Anatomy of Primary Teeth

	Steven Chussid D.D.S.

Lecture Overview

	Primary Dentition
	General Morphological considerations
	Implications of Primary tooth morphology

Primary Dentition

	20 primary teeth as compared to 32 permanent teeth
	No premolars in the primary dentition
	The primary molars are replaced by the premolars
	The permanent molars erupt distal to the primary second molars

General Morphologic considerations

	Crown
	Pulp
	Root

Crown of Primary Teeth

	Shorter
	Narrower occlusal table
	Constricted in the cervical portion
	Thinner enamel and dentin layers
	Enamel rods in the cervical area directed occlusally
	Broad and flat contacts
	Color is usually lighter

Crowns of Primary Teeth

	Prominent mesio-buccal cervical bulge seen in primary molars
	Incisors have no developmental grooves or mammelons

Primary Crown Anatomy

	Mandibular Incisors- central is symmetrically flat when viewed from buccal, lateral has a more rounded DI angle
	Maxillary Incisors- central is only tooth that has a greater width than height
	Maxillary 1st Molar- unique look, 3 cusps
	Mandibular 1st Molar- 4 cusps, transverse ridge dividing occlusal surface

Primary Crown Anatomy

	Canines- maxillary is long and sharp, mandibular has similar shape but smaller
	Maxillary 2nd Molar - resembles permanent maxillary first molar but smaller
	Mandibular 2nd Molar- resembles permanent mandibular first molar but smaller

Pulps of Primary Teeth

	Relatively larger
	Pulp horns are closer to the outer surface
	Great variation in size and location
	Mesial pulp horn is higher
	Pulp chamber shallow
	Form of the pulp follows the external anatomy
	Usually a pulp horn under each cusp

Pulpal Anatomy

Roots of Primary Teeth

	Roots of anterior teeth are narrower mesio-distally
	Posterior teeth have longer and more slender roots in relation to crown size
	Molar roots flare more as they approach the apex
	Apical foramina may be larger and accessory canals often larger and more numerous

Implications of Primary tooth morphology

	The progress of caries is much faster in the primary dentition, so incipient lesions should be restored sooner than later!
			Thinner enamel and dentin
			Mesial pulp horn higher

Procedures in Primary Teeth

	Restorative Dentistry
			Enamel is thinner, therefore modifications are necessary in the cavity prep
			Broad contacts need to be restored
			Beware of the mesio-buccal pulp horn
			May need to do SSC if both proximal surfaces involved
			Preserve the buccal cervical ridge to obtain mechanical retention for SSC

Procedures in Primary Teeth

	Surgical Procedures
			Conical anterior roots facilitate easy removal
			Flared roots of the molars - use caution as premolar buds are located between the roots
	Pulp Therapy
			Pulpotomy- beware of perforations
			Pulpectomy
				Difficult on molars due to tortuous and irregular pulp canals
				Beware of tooth buds

Summary

	Primary teeth have
		Thinner enamel and dentin layers
		Pulp horns closer to the outer surface
		Mesial pulp horn much higher
		Relatively larger pulps
		Enamel rods direct slightly occlusally in the cervical area
		Cervical area is constricted significantly
		Roots flare as they approach the apex
		More tortuous and irregular pulp canals