Mohammad Kharazifard - Academia.edu (original) (raw)

Papers by Mohammad Kharazifard

1 Assosiated Professor, Dental Research Center, Dentistry Research Institute, Department of Resto... more 1 Assosiated Professor, Dental Research Center, Dentistry Research Institute, Department of Restorative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran 2 Professor, Dental Research Center, Dentistry Research Institute, Department of Restorative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran 3 Research Member, Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran 4 Dentist, Private Office, Ahvaz, Iran

Frontiers in Dentistry, 2019

Objectives: This study aimed to compare the transportation of the mesiobuccal canal of maxillary ... more Objectives: This study aimed to compare the transportation of the mesiobuccal canal of maxillary molars following root canal preparation with HyFlex CM (HCM) and Edge Taper Platinum (ETP) rotary systems and stainless steel (SS) hand files using cone-beam computed tomography (CBCT). Materials and Methods: This in-vitro study was performed on 48 maxillary molars in three groups of 16. The teeth were mounted in acrylic blocks, and root canals were prepared using HCM in group 1 (up to #30/0.06), ETP in group 2 (up to F3/0.06), and SS hand files in group 3 (up to #30). CBCT scans were taken before and after root canal preparation. The amount of canal transportation was measured at 0, 3, 6, and 9mm from the apex. Data were analyzed using Kruskal-Wallis and Mann-Whitney tests. Results: The difference in canal transportation at 0 and 6mm from the apex was significant between the HCM and ETP groups (P=0.031 and 0.023) but none of the systems showed any significant difference with hand files ...

Lasers in Medical Science, 2019

During the injection of local anesthesia in pediatric dental procedures, from the injection time ... more During the injection of local anesthesia in pediatric dental procedures, from the injection time until the elimination of tissue anesthesia, inevitable problems were reported. According to the encouraging results of previous studies addressing the positive effects of laser therapy on increasing the microcirculation, we aimed to investigate the clinical effect of photobiomodulation therapy on the reversal of soft tissue anesthesia in children. Using a split-mouth design, 34 children aged 4 to 8 years old, candidate for receiving local infiltration injection at both right and left side in mandible, were enrolled in the study. The mandibular right and left quadrants were randomly assigned to groups of laser or sham laser: in laser side, patients received 810-nm laser irradiation, and in the sham laser group, the patients had the laser in off mode at 45 min after injection with an interval of 7-10 days between two sessions of each quadrant treatments. The degree of anesthesia was evaluated using the palpation technique alternately every 15 min. Data were analyzed using paired sample t test and multiple linear regression test. The mean duration of anesthesia expressed in minutes was equal to 145.15 ± 23.27 and 188.82 ± 12.31 for the laser group and sham laser group, respectively. There was a significant difference in duration of anesthesia between two groups (P < 0.001). Considering the results and limitations of the present study, photobiomodulation therapy by 810-nm diode laser can be proposed as a non-invasive method in order to reduce the duration of anesthesia in pediatric patients.

Acta Odontologica Scandinavica, 2014

Along with their re-mineralizing capacity, calcium phosphopeptide-amorphous calcium phosphate pro... more Along with their re-mineralizing capacity, calcium phosphopeptide-amorphous calcium phosphate products combined with fluoride (CPP-ACPF) could also be beneficial by neutralizing acidic salivary and plaque pH. The purpose was to evaluate the effect of CPP-ACPF on salivary and plaque pH in orthodontic patients. As a triple-blind, cross-over randomized trial, 30 orthodontic patients with fixed appliances (age range = 15.70 ± 4.08 years) were recruited and randomly assigned to two groups. A CPP-ACPF paste (MI Paste Plus, GC America, Alsip, IL) was used by group 1 (n = 15) and a placebo by group 2 (n = 15) for 1 month. After a 1 month washout period, patients used the alternative paste for another month. Plaque and salivary pH levels were measured at all before and after periods. By applying MI Paste Plus, the plaque pH increased from 5.81 ± 0.45 to 6.60 ± 0.38 (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05), whereas the before and after salivary pH recordings, which were 6.72 ± 0.43 and 6.71 ± 0.38, respectively, remained statistically unchanged (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.05). MI Paste Plus can be clinically beneficial in increasing plaque pH levels, but has no effect on the salivary pH.

