Shahin Kasraei

Shahid Beheshti University of Medical Sciences · Department of Restorative Dentistry

The heat generated in the process of light curing may cause irreversible damage to the dental pulp. This study aimed to assess heat transfer in the process of irradiation of a dentin disk by using different modes of quartz-tungsten halogen (QTH) and light-emitting diode (LED) dental curing units. The surface temperature was measured by an infrared...

The heat generated in the process of light-curing may cause irreversible damage to the dental pulp. This study aimed to assess heat transfer in the process of irradiation of a dentin disc by using different modes of quartz-tungsten halogen (QTH) and light-emitting diode (LED) dental curing units. The surface temperature was measured by an infrared...

Precise information regarding the thermal properties of human tooth structure such as its thermal conductivity and diffusivity can increase the accuracy of heat transfer modeling, which has recently gained popularity. Moreover, such information is highly important for designing and production of dental materials. Since thermal conductivity and diff...

Precise information regarding the thermal properties of human tooth structure such as its thermal conductivity and diffusivity can increase the accuracy of heat transfer modeling, which has recently gained popularity. Moreover, such information is highly important in the designing and production of dental materials. Since the thermal conductivity a...

Aim: This study was fulfilled to evaluate the flexural strength, micro-hardness, and release of two fluoride ions of bioactive restorative materials (Cention N and Activa Bioactive), a resin modified glass ionomer (Fuji II LC), and a resin composite (Filtek z250). Methods: Forty samples from four restorative materials (Activa Bioactive, Fuji II LC,...

Objectives This study compared the cuspal deflection and marginal microleakage following the application of bulk-fill and conventional composite resins. Materials and Methods 70 sound premolars with MOD preparation were randomized into 5 groups (n = 14). In three groups, the cavities were restored with Tetric Ceram N, X-tra fil, and Opus bulk-fill...

Purpose: To evaluate the effects of C-factor on the bond strength of universal adhesives to floor and wall dentin in class-I composite restorations using a bulk-fill composite. Materials and methods: 108 non-carious humans third molars were randomly divided into four groups as follows: flat wall, flat floor, cavity wall, and cavity floor (n = 36...

Objectives: This study investigated the microhardness, flexural strength, and color stability of bleach-shade resin composites cured with 3 different light-curing units. Materials and methods: In this in vitro experimental study, 270 samples were fabricated of bleach and A2 shades of 3 commercial resin composites (Point 4, G-aenial Anterior, and...

Demineralization is a common problem following orthodontic treatments. Today using antibacterial nanoparticles in preventing white spot lesions is being discussed. Given that ZnO and TiO 2 nanoparticles have direct antibacterial known properties, this study aims to evaluate these nanoparticles' antibacterial effects in orthodontic bondings' composi...

Knowledge about the thermal properties of human teeth is imperative for accurate understanding of heat transfer in dentistry. Despite the presence of specific heat in thermal conduction and heat transfer equations, and requiring this parameter for calculation of conductivity based on diffusivity, adequate attention has not been paid to experimental...

Background. Diet and lifestyle can destroy tooth structure due to the dissolution of enamel by acidic beverages. The present study evaluated the effect of CO2 laser irradiation and CPP-ACFP (casein phosphopeptide and amorphous calcium phosphate with fluoride) paste on the remineralization of enamel eroded by carbonated soft drinks. Methods. In the...

Aim: Several new bioactive compounds were recently introduced to the market with favorable ion release, tooth remineralization, and alkalizing potential. This study sought to compare the phosphate ion release and alkalizing potential of three bioactive materials in comparison with composite resin. Methods: Thirty-six discs (2 × 6 mm) were fabric...

Aim: Recent reports indicate that deproteinization of acid-etched dentin surface can extend penetration depth of adhesive agents. The main goal of the present research was to investigate the deproteinization effect of Nd:YAG and diode 940 lasers on acid-etched dentin and microleakage grade in class V composite restorations. Methods: 36 extracted hu...

Background: Studies show that fluoride (F) and nano‑hydroxyapatite (nano‑HA) would result in remineralization of white spot lesions (WSLs), which are among the most prevalent consequences of fixed orthodontic treatment. The present study evaluates and compares the clinical effects of an Iranian toothpaste containing nano‑HA with F‑containing one on...

