in the Korean population and investigate its comparison with the previous reports, while aiding in the establishment of diagnosis and treatment planning by revealing the influential factors of root resorption associated with such impactions. The subjects of this study consisted of 186 teeth from 148 patients, who had visited Seoul National University Dental Hospital due to impacted canines and had taken computerized tomographic images and panorama radiographic images. As a result, maxillary canine impaction in the Korean population occurred 1.5 times more often in females (F:M = 89:59) than males. Regarding the position of impaction, there were three times more buccal impactions (B:P = 140:46) than palatal impactions. The occurrence of root resorption was as high as 49.5 per cent. In evaluating the influential factors affecting adjacent root resorption, the significance of the impacted angulation was insufficient (P = 0.652). However, the buccopalatal position (P < 0.0001) and mesiodistal placement (P = 0.006, 0.037) of the impacted tooth were determined to be significant factors. Therefore, the adjacent root resorption caused by impacted maxillary canines can be stated to exhibit a greater amount of resorption as the positional proximity of the canine crown and lateral incisor root increases.

Interrelationship between the position of impacted maxillary canines and the morphology of the maxilla

INTRODUCTION The aim of this study was to examine whether there is a relationship between the position of impacted maxillary canines and the morphology of the maxilla. METHODS The palatally impacted canine group included 18 boys and 27 girls with an average age of 12 years 9 months (±2 years 1 month). The buccally impacted canine group comprised 19 boys and 26 girls with an average age of 12 years 2 months (±1 year 4 months). Arch length/intermolar width × 100 was used as the value for comparison of maxillary arch shapes, and palatal vault depth/intermolar width × 100 was used to compare the shapes of palate between the 2 groups. Each category was directly measured from the diagnostic model. RESULTS Both the arch length/intermolar width × 100 and the palatal vault depth/intermolar width × 100 formulas showed statistically significant differences (P <0.0001), indicating differences in the shape of maxillary arch and the palatal vault between the 2 groups. CONCLUSIONS The shape of the maxillary arch was narrower and longer in the palatally impacted canine group compared with the buccally impacted canine group, and the palatally impacted canine group had a deeper palatal vault than did the buccally impacted canine group.

Morphological relationship analysis of impacted maxillary canines and the adjacent teeth on 3-dimensional reconstructed CT images

OBJECTIVE To examine whether there is a relationship between maxillary canine impaction and the morphologic characteristics of the maxillary dentition, especially the root of the lateral incisor. MATERIALS AND METHODS In this study, we selected only patients with unilateral maxillary canine impaction to compare the morphologic characteristics of the dentition on the impaction side and the clinically normal eruption side. The sample size was decided to be 40 based on the pilot study. To minimize bias depending on sex and location of the maxillary canine impaction, we selected equal numbers (20) of boys and girls, and equal cases (20) of buccal impaction and palatal impaction. Under the aforementioned conditions, the mean age was 13.5 ± 2.3 years. The multislice spiral computed tomography images of these 40 subjects were converted into three-dimensional (3D) reconstructed images using the OnDemand 3D program (Cybermed Co, Seoul, Korea). Then we measured the morphologic characteristics of the individual teeth on the obtained 3D teeth images. RESULTS Length and volume of the maxillary lateral incisors roots were significantly smaller on the impaction side compared with the normal eruption side (P = 0.001 and P = 0.006, respectively). The width and volume of the canines crown were significantly greater on the impaction side compared with the normal eruption side (P = 0.020 and P < .0001, respectively). CONCLUSION These results might help to prove the hypothesis that the smaller-sized lateral incisor roots and greater-sized canine crowns are the influential etiologic factors in maxillary canine impaction.

IMPACTION OF PRIMARY TEETH ASSOCIATED WITH ODONTOMA: CASE REPORTS

Odontomas generally appear as small, solitary, or multiple radio-opaque lesions found on routine radiographic examinations. It is a comparatively common odontogenic tumor, and may lead to interfere with the eruption of its associated tooth. In general, odontomas occur more often in permanent dentition and are very rarely associated with primary teeth. This report deals with five rare cases of primary teeth impaction associated with odontomas, with spontaneous eruption occurring in all five cases after simple surgical removal of the odontoma. Impacted primary teeth may be associated with defects in development and eruption of their permanent successors, and thus long-term observation is necessary until the permanent successors erupt.

A STUDY OF NEW-PATIENT DISTRIBUTION AND THE MOTIVES FOR VISITING IN THE DEPARTMENT OF PEDIATRIC DENTISTRY AT SEOUL NATIONAL UNIVERSITY DENTAL HOSPITAL

The number of patients requesting services of pediatric dental clinics has been steadily increasing in South Korea. The pediatric dental clinics are comprised of hospital-based clinics and local clinics. The purpose of this study was to analyze new-patient distribution and to survey the motives for visiting the department of pediatric dentistry at Seoul National University Dental Hospital(SNUDH), utilizing questionnaires for parents from May to July 2010. The results are as follows: 1. Age distribution showed that 0-3 year-olds formed the largest group of 29.3%. The average age of patients was 6.2 years old. 2. In the surveys for the parents, the major reason for visiting SNUDH was the referral from other clinics(30.6%). 3. The 75% of patients previously visited other clinics before visiting SNUDH. 1) The greater number of patients(52%) visited general practitioners clinic than pediatric specialists(48%). 2) More than 90% of the patients visited SNUDH after visiting other clinics for reassuring diagnosis and referrals. 3) The crucial deterring factor of being treated at SNUDH was difficult accessibility.

