Journal of Dental Medicine

Normal 0 false false false EN-US X-NONE AR-SA Buccal surface of Extracted permanent teeth was divided into two parts and etched by 30, 37, 50 and 60% concentrations of phosphoric acid gel and solution. Sealant replica was obtained from the etched surfaces of 50% gel and solution and the samples were examined by scanning electron microscope (SEM). Various views were found on replica. Gels are more effective than solutions and the concentration of 37-40% was found the most efficient one for acid-etching.

Wear characteristics of dental amalgams were investigated by in vivo and in vitro tests. Wear of dental amalgam was studied and evaluated using a three - body abrasion test and Pin-On-Disk method. Porcelain was used for preparing disk and materials such as toothpaste, artificial saliva and naturally saliva were used as the third material that was contributed in tribologic system The results showed that effects of various toothpastes on the wear of dental amalgam are considerably different and size, shape and chemical composition of amalgam are important too.

Characterization of bioceramics coating and evaluation of the influence of kind of coating on the implantation has been developed in recent years.Different bioceramics coating like calcium phosphate, hydroxyapatite, fluorapatite and bioglass were coated on dental and orthopedic implants. In-vitro and in-vivo experiments were done for evolution of implant success and reliability and study of factors, which may influence the results.Researches indicate that different bioceramic coating may affect the bone bonding mechanism.Biodegredable calcium phosphate coating can be resorbed and be replaced with bone tissues.Hydroxyapatite cause earlier stabilization of dental implant in surrounding bone (biological fixation) and reduce healing time. Bioglass can protect substrate and provide interfacial attachment to bone.

Dental enamel is the end product of amelogenesis, which can be considered to take place in three interrelated phases. When this complex sequence of cytological and physicochemica! events disrupted by genetic or environmental factors, the function of the ameloblasts may be disrupted permanently or temporarily. The result shows qualitative and quantitative defects that may range from a complete absence of enamel or a slight discoloration. The aim of this study was to determine the prevalence of enamel defects by DDE index in a randomly selection group of 1637 students age 7-12 years old in Isfahan (0.2-0.3 PPMF"). Enamel defects were present on one or more teeth in 27% of the cases. The most common affected tooth was the central maxillary and then first molar of maxilla. The most common affected surfaces were buccal. Hypoplastic defects were found in first molar however premolar and canine were affected by diffuse white lines opacity.

Nowadays, application of implants as a new method for replacing extracted teeth have been improved. So, many researches have been performed for improving the characteristics of implants. The aim of this study was to design and produce a desired coating in order to obtaining two goals including improvement of the corrosion behavior of metallic endodontic implant and the bone osseointegration simultaneously. Stainless steel 316L (SS), cobalt-chromium alloy (Vit) and commercial pure titanium (cpTi) were chosen as metallic substrates and hydroxyapatite coating (HAC) were performed by plasma-spraying (PS) process on three different substrates. A novel double layer Hydroxyapatite/Titanium (HA/Ti) composite coating composed of a HA top layer and a Ti under layer was prepared using PS and physical vapor deposition (PVD) process respectively on SS. Structural characterization techniques including XRD, SEM and EDX were utilized to investigate the microstructure, morpholgy and crystallinity of the coatings. Electrochemical potentiodynamic tests were performed in physiological solutions in order to determine and compare the corrosion behavior of the coated and uncoated specimens behavior as an indication of biocmpatibility. Results indicated that the cpTi possesses the highest and SS the lowest corrosion resistance (highest corrosion current density) between uncoated substrates. This trend was independent to the type of physiological environment. The HA coating decreased the corrosion current density of HA coated metallic implants but did not change that trend. HAC acted as a mechanical barrier on the metallic substrate but could not prevent the interaction between metallic substrate and environment completely. The HA/Ti composite coating improved the corrosion behavior of SS. The corrosion current density of HA/Ti coated SS decreased and was exactly similar to single HA coated cpTi in physiological solutions. The results indicated that HA/Ti composite coated SS could be used as an endodontic implant and two goals including improvement of corrosion resistance (biocompatibiiity) and bone osseointegration could be obtained simultaneously.

Statement of Problem: Microleakage presents the major cause for restorations failure in the oral cavity resulting in postoperative sensitivity, pulp irritation and secondary caries formation.

Aim: The aim of this study was to compare two dentinal adhesive systems of fifth generation and copalite varnish in reducing microleakage of amalgam restorations in primary teeth.
Materials and Methods: In this in-vitro study, 100 class V amalgam restorations were prepared on the buccal or lingual surfaces of primary molar and canine teeth. Samples were randomly divided into four groups (25 samples each). No liner was used for the first group and the second group restorations were lined with copalite varnish. Two dentin adhesives, called Syntac C and Single Bond, were used for the third and fourth groups, respectively. At the next stage, the samples were immersed in 5% fuschin solution for 24 hours, then sectioned buccolingually, and examined under a stereomicroscope for microleakage evaluation.
Results: There was a significant difference between four groups statistically (PO.000I), Comparing four groups, the first and fourth ones, demonstrated the most and the least microleakage, respectively.

Conclusion: The present study showed that new dentinal adhesive systems caused microleakage reduction in amalgam restorations of primary teeth.

Statement of Problem: Blood contamination is a common problem in dentistry that can decrease bond strength dramatically which may be affected by methods of decontamination as well.

Purpose: The aim of this study was to evaluate and compare the influence of blood contamination on shear bond strength of composite and compomer to dentin using Prompt L-Pop as an adhesive system. Also, to assess the effectiveness of different surface treatments on the bond strength.

