Mohannad Nassar

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• BDS, MSc., PhD
• Professor (Associate) at University of Sharjah

Inositol hexaphosphate (IP6) is the most abundant inositol phosphate in nature and an essential molecule for different biological functions. IP6 has a unique structure granting it distinctive properties; a high negative charge density provides IP6 with an immense chelating ability and valuable antioxidant properties. IP6 is also simple and cost-eff...

We evaluated the effect of phytic acid on matrix metalloproteinase (MMP)‐ or cysteine cathepsin (CC)‐mediated dentin degradation. Demineralized dentin beams were divided into five groups (n = 12) and treated with 1%, 2%, or 3% phytic acid or with 37% phosphoric acid. Untreated demineralized beams served as controls. After incubation for 1 or 3 wk,...

Objectives: To investigate the effect of phytic acid, inositol hexaphosphate (IP6), used as a final rinse on the surface of instrumented root canals and evaluate its effect on the viability, alkaline phosphatase activity (ALP) and morphology of osteoblastic-like cells. Moreover, we assessed IP6 effect on resin adhesion to NaOCl-treated dentin and t...

This study aimed to evaluate the effect of phytic acid (IP6), used as etchant, on resin-dentin bond strength, smear layer removal, and the viability of pulpal cells. Flat dentin surfaces with smear layer were etched with 1% IP6 for 60, 30, or 15 s; in the control group 37% phosphoric acid (PA) was used. Dentin surfaces were rinsed, blot-dried, and...

Introduction Elevated glucose can have a detrimental effect on the function and healing process of periodontal cells in inflammatory conditions. Hesperidin (HPN), a bioflavonoid found abundantly in citrus fruits, has numerous biological benefits, including regenerative and anti-inflammatory properties. The current in-vitro study aimed to assess the...

Aim To evaluate the current status of endodontic education and assessment at an undergraduate/predoctoral level in dental schools worldwide. Methodology The current survey comprised a 50‐item online questionnaire related to undergraduate endodontic education. The project leaders emailed the survey's details to faculty members responsible for endod...

This study investigated phytic acid (IP6) effect on chemical, structural, and mechanical characteristics of nickel–titanium (NiTi) files. The tested files were equally divided into groups according to the immersion protocol: sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA), IP6, EDTA followed by NaOCl, and IP6 followed by NaOCl....

Objectives To assess the impact of various organic and inorganic acids on the roughness, demineralization, and collagen secondary structures of human dentin and to compare these effects with those of traditional agents, specifically phosphoric acid (PA) and ethylenediaminetetraacetic acid (EDTA). Methods Coronal dentin discs (n = 10) were examined...

We assessed the effect of non-protein thiols (NPSH), reduced glutathione (GSH) and n-acetylcysteine (NAC), on resin shear bond strength (SBS) to hydrogen peroxide (H2O2)-treated dentin, and their effects on the characteristics of dentin in comparison to ascorbic acid (AA) and sodium thiosulfate (STS). H2O2-treated dentin was conditioned with 5% AA,...

Objectives Creating environmentally sustainable healthcare culture within the dental field requires embedding the content in the dental curriculum at the undergraduate level. This study aimed to explore the current awareness and drivers among dental students and educators regarding environmentally sustainable dentistry (ESD) in the United Arab Emir...

Objectives This study evaluated phytic acid (IP6) effect on the viability, alkaline phosphatase (ALP) activity and calcium release of human periodontal ligament (HPDL) cells in optimal (OGL) and elevated glucose level (EGL) in cell culture media. Materials and methods Cells were seeded in OGL (1000mg/L) or EGL (4500 mg/L) media. IP6 was added at 0...

Creating environmentally sustainable oral healthcare culture requires embedding contents in dental curriculum. This study aimed to explore the current knowledge and drivers among dental students and educators regarding environmentally sustainable dentistry (ESD) in the United Arab Emirates (UAE) and identify barriers and enablers to embrace it. A c...

Objective: The goal of this study was to compare the pulp temperature increase during light curing of different composite thicknesses in deep class I cavities using two thermal sensing tools. Methodology: Round occlusal class I cavities with a remaining dentin thickness (RDT) of 1 mm from the cavity floor were performed on 15 extracted sound mol...

In-office bleaching with high concentrations of hydrogen peroxide (H2O2) agents causes undesirable alterations in the enamel. Surface pre-reacted glass-ionomer (S-PRG) filler is a functional material known for its acid-neutralizing and demineralization-inhibition properties. This study evaluates the effect of S-PRG filler incorporation in H2O2-base...

