Effect of platform switching on crestal bone stress distribution around 3i implants: a finite element analysis

Over the last few years, concept of platform switching has gained popularity for reducing degree of crestal bone resorption. Many researchers believe that, this theory can be used for improving stress distribution in implant-bone interface. The purpose of this three dimensional Finite Element Analysis [FEA] was to study and compare stress distribution in implant-bone interface and implant-abutment interface of 3i implants [Biomet 3i, USA] in mandibular molar area. For this FEA, computed tomography [CT] images of an adult human mandible was used to make the three-dimensional model of posterior edentulous mandible .The implant systems which used was the 3i system consisted of 3i fixtures: 4 and 5 mm in diameter and 11.5 mm in length, and 3i Certain abutment 4.1 and 5mm [Biomet 3i, USA]. This implant systems were assembled on the mandible model in 3 different designs: a platform-switched configuration; MODEL 4: 4-mm 3i fixture, 4.1-mm abutment; MODEL 5: 5-mm 3i fixture, 5-mm abutment; MODEL 6: 5-mm 3i fixture, 4.1-mm abutment, a platform-switched configuration. A linear static analysis was performed on the prepared 3D solid models with two different oblique load of 100 and 250 N in the lingobuccal direction with 15 degrees of inclination on the center of the abutment. Regardless of the implant system used, maximum Von Mises stresses in cortical bone around implants were lower in platform switched models compared to matching diameter implant-abutment. This effect was not related to the usage of larger implant diameters in these models. However, Von Mises stresses in implant-abutment interface were the lowest in models with larger implant diameter. The platform switching technique reduces the stress concentration in the area of crestal bone-implant interface and shifted it to the area of implant-abutment interface. In the present study, this stress reduction was not

[Prevalence and persistence of health problems after child birth and maternal correlations with parity]

After delivery, family's attention changes from mother to child, while mothers tend to get very busy and do not pay attention to their health. The aim of this study was to determine prevalence and persistence of health problems after child birth and maternal correlations with parity In this descriptive-longitudinal, study 308 mothers who visited Mahabad community health centers for parental care [36-38 weeks] were selected. Instrument in this study was Postpartum Morbidity Scale, which developed by researcher. Content validity, internal consistency [0.94] and test-retest reliability [0.98] was measured. Data gathered by interview at 7 days, 8 weeks and 12 months after delivery and analyzed by SPSS/18. To determine difference and causing problems among multiparous women primiparous, Chi[2] was used and 95% confidence interval was used to determine the relative risk. The result showed that common reported problems at first and second stage were backache 64% and 60% and fatigue 63% and 60% respectively. However, after 12 months of the delivery fatigue was 43%. During 7 days of delivery, we found significant relationship between backache [P=0.005], headache [P=0.013], tiredness [P=0.008], side effect of anesthesia [P=0.041] and sleep problems [P=0.001] with multiparous mothers. These values after 8 weeks of delivery were backache [P=0.047], stitches infection [P=0.023], urinary tract infection [P=0.000], sex problems [P=0.003], postpartum blue [P=0.002], sleep problems [P=0.001] reported more between multiparous.12 months after delivery, there were a significant relation between postpartum blue [P=0.024], sex problem [P=0.001], sleep problems [P=0.036] and multiparous of mothers. Due to high prevalence of postpartum morbidities and lack of attention to solving these problems, changing the postpartum regular care and offering educational courses to mothers are necessary and highly recommended

Epidemiological evaluation of transfusion transmitted diseases in Ardabil in Tasoua and Ashoura 1381[2003]

Transfusion transmitted diseases [TTD] are of great concern because of their high mortality and morbidity rate among blood recipients; HBV, HCV and HIV are of the infectious agents playing an important role in this regard. A cross-sectional study was conducted for estimation of TTD among blood donors in Tasoua and Ashoura [2003] in Moharram month that is a religious month for Muslims, especially Shiites, and for evaluation of the motivation of 441 donors for blood donation. To this end, a questionnaire including 51 questions were prepared to be filled out by donors. HBsAg positive and HCV Ab positive prevalence rates were respectively 1.4 and 0.2%. Majority of donors have religious motivation [92%] but a minority cut their heads with dagger as a religious practice. 83% of HBsAg positive donors had a history of blood donation in the past. Because common daggers may be used among religious people, probability of TTD can be high in these groups. Majority of HBsAg positive donors had a history of blood donation in the past and for an unknown reason probability of TTD in repeat donors was higher than first time donors. The prevalence of HBsAg positive and HCVAb positive in ordinary blood donors in Ardabil Blood Transfusion Center is lower than their prevalence rate in Tasoua and Ashoura donors