Histopathological Condition of the Remaining Tissues after Endodontic Infection of Rat Immature Teeth

doi:10.1016/j.joen.2013.09.015

Journal of Endodontics

Volume 40, Issue 4, April 2014, Pages 538-542

https://doi.org/10.1016/j.joen.2013.09.015 Get rights and content

Abstract

Introduction

Recently, case reports have shown that immature teeth diagnosed with necrotic pulp and periapical periodontitis can be repaired through a regenerative endodontic procedure. True regeneration depends on the presence of stem cells in the remaining vital tissues. The aim of this study was to evaluate the histologic condition of the pulp tissue, root apical papilla, and periapical tissues after inducing endodontic infection in immature rat teeth for different periods.

Methods

This study evaluated 18 first upper rat molars (36 roots). Periapical lesions were induced and were confirmed radiographically, and the animals were divided into 3 groups according to the days of pulp exposure for endodontic infection induction: 30, 60, and 90 days. Histologic analysis was performed in 5 different areas (ie, cervical, middle, and apical root canal thirds; the apical papilla; and the periapex surrounding the apical papilla).

Results

At 30 days, one third of the specimens still showed vital but intensely inflamed pulp tissue in the apical third and vital apical papilla with varying degrees of inflammation. After 60 days, the results were similar with respect to the apical pulp tissue and apical papilla. Completely necrotic pulp tissue in the space canal and vital apical papilla were observed in about 67% of the cases after 90 days.

Conclusions

Vital pulp tissue was observed in the apical third until 60 days and in the vital apical papilla until 90 days of infection in a rat model.

Section snippets

Animals

The experimental protocol was approved by the Araçatuba School of Dentistry local animal ethics committee, and the animals were maintained according to the Guide for the Care and Use of Laboratory Animals from the National Institutes of Health (Bethesda, MD). In this study, we used a total of 18 upper first molars (36 roots) of 18 male Wistar rats weighing 160–180 g and aged 5 weeks at the beginning of the experiments. The animals were housed under standard controlled conditions and were

Radiographic Findings

Periapical radiographic examination reveled periapical lesions in all observed period of time (Fig. 1A–C).

Control

The pulp tissue was completely intact, and a cell-rich zone was observed between the pulp and apical papilla (Fig. 1E). The apical papilla appeared to contain less blood vessels and cellular components compared with the dental pulp and the apical cell-rich zone.

30 Days

On day 30, no remaining tissue was found in all analyzed cervical thirds (12/12) or in the majority of the middle thirds (11/12). Interestingly, 1 root showed moderately inflamed pulp tissue in the middle third, which was totally

Discussion

Recently, several clinical case reports have shown that immature permanent teeth are capable of undergoing apexogenesis despite the presence of a periapical lesion resulting from root canal infection 1, 2, 3, 4. A sequence of clinical procedures is essential from the disinfection to the filling of the space with blood (10).

In the present study, the pulp in the apical third was preserved in one third of the cases until 60 days, and the apical papilla was preserved until 90 days, showing that the

Acknowledgments

The authors deny any conflicts of interest related to this study.

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Citation Excerpt :
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SCAP cells expressed FGFR1 and FGFR2. Exposure of SCAP to bFGF enhanced cell proliferation, and the expression cyclinB1, cdc 2, and TIMP-1, but not type I collagen. U0126 pretreatment and co-incubation attenuated the bFGF-induced proliferation, cdc2, cyclin B1 and TIMP-1 proteins’ expression, but not type I collagen in SCAP.
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Basic ResearchHistopathological Condition of the Remaining Tissues after Endodontic Infection of Rat Immature Teeth

Abstract

Introduction

Methods

Results

Conclusions

Section snippets

Animals

Radiographic Findings

Control

30 Days

Discussion

Acknowledgments

J Endod

J Endod

J Endod

J Endod

J Dent

J Endod

J Endod

J Endod

J Endod

J Endod

J Endod

J Endod

J Endod

Basic Research
Histopathological Condition of the Remaining Tissues after Endodontic Infection of Rat Immature Teeth