Enamel thickness of human mandibular canine: A radiographic study

Enamel thickness of posterior mandibular dentition has been widely studied to explore the role of masticatory load in determining enamel pattern. Mesial-distal pattern of enamel thickness in posterior teeth is either a reflection of increasing magnitude of bite forces posteriorly or a developmental phenomenon. In the earlier sexual dimorphism studies, the thickness of enamel was more in females than males. However, research diverted to the importance of dentin in determining sexual dimorphism and its relation to the bite forces, with males showing greater dentin resulting in bigger teeth in them. This study had two objectives, one to examine the mesiodistal pattern of enamel thickness of mandibular canines and second to examine the sexual dimorphism in enamel proportion of mandibular canines. Crown width, mesial and distal enamel thickness, enamel cap area and tooth area were measured on digital periapical radiographs of mandibular canines of 85 subjects (44 females and 41 males) of Asian ethnicity using ImageJ. Mesial-distal enamel thickness was statistically analyzed by mixed factorial ANOVA and sexual dimorphism was assessed by logistic regression analysis. Enamel was significantly thicker on the distal than the mesial margins of human mandibular canines similar to the posterior dentition pattern. Sexual dimorphism was observed in enamel cap area as well mesial and distal enamel thickness with females showing more relative proportion of enamel than males

A multi-program analysis of cleft lip with cleft palate prevalence and mortality using data from 22 International Clearinghouse for Birth Defects Surveillance and Research programs, 1974-2014

Background Cleft lip with cleft palate (CLP) is a congenital condition that affects both the oral cavity and the lips. This study estimated the prevalence and mortality of CLP using surveillance data collected from birth defect registries around the world. Methods Data from 22 population- and hospital-based surveillance programs affiliated with the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR) in 18 countries on live births (LB), stillbirths (SB), and elective terminations of pregnancy for fetal anomaly (ETOPFA) for CLP from 1974 to 2014 were analyzed. Prevalence and survival (survival for LB only) estimates were calculated for total and subclassifications of CLP and by pregnancy outcome. Results The pooled prevalence of total CLP cases was 6.4 CLP per 10,000 births. The prevalence of CLP and all of the pregnancy outcomes varied across programs. Higher ETOPFA rates were recorded in most European programs compared to programs in other continents. In programs reporting low ETOPFA rates or where there was no ascertainment of ETOPFA, the rate of CLP among LB and SB was higher compared to those where ETOPFA rates were ascertained. Overall survival for total CLP was 91%. For isolated CLP, the survival was 97.7%. CLP associated with multiple congenital anomalies had an overall survival of 77.1%, and for CLP associated with genetic/chromosomal syndromes, overall survival was 40.9%. Conclusions Total CLP prevalence reported in this study is lower than estimates from prior studies, with variation by pregnancy outcomes between programs. Survival was lower when CLP was associated with other congenital anomalies or syndromes compared to isolated CLP