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Outline

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