Introduction to Dental Introduction to Dental AnatomyAnatomy

Dental AnatomyDental AnatomyDr. Firas Alsoleihat, BDS, PhDDr. Firas Alsoleihat, BDS, PhDDepartment of Conservative Department of Conservative

DentistryDentistry

IntroductionIntroduction

• Human dentition is diphyodontHuman dentition is diphyodont– 2 sets of dentitions2 sets of dentitions

•Primary/deciduousPrimary/deciduous– 20 teeth in total20 teeth in total– Incisors/canines/molarsIncisors/canines/molars– Smaller sizeSmaller size

•Secondary/permanentSecondary/permanent– 32 teeth in total32 teeth in total– Incisors/canines/premolars/molarsIncisors/canines/premolars/molars– Bigger sizeBigger size

Deciduous & permanent Deciduous & permanent dentitionsdentitions

• Why do Why do we have we have to have to have 2 sets of 2 sets of teeth?teeth?

Why 2 sets of Why 2 sets of dentitions?dentitions?•The jaws have to The jaws have to

accommodate the accommodate the increased number of increased number of permanent teeth and their permanent teeth and their bigger sizebigger size

Dental formulaDental formula– I for incisorsI for incisors–C for CaninesC for Canines–PM for premolarsPM for premolars–M for molarsM for molars–Deciduous teeth are Deciduous teeth are indicated by the letter D indicated by the letter D before the initialbefore the initial

Human dental Human dental formulaformula•Deciduous teethDeciduous teeth

– DI 2/2 DC 1/1 DM 2/2 = 10DI 2/2 DC 1/1 DM 2/2 = 10

•Permanent teethPermanent teeth– I 2/2 C 1/1 PM 2/2 M 3/3 = 16I 2/2 C 1/1 PM 2/2 M 3/3 = 16

The numbers following the letter refer to the The numbers following the letter refer to the number of teeth of each type in the upper then number of teeth of each type in the upper then the lower dentition for one side only the lower dentition for one side only

QuadrantsQuadrants• Tooth-bearing region of the jaw can Tooth-bearing region of the jaw can

be divided into 4 quadrantsbe divided into 4 quadrants– Right maxillary (1 or 5)Right maxillary (1 or 5)– Left maxillary (2 or 6)Left maxillary (2 or 6)– Left mandibular (3 or 7)Left mandibular (3 or 7)– Right mandibular (4 or 8)Right mandibular (4 or 8)

Quadrants in permanent dentition have the Quadrants in permanent dentition have the numbers 1 - 4 and in deciduous have the numbers 1 - 4 and in deciduous have the numbers 5 - 8numbers 5 - 8

QuadrantsQuadrants

1 or 5 2 or 6

4 or 8 3 or 7

Teeth orderTeeth order

• Each tooth in a quadrant takes a Each tooth in a quadrant takes a letter (A – E for deciduous) or a letter (A – E for deciduous) or a number (1 – 8 for permanent) number (1 – 8 for permanent) indicating its order when counting indicating its order when counting from the midlinefrom the midline

8 7 6 5 4 3 2 1

8 7 6 5 4 3 2 1

1 2 3 4 5 6 7 8

1 2 3 4 5 6 7 8

E D C B A

E D C B A A B C D E

A B C D E

Dental nomenclatureDental nomenclature• By wordsBy words

– SetSet• Deciduous or permanentDeciduous or permanent

– JawJaw• Maxillary or mandibularMaxillary or mandibular

– ClassClass• Incisor/canine/premolar/molarIncisor/canine/premolar/molar

– Order within a classOrder within a class• Central or lateralCentral or lateral• First/second/thirdFirst/second/third

– SideSide• Right or leftRight or left

• By numbers, letters and/or symbolsBy numbers, letters and/or symbols– Palmer notation systemPalmer notation system– Universal numbering systemUniversal numbering system– FDI numbering systemFDI numbering system

Palmer/Zsigmondy notation Palmer/Zsigmondy notation systemsystem

• American Dental Association in 1947American Dental Association in 1947• Tooth is represented by a number 1 – 8 Tooth is represented by a number 1 – 8

