Tooth Morphology (the study of the form of teeth)
MJ
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Tooth Morphology (the study of the form of teeth) Structure of teeth. Supporting structures. Deciduous tooth morphology. Secondary tooth morphology Teeth General arrangement of teeth is called the dentition Primary dentition Contains the
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01
Tooth Morphology (the study of the form of teeth) Structure of teeth.
Supporting structures.
Deciduous tooth morphology.
Secondary tooth morphology<br>
Supporting structures.
Deciduous tooth morphology.
Secondary tooth morphology<br>
02
Teeth General arrangement of teeth is called the dentition
Primary dentition
Contains the deciduous teeth
Secondary dentition
Contains the permanent teeth
Mixed dentition
Contains some deciduous and some permanent teeth<br>
Primary dentition
Contains the deciduous teeth
Secondary dentition
Contains the permanent teeth
Mixed dentition
Contains some deciduous and some permanent teeth<br>
03
Maxillary teeth Supported by the maxillary bone
Belong to the maxillary arch Figure courtesy Hu-Friedy<br>
Belong to the maxillary arch Figure courtesy Hu-Friedy<br>
04
Mandibular teeth Supported by the mandibular bone
Belong to the mandibular arch Figure courtesy Hu-Friedy<br>
Belong to the mandibular arch Figure courtesy Hu-Friedy<br>
05
Each arch is divided into a right and left quadrant Figure courtesy Hu-Friedy<br>
06
Types of teeth Incisors
Canines
Molars
Premolars Posterior teeth Anterior teeth<br>
Canines
Molars
Premolars Posterior teeth Anterior teeth<br>
07
Incisors Designed to bite or cut food
The biting surface is called the incisal edge.
Central incisor larger than lateral incisor.
Flattened crown with one root.
Upper central incisor is largest of all incisors. Figure courtesy Hu-Friedy<br>
The biting surface is called the incisal edge.
Central incisor larger than lateral incisor.
Flattened crown with one root.
Upper central incisor is largest of all incisors. Figure courtesy Hu-Friedy<br>
08
Canines Designed to cut and tear food
Upper canines larger than lowers.
Large conical crown with pointed incisal edge and one long root.
Upper canines have longest of all roots.<br>
Upper canines larger than lowers.
Large conical crown with pointed incisal edge and one long root.
Upper canines have longest of all roots.<br>
09
Premolars Used for tearing and chewing food
All have two cusps, equal size in uppers, smaller lingual cusp in lowers.
Upper first premolar has two roots (buccal and palatal), all others have one root.<br>
All have two cusps, equal size in uppers, smaller lingual cusp in lowers.
Upper first premolar has two roots (buccal and palatal), all others have one root.<br>
10
Molars All have large occlusal surface for grinding and chewing food.
All upper molars have three roots (palatal, mesiobuccal and distobuccal)
All lower molars have two roots (mesial and distal).
Upper first molar has five cusps, fifth one called ‘cusp of carabelli’.
Lower first molar has five cusps, three buccal and two lingual.
All other molars have four cusps.
Roots in third molars vary in number, uppers are often fused together. Figure courtesy Hu-Friedy<br>
All upper molars have three roots (palatal, mesiobuccal and distobuccal)
All lower molars have two roots (mesial and distal).
Upper first molar has five cusps, fifth one called ‘cusp of carabelli’.
Lower first molar has five cusps, three buccal and two lingual.
All other molars have four cusps.
Roots in third molars vary in number, uppers are often fused together. Figure courtesy Hu-Friedy<br>
11
Occlusion In a normal mouth all incisal edges and cusps of upper and lower teeth interlock to give a stable bite (occlusion).
The upper arch is usually wider so that the lower teeth bite into the middle of the upper teeth, or onto the cingulum of the incisors and canines.<br>
The upper arch is usually wider so that the lower teeth bite into the middle of the upper teeth, or onto the cingulum of the incisors and canines.<br>
12
Parts of the teeth Each tooth consists of a crown and root
The crown is covered by enamel
The root is covered by cementum
The crown and root are joined at the cementenamel junction
The cervical line separates the crown and root<br>
The crown is covered by enamel
The root is covered by cementum
The crown and root are joined at the cementenamel junction
The cervical line separates the crown and root<br>
13
Enamel Hardest tissue in the body
Covers the crown
Thickest over the tips of the crown
Thinnest where crown meets the root
Colour is determined by thickness Figure courtesy Hu-Friedy<br>
Covers the crown
Thickest over the tips of the crown
Thinnest where crown meets the root
Colour is determined by thickness Figure courtesy Hu-Friedy<br>
14
Enamel It is made up of 96% inorganic crystals arranged as prisms
Main mineral crystals are hydroxyapatite.
