Hülya Erten

The Resistance of Collagen-associated, Planktonic Cells of Enterococcus faecalis to Calcium Hydroxide

This study examined whether collagen association by an endodontic isolate of Enterococcus faecalis conferred resistance to the bacterium against calcium hydroxide. E. faecalis A197A was grown at 46 degrees C until early stationary phase. Standardized bacterial suspensions were pretreated for 1 hour either with acid-soluble collagen or acidified phosphate-buffered saline (ac-PBS) and cultured to determine the baseline viable bacterial numbers. The bacterial suspensions were challenged with calcium hydroxide solution. Samples were removed at 6, 12, and 24 hours and cultured on tryptone soy agar plates. An adherence assay was performed to confirm that the collagen in the pretreatment medium was bound by the bacteria. Significantly more bacteria were cultivated at 12 hours in the collagen-pretreated group than the ac-PBS-pretreated group (p < 0.01). No bacteria could be cultivated at 24 hours in either group. Collagen association by E. faecalis A197A was found to increase the tolerance of the bacterium to calcium hydroxide.

Reliability and validity of the Turkish version of the shorter form of the gagging problem assessment questionnaire

The aim of this study was to evaluate the reliability and validity of the Turkish version of the shorter form of the gagging problem assessment questionnaire. Forty-three patients with gagging problems and 89 patients who showed no signs of gagging during dental examination were included in the study. The patients completed the patient portion of the gagging problem assessment questionnaire, as well as the modified dental anxiety scale, dental fear scale and Spielberger trait anxiety scale for comparison. Two experienced dentists subsequently completed the dentist portion of the gagging problem assessment questionnaire by performing clinical examinations with a dental mirror. The results indicate that patients with gagging problems had significantly higher mean scores than the control group (P < 0.001). The internal consistency of the questionnaire was found to be adequate, and good intra- and inter-observer reliability was present. Patients with a gagging reflex had significantly higher anxiety scores, indicating the validity of the questionnaire. The Turkish translation of the shorter form of the gagging problem assessment questionnaire was found to be reliable and valid for distinguishing among patients with and without a gagging reflex.

Possible role of the adhesin ace and collagen adherence in conveying resistance to disinfectants on Enterococcus faecalis

INTRODUCTION This study aimed to evaluate whether the presence of the ace gene and Ace-mediated binding to collagen confers on Enterococcus faecalis resistance against common endodontic disinfectants. METHODS Isogenic strains of E. faecalis: OG1RF (wild-type) and TX5256 (ace insertion mutant of OG1RF) were grown in brain-heart infusion broth at 46 degrees C overnight. Standardized bacterial suspensions were pretreated for 1 h either with acid-soluble collagen or acidified phosphate-buffered saline (ac-PBS). Bacteria were challenged with chlorhexidine digluconate (CHX), iodine potassium-iodide (IKI), sodium hypochlorite (NaOCl), and calcium hydroxide [Ca(OH)(2)]. Samples were removed at 1, 3, and 6 h, and cultured on Todd-Hewitt agar plates. Colonies were counted, the absolute values were log transformed, and the data were statistically analyzed using Fishers least significant differences test and t-test. RESULTS OG1RF was more resistant than TX5256 to IKI, NaOCl, and Ca(OH)(2) (P < 0.05). Collagen-exposed OG1RF was more resistant than the ac-PBS-pretreated OG1RF against CHX at 3 h and against IKI at 1 h (P < 0.05); no significant difference was found against NaOCl. As expected, the ace mutant strain, TX5256, pretreated with collagen or ac-PBS did not differ significantly in viability when challenged with CHX, IKI, and NaOCl. An unexpected result was found for Ca(OH)(2): collagen-pretreated OG1RF and TX5256 were both more susceptible than ac-PBS-pretreated OG1RF and TX5256, respectively (P < 0.05). CONCLUSION The presence of the ace gene confers resistance against IKI, NaOCl, and Ca(OH)(2) on E. faecalis. Exposure to collagen makes the wild-type bacterium more resistant against CHX and IKI; however, exposure to collagen apparently decreases resistance to Ca(OH)(2).