This study investigated retreatment of oval canals filled with gutta-percha and different sealers using WaveOne Gold (WOG). Single oval canals were prepared to size 30, 0.04 and obturated with gutta percha and AH Plus (AHP) or TotalFill bioceramic (TFBC) sealer. After 6-month incubation, the canals were retreated with WOG Primary (25, 0.07) under s...

Root canal infections are associated with biofilms and are treated with chemical irrigants with a high success rate. However, treatment failure does arise, which is attributed primarily to resistance exhibited by biofilms. Currently used irrigants in root canal treatment have disadvantages, and there is therefore a need for more biocompatible alter...

Objectives: Surface reaction-type pre-reacted glass-ionomer (S-PRG) filler releases six types of ions with a neutralizing ability. This study evaluated the effect of S-PRG filler incorporation in an H2O2-based bleaching material on the bleaching efficacy, pH, and reaction state. Materials and methods: The experimental bleaching material was formul...

The objective of this study was to compare the physical and optical stability of resin composite materials with different filler characteristics. Ninety-six resin composite blocks (6 mm × 6 mm × 2 mm) were prepared using four different types of resin composite, divided into four groups. Specimens from the same material were randomly divided into fo...

We evaluated the shear bond strength (SBS) of mineral trioxide aggregate (MTA) and Biodentine (BD) to coronal dentin after treatment with ethylenediaminetetraacetic acid (EDTA), phytic acid (IP6), or etidronic acid (HEDP). Sodium hypochlorite-treated dentin surfaces were randomly divided into four groups according to conditioning protocol namely, 1...

Objectives: The United Arab Emirates (UAE) is one of the top 5 countries in the world in terms of juice consumption per capita. The rising consumption of beverages is a major contributor to a plethora of diseases, including heightened risks of developing obesity, diabetes, and osteoporosis. Beverages with low pH also tend to magnify the risk of lon...

Dental clinicians are at increased risk for developing tinnitus due to exposure to high levels of occupational noise. This study aimed to determine tinnitus prevalence and associated factors among dental clinicians. Interviews were conducted with 150 randomly selected dental clinicians using a questionnaire. Noise levels were measured at three poin...

Objectives: Surface reaction-type pre-reacted glass-ionomer (S-PRG) filler releases six types of ions with a neutralizing ability. This study evaluated the effect of S-PRG filler incorporation in an H2O2-based bleaching material on the bleaching efficacy, pH, and reaction state. Materials and Methods: The experimental bleaching material was formula...

Objectives To study phytic acid (IP6) effect on collagen solubilization by assessing hydroxyproline (HYP) release, evaluate its binding to demineralized (DD) and mineralized dentin (MD) and determine the effect of different media on debinding of IP6. Methods Demineralized dentin beams were incubated in 1%, 2% or 3% IP6 and HYP release was evaluate...

Objective The interest in bioceramic materials has been steadily growing for different applications in endodontics. With the continued introduction of new bioceramic-based materials into the market, it is of great importance to assess the biocompatibility before providing recommendations on their clinical use. This study evaluated the in vitro cyto...

Objective To evaluate the educational value of YouTube as a learning tool for dental students regarding endodontic access cavity preparation. Methods and findings YouTube search was made for videos related to endodontic access cavity preparation using specific terms. After exclusions, 41 videos were chosen and assessed for tooth type, video length...

Objectives Single-shade composite systems are gaining popularity among clinicians due to the claimed potential of blending with different tooth structure shades while restoring the tooth. The purpose of this study was to evaluate the blending effect of two single-shade composite with different shades of conventional resin composite systems. Materia...

This study assesses the retreatability of TotalFill bioceramic (TFBC) and AH Plus (AHP) sealers and their impact on retreatment force and torque. Twenty-six premolar teeth with single oval canals were instrumented, obturated using the matched gutta-percha cone technique with one of the tested sealers, and then temporized. After a 6-month incubation...

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 (μTBS) of resin-based cement to enamel and dentin using manufacturer-provided etchants, phosphoric acid (PA) for enamel and a mixture of 10% citric acid and 3% ferric chloride (CAF) for...

The aim of this study was to evaluate the content of periradicular surgery-related YouTube videos available for patients’ education. YouTube search was made for videos related to periradicular surgery using specific terms. After exclusions, 42 videos were selected, viewed and assessed by two independent observers. The videos were assessed in terms...

Background Phytic acid (IP6) is a promising and emerging agent, and because of its unique structure and distinctive properties, it lends itself to several applications in dentistry. Recently, IP6 was proposed as a potential chelating agent in endodontics. However, there is limited knowledge regarding its antimicrobial and antibiofilm effectiveness....

