# Resin-Based Cement Applied to Enamel and Dentin Pre-Treated with Phytic Acid: An In Vitro Study
###### Abstract  
Phytic acid (IP6) has the ability to etch tooth structure due to its acidity and chelating properties. This study aimed to evaluate the micro-tensile bond strength (uTBS) of resin-based cement to enamel and dentin using manufacturer-provided etchans, phosphoric acid (PA) for enamel and a mixture of 10% citric acid and 3% ferric chloride (CAF) for dentin and compare them to IP6. Enamel surfaces were etched for 30 s with either PA or IP6 (1%, 5% or 10%). Dentin surfaces were etched for 15 s with either CAF or 1% IP6. Pre-polymerized composite blocks were bonded to enamel and dentin surfaces. After 24 h, the specimens were sectioned into beams and subjected to uTBS testing. De-bonded specimens and smear layer removal were analyzed with a scanning electron microscope. Etching enamel with 1% and 5% IP6 resulted in uTBS values that are comparable to the control (PA) (\(p>0.05\)), while 10% IP6 negatively affected the uTBS (\(p<0.05\)). The uTBS to dentin etched with 1% IP6 was higher compared to the control (CAF) (\(p=0.001\)). IP6 effectively removed enamel and dentin smear layer, and at specific concentrations, it may be a suitable alternative conditioner agent for bonding resin-based cement to enamel and dentin.  
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citric acid and 3% ferric chloride (CAF) [5]. Previous studies reported that the application of a 10% citric acid and 3% ferric chloride solution for dentin etching contributes to high bond strength to dentin [6] and excellent clinical retention rates for methacrylate-based adhesives [7]. Some 4-META-based self-etching adhesive resin cements (such as M-Bond, M-Bond II by Tokuyama Dental) have been introduced with the ability to etch both enamel and dentin simultaneously. Despite these advantages offered by such materials, there are several concerns regarding bond durability to dentin [8].  
Phytic acid, which is also known as inositol hexa-phosphate (IP6), can be extracted from various plant seeds [9]. IP6 possesses a strong negative charge [10], which can chelate the positively charged cations and precipitate in the form of a complex salt at neutral pH [11], but soluble in acidic conditions. An initial interest in IP6 employed in dentistry started several decades ago with the identification of its cariostatic, anti-calculus and antiplaque ability, as well as to its cement-forming properties and its ability to reduce enamel dissolution [12; 13; 14; 15]. However, it is only recently that such interest in IP6 has increased with the exploration of new applications in endodontics [16; 17; 18; 19; 20] and adhesive dentistry [21; 22; 23]. In 2013, IP6 was proposed as an effective etchant, which resulted in higher bond strength to dentin and a lower cytotoxic effect on pulpal cells when compared to PA [21].  
To the best of our knowledge and in view of the most recent available literature, there is little information about the effect of IP6 on etching and bonding to enamel and its effect on the adhesion of resin-based cement to dentin. Thus, the aim of this study was to evaluate the micro-tensile bond strength (\(\upmu\)TBS) of resin-based cement to enamel and dentin using IP6 prior to bonding and compare it to that of conventional agents provided by the manufacturer of PA for enamel and CAF for dentin. The null hypotheses tested were (1) there would be no difference between the bond strength of the resin-based cement applied on enamel etched using the manufacturer-provided agents (PA) or the different concentrations of IP6 and, (2) there would be no difference between the bond strength of the MMA-based resin cement to manufacturer-provided (CAF) or IP6-etched dentin.