INTRODUCTION Whitening toothpastes which have been accepted in populations may affect properties of enamel and restorative materials. The aim of this study was to compare the microhardness of human enamel and Z250 microhybrid composite resin after brushing with two whitening toothpastes. MATERIALS AND METHODS In this experimental study of enamel specimens, forty five freshly extracted human i...

statement of problem: the restoration of the teeth should have enough ability to withstand masticator forces while preserving as much tooth structure as possible. purpose: the purpose of this study was to compare the effects of light-heat cured composite with light cured composite restorations on fracture resistance of the restored teeth. materials and methods: forty healthy maxillary premolar ...

Aim of this research is the vibration analysis and control of rotating composite thin-walled beam containing distributed piezoelectric sensors and actuators. The formulation is based on thin-walled, single cell composite beam including the warping function, centrifugal force, Coriolis acceleration and piezoelectric effect. Adaptive capability of thin-walled beam is obtained by PVDF sensor and p...

AIMS AND OBJECTIVES Satisfactory composite restoration depends upon its smooth finish, quality of polishing agents, type of composite material used, and its composition. The present study evaluated the effect of different polishing systems on the surface roughness of composite resin. MATERIALS AND METHODS Forty discs of composite were prepared and equally subjected to different finishing and ...

Introduction: Bleaching of discolored tooth may affect the tooth/composite interface. The aim of this study was to evaluate the effect of different concentrations of carbamide peroxide (CP) on the marginal seal of composite restorations bonded with a self-etch adhesive. Materials and Methods: In this experimental study  Class V cavities were prepared on the buccal and lingual surfaces o...

Temperature control is the key to effective resistive heating for composite rigidization. The ability to monitor and even control the temperature provides an active control strategy in prescribing and predicting the stiffness of the hardened composite. Further, understanding how the material responds to an electrical input determines both the type of control to be used as well as the level of c...

The dynamic output feedback decentralized H∞ control and the reliability of the designed system (the maximal number of control-channel outages when the performance is still acceptable) is studied for symmetric composite systems. It is shown that the decentralized H∞ control problem can be simplified to a simultaneous H∞ control problem for two modified subsystems. A design method based on the s...

This paper presents a solution to the boundary stabilization of a symmetric composite laminated plate in free transverse vibration. The symmetric composite laminated plate dynamics is presented by a linear fourth order partial differential equation (PDE). A linear control law is constructed to stabilize the plate. The control force consists of feedback of the velocity at the boundary of the pla...

statement of the problem: porcelain may fracture or chip if exposed to any traumas and can be repaired by using a resin composite. purpose: this study was aimed to evaluate the influences of er:yag laser on shear bond strength (sbs) of resin composite to feldspathic porcelain. materials and method: seventy-two porcelain blocks were divided into six groups (n=12): g1: no treatment (control group...

objectives: color change of composite restorations is well known to dentists. however, the effect of commonly consumed drinks on discoloration of composite resins has yet to be determined. this study sought to assess the color change of a nanofilled (premise) and a flowable composite resin (premise flowable) following simulated consumption of tea, cola, iron drops and multivitamin syrup. materi...