This document discusses contacts and contours in restorative dentistry. It defines key terms like proximal contact area and contours. Ideal contacts and contours provide benefits like preserving periodontal health and preventing issues like food impaction. The document discusses contact relationships and locations for different types of teeth. Factors like embrasures, marginal ridges and different theories of crown contour are also explained. Reproducing ideal contacts and contours is important for restoring form and function.

2. CONTACTS AND
CONTOURS
DR MEENAL ATHARKAR
MDS
DEPT OF CONSERVATIVE DENTISTRY AND ENDODONTICS

3. CONTENTS
• Introduction
• Definitions
• Benefits of ideal contact and contour
• Proximal contact area
• Types of teeth
• Proximal contacts of various teeth
• Methods of testing a contact area
• Problems associated with faulty reproduction of
contacts in a restoration

4. CONTENTS
• Embrasures
• Contact and embrasure relationship
• Marginal ridges
• Contours
• Traditional concepts of crown contour
• Types of contour and their management

5. CONTENTS
• Procedures for proper contacts and contours:
1)Intraoral procedures
2)Extraoral procedures
• Recent advances
• Conclusion
• References

6. INTRODUCTION
• A healthy dentition comprises of fully erupted
teeth with proper occlusal and proximal contacts
that help to stabilize and maintain the integrity of
the arch.
• A clinician’s role is to re-establish the original or
correct the faulty contact to form physiologically
stable contact and inabilty to restore this
relationship disrupts harmony and can result in
deleterious consequences like food impaction,
caries, drifting, tilting and rotation of teeth.

7. INTRODUCTION
• A thorough knowledge of the contacts and
contours of various teeth is mandatory for
understanding-
1. Predisposing factors of proximal caries like faulty
inter-relationships.
2. Significance of marginal ridges, embrasures for
re-establishing the form and function of
restored teeth.
3. Periodontal aspect and health of tooth to be
restored.

8. DEFINITIONS
• PROXIMAL CONTACT AREA:
• It denotes the area of proximal height of
contour of the mesial or distal surface of a
tooth that touches (contacts) its adjacent tooth
in the same arch
• CONTOURS:
• The facial and lingual surfaces possess some
degree of convexity that affords protection and
stimulation of the supporting tissues during
mastication.
(Sturdevant)

9. BENEFITS OF IDEAL CONTACT AND
CONTOUR
• Conserves the health of periodontium
• Prevents food impaction
• Makes area self cleansable
• Improves longevity of proximal restorations
• Maintains normal mesiodistal relationship of
the teeth in the dental arch

10. PROXIMAL CONTACT AREA
• Contact point and contact area:
• When teeth erupt to make proximal contact with
previously erupted teeth, there is initially a contact
point.
• The contact point becomes an area because of wear of
one proximal surface against another during
physiologic tooth movement.
• The physiologic significance of properly formed and
located proximal contacts cannot be overemphasized;
they promote normal healthy interdental papillae
filling of the interproximal spaces.

12. Dental anatomy:the form and
function of permanent teeth.

13. Importance of contact
• Preserves the stability and integrity of the arch by
maintaining normal mesiodistal relationship of
teeth.
• Prevent food impaction interdentally
• Protect the soft tissue from periodontal disease
• conserve the teeth from proximal caries
• Premature restorative failure does not occur if
stable proximal contact is present.

14. Size of contact
Anteriorly- contact point
Posteriorly –contact area about 1.5-2mm

15. Location Of Contact
• Anterior teeth – incisal one
third
• Posterior teeth - junction
of occlusal and middle one
third

16. • The proximal contact area is located in the
incisal third of the approximating surfaces of
the maxillary and mandibular central incisors.
• It is positioned slightly facial to the center of
the proximal surface faciolingually .
•

17. • Proceeding posteriorly from the incisor region
through all the remaining teeth, the contact
area is located near the junction of the incisal
(or occlusal) and middle thirds or in the
middle third.
• Because of these contacts being positioned
progressively lower cervically, larger incisal or
occlusal embrasures result posteriorly.