Oxidative stress and cellular immunity in patients with recurrent aphthous ulcers

Recurrent aphthous ulcer (RAU) is an inflammatory condition of the oral mucosa characterized by painful, well-circumscribed, single or multiple round or ovoid ulcerations. The exact etiologic factor(s) of these ulcerations are not yet understood. The objective of this study was to evaluate inflammatory processes and free radical metabolism of 25 patients with RAUs compared to 25 healthy controls. The levels of malondialdehyde (MDA) and glutathione (GSH) were determined by high-performance liquid chromatography. Tumor necrosis factor-alpha (TNF-α), interleukin-2 (IL-2), IL-10, and IL-12 were determined by ELISA. Nitric oxide (NO), myeloperoxidase (MPO), total antioxidant status (TAS), and total oxidant status (TOS) levels were measured spectroscopically in serum. The levels of MDA, GSH, TNF-α, IL-2, IL-12, MPO, and TOS, and oxidative stress index (OSI) were higher, and the levels of NO, IL-10, and TAS were lower in patients with RAU than in controls. Statistical analysis showed that GSH, TNF-α, IL-2, IL-10, and OSI differed significantly in patients with RAU compared to controls. These parameters have important roles in oxidant/antioxidant defense.

Evaluation of the biocompatibility of experimentally manufactured portland cement: an animal study

Objectives: The purpose of this study was to evaluate the biocompatibility of MTA and the experimentally manufactured portland cement (EMPC). Study design: Twenty one Sprague Dawley (SD) rats were allocated to testing of three groups. Group I and Group II included ProRoot MTA and the EMPC. The materials were mixed with distilled water and placed in polyethylene tubes. The tubes were implanted subcutaneously in the dorsal region of the animals. Group III served as control; the implanted polyethylene tubes remained empty. At 7, 14, and 28 days after the implantation, the animals were sacrificed and the implants were removed with the surrounding tissues. The specimens were prepared for histological examination to evaluate the inflammatory response. Results: No significant difference was found between tissue reactions against the tested materials (p>0.05). Also, control group showed similar results (p>0.05). Conclusions: Results suggest that the EMPC has the potential to be used in clinical conditions in which ProRoot MTA is indicated. MTA and the EMPC show comparable biocompatibility when evaluated in vivo. Although the results are supportive for the EMPC, more studies are required before the safe clinical use of the EMPC. Key words:Mineral trioxide aggregate, portland cement, subcutanous implantation.

The Use of a Microscope for Restorative Treatment Decision-making on Occlusal Surfaces

Using an operating microscope, this study assessed the effect of 16x magnification on the restorative treatment of posterior teeth and compared the results against an unaided visual examination in vitro. Three dentists examined 300 premolars and molars at different times using an unaided visual examination and an operating microscope at 16x magnification. The observers examined the occlusal surfaces of teeth according to a patient model and selected a treatment protocol based on the following scale: 0: No Active Care (NC); 1: Preventive Care (PC) and 2: Operative Care and Preventive Care (OC+PC) advised. According to the results, there was good intra-observer agreement and moderate interobserver agreement with both techniques. No significant difference was found between the treatment using an unaided visual examination and that using an operating microscope. The use of a microscope at 16x magnification did not aid in the restorative treatment decision-making on occlusal surfaces.

A fatty tissue lesion of the floor of the mouth mimicking an odontogenic lesion

The floor of the mouth is a rare location for fatty tissue lesions. These lesions could cause resorption of the adjacent bone and lead to a radiolucent appearance on radiographs. In this case report, a non-capsulated lesion composed of mature adipose tissue located on the floor of the mouth causing a well-circumscribed oval radiolucent lesion close to the roots of the molar teeth due to resorption of mandible in a 33-year-old woman is reported.