• Journal of Periodontal and Implant Science
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• 제36권2호
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• pp.461-471
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• 2006

In order to achieve a satisfactory esthetic result of periodontal surgery or implant in maxillary anterior area, periodontists must be aware of normal alveolar bone anatomy. The purpose of this study was to evaluate the relationship of alveolar bone morphology to tooth shape and form. 78(mean age : 25 yrs) periodontally healthy volunteers participated in this study. Two maxillary central incisor and one lateral incisor were selected to study. With minimal local anesthesia, gutta-percha cone inserted to labial gingival sulcus of selected teeth just after bone sounding with periodontal probe. Metal ball (4mm diameter) attached to palatal fossa of central incisor. Then, periapical radiograph was taken according to long cone paralleling technique. After film scan, labial alveolar bone profile reproduced along interproximal bone and apical ends of gutta-percha cones on computer screen. By utilizing computer program, the distance from height of interproximal bone to the labial bone crest in central incisor-central incisor and central incisor-lateral incisor area was measured and converted to real distance by using vertical length of metal ball on film. After measuring crown length & width of central incisor, the 10 individuals ranked lowest GW/L ratio (crown width/length ratio) and the 10 ranked highest were selected as having a long-narrow(group N), or a short-wide(group W) form of the central incisors. Means of the distance from height of interproximal bone to the labial bone crest of group N, W were calculated and compared by means of independent t-test. The results were as follows: 1. Mean distance from the height of the interproximal bone to the labial bone crest was $3.5{\pm}0.7mm$ between two central incisor, and $2.8{\pm}0.6mm$ between central and lateral incisor. 2. Mean GW/L ratio of group N was 0.57, and group W was 0.8. Mean distance from the height of the interproximal bone to the labial bone crest of group N was higher than group W in both measured area(measurements of group N, W were $3.9{\pm0.2mm$ and $3.5{\pm}0.2mm$ between two central incisor, $3.0{\pm}0.2mm$ and $2.8{\pm}0.2mm$ between central and lateral incisor), but there were no statistically significant differences when the groups were compared. Within the limits of the present study, there was a tendency that subjects with long-narrow teeth have more scalloped alveolar bone profile than subjects with short-wide teeth in upper anterior area, but no statistically significant differences were found.

• The Journal of Advanced Prosthodontics
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• 제9권4호
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• pp.315-320
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• 2017

PURPOSE. The aim of this investigation was to analyze the dimensions of clinical crowns and to classify the crown and the gingival type in the anterior teeth in Korean young adults. MATERIALS AND METHODS. Casts were obtained from 50 subjects ranging in age from 24 to 32. Measurements of length and width were made on the casts using a pair of digital calipers on the entire dentition. Crown thickness and papilla height were also measured and MDW/CL (mesiodistal width to clinical length) and CW/CL (cervical width to clinical length) ratios of the maxillary anterior teeth were calculated. The K-clustering method was used for CW/CL to classify the anterior tooth shape into three groups (tapered, ovoid, and square), and one-way analysis of variance and Duncan's post-hoc comparison were used to evaluate statistical significance between the groups. Pearson's correlation analysis was performed between tooth shape and papillary height (PH) to demonstrate the correlation between tooth shape and gingival morphological characteristics. RESULTS. The average length of the maxillary central incisors was 9.89 mm; the mesio-distal width was 8.54 mm; and the ratio of width/length was 0.86 in Korean young adults. The average bucco-palatal thickness of the central incisor was 3.14 mm at the incisal 1/3 aspect. Ovoid type was the most common tooth shape (48%), followed by square type (29%) and taper type (23%) in the central incisors of Korean young adults. Tooth shape and gingival type were correlated with each other. CONCLUSION. New reference data were established for tooth size in Korean young adults and the data show several patterns of tooth shape and gingival type. Clinicians should diagnose and treat based on these characteristics for better results in the Korean population.

