مجله دانشکده دندان پزشکی اصفهان
سال هفدهم شماره 1 (پیاپی 74، بهار 1400)

Zirconium oxide or zirconia have been usedfor the fabrication of dental implants due to their biocompatibility, hardness, toughness, compressive strength and chemical stability. The aim of this study is investigating the effect of sintering time on the properties of zirconia dental implant.

In this research, which was performed at Department of Dental and Biomedical Materials Science, Nagasaki University, Nagasaki, Japan, at 2019, zirconia-yttria mol.% 3 powder was pressed and sintered at 1450°C at different times (5 samplesfor each condition) and the effect of time on the phase, structural and mechanical properties of the sintered samples was investigated. One-way ANOVA statistical analysis was performed with the 0.05 level of significanceusing Graph Pad Prism 6software.

The results of XRD phase analysis show that sintering time change has a significant effect on the phase changes of the samples and the Vickers hardness of the samples shows a significant increase with increasing sintering time due to shrinkage and decrease in porosity of the samples. But the 12 hour times of sintering caused phase changes in the samples which is not desirable.

Therefore, for the fabrication of zirconia parts with minimum porosity and optimum hardness, a moderate sintering time (6 hours) is recommended.

Educating pediatricians regarding oral health and early childhood caries can have a great effect on improving their knowledge, attitude & practice. The aim of this study was to determine the knowledge, attitude & practice of pediatricians regarding oral health and early childhood caries in city of Isfahan.

In this descriptive-analytical study that is cross sectional, 80 pediatricians were selected randomly and a questionnaire that reliability and validity of it had been approved, was distributed between participants. Questions separately in terms of knowledge, attitude and practice regarding oral health and early childhood caries were designed. Finally, after collecting the questionnaires, Statistical analysis was performed using descriptive analysis (mean and standard deviation), Pearson correlation and Independent T-Testwith the 0.05 level of significance.

The mean knowledge score was 58.4, the mean attitude score was 79.2 and the mean practice score was 55.5 (from 100). There was a direct significant relationship between pediatricians’ knowledge score with attitude (p value < 0.001) and practice (p value < 0.001), in addition there was a direct significant relationship (p value < 0.001) between pediatricians’ attitude score and practice score too. There was no significant relationship between knowledge with age (p value = 0.12) but there was a significant relationship between attitude (p value = 0.01) and practice (p value < 0.001) with age. There was also a significant relationship between with knowledge (p value = 0.03), attitude (p value = 0.01) & practice (p value < 0.001).

The mean of pediatricians’ knowledge and practice score were average. Since there was a significant relationship between knowledge and practice score, so increase the pediatricians’ level of knowledge and improvement the attitude and practice of them in this context is important and developed training programs are necessary for them.

Many patients experience anxiety when they visit a dentist and anxiety causes an increase in the patient's blood pressure, as well as an injection of epinephrine, is also effective in increasing the blood pressure of the patients. The aim of this study was to investigate changes in blood pressure following injection of lower jaw blocking with lidocaine containing 1:80000 epinephrine and its association with anxiety level in patients.

In this cross sectional study, 129 patients referred to the dental school of Islamic Azad University of Khorasgan were selected and their blood pressure was measured before injection of anesthetic drug and ten minutes later. The anxiety level of the patients was determined using a dental anxiety inventory and the relationship between the level of anxiety and blood pressure in the patients before and after injection was measured. Data were analyzed by T-paired statistical test, regression and Pearson test.

There is a positive correlation between the patient's systolic and diastolic blood pressure before the injection and the anxiety score is significant (p value < 0.001).There was also a significant association between the degree of correlation between mean pressure and anxiety score(p value < 0.001). There was a positive and significant correlation between injection pressure and anxiety scores. (p value < 0.001).

Lidocaine injection containing epinephrine 1: 80,000 in patients undergoing mandibular block is associated with a significant increase in patients' systolic blood pressure. There was also a significant relationship between patients 'levels of anxiety and blood pressure, which had a greater effect on patients' blood pressure than epinephrine injections.

The knowledge and attitude of dentists toward the use of denture adhesives vary worldwide, and may be affected by different factors. Therefore, the current study aimed to assess the knowledge and attitude of the general dentists toward the use of denture adhesives.

In the current cross-sectional study that was donein 2019 in the city of Isfahan, the knowledge and attitude of 151 general dentists toward denture adhesive in the Isfahan city were assessed using a 16-item questionnaire. Besides, the participants' age and gender were recorded as well. Statistical analyses were done by One-way ANOVA and T-test with the 0.05 level of significance.

