Another study showed that application of pome- granate peelextract, grapeseedextract, greentea, and sodiumascorbate on enamelbleached with 40% hydro- gen peroxide neutralized the effect of residual oxygen molecules on the bleachedenamel surface, and in- creased the SBS of compositeresin.  The concentra- tion of antioxidants were similar to the current study, but we used 15% carbamide peroxide as the bleaching agent which is weaker than hydrogen peroxide and could produce less residual oxygen molecules. Appar- ently, the effect of antioxidant on the SBS would de- crease as the bleaching agent concentration decreases.
Since, there is a limited information available on the use of the newer natural antioxidant agents like Oligomeric Proanthocyanidin Complexes (OPCs) that they increases the bondstrength of compositeresin to bleachedenamel. OPCs present in natural antioxidants like grapeseedextract and pine bark extract have free radical scavenging activity 4 ,36 . Hence, the aim of this in-vitro study was to evaluate and compare the effect of 10% SodiumAscorbate , 10 % pine bark extract, and Aloevera leaf solution on the SBS of compositeresin to bleachedenamel.
Subramonian et al,  reported that herbal products such as pine bark and grapeseedextract can compensate for the reduced bondstrength of composite to bleachedenamel, and pine bark had a greater efficacy than grapeseed; the results of our study demonstrated similar antioxidative efficacy of greentea and grapeseed, which was in agreement with the results of Sharafeddin et al . However, sage was not evaluated in their study. The current study showed that sage had antioxidant activity and increased the microshear bondstrength of composite to bleachedenamel. The mechanism of action of sage has yet to be fully understood; however, the antioxidant property of this material is due to its polyphenolic nature and chemical formulation. Polyphenols like caffeic acid, hispidulin, apigenin, rosmanol, carnosic acid, carnosol and ursolic acid are among the active ingredients of sage. Similar to other antioxidants, these polyphenols inhibit the formation of reactive oxygen species [22,34]. This finding was in accord with the results of Khamverdi and Safari . Abraham et al,  compared the antioxidant property of sodiumascorbate and grapeseed and concluded that application of grapeseed had greater efficacy for reversal of compromised bondstrength of composite to bleachedenamel; whereas, Arumugam et al,  reported opposite results. It is stated that high molecular weight of proanthocyanidin is an important factor responsible for its less penetration into tooth structure and reducing
Materials and Methods: Forty flat enamel surfaces were prepared from freshly extracted human premolars using a low speed diamond saw. Then the specimens were divided into four random groups (n = 10). All the groups were treated with 30% H2O2. The specimens in Group I were bonded immediately after bleaching, whereas Group II, III and IV were treated with antioxidantsSodiumascorbate, Pomegranatepeelextract and Grapeseedextract respectively. After preparation, a standard shaped resincomposite was applied to all specimens. The teeth were stored in deionized water for 24hrs at 37°C and a universal testing machine determined their shearbondstrength. The data were evaluated using ANOVA and Tukey Post Hoc tests.
Use of nanotechnology for the fabrication of composite resins with unique properties is among the most important achievements in dental material science . It has been documented that nanoparticles have superior physical, chemical, mechanical and optical properties compared to microparticles and they have been used to manufacture dental materials with high mechanical properties and antimicrobial effects . Curcumin is a yellow, active ingredient of turmeric, which is derived from the underground stems of Curcuma longa. It is used not only as a spice, but also as a medicinal herb for treatment of many conditions . Curcumin inhibits the growth and proliferation of many bacterial strains such as staphylococci, lactobacilli and streptococci .
Studies have examined the physical alteration after bleaching to find a possible explanation for decrease in enamelbondstrength caused by bleaching agents. Titley KC et al also suggested that the reduction in bondstrength might be related to the presence of residual hydrogen peroxide at or near the enamel surface which interfered with resin attachment and inhibited resin polymerization. (28) There are more studies that have described this effect. (29,85) The loss of calcium and alterations in the organic substance might be important factors to cause a decrease in enamelbond strengths. (37) Rotstein I et al suggested that bleaching agents changed the original ratio between the organic and inorganic components of the tissues and increased their solubility. (41) Also, Bistey T et al reported that at-home and in-office peroxide- containing bleaching agents are capable of causing structural alteration in enamel at low and high concentrations as well. (62) These studies probably explains the reduction in shearbondstrength after office bleaching.
After inducing diabetes in the control group, the weight loss process increased. The mean weights of the rats in the studied groups are shown in the table as below. As the data in this table and figure 1 show, the weight loss process in the diabetic groups receiving the greentea and Kombucha made from greentea was significantly less than the control group (respectively p = 0.024 and (p = 0.0001). Moreover, the administration of Kombucha prepared from greentea compared with the greentea prevented significantly the weight reduction (p = 0.0001).
