The Influence of Temperature of Three Adhesive Systems on Bonding to Ground Enamel

Abstract

The temperature of adhesive systems must be considered an important factor for the good clinical performance of bonding procedures. SUMMARYThis study evaluated the microtensile bond strength test (µT), micromorphology of resinenamel interface (RET) and etching patterns (EP) promoted by the etch-and-rinse adhesive, Prime&Bond NT (PB), and two self-etching adhesives, Clearfil SE Bond (SE) and Adper Prompt LPop (APR), to ground bovine enamel surfaces, when applied at temperatures of 5°C (C), 40°C (H) and 20°C (R). Materials and Methods. Sixty-three bovine incisors were randomly divided into nine experimental groups (n=7) according to adhesive systems and temperatures. The buccal enamel surfaces were flattened with 600-grit SiC paper and abraded with a diamond bur under watercooling. The adhesive systems were applied according to the manufacturer's instructions. After the restorative procedures, the specimens were sectioned into five slabs. Four slabs were prepared for µT and one for interface analysis. For etching pattern analysis, the remaining 16 bovine enamel fragments were used (n=2). The adhesives were applied and the surfaces were rinsed with organic solvents after application. The specimens for RET and EP analysis were prepared for SEM analysis. Results. No significant differences among the adhesives were found at R temperature. However, at 5°C, PB and APR presented lower bond strength than SE. At H temperature, higher bond strength was observed for PB than for APR and SE. At C and H temperature, formation of the interdiffusion zone was impaired and the treated enamel surfaces presented an undefined EP.

Effect of agitation and storage temperature on water sorption and solubility of adhesive systems

“…The advent of adhesive systems has promoted meaningful changes in restorative procedures, since current bonding agents exhibit better clinical performance 10) . However, regarding the simplified bonding systems, long-term adhesive stability is still a major challenge.…”

“…The higher hydrophilicity and possible presence of residual solvent in the simplified adhesive agents means that care is needed to ensure the bonding layer has optimum mechanical properties 8) . A frequent recommendation is to store the adhesives at room temperature since changes in temperature may influence bonding 10) . The storage temperature can modify the viscosity of the polymeric material, increasing the penetration capacity, dissolution, time of solvent evaporation and degree of conversion, which might impact on the physical and mechanical properties of the bonding agents 11) .…”

Influence of a heating device and adhesive temperature on bond strength of a simplified ethanol-based adhesive system

“…An electronic display was used to maintain a controlled temperature, and a heating chamber housing the adhesive bottle allowed the temperature to rise to a controlled 37°C. Adhesives can be heated to appropriate levels by directing warm air from a special three-way syringe or hair dryer after application 7,15,16 . Simple drying cabinets with temperature control displays can also be used.…”

“…It is widely accepted that the polymerization rate of adhesive systems is also improved by a temperature rise up to 60°C, which promotes a more stable and less degraded resin-dentin interface over time, whereas low temperatures have a negative impact on both aspects [7][8][9]11 .…”

“…Bonding effectiveness of adhesive systems may be associated with their temperature of application. Increased adhesive temperature promotes superior solvent evaporation and reduces the adhesive viscosity, hypothetically ensuring a stable and lasting bond [6][7][8][9][10][11][12] . Enhanced solvent evaporation limits the residual solvent 13 , enhances wettability 11,14,15 -which influence the hybrid layer formation positively 16 -and yields a highly reticulated polymer, with reduced water sorption and lower hybrid layer solubility 17 .…”