Composite restoration

2. Class I amalgam restorations
 Amalgam is used for restoration of many carious and
fractured posterior teeth and in replacement of failed
restoration.
 If properly placed it provides many years of service.
 Understanding the physical properties of amalgam
and the principles of tooth preparation.

3.  Class I restorations restore defects on the occlusal
surfaces of posterior teeth, the occlusal thirds of the
facial and lingual surfaces of molars, and lingual
surface of maxillary anterior teeth.

4. Clinical Technique for Class I
Amalgam Restoration
 Initial Clinical Procedures :
 A preoperative assessment of the occlusal relationship
of the involved and adjacent teeth.
 Isolation of the operating field with the rubber dam
when removing deep caries (judged to be <1 mm from
the pulp),during amalgam condensation and for
mercury hygiene.

5. Initial Tooth Preparation
 It is defined as establishing the outline form by
extension of the external walls to sound tooth
structure , while maintaining a specified, limited
depth and providing resistance and retention forms.
 The outline form for the Class I should include only
the faulty, defective occlusal pits and fissures.
 Commonly the marginal outline for maxillary
premolar is butterfly shaped.

6. Sequence of Preparation
 Enter the deepest or most carious pit with a “punch
cut” using the No. 245carbide bur.
 As the bur enters the pit, an initial target depth of 1.5
mm should be established.
 Pulpal depth is 0.1 to 0.2mm into dentin. depth of
external walls should be 1.5 to 2 mm

7.  Incline bur distally to establish proper occlusal
divergence to distal wall.
 For premolars, the distance from the margin of
extension to the proximal surface usually should not
be less than ~1.6 mm,for molars the minimal distance
is ~2 mm.
 While maintaining the bur’s orientation and depth,
the preparation is extended distofacially or
distolingually.

8.  Maintain the bur orientation and depth and extend
along the central fissure towards the mesial pit.
 Ideally the width of the isthmus should be just wider
than the diameter of the bur ; minimal faciolingual
width and minimal occlusal convergence are desired.

9.  Remainder of any occlusal enamel defects is
included and the facial and lingual walls are
extended, if necessary.
 The preparation should have an outline form with
gently flowing curves and distinct cavosurface margin .
 For the initial tooth preparation, the pulpal walls
should remain at the initial ideal depth, even if
restorative material or soft caries remain, remaining
caries are removed in final tooth preparation.

10. Primary resistance form
1. Sufficient area of relatively flat pulpal floor in sound
tooth structure.
2. Minimal extension of external walls.
3. Strong, ideal enamel margins.
4. Sufficient depth (i.e., 1.5 mm) for adequate thickness
of the restoration.
Primary retention form:
 Slight occlusal convergence of two or more opposing,
external walls.

11. Final Tooth Preparation
 Removal of remaining defective enamel and soft
dentin on the pulpal floor.
 Pulp protection, where indicated.
 Procedures for finishing external walls.
 Final procedures of cleaning and inspecting the
preparation.

12.  Occlusal cavosurface bevel is contraindicated in the
tooth preparation for an amalgam restoration.
 It is important to provide an approximate 90- to 100-
degree cavosurface angle, which should result in 80- to
90-degree amalgam at the margin.
 Amalgam is a brittle material with low edge strength
and tend to chip under occlusal stress.

13. Extensive Class I Amalgam
Restoration
 lesion is considered extensive if the distance between
soft dentin and the pulp is judged to be less than 1
mm.
 Or when the faciolingual extent of the defect has
involved much of cuspal inclines.

14. Initial Tooth Preparation
 The outline, primary resistance and primary retention
forms are established through proper orientation of
the No. 245 bur and appropriate extension of the
preparation.
 Initial depth of 1.5-2mmshould be maintained.
 the preparation is extended laterally at the DEJ to
remove all enamel undermined by caries by
alternatively cutting and examining the lateral
extension of the caries.

15.  When the defect extends to more than one half the
distance between the primary groove and a cusp tip,
reducing the cuspal tooth structure and restoring it
with amalgam (“capping the cusp”) may be indicated
When the distance is two thirds, cusp reduction and
coverage is usually required because of the risk of cusp
fracture during subsequent functional occlusal
loading.

