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Biomedical subjects

Nilgun Ozturk

Publications and source records attributed to Nilgun Ozturk.

12 recordsLinked to original sources
PubMed2006

Risk factors and perinatal outcomes associated with umbilical cord prolapse.

OBJECTIVE: To utilize infant outcomes and to identify risk factors associated with umbilical cord prolapse. MATERIALS AND METHODS: Birth records of 80 cases with umbilical cord prolapse and 800 randomly selected controls were reviewed retrospectively. Statistical analysis was performed using logistic regression models. RESULTS: Prolapse of the umbilical cord complicated 0.47% (n=80) of all deliveries included in the study (n=16,874). Multiparity was more common in patients with umbilical cord prolapse (63.8-49.4%, P=0.014). Umbilical cord prolapse occurred in breech presentation in six cases (7.5%) and in transverse presentation in three of the cases (3.8%). The occurrence of breech presentation among the control cases was 1.0% and of the transverse lie was 0.1% (P<0.001). Fetuses with umbilical cord prolapse had lower fetal weight; particularly, fetal weight less than 2,500 g was a significant risk factor (3-2.4%, P<0.001). We also found that spontaneous rupture of membranes (OR=8.93; 95%, CI=4.16-19.14), Bishop score greater than 8 (OR=5.48; 95%, CI=3.21-9.34), and polyhydramnios (OR=21.0; 95%, CI=11.4-38.7) were risk factors for umbilical cord prolapse. The newborns that were delivered after umbilical cord prolapse graded lower Apgar scores less than 7 at 5 min (6.3-1.4%, P=0.002). CONCLUSION: Abnormal fetal presentation, multiparity, low birth weight, prematurity, polyhydramnios, and spontaneous rupture of membranes, in particular with high Bishop scores, are risk factors for umbilical cord prolapse. Early amniotomy increases the variable decelerations and hence increases the rate of cesarean section because of fetal distress, but it may prevent pregnant women from umbilical cord prolapse, which has a high mortality rate. However, large randomized trials are needed to prove that early amniotomy decreases the incidences of umbilical cord prolapse.

Adult↗
PubMed2006

Attenuation of ethanol withdrawal syndrome by extract of Hypericum perforatum in Wistar rats.

The effects of Hypericum perforatum (St John's wort) on ethanol withdrawal syndrome have been investigated in ethanol-dependent rats. Adult male Wistar rats were subjects. Ethanol (7.2% v/v) was given to rats by a liquid diet for 15 days. Hypericum perforatum extract (HPE) (25-200 mg/kg) and saline were injected to rats intraperitoneally just before ethanol withdrawal. After second, fourth and sixth hour of ethanol withdrawal, rats were observed for 5 min, and withdrawal signs that included locomotor hyperactivity, stereotyped behavior and tremors were recorded or rated. A second series of injections was given at 6 h after the first one, and subjects were then tested for audiogenic seizures. HPE (25-200 mg/kg) produced some dose-dependent and significant inhibitory effects on locomotor hyperactivity at second and sixth hour of ethanol withdrawal. In addition, it significantly reduced the number of stereotyped behaviors at the same dose range. HPE (50 and 100 mg/kg) produced some significant inhibitory effects on tremor and audiogenic seizures during withdrawal period. These results suggest that HPE has some beneficial effects on ethanol withdrawal syndrome in rats.

Animals↗
PubMed2005

Pulpal temperature rise during light-activated bleaching.

The purpose of this study was to measure intrapulpal temperature rise induced by two kinds of bleaching gels when the tooth was exposed to a variety of light-curing units and a diode laser in vitro. The root portions of 80 extracted intact human maxillary central incisors were sectioned with a carborundum disk approximately 2 mm below the cementoenamel junction perpendicular to the long axis of the teeth. Two bleaching agents containing heat-enhancing colorant was applied to the labial surface. Light-curing units used were a conventional halogen (40 s), a high-intensity halogen (30 s), a light-emitting diode unit (40 s), and a diode laser (15 s). The temperature rise was measured in the pulpal chamber with a J-type thermocouple wire that was connected to a data logger. Ten specimens were used for each system and bleaching-agent combination. Differences between the starting temperature and highest temperature reading were taken and the calculated temperature changes were averaged to determine the mean value in temperature rise. Temperature rise values were compared using two-way analysis of variance (ANOVA) at a preset alpha of 0.05. Temperature rise varied significantly depending on curing unit and diode laser used. The diode laser induced significantly higher temperature increases than any other curing unit (11.7 degrees C). The light-emitting diode unit produced the lowest temperature changes (6.0 degrees C); however, there were no statistically significant differences among the curing units and there were no statistically significant differences between bleaching agents. Light activation of bleaching materials with diode laser caused higher temperature changes as compared to other curing units and the temperature rise detected was viewed as critical for pulpal health.

