# Morphological changes of the apical foramen after enlargement: A scoping review of in vitro studies

## TL;DR

This review examines how enlarging the apical foramen affects root morphology using in vitro studies.

## Contribution

The study provides a synthesis of evidence on morphological changes caused by instrumentation beyond the apical foramen.

## Key findings

- Instrumentation beyond the apical foramen causes morphological changes like dentinal microcracks.
- Standardized methodologies are needed for accurate detection of these changes.
- Findings could improve clinical practices in root canal preparation.

## Abstract

To outline the current evidence on root morphological changes after enlarging the apical foramen with NiTi instruments.

A search was performed in the Virtual Health Library, PubMed, EMBASE, Scopus, Web of Science, Science Direct and SciELO databases, in addition to a manual search in Google Scholar, between January 2017 and October 2023. Articles published in English that describe in vitro studies investigating root morphological changes after instrumentation 1 mm beyond the major apical foramen were included. The quality of evidence in the included studies was also analyzed.

The search retrieved 367 articles. Of these, four studies were eligible for data synthesis and analysis, all of them in vitro studies. Synthesis of the results of these in vitro studies showed a larger number of root morphological changes such as experimental dentinal microcraks in samples submitted to instrumentation beyond the apical foramen when compared to micro-CT images obtained before preparation.

The in vitro studies analyzed in this scoping review indicate that instrumentation beyond the major foramen of the root canal, promotes morphological changes in this area and that the adoption of standardized methodologies would not only increase the accurate detection and characterization of these changes but also facilitate the application of these findings in clinical trials and patient care.

Key words:Endodontics, apical morphology, root canal preparation.