• 대한치과교정학회지
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• 제31권5호
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• pp.505-515
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• 2001

대한치과교정학회 부정교합백서 발간위원회에서 보관중인 한국성인 정상교합자의 표본(남 22명, 여 55명)과 연세대학교 치과대학 교정과에서 부정 교합 백서 발간을 위하여 수집한 표본(남자: 21명)을 이용한 한국성인 정상교합자의 치아크기의 계측과 비율에 관한 연구를 통해, 한국성인 정상교합자의 치아크기의 평균치를 구하고, 조화로운 교합관계와 심미성의 획득에 기여하는 치아크기의 비율을 구하여 다음과 같은 결론을 얻었다. 1. 한국성인 정상교합자의 남녀 치아크기의 평균치를 구하였다. 2. 남녀간 치아크기의 평균치 비교에서 상하악 제1대구치를 제외한 치아에서 통계적으로 유의하게 남자의 치아크기가 여자의 치아크기에 비하여 크게 계측되었다(p<0.05). 3. 계측된 한국성인 정상교합자의 치아크기 평균치를 바탕으로 교정치료시 전치부에서의 적절한 수직피개도와 수평피개도, 구치부에서의 적절한 교합관계를 예측할 수 있게 해주는 치아비율을 산출하였다. 1) Sum of incisors = 4 : 2.97 2) Neff anterior coefficient = 1.28 3) Bolton의 anterior ratio = 78.29%, overall ratio = 91.14% 4. 혼합치열기에서 맹출된 4전치 폭경의 합과 상하악 편측 미맹출 견치와 소구치 폭경의 합과의 상관관계를 조사한 결과 양의 상관관계를 나타내었으며, 이 상관관계에 의해 상하악 편측 미맹출 소구치 폭경의 합을 예측할 수 있는 회귀방정식을 구하였다. 1) 미맹출 편측 상악 견치와 소구치 폭경의 합 예측 회귀방정식 = 10.435018 + 0.513346 ${\times}$ (하악 4전치의 합) 2) 미맹출 편측 하악 견치와 소구치 폭경의 합 예측 회귀방정식 = 9.654002 + 0.502565 ${\times}$ (하악 4전치의 합)

• Journal of Periodontal and Implant Science
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• 제35권2호
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• pp.359-369
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• 2005

It has been suggested that morphologic characteristics of the periodontium are partly related to the shape and form of the teeth. Furthermore, the severity of symptoms of periodontal disease have been proposed to differ among these various morphologic entities or "biotypes". The purpose of the present study was to examine the relationship between the form of the crowns in the maxillary anterior tooth segment and (1) a group of morphological characteristics and (2) the thickness of the gingiva. The thickness of gingiva was measured by ultrasonic device(SDM). 100 subjects devoid of symptoms of destructive periodontal disease were examined regarding, e.g., probing depth, gingival recession, width of keratinized gingiva, thickness of the keratinized gingiva. From maxillary study cast, the width(at the apical third-CW) and the length(CL) of the crowns of the 6 anterior teeth were determined. A CW/CL-ratio was calculated for each tooth and averaged for each tooth region. The individual mean CW/CL-ratio values for the central incisors were ranked. The 10 subjects ranked highest and the 10 ranked lowest were selected as having either a long-narrow(group N) or a short-wide(group W) form of the crown of the tooth. The data for each of the examined parameters were averaged for each tooth region in each subject and mean values for subjects in groups W and N were compared using the Student t-test. Stepwise multiple regression analysis, including data from the whole sample, was performed for each tooth region with the thickness of the free gingiva as the dependent variable. The results from the analyses demonstrated that individuals with a long-narrow form of the central incisors displayed, compared to individuals with a short-wide crown, form (l) a narrow zone of keratinized gingiva, (2) a pronounced "scalloped" contour of the gingival margin. There was no significant difference between groups N and W with respect to the thickness of the keratinized gingiva. The CW/CL-ratio data revealed that a certain form of the crowns in the central incisors was accompanied by a similar form in the lateral incisors and canine tooth region. The regression analyses demonstrated that the thickness of the keratinized gingiva in central, lateral incisors and canines was significantly related to the width of the keratinized gingiva.

• Journal of Periodontal and Implant Science
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• 제53권5호
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• pp.362-375
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• 2023

Purpose: The aim of this study was to investigate the relationships between gingival thickness (GT) and keratinized gingiva width (KGW), papilla height (PH), and crown ratio (CR) by employing transgingival probing and an intraoral scanner (IOS). Methods: This cross-sectional study examined 360 maxillary anterior teeth from 60 patients. GT was assessed using transgingival probing with an endodontic spreader. KGW, CR, and PH were measured using an IOS. One-way analysis of variance, the Student's t-test, and Spearman correlation coefficients were employed for statistical analysis. Results: Higher GT was significantly associated with thinner KGW in the central region (P=0.019). There was no statistically significant difference in GT between teeth (P=0.06). PH was lower in lateral teeth than in canines (P=0.047), with a PH of 2.99 mm in lateral teeth. The KGW was narrower in canines than in central teeth (P=0.007). A moderate correlation was observed between KGW and PH in the central region (P=0.01), while a weak negative correlation was found between KGW and CR (P=0.043). Conclusions: A moderate negative correlation was found between GT and KGW, as well as between PH and KGW in central teeth. In contrast, a weak negative correlation existed between CR and KGW. The PH (2.99 mm) was lower in lateral teeth than in canines. The traditional paradigm, which suggests a positive correlation between KGW and GT, was reevaluated by measuring KGW using an IOS.

