Synthesis and characterization of a photo-cross-linked bioactive polycaprolactone-based osteoconductive biocomposite.

In this study, a light cross-linkable biocomposite scaffold based on a photo-cross-linkable poly (propylene fumarate) (PPF)-co-polycaprolactone (PCL) tri-block copolymer was synthesized and characterized. The developed biodegradable scaffold was further modified with ß-tricalcium phosphate (ß-TCP) bioceramic for bone tissue engineering applications. The developed biocomposite was characterized using H nuclear magnetic resonance and Fourier transform infrared spectroscopy. Moreover, the bioceramic particle size distribution and morphology were evaluated using Brunauer-Emmett-Teller method, X-ray diffraction, and scanning electron microscopy. The mechanical properties and biodegradation of the scaffolds were also evaluated. Cytotoxicity and mineralization assays were performed to analyze the biocompatibility and bioactivity capacity of the developed biocomposite. The characterization data confirmed the development of a biodegradable and photo-cross-linkable PCL-based biocomposite reinforced with ß-TCP bioceramic. In vitro analyses demonstrated the biocompatibility and mineralization potential of the synthesized bioceramic. Altogether, the results of the present study suggest that the photo-cross-linkable PCL-PPF-PCL tri-block copolymer reinforced with ß-TCP is a promising biocomposite for bone tissue engineering applications. According to the results, this newly synthesized material has a proper chemical composition for further clinically-relevant studies in tissue engineering.

The effect of thermocycling on the degree of conversion and mechanical properties of a microhybrid dental resin composite.

OBJECTIVE: The purpose of this study was to investigate the degree of conversion (DC) and mechanical properties of a microhybrid Filtek Z250 (3M ESPE) resin composite after aging. METHOD: The specimens were fabricated using circular molds to investigate Vickers microhardness (Vickers hardness number [VHN]) and DC, and were prepared according to ISO 4049 for flexural strength testing. The initial DC (%) of discs was recorded using attenuated total reflectance-Fourier transforming infrared spectroscopy. The initial VHN of the specimens was measured using a microhardness tester under a load of 300 g for 15 seconds and the flexural strength test was carried out with a universal testing machine (crosshead speed, 0.5 mm/min). The specimens were then subjected to thermocycling in 5°C and 55°C water baths. Properties were assessed after 1,000-10,000 cycles of thermocycling. The surfaces were evaluated using scanning electron microscopy (SEM). Data were analyzed using 1-way analysis of variance followed by the Tukey honest significant difference post hoc test. RESULTS: Statistical analysis showed that DC tended to increase up to 4,000 cycles, with no significant changes. VHN and flexural strength values significantly decreased upon thermal cycling when compared to baseline (p < 0.05). However, there was no significant difference between initial and post-thermocycling VHN results at 1,000 cycles. SEM images after aging showed deteriorative changes in the resin composite surfaces. CONCLUSIONS: The Z250 microhybrid resin composite showed reduced surface microhardness and flexural strength and increased DC after thermocycling.

Oral health status of dialysis patients based on their renal dialysis history in Kerman, Iran.

PURPOSE: Maintaining a high level of periodontal and oral health in patients undergoing renal dialysis is of paramount importance because of the inherent compromised host defence mechanisms. The aim of the present study was to determine the periodontal status and the level of dental caries in renal dialysis patients in Kerman, Iran. MATERIALS AND METHODS: A cross-sectional study was conducted on two groups of patients: one including 68 renal dialysis patients (test) and the other including 30 healthy subjects (control). Half-mouth measurements of Gingival Index (GI), Plaque Index (PI), probing pocket depth (PPD), gingival recession (GR), clinical attachment level (CAL) and bleeding on probing (BOP) as well as decayed, missing or filled teeth (DMFT) index were recorded. RESULTS: The GI, BOP, PPD, CAL and GR were significantly greater among the test group as compared with the control group; however, the DMFT did not differ significantly among the groups. There was no relationship between the duration of the dialysis and the periodontal indices. CONCLUSIONS: It seems that patients with chronic renal failure have less favourable periodontal health than normal patients. The present study showed that oral home care practices were inadequate. Thus, preventive programmes to promote the oral health status of haemodialysis patients are needed.