The liquid and powder (57.2%) forms of denture adhesives were the most prevalent favored types of adhesives. The incidence of adverse effects following the adhesives administration (55%) was the most common underlying etiology for the reluctance to use them. The mean of knowledge and attitude scores were (54.22 ± 14.37) and (43.32 ± 14.41), respectively, that both were at an intermediate level. Neither knowledge score (pvalue = 0.91) nor attitude score (p value = 0.06) was affected by gender. Similar insignificant associations were found for age (p value = 0.31 for knowledge and 0.37 for age) as well. A significant direct association was found between knowledge and attitude (p value = 0.02, r = 0.196).

Both of the knowledge and attitude of the studied population were in the intermediate range. Besides, neither their knowledge nor their attitude was affectedby age and gender. We observed that the attitude was directly associated with the dentists' knowledge

Dental anxiety in children is a challengein managing patients. The effect of this anxiety may continue until adolescence and be a reason for avoiding dental treatments.The aim of this study was compare the effectiveness of using music, 3D glasses and behavioral control methods on children’s anxiety during dental treatments.

This Experimental cross sectional study carried out on 96 children aged between 5-8 years without any systemic. The children were divided into three groups; control (basic behavior guidance techniques without distraction), audio (basic techniques plus music) and AV (basic techniques plus 3D AV) distraction groups. The anxiety score was assessed by using MCDASf method, before local anesthesia, after LA and after restoration. Pain rate measured with VAS and the behavior of children during dental treatment measured with Houpt index. Data were analyzed by one-way ANOVAwith the 0.05 level of significance.

The mean of anxiety in different stages before starting work, after anesthesia and after repair,was significantly different in the 3D glasses group (p value = 0.004), using music (p value = 0.018) and behavioral control(p value = 0.002). The lowest anxiety level in the 3D glasses group and the highest anxiety in the control group was. The best group in reducing the amount of pain after anesthesia and cooperationwas the 3D glasses group.

Use of 3D glasses in dental treatment can decrease dental anxiety in children. And children cooperation with 3D glasses was better than other methods.

Candida Albicans, has been suggested as a possible etiologic factor in the development of leukoplakia and oral squamous cell carcinoma. The aim of this study was to evaluate and compare the presence of Candida Albicans in samples with histopathological diagnosis of squamous cell carcinoma and dysplasia with healthy oral mucosa.

 Materials & Methods:

This retrospective descriptive-analytical study was carried out on 30 samples in three groups (10 samples per group) with histopathological diagnosis of squamous cell carcinoma, epithelial dysplasia, and healthy mucosa. To identify Candida, used special PAS staining and a 400X optical microscope. The results of study analyzed with Fisher exact testwith the 0.05 level of significance.

In the group diagnose with squamous cell carcinoma, Candida Albicans was present in 90% of the samples. In the other two groups with epithelial dysplasia and normal epithelium, positive PAS staining of candida was observed in 50% and 60 % samples respectively. A significant statistical difference between the group of squamous cell carcinoma and the other two groups was observed in terms of amount of Candida Albicans present in the samples. (p value < 0.05), however there was no such significant between the group with epithelial dysplasia samples and the one with normal epithelium samples (p value > 0.05).

According to the results of present study and the results of previous studies, it can be concluded that Candida Albicansprobably plays a role not as an etiological factor but as a factor leading to epithelial malignancies. We recommend more studies to be carried out on this topic.

Introduction:

Antidepressant drugs are the most commonly prescribed classes of pharmacologic agents in the public. The drugs have been shown to have a role in the regulation of bone cell function and as a result affecting the orthodontic tooth movements. The aim of thisstudy was to determine the effect of Amitriptyline and Sertraline on the tooth movement, root resorption and alveolar bone remodeling after load application in dogs.

In this experimental study, 9 male dogs were randomly divided into three groups, first group sertraline, second group Amitriptyline and the control group (normal saline). A nickel titanium spring (200 gr) was used between second premolar and canine after 1st premolar extraction. After 2 months, the reduction of distance between 2nd premolar and canine was measured. The percentages of root resorption and bone formation were determined. The data were analyzed using repeated measures analysis at significance level of 0.05.

In the three groups of amitriptyline, sertraline and control, the mean of teeth movement (p value = 0.483), external root resorption (p value = 0.608), total bone mineral density (p value = 0.078), bone formation percentage (p value = 0.616) and immature and lamellar bone formation (p value = 0.083), there was no statistical difference in any group and in premolar teeth

The rate of tooth movement and the percentages of bone formation and root resorption in dogs decreased with systemic administration of amitriptyline and sertraline; although this reduction was not statistically significant in comparison with control group.

Discoloration of resin composite restorations can lead to patient dissatisfaction. 0.2% Chlorhexidine and Persica mouthwashes are among the agents that cause discoloration. The aim of this study was to investigate the degree of discoloration caused by the0.2% Chlorhexidine and Persica mouthwashes on resin composite samples.

