Post on 01-Jan-2016
CHEN ZhiCHEN Zhi
Wuhan University School of StomatologyWuhan University School of Stomatology
Operative Dentistry 3Operative Dentistry 3
Indication of Operative DentistryIndication of Operative Dentistry
Caries; Malformed, discolored,
or fractured teeth; Restoration replacement.
Tooth-colored restoration
For Class Ⅲ ,Ⅳ and Ⅴ ,— Esthetic Dentistry
For Class and Ⅰ Ⅱ ,
What are Tooth-colored materials?
What is their working mechanism?
What are the cavity preparation futures for tooth-colored restoration?
What are steps for tooth-colored restoration?
What are the advantage & disadvantageof tooth-colored restoration?
Tooth-Colored Materials
Composite resin
Glass ionomer cement
Compomer
Composite Resin
Traditional composites
Hybird composites
Flowable composites
Condensable composites Packable
Universal composites
Glass Ionomer
Chemical adhesion to dentin
Release Fluoride
Compomer
Compomer =
Composite + Ionomer
Dental Adhesionor
Dental Bonding
Adhesion is a process of solid and/orliquid interaction of one material withanother at a single interface.
Enamel bonding system
Enamel bongding depends on resin tagsbecoming interlocked with the surfaceirregularities created by etching.
Macrotags: form between enamel rod peripheries.
Microtags: smaller tags form across the end of each rod.
Macrotags and microtags are the basisfor micro-mechanical bonding.
Dentin bonding system
The difficulties of dentin bonding:
More water---wet bonding
Lower calcification
Richer organic---collagen network
Smear layer
The bond strength is primarily relatedto micro-mechanical bonding to theintertubular dentin which occures between tubules along the cut dentinsurface.
Dentin Bonding Agent, DBA
Early DBA were hydrophobic, bonded directly to the dentin smear layer. Bond strengths < 6MPa.
Later DBA removed the smear layer buttended to over-etch dentin.Bond strengths≈10~12MPa.
DBA were chemically modified to be more hydrophilic.Bond Strengths≈18~20MPa.
Careful dentin conditioning,Coupled with hydrophilic primer,Bond Strength≈22~35MPa.
The Development of DBAEnamel etch
(1955)
Dentine etch (1960)
Treatment of smear layer (1980)
Wet Bonding technique(1990)
First generation
Second generation
Third generation
Fourth generation: Total etch technique
Fifth generation: One bottle system
Sixth generation: All in one,2000
Seventh generation
Cavity Preparation
Three designs of cavity preparation:
1.Conventional
2.Beveled conventional
3.Modified
Beveled conventional cavity preparationsare similar to conventional preparation,in that the outline form has external,“box-like” walls, but with beveled enamel margin.
Beveled enamel margin
Beveled conventional cavity designs for Class , and preparationsⅢ Ⅳ Ⅴ
The advantages :
The ends of enamel rods are more etched
The increase in etched surface results ina stronger bond
Increase the retention and reduce marginalleakage and discoloration.
More esthtically
Modified cavity preparation
Have neither specified cavity wall structurenor specified pulpal depth, and have enamelmargins.
Conserve more tooth structure.
Modified cavity preparation
Initial Clinical Procedure
Local anesthesia
Preparation of the operating site
Shade selection
Isolation of the operating site with rubber dam or cotton rolls
Rubber dam
Clinical Procedure
Cavity preparation
Acid etching enamel & conditioning dentin
Matrix application
Application of bonding agent
Insertion of compositeFinishing procedures
Matrix application
Final proceduresFinal procedures
Cases
Conservative Operative Dentistry
Minimal intervention dentistry
is regards as a main stream in caries treatment in the 21st century.
Principles of Minimal Intervention dentistry
Remineralization of early lesions Reduction in cariogenic bacteria, to el
minate the risk of further demi-neralization and cavitation
Minimum surgical intervention of ca-vitated lesions
Repair rather than replacement of defective restorations
“The day is surely coming, and perhapswithin the lifetime of you young menbefore me, when we will be engaged inpracticing preventive, rather than reparative, dentistry. ”
— GV Black in 1896
University Minnisota School of Dentistry
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