Effect of sandblasting on fracture load of titanium ceramic crowns

Purpose of the Study:

It is difficult to achieve a reliable bond between the titanium and veneering porcelain. The aim of this study was to evaluate the bond strength between titanium ceramic crowns.

Materials and Methods:

The surfaces of titanium copings were divided in two groups. Group A sandblasted with 250 um (n = 10) and Group B without sandblasting (n = 10). Low-fusing porcelain was bonded over copings. A universal testing machine was used to determine the fracture load (N) of the crowns. All data were compared using Student''s t-test.

Results:

There was a significant difference in fracture toughness between two groups (P = 0.05). The mean value of fracture strength for Group A was 721.66 N and for Group B was 396.39 N.

Conclusions:

Sandblasting improves the bond strength between titanium, and ceramic, mechanical bonding plays a crucial role in the bonding between titanium and ceramic.Key Words: Bonding, fracture load, sandblasting, titanium     

One year follow-up of alcohol and illicit substance use in first-episode psychosis: Does gender matter?

Longitudinal studies on first-episode psychosis (FEP) patients have shown a decrease of substance use disorders (SUDs) over the first years of illness, but there has been less focus on the gender aspect. The present study examines stability of alcohol and illicit substance use, with specific focus on gender, in a one year follow-up investigation of 154 FEP patients (91 men, 63 women) in Oslo, Norway, using criteria for DSM-IV substance use disorder diagnosis, the Alcohol Use Disorders Identification Test (AUDIT) and the Drug Use Disorders Identification Test (DUDIT). The results show that cannabis was the most frequently used illicit substance at both times. Significantly more men (34%) than women (13%) had a current illicit SUD at baseline. At follow-up, the rate of illicit SUDs was significantly reduced in men (18%) but not in women (11%). There were no significant gender differences in the rate of current alcohol use disorders (AUD) (men 14%; women 8%) at baseline, and no significant reduction in AUD in any of the genders at follow-up. At follow-up, total AUDIT and DUDIT scores were reduced in men only. In conclusion, the high and persistent rate of SUDs, particularly of cannabis, among men and women during the first year of treatment for psychosis should be addressed in the clinical management of the patients. Female FEP patients who are also substance users may be particularly vulnerable in this regard and warrant closer attention.     

An In Vitro Evaluation of the Microleakage under Complete Metal Crowns Using Three Adhesive Luting Cements

Despite the material advancements and precise laboratory techniques, cement lines are inevitable in fixed prosthodontics which leads to increased dependence on the integrity of the cement to maintain the marginal seal. The material class of luting agent is known to influence microleakage. Studies of cement dissolution and disintegration have produced varying results. Hence, this study was done to evaluate marginal leakage under complete metal crowns using three adhesive cements, two resin cements (one self cure, one dual cure) and a glass ionomer cement. Metal crowns were prepared on sixty intact extracted premolars and were randomly divided into three groups of twenty each, with each group using a different cement for luting. All the samples were then subjected to thermocycling and were sectioned using a diamond saw. Reflected Binocular Stereomicroscope at 100× magnification was used to study the extent of microleakage at both metal cement (MC) and tooth cement (TC) interface, at two opposite margins of each sectioned specimen. Data was analyzed with a one way analysis of variance. For comparison among the groups multiple comparison Bonferroni test was done. Within group data was analysed with independent student t test. Between three groups, metal crowns cemented with multilink cement showed significantly less microleakage at both the interfaces. Glass ionomer cement recorded maximum combined microleakage amongst three cements irrespective of the interfaces. Within group, glass ionomer and multilink cement showed more microleakage at MC interfaces than at TC interface. A complex interaction between variables related to dental restoration, luting agent and tooth structure probably influence microleakage. In vitro studies must always be followed by in vivo studies before definite conclusion can be drawn.     

Complications following hip arthroscopy: a retrospective review of the McMaster experience (2009–2012)

Background

The use of hip arthroscopy has been steadily rising as technology, experience and surgical education continue to advance. Previous reports of the complication rate associated with hip arthroscopy have varied. The purpose of this study was to report our experience with hip arthroscopy complications at a single Canadian institution (McMaster University).

Methods

We performed a retrospective chart review of 2 hip arthroscopists at the same institution to identify patients who had undergone the index surgery and had been followed for a minimum of 6 months postoperatively. We used a standard data entry form to collect information on patient demographic and clinical characteristics, including age, sex, surgical indication and type of complication if any.

