Cementum is the calcified avascular tissue that forms the outer covering of the root and attaches the teeth to the alveolar bone. There are two types of cementum - acellular/primary cementum which is the first formed and does not contain cells, covering the cervical third of the root. Cellular/secondary cementum forms after the tooth reaches occlusion, is more irregular and contains cells. Cementum develops through the excretion of cementoid by cementoblasts and the entrapment of some cementoblasts which become cementocytes. It joins enamel at the cementoenamel junction in various forms and dentin at the dentinocemental junction.

1. CEMENTUM
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2. CONTENTS
 INTRODUCTION
 DEVELOPMENT
 TYPES OF CEMENTUM
 STRUCURE AND COMPOSITION
 ACELLULAR AND CELLULAR CEMENTUM
 CEMENTOENAMEL JUNCTION
 DENTINOCEMENTAL JUCNTION
 PATHOLOGY
 ANKYLOSIS
 CEMENTUM RESORPTION
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3. CEMENTUM
 CEMENTUM is defined as
calcified avascular
mesenchymal tissue that
forms the outer covering of
root.
 The cementum is the part of
the periodontium that
attaches the teeth to the
alveolar bone.
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7. DEVELOPMENT OF CEMENTUM
 Cementoid is excreted by
cells called
cementoblasts within the
root of the tooth and is
thickest at the root apex.
 During the later steps
within the stage of
apposition, many of the
cementoblasts become
entrapped by the
cementum they produce,
becoming cementocytes.
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8. TYPES OF CEMENTUM:
1.ACELLULAR or PRIMARY
CEMENTUM.
2.CELLULAR or SECONDARY
CEMENTUM.
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10. ACELLULAR
CEMENTUM
 It is the first formed cementum.
 It does not contain cells and
covers approx. cervical third or
half of the root.
 Formed before the tooth reaches
the occlusal plane.
 Thickness: 30-230 micrometers
 Sharpey’s fibers make up most
of the structure of acellular
cementum and play a principle
role in supporting the tooth.
 It is formed after the tooth
reaches the occlusal
plane, is more irregular
and contain cells called
cementocytes in lacunae.
 Cellular cementum is less
calcified than acellular
cementum.
 Sharpey’s fibres occupy
a smaller portion and
may be less calcified.
CELLULAR
CEMENTUM
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14. CEMENTOENAMEL
JUNCTION
 The cementum joins the enamel to
form the cementoenamel junction
(CEJ), which is referred to as
the cervical line.
 Three possible types of transitional
interfaces may be present at the
CEJ.
 In about 60-65% of cases
cementum overlaps enamel, in
about 30% of cases edge to edge
butt joint exists and in about 5-10%
of cases cementum and enamel fail
to meet.
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16. Dentino-
cemental junction
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