Analysis of esthetic factors and evaluation of esthetic perception for maxillary anteriors of dental students / 대한치과보철학회지

PURPOSE: This research is to investigate factors that affect dental aesthetics and analyze whether individual perception affects and difference of genders affects the esthetic factors. MATERIALS AND METHODS: Seventy dental students of Chonnam University aged from 25 to 35 years old without periodontal problems were included. Maxillary dental cast for participants were made, and standardized photo was taken with a digital camera. Maximum visual width and the position of gingival zenith of maxillary anterior teeth and maximum height of the maxillary central incisors were measured by a measurement program and the shape of central incisor was categorized. Questionnaire was conducted to evaluate esthetic perception. SPSS program was used to perform statistical analysis. RESULTS: The average visual width ratio of right maxillary anteriors was 1.38:1:0.78 and 1.41:1:0.81 for the left which differ from the golden ratio. The width to height ratio for right and left central incisor was 0.84 and 0.83 respectively. The gingival zenith position was determined to be: mostly, central incisors and canines were located in the distal side, lateral incisors were located in the center. The visual width ratio of right maxillary anterior teeth, ratio of width to height of central incisor, gingival zenith position, crown morphology and amounts of gingival exposure upon smiling were not significantly different between genders, and facial patterns and these dental esthetic factors were not related to aesthetic perception. CONCLUSION: Even though participants had the visual width ratio of maxillary anteriors or ideal width to ideal height of central incisors that did not agree with the golden ratio, they had high satisfaction for dental esthetics. Esthetic perception depends more on subjective judgements of participants than objective indices.

Relación entre distancia intercantal y ancho de dientes anterosuperiores en jóvenes chilenos / Relationship between intercanthal distance and width of maxillary anterior teeth in young chilean population

RESUMEN: Objetivo: La distancia intercantal (DIC) es utilizado para la selección de los dientes anterosuperiores y es la dimensión más estable en el tiempo Sin embargo, es variable entre razas y poblaciones, particularmente en Sudamérica. El objetivo de este estudio es establecer la correlación entre DIC y el ancho de los dientes maxilares anteriores en una población adulta jóven del sur de Chile. Materiales y métodos: Estudio de corte transversal. Participaron 111 estudiantes voluntarios (promedio edad 22.4 años; 65.7% hombres) de la ciudad de Valdivia, sur de Chile. Se midió DIC y el ancho mesiodistal del incisivo central superior, la distancia lineal de los cuatro incisivos superiores y de los seis dientes anterosuperiores en modelos de estudio. Se analizó la diferencia de las mediciones según sexo (test de Student; p<0.05) y la correlación lineal entre DIC y las medidas dentales (r=0.8; p<0.05. STATA v.10.0) Resultados: Todas las mediciones fueron significativamente mayores en hombres que en mujeres (p<0.05). Se observó una correlación estadísticamente significativa entre la DIC y la distancia lineal de los cuatro incisivos superiores (p=0.04) y de los seis dientes anterosuperiores (p=0.03). Se obtuvo una razón de 1:0.94 y 1:1.28 de DIC con la distancia lineal de los cuatro incisivos superiores y los seis dientes anterosuperiores, respectivamente. Conclusión: La DIC presentó una correlación lineal y proporcional con los dientes anteriores, pudiendo estimar el ancho lineal de los dientes anterosuperiores en una población adulta joven del Sur de Chile.

ABSTRACT: Objective: Intercanthal distance (ICD) is a parameter used to select the upper anterior teeth and the most stable measurement overtime. However, it is variable between race and populations, particularly in South America. The aim of this study was to establish the correlation between ICD and the width of maxillary anterior teeth in young adult population from southern of Chile. Materials and Methods: A Cross-sectional study was designed. One Hundred eleven volunteers students (average age 22.4 years; 65.7% men) from Valdivia city (southern of Chile) were included. ICD and mesiodistal width of maxillary central incisor, linear distance of the four upper incisors and linear distance of the six upper front teeth in plaster study models weremeasured. The mean of difference measurement between sex (ttest; p<0.05) and the linear correlation between DIC and the width of the upper anterior were analyzed (r=0.8; p<0.05; STATA v.10.0). Results: All measurement were significantly higher in male than female (p<0.05). A statistically significant correlation between ICD and distance of the four upper incisors (p=0.04) and the six upper front teeth (p=0.03) were observed. A 1:0.94 and 1:1.28 ratios between ICD with the linear distance of the upper incisors and the six maxillary anterior were obtained respectively. Conclusion: ICD presented a linear and proportional correlation with maxillary anterior teeth. With these results it is possible to estimate the linear width of the upper front teeth in young adult population from southern of Chile.

Shade selection of primary maxillary anterior teeth in children using Vitapan classical shade guide.

