ABSTRACT
The purpose of this study was to compare the properties of 2 new dual-cure, bulk-fill restorative composite resins to those of a hybrid composite resin material. Depth of cure, fracture toughness, porosity, microleakage, and volumetric shrinkage properties were examined. With the exception of fracture toughness, significant differences were found among materials. Compared to the incrementally placed hybrid composite, the dual-cure, bulk-fill restorative composites in self-cured mode had unlimited depth of cure, similar fracture toughness and porosity formation, and greater polymerization shrinkage and microleakage.
Subject(s)
Composite Resins/therapeutic use , Dental Restoration, Permanent/methods , Composite Resins/chemistry , Curing Lights, Dental , Dental Leakage/etiology , Hardness , Humans , In Vitro Techniques , PorosityABSTRACT
The mechanical properties of pulp-capping materials may affect their resistance to fracture during placement of a final restorative material or while supporting an overlying restoration over time. The purpose of this study was to compare the compressive strength, flexural strength, and flexural modulus of 2 new pulp-capping materials (TheraCal LC and Biodentine), mineral trioxide aggregate (MTA), and calcium hydroxide over time. Specimens were created in molds and tested to failure in a universal testing machine after 15 minutes, 3 hours, and 24 hours. The MTA specimens did not set at 15 minutes. At all time periods, TheraCal LC had the greatest compressive and flexural strengths. After 3 and 24 hours, Biodentine had the greatest flexural modulus. TheraCal LC had greater early strength to potentially resist fracture during immediate placement of a final restorative material. Biodentine had greater stiffness after 3 hours to potentially provide better support of an overlying restoration under function over time.
Subject(s)
Pulp Capping and Pulpectomy Agents/chemistry , Aluminum Compounds/chemistry , Aluminum Compounds/therapeutic use , Calcium Compounds/chemistry , Calcium Compounds/therapeutic use , Compressive Strength , Dental Stress Analysis , Drug Combinations , Humans , Oxides/chemistry , Oxides/therapeutic use , Pulp Capping and Pulpectomy Agents/therapeutic use , Silicates/chemistry , Silicates/therapeutic use , Tensile StrengthABSTRACT
This study evaluated the shear-bond strength of a resin-modified glass ionomer (RMGI) restorative material to a new silorane-based composite and a methacrylate-based composite in a sandwich technique with various combinations of surface treatments and bonding agents. Two composites, 2 bonding agents and 4 surface preparations were used to create 16 groups with 10 specimens each. After 24 hours storage at 37°C in 100% humidity, the specimens were tested for shear bond strength; means and standard deviations were determined per group. Surface modifications did not affect the shear-bond strength of the silorane or methacrylate composites to the RMGI. The new silorane composite had significantly lower bond strength to the RMGI compared to the methacrylate composite. The new silorane system adhesive agent had significantly higher bond strength to the RMGI compared to the methacrylate adhesive agent. The greatest bond strengths to the RMGI were produced when using the silorane system adhesive agent with the methacrylate composite.
Subject(s)
Acrylic Resins , Methacrylates/chemistry , Resins, Synthetic , Shear Strength , Silicon Dioxide , Silorane Resins/chemistryABSTRACT
A method for using PTFE tape as a matrix to prevent the etching and/or bonding of adjacent tooth structure was presented. This technique is simple, quick and inexpensive. PFTE tape in the form of plumber's tape is readily available at any hardware store. Despite manufacturers' varying thicknesses of PTFE tape, it can be stretched, yielding a matrix thinner than other matrix systems. The tape will also adhere and conform to adjacent tooth structure, offering the operator an unhindered access to perform sculpting of the restorative material.
