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Purpose: To assess the different forms of maxillary central incisors (MCI) and determine their association with the shape of the face for men and women. Materials and Methods: A total of 200 subjects (100 women, 100 men) aged between 18 and 30 years with healthy dentition were randomly selected from K.L.E. V.K Institute of Dental Sciences, Belagavi, India. Two standardized photographs (portrait and shape of the MCI) were taken for each subject and opened in AutoCAD 2009 software that was used to prepare technical drawings of face and tooth forms. The dental ratios (extent of line TA: extent of line TB) obtained after the tracings, were classified as tapered (≤0.61), ovoid (>0.61 and <0.69), or square (≥0.70). This classification was used to relate tooth form to the shape of the face and compare the form of MCI between men and women. Association between the shape of the MCI and the face was determined by Chi‐square test using R 3.3.1 software. Results: The most prevalent tooth form among the subjects was ovoid (women, 32%; men, 31%) followed by tapered (women, 13%; men, 16%). The least prevalent shape was square (women, 5%; men, 3%). The most prevalent face shape was tapered (women, 34%; men, 25%) followed by ovoid (women, 15%; men, 22%) and the least prevalent was square (women, 1%; men, 3%). An association between face shape and tooth form was statistically not significant. Conclusion: The most prevalent tooth form in both men and women was ovoid, and the least prevalent was square. The association between face shape and tooth form was not significant and did not abide by William's "Law of Harmony." However, there was an association between face shape and gender. [ABSTRACT FROM AUTHOR]

Objectives: Several studies have focused on the timing of fluoride intake relative to the development of dental fluorosis. This study reports the relationships of fluoride intake during the first 48 months of life with fluorosis on early-erupting permanent teeth. Methods: Subjects were followed from birth to 48 months with questionnaires every 3-4 months. Questionnaires gathered data on intakes from water, diet, supplements, and dentifrice to estimate total fluoride intake. Early-erupting permanent teeth of 579 subjects were assessed for fluorosis using the Fluorosis Risk Index (FRI) at approximately age 9. Fluorosis cases were defined as having FRI definitive or severe fluorosis on both maxillary central incisors. Individuals with FRI questionable fluorosis were excluded. The importance of fluoride intake during different time periods was assessed using t-tests and logistic regression. Results: One hundred and thirty-nine (24%) subjects had fluorosis on both maxillary central incisors. Mean fluoride intake per unit body weight (bw) ranged from 0.040 to 0.057 mg/kg bw, with higher intake during earlier time periods and relative stability after 16 months. In bivariate analyses, fluoride intakes during each of the first 4 years were individually significantly related to fluorosis on maxillary central incisors, with the first year most important (P < 0.01), followed by the second (P < 0.01), third (P < 0.01), and fourth year (P = 0.03). Multivariable logistic regression analyses showed that, after controlling only for the first year, the later years individually were still statistically significant. When all four time periods were in the model, the first (P < 0.01) and second years (P = 0.04) were still significant, but the third (P = 0.32) and fourth (P = 0.82) were not. Conclusions: The first two years of life were most important to fluorosis development in permanent maxillary central incisors; however, this study also suggests the importance of other individual years. [ABSTRACT FROM AUTHOR]

The shape of a patient's face is commonly used as a reference to select the shape of the maxillary central incisors in edentulous patients. The validity of this relationship has not been proved. The objective of this clinical study was to determine whether a relationship exists between maxillary central incisors and face shapes. Casts were made of the maxillas of 50 men and 50 women. A standardized digital photographic procedure was used to record frontal views of each subject's face and of the maxillary central incisors of the dental casts. The shapes of the maxillary central incisors were compared with the face forms. Shape matches were evaluated according to their Hausdorff distance (HDD). The function h(A,B) is called the directed HDD from shape A to shape B (this function is not a true distance). It reflects the distance of the point of shape A that is farthest from any point of shape B and vice versa. The similarity of both shapes is given as a non-negative number. The value 0.0 indicates that the figures are identical (after scaling and shifting). Higher values indicate that shapes differ more substantially. Significant differences on the 5% level were calculated using the nonparametric Mann­Whitney U and Kruskal­Wallis tests. The face shape from the chin margin to the eyebrow line (superior edges of the eyebrows) produced a better match than the one from the chin to the hairline (P < 0.0001). On average, the maxillary central incisors displayed a variability (0.084 ± 0.028) that was higher by a factor of 1.9 than the face shapes (chin margin to the eyebrow line, 0.045 ± 0.015). In the interindividual comparison, the shapes of the maxillary central incisors of women displayed a significantly smaller HDD than the ones of the men (P < 0.0001). [ABSTRACT FROM AUTHOR]