• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권4호
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• pp.320-328
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• 2006

Purpose: The aim of this study was to evaluate the effects of pterygomaxillary separation on dimensional changes of dental arch following surgically-assisted rapid maxillary expansion (SARME). Patients and Methods: Eighteen adults who had been treated by SARME for transverse maxillary deficiency from May 2000 to August 2005 were evaluated. Thirteen patients (Group 1) were treated with subtotal Le Fort I osteotomy including pterygomaxillary separation and anterior midpalatal osteotomy. The same operation was performed in five patients (Group 2) except pterygomaxillary separation. Dental study casts were taken before operation and after removal of expansion device. And then, skeletal and dental parameters were measured pre- and post-operatively. Results: 1. Changes of mean interdental width 1) In group 1, mean maxillary interdental width was increased 70%($47{\sim}99%$), 95%($84{\sim}115%$), and 77%($57{\sim}94%$) of total expansion on canine, first premolar, and first molar region, respectively after retention. 2) In group 2, mean maxillary interdental width was increased 77%($59{\sim}100%$), 78%($45{\sim}107%$), and 86%($57{\sim}116%$) of total expansion on canine, first premolar, and first molar region, respectively after retention. 3) There was a statistical difference between the change of interdental width of group 1 and group 2 at first premolar(p<0.05). 2. Changes of mean interalveolar width 1) In group 1, mean maxillary alveolar bone width was increased 66%($42{\sim}84%$), 74%($42{\sim}104%$), and 57%($31{\sim}78%$) of total expansion on canine, first premolar, and first molar region, respectively after retention. 2) In Group 2, mean maxillary alveolar bone width was increased 73%($55{\sim}98%$), 67%($36{\sim}89%$), and 59%($48{\sim}73%$) of total expansion on canine, first premolar, and first molar region, respectively after retention. 3) There were no statistical differences between group 1 and group 2 at each teeth area. Conclusion: These results suggest that SARME without pterygomaxillary separation may allow the relatively equal expansion at both anterior and posterior teeth area and most amounts of maxillary interdental expansions were acquired with the expansion of the maxilla by SARME.

• Journal of Korean Dental Science
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• 제4권1호
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• pp.1-5
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• 2011

Purpose: Exact knowledge of the location and dimension of the pulp chamber help to maintain the pulp healthy during operative procedure and also reduces the risk of perforation of pulp chamber during root canal treatment. This in-vivo study was carried out to measure critical morphology of pulp chamber of mandibular molar using intra-oral periapical radiograph. Materials and Methods: Mandibular molar teeth of 56 patients were evaluated. The mandibular molar teeth whose pulp chamber was not violated by caries, restoration, fracture crown and those having closed apex were included in the study. The intraoral periapical radiographs were taken with paralleling angle technique using radio-opaque grid with 1 mm space. This grid was placed directly on the film. Results: In 94% of the mandibular first molars specimens the pulp chamber ceiling was at the level of the cemento-enamel junction. The measurements showing the lowest percentage variance were buccal cusp to furcation (approximately 11%) and buccal cusp to pulp chamber ceiling (approximately 15%). The distance from the cusp tip to pulp chamber ceiling height was approximately 6.0 mm, the distance from the pulpal floor to the furcation was approximately 3.0 mm, and the average height of a pulp chamber was 1.5 to 2.0 mm. Conclusion: The exact knowledge of distances of pulp chamber from various anatomical landmarks helps in proper assessment of root canals and ultimately avoids the failure of root canal treatment.

• Imaging Science in Dentistry
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• 제45권2호
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• pp.95-101
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• 2015

Purpose: This study used cone-beam computed tomography (CBCT) to characterize mandibular molar root and canal morphology and its variability in Belgian and Chilean population samples. Materials and Methods: We analyzed the CBCT images of 515 mandibular molars (257 from Belgium and 258 from Chile). Molars meeting the inclusion criteria were analyzed to determine (1) the number of roots; (2) the root canal configuration; (3) the presence of a curved canal in the cross-sectional image of the distal root in the mandibular first molar and (4) the presence of a C-shaped canal in the second mandibular molar. A descriptive analysis was performed. The association between national origin and the presence of a curved or C-shaped canal was evaluated using the chi-squared test. Results: The most common configurations in the mesial root of both molars were type V and type III. In the distal root, type I canal configuration was the most common. Curvature in the cross-sectional image was found in 25% of the distal canals of the mandibular first molars in the Belgian population, compared to 11% in the Chilean population. The prevalence of C-shaped canals was 10% or less in both populations. Conclusion: In cases of unclear or complex root and canal morphology in the mandibular molars, CBCT imaging might assist endodontic specialists in making an accurate diagnosis and in treatment planning.

