Download sudi--introduction of DA

ORAL ANATOMY
&
ORAL HISTOLOGY
• Diphyodont
• Polyphyodont
• Hetero dont
• Homodont
MAN
 Diphyodont - Heterodont
• “Deciduous”  Latin means “FALL OFF”
• “Milk teeth” – “Temporary teeth” – “Baby
tooth”
• 6 months – 2 years
• Mixed dentition period  6 – 12 years
• Permanent teeth – 6 yrs to 21yrs
• Maxillary – upper jaw
• Mandibular – lower jaw
Functions of teeth
• Mastication (Chewing)
• Phonation (Speech)
• Esthetics (Appearance)
• Self protection
Parts of a Tooth
– Crown
– Root
R
O
O
T
Cervix / neck
CROWN
MOLAR TOOTH
CROWN
R
O
O
T
R
O
O
T
Anatomical Crown – covered by enamel
Clinical Crown – visible in the oral cavity
Anatomical Root – covered by Cementum
Clinical Root – Covered by gingiva
Types of Teeth:
Incisors: Have a sharp thin edge  cutting.
Canines:  cutting and tearing.
Premolars: have two cusps  tearing and crushing.
Molars: Have 4 to 5 cusps and a broad surface 
grinding and chewing
Structure of Tooth
and
Supporting Structures
Enamel
• Outermost covering
• Hardest
• Yellowish - grayish white
• Non-living tissue
Dentin
• Hard – connective tissue
• Bulk of the tooth
• Covered by Enamel – Crown
Cementum - Root
Cementum
- Covers Root
- Yellowish
- Anchorage
Pulp
• Soft connective tissue
• Central portion
• Nerves and blood vessels
• Cells, fibers, intercellular substance
Supporting structures
of teeth
• Alveolar sockets
• Periodontal ligament (collagen fibers)
Junctions
• Cemento – Enamel Junction
• Dentino – Enamel Junction
• Cemento – Dentinal Junction
Types of Dentition
1. Deciduous Teeth
2. Permanent Teeth
Deciduous teeth
• Primary teeth
• Baby teeth
• Milk teeth
• Lacteal dentition
Dental formula
2
1
2
1
2
2
Permanent teeth
• Secondary dentition
1. Successor / Succedaneous teeth
2. Non-successor / Non-succedaneous teeth
Formulae for teeth
• I – Incisor , C – Canine , P – Premolar , M – Molar
2
I
1
C
2
P
3
M
Dental formula
2
1
2
3
2
1
2
3
• Dental formula for Deciduous teeth
• I 2 / 2 C 1/ 1 M 2 / 2 =
10  2 x 10 = 20
• Dental formula for Permanent teeth
• I 2/2 , C 1/1 , P 2/2 , M 3/3 = 16  2 x 16 = 32
Position of teeth
Anterior
Teeth
Posterior
Teeth
Facial Surface
1.Labial
2.Buccal
Lingual / Palatal
1.Palatal
2.Lingual
Incisal / Occlusal
1.Incisal
2.Occlusal
Proximal surface
1. Mesial
2. Distal
Tooth numbering system
• Recording data
• Communication
• 1. Zsigmondy / Palmer notation
• 2. Universal system
• 3. FDI ( Federation Dentaire Internationale)
Zsigmondy - Palmer notation / Grid system
• Adolph Zsigmondy in 1861
• Arches are divided  quadrants
• Deciduous teeth
Right
ED CBA ABCDE
E D C BA AB C D E
Left
Permanent teeth
• Central incisor numbered 1 through 8 in each arch
Right
left
87654321
12345678
87654321
12345678
• Advantages
– Many countries use this system
– Simple
• Disadvantage
– More Chances of error in noting sides
Universal system – Deciduous teeth
• Parriedt 1882
• Deciduous teeth
• Maxillary teeth beginning with right second molar
use the letter A through J , for mandibular teeth K
through T
Right
Left side
ABCDE
F G H I J
TSRQP
O NMLK
Universal system – Permanent teeth
• Right III Maxillary teeth numbered as 1 through 16
• Mandibular left III molar 17 through 32
Right
1 2 3 4 5 6 7 8
Left
9 10 11 12 13 14 15 16
32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17
• Disadvantage
– Needs more practice for quick & correct notation
FDI system
• Two digit / ISO 3950 notation
• adopted by WHO
FDI system – Permanent teeth
• Permanent dentition – 1 to 4
Upper right
Upper left
18 17 16 15 14 13 12 11 21 22 23 24 25 26 27 28
48 47 46 45 44 43 42 41 31 32 33 34 35 36 37 38
FDI system – Primary teeth
•
•
•
•
5 - maxillary right
6 - maxillary left
7 - mandibular left
8 - mandibular left
Left
Right
55 54 53 52 51
61 62 63 64 65
85 84 83 82 81 71 72 73 74 75
• Advantages
– Accepted by WHO
– Less chances of error
