• 대한치과교정학회지
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• 제15권1호
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• pp.67-74
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• 1985

The primary objective of this study is to make the prediction percentile tabulation of the sun of mesiodistal width of the unerupted permanent canines and premolars derived from the sum of mesiodistal width of the erupted permanent mandibular incisors in Korean population. The subjects were 316 individuals with normal occlusion aged 11 to 23 years. The sum of mesiodistal width of mandibular incisors, and the sum of mesiodistal width of maxillary canine, first and second premolars, and the sum of mandibular canine, first and second premolars were measured from the dental cast models using the sliding caliper (Mitutoyo Co.). From the study, the results are as follows: 1. The sum of M-D width of mandibular incisors and the sum of M-D width of maxillary canines, first and second premolars, and the sum of M-D width of mandibular canine, first and second premolars were smaller than those of American Caucasians and Negros. 2. The correlation coefficient between the sum of M-D width of mandibular incisors and that of maxillary or mandibular canines, first and second premolars was found to be 0.598 and 0.586, respectively. 3. The regression constants were determined to evaluate the sum of M-D width of the unerupted permanent canines and premolars derived from the sum of M-D width of the erupted permanent incisors. 4. The prediction percentile tabulation were made in an attempt to predict the total M-D width of the unerupted permanent canines and premolars derived from the total M-D width of the erupted permanent mandibular incisors.

• 대한소아치과학회지
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• 제45권4호
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• pp.484-491
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• 2018

선천적 치아의 결손은 비교적 흔한 치아 발육장애이며 하악 제2소구치의 결손은 치아 결손 중 가장 많이 나타나는 것으로 알려져 있다. 이 연구의 목적은 하악 제2소구치 결손과 연관되어 나타나는 다른 치아의 결손 및 치아의 발육 지연에 대해 조사하는 것이다. 이 연구는 2014년부터 2016년까지 연세대학교 치과대학을 내원하여 파노라마 방사선을 찍은 만 9세-15세의 소아청소년 중 하악 제2소구치 결손이 있는 환자를 대상으로 시행되었다. 하악 제2소구치의 결손을 가진 125명의 환자들 중 다른 치아의 결손은 58명(46.4%)에서 나타났으며 발육이 지연된 치아는 38명(30.4%)에서 나타났다. 이번 연구에서 하악 제2소구치의 결손을 가진 환자는 그렇지 않은 어린이와 비교하였을 때 치아 결손 및 치아 발육지연의 유병률이 높게 나타났다.

• 대한치과교정학회지
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• 제11권2호
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• pp.143-150
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• 1981

Casts of 180 Korean male and female with normal occulsion of early permanent dentition (from dental age of Hellman III C, to IV A) were studied to measure the mesiodistal crown diameters and to calculate the coefficients of correlation between the teeth. From the study, the following conclusions were made: 1. Mesiodistal dimension of maxillary central incisors, canines, first molars and mandibular canines, first premolars, second premolars and first molars of male are larger than that of female. 2. Korean teeth are roughly intermediate between those of American Caucasian and those of American Negro. 3. In both sexes, the relation between the first and second premolars appeared highly correlated not only in the maxillary arch but also in the mandibular arch, and the relation between the central incisor and lateral incisor appeared highly correlated in the mandibular arch. 4. The relation between the maxillary and mandibular first premolars appeared highly correlated in both sex, and the relation between the maxillary canine and mandibular canine in male as well as between the maxillary central incisor and mandibular central incisor in female appeared highly correlated.

• Restorative Dentistry and Endodontics
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• 제47권1호
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• pp.1.1-1.13
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• 2022

Objectives: This study assessed the shape and anatomical relationship of the mental foramen (MF) to mandibular posterior teeth in an Indian sub-population. Materials and Methods: In total, 475 existing cone-beam computed tomography records exhibiting 950 MFs and including the bilateral presence of mandibular premolars and first molars were assessed. Images were evaluated 3-dimensionally to ascertain the position, shape, and anatomical proximity of MFs to mandibular teeth. The position and shape of MFs were measured and calculated. The Pythagorean theorem was used to calculate the distance between the root apex of the mandibular teeth and the MF. Results: MFs exhibited a predominantly round shape (left: 67% and right: 65%) followed by oval (left: 30% and right: 31%) in both males and females and in different age groups. The root apices of mandibular second premolars (left: 71% and right: 62%) were closest to the MF, followed by distal to the first premolars and mesial to the second premolars. The mean vertical distance between the MF and the nearest tooth apex calculated on sagittal sections was 2.20 mm on the right side and 2.32 mm on the left side; no significant difference was found according to sex or age. The distance between the apices of the teeth and the MF was ≥ 4 mm (left; 4.09 ± 1.27 mm and right; 4.01 ± 1.15 mm). Conclusions: These findings highlight the need for clinicians to be aware of the location of the MF in treatment planning and while performing non-surgical and surgical endodontic procedures.

• 디지털융복합연구
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• 제20권2호
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• pp.317-323
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• 2022

본 연구는 3차원 가상모형을 이용하여 하악 제2소구치 교두 변이 양상을 정성적으로 분석하고, 교두 변이에 따른 치아 표면적의 정량적 분석과 함께 좌·우측 대칭성을 분석하고자 하였다. 127개의 하악 제2소구치 가상치아를 준비한 후, RapidForm2004(INUS technology INC, Seoul, Korea)을 이용하여 각 교두의 절대적/상대적 단면적, 전체 치관 단면적, 교합면의 중심구 형태 등을 분석하였다. 통계방법은 Independent t-test, Kruskal-Wallis test 및 교차분석을 시행하였다. 연구 결과, 중심구의 형태는 양측간 높은 대칭성을 보였다. 좌측에서 U 형태이면 우측도 100.0% U 형태를 나타냈으며, 나머지 H 형태와 Y 형태는 각각 73.7%, 78.9% 비율로 양측간 동일한 중심구 형태를 나타냈다(p<.001). 본 연구에서 얻은 결과는 CAM/CAM을 이용한 보철물 제작 시 참고자료로 활용이 가능할 것이며, 향후 맹출 직후의 하악 제2소구치를 포함한 더 많은 샘플을 대상으로 한 후속연구가 이루어지기를 기대한다.

