مجله تحقیق در علوم دندانپزشکی
سال هفدهم شماره 1 (پیاپی 63، بهار 1399)

Allografts are a group of grafting materials in two types of DFDBAs and FDBAs with various applications in restoration of osseous defects. Considering high price of foreign brands of these materials, we decided to launch a study and compare 2 types of FDBA and DFDBA osseous powders manufactured by Faravardehaye Peyvandi Iran Company and their application in restoration of calvaria bone damages in rabbits.

The research performed on randomized clinical trial on 12 white rabbits.We made 4 full thickness 8 millimeter defects in calvaria bones of each rabbit. Then, in two groups, DFDBA and FDBA were used and other two groups were the positive and negative control group. Within the 2 consecutive months (2,4,6, and 8 weeks) every session, 5 rabbits were sacrificed and removed the calvaria bone for histologic and histomorphometric study. Data were analyzed using Friedman and Kruskal-Wallis and Wilcoxon tests. We utilized SPSS ver:20 software.

There were no statistically significant differences between FDBA and DFDBA groups regarding the inflammation and amount of resorption .In the filling status of the defect, DFDBA group was significantly better than FDBA group. (p<0.05) At the end of 4 weeks in both groups, bone powder was completely absorbed. Foreign body reaction and complete remodeling of bone was not observed in both groups during the study period.

Both FDBA and DFDBA groups were similar regarding the inflammation and amount of resorption. In the filling status of the defect, DFDBA group was preferred vs. FDBA group.

Post extraction Bleeding is a well-known and frequent complication that can continue for 8-12 hours after surgery and if not controlled, it can create a range of complications from a simple hematoma to a large amount of blood loss. Calcium alginate dressing, can result in  hemostasis and accelerate healing of tissue. The aim of this study was to determine the effect of calcium alginate dressing, compared to conventional dressing on bleeding and complications after tooth extraction.

The study was a clinical trial (Split mouth).This study was performed on 30 patient and 60 Samples referred to the Oral and Maxillofacial surgery department, who needed bilateral simple extraction in one jaw, which did not have the exclusive criteria. Two teeth of each jaw were randomly divided into two groups of control and case group. In the case group, after removing the tooth, we used calcium alginate dressing, and in the control group, we used the conventional dressing (gaz). The  groups were assessed for bleeding, at one hour and 24 hours after tooth extraction and also, at the third and seventh day after extraction. The pain was evaluated by VAS criteria at 10 degrees and the dry socket was evaluated based on BLUM criteria and tissue healing (by Healing Scale) at 10 degrees from 0 to 9. These indices were analyzed by MANN-U-WHITNEY test in two groups.

Study was conducted on 30 patients and 60 samples (17 male and 13 females) with a mean age of 33±6.5.Bleeding in one hour after extraction in the control group was 66.7% and in the calcium Alginate group was 43.3%(p<0.06). Bleeding after 24 hours was 26.7% in the control group and 3.3% in the case group (p<0.02). At the third day, the pain level in the control group was 1.8±1.3 and in the case group was 2.1 ±1.5(p<0.4). Healing in the control group was 6.37±1.7 and in the case group was 6.4±2.2(p˂0.8). Dry socket occurrence in the control group was 6.7% and in the case group was 3.3%(p<0.7). On the seventh day follow up, the pain level in the control group was 0.9 ±0.8 and in the case group was 0.9±0.7(p<0.8). The healing rate and dry socket occurrence were similar in both groups.

This study showed that calcium alginate dressing reduced the amount of bleeding after tooth extraction significantly, but is not affect the other complications.

Dental caries is a major health problem nowadays. polyphenolic compounds of tea can exert its anti-cariogenic effects by affecting the cariogenic Streptococcus Mutans bacteria. The aim of this study was to investigate the antimicrobial effect of ethanolic, methanolic and aqueous extracts of green tea in comparison with chlorhexidine on Iranian strain of this bacteria.

10 g of green tea powder was dissolved in 100 mg of ethanol, methanol and aqueous solvents separately. After one week, the obtained solutions were filtered and 100mg / ml solution was extracted. to evaluate the diameter of inhibition, zone The Swabs impregnated with suspension scrubbed on culture medium. the extracts were injected onto special paper discs and the impregnated disks were placed on the bacterial culture media, plates were kept in the incubator for 24 hours at 37 °C and then the diameter of inhibition zones was calculated. Using Muller Hinton Broth, herbal extracts were made at concentrations 1:2 (50 mg/ml) and 1:4 (25 mg/ml) and 1:8 (12.5 mg/ml) and 1:16 (6.25 mg/ml) and 1:32 (3.125 mg/ml). Then, 100 μl microbial suspensions made by standard McFarland 0.5 were transferred to all test tube. The test tubes were placed in an incubator at 37°C for 24 hours. After 1 day, contents of all test tubes were separately cultured on Muller Hinton Broth medium. The culture media were incubated at 37°C for 1 day. The results were evaluated in the form of growth or non-growth of bacterial colonies on culture media and MBC and MIC were determined. ANOVA and Post hoc test was used for statistical analyze with SPSS Software.

