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TRANSCRIPT
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CEMENTUM
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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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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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Structure of tooth and its
parts
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Histological view of cementum
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DEVELOPMENT OF CEMENTUMCementoid 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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TYPES OF CEMENTUM:1.ACELLULAR or PRIMARY CEMENTUM.2.CELLULAR or SECONDARY CEMENTUM.
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Oral histology lab.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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Cellular cementu
m
Acellular cementum
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Oral histology lab.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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Dentino- cemental junction
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Thank you