• The Journal of Korean Academy of Prosthodontics
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• v.36 no.2
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• pp.323-335
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• 1998

Clinically, the curve of Spee is widely applied as a determined level of the occlusal curvature when the oral rehabilitation and the reconstruction of the prosthesis is needed at the malalignment dentition due to the missing, extrusion, and the inclination of the teeth. The purpose of this study was to analyze the curve of Spee of the occlusal curvature which influences to the occlusal form and the location three dimensionally, and then was to measure the radius and the degree of curvature of the curve of Spee and also was to investigate the influence to the cuspal inclination according to the change of the inclination of the curve of Spee which was analyzed by AutoCAD R.13 program at the gnathological cast and the cephalometric radiograph. The following results were obtained : 1. The radius of the curve of Spee was the mean of $11.74{\pm}3.64cm$ in the model, $12.75{\pm}4.63cm$ in the radiograph and there was no significant difference statistically between the model and the radiograph(P>0.001). 2. The radius and the degree of curvature of the curve of Spee showed negative correlation(r=-0.80), while the radius and the degree of curvature of the curve of Spee in relation to the length of the curve of Spee did not show correlation. 3. The case of the curve of Spee inclined to the posterior, that is. $Post.M{\theta}$ group showed the mean of $4.73{\pm}3.64$, positive correlation to the P2m, M1mm, M1dm, M2dm, and especially the greatest correlation coefficient to the mesial inclination angle of the mesio-buccal cusp tip of the first molar(r=0.70). 4. The case of the curve of Spee inclined to the anterior, that is, $Ant.M{\theta}$ group showed the mean of $3.28{\pm}3.59$, positive correlation to the P2m, M1mm, and also the greatest correlation coefficient to the mesial inclination angle of the mesio-buccal cusp tip of the first molar(r=0.78

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.413-420
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• 2011

Garre's osteomyelitis is associated with bacterial infection and bone necrosis resulting from obstruction of blood supply. The most common cause for Garre's osteomyelitis is odontogenic infection that originates from periodontal tissue or dental pulp. Subperiosteal abscess may also cause Garre's osteomyelitis in the progress of the infection. Mandible is more often affected than maxilla, most commonly in the permanent first molar region of mandible. Clinically, it results in a hard swelling over the jaw, producing facial asymmetry. Meanwhile, radiograph shows a characteristic feature of irregular pulpal cavity, showing new periosteal proliferation located in successive layers to the condensed cortical bone on stimulated site. The treatment method for Garre's osteomyelitis are removal of the infection source, root canal treatment, antibiotic medication, and incision and drainage. This report presents a case of Garre's osteomyelitis under 15 years old. The patient was successfully treated by antibiotic medication accompanied with root canal treatment. Since the symptom of pediatric patients is less severe than adult, careful diagnosis with history taking and clinical examination is necessary. Furthermore long-term follow-up examination is needed to prevent recurrence even after the symptom disapears.

• The korean journal of orthodontics
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• v.31 no.1 s.84
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• pp.1-13
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• 2001

The extraction lot orthodontic treatment can be adopted for aligning crowded dentition, improving facial esthetics and solving a skeletal discrepancy as alternative for a surgical option. Mandibular second premolar extraction was often selected as treatment plan when there we very little or no space shortage in lower arch or limited retraction of the lower incisors was required. The primary object of this study was evaluate a pretreatment condition and examine the amount of tooth movement ior a mandibular second premolar extraction in growing patients. Pretreatment and posttreatment lateral cephalograms of 14 cases that had their four first premolar extracted (4/4 group), 15 cases with upper first and lower second premolar extraction (4/5 group) were selected. Structural method superimposition was conducted to evaluate a difference of dental change between 4/4 and 4/5 group. The results were as follows, 1. Pretreatment factor for 4/4 extraction or 4/5 extraction choice included maxillary incisor axis to occlusal plane, Class II molar relationship, IMPA and interincisal angle. 2. The amount of molar anterior movement in 4/5 group was greater than that of 4/4 group(p<0.05). 3. There was no significant difference between 4/4 group and 4/5 group in aspects of maxillary tooth movement(p<0.05).