Junction where enamel meets dentine is called the amelodentinal junction.
Contains no nerves or blood vessels and therefore cannot experience sensitivity.
Non-living tissue which cannot grow or repair itself, but can remineralise after acid attack.
Can exchange minerals, especially fluoride, to form fluorapatite crystal which make the enamel surface harder still and more resistant to acid attack.<br>
Main mineral crystals are hydroxyapatite.
Junction where enamel meets dentine is called the amelodentinal junction.
Contains no nerves or blood vessels and therefore cannot experience sensitivity.
Non-living tissue which cannot grow or repair itself, but can remineralise after acid attack.
Can exchange minerals, especially fluoride, to form fluorapatite crystal which make the enamel surface harder still and more resistant to acid attack.<br>
15
Dentine Forms the bulk of the crown and root of the teeth
Covered by enamel in the crown
Covered by cementum in the root
Living tissue
Receives nutrition from dentinal tubules running from the pulp
Tubules are involved with toothache Figure courtesy Hu-Friedy<br>
Covered by enamel in the crown
Covered by cementum in the root
Living tissue
Receives nutrition from dentinal tubules running from the pulp
Tubules are involved with toothache Figure courtesy Hu-Friedy<br>
16
Dentine It is up to 80% inorganic.
It is composed of hollow tubules containing fibrils, which are sensory endings from the cells forming the dentine.
It is therefore a living tissue, and can transmit sensitivity.
It is formed by ondontoblast cells, which lie at the edge of the pulp chamber.
It can repair itself by producing secondary dentine.
Secondary dentine also forms as part of the natural ageing process.
Caries progresses rapidly through dentine because of its hollow nature.<br>
It is composed of hollow tubules containing fibrils, which are sensory endings from the cells forming the dentine.
It is therefore a living tissue, and can transmit sensitivity.
It is formed by ondontoblast cells, which lie at the edge of the pulp chamber.
It can repair itself by producing secondary dentine.
Secondary dentine also forms as part of the natural ageing process.
Caries progresses rapidly through dentine because of its hollow nature.<br>
17
Cementum The cementum is the layer covering dentine of the root.
It normally lies beneath the gingiva.
It allows attachment of the tooth to the supporting structure of the periodontal ligament.
Calcium Hydroxyapatite
Similar chemically to bone Figure courtesy Hu-Friedy<br>
It normally lies beneath the gingiva.
It allows attachment of the tooth to the supporting structure of the periodontal ligament.
Calcium Hydroxyapatite
Similar chemically to bone Figure courtesy Hu-Friedy<br>
18
Pulp Chamber Pulp is the soft tissue within the tooth structure.
Surrounded by dentine
Consists of connective tissue, blood vessels and nerves
Odontoblasts present on the wall of the pulp chamber Pulp Canals Figure courtesy Hu-Friedy<br>
Surrounded by dentine
Consists of connective tissue, blood vessels and nerves
Odontoblasts present on the wall of the pulp chamber Pulp Canals Figure courtesy Hu-Friedy<br>
19
Pulp It allows the tooth to feel hot, cold, touch, pain by stimulation of fibrils in dentine.
Vessels enter the tooth through the apical foramen, at the end of each root apex.
These tissues are enclosed within the pulp chamber of the tooth.
Chamber is lined by ondontoblast cells.
Gradual formation of secondary dentine with age causes pulp chamber to decrease in size and become narrower.<br>
Vessels enter the tooth through the apical foramen, at the end of each root apex.
These tissues are enclosed within the pulp chamber of the tooth.
Chamber is lined by ondontoblast cells.
