Thermal cycling distortion of porcelain fused to metal fixed partial dentures

Statement of problem. The initial fit of porcelain fused to metal restorations deteriorates during the firing cycle of porcelain. Purpose. This study evaluated thermal cycling distortion of 3-unit porcelain fused to metal frameworks at different firing stages. Material and methods. A master model was designed to represent the 2 abutments of a 3-unit fixed partial denture replacing a missing mandibular molar. Standard techniques were used to fabricate 10 castings. Half of the copings were cast in a Ni-Cr alloy and the other half in a Pd-Cu alloy. Framework distortion was measured by means of inner fit changes, horizontal linear measurements of the framework length, and vertical fit changes of each retainer. Measurements were made (1) initially, (2) after degassing firing, and (3) after glaze firing. Differences between the firing cycles created distortion values of the retainers in 3 dimensions. Repeated measures ANOVA was used to analyze data statistically. Results. Measured differences between the 2 firing stages ranged from –47 to 81.7 μm. For both alloy groups, retainers showed increase in vertical gap that implied poorer vertical fit after porcelain application. Mean values of inner fit change recorded for porcelain application firing were higher in magnitude than the values of metal-conditioning firing. In addition, no statistically significant differences were found among alloy types. Conclusions. A 3-dimensional distortion was observed both in Pd-Cu and Ni-Cr frameworks during porcelain firing cycle. The distortion seen after porcelain application firing was significantly greater than that seen after metal-conditioning firing. This result can be attributed to these factors, contamination of porcelain to the inner surface of metal coping and reduction in resilience of metal. (J Prosthet Dent 1998;80:654-60.)     

Evaluation of various root canal filling materials in primary molar pulpectomies: an in vivo study

PURPOSE: To evaluate the clinical and radiographic success of zinc oxide-eugenol (ZOE), Calcicur, Sealapex and Vitapex in primary molar pulpectomies. METHODS: 80 primary molars, showing signs of pulpal and/or periapical involvement, with no abnormal mobility, were selected from 76 children aged between 4-9 years-old, free from systemic disease. Radiographic evaluation was done to exclude teeth showing internal or pathological external root resorption and/or inadequate bone support. The selected teeth (20 in each group) were randomly treated with ZOE, Sealapex, Calcicur and Vitapex. The procedure involved primarily a one-visit pulpectomy. The teeth were evaluated clinically and radiographically every 2 months for a period of 18 months. RESULTS: In the ZOE group, all pulpectomies were successful. In the Sealapex group, two pulpectomies and in the Calcicur group, four pulpectomies showed complete resorption of the material in the root canal. Although re-treatment was performed, those teeth had to be removed due to pathological root resorption. In the Vitapex group, although six pulpectomies showed resorption of the filling material within the canals, this had no effect on the clinical and radiographical success of the treatment.     

The Healing Effects of Autologous Mucosal Grafts in Experimentally Injured Rabbit Maxillary Sinuses

ObjectivesHealing processes of the nose and paranasal sinuses are quite complex, and poorly understood. In this study, we aimed to compare the effect of mucosal autologous grafts on the degenerated rabbit maxillary sinus mucosa with spontaneous wound healing. It is hypothesized that mucosal grafts will enhance ciliogenesis and improve the morphology of regenerated cilia.MethodsTen female New Zealand rabbits were included in the study. They underwent external maxillary sinus surgery through a transcutaneous approach. A total of 20 maxillary sinuses were randomly divided into 2 groups: ‘spontaneous healing group’ and ‘autologous graft group.’ The animals were sacrificed at the 14th day after the surgery. Scanning electron microscope (SEM), and light microscope were used for the evaluation.ResultsCellular composition of the graft group is better than the spontaneous healing group. The graft group had larger areas covered with ciliary epithelium than the spontaneous healing group, and the mean length of the cilias were also longer. Additionally, there were wider cilia with abnormal morphology areas in the spontaneous healing group.ConclusionIn our opinion, covering of the denuded areas with a graft improves re-epithelization, and may prevent the early complications after sinus surgeries.     

In vitro evaluation of the dissolving effect of solvents on root canal sealers

The purpose of this in vitro study was to evaluate two commonly used gutta-percha solvents for their effectiveness in dissolving several types of root canal sealers. Seven different sealers (AH26, AH Plus, Diaket, Roekoseal, Sankin Apatite Root Sealer, Sealapex, and Sultan U/P) were used in this study. After mixing according to the manufacturers' directions, each material was syringed into 30 glass capillary tubes, and a total of 210 tubes were placed in a humidifier at 37 degrees C for one week to allow the materials to set completely. Each group of 30 tubes, obturated with one type of sealer, was then randomly divided into three subgroups, including 10 tubes each. Chloroform was used in the first ten tubes from each sealer group. Halothane was used for the second group. In the last group, the sealer was removed with files, without using any solvent. The time necessary to pass a file through to the end of the tube was recorded for each sample in seconds. Results were analyzed using one-way analysis of variance. Sealapex did not set at all unless in contact with air. Roekoseal did not adhere to the glass capillary tubes, and was therefore easily removed from the tube in all samples. AH26 and AH Plus root canal sealers tightly adhered to the tube walls, so none of the techniques were effective in removing them from the tubes within 30 min. Diaket root canal sealer was easily removed using solvents (P < 0.05). There was no advantage in using solvents to remove Sankin Apatite Root Sealer (P > 0.05). Solvents were found to be very effective in dissolving the Sultan U/P root canal sealer (P < 0.05).     

