Can long-term dentine bonding created in real life be forecasted by parameters established in the laboratory?

Abstract

Tooth-coloured plastic dental fillings secured by adhesives to tooth structures are widely used to fix decayed teeth. Whereas laboratory tests demonstrate rapid deterioration of the ability of the adhesives to stick to dentine, clinical studies show that these fillings are relatively durable. This discrepancy suggests that the parameters used for simulating bond degradation in the laboratory setting do not correlate well with clinical outcomes. The present study examined the long-term tensile bond strength of resin composite fillings performed in real life and under different laboratory-simulated bonding conditions to identify parameters that may be used to forecast the durability of adhesive bonds created in dentine. Fillings placed in vivo were subjected to different periods of intraoral function. In vitro specimens were bonded based on whether simulated pulpal pressure (SPP) or thermomechanical cycling was implemented, and how long the completed fillings were stored in water. Thermomechanical cycling used in combination with long-term water ageing are useful in forecasting the decline in strength of resin-dentine bonds created in vivo. These parameters should be adopted for future evaluations. Conversely, the use of SPP does not appear to be a significant parameter in the simulation of long-term clinical deterioration of bond integrity.

No-waiting dentine self-etch concept—Merit or hype

“…Thermal, mechanical or thermomechanical cycling may be conducted to simulate changes in materials caused by intraoral functioning and ageing [50]. A recent study examined the long-term tensile bond strength of resin composite fillings performed in real life and under simulated ageing conditions to identify parameters that may be used to forecast the durability of resin-dentine bonds [51]. Based on the results of that study, a thermomechanical cycling protocol consisting of 10,000 thermal cycles and 240,000 mechanical cycles was used in the present study, corresponding to one year of intraoral functioning [30,31].…”

Bonding Performance for Repairs Using Bulk Fill and Conventional Methacrylate Composites

“…In the oral cavity, restorative materials are subject to frequent pressure changes through chewing and biting, temperature changes, and electrolyte degradation due to the movement of salivary and microbiota fluids [ 24 ]. Commonly used in dentistry, the artificial aging of the samples in this study was done by thermocycling, following a previous protocol suggestive of 1 year of function [ 24 , 42 ]. Future studies might include prolonged periods and evaluate the longevity of the repaired restoration.…”

“…Artificial aging was carried out by thermocycling (Erios, São Paulo, São Paulo, Brazil) with 10,000 cycles at 5°C/55°C, with a dwell time of 25 sec and an exchange interval of 5 seconds, totaling 30 seconds [ 24 ].…”

In Vitro Evaluation of Experimental Self-Adhesive Orthodontic Composites Used to Bond Ceramic Brackets

“…The main mechanism proposed for such degradation is the water breakdown of ester bonds in methacrylates, which is a link prone to hydrolysis over time. Although it is a challenge for researchers, thermocycling is a widely used method for aging samples in vitro and might have simulated well the period of orthodontic treatment herein; after this period, the bracket needs to possess lower bond strength to ease removal without damaging the enamel structure [26].…”