• 대한치과보철학회지
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• 제57권2호
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• pp.118-126
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• 2019

목적: 상악 전치부에 대한 심미적 요소들에 대하여 조사하고 남녀 간 차이 및 개인 심미적 인식도와의 연관성이 있는 지에 대해 분석하고자 한다. 대상 및 방법: 치주적으로 건강한 25 - 35세의 전남대학교 치의학전문대학원생 70명을 대상으로 상악 모형을 제작하였고 디지털 카메라를 이용하여 표준화된 사진을 촬영하고 계측 프로그램을 이용하여 상악 전치의 근 원심 최대 시각적 폭경과 치은 정점의 수직적 위치, 중절치의 최대 높이를 계측하였고 중절치의 치관 형태를 분류하였다. 참가자들의 심미 인식도 평가를 위해 설문조사를 시행하였다. 통계분석은 SPSS program을 이용하여 시행하였다. 결과: 상악 전치 시각적 폭경 비율의 경우 우측은 1.38:1:0.78, 좌측은 1.41:1:0.81의 평균값을 가졌고 황금 비율과는 차이가 있었다. 중절치관의 폭경 대 장경 비율의 경우 우측은 0.84, 좌측은 0.83의 평균값을 가졌다. 치은 정점의 위치의 경우 중절치는 원심측, 측절치는 중심, 견치는 원심측에 주로 위치하였다. 상악 전치부 시각적 폭경 비율, 중절치 폭경 대 장경 비율, 치은 정점 위치, 치관 형태, 미소시 치은 노출 정도는 남녀 간 차이가 없었고 이런 요소들과 안모의 형태와 참가자들의 심미적 인식도와는 관련성이 없었다. 결론: 참가자들은 상악 전치 시각적 폭경의 황금비율 및 중절치 치관의 이상적 폭경 대 장경 비율과는 일치하지 않았지만 상악 전치부 심미성에 대한 만족도가 높았다. 심미적 인식은 참가자들의 수치화된 객관적 지표보다는 주관적 판단이 더 중요함을 알 수 있었다.

• Journal of Korean Dental Science
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• 제7권2호
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• pp.66-79
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• 2014

Purpose: To analyze the amount and pattern of tooth movement and the changes in arch dimension of mandibular dentition after orthodontic treatment using a new three-dimensional (3D)-indirect superimposition method. Materials and Methods: The samples consisted of fifteen adult patients with class I bialveolar protrusion and minimal anterior crowding, treated by extraction of four first premolars with conventional sliding mechanics. After superimposition of 3D-virtual maxillary models before and after treatment using best-fit method, 3D-virtual mandibular model at each stage was placed into a common coordinate of superimposition using 3D-bite information, which resulted in 3D-indirect superimposition for mandibular dentition. The changes in mandibular dental and arch dimensional variables were measured with Rapidform 2006 (INUS Technology). Paired t-test was used for statistical analysis. Result: The anterior teeth moved backward, displaced laterally, and inclined lingually. The posterior teeth showed statistically significant contraction toward midsagittal plane. The amounts of backward movement of anterior teeth and forward movement of posterior teeth showed a ratio of 6 : 1. Although the inter-canine width increased slightly (0.8 mm, P<0.05), the inter-second premolar, inter-first molar, and inter-second molar widths decreased significantly with similar amounts (2.2 mm, P<0.05; 2.3 mm, P<0.01; 2.3 mm, P<0.001). The molar depth decreased (6.7 mm, P<0.001) but canine depth did not change. Conclusion: A new 3D-indirect superimposition of the mandibular dentitions using best-fit method and 3D-bite information can present a guideline for virtual treatment planning in terms of tooth position and arch dimension.