Aim: The purpose of this study was to determine the closest matching shade for primary maxillary anterior teeth from the most widely used Vitapan classical shade guide available for permanent teeth. Materials and Methods: A total of 313 children aged between 3 and 5 years were evaluated. Vitapan classical shade guide was used to determine the shade of six primary maxillary anterior teeth. Scores obtained were noted down in a scoring sheet and values were tabulated. Data collected were tabulated and statistically analyzed using Pearson Chi‑square test. Results: A1 was found to be the closest matching shade for primary maxillary anterior teeth. D3 was found to be the least prevalent shade for primary maxillary anterior teeth. There was no statistical significant difference in the shades among teeth of same quadrant (p > 0.05) and also between teeth of right and left quadrants (p > 0.05), respectively. Conclusion: A1 shade of Vitapan classical shade guide is the most prevalent shade for primary maxillary anterior teeth and can be satisfactorily reproduced to all primary maxillary anterior teeth in general.

Position of maxillary central incisor and intercanine width in Korean adults / 대한치과보철학회지

PURPOSE: The aim of this study was to propose the position of maxillary anterior teeth and intercanine width measurements based on the incisive papilla in accordance with the cephalic type and gender of dentate Korean adult with normal teeth alignment. MATERIALS AND METHODS: 42 students with Class I normal occlusion, without crowding or spacing, were selected from the Chonnam National University School of Dentistry. The lateral skull radiographs of the subjects were taken and were classified as different cephalic types, based on their PFH / AFH ratios. 42 casts of their maxilla were prepared and both the distance between the upper central incisors and the middle of the incisor papilla was measured with a vernier caliper (A) and the distance between the maxillary canine cusp tips (B) were measured. Statistical analysis was performed using SPSS version 15 and their significance was investigated. RESULTS: For dolichocephalic group, the mean values for A and B were 8.43 (SD: 0.61) and 36.73 (SD: 2.17), respectively. The mean value for A was 8.51 (SD: 1.27) for the mesocephalic group and 8.76 (SD 1.03) for the brachycephalic group. The mean value for B was 35.91 (SD: 1.86) for the mesocephalic group and 37.34 (SD: 2.23) for the brachycephalic group. For the male group, the mean A value was 8.86 (SD: 1.04) and the mean B value was 37.60 (SD: 0.24). For the female group, the mean A value was 8.41 (SD: 0.93) and the mean B value was 36.18 (SD: 2.01). The difference between male and female group in A values were not statistically significant (P>.05). The B values of the male subjects were greater than those of the female subjects and was statistically significant (P<.05). CONCLUSION: 42 students with normal dentition and occlusion in korea, the distance from the incisive papilla and the incisal edge of maxillary central incisors had no difference in cephalic type or gender. However, the distance between the cusp tip of both canines had significant difference in gender where the male showed higher values than the female, while having no difference in cephalic types.

Anthropometric analysis of maxillary anterior buccal bone of Korean adults using cone-beam CT

PURPOSE: The aim of this study was to evaluate the thickness of buccal and palatal alveolar bone and buccal bony curvature below root apex in maxillary anterior teeth of Korean adults using Cone-beam CT images. MATERIAL AND METHODS: The 3D image was reconstructed with dicom file obtained through CBCT from 20 - 39 year old Korean subjects (n = 20). The thickness of buccal and palatal plate, root diameter, the buccal bony curvature angle below root apex and the distance from root apex to the deepest point of buccal bony curvature were measured on maxillary anterior teeth area using OnDemand3D program. RESULTS: Mean thickness of buccal plate 3 mm below CEJ was 0.68 +/- 0.29 mm at central incisor, 0.76 +/- 0.59 mm at lateral incisor, and 1.07 +/- 0.80 mm at canine. Mean thickness of palatal plate 3 mm below CEJ was 1.53 +/- 0.55 mm of central incisor, 1.18 +/- 0.66 mm of lateral incisor, 1.42 +/- 0.77 mm of canine. Bucco-lingual diameter 3 mm below CEJ was 5.13 +/- 0.37 mm of central incisor, 4.58 +/- 0.46 mm of lateral incisor, and 5.93 +/- 0.47 mm of canine. Buccal bony curvature angle below root apex was 134.7 +/- 17.5degrees at central incisor, 151.0 +/- 13.9degrees at lateral incisor, 153.0 +/- 9.5degrees at canine. Distance between root apex and the deepest point of buccal bony curvature of central incisor was 3.67 +/- 1.28 mm at central incisor, 3.90 +/- 1.51 mm at lateral incisor, and 5.13 +/- 1.70 mm at canine. CONCLUSION: Within the limitation of this study in Korean adults, the thickness of maxillary anterior buccal plate was very thin within 1mm and the thickness of palatal plate was thick, relatively. The buccal bony curvature below root apex of maxillary central incisor was higher than that of lateral incisor and canine and it seems that the buccal bony plate below root apex of central incisor is most curved.

A Retrospective clinical study of survival rate of single implant in maxillary anterior teeth / 대한치주과학회지

This study was performed to investigate the survival rate of single implant used in maxillary anterior region during follow up periods. 231 patients whose single missing tooth in maxillary region had been replaced with 237 implant at the periodontal dept. of Yonsei University Hospital between February 1993 and December 2004. The following results are compiled from 231 patients who received single implant surgery. 1. The major cause of single tooth loss in maxillary anterior region is trauma, followed by periodontal disease and congenital missing. 2. The total survival rate of single implant placed in maxillary anterior region is 94.5%. 3. The survival rate of single implant placed in type II and type IV was 100% and in type lll was 92.7%. As for the bone quantity, the survival rate in type A(100%) was most, followed by type B(97.3%) and type C, D (93.5%). 4. The survival rate of implant placement combined with advanced surgery was 94.4%. The results showed that the placement of single implant is considered as a reliable treatment option for a single missing tooth in maxillary anterior region except in certain extreme conditions especially with poor bone quality and quantity.

