5. Historical Background
1908-G. V Black father of operative dentistry
Established principles of cavity preparation
Dr. Arthur – developed instruments
Charles .E.Woodbury – Cavity design (class lll )
Dr. wedelsteadt --
1868* Dr. Jonathan Taft – bulky chisels
Bur drill (1/32 to !/5 inch )
Hand pieces (foot engine )
Hand pieces (air driven ultraspeed )
7. Cavity – Defect in enamel or in enamel and dentin
resulting from the pathological process of dental
careis
( Acc Charbeneau 3 Edition)
Cavity preparation
Mechanical alteration of a defective, injured or
diseased tooth in order to best receive the
restorative material which will reestablish a
healthy state for the tooth including esthetic
corrections where indicated, along with normal
form and function (Sturvdent 4 Edition)
Acc Gilmore
Acc Charbeneau
8. • Objectives of cavity preparation
Factors affecting tooth preparation
General factors
Diagnosis
Dental anatomy
Patient factors
Conservation of tooth structure
Restorative material factors
12. Classification of cavity
G.V .Black classification (Sturvdent 4 Edition)
According
Class l – pit and fissure restoration
-Restoration on occlusal surface of
premolar and molars
-Restoration on occlusal two thirds of
facial and lingual surfaces of molars
-Restoration on lingual surface of
maxillary incisors
13. Class ll –Restoration on proximal surfaces of
posterior teeth
Class lll - Restoration on proximal surfaces of
anterior teeth that do not involve the incisal angle
Class lV -Restoration on proximal surfaces of
anterior teeth that do involve the incisal angle
Class V – Restorations on the gingival third of the
facial or lingual surfaces of all teeth
Class Vl – Restoration on the incisal edge of
anterior teeth or the occlusal cusp heights of
posterior teeth
14. Modification of blacks original classification
Class Vl - cavities on both mesial and distal
proximal surfaces of bicuspids and molars when
restored will share a common occlusal isthmus
( Acc charbeneau )
(Markely and bronner )
Class ll – Cavities on single proximal surfaces of
bicuspids and molars
15. According to number of surfaces
involved
Simple
Compound
Complex
Simple
Compound
16. New cavity of classification
Site 1. Pits fissures and enamel on occlusal surface of
posterior teeth or other smooth surfaces such as Cingulum
pits on anterior
Site 2. Approximal enamel immediately below areas in
contact with adjacent teeth
Site 3. The cervical one third of the crown or,following
gingival recession, the exposed root.
Acc Graham J mount
(1997)
17. The four sizes of carious lesions
Size 1. Minimal involvement of dentine just
beyond treatment by remineralization alone.
Size 2. Moderate involvement of dentine. sound,.
That is, the remaining tooth structure is
sufficiently strong to support the restoration .
Size 3. The cavity is enlarged beyond
moderate.The remaining tooth structure is
weakened to the extent that cusps or incisal
edges are split,
Size 4. Extensive caries with bulk loss of tooth
structure has already occurred.
42. Class l, design 3
Indication ; in occlusal one to two thirds of facial
and lingual surfaces of molars and on lingual surfaces
anterior teeth of
General shape
46. Class l, design 5 : Indications
Occlusal surface, most of the facial or lingual surface
involved
Occlusal surface is not conducive to retention of
restoration
Location of margins
In occlusal cavity mesial
and distal margins located at
Corresponding axial angles
Gingival margins
–gingival third of the facial
or lingual Surface
Pulpal floor – internal boxes (mesial third)
48. Class l, design 6 :
Includes occlusal surfaces of molars or premolars
as well as portion of facial, proximal
or lingual surface in form of a table of an entire
cusp or section of cusp (marginal ridges )
Gingival margin should extend to allow
Occlusal clearance of 1.5-3 mm from
Opposing teeth
49. Class l, Design 7
Involves occlusal , facial and lingual surfaces of
molars and premolars
Pins and posts are indicated
50. Class l, design 8
Endodontically treated tooth
Pulp chamber is retention form
51.
52.
