Bond Stability of Universal Adhesives Applied To Dentin Using Etch-And-Rinse or Self-Etch Strategies

Abstract

This study evaluated the immediate and 6-month dentin bond strength of universal adhesives used in etch-and-rinse or self-etch bonding strategies. The adhesives tested were Ambar Universal, G-Bond, Single Bond Universal, Tetric N-Bond Universal, and Ybond Universal. Gold standard adhesives (Scotchbond Multipurpose Plus and Clearfil SE Bond) were controls. Microtensile dentin bond strength (n=5 teeth), pH, and C=C conversion (n=3) were evaluated. Data were analyzed at α=0.05. All adhesives showed differences in pH. Ybond had intermediately strong aggressiveness, whereas the others were ultra-mild. The C=C conversion was different in most adhesives. In the etch-and-rinse strategy, all adhesives showed similar results generally except for G-Bond, which had lower bond strength than most adhesives. G-Bond and Tetric-N-Bond showed lower bond strengths after 6 months compared with 24 h, whereas the other adhesives had stable dentin bonds. In the self-etch strategy, G-Bond had lower bond strength than most adhesives. After 6 months, Ambar was the only adhesive showing lower dentin bond strength compared with 24 h. Most adhesives had discreet drops in bond strength during aging when used in the self-etch strategy. The failure modes were also material dependent, with a general pattern of increased adhesive and/or pre-testing failures after storage. In conclusion, the bonding performance of universal adhesives to dentin is material dependent. Most adhesives had stable dentin bonds with results comparable to the gold standard materials, particularly when applied in the self-etch mode. In general, it seems the use of universal adhesives in dentin should not be preceded by phosphoric acid etching.

Bonding Effectiveness of Bioactive Self-Adhesive Restorative Material to Enamel and Dentin Using Different Bonding Protocols

“…This was confirmed by the ESEM finding as shown in fig.2D. This finding was in accordance with De Cardoso et al, 2019 (23) who demonstrated a drop in bond strength results to etched dentin after storage. Armstong et al, 2017 (24) , stated that 6 m storage for testing dentin bond strength is considered a medium to long term aging period.…”

“…Moreover, phosphoric acid might result in formation of deep microporosities greater than the resin infiltrating potential leaving unprotected collagen fibers which are highly vulnerable to both hydrolytic and enzymatic degradation. (23,25) In addition, activation of matrix metalloproteinase enzymes (MMPs) due to dentin etching using such aggressive phosphoric acid might be another explanation for the diminished durability of microshear bond strength results. (23) Bonding to dentin using self-etch mode demonstrated stable bond strength results at 6 m storage which was also demonstrated in fig.…”

Influence of etching mode and composite resin type on bond strength to dentin using universal adhesive system

“…On the other hand, it is common to find different products combined in previous research studies. This may be one of the explanations for the discrepancy in results since it has previously been determined that bond strength is highly product‐dependent and that different combinations of adhesives and composite resins may perform better than others (Cardoso, Nakanishi, Isolan, Jardim, & Moraes, 2019). The mold used in this study did not allow light to penetrate the composite from the side but only from the top.…”

Factors involved in the stability and durability of adhesive in the dentin.

“…Universal adhesives can produce moisture control without drying out, and to improve this bond, the application of a second layer of adhesive on the dentin is recommended. 3,5,[8][9] Dentin dehydration can affect the mechanical properties of the hybrid layer. 6,8 Dentin smear produced by cavity preparation also hinders the impregnation of the adhesive.…”