مجله تحقیق در علوم دندانپزشکی
سال بیست و یکم شماره 1 (پیاپی 79، بهار 1403)

Providing painless treatment for patients in endodontic treatment is an effective factor in patient satisfaction and successful treatment. One of the reported methods to reduce pain is the use of cryotherapy. The aim of this study was to evaluate the effect of different cryotherapy methods on the success rate of alveolar inferior block injection in patients with symptomatic irreversible pulpitis during endodontic treatment.

In this interventional clinical trial study, 48 patients with symptomatic irreversible pulpitis in one of the 6 and 7 mandibular teeth was selected. Before starting work, the amount of pain was measured by VAS criteria to confirm the symptomatic diagnosis of irreversible pulpitis and patients were divided into 3 equal groups as control, cryotherapy of injection area and buccal vestibule area. In all 3 groups, the inferior alveolar block is injected. The acquisition of anesthesia was then assessed by cold spray and EPT. If one or both of these tests were positive, anesthesia was considered unsuccessful. If both the cold test and the EPT test are negative and the patient's pain during pulp exposure is less than 54 mm according to the VAS standard, the injection was considered successful and if it was more than 54 mm, anesthesia was considered unsuccessful. Data were analyzed by Chi-square, Fisher and Mann-Whitney tests

There was no significant difference in the success rate of anesthesia between the three groups (p = 0.715). There was no significant difference between sex and success rate of anesthesia in patients of all three groups (p = 0.619). The age of patients with successful and unsuccessful anesthesia was not significantly different (p = 0.247).

The success of block injection in cryotherapy at the injection site was higher than the other two groups, but in general there was no significant difference between the three groups in terms of success rate

Mouthwashes play an important role in oral hygiene and prevention of tooth decay by reducing the proliferation of oral microbial flora. The purpose of this study was to investigate the antibacterial and anti-biofilm activity of Persica herbal mouthwash, Mouthwashes with fluoride (Misswake), without fluoride (Irsha) and chlorhexidine 0.2% against Streptococcus mutans and Streptococcus sanguinis, in vitro.

To evaluate the antibacterial effect of mouthwashes on two standard strains of S. mutans and S. sanguinis, were used well diffusion and microbroth dilution methods and to examine their anti-biofilm effects, the microtiter plate method was used. The results were analyzed using SPSS software, version 21 and t-test.

In the well diffusion method, Misswake and 0.2% chlorhexidine mouthwashes had an inhibition zone at concentrations of 500 mg/ml and 500 mg/ml to 125 mg/ml, respectively. The MIC of Persica and Misswake mouthwashes were determined at concentration of 500 mg/ml and chlorhexidine 0.2% at concentration of 31.25 mg/ml. Irsha mouthwash did not have any antibacterial effect. In microtiter plate method, anti-biofilm activity was observed only for 0.2% chlorhexidine mouthwash at concentrations of 125 mg/ml to 31.25 mg/ml. Persica, Misswake and Irsha mouthwashes did not have any anti-biofilm effects on the studied bacteria. The results showed that 0.2% chlorhexidine had a significant antimicrobial and anti-biofilm effects on the studied bacteria compared to other mouthwashes (P<0.05).

0.2% chlorhexidine mouthwash has a very high antimicrobial power than other mouthwashes, but our study suggests that Persica and Misswake mouthwashes can be used as a mouthwash with proper antiseptic properties.

 NiTi instruments have a high risk of separation due to torsional or flexural fatigue (cyclic fatigue). Chemomechanical preparation and chemical disinfection causes the corrosion of endodontic instruments that may weaken the fracture resistance of the instruments. This study is to evaluate the two nickle-titanium systems’ (Neolix and X Pro Gold) resistance to fracture after immersion in sodium hypochlorite.

In this in vitro study, 32rotary files of Neolix file(Neolix,France) and X Pro Gold file (Easyinsmile,China),in size of 25 and 25 mm long were examined. The samples were divided into 2 groups of Neolix and X Pro Gold files(n=16). Then each group was divided into 2 subgroups: 2/5% sodium hypochlorite and normal saline based on the type of irrigation solution (n = 8). Cyclic fatigue test was performed with artificial canals in stainless steel blocks with a 60 ° angle of curvature and a radius of 5 mm.  The files used inside the artificial canals according to the manufacturer's instructions based on the torque (Neolix=1.5 N.cm and X Pro Gold=2.5 N.cm) and recommended speed (350 rpm), until they broke. Fracture time in seconds and number of cycles to failure (NCF) were calculated. The length of the broken piece was calculated in both files. Finally, the fractured surfaces of 2 samples from each group were randomly examined via scanning electron microscopy. SPSS software version 26 and two-way ANOVA test were used to analyze the data (p <0.05).

The average length of the broken piece was 4/95 mm in X Pro Gold file and 2/75 mm in Neolix file. Storing environment (p = 0.654) did not affect the number of cycles before fracture of the X Pro Gold and Neolix files,but file type (p<0.001) had an impact on it.