53. Out line form
• Extent of caries
• Extent for convenience
• Location of gingiva
• Convexity of proximal surface
• Location and extent of contact areas
Resistance form
Occlusal loading and its effects
63. Class ll, Design 1
Conventional design
Indications
Moderate to large size proximal
Lesion with occlusal surface cavity
promotes the cavity width of cavity to
exceed 1/4 0f intercuspal distance
66. Class ll, Design 2 (moderate design )
Indications
•Moderate to small sized proximal lesions
•In stress concentration area
•Width not exceeding 1/4 of intercuspal distance
General shape
width
68. Class ll, Design 3 (conservative design )
• Involves primarily proximal surface and very limited part
of occlusal Surface, not extending beyond adjacent
triangular fossa
•Sound occlusal crossing ridges
•Minimal loading areas
General shape
Internal anatomy
70. Class ll, Design 4 (Simple design )
•Proximal surface only
•Indications; Decay restricted to contacting or proximal
surface without undermining marginal ridges
Diastema or adjacent tooth is missing
72. Class ll, Design 5
Part of proximal surface ,with a limited access area on facial
or lingual surface
Indications :
•1)Preparation will have 4 surrounding walls
•small proximal lesions
•Marginal ridge intact
•Does not involve contact area
1)Do not have dovetail
2) Preparation will not
have surrounding walls
•medium proximal lesion
2) Have dovetail
73.
74. Class ll, Design 6
The occlusal ,proximal and part of the facial or lingual
surfaces
Indications ; Cusp is missing
Badly broken down teeth
76. Class ll, Design 7
(Combinations of class ll with class V )
Shape A : junctions between the class ll and class V via, the
Proximal , crossing the axial angles
Shape B : via buccal / lingual groove
Shape A Shape B
77. Class ll, Design 8
Two or more surfaces of an endodontically treated tooth
does not require post retention
78. Class lll
Amalgam is usually not indicated for anterior teeth due to
its esthetic , but distal surface of the cuspid is a unique
location
General principles are similar to class ll
cavity
preparation but with emphasis laid on in 5
areas of preparation
1 esthetic concern
2 extension for access
3 stress consideration enamel rod direction
Incisal access
79. Designs of cavity preparation at the distal slope of
the cuspid
Indications;
1 The lesion does not involve or undermine the distal
slope of cupid
2 bulky walls will remain, incisally, after removal of
Undermine tissues
3 the labials axial angle is intact
4 the restoration will be directly loaded by vertical
forces
80. Internal anatomy ;
Axial convex
Depth - .5
from DEJ
Retention
points :
Depth 1 to
2 mm in
dentin
81. Class lV
Indications :
•Incisal angle is undermined
•Labial and lingual walls intact
Labio lingual cross section
83. Class V cavity
Involvement :smooth surfaces apical to height of contour
on facial and lingual surfaces of all teeth eg ; erosion,
abrasion , hypoplasia, aplasia
Resistance and retention
To minimize the effects of displacing
forces forces grooves occlusal and
gingival walls are essential
- cementum completely removed
- Gingival margins follow the curvature of
the furcation
84. Class V design 1
•lesion are confined to
gingival third of the
facisal or lingual third
of the facial or lingual
surface
- axial angles intact
- no furcation
involvement
85.
86. Class V ,design 2
Lesions on facial or lingual gingival third have
involved axial angle
Lesion on facial or lingual gingival third are
apical to contact area
General shape
Mesiodistal cross section
88. Class V Design 3
Indications;
Lesion on gingival third facially or linguallly is continuous
with isolated decalcifications or lesions occlusal to height of
contour
Bilateral extension
89. Class V Design 4
Multiple lesions in gingival third with sound tooth
structure separating them
General shape
90. Class V Design 5
Internal
anatomy
Involves bifurcation or part of it
97. Recent concept of cavity designs
v/s old design
Black concept :
Extension for prevention :
Outline form – the cause of the problem
The logical alternatives :
Outdated class l cavity design ;
Dental update 1985 360-370
110. Conclusion
Although composite resins and crown and bridge
restorative dental techniques receive much attention,
amalgam will continue to be the most extensively used
restorative material for many years to come .
If it is used with care in minimal cavities, the restoration,
the tooth and the occlusion will all last longer!
111. References
Marzouk –operative dentistry
Sturdevant- opertive dentistry 4 th edition
Charbeneau – principles and practise of operative dentistry
Black’s operative dentistry
Conservative amalgam restoration jol .of prosth. Dent.
1973
New approaches to cavity design british dental journal
1984
Axial wall revisited j. of operative dent. 1990,42-48
Evaluation of cavity preparation dent update 1985, 357-380
Modern class ll cavity –new zealand dent j 1972,132-137
Coservative class ii cavities j of dental reasearch 1984, 306