Papers by amir mirhashemi
Frontiers in Public Health, Sep 14, 2022
The purpose of the present study was to investigate the association of COVID-vaccination with the... more The purpose of the present study was to investigate the association of COVID-vaccination with the quality and quantity of sleep, the level of stress, and temporomandibular joint (TMJ) disorders (TMDs) in Iranian dental students. Materials and Methods: In this cross-sectional research, we applied a questionnaire including questions on the Perceived Stress Scale (PSS), sleep quality and quantity, Diagnostic Criteria for Temporomandibular Disorders (DC/TMD), and vaccination status. All vaccinated students of the dental schools located in the city of Tehran were invited to participate in the study. Participants were divided into three groups: those vaccinated for less than a month, those vaccinated for-months, and those vaccinated for more than months. A paired t-test served for statistical analysis. Results: Overall, out of students (. %) completed the questionnaire, among which individuals were fully vaccinated, and were included in the data analysis. Stress levels decreased (mean di erence = −. , p-value = .) and sleep quality and quantity improved mostly-months after the vaccination (mean di erence = −. , p-value = .). However, TMD symptoms were mostly alleviated in people vaccinated for more than months (mean di erence = −. , p-value < .). In this respect, no significant di erence was observed between the two genders. Conclusion: According to the results of the study, vaccination was associated with the improvement of psychological consequences of the COVIDpandemic. It is recommended that further longitudinal studies be conducted on larger sample sizes and di erent age groups by using various data collection methods (especially regarding the assessment of TMD).
Dental Research Journal, 2021
Background: Antimicrobial nanoparticles (NPs) have various applications in different fields of de... more Background: Antimicrobial nanoparticles (NPs) have various applications in different fields of dentistry. The purpose of incorporating NPs into orthodontic adhesives is to inhibit the cariogenic bacteria and reduce decalcifications around bonded orthodontic brackets. However, they may affect the physical and mechanical properties of adhesive such as shear bond strength (SBS). This review was done to answer the question whether the incorporation of antimicrobial NPs into orthodontic adhesives changes the SBS. Materials and Methods: An electronic search was performed with keywords such as adhesives AND nanoparticles AND orthodontics AND shear strength. After screening and applying eligibility criteria, 18 relevant studies were included. Results: The pooled data suggest that except for 10 wt% of various NPs incorporation, there is no significant difference in SBS between control conventional adhesives and experimental modified ones with tested concentrations. Conclusion: The SBS of orthodontic adhesives containing up to 5% NPs is in clinical acceptable range. However, generalizing the results to in vivo situation may be problematic and further studies are required.
Copyright © 2015, Trauma Monthly. This is an open-access article distributed under the terms of t... more Copyright © 2015, Trauma Monthly. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 Inter-
Introduction : The aim of this study is to define the trend of the orthodontists and the surgeons... more Introduction : The aim of this study is to define the trend of the orthodontists and the surgeons in the borderline Class III patients and assess their satisfaction after the surgery. Materials and Methods : The study population consisted of 31 patients (16 female and 15 male) with the average age of 21 years, whose final occlusion 2 months after the surgery was perfect. The amount of reverse overjet was less than 5 mm in all patients. Surgeons and orthodontists made their treatment plan separately and if there were any differences, the surgeon and orthodontist would discuss it and the patient would be treated by the best treatment plan. The patients’ satisfaction at least 5 months after orthognathic surgery was assessed quantitatively by means of a visual analogue scale (VAS) of 10 cm. Result : Among 31 patients entered in this study, orthodontists suggested two-jaw surgery for 61% of patients while surgeons suggested two-jaw surgery for 45% of patients. In 35% of patients, the ort...
Orthodontic Waves, 2017
Purpose: Elastomeric chains are widely used for exerting force in orthodontics. Since orthodontic... more Purpose: Elastomeric chains are widely used for exerting force in orthodontics. Since orthodontic patients are prone to plaque accumulation they are usually advised to apply antibacterial agents. The aim of this study was to compare the effects of three different mouthwashes including persica, chlorhexidine, sodium fluoride and the combination of chlorhexidine and sodium fluoride on force decay of orthodontic elastomeric chains. Materials and methods: In this study, 315 pieces of elastomeric chains were divided into 5 groups: persica, chlorhexidine 0.2%, sodium fluoride 0.2% and the combination of chlorhexidine and sodium fluoride and a control group. The samples were kept in artificial saliva and were soaked in the mouthwashes twice a day for 60s each time. The control group was kept in artificial saliva throughout the day. The forces exerted by the samples were measured by a universal testing machine at initial, 1 day, 7, 14 and 28 days. To compare the results, repeated measure ANOVA was performed. Results: A significant force-degradation over time was observed in all groups (p< 0.005). However, there were no significant differences among study groups and between study groups and the control group. Conclusions: Application of persica, chlorhexidine, sodium fluoride and the combination of chlorhexidine and sodium fluoride mouthwashes had no adverse effect on the forcedegradation of orthodontic elastomeric chains.
