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

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.

Which surface treatment improves the long-term repair bond strength of aged methacrylate-based composite resin restorations? A systematic review and network meta-analysis

“…The sample sizes varied between 5 [43] to 61[30] in each study. The aging methods included liquid storage (water [3, 9, 27, 44, 45] and saliva [46]), thermocycling [20, 22-25, 29, 31, 32, 42, 47], or a combination of the two [21, 26, 28, 30, 43, 48]. Seven studies [22-25, 30, 43, 46] provided micro-tensile bond strength, four [3, 9, 44, 47] indicated micro-shear bond strength, ten [20, 21, 26-29, 31, 32, 42, 48] gave shear bond strength, and only one [45] evaluated tensile bond strength.…”

“…The surface treatment protocols performed on old composite resins also play a significant role in determining the durability of the repair bond. Invitro research findings had also utilized a variety of surface treatment methods, such as roughening with abrasive papers [20][21][22][23], diamond burs [24][25][26], Al 2 O 3 particles [3,22,27], silica coated particles [28][29][30], and lasers [31,32] as mechanical; and numerous bonding mechanisms, adhesives, and salinization as chemical surface treatments [3,22,23,27], solely or in combination to overcome the bonding obstacles. The main objective of such surface modifications is to produce a strong bond through the micromechanical interlocking between fresh and old composite resins.…”

Title: Evaluation of Glass Ceramic Bond Strength to Different Foundation Materials

“…[13] Several studies have evaluated the effectiveness of this method. [29][30][31] However, air abrasion can activate the formation of cracks and surface damage and compromise the core mechanical characteristics. Therefore, it is recommended to use small particles with a diameter between 30 and 50 µm, moderate pressure (2.5 bar), for 10 sec and at 10 mm from the target as performed in this study.…”

Comparative Evaluation of the Repair Bond Strength of Dental Resin Composite after Sodium Bicarbonate or Aluminum Oxide Air-Abrasion

“…Supporting the observed µTBS values in this study, SEM images showed an irregular topography pattern after surface treatment using 53 µm aluminum oxide. Structural changes, such as the destruction of both the resin matrix and filler particles, may lead to a better micromechanical interlocking between the substrate and repair RBC after surface treatment with aluminum oxide particles [36]. Aluminum oxide as the standard abrasive powder for use in air-abrasion has a Mohs hardness index of 9, which is strong enough to remove the contaminated superficial layer of RBC via the non-selective destruction of the RBC compartments (see Figures 4 and 5).…”