[Bonding of resin cement to bleached dental enamel].
OBJECTIVE
The effects of bleaching times, types of etching agent and storage period of bleached bovine tooth on the shear bond strength of resin cement to the enamel were examined.


METHODS
Bovine teeth were repeatedly bleached 0, 1, 3, and 5 times then stored in 37 degrees C water for 1 week. The effect of bleaching number of the bovine tooth on the bond strength of resin cement to the enamel was investigated using 40% phosphoric acid (EG) etching technique. Next, the effects of types of etching agent and of storage period of bleached bovine tooth with three times in 37 degrees C water on the bond strength were studied using 10% citric acid-3% ferric chloride (10-3) or 10% citric acid (10-0) solution.


RESULTS
The bleaching of bovine tooth allowed for a dramatic decrease in the bond strength from 18.3 MPa to 9.8 MPa (1 time), and 3.9 MPa (3 times), even though the bovine enamel was etched by EG. However, when 10-3 or 10-0 solution was applied to the three times bleached enamel, bond strengths were 13.9 and 10.0 MPa, respectively. Furthermore, prolonging of the storage period of the three times bleached bovine tooth in water to 2 months resulted in a increase in the bond strength from 3.9 to 10.1 MPa, even if bovine enamel was etched by EG, and close to that obtained from the 10-3 etching.


CONCLUSIONS
To obtain the expected bond strength to bleached enamel, it is better to wait for 2 months for a restoration and use the 10-3 etching.
Wakami
Masanobu
M
Department of Crown Bridge Prosthodontics, Nihon University School of Dentistry at Matsudo. wakami.masanobu@nihon-u.ac.jp
Masuda
Mikiko
M
Kato
Hitomi
H
Tabei
Naoko
N
Watanabe
Tsukasa
T
Muramori
Juri
J
Saikawa
Takahiro
T
Aida
Masahiro
M
Nishiyama
Norihiro
N
D000818:Animals; D002417:Cattle; D002712:Chlorides; D019343:Citric Acid; D001840:Dental Bonding; D003738:Dental Cements; D003743:Dental Enamel; D045662:Dental Etching; D005290:Ferric Compounds; D033081:Shear Strength; D012996:Solutions; D014073:Tooth Bleaching
D002712:Chlorides; D003738:Dental Cements; D005290:Ferric Compounds; D012996:Solutions; D019343:Citric Acid; C024555:ferric chloride