Pedodontics III Al Azhar University Palestine Gaza Upload By: Lama El Banna lama1997bana@gmail.com Faculty of oral and dental medicine

1. ‫الرحيم‬ ‫الرحمن‬ ‫هللا‬ ‫بسم‬

2. College of Dentistry
Pedodontic I
RESTORATION OF PRIMARY TEETH
Dr. Hazem El Ajrami

3. • Of all the many services the dentist provides
for his child patients, the restoration and
preservation of carious teeth is of major
importance, for if these teeth are lost
prematurely by caries, not only will the child
be handicapped for the present but significant
damage may be done which will impair the
normal functioning of his masticatory
apparatus for his entire life time. In this
respect, restorative dentistry is preventive as
well as corrective.

4. • Isolation:
The maintenance of a dry operating field
during cavity preparation and placement of the
restorative material is important. It helps
ensure efficient operating procedures and
development of a restoration that will be
serviceable. This could be accomplished by the
use of a rubber dam. It is generally agreed that
the use of the rubber dam offers the following
advantages:

5. 1. Save time:
The time spent in placing the rubber dam is
negligible and will invariably be made up and
additional time realized, through quick and
proper operative work, and elimination of the
rinsing, spitting, and talking routine of the
child patient.

6. 2. Aids management:
It has been found through experience that
many apprehensive or uncooperative children
can often be controlled more easily with a
rubber dam in place. Since the rubber dam
efficiently controls the tongue and the lip, the
dentist has greater freedom for carrying the
operative procedures to completion.

7. 3. Controls saliva:
This is an extremely important consideration
in the completion of an ideal cavity
preparation for primary teeth. The margin of
error is appreciably reduced when a cavity is
prepared in a primary tooth, which has a large
pulp and often extensive carious involvement:
Moreover minute pulp exposure may be easily
detected when the tooth is isolated. It is
equally important in cases of vital pulp
exposure to observe the true extent of the
exposure and the degree and type of
hemorrhage from the pulp tissue.

8. • The use of the rubber dam will prevent foreign
objects from coming in contact with oral
structures. When small pieces of filling
material, such as zinc phosphate cement, zinc
oxide and eugenol, and silver amalgam, are
dropped into the floor of the mouth or come in
contact with the tongue, they will stimulate
salivary flow and interfere with the operative or
restorative procedure.

9. 4. A rubber dam also prevents the possibility of
the small child, in a semireclining position on
the dental chair, swallowing or aspirating
foreign objects and materials.

10. • Basic principles in the preparation of cavities
in primary teeth:
In preparing cavities for restoring primary
teeth, although the basic principles of cavity
preparation are applied, there are certain
modifications in cavity design, which make
restorative care of these teeth unique. Most of
these modifications have to do with the
difference in morphology of the primary molars
from that of the permanent molars.

11. • Class I cavities in primary molars:
1. The outline form should include all pits,
fissures and grooves into which a sharp
explorer can penetrate.
2. A flat pulpal floor is generally advocated,
although some prefer to make the pulpal
floor slightly concave throughout to allow for
greater depth of the filling material, for better
distribution of stress in the restoration and to
avoid endangering the high pulpal horns.

12. 3. The depth of pulpal floor should be
established just beneath the dentinoenamel
junction (0.5 mm) to avoid pulp exposure.
4. All the internal line angles should be
rounded.
5. The side walls should slightly converge
towards occlusal so that the preparation will
follow the outer form of the crown.

13. 6. Beside the regular Class I cavity preparations
done in primary molars, occlusal spot
preparations have been recommended. In
such preparations only the carious pits or
groove is prepared and the tooth is restored
in the usual manner. These preparations are
applicable in any of the primary molars with
exception of the lower second primary
molars in which extension for prevention
including all deep pits and fissures is
recommended.

14. 7. From the clinical experience it has been found
that interproximal caries in primary molars
usually occurs in pairs. Proximal spot
preparations have been recommended for such
situations. If one of the primary molars has an
incipient proximal carious cavity while the
adjacent molars has proximal lesion, for example
a spot preparation in the mesial surface of second
primary molar and an occluso-distal cavity in the
neighboring first primary molar can be done. This
spot preparation should be small, not
undermining the marginal ridge and can be done
only in patients with low caries index.

15. • Class II cavities in primary molars:
1. These preparations include an occlusal, an
isthmus and proximal portion. The outline
form of the occlusal step should be dovetail-
shaped including all carious pits, fissures,
and developmental grooves.
2. The side walls of the occlusal step should
converge from the pulpal wall to the occlusal
surface.
3. The pulpal floor should be established just
beneath the dentinoenamel junction.

16. 4. Angles between the side walls and the pulpal
floor should be gently rounded.
5. Since a number of amalgam restorations fail
as a result of fracture in the area of the
isthmus, this area should be made as wide as
possible buccolingually without weakening
the cuspal areas or endangering the pulp. It
has been suggested that the optimum average
width of the isthmus should be approximately
one-half of the intercuspal dimension of the
tooth.

17. 6. The axio-pulpal line angle should be beveled
or grooved to reduce the concentration of
stresses and provide greater bulk of material
in the isthmus area, which is liable to fracture.

18. 7. The greater constriction of primary teeth
increases the danger of damaging the
interproximal soft tissues during cavity
preparation. The further the gingival wall is
carried down, the deeper pulpally must be the
axial wall to maintain the proper 1 mm width.
This clearly can endanger the pulp if the wall is
established too far gingivally.