Indian Journal of Pathology and Microbiology, 2014

p16INK4a is a tumor suppressor gene playing a critical role. Researches have indicated the gene t... more p16INK4a is a tumor suppressor gene playing a critical role. Researches have indicated the gene to be altered in oral squamous cell carcinoma. Present studies have tried to assess the correlation between p16INK4a expression and INK4a locus mutation in relation to grades and stages of this tumor. Expression of p16INK4a was studied immunohistochemically in 58 oral squamous sell carcinoma samples and INK4a locus mutation was determined by polymerase chain reaction (PCR) and conformation sensitive gel electrophoresis (CSGE). Expression of p16INK4a was higher in stage1 compared to stage 2, 3, and 4 (P = 0.234). The difference was not significant in grade 1, 2, and 3 (P = 0.671). The average values of total score (TS) were significantly higher in stage1 compared to stage 2, 3, and 4 (P = 0.035). The average values of complete score (CS) were higher in stage 1 compared to stage 2, 3, and 4 (P = 0.061). The research did not show a significant correlation between lymph node involvement and p16INK4a expression (P = 0.491). It seems that 5.1% (3/58) of samples have mutation in INK4a locus. Loss of p16INK4a expression occurred in initial stages of oral squamous cell carcinoma. Evaluation of TS and CS for p16INK4a might be a useful clinical indicator concerning the tumor. However, gene mutation is believed to have minor rate of genetic alteration in carcinogenesis.

Acta Cirurgica Brasileira, 2009

PURPOSE: To evaluate retinal manifestations of Schistosomiasis mansoni in its hepatosplenic form ... more PURPOSE: To evaluate retinal manifestations of Schistosomiasis mansoni in its hepatosplenic form in mice. METHODS: It was performed a study with two groups of mice; one of them was infected with 40 cercariae of Schistosoma mansoni. After 120 days of the infection, the eyes underwent a retinal microscopy study. The histology findings were reported. Histomorphometric analysis was also performed, including: thickness measurement of the retinal layer and the number of the ganglion layer cells. RESULTS: In one case a retinal granuloma was found. The analysis of the other histological sections demonstrated normal architecture of the retina. The mean thickness of the retinal layer between the two groups were similar (41.81±6.09µm versus 38.48±8.58µm - p=0.279); as well as the mean number of the ganglion layer cells (20.93±4.88 versus 20.64±4.10 - p=0.864). Disorganization of the retinal layers was not identified and the histomorphometric analysis revealed no significant difference between ...

Frontiers in Dentistry, 2021

Objectives: This study evaluated the effect of two educational interventions on knowledge and sel... more Objectives: This study evaluated the effect of two educational interventions on knowledge and self-reported practice of mothers of 8-year-old children regarding emergency management of traumatic dental injuries (TDIs). Materials and Methods: Six public elementary schools (girls and boys) in Tehran were randomly selected. The mothers of 8-year-old students at each school were randomly assigned to three groups: intervention by poster, intervention by pamphlet, and control. An anonymous valid and reliable questionnaire, including demographics, previous experience on TDIs, mothers’ knowledge, and self-reported practice about emergency management of TDIs was provided to the mothers. After collecting the questionnaires, educational interventions by poster and pamphlet with similar contents regarding step-by-step emergency management of TDIs were performed for the target groups. Three months after the interventions, the same questionnaire was completed by the mothers. The results of pre-te...

International Journal of Dentistry, 2022

Objectives. This study aimed to assess the effect of implant angulation on the rotational displac... more Objectives. This study aimed to assess the effect of implant angulation on the rotational displacement of a 3-unit bridge following a digital impression. Materials and Methods. This in vitro experimental study evaluated 3 master models of the maxilla with Kennedy’s class III partial edentulism and bilateral three-unit implant-supported fixed partial dentures. Two implants were placed with 0° (first model), 15° (second model), and 30° (third model) interimplant angles. The implants were placed bilaterally at the sites of first premolars and first molars from the posterior towards the anterior region and coded A (posterior) and B (anterior) in the left, and C (posterior) and D (anterior) in the right side. Next, their position was recorded using a coordinate measuring machine to serve as a reference. The models were then scanned by both 3Shape and Sirona digital scanners (12 times by each scanner). The obtained data were compared with the reference data three-dimensionally using GOM I...