The results of this study showed that storing environment did not affect the number of cycles before fracture of X Pro Gold and Neolix files but file type affected them.Neolix file(NCF hypo=1098,NCF saline=1088) had a better performance than X Pro Gold file(NCF hypo=509 ,NCF saline=474).

Determination of the exact working length is one of the most important steps in root canal treatment. Various devices and methods, such as electronic apex locators, have been developed for the determination of the working length. The present study aimed to compare the accuracy of four electronic apex locators, DTE, Denjoy, Woodpecker and Coxo, in determining the actual working length.

In this descriptive study, fourty mandibular premolar teeth that fulfilled the inclusion criteria were selected and examined. First, each tooth was measured with four apex locators. The electronic measurements were performed following the manufacturers’ instructions within ±0.5 mm, ±1 mm and exactly at apical constriction. To calculate the actual working length, 4 mm of the root end was buccolingually cut from buccal side of the canal, and the distance between the coronal reference point and apical constriction was measured under a microscope. Then, data were analysed with Paired T test.

. Within ±0.5 mm from the apical constriction and at the apical constriction, the accuracy of apex locators DTE, Woodpecker, Coxo and Denjoy were 87% and 45%, 85% and 37%, 85% and 45% and 82% and 42%, respectively. All specimens measured with four types of apex locators were within the range of -1 to +1 mm to the apex with an accuracy of 97.5%.

 None of the four apex locators reported an accuracy of 100% at apical constriction. There was no statistically significant difference between the working length measured by four apex locators and the actual working length.

Staphylococcus aureus is one of the bacteria that make up the normal flora of the mouth and has been linked to conditions such as parotid infections. Parts of pomegranate were known to have antibacterial properties. Due to the properties for pomegranate and the importance of Staphylococcus aureus in the oral cavity, the incidence of dental caries and periodontal disease, finding and introducing a natural substance to replace chemical mouthwashes is crucial. in this study we investigated the antibacterial effect of pomegranate hydroalcoholic peel extract on staphylococous aureu.

For this experimental-laboratory study, Bacteria divided into 6 groups including: four groups of pomegranate peel extract with concentrations of 10, 25, 50 and 100 mg / ml, a positive control and a negative control group. Also, 3 bacterial samples were used to determine the MIC. disk diffusion test was used to measure the diameter of the growth inhibition zone. microdilution broth technique was used to evaluate the minimum concentration of bacterial growth inhibition (MIC). the obtained data were statistically analyzed by SPSS ver: 26 software. One way ANOVA test was used to examine the growth inhibition halo.

The overall results of inhibitory halo diameter evaluation showed that pomegranate extract had a inhibitory activity against Staphylococcus aureus. Bacteria were sensitive to a concentration of 25 mg / ml. That with increasing the concentration of the extract, the amount of antimicrobial effect on bacteria increases and a significant difference was shown between the diameter of the inhibition halo in four concentrations (P value <0.001) and the greatest effect was seen in 100 mg / ml concentration. In MIC study, the results showed that the effective amount of hydroalcoholic extract of pomegranate peel to prevent bacterial growth is in the range between 50 mg / ml.

According to the obtained results, the hydroalcoholic peel extract of pomegranate has antimicrobial effect and it seems that pomegranate extract can be consumed for antimicrobial use.

Biocompatibility of endodontic sealers plays an important role in the success of root canal treatment. Hence, this study was conducted to compare the cytotoxicity of bioceramic sealer ( Sure-Seal Root) and resin based sealer(Adseal), on mouse fibroblast cell line L929

In this experimental in vitro study, extraction of each sealer was obtained and incubated with dilutions of 1/2, 1/4 and 1/8 with fibroblast cell line for 48 hours in the cell culture media. MTT assay was employed to evaluate the cytotoxicity. Finally, the collected data were analyzed using One-way ANOVA and Tukey’s post-test . P<0.05 were considered statistically significant

MTT assay showed that higher dilutions of the tested materials resulted in higher viability of mouse fibroblast cell line L929. In both sealers, with increasing dilution, the survival rate of cells increased. Among two sealers, Adseal in all dilutions had lower cytotoxicity and higher cell viability percentage than sealer Sure-Seal Root ,showed that it was not significant in dilutions of 1/2and 1/8. respectively  (P=0.115) and (P=0.915), but it was significant in dilution of 1/4 .(P=0.001).

Under limitations of this invitro study ,results of this study showed that AD Seal showed less toxicity than Sure seal root in all dilutions.

The purpose of this study is to evaluate the effect of the type of zirconia (multilayer or monochrome) on the marginal and internal fit of a three-unit bridge.

