Risk assessment of food retention related to occlusal morphology

Morphological characteristics of occlusal surface of primary molars can cause food retention, increasing the risk of caries development. Objectives: The aim of this study was to evaluate morphological characteristics of first primary teeth related to food retention. Methods: Therefore, 54 teeth of 27 children (24 to 30 months) were enrolled at this research. They took a chocolate cookie and the food retention area was documented by digital photography in two experimental times (t₀:0 and t₁:30 minutes). The food retention was analyzed by observation of the local retention in digital photographs at the final time using the Image Tool Program 3.0 (UTHSCSA, 2002). After that, prophylaxis was done in order to remove food wastes and a silicone condensation impression to obtain the replica's stones that were analyzed by stereoscopic microscopy (20X). The morphological characteristics were identified and drawn according to anatomical complexity (1 to 5), being considered presence or absence of fissures in pits and grooves as well as considering if these fissures were isolated or conjugated. Results: The mandibular molars have shown more food retention (66.67%) when compared to maxillary ones (44.44%) at the final time (Qui Square's test, p= 0.002). It was observed a positive correlation between morphology and food retention for maxillary (Spearman's Correlation, rs= 0.63, p=0.0004) and mandibular teeth (Spearman's Correlation, rs= 0.56, p=0.002). The more complex anatomy (values 4 and 5) increases approximately 13 times the risk for food retention for maxillary and mandibular molars, according to Odds ratio test (p=0.01 and p=0.04, respectively). Conclusion: Considering these results, we can conclude that there is a significant correlation between morphological complexity of first primary molars and food retention in occlusal surface. Moreover, we can suggest that the presence of fissures in grooves and pits even isolated increases the risk of food retention in occlusal surface of first primary molars.