– Easy to follow
Trait Categories
• Set trait
– Deciduous teeth
– Permanent teeth
• Arch trait
– Maxillary
– Mandibular
• Class traits
– Incisors
– Canines
– Premolars
– Molars
• Type trait
• Incisors – Central / Lateral
• Premolars – 1st / 2nd Premolar
• Molars – 1st / 2nd / 3rd Molar
Descriptive Division of the Tooth
Division of Crown into thirds
– Facial / Lingual surface
• Cervical third
• Middle third
• Incisal / Occlusal third
– Facial / Lingual surface
• Mesial third
• Middle third
• Distal third
– Mesial / Distal surface
• Labial third
• Middle third
• Lingual third
– Mesial / Distal surface
• Cervical third
• Middle third
• Incisal / Occlusal third
Division of root into thirds
• Labial / Lingual & Mesial / Distal surfaces
– Cervical third
– Middle third
– Apical third
– Mesial / Distal surface
• Facial third
• Middle third
• Lingual third
– Facial / Lingual surface
• Mesial third
• Middle third
• Distal third
Line angles
• Junction between two surfaces that meet
each other
• Posterior teeth – 8
line angles
– Mesio buccal
– Disto buccal
– Mesio lingual
– Disto lingual
– Mesio occlusal
– Disto occlusal
– Bucco occlusal
– Linguo occlusal
• Anterior teeth – 6
line angles
– Mesio labial
– Disto labial
– Mesio lingual
– Disto lingual
– Labio incisal
– Linguo incisal
Point angles
• Point where three surfaces meet and are
named by joining the name of those three
surfaces which meet.
• Both anterior and posterior  4 point angles
– Mesio-bucco-occlusal
– Mesio-linguo-occlusal
– Disto-bucco-occlusal
– Disto-linguo-occlusal
Descriptive terms
• Cusp: It’s a point, peak, rounded elevation
on the crown portion of a tooth making up
a divisional part of the occlusal surface.
• Occlusal surfaces
• Each cusp – representative of a center of
calcification (a lobe)
• Each cusp  2 cusp slopes  Mesial cusp
slope and Distal cusp slope
– Canines  1 cusp
– Premolars  2 cusps
– Molars  4 / 5 cusps
Tubercle
• It is a smaller elevation on some portion of
the crown produced by an extra formation
of enamel
– Tubercle of Carabelli
Cingulum
• Bulge or Elevation on the lingual surface
of incisors or canines
Ridge
• Linear elevation present on the surface of the
tooth
• Depending on location
– Labial ridge
– Lingual ridge
– Buccal ridge
– Incisal ridge
– Marginal ridge
– Cuspal ridge
1. Marginal ridge
• Rounded borders of enamel that form margins
of anterior / posterior teeth
• Anterior teeth  boundary of lingual surface
• Posterior teeth  boundary of occlusal surface
2. Triangular ridge
• Ridges that run from the tips of the cusps
of premolars and molars toward the centre
of the occlusal surfaces
3.Transverse ridges
• Formed by 2 triangular ridges (buccal and
lingual )
• Join transversely across the occlusal
surfaces of the posterior teeth
4.Oblique ridge
• Ridge, that runs obliquely on the occlusal
surfaces
• Union of triangular ridge of the disto-buccal
cusp and the distal ridge of the mesio-palatal
cusp
5.Labial Ridge
• Vertical
• Cervico-incisal direction
• Labial surface of canine
6.Lingual Ridge
• Vertical
• Cervico-incisal direction
• Lingual surface
• Divides lingual fossa into Mesial and Distal
7.Buccal Ridge
• Vertical
• Cervico-occlusal direction (premolars)
• Prominent  1st Premolars
8.Cervical Ridge
• Horizontal
• Mesio-distal direction
• Cervical one-third of the buccal surface
9.Cusp ridges
• Mesial and Distal slopes of the cusps
10.Linguo-Incisal Ridge
• Horizontally Mesio-distal direction
• Incisal one-third (Lingual surface) of upper
incisors
Fossa
• Irregular depression or concavity found on
the lingual surface of anterior teeth or
occlusal surface of posterior tooth
• Fossae can be
1. Lingual fossa
2. Central fossa
3. Distal fossa
4. Triangular fossa
Lingual fossa
• lingual surface of anterior teeth,
• bounded by marginal ridges, cingulum and
linguo-incisal ridge.