• 대한치과교정학회지
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• 제11권1호
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• pp.31-34
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• 1981

A study of a sample of 81 Korean adolescents was taken to determine the degree of correlation between mandibular anterior teeth size and the size of the canines and premolars. The correlation between the total mesiodistal width of the mandibular permanent incisors and that of maxillary or mandibular canine and first and second premolars was found to be 0.53 and 0.58, respectively. Further , regression constants were determined in an attempt to estimate the buccal segments from the mandibular incisors.

• Restorative Dentistry and Endodontics
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• 제7권1호
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• pp.41-45
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• 1981

A 19-year-old Korean woman presented with left mandibular dental pain and swelling. Periapical radiolucencies were associated with the mandibular left first molar, second molar and the mandibular right second molar. The mandibular right second molar root developed incompletely and has the open apex. Clinical examination revealed worn accessory occlusal cusps of premolars. A diagnosis of dens evaginatus with associated periapical lesion secondary to pulpal necrosis was made. The root canal of the lower right second premolar was sealed with Calcium hydroxide paste for apexification. About two months later Calcium hydroxide paste was removed and the canal was resealed with new Calcium hydroxide paste. After four months the canal was sealed permanently with guttapercha and zinc oxide-eugenol sealer. The root canals of the lower left premolars were irrigated every week with 3.5% NaOCl solution for and half month. And the canals were sealed with gutta-percha and ZOE sealer. Preventive endodontic treatment for the lower right first premolar was undertaken.

• 대한소아치과학회지
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• 제8권1호
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• pp.21-24
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• 1981

The author observed a case of ectopic erupted maxillary second premolars and impacted mandibular second premolars due to premature loss of the primary second molars. The treatments were done as follows: 1. In the maxilla, the teeth arrangement problem was corrected with removal of the ectopic erupted second premolars. 2. In the mandible, normal dentition was established with surgical removal of the left second premolar and removal of the permanent first molar in right side combined by orthodontic therapy.

• 대한소아치과학회지
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• 제28권3호
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• pp.369-373
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• 2001

하악 제2소구치의 선천결손은 비교적 흔히 나타나는 이상으로, 방사선사진에서 결손으로 확인되는 경우 여러가지 치료방법을 고려할 수 있다. 환자의 연령, 제2유구치 치근의 흡수상태, 총생의 정도, 악골의 성장, 측모의 형태, 절치의 돌출도, 하안 모고경 등을 고려하여 치료방법을 선택하게 된다. 그러나, 선천결손의 진단과 치료방법의 결정에 있어서 주의해야 할 점이 있다. 하악 제2소구치는 분화와 석회화과정에 있어서 가장 많은 변이를 보이는 치아이다. 경조직 형성은 $2\frac{1}{4}\sim2\frac{1}{2}$세에 시작되며, 대부분 적어도 $3\sim3\frac{1}{2}$세에는 시작된다. 그러나, 이 시기는 다른 영구치에 비해 그 범위가 매우 넓어서 $5\sim6$세, 드물게는 그 이후에 발육이 시작되는 경우도 있다. 그러므로 하악 제2소구치의 선천결손을 조기에 진단하기에는 어려움이 있으며, 선천결손으로 진단한 경우라도 오진할 가능성이 있음을 인식하는 것이 중요하다. 저자는 두 가지 증례를 통한 임상연구와 문헌고찰을 통해 다음과 같은 결론을 얻었다. 1. 두 증례 모두에서 하악 제2소구치의 두드러진 발육지연이 관찰되었다. 2. 치배형성 이후의 석회화 속도는 거의 정상적으로 나타난 것을 보아, 발육지연은 석회화 과정보다는 분화과정에 있었던 것으로 판단되었다. 3. 이와 유사한 증례를 접하였을 경우, 치아의 선천결손으로 단정하기 보다는 발육지연의 가능성을 함께 고려 할 필요가 있을 것으로 사료되었다.

• 대한소아치과학회지
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• 제50권4호
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• pp.469-482
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• 2023

This study aimed to investigate the treatment options for the delayed eruption of mandibular premolars and identify the predictors of spontaneous eruption using panoramic radiography. The prevalence of delayed mandibular premolar eruption in this retrospective analysis, comprising 254 patients (aged 9 - 15 years), was 5.19%, with no significant difference based on gender. The mandibular second premolars were most affected (4.39%) compared to the first premolars (0.76%). No significant difference in prevalence was observed between the left and right sides. Among the treated mandibular premolars, primary molar-related lesions were identified as the leading cause (7.85%) of delayed tooth eruption. The treatment duration varied based on the Nolla stage, eruption stage, and treatment method. Teeth with Nolla stage 7 or lower had a treatment duration of 22.89 ± 11.96 months, whereas those with stage 8 or higher had a 15.02 ± 6.34 month duration. The deeper the tooth was located in the bone, the longer the treatment period became. The treatment duration varied depending on the treatment method, and statistically, there was no significant difference. The treatment durations for affected mandibular premolars increased with the depth of impaction angle of inclination. In this study, the treatment duration for delayed eruptions varied depending on the Nolla stage, eruption stage, and treatment method. Variations in the impaction depth and inclination angle across various treatment approaches, as explored in this study, might offer valuable insights into the selection of the most suitable management options for delayed tooth eruptions.