• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.3
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• pp.284-291
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• 2016

In order to provide a diagnostic basis for predicting the possibility of the self-correction of ectopic first permanent molars, differences among normal eruption, reversible and irreversible ectopic eruption of maxillary first permanent molars were retrospectively analyzed. The angles of the long axes and the occlusal lines between the maxillary first permanent molar and the adjacent tooth were measured by panoramic radiographs. The occlusal relationship of second primary molars was also investigated. There is a statistically significant difference between the ectopic eruption group and normal group (p < 0.05), but not between the reversible and irreversible ectopic eruption groups (p > 0.05). The angles between the second primary molar and the first permanent molar, the second primary molar and the second permanent molar in ectopic groups showed a smaller degree than those of the control group. Mesial step was found more frequently in the ectopic eruption group than the normal group. In conclusion, the angulation of the first permanent molar and tooth germ of the maxillary second permanent molar showed close relation with ectopic eruption of the maxillary first permanent molar and ectopic first permanent molar is likely to occur in class III patients with maxillary deficiency.

• Journal of Oral Medicine and Pain
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• v.20 no.1
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• pp.141-158
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• 1995

This study was performed to invetigate the relationship between clinical manifestations related to temporomandibular joint sounds and temporomandibular joint vibrations that occurred synchronously with sounds. There have been reported in many articles that joint sounds indicate internal joint pathology. Therefore, it is necessary to evaluate type and patterns of joint sounds, and radiographic changes of temporomandibular joint(TMJ) in order to diagnose and deal with the Temporomandibular Disorders(TMD). For this study 142 patients with TMDs were collected and they were examined by routine diagnostic procedure for TMDs. The author classified TMJ sounds clinically into 3 types : click, popping, and crepitus. Transcranial and panoramic radiographs were taken for observein bony changes of TMJ, and for observing vibrations of TMJ Sonopak of Biopak system was used. The obtained results were as follows : 1. Female subjects with crepitus were older than those with click or popping and their mean ages were about 45 years old. But in male subjects, there was no age difference. 2. For all subjects, mean value of maximal mouth opening were above 40mm, which are lower limit of normal vertical opening. But in subjects with L-type opening deviation, mouth opening capacity were about 36mm of range. 3. Symptom duration stated when patient presented first were slightly longer in subjects with crepitus but there were no statistical differences. And there were also no radiographic differences among 3 types of joint sounds in regard to symptom duration. 4. In subjects wih click, it might have been interpreted that 12% had closed lock, 12% had degenerative joint disease, and about 17% of he subjects had normal joints by Sonopak. 5. There were no significant relationships between subjective loudness of joint sounds and magnitude of joint vibrations. 6. The highest value of Integral and peak amplitude were observed in popping sounds and though it was not significant, value of peak frequency was highest in crepitus. 7. Amount of mandibular positional change were differed between click and crepitus on frontal plane, between click, crepitus and popping on horizontal plane in rotational movement, respectively. However, there no difference among them in translational movements.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.5
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• pp.276-283
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• 2012

Objectives: Curettage and enucleation are two of the most common procedures performed in oral and maxillofacial surgery units. To access a cystic lesion, the buccal cortical plate is removed. The no reposition (NR) group underwent surgery without repositioning the buccal cortical plate. The reposition (R) group underwent surgery with a repositioning of the buccal cortical plate. This study compared the two surgical procedures in terms of bone healing and complications. Materials and Methods: Patients who underwent curettage and enucleation surgery were enrolled in this study. Panoramic radiographs of the patients in both the NR group (n=26) and R group (n=34) were taken at the baseline and at 6, 12 and 24 months after surgery. The radiolucent area was calculated to evaluate bony healing in each radiograph. The complications were analyzed through a review of the medical records. Results: The correlation between bony healing and surgical approach was not significant in the 6th, 12th, and 24th month (P<0.05). The complication rate was not associated with gender, graft material, bone graft and drain insertion (P<0.05). On the other hand, the R group had a higher complication rate (35.3%) than the NR group (0%). The difference in the mean lesion size between the NR group ($37,024{\pm}3,617$ pixel) and R group ($92,863{\pm}15,931$ pixel) was significant (independent t test, P=0.004). Conclusion: Although the reposition method is chosen when the lesion size is large, it is associated with more complications. Indeed, infection, discomfort and recurrence of the lesion were the most common complications in the R group. Furthermore, the R method does not have a strong point in terms of bone healing compared to the NR method. Therefore, the R method cannot be considered an ideal approach and should be used in limited cases.