Dental Pulp↗
PubMed2004

Microleakage of endodontically treated teeth with different dowel systems.

STATEMENT OF PROBLEM: Several new esthetic dowel systems are available for the restoration of endodontically treated teeth, but little is known about how effectively these dowels seal the restored teeth. PURPOSE: The purpose of this in vitro study was to compare microleakage of 3 esthetic, adhesively luted dowel systems with a conventional dowel system. MATERIAL AND METHODS: The root canals of 41 human intact single-rooted extracted teeth were prepared using a step-back technique. The teeth were randomly divided into 4 experimental groups (n=10), and 1 tooth served as a positive control. The decoronated roots were obturated with gutta-percha using lateral condensation. Roots were restored with 1 of the following dowel systems according to the manufacturer's instructions: (1) stainless steel dowels (ParaPost), (2) glass fiber dowels (Snowpost), (3) resin-supported polyethylene fiber (Ribbond) dowels, or (4) zirconia dowels (Cosmopost). Using a fluid filtration method, coronal leakage of the specimens along the dowel space and root canal restorative material was measured. Fluid movement measurements were made at 2-minute intervals for 8 minutes to measure the presence of voids existing in the obturated canals, at 1 week, 3 months, and 6 months following dowel insertion. A repeated-measures analysis of variance (ANOVA) was used to analyze logarithmic transformations of data (time and dowel material) for significant differences. The Tukey HSD test and paired 2-tailed tests were used to perform multiple comparisons (alpha=.05). RESULTS: The data indicated that the leakage values varied according to the dowel system used (P<.01). There was significant interaction between dowel systems and time of testing (P<.01). The sealing ability of zirconia dowels decreased over time (P<.01), but sealing abilities of stainless steel and resin-supported polyethylene fiber dowels remained constant (P>.05). The sealing ability of glass fiber dowels increased at 3 months (P=.032) and remained constant over the next 3 months (P=.758). Statistically, resin-supported polyethylene fiber and glass fiber dowels showed the lowest coronal leakage when compared with stainless steel and zirconia dowels at all time periods (P<.01). There were no significant differences between resin-supported polyethylene fiber and glass fiber dowels at any time period. The initial leakage measurement in zirconia dowel and stainless steel dowels were similar (P=.914), but became significantly different at 3 and 6 months (P<.01). CONCLUSION: Resin-supported polyethylene fiber dowels and glass fiber dowels tested exhibited less microleakage compared to zirconia dowel systems. The latter system should be further evaluated because of its unacceptable level of leakage.

Acrylic Resins↗
PubMed2004

An interdisciplinary approach for restoring function and esthetics in a patient with amelogenesis imperfecta and malocclusion: a clinical report.

This clinical report describes an interdisciplinary approach for the coordinated treatment of a patient diagnosed with amelogenesis imperfecta and malocclusion. The patient's functional and esthetic expectations were successfully met with interdisciplinary treatments, including orthodontics, porcelain laminate veneers, metal-ceramic fixed partial dentures, and direct composite restorations.

Adult↗
PubMed2004

Unsucessful labour induction in women with unfavourable cervical scores: predictors and management.