Comparison of secondary implantation of flexible open-loop anterior chamber and scleral-fixated posterior chamber intraocular lenses

PURPOSE: To analyze and compare the outcomes and complication rates of secondary implantation of flexible, open-loop, anterior chamber intraocular lenses (AC IOLs) and single-piece, scleral-fixated, posterior chamber IOLs (PC IOLs). SETTING: Departments of Ophthalmology, Gaziantep University Medical Faculty, Research Hospital, Gaziantep, and In?nü University Medical Faculty, Research Hospital, Malatya, Turkey. METHODS: This study comprised 124 eyes of 113 aphakic patients (61 men, 52 women) with insufficient capsule support who had secondary IOL implantation from January 1997 to June 2001. In Group 1 (n = 73 eyes), a flexible, open-loop AC IOL was implanted and in Group 2 (n = 51 eyes), a single-piece, scleral-fixated PC IOL. The mean follow-up was 34 months (range 6 to 53 months) and took place at several different clinical settings. The mean interval between the initial cataract operation and secondary IOL implantation was 63 months (range 6 months to 12 years). The postoperative outcomes, safety, efficacy, and complication rates were analyzed, and the preoperative and postoperative best spectacle-corrected visual acuities (BSCVAs) were compared. RESULTS: The postoperative mean BSCVA was 20/34.8 +/- 45.2 (SD) in Group 1 and 20/32.1 +/- 33.7 in Group 2; the difference was not significant (P =.718). A BSCVA of 20/40 or better was achieved in 62 eyes (84.9%) in Group 1 and 45 eyes (88.2%) in Group 2. A BSCVA of 20/25 or better was achieved in 40 eyes (54.8%) and 33 eyes (64.7%), respectively. The difference between the 2 groups was not significant (P =.472). Complications occurred in 25 eyes (34.2%) in Group 1 and 13 eyes (25.5%) in Group 2 (P >.05). The most frequent complications in Group 1 were early transient corneal edema, intraocular pressure elevation, cystoid macular edema, hyphema, secondary glaucoma, and iris capture or pupil decentration and in Group 2, suture erosion, a tilted or decentered IOL, fibrin reaction, and vitreous prolapse into the anterior chamber. CONCLUSIONS: The AC IOLs and PC IOLs were safe and effective for secondary implantation to correct aphakia. Secondary implantation of the scleral-fixated PC IOL seemed to provide a more favorable outcome and a lower complication rate than the open-loop AC IOL in complicated cataract cases with inadequate capsule and zonular support. As scleral-fixated PC IOL implantation is technically more difficult than AC IOL implantation, the decisive factor in choosing a secondary IOL is surgical experience. Long-term comparison of both techniques is required.     

One-year prevalence and the impact of migraine and tension-type headache in Turkey: a nationwide home-based study in adults

Several studies have shown that the prevalence of migraine and tension-type headache (TTH) varied between different geographical regions. Therefore, there is a need of a nationwide prevalence study for headache in our country, located between Asia and Europe. This nationwide study was designed to estimate the 1-year prevalence of migraine and TTH and analyse the clinical features, the impact as well as the demographic and socio-economic characteristics of the participant households in Turkey. We planned to investigate 6,000 representative households in 21 cities of Turkey; and a total of 5,323 households (response rate of 89%) aged between 18 and 65 years were examined for headache by 33 trained physicians at home on the basis of the diagnostic criteria of the second edition of the International Classification of Headache Disorders (ICHD-II). The electronically registered questionnaire was based on the headache features, the associated symptoms, demographic and socio-economic situation and history. Of 5,323 participants (48.8% women; mean age 35.9 ± 12 years) 44.6% reported recurrent headaches during the last 1 year and 871 were diagnosed with migraine at a prevalence rate of 16.4% (8.5% in men and 24.6% in women), whereas only 270 were diagnosed with TTH at a prevalence rate of 5.1% (5.7% in men and 4.5% in women). The 1-year prevalence of probable migraine was 12.4% and probable TTH was 9.5% additionally. The rate of migraine with aura among migraineurs was 21.5%. The prevalence of migraine was highest among 35–40-year-old women while there were no differences in age groups among men and in TTH overall. More than 2/3 of migraineurs had ever consulted a physician whereas only 1/3 of patients with TTH had ever consulted a physician. For women, the migraine prevalence was higher among the ones with a lower income, while among men, it did not show any change by income. Migraine prevalence was lower in those with a lower educational status compared to those with a high educational status. Chronic daily headache was present in 3.3% and the prevalence of medication overuse headache was 2.1% in our population. There was an important impact of migraine with a monthly frequency of 5.9 ± 6, and an attack duration of 35.1 ± 72 h, but only 4.9% were on prophylactic treatment. The one-year prevalence of migraine estimated as 16.4% was similar or even higher than world-wide reported migraine prevalence figures and identical to a previous nation-wide study conducted in 1998, whereas the TTH prevalence was much lower using the same methodology with the ICHD-II criteria.     