18. TYPES OF TEETH

19. 1)Tapering:
• Wide crowns
• Narrow cervical region
2)Square:
• Bulky
• Angular
• With little rounded contours
3)Ovoid:
• A transitional type between
tapering and square types
• Surfaces are convex but
infrequently they may be
concave

20. Tapering square ovoid

21. Methods of testing a contact
• Visual inspection
• Digital test
• Radiographic – paralleling technique

22. Contact Relationships Between Posterior Teeth
A. Point or marble-like contact areas present at time of eruption.
B. Broad flat contact areas resulting from excessive wear.
C. Typical contact areas resulting from the usual amount of wear
observed in a patient of middle age.
A B C

23. In general,
The smallest posterior contacts occur on the mesial
surfaces of the maxillary and mandibular first
bicuspids.
Then it become progressively larger from the first
bicuspids distally through the molars.

24. Problems associated with faulty
reproduction of contacts in a
restoration
1)Improper contact size
a)Too broad contact :
• It will change the tooth anatomy
• It will change the interdental ‘col’ by broadening
it. The delicate non keratinized epithelium may
get damaged increasing the chance of
periodontal tissue.
• With too broad contact the interdental area is
difficult to clean increase the risk of future decay.

25. b)Too Narrow contact :
• It will change the tooth anatomy
• The embrasure size will increase leading to
impaction of food vertically and horizontally,
thereby damaging periodontal tissue.

26. 2)Improper contact location
• If Contact are placed :
a) Too occlusally - It will cause flattening of
marginal ridges, resulting in too shallow
occlusal embrasure
b) Too buccally/lingually- will encroach upon the
respective embrasure
c) Too gingivally - will reduce the size of gingival
embrasure and encroach upon interdental
gingiva

27. 3)Open contact:
• Open contacts would create the problem,
ready inflow of food causing accumulation of
debris , plaque and damage to periodontium
leading to the periodontal disease

28. EMBRASURES
• Definition:
• Embrasures are V shaped spaces that originate at
the proximal contact areas between adjacent
teeth and are named for the direction towards
which they radiate. (Sturdevant)
• Cervical embrasure:
• When gingival recession occurs between the
teeth, the interdental papilla and bone no longer
fill the entire interproximal space. These voids
exist cervically to the contact areas and are called
cervical embrasures.

31. Tapering square ovoid

32. CONTACT AND EMBRASURE RELATIONSHIPS

33. Anterior :- Maxillary and Mandibular Teeth
 The lingual embrasures widen out more than the labial embrasures
due to the tapering cingulum portions of the anterior teeth.

34. Posterior: Maxillary Teeth
• A buccal view shows the contact areas of these to be located in the
occlusal thirds of the crowns.
• The occlusal embrasures are not as wide or as deep as the
embrasures between the first bicuspids and the cuspid teeth .
• The gingival embrasures are considerably larger in depth and width
than the occlusal embrasures and are quite uniform between these
teeth.

35. Posterior : Mandibular Teeth
• An occlusal view shows the contact areas to be centered near to the
midline of the crowns with only a slight tendency to be located
toward the buccal.
• The buccal and lingual embrasures between these teeth appear to
be progressively larger from the first molars to the third molars.
• It must be emphasized that the design of the contact areas and
embrasures between the teeth are influenced by the size and form
of the individual tooth crowns

36. Embrasures in anterior and posterior
teeth

37. Significance of embrasures
• The correct relationships of embrasures, cusps to sulci,
marginal ridges, and grooves of adjacent and opposing
teeth provide for the escape of food from the occlusal
surfaces during mastication.
• When an embrasure is decreased in size or absent,
additional stress is created in the teeth and the
supporting structures during mastication.
• Embrasures that are too large provide little protection
to the supporting structures as food is forced into the
interproximal space by an opposing cusp.
• A prime example is the failure to restore the distal cusp
of a mandibular first molar when placing a restoration.

38. • The lingual embrasures are usually larger than the
facial embrasures to allow more food to be displaced
lingually, because the tongue can return the food to
the occlusal surface easier than if the food is displaced
facially into the buccal vestibule.
• The marginal ridges of adjacent posterior teeth should
be at the same height to have proper contact and
embrasure forms.
• When this relationship is absent, there is an increase in
the problems associated with weak contacts and faulty
embrasure form.

39. EMBRASURES
• Serves two purposes:
• Provides a spillway for passage of food during
mastication.
• Prevents food from being forced into the
contact area.

40. MARGINAL RIDGES
• Rounded borders of enamel that forms mesial
and distal margins of occlusal surfaces of
molars and premolars and mesial and distal
margins of lingual surfaces of incisors and
canines.