Gradual formation of secondary dentine with age causes pulp chamber to decrease in size and become narrower.<br>
20
Periodontal tissues Support and attach the teeth to their bony sockets<br>
21
Diagram courtesy Oral-B Attachment tissues Alveolar bone Periodontal ligament Cementum<br>
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Periodontal Ligament This is a specialised fibrous tissue which attaches the teeth to the alveolar bone and surrounding tissues.
Fibres are made up of protein called collagen.
Acts as a shock absorber when tooth undergoes normal chewing movements, so that the tooth can bounce a little in its socket and not fracture.
Destruction of periodontal ligament occurs during periodontal disease.<br>
Fibres are made up of protein called collagen.
Acts as a shock absorber when tooth undergoes normal chewing movements, so that the tooth can bounce a little in its socket and not fracture.
Destruction of periodontal ligament occurs during periodontal disease.<br>
23
Alveolar bone The bony extensions of the maxilla and mandible, where the teeth are formed and from where they erupt into the mouth.
Special bone found only in the jaws.
Sole purpose is to support the teeth during their lifetime.
When teeth are extracted, alveolar bone gradually resorbs away.
Outer layer is hard compact bone, with the surface being called the lamina dura.
Inner layer is cancellous bone, sponge like in appearance to allow blood vessels and nerves to run through.
Destruction of the alveolar bone can occur during periodontal disease.<br>
Special bone found only in the jaws.
Sole purpose is to support the teeth during their lifetime.
When teeth are extracted, alveolar bone gradually resorbs away.
Outer layer is hard compact bone, with the surface being called the lamina dura.
Inner layer is cancellous bone, sponge like in appearance to allow blood vessels and nerves to run through.
Destruction of the alveolar bone can occur during periodontal disease.<br>
24
Cementum The cementum is the layer covering dentine of the root.
It normally lies beneath the gingivae.
It allows attachment of the tooth to the supporting structure of the periodontal ligament.<br>
It normally lies beneath the gingivae.
It allows attachment of the tooth to the supporting structure of the periodontal ligament.<br>
25
Gingivae This is the correct term for the gums.
In health they are light pink in colour with a stippled (orange peel) surface.
Form a 2mm crevice (gingival crevice) around the necks of each tooth, above periodontal ligament.
Gingivitis occurs when this area becomes inflamed.
Inflamed gingivae are red and shiny, with a swollen appearance.<br>
In health they are light pink in colour with a stippled (orange peel) surface.
Form a 2mm crevice (gingival crevice) around the necks of each tooth, above periodontal ligament.
Gingivitis occurs when this area becomes inflamed.
Inflamed gingivae are red and shiny, with a swollen appearance.<br>
26
EXERCISE<br>
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Eruption<br>
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Eruption Two sets of teeth develop in a person’s lifetime
The deciduous dentition contains 20 teeth
The permanent dentition contains 32 teeth
And for a period of time a child will have a mixed dentition
Containing some deciduous teeth and some permanent teeth<br>
The deciduous dentition contains 20 teeth
The permanent dentition contains 32 teeth
And for a period of time a child will have a mixed dentition
Containing some deciduous teeth and some permanent teeth<br>
29
Deciduous dentition The first teeth to appear are the deciduous incisor teeth at about 6 months
The last teeth to appear are the deciduous second molars at 2 ½ years<br>
The last teeth to appear are the deciduous second molars at 2 ½ years<br>
30
Deciduous dentition Figure courtesy Hu-Friedy<br>
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Deciduous dentition eruption ages<br>
32
Deciduous Teeth Deciduous teeth in general resemble their corresponding permanent teeth but there are some important differences.
Deciduous teeth are much smaller.
There is adequate space so crowding is uncommon.
Deciduous crowns are whiter.
Pulp chambers of deciduous teeth are relatively larger, their enamel is much thinner.<br>
Deciduous teeth are much smaller.
There is adequate space so crowding is uncommon.
Deciduous crowns are whiter.
Pulp chambers of deciduous teeth are relatively larger, their enamel is much thinner.<br>
33
Deciduous Teeth Deciduous incisors and canines are smaller versions of their permanent successors.
Deciduous molars have the same number of roots as permanent molars but differ in other respects.<br>
Deciduous molars have the same number of roots as permanent molars but differ in other respects.<br>
34
Deciduous Teeth The crowns of deciduous molars are more bulbous.
To provide space for the developing premolar, the roots of deciduous molars are more divergent than those of permanent molars.
