In vitro study on the dimensional changes of human dentine after demineralization.
Dentine rods measuring approximately 0.7 x 0.7 x 5.0 mm were prepared from dentine of extracted human third molars stored in saline containing 0.5% sodium azide at 4 degrees C until used. Forty specimens were demineralized in 10% citric acid plus 3% ferric chloride (w/w) solution for 8 h, then assigned to four groups (A, B, C and D) of 10 specimens each. Groups A and B were used to investigate volumetric changes after air-drying and further immersion in either water, an aqueous solution of 50% 2-hydroxymethylmethacrylate (HEMA) or 100% HEMA, followed by air-drying. Groups C and D were used to investigate the ability of 100% HEMA or 100% ethylene glycol to prevent shrinkage of demineralized dentine during exposure to air. Demineralization caused a small, non-significant (1.9%) reduction in dentine volume. Air-drying further reduced the volume by 65.6%. When demineralized, shrunken specimens were immersed in water for 24 h, they recovered their original demineralized volume. Immersion in 100% HEMA did not re-expand demineralized shrunken dentine. Specimens immersed in 50% HEMA yielded a 50% volume shrinkage when exposed to air for 24 h. Both 100% HEMA and 100% ethylene glycol were effective in preventing shrinkage of demineralized dentine. The technique used provided useful information about maximal dimensional changes that may occur at a microscopic level during adhesive dental restorative procedures.
Carvalho
R M
RM
Department of Operative Dentistry, Bauru School of Dentistry, University of Sao Paulo, Brazil.
Yoshiyama
M
M
Pashley
E L
EL
Pashley
D H
DH
D000134:Acid Etching, Dental / Q000009:adverse effects*; D002951:Citrates / Q000494:pharmacology; D019343:Citric Acid; D003804:Dentin / Q000737:chemistry* / Q000187:drug effects; D019855:Ethylene Glycol; D005026:Ethylene Glycols / Q000737:chemistry; D006801:Humans; D007101:Immersion; D008689:Methacrylates / Q000737:chemistry; D017001:Tooth Demineralization / Q000139:chemically induced*; D014867:Water / Q000737:chemistry; D017155:Wettability
D002951:Citrates; D005026:Ethylene Glycols; D008689:Methacrylates; D014867:Water; D019343:Citric Acid; C005044:hydroxyethyl methacrylate; D019855:Ethylene Glycol