The purpose of this study was to apply cone-beam computed tomography （CBCT） to observe contour changes in human alveolar bone after tooth extraction of the maxillary central incisor and to provide original mor- phol...The purpose of this study was to apply cone-beam computed tomography （CBCT） to observe contour changes in human alveolar bone after tooth extraction of the maxillary central incisor and to provide original mor- phological evidence for aesthetic implant treatment in the maxillary anterior area. Forty patients were recruited into the study. Each patient had two CBCT scans （CBCT I and CBCT II）, one taken before and one taken three months after tooth extraction of maxillary central incisor （test tooth T）. A fixed anatomic reference point was used to orient the starting axial slice of the two scans. On three CBCT I axial slices, which represented the deep, middle, and shallow layers of the socket, labial and palatal alveolar bone widths of T were measured. The number of sagittal slices from the start point to the pulp centre of T was recorded. On three CBCT II axial slices, the pulp centres of extracted T were oriented according to the number of moved sagittal slices recorded in CBCT I. Labial and palatal alveolar bone widths at the oriented sites were measured. On the CBCT I axial slice which represented the middle layer of the socket, sagittal slices were reconstructed. Relevant distances of T on the sagittal slice were measured, as were the alveolar bone width and tooth length of the opposite central incisor. On the CBCT II axial slice, which represented the middle layer of the socket, relevant distances recorded in CBCT I were transferred on the sagittal slice. The height reduction of alveolar bone on labial and palatal sides was measured, as were the alveolar bone width and tooth length of the opposite central incisor at the oriented site. Intraobserver reliability assessed by intraclass correlation coefficients （ICCs） was high. Paired sample t-tests were performed. The alveolar bone width and tooth length of the opposite central incisor showed no statistical differences （P〈0.05）. The labial alveolar bone widths of T at the deep, middle, and shallow layers all showed statistical differences.展开更多
The size and shape of tooth crowns are morphogenetically predetermined during embryogenesis.The maxillary central incisors have contributed to sexual dimorphism,and several classifications of the form of maxillary cen...The size and shape of tooth crowns are morphogenetically predetermined during embryogenesis.The maxillary central incisors have contributed to sexual dimorphism,and several classifications of the form of maxillary central incisors are available in the literature.We,in the present study,aimed to analyze the mesiodistal(MD)measurements at two levels of maxillary central incisor,to determine its crown form.The study was conducted on 100 dental plaster models(50 males and 50 females).The MD dimensions at the contact area level MD_incisal(MD_I)and at the gingival papilla level(MD_G)and the gingivo‑incisal height of the crown were measured in the dental models using digital Vernier caliper.The data were analyzed using SPSS version 16 statistical software.The mean values of all the three parameters measured were slightly greater for males and also for the left central incisors.There were no significant differences in all the three variables when the right and left incisors were compared.Significant differences were noted when the parameters are compared between genders.The height/width ratio of crown showed a significant difference between male and female.The value of the ratio between the two MD dimensions(MD_I and MD_G)was used to determine the crown form.The ratio between the MD dimensions at incisal and gingival area showed a significant difference between genders and no such significance was found between right and left central incisors.There is a significant difference in the form of maxillary central incisors between male and female samples and not between right and left.The MD dimensions at incisal and gingival thirds decide the form of crown.展开更多
The computation of facial profile from dental morphometrics has been a subject of great interest in forensic odontology.The use of teeth to draw a profile and facial features is valuable in times of mass disasters whe...The computation of facial profile from dental morphometrics has been a subject of great interest in forensic odontology.The use of teeth to draw a profile and facial features is valuable in times of mass disasters when body remains are unavailable due to extreme destruction.This study aims to identify and evaluate applicable parameters in the permanent maxillary central incisors and the face of an individual.A correlation of these parameters establishes a mathematical equation that further charts a tooth‑facial profile table.Thirty soft and hard tissue landmarks on the face in the frontal and the lateral profiles(using standardized photographs)and seven landmarks on the facial/labial surface of the clinical