• canines are divided in to two by lingual
ridge.
• A central fossa: is found on the occlusal
surface of a molars which are formed by the
converging of ridges terminating at a central
point in the bottom of a depression where there
is a junction of grooves.
• Triangular fossae -molars and premolars
on the occlusal surfaces just inside the
marginal ridges.
• two triangular fossae including mesial
triangular fossa
• A sulcus is a broad linear depression or valley
on the surface of a posterior tooth.
• Sulcus is the area between ridges and cusps,
the inclines of which meet at an angle to form
a groove called as developmental groove.
•
• A groove is a linear depression or a line
present at the deepest part of the sulcus.
• developmental grooves / supplemental
grooves
• Developmental grooves
• sharply defined, narrow and linear
depression seen separating major portions
of a tooth developing from different lobes.
• A supplemental groove is a small
irregularly placed shallow groove which is
less distinct
• not found between major portions of a
tooth.
• Pits pinpoint depressions located at the
junction of developmental grooves or at
terminals of those grooves.
• Pits - found at the deepest part of fossae,
• Fissure is a cleft or ditch formed at the
bottom of a developmental groove.
Lobe
• Primary sections of formation in the
development of the crown
Deciduous
• Incisors  1 lobe
• 2nd Molar  5 lobes
Permanent teeth
• Anteriors  4 lobes
• Premolars  4 lobes
• Molars  number of lobes = number of cusps
Mamelons
• 3 protruberances found on the incisal
ridges of newly erupted incisor teeth
• Root trunk –the undivided cervical
portion of the root of multirooted teeth.
• Furcation is the division of the root of the
multirooted teeth.
• When the root is dividing in to two it is
referred to as bifurcation and when three,
trifurcation.
• Apical and accessory foramen are small
openings found at the apical region of root
through
• Contact point or contact areas
• Contact areas are the places on the
proximal surfaces of tooth crowns where a
tooth touches the adjacent tooth in the
same arch,
• Functions of contact
• Contact area helps to prevent food
wedging during mastication,
• maintain the arch length,
• Contours are curvatures that are seen on
the cervical or middle third on the facial or
lingual aspect of all the teeth in dental
arch.
• Height of contour or crest of curvature
is an imaginary curved line encircling a
tooth at its greatest bulge.
• Embrasures (spillways) are triangular or Vshaped spaces seen facial, lingual or
occlusal to the contact areas.
• Functions of embrasures
• allow food to be forced away from contact areas
and thus keep food from being packed between
them.
• help to dissipate and reduce occlusal forces.
• protecting the gingiva from undue trauma.
