How Do the Etching Mode and Thermomechanical Loading Influence the Marginal Integrity of Universal Adhesives?

Abstract

SUMMARY Objective: This study evaluated the effect of etching mode and thermomechanical loading on universal adhesives. Methods and Materials: Two universal adhesives, Peak Universal and Adhese Universal, were used in two etching modes as the experimental groups: Peak Universal etch-and-rinse (PER), Peak Universal self-etch (PSE), Adhese Universal etch-and-rinse (AER), and Adhese Universal self-etch (ASE). Two adhesives considered gold standards were used as control groups: OptiBond FL (OER) was used as a control group for the etch-and-rinse (ER) mode, and Clearfil SE Bond (CSE) was used as a control group for the self-etch (SE) mode. Standardized class V cavities were created on the buccal and lingual surface in 30 extracted caries-free human third molars. Each adhesive and resin composite was applied according to the manufacturer's instructions. The specimens were subjected to thermomechanical loading (TML) immediately after the fillings were placed. Before and after TML, replicas and photographs of the fillings were performed and evaluated quantitatively and qualitatively. The Mann-Whitney U-test or Kruskal-Wallis test was used for quantitative analyses, and Fisher exact test was used for qualitative analysis. Results: Adhese Universal achieved a significantly higher percentage of continuous margin in the enamel than Peak Universal for the two types of etching both before and after TML (except for the SE group after TML). In dentin, the greatest percentage of continuous margin was achieved for Adhese Universal in the ER group (100%) before TML and for both universal adhesives in the SE groups (61%) after TML. For both etching modes and both time points, Adhese Universal had a greater percentage of continuous margin than Peak Universal for the whole margin. For the ER approach, significant differences were observed both before and after TML, and for the SE approach, significant differences were observed before TML. TML did not cause a significant decrease in the percentage of continuous margin in the enamel, but the results were the opposite in dentin. A qualitative assessment using World Dental Federation criteria did not show statistically significant differences between the groups. Conclusions: Scanning electron microscope assessment of marginal integrity showed that the evaluated factors such as etching mode and TML significantly influenced the marginal integrity of the universal adhesives. The replica method shows that laboratory and clinical assessment methods complement each other and give a broader view of marginal integrity.

Internal Adaptation of Composite Fillings Made Using Universal Adhesives—A Micro-Computed Tomography Analysis

“…Moreover, mechanical loading causes tooth and filling deformations, which lead to increases in existing gaps or the development of new gaps at the tooth-filling interface [16,17,33]. Unfortunately, there is a lack of standardized TML protocols; however, the parameters used in this study were successfully implemented in previous studies [7,22,33]. Water storage is an easier and cheaper method but more time-consuming than thermocycling or mechanical loading; however, the combination of those three aging methods can reproduce the conditions in the oral cavity [34].…”

“…Destructive methods use a tracer or dye and damage the sample by cutting it into sections to visualize the extent of staining along the tooth-filling interface using methods such as light microscopy, scanning electron microscopy (SEM), or optical microscopy [20,21]. Exemplary non-destructive methods are the replica technique in combination with SEM for external marginal adaptation [7,22] or X-ray micro-computed tomography (µCT) analysis [21,23]. This three-dimensional (3D) method enables the detection of all internal gaps and irregularities as well as their changes over time.…”

Clinical effects of different etching modes for universal adhesives: a systematic review and meta-analysis

“…Several in vitro studies have been conducted to evaluate characteristics of universal adhesives (5)(6)(7)(8). Etching mode and thermomechanical loading significantly influenced the marginal integrity of universal adhesives.…”

“…In dentin, the greatest percentage of continuous Original Article Clinical effects of different etching modes for universal adhesives: a systematic review and meta-analysis margin was achieved for Adhese Universal in the ER group (100%) before TML and for both universal adhesives in the SE groups (61%) after TML. Thermomechanical loading did not influence the margin integrity in the enamel, while it did influence the margin integrity in dentin (6). Diniz et al found that etch-and-rinse approach lead to higher bond strength of enamel compared with self-etch approach (9).…”

Hybrid layer formation and bond strength to dentin impregnated with endodontic sealer after cleaning protocols

“…[ 8 9 ] Furthermore, universal adhesive systems combine the advantages of these two etching strategies, which simplify and accelerate the adhesive application. [ 10 ] However, the behavior of universal adhesives to dentin impregnated with endodontic sealers is still uncertain.…”