• 대한소아치과학회지
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• 제51권1호
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• pp.11-21
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• 2024

This study aimed to analyze the prevalence and severity of infraoccluded primary molars (IPM) and their correlation with the agenesis of permanent successors (APS). A total of 4,011 panoramic radiographs from children aged 4 to 11 years who had all 8 primary molars were examined. The prevalence of APS was analyzed based on the severity and tooth type of IPM. The prevalence of IPM was 13.0%, and there was no difference between genders. The majority of the children had two IPMs each. In all tooth types, mild infraocclusion was the most prevalent, whereas severe infraocclusion was the least frequent. Among the types of primary molars, the lower primary first molar (62.3%) was the most affected, followed by the lower primary second molar (27.7%), the upper primary second molar (5.8%), and the upper primary first molar (4.2%). Infraocclusion was 11.2 times more prevalent in the mandible than in the maxilla, with no significant difference between the left and right sides. The correlation between IPM and APS was also investigated. Among the subjects, 177 had one or more agenesis of premolars, of whom 54 (30.5%) had IPM. Additionally, among the 521 individuals with IPM, 54 individuals exhibited APS (10.4%). This study identified a noteworthy prevalence of infraocclusion, with notable variations among molar types. The LPFM was particularly affected. The majority of cases were classified as mild in severity. Furthermore, a compelling association between IPM and APS was established. Understanding this connection may enhance treatment strategies for infraoccluded teeth and tooth agenesis.

• 대한소아치과학회지
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• 제51권1호
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• pp.99-108
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• 2024

Early loss of the primary maxillary second molar can lead to complications in which mesial drift of the adjacent first molar (M1) can disturb eruption of the succedaneous second premolar (P2). This study reports two cases of space loss for P2 caused by early exfoliation of its predecessor. After the eruption of the first premolar, the Jones jig appliance was used to distalize M1 and regain space for the eruption of P2. The appliance was further utilized to align the palatally erupted P2 into the dental arch. In both cases, the space and corrected position of P2 were well maintained. Early exfoliation of the primary second molar caused by mesial encroachment of M1 is a common phenomenon, and pediatric dentists should attend to this during routine examinations. An appropriate intervention should be initiated when the primary second molar is lost during the mixed dentition period. If used with careful anchorage control, the Jones jig appliance can effectively resolve this problem.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.1.1-1.4
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• 2016

Background: This study aimed to investigate the distribution and prevalence of intraosseous loop (anastomosis between posterior superior alveolar artery and infraorbital artery) in Koreans detected on computed tomography (CT) images taken prior to sinus augmentation surgery. Methods: From the 177 patients who underwent sinus augmentation with lateral approach at Ewha Womans University Department of Implant Dentistry, 284 CT scans were evaluated. The canal height (CH), ridge height (RH), and canal height from the sinus floor (CHS) were measured on para-axial views at the first premolar, first molar, and second molar. The horizontal positions of the bony canals in the lateral wall were also classified. One-way analysis of variance (ANOVA) and t test were used to estimate the statistical differences (p < 0.05). Results: The intraosseous loops were detected in 92 CT scans (32 %). The mean vertical height of the bony canals from the alveolar crest (CH) was $23.45{\pm}2.81$, $15.92{\pm}2.65$, and $16.61{\pm}2.92mm$ at the second premolar, first molar, and second molar, respectively. In the horizontal positions of the bony canals, intraosseous type was the most predominant. The canal heights more than 15 mm and less than 17 mm were most prevalent (33.7 %) and those under 13 mm were 12.0 %. Conclusions: The radiographic findings in this study could be used to decide the lateral osteotomy line avoiding potential vascular complication. However, only one third of the canals could be detected in CT scans; a precaution should be taken for the possibility of severe bleeding during lateral osteotomy.

