Evaluation of Flexural Strength of Polymethyl Methacrylate modified with Silver Colloidal Nanoparticles subjected to Two Different Curing Cycles: An in vitro Study.

AIM: Silver colloidal nanoparticles have been incorporated into acrylic resins to induce antimicrobial properties. However, as additives, they can influence the mechanical properties of the final product. Mechanical properties are also dependent on different curing cycles. The aim of this study was to evaluate flexural strength of a denture base resin incorporated with different concentrations of silver colloidal nanoparticles subjected to two different curing cycles. MATERIALS AND METHODS: Lucitone 199 denture base resin was used into which silver colloidal nanoparticles were incorporated at 0.5 and 5% by polymer mass. Specimens devoid of nanoparticles were used as controls. A total of 60 specimens were fabricated and divided into two groups. Each group was divided into three subgroups consisting of 10 specimens each. The specimens were fabricated according to American Dental Association (ADA) specification No. 12 and tested for flexural strength using universal testing machine. RESULTS: Silver colloidal nanoparticle incorporation at 0.5% concentration increased the mean flexural strength in both curing cycles by 7.5 and 4.4%, respectively, when compared with the control group. CONCLUSION: The study suggested that the mean flexural strength value of 0.5% silver colloidal nanoparticles in denture base resin was above the value of the control group both in short and long curing cycles, which makes it clinically suitable as a denture base material. However, at 5% concentration, the statistically significant amount of decrease in flexural strength compared with the value of control group both in short and long curing cycles gives it a questionable prognosis. CLINICAL SIGNIFICANCE: The specimens incorporated with the antimicrobial agent 0.5% silver colloidal nanoparticles and processed by long curing cycles showed significant increase in its flexural strength compared with the control group, which makes it clinically suitable as a denture base material.

Fracture Resistance of Teeth Restored with Various Post Designs and Cemented with Different Cements: An In-vitro Study.

BACKGROUND: Studies have been carried out on endodontically treated teeth restored with and without ferrule, and influence of the cementing medium, to evaluate their effect on fracture resistance. This study was conducted on 28 freshly extracted maxillary central incisors. Specimens were restored with two types of post designs, and cemented with two different luting agents, and tested for fracture resistance. MATERIALS AND METHODS: A total of 28 freshly extracted maxillary central incisors were used. Specimens were restored with two types of post designs and cemented with two different luting agents and tested using Instron universal testing machine. The statistical analysis was performed using the Kruskal-Wallis test (H) and Tukey honest significant test. RESULTS: Ferrule helped in increasing the fracture resistance of endodontically treated teeth. Resin cement showed better results than zinc phosphate cement. The combination of the post with ferrule and resin cement showed the greatest resistance. The combination of the post without ferrule and zinc phosphate cement showed the least resistance. Resin cement increased the resistance of even without ferrule. CONCLUSION: There was a positive effect of a ferrule in increasing the fracture resistance. Resin cement showed better resistance than zinc phosphate cement.

Assessment of facility readiness and provider preparedness for dealing with postpartum haemorrhage and pre-eclampsia/eclampsia in public and private health facilities of northern Karnataka, India: a cross-sectional study.

BACKGROUND: The maternal mortality ratio in India has been declining over the past decade, but remains unacceptably high at 212 per 100,000 live births. Postpartum haemorrhage (PPH) and pre- eclampsia/eclampsia contribute to 40% of all maternal deaths. We assessed facility readiness and provider preparedness to deal with these two maternal complications in public and private health facilities of northern Karnataka state, south India. METHODS: We undertook a cross-sectional study of 131 primary health centres (PHCs) and 148 higher referral facilities (74 public and 74 private) in eight districts of the region. Facility infrastructure and providers' knowledge related to screening and management of complications were assessed using facility checklists and test cases, respectively. We also attempted an audit of case sheets to assess provider practice in the management of complications. Chi square tests were used for comparing proportions. RESULTS: 84.5% and 62.9% of all facilities had atleast one doctor and three nurses, respectively; only 13% of higher facilities had specialists. Magnesium sulphate, the drug of choice to control convulsions in eclampsia was available in 18% of PHCs, 48% of higher public facilities and 70% of private facilities. In response to the test case on eclampsia, 54.1% and 65.1% of providers would administer anti-hypertensives and magnesium sulphate, respectively; 24% would administer oxygen and only 18% would monitor for magnesium sulphate toxicity. For the test case on PPH, only 37.7% of the providers would assess for uterine tone, and 40% correctly defined early PPH. Specialists were better informed than the other cadres, and the differences were statistically significant. We experienced generally poor response rates for audits due to non-availability and non-maintenance of case sheets. CONCLUSIONS: Addressing gaps in facility readiness and provider competencies for emergency obstetric care, alongside improving coverage of institutional deliveries, is critical to improve maternal outcomes. It is necessary to strengthen providers' clinical and problem solving skills through capacity building initiatives beyond pre-service training, such as through onsite mentoring and supportive supervision programs. This should be backed by a health systems response to streamline staffing and supply chains in order to improve the quality of emergency obstetric care.

