Determination of endotoxins in caries: association with pulpal pain

The aims of this study were: (i) to determine the presence or absence of endotoxins in the superficial and deep layers of carious lesions of symptomatic and asymptomatic teeth with vital pulps; (ii) to quantify the amount of endotoxin present; and (iii) to associate the presence of endotoxins with the acute pulpal pain derived from the irreversible pulpitis.

Two specimens of carious dentine were taken under aseptic conditions from symptomatic teeth with irreversible pulpitis (n = 9) and asymptomatic teeth with reversible pulpitis (n = 11). The first specimen was taken from a layer of superficial caries and the second from a deeper one. Sound dentine was also collected from intact teeth without restoration and used as a noncarious control group (n = 4). During the patient sampling procedure an effort was made to collect an equal quantity of caries and sound dentine in all cases (approximately 6 mg). The extraction of endotoxins was performed using the Phenol-water method. The assay and quantitative determination of endotoxins was performed by the Quantitative Chromogenic test using Limulus Lysate. Data were analysed statistically using either independent or paired t-tests.

The results indicated that endotoxins were present in the superficial and deep layers of caries of all symptomatic teeth with irreversible pulpitis (0.15078 and 0.12111 ng mL-1, respectively), with significantly greater amount (P < 0.01) in the superficial compared to the deep layer. Endotoxins were found in superficial and deep layer of caries of all asymptomatic teeth with reversible pulpitis (0.12091 and 0.07163 ng mL-1, respectively), with significantly greater amounts (P < 0.001) in the superficial compared to the deep layer. The results also demonstrated that significantly greater concentrations (P < 0.005) of endotoxins were present in the superficial carious layer of symptomatic compared with asymptomatic teeth (0.15078 and 0.12091 ng mL-1, respectively). Likewise, significantly greater amounts (P < 0.001) of endotoxins were present in the deep carious layer of symptomatic compared with asymptomatic teeth (0.12111 and 0.07163 ng mL-1, respectively). In sound dentine no endotoxins were detected.

This study demonstrates that endotoxins are present in carious lesions of symptomatic and asymptomatic teeth. The amount of endotoxin was significantly greater in the superficial compared to the deep layer of carious dentine. More endotoxins are present in caries of painful teeth compared with those without symptoms.