Evaluation of Pulp Repair after BiodentineTM Full Pulpotomy in a Rat Molar Model of Pulpitis.

Sandra Minic,Catherine Chaussain,Tchilalo Boukpessi,Anne Valot-Salengro,Jérémy Sadoine,Marion Florimond,Emmanuelle Renard

doi:10.3390/biomedicines9070784

Abstract

Dental pulp is a dynamic tissue able to heal after injury under moderate inflammatory conditions. Our study aimed to evaluate pulp repair under inflammatory conditions in rats. For this purpose, we developed a rat model of controlled pulpitis followed by pulpotomy with a tricalcium silicate-based cement. Fifty-four cavities were prepared on the occlusal face of the maxillary upper first molar of 27 eight-week-old male rats. E. coli lipopolysaccharides at 10 mg/mL or phosphate-buffered saline PBS was injected after pulp injury. Non-inflamed molars were used as controls. Levels of inflammation-related molecules were measured 6 and 24 h after induction by enzyme-linked immunosorbent assay of coronal pulp samples. Pulp capping and coronal obturation after pulpotomy were performed with tricalcium silicate-based cement. Four and fifteen days after pulpotomy, histological and immunohistochemical analysis was performed to assess pulp inflammation and repair processes. Our results showed significantly higher levels of innate inflammatory proteins (IL-1β, IL-6, TNF-α and CXCL-1) compared with those in controls. Moderate residual inflammation near the capping material was demonstrated by histology and immunohistochemistry, with the presence of few CD68-positive cells. We showed that, in this model of controlled pulpitis, pulpotomy with BiodentineTM allowed the synthesis at the injury site of a mineralized bridge formed from mineralized tissue secreted by cells displaying odontoblastic characteristics. Analysis of these data suggests overall that, with the limitations inherent to findings in animal models, pulpotomy with a silicate-based cement is a good treatment for controlling inflammation and enhancing repair in cases of controlled pulpitis.

Highlights

Dental pulp (DP) is a highly dynamic connective tissue encapsulated in mineralized dental tissues, which is responsible for tooth vitality, sensitivity, immune response and repair and regeneration
The inflammation induced by phosphate-buffered saline (PBS) or LPS was evaluated by comparing the pulp concentrations of a range of biological markers at the time of pulpotomy to those in healthy pulp
Labelling extended over a wider area for 24-h (Figure 6h,i) than for 6-h (Figure 6f,g) induction with PBS/LPS, and cells were located near the mineralized barrier at the canal opening and along the root wall. This in vivo study shows for the first time that a calcium silicate-based cement induces dentin repair when applied as pulp capping material after pulpotomy in a controlled pulpitis model in rat molars

Summary

Introduction

Dental pulp (DP) is a highly dynamic connective tissue encapsulated in mineralized dental tissues, which is responsible for tooth vitality, sensitivity, immune response and repair and regeneration. Biomedicines 2021, 9, 784 significant role in the defense against pathogens during tissue injury [1,2,3]. In response to pathogen-associated molecular patterns (PAMPs), such as lipopolysaccharides (LPS), DP cells upregulate innate immunity effectors, leading to the recruitment and activation of immune cells [5]. These inflammatory events mediate the interplay between infection, host defense, tissue injury and repair [6]. The cellular responses are much more challenging and require the recruitment of stem/progenitor cells to the injured site and their subsequent proliferation and differentiation into a new generation of odontoblast-like cells [7]

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