Cavity classification & nomenclature:
-Describe different tooth numbering systems.
-Compile the nomenclature of tooth surface.
-Demonstrate the proper terminology and
nomenclature of the cavity; cavity wall, floors, line
angles, point angles and cavo-surface angles.
-Classify cavity preparations according to the Black's
A cavity is a defect in the hard tooth
structure resulting from dental
caries. This cavity is surgically
opened to expose the carious
Definition of Cavity
Mechanical alteration of a tooth to
receive a restorative material which
will return the tooth and area to
proper form, function, and esthetics
Preparation procedure includes all
defective and friable tooth structure
The carious material is removed and the cavity
is given a form that will assure
-proper retention for the restorative material.
-adequate resistance to fracture during
-immunity from recurrence of caries at the
margins of the restoration
-and protection for the vital pulp
Areas of Liability to Caries:
1. Pits and Fissures:
These are enamel defects or faults, which result from
incomplete union of enamel lobes during formation
of enamel. They are actual openings in which we
can force an explorer or a probe and upon
withdrawal, the explorer is met with resistance,
food debris stagnate in these areas with
subsequent fermentation and caries production.
A fissure results from the incomplete
union of two enamel lobes during the
formative period of enamel.
If complete union occurs between two
enamel lobes, the result will be a
groove. The explorer in this case will
pass smoothly because there is no
defect in the enamel.
A pit results from the incomplete union
of three enamel lobes during its
formation, if complete union happens,
the result will be a fossa.
2-Smooth surface caries:
a-Areas in the proximal surfaces of teeth
gingival to the contact area:
Areas between two adjoining teeth is a place
where food debris can stagnate and ferment
the acid produced will decalcify enamel,
where interproximal cavities occur.
B-Areas below the greatest diameter of the
tooth (buccal deflection ridge):
Areas on the lingual and buccal or labial
surfaces of teeth, below the area of greatest
diameter, provide a shelter for food debris,
where it collects, stagnates and ferments,
thus producing caries. These are also
smooth surfaces, as no pits or fissures are
Classification of Cavities:
1. Baume’s classification considering the
danger areas in teeth, cavities can be
-Pits and fissures cavities.
-Smooth surface cavities.
2. Black’s classification of
The classification devised by G.V, black, which
is based upon the site of onset of the
carious process, and the relative frequency
of the various sites involved, is most widely
adopted. He classified cavities into five
Black ‘s classification of carious lesions which
is still widely used in dental schools.
However, this classification is now regarded
as incomplete in that it does not include
root caries and secondary caries. Also, it
does not include non-carious lesions, which
are treated in the same way as carious
a) Class I Cavities:
Are those cavities originating in
anatomical pits and fissures. They are
found in the occlusal surface of molars
and premolars, the occlusal two-third
of the buccal and lingual surfaces of
molars and in the palatal surfaces of
b) Class II Cavities:
Are smooth surfaces lesions that occur in the
proximal surfaces i.e., mesial or distal of
molars and premolars.
c) Class III Cavities:
Cavities that occur in the proximal surfaces
(mesial and distal) of incisors and canines
(cuspids), but do not involve or include the
d) Class IV Cavities:
Cavities that originate on the mesial and distal
surfaces of incisor and canine teeth, but
caries is so extensive that the incisal angle
Both class III and IV are smooth surface
cavities, they differ only in the extent of
caries, in class IV the caries is progressive
and reaches the incisal angle while in
classIII caries is limited to the proximal
e) Class V Cavities:
Are smooth surface cavities occurring in
the gingival third of the buccal and
lingual surfaces of all teeth, excluding
cavities occurring in anatomical pits in
the palatal surfaces of upper incisors,
where they are grouped with class I
Class VI(Simon’s modification)
cavities on the incisal edge of the
anterior teeth or the occlusal cusp
heights of posterior teeth.
The walls,the line angle and the point
angles of these cavity preparations are
the same as those for the occlusal pit
and fissure cavities.
3- Sturdevant’s classification Cavities may be
classified according to the number of surfaces
affected by caries into:
a) Simple cavities:
Are cavities occurring in one surface only, e.g. simple occlusal,
simple buccal, simple mesial, etc.
b) Compound cavities:
Are cavities involving two surfaces, e.g. occluso-mesial or distal,
occluso-buccal or lingual, mesio- or disto-labial, mesio-palatal,
c) Complex cavities:
Are cavities involving more than two surfaces e.g. mesio-occlusodistal, occluso-bucco-lingual, mesio-labio-palatal, etc.
N.B.: Class I, II may be simple, compound or complex,
while class V is always simple and class IV never be simple.
Walls and Angle of
Black gave the following rules for naming the internal
parts of cavities
The walls take the names of the adjacent tooth
That wall of a prepared cavity, which is occlusal to the
pulp, and in a plane at right angles to the long axis
of the tooth, is called the pulpal wall or floor. In
case the pulp of the tooth is removed, and the
cavity thus extended to include the pulp chamber;
that wall is called the sub-pulpal wall.
The wall which is parallel to the long axis of the tooth
and approximates the pulp, is called the axial wall.
All the angles are formed by the junction of two walls
along a line, and are named by combining the
names of the walls joining to form the angle.
All point angles are formed by the junction of three
walls at a point, and are named by joining the
names of the walls forming the angle.
The Cavo-Surface Angle:
Is the angle formed by the junction of the wall
of the cavity with the surface of the tooth.
The cavo-surface angle of a cavity will be of
enamel, in cavities present in the root of
teeth, which are exposed due to gingival
recession, the cavo-surface angle will be
cementum. The enamel margin includes the
whole outline of the prepared cavity
The Dentino-Enamel Junction:
Also called amelo-dental junction, is the
line of junction of dentin and enamel
as it appears in the walls of the
The Enamel Wall:
Is that portion of a prepared cavity, which
consists of enamel, It includes the thickness of
the enamel from the dentino-enamel junction to
the cavo-surface angle.
The Dentin Wall:
Is that portion of the wall of a prepared cavity,
which consists of dentin.
The wall of the prepared cavity which is
occlusal to the pulp and in a horizontal
plane at right angle to the long axis of the
Any wall in the prepared cavity, which is
parallel to the long axis of the tooth.