Effects of intraperitoneal melatonin on caustic sclerosing cholangitis due to scolicidal solution in a rat model

Background: Hydatid disease is a worldwide health problem. Treatment is surgical or percutaneous, using scolicidal agents. Caustic sclerosing cholangitis might develop after the contact of scolicidal agents with the biliary ducts. Melatonin, an antioxidant, anti-inflammatory, and anticarcinogenic agent, might be used in the treatment of caustic sclerosing cholangitis due to its possible preventive effects on fibrosis and cell damage.Objective: The aim of the study was to investigate the effects of melatonin on an experimentally developed caustic sclerosing cholangitis with scolicidal solution (formalin) in a rat model.Methods: Forty female Sprague-Dawley rats aged 11 to 13 weeks and weighing 250 ± 30 g were randomly assigned to 1 of 4 groups of 10: formalin 5% at 0.5 mL/d + melatonin placebo; formalin placebo + intraperitoneal melatonin 10 mg/kg/d; formalin 5% at 0.5 mL/d + melatonin 10 mg/kg/d; and formalin placebo and melatonin placebo (control). Hepatobiliary function was assessed using dynamic scintigraphy with technetium-99m-mebrofenin on study day 60. The histology of the liver and biliary duct specimens was examined on study day 60. In each group, histopathologic alterations were scored as absent, slight, mild, or severe.Results: Mean severity scores for parenchymal necrosis in the liver (P < 0.01), portal fibrosis (P < 0.01), biliary duct proliferation (P < 0.001), cholangitis/ pericholangitis (P < 0.01), hyperemia in the biliary ducts (P < 0.01), and fibrosis (P < 0.01) were significantly lower in rats treated with formalin + melatonin compared with those treated with formalin alone. No significant differences were observed between the 3 treatment groups with respect to t_½, a parameter used to assess the secretion function of the hepatocytes. However, the t_½ was significantly longer in the treatment groups compared with controls (P < 0.001).Conclusion: In this experimental study in a rat model of caustic sclerosing cholangitis, the histopathologic and scintigraphic findings suggested that melatonin is effective in attenuating the damage caused by scolicidal agents on the liver and biliary ducts.     

Newborn PKU screening in Turkey: at present and organization for future.

At present, pkenylketonuria screening is a national child health program in Turkey which is carried out collaboratively by the Ministry of Health and three University Children's Hospitals in Ankara, Istanbul and Izmir. Since 1986 the number of cities included in the screening program has gradually increased, now and it covers all the metropolises the country. A total of 383 babies were found with persistent hyperphenylalaninemia (1:4,172) among 1,605,582 babies screened by the Guthrie test at the Hacettepe Screening Center in Ankara. By taking into account pretreatment phenylalanine levels and phenlyalanine tolerances at five years of age, the numbers of classical and mild-moderate phenylketonuria and mild hyperphenylalaninemia cases were 216, 102 and 58, respectively. The major problems encountered in the screening program and in management of the detected cases were unsatisfactory sample collection, early discharge from maternity hospitals, difficulties in reaching some detected cases, and noncompliance with dietary therapy due to illiterate parents or to lack of social insurance. To screen and treat all newborns for phenylketonuria and to include at least hypothyroidism in the screening program, there is a need for a more disciplinary intersectoral approach than exists at present.     

Synthesis of some 1-(2-naphthyl)-2-(imidazole-1-yl)ethanone oxime and oxime ether derivatives and their anticonvulsant and antimicrobial activities.

In this study, oxime and oxime ether derivatives of anticonvulsant nafimidone [1-(2-naphthyl)-2-(imidozole-1-yl)ethanone] were prepared as potential anticonvulsant compounds. Nafimidone oxime was synthesized by the reaction of nafimidone and hydroxylamine hydrochloride. O-Alkylation of the oxime by various alkyl halides gave the oxime ether derivatives. Anticonvulsant activity of the compounds was determined by maximal electroshock (MES) and subcutaneous metrazole (scMet) tests in mice and rats according to procedures of the Antiepileptic Drug Development (ADD) program of the National Institutes of Health (NIH). In addition to anticonvulsant evaluation, compounds were also screened for possible antibacterial and antifungal activities because of the structural resemblance to the azole antifungals, especially to oxiconazole. All compounds were evaluated against three human pathogenic fungi and four bacteria using the microdilution method. Most of the compounds exhibited both anticonvulsant and antimicrobial activities; the O-alkyl substituted compounds (2, 3, 4 and 5) were found to be more active than the O-arylalkyl substituted compounds in both screening paradigms.