Wet and dry deep cavity preparations compared by a novel odontoblast culture technique

The human odontoblast's unique cellular extension within dentin does not easily allow culturing by traditional methods. This study leaves these cells in their natural position in the dentin. Deep preparations were made through the occlusal surfaces of extracted human third molars. The crowns were separated from the roots and the pulps gently teased from the chambers, leaving the odontoblast layer intact. These inverted pulp chambers were then incubated in cell culture medium for 2 to 4 days. Trypan blue staining was used to detect non-vital odontoblasts, and the differentiation between vital and nonvital cells was verified by SEM and toluidine vital staining. Control teeth and areas not adjacent to the preparation showed no blue staining, indicating intact cells. Areas of nonvital cells were greatest with wider preparation. Irrigation decreased odontoblast death with wide preparations. No difference due to irrigation was detected in narrow preps. A comparison of wet preparations to which heat was applied versus dry preparations showed statistically similar results. This study provides a simple in vitro method for the study of odontoblasts with their processes intact within dentin.