REMINERALIZATION EFFECT OF INTERPROXIMAL CARIES ADJACENT TO GLASS IONOMER RESTORATIONS: IN VITRO STUDY USING QLF

This in vitro study compared the remineralization of incipient interproximal caries in the presence of three glass ionomer cements(highly-filled glass ionomer cement, resin-modified glass ionomer cement, compomer) and a resin composite(control). Thirty-two extracted premolars were selected based upon the lack of any visible demineralization. The teeth were coated in a transparent acid resistant nail varnish leaving mm square. The teeth were subjected to the demineralizing buffer for 3 days and quantitative light-induced fluorescence(QLF) images of the subjects were taken. Proximal restoration was simulated by placing tooth specimens and the various glass ionomer cements in closed containers with artificial saliva at and pH 7.0 with constant circulation. Further QLF images were subsequently taken at 30, 60, and 90 days. The changes of mineral loss() were evaluated by QLF and the change of () were compared between groups in order to evaluate the effects of remineralization. All data were analyzed using ANOVA and the post-HOC Dunnett C multiple comparison test at p(changes of mineral loss) increased for all treatments, the increases for three glass ionomer groups were significantly higher than that for the resin group at first month period. As time went on, the amount of decreased.

Prediction of agenesis of the mandibular second premolar using the developmental stages of the mandibular canine, first premolar, and second molar

OBJECTIVE The aim in this study was to suggest a standard for early diagnosis of agenesis of the mandibular second premolars (L5) by estimating the developmental stages of the mandibular canines (L3), first premolars (L4), and second molars (L7). DESIGN Among all 5136 pediatric patients aged 5-11 years who received panoramic radiographs between June 2008 and December 2009 at Seoul National University Dental Hospital, 215 control patients and 74 agenesis patients who met inclusion criteria were analyzed. The developmental stages of all L3, L4, L5, and L7 of control and agenesis patients were estimated using the method proposed by Demirjian. To identify the tooth (L3, L4, L7) with the developmental pattern most similar to that of L5, Kendall rank correlation coefficients and Bootstrap method were used. To verify that patients with agenesis of L5 show delayed development, Wilcoxon rank sum test was used. To identify the stages in which to diagnose agenesis of L5, we performed survival analysis. RESULTS There was a significant correlation between the developmental stages of L3, L4, L7 and L5. The developmental stages of those three teeth in the agenesis group were delayed compared with those in the control group at certain ages. If the developmental stages of at least two of those three teeth reach Demirjian stage D without the calcification of L5, agenesis of L5 can be confirmed. CONCLUSIONS Agenesis of L5 can be confirmed when two of the three teeth (L3, L4, L7) reach Demirjian stage D.

A Pilot Study of Relationship Between Early Childhood Caries Experience and Chair–side Test Results for Caries-Risk Assessment

본 연구는 임상에서 사용되는 진단도구들이 소아에서 우식위험도와 상관관계를 가지는지 여부를 확인하고, 소아에서 우식위험도를 효과적으로 반영하는 지표가 무엇인지 알아보기 위함이다. 32명의 6세 미만의 소아를 두 군(I군 : dmft 6)으로 나누었다. Plaque-check PH을 이용해 치태의 pH를 측정하고, Saliva-check buf...

The Simple Regression Model of Gonial Angles : Comparison between Panoramic Radiographs and Lateral Cephalograms

The aim of this study was to enhancing the panoramic radiograph’s clinical use for assessing mandibular measurements and formulating a function of those measurements from panoramic radiographs and lateral cephalograms in children. The panoramic radiographs and lateral cephalograms of 99 former orthodontic patients with skeletal class III malocclusion were selected. In each radiograph, gonial angles, ramus heights, and distance between lower incisors and symphysis were measured. The values of the studied parameters were compared by paired t-test, Pearson’s correlation test and regression analysis. The mean value of the gonial angle in panoramic radiographs was 125.49°, and the value in lateral cephalograms was 127.50°. The Pearson’s correlation coefficient (ρ) between mean values of gonial angle in each radiograph was 0.945 (p < 0.001). The relationship between the gonial angle measurements obtained from each radiographs was represented as ‘Gonial angle (Lateral cephalograms) = 0.920 X Average gonial angle (Panoramic radiographs) + 12.072’ in the linear function. The coefficients of ramus heights, and distance between lower incisors and symphysis portrayed weaker correlations than gonial angles. A panoramic radiograph could be used to determine the gonial angle as accurately as a lateral cephalogram, and each gonial angle showed a strong positive relation. A panoramic radiograph is a useful tool for examining vertical growth pattern of patients, as well as a lateral cephalogram.

MESIODENS EXTRACTION OF A PATIENT WITH ROBINOW SYNDROME UNDER GENERAL ANESTHESIA

Robinow syndrome is skeletal dysplasia with both autosomal dominant and recessive inheritance patterns. It is characterized by short-limbed dwarfism, abnormalities in the head and face, as well as vertebral segmentation. A 2-year-7-month old boy with Robinow syndrome had visited Seoul National University Dental Hospital, for the evaluation of tooth palatal eruption on maxilla. He had micrognathia, delayed tooth eruption, cleft lip with bifid uvula. He also had an erupted mesiodens on the palatal side of maxillary primary incisors, which was tuberculated and 8mm in major diameter. The patient was scheduled for mesiodens extraction under general anesthesia. He was a young child with delayed development, so general anesthesia was inevitable. General anesthesia was induced and maintained with inhalation agent, Sevoflurane. There were no postoperative complications related to anesthesia and dental treatment. Robinow syndrome patients have craniofacial dysmorphism and eruption disorders. Therefore, he requires regular check-ups as well as dental managements. [J Korean Dis Oral Health Vol.12, No.1: 1-5, June 2016]