Innervation of human tooth pulp in relation to caries and dentition type

The neural status of carious teeth, particularly those associated with a pa inful pulpitis, is largely unknown. This study sought to determine differen ces in the innervation density of human primary and permanent teeth and whe ther caries or painful pulpitis was associated with anatomical changes in p ulpal innervation. Coronal pulps were removed from 120 primary and permanen t molars with a known pain history. Teeth were categorized as intact, moder ately carious, or grossly carious. Using indirect immunofluorescence, we la beled sections for the general neuronal marker, protein gene product 9.5. U sing image analysis, we found permanent teeth to be significantly more dens ely innervated than primary teeth. While there was no significant correlati on with reported pain experience, neural density in both dentitions increas ed significantly with caries. Analysis of these data suggests that caries-i nduced changes in neural density may be functionally more important in the regulation of pulpal inflammation and healing than in the processing and pe rception of dental pain.