Background: Poly lactic-co-glycolic acid (PLGA) has been widely investigated for various biomedical applications, such as craniofacial bone regeneration, wound dressing and tissue engineering. Electrospinning is a versatile technology used to produce micro/nanoscale fibers with large specific surface area and high porosity. Purpose: The aim of the current study is to prepare PLGA nanofibers using electrospinning for guided tissue regeneration/guided bone regeneration applications. The objective of this study is to determine the appropriate electrospinning parameters such as applied voltage, flow rate, spinneret-collector distance and polymer solution concentration for preparation of PLGA fibrous membrane and their effect on the mean fiber diameter of the electrospun fibers. Method: PLGA pellets were dissolved in Hexafluoroisopropanol (HFIP) in various concentrations overnight using a bench rocker. The resulting PLGA solution was then loaded into a syringe and electrospinning was done by maintaining the other parameters constant. Similarly, various fibrous mats were collected by altering the specific electrospinning parameter inputs such as applied voltage, flow rate and spinneret-collector distance. The morphology of the fibrous mats was characterized using Scanning Electron Microscope. The mean fiber diameter was assessed using ImageJ software and the results were compared using one-way ANOVA. Results: We obtained bead-free uniform fibers with various tested solution concentrations. One-way ANOVA analysis demonstrated significant variation in mean fiber diameter of the electrospun fibers with altering applied voltage, solution concentration, flow rate and spinneret-collector distance. Conclusion: The above-mentioned electrospinning parameters and solution concentration influence the mean fiber diameter of electrospun PLGA nanofibers.

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This study was performed as an adjunct to an existing clinical study to validate the effect of veneer: framework thickness ratio on stress distribution in an implant-supported all-ceramic fixed partial denture. Two commercially available titanium dental implants with corresponding customized abutments and a patient-retrieved all-ceramic fixed partial denture were scanned using a high-resolution micro-CT scanner. Reconstructed 3D objects, along with a simulated bone surface, were incorporated into a non-manifold assembly and meshed simultaneously using Simpleware software (Synopsys Simpleware ScanIP Version P-2019.09; Mountain View, CA). Three such volume meshes (Model A, Model B, Model C) corresponding to veneer: framework thickness ratios of 3:1, 1:1, and 1:3 respectively were created, and exported to a finite element analysis software (ABAQUS). An axial load of 110 N was applied uniformly on the occlusal surfaces to calculate the static stresses and contour plots were generated in the post-processing module. From the data obtained, we observed optimum stress distribution in Model B. Also, the tensile stresses were concentrated in the posterior connector region of the prosthesis in all three models tested. Within the limitations of this study, we can conclude that equal thickness of veneer and framework layers would aid in better stress distribution.

This study aimed to investigate four dental adhesive cements and develop a new method for constructing a bi-layered bone holder for implant testing. HahnTM Tapered Titanium Implants (Glidewell Laboratories) were embedded in mono- and bi-layered holders, and the implant components were assembled. First molar zirconia crowns and crowns for the tensile bond strength test were milled and sintered. Three self-adhesive resin cements (SARC) and one resin-modified glass ionomer (RMGI, Glidewell Laboratories) cement were used to cement the crowns on the abutment. Tensile bond strength, compressive load, and oblique load tests were performed on the implants. The Glidewell Experimental SARC (GES, Glidewell Laboratories) and RMGI cements had the highest tensile bond strength after thermocycling. The implant assemblies with these two cements had the highest mean compressive strength after thermocycling. Under oblique load, the implants with Denali (Glidewell Laboratories) and GES had the highest strength before thermocycling. However, after thermocycling, Dencem (Dentex) and RMGI had the highest strength under an oblique load. The GES cement and RMGI cement had a better overall performance with zirconia crowns and titanium abutments. In addition, a novel technique for constructing an artificial, bi-layered bone holder was successfully developed to mimic the natural structure of the jawbone.