• Journal of Periodontal and Implant Science
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• v.49 no.6
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• pp.382-396
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• 2019

Purpose: The purpose of this study was to elucidate the efficacy and safety of carbonate apatite (CO₃Ap) granules in 2-stage sinus floor augmentation through the radiographic and histomorphometric assessment of bone biopsy specimens. Methods: Two-stage sinus floor augmentation was performed on 13 patients with a total of 17 implants. Radiographic assessment using panoramic radiographs was performed immediately after augmentation and was also performed 2 additional times, at 7±2 months and 18±2 months post-augmentation, respectively. Bone biopsy specimens taken from planned implant placement sites underwent micro-computed tomography, after which histological sections were prepared. Results: Postoperative healing of the sinus floor augmentation was uneventful in all cases. The mean preoperative residual bone height was 3.5±1.3 mm, and this was increased to 13.3±1.7 mm by augmentation with the CO₃Ap granules. The mean height of the augmented site had decreased to 10.7±1.9 mm by 7±2 months after augmentation; however, implants with lengths in the range of 6.5 to 11.5 mm could still be placed. The mean height of the augmented site had decreased to 9.6±1.4 mm by 18±2 months post-augmentation. No implant failure or complications were observed. Few inflammatory cells or foreign body giant cells were observed in the bone biopsy specimens. Although there were individual differences in the amount of new bone detected, new bone was observed to be in direct contact with the CO₃Ap granules in all cases, without an intermediate layer of fibrous tissue. The amounts of bone and residual CO₃Ap were 33.8%±15.1% and 15.3%±11.9%, respectively. Conclusions: In this first demonstration, low-crystalline CO₃Ap granules showed excellent biocompatibility, and bone biopsy showed them to be replaced with bone in humans. CO₃Ap granules are a useful and safe bone substitute for two-stage sinus floor augmentation.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.4
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• pp.389-396
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• 2020

A pyramidal molar is which has completely fused roots with a solitary enlarged canal. The purpose of this retrospective study was to assess the prevalence and characteristics of pyramidal molars among adolescent. A total of 1,612 patients' panoramic radiographs were screened. A total of 12,896 first and second molars were evaluated. The relative incidence and the correlations regarding the location of pyramidal molar (maxillary versus mandibular) and gender were analyzed using the chi-square test. The overall incidence of patients with pyramidal molars was 1.49%. 24 patients were found to have a pyramidal molar and it was more prevalent in women (18 women and 6 men). The prevalence of pyramidal molars from all first and second molars examined was 0.31%. 88 percent of pyramidal molars occurred in maxilla. All pyramidal molars were second molar. Pyramidal molar has a relatively poor periodontal prognosis compared with common multi-rooted teeth and it is important to understand the structural characteristics of root canal during pulp treatment. Clinicians should be able to understand the anatomical properties of pyramidal molar and apply it to treatment and prognostic evaluation.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.4
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• pp.274-282
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• 2013

The goal of this study was to analyze prevalence and distribution of congenitally missing teeth in 3302 patients from 7 to 15 years old, who had visited and taken panoramic radiographs at the Department of Pediatric Dentistry, from January 2008 to December 2012. The prevalence of hypodontia in the males (5.9%) was slightly higher than in the females (4.7%). In the affected patients, the mean number of congenitally missing teeth in the mandible was statistically higher than in the maxilla (p < 0.05). However, there was no significant difference in the number of congenitally missing teeth between left and right dentitions (p > 0.05). Excluding the Mn. third molars, the most frequent congenitally missing teeth site was the Mn. second premolars. In contrast, the most infrequent congenitally missing teeth sites were the Mx. and Mn. first premolars, and Mx. central incisors. The bilateral combination or antagonistic quadrants combination of congenitally missing teeth in hypodontia patients was 80.3%. The result of this study will contribute to clinicians to make accurate diagnosis and establish favorable treatment plans, by offering invaluable data about the number and distribution of congenitally missing teeth.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.1
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• pp.91-98
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• 2006

