Application of biologically-oriented dentin bonding principles to the use of endodontic irrigants.
OBJECTIVE
To compare the removal of smear layer and the structure of the hybrid layer formed after the use of EDTA or MTAD solutions when used as a final flush.


METHODS
Single-rooted extracted premolars (n=18) were collected and treated for root canal therapy using NaOCl irrigation followed by a final rinse of 17% EDTA, Biopure MTAD, or saline (negative control). The roots were obturated with gutta-percha and a hydrophilic HEMA-containing root canal sealer. The TEM specimens were impregnated with 50% silver nitrate to visualize sealing imperfections and nanoleakage. The structure of the coronal, middle and apical parts of root canal walls was examined using transmission electron microscopy.


RESULTS
After NaOCl irrigation, a final rinse with BioPure MTAD or 17% EDTA completely removed the 2 microm-thick smear layer on mechanically instrumented root canal walls. The BioPure MTAD hybrid layer was thicker than the 17% EDTA hybrid layer. Both the BioPure MTAD and EDTA caused a collapse of the dentin matrix structure which impeded sealer infiltration and the formation of high quality hybrid layer bonding. The hybrid layers created in smear layer-covered dentin exhibited less potential for nanoleakage than the MTAD or EDTA hybrid layers.
García-Godoy
Franklin
F
Biosciences Research Center, Department of Endodontics, College of Dental Medicine, Nova Southeastern University, Fort Lauderdale, FL, USA.
Loushine
Robert J
RJ
Itthagarun
Anut
A
Weller
R Norman
RN
Murray
Peter E
PE
Feilzer
Albert J
AJ
Pashley
David H
DH
Tay
Franklin R
FR
D001641:Bicuspid; D019343:Citric Acid / Q000009:adverse effects; D003094:Collagen / Q000187:drug effects*; D003188:Composite Resins; D003763:Dental Leakage / Q000209:etiology*; D003786:Dental Pulp Cavity; D003806:Dentin Permeability / Q000187:drug effects*; D017220:Dentin-Bonding Agents; D003890:Desiccation; D004318:Doxycycline / Q000009:adverse effects; D004492:Edetic Acid / Q000009:adverse effects; D005899:Glass Ionomer Cements; D006801:Humans; D046529:Microscopy, Electron, Transmission; D011136:Polysorbates / Q000009:adverse effects; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants / Q000009:adverse effects*; D012389:Root Canal Obturation / Q000379:methods; D018915:Root Canal Preparation / Q000379:methods*; D016369:Smear Layer
D003188:Composite Resins; D017220:Dentin-Bonding Agents; C481259:EndoRez; D005899:Glass Ionomer Cements; C475043:MTAD (intracanal irrigant); D011136:Polysorbates; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; C487957:Xeno III; C507316:fuji TRIAGE pink capsule; D019343:Citric Acid; D003094:Collagen; D004492:Edetic Acid; D004318:Doxycycline