In Group 1, the powder and liquid of RMGI was mixed on a wide surface of glass slabs with a powder- to-liquid ratio of 3.2gr:1gr and placed in the cavity em- bedded in the mold. To acquire a smooth surface with- out bubbles, a sheet of celluloid plastic was placed on the surface and then a glass plate was placed on it. Then the samples were cured for 20 seconds with an LED light-curing unit (Demi Plus; Kerr, Switzerland) at a light intensity of 1200 mW/cm 2 according to the manu- facturer’s instructions. The glass plate and celluloid tape were carefully removed and then a layer of Adper Sin- gle Bond 2 (3M ESPE; USA) was applied to the surface by using a micro-brush, gently air-dried, and then cured for 20 seconds. A Teflon cylinder, 5.5 mm in diameter and 3.5 mm in height, was used for the preparation of composite molds. Nano-compositeresin (Filtek Z350; 3M ESPE, USA) was added to the RMGI surface in two layers measuring 1.5×2 mm and cured for 40 seconds. In Group 2, the glass powder in this group contained 25
In the current study, using the caries infiltrant (ICON) before bonding did not significantly change the bondstrength compared to the other groups, although the bondstrength was lower when self-etching primer was used than when phosphoric acid was used for enamel preparation before bonding. This was also observed in the control group; shearbondstrength was lower when self-etching primer was used than when phosphoric acid was used, but this difference was statistically insignifi- cant. Previous studies found a significant increase in the shearbondstrength of Transbond XT adhesive with phosphoric acid and Transbond XT primer when ICON was used before bonding orthodontic brackets to sound enamel  or even to demineralized enamel . The shearbondstrength was also increased when Transbond Plus Self Etching Primer was used instead of the conven- tional phosphoric acid etching to sound enamel . The shearbond strengths recorded in this study were sufficient for clinical use in all the six groups presenting different combinations of adhesive systems and enamel protective agents as well as control groups. The average range of bondstrength was suggested by Reynolds  to be 5.9 to 7.8 MPa for clinical and 4.9 MPa for laboratory performances. In vitro and in vivo stud- ies of SBS are both needed; in vitro measurements of shearbondstrength provide useful information about the bonding efficiency of different types of materials, but the actual performance of these materials can only be evaluated in the environment where they were intended to function . Unfortunately, no one variable or combination of variables that can be mea- sured in the laboratory is perfectly predictive of what might occur when the bonding adhesive is used in the demanding environment of the oral cavity [40-42]. Therefore; in vitro studies are mainly important as a preliminary guide to the clinician, while in vivo stud- ies are needed for evidence-based practice.
2. AloeVera: It is commonly known as Ghrita Kumari, Korphad and Musabbar. It is dried juice of leaves of Aloe barbadensis miller belonging to family Liliaceae. The juice contains Aloe-emodin, barbaloin, isobarbaloin, B-barbaloin, resins, Aloetic acid, homonataloin, aloes one chrysophanic acid, chrysamminic acid, galactouronic acid, saponins. The juice is used as Purgative, Anti-inflammatory, Treatment of burns a itching and uses in skin cosmetics as a protective due to its anti-wrinkle properties. 
Chemical engineers had a tall order creating the SEP. They were tasked with finding a way to etch the enamel surface, much like phosphoric acid, but leave the acid in place and have it also act as a semi-permanent adhesion promoter. 50 The methacrylate group and phosphoric acid were combined into a clever methacrylated phosphoric acid ester in order to etch and prime at the same time. Though this acid has a higher pH than traditional phosphoric acid, the pH does not seem to be a primary determinant in the bondstrength that a SEP is able to attain. 50 Calcium is dissolved by the acid and removed from the hydroxyapatite crystal structure. Instead of rinsing the acid and byproducts away, like with traditional phosphoric acid etching, the calcium complexes with the phosphate group and effectively neutralizes it. The elegant chemical
Materials and Methods: Sixty bar-shaped composite blocks were fabricated and stored in saline for 72 hours. The surface of the samples were roughened by diamond burs and etched with phosphoric acid; then, they were randomly divided into three groups according to the repairing process: Group 1: Silorane composite-silorane bonding agent-silorane composite; group 2: Silorane composite-silorane bonding agent- hydrophobic resin-silorane composite, and group 3: Silorane composite-silorane bonding agent-hydrophobic resin methacrylate- based composite. Repairing composite blocks measured 2.5×2.5×5mm. After repairing, the samples were stored in saline for 24 hours and thermocycled for 1500 cycles. The repair bondstrength was measured at a strain rate of 1mm/min. Twenty additional cylindrical composite blocks (diameter: 2.5mm, height: 6mm) were also fabricated for measuring the cohesive strength of silorane-based composite. The data were analyzed using One-way ANOVA and the post hoc Tukey’s test (α=0.05).
enamel surface preparation techniques, various adhesive systems, and bracket-related factors such as area and design of the bracket base [5,6]. Recent studies have shown that 50% to 75% of patients, experience demineralization of dental surfaces during fixed orthodontic treatment [7,8]. An increase in Streptococcus mutans (S. mutans) and Lactobacillus count has been reported in the oral cavity after the placement of fixed orthodontic appliances . Fixed orthodontic treatment makes oral hygiene maintenance difficult and increases plaque accumulation around brackets and bands, leading to an increased risk of dental caries and formation of white spot lesions (WSLs) [10-12]. In addition, enamel etching weakens the structure of the enamel by decalcification and increases the risk of decays . WSLs result from bacterial activity. S. mutans has been associated with decay and plays a major role in the onset of decays .
