Correlation of ultrasound microscopy and Vickers hardness measurements of human dentin and enamel - A pilot study.

Objective: To investigate if Vickers microhardness of dentin and enamel correlated with acoustic velocity c(l) or acoustic reflection from the sample's top (amplitude).

Methods: Eight transversal sections of a sound human tooth were investigated with scanning acoustic microscopy (SAM) and Vickers microhardness measurements. Longitudinal acoustic velocity c(l), amplitude and microhardness MHV were evaluated and for each c(l) test point corresponding amplitude and MHV were linearly interpolated and graphically analyzed.

Contact angle and surface free energy of experimental resin-based dental restorative materials after chewing simulation.

Objective: To investigate contact angle and surface free energy of experimental dental resin composites containing novel delivery systems of polymeric hollow beads and low-surface tension agents after chewing simulation test.

Methods: A delivery system of novel polymeric hollow beads differently loaded with two low-surface tension agents was used in different amounts to modify commonly formulated experimental dental resin composites. The non-modified resin was used as standard.

Bacterial viability and physical properties of antibacterially modified experimental dental resin composites.

Purpose: To investigate the antibacterial effect and the effect on the material properties of a novel delivery system with Irgasan as active agent and methacrylated polymerizable Irgasan when added to experimental dental resin composites.

Materials And Methods: A delivery system based on novel polymeric hollow beads, loaded with Irgasan and methacrylated polymerizable Irgasan as active agents were used to manufacture three commonly formulated experimental resin composites. The non-modified resin was used as standard (ST).

Shear bond strength and fracture analysis of human vs. bovine teeth.

Purpose: To evaluate if bovine enamel and dentin are appropriate substitutes for the respective human hard tooth tissues to test shear bond strength (SBS) and fracture analysis.

Materials And Methods: 80 sound and caries-free human erupted third molars and 80 freshly extracted bovine permanent central incisors (10 specimens for each group) were used to investigate enamel and dentine adhesion of one 2-step self-etch (SE) and one 3-step etch and rinse (E&R) product. To test SBS the buccal or labial areas were ground plane to obtain appropriate enamel or dentine areas.

Bacterial viability on surface-modified resin-based dental restorative materials.

Unlabelled: The purpose of the present investigation was to investigate the viability of early colonizers on the surfaces of resin-based dental restorative materials modified with low-surface tension active agents in comparison with the unmodified material. A novel polymeric sorption material, loaded with two low-surface tension γ(L) active agents (hydroxyfunctional polydimethylsiloxane and polydimethylsiloxane) or a polymerizable active agent (silicone polyether acrylate), was used to modify commonly formulated experimental dental resin composites. The non-modified resin was used as the standard (ST).

A new approach to influence contact angle and surface free energy of resin-based dental restorative materials.

The purpose of the present study was to identify novel delivery systems and active agents which increase the water contact angle and reduce the surface free energy when added to resin-based dental restorative materials. Two delivery systems based on zeolite or novel polymeric hollow beads (Poly-Pore), loaded with two low surface tension active agents (hydroxy functional polydimethylsiloxane and polydimethylsiloxane) or a polymerizable active agent (silicone polyether acrylate) were used to modify commonly formulated experimental dental resin composites. The non-modified resin was used as a standard (ST).

Effect of Energy Density on the Physical Properties of Resin-Based Restorative Materials when Polymerized with Quartz-Tungsten Halogen or LED-Light.

Objectives: The purpose of this study was to evaluate flexural strengths, moduli, and maximum deflection of Clearfil AP-X (APX) and Ceram-X Mono (CXM) when cured with a quartz-tungsten halogen (QTH) or an LED-light (LED).

Methods: Specimens were made according to ISO 4049 and cured with QTH or LED for 10, 20 or 60s. Flexural strength, modulus, and deflection were determined after 24 h water storage at 37 degrees C and after thermocycling.

Physical properties of self-, dual-, and light-cured direct core materials.

The objective of this study is to evaluate flexural strength, flexural modulus, compressive strength, curing temperature, curing depth, volumetric shrinkage, water sorption, and hygroscopic expansion of two self-, three dual-, and three light-curing resin-based core materials. Flexural strength and water sorption were measured according to ISO 4049, flexural modulus, compressive strength, curing temperature, and curing depth according to well-proven, literature-known methods, and the volumetric behavior was determined by the Archimedes' principle. ANOVA was calculated to find differences between the materials' properties, and correlation of water sorption and hygroscopic expansion was analysed according to Pearson (p < 0.

Impact of replacing Bis-GMA and TEGDMA by other commercially available monomers on the properties of resin-based composites.

Purpose: To evaluate important material properties of six experimental resin-based restorative materials (EXP) with systematically modified resin matrices using conventional and alternative monomers in comparison with an experimental standard (ST).

Materials And Methods: Commercially available monomers were selected according to their molecular weight, functionality, viscosity, and polymerization shrinkage. ST, 71wt% filler, matrix UDMA/Bis-GMA/TTEGDMA and six EXPs with modified organic matrices but the same filler content were manufactured.

Effect of exposure time on the color stability of resin-based restorative materials when polymerized with quartz-tungsten halogen and LED light.

The objective of this study was to investigate the effect of exposure time on color stability of resin-based restorative materials when polymerized with quartz-tungsten halogen light (QTH) or light-emitting diode light (LED). Eight samples of Ceram-X Mono, Dyract eXtra, and Tetric EvoCeram each were cured for 10, 20, and 60 s with QTH or LED. The CIE-Lab values (L*, a*, b*) were measured prior to and after performing water storage or a Suntest, and ΔL, Δa, Δb, and ΔE were calculated.

The effect of different bonding techniques on ceramic/ resin shear bond strength.

Purpose: To investigate the effect of different adhesives on the shear bond strength between a feldspathic machinable ceramic and a luting resin.

Materials And Methods: Seven groups of 20 ceramic specimens each were machined from Vita Mark II blocs. Their surfaces were uniformly treated with 1000-grit paper.

In vitro effect of light-emitting diode light polymerization on the color stability of three resin-based restorative materials.

Objective: To investigate the color stability of resin-based restorative materials when polymerized with light-emitting diode (LED) curing light in the constant or exponential mode.

Material And Methods: Eight specimens of Admira (AD), Compoglass F (CO), and Tetric EvoCeram (TE) constantly cured or exponentially cured with a high-powered LED curing light for 10, 20, or 60 s. The CIE-Lab values (L*, a*, b*) were measured prior to and after performing the water storage or color stability test according to EN ISO 7491 (Suntest).

Polymerization shrinkage and hygroscopic expansion of contemporary posterior resin-based filling materials--a comparative study.

Objectives: To investigate the polymerization shrinkage and hygroscopic expansion of contemporary posterior resin-based filling materials.

Methods: The densities of SureFil (SU), CeramXMono (CM), Clearfil AP-X (CF), Solitaire 2 (SO), TetricEvoCeram (TE), and Filtek P60 (FT) were measured using the Archimedes' principle prior to and 15min after curing for 20, 40 and 60s and after 1h, 24h, 7 d, and 30 d storage at 37 degrees C in water. Volumetric changes (DeltaV) in percent after polymerization and after each storage period in water were calculated from the changes of densities.

Preparation of the coronal and middle third of oval root canals with a rotary or an oscillating system.

Objectives: To comparatively evaluate the preparation of oval root canals with a rotary or an oscillating system.

Study Design: The middle and coronal parts of 55 extracted permanent teeth with oval canals were prepared using FlexMaster (FM) rotary NiTi instruments and EndoEze AET (EE) stainless steel oscillating instruments. Pre- and postoperative images of cross-sections were superimposed to identify shifts in the center and to assess the percentage of untreated regions.

Water sorption and solubility of contemporary resin-based filling materials.

Purpose: Evaluation of water sorption and solubility of contemporary resin-based filling materials.

Methods: Specimens of Herculite (HE), Point 4 (P4), TetricCeram (TC), Miris (MI), TetricCeram HB (HB), Solitaire 2 (SO), SureFil (SU), Definite (DE), Admira (AD), Dyract AP (DY), Compoglass F (CO), and TetricFlow (TF) were prepared according to ISO 4049. Water sorption and solubility were measured after water storage at 37 degrees C for 7 days.

Color stability of resin-based filling materials after aging when cured with plasma or halogen light.

The influence of curing devices and curing times on the color stability of filling resins was investigated by measuring the CIE-Laboratory-values after performing dry storage, water storage, and a Suntest (EN ISO 7491). Eight samples each of Charisma (CH), Durafill (DU), Definite (DE), and Dyract AP (DY) were light cured by using Translux Energy (TE) for 20, 40 or 60 s, or by using Apollo 95E (AP) for 3, 10 or 20 s. Minor color changes occurred for all dry stored materials, devices and curing times.

Color stability of resin matrix restorative materials as a function of the method of light activation.

The purpose was to investigate the influence of curing devices and curing times on the yellow value (b-value) of composites, ormocers and compomers after performing a suntest (EN ISO 7491). Eight samples of Charisma (CH), Durafill (DU), Definite (DE), and Dyract AP (DY) each were light cured with Translux Energy (tungsten halogen light) for 20, 40 or 60 s and with Apollo 95-E (plasma light) for 3, 10 or 20 s. All samples were subjected to a suntest.

Resin/Resin bonding: a new adhesive technology.

Purpose: Evaluation of a new surface treatment method to obtain a good bond strength between a luting composite and (1) a light-cured, (2) a heat-cured and (3) a thermoplastic resin.

Materials And Methods: Specimens were prepared and tests conducted according to ISO 10477, Amend. 1.