Journal of Dental Research, Dental Clinics, Dental Prospects
Volume:7 Issue: 3, Summer 2013

Bonding to dentin is a promising property, which can prevent leakage and improve the sealing ability of endodontic filling materials. Resilon was developed and recommended initially because the existing root canal filling materials did not bond to root canal dentin. Since its introduction in 2004, numerous reports have been published regarding various aspects of this material. This article aimed to review existing literature on Resilon’s physical and chemical properties as well as leakage studies. Articles on Resilon were collected using electronic and hand searching methods from May 2004 to April 2012. Having some antibacterial and antifungal properties, it is a promising material for root canal filling. Despite the presence of numerous case reports and case series regarding its applications, there are few designed research studies on clinical applications of this material.

The aim of this study was to determine the stress patterns within an implant and the effect of different types of connections on load transfer. Three different types of implant-abutment connections were selected for this study. Sample A: 1.5-mm deep internal hex corresponding to a lead-in bevel; sample B: a tri-channel internal connection; and sample C: in-ternal Morse taper with 110 degrees of tapering and 6 anti-rotational grooves. Four types of loading conditions were simu-lated in a finite element model, with the maximum von Mises stress set as output variables. The maximum stress concentration at the inner surface of the fixtures was higher than the stress value in bone in all of the samples. Stress values in sample B were the lowest amongst all of the models. Any alterations in the amount and direction of the 100-N axial load resulted in an increase in fixture surfaces stress. Overall, the highest amount of stress (112 MPa) was detected in sample C at the inner surface of the fixture under a non-axial load of 300 N. Stress concentration decreased when the internal surface area increased. Creating three or six stops in the internal surface of the fixtures resulted in a decrease in stress.

Current chemical methods may not efficiently disinfect dental stone casts. The aim of this study was to investigate if microwave irradiation is effective for disinfection of stone casts. In this laboratory study, three groups (n = 162) of prepared spherical stone beads as carriers with a diameter of 10 mm were inoculated by separately soaking in three broth culture media, each containing a study microorganism—Pseudomonas aeruginosa, Staphylococcus aureus or Candida albicans. Six inoculated carriers were used for every test, including irradiation in a household microwave oven at 300, 450, 600 or 900 W energy level, or soaking in 0.03%, 0.06%, 0.12%, 0.25% or 0.50% concentration of sodium hypochlorite solution, at 1, 2, or 3-minute test times. Positive and negative control groups were considered for each test. All treated carriers were then individually transferred to nutrient broth culture medium and one milliliter from each tube was cultured in nutrient agar media over night. Colony forming unit per milliliter (CFU/mL) was counted, and multi-factor ANOVA was used to analyze data (α = 0.05). Microwave irradiation at 600 W resulted in high-level disinfection in 3 minutes. Immersion of the stone casts in hypochlorite solution at 0.06% concentration resulted in disinfection after 2 minutes. According to the results, high level disinfection of the stone casts can be achieved by microwave irradiation at 600 W in 3 minutes, similar to a validated chemical method.

Espar is a dairy product of probiotic nature that contains useful bacteria and high calcium con-tent. The aim of this study was to analyze effects of daily consumption of Espar on the number of salivary mutans strepto-cocci and the level of calcium content in a population of 15 to 17 year-old female students. A double-blind randomized crossover study (n = 50) of healthy female adolescents was im-plemented in four stage intervals. The first and third stages were ‘run-in’ and ‘wash-out’ intervals. For the second and fourth stages, two weeks long in duration, the participants consumed 100 grams of Espar or 200 grams of plain yogurt. At the end of each stage, the number of salivary mutans streptococci and the level of calcium content were documented. There was a statistically significant decrease in the number of salivary mutans streptococci subsequent to Espar consumption when compared to ordinary yogurt (p < 0.01). Additionally, salivary calcium content increased significantly subsequent to the consumption of Espar and yogurt. However, Espar yielded a higher level of significant increase in sali-vary calcium when compared to plain yogurt (p < 0.01). This study found that daily consumption of Espar increased the salivary calcium level while decreasing mu-tans streptococci of the saliva.

We aimed to assess the bond strength of composite resin to three pulp capping biomaterials; ProRoot mineral trioxide aggregate (PMTA), Root MTA (RMTA) and calcium enriched mixture (CEM), using three bonding systems [a total etch (Single Bond) and two self-etch systems (Protect bond and SE Bond)]. Ninety acrylic moulds containing a 6×2 mm hole were divided into 3 groups and were filled with PMTA, RMTA and CEM. The samples were then randomly divided into 3 subgroups; Single Bond, Protect Bond and SE Bond bonding systems were applied to the tested materials. Cylindrical forms of composite resin (Z100, 2×2 mm) were placed onto the samples and cured. Shear bond strength values were measured using a universal testing machine. Data were analyzed using Two-way ANOVA test. The average shear bond strengths of Z100 composite resin after application of Single Bond, Protect Bond and SE Bond systems were as follows; PMTA: 5.1±2.42, 4.56±1.96, 4.52±1.7, RMTA: 4.71±1.77, 4.31±0.56, 4.79±1.88 and CEM: 4.75±1.1, 4.54±1.59, 4.64±1.78 megapascals respectively. The type of pulp capping material, bonding system and their interacting effects did not have a significant effect on the bond strengths of composite resin to pulp capping biomaterials. Within the limitations of this in vitro study, bond strength of composite resin to two types of MTA as well as CEM cement were similar following application of the total etch or self-etch bonding systems.