Journal of Dentistry (Tehran, Iran), 2017

Multilevel analysis which was primarily introduced to deal with hierarchical data was later appli... more Multilevel analysis which was primarily introduced to deal with hierarchical data was later applied extensively for research in other fields of science and not only for nested data, but also for repeated measurements or clustered trials. This method of statistical analysis was applied in dental studies in the 1991 for the first time but despite its value for data analysis in dental studies, its application for dental studies remains limited until now. This manuscript reviews the applications of this method in dental studies.

$Research paper thumbnail of Prevalence of maxillofacial fractures in hospital patients: A five year retrospective study$

1. Department of Oral and Maxillofacial Surgery, Alborz University of Medical Sciences, Karaj, Ir... more 1. Department of Oral and Maxillofacial Surgery, Alborz University of Medical Sciences, Karaj, Iran 2. Dental Clinical Research Development Unit, Alborz University of Medical Sciences, Karaj, Iran 3. Department of neurosurgery, Shahid madni hospital, Alborz University of Medical Sciences, karaj, Iran 4. Department of Epidemiology and Biostatistics, Dental School, Tehran University of Medical Sciences, Tehran, Iran 5 Department of Surgery, Shahid Madni hospital, Alborz University of Medical Sciences, karaj, Iran 6. Student Research Committee, Alborz University of Medical Sciences, Karaj, Iran

Associate Professor, Department of Community Oral Health, School of Dentistry, Tehran University ... more Associate Professor, Department of Community Oral Health, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Professor, Department of Oral and Maxillofacial Medicine, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Research Member of Dental Research Center Tehran University of Medical Sciences, Tehran, Iran Undergraduate Student, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran PhD Candidate, Department of Community Oral Health, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran

Journal of Dentistry, 2021

Statement of the Problem: Adequate compressive strength is an important characteristic for an ide... more Statement of the Problem: Adequate compressive strength is an important characteristic for an ideal liner. Purpose: This study aimed to assess the compressive strength of several commonly used liners. Materials and Method: This in vitro, experimental study evaluated 120 samples fabricated of Dycal, Calcimol LC, Vitrebond, Activa Bioactive, and TheraCal LC (n=24) liners according to the manufacturers’ instructions. The samples were fabricated using a cylindrical stainless steel mold with 6±0.1 mm height and 4±0.1 mm internal diameter. Half of the samples in each group (n=12) underwent compressive strength test immediately after completion of their primary setting while the other half (n=12) underwent compressive strength test after 24 h. During this period, the samples were immersed in deionized water (grade 3) and incubated at 37±1°C and 100% humidity for 24 h. The compressive strength was measured using a universal testing machine. Data were analyzed using two-way ANOVA followed by...

Journal of Dentistry (Tehran, Iran), 2016

Objectives: The purpose of this study was to develop and test a new tool for radiographic densito... more Objectives: The purpose of this study was to develop and test a new tool for radiographic densitometry by combining periapical films and aluminum step wedge. Materials and Methods: We reviewed 50 Kodak E-speed intraoral films. An aluminum step wedge consisting of 16 steps was constructed. Each step was 1mm×3m×10mm. The step wedge was exposed to varying exposure times, ranging from 0.05 second to 0.5 second, increasing in 0.05 second increments. Films were digitalized after processing and the MATLAB software algorithm was ran subsequently. Density of the films was measured again using a digital densitometer. In order to compare the two imaging techniques, three steps were selected. Output data from the MATLAB algorithm were compared with data obtained from the digital densitometer. Results: The new method could detect significant differences between subsequent exposure times in step 7, while the densitometer did that in steps 7 and 12. The new method’s sensitivity in determining dens...