16. Final Tooth Preparation
 Removal of remaining infected dentin.
 If pulp exposure occurs the operator must decide
whether to apply a direct pulp cap or to treat
endodontically.
 Usually no secondary resistance or retention features
are necessary.

17. Tooth Preparation for Class I
Occluolingual Amalgam Restoration
 Occlusolingual amalgam restorations may be used on
maxillary molars when a lingual fissure connects with
the distal oblique fissure and distal pit on the occlusal
surface.
 Tooth preparaion includes the following:
1. the tooth preparation should be no wider than
necessary; ideally, the mesiodistal width of the
lingual extension should not exceed 1 mm except for
extension necessary to remove caries.

18. 2. When indicated, the tooth preparation should be
more at the expense of the oblique ridge, rather than
centering over the fissure .
3. Especially on smaller teeth, the occlusal portion may
have a slight distal tilt to conserve the dentin support of
the distal marginal ridge.
4. The margins should extend as little as possible onto
the oblique ridge, distolingual cusp and the marginal
ridge.

19. Clinical Technique for Class II
Amalgam Restoration.
 Class II restorations restore defects that affect one or
both of the proximal surfaces.
 Initial Clinical Procedures:
 Occlusal contacts should be marked with articulating
paper before tooth preparation.
 Isolation using rubber dam.
 Insertion of an interproximal wedge is useful to
depress and protect the rubber dam and underlying
soft tissue, separate teeth slightly.

20. Tooth Preparation for Class II Amalgam
Retoration That Involve Only One Proximal box
 Occlusal outline form:
 Enters the pit nearest the involved proximal surface
with a punch cut using a No. 245 bur.
 Viewed from the proximal and lingual aspects, the
long axis of the bur and the long axis of the tooth
crown should remain parallel during the cutting.

21.  Target depth of 0.1 to 0.2 mm into dentin. 1.5 mm as
measured from the central fissure and 2 mm from the
preparation external wall.
 While maintaining the same depth and orientation,
the bur is moved to extend the outline to include the
carious central fissure and opposite pit, if necessary.

22.  The isthmus width should be as narrow as possible,
preferably no wider than one quarter of the intercuspal
distance.
 Before extending into the involved proximal marginal
ridge the final locations of the facial and lingual walls
of the proximal box are estimated visually to prevent
overextension of the occlusal outline form(i.e.,
occlusal step) where it joins the proximal outline form
(i.e., proximal box).

23.  While maintaining the established pulpal depth and
with the bur parallel to the long axis of the tooth
crown, the preparation is extended mesially, stopping
approximately 0.8 mm short of cutting through the
marginal ridge into the contact area.

24. Proximal Outline Form
 The operator should visualize the desired final location of
the facial and lingual walls of the proximal box relative to
the contact area.
 The objectives for the extension of the proximal margins
are:
 include all caries lesion, defects, or existing restorative
material.
 Create approximately 90-degree cavosurface margins (i.e.,
butt-joint margins).
 Establish (ideally) not more than 0.5-mm clearance with
the adjacent proximal surface facially, lingually, and
gingivally.

25.  the initial procedure in preparing the outline form is
the isolation of the proximal enamel by the proximal
ditch cut.
 End of the bur is allowed to cut a ditch gingivally along
the exposed proximal DEJ, two thirds at the expense of
enamel and one third at the expense of dentin. the 0.8-
mm-diameter bur end cuts approximately 0.5 to 0.6
mm into enamel and 0.2 to 0.3 mm into dentin.
 the ditch is extended gingivally just beyond the caries
lesion or the proximal contact, whichever is greater

27.  When the extension places the gingival margin in
cementum, the initial pulpal depth of the axiogingival
line angle should be 0.7 to 0.8mm (the diameter of the
tip end of the No. 245 bur is 0.8 mm). the bur may
shave the side of the wedge that is protecting the
rubber dam and the underlying gingiva.

28.  Ideally the extension of facial and lingual margins of
the proximal box should be such that it provides
clearance of 0.2-0.3mm from adajcent tooth.
 Ideally the gingival margin should clear the adjacent
tooth by only 0.5 mm which measured with side of
explorer.
 Clearance greater than 0.5 mm is excessive, unless
indicated to include the caries lesion, undermined
enamel, or existing restorative material .