The aims of this study were to evaluate the effect of cranberry juice (CB) on demineralized dentin collagen by evaluating the mechanical properties of the collagen and compare its efficacy to glutaraldehyde (GA). The effect of 100%, 50%, 25% pure CB, and 0.5% GA were tested in this experiment. The water absorption of collagen was evaluated by swell...

Objectives To evaluate the status of teaching of repair of defective resin-based composite restorations in dental schools in the Middle Eastern and North African (MENA) countries. Methods A validated 14-item questionnaire was mailed to the directors of the operative/restorative dentistry department in 40 MENA dental schools. Data were collected on...

Objectives To assess the effect of additional apical enlargement using nickel titanium (NiTi) instruments on the incidence of microcracks using micro-computed tomographic analysis. Materials and methods Fifty-one premolars with single canals were enlarged to ProTaper Gold (PTG) F2 (25/08) (Dentsply Sirona), ProFile Vortex Blue (VB) 25/06 (Dentsply...

Introduction Due to its ability to arrest untreated dental caries, silver diamine fluoride (SDF) has been advocated for indirect pulp capping procedures. However, the high concentrations of silver and fluoride in SDF raise concerns about its biocompatibility to pulpal tissues. Objectives This study aimed to investigate the effect of SDF on the viab...

The effects of surface pre‐reacted glass‐ionomer (S‐PRG) filler on pulpal cells and on the composition of dentinal deposits were investigated. Proliferation (CCK‐8), cytotoxicity (LDH), and differentiation activity (ALP) tests, along with cell morphology observations, were conducted at 6 and 24 h after treatment of pulpal cells with different S‐PRG...

Bacterial biofilms are microbial lifestyles found in all environments. Up to 80% of human infections and 60–70% of hospital-acquired infections have a biofilm origin, with Staphylococcus aureus one of the leading causes of these infections. Microorganisms in biofilms exhibit significant antimicrobial resistance which poses important treatment chall...

Objectives Despite the agreement that there is no longer any indication for arsenic use in modern endodontics, some concerns are surfacing about the minute amount of arsenic trioxide (As2O3) released from Portland cement-based materials. The present study investigated the effect of different concentrations of As2O3 on rat pulpal cells and the effic...

Objective: Despite the controversial results regarding the amount of arsenic (As) in mineral trioxide aggregate (MTA) and MTA-like cements, it is prudent to assess the effect of this heavy metal on pulpal cells and search for methods to attenuate its toxicity. This study investigated the toxic effect of As on pulpal-like cells and evaluated the inf...

Objectives: Phytic acid (IP6), a naturally occurring agent, has been previously reported as a potential alternative to ethylenediaminetetraacetic acid (EDTA). However, its effect on adhesion to sodium hypochlorite (NaOCl)-treated dentin and its interactions with NaOCl have not been previously reported. Thus, in this study, the effects of IP6 on res...

Purpose To evaluate the effect of phytic acid (IP6) on the surface roughness and microhardness of human root canal dentin and compare it to other smear layer removal agents. Materials and methods Fifty extracted human maxillary incisors were sectioned longitudinally into a total of 100 specimens followed by embedding in auto-polymerizing acrylic r...

Root caries is one of the most significant dental problems among older adults. In order to prevent tooth loss due to root caries, the risk factors must be identified. The objectives of the study were to evaluate the prevalence of root caries and the associated risk factors among patients attending Ras Al-Khaimah College of Dental Sciences (RAKCODS)...

Aim: To determine the genetic makeup of methicillin-sensitive/methicillin-resistant Staphylococcus aureus (MSSA/MRSA) from nasal colonization and environmental contamination in dental clinics. Materials and Methods: Nasal swabs from students and health care workers and environmental swabs were obtained at two academic dental clinics in the United...

Root caries is one of the most significant dental problems among older adults. In order to prevent tooth loss due to root caries, the risk factors must be identified. The objectives of the study were to evaluate the prevalence of root caries and the associated risk factors among patients attending Ras Al-Khaimah College of Dental Sciences (RAKCODS)...

Purpose: Phytic acid (IP6) works well as an etchant in dentin bonding to remove the smear layer due to its acidity and chelating effect. This study compared the etching effect of IP6 with phosphoric acid (PA) and ethylenediaminetetraacetic acid (EDTA) on resin-dentin bond strength, micromorphology of the etched dentin surface and nanoleakage forma...