Materials and Methods: In this experimental study, 120 molar teeth were sectioned to provide flat occlusal dentinal surfaces. Specimens were embedded in acrylic resin with the flat surface exposed. The dentinal expose surfaces were polished to 600 grit. The teeth were randomly divided into five groups of twelve specimens (F1–F5) for compomer material and five other groups (Z1- Z5) for composite resin. After application of Promt L-Pop to dentinal surfaces of specimens, the surfaces in all groups, except for F1 and Z1, (as controls) were contaminated with human blood and then one of the following surface treatments was applied. Groups F2 and Z2 without any treatment, groups F3 and Z3 rinsing with water, groups F4 and Z4 rinsing with water and reapplication of adhesive, groups F5 and Z5 rinsing with NaOCl and using Prompt L-Pop again. Restorative materials were applied to treated surfaces using plastic molds. After thermocycling, shear bond strengths, mode of failures and morphology of dentin-material interfaces were evaluated. The data were statistically analyzed using Factorial analysis of Variance, One-Way ANOVA, Duncan, T-student and Chi-Square tests with P<0.05 as the limit of significance.

Results: Compomer showed statistically significant higher bond strength in comparison to composite (P<0.001). Duncan test showed significant differences between all compomer groups, except between groups F4 and F5, and between all composite groups except for groups Z1 and Z4 and for groups Z2 and Z3.

Conclusion: Based on the findings of this study, shear bond strength of compomer material was significantly higher than composite. Blood contamination reduced bond strength, but rinsing contaminated dentin with water or NaOCl and reusing Prompt L-Pop increased bond strength in both materials.

Background and Aim: Although the use of adhesive systems can be effective in decreasing microleakge, it is still a major problem in composite resin restorations. The aim of the present study was to evaluate the marginal sealing ability of resin composite restorations using four dentin bonding systems in both primary and permanent teeth.

Materials and Methods: In this experimental study, one hundred and sixty extracted human teeth (80 primary and 80 permanent) were selected. All of the samples received a class V cavity preparation on the buccal surfaces (The coronal half in enamel and the gingival half in cementum or dentin). Each group was then divided into four subgroups each containing 20 teeth. Four different dentin bonding systems (Scotchbond Multipurpose, Single Bond, Clearfil SE Bond and Prompt L-Pop) were used in each subgroup. Then the cavities were filled with composite resin (Z100 for SBMP and Clearfil AP-X for Clearfil SE Bond). Samples were thermocycled, immersed in 0.5% basic fuschin, cut faciolingually and evaluated for dye penetration using a binocular stereomicroscope. Kruskal-Wallis and Dunn tests were used for comparison of microleakage between groups with p<0.05 as the limit of significance.

Results: The results showed that: There was significant difference in microleakage among four adhesive systems in both incisal and gingival margins of permanent teeth and in incisal margin of primary teeth (P=0.000, P=0.002, P=0.000 respectively). There was no significant difference in microleakage of restorations with each of four systems between permanent and primary teeth in both incisal and gingival margins except for PLP, which showed a significant different microleakage in the cervical margins (P=0.009). PLP showed better cervical seal in primary teeth compared to permanent teeth. Clearfil SE Bond showed acceptable results at incisal and cervical margins in primary teeth in comparison to other bonding systems.

Conclusion: Based on the results of this study, CSEB, SB and SBMP systems showed acceptable clinical results in primary and permanent teeth. Only PLP showed weak results in reducing microleakage. CSEB can be used successfully in primary teeth because of simplicity and reducing leakage in primary dentin and enamel.

Background and Aim: According to controversies in the prevalence of hypersensitivity to dental local anesthetic drugs and patients who claim hypersensitivity to these drugs, the aim of this study was to determine the prevalence of hypersensitivity to dental amide local anesthetic drugs in patients referred to Tehran Allergy Clinic in 2005-2007.

Materials and Methods: In this Study (Review of existing data), records of 130 patients who were referred to "Tehran allergy Clinic" (2005-2007) were studied.

Results: The average age of patients was 29.5±18.8 years. 34% of cases showed positive skin reactions to at least one of the tested Lidocain concentrations and 10% of cases showed positive skin reactions to at least one of the tested Prilocain concentrations. There was a statistically significant difference in hypersensitivity to Lidocain 0.01 and 0.001 (p=0.017) and also between Lidocain 0.001 and 0.0001 (p<0.01). There was no statistically significant difference between other tested drug concentrations (p>0.05).

Conclusion: Many patients with history of hypersensitivity, show positive reaction to local dental anesthetic drugs. Prilocain hypersensitivity reactions are less than Lidocain. So application of Prilocain accompanies with less risk but its application should not be considered completely safe.

  Background and Aims: The purpose of the present study was to review the studies regarding serological and salivary oxidant / antioxidant status in patients with recurrent aphthous stomatitis (RAS).

  Materials and Methods: The literature was searched using key words RAS, Antioxidants, Saliva, Hematinic (s) and Hematinic Acid in the last 10 years, particularly the recent 3 years (2010-2013). At total of 37 clinical trials, 18 case-control articles were selected and evaluated fulfilling the requirements as the RAS patients having at least 3 oral aphthous attack per year. The exclusion criteria included systemic as well as periodontal diseases, iron deficiency associated anemia, medication usage and smoking.

  Conclusion: Almost all lipid-peroxidation studies in serum and saliva were manifested by an increase of malondialdehyde (MDA) concentration in RAS patients compared with controls. This would indicate the role of reactive oxygen species (ROS) in the etiology of the disease. Serum trace elements (Zn, Se) were reduced and Cu was increased in RAS patients in comparison with control individuals. A decreased serum superoxide dismutase (SOD) and an increased salivary SOD were observed in all RAS patients. Catalase (CAT) and uric acid (UA) analyses were non-inclusive. Levels of paraoxonase and arylesterase as well as antioxidant vitamins (A, E, C) were lower in RAS patients than that of controls.