The Journal of Contemporary Dental Practice, 2020

Aim: This study aimed to assess the effect of addition of nano-titanium oxide (nano-TiO 2), nano-... more Aim: This study aimed to assess the effect of addition of nano-titanium oxide (nano-TiO 2), nano-silicon dioxide (nano-SiO 2), and a combination of both, on antimicrobial activity of an orthodontic composite. Materials and methods: Molds measuring 0.64 × 0.5 mm were used for the fabrication of composite disks. For this purpose, 0.5% and 1% nano-TiO 2 , nano-SiO 2 , and a combination of both (0.5% nano-TiO 2 and 0.5% nano-SiO 2), were mixed with Transbond XT composite (3M Unitek). A total of 180 composite disks were fabricated for eluted component, disk agar diffusion (DAD), and biofilm inhibition tests. The colony counts of Streptococcus mutans (S. mutans), Streptococcus sanguinis (S. sanguinis), and Lactobacillus acidophilus (L. acidophilus) and the diameters of growth inhibition zones were measured at 3, 15, and 30 days after exposure to the materials. Data were analyzed using one-way ANOVA and a post hoc test. Results: None of the nano-TiO 2 and nano-SiO 2 concentrations had any significant effect on the growth inhibition zone. All tested concentrations of nano-TiO 2 and nano-SiO 2 decreased the colony count of all bacteria. The composite sample containing both nano-TiO 2 and nano-SiO 2 had the greatest efficacy for reduction of S. mutans and S. sanguinis colony counts at all three time points. Also, 1% nano-TiO 2 and 1% nano-SiO 2 had similar effects on L. acidophilus in eluted component test. Conclusion: Addition of TiO 2 and SiO 2 nanoparticles conferred antimicrobial property to the tested orthodontic composite. Clinical significance: Using orthodontic composite containing nonoparticles with antibacterial activity may prevent dental caries.

Dental and Medical Problems, 2020

Background. The success of composite resin restorations depends to a great extent on their color ... more Background. The success of composite resin restorations depends to a great extent on their color stability. However, discoloration is still a problem in composite resin restorations. Objectives. The aim of the study was to evaluate the effect of different staining solutions on the color stability of composite resins. Material and methods. A total of 96 composite disks, 2 mm in height and 8 mm in diameter, were fabricated of 3 commercially available composite resins. The samples were divided into 4 groups of 8 and were immersed in 4 staining solutions: coffee, tea, soda, and artificial saliva. The color parameters of the samples were measured and recorded before as well as 2, 4 and 8 weeks after immersion by spectrophotometry, using the CIELAB color space. A color change (ΔE) ≤3.3 was considered the acceptable threshold for visual perception. The results were analyzed using the one-way analysis of variance (ANOVA) and Tukey's post hoc test (p < 0.05). Results. All the composite resins in the study showed discoloration in all the staining solutions. The ΔE of Vertise TM Flow was the highest in the tea solution. The lowest ΔE occurred in the Filtek TM Z250 composite in artificial saliva. Conclusions. This in vitro study showed that the color stability of tooth-colored restorations can be influenced by dietary habits.

LASER THERAPY, 2017

This study aimed to assess the microshear bond strength of a repairing self-adhesive flowable com... more This study aimed to assess the microshear bond strength of a repairing self-adhesive flowable composite to ceramic after mechanical, chemical and laser treatment of the ceramic surface. Materials and Methods: Forty zirconia and forty feldspathic ceramic blocks measuring 8 x 8 x 2 mm were fabricated. Feldspathic blocks were divided into four groups of control (1), laser (2780 nm) (2), sandblasting + hydrofluoric (HF) acid + silane (3) and laser (2780 nm) + HF acid + silane (4). Zirconia blocks were also divided into four groups of control (1), laser (2780 nm) (2), sandblasting + Z-Prime Plus (3) and laser (2780 nm) + Z-Prime Plus (4). Vertise Flow composite was bonded to treated ceramic surfaces as a repairing material, then the samples were subjected to 1000 thermal cycles. Repair bond strength was measured by Instron machine and data were analyzed using one-way ANOVA and post hoc test (P < 0.05). Results: Maximum and minimum bond strength values were observed in zirconia-control (22.57 ± 4.76 MPa) and feldspathic-control (8.65 ± 6.41 MPa) groups, respectively. There was no significant differences between subgroups within the zirconia or feldspathic groups (P > 0.05) , however the bond strength of zirconia subgroups was significantly higher than that of feldspathic subgroups. Conclusion: Vertise Flow provides relatively good bond strength to ceramic even with no surface treatment.

