A scoping review of hydroxyapatite-modified glass ionomer cements used for restorative dentistry

Glass ionomer cements (GICs) are considered one of the most suitable materials for restoring tooth cavities due to their unique bioactive properties. However, their inherently low mechanical strength limits their use as long-term or load-bearing restorations. Researchers have explored incorporating hydroxyapatite (HA) into GICs to enhance their strength and durability. This study aimed to review GICs modified by different forms of HA and their performance as a dental restorative material.

A structured search strategy using the terms "glass ionomer cement" and "hydroxyapatite" was applied in PubMed, MEDLINE, and Embase to identify relevant studies published in English. A data-charting form was developed by two researchers to capture the key characteristics of eligible studies for inclusion. Extracted data covered HA forms, test methods, and main findings.

The initial search identified 579 articles, and subsequently, 48 articles were included in the final review. The use of HA to modify GICs showed enhancement in mechanical, chemical, and biological properties, particularly in flexural strength and fluoride release. Compressive strength and diametral tensile strength outcomes were variable and influenced by HA proportion, size, morphology, and storage conditions.

HA modification shows promise for reinforcing GICs and improving their bioactivity. However, heterogeneous findings highlight the need for standardized methodologies and clinical trials to validate long-term outcomes.

This scoping review provides a valuable overview of HA modified-GICs research. Additionally, it identifies potential research areas that can be investigated further to enhance properties of HA modified-GICs for clinical application.