29. Preparation of Axial Wall
 It is an internal wall that is parallel to the long axis of
the tooth and it is always placed in dentin to obtain:
 Resistance and elasticity of dentin.
 Bulk of restoration.
 Placement of retentive lock.
 The axial wall should be straight or convex but never
concave.
 It should follow the contour of proximal surface.

30. Preparation of Gingival Seat
 It is an external cavity wall that is prependicular to the
long axis of the tooth.
 It is extended beyond the contact area or up to the
proximal lesion whichever is more.
 It is made flat so that the masticatory forces are
disturbed equally.
 The width of gingival seat :-
 0,6-0.8mm(premolars
 0.8-1mm(molars
 It consists of 23rd of dentin and 13rd of enamel.

31. Gingival Divergence of Facial and
Lingual Walls of Proximal Box
 The proximal ditch cut may diverge gingivally (i.e.,
converge occlusally) to ensure that the faciolingual
dimension at the gingival aspect is greater than at the
occlusal.
 The gingival divergence:
 Increase the retention form
 provides for the desirable extension of the facial and
lingual proximal margins to include defective tooth
structure or old restorative material at the gingival level.
 Conserve the marginal ridge and provide 90-degree
amalgam at the margins on this ridge.

32.  The proximal extensions are completed in two cuts,
one starting at the facial limit of the proximal ditch
and the other starting at the lingual limit, extending
toward and perpendicular to the proximal surface
(until the bur is nearly through enamel at the contact
level).
 Matrix band may be used around the adjacent tooth to
prevent damaging its proximal surface.

33.  He isolated enamel, if still in place, may be fractured
with a spoon excavator or by mesial movement with
the side of the nonrotating bur.
 To protect the gingiva and the rubber dam when
extending the gingival wall apically, a wooden wedge
should already be in place in the gingival embrasure to
depress soft tissue and the rubber Dam.

34.  With a sharp enamel hatchet cleaves away any
remaining undermined proximal enamel , establishing
the proper orientation of the mesiolingual and
mesiofacial walls.
 Proximal margins having cavosurface angles of 90
degree are indicated.

35. the Primary Resistance Form
(1) the pulpal and gingival walls being relatively level
(i.e., perpendicular to forces directed along the long axis
of the tooth).
(2) restricting the extension of the walls to allow strong
cusps and ridge to remain with sufficient dentin support.
(3) restricting the occlusal outline form to areas
receiving minimal occlusal contact.
(4) rounding of the internal line angles.
(5) providing enough thickness of the restorative
material.

36. Primary Retention Form
 Occlusal convergence of the facial and lingual walls.
 Dovetail design of the occlusal step, if present.

37. Final Tooth Preparation
 Removal of any remaining defective enamel and
infected carious dentin.
 Pulp protection
 Secondary resistance and retention forms:
 Using gmt to bevel or round axio pulpal line angle.
 Proximal Retention Grooves:
 Placed in the axiofacial and axiolingual line angles.
 Extend from gingival floor to the occlusal surface .
 Prepared with no.14 round bur with head diameter of
0.5mm.

39.  Proximal retentive locks:
 Placed on axiofacial and axiolingual line angles.
 Terminate at axiopulpal point angle.
 Circumferential slots:
 0.5-1mm deep inside dej.
 Prepared with inverted cone bur.
 Amalgam bonding agents.
 Amalgapins.

40. Procedures for finishing external
walls:
1- There should be no unsupported enamel and marginal
irrigularities present.
2- There should be a butt joint relation between the
tooth and amalgam.
3- Cavosurface bevel {20} at the gingival margin can be
given by gmt, to remove unsupported enamel rods.
 When the gingival margin is positioned gingival to cej
on root , the bevel is not indicated .

41.  Final procedures :cleaning, inspecting, desensitizing,
and bonding.

42. Clinical Technique for Class I Direct
Composite restoration
 Composite is presently the most popular tooth
colored material.
 The ada indicated the appropriateness of composite
for use as pit and fissure sealant, prr,and class I , II
restoration.
 The ada further stated ‘when used correctly the
expected life time of resin based composite can be
comparable to that of amalgam in class I , II, v .
 composite is a material that has sufficient strength for
class I , II.

44. Initial Clinical Procedure
 Clean the operating site with a slurry of pumice to
remove plaque biofilm and superficial stains.
 Shade Selection.
 Isolation of the Operating Site by rubber dam.
 Preoperative assessment of the occlusion.

