Conventional caries removal and sealed caries in permanent teeth: a microbiological evaluation

The aim of this study was to compare microbiological infection after conventional carious dentine removal with incomplete carious dentine removal and sealing.

Eighty-seven patients (12-50 years of age) under treatment at the Dental Clinics of the Federal University of Rio Grande do Sul (UFRGS), Brazil, participated in the study. The patients presented 90 posterior permanent teeth with primary caries. The lesions were coronal, active, and reached at least the middle third of the dentine. None of the teeth exhibited spontaneous pain, sensitivity to percussion or apical pathology (detected through radiographic exams). Pulp sensibility was confirmed by the cold test. The lesions were divided into 2 experimental groups: complete caries removal (CCR) based on hardness criteria (n=60 lesions) and incomplete caries removal (ICR) and sealing (n=32 lesions). Microbiological samples were obtained from the initial demineralized dentine, after CCR and after ICR-Seal.

The number of anaerobic and aerobic bacteria, lactobacilli, and mutans streptococci decreased at the end of treatment (p<0.05). Significantly less anaerobic bacteria (p<0.01), aerobic bacteria (p=0.02), and mutans streptococci (p<0.01) growth was observed after ICR-Seal compared to CCR. The difference in lactobacilli was insignificant (p=0.08). The amount of bacteria detected after conventional caries removal was higher than that which remained in sealed caries lesions.

The results suggest it is not necessary to remove all carious dentine before the restoration is placed because over time, sealing of carious dentine results in lower levels of infection than traditional dentine caries removal.

The results of this study indicate that sealed carious dentine was less infected than the remaining dentine left after conventional caries removal and sealing. Our results support treatment of deep carious lesions in one session with incomplete removal of carious dentine.