Primary mandibular canine

description of deciduous mandibular canine.

1. GOOD AFTERNOON

2. DECIDUOUS MANDIBULAR CANINE Dr ANASWARA S 1 ST year PG DEPARTMENT OF PEDIATRICS AND PREVENTIVE DENTISTRY

3. CONTENTS INTRODUCTION CHRONOLOGY DIMENSIONS INDIVIDUAL ASPECTS a) LABIAL ASPECT b) LINGUAL ASPECT c) MESIAL AND DISTAL ASPECT d) INCISAL ASPECT ANATOMY OF PULP MORPHOLOGICAL ANAMOLIES CLINICAL IMPLICATION SUMMARY

4. INTRODUCTION The mandibular canines are two in number— right and left. situated distal to the mandibular lateral incisors in the right and left quadrants of the mandibular arch. The deciduous mandibular canine is smaller than the deciduous maxillary canine in all dimensions. The crown is asymmetrical and slender than the deciduous maxillary canine.

5. CHRONOLOGY 1 st evidence of calcification : 17 (16-18) weeks in utero Crown completion : 9 months Eruption : 20 (17-23) months Root completion : 3 ¼ years Shedding : 9 years NOMENCLATURE

6. DIMENSIONS Length in millimetres Over all length 17.5mm Length of crown 6mm Length of root 11.5mm Mesiodistal diameter of crown 5mm Mesiodistal diameter of crown at cervix 3.7mm Labiolingual diameter of crown 4.8mm Labiolingual diameter of crown at cervix 4.0mm

7. LABIAL ASPECT CROWN Shape of the crown : pentagonal from labial and lingual aspect. Formed by the mesial outline, distal outline, mesial cusp ridge and distal cusp ridge. Outlines of the crown: Mesial outline : convex from the cervical line up to the mesial contact area and it is longer than the distal outline. Distal outline : convex but less rounded and shorter than the mesial aspect and it extends from the cervical line up to the distal contact area. Cervical outline : semicircular, with the convexity facing towards the root apex.

8. Incisal outline: long, well- developed, sharp, pointed cusp incisal aspect. It forms the mesial cusp ridge and distal cusp ridge which meet at an acute angle. The mesial cusp ridge is shorter than the distal cusp ridge and is convex, with a steep inclination from the cusp tip. The distal cusp ridge is long and is either flat or concave and not as steep as the mesial cusp ridge. As a result of this variation in the length of the cusp ridges, the canine cusp is mesially placed to the long axis of the tooth. Labial surface of the crown : The labial surface exhibits an indistinct labial ridge called the canine ridge, which extends from the cervical line up to the cusp tip and is mesially placed. On either side of the canine ridge, developmental depressions are seen demarcating the facial developmental lobes.

9. In the cervical third of the labial surface, the labial cervical ridge is seen but it is not that prominent. Shape of the root : A single, long and slender root is present with a pointed apex. The root length is twice the length of the crown. There is a slight distal inclination of the root at the apical third. Outlines of the root: The mesial and distal outlines of the root taper evenly from the cervical line up to the apex. Labial surface of the root: The labial surface is flat and smooth without any developmental depressions or grooves. Contact areas: Distal contact area is cervically placed than the mesial contact area.

10. LINGUAL ASPECT Shape of the crown : Angular or diamond shaped, formed by the mesial outline, distal outline, mesial cusp ridge and distal cusp ridge. The mesiodistal width of the crown in this aspect is comparatively less than that of the labial aspect because of the lingual convergence of the mesial and distal sides of the crown. Outlines of the crown: Mesial outline: convex from the cervical line up to the mesial contact area and is longer than the distal outline Distal outline: convex but more rounded and shorter than the mesial aspect and extends from the cervical line up to the distal contact area.

11. Cervical outline: Semicircular with the convexity facing towards the root apex. Incisal outline: A long, well-developed, sharp, pointed cusp is seen in the incisal aspect. It is formed by the mesial cusp ridge and the distal cusp ridge, which meet at an acute angle. The mesial cusp ridge is shorter than the distal cusp ridge and is convex with a steep inclination from the cusp tip. The distal cusp ridge is long and is either flat or concave and not as steep as the mesial cusp ridge As a result of the variation in the length of the cusp ridges, the canine