41. A marginal ridge of proper dimensions help in :
Occlusal cuspal anatomy
 creating a adjacent Triangular fossa.
 Producing adjacent Occlusal embrasure

42. Importance of marginal ridge:
In restorative dentistry
• A marginal ridge should always be recorded in two planes bucco-
lingual and occluso-cervical.
• It should be compatible in height with the adjacent tooth.
• Should be compatible with the occlusal cusp anatomy, creating a
pronounced adjacent triangular fossa and producing an occlusal
embrasure.

43. Marginal ridge with normal occlusion
Clinical considerations in restorative dentistry — A narrative review

44. Faults in marginal ridge formation during restoration:
No marginal ridge
• This resulting in drifting of the adjacent tooth with normal marginal
ridge
• Slight tilting of the tooth with no marginal ridge
• Food impaction vertically between the teeth
Clinical considerations in restorative dentistry — A narrative review

45. Clinical considerations in restorative dentistry
— A narrative review

46. Clinical considerations in restorative dentistry
— A narrative review

47. Clinical considerations in restorative dentistry
— A narrative review

48. Clinical considerations in restorative dentistry
— A narrative review

49. Clinical considerations in restorative dentistry
— A narrative review

50. CONTOUR
• The facial and lingual surfaces possess some
degree of convexity that affords protection
and stimulation of the supporting tissues
during mastication. (Sturdevant)
• This convexity generally is located at the
cervical third of the crown on the facial
surfaces of all teeth and the lingual surfaces of
the incisors and canines.

52. • Functions of contour:
• Acts in deflecting food only to the extent that
passing food stimulates by gentle massaging
rather than irritates the investing tissues.
• Maintenance of periodontal tissues.
• Proximal height of contour helps to provide
contacts with proximal surfaces of the
adjacent teeth which prevents food
impaction.

53. • Provide adequate embrasure space gingivally
of the contacts for gingival tissues, supporting
tissues, blood vessels and nerves that serve
the supporting structures.
• For upper anterior teeth- essential
determinant for mandibular movement.
• Serves to decrease the tooth bulk from its
gingival third to incisal third.

54. TRADITIONAL CONCEPTS OF CROWN
CONTOUR
• Food deflecting theory
• Muscle action theory
• Plaque retention theory
• Anatomical theory
• Margin placement theory
Current controversies in axial contour design

55. • Food deflecting theory:
• A) According to Wheeler:
• He proposed that convexities should be created in the
cervical third of artificial crowns.
• These convexities were to deflect food away from free
gingiva.
• This "shunting" idea was based upon the premise that
• (1) food forcefully contacts free gingiva in mastication
and
• (2) this contact acts as an etiologic agent in gingival
disease.
• Wheeler went on to state that these contours, usually
called cervical ridges or cervical contours, have
considerable physiologic importance.

56. • Wheeler believed that properly designed
curvatures allow sufficient functional
stimulation for necessary tissue massage.
• He further stated that whether or not these
theories are true, these curvatures must be
physiologic because they are so consistent and
uniform.

57. • B) According to Morris:
• He noted that the position of the gingival margin is, in part,
determined by the buccal or lingual tooth surface
prominences, "being more apical with greater prominence
and more coronal with lesser prominence.“
• His emphasis on the importance of accessibility to oral
hygiene measures and self cleansing by muscle action and
saliva is significant.
• The importance of embrasure spaces was also emphasized
because encroachment of these spaces would decrease
accessibility.
• His concept was inspired by Hirschfeld's classic
observations of clinical and skull materials

58. • C) According to Hirschfeld:
• He noticed that a lingually malposed tooth
possessed a thicker and more coronal alveolar
buccal plate than the properly positioned
adjacent teeth.
• Conversely, the lingual plate was thinner and
more apically positioned than the adjacent teeth.
• Besides, the buccal (or lingual) alveolar crest was
flat if the contiguous tooth surface was flat, or it
curved coronally toward the proximal areas if the
tooth surface was convex mesiodistally.

59. • D)According to Herlands et al:
• They found that contours based on the food-
deflecting concept resulted in crowns that
were overcontoured, thus causing, rather than
preventing, gingival inflammation.
• Their efforts to prevent food impaction
produced contour thicknesses never seen in
nature.