• Journal of Periodontal and Implant Science
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• v.36 no.1
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• pp.147-154
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• 2006

Surgical intervention in the posterior maxillary region requires detailed knowledge of maxillary sinus anatomy and the possible anatomical variations. This study evaluated the incidence, location of maxillary sinus septa by using radiographic (panoramic radiography and computed tomography) findings and comparison of panoramic radography with CT in antral anatomical variation. This study was based on data from 70 sinuses in partial dentate maxilla. The sample consisted of 61 patients(25 women and 36 men, with ages ranging between 19 and 77 years and a mean age of $49.4{\pm}11.3$ years) who were being treatment-planned to receive implant-supported restorations. First, the panoramic images were examined for the presence of antral septa by radiologist and examiner who don't know about CT findings. And incidence of antral septa was evaluated using an axial plane of CT image. The incidence of septa was compared between panoramic radiography and CT. The accuracy of the incidence was compared between radiologists and dentists. A total of 20 septa were found in 70 sinuses on CT image and the prevalence of one or more septa per sinus was found to be 28.6%. The assumed incidence of septa on panoramic radiography was $27.6%{\pm}2.2%$ in radiologist and $31.9%{\pm}5.8%$ in dentists. Erroneous diagnosis rate was 11.42% in radiologist and 15.96% in dentists. 40% of antral septa were located in the anterior(premolar) region, 30% of septa were located in the middle(first molar) and posterior(second molar) region separately. Prior to implant placement, it seems appropriate to consider panoramic radiography as a standard radiographic examination and periapical radiographs may be used to complete the findings in regions not sharply depicted in the panoramic radiograph. And cross-sectional imaging should be used in sites with severe bone loss and close proximity of the maxillary sinus.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.701-704
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• 2004

In this case, we would like to discuss about the single rooted deciduous mandibular first molar. The deciduous mandibular molar of a five years old boy was shown to have a single root, bilaterally. Ordinarily, the maxilary molars have three roots and the mandibular molars have two roots. However, when the hertwig's epithelial root sheath do not invaginate properly during tooth development, root fusion can occur from the absence of root separation. Molars with fused roots not only have unfavorable crown to root ratio, but also according to many reports, have higher probability of having multiple congenitally missing teeth or dens invaginatus in the maxillary incisors, consequently requiring preventive dental treatment In addition, disorders such as ectodermal dysplasia, syndactyly, clinodactyly, bluish sclera can also be related to this condition. Root fusion is known to be of autosomal recessive inheritance. Up to date, single rooted molars have been reported several times in permanent dentitions but hardly in deciduous dentition, which is the motive for this paper.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.3
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• pp.253-263
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• 2022

A buccal pit is a prominent point-like depression that appears at the cervical end of the mandibular molar developmental grooves. A defective buccal pit can be defined as a buccal pit in which the continuity of the dentinoenamel junction is broken and the pit extends to the dentinal level. This study aimed to determine the frequency of buccal pits and defective buccal pits in un-erupted mandibular first and second molars using cone-beam computed tomography (CBCT). The analysis was performed on CBCT images taken from 417 Korean children and adolescents who visited the Department of Pediatric Dentistry, Yonsei University Dental Hospital between 2004 and 2020. Based on cross-sectional views of CBCT images, buccal pits were categorized into 4 classes according to the depth of the pits. The expression rate of the buccal pits was 29.1%. The prevalence of defective buccal pits was 7.9%. The buccal pits tended to develop bilaterally. To date, this is the most comprehensive study on the frequency of buccal pits with the largest sample size. This was the first attempt worldwide to analyze the depth of the buccal pit using CBCT images and to define a defective buccal pit worldwide.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.1
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• pp.95-103
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• 2022

The first permanent molars play a key role in maxillofacial development and occlusion. The purpose of this study is to investigate the characteristics and development stages of first molars with delayed eruption, and to evaluate their associations with congenital missing teeth. Eight-year-old patients who had delayed eruption in their first molars were classified into 75 patients with physical barriers and 77 patients without physical barriers. The development stages of the first and second molars in the delayed area were analyzed using Nolla method from the panoramic radiographs. The relationship between congenital missing teeth and delayed area was also investigated. Delayed eruption of first molars were more common in the maxilla alone. With the presence of physical barriers, male patients showed higher frequency in unilateral cases, while female patients had higher bilateral cases when there was no physical barrier. Delayed development of first molars were observed in delayed eruption area. In the absence of physical barriers, adjacent second molars were also developed slowly and the incidence of congenital missing teeth was high in delayed area. If first molars with delayed eruption are observed, clinical and radiographical follow-ups are necessary for the evaluation of their developmental stages and congenital missing teeth.