Experimental results after three iterations showed mean values of 16.16, 16.66, 12.5 and 17.5 mm for diameter of the inhibition zone of ethanolic, methanolic and aqueous extracts and chlorhexidine 0.2%, as control. Also, at the significant level of 0.05, there was no significant difference between the diameter of the inhibition zone of ethanol, methanol and chlorhexidine extracts. (p>0.05)The Aqueous Extract Showed Significant difference with other Extracts. MBC Reported 12.5mg/ml for Ethanolic and 50mg/ml for two other extracts. MIC Reported 6.25mg/ml for ethanolic and 25mg/ml for two other extracts.

The results showed that the antimicrobial effects of ethanolic and methanolic extract of Iranian green tea are higher than aqueous extract and there is no significant difference between these two extracts with Chlorohexidine.

One of the major problems of all ceramic restorations is their probable fracture against the occlusal force. The aim of the present in vitro study is to compare the effect of three marginal designs (shoulder, sloped shoulder, chamfer) on the fracture resistance of monolithic zirconia crowns.

In this in vitro study, three PEEK dies with chamfer finish line design (0.8 mm depth), shoulder finish line design (1 mm depth) and sloped shoulder finish line design (1 mm depth) was prepared using milling machine. Thirty epoxy resin dies (10 samples chamfer, 10 samples sloped shoulder, 10 samples shoulder) were made. Monolithic Zirconia crowns with 35μm cement space fabricated on the 30 epoxy resin dies in a dental laboratory. Then the zirconia crowns were cemented on the epoxy resin dies and underwent a fracture test with a universal testing machine STM-20 (SANTAM, Tehran, Iran) and samples were investigated from the point of view of the origin of the failure. All tests were performed in SPSS ver.22 software.

The mean value of fracture resistance for the shoulder margins was 3965.80±417.52 N, for the chamfer margins was 4910.40±1002.83 N and for the sloped shoulder was 4490.90±898.48 N. The One-way ANOVA analysis revealed a statistically significant difference between groups (P=0.049) and Tukey post hoc analysis showed that fracture resistance of Chamfer group was significantly higher than Shoulder group (P<0.05).

The result of this study indicates that marginal design of the zirconia crowns effects on their fracture resistance. A chamfer margin could improve the biomechanical performance of single zirconia crown restorations.

Alzheimer’s disease is a degenerative and progressive disorder resulting in cognitive impairment. Tooth loss is suggested as a significant risk factor for Alzheimer’s disease. In order to investigate the relationship of Eichner index and Alzheimer’s disease, this study is conducted at 2018 in the Neurology Department of Imam Hossein Hospital and Department of Prosthodontics, Dentistry faculty, Tehran medical sciences, Islamic Azad University. Eichner index was evaluated and registered by an examiner

This study was conducted as case-control design. Diagnosis of Alzheimer’s disease was made based on MMSE test by the neurologist as single blind design using biting wax. In order to quantification of Eichner index, numbers of 0 to 7 were assigned to sub-indexes of C to A1. The quantified Eichner index was statistically evaluated using Mann–U-Whitney test.

The study was performed on 140 samples (70 in study group and 70 in control group). The age for study group was 75.9±18.5 year and 76.5±14.3 year for the control group, which were not statistically different (p>0.05). Eichner index values was 1.16±1.63 for the study group and 2.3±2.07 for the control group. Statistical test showed that the difference between the two groups is significant (p=0.01).

Within the limitations of this article, it seems that there is a statistically significant relationship between Eichner Index and Alzheimer's disease and decreasing of posterior supporting dental occlusion was presented more in Alzheimer's disease patients vs. normal population.

The purpose of this study was to evaluate the mechanical properties of flowable dental composites containing the antibacterial compound.

The study was conducted through experimental design. Compound 3- (2,5-Dimethylfuran-3-yl) -1H-pyrazol-5- (4H)-one were synthesized using Ethyl chloroformate, hydrazine hydrate and 3-acetyl-2,5-dimethylfuran. In this study we had six experimental groups consisting of five resin composites containing 3- (2,5- dimethylfuran -3-yl) -1H-pyrazole-5 (4H) -one in different concentrations of 1, 2, 3, 4, and 5 wt.% and one control group with no additive. They were prepared by high speed mixer at room temperature and under normal conditions for humidity and temperature, using standard 4049 compressive strength tests. Their diametral tensile and flextural strength were evaluated.

