*Corresponding author: Ibrahim M Hamouda, Faculty of Dentistry, Umm Alqura University, Saudi Arabia, Tel: +966 537924044; E-mail: Imh100@hotmail.com Citation: Al-Towairqi WA, Hamouda IM (2017) Effect of Instrument Lubricant on Water Sorption and Solubility of Incrementally Applied Nanofilled Resin Composite. J Nanotechnol Nanomed Nanobiotechnol 4: 019. Received: September 19, 2017; Accepted: October 18, 2017; Published: No- vember 03, 2017 Introduction Tooth colored restorations were introduced to the feld of dentistry over 40 years ago. In 1995, silicates were used as a restorative materi- al followed by Polymethyl Methacrylate (PMMA) with its properties of ease of manipulation, insolubility in oral environment. In order to overcome these problems quartz powder particles were added to form a composite structure, it reduced the volume of the resin and thus re- duced thermal expansion and contraction to approach the coeffcient of thermal expansion of the tooth [1]. In 1962, a new type of composite materials was developed based on using bisphenol-A Glycidyl dimethacrylate (bis-GMA) a mono- mer that forms a cross-linked matrix and a surface treatment using silane coupling agent to bond the fller particles and the resin matrix which may decrease water sorption and solubility [1]. Composite was originally indicated for application in anterior teeth only, with later improvements in mechanical properties it was accepted to be used in posterior teeth too [2]. Resin composite has optical characteristics that mimic the tooth structure [1]. With recent advances in adhesive technology it became one of the most used restorative materials [3]. Many advances have been made to improve the properties of resin composite increasing the fller loading is one, it improves aesthetics and leads to reduction in polymerization shrinkage, water sorption and generally improves mechanical and physical properties [1]. Clas- sifcation of dental composite was made according to the particle size of inorganic fller, based on this, it’s divided into three main types: macroflled, microflled and hybrid composite, recent development of composite include nanocomposites, with (0.01 μm) fller size, these composite have superior optical characteristics and polishibility, im- proved strength and reliability compared with microflled composite [1,4,5]. Resin composite must be placed incrementally to overcome the problem of polymerization shrinkage and to ensure that the material is fully polymerized [6]. A phenomenon known as the air-inhibiting layer makes incremental building up possible [7-9]. It is believed that oxygen inhibits polymerization of a thin superfcial layer of resin composite. Thus, supplies double methyl methacrylate bond for copo- lymerization with another increment of the resin [10,11]. Diffculties with incremental building up of resin composite are adherence of the material to the instrument during application [12]. Despite the many advances in dental composite, its stickiness is still one of its major disadvantages [13]. Resin composite adheres to the instrument during insertion and condensation as reported by many cli- nicians [14,15]. Thus, increases the risk of voids and porosities in the fnal restoration, many techniques have been developed to overcome this issue, including development of plastic-ended, titanium coated instrument [16,17]. Another technique involves wiping the instrument with isopropyl alcohol-saturated gauze before sculpting composite [18]. Lubricating the instrument with unflled adhesive resin before sculpting composite is also a will known technique used to overcome composite adherence. It has been agreed that using lubricant adversely Al-Towairqi WA, J Nanotechnol Nanomed Nanobiotechnol 2017, 4: 019 DOI: 10.24966/NTMB-2044/100019 HSOA Journal of Nanotechnology: Nanomedicine & Nanobiotechnology Research Article Abstract The stickiness of nanoflled resin composite is still one of its ma- jor disadvantages that haven’t been corrected yet. Many techniques have been developed to overcome this issue, including the use of bonding agent as instrument lubricants. This research aimed to com- pare between 2 bonding agents when used as instrument lubricants and their effects on water sorption and solubility of nanoflled resin composite according to the number of increments applied. A total of 45 samples of nanoflled resin composite were prepared and di- vided into three groups according to the used instrument lubricants. The specimens were divided based on the number of increments applied (2, 3 and 4 increments). Water sorption and solubility were measured using calibrated electronic microbalance. Resin compos- ite applied with 1-step adhesive system (5 th generation) and 2-steps adhesive system (7 th generation) showed a signifcant difference of water sorption when compared with nanoflled resin composite applied without lubricants. Resin composite applied with both lubri- cants showed insignifcant difference in solubility when compared to nanoflled resin composite applied without lubricants. It was con- cluded that, using adhesive resin as instrument lubricants for nano- flled resin composite showed a signifcant effect on water sorption of the specimens. There was insignifcant effect on the solubility of the nanoflled resin composite after using of the adhesive resin as instrument lubricants. Keywords: Incremental application; Lubricants; Nanoflled compos- ite resin; Resin adhesives Wala’a Abdulkarim Al-Towairqi 1 and Ibrahim M Hamouda 2* 1,2 Faculty of Dentistry, Umm Alqura University, Saudi Arabia 2 Faculty of Dentistry, Mansours University, Egypt Effect of Instrument Lubricant on Water Sorption and Solu- bility of Incrementally Applied Nanofilled Resin Composite