Dimensional stability of complete denture permanent acrylic resin denture bases; A comparison of dimensions before and after a second curing cycle.

The purpose of this study was to measure deformation of mandibular complete denture permanent bases after secondary curing. A cast of a flat mandibular edentulous ridge was duplicated ten times. A wax base was laid on the original cast, two wax sprues were attached and an overcast was made.

Effect of GC METALPRIMER II on bond strength of heat-cured acrylic resin to titanium alloy (Ti-6Al-4V) with two different surface treatments.

This study investigated the bond strength of heat-polymerized acrylic resin to titanium alloy using a proprietary bonding agent (GC Metalprimer II). Two surface treatments (sandblasted or roughened with a tungsten carbide bur) were compared for their effect on bond strength with or without thermal cycling. Eighty specimens of heat-polymerized acrylic resin bonded to titanium alloy (Ti-6Al-4V) were prepared: 20 specimens (control) and 60 used a bonding agent.

Surface roughness of impression materials and dental stones scanned by non-contacting laser profilometry.

Objective: To analyze differences in the way dental materials digitize on a non-contacting laser profilometer (NCLP).

Methods: Three Type IV dental stones and 15 impression materials were mixed according to the manufacturer's instructions and expressed against a glass block to record its surface characteristics. From each material an area of 6 x 40 mm was scanned on the NCLP and the Ra, Rq and Rt roughness values measured from 20 randomly selected transverse profiles.

The constitution, physical properties and biocompatibility of modified accelerated cement.

Objectives: The aim of this study was to determine constitution and physical properties of a prototype material based on Portland cement and assess biocompatibility compared with glass-ionomer cement by evaluating cell morphology.

Materials And Methods: Analysis of the material was performed using energy dispersive analysis (EDAX) and X-ray diffraction (XRD) analysis. Compressive strength and the effect of changing the mixing and curing conditions on the compressive strength of the materials were evaluated.

Deformation of phosphate-bonded investment materials at elevated temperatures.

Objectives: To determine deformation in phosphate-bonded investment (PBI) materials for "in-service conditions" and to investigate the influence of air bubble pores on deformation at 900 degrees C.

Methods: Surviving high and low strain-rate disc-rupture strength test samples were assessed for deformation. A dental centrifugal casting machine and a dental superplastic-forming machine were used to apply the loads.

Characterization of Portland cement for use as a dental restorative material.

Objectives: The aim of this study was to evaluate the suitability of fast-setting cement formulations based on Portland cement as dental core build-up materials using two different methods of testing compressive strength and evaluation of setting times.

Methods: Four fast-setting cements based on Portland cement and their four respective densified with small particle (DSP) mortars were tested for setting time, constitution of cement by EDAX, and compressive strength using International and British Standards. Ordinary Portland cement (OPC) was used as a control.

The constitution of mineral trioxide aggregate.

Objectives: The aim of this study was to determine the constitution of a commercially available root-end filling material, mineral trioxide aggregate, (MTA) (ProRoot MTA, Tulsa Dental, Tulsa, OK, USA). The surface morphology of the material with various treatment conditions was also evaluated.

Methods: The constitution of two commercial versions of MTA was determined before and after mixing with water.

Optimisation of the superplastic forming of a dental implant for bone augmentation using finite element simulations.

Objectives: The phenomenon of superplasticity has made it possible to form complex shapes that require extremely high degrees of ductility in titanium alloy with minimal internal stresses. Combined with the use of an investment casting material as the die material, which makes possible the forming of re-entrant angles, it is possible to produce membranes for ridge augmentation. The aim is to characterise the metal alloy sheet and simulate the superplastic forming process in three dimensions to produce process parameters, namely gas pressure as a function of time, to accurately adapt the titanium sheet to the bone surface.

Sensitivity of a disc rupture strength test to air bubble pores in phosphate-bonded investment materials at elevated temperatures.

Objectives: To investigate the sensitivity of a modified disc rupture test to variables affecting the strength of four phosphate-bonded investment materials under conditions closely resembling the in-service environment. This study examined the influence of air bubble pores on the strength of phosphate bonded investment materials at a temperature of 900 degrees C.

Methods: A modified disc rupture configuration was used to test a circular investment diaphragm with clamped edges, in tension, initiated by bending.