Dental Anatomy and Dental Anatomy and MorphologyMorphology

Revision LectureRevision Lecture

Contents

1 .Surfaces of teeth

2 .Line angles and point angles

3 .Depressions and Elevations on teeth

4 .Division in thirds

Objectives

The prime objective of this lecture is to revise the dental terminology.

Learning nomenclature is the first and very Learning nomenclature is the first and very important step in understanding dental anatomy. important step in understanding dental anatomy.

To study and facilitate communication various To study and facilitate communication various surfaces of teeth are recognized and given surfaces of teeth are recognized and given names.names.

Surfaces of teethSurfaces of teethCrowns of all teeth have five surfacesCrowns of all teeth have five surfaces..

11 . .Facial SurfaceFacial Surface

Facial surface can be labial surface or buccal Facial surface can be labial surface or buccal surfacesurface..

a. Labial surface.a. Labial surface. The surfaces of incisors and The surfaces of incisors and canines that are towards the lipcanines that are towards the lip..

b. Buccal surface.b. Buccal surface. The surfaces of premolars and The surfaces of premolars and molars that face the cheekmolars that face the cheek..

22 . .Lingual Surface (Palatal surface)Lingual Surface (Palatal surface)All surfaces facing towards the tongueAll surfaces facing towards the tongue..

palatal

33 . .Proximal SurfacesProximal Surfaces

a. Mesial Surfacea. Mesial SurfaceAll surfaces towards the midlineAll surfaces towards the midline..

b. Distal Surfaceb. Distal SurfaceAll surfaces away from the midline. Mesial surface All surfaces away from the midline. Mesial surface and Distal surface are collectively called and Distal surface are collectively called proximal proximal surfacesurface..

Proximal surfaces

44 . .Incisal or Occlusal surfaceIncisal or Occlusal surface

a. Incisal surface.a. Incisal surface. The surface of incisors and canines that come in contact with those The surface of incisors and canines that come in contact with those in the opposite jaws during the act of closure are called incisal surfacesin the opposite jaws during the act of closure are called incisal surfaces

b. Occlusal surface.b. Occlusal surface. The surface of premolars and molars that come in contact with The surface of premolars and molars that come in contact with those in the opposite jaws during the act of closure are called occlusal surfacesthose in the opposite jaws during the act of closure are called occlusal surfaces..

Maxillary Arch

Mandibular Arch

43 2

1 1

1 .Labial surface

2 .Mesial surface

3 .Distal surface

4 .Incisal surface

3

3

32 1

1 .Buccal surface2 .Lingual

surface3 .Occlusal

surface

Line and Point anglesLine and Point anglesWhen two of these surfaces meet, a When two of these surfaces meet, a

line angle is formed and when three line angle is formed and when three surfaces meet a point angle is surfaces meet a point angle is formedformed

Line angle

Point angle

Line angles of anterior teethLine angles of anterior teeth1. Mesiolabial1. Mesiolabial2. Disto labial2. Disto labial3. Mesiolingual3. Mesiolingual4. Distolingual4. Distolingual

55 . .LabioincisalLabioincisal66 . .LinguoincisalLinguoincisal

LabioincisLabioincisalal Linguo Incisal

Mesio labialMesio labial

Disto labialDisto labial

Mesio Mesio linguallingual Disto Disto

linguallingual

Line angles of Anterior teeth

Line angles of posterior teeth

1 .Mesiobuccal

2 .Distobuccal

3 .Mesiolingual

4 .Distolingual

5 .Mesio-occlusal

6 .Disto-occlusal

7 .Bucco-occlusal

8 .Linguo-occlusal

Line angles of Posterior teeth

Point angles of anterior teethPoint angles of anterior teeth

1.1. MesiolabioincisalMesiolabioincisal

2.2. DistolabioincisalDistolabioincisal

3.3. MesiolinguoincisalMesiolinguoincisal

4.4. DistolinguoincisalDistolinguoincisal

Point angles of Anterior teeth

MLa

L

D

Point angles of posterior teethPoint angles of posterior teeth

1.1. Mesiobucco-occlusalMesiobucco-occlusal

2.2. Distobucco-occlusalDistobucco-occlusal

3.3. Mesiolinguo-occlusalMesiolinguo-occlusal

4.4. Distolinguo-occlusalDistolinguo-occlusal

Point angles of Posterior teeth

Depressions on tooth surfaceDepressions on tooth surface

11 . .Pit. Pit. A sharp pinpoint depression on the surface A sharp pinpoint depression on the surface of the enamelof the enamel

22 . .FossaFossa. An irregular depression or concavity on . An irregular depression or concavity on the surface of a tooththe surface of a tooth..

