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Biomedical subjects

F Koray

Publications and source records attributed to F Koray.

10 recordsLinked to original sources
PubMed2005

Effect of resin-based material combination on the compressive and the flexural strength.

The mechanical properties, elasticity and compressive strength, of restorative materials play a crucial role during mastication for clinical performance of materials in particular stress bearing areas at posterior regions. This in vitro study was objected to evaluate the changes in the compressive and flexural strength of tooth-coloured resin-based dental restorations placed on flowable composites. Specimens in the control group were produced in cylindrical form for testing compressive strength and in quadrangular prism form for flexural strength test. Tetric Ceram, Charisma, Surefil, Admira and two compomers; Dyract AP and Compoglass F in test group specimens were fabricated by placing the control materials on different flowables. The material combinations were as follows: Tetric Ceram/Tetric Flow Charisma/Flowline, Surefil/Dyract Flow, Admira/Admira Flow, Dyract AP/Dyract Flow, Compoglass F/Compoglass Flow. Compressive strength values were measured at the Instron Testing Machine with a cross-head speed of 10 mm min(-1) while flexural strength were determined in three-point bending with a cross-head speed of 1 mm min(-1). One-way anova and Tukey's multiple comparison tests were performed for the statistical analysis. The flexural strength values of Tetric Ceram/Tetric Flow (135.9 +/- 3.2), Charisma/Flowline (120.4 +/- 5.6) and Compoglass F/Compoglass Flow (108.2 +/- 5.2) combinations were statistically greater than Tetric Ceram (110.8 +/- 10.5), Charisma (95.3 +/- 5.3) and Compoglass F (86.9 +/- 4.9). The results of the present study support the idea that the placement of flowable composite as a liner under the resin-based composite restoratives increase the flexural strength.

Compomers↗
PubMed2004

A comparative study of two fissure sealants: a 2-year clinical follow-up.

The aim of the study was to compare the fluoride-containing fissure sealants (Helioseal F) with the conventional (Concise Light Cure White Sealant) fissure sealants in their retention and caries-prevention capabilities in young population. Sealant materials were applied by three dentists on 122 fissures of first and second molars in 59 adults, 18-20 years of age. One hundred and twenty-two non-carious and unsealed molar teeth were selected as controls. The teeth were assessed using the following criteria: 1 - fully retained (FR), 2 - partially lost (PL), 3 - totally lost (TL) and 4 - decayed (D). All teeth were clinically assessed at 3, 6, 12 and 24 months by two examiners who were blinded to the sealant materials. Data were statistically analysed with chi-square tests. After 3 months 72.1% of sealants were fully retained, at 24 months this had dropped to 46.7%. The partial loss of sealants was at 3 months (15.6%), 6 months (26.2%), 12 months (27.9%) and 24 months (27%). The total loss of Helioseal F (16.4, 19.7, 18, 23% at 3rd, 6th, 12th and 24th months, respectively) was more than the total loss of Concise Light Cure White Sealant (8.2, 9.8, 11.5, 18%, respectively); meaning that the retention rate of Helioseal F was lower than for Concise Light Cure White Sealant. No caries was detected at 3rd and 6th months in all sealant-treated teeth. The incidence of caries in Helioseal F treated teeth at 12 and 24 months was 11.5% and 0% in Concise Light Cure White Sealant treated teeth. The incidence of caries in all fissure-sealant-treated-teeth after 24 months was 5.7 and 25.4% in control group. The results underline that the application of fissure sealants to young people in this sample is an effective method for the prevention of fissure caries.

Adolescent↗
PubMed2001

Alstrom syndrome: a case report.

Alstrom syndrome is a rare disorder characterized by early obesity, loss of central vision, diabetes mellitus, hearing loss and short stature. Previous studies, have reported no information regarding oral findings. This article describes oral findings in two cases of Alstrom syndrome. In both cases, gingivitis was present and also light yellow-brown discolored enamel bands were observed on the anterior teeth. This staining may have resulted from discoloration of the preexisting slight band-like enamel hypoplasia. The gingiva was examined histologically by light and transmission electron microscopy. Irregular thickness of the basal lamina and delamination of the myelin sheath were detected by transmission electron microscopy. There is no information about pathological odontogenesis in Alstrom syndrome in previous reports. Oral present findings may contribute further information about the clinical manifestations of Alstrom syndrome.

