Symptomatic Irreversible Pulpitis Induces Increased Levels of Human NLRP3 in Gingival Crevicular Fluid Compared to Saliva: A Case Control Observational Study.

Introduction: The goal of this case-control observational study was to compare the levels of the human nucleotide-binding domain, leucine-rich repeat, and pyrin domain-containing-3 (NLRP3) protein in the saliva and gingival crevicular fluid (GCF) of patients with symptomatic irreversible pulpitis (SIP) and healthy controls.

Methods: The 16 patients in the control group were matched with the 16 patients in the SIP group to create a total of 32 patients. In addition to saliva, GCF (n = 48) samples were collected from the involved tooth (n = 16), contralateral tooth (n = 16), and adjacent tooth (n = 16) in the SIP group. Saliva and GCF were taken from the healthy group as a baseline. An independent t-test was used for statistical analysis. The random-intercept model was used to compare the average NLRP3 levels in the SIP tooth, adjacent tooth, and contralateral tooth taking age as a covariate, and the P value was adjusted using Bonferroni correction.

Results: There were significantly higher levels of NLRP3 in the saliva of SIP patients (1.78 ± 1.14 ng/ml) compared to the healthy control (0.70 ± 0.70 ng/ml) and in the GCF of the involved tooth (5.72 ± 0.63 ng/ml) compared to healthy people (1.60 ± 0.42 ng/ml) (P < .001). In SIP patients the mean difference of NLRP3 levels between SIP and contralateral teeth was significant at 4.13 ng/ml (95% confidence interval, 3.52-4.70 P < .001) and a mean difference between adjacent teeth and contralateral teeth was significant at 3.53 ng/ml [95% confidence interval, 2.94-4.12 P < .001]. The NLRP3 in GCF and saliva had a negative association in the affected tooth but a negligible correlation in healthy controls.

Conclusion: The NLRP3 inflammasome has the potential to be employed as a molecular diagnostic biomarker for pulpal disorders.