Objectives: It has been reported that bulk-fill composites simplify tooth restoration with no adverse effect on the success rate. This study sought to assess the cuspal deflection of premolars with mesio-occluso-distal (MOD) cavities restored with bulk-fill and conventional posterior composite resins. Materials and Methods: This in-vitro experiment...

Heat transfer occurs frequently in numerous dental treatment procedures. In almost all of the related experimental studies, use of infrared camera for temperature measurement, is becoming more and more popular, considering the many advantages of this technique. This technique has been employed in some recent studies as a non-invasive method for dis...

A B S T R AC T Introduction: The removal of collagen by chemical methods can effectively decrease the marginal microleak-age of composites used in restorative dentistry. Objectives: To present research focused on the assessment of the impact of surface treatment of dentin with 5% bromelain and 5% trypsin on the microleakage of composites. To presen...

Introduction: Some studies have shown that laser irradiation on unpolymerized adhesives can improve composite-dentin adhesion. The aim of the present study was to evaluate the effect of the Diode laser (810 nm) on the microleakage of multi-mode adhesive systems at enamel and dentin margins of composite restorations. Methods: Classic Class V boxes...

Background: The cross-linking of collagen fibers in the hybrid layer has been suggested as a way to create more durable bonds. Objectives: This study evaluated the effect of visible light-activated riboflavin (RF) as a cross-linking agent on the durability of the dentin microtensile bond strength (μTBS) in a 2-step self-etch (SE) adhesive system...

Statement of the problem: Laser can influence bonding mechanism by increasing the penetration depth of adhesive in smear layer. The effect of 940 nm diode laser on microtensile bond strength of adhesive to dentin has not been investigated in previous studies. Purpose: The aim of this study was to evaluate the effect of 940 nm diode laser irradia...

Introduction: It has been suggested that the application of casein phosphopeptide-amorphous calcium phosphate paste (CPP-ACP) and CO2 laser irradiation on enamel could increase the resistance of enamel to caries and acid attacks. The aim of the current study was to compare the influence of CPP-ACP paste application and irradiation of CO2 laser on m...

Background: Bitewing radiography is an important modality useful for the evaluation of teeth in patients of various ages and in different stages of tooth eruption. Clinical examination of proximal surfaces for caries may result in false negative results, especially in tight contact areas. Thus, radiography, as an adjunct to clinical examination, i...

Introduction: Nowadays, the main focus of dental studies is on adhesive dental materials; since clinical long-term success of bonded restorations depended more on marginal microleakage minimization. So, the aim of this study was Evaluation of Diode laser irradiation effect on microleakage in class V composite restoration before and after adhesive a...

Objective: this study aimed to assess the effect of treatment of phosphoric acid etched dentin surface with 5% bromelain enzyme and Nd:YAG laser prior to the use of etch and rinse adhesive systems on microleakage margins of class V composite restorations. Materials and Methods: sixty sound premolar teeth were selected. Standard class V cavities wer...

Background and Objectives Image processing and enhancement filters can significantly improve the diagnostic value of digital radiographs. Evidence shows that increasing the contrast and filtering improve the diagnostic accuracy for caries detection. This study sought to assess the diagnostic accuracy of original and enhanced digital radiographs for...

The aim of this study was to evaluate the effect of dentinal tubules orientation on the composite-dentin microtensile bond strength using universal adhesives. A total of 36 caries-free third molars were selected. The teeth were allocated to (axial, wall) and (occlusal, floor) groups and each group was divided into three subgroups based on the type...

Low-level laser therapy (LLLT) is a non-invasive modality to promote osteoblastic activity and tissue healing. The aim of this study was to evaluate the efficacy of LLLT for improvement of dental implant stability. This randomized controlled clinical trial was performed on 80 dental implants placed in 19 patients. Implants were randomly divided int...

Objectives: Laser irradiation, as an adjunct to root canal preparation, may increase the success rate of endodontic treatments. This study aimed to assess the effect of neodymium-doped yttrium aluminum garnet (Nd:YAG) and diode lasers on the apical seal of the root canals filled with AH Plus® and mineral trioxide aggregate (MTA)-based sealers. Ma...

