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

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?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?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.