Title page for ETD etd-06102009-063355
|Type of Document
||Hamandi, Rola Riad
||Effects of tooth quality, tooth structure, and cement mixing ratios on dental adhesion
||Master of Science
||Materials Science and Engineering
|Love, Brian J.
|Kander, Ronald G.
|Moon, Peter C.
|Wightman, James P.
|Date of Defense
Experiments were performed on a number of bovine dentin specimens with the
intent of understanding the effects of dentin quality and preparation on dentinal adhesion.
Dentin quality was evaluated by measuring its wetting characteristics and hardness
properties. The effects of chemical treatment, thermal dehydration and rehydration on
dentin quality were examined. The contribution of enamel to adhesion was evaluated by
comparing the adhesion of dentin samples that had the enamel ground off prior to bonding
with dentin samples that retained the enamel wall. Sulfuric acid and tannic acid etching of
dentin were performed for both ground and unground teeth. Unground dentin specimens
were also exposed to thermal aging at 65° C. The torsional bond strength of the dental
tissues under these modified processing conditions was evaluated using a commercial
glass-ionomer cement. The same procedure has been repeated on unground and ground
teeth by changing several different cement mixing ratio. The chemical, thermal, and
mechanical properties of the cement mixing ratios were evaluated separately to provide a
better understanding of adhesion. Acid etching treatment was found to improve dentin
wetting characteristics and roughened the dentin surface leading to improve dental
adhesion. Thermal treatment renders the dentin surface more hydrophobic and
subsequently reduces adhesion. Weaker strengths were measured for untreated and
ground teeth. This is related to lower mechanical interlocking and lower chemical
adhesion when the smear layer covers the dentin. Mixed failure modes were detected
during dentin debonding while cohesive failure within the cement were observed during
enamel debonding indicating that enamel bonded better to the cement than dentin did.
Improper cement mixing decreased the bond strength of enamel and dentin.
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