introduction to pediatric dentistry€¦ · 1st molar 14 months 5 2nd molar 24 months 9 mandibular...

PRE-CLINICAL PEDIATRIC DENTISTRY

DSV 342 Development and Morphology of primary teeth

2 Professor Othman Al-Ajlouni

Salman Bin Abdul Aziz University18-Dec-11111-Nov-14 Monday 6/2/2012 1:00 pm-2:00 pm

Tuesday, November 11, 2014 1 Professor Othman Al-Ajlouni

Pediatric Dentistry

"Pediatric Dentistry is an age-defined specialty that provides primary and comprehensive preventive and therapeutic oral health care for infants and children through adolescence, including those with special health care needs."

Tuesday, November 11, 2014 Professor Othman Al-Ajlouni 2

What are the key elements of this definition, that make it so unique? • "age-defined": most specialties are procedure defined

(endodontics, periodontics, etc.). Pediatric dentists provide care for their specific age group of patients. There is no limitation to what type of treatment they provide.

• "primary and comprehensive...care": Pediatric dentists are primary providers. There is no need for a referral of patients.

• "infants and children through adolescence": Pediatric dentists see patients at any age from birth up to their late teens.

• "special health care needs": Pediatric dentists have the training and experience to evaluate and treat patients, that are medically compromised. This includes patients with hemophilia, leukemia, congenital syndromes, etc... Tuesday, November 11, 2014 Professor Othman Al-Ajlouni 3

About primary teeth

• Start appearing in the mouth between ages 6 months to 2.5 years

• They are called deciduous meaning to “fall off”,

• Other names include temporary , and milk teeth


General Information

• 20 primary teeth, 10 in each jaw

• Teeth are :

– central incisors, lateral incisors, canines, first primary molars, second primary molars.

(A, B, C, D, E)

• Sequence of eruption in deciduous dentition:

A, B, D, C, E.


Importance of primary teeth

• Efficient mastication and proper diet

• Normal esthetic facial appearance

• Formulation of clear speech

• Avoidance of infection which may lead to dark spots on permanent successors called “Turner’s spots”

• Maintenance of space for permanent successors, and arch continuity.


Sequence of eruption

• Lower central incisor

• upper central incisor,

• Lower lateral incisor

• upper lateral incisor,

• Lower primary first molar,

• Upper primary first molar

• Lower and upper primary canines

• Lower and upper primary second molars.


Eruption time and sequence

Tooth Eruption date Sequence

Maxillary

teeth Central incisor 7 ½ months 2

Lateral incisor 9 months 3

Canine 18 months 7

1st molar 14 months 5

2nd molar 24 months 9

Mandibular

teeth Central incisor 6 months 1

Lateral incisor 7 months 2

Canine 16 months 6

1st molar 12 months 4

2nd molar 20 months 8


General characteristics

• 1- smaller in size and whiter in color than permanent

• 2- shorter crowns compared to roots

• 3- marked constriction at the cervix of the crown as if squeezed by rubber band

• 4- Enamel and dentine are thinner, and pulp cavities are larger

• 5- Crowns are bulbous having labial bulges.

• 6- Narrower occlusal table


Differences between primary and permanent teeth

• A=enamel thinner • b=pulp chamber larger • C=pulp horns higher • D=cervical ridge more

pronounced • E=enamel rods slope

occlusally • F=constricted neck • G=roots longer compared to

crown • H=roots more flared and

furcation closer to the cervical line


Pulp of Primary teeth

• Larger in relation to the crown size.

• Horns are closer to the outer surface of the tooth.

• Mesial pulp horn extends to a closer approximation of the surface than does the distal pulp horn of the primary tooth

• Mandibular molar has larger pulp chambers than maxillary molar.

• Form of pulp chamber follows the surface of the crown.

• Usually pulp horn under each cusp.


Primary Vs. Permanent


Primary incisors Labial aspect

• Upper central is wider mesiodistally than incisocervically

• Roots are longer compared to crowns

• Incisal edge flat, rounded distoincisal angle

• Lateral is smaller and rounder than central

• Lower incisors much smaller, but similar shape

• Contact area location similar to permanent

Labial Surface (Right side)


Primary incisors

• Lingual aspect:

– Cingulum and marginal ridges are pronounced in maxillary teeth, less prominent in mandibular teeth

– The roots, and the crowns taper lingually

– The cross section of the root is triangular in shape (labial, mesial and distal)


Primary Incisors Proximal Aspect

• The curvature of cervical line is very prominent (CEJ) curving incisally.

• Curvature distally is less than mesially

• Maxillary Incisors: Mesial side of the root has developmental groove (concave), distal part of the root is convex

• Mandibular Incisors: Differs from upper in that the distal surface of root has depression and mesially it is flat.