Abnormalities, Multiple↗
PubMed2000

The relation between salivary IgA and caries in renal transplant patients.

OBJECTIVE: The purpose of this study was to evaluate the effect of immunosuppressive drugs on the level of salivary immunoglobulin A (IgA) in patients who have received kidney transplants and the relation between the levels of salivary IgA and dental caries incidence. STUDY DESIGN: Patients who had undergone renal transplantation (n = 28, aged 18-54) were divided into 3 groups according to postsurgical period (0-6 months [G(1)], 6-12 months [G(2)], and >12 months [G(3)]). A healthy control group (n = 10, aged 17-49) was also included in this study. Saliva samples were collected from all patients by the spitting method. After collection, the samples were frozen immediately at -40 degrees C until analysis by the single radial immunodiffusion method. All fissure caries were examined clinically, and proximal caries were examined clinically and radiographically; caries status was determined according to the decay surface index. The findings were evaluated statistically by means of correlation analysis, the Kolmogorov-Smirnov test, and the 1-way Kruskal Wallis analysis of variance method. RESULTS: Salivary IgA levels of the patients who had undergone renal transplantation were found to be significantly lower than those of the control patients (G(1) = 6.76 mg/dL, G(2) = 6.80 mg/dL, G(3) = 7.84 mg/dL, and control group = 10.84 mg/dL, P <.001). However, the caries status of the patients who had undergone renal transplantation was not different from that of the control subjects for the first year after the transplant operation. The salivary IgA values of the 3 groups of patients who had undergone transplantation were not significantly different from each other. Thus, it was observed that a decrease in the level of salivary IgA does not result in an increase in caries incidence within 12 months after renal transplantation. The caries rate in the third group of patients who had undergone renal transplantation was found to be significantly different from those in the first and second groups. CONCLUSION: Low salivary IgA levels caused by immunosuppression are not correlated or associated with higher levels of dental caries within the first 12 months after renal transplantation. However, the incidence of dental caries was higher for patients who had undergone renal transplantation than for control subjects 12 months after renal transplantation. Because of the diagnostic processes used, dental caries may not become evident until after 12 months.

Adolescent↗
PubMed1997

Monitoring the caries risk of orthodontic patients.

Several caries activity tests were used to investigate the caries risk of patients with fixed orthodontic appliances. Twenty young individuals, with a mean age of 11 years, participated in this study. Ten subjects were free of any orthodontic appliances and formed the control group. The other 10 individuals had been wearing fixed orthodontic appliances for at least 4 months. Stimulated saliva samples were obtained from all patients. Saliva samples were used to investigate the salivary flow rate, the salivary buffer capacity, and mutans streptococci and lactobacilli counts. The orthodontic patients exhibited a significant increase in salivary flow rate. Results of statistical analyses were nonsignificant in all other tests, suggesting that fixed orthodontic appliances are not the sole factor increasing the patient's caries risk during orthodontic treatment.

Child↗
PubMed1988

Investigation of the aetiopathogenesis of amelogenesis imperfecta through microscopic, submicroscopic and cytogenetic methods--a case report.

A case of hypomineralized type of amelogenesis imperfecta has been evaluated by using microscopic, submicroscopic and cytogenetic techniques. It has been observed that some of the enamel contained hydroxyapatite crystals and showed normal mineralization, but some others consisted of transparent, crystal plates of octacalcium phosphate, revealing that these enamel prisms have hypomature characteristics. Extra chromosomes which belong to D-autosomes were found in the culture obtained from the peripheral blood of the patient, suggesting that the patient has 15% hyperdiploids. It is suggested that the structural disorders in some of the enamel prisms resulted from alterations in the environmental conditions related to chromosome anomalies.

Adult↗