60. • Herlands found that:
• 1. The impaction mechanism requires certain physical
conditions.
• The substance being impacted must be fairly firm in
consistency or else it will be mashed, and there must
be a propelling force directing it toward an easily
accessible cul-de-sac.
• Both forces and substance must exist within confining
resistant walls.
• More vigorous mastication and harder foods result in
heavily keratinized and clinically healthy gingivae

61. • 2. The maximum bulge in natural crown contours is no
more than 0.5 mm, and this is considered as inadequate
protection against an impaction mechanism.
• 3. Complete lack of contour is often observed when a tooth
prepared for full coverage is left uncovered for an extended
period of time, but the surrounding gingivae are usually
healthy.
• 4. The gingival sulcus itself is not an easily accessible cul-
de-sac. The free gingiva is held firmly against the crown by
the supra-alveolar system of connective tissue fibers.
• 5. An outward current of serum will flush foreign matter
from the gingival sulcus, the flow of which is increased by
heavier muscular action and harder food.
• 6. Embrasure contours are possibly even more important
than buccal or lingual contours.

62. • Muscle action theory:
• A) Herlands et al and Morris introduced the
"muscular-action concept" which used the
rationale of muscular molding and cleansing,
rather than food impaction, to explain the
observable clinical phenomena found around the
natural and artificial crowns.
• They considered this concept to be a more
accurate guide for the construction of gingivally
tolerated full crowns

63. • B) According to Perel:
• He studied the relationship between axial tooth
contour and marginal periodontium on dogs.
• Procedures producing undercontours and overcontours
on buccal and lingual crown surfaces were performed.
• Clinical and microscopic evaluations were made in
respect to the condition of the marginal periodontium
and the crevicular areas.
• He concluded that:
• 1. Undercontouring of axial surfaces did not produce
any significant changes in healthy gingivae.
• 2. Overcontouring of axial surfaces, on the other hand,
produced inflammatory and hyperplastic changes in
the marginal gingivae.

64. • Plaque retention theory:
• The proponents of this concept prefer axial
contours of artificial crowns which facilitate
oral hygiene measurements and promote self-
cleaning by muscle action of the tongue,
cheeks, and lips.
• Furthermore, they stated that crown contour
should not harbour any plaque traps

65. • Anatomic theory:
• Kraus, Burch and MiIIer introduced the anatomic or
biologic concept of tooth contour, a contour which
simulated natural, healthy teeth.
• They considered that a biologic contour was a self-
protective contour to the supporting tissues and
defended the gingival unit, attachment apparatus, and
protected bone from trauma and irritation.
• Improper contour often induced early breakdown of
the supporting structures and tooth tissue, resulting in
premature loss of teeth.
•

66. • They stated that facial and lingual convexities form the
height of contour of tooth crowns, which are located at
the gingival third of each tooth and are approximately
one-half millimeter wider than the adjoining
cementoenamel junction (CEJ).
• The exception to this general rule is on the lingual
surface of the lower molars and second premolars.
• There, the convexities measure approximately one
millimeter and are located halfway between the
occlusal plane and the gingival margin.

67. • Margin placement theory:
• Plays a significant role in gingival health.
• The majority of data indicate that subgingival
margins can be conducive to plaque
accumulation and to periodontal disease.
• A)According to Wagman:
• He began to observe the function of subgingival
contours pertinent to gingival health. He
emphasized the importance of establishing the
proper contour to maintain the "knife-like" shape
of the free gingival margin. This was to facilitate
the removal of microbial plaque.

68. • He believed that subgingival contour should be
made convex facially and lingually.
• This was to protect the gingival sulcus and to
promote a knife-like, free gingival margin.
• The degree of these convexities should not
exceed one-half of the thickness of the gingiva at
the height of its attachment.
• Proper interproximal contour was also suggested,
and undercontour was preferred to overcontour.

69. • B)According to Weisgold:
• He stated that subgingival contour should be dictated
by the level of the free gingival margin.
• When the gingival margin is placed coronal to the CEJ,
the subgingival contour should be made convex.
• On the other hand, when gingival margin is located
below the CEJ (on the root surface) due to recession,
the subgingival contour should be made flat.
• His clinical experiences have shown that the artificial
crown portion placed subgingivally should generally
imitate the original shape of the tooth.

