METHODS: Forty direct impressions of a mandibular reference model fitted with six dental implants and multibase abutments were made using VPES and PE, and implant casts were poured (N = 20). The VPES and PE groups were split into four subgroups of five each, based on splinting type: (a) no splinting; (b) bite registration polyether; (c) bite registration addition silicone; and (d) autopolymerizing acrylic resin. The accuracy of implant-abutment replica positions was calculated on the experimental casts, in terms of interimplant distances in the x, y, and z-axes, using a coordinate measuring machine; values were compared with those measured on the reference model. Data were analyzed using non-parametrical Kruskal-Wallis and Mann-Whitney tests at α = .05.
RESULTS: The differences between the two impression materials, VPES and PE, regardless of splinting type, were not statistically significant (P>.05). Non-splinting and splinting groups were also not significantly different for both PE and VPES (P>.05).
CONCLUSIONS: The accuracy of VPES impression material seemed comparable with PE for multi-implant abutment-level impressions. Splinting had no effect on the accuracy of implant impressions.
MATERIALS AND METHODS: In this study, we focus on two important drugs used for TB treatment - rifampicin (RIF) and isoniazid (INH) - and report a detailed study of RIF-loaded poly lactic-co-glycolic acid (PLGA) NPs and INH modified as INH benz-hydrazone (IH2) which gives the same therapeutic effect as INH but is more stable and enhances the drug loading in PLGA NPs by 15-fold compared to INH. The optimized formulation was characterized using particle size analyzer, scanning electron microscopy and transmission electron microscopy. The drug release from NPs and stability of drug were tested in different pH conditions.
RESULTS: It was found that RIF and IH2 loaded in NPs release in a slow and sustained manner over a period of 1 month and they are more stable in NPs formulation compared to the free form. RIF- and IH2-loaded NPs were tested for antimicrobial susceptibility against Mycobacterium tuberculosis H37Rv strain. RIF loaded in PLGA NPs consistently inhibited the growth at 70% of the minimum inhibitory concentration (MIC) of pure RIF (MIC level 1 µg/mL), and pure IH2 and IH2-loaded NPs showed inhibition at MIC equivalent to the MIC of INH (0.1 µg/mL).
CONCLUSION: These results show that NP formulations will improve the efficacy of drug delivery for TB treatment.