(permanent) or a letter A – E (deciduous)(permanent) or a letter A – E (deciduous)• Two lines; indicates which quadrant the tooth Two lines; indicates which quadrant the tooth

belongs tobelongs to– a horizontal representing the occlusal plane and a horizontal representing the occlusal plane and – a vertical representing the midlinea vertical representing the midline

• Examples:Examples:– Maxillary right central incisorMaxillary right central incisor– Mandibular left second deciduous molarMandibular left second deciduous molar

1

E

E D C B AE D C B A

A B C D E

A B C D E

8 7 6 5 4 3 2 18 7 6 5 4 3 2 1

1 2 3 4 5 6 7 8

1 2 3 4 5 6 7 8

Universal numbering systemUniversal numbering system• Palmer – difficulty in keyboard typingPalmer – difficulty in keyboard typing

• ADA adopted the universal system in 1968ADA adopted the universal system in 1968

• Uppercase letters for deciduous teethUppercase letters for deciduous teeth– Consecutive from A to TConsecutive from A to T– Following a clockwise order from maxillary right second Following a clockwise order from maxillary right second

molar to mandibular right second molarmolar to mandibular right second molar

• Numbers for permanent teethNumbers for permanent teeth– Consecutive from 1 to 32Consecutive from 1 to 32– Following a clockwise order from maxillary right third Following a clockwise order from maxillary right third

molar to mandibular right third molarmolar to mandibular right third molar

A B C D ET S R Q P

O N M L K

F G H I J 1 2 3 4 5 6 7 832 31 30 29 28 27 26 25

24 23 22 21 20 19 18 17

9 10 11 12 13 14 15 16

FDI numbering systemFDI numbering system

• Proposed by FDI & adopted by WHOProposed by FDI & adopted by WHO

• Each tooth is allocated a two-digit number; Each tooth is allocated a two-digit number; the left designates the quadrant and the the left designates the quadrant and the right designates the tooth order right designates the tooth order

• ExamplesExamples– Mandibular right permanent canine 43Mandibular right permanent canine 43– Maxillary left deciduous lateral incisor 62Maxillary left deciduous lateral incisor 62

55 54 53 52 51

85 84 83 82 81

71 72 73 74 75

61 62 63 64 65

18 17 16 15 14 13 12 11

48 47 46 45 44 43 42 41

21 22 23 24 25 26 27 28

31 32 33 34 35 36 37 38

Types of dentitions: Types of dentitions:

• Diphyodont. Most mammals--humans Diphyodont. Most mammals--humans included--typically develope and erupt included--typically develope and erupt into their jaws two generations of into their jaws two generations of teeth. The term literally means "two teeth. The term literally means "two generations of teeth." generations of teeth."

• Monophyodont. Some mammals--such Monophyodont. Some mammals--such as the manatee, seals, and walruses as the manatee, seals, and walruses have only a single generation of teeth. have only a single generation of teeth.

• Polyphyodont. Most reptiles and Polyphyodont. Most reptiles and fishes develope a lifetime of fishes develope a lifetime of generations of successional teeth--generations of successional teeth--Such teeth have a brief functional life Such teeth have a brief functional life and are anatomically simple in and are anatomically simple in design. design.

• Homodont. In many vertebrates, all Homodont. In many vertebrates, all of the teeth in the jaw are alike. They of the teeth in the jaw are alike. They differ from each other only in size. differ from each other only in size. The alligator is an example of The alligator is an example of homodontism. homodontism.

• Heterodont. Most mammals, humans Heterodont. Most mammals, humans included, develope distinctive classes of included, develope distinctive classes of teeth that are regionally specialized. teeth that are regionally specialized. We will discuss classes of teeth in the We will discuss classes of teeth in the next unit. next unit.

• Anodontia is the developmental Anodontia is the developmental absence of teeth. Among mammals, the absence of teeth. Among mammals, the whalebone whale and the anteater are whalebone whale and the anteater are toothless; their ancestors had teeth. In toothless; their ancestors had teeth. In humans, anodontia is a pathological humans, anodontia is a pathological condition. Partial anodontia is one or a condition. Partial anodontia is one or a few teeth missing. few teeth missing.