Pulp and root morphology of primary teeth

Objectives Pulp morphology of each primary tooth Features of the Deciduous Pulp Number of canals of each primary tooth Practical application of Understanding tooth morphology

Pulp and root morphology of primary teeth Considerable individual variation exists in the size of the pulp chamber and pulp canal of the primary teeth. Immediately after the eruption of the teeth, the pulp chambers are large, and in general they follow the outline of the crown.

PULP CHAMBER The pulp chamber will decrease in size with an increase in age under the influence of function and of the abrasion of the occlusal and incisal surfaces.

it is suggested that the dentist examine critically the bite-wing radiographs of the child before undertaking operative procedures.

The root will begin to resorb as soon as the root length is completed The root will begin to resorb as soon as the root length is completed. The resorption causes the apical foramen to change continually, and canal length change. Simultaneously, secondary dentin is deposited within the root canal system.

The deposition produces variations and alterations in the number and size of the root canals, as well many small connecting branches between the facial and lingual aspects of the canals. Accessory canals, lateral canals, and apical ramifications of the pulp may be found in 10 to 20% of primary molars

Features of a Deciduous Pulp The pulp chamber of the deciduous tooth is larger than that of the permanent tooth in relation to the crown size. primary permanent

2. The pulp horns of the deciduous tooth (especially the mesial horns) are closer to the outer surface of the tooth than are those of the permanent tooth. primary permanent

3. The mandibular molar has larger pulp chambers than does the maxillary molar in the deciduous tooth. 4. The form of the pulp chamber of the deciduous tooth follows the surface of the crown. primary permanent

5. Usually there is a pulp horn under each cusp. 6 5. Usually there is a pulp horn under each cusp. 6. Thin and slender roots pulp canals. primary permanent

7. Accessory canals extend from floor of the pulpal chamber to the furcation or inter-radicular area. 8. Increased blood supply, due to which the deciduous pulp exhibits typical inflammatory response.

9. Responds by inflammatory process, resulting in increased internal resorption. 10. Reduced sensitivity to pain— due to less number of nerve fibers.

11. Poor localization of infection and inflammation. 12 11. Poor localization of infection and inflammation. 12. Multiple ramification, making complete debridement impossible.

13. root canal narrower mesio-distally, discourages gross enlargement of the canal.

14. The roots of the posterior deciduous tooth are longer and more slender in relation to crown size than are those of the permanent tooth.

15.The roots of the deciduous molar flare more as they approach the apex (which affords the necessary room for the development of the permanent tooth buds) than do the permanent molar roots.

Number of canals of each primary tooth

Root canals of primary maxillary incisors: One canal

mandibular central and lateral incisors The pulp has One canal 10 % of mandibular incisors showed two canals in its root.

Root canals of maxillary and mandibular canines: The primary canines have the simplest root canals system of all the primary teeth and offers least problems when being treated endodontically. One canal

Root Canals of Maxillary 1st Primary Molars Three to four canals are usually seen in maxillary 1st primary molars. The palatal root is often rounded; it is often longer than the facial roots. A bifurcation of the mesiofacial roots into two canals occurs in approximately 75 percent of maxillary 1st primary molars.

Root Canals of Mandibular 1st Primary Molars It resembles to the external root anatomy, but it may have 2 to 4 canals. Mesial root contains 2 canals in 75% of the cases, where as only 25% of the distal root contains more than one canal.

Root Canals of Maxillary Second Molars Three to five canals are usually It usually resembles the external root shape. Mesiofacial root normally contains two distinct canals (85 to 90%).

Root Canals of Mandibular 2nd Primary Molars IT may have 2 to 4 canals. Mesial root has 2 canals in 85% of while distal root contains more than 2 canals In 85%

Root canal length before resorption

PRACTICAL APPLICATION OF UNDERSTANDING TOOTH MORPHOLOGY

1. Tooth preparations Modifications in the cavity depth and extension is required due to reduced thickness of enamel and dentin. B. Width of the occlusal cavity should be very much narrow in compliance with the narrow occlusal table. .

C. The inter-proximal contacts of primary teeth are broad and flat compared to those of permanent teeth. Use of a good wedge at the cervical part of the proximal box is necessary during material insertion and condensation into the proximal box

D. It is difficult to obtain an adequate gingival seat while preparing a Class II cavity due to the cervical constriction present in deciduous teeth. Trying to prepare a gingival seat in a deep cavity may lead to encroachment into pulp chamber.

2. Preformed Stainless steel crown preparations The prominent mesiobuccal cervical ridge of mandibular and maxillary first molars must be accommodated in the preparation of stainless steel crowns, which may otherwise result in a ‘rocking’ crown.

B. The gingival contour of the cervical margin that varies from the buccal to lingual to proximal aspects should be replicated while fabricating the crown. The cervical border of the crown must flow parallel to the gingival contour. M

C. The cervical border of the crown must be placed below the cervical bulge of the tooth (0.5 mm)to obtain maximum retention.

3. Surgical procedures Conical roots of primary anterior teeth facilitate easy removal. Extraction of deciduous molar teeth must be made with great caution. The premolar tooth bud is located between the flared roots of primary molars, which may be avulsed during deciduous tooth extraction.

the number and curvature of the root canals 4. Pulp therapy Understanding of the anatomy of the pulp, the number and curvature of the root canals is important during pulp treatment procedures.