21

1 .Pit2 .Fossa

33 . .SulcusSulcus . .

A long depression on the surface of a toothA long depression on the surface of a tooth..

4. Groove4. Groove is a shallow linear depression on the surface of a is a shallow linear depression on the surface of a tooth. tooth.

A A developmental groovedevelopmental groove is a shallow groove or line between the primary is a shallow groove or line between the primary parts of the crown or root. parts of the crown or root.

A A supplemental groove supplemental groove is less distinct and does not mark the junction of is less distinct and does not mark the junction of primary parts.primary parts.

1

1 .Developmental grooves

Elevations on tooth surfaceElevations on tooth surface

11 . .CuspCusp. An elevation or mound on the crown of a . An elevation or mound on the crown of a toothtooth..

C

C

C

C

C

C

Cusps

2. Cingulum 2. Cingulum is the lingual lobe of an anterior tooth is the lingual lobe of an anterior tooth and makes up the bulk of the cervical third of the and makes up the bulk of the cervical third of the lingual surface.lingual surface.

C

Cingulum

3. Lobe3. Lobe is one of the primary sections of formation in is one of the primary sections of formation in the development of the crown. Cusps and mamelons the development of the crown. Cusps and mamelons are representative of lobes.are representative of lobes.

4. Mamelons4. Mamelons are three rounded protuberances found are three rounded protuberances found on the incisal ridges of newly erupted incisor teeth.on the incisal ridges of newly erupted incisor teeth.

RidgeRidge. A linear elevation on the surface of a tooth. A linear elevation on the surface of a tooth

Marginal ridgesMarginal ridges are rounded borders of enamel that are rounded borders of enamel that form the mesial and distal margins of the occlusal form the mesial and distal margins of the occlusal surfaces of posterior teeth and the mesial and distal surfaces of posterior teeth and the mesial and distal margins of the lingual surfaces of anterior teeth.margins of the lingual surfaces of anterior teeth.

Triangular ridgeTriangular ridge is a ridge that descends from the is a ridge that descends from the tips of the cusps of molars and premolars towards tips of the cusps of molars and premolars towards the centre part of the occlusal surface.the centre part of the occlusal surface.

Transverse ridge Transverse ridge is formed by the union of buccal is formed by the union of buccal and lingual triangular ridgesand lingual triangular ridges..

Oblique ridgeOblique ridge is a ridge obliquely crossing the is a ridge obliquely crossing the occlusal surfaces of maxillary molars.occlusal surfaces of maxillary molars.

1

1

2

2

3 1

1

1 .Marginal ridge2 .Triangular ridge

3 .Oblique ridge

Occlusal aspect of Maxillary Molar

Occlusal aspect of Mandibular Molar

Other important termsOther important termsMid line.Mid line. An imaginary line dividing the upper and An imaginary line dividing the upper and lower arches into two equal halveslower arches into two equal halves..

Anterior.Anterior. Pertaining to or towards the front plane of the Pertaining to or towards the front plane of the bodybody..

Posterior.Posterior. Pertaining to or towards the back plane of Pertaining to or towards the back plane of the bodythe body..

Superior. Superior. Situated above another or towards the headSituated above another or towards the head..

Inferior.Inferior. Situated beneath another or towards the feet Situated beneath another or towards the feet..

Anterior Teeth

Posterior Teeth

Division in thirdsDivision in thirdsTo make study and communication easier the crown To make study and communication easier the crown and root are divided into three halvesand root are divided into three halves..

Division in thirds occluso-gingivally (Crown)Division in thirds occluso-gingivally (Crown)

11 . .Cervical thirdCervical third

22 . .Middle thirdMiddle third

33 . .Incisal/Occlusal thirdIncisal/Occlusal third incisal

Middle

cervical

cervical

Occlusal

Middle

Division in thirds facio-lingually (Crown)Division in thirds facio-lingually (Crown)

Crown when viewed from frontCrown when viewed from front

11 . .Mesial thirdMesial third

22 . .Middle thirdMiddle third

33 . .Distal thirdDistal third

Distal

Middle

Mesial

Mesial

Middle

Distal

M D

Mesial

Middle

Distal

M D

Division in thirds facio-lingually (Crown)Division in thirds facio-lingually (Crown)Crown when viewed from the sideCrown when viewed from the side

11 . .Facial thirdFacial third

22 . .Middle thirdMiddle third

33 . .Lingual thirdLingual third

Division in thirds-rootDivision in thirds-root11 . .Cervical thirdCervical third

22 . .Middle thirdMiddle third

33 . .Apical thirdApical third

A

M

C

AA

M M

C

C – CervicalM – MiddleA – Apical

THANK YOUTHANK YOU