Four-Year Pulp Survival in a Randomized Trial on Direct Pulp Capping

Published:October 26, 2023DOI:https://doi.org/10.1016/j.joen.2023.10.008

ABSTRACT

Introduction

This study aimed to assess pulp survival in a randomized trial on pulp lavage in adult non-painful posterior teeth with carious pulp exposure. The treatment included complete caries excavation, direct pulp capping with MTA, and immediate restoration with composite resin.

Methods

Fluid was collected from the pulp wound to assess MMP-9 and total protein (TP) values. Prior to pulp capping, cavities were randomly (block randomization, n = 48) washed with a physiological saline or a sodium hypochlorite solution (2.5% NaOCl). Treatment outcome was assessed clinically (cold test) and radiographically after at least 1 and again after at least 3 years. Painful failures were differentiated from non-painful failures. Pulp survival was estimated using the Kaplan-Meier method including 95% confidence intervals (CI) up to 1500 days.

Results

From the 96 patients originally enrolled, 73 individuals could be followed continuously. The clinical observations indicated a beneficial and sustained effect of pulp lavage with 2.5% NaOCl over a control treatment with physiological saline solution on estimated pulp survival 1500 days post-intervention, with 7% (95% CI: 1% - 40%) in the saline group versus 55% (95% CI: 30% - 100%) in the NaOCl group. High MMP-9/TP values in pulpal fluid collected from the exposed site indicated early and painful treatment failures, yet were not associated with failures that occurred more than 250 days after intervention.

Conclusions

The low 4-year success rates reported here challenge the concept of direct pulp capping in the cases that were included. NaOCl lavage did not only increase the survival of affected pulps substantially, but particularly diminished painful failures (33% in the NaOCl group versus 62% in the saline group). The lack of predictive value of MMP-9 assessments beyond early treatment failures points to inflammatory states of the pulp tissue under deep caries, which are not related to neutrophil infiltration.