Supernumerary teeth are teeth which result from the continued budding of the enamel organ of the preceding tooth or from excessive proliferation of cells. They are most often found in the maxillary anterior region. And they can be responsible for a variey of irregularities in the primary and transitional dentition. There are two morphological types of supernumerary teeth, supplemental and rudimentary. Supplemental teeth have normal shape and size. In contrast, rudimental teeth have abnormal shape and smaller size. Supplemental supernumerary teeth are most common in permanent lateral incisor area. Its extraction must be decided more carefully with differential diagnosis between normal teeth, because it has normal shape and size. We reports 3 cases of the normal incisor shaped teeth in the maxillary anterior region. In all cases, we used the 3D Dental-CT as well as the conventional plain film such as periapical, occlusal, and panoramic radiograph. Consequently, 3B Dental-CT was valualble to figure out the exact position and morphology of supernumerary teeth, to do more conservative surgery and to reduce surgery stress and time.

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.2
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• pp.144-150
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• 2015

Early treatment is recommended for class III malocclusion in the primary dentition, though it is difficult to diagnose correctly. It was recommended dental maturation can possibly be used to make a differential diagnosis of skeletal class III malocclusion. This study aimed to compare dental maturation of first molars in children with skeletal or non-skeletal class III malocclusion in the primary dentition and to determine if dental maturation could be used to make a differential diagnosis of class III malocclusion. Among the children visiting the department of pediatric dentistry in Pusan National University Dental Hospital for anterior crossbite in the primary dentition, 18 were categorized into the non-skeletal class III malocclusion and 34 into the skeletal class III malocclusion. Panoramic radiographs were used to make comparative analysis of dental age and the eruption rate of the first molars. The following results were obtained. No difference was found between chronologic and dental age by the skeletal features or gender, with the latter being older than the former (p < 0.05). The discrepancies in eruption rate of first molars were significantly different between skeletal (18.91%) and non-skeletal groups (16.53%) (p < 0.05). This result implies that maturation of the first molars might be used to make a differential diagnosis of class III malocclusion.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.3
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• pp.241-246
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• 2014

The purpose of this study was to find out prevalence of peg-laterals and to evaluate the frequency of dental anomalies in Korean children with peg-laterals. For this study, panoramic radiographs of 3,278 patients (aged 7 to 15 years) from the Department of Pediatric Dentistry admitted from January, 2008 to January, 2013 were selected for an investigation on peg-laterals distribution. The prevalence of peg-laterals was 2.62% (86 subjects). Among the peg-laterals children, the distribution of associated dental anomalies were as follows: congenitally missing teeth (29.1%), dens invaginatus (19.8%), impacted teeth (12.8%), supernumerary teeth (9.3%), and transposition (4.7%). Due to this study showing frequent occurrences of peg-laterals with other dental anomalies, one suggestion is to consider such relationships before deciding on a diagnosis and treatment plan.

• Journal of Periodontal and Implant Science
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• v.37 no.2
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• pp.277-286
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• 2007

The edentulous posterior maxilla generally provides a limited amount of bone height because of atrophy of the ridge and pneumatization of the maxillary sinus, Maxillary sinus augmentation is one of the surgical techniques for reconstruction of the severely resorbed posterior maxilla. The purpose of this study was to evaluate the survival rate of implants and the long-term changes of graft height after maxillary sinus augmentation by lateral window approach. From September 1996 to July 2004, maxillary sinus augmentation with mixed grafts of autograft, allograft, xenograft and alloplast were performed on 45 patients and 100 implants were placed. We evaluated the survival rate of implants and the changes of BL(bone length)/IL(implant length) according to time using panoramic radiographs. The survival rate of implants was 91.0% for follow-up period. The mean reduction of graft heights was 0.34mm(3.0%) for 6 months and 1.22mm(1O.66%) for 3 years after augmentation. The total mean BL/IL was $1.34{\pm}0.21$ during 5 year observation period after augmentation and decreased slightly over time. The result means that graft materials were stable above the implant apex. BL/ILs of 1stage procedure were significantly decreased at 1-2 year, 3-4 year after augmentation and no statistically significant changes were observed in those of 2 stage procedure. The graft materials of both procedures were stable above the implant apex. No statistically significant changes of BL/IL were observed in the grafts combined with low amount of autogenous bone or without autogenous bone. The graft materials of both groups were stable above the implant apex. The results indicated that the placement of dental implants with maxillary sinus augmentation showed predictable clinical results and the grafts combined with low amount of autogenous bone or without autogenous bone had long-term resistance to resorption in maxillary sinus.