# Comparison of Two Types of Composite-Opaquer Combinations Masking Ability for Tooth Discoloration without Clinically Visible Opacity

## TL;DR

This study compares how well different combinations of opaquer and composite materials can hide tooth discoloration, finding that some combinations work better than others.

## Contribution

The study introduces a novel comparison of two opaquer-composite combinations for masking tooth discoloration with varying thicknesses.

## Key findings

- Combinations using Creative Color A2 opaquer and Vitalescence composite showed significantly better masking ability.
- Thicker samples (1mm) performed better than thinner ones (0.5mm) in masking tooth discoloration.
- Vitalescence composite and Creative Color A2 opaquer achieved more desirable ΔE values compared to other combinations.

## Abstract

A few studies have examined the masking ability of the combined application of opaquer and resin composites on tooth discoloration.

This study investigated the combined application of opaquer-composite to mask discolored backgrounds by utilizing two opaquers and resin composites.

In this in vitro research, we used two composite resins, Vitalescence (Ultradent) and Gradia Direct (GC), and two opaquers: Pink opaque (Cosmedent) and Creative Color A2 (Cosmedent).
Seventy-two specimens were made as disks in 8 groups (n=9), with 1.0mm and 0.5mm thicknesses. One surface of each disk was coated by one of the opaquers and cured. The 4mm-thick
composite disks from both composite brands were also made as a reference, representing the inherent color of the material. Then, the composite disks from the opaquer-coated surface were placed
on a C4 porcelain disk as a background to simulate a discolored tooth. Color measurement for all specimens was performed using a spectrophotometer device. The color difference of
each test group and 4 mm thick disks of the same composite were measured using the formula CIELAB (ΔE * ab). Statistical analysis was performed by using ANOVA and Tukey's Post hoc tests.

Statistically significant differences were observed between the eight groups (p= 0.001). The thickness, composites, and opaquer variants significantly affected the ΔE*. The samples with 1mm thickness,
the Vitalescence composite, and the Creative Color opaquer A2, had significantly lower ΔE* than the 0.5mm samples, the Gradia composite, and the Pink opaquer, respectively.
The number of samples with desirable ΔE was significantly higher in the Vitalescence composite group than in the Gradia composite, and the Creative Color A2 opaquer had significantly more desirable ΔE than the Pink opaquer.

Most results that achieved acceptable masking ability were obtained with combinations of Creative Color opaquer A2+ Vitalescence / Gradia composite in 0.5 or 1mm thicknesses.