70. Types of contour

71. • Improper location and degree of facial or
lingual convexities can result in serious
complications, where the proper facial
contour is disregarded in the placement of a
cervical restoration on a mandibular molar.
• Overcontouring is the worst offender, usually
resulting in flabby, red-colored, chronically
inflamed gingiva and increased plaque
retention.

72. FACIAL AND LINGUAL CONTOURS
• Facial and lingual convexities
• Facial and lingual concavities

73. Facial and lingual convexities
• It has been revealed that there is always more inherent danger in
overconvex rather than under convex facial and lingual contour.
• The overconvex can create an undisturbed environment for the
accumulation and growth of cariogenic plaque at gingival margin

74. Facial and lingual concavities
• Deficient or mislocated concavities will lead to premature contacts
during mandibular movement
• Excessive concavities can invite extrusion,rotation,or tilting of
occluding cuspal elements into non-physiologic relations with
opposing teeth.

75. Guidelines To Contouring Crowns:
Buccal and lingual contours- flat, not fat. plaque retention- infrabulge
of the tooth. Reduction or elimination of the infrabulge would
reduce plaque retention
Open embrasures- If plaque is a primary etiologic factor in
gingivitis,then every effort should be made to allow easy access to
the interproximal area for plaque control.Open embrasure spaces
will allow for this easy access .
Location of contact areas -Contacts should be high (directed
incisally) and buccal in relation to the central fossa (except
between maxillary first and second molars)

76. Proximal contour according to
different types of teeth
• Tapering teeth:
• Starting at CEJ, surface presents
concavity to contact areas , and
convex from there to crest of
marginal ridges.
• Concavities are pronounced on
mesial surface.

77. • Square teeth:
• Mesial surfaces are Plane instead of curved.
• Distal surfaces are flat or slightly convex.

78. • Ovoid teeth:
• Convex from incisal angle to cervix.
• Premolar : bell shaped.
• Molars : mesial surface is convex.

79. Management of faulty contours of
restorations
• 1. Overcontoured proximal contour:
• Recontour if possible.
• Files- rhein trimmer
• WEDELSTAEDT chisel or bard parker no. 12
blade.
• Rotary instruments- sand disk, flame shaped
finishing burs

81. • 2. Subgingival contours:
• Low speed reciprocating action hand piece
system
• EVA system using wedge shaped files.

82. • 3. Undercontoured proximal contour:
• Replace the restoration

83. PROCEDURES FOR PROPER CONTACTS
AND CONTOURS
• Intraoral procedures:
1. Tooth movement
2. Matricing
• Extraoral procedures:
1. Wax pattern
2. Cast adjustments

84. • 1) Tooth movement:
• Tooth movement or separation of teeth is
defined as the process of separating the
involved teeth slightly away from each other
or bringing them closer to each other, and/ or
changing their spatial position in one or more
dimensions.

85. • Objectives:
• To bring drifted, tilted or rotated teeth to their
indicated physiological positions.
• To close space between teeth.
• To move teeth to another location.
• To move the teeth occlusally or apically to
make them restorable.

86. • To move teeth to a position so that when
restored, they will be in a most esthetically
pleasing situation.
• To move teeth in a direction and to a location
to increase dimensions of available structure
for resistance and retention form.
• To create sufficient space for thickness of
matrix band.

87. • Methods of tooth separation:
• 1. rapid or immediate separation
• 2. slow or delayed separation

88. • 1. rapid or immediate separation:
• Tooth movement is achieved rapidly over a
short period of time.
• May be achieved by wedge principle or
traction principle.
• Mechanical type

89. • Indications:
• As preparatory to slow movement
• To maintain space gained by slow movement.
• Separation shouldn’t exceed 0.2-0.5 mm.

90. • 1. separation by wedge principle:
• In this principle, a pointed, wedge shaped
device is inserted between the contacting
teeth to produce the desired amount of
separation.
• eg. Elliot’s separator, wedges

91. • A) Elliot’s separator:
• Mechanical device.
• It has a single bow with two jaws which can be
adjusted by a knob.
• The jaws are positioned in the interdental area
between the two contacting teeth gingival to the
contact area, without causing damage to the
interdental papilla.
• When the knob is turned clockwise, the jaws
move towards one another thereby wedging the
teeth apart.