Frontiers in Dentistry
The main goals of treatment of dentofacial deformities are to achieve optimal esthetics and ideal... more The main goals of treatment of dentofacial deformities are to achieve optimal esthetics and ideal functional occlusion. The conventional orthognathic surgical approach includes a long presurgical orthodontic phase, which takes about 18 months. During this phase, the patients’ appearance is deteriorated and their motivation to continue treatment significantly decreases. In the surgery first approach (SFA), orthognathic surgery is performed prior to orthodontic treatment, and orthodontic treatment is performed postoperatively to improve dental occlusion and for final settling. The SFA has two main advantages namely shortening of treatment period, and early improvement of the appearance of patient. The SFA has significant advantages especially for class III patients. This study aimed to review the available articles on this topic published from 2012 to 2019 to achieve a comprehensive understanding of different aspects of the SFA. The databases were searched by two researchers and a tot...
Photodiagnosis and Photodynamic Therapy, 2022
AIM AND OBJECTIVES the aim of this study was to evaluate the effect of the photodynamic therapy w... more AIM AND OBJECTIVES the aim of this study was to evaluate the effect of the photodynamic therapy with riboflavin and curcumin's effect on the shear bond strength (SBS) of the orthodontic composites. METHOD AND MATERIAL A total of 45 human premolar teeth were used in this study. All teeth were examined under a stereomicroscope. The samples were divided into 3 groups including no intervention (control group), aPDT with riboflavin and 460 nm diode laser and aPDT with curcumin and 460 nm diode laser. After aPDT procedure,orthodontic brackets were bonded to enamel surfaces. Then, the samples were thermocycled for 3000 cycles. The brackets were then debonded using a universal testing machine. The adhesive remnant index (ARI) score was assessed. ANOVA with Post-hoc test was used to compare the SBS values between groups. RESULTS The highest SBS mean value was presented in curcumin group (25.95±3.68) whereas, the lowest SBS mean value was observed in riboflavin group (22.19±4.73). The mode of failure was mostly score 1 and score 2 in all groups. There was no significant difference in SBS values and ARI score between groups. Scanning electron microscope of the curcumin group and control showed the honey comb structure, while the microscopic view of the riboflavin group lacked this structure and had less porosity and irregularity after etching. CONCLUSION Riboflavin and curcumin mediated antimicrobial photodynamic therapy both have acceptable the bond strength of orthodontic brackets and can use before bonding for reduce inflammation and microbial attact.
Objectives: Nitric oxide (NO) is a signaling molecule that mediates mechanical bone loading. Cycl... more Objectives: Nitric oxide (NO) is a signaling molecule that mediates mechanical bone loading. Cyclic guanosine 3', 5' monophosphate (cGMP) is a NO-induced effector molecule. The aim of this study was to assess the effect of NO-cGMP pathway on orthodontic tooth movement (OTM) in rats by use of two phosphodiesterase 5 (PDE5) inhibitors namely sildenafil and tadalafil as chemical tools. Materials and Methods: Forty-five male Wistar rats were divided into three equal groups (n=15) based on the substance they received. The first group received daily injections of tadalafil; the second group received daily injections of sildenafil and the third group received daily injections of normal saline. The orthodontic appliances consisted of nickel-titanium closed-coil spring ligated between the maxillary right incisor and the first molar of the animals for 21 days. The amount of tooth movement was measured in all three groups at the end of this period. Histological analysis was performed t...