• 대한치과교정학회지
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• 제35권6호
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• pp.420-432
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• 2005

Bolton 분석이 치아크기 부조화를 예측하기 위해 널리 사용되고 있지만 그 정확도에 대해서는 의문이 제기되어왔다. 이에 본 연구는 부정교합자를 대상으로 하여 실제 전치부 부조화가 나타나는 양상을 조사하고. 그것에 영향을 주는 요인에 대해서 평가하고자 하였다.. 연구대상은 다양한 부정교합(Class I. Class II, Class III. Class III surgery)을 가졌으며, 교정치료를 마친 80명의 환자들로 구성되었다. 치료 전 모형, 치료 후 모형으로부터 얻어진 셋업 모형 그리고 치료 전후 측모 두부 X-선 계측사진을 분석하였으며 다음과 같은 결과를 얻었다. 한국인 부정교합자의 전치부 Bolton ratio는 Bolton의 표본 및 한국인 정상교합자 표본과 비교해 보았을 때 평균, 표준편차범위가 다소 크게 나타났다. 실제 전치부 부조화는 상악의 부족(deficiency)을 보이는 경우가 상악의 과잉(excess)을 보이는 경우보다 많았다. 전치부 Bolton ratio로부터 예측한 전치부 부조화는 셋업 모형을 통해서 얻은 실제 전치부 부조화와 비교해 버았을 때 차이를 보였다 (p<0.05). 성별 및 부정교합군은 실제 전치부 부조화에 유의한 차이를 보이지 않았다 (p>005). 수직피개와 상악 치아 절단연 두께는 실제 전치부 부조화와 상관관계가 거의 없는 것으로 나타났다. 다중회귀분석 결과 실제 전치부 부조화에는 치료 전 모형의 전치부 Bolton ratio, 치료 후 상악 전치가 교합평면과 이루는 각, 치료 후 절치간각, 치료 전 상악 우측 측절치 폭경 등의 요인이 기여하는 것으로 나타났다.

• Imaging Science in Dentistry
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• 제48권3호
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• pp.191-199
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• 2018

Purpose: This study classified alveolar arch forms and evaluated differences in alveolar bone thickness among arch forms in the anterior esthetic region using cone-beam computed tomography (CBCT) images. Materials and Methods: Axial views of 113 CBCT images were assessed at the level of 3 mm below the cementoenamel junction (CEJ) of the right and left canines. The root center points of teeth in the anterior esthetic region were used as reference points. Arch forms were classified according to their transverse dimensions and the intercanine width-to-depth ratio. The buccolingual alveolar bone thickness of each tooth was measured at 3 mm below the CEJ and at the mid-root level. Differences in the mean thicknesses among arch forms were analyzed. Results: Anterior maxillary arches could be classified as long narrow, short medium, long medium, and long wide arches. Significant differences in buccolingual alveolar bone thickness among the arch groups were found at both levels. The long wide arches presented the greatest bone thickness, followed by the long medium arches, while the long narrow and short medium arches were the thinnest. Conclusion: Arch forms were classified as long narrow, short medium, long medium, and long wide. The buccolingual alveolar bone thickness exhibited significant differences among the arch forms.

• 대한치과보철학회지
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• 제56권1호
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• pp.40-49
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• 2018

상, 하악 전치부 치아의 비심미적인 비율을 갖게 되는 원인은 매우 다양하다고 보고된다. 특히 하악 치조골의 정출을 동반한 전치부 치아의 마모 시, 치은연 상승에 의한 치은 노출 양 증가 및 부적절한 치아 비율로 인해 심각한 기능적, 심미적 문제를 일으킬 수 있다. 이런 경우, 임상적, 방사선학적 방법을 이용한 수직고경 평가와 함께 미소선, 연조직 및 경조직의 형태뿐 아니라 치아의 해부학적 형태와 비율 또한 고려하여야 하는데, 수직고경의 증가 또는 임상적 치관 연장술 및 보철적 수복을 통해 치아간의 근/원심, 폭/길이 비율을 개선시켜야 하며, 이 때 전방 유도를 함께 고려해야 심미적, 기능적으로 만족스러운 치료결과 및 예후를 얻을 수 있다. 본 증례는 48세 남성 환자로서 만성치주염으로 인한 상악 좌, 우측 중절치 및 하악 좌측 중절치의 결손, 하악 전치부 치아의 마모 및 치조골의 정출 등으로 인하여 비심미적인 상, 하악 전치부 비율을 갖고 있었으며, 체계적인 진단 및 치료계획을 통해 기능적, 심미적으로 만족할 만한 결과를 얻었기에 이를 보고하고자 한다.