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The present study aimed to analyze mid horizontal facial third proportions, those being the interpupillary, inner intercanthal, and bizygomatic distance modified with golden proportion, The Preston proportion, golden percentage and 70% recurring esthetic dental proportion were used for determining maxillary anterior teeth width. A total of 230 participants took part in this study. The front dental and facial photographs along dental stone cast which were converted to three-dimensional (3D) models were used for evaluation. The mid horizontal facial third proportions showed no significant relationship with maxillary anterior teeth width without modification with dental proportions. Whereas, with modification, no statistically significant difference was found between inner-intercanthal distance by golden percentage and width of central incisors. The bizygomatic distance was greater than intercanine distance. While the interpupillary distance by golden proportion was found to be consistent with intercanine distance in female participants. The modified anterior teeth width was significantly different from measured values, when determined by using the three mid facial proportions with Preston and 70% recurring esthetic dental (RED) proportion. Furthermore, the measured width of maxillary anterior teeth showed no difference when plaster dental casts widths were compared with 3D models. The interpupillary, inner-intercanthal, and bizygomatic distance should not be directly used to determine maxillary anterior teeth width. While maxillary anterior teeth width can be determined by modifying the inner inter-canthal distance with golden percentage and interpupillary distance with golden proportion. Moreover, the midfacial third proportions modified with Preston and 70% recurrent esthetic dental proportion were found to be unreliable for the determination of maxillary anterior teeth widths. [ABSTRACT FROM AUTHOR]

Obtaining the size of the maxillary anterior teeth when performing an esthetic smile rehabilitation can be a difficult task. Metrics based on dental proportions to assist in the process are required. This study aimed to evaluate the lower facial third proportions i.e., the interalar, interphiltral, and intercommisural distance with dental proportions in predicting maxillary anterior teeth width in Pakistani citizens. This analytical study was conducted on 230 participants. Front face and retracted smile photographs were captured for all the participants, followed by maxillary impression making. The cast was then converted to 3D models for analysis. The data were entered into SPSS-25. Descriptive statistics were carried out for frequency, mean, standard deviation, and percentage calculation of gender, teeth widths, horizontal mid facial proportions, and age of the participants. Independent t-test was applied for analysis of gender and arch side disparity. Regression analyses were performed to analyze the relationship between independent variables (gender, age, weight, and height) and dependent variables (horizontal facial proportion, dental proportion). A p-value of ≤0.05 was considered statistically significant. The interphiltral distance (IPLD) modified with Preston proportion (PRP) showed no significant difference with combined central incisor width, whereas a significant difference was found with golden proportion (GP), 70% recurrent esthetic dental (RED) proportion, and golden percentage (GM) modification. However, the interalar (IAD) and intercommisural distance (ICoD) modified with dental proportions showed a significant difference with maxillary anterior teeth width. The width of maxillary anterior teeth determined by plaster dental cast and 3D dental cast showed no significant difference. The ICoD, IAD, and IPLD could not be used to determine combined central incisor and intercanine width directly. The interphiltral distance modified with Preston proportion is a reliable method to predict combined central incisor width in the population studied. There was a significant difference in gender disparity when ICD, IAD, and IPLD were modified with dental proportions, except in the case of IPLD by the Preston proportion group. The golden proportion, 70% RED proportion, and golden percentage by lower facial third facial proportions are not reliable methods to predict maxillary anterior teeth width. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the relationship between inner canthal distance and maxillary anterior teeth width with respect to age, gender and ethnicity. Study Design: Cross sectional study. Place and Duration of Study: Altamash Institute of Dental Medicine, Karachi, from Aug 2019 to Jan 2020. Methodology: One hundred participants from both genders with full permanent dentition, no interdental space or pathology and facial symmetry were included in this study. The measurements were carried out with digital Vernier caliper. SPSS-25 was used for statistical analysis. Results: The mean ± SD of inner canthal distance and width of maxillary anterior teeth were 2.99cm ± 0.46 and 3.82cm ± 0.35 respectively. A significant difference was found between gender (p=0.037) and inner canthal distance. The maxillary anterior teeth width and inner canthal distance varies amongst different ethnicities (p=0.01). The inner canthal distance does not vary with advancing age (p=0.87) whereas width of maxillary anterior teeth varies (p=0.04). A weak correlation value of 0.47 was found between inner canthal distance and maxillary anterior teeth width. Conclusion: This research suggests that there is a weak relationship between inner canthal distance and maxillary anterior teeth width. Therefore, a multiplication ratio of 1.27 is advised to get combined mesiodistal width of maxillary anterior teeth. Additionally, the value of both differs in various local ethnicities. Inner canthal distance does not vary with age though has significant gender disparities while maxillary anterior teeth width remains constant. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To establish whether a correlation exists between the innercanthal width and maxillary central incisors. STUDY DESIGN: A Descriptive cross sectional study. PLACE AND DURATION: Department of Prosthodontics, Dr Ishrat ul Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences Karachi and from 15th October 2012 to 25th March 2014. METHODOLOGY: One hundred and seventy five dentate individuals with intact maxillary anterior teeth were investigated. The innercanthal space was calculated among the inner canthal angles utilizing computer software. The mean dimension of the two central incisors was determined extra orally at their widest dimension. Teeth measurement and inner canthal distance association in respect to gender was evaluated by paired t test. Pearson correlation coefficients test was premeditated to establish any association amongst innercanthal space and central incisors width, significance was set at a = 0.05. RESULTS: The mean value for male and female subjects was 33.24±3.4 mm and 34.90±3.8 mm correspondingly. The mean width of maxillary central incisors for male and female subjects was recorded 15.84 ±1.4 mm and 15.92±1.3 mm. The value (P = 0.000) for both estimations were significant. The Pearson correlation coefficient were positive (r = 0.202) and highly significant (P = 0 .008) between innercanthal dimension and the maxillary central incisors. The results indicated that innercanthal ratio ratio of 1:0.462 may be used to calculate the combined width of maxillary central incisor teeth. CONCLUSION: Mean of maxillary central incisor width and inner canthal distance were higher in females significantly. The results proposed that innercanthal distance is a good prognostic factor for determining the maxillary central incisors mesiodistal width. [ABSTRACT FROM AUTHOR]

Objectives: The anisotropic natures of dental tissues result in variable properties from one point to the other within the same tooth. The aim of this study was to analyze deciduous incisors enamel and dentin for elastic modulus and hardness. In addition, retained deciduous incisors were assessed to compare properties with exfoliated teeth.Methods: Deciduous mandibular incisors either exfoliated at physiological age or retained were included in this study. Samples were prepared by dissecting teeth in transverse sections and surfaces under investigation were prepared and polished for nanoindentation. Nanoindentation was performed at multiple sites using Hysitron [TI 725 Ubi] testing instrument. Data analysis was performed using SPSS software (version 20) to calculate absolute hardness and elastic modulus. The statistical significance was calculated using the t-test.Results: The hardness of human deciduous incisor varies between 0.01-7 GPa. The highest value of hardness was observed for the incisal edge (5.09 ± 0.64 GPa) followed by mid-surface enamel and cervical enamel. The hardness of mantle dentin was (0.56 ± 0.19 GPa) and the inner dentin was (0.34 ± 0.12 GPa).Conclusions: The average hardness of primary teeth enamel is lower than permanent teeth enamel. The hardness of retained teeth enamel is greater than exfoliated teeth however lower than permanent teeth enamel of the equivalent region. [ABSTRACT FROM AUTHOR]