title: Scratch hardness of stone models--measuring conditions.
abstract: This study investigated the effects of scratch load, scratch speed, and storage period of specimen on the scratch hardness of stone models. Types 4 and 5 stone specimens were made from vinyl silicone rubber and alginate impressions respectively. After specimens were stored in a desiccator with silica gel at room temperature for 24 hours or 1 week, scratches were created on the surface with three different scratch loads (1N, 2N, and 3N) and two different scratch speeds (50 and 100 mm/min). Then, the depths of scratches were measured. Scratch depth of stone specimens increased with increasing scratch load. Scratch depths of Type 4 stone specimens after 1-week storage were smaller than those after 24-hour storage at a speed of 100 mm/min. However, the effect of scratch speed on scratch depth did not follow a specific trend.
authors.affiliation: Dental Research Center, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan. nakagawa@dent.nihon-u.ac.jp
authors.forename: Hisami
authors.initials: H
authors.lastname: Nakagawa
authors.forename: Hisako
authors.initials: H
authors.lastname: Hiraguchi
mesh_terms: D000464:Alginates; D000704:Analysis of Variance; D002133:Calcium Sulfate; D003760:Dental Impression Materials; D003799:Dental Stress Analysis; D006244:Hardness; D006245:Hardness Tests; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D003765:Models, Dental; D012826:Silicone Elastomers; D018709:Statistics, Nonparametric; D013499:Surface Properties
chemical_list: D000464:Alginates; D003760:Dental Impression Materials; D012826:Silicone Elastomers; D002133:Calcium Sulfate