Glass-ionomer cement is known for its biomimetic properties, because of its similarity to the mechanical properties of dentine. This, along with the benefits of adhesion and release of fluoride, render it an ideal material in many restorative situations. But due to its reduced mechanical properties it should only be used as a final restorative material in low stress areas, and it must be protected by resincomposite or amalgam in areas of high stress. Resin modified GIC has proved to be a material with improved properties and aesthetics as compared to the conventional glass ionomer. As there is always possibility of fracture at the resin – GIC interface, surface conditioners have been used to enhance the adhesion of the same. This is an in vitro experimental study to investigate the effect of four different conditioners on the shearbondstrength of composite to resin modified glass ionomer.
with the tested resincomposite. It could be noted that the aforementioned studies conducted their investigations using chemically activated composites and reported that they were affected by ZOE bases. More recent publications reported no or minimal effect of ZOE bases on the poly- merization light-cured composites Itskovich et al 56 evalu- ated the effect of two base materials (IRM and Fuji IX) on ﬁ ve composite restoration materials. They reported that, related to microhardness, both ZOE (IRM) and GI (Fuji IX) bases can be used safely as bases under composite restorations. Moreover, He et al 47 examined the elastic modulus and microhardness of resin composites placed above the ZOE base (IRM). They concluded that the ZOE affects the composite microhardness and elastic modulus to a distance of only 100 microns from the interface, and so it can be a suitable material to be used under composites. This was supported also by the work of Anastasiadis et al 57 who evaluated the effect of four cavity base materials (Equia- ﬁ l, Angelus white MTA, Biodentin, and IRM) on the surface properties (morphology, roughness, microhardness, compo- sition) and bondstrength to a composite. They also reported that resin bonding to IRM is a reliable method when etch and rinse procedures are applied. Alternatively, self-etch adhesives with mild pH may be used, but with less bonding reliability.
Several materials, such as fluoride, xylitol, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), and bioactive glasses, and several products, such as toothpastes and varnishes, are used to enhance enamel remineralization. Amorphous calcium phosphate (ACP) in combination with casein phosphopeptide (CPP) has shown positive clinical efficacy for the prevention of enamel white spot lesions . In the process of enamel remineralization, ACP is used as a mediator for the formation of hydroxyapatite . ACP is the first deposited phase in the supersaturated solution of calcium phosphate . In the acidic oral environment, we can benefit from the calcium and orthophosphate ion release potential of ACP by the application of bio- composites containing ACP; these ions play a role in remineralization .
Structural differences between normal and fluorotic teeth can influence the bondstrength of composite resins to enamel. Fluorosed and normal teeth in this study were classified according to the TFI, which is based on histopathological changes in relation to clinical manifestations of fluorosed teeth . The teeth classified as TFI =4-6 appear to be chalky and show distinct pit hole defects. Also, sometimes the deep subsurface lesions necessitate the use of a more complex treatment such as composite or porcelain laminate veneering to achieve optimal esthetic results .
In the present study, caries free, unrestored human permanent molars were used as per the guidelines of the International Standards Organization (ISO/technical committee 106/ SC1/ WGII, 1991) . Durafill VS, Ceram X and Esthet X were used as the microfilled, nanofilled and microhybrid composites respectively as these materials are easily available in the local market and are manufactured by companies of international repute. The shearbondstrength testing was done with the help of computerized Universal Testing Machine (Unitek No. 9450, PC, FIE, India) using wire loop method at a crosshead speed of 1 millimeter per minute. This is similar to the method employed in previous studies .
The research question of this study is still questionable in the literature, since while some studies demonstrate that adhesive procedures should not be performed immedi- ately or even after a few days or weeks after bleaching [10–15, 23], other studies state that there is no need to wait a specific time interval to proceed with the restorative treat- ment [13, 16, 17]. These divergent results may perhaps be material-dependent, that is, the bonding process to bleached teeth depends on the type of whitening agent used [13, 24], as well as on the type of adhesive systems and/or restorative materials applied . Regarding to the “whitening agent” factor, materials may vary according to their hydro- gen peroxide concentration, time of application, and pH of the gel; considering that only pH would more importantly influence SBS, the present study also evaluated the mor- phology of enamel after bleaching. According to the SEM imagens shown in Fig. 2, the gel exposed the prism rods of enamel in a similar way that phosphoric acid does. More- over, a clear rougher surface could be observed when compared to the non-bleached specimen.
The lipids oxidize, but instead of forming carbonyls and other compounds associated with rancidity, they become bound up in lipid-protein complexes, which accounts for the toughened texture of over stored or poorly stored frozen fish (Castell, 1971). The changes in protein due to freezing mainly occur in myofibrillar proteins, which undergo denaturation and aggregation through protein–protein bonding. Also, these changes are associated with lipid oxidation occurring during frozen storage. However, texture and functionality alterations observed in the muscle of fatty and semi fatty species are smaller than in lean species due to the protective effect of lipids in proper concentration and location on protein (Tejada, 2001).