crown of the permanent maxillary central incisor(using casts of the maxilla)were identified for the study.Based on these,a set of eight horizontal and seven vertical parameters on the face and four parameters on the tooth were created for the assessment.Internal and external correlations between the two were carried out and statistically analyzed.A logistic regression was made to predict the probability of the parameters most likely to be reproduced in the creation of the facial profile,based on tooth morphometrics.The results indicated a definite correlation between the facial and the tooth parameters.Among the multiple parameters,a definite correlation in the horizontal dimension could be established between the mouth width and the mesiodistal width(MDW)of the tooth.In the vertical dimension,a definite relationship existed between the crown height of the tooth and the width of the midface(zygoma‑mandible).There exist divergences in the correlation of tooth and facial parameters.展开更多
The crown form of maxillary central incisor tooth is one of the vital phenomenon for a person’s esthetics.Its crown form has been compared with other anatomical parameters such as arch form and facial form.Three diff...The crown form of maxillary central incisor tooth is one of the vital phenomenon for a person’s esthetics.Its crown form has been compared with other anatomical parameters such as arch form and facial form.Three different classes of tooth forms which relate to square,tapered,and ovoid forms are identified.The aim of this study was to morphometrically evaluate the correlation between maxillary dental arch form and the maxillary central incisor crown form.Dentate cast models of fifty male and fifty female normal occlusion controls in the age group of 18-23 years were analyzed.The mesiodistal(MD)dimensions of the maxillary central incisors were measured at incisal(MD_I)and at gingival(MD_G)levels.The transverse widths of maxillary casts were measured at the first molar and at the first premolar levels.The measured data were statistically analyzed using the SPSS software.The MD dimensions of maxillary central incisor were significantly greater in males than females.The ratio between the two MD dimensions also varied significantly among genders.The intermolar width(IMW)and interfirst premolar width(IPmW)between males and females were highly significant(P<0.05),whereas the ratio between these two parameters in males and females was not significant(P=0.43).Eighty‑eight percentage of the participants were found to have an ovoid type of maxillary arch,while only 45%of them had the ovoid form of maxillary central incisors.The MD_I and the IMW were found to be in the ratio of 1:5.5 in both genders.The MD_G and the IPmW were in the ratio of 1:4.7 in males and 1:4.5 in females.There was a weak positive correlation between MD_I and IMW(r^(2)=0.146)and between MD_G and IPmW(r^(2)=0.05).No significant concordance between the maxillary central incisor crown form and the maxillary arch form was found in this study.展开更多
文摘The purpose of this study was to apply cone-beam computed tomography （CBCT） to observe contour changes in human alveolar bone after tooth extraction of the maxillary central incisor and to provide original mor- phological evidence for aesthetic implant treatment in the maxillary anterior area. Forty patients were recruited into the study. Each patient had two CBCT scans （CBCT I and CBCT II）, one taken before and one taken three months after tooth extraction of maxillary central incisor （test tooth T）. A fixed anatomic reference point was used to orient the starting axial slice of the two scans. On three CBCT I axial slices, which represented the deep, middle, and shallow layers of the socket, labial and palatal alveolar bone widths of T were measured. The number of sagittal slices from the start point to the pulp centre of T was recorded. On three CBCT II axial slices, the pulp centres of extracted T were oriented according to the number of moved sagittal slices recorded in CBCT I. Labial and palatal alveolar bone widths at the oriented sites were measured. On the CBCT I axial slice which represented the middle layer of the socket, sagittal slices were reconstructed. Relevant distances of T on the sagittal slice were measured, as were the alveolar bone width and tooth length of the opposite central incisor. On the CBCT II axial slice, which represented the middle layer of the socket, relevant distances recorded in CBCT I were transferred on the sagittal slice. The height reduction of alveolar bone on labial and palatal sides was measured, as were the alveolar bone width and tooth length of the opposite central incisor at the oriented site. Intraobserver reliability assessed by intraclass correlation coefficients （ICCs） was high. Paired sample t-tests were performed. The alveolar bone width and tooth length of the opposite central incisor showed no statistical differences （P〈0.05）. The labial alveolar bone widths of T at the deep, middle, and shallow layers all showed statistical differences.
