Title:  Standards for mesiodistal and buccolingual crown size and height of primary molars in a sample of Spanish children

Abstract:  Aim The aim of this study was to obtain mesiodistal, buccolingual and height sizes of dental crowns of first and second primary molars in a sample of Spanish children given, not only their anthropological and forensic significance, but also their clinical interest for the future analysis of restorative and orthodontic treatments. Materials and methods Measurements of mesiodistal, buccolingual size and height of the crowns of primary molars were studied. A transversally descriptive design was carried out and the interrelationship between these three dimensions was established. A sample of 703 first and second primary molars was selected from healthy Spanish boys and girls from 4 to 9 years old. Molars presenting anomalies of the crowns, caries or restorations were excluded. Measurements were made on dental plaster models, using a vernier caliper. Descriptive statistics and Pearson correlation coefficient was obtained and Wilcoxon’s non-parametric test was applied for comparison of the mean, analysis of sexual dimorphism and comparison of antimeric teeth. Results Average sizes of each group of molars were obtained. Sexual dimorphism was studied utilizing the Wilcoxon test. A variability of relationship between the measurements was found in each molar studied. Primary second molars had less variability than first molars in the three measurements obtained. The measurement with the least variability was height, followed by mesiodistal size. Conclusions Measurements of primary molars showed that average sizes of boys’ molars were significantly larger than those of girls. Relationship between the three measurements studied was variable but second molars showed less variability than first molars. The relationship between height and width was found significant in most of the molars.