In various clinical situations, mineral trioxide aggregate (MTA) may come into direct contact with blood. The aim of the present study was to evaluate the effect of exposure to blood on marginal adaptation and surface microstructure of MTA. Thirty extracted human single-rooted teeth were used in this study. Standard root canal treatment was carried out. Root-ends were resected, and retrocavities were prepared. The teeth were randomly divided into the following two groups (n=15): In group 1, the internal surface of the cavities was coated with blood. Then, the cavities were filled with MTA. The roots were immersed in molds containing fresh blood. In group 2, the aforementioned procedures were performed except that synthetic tissue fluid (STF) was used instead of fresh blood. After incubation, the specimens were prepared for scanning electron microscopic analysis. To assess the marginal adaptation, “gap perimeter” and “maximum gap width” were measured, respectively. The surface microstructure was also examined at higher magnifications. Independent samples t-test and Mann-Whitney U test were used to analyze data. Maximum gap width and gap perimeter in the blood-exposed group were significantly larger than those in the STF-exposed group (p)

Present study was designed to compare the bonding strength of resin-modified glass ionomer (RMGI) and composite resin to mineral trioxide aggregate (MTA), MTA mixed with Na2HPO4 (NAMTA), and calcium-enriched mixture (CEM). Thirty specimens of each CEM, NAMTA, and MTA were prepared. Composite and RMGI restorations were then placed on the samples (15 samples in six subgroups). Shear bond strength was assessed using universal testing machine. Data were analyzed with two-way ANOVA and post-hoc Tukey test. To compare the bond strength in subgroups, one-away ANOVA was applied. Significance level was set at P < 0.05. Bond strength was significantly higher to composite samples compared to RMGI samples (p0.05). Regarding shear bond strength to the tested substrates, composite was shown to be superior to RMGI. The bond of resin composite to MTA was weaker than that to CEM and NAMTA.

Oral cavity provides variety of surfaces for bacterial attachment and colonization. These bacteria can enter the circulatory system of the human body and become pathogenic. Thus chronic oral inflammations are regarded as a potent risk factor for systemic pathologies. According to literature classic risk factors only can explain half to two thirds of cardiovascular diseases and is believed that those with the worst oral health status are more susceptible to cardiovascular disease. Since in electrocardiograph changes in ST segment and serum CRP level are predictive of poor patient outcome, in this study the aim was to evaluate the possible relation between electrocardiograph ST segment changes, serum CRP level with oral health in determining the severity of cardiovascular disease. Method & materials: In this cross sectional study, thirty six patients with myocardial infarction were enrolled. Oral health indices DMFT,PPD,CAL and BOP were compared with serum C-reactive protein level and electrocardiograph ST segment changes. No statistically significant difference between PPD,BOP,CAL with serum CRP level was seen although a statistically significant difference was observed between CRP and DMFT. BOP and PPD revealed no statistically significant difference between two ST segment groups. Although CAL and number of fillings showed a statistically significant difference within ST segment groups. As results of this study shows it can be concluded that poor oral health may be linked to systemic pathologies but it cannot be a predictor of prognosis. Similar studies with more sample size is strongly recommended.

Evaluation of enlarged follicles with unerupted teeth is always important because some changes may occur. One of the extremely rare conditions seen in dental follicles is multiple calcifying hyperplastic dental follicle. We report a case of multiple calcifying hyperplastic dental follicle. Radiographs showed that mandibular third molars had a pericoronal radiolucent zone delineated by a well-defined and sclerotic border. Microscopic examination revealed a combination of fibrous connective and small calcifications. Multiple calcifying hyperplastic dental follicle is a rare condition and its correct diagnosis is necessary to apply appropriate treatment.

Osteosarcoma (OS) is a malignant mesenchymal tumor، which rarely occurs in the maxilla. Although variable histologic and radiographic features of OS have been reported previously، in the majority of the cases painful swelling of the jaw is mentioned as the first clinical presentation. Furthermore، early diagnosis and wide surgical resection of the tumor are the most important determinant factors of prognosis. Therefore، the unusual clinical presentations of OS should be considered meticulously to expedite the diagnosis process. We describe a case of OS of the maxilla with extremely unusual presenta-tion in a 42-year-old female، that was initially designated as “epulis fissuratum”. Here، we highlight the importance of com-bining the clinical، radiographic and histopathologic examination to obtain a definitive diagnosis and also the significance of early effective surgical intervention in evaluation of pathologic lesions.