Introduction: Successful repair of composite restorations depends on a strong bond between the old composite and the repair composite. This study sought to assess the repair shear bond strength of aged silorane-based composite following surface treatment with Nd:YAG, Er, Cr:YSGG and CO2 lasers. Methods: Seventy-six Filtek silorane composite cylinde...

Introduction: Previous studies have revealed the effectiveness of laser therapy in the improvement of dentin bonding. In other words, laser radiation can result in the higher bond strength of adhesives. Accordingly, the aim of this study was to propose an appropriate protocol for the use of Er:YAG and Nd:YAG lasers with the purpose of improving the...

Background and Objectives: Previous studies have shown that increasing collagen resistance to degradation stabilizes the resindentin interface and collagen cross-linkers can prevent the degradation of collagen fibrils as such. This study sought to assess the efficacy of light-activated riboflavin for collagen cross-linking and optimizing the micro...

Secondary caries is the most common cause of dental restoration failures. This study aimed to compare the diagnostic accuracy of conventional and digital intraoral radiography and cone beam computed tomography (CBCT) for detection of recurrent caries around composite restorations. mesio-occluso-distal (MOD) cavities were prepared using bur on 45 ex...

Introduction: The purpose of the present study was to evaluate the different concentrations of sodium hypochlorite activated with laser in removing of the smear layer in the apical, middle, and coronal segments of root canal walls by scanning electron microscopy analysis. Methods: Sixty single-rooted human mandibular teeth were decoronated to a sta...

Introduction: The characteristics of a suitable restoration material is having acceptable mechanical properties, protecting teeth against decay and ease of use in clinics. Diet can affect properties of restorative materials in the mouth. Since amongst important properties of composite restorations are mechanical properties such as hardness, the aim...

The aim of the present study was to evaluate the success rate of failed implants re-implanted after surface treatment with CO2 laser. Despite the widespread use of dental implants, there are many incidents of failures. It is believed that lasers can be applied to decontaminate the implant surface without damaging the implant. Ten dental implants th...

Introduction: This study aimed to compare the microshear bond strength of composite to enamel treated with Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) laser using a self-etch one step bonding agent. Methods: Seventy-six enamel surfaces were prepared from 38 sound human third molar teeth. Specimens were randomly divided into four groups of 18. The...

Objectives: Because of poor bond between resin cement and zirconia ceramics, laser surface treatments have been suggested to improve adhesion. The present study evaluated the effect of CO2 and Nd:YAG lasers on the shear bond strength (SBS) of resin cement to zirconia ceramic. Materials and methods: Ninety zirconia disks (6×2 mm) were randomly di...

Introduction: Bleaching materials may influence the physical properties of resin composite restorations such as surface free energy. High surface free energy causes plaque accumulation and is an important factor for adhesion of bacteria to surfaces. The purpose of this study was to compare the surface free energy of Methacrylate-based Resin Composi...

Introduction & Objectives: Surface roughness affects beauty, hygiene, plaque retention and health of the gingival adjacent to the composite restoration. Many people use bleaching agents to beautify their teeth that may lead to changes in surface roughness. This study was designed to compare the silorane and methacrylate-based composites in bleached...

Introduction & Objective: Light curing and composite placement is effective on microleakage prevention. The aim of the present study was to compare the effect of two incremental com-posite placement and two light curing methods on microleakage of composite class one resto-rations. Materials & Methods: In this experimental study 60 maxillary premola...

Objectives It is difficult to achieve adhesion between resin cement and zirconia ceramics using routine surface preparation methods. The aim of this study was to evaluate the effects of CO2 and Er:YAG laser treatment on the bond strength of resin cement to zirconia ceramics. Materials and Methods In this in-vitro study 45 zirconia disks (6 mm in d...

Since it is not possible to form an adequate micromechanical bond between resin cement and zirconia ceramics using common surface treatment techniques, laser pretreatment has been suggested for zirconia ceramic surfaces. The aim of this study was to evaluate the effect of Carbon Dioxide (CO2) Laser treatment on shear bond strength (SBS) of resin ce...

