청소년 환자에서 상악전치 발치 후 치조제 보존술에 관한 증례보고

정연화,김형태,이창섭,이상호 朝鮮大學校 口腔生物學硏究所 1998 口腔生物學硏究 Vol.22 No.2

Extraction socket with destroyed buccal plate often resulted in localized ridge deformities in healing process. The main problem of localized anterior ridge deformities was esthetic one. Ideally, the defects should be prevented form occurring. Using the principles of guided bone regeneration, a ridge preservation technique with subepithelial connective tissue graft was described that could be applied to post-extraction siters for preventing localized ridge deformities.

Analysis of the root position and angulation of maxillary premolars in alveolar bone using cone-beam computed tomography

정연화,조봉혜,황재준 대한영상치의학회 2022 Imaging Science in Dentistry Vol.52 No.4

Purpose: This study investigated whether the relationship between the maxillary sinus and the root of the maxillary premolar is correlated with the root position and whether there is a difference in the long axis angle of premolars and the buccal bone thickness according to the sinus-root relationship and root position. Materials and Methods: Cone-beam computed tomographic images of 587 maxillary first premolars and 580 second premolars from 303 patients were retrospectively reviewed. The maxillary sinus floor-root relationship was classified into 4 types, and the root position in the alveolar bone was evaluated as buccal, middle, or palatal. The long axis angle of the maxillary premolars in the alveolar bone and the buccal bone thickness were measured. The correlation between these parameters was analyzed. Results: The maxillary sinus floor-root relationship showed a statistically significant correlation with the root position in the alveolar bone. Most maxillary first premolars were buccally located, and more than half of the second premolars had their roots in the middle. The long axis angle of the premolars was significantly larger in buccal-positioned teeth than in middle-positioned teeth, and the buccal bone was thinner. Conclusion: When the root of the maxillary premolar was separated from the sinus floor, the premolar was often located on the buccal side. Most of the maxillary first premolars had a thinner buccal bone and larger inclination than the second premolars. It is recommended to evaluate the root position, sagittal angle and buccal bone thickness using CBCT for implant treatment planning.

KAAV 해수추진 전향기 품질향상을 위한 개선연구

정연화,박태완,이영준,김성훈 국방기술품질원 2022 국방품질연구논집 Vol.4 No.1

In this paper, we analyze the operating principle and problems to solve the frequently occurring quality problems of the seawater propulsion direction changing device of the KAAV and suggest improvements. By applying the improvements, the amplifier and detector were redesigned, a prototype was made and performance tests, environmental tests, system installation tests, and operation tests were performed. As a result, all problems were resolved.

Periapical multilocular osteoporotic bone marrow defect

정연화,조봉혜,나경수 대한영상치의학회 2005 Imaging Science in Dentistry Vol.35 No.4

A case of osteoporotic bone marrow defect, which appeared as a well-defined multilocular radiolucency overlapping the roots of mandibular right second molar, was reported. On periapical radiograph, a daughter cyst-like radiolucency was seen at the anterior margin of the lesion making it difficult to rule out odontogenic keratocyst

The location of the mandibular canal in prognathic patients compared to subjectswith normal occlusion

정연화,나경수,조봉혜 대한영상치의학회 2007 Imaging Science in Dentistry Vol.37 No.4

Purpose: The purpose of this study was to compare the location of the mandibular canal in Class III malocclusionto its location in normal occlusion for adults.Materials and Methodsmeasurements were taken on cross sectional tomography between the first and second molars: the distance from themandibular canal to the inner surface of both the buccal and lingual cortices, the distance from the mandibular canalto the inferior border of the mandible, and the buccolingual width of the mandible. The buccolingual location of thecanals was classified as lingual, central, or buccal. Each measurement was analyzed with an independent ttest tocompare Class III malocclusion to normal occlusion. Results: Compared to the control group, the prognathic group had a shorter distance from the canal to the innergually in the prognathic group.Conclusion : This study showed that the mandibular canal was located more lingually and inferiorly in prognathicpatients than in patients with normal occlusion. These results could help surgeons to reduce injuries to the inferioralveolar nerve.(Korean J Oral Maxillofac Radiol 2007; 37 : 217-20)

Radiographic evaluation of third molar development in 6- to 24-year-olds

정연화,조봉혜 대한영상치의학회 2014 Imaging Science in Dentistry Vol.44 No.3

Purpose: This study investigated the developmental stages of third molars in relation to chronological age and compared third molar development according to location and gender. Materials and Methods: A retrospective analysis of panoramic radiographs of 2490 patients aged between 6 and 24 years was conducted, and the developmental stages of the third molars were evaluated using the modified Demirjian’s classification. The mean age, standard deviation, minimal and maximal age, and percentile distributions were recorded for each stage of development. A Mann-Whitney U test was performed to test the developmental differences in the third molars between the maxillary and mandibular arches and between genders. A linear regression analysis was used for assessing the correlation between the third molar development and chronological age. Results: The developmental stages of the third molars were more advanced in the maxillary arch than the mandibular arch. Males reached the developmental stages earlier than females. The average age of the initial mineralization of the third molars was 8.57 years, and the average age at apex closure was 21.96 years. The mean age of crown completion was 14.52 and 15.04 years for the maxillary and the mandibular third molars, respectively. Conclusion: The developmental stages of the third molars clearly showed a strong correlation with age. The third molars developed earlier in the upper arch than the lower arch; further, they developed earlier in males than in females.