19. • Therefore, The gingival seat of the proximal
box should be established just beneath the free
margin of the interproximal gingival tissue and
should be of sufficient depth to break contact
with the adjacent tooth (approximately l mm). It
is unnecessary to bevel the enamel of gingival
seat since the enamel rods at the cervix slope
occlusally.

20. 8. The proximal box line angles and walls should
converge towards the occlusal, following the
buccal and lingual surfaces of the tooth. This
provides for increased retention, carries the
preparation into selfcleansable areas, and
avoids undermining the adjacent cusps.
9. An axiobuccal and axiolingual retentive groove
may be included in the preparation. These
grooves will aid in the retention of restoration
and will reduce the flow of amalgam.

21. 10. If extensive proximal lesions are present,
excessive flaring of the proximal surfaces will
result in fragile unsupported tooth structure.
Therefore, removal of one or both of the cusps,
depending on the amount of carious
involvement, until the level of the pulpal floor,
and covering with a chrome steel crown it will
result in a more serviceable restoration.

22. 11. The mechanical retainers such as ivory should
not be used when condensing amalgam in Class
II cavities in primary molar, as they will not
produce a desirable finished restoration since
the primary molars have prominent
buccocervical ridge, marked constriction of the
crown in the cervical region, and sharply
converging buccal and lingual surfaces towards
the occlusal.
• A spot welded band or T-band matrix can be
successfully used producing a well contoured
restoration.

23. • Class III cavity preparation:
1. If the carious lesion has not advanced
appreciably into the dentin and if removal
of the caries will not involve or weaken the
incisal angle, a small conventional Class III
cavity may be prepared and the tooth
restored with composite. If the caries is
more extensive and the incisal angle is
intact, a dove tail preparation can be made,
the dove tail can be prepared on the lingual
or the labial surface of the tooth.

24. 2. The distal surface of the primary canine is a
frequent site of caries attack. The position of the
tooth in the arch, the characteristically broad
contact between the distal surface of the canine
and the mesial surface of the primary first molar,
and the height of the gingival tissue make it
essentially impossible to prepare a typical Class
III cavity and restore it adequately. So a
modified Class III preparation utilizing a
dovetail on the lingual or occasionally, on the
labial surface of the tooth can be done.

25. • Amalgam is generally the restorative material
of choice for this type of preparation. A spot-
welded or T-band matrix should be used. A
crescent shaped portion of the matrix material
is cut away from the lingual side for amalgam
condensation. Modern esthetic restorative
materials are now available. Cavity preparation
is more conservative and the fluoride content of
some of them provides advantages.

26. • Class IV cavity preparation:
1. In these cavities, caries involves the incisal
proximal angle of the anterior teeth.
2. If caries is not extensive, disking by sand
paper disc is performed to remove the decay,
and then fluoride is applied topically.
3. In regular Class IV cavity preparations,
composite resin material can be used for
restoration. However, when caries is
extensive, anterior chrome steel crown with
facing or acrylic jacket can be used.

27. • Class V cavity preparations:
Class V cavities are prepared like those in
permanent teeth, although the depth is not
carried more than 1.5 mm. One must make sure
in the cavity preparation that all decalcified areas
are included in the outline form. In all deep
preparations, a protective base should be used.
Since the enamel rods are directed incisally or
occlusally in primary teeth, it is not necessary to
bevel the gingival wall. Glass ionomer cement
could be used effectively for restoring these
cavities.

28. • Recent concepts in restorative dentistry:
The goals of restorative therapy are to restore
a tooth to a state of health, function, esthetics and
to prevent recurrence of caries. Until recently,
restorative dentistry was strictly based upon the
surgical model, which includes elimination of the
decayed hard tissue and subsequent restoration of
lost tooth structure. This was titled operative
dentistry. This concept which is "invasive" in
nature is now opposed by a medical "preventive"
model centered on preservation of tooth
structure.

29. • Preparation design:
The widely available preventive measures
and improved amalgam alloys as well as the
arrival of adhesive dentistry have drastically
decreased the size of cavity preparation.
Consequently, the principles of cavity design
for amalgam restorations as established by
G.V. Black at the end of the 19th century have
been gradually replaced by minimally invasive
preparations. Although some of Black's
principles still apply, less cavity preparation is
currently required. The material of choice for
this minimally invasive cavity design is an
adhesive restorative material.

30. • New caries classification:
 Based on the principles of adhesive dentistry,
Mount and Hume in 1997 advocated a new
classification for caries called the Sites Stages
(Si/Sta) concept.
 According to this classification, every carious
lesion is determined by two descriptors:
1. Three sites of susceptibility to caries, which are
actually the areas where bacterial plaque tends to
accumulate ( sites 1 to 3).
2. Five stage scale of caries progression (stage 0 to 4).

31. • Principles of Si/Sta:
1. Tooth structure saving:
 Preservation of sound caries susceptible
tooth structure.
 Preservation of marginal ridges by using slot
and tunnel preparations.
 Removal of loose and fragile enamel rods
only if directly exposed to occlusal load,
while other unsupported tooth structure may
be conserved and reinforced by the bonded
restoration.
 Preservation of demineralized dentin in the
deep portions near the pulp chamber to
protect the pulp tissue from direct operative
trauma.

32. 2. Utilization of modern adhesion technology
benefits:
 Mechanical benefits: strengthening of
tooth/restoration compound through micro
retention effect.
 Biological benefits: provision of proper
marginal seal at tooth restoration interface
which protects the pulp tissue and enhances
reparative power by preventing micro leakage.
3. Biointegration: which means biocompatibility,
function, esthetics and prevention of secondary
caries.

33. Thank You