Recurrent caries was partly ascribed to lack of antibacterial properties in composite resin. Silver and zinc nanoparticles are considered to be broad-spectrum antibacterial agents. The aim of the present study was to evaluate the antibacterial properties of composite resins containing 1% silver and zinc-oxide nanoparticles on Streptococcus mutans a...

Aim: This study evaluated the effect of 10% ascorbic acid on the bond strength between fiber post and composite resin core after applying 24% hydrogen peroxide. Materials and Methods: Twenty-four hydrogen peroxide-treated fiber posts were divided into 4 groups (n = 6). Group 1 was the control group with no treatment. In groups 2-4, post surfaces we...

Volume 21, Issue 1 (Scientific Journal of Hamadan University of Medical Sciences-Spring 2014) Avicenna J Clin Med 2014, 21(1): 1-7 | Back to browse issues page XML Persian Abstract Print Download citation: BibTeX | RIS | EndNote | Medlars | ProCite | Reference Manager | RefWorks Send citation to: Mendeley Zotero RefWorks Saharkhizan M, Fekrazad R...

Objective: The aim of this study was to evaluate the effect of cyclic loading on the bond strength of quartz fiber posts to root canal dentin after different surface treatments of different regions of root canal dentin. Materials and Methods: Forty-eight single-rooted human teeth were selected. Post spaces were prepared and then the teeth were div...

Mouth rinses beside the other methods have an important role in reducing dental caries. The aim of this study was in-vitro comparison of the anti-caries effect of polyphenol extract of green tea with 0.05% fluoride, 0.2% cholorhexidine and fluoridecholorhexidine. In this laboratory experimental study, 50 maxillary premolars were placed separately i...

The aim of this study was to determine the effect of epigallocatechin gallate (EGCG) on the shear bond strength of composite resin to bleached enamel. Ninety enamel surfaces of maxillary incisors were randomly divided into 9 groups as follows: G1: control (no bleaching); G2: bleaching; G3: bleaching and storage for seven days; G4 - 6: bleaching and...

Aim: The aim was to evaluate the antibacterial properties of composite resin containing nanosilver against Streptococcus mutans (SM) and Lactobacillus (L). Materials and methods: Nanosilver was added to Z250 composite at 0.5 and 1% by weight. In order to confirm the homogenous distribution of the nanoparticles in the composite resin, SEM-EDX ana...

Attempts to improve bond strength of self-etch adhesives can enhance the durability of composite restorations. The aim of the present study was to evaluate the effect of collagen and smear layer removal with sodium hypochlorite solution (NaOCl) and EDTA on micro-tensile bond strength (μTBS) of self-etch adhesives to dentin. It was an in-vitro study...

Objective: Dental caries is one of the most common infectious diseases worldwide. Saliva has many functions in the oral cavity and is the first line defense against dental caries. Oxidative stress can affect initiation and progression of many inflammatory and infectious diseases such as dental caries. Thus the aim of this study was to evaluate the...

Fiber reinforced composite (FRC) posts are cemented with resin cements. It is reported that using resin cements in canals sealed with eugenol-containing sealers reduces the post retention. However, there is controversy on the subject. The aim was to investigate the influence of eugenol-containing sealers and the amount of dentin removal from root c...

Incorporation of silver nanoparticles into composite resins is recommended for their reported antibacterial properties, but this incorporation can affect the wettability of such materials. Therefore, this study evaluated the effect of nano-silver addition to silorane-based and methacrylate-based composites on their contact angle. Nano-silver partic...

Addition of silver nanoparticles reduces the wettability of methacrylate and silorane-based composites Abstract: Incorporation of silver nanoparticles into composite resins is recommended for their reported antibacterial properties, but this in-corporation can affect the wettability of such materials. Therefore, this study evaluated the effect of n...

Introduction: There is decreased bond strength of composite resin to bleached enamel. Application of some anti-oxidants reduces the effect of bleaching agents and improves the bond strength of composite resin to enamel. The aim of the present study was to evaluate the effect of epigallocatechin gallat (EGCG) on the shear bond strength of composite...

Objective: The aim of this in vitro study was to evaluate the effect of the type of solvent in silane solution on microtensile bond strength of fiber posts to composite resin cores af-ter application of 24% hydrogen peroxide. Materials and Methods: Eighteen white fiber posts, immersed in 24% hydrogen peroxide were divided into three groups (n=6). I...

