Pulpal status of human primary molars with coexisting caries and physiological root resorption

Aim: This study sought to investigate the effect of caries, in association with physiological root resorption, on the pulpal status of human primary molars. Design: Fifty-three mandibular primary molars were obtained from children requiring extractions under general anaesthesia. Following extraction, teeth were split longitudinally and placed in Zamboni's fixative. Teeth were categorised according to i) the depth of caries (less than or greater than halfway through dentine thickness) and ii) the degree of physiological root resorption (<33%, 34-66% or >67% of the root length). Ten-micrometre pulp sections were subject to indirect immunofluorescence using a combination of PGP 9.5 (a general neuronal marker), CD45 (a general neuronal marker), and Ulex europaeus agglutinin I (a marker of vascular endothelium). Image analysis was used to determine the percentage area of staining (PAS) for innervation and immune cells. Results: Marked differences were seen between different samples, but there were no significant differences in mean PAS for PGP 9.5 or CD45 according to the degree of caries or extent of physiological root resorption (two-way anova, P > 0.05). Conclusion: Findings suggest that even if primary molars are undergoing exfoliation, they show comparable caries-induced changes to teeth without physiological root resorption, thus retaining potential for healing and repair.