American Journal of Otolaryngology, 2019

Ankylosis of the temporomandibular joint (TMJ) is a disabling condition due to the fusion of join... more Ankylosis of the temporomandibular joint (TMJ) is a disabling condition due to the fusion of joint to the base of skull and results in mouth opening limitation. Several surgical techniques have been described for treatment of this condition but no consensus has been reached. This study sought to assess the success of treatment with regard to long-term functional improvement and rate of complications in ankylosis patients during a 10-year period. Materials and Methods: Patients who underwent unilateral or bilateral condylectomy without joint reconstruction during 2001-2011 in the Maxillofacial Surgery Department of Shariati Hospital were evaluated in this historical cohort study. The patients were recalled to ensure the accuracy of information in their medical records and were clinically examined. Improvement in their joint function and rate of complications were evaluated. Data were analyzed using Wilcoxon Signed rank test, multivariate tests, Mauchly's sphericity test and McNemar's test. Results: A total of 27 subjects (13 males and 14 females) with a mean age of 34.8 years and 6.1 years mean duration of follow-up were evaluated. The results of observation showed that trauma was the most common cause of ankylosis (63%). The most common type of ankyloses was fibrous (55.6%) and 55.6% of the patients had bilateral ankylosis. Maximum mouth opening (MMO), the amount of lateral movement and open bite significantly improved after the operation (P<0.001). Frontal, zygomatic and buccal nerves had been injured in 4, 4 and 3 patients, respectively during the operation. Conclusion: Condylectomy without reconstruction significantly improves the TMJ function in patients with TMJ ankylosis with regard to MMO, the amount of lateral movement, maintenance of occlusion and the skeletal form.

Journal of Islamic Dental Association of IRAN, 2016

Background and Aim: Restoration of primary anterior teeth with severe caries extending to the gin... more Background and Aim: Restoration of primary anterior teeth with severe caries extending to the gingival margin is challenging for many clinicians especially in uncooperative children. Resin modified glass ionomer cements (RMGICs) can be suitable for use in such cases since they require fewer application steps than composite resins. This study aimed to assess the fracture strength of severely damaged primary anterior teeth after their coronal build-up using RMGIC and composite resin. Materials and Methods: This in vitro, experimental study was conducted on 40 primary teeth that met our inclusion criteria. After decoronization, they were cleaned and root canals were filled. In the coronal cavity, one layer of base was applied and an undercut was created in the canal wall above the base. The teeth were divided into two groups of 20 for coronal restoration. In group 1, etching, bonding, intracanal post fabrication and restoration with composite resin were carried out. In group 2, conditioning, intracanal post fabrication and restoration with Fuji II LC RMGIC were performed. After thermal cycles, fracture strength of teeth was measured and compared in the two groups using t-test. Results: Fracture strength of teeth was not significantly different between two groups restored with composite resin (5.03±2.30 MPa) and RMGIC (5.67±2.38 MPa) (P>0.05) Conclusion: In the post and crown build up of severely damaged primary anterior teeth with severe caries extending to the gingival margin, Fuji II LC RMGIC can be used as an alternative to composite resin especially in uncooperative children or treatment under general anesthesia.

Iranian endodontic journal, 2016

It is essential for clinicians to have knowledge about root canal configuration, although its mor... more It is essential for clinicians to have knowledge about root canal configuration, although its morphology varies largely in different ethnicities and even in different individuals within the same ethnic group. The current study reviewed the root canal configuration of root canals in mandibular first and second premolars among Iranian population based on independent epidemiological studies. A comprehensive search was conducted on retrieved articles related to root canal configuration and prevalence of each types of root canal in mandibular premolars based on Vertucci's classification. An electronic search was conducted in Medline, Scopus and Google Scholar from January 1984 to September 2015. In eleven studies conducted in eight provinces, 1644 mandibular first premolars and 1268 second premolars were investigated. Within mandibular first premolars, 70.9% were Vertucci's type I, followed by 10.4% type III, 7.18% type IV, 5.23% type II and 5.16% type V. In addition, among mandi...

Dental Research Journal, 2017

Background: The objective of this study was to systematically review prevalence of dental caries ... more Background: The objective of this study was to systematically review prevalence of dental caries at different water fluoride levels and emphasize fluoride concentration of drinking water and prevalence of dental caries. Materials and Methods: A comprehensive study was conducted using PubMed database. Inclusion criteria were predefined and some articles fulfilled these criteria. Study validity was assessed by some checklists. Surveys were conducted to determine prevalence of dental caries among individuals. Results: The heterogeneity in the group of children with deciduous teeth in terms of the amount of fluoride in drinking water and social class was significant, and the results of the studies in all the subgroups could not be pooled. However, the heterogeneity of group 2 for subjects with permanent teeth in terms of the fluoride level in drinking water and social class was not significant, and the results of the studies in each subgroup could be pooled together. Conclusion: The meta-regression showed that tooth type and social class had a significant association with the difference in the prevalence of dental caries. Therefore, these variables were the sources of heterogeneity, and the studies must be grouped and subgrouped based on these variables.