The aim was to evaluate the influence of water storage on fiber post-resin composite adhesion after different postsurface treatments. Forty-two fiber posts were used. Half of them were treated by hydrogen-peroxide and the other half were sandblasted. The adhesive (Single Bond, 3M, USA) was applied on the post. Core was built-up using flowable compo...

The aim of this in vitro study was to assess the microtensile bond strength of quartz fiber posts to different composites, and to composite combinations used as core materials. Thirty fiber posts were treated with a 24% hydrogen peroxide solution and silanized. The posts were divided into 5 groups according to the resin composite used as follows (n...

The aim of this in vitro study was to assess the microten-sile bond strength of quartz fiber posts to different composites, and to composite combinations used as core materials. Thirty fiber posts were treated with a 24% hydrogen peroxide solution and silanized. The posts were divided into 5 groups according to the resin composite used as fol-lows...

Composite restorations frequently have gingival margins apical to the cemento-enamel junction (CEJ). Microleakage at the cementodentinal margins is one of the most important causes of failure in these restorations. The current study evaluated microleakage at the occlusal and gingival margins of Class II packable composite restorations using resin-m...

Statement of the Problems: Assessment of tooth caries rate, especially in high-risk portion of the society, is important in order to plan appropriate preventive protocols. Purpose: The aim of the present study was to determine dental caries prevalence in 13-19-year-old Iranian students using two different caries indicators, including DMFT and SiC i...

Statement of the problem: When Root perforation occur in the middle third of the root, considerable canal length that would normally be available for post placement must be filled by the repair material, thus necessitating a considerably shorter post and leads to poorer retention. Purpose: the aim of the study was to comparison of retention of Tita...

This study evaluated the effect of surface polishing on mercury release from dental amalgam after treatment with 16% carbamide peroxide gel. Ninety-six samples from two different amalgam brands were prepared in truncated cone-shaped PVC polymer molds with an external surface area of 195 mm(2). Half of the specimens were polished with green and red...

The aim of this study was to investigate the effect of 16 percent carbamide peroxide gel on mercury and silver ions released from admixed and spherical dental amalgams. A total of 96 amalgam discs were prepared from two different types and brands of dental amalgam (admixed and spherical). The samples were stored at room temperature in glass tubes c...

Exposure to mercury can occur in occupational and environmental settings. During clinical work with dental amalgam, the dental personnel are exposed to both metallic mercury and mercury vapor. The aim of the present study was to investigate blood mercury level (BML) and its determinants among dentists practicing in Hamadan city, Iran. This cross se...

Objective: Bleaching of the teeth is considered as a safe, effective, and conservative pro-cedure to treat discolored teeth. The aim of the present study was to compare the amount of mercury and silver released from amalgam after applying two brands of carbamide pe-roxide 16% bleaching gel. Materials and Methods: For this experimental study, 384 am...

Objective: The purpose of the study was to evaluate the influence of adding nanofiller particles to a dentin-bonding agent on bond strength. Materials and Methods: Fifty-four human intact premolar teeth were divided in to 6 groups of nine. The teeth were ground on occlusal surfaces and were polished with a 320 and 600 grit silicon carbide papers, r...

The aim of this study was to investigate the benefits of incorporation of poly(methyl methacrylate)-grafted-nanoclay on the bond strength of an experimental one-bottle dentin bonding system. The effect of the modification on the stability of the nanoparticle dispersion in the dilute adhesive was also studied. Poly(methyl methacrylate) was grafted o...

Objective: There is no definitive data on the strength of glass fiber and cast posts with different length. This in vitro study was designed to investigate and compare the effect of length on the retentive strength of glass fiber and cast posts. Materials and Methods: Sixty recently extracted intact maxillary canine teeth were cut 1 mm above the CE...

Objective: Optimal dentin bonding is not always obtained in clinical practice due to func-tional forces. These forces may provide stresses throughout the tooth and restorative sys-tem, which in turn may affect the adhesive bond. This experimental study evaluated the effect of load cycling on bond strength of self-etch systems. Materials and Methods...