Prevention of Parent to Child Transmission (PPTCT) program data in India: an emerging data set for appraising the HIV epidemic.

BACKGROUND: Evidence based resource allocation and decentralized planning of an effective HIV/AIDS response requires reliable information on levels and trends of HIV at national and sub-national geographic levels. HIV sentinel surveillance data from antenatal clinics (HSS-ANC) has been an important data source to assess the HIV/AIDS epidemic in India, but has a number of limitations. We assess the value of Prevention of Parent to Child Transmission (PPTCT) programme data to appraise the HIV epidemic in India. METHODS/FINDINGS: HIV data from PPTCT sites were compared to HSS-ANC and general population level surveys at various geographic levels in the states of Karnataka, Maharashtra and Andhra Pradesh. Chi-square tests were used to ascertain statistical significance. PPTCT HIV prevalence was significantly lower than HSS-ANC HIV prevalence (0.92% vs. 1.22% in Andhra Pradesh, 0.65% vs. 0.89% in Karnataka, 0.52% vs. 0.60% in Maharashtra, p<0.001 for all three states). In all three states, HIV prevalence from PPTCT centres that were part of the sentinel surveillance was comparable to HSS-ANC prevalence but significantly higher than PPTCT centres that were not part of the sentinel surveillance. HIV prevalence from PPTCT data was comparable to that from general population surveys. In all three states, significant declines in HIV prevalence between 2007 and 2010 were observed with the PPTCT data set. District level analyses of HIV trends and sub-district level analysis of HIV prevalence were possible using the PPTCT and not the HSS-ANC data sets. CONCLUSION: HIV prevalence from PPTCT may be a better proxy for general population prevalence than HSS-ANC. PPTCT data allow for analysis of HIV prevalence and trends at smaller geographic units, which is important for decentralized planning of HIV/AIDS programming. With further improvements to the system, India could replace its HSS-ANC with PPTCT programme data for surveillance.

Relating the marginal fit of the castings to the accuracy of the impressions made from laminated hydrocolloid impression technique: a comparative study.

AIM: Relating the marginal fit of the castings, to the accuracy of the impression produced using laminated hydrocolloid impression technique, alginate and double-mixed polyvinyl siloxane. Basic objective of the study is to check the feasibility of the use of laminated hydrocolloid impression technique in the fixed partial denture. MATERIALS AND METHODS: The precisely machined metal die was designed to simulate standard complete metal crown preparation. The preparation was mounted on cylindrical base of 20 mm length and diameter of 10 mm. Seven impressions were made from the each impression material onto the metal die, and total 21 impressions were obtained from all three impression materials, which were poured by the die stone, and stone die was prepared. Wax patterns were fabricated on stone dies obtained from each impression and then casting was done. All the castings were checked for the marginal fit on metal die after applying a uniform standardized load of 30 pounds using measuring microscope. RESULTS: Result revealed that the marginal fit of the castings obtained from group II (laminated hydrocolloid technique) and group III (double-mix polyvinyl polysiloxane) did not show the significant difference between the two of them. Marginal gap of the castings obtained from group I are significantly greater in comparison to the castings obtained from groups II and III (p > 0.01). CONCLUSION: Group II (laminated hydrocolloid technique) impression material may be the choice of many clinicians over group III (double-mix polyvinyl polysiloxane) impression material. Group I (alginate impression material), though very cost-effective and easy to handle may not able to produce accurate results. CLINICAL SIGNIFICANCE: The study gives overview of the best impression material that can be used clinically. Laminated hydrocolloid technique is the technique of choice.