Abstract: The invention relates to denture-supporting permanent magnet assemblies each using a magnetic attractive force, and provides denture-supporting permanent magnet assemblies, denture-supporting keepers, and denture-supporting magnetic attachments each of which uses a magnetic material with a high saturation magnetic flux density, i.e., a magnetic material comprising 15.5-18.5 wt % Cr and balance Fe as magnetic materials used for the permanent magnet assembly and the keeper in order to provide a magnetic attachment which keeps an excellent attractive force even if miniaturized.

Abstract: A permanent magnet assembly for stably fixing a denture comprising a permanent magnet, a casing made of a corrosion-resistant, magnetic material having a cavity for receiving the permanent magnet, and a seal plate for covering an opening of the casing to prevent the permanent magnet from exposing outside, the seal plate consisting of a seal ring member made of a corrosion-resistant, non-magnetic material and a disc plate made of a corrosion-resistant, soft-magnetic material and having substantially the same outer diameter as the inner diameter of the seal ring member, the seal ring member and the disc plate being concentrically arranged in the same plane, the disc plate being welded to the seal ring member in their abutment, and the seal ring member being welded to the casing. Laser welding is utilized.

Abstract: A light shielding screen structure comprising a first light transmissible substrate, a second light transmissible substrate and, interposed therebetween, a light shielding screen comprising a perforated structure comprising a plurality of fine partition walls and apertures defined by said partition walls, said first and second light transmissible substrates being connected respectively to both end surfaces of the parition walls of the light shielding screen through a photocured adhesive layer. The screen structure exhibits a peeling strength of 50 g/cm or more at the connection between each partition wall and each light transmissible substrate and includes a fillet of not greater than 5 .mu.m in width in each aperture at a corner portion defined by the inner wall of each aperture and the inner surface of each light transmissible substrate.

Abstract: A dental amalgam alloy containing selenium includes one or two or more of powders of chemically synthesized copper selenides (CuSe, Cu.sub.2 Se), silver selenide (Ag.sub.2 Se), gold selenide (Au.sub.2 Se.sub.3), nickel selenide (NiSe), palladium selenides (PdSe, PdSe.sub.2), platinum selenides (PtSe.sub.2, PtSe.sub.3), zinc selenide (ZnSe), mercury selenide (HgSe), indium selenide (In.sub.2 Se.sub.3) and tin selenide (SnSe) added to and mixed with a dental amalgam alloy powder with the resulting powder mixture containing selenium regulated to an amount of 0.05 to 5 weight %.

Abstract: Selenium-containing amalgam alloys for dental restoration comprises 0.1-50% by weight of any one of the following alloy powders (A), (B) and (C) mixed with 50-99.9% by weight of the following amalgam alloy powders (D).(A): Silver alloy powders containing no less than 50% by weight of silver and 0.01-10% by weight of selenium,(B): Copper alloy powders containing no less than 50% by weight of copper and 0.01-5% by weight of selenium,(C): Alloy powders mix of (A) with (B) wherein the total amount of silver and copper is adjusted to no less than 50% by weight, and the amount of selenium to 0.01-10% by weight, and(D): Silver-tin-copper amalgam alloy powders.At least one of the any one of (A), (B) and (C) and (D) may be pre-amalgamated with mercury in an amount of no higher than 3% by weight based on the total weight thereof.

Abstract: Selenium-containing amalgam alloys for dental restoration comprises 0.1-50% by weight of any one of the following alloy powders (A), (B) and (C) mixed with 50-99.9% by weight of the following amalgam alloy powders (D).(A): Silver alloy powders containing no less than 50% by weight of silver and 0.01-10% by weight of selenium,(B): Copper alloy powders containing no less than 50% by weight of copper and 0.01-5% by weight of selenium,(C): Alloy powders mix of (A) with (B) wherein the total amount of silver and copper is adjusted to no less than 50% by weight, and the amount of selenium to 0.01-10% by weight, and(D): Silver-tin-copper amalgam alloy powders. At least one of the any one of (A), (B) and (C) and (D) may be pre-amalgamated with mercury in an amount of no higher than 3% by weight based on the total weight thereof.

Abstract: A novel setting composition for dental purposes comprises a dental silver amalgam alloy composed mainly of silver and tin, and including one or more of copper, zinc, indium, palladium and gold; mercury in an amount sufficient to amalgamate said alloy: and selenium. The selenium may or may not be coated with a metal showing an affinity for mercury, such as silver. The amount of selenium contained is in a range of 0.005 to 5% by weight.

Abstract: A process for producing a 3-iminohaloisoindoline-1-one which comprises treating a halophthalodinitrile with ammonia and/or an organic amine together with hydrogen peroxide in a mixed reaction medium comprising water and an organic solvent.