A study of the adhesion between dental cement and dentin using a nondestructive acoustic microscopy approach.
OBJECTIVE
The goal of the present study was to investigate the potential for acoustic microscopy techniques to characterize the cement-dentin interface in restored teeth.


METHODS
Special flat-parallel specimens and whole extracted teeth with restorations were scanned using a high-frequency (50 MHz) focused ultrasonic transducer. Visual acoustic images (B- and C-scans) of the cement-dentin interface were obtained nondestructively, analyzed and compared with optical images taken after the samples were cut along the scanning axis. The shear bonding strength of a subsection of specimens was tested in a Lloyd material testing machine.


RESULTS
An essential distinction between the acoustical properties associated with good and failed bonding has been shown. In the case of failed adhesion, the ultrasound signal reflection from the cement-dentin interface is up to four to seven times higher in magnitude than in the case of good bonding. The comparison of the ultrasound imaging data with the data obtained using an optical microscope revealed a strong correspondence with the acoustical and optical results with respect to the presence, position and dimensions of the defects. The specimens showing higher ultrasound reflection from cement/dentin interface have also shown lower shear bonding strength.


CONCLUSIONS
The results demonstrate that acoustic scanning with a high-frequency focused ultrasonic probe is a valuable method for nondestructive morpho-mechanical analysis of cement/dentin interface for either experimental models or whole restored teeth. An appropriately expanded approach can be widely used for the pre-clinical evaluation of dental materials. Further, this method may prove beneficial in the design of new diagnostic ultrasound devices and techniques for use within clinical dentistry.
Denisova
Liudmila A
LA
International Center for Advanced Material Characterization, Emanuel Institute for Bio-chemical Physics RAS, Moscow, Russia.
Maev
Roman Gr
RG
Leontjev
Valery K
VK
Denisov
Alexandre F
AF
Grayson
George G
GG
Rusanov
Fedor S
FS
Bakulin
Evgeny Yu
EY
Gavrilov
Dmitry Yu
DY
Grineva
Tatiana V
TV
D000268:Adhesiveness; D001840:Dental Bonding; D003799:Dental Stress Analysis; D003804:Dentin / Q000000981:diagnostic imaging*; D017220:Dentin-Bonding Agents; D005899:Glass Ionomer Cements; D006801:Humans; D008422:Materials Testing / Q000379:methods; D033401:Microscopy, Acoustic; D013718:Tensile Strength
D017220:Dentin-Bonding Agents; D005899:Glass Ionomer Cements