Primary canines labial aspect

• Incisal edge differs from centrals (Prominent cusp)

• The maxillary canines is much larger labiolingually than the mandibular canines.

• Maxillary Canines: The mesial cusp slope is much longer than the distal cusp slope

• Mandibular Canines: The distal cusp slope is much longer than the mesial cusp slope.

Labial Surface (Right side)


Primary canines lingual aspect

• Well developed cingulum and mesial and distal marginal ridges

• A lingual ridge is more pronounced on the maxillary than mandibular canine.

• Mesial and distal lingual fossae are present , the distal one is deeper and narrower than the mesial one


Primary canines proximal aspect

• Cervical third is thick due to prominent ridges and cingula (more than incisors)

• Position of cusp tip same as for incisors

• Cervical line curves incisally more on the mesial aspect


Primary canines incisal aspect

• Incisal outline is diamond shape, more obvious in lower canine

• Noticeable lingual taper

• Cingulum centered mesiodistally

• From this view, the labial surface is slightly convex and the lingual is slightly concave.


Primary molars General concepts

• Primary second molars resemble permanent first molars, the main difference is in the prominent cervical ridges on of primary molars.

• Primary 1st molars are smaller than 2nd molars

• Primary 1st molars are unique in shape, the lower first molar resembles no other tooth in the dental arch

• Maxillary molars have three roots, mandibular have two


Primary maxillary molars Buccal aspect

• Mesiodistal dimention > cervicoocclusal dimention

• Two buccal cusps, a large mesiobuccal and a smaller distobuccal (much smaller in 1st molar)

• Three roots can be seen on this aspect (Distobuccal shorter than mesiobuccal)


Primary maxillary molars lingual aspect

• On the first primary molars one large mesiolingual cusp is seen and a much smaller or even absent distolingual cusp.

• On the 2nd molar distolingual cusp is smaller than mesiolingual cusp, but always present

• The lingual root is the largest.


Primary maxillary molars proximal aspect

• Prominent cervical bulge on the buccal aspect causing the outline of crown to taper sharply towards occlusal.

• Lingual outline is more uniformly convex

• When we look mesially, we see only lingual and mesiobuccal roots.

Mesial Surface (Right side)


Primary maxillary 1st molar occlusal aspect

• Rectangular outline with rounded mesiolingual corner. So MMR runs obliquely in distolingual direction.

• In the 4-cusp type, transverse ridge forms between the DB and ML cusps (Oblique Ridge)

• Three fossae: MTF, CF, DTF according to size , each with a pit M,D,C.

• Grooves: form H pattern, formed by CDG, supplemental grooves inside MMR, and BDG+DLG


Primary maxillary 2nd molar occlusal aspect

• Distolingual corner tapers sharply towards the distal , so the oblique ridge is straighter buccoligually.

• MBC equal in size or slightly larger than MLC, then comes in size the DBC and smallest is DLC.

• A fifth cusp may be present.

• Grooves: as in diagram


Primary mandibular molars buccal aspect

• Mesiodistal dimention > cervicoocclusal dimention

• Two buccal cusps, a large mesiobuccal and a smaller distobuccal in 1st molar.

• 2nd molar :3 buccal cusps

• Cusps are separated by a groove on 2nd molar and a depression on 1st molar

• Very prominent cervical ridge esp on 1st molar


Primary mandibular molars lingual aspect

• Two cusps are seen ML and DL, which are separated by a groove both are longer than buccal cusps, ML cusp is larger than DL cusp,

• Well developed mesial MR

• Cervical line is much straighter than from the buccal surface.


Primary mandibular molars proximal aspect

• Prominent cervical ridges and MMR are seen on mesial aspect

• The crown appears to be tapering lingually as with all lower teeth

• The buccal outline above cervical ridge is flat towards cusp tip.

• Mesial root is wider, and longer and has a depression mesially

Mesial Surface (Right side)


Primary mandibular 1st molar occlusal aspect

• MB angle is acute due to prominent cervical ridge

• Occlusal table is small, and rhomboid in shape

• Cusps from bigger to smaller, ML, MB, DB, DL

• Grooves: CG, LG, BG

• Small MTF, larger DTF


Primary mandibular 2nd molar occlusal aspect

• The three buccal cusps nearly equal in size, the largest is DBC

• Lingual cusps equal in size, & shorter than buccal cusps

• Grooves: see diagram


Development and Morphology of primary teeth

• Life cycle of the tooth.

• Early development and calcification of anterior primary teeth.

• Early development and calcification of posterior primary teeth and the first permanent molar.

• Morphology of individual primary teeth.

• Morphologic differences between primary and permanent teeth.

• Size and morphology of the primary tooth pulp chamber.


