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

The human odontoblast's unique cellular extension within dentin does not ea sily allow culturing by traditional methods. This study leaves these cells in their natural position in the dentin. Deep preparations were made throug h the occlusal surfaces of extracted human third molars. The crowns were se parated from the roots and the pulps gently teased from the chambers, leavi ng the odontoblast layer intact. These inverted pulp chambers were then inc ubated in cell culture medium for 2 to 4 days. Trypan blue staining was use d to detect nonvital odontoblasts, and the differentiation between vital an d nonvital cells was verified by SEM and toluidine vital staining. Control teeth and areas not adjacent to the preparation showed no blue staining, in dicating intact cells, Areas of nonvital cells were greatest with wider pre paration. 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.