Results

A total of 211 patients underwent 236 hip arthroscopies. The mean age at time of surgery was 37 ± 13 years and mean follow-up was 394 ± 216.5 days. The overall complication rate associated with hip arthroscopy was 4.2% (95% confidence interval 2.3%–7.6%). We identified 4 major and 6 minor complications.

Conclusion

Overall, hip arthroscopy appears to be safe, with minor complications occurring more frequently than major ones. However, surgeons should recognize the possibility of serious complications associated with this procedure. Future research should focus on prospective designs looking for potential prognostic factors associated with hip arthroscopy complications.     

Tear film measurements in four different ethnic groups: Malay, Chinese, Indian and Nigerian

AIM: To compare the non-invasive tear film break-up time (NIBUT), tear break up time (TBUT), basal tear secretion (BTS) and blink rate in four ethnic groups: Malay, Chinese, Indian and Nigerian. METHODS: Totally 120 healthy (61 males and 59 females) subjects (without dry eye symptoms and ocular surface disorder) with the age 20 to 39 years were recruited; 30 were Malays, 30 were Chinese, 31 were Indians and 29 were Nigerians. Based on McMonnies questionnaire and clinical examination, normal subjects were selected. NIBUT, TBUT, BTS were assessed in only one eye (right) of each subject and blink rate was also assessed. RESULTS: There was significant difference in the NIBUT, TBUT, BTS and blink rate among 4 different ethnic groups (P=0.018, 0.001, 0.011, and 0.004 respectively). No statistically significant difference of NIBUT, TBUT, BTS and blink rate was found between the genders among different ethnic groups. Indian had higher median for NIBUT (10±6s), TBUT (7±5s) and BTS (20±20 mm) than other races. Chinese had lower median for NIBUT (7.5±4s) and TBUT (4±2s) while Malay had for BTS (9.5±16 mm) among the groups. There was no significant correlation of blink rate with NIBUT (r=-0.119, P=0.195), TBUT (r=-0.086, P=0.352), and BTS (r=-0.123, P=0.180) respectively. CONCLUSION: The tear-film measurement values are variability in four ethnic groups.     

Ring-opening cyclization of activated spiro-aziridine oxindoles with heteroarenes: a facile synthetic approach to spiro-oxindole-fused pyrroloindolines

Herein, we report a facile tandem approach for the synthesis of both spiro-oxindole-fused pyrroloindolines and benzofurano-pyrrolidines via a Lewis acid-catalyzed domino ring-opening with concomitant ring annulation using activated spiro-aziridines and heteroarenes. This method offers a new class of novel spiro-fused polycyclic pyrrolidines in a one-pot and sustainable manner with good yields and high diastereoselectivity. In addition, the structure of 3d was confirmed by single X-ray crystallography analysis.

Herein, we report a facile tandem approach for the synthesis of both spiro-oxindole-fused pyrroloindolines and benzofurano-pyrrolidines via a Lewis acid-catalyzed domino ring-opening annulation using activated spiro-aziridines and heteroarenes.     

Tip to apex distance in femoral intertrochanteric fractures: a systematic review

Background

Hip fractures are associated with high morbidity, mortality, and cost. Implants used for hip fracture fixation can fail for many reasons including lag screw cut-out. Tip–apex distance (TAD) is indicative of the position and depth of a screw in the femoral head and has been shown to be associated with cut-out failure. We conducted a systematic review of the published literature to quantify the association between TAD and cut-out failure for patients undergoing hip fracture fixation surgery.

Methods

We performed a search of the Medline, Embase, and Cochrane databases. We performed abstract and full text reviews independently and in duplicate. We used a random effects model to combine, in duplicate, the incidence of cut-out for patients who had TAD <25 mm and TAD >25 mm. We also combined mean TAD values for patients who had cut-out failure and those who did not.

Results

Seventeen studies were eligible for this review, four of which were included in combined analysis of dichotomous outcomes and seven in combined analysis of continuous outcomes. Patients with TAD >25 mm had a significantly greater risk of cut-out than patients with TAD <25 mm (RR = 12.71). Patients who experienced implant cut-out had significantly higher TAD scores than those who did not (mean difference = 6.54 mm).

Conclusion

Tip–apex distance is an important concept in relation to cut-out failure of hip fracture fixation surgery. Surgeons should understand and apply the concept of TAD to improve outcomes for their patients.