Effect of Varying Working Distances between Sandblasting Device and Composite Substrate Surface on the Repair Bond Strength.

Phoebe Burrer,Amanda Costermani,Thomas Attin,Matej Par,Tobias T Tauböck

doi:10.3390/ma14071621

Phoebe Burrer, Amanda Costermani + Show 3 more

Open Access

https://doi.org/10.3390/ma14071621

Copy DOI

Abstract

This study investigates the effect of defined working distances between the tip of a sandblasting device and a resin composite surface on the composite–composite repair bond strength. Resin composite specimens (Ceram.x Spectra ST (HV); Dentsply Sirona, Konstanz, Germany) were aged by thermal cycling (5000 cycles, 5–55 °C) and one week of water storage. Mechanical surface conditioning of the substrate surfaces was performed by sandblasting with aluminum oxide particles (50 µm, 3 bar, 10 s) from varying working distances of 1, 5, 10, and 15 mm. Specimens were then silanized and restored by application of an adhesive system and repair composite material (Ceram.x Spectra ST (HV)). In the negative control group, no mechanical surface pretreatment or silanization was performed. Directly applied inherent increments served as the positive control group (n = 8). After thermal cycling of all groups, microtensile repair bond strength was assessed, and surfaces were additionally characterized using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The negative control group reached the significantly lowest microtensile bond strength of all groups. No significant differences in repair bond strength were observed within the groups with varying sandblasting distances. Composite surfaces sandblasted from a distance of 1 mm or 5 mm showed no difference in repair bond strength compared to the positive control group, whereas distances of 10 or 15 mm revealed significantly higher repair bond strengths than the inherent incremental bond strength (positive control group). In conclusion, all sandblasted test groups achieved similar or higher repair bond strength than the inherent incremental bond strength, indicating that irrespective of the employed working distance between the sandblasting device and the composite substrate surface, repair restorations can be successfully performed.

Highlights

Repair restorations are widely acknowledged as a valid alternative to total replacement of partially insufficient composite restorations and have gained immense popularity over the last decades [1,2]
This study investigates the effect of defined working distances between the tip of a sandblasting device and a resin composite surface on the composite–composite repair bond strength
Composite surfaces sandblasted from a distance of 1 mm or 5 mm showed no difference in repair bond strength compared to the positive control group, whereas distances of 10 or 15 mm revealed significantly higher repair bond strengths than the inherent incremental bond strength

Summary

Introduction

Repair restorations are widely acknowledged as a valid alternative to total replacement of partially insufficient composite restorations and have gained immense popularity over the last decades [1,2]. In order to achieve adequate repair bond strength, mechanical and chemical pretreatment of the existing composite surface is mandatory. Sandblasting of the composite surface is often considered a necessary treatment step of repair procedures [16] and can either be achieved by air abrasion with aluminum oxide particles (Al2O3) or silica coating [17,18,19]. Both procedures are accepted, the use of Al2O3 is more common and has been proven to enhance repair bond strength [13]. The use of Al2O3 over silica-coated particles is preferable, since reduced marginal composite adaptation has been observed for dentin surfaces unintentionally contaminated with silica particles during air abrasion in the course of repair procedures [17]

Objectives

Methods

Results

Conclusion