With increasing percentage of antibacterial compound The flexural strength decreased but this difference was not significant between the 1% and control groups.(p>0.05) The results of diametral tensile strength showed that there was no significant difference between the control group and 1% but the compressive strength significantly decrease by increasing the percentage of compound 3- (2,5- dimethylfuran -3-yl) -1H-pyrazole-5 (4H) -one.(p<0.05)

The combination of antibacterial component, although leads to an acceptable increase in the antibacterial properties of flowable dental composites and in Their flextural and tensile strengths had no effect, but a significant decrease in their compressive strengths, which could limit their use.

Dental anxiety is one of the important reasons for avoiding dental treatment and, in the long time it can result in decrease in oral and dental health as well as decrease in quality of life of patients. Furthermore, the presence of anxiety in the patients and its repetition in the examination of patients can also affect the efficiency of dentists. The aim of this study was to investigate the effect of verbal education on the anxiety of patients with irreversible pulpitis

In this clinical trial, 96 patients with irreversible pulpitis of maxillary premolars referred to Khatam-ol-Anbia Specialty Clinic in Yazd, Iran were randomly studied into case and control groups. Before the start of the treatment, a verbal description of the therapeutic measures and type of devices was given to the case group patients for 15 minutes, but no verbal education was given to the control group. Patients completed the Standard Dental Anxiety Scale (DAS). The data were statistically analyzed using SPSS17 software and T-test and paired T-test.

Before the intervention, the anxiety score in the control group was 10.46 and in the intervention group was 11.71 (p > 0.05), and after the intervention, it was 8.65 and 8.21 respectively (p > 0.05). The rate of anxiety reduction in the intervention group was significantly more than the control group (p =0.017).

The reduction in anxiety score in the intervention group was significantly more than the control group, which was the result of intervention and it can be said that the verbal explanation was effective in reducing the anxiety of the patients.

 The prevalence of avulsed teeth is high and wrong treatment can complicate dental problems, so emergency treatment and making the right decision is crucial. This study was going to assess knowledge of general dentists regarding this issue in order to proper orientation in future education.

This descriptive-cross sectional research was done on 300 dentists who have participated in operative and oral disease congress in 2018.Volunteers answered to 11 multiple choice questions in 4 stages of very good, good, fair, poor. Dentists whose grade were in range of very good to good were considered as acceptable score. Dentists whose grade were in range of fair to poor, they were considered as unacceptable score. Findings were evaluated by chi-square analysis.

 From 300 dentists who were tested, 33% of them had acceptable point and 67% had unacceptable point. The most difficulty they had was knowing the appropriate time to start root canal treatment in mature teeth (76/7%). Insufficient knowledge was significantly higher in more experienced dentist (P=0/003) and dentists who had no experience about treatment of traumatic teeth (P < 0/00).

  It seems the amount of knowledge for treatment of avulsed teeth is low and concerning among general dentists especially those graduated from university for a long time ago, the amount of knowledge is decreased.

 Oral Submucous Fibrosis (OSF) is an oral premalignant condition with highest premalignant potential  among oral precancerous lesions which characterized with inflammation and  progressive fibrosis of  submucosal oral tissues (cause to significant irreversible rigidity and trismus). During the years, many classification systems have been proposed  in medicine literatures  on basis clinical, functional and  histopathological  aspects.This review study was done with aim of  assessment and presentation of proper classification systems to the physicians  use  in therapeutic centers  for early diagnosis, disease progression and proper treatment plan for OSF patients.

Research was done in pubmed, Google scholar, science direct, web of sciences and Scopus databases and totally ,30 articles were selected.

The study resulted in a new and appropriate classification system covering all aspects of the disease including clinical, functional, histological, treatment and prognosis. Also pathogenesis and  new management of OSF  have been discussed.

  Attempts to provide and update the knowledge of Submucous fibrosis classification system to assist clinicians, can be useful in researches and classifying this potentially malignant disease and help greatly in the early diagnosis, proper management and reduction of morbidity and mortality of the disease.

 Keratinized odontogenic cyst is a developmental odontogenic cyst that is mainly due to dental lamina. This cyst has the nature of local invasion and high recurrence. There are several therapeutic measures to control the recurrence of this cyst in studies. One of the conservative approaches is to use an enucleation followed by decompression techniques. The aim of this study was evaluation of the combined therapeutic approach of decompression and enucleation with 3 years follow up as the definite treatment.
Case Report: Case study is a 5-year-old male patient with left mandibular OKC who has been definitively treated with decompression and enucleation with peripheral ostectomy and use of 5FU (5 flurouracil) topical ointment.

Despite many options for OKC treatment, surgeons often seek conservative treatment of this cyst by decompression and enucleation because morbidity and recurrence are less reported than other methods.