LIFE CYCLE OF THE TOOTH

• Initiation (Bud Stage)

• Proliferation (Cap Stage)

• Histodifferentiation and Morphodifferentiation (Bell

Stage)

• Apposition

• Calcification



Life cycle of the tooth.


Development of deciduous dentition.



• Life cycle of the tooth.

• Early development and calcification of anterior primary teeth.

• Early development and calcification of posterior primary teeth and the first permanent molar.

• Morphology of individual primary teeth.

• Morphologic differences between primary and permanent teeth.

• Size and morphology of the primary tooth pulp chamber.


Eruption

• Mechanisms of tooth eruption are complex

• Teeth eventually appear in mouth through

a combination of growth of supporting

bone

• Elongation of tooth root and growth of pulp

Tuesday, November 11,

2014

Professor Othman Al-Ajlouni 37

Eruption

• Mechanisms of tooth eruption are complex

• Teeth eventually appear in mouth through

a combination of growth of supporting

bone

• Elongation of tooth root and growth of pulp


2014


Nutrition and Teeth

• Prenatal nutrition and developing teeth

– Prenatal nutrition has very little effect on the

developing tooth

– Primary teeth begin to calcify in utero

– Relatively protected from lack of calcium

– Mother provides calcium needed during

pregnancy

– Ingestion of tetracyclines and high flouride

levels by mother causes discoloration in utero


2014


Prerequisite knowledge

• Growth & development of face and jaws both prenatal and postnatal

• Eruption of teeth timing and sequence

• Morphology of teeth both primary and permanent

• Terminology of key words

• Masticatory movements and path of closure of the mandible


2014


definition of terms used

• Deciduous dentition

• mixed dentition

• Permanent dentition

• Predecessor

• Successor


2014


Eruption of deciduous incisors.

• During the first year, the gum pads enlarge

and arches widen to provide space for

erupting incisors.

• Timing of eruption 6 month variation

• premature eruption of teeth natal and

neonatal teeth.


2014


Sequence of eruption

• Lower central incisor

• upper central incisor,

• Lower lateral incisor

• upper lateral incisor,

• Lower primary first molar,

• Upper primary first molar

• Lower and upper primary canines

• Lower and upper primary second molars.


2014


Primary dentition.


2014


Typical features of primary

dentition

• Colour - whiter than permanent teeth

• Size incisors and canines are smaller than

permanent teeth


2014


Typical features of occlusion of

primary dentition.

.

• Incisors are upright

• Primate space present

• positive over jet and over bite

• each maxillary tooth occlude with two

mandibular teeth.

• Distal surfaces of primary second molars

in same vertical plane.


2014


Primary dentition.


2014


Development of occlusion

• Mixed dentition stage 6-12 years


2014


Beginning of the mixed dentition

• Lower first molar erupt around six years.


2014


Mixed dentition begins with

eruption of first molars.


2014


Introduction To Pediatric Dentistry Differences Between A Deciduous Tooth and

A Permanent Tooth • Features of a Deciduous Crown

• Features of a Deciduous Pulp

• Features of a Deciduous Root


Introduction To Pediatric Dentistry

Differences Between A Deciduous Tooth and A Permanent Tooth

• Features of a Deciduous Crown

1. Shorter crown

2. Narrower occlusal table

3. Constricted cervical portion

4. Thinner enamel and dentin

5. Enamel rods in the gingival third extend occlusally from the DE junction

6. Broad and flat contact areas

7. Lighter color


Introduction To Pediatric Dentistry Differences Between A Deciduous Tooth and A Permanent Tooth

• Features of a Deciduous Pulp

1. Larger pulp in relation to the crown size

2. Pulpal horns closer to the outer surface of the tooth

3. Larger pulp chamber in the mandibular molar than does the maxillary

4. Pulp chamber form follows the surface of the crown

5. Usually there is a pulp horn under each cusp

6. Thin and slender roots pulp, thin pulp canals

7. Accessory canal extend from the floor of the pulp chamber to the furcation area

8. Increased blood supply

9. Increased internal resorption

10. Reduced sensitivity to pain due to less number of nerve fibers

11. Multiple ramification

12. Ribbon shaped root canal that narrower mesiodistally

13. Increased reparative dentin formation


Introduction To Pediatric Dentistry Differences Between A Deciduous Tooth and A Permanent Tooth

• Features of a Deciduous Root

1. Narrower root mesiodistally in the anterior teeth

2. Longer and more slender in relation to crown of the posterior teeth

3. Flare more as they approach the apex


Introduction To Pediatric Dentistry

References 1. McDonald RE, Avery DR, Dean JA. Dentistry for the Child and Adolescent, 8th

Ed. New York, NY, 2005, Mosby.


introduction to pediatric dentistry€¦ · 1st molar 14 months 5 2nd molar 24 months 9 mandibular...

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