Journal of Dental Medicine, 2015
1 وضع زکرم تاقیقحت شزپنادند ک ی و رایداتسا هورگ یشزومآ ،سکیتندوترا هدکشناد ،یکشزپنادند هاگشناد مو... more 1 وضع زکرم تاقیقحت شزپنادند ک ی و رایداتسا هورگ یشزومآ ،سکیتندوترا هدکشناد ،یکشزپنادند هاگشناد مولع یکشزپ و تامدخ ،یتشادهب ینامرد ،نارهت ،نارهت ناریا 2 داتسا هورگ یشزومآ ،سکیتندوترا هدکشناد ،یکشزپنادند هاگشناد مولع یکشزپ و تامدخ ،یتشادهب ینامرد ،نارهت ،نارهت ناریا 3 رایشناد هورگ یشزومآ ،سکیتندوترا هدکشناد ،یکشزپنادند هاگشناد مولع یکشزپ و تامدخ ،یتشادهب ینامرد ،نارهت ،نارهت ناریا 4 رایتسد یصصخت هورگ یشزومآ ،سکیتندوترا هدکشناد ،یکشزپنادند هاگشناد مولع یکشزپ و تامدخ ،یتشادهب ینامرد ،نارهت ،نارهت ناریا
Resume Objectif Le but de cette etude etait d’evaluer l’effet de la carbamazepine et de l’acide v... more Resume Objectif Le but de cette etude etait d’evaluer l’effet de la carbamazepine et de l’acide valperoique sur le deplacement dentaire chez des rats Wistar mâles. Methodes L’evaluation du deplacement dentaire apres 21 jours de perfusion medicamenteuse a ete realisee par une jauge d’epaisseur. La densitometrie osseuse a ete evaluee sur des teleradiographies de profil prises respectivement a j 1 et a j 21. Apres une dissection du maxillaire, les parametres histologiques ont ete evalues. Resultats Le deplacement orthodontique des dents a ete accelere dans les groupes experimentaux et pas dans les groupes temoins ou la densite osseuse augmente de facon significative. Sur les coupes histologiques, on observe que la portion mesioapicale du ligament parodontal est plus large dans les groupes experimentaux. Il en est de meme pour la portion distoapicale du ligament parodontal qui est plus large uniquement dans le groupe qui a recu de l’acide valproique. Conclusion L’acide valproique et la ...
Lasers in Medical Science, 2018
This study investigated the effect of Er:YAG (smart 2940 Dplus, DEKA, Italy) and Er:CrYSGG (Water... more This study investigated the effect of Er:YAG (smart 2940 Dplus, DEKA, Italy) and Er:CrYSGG (Waterlase iPlus, Biolase, USA) lasers on the shear bond strength (SBS) between the orthodontic brackets and dental porcelain in comparison with conventional acid etching with 9% hydrofluoric acid (HF, Ultradent, USA). A total of 60 specimens of maxillary incisor crown were prepared and randomly assigned to five groups; each group was subjected to a different porcelain surface conditioning: (1) etching with the 9% HF for 2 min; (2) etching with the 9% HF for 2 min followed by irradiation with the Er:CrYSGG laser (3-W power, 10-Hz frequency for 10 s); (3) etching with the 9% HF for 2 min followed by irradiation with the Er:YAG laser (3-W power, 10-Hz frequency for 10 s); (4) Irradiation with the Er:CrYSGG laser (3-W power, 10-Hz frequency for 10 s without acid etching) and (5) irradiation with the Er:YAG laser (3-W power,10-Hz frequency for 10 s without acid etching). After using Transbond XT primer and Transbond XT adhesive, the metal brackets (Dentaurum, Germany equilibrium 2, optimal design) bonded to the conditioned porcelain surface. Subsequently, the specimens were thermocycled for 5000 cycles and then debonded using the Universal Testing Machine (Zwick). In each group, one specimen was not bonded to brackets to allow further examination with electron microscopy. After debonding, the specimens were examined by stereomicroscope to determine their adhesive remnant index (ARI). The average SBS [Mean (SD)] values in the five groups were as follows:
Lasers in Medical Science, 2018
This study investigated the effect of Er:YAG (smart 2940 Dplus, DEKA, Italy) and Er:CrYSGG (Water... more This study investigated the effect of Er:YAG (smart 2940 Dplus, DEKA, Italy) and Er:CrYSGG (Waterlase iPlus, Biolase, USA) lasers on the shear bond strength (SBS) between the orthodontic brackets and dental porcelain in comparison with conventional acid etching with 9% hydrofluoric acid (HF, Ultradent, USA). A total of 60 specimens of maxillary incisor crown were prepared and randomly assigned to five groups; each group was subjected to a different porcelain surface conditioning: (1) etching with the 9% HF for 2 min; (2) etching with the 9% HF for 2 min followed by irradiation with the Er:CrYSGG laser (3-W power, 10-Hz frequency for 10 s); (3) etching with the 9% HF for 2 min followed by irradiation with the Er:YAG laser (3-W power, 10-Hz frequency for 10 s); (4) Irradiation with the Er:CrYSGG laser (3-W power, 10-Hz frequency for 10 s without acid etching) and (5) irradiation with the Er:YAG laser (3-W power,10-Hz frequency for 10 s without acid etching). After using Transbond XT primer and Transbond XT adhesive, the metal brackets (Dentaurum, Germany equilibrium 2, optimal design) bonded to the conditioned porcelain surface. Subsequently, the specimens were thermocycled for 5000 cycles and then debonded using the Universal Testing Machine (Zwick). In each group, one specimen was not bonded to brackets to allow further examination with electron microscopy. After debonding, the specimens were examined by stereomicroscope to determine their adhesive remnant index (ARI). The average SBS [Mean (SD)] values in the five groups were as follows:
Lasers in Medical Science, 2015
The aim of the present study was to assess the effect of laser-assisted bleaching with neodymium:... more The aim of the present study was to assess the effect of laser-assisted bleaching with neodymium:yttrium-aluminum-garnet (Nd:YAG) and diode lasers on shear bond strength (SBS) of orthodontic brackets. One hundred and four extracted human premolars were randomly divided into four groups: group 1: No bleaching applied (control group); group 2: Teeth bleached with 40 % hydrogen peroxide; group 3: Teeth treated with 30 % hydrogen peroxide activated with Nd:YAG laser (1064 nm, 2.5 W, 25 Hz, pulse duration of 100 μs, 6 mm distance); and group 4: Teeth treated with 30 % hydrogen peroxide activated with diode laser (810 nm, 1 W, CW, 6 mm distance). Equal numbers of teeth in groups 2, 3, and 4 were bonded at start, 1 h, 24 h, and 1 week after bleaching. A universal testing machine measured the SBS of the samples 24 h after bonding. After bracket debonding, the amount of residual adhesive on the enamel surface was observed under a stereomicroscope to determine the adhesive remnant index (ARI) scores. The SBS in the unbleached group was significantly higher than that in the bleached groups bonded immediately and 1 h after laser-assisted bleaching (P &amp;amp;amp;amp;amp;amp;lt; 0.05). In groups 3 and 4 at start and group 2 at start and 1 h after laser-assisted bleaching, the SBS was found to be significantly lower than that in the control group. Significant differences in the ARI scores existed among groups as well. The SBS of brackets seems to increase quickly within an hour after laser-assisted bleaching and 24 h after conventional bleaching. Thus, this protocol can be recommended if it is necessary to bond the brackets on the same day of bleaching.
Photomedicine and Laser Surgery, 2013
The aim of this study was to compare the effects of three enamel etching modes-laser-etch, self-e... more The aim of this study was to compare the effects of three enamel etching modes-laser-etch, self-etch and acid-etch (5, 10 and 15 s)-on bracket bonding, using a universal adhesive. Methods: Eighty-four maxillary premolars were randomly divided into seven groups (n=12) based on the etching method and the adhesive used for bracket bonding. After water storage and thermocycling, shear bond strength was measured, and adhesive remnant index scores on debonded enamel were determined. Results: There were significant differences between the seven groups regarding bond strength values (p < 0.001). The highest values were observed in universal adhesive with laser etching group, while Transbond XT with acid or laser etching, and universal adhesive used in self-etch mode demonstrated the lowest bond strength. The universal adhesive with the three different etching times presented with statistically similar results, all showing an improvement in bond strength, compared with Scotchbond universal (SBU)/SE. Conclusions: The universal adhesive evaluated in the present study demonstrated statistically similar bond strengths to conventional orthodontic adhesive in self-etch mode. The bond strength can be improved by adding an initial acid etching or laser conditioning step, although enamel damage was observed in some cases.
Journal of Dentistry of Tehran University of Medical Sciences, 2016
Nitric oxide (NO) is a signaling molecule that mediates mechanical bone loading. Cyclic guanosine... more Nitric oxide (NO) is a signaling molecule that mediates mechanical bone loading. Cyclic guanosine 3', 5' monophosphate (cGMP) is a NO-induced effector molecule. The aim of this study was to assess the effect of NO-cGMP pathway on orthodontic tooth movement (OTM) in rats by use of two phosphodiesterase 5 (PDE5) inhibitors namely sildenafil and tadalafil as chemical tools. Forty-five male Wistar rats were divided into three equal groups (n=15) based on the substance they received. The first group received daily injections of tadalafil; the second group received daily injections of sildenafil and the third group received daily injections of normal saline. The orthodontic appliances consisted of nickel-titanium closed-coil spring ligated between the maxillary right incisor and the first molar of the animals for 21 days. The amount of tooth movement was measured in all three groups at the end of this period. Histological analysis was performed to assess root resorption lacunae, o...
