Evaluation of the resin cement thicknesses and push-out bond strengths of circular and oval fiber posts in oval-shapes canals

PURPOSE

The aim of this study was to evaluate whether the push-out bond strength varies between oval and circular fiber posts, and to examine the effect on the resin cement thicknesses around the posts.

MATERIALS AND METHODS

Eighteen mandibular premolar roots were separated into two groups for oval and circular fiber posts systems. Post spaces were prepared and fiber posts were luted to the post spaces. Roots were cut horizontally to produce 1-mm-thick specimens. Resin cement thicknesses were determined with a metallographic optical microscope and push-out tests were done.

RESULTS

No significant differences were observed in terms of push-out bond strength between the oval and circular fiber posts (P>.05) The resin cement thicknesses of the oval posts were greater than those of the circular posts group in the coronal, middle and apical specimens (P<.05).

CONCLUSION

In the light of these results, it can be stated that resin cement thickness does not affect the push-out bond strength.     

Effect of layer thickness on the marginal and internal adaptation of laser-sintered metal frameworks

Statement of problemLaser sintering is commonly used for fabricating metal-ceramic restorations. The layer thickness of the sintering process may affect restoration adaptation. However, limited information is available regarding its impact.PurposeThe purpose of this in vitro study was to compare the marginal and internal adaptation of laser-sintered cobalt-chromium single crown frameworks sintered with layer thicknesses of 25 and 50 μm.Material and methodsThirty resin dies that represented prepared single molar abutment teeth were prepared by using a 3-dimensional printer and were divided into 3 groups (n=10) according to the method used for fabricating metal frameworks: group C, metal frameworks fabricated by using the lost-wax method (control); group L25, metal frameworks fabricated by using direct metal laser melting with a layer thickness of 25 μm; and group L50, metal frameworks fabricated by using direct metal laser melting with a layer thickness of 50 μm. After fabricating the metal frameworks, 15 vertical marginal discrepancy measurements were made in each axial region (mesial, distal, buccal, and lingual) using a stereomicroscope. Next, all the specimens were sectioned from the midline, and 5 internal discrepancy measurements were made in each internal region (inner marginal, axial, and occlusal). The data were analyzed statistically by using 1-way ANOVA, the Tukey honestly significant difference, and Tamhane T2 tests (α=.05).ResultsThe highest marginal and internal discrepancy values were obtained for metal frameworks in group C, and these values were significantly different (P<.001) from those obtained for metal frameworks in the other 2 groups. No significant difference was observed in the marginal and internal discrepancy values of metal frameworks in groups L25 and L50.ConclusionsThese results indicate that layer thickness does not affect the adaptation of laser-sintered metal frameworks, yet both sintering parameters yielded significantly lower mean marginal discrepancy values than the cast group.     

Regulatory neuropeptides (ghrelin,obestatin and nesfatin-1) levels in serum and reproductive tissues of female and male rats with fructose-induced metabolic syndrome

Although, the exact mechanisms underlying the development of the metabolic syndrome (MetS) are not still completely understood, obesity, circulated peptide hormone levels and their interaction with genetic factors are considered largely responsible. The purpose of this study is to explore how the levels of ghrelin, obestatin (OBS) and NUCB2/nesfatin-1 (NES)/NUCB2 change in serum and the reproductive tissues of female and male rats with fructose-induced metabolic syndrome, and whether the levels of each hormone is correlated with the hormones involved with fertility. Experiments were conducted on 5-week-old Sprague–Dawley male and female rats assigned to either a control group or a MetS group. Controls were fed standard rat food and water ad libitum, while the MetS group was fed standard food with 10% (v/v) fructose solution added to their drinking water for 12 weeks with a 12/12 h photoperiod circle. Then, all animals were sacrificed after a one night fast. Peptides levels in the serum and reproductive tissues of rats were studied using the ELISA method while the immunoreactivity of reproductive system peptide hormones were shown by immunohistochemical staining method. Furthermore, the other biochemical parameters were measured using Konelab-60 equipment and infertility hormones were measured with Immulite2000. Fasting serum insulin, glucose, triglyceride, alanine aminotransferase (ALT), gamma glutamyl transpeptidase (GGT), low-density lipoprotein cholesterol (LDL-C), and total cholesterol (TC) levels were statistically significantly higher, and the amount of high density lipoprotein cholesterol (HDL-C) was significantly lower, in the MetS groups. Serum and tissue supernatant NES levels were significantly higher in the rats with MetS than the control group. Ghrelin, OBS and NES were expressed in the cytoplasm, concentrated around the apical parts of the epithelial cells in the reproductive tissues of the rats. The amounts of ghrelin were lower in the reproductive tissues of the animals with MetS, while NES levels in the same tissues increased. Obestatin also decreased, though not in the seminal glands.     

Pseudohypoparathyroidism presenting with ventricular arrhythmia: a case report

Pseudohypoparathyroidism (PHP) is a rare disorder characterized by varying degrees of unresponsiveness to parathyroid hormone. Patients usually present with hypocalcemia-induced seizures or tetany, whereas no case of hypocalcemia-induced cardiac arrhythmia in PHP has been described to date. In this paper, we report the case of a male adolescent with PHP type 1a who presented with hypocalcemia-induced ventricular extrasystoles (bigeminy, trigeminy) and mild corrected QT interval prolongation. The patient had brachydactyly and his second fingers and toes were longer than the others, a finding consistent with PHP. Laboratory tests detected hypomagnesemia, as well as elevated levels of creatine kinase and lactate dehydrogenase. Ventricular arrhythmia and abnormal laboratory tests improved with calcium supplementation and vitamin D treatment. The findings in this patient suggest that hypomagnesemia may make patients with PHP more susceptible to hypocalcemia and may thus prompt a state of hypocalcemia-induced arrhythmia or other cardiac complications.     

Safety of ESWL in elderly: Evaluation of independent predictors and comorbidity on stone‐free rate and complications

Aim: Urinary stone disease affects people of all ages. With its satisfactory efficacy ranges in all age groups and lack of side‐effects, extracorporeal shock wave lithotripsy (ESWL) has become the preferred treatment modality for uncomplicated renal and proximal calculi ≤20 mm. In the present study, we aimed to assess the safety and efficacy of the ESWL treatment in elderly patients. Methods: A retrospective study was carried out on patients aged over 65 years who underwent shock wave lithotripsy at our Department from 2009 to 2011, with a Siemens Lithostar electromagnetic shockwave lithotripter. A total of 231 patients (157 males, 74 females) out of 1694 (13.6%) were studied. The patients were divided into two groups (group 1 = 65–70; group 2 >70). The effect of age and other possible predicting factors (sex, stone localization and stone size) were investigated. Concomitant diseases and related complications were also evaluated. Results: An overall stone‐free rate (SFR) of 82.2% was found. The influence of sex on SFR was non‐significant. There was no significant difference when comparing SFR between the age groups. When patients were divided into those with renal and ureteral stones, the SFR were 94.4% and 67.6% (P < 0.01), respectively. The SFR of the stone size groups, ≤10 mm and >10 mm were 80% and 84.4%, respectively. Comorbidity was present in 148 patients. Complications were noted in 56 of 231 patients. Of 56 patients, 43 had minor complications and 13 major complications. Conclusion: ESWL seems to be an effective first‐line treatment choice for urinary stones in elderly patients with careful patient selection and personalized preparation. Geriatr Gerontol Int 2012; 12: 413–417.