Using extracted teeth for research: the effect of storage medium and sterilization on dentin bond strengths.
BACKGROUND
The Centers for Disease Control and Prevention has adopted guidelines for infection control of extracted teeth used for research and teaching, requiring that teeth be sterilized before use. The authors conducted a study to test the null hypothesis that the storage medium and sterilization method have no effect on composite-to-dentin bond strengths.


METHODS
The authors collected 170 bovine incisors, cleaned them and placed them randomly into one of six storage media at 37 degrees C for 60 days: distilled water (dH(2)O), 0.9 percent sodium chloride, 0.5 percent chloramine-T, 5.25 percent sodium hypochlorite (NaClO), 2 percent glutaraldehyde and 10 percent formalin. For sterilization, they autoclaved a subset of 10 specimens from every sample, while they stored another subset of 10 specimens from every sample (except for the 10 percent formalin sample) in 10 percent formalin for 14 days. The authors then embedded the specimens in epoxy and ground flat the facial surface to expose middle-depth dentin, which they polished to 600 grit. They used a dental adhesive to apply composite to the exposed dentin. The authors tested the composite-to-dentin shear bond strength 24 hours after bonding. They analyzed the data using global analysis of variance and, when appropriate, multiple post hoc tests (P = .05).


RESULTS
Storage in NaClO resulted in significantly lower bond strength than that of the other treatment specimens. Sterilization with the autoclave negatively affected the bond strength of specimens stored initially in dH(2)O or 10 percent formalin, while sterilization with formalin alone had no significant effect on bond strengths.


CONCLUSIONS
Storing bovine teeth in 5.25 percent NaClO may negatively affect composite-to-dentin bond strengths. Immersion in 10 percent formalin might be the best option for storage and sterilization of bovine teeth that are to be used in dental bonding studies in vitro.
School of Dentistry, University of North Carolina at Chapel Hill, NC 27599, USA.
Jason Jonghyuk
JJ
Lee
Anthony
A
Nettey-Marbell
Archie
A
Cook
Luiz A F
LA
Pimenta
Ralph
R
Leonard
André V
AV
Ritter
D000704:Analysis of Variance; D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate; D002417:Cattle; D002487:Centers for Disease Control and Prevention, U.S.; D003188:Composite Resins; D001840:Dental Bonding; D019551:Dental Disinfectants; D018865:Dental Research; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents; D005557:Formaldehyde; D017408:Guidelines as Topic; D008422:Materials Testing; D019279:Resin Cements; D012973:Sodium Hypochlorite; D013242:Sterilization / Q000379:methods*; D014021:Tissue Preservation / Q000379:methods*; D014081:Tooth Extraction; D014481:United States
D003188:Composite Resins; D019551:Dental Disinfectants; D017220:Dentin-Bonding Agents; D019279:Resin Cements; C511238:Single Bond Plus; D005557:Formaldehyde; D017438:Bisphenol A-Glycidyl Methacrylate; D012973:Sodium Hypochlorite