This in-vitro experimental study was conducted in Kashan and Isfahan School of Dentistry in 2020-2021. Number of 30 disc-shaped samples were fabricated from Charisma Diamond resin composite. The initial color of samples was measured by CIE Lab system in spectrophotometer. Then samples were divided into 3 groups (A, B, and C) (n = 10).The control group (A) was placed in distilled water, group B was immersed in the 0.2% Chlorhexidine mouthwash and group C was immersed in the Persica mouthwash. The color of the samples was measured again afterwards. Data were analyzed with One-way ANOVA and t-Test (α = 0.05).

The amount of l, a, b and ΔE after using 0.2% Chlorhexidine and Persica mouthwashes increased. The mean of Δl, Δa, Δb and ΔE showed significant differences between groups (p value < 0.05).

The discoloration of Persica mouthwash was more than 0.2% Chlorhexidine mouthwash and control group.Therefore, for patients with resin composite restorations, 0.2% Chlorhexidine mouthwash is better.

Radiography is a valuable adjunct to the diagnosis of periodontal disease. This study aimed to compare the accuracy of two periapical radiographic and digital biting techniques in assessing bone resorption in posterior teeth of patients with chronic periodontitis.

This descriptive-analytical study was performed on 36 samples of interproximal surfaces of posterior teeth in patients with chronic periodontitis, candidate of flap surgery referring to the department of periodontitis, faculty of dentistry, Islamic Azad University of Isfahan (Khorasgan) in 2015. First two methods of imaging include periapical and digital bitewing were performed and the necessary distances were measured by a radiologist. Then, during surgery, and before the bone contour correction, the distance from the reference point to the alveolar bone shaft (gold standard) was measured by a Williams probe. Data were analyzed using Paired t-test. (α = 0.05).

Out of 36 specimens, respectively in bitewing and periapical radiographs 2 and 1 cases were equal with clinical and in 16 (44.4%) and 20 (55.6%) distances were more. The average difference of amount of bone resorption in bitewing was 0.2 ± 0.12 mm and there was no significant difference between estimated mean value (p value = 0.01). Average difference of amount of bone resorption in periapical to clinical method was 0.87 ± 0.26 it was significant difference (p value = 0.001).

According to result, the use of bitewing radiography to determine the rate of bone resorption in posterior teeth is preferable to periapical radiography.

The surgical removal of impacted lower third molars involves trauma to soft and bony tissue and can result in pain, swelling and trismus. The purpose of this study was to evaluate the efficacy of dexamethasone, as a single 4 mg dose injected into the masseter muscle prior to extraction of impacted lower third molars on theses postoperative sequelae.

This prospective, randomized clinical research consisted of 43 healthy patients. The study group received 4 mg dexamethasone into the masseter muscle via intrabuccal approach immediately before starting the procedure while the control group received no corticoid. 7 days after surgery.Data were analyzed using t-test (α = 0.05)

The patients administered dexamethasone showed superior results after surgery in terms of oral aperture, pain and all the facial swelling parameters, with statistically significant differences versus the controls (p value<0.001). Also there was statistically significant difference in terms of patients trismus between case and control groups (p value<0.001).

The results obtained showed that 4 mg of dexamethasone injected into the masseter muscle in the immediately before starting the procedure significantly reduces swelling, trismus and pain

Fissuresealants are one of the most proven ways to prevent tooth decay. These materials may remain on the tooth for a long time, and other areas of the tooth may decay. The purpose of this study was to present the best method for surface preparation a fissure sealant material (Icon) and composite restoration .

In this experimental laboratory study, 40 samples of composite restorative material were prepared in 4 groups of 10 discs of 6 mm in diameter and 2 mm in height. Total etch bonding agent was used in the first, second and third groups without surface preparation, with the use of drills and 37% phosphoric acid, and after drilling, respectively. In the fourth group, self-etch bonding agent was used after drilling. After that, Icon resin material was placed on the surface of the composite in a disc of 4 mm with height of 2mm in diameter and was cured. When the samples were thermocycled and incubated, their bonding strength was evaluated with Instron testing machine. Data were analyzed by one-way variance statistical ANOVA tests, Tukey test(p value < 0.05).

The mean value of bond strength of Icon to resin composite was significantly different among the 4 groups (p value < 0.05). The fourth group presented the greatest bond strength value while the third group had the lowest bond strength.

When repairing fissure sealant, particularly Icon using resin composite, the best results of bond strength are achieved through surface roughening with drills and the application of self-etch bonding agents with a mild pH. Acidic etching agents (37% Phosphoric acid), however, have probably destructive effects on bond strength