45. Tooth Preparation
 The tooth preparation for direct posterior
composites involves:
(1) Creating access to the faulty structure.
(2) Removal of faulty structures.
(3) creating convenience form for the restoration.

46. Small to moderate Class I
 More flared cavosurface forms without uniform or flat
pulpal or axial walls.
 the initial pulpal depth is determined only by the
selective removal of carious tooth structure.
 Do not require typical resistance and retention form
features.

47. Large Class I
 The tooth is entered in the area most affected by the
caries lesion, with the elongated pear-shaped diamond
bur positioned parallel to the long axis of the tooth
crown.
 Pulpal floor initial depth 1.5mm ( 0.2 mm internal to
the carious DEJ).
 Mesial, distal, facial, and lingual extensions are
dictated by the caries lesion, old restorative material or
defect, cuspal and marginal ridge are preserved as
much as possible.

49.  Extensions into marginal ridges should result in at
least 1.5 mm of remaining tooth structure for
premolars and 2 mm for molars.
 Extending the outline form to sound tooth structure.
 No bevelling on occlusal margin.

50. Occlusal Cavosurface Bevelling
 Controversial effect of bevelling on the surface:
 Main goal- to maximize the exposure of end cut
enamel prisms.
 Normal preparation- result in end-cut enamel
prisms(orientation of enamel rods in cuspal inclines)

51. Clinical Technique for Class II Direct
Compoite Retoration
 Decision making:
 Expected presence of enamel periphery-ideal.
 Preparation is expected to extend onto the root
surface, potential problems with isolation of the
operating area- good technique is needed.
 Occlusal relationship- heavy occlusal contacts
problem.
 Preoperative wedging- separation of teeth, which may
be beneficial in reestablishing the proximal contact
with the composite.

53. Tooth Preparation
 Types of preparation:
 Conventional
 Modified design

54. Conventional Design
 For moderate to large decay.
 Include an occlusal step and a proximal box.
 Occlusal step:
 Similarly as for the Class I.
 The proposed facial and lingual proximal extensions
should be visualized.
 Initial occlusal extension toward the involved proximal
surface should go through the marginal ridge area at
initial pulpal floor depth, exposing the DEJ.
 Only faulty central groove is prepared.

55. Proximal Box
 Faciolingual width is dictated by extent of the defect.
 Not required to extend the proximal box beyond
contact with the adjacent tooth.
 The instrument is held parallel to the long axis of the
tooth crown.
 the facial and lingual margins have 90-degree margin.
 the gingival floor is prepared flat with an
approximately 90-degree cavosurface margin .

56.  The axial wall should be 0.2 mm inside the DEJ and
have a slight outward convexity.
 Finally excavation of remaining caries.
 Remove gingivally any un supported enamel.

57. Bevelling
 No occlusal bevel.
 Bevel of the proximal box:
 Conservative bevel 0.5-1mm.
 On the facial and lingual cavosurface margin.
 Provide more accessible location for finishing and
polishing.
 Gingival margin bevel requires clinical judgement:
 Near CEJ-thin enamel layer, bevel can remove the little
enamel layer.
 Presence of prismless enamel layer-less effective acid
etching.

58.  Bevelling is indicated:
 Gingival margin is above the CEJ.
 Adequate band of enamel remain

59. Box-only Tooth Preparation
 It is indicated when only the proximal surface is
defective, with no lesions on the occlusal surface.
 the instrument is extended through the marginal ridge
in a gingival direction.
 the axial depth is dictated by the extent of the caries
lesion.
 The facial, lingual, and gingival extensions are dictated
by the extension of the caries.
 No beveling or secondary retention is indicated.

61. Slot Preparation
 lesion is detected on the proximal surface, but the
access can be obtained from either a facial direction or
a lingual direction.
 A small round diamond is used.
 The instrument is oriented at the correct
occlusogingival position, and the entry is made as
close to the adjacent tooth as possible, preserving the
facial or lingual surface.

62.  the axial depth is determined by the extent of the
lesion.
 The occlusal, facial, and gingival cavosurface margins
are 90 degrees or greater.
 Care should be taken not to undermine the marginal
ridge during the preparation.