Chronology and Sequence of
Eruption
Crown and Root
• Crown is covered by enamel
• Root portion covered by cementum
• Crown and root will join with CEJ
• Four tooth tissue are there Enamel , Dentin ,
Cementum- hard tissue
• Pulp – soft tissue
• Crown of incisors – Incisal ridge or edge
• Single cusp – canine
• Two or more cusp – PM and molars
• Root – single – incisors and Canine
• Multiple roots – PM and Molars
• Portion of the jaw serving as support for the tooth –
Alveolar process
• Soft tissue which covers the cervical 1/3 of the tooth
– Gingiva or Gums
Surfaces and Ridges
• Crowns of the teeth will have surfaces
• Surfaces named according to their position –
• Labial , Lingual , Mesial , distal and Incisal
• Four teeth will have mesial surface that contact each other
named as Maxillary and Mandibular incisors
• Contact area – area of the mesial and distal surface of a tooth
that touches its neighbor in the arch
Other land marks
•
•
•
•
•
•
•
•
Cusp
Tubercle
Cingulum
Ridge
Marginal ridge
Triangular ridge
Transverse ridge
Oblique ridge
•
•
•
•
•
•
Fossa
Sulcus
Developmental groove
Supplemental groove
Pit
lobe
• Cusp –
• Elevation or mound on the crown portion of a tooth
• Tubercle –
• Smaller elevation on some portion of the crown
produced by an extra formation of the enamel
• Cingulum –
• It is also called as girdle – lingual lobe of an anterior
tooth and makeup the bulk of the cervical third of the
lingual surface at the cervical one third
• Ridge –
• Linear elevation on the surface of a tooth and named
according to location – Buccal , Incisal or marginal
ridge
• Marginal ridges –
• Rounded border of the enamel that form the mesial
and distal margins of the occlusal surface of the PM
and molars
• Mesial and distal margins of the lingual surfaces of
the incisors and canines
• Triangular ridges –
• It descends from the tip of the cusps of posterior teeth
towards the central part of the occlusal surface
• Transverse ridge –
• buccal and lingual triangular ridges joins
• It form by union of two triangular ridges transversely
crossing the surface of a posterior tooth
• Oblique ridge –
• It runs obliquely crossing the occlusal surface of
maxillary molars
• Union of the triangular ridge of the distobuccal cusp
and distal cusp ridge of the mesiolingual cusp
• Fossa –
• Irregular depression or concavity
• Lingual fossae – lingual surface of incisors
• Central fossae – convergence of ridges terminating at
a central point in the bottom of the depression where
a junction of grooves occur
• Triangular fossae – occlusal surface of posterior teeth
• Sulcus –
• Long depression or valley in the surface of a tooth
between ridges and cusps, the inclines of which meet
at an angle
• Developmental depression –
• Shallow groove or line between the primary parts of
the crown and root
• Supplemental groove – less distinct , shallow linear
depression on the occlusal surface of a tooth
• Buccal and lingual developmental grooves – found on
the buccal and lingual surface of posterior teeth
• Pits –
• Small pinpoint depression located at the junction of
developmental grooves
• Central pits – landmark of the central fossa of molars
where developmental grooves are join
• Lobe –
• Primary section of formation in the development of
crown
• Mamelon –
• Any one of the three rounded protuberance found on
the Incisal ridges of newly erupted incisor teeth
• Roots –
• Single or multiple
Division into thirds
• Purpose of description crown and root divided into
three portions
• Crown –
• Labial – cervical, middle , Incisal / Distal , Middle ,
Mesial
• Mesial aspect – Labial ,Middle , Lingual
• Posterior teeth – cervical , middle and occlusal
• Root – cervical , Middle , Apical
Line angles
• Junction of two surfaces ( Ex – mesial and Labial) –
Mesioincisal line angle
• Line angles of the anterior teeth
• Mesiolabial ,
• Distolingual ,
• Distolabial ,
• Labioincisal ,
• Mesiolingual ,
• Linguo incisal
Line angles of the Posterior teeth
•
•
•
•
•
•
•
•
Mesiobuccal
Distobuccal
Mesiolingual
Distolingual
Mesioocclusal
Distoocclusal
Bucco occlusal
Lingual occlusal
Point angles
• Junction of three surfaces
• Point angles of the anterior teeth
• Mesiolabial incisal
• Mesiolinguoincisal
• Distolabial incisal
• distolinguoincisal
• Point angles of the posterior teeth
• Mesiobuccaoocclusal
• Mesiolinguo occlusal
• Distobucco occlusal
• Distolingual occlusal
Methods of Measuring of tooth