Relationship between depth of approximal caries lesions and presence of bacteria in the dentine in primary and permanent posterior teeth: a radiographic examination with microbiological evaluation

Abstract

Objectives: We aimed to determine the relation between the radiographical depth of approximal lesions and the presence of bacteria in the dentine in posterior teeth in both dentitions.

Material and methods: Sample 1 consisted of 34 approximal lesions in primary molars in children aged 5-7 years old. Sample 2 consisted of 48 approximal lesions in molars and premolars in adult patients aged 18-67 years old. All lesions were in need of restorative treatment according to the dentists. During the operative interventions dentine biopsies were collected with a sterile bur just pulpally of the enamel-dentin junction. Two authors evaluated the presence/absence of bacterial colonies. The lesions depth on bitewing radiographs (R_SCORING) were assessed independently by two examiners twice using the ICCMS classification system: R_I=initial-; R_M=moderate-; R_E=extensive caries.

Results: In sample 1, the R_SCORING was distributed as follows: R_I=15; R_M=12; RE = 7. In 9 cases the lesions were clinically cavitated. Bacteria were visible on the agar plates in one case (7%) of the R_I lesion, 86% of the R_M lesions and in all the R_E lesions, (p < .001). In sample 2, R_SCORING was distributed as follows R_I=14; R_M=23; R_E=9. In 15 cases, the lesions were clinically cavitated. In 2 cases (14%), there were visible bacteria on the agar plates among the R_I lesions, while this was the case in 86% of R_M lesions and in 100% of R_E lesions (p < .001).

Conclusions: R_M and R_E lesions seem to harbor bacteria in the dentine and are candidates for invasive treatment. In contrast, R_I lesions should in general be managed non-invasively.

Keywords: Approximal caries; bacteria; bitewing; caries treatment; clinical assessment.