Poster Presentation at the 1st Gulf Congress of Clinical Microbiology and Infectious Diseases (GCCMID) (Dubai UAE, 4th -7th May 2016): Antimicrobial effect of naturally occurring agent on Enterococcus faecalis

Objectives: One of the properties of an ideal root canal irrigant is the ability to eradicate Enterococcus faecalis which is one of the most resistant microorganisms encountered in persistent peri-radicular lesions. The aim of this study was to test the in vitro antibacterial effectiveness of a naturally occurring agent called phytic acid (IP6) aga...

Objective: This study examined the effect of phytic acid (IP6) in stabilizing the morphology of dentine collagen network and resin-dentine bonding. Methods: Dentine beams were fully demineralized with 10% phosphoric acid (PA) or 1% IP6 (pH 1.2). PA-demineralized beams were divided into three groups: (a) no further treatment (control), (b) treatm...

Aim: To determine the root surface strain (RSS) generated during root canal shaping and its effects on apical microcrack development. Methodology: Twenty-five extracted human mandibular premolars were selected and decoronated. The teeth were instrumented with either the ProTaper (PT) or WaveOne (WO) (Dentsply Maillefer) NiTi rotary systems (n =...

Objective Collagen degradation at the resin–dentin interface deteriorates dentin bond durability. The use of natural cross-linkers might offer a positive approach to stabilize the resin–dentin interface. This study evaluated the effects of incorporation of natural cross-linkers into a self-etch adhesive primer on the immediate and long-term micro-t...

Objective: The purpose of this study was to measure strain generated during root canal shaping and its effect on apical microcrack development. Method: 25 mandibular premolars were selected and decoronated. Roots were distributed into 2 groups of 10 teeth according to the NiTi rotary systems used (ProTaper (PT) and WaveOne (WO), Dentsply Maillefe...

Background/purpose Saliva plays a critical role in the oral cavity health; the levels of its constituents alter with age. The reduced glutathione:oxidized glutathione ratio (GSH:GSSG) in the plasma is reported to be lower in elderly people and thus can be an indicator of age. The aim of this study was to detect age-related changes in salivary bioma...

Phosphoric acid (PA) etching used in etch-and-rinse adhesives is known to activate host-derived dentinal matrix-metalloproteinases (MMPs) and increase dentinal permeability. These two phenomena will result, respectively; in degradation of dentin-adhesive bond and leaching of some monomers especially 2-hydroxyethyl methacrylate (HEMA) into the pulp...

To evaluate the influence of reduced glutathione (GSH) application on 2-hydroxyethylmethacrylate (HEMA) cytotoxicity on rat pulpal cells, and evaluated the effect of etched-dentine treatment with GSH on the immediate microtensile bond strength (μTBS) of etch-and-rinse adhesive. The cytotoxicity of 10 mM HEMA, 10 mM HEMA+1 mM GSH, 10 mM HEMA+5 mM GS...

Objective: This study aimed to evaluate the influence of reduced glutathione (GSH) application on HEMA cytotoxicity on rat pulpal cells, and the effect of etched-dentin treatment with GSH on the immediate microtensile bond strength (µTBS) of etch-and-rinse adhesive. Method: The cytotoxicity of HEMA (10 mM), GSH (10 mM) or GSH with HEMA (10 mM eac...

Objective: A novel Mussel-mimetic adhesive resin was synthesized from plant-derived sources as 3,4-dihydroxycinnamic acid (caffeic acid; DHCA) and 4-hydroxycinnamic acid (p-coumaric acid; 4HCA) to synthesize poly-(DHCA-co-4HCA) by transesterification technique (Kakeno et al., Polymer Journal, 2011). It has been reported to have a strong adhesive ch...

Objectives: The aim of this in vitro study was to investigate the effect of incorporation of natural cross-linkers into the primer of a self-etching adhesive on resin-dentine bond strength. Methods: Flat dentine surfaces were prepared from extracted human molar teeth and were applied with the following self-etching primers. The 0.5% hesperidin (...

The aims of this study were to investigate the effects of hesperidin, a citrus flavonoid, on human root dentin demineralization and collagen preservation, and compare it with chlorhexidine and grape seed extract. Specimens were assigned to different treatment groups: hesperidin, chlorhexidine and grape seed extract. Specimens were subjected to pH c...

This in vitro study assessed the adhesion of Epiphany self-etch (SE) root canal sealer to dentin treated with different irrigation regimens. Flat dentin surfaces were obtained from human third molar teeth; smear layer was created on each sample. Five groups of 10 samples each were conditioned with one of the following regimens: (1) deionized water...