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Time used in acid etching of enamel for composite bonding

Operative Dentistry

Select an answer

A. 30-40 seconds
B. 60 seconds
D. Depends on the restorative material brand
C. 15- 20 seconds
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Correct Answer : C. 15- 20 seconds

Etching helps with enamel bonding: (35%?40% phosphoric acid) ? Opens, widens dentin tubules ? Demineralizes dentin (intertubular and peritubular dentinal tubules) ? Etches out mineral (hydroxyapatite ? 15-second etch is sufficient ? ? Recommend longer etching ?times for primary teeth, approximately 30 ?seconds. ? ? Removes smear layer ? Creates micro-tags for micromechanical retention ? Increases surface energy -> promotes wetting and adhesion ? Microleakage is virtually nonexistent at etched enamel margins.? If a frosty appearance isn?t achieved, repeat ?etching, Most common etchant used 37% phosphoric acid is applied for 15 seconds, rinsed for 15 seconds and dried for 15 seconds. Overdrying can cause postoperative sensitivity.


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