# In Vitro Evaluation of the Effect of NaOCl Deproteinization of MIH-Affected Hard Dental Tissue on the Marginal Integrity of a Glass Hybrid Material

## TL;DR

This study investigates whether using NaOCl to remove proteins from MIH-affected teeth improves the fit of a dental restoration material.

## Contribution

The study provides new in vitro evidence on the effect of NaOCl deproteinization on the marginal integrity of a glass hybrid material in MIH-affected teeth.

## Key findings

- Deproteinization with NaOCl reduced marginal crevice size under stereoscopic microscopy but not under SEM.
- The median marginal crevice was significantly smaller in deproteinized specimens under stereoscopic analysis.

## Abstract

The enamel of teeth affected by Molar–Incisor Hypomineralization (MIH) has been reported to have a higher protein content. Though a glass hybrid is recommended for restoring teeth with MIH in children, there is a lack of in vitro research on the influence of deproteinization on its marginal integrity. Therefore, this study aimed to evaluate whether enamel pretreatment with 5.25% NaOCl reduces the size of the marginal crevice of such restorations. Out of eight extracted teeth with severe MIH, restored using a glass hybrid (Equia Forte HT/GC), half underwent deproteinization. A stereoscopic and a scanning electron microscope (SEM) were used for sections analysis. The median value of the marginal crevice measured using stereoscopic microscopy (n = 17) was significantly lower for the deproteinized (6.78 μm) than for the standard-prepared specimens (12.61 μm), p = 0.008. On SEM images, the median marginal crevice (n = 10) was 69.40 μm versus 156.77 μm for the deproteinized and standard groups, respectively. The differences, however, were not statistically significant. This study only partially confirmed the hypothesis that pretreatment with NaOCl reduces marginal crevices between the Equia Forte HT material and hypomineralized hard tissues. Further studies on the effect of deproteinization on the marginal adaptation of glass hybrid materials are needed.