• The korean journal of orthodontics
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• v.42 no.3
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• pp.138-143
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• 2012

Objective: To evaluate the short-term effect of fangchinoline, an anti-inflammatory drug widely used in Asia, on root resorption that is associated with orthodontic tooth movement. Methods: Twenty-four Wistar rats were randomly divided into 6 groups. Mesial forces of 0, 50, or 100 g were applied to the maxillary first molar of the rats in each group for 14 days by activating nickel-titanium closed-coil springs. One-half of the rats receiving each of these treatments also received injections of 200 ${\mu}L$ fangchinoline every 2 days. Finally, movement of the maxillary first molars was measured using digitized radiographs. The molars were extracted and the surfaces of the root resorption craters were recorded using a scanning electron microscope. The distance the molars moved and resorption-area ratio was measured, and results were analyzed using 2-way ANOVA tests. Results: There were no statistical differences in the distances the first molars moved under 50 or 100 g force, regardless of treatment with fangchinoline. However, the resorption area ratios were significantly smaller in those rats that were treated with both tension and fangchinoline than in those rats treated by tension alone. Conclusions: Fangchinoline reduced the resorption area ratio in rats and is therefore an important means of alleviating root resorption.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.4
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• pp.266-274
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• 2020

Objectives: Melatonin induces human stem cells, converts pre-osteoblasts to mature osteoblasts, and reduces the duration of this transition. However, melatonin itself prevents activation of osteoclasts. Here, we evaluate the role of melatonin in prevention of bisphosphonate-related osteonecrosis of the jaw. Materials and Methods: In this experimental-interventional study, 30 rats were evaluated in 3 groups. The first and second groups received saline and zoledronic acid, respectively, for 4 weeks and the third group received 4 weeks of zoledronic acid and 3 weeks of melatonin simultaneously. First-right-maxillary-molar extraction was performed for all animals, which were sacrificed after 4 weeks of recovery. The extraction sockets were examined histologically for the presence of osteonecrosis, number of osteoclasts and fibroblasts, severity of inflammation, and vascularization. Data were analyzed by chi-square, one-way ANOVA, Tukey, Kruskal-Wallis and Fisher's exact statistical tests (α=0.05). Results: Osteonecrosis was observed in 20%, 90%, and 70% of the first, second and third groups, respectively (P=0.008). The lowest number of osteoclasts and fibroblasts was seen in the third group. Conclusion: Melatonin may effectively prevent some undesirable side effects of bisphosphonates. However, further studies are required to confirm the results of this study.

• The korean journal of orthodontics
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• v.49 no.5
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• pp.279-285
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• 2019

Objective: This study evaluated the efficiency of anchorage provided by temporary anchorage devices (TADs) in maxillary bicuspid extraction cases during retraction of the anterior teeth using a fixed appliance. Methods: Patients aged 12 to 50 years with malocclusion for which bilateral first or second maxillary bicuspid extractions were indicated were included in the study and randomly allocated to the TAD or control groups. Retraction of the anterior teeth was achieved using skeletal anchorage in the TAD group and conventional dental anchorage in the control group. A computed tomography (CT) scan was performed after alignment of teeth, and a second CT scan was performed at the end of extraction space closure in both groups. A three-dimensional superimposition was performed to visualize and quantify the maxillary first molar movement during the retraction phase, which was the primary outcome, and the stability of TAD movement, which served as the secondary outcome. Results: Thirty-four patients (17 in each group) underwent the final analysis. The two groups showed a significant difference in the movement of the first maxillary molars, with less significant anchorage loss in the TAD group than that in the control group. In addition, TAD movement showed only a slight mesial movement on the labial side. On the palatal side, the mesial TAD movement was greater. Conclusions: In comparison with conventional dental anchorage, TADs can be considered an efficient source of anchorage during retraction of maxillary anterior teeth. TADs remain stable when correctly placed in the bone during the anterior tooth retraction phase.