BACKGROUND: Misoprostol fails to induce labour in 5-20% of women at term. AIM: To analyse possible predictors of unsuccessful induction with 50 microg vaginal misoprostol and effectiveness and the safety of intracervical Foley catheter application in induction failures. METHODS: An observational study was conducted on 1030 women with singleton, live fetuses, vertex presentation, > 34 weeks of gestation and Bishop score < 5. Induction of labour with 50 microg vaginal misoprostol repeated every 6 h was attempted. Women without regular uterine contractions and cervical changes at the end of 24 h were considered to be unsuccessful, and a transcervical Foley balloon catheter was placed and inflated with 50 mL saline. Possible predictors of induction failures were analysed via logistic regression analysis. Neonatal outcomes and vaginal delivery achieved after Foley catheter were also determined. RESULTS: Induction was successful in 918 cases (89.1%) and Foley catheter was placed in 112 (10.8%) women. Increasing gestational age in weeks (odds ratio [OR] 0.77, 95% confidence interval [CI] 0.68-0.88) and increasing Bishop score (OR 0.73, 95% CI 0.60-0.90) decreased the risk of failed induction. Failure rates were 16% (27/169) in post-term nulliparous women with Bishop score </= 1 and 40% (4/10) in preterm women with Bishop score </= 1. Foley catheter achieved vaginal delivery in 83% of these women without causing an increase in the adverse neonatal outcomes. CONCLUSION: When misoprostol induction fails, Foley catheter is a safe and effective method for cervical ripening. Foley catheter can be the first treatment of choice in post-term nulliparous women or preterm women with Bishop score </= 1.

Administration, Intravaginal↗
PubMedDate not supplied

Laparoscopic management of ovarian dermoid cysts: a review of 47 cases.

BACKGROUND: Mature cystic teratomas, often referred to as dermoid cysts, are the most common germ cell tumors of the ovary. In the recent years, transvaginal sonographic diagnosis of ovarian dermoid cysts together with laparoscopic approach have greatly improved the treatment of this benign lesion. We retrospectively reviewed the outcome of laparoscopic surgery for suspected ovarian dermoid cysts. PATIENTS AND METHODS: The preoperative findings, operative techniques and postoperative complications were retrospectively reviewed in women who underwent laparoscopic surgery for dermoid cysts, between January 2000 and May 2003. RESULTS: In 47 women aged 21 to 53 years (median, 38.8 years), 93.6% had a unilateral cyst with a diameter of 17 to 108 mm (median, 51 mm). Clinical presentations were pain (62%), abnormal vaginal bleeding (21%) and ovarian torsion (2%), whilst 17% were diagnosed incidentally during routine examination. Surgery included cystectomy (57%), total (36%) or partial oophorectomy (6.4%) and laparoscopy-assisted vaginal hysterectomy with bilateral salpingo-oophorectomy (2%). During the cyst extraction, minimal spillage occurred in 42.5% of the cases and none developed chemical peritonitis. In 2 patients, conversion to laparotomy (4.3%) was required, one for sigmoid colon injury and one for malignant ovarian tumor detected via frozen section. The median operating time was 80 minutes (range, 35-180 minutes). CONCLUSION: Using strict adherence to guidelines for preoperative clinical assessment and intra-operative management, laparoscopic treatment of dermoid cysts appears to be a safe procedure.

Adult↗
PubMedDate not supplied

Temperature increase during resin cement polymerization under a ceramic restoration: effect of type of curing unit.

PURPOSE: This study measured the temperature increase induced by various types of curing units during resin cement polymerization under ceramic restorations. MATERIALS AND METHODS: The resin cement was polymerized between a ceramic specimen (diameter 5 mm, height 2 mm) and a dentin disk (diameter 5 mm, height 1 mm) with a conventional halogen light, a high-intensity halogen light, a plasma-arc light, and a light-emitting diode unit. The temperature increase was measured under the dentin disk with a J-type thermocouple wire connected to a data logger. Ten measurements were carried out for each curing unit. Difference between starting and highest temperature readings was measured, and the 10 calculated temperature changes were averaged. RESULTS: Temperature increase varied significantly depending on curing unit used. The plasma-arc light induced significantly higher temperature increases than any other curing unit. The light-emitting diode unit produced the lowest temperature changes. There were no statistically significant differences between the conventional and high-intensity halogen curing units. CONCLUSION: Polymerization with curing units characterized by high energy output (plasma-arc light) caused higher temperature changes compared to other curing units, but the temperature increase detected was not viewed as critical for pulpal health.