• 대한치과교정학회지
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• 제46권2호
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• pp.96-103
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• 2016

Objective: To compare the transverse dental changes induced by the palatally applied Frog appliance and buccally applied Karad's integrated distalizing system (KIDS). Methods: We evaluated the pre- and post distalization orthodontic models of 39 patients, including 19 treated using the Frog appliance, which is palatally positioned (Frog group), and 20 treated using KIDS, which is buccally positioned (KIDS group). Changes in intermolar and interpremolar distances and the amount of maxillary premolar and molar rotation were evaluated on model photocopies. Wilcoxon and Mann-Whitney U tests were used for statistical evaluations. A p-value of < 0.05 was considered statistically significant. Results: Significant distopalatal rotation of premolars and distobuccal rotation of molars were observed in Frog group (p < 0.05), while significant distopalatal rotation of molars (p < 0.05), with no significant changes in premolars, was observed in KIDS group. The amount of second premolar and first molar rotation was significantly different between the two groups (p < 0.05 and p < 0.001, respectively). Furthermore, expansion in the region of the first molars and second premolars was significantly greater in KIDS group than in Frog group (p < 0.001 for both). Conclusions: Our results suggest that the type and amount of first molar rotation and expansion vary with the design of the distalization appliance used.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제44권4호
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• pp.167-173
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• 2018

Objectives: Classification of the degree of postoperative nerve damage according to contact with the mandibular canal and buccal cortical bone has been studied, but there is a lack of research on the difference in postoperative courses according to contact with buccal cortical bone. In this study, we divided patients into groups according to contact between the mandibular canal and the buccal cortical bone, and we compared the position of the mandibular canal in the second and first molar areas. Materials and Methods: Class III patients who visited the Dankook University Dental Hospital were included in this study. The following measurements were made at the second and first molar positions: (1) length between the outer margin of the mandibular canal and the buccal cortical margin (a); (2) mandibular thickness at the same level (b); (3) Buccolingual $ratio=(a)/(b){\times}100$; and (4) length between the inferior margin of the mandibular canal and the inferior cortical margin. Results: The distances from the canal to the buccal bone and from the canal to the inferior bone and mandibular thickness were significantly larger in Group II than in Group I. The buccolingual ratio of the canal was larger in Group II in the second molar region. Conclusion: If mandibular canal is in contact with the buccal cortical bone, the canal will run closer to the buccal bone and the inferior border of the mandible in the second and first molar regions.

• 대한소아치과학회지
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• 제51권3호
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• pp.279-289
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• 2024

This study aimed to identify the clinical characteristics of molar root-incisor malformation (MRIM) and provide clinical considerations for treatments. Panoramic radiographs and electronic medical records of 64 patients with MRIM were retrospectively reviewed. Age, gender, follow-up period, medical history, complications, distribution of MRIM teeth, treatment, and prognosis were analyzed. Females were affected 1.56 times more than males, and the average age was 8.2 years. Dental complications, including periapical lesions, abscesses, and alveolar bone loss, were observed in 71.9%, and eruption disturbance of adjacent teeth was noticed in 37.5%. Most patients had medical histories in the first year of life. The most prevalent history was prematurity or low birthweight, followed by neurological conditions, surgeries, medications, and infections. All patients had MRIM on permanent first molars. The primary second molars were the second most frequently involved, followed by maxillary permanent central incisors and primary first molars. The prevalence was low on permanent lateral incisors and canines. Extraction was the most prevalent treatment done on MRIM-affected teeth, and most extraction sockets were managed by the eruption of permanent second molars. Few cases received endodontic treatment but with low success rates. Early detection of MRIM and prompt, appropriate treatment are important to avoid unnecessary discomfort from complications.

• 대한치과교정학회지
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• 제22권3호
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• pp.579-589
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• 1992

Non-steroidal anti-inflammatory agents are used to relieve pain and to reduce swelling in dental clinics. This experiment was performed to study the effect of non-steroidal anti-inflammatory agents in Sprague-Dawley rats on orthodontic tooth movement. Thirty rats were used and divided six groups of five rats each. The first group, administered saline and no orthodontic force, served as a normal group. The second group, administered saline and applied experimental force, was control group. The other four groups were administered Aspirin, Pontal, Tyrenol and Indomethacin each, and applied experimental orthodontic force by 1/4 inch elastic, inserted into the interproximal space between maxillary first and second molar in rats. All experimental rats were sacrificed after three days, and the specimens were sectioned horizontally five times serially, and counted the number of osteoclasts appeared at the compressed surface of interradicular bone on first buccal root of first molar on light microscope. The obtained results were as follows: 1. The number of osteoclast on the compressed surface of the interradicular bone on first buccal root of the first molar in the four non-steroidal anti-inflammatory agents groups decreased in contrast to control group. 2. In non-steroidal anti-inflammatory agents group, the number of osteoclast in Indomethacin group was least among the all non-steroidal anti-inflammatory agents groups. From the above results, it was believed that the non-steroidal anti-inflammatory agents may have the inhibitory effect of tooth movement during orthodontic treatment.