Journal of Dental Medicine, 2015
1 داتسا هورگ یشزومآ ،سکیتندوترا هدکشناد ،یکشزپنادند هاگشناد مولع یکشزپ و تامدخ ،یتشادهب ینامرد ،ن... more 1 داتسا هورگ یشزومآ ،سکیتندوترا هدکشناد ،یکشزپنادند هاگشناد مولع یکشزپ و تامدخ ،یتشادهب ینامرد ،نارهت ،نارهت ناریا 2 ینامرد ،یتشادهب تامدخ و یکشزپ مولع هاگشناد ،یکشزپنادند هدکشناد ،سکیتندوترا یشزومآ هورگ رایداتسا و یکشزپنادند تاقیقحت زکرم وضع ،نارهت ،نارهت ناریا 3 سکیتنادویرپ یشزومآ هورگ یصصخترایتسد ، یکشزپنادند هدکشناد ، و یکشزپ مولع هاگشناد یتشادهب تامدخ ، نارهت ینامرد ، ناریا ،نارهت 4 تسیژولویمدیپا ، هورگ یشزومآ تشادهب هدکشناد ،یتسیز رامآو يژولویمدیپا ، یتشادهب تامدخو یکشزپ مولع هاگشناد ، ناریا ،نارهت ،نارهت ینامرد
Background and Aim: mandibular setback surgery is one of the common treatments in patients with m... more Background and Aim: mandibular setback surgery is one of the common treatments in patients with mandibular prognathism. In this surgery, the mandible is placed backward from its original position, and as a result, the soft tissue, tongue, and hyoid bone are slightly displaced, all of which can affect the dimensions of the airway. Given that these changes in the dimensions of the airway can lead to obstructive sleep apnea, it is important to examine these changes and their stability. In this regard, cephalometric radiography can be used, which haslowcost and dose in comparison to 3D radiographs, to examine changes in airway dimensions. The aim of this study was to evaluate the short-term and long-term changes in airway dimensions following mandibular steback surgery with the help of cephalometric radiography. Methods: The study was conducted by review method. Using the keywords 'orthognathic surgery,' 'mandibular setback,' 'Malocclusion angle class III,' '...
Journal of Dental Medicine, 2020
١ رايشناد هورگ يشزومآ سكيتندوترا ، هدكشناد ،يكشزپنادند هاگشناد مولع يكشزپ و تامدخ ،يتشادهب مرد ين... more ١ رايشناد هورگ يشزومآ سكيتندوترا ، هدكشناد ،يكشزپنادند هاگشناد مولع يكشزپ و تامدخ ،يتشادهب مرد ينا ،نارهت ،نارهت ناريا ٢ كشزپنادند ، هدكشناد ،يكشزپنادند هاگشناد مولع يكشزپ و تامدخ ،يتشادهب ينامرد ،نارهت ،نارهت ناريا ٣ وجشناد ي زاسوراد ي ، زاسوراد هدكشناد ي ، ملاسا دازا هاگشناد ي ا نارهت ي نار ٤ ايتسد يصصخت ر هورگ يشزومآ سكيتندوترا ، هدكشناد ،يكشزپنادند هاگشناد مولع يكشزپ و تامدخ ،يتشادهب رد ينام ،نارهت ،نارهت ناريا
Journal of Dentistry (Tehran, Iran), 2016
Objectives: Nitric oxide (NO) is a signaling molecule that mediates mechanical bone loading. Cycl... more Objectives: Nitric oxide (NO) is a signaling molecule that mediates mechanical bone loading. Cyclic guanosine 3′, 5′ monophosphate (cGMP) is a NO-induced effector molecule. The aim of this study was to assess the effect of NO-cGMP pathway on orthodontic tooth movement (OTM) in rats by use of two phosphodiesterase 5 (PDE5) inhibitors namely sildenafil and tadalafil as chemical tools. Materials and Methods: Forty-five male Wistar rats were divided into three equal groups (n=15) based on the substance they received. The first group received daily injections of tadalafil; the second group received daily injections of sildenafil and the third group received daily injections of normal saline. The orthodontic appliances consisted of nickel-titanium closed-coil spring ligated between the maxillary right incisor and the first molar of the animals for 21 days. The amount of tooth movement was measured in all three groups at the end of this period. Histological analysis was performed to assess...
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Papers by amir mirhashemi