Analysis of Variance↗
PubMedDate not supplied

Degree of conversion and surface hardness of resin cement cured with different curing units.

OBJECTIVE: The aim of this study was to evaluate the degree of conversion and Vickers surface hardness of resin cement under a simulated ceramic restoration with 3 different curing units: a conventional halogen unit, a high-intensity halogen unit, and a light-emitting diode system. METHODS AND MATERIALS: A conventional halogen curing unit (Hilux 550) (40 s), a high-intensity halogen curing unit used in conventional and ramp mode (Optilux 501) (10 s and 20 s, respectively), and a light-emitting diode system (Elipar FreeLight) (20 s, 40 s) were used in this study. The dual-curing resin cement (Variolink II) was cured under a simulated ceramic restoration (diameter 5 mm, height 2 mm), and the degree of conversion and Vickers surface hardness were measured. For degree of conversion measurement, 10 specimens were prepared for each group. The absorbance peaks were recorded using the diffuse-reflection mode of Fourier transformation infrared spectroscopy. For Vickers surface hardness measurement, 10 specimens were prepared for each group. A load of 200 N was applied for 15 seconds, and 3 evaluations of each of the samples were performed. RESULTS: Degree of conversion achieved with Optilux 501 (20 s) was significantly higher than those of Hilux, Optilux 501 (10 s), Elipar FreeLight (20 s), and Elipar FreeLight (40 s). For Vickers surface hardness measurement, Optilux 501 (20 s) produced the highest surface hardness value. No significant differences were found among the Hilux, Optilux 501 (10 s), Elipar FreeLight (20 s), and Elipar FreeLight (40 s). CONCLUSION: The high-intensity halogen curing unit used in ramp mode (20 s) produced harder resin cement surfaces than did the conventional halogen curing unit, high-intensity halogen curing unit used in conventional mode (10 s) and light-emitting diode system (20 s, 40 s), when cured through a simulated ceramic restoration.

Dental Porcelain↗
PubMedDate not supplied

Two-year color changes of light-cured composites: influence of different light-curing units.

This study determined color changes in a composite cured with various types of curing units after two years. A hybrid (Clearfil AP-X) composite was cured with a conventional halogen, a high intensity halogen, a plasma arc and a light emitting diode unit. The specimens were stored in light-proof boxes after the curing procedure to avoid further exposure to light and stored in 37 degrees C in 100% humidity. Colorimetric values of the specimens immediately after curing and after two years were measured using a colorimeter. The CIE 1976 L*a*b color system was used to determine color differences. Differences from baseline were calculated as deltaE*ab. Data were analyzed with two-way analysis of variance (p<0.05). The deltaE*ab values varied significantly, depending on the curing unit used. The specimens cured with a plasma arc curing unit induced significantly higher color changes than any other specimen and the color differences were also visually appreciable by the non-skilled operator (deltaE*ab >2.5). The specimens cured with a high intensity halogen curing unit produced the lowest color change; however, there were no statistically significant differences among the color changes of specimens cured with conventional halogen, high intensity halogen and the light emitting diode unit, and the color changes were not clinically relevant (deltaE*ab <2.5). The results of this study suggest that composite materials undergo measurable changes due to curing unit exposure. The specimens cured with a plasma arc light showed the highest color changes as compared to specimens cured with other curing units.

Analysis of Variance↗
PubMedDate not supplied

In vivo heat transfer capacities of autopolymerizing, heat-polymerizing, and injection-molded acrylic resins.

The aim of this pilot study was to measure the heat transfer capacities of heat-polymerizing, injection-molded, and autopolymerizing acrylic resins in vivo. Two volunteers used acrylic resin removable plates and consumed hot (69 degrees C) and cold drinks (6 degrees C). Differences between oral temperature and highest and lowest temperature readings were recorded. Temperature changes for the autopolymerizing acrylic resin were found to be significantly higher than the heat-polymerizing and injection-molded acrylic resins for both cold and hot drinks. Despite the disadvantages of autopolymerizing acrylic resins, their high heat transfer capacity may be an advantage.

Acrylic Resins↗