Abstract: A dental impression tray has an outwardly extending flange that is connected to posterior portions of a trough or channel for receiving a quantity of impression materials. The flange permits the tray to be firmly gripped on the sides of the channel in areas adjacent opposite posterior regions of the patient's dental arch, so that the cured impression material may be disengaged from the arch without excessive permanent distortion of the impression. Preferably, the flange extends along the entire perimeter of the channel and adjacent an occlusal portion of the channel.

Abstract: A process for the addition of compounds containing silicon-bonded hydrogen to compounds containing aliphatic unsaturation and compositions suitable for said process. The process is activated by visible radiation and is conducted in the presence of a platinum complex having one cyclopentadienyl group that is eta-bonded to the platinum atom and three aliphatic groups that are sigma-bonded to the platinum atom and a sensitizer that is capable of absorbing visible light and is capable of transferring energy to said platinum complex such that the hydrosilation reaction is initiated upon exposure to visible light. The invention also provides for use in the aforementioned process.

Abstract: A single phase aqueous solution containing water, a water-soluble film former (e.g., 2-hydroxyethylacrylate) and a salt of an acid (e.g., calcium trifluoroacetate) is used as a primer for adhering to or overcoating hard tissue such as tooth dentin.

Abstract: Organic fluoride sources comprising a tetrafluoroborate salt and capable of releasing fluoride ions into dentition in order to provide inhibition and/or prevention of dental caries are disclosed. A method of releasing fluoride ion into dental tissue is also disclosed.

Abstract: Coated abrasive binders made from a photocurable addition-polymerizable composition containing a free-radically-polymerizable monomer and a photoinitiator system containing (i) an arylidonium salt, (ii) a sensitizing compound, and (iii) an electron donor having an oxidation potential that is greater than zero and less than or equal to that of p-dimethyoxybenzene (1.32 volts vs. S.C.E.). The binders cure rapidly and deeply under ultraviolet or visible light, even when filled with large amounts of mineral grain or with coarse grades of minerals.

Abstract: Coated abrasive binders made from a photocurable addition-polymerizable composition containing a free-radically-polymerizable monomer and a photoinitiator system containing (i) an arylidonium salt, (ii) a sensitizing compound, and (iii) an electron donor having an oxidation potential that is greater than zero and less than or equal to that of p-dimethoxybenzene (1.32 volts vs. S.C.E.). The binders cure rapidly and deeply under ultraviolet or visible light, even when filled with large amounts of mineral grain or with coarse grades of minerals.

Abstract: An acid and a water-soluble film former are used as a primer for hard tissue (e.g., dentin). The acid has a pK.sub.a less than or equal to that of phenol and the acid and its calcium salt(s) are soluble in the film former. The primer is free of adhesively detrimental quantities of calcium salts that are not soluble in the film former.