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Microwave‐cured acrylic resins and silicone–gypsum moulding technique
Author(s) -
Del Bel Cury A. A.,
Rached R. Nunes,
Ganzarolli S. Maria
Publication year - 2001
Publication title -
journal of oral rehabilitation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 93
eISSN - 1365-2842
pISSN - 0305-182X
DOI - 10.1046/j.1365-2842.2001.00684.x
Subject(s) - knoop hardness test , gypsum , nuclear chemistry , acrylic resin , silicone , materials science , composite material , chemistry , indentation hardness , microstructure , coating
This study evaluated the residual monomer (RM), Knoop hardness (KHN) and transverse strength (TS) of two microwave‐cured acrylic resins (Acron MC ® (A), GC Dent. Ind. Corp., Tokyo, Japan and Onda Cryl ® (O), AO Classico Ltda, São Paulo, Brazil) when processed with an all‐type III gypsum moulding technique (G) or a silicone–gypsum moulding technique (S). One hundred and forty four specimens were fabricated and equally distributed into four groups (AG, AS, OG and OS). The TS tests were conducted after 48 h of water storage, and KHN values were obtained after 24, 48, 72 h and 30 days. The RM was determined every 24 or 48 h over a period of 288 h. The acrylic resins were prepared and processed according to the manufacturer’s directions. Both AS and OS showed the highest means ( P < 0·05) for RM (μg cm –2 ) only after 24 h (AS = 56·84 ± 27·39/AG = 7·51 ± 5·75/OS = 3·59 ± 1·60/OG = 1·02 ± 0·3), 48 h (AS = 28·99 ± 9·35/AG = 2·65 ± 2·17/OS = 2·37 ± 0·84/OG = 0·68 ± 0·49) and 72 h (AS = 15·98 ± 9·01/AG = 1·40 ± 0·57/OS = 1·87 ± 0·52/OG = 0·75 ± 0·44). Both AS and OS showed the highest means ( P < 0·02) for KH after 24 h (AS = 18·69 ± 2·3/AG = 17·79 ± 0·7/OS = 18·41 ± 1·0/OG = 16·04 ± 0·6). After 48 h the mean values for OS and OG differed significantly ( P < 0·03) (OS = 18·67 ± 0·8/OG = 16·75 ± 0·8). No differences of KHN were found among the groups during the storage periods. The TS values for A and O were not affected by either G or S ( P > 0·05). Silicone–gypsum mould technique affected the RM and KHN of the resins in the first 2 and 5 days of analysis, respectively. The type of mould did not affect TS, and the acrylic resins differed from each other for all properties regardless of the type of mould.