ABSTRACT
Large oral bone defects require grafting of bone blocks rather than granules to give physically robust, biocompatible and osteoconductive regeneration. Bovine bone is widely accepted as a source of clinically appropriate xenograft material. However, the manufacturing process often results in both reduced mechanical strength and biological compatibility. The aim of this study was to assess bovine bone blocks at different sintering temperatures and measure the effects on mechanical properties and biocompatibility. Bone blocks were divided into four groups; Group 1: Control (Untreated); Group 2: Initial boil for 6 h; Group 3: Boil 6 h followed by sintering at 550 °C for 6 h; Group 4: Boil 6 h followed by sintering at 1100 °C for 6 h. Samples were assessed for their purity, crystallinity, mechanical strength, surface morphology, chemical composition, biocompatibility and clinical handling properties. Statistical analysis was performed using one-way ANOVA and post-hoc Tukey's tests for normally distributed and Friedman test for abnormally distributed quantitative data from compression tests and PrestoBlue™ metabolic activity tests. The threshold for statistical significance was set at p < 0.05. The results showed that higher temperature sintering (Group 4) removed all organic material (0.02% organic components and 0.02% residual organic components remained) and increased crystallinity (95.33%) compared to Groups 1-3. All test groups (Group 2-4) showed decreased mechanical strength (MPa: 4.21 ± 1.97, 3.07 ± 1.21, 5.14 ± 1.86, respectively) compared with raw bone (Group 1) (MPa: 23.22 ± 5.24, p <0.05), with micro-cracks seen under SEM in Groups 3 and 4. Group 4 had the highest biocompatibility (p < 0.05) with osteoblasts as compared to Group 3 at all time points in vitro. Clinical handling tests indicated that Group 4 samples could better withstand drilling and screw placement but still demonstrated brittleness compared to Group 1. Hence, bovine bone blocks sintered at 1100 °C for 6 h resulted in highly pure bone with acceptable mechanical strength and clinical handling, suggesting it is a viable option as a block grafting material.
ABSTRACT
BACKGROUND: Initiatives taken over the last few years have led us to the day when most of the medical and dental institutions in the developed countries have established a strong research culture at undergraduate level but the situation is quite the contrary in Pakistan. This study was carried out to investigate the current trends in undergraduate medical and dental research and to highlight the research barriers. METHODS: A cross-sectional study was conducted at six medical and dental colleges of Rawalpindi and Islamabad. A structured questionnaire was used to collect data from 300 students. Results were recorded as percentages. Findings of current survey were compared with those of already reported in literature using chi-square test. RESULTS: Out of 300 students, 206 (68.7%) students had already participated in research as principal researcher, co-researcher or as a research volunteer. Internet was most effective method of publicity of research opportunities reported by 74% of students. Only 36.7% students reported the presence of student research office at their institute. Accessibility to medical and dental journals and availability of research funds were reported by 77.2% and 13.4% of students, respectively. Lack of funding and academic overload were two main research barriers reported by 92.6% and 91.9% of students, respectively. CONCLUSION: The fraction of medical and dental students who are confident that they can plan, conduct and write a research study has increased over last four years. There is an improvement in the availability of research promoting activities but the number of research barriers is still high.