In a maxillary model, the first premolar and first molar were prepared to receive 3-unit zirconia fixed dental prostheses and then scanned. Each scan was used to make two bridges (one with multi-layer and the other with monochrome zirconia). With Exocad software, the bridge was designed and then milled. The bridges milled in the previous stage were evaluated and compared with the replica method in terms of internal and marginal fit. For statistical analysis, an independent t-test was used to evaluate marginal, cervical, and axial fit, and the Mann-Whitney test was used to evaluate occlusal fit. (P = 0.05)

The average marginal and cervical gaps in monochrome zirconia were 65.30±20.00 and 72.42 ±10.11 micrometers, respectively, and in multi-layer zirconia were 70.76±14.71 and 78.74±11.91 micrometers, and this difference was not statistically significant (P>0.05). The average axial and occlusal gaps in monochrome zirconia were 102.5±10.70 and 118.9±18.52 micrometers respectively and in multilayer zirconia 114.8±18.88 and 141.6±29.88 micrometers, this difference was statistically significant and the average gap in monochrome zirconia was less than multilayer zirconia (P<0.05).

Monochrome zirconia restorations show similar marginal and internal fit compared to multilayer zirconia restorations. Although the occlusal and axial gap in multi-layer zirconia is more than in monochrome zirconia, it is within the clinically acceptable range. Multilayer zirconia is generally clinically usable.

  Diabetes may increase the incidence of tooth decay due to dry mouth and high blood sugar levels. Identifying the factors influencing oral health behaviours in diabetic patients is thus an essential step toward promoting oral and dental health. As a result, this study aimed to predict oral health in people with diabetes and compare them to healthy people.

The available sampling method was used to conduct this study from  2021 to 2022. The study group consisted of 261 persons (men and women), 131 of whom were healthy and 130 of whom were unhealthy (diabetic), and information was gathered through a questionnaire, medical records, and an examination. These people looked at six variables: age, gender, decayed teeth, extracted teeth, filled teeth, and oral health index. Using the Spss Modeler program, two decision tree methods and a support vector machine and spss Modeler soft ware were used.

The most important findings of decision tree analysis are 1- If the person's age is less than or equal to 37 years, then the person is 100% healthy. 2- If the age is over 37 years and the number of decayed teeth is less than the average of 7, and we do not have any extracted teeth, there is an 82% chance of diabetes. If the age is over 37 and the number of decayed teeth is less than the average of 7, and the number of extracted teeth is more than 1, then people under the age of 49 with an OHI index greater than 0.9 are 100% diabetic. Also, the total accuracy of the linear support vector machine is 70.73%, which indicates that decayed teeth with the least amount of weight have little effect on diabetes or health.

 Decision tree algorithms and support vector machines could predict oral and dental health in diabetic patients.

Avulsion is one of the most serious dental traumas. Since children spend most of their time at school after home, teacher’s knowledge of dental trauma will affect prognosis of traumatized teeth. The aim of this study was evaluation of Special elementary school teachers’ knowledge, regarding emergency management of avulsion in Esfahan.

Methods  and material:

 In this cross-sectional analytical study, a standard questionnaire was given to all primary education teachers in Isfahan who were selected by census method and information was collected. Data were analyzed by ANOVA test, and t-test.

3.3% of teachers had very low knowledge, 60% low knowledge, 32.3% moderate knowledge, 3.3% high knowledge and 1.1% very high knowledge of avulsion management. Between teachers' knowledge and age (P = 0.034), history of attending first aid course (p = 0.038), dental emergency’ courses (P = 0.010) and experience of dealing with avulsion trauma (p = 0/007) was a direct connection. But no relationship was found between knowledge and gender (p = 0.139), level of education (P = 0.302), teaching experience (P = 0975) and the school type where they work (P = 0.587).

More than half of Special elementary school teachers had less than average knowledge of avulsion emergency management and most of them did not participate in a training course for avulsion management. Therefore, it is necessary to make plans to increase the knowledge of special school teachers.

The purpose of this review is to collect the oral-facial complications caused by the covid-19 vaccines and to know the reasons for their occurrence.

An electronic search without date restrictions was performed in the MEDLINE databases through PUBMED and google scholar. Among the 50 studies after removing duplicates, 11 articles that met the inclusion criteria were reviewed and included in the study.

Studies have shown that the injection of Covid-19 vaccines may cause oral side effects such as lichen planus, erythema multiforme, Steven Johnson syndrome, mucositis, and Bell's palsy. Bell's palsy (6023 cases), skin and mucosa itching (39 cases), erythema multiforme (6 cases), lichen planus (6 cases), Steven Johnson syndrome (3 cases), mucositis (1 case), angular cheilitis (1 case) ), pemphigus vulgaris (1 case) and one case with unknown cause. Pfizer vaccine is the most complicated vaccine reported in this study.

Considering the high prevalence of covid-19 and the subsequent injection of covid-19 vaccines in order to prevent this disease, diagnosis and treatment of possible complications, especially oral and facial complications after vaccination, are of great importance.