93. • 2. separation by traction principle:
• This employs a mechanical device to engage
the proximal surfaces of the contacting teeth
and bodily moves them apart to bring about
the separation.
• Eg. Ferrier double bow separator.
• non interfering true separator.

94. • A) Ferrier double bow separator:
• Mechanical device has 2 bows.

95. • The advantage of this device is that the
separation is shared by both the contacting
teeth and is stabilized throughout the
operation.
• This device is employed during cavity
preparation and finishing of class III direct gold
restoration.

96. Ferrior double bow separator

97. B) Non interfering true separator

99. • 2. slow or delayed separation:
• Indications:
• When teeth have tilted, drifted or rotated to a
considerable extent and rapid separation is
not useful.

100. • Slow separation is achieved by:
• 1. rubber dam sheet
• 2. separating rubber band
• 3.Separating ligature wires
• 4.oversized resin temporary crowns
• 5.orthodontic appliances

101. • 1. rubber dam sheets:
• Separation occurs due to the thickness of the
sheet.
• The time taken- 1to 24 hours or more
• In case pain develops dental floss may be used
to remove the rubber dam material.

102. • 2. separating rubber band:
• A separating rubber band used for
orthodontic purposes can be used for
achieving slow separation.
• It can be stretched and positioned
interproximally between the teeth to produce
slow separation.

103. • separating rubber rings or bands:

104. • 3. separating ligature wires:
• Orthodontic brass ligature wire can be passed
through the embrasure triangle beneath the
contact area to form a loop around the
contact area.
• The two ends can be twisted together to
create separation not beyond 0.5 mm.
• The wire can be tightened periodically to
increase the separation.

106. • 4. Oversized resin temporary crowns:
• Temporary crowns are made oversized in the
mesiodistal dimensions and periodically resin
is added to the contact areas to increase the
amount of separation.

107. • 5. orthodontic appliances:
• Fixed orthodontic appliances are the most
effective and predictable means of achieving
slow tooth movement.
• They may be used when extensive
repositioning of teeth is needed.

108. • Extraoral procedures:
• 1. wax patterns
• 2. Cast adjustments

109. Recent advances
• 1. contact forming instruments:
• create good contacts with posterior
composites.
• They push matrix towards contact area during
light curing.
• Eg contact pro, optra contact

111. 2. XTS Freedman Contact Forming Composite
Instrument:
• provide improved contact forming for large
Class II Restorations.

112. • 3. contact rings:
• Work by providing slight separation of
contacting teeth.
• 2 generations:
• 1st- (1990s)- palodent bitine
- contact matrix
- composi tight

113. • 2nd- composi tight 3D soft face ring system
- V3 ring system

114. 4.Kesling and dumbell separators

115. CONCLUSION
• From cariogenic aspect, there may be only 20
occlusal surfaces.
• There are 60 contacting proximal and 64 facial
and lingual surfaces.
• Proper restoration of anatomical landmarks is
important for enhancing the longevity of
restorations as well as to maintain the occlusal
health and harmony

116. CONCLUSION
• Improper contacts can result in food impaction
between the teeth, producing periodontal
disease, carious lesions, and possible movement
of the teeth.
• In addition, retention of food is objectionable by
its physical presence and by the halitosis that
results from food decomposition.
• Proximal contacts and interdigitation of the teeth
through occlusal contacts stabilizes and maintains
the integrity of the dental arches.

117. REFERENCES
• Textbook of operative dentistry- VIMAL SIKRI.
1st edition.
• Dental Anatomy, Physiology, Occlusion-
WHEELER’s 5th edition.
• Operative dentistry- Modern theory and
practice- M. A. MARZOUK 1st edition.
• Art and Science of Operative dentistry-
STURDEVANT 4th edition.

118. • Traditional concepts of crown contour-
• 1)Current controversies in axial contour design.
(Anthony H. L. Tjan, Dr. Dent., Harvey Freed, and Gary
O. Miller)
• 2)Desigining crown contour in fixed prosthodontics: A
neglected arena.(Yashpal Singh 1 Reader, Dept. of
Prosthodontics 2 Monika Saini )
• Marginal ridge-
• Clinical considerations in restorative dentistry — A
narrative review (Ashwini Tumkur Shivakumar, Sowmya
Halasabalu Kalgeri, Sangeeta Dhir)