文摘The size and shape of tooth crowns are morphogenetically predetermined during embryogenesis.The maxillary central incisors have contributed to sexual dimorphism,and several classifications of the form of maxillary central incisors are available in the literature.We,in the present study,aimed to analyze the mesiodistal(MD)measurements at two levels of maxillary central incisor,to determine its crown form.The study was conducted on 100 dental plaster models(50 males and 50 females).The MD dimensions at the contact area level MD_incisal(MD_I)and at the gingival papilla level(MD_G)and the gingivo‑incisal height of the crown were measured in the dental models using digital Vernier caliper.The data were analyzed using SPSS version 16 statistical software.The mean values of all the three parameters measured were slightly greater for males and also for the left central incisors.There were no significant differences in all the three variables when the right and left incisors were compared.Significant differences were noted when the parameters are compared between genders.The height/width ratio of crown showed a significant difference between male and female.The value of the ratio between the two MD dimensions(MD_I and MD_G)was used to determine the crown form.The ratio between the MD dimensions at incisal and gingival area showed a significant difference between genders and no such significance was found between right and left central incisors.There is a significant difference in the form of maxillary central incisors between male and female samples and not between right and left.The MD dimensions at incisal and gingival thirds decide the form of crown.
文摘The computation of facial profile from dental morphometrics has been a subject of great interest in forensic odontology.The use of teeth to draw a profile and facial features is valuable in times of mass disasters when body remains are unavailable due to extreme destruction.This study aims to identify and evaluate applicable parameters in the permanent maxillary central incisors and the face of an individual.A correlation of these parameters establishes a mathematical equation that further charts a tooth‑facial profile table.Thirty soft and hard tissue landmarks on the face in the frontal and the lateral profiles(using standardized photographs)and seven landmarks on the facial/labial surface of the clinical crown of the permanent maxillary central incisor(using casts of the maxilla)were identified for the study.Based on these,a set of eight horizontal and seven vertical parameters on the face and four parameters on the tooth were created for the assessment.Internal and external correlations between the two were carried out and statistically analyzed.A logistic regression was made to predict the probability of the parameters most likely to be reproduced in the creation of the facial profile,based on tooth morphometrics.The results indicated a definite correlation between the facial and the tooth parameters.Among the multiple parameters,a definite correlation in the horizontal dimension could be established between the mouth width and the mesiodistal width(MDW)of the tooth.In the vertical dimension,a definite relationship existed between the crown height of the tooth and the width of the midface(zygoma‑mandible).There exist divergences in the correlation of tooth and facial parameters.
文摘The crown form of maxillary central incisor tooth is one of the vital phenomenon for a person’s esthetics.Its crown form has been compared with other anatomical parameters such as arch form and facial form.Three different classes of tooth forms which relate to square,tapered,and ovoid forms are identified.The aim of this study was to morphometrically evaluate the correlation between maxillary dental arch form and the maxillary central incisor crown form.Dentate cast models of fifty male and fifty female normal occlusion controls in the age group of 18-23 years were analyzed.The mesiodistal(MD)dimensions of the maxillary central incisors were measured at incisal(MD_I)and at gingival(MD_G)levels.The transverse widths of maxillary casts were measured at the first molar and at the first premolar levels.The measured data were statistically analyzed using the SPSS software.The MD dimensions of maxillary central incisor were significantly greater in males than females.The ratio between the two MD dimensions also varied significantly among genders.The intermolar width(IMW)and interfirst premolar width(IPmW)between males and females were highly significant(P<0.05),whereas the ratio between these two parameters in males and females was not significant(P=0.43).Eighty‑eight percentage of the participants were found to have an ovoid type of maxillary arch,while only 45%of them had the ovoid form of maxillary central incisors.The MD_I and the IMW were found to be in the ratio of 1:5.5 in both genders.The MD_G and the IPmW were in the ratio of 1:4.7 in males and 1:4.5 in females.There was a weak positive correlation between MD_I and IMW(r^(2)=0.146)and between MD_G and IPmW(r^(2)=0.05).No significant concordance between the maxillary central incisor crown form and the maxillary arch form was found in this study.
