Self-contamination of deep dentin by dentin fluid.
OBJECTIVE
To compare, with the use of a resin replica technique, surface features of deep, acid-conditioned dentin from vital human molars that were anesthetized with an anesthetic: Group 1: without a vasoconstrictor (Mepivacaine 3%), and Group 2: containing a vasoconstrictor (Lidocaine 2% with 1:80,000 epinephrine).


METHODS
10 Class I cavities with dentin caries were included in each group. Following complete caries removal, a total-etch technique was performed with 32% phosphoric acid (Uni-Etch) for 15 s. After rinsing, each cavity was air-dried for 1 s, then a slow setting vinyl polysiloxane (President) impression was taken. As a control, impressions were taken from three additional cavities in teeth that were anesthetized with Mepivacaine 3% but not acid etched. A TEM-grade epoxy resin was used to prepare replicas from the impressions. Polymerized replicas were coated with gold and examined with a scanning electron microscope.


RESULTS
In Group 1, fluid was visible leaving tubular orifices in all replicas. In addition, three were covered with a smooth, amorphous film that was different from the granular appearance of the smear layer in the control cavities. In Group 2, patent tubular orifices without fluid were observed in all specimens. Odontoblast process-like structures were seen from some dentin tubules.
Itthagarun
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Faculty of Dentistry, Prince Philip Dental Hospital, The University of Hong Kong, Hong Kong SAR, China. aitthaga@hkusua.hku.hk
Tay
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D000134:Acid Etching, Dental; D000328:Adult; D000779:Anesthetics, Local / Q000008:administration & dosage; D003731:Dental Caries / Q000473:pathology / Q000628:therapy; D003737:Dental Cavity Preparation / Q000145:classification; D003760:Dental Impression Materials; D003804:Dentin / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D019234:Dentinal Fluid / Q000187:drug effects / Q000378:metabolism*; D004837:Epinephrine / Q000008:administration & dosage; D004853:Epoxy Resins; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage; D008619:Mepivacaine / Q000008:administration & dosage; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D009804:Odontoblasts / Q000648:ultrastructure; D010756:Phosphoric Acids / Q000008:administration & dosage; D011145:Polyvinyls; D016628:Replica Techniques; D012833:Siloxanes; D016369:Smear Layer; D014662:Vasoconstrictor Agents / Q000008:administration & dosage
D000779:Anesthetics, Local; D003760:Dental Impression Materials; D004853:Epoxy Resins; D010756:Phosphoric Acids; D011145:Polyvinyls; D012833:Siloxanes; D014662:Vasoconstrictor Agents; C034183:vinyl polysiloxane; D008012:Lidocaine; D008619:Mepivacaine; D004837:Epinephrine