물체 윤곽의 유형과 물체-사선 간 거리가 포겐도르프 착시에 미치는 영향

정연화 충북대학교 인간심리연구소 2018 인간심리연구 Vol.2 No.2

본문 참고

Prevalence of missing and impacted third molars in adults aged 25 years and above

정연화,조봉혜 대한영상치의학회 2013 Imaging Science in Dentistry Vol.43 No.4

Purpose: The purpose of this study was to determine the prevalence of missing and impacted third molars in people aged 25 years and above. Materials and Methods: The study sample of 3,799 patients was chosen randomly from patients who visited Pusan National University Dental Hospital and had panoramic radiographs taken. The data collected included presence and impaction state, angulation, and depth of impaction of third molars, and radiographically detected lesions of third molars and adjacent second molars. Results: A greater percentage of men than women retained at least one third molar. The incidence of third molars decreased with increasing age. The incidence of partially impacted third molars greatly declined after the age of 30. Vertically impacted maxillary third molars and horizontally impacted mandibular third molars were most frequent in all age groups. Among the maxillary third molars, those impacted below the cervical line of the second molar were most frequent in all age groups, and among the mandibular third molars, deeply impacted third molars were most frequent in those aged over 40. Dental caries was the most common radiographic lesion of the third molars. Mesioangularly impacted third molars showed radiographic lesions in 13 (9.5%) adjacent maxillary second molars and 117 (27.4%) mandibular second molars. Conclusion: The number of remaining third molars decreased and the percentage of Class C depth increased with age. Caries was the most frequent lesion in third molars. Partially impacted mesioangular third molars showed a high incidence of caries or periodontal bone loss of the adjacent second molar. Regular oral examination will be essential to keep asymptomatic third molars in good health.

Correlation of panoramic radiographs and cone beam computed tomography in the assessment of a superimposed relationship between the mandibular canal and impacted third molars

정연화,나경수,조봉혜 대한영상치의학회 2012 Imaging Science in Dentistry Vol.42 No.3

Purpose: This study evaluated the association between cone beam computed tomography (CBCT) and panoramic radiographs in the assessment of a superimposed relationship between the mandibular canal and impacted third molars. Materials and Methods: The study samples consisted of 175 impacted third molars from 131 patients who showed a superimposed relationship between the mandibular canal and third molars on panoramic radiographs and were referred for the examination of the mandibular canal with CBCT. Panoramic images were evaluated for the darkening of the root and the interruption of the mandibular canal wall. CBCT images were used to assess the buccolingual position of the mandibular canal relative to the third molar, the proximity of the roots to the canal, and lingual cortical bone loss. The association of the panoramic and CBCT findings was examined using a Chi-square test and Fisher’s exact test. Results: Panoramic radiographic signs were statistically associated with CBCT findings (P⁄0.01). In cases of darkening roots, lingual cortical bone loss or buccally positioned canals were more frequent. In cases in which the mandibular canal wall was interrupted on panoramic radiographs, contact or lingually positioned canals were more frequent. Conclusion: The results of this study suggest that contact between the mandibular third molar and canal and a lingually positioned canal could be more frequently observed in cases of the interruption of the white line of the mandibular canal and that there could be more lingual cortical loss in cases of darkening roots. Purpose: This study evaluated the association between cone beam computed tomography (CBCT) and panoramic radiographs in the assessment of a superimposed relationship between the mandibular canal and impacted third molars. Materials and Methods: The study samples consisted of 175 impacted third molars from 131 patients who showed a superimposed relationship between the mandibular canal and third molars on panoramic radiographs and were referred for the examination of the mandibular canal with CBCT. Panoramic images were evaluated for the darkening of the root and the interruption of the mandibular canal wall. CBCT images were used to assess the buccolingual position of the mandibular canal relative to the third molar, the proximity of the roots to the canal, and lingual cortical bone loss. The association of the panoramic and CBCT findings was examined using a Chi-square test and Fisher’s exact test. Results: Panoramic radiographic signs were statistically associated with CBCT findings (P⁄0.01). In cases of darkening roots, lingual cortical bone loss or buccally positioned canals were more frequent. In cases in which the mandibular canal wall was interrupted on panoramic radiographs, contact or lingually positioned canals were more frequent. Conclusion: The results of this study suggest that contact between the mandibular third molar and canal and a lingually positioned canal could be more frequently observed in cases of the interruption of the white line of the mandibular canal and that there could be more lingual cortical loss in cases of darkening roots.

Assessment of maxillary third molars with panoramic radiography and cone-beam computed tomography

정연화,조봉혜 대한영상치의학회 2015 Imaging Science in Dentistry Vol.45 No.4

Purposes: This study investigated maxillary third molars and their relation to the maxillary sinus using panoramic radiography and cone-beam computed tomography (CBCT). Materials and Methods: A total of 395 maxillary third molars in 234 patients were examined using panoramic radiographs and CBCT images. We examined the eruption level of the maxillary third molars, the available retromolar space, the angulation, the relationship to the second molars, the number of roots, and the relationship between the roots and the sinus. Results: Females had a higher frequency of maxillary third molars with occlusal planes apical to the cervical line of the second molar (Level C) than males. All third molars with insufficient retromolar space were Level C. The most common angulation was vertical, followed by buccoangular. Almost all of the Level C molars were in contact with the roots of the second molar. Erupted teeth most commonly had three roots, and completely impacted teeth most commonly had one root. The superimposition of one third of the root and the sinus floor was most commonly associated with the sinus floor being located on the buccal side of the root. Conclusions: Eruption levels were differently distributed according to gender. A statistically significant association was found between the eruption level and the available retromolar space. When panoramic radiographs showed a superimposition of the roots and the sinus floor, expansion of the sinus to the buccal side of the root was generally observed in CBCT images.