Radiographic evaluation of alveolar bone profile of maxillary anterior teeth in Korean young adult / 대한치주과학회지

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, guttapercha 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 CW/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+/-0.7mm between two central incisor, and 2.8+/-0.6mm between central and lateral incisor. 2. Mean CW/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+/-0.2mm and 3.5+/-0.2mm between two central incisor, 3.0+/-0.2mm and 2.8+/-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.

Study of Normative Gingival Proportion in Anterior Maxilla / 대한치주과학회지

Tooth is the most important element in esthetic consideration on facial area. Tooth alignment which is in harmony with gingiva, lips, and face is also key element. The purpose of this study was to give a clinical discipline for restoration of gingival contour, which contains a ratio of maxillary 6 anterior teeth, research for gingival contour etc., in case of rehabilitation of maxillary anterior teeth. 300 Dankook university dental school students ,who is their twenties and free from periodontitis, participate in this study. The result was from each 70 males and females who had normal occlusion and tooth alignment. Length, width and length/width ratio of maxillary 6 anterior teeth were 0.74-0.81 in male, 0.81-0.84 in female. There was significant difference between male and female. The most deepest position of gingiva in maxillary central incisor and canine was located in distal part of teeth and maxillary lateral incisor was middle portion. In maxillary central incisors, gingival line of the most deepest point appeared significant difference between male and female (p<0.01) whereas there was no difference in lateral incisors and canines. Distance between interdental papilla apex and the most deepest portion appeared significant difference beween male and female. Distance of the deepest positon of gingiva is statistically significant except maxillary central incisors and lateral incisors. Standard deviation and mean of the width of labio-lingual were measured in cervical area and there was a significant difference both male and female.(p<0.01) From this result, we could get the mean of maxillary anterior gingival line and these results have great value in clinical guidance in studying maxillary anterior teeth.

Morphology of the Maxillary Anterior Teeth in Akha, Lahu Tribes in Northern Thailand / 체질인류학회지

In order to clarify the genetic relationship between Koreans and Akha, Lahu native tribes around the mountain area in Northern Thailand, authors examined the metric and non-metric mophological variations of the maxillary anterior teeth. The subjects were 54 in Akha tribe (25 males, 29 female) and 114 in Lahu tribe (57 males, 57 females), and their ages were 20 to 65 (mean age 34). The prevalence of the shovel-shaped incisor in maxillary anterior teeth was 85% in Lahu tribe. Among the another non-metric variations, the prevalence of the peg lateralis was 3 cases in Akha female and 8 cases in Lahu tribe (4 males, 4 females). And the supernumernary tooth located between the right and left maxillary central incisors was observed in 2 cases, the congenital missings of the maxillary lateral incisor were in 2 cases(1 Akha, 1 Lahu tribe), and the congenital missings of the maxillary canine were in 3 cases(1 Akha, 2 Lahu tribe). The maximal mesio-distal diameters of the maxillary anterior teeth in Akha and Lahu tribes showed no discrepancy with regard to those of koreans and the dental measurements of the male were larger than the female (p<0.05). The dental measurements of the Lahu tribe were more closer to Korean than those of Akha Tribe were. Especlally, the mean mesio-distal diameter of the maxillary anterior teeth in Lahu female had no difference to Korean adult female (p<0.05). On the basis of the above results, authors thought that the anthropological similarity to Koreans was higher in Lahu than Akha tribe with respect to the dentition, but the further anthropological studies such as the height, body proportion, and finger print should be needed.

Experimental study of the vertical location of the centers of resistance for maxillary anterior teeth during retraction using the laser reflection technique / 대한치과교정학회지

The delivery of optimal orthodontic treatment is greatly influenced by a clinician's ability to predict and control tooth movement achieved by applying known force systems to the dentition. It is important to determine the location of the center of resistance of a tooth or group of teeth to better understand the nature of their displacement characteristics under the various force levels. The purpose of this study was to define the location of the centers of resistance of various units of the upper anterior segment for lingually directed 100gm and 200gm force in a dry human skull. The units investigated were composed of four incisors and six anterior teeth. In addition, the effect of change in force magnitude on the location of the center of resistance of these units was investigated. The laser reflection technique was used to measure the initial displacements of the consolidated teeth under loading. The results were as follows: 1. The instantaneous center of resistance for the four anterior teeth was located vertically between level 4 and level 5-that is, at 37.4 % apical to the cementoenamel junction level. 2. The instantaneous center of resistance for the six anterior teeth was located vertically just beneath level 5-that is, at 50.3 % apical to the cementoenamel junction level. 3. Increasing force levels had little effect on the location of the center of resistance of a given unit. 4. The location of the instantaneous center of resistance shifted apically as the number of dental units consolidated increased.