Deciduous 2nd molars resemble miniature 1st permanent molars; but the shape of deciduous 1st molars is much less typical, having a pronounced mesio-buccal bulge.<br>
To provide space for the developing premolar, the roots of deciduous molars are more divergent than those of permanent molars.
Deciduous 2nd molars resemble miniature 1st permanent molars; but the shape of deciduous 1st molars is much less typical, having a pronounced mesio-buccal bulge.<br>
35
Permanent dentition The permanent teeth replace the deciduous teeth
The first permanent teeth to appear are the mandibular first molars
These teeth erupt behind the deciduous second molars
The next permanent teeth to erupt are the central and lateral incisors<br>
The first permanent teeth to appear are the mandibular first molars
These teeth erupt behind the deciduous second molars
The next permanent teeth to erupt are the central and lateral incisors<br>
36
Permanent dentition Figure courtesy Hu-Friedy<br>
37
Permanent dentition eruption ages<br>
38
Exercise<br>
39
What Is the Approximate Age of These Patients?<br>
40
CHARTING<br>
41
Tooth surfaces-posterior teeth Mesial – nearest the midline
Distal – furthest from the midline
Lingual - facing the tongue
Buccal – facing the cheek
Occlusal – chewing surface Figure courtesy Hu-Friedy<br>
Distal – furthest from the midline
Lingual - facing the tongue
Buccal – facing the cheek
Occlusal – chewing surface Figure courtesy Hu-Friedy<br>
42
Tooth surfaces-anterior teeth Labial – facing the lip
Mesial – nearest the midline
Distal – furthest from the midline
Lingual - facing the tongue
Incisal edge – biting surface of anterior teeth Figure courtesy Hu-Friedy<br>
Mesial – nearest the midline
Distal – furthest from the midline
Lingual - facing the tongue
Incisal edge – biting surface of anterior teeth Figure courtesy Hu-Friedy<br>
43
Tooth identification There is a convention for naming the teeth which must be followed<br>
44
The tooth is identified by The dentition – permanent or deciduous
The arch – maxillary or mandibular
The quadrant – right or left side of the mouth
The tooth type – incisor, canine, premolar or molar<br>
The arch – maxillary or mandibular
The quadrant – right or left side of the mouth
The tooth type – incisor, canine, premolar or molar<br>
45
EXERCISE<br>
46
Palmer notation Permanent teeth Figure courtesy Hu-Friedy<br>
47
Examples of palmer notation<br>
48
Palmer notation system Deciduous teeth Assigns a letter to the deciduous tooth depending on its position relative to the midline
Central incisors are closest to the midline and are given the letter A
The second molars are furthest and are given the letter E<br>
Central incisors are closest to the midline and are given the letter A
The second molars are furthest and are given the letter E<br>
49
Palmer notation Identification Deciduous tooth<br>
50
Palmer notation Deciduous teeth Figure courtesy Hu-Friedy<br>
51
Palmer notation Deciduous teeth<br>
52
EXERCISE<br>
53
FDI notation system – Permanent teeth Uses a two-digit number to identify each tooth
The first digit identifies the quadrant
The permanent quadrants are numbered from 1 through to 4
The second digit identifies the tooth
The permanent teeth are numbered from 1 through to 8<br>
The first digit identifies the quadrant
The permanent quadrants are numbered from 1 through to 4
The second digit identifies the tooth
The permanent teeth are numbered from 1 through to 8<br>
54
FDI- Identification Permanent tooth<br>
55
FDI notation system Permanent teeth Figure courtesy Hu-Friedy<br>
56
Examples of FDI notation<br>
57
FDI notation system Deciduous teeth Uses a two-digit number to identify each tooth
The first digit identifies the quadrant
The deciduous quadrants are numbered from
5 through to 8
The second digit identifies the tooth
The deciduous teeth are numbered from
1 through to 5<br>
The first digit identifies the quadrant
The deciduous quadrants are numbered from
5 through to 8
The second digit identifies the tooth
The deciduous teeth are numbered from
1 through to 5<br>
58
FDI Identification Deciduous tooth<br>
59
FDI notation system Deciduous teeth Figure courtesy Hu-Friedy<br>
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Examples of FDI notation<br>
61
EXCERCISE<br>