PubMed Health⌕ Search

PubMed · 11763922

Exploring beyond methacrylates.

Abstract

PURPOSE: This article focuses on the polymerization shrinkage of current dental composites as their major disadvantage and to find new routes for a solution. MATERIALS AND METHODS: A brief introduction describes selected methods for the shrinkage determination as well as some principal solutions to overcome the shrinkage problem. RESULTS: Siloranes, a new class of ring opening monomers, are presented as a promising resin matrix for dental composites. The synthesis of these monomers, and further consequences of the new chemistry for the formulation are discussed. Two selected silorane composites are presented with their mechanical data and their volume shrinkage.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

R Guggenberger, W Weinmann. 2000. Exploring beyond methacrylates.. https://pubmed.ncbi.nlm.nih.gov/11763922/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Composite indirect-direct method for fabricating multiple-unit provisional restorations.

This article describes a method for fabricating multiple-unit provisional restorations by use of the indirect-direct method without the need for abutment preparation on diagnostic casts. Composite is used with fiber reinforcement to create a provisional shell in a vinyl polysiloxane matrix. This method reduces chair time, as well as laboratory time required to fabricate provisional restorations. Control of restoration contours and incisal edge position is also enhanced.

Bisphenol A-Glycidyl Methacrylate↗

Adhesive phase separation at the dentin interface under wet bonding conditions.

Under in vivo conditions, there is little control over the amount of water left on the tooth and, thus, there is the danger of leaving the dentin surface so wet that the bonding resin undergoes physical separation into hydrophobic and hydrophilic-rich phases. The purpose of this study was to investigate phase separation in 2,2-bis[4(2-hydroxy-3-methacryloyloxy-propyloxy)-phenyl] propane (BisGMA)-based adhesive using molecular microanalysis and to examine the effect of phase separation on the structural characteristics of the hybrid layer. Model BisGMA/HEMA (hydroxyethl methacrylate) mixtures with/without ethanol and commercial BisGMA-based adhesive (Single Bond) were combined with water at concentrations from 0 to 50 vol%. Macrophase separation in the BisGMA/HEMA/water mixtures was detected using cloud point measurements. In parallel with these measurements, the BisGMA/HEMA and adhesive/water mixtures were cast as films and polymerized. Molecular structure was recorded from the distinct features in the phase-separated adhesive using confocal Raman microspectroscopy (CRM). Human dentin specimens treated with Single Bond were analyzed with scanning electron microscopy (SEM) and CRM mapping across the dentin/adhesive interface. The model BisGMA/HEMA mixtures with ethanol and the commercial BisGMA-based adhesive experienced phase separation at approximately 25 vol% water. Raman spectra collected from the phase-separated adhesive indicated that the composition of the particles and surrounding matrix material was primarily BisGMA and HEMA, respectively. Based on SEM analysis, there was substantial porosity at the adhesive interface with dentin. Micro-Raman spectral analysis of the dentin/adhesive interface indicates that the contribution from the BisGMA component decreases by nearly 50% within the first micrometer. The morphologic results in corroboration with the spectroscopic data suggest that as a result of adhesive phase separation the hybrid layer is not an impervious 3-dimensional collagen/polymer network but a porous web characterized by hydrophobic BisGMA-rich particles distributed in a hydrophilic HEMA-rich matrix.

Bisphenol A-Glycidyl Methacrylate↗

Dyes for caries detection: influence on composite and compomer microleakage.

The aim of this study was to evaluate the influence of caries-detecting dyes on the microleakage of adhesive materials. Sixty cubic class V cavities were prepared on buccal and lingual surfaces of 30 human third molars. Coronal margins were located in enamel and gingival margins in cementum. The teeth were randomly divided into six groups of ten restorations each. Cavities were restored with an adhesive system (Single Bond, 3M ESPE, St. Paul, Minn., USA), a compomer (F2000, 3M ESPE), or a composite resin (Z100, 3M ESPE) according to the manufacturer's directions. Acid red dye (Seek, Ultradent, South Jordan, Ut., USA) and basic fuchsin dye (Vide Cárie, Inodon, Porto Alegre, Brazil) were tested. Control groups were prepared without the use of dyes. After 7 days of storage in distilled water, the restorations were polished and the teeth were subjected to thermal cycling followed by immersion in 2% methylene blue. The teeth were sectioned, and microleakage scores were evaluated under magnification (40x). Data were submitted to statistical analysis using the nonparametric Kruskal-Wallis test. A statistically significant difference ( P<0.05) in microleakage was found between the materials in cementum (Z100>F2000) but not in enamel. Control and experimental groups using dyes showed similar results. It was concluded that dyes for caries detection did not increase microleakage of the adhesive materials tested.

Bisphenol A-Glycidyl Methacrylate↗