This study was performed to find the relationship between pressure and adhesive force during probing in pits or fissures, clinical diagnosis, histopathological diagnosis, and tooth breakdown. The pits and fissures of 39 extracted premolar and molar teeth were probed with the pressure of about 800g and were clinically diagnosed. At the same time, the pressure of inserting the explorer into the pit or fissure and the adhesive force of pulling the explorer were measured by the previously reported system. Then a vertical ground section through the pit or fissure was prepared from each tooth. The section was observed by light and polarizing microscopy and by microradiography.
The coincidence between the clinical and histopathological diagnoses was not good in initial caries but good in advanced caries. There was some tooth breakdown caused by the explorer in all the cases diagnosed as clinically carious and in more than one third of the cases diagnosed as clinically sound. There was histopathological caries in all the cases accompanied by tooth breakdown and in many cases not accompanied by this. The mean adhesive force at probing was greater with the advance of clinical caries and the adhesive force of 100g was between the mean adhesive forces of the groups of clinically sound teeth, and C1. There was histopathological caries in all of the 13 cases observed with an adhesive force of over 100g, and in the 8 cases in which the caries advanced into the dentin. There was tooth breakdown in all cases observed with an adhesive force over 100g.
These results suggest that it is necessary to investigate the appropriate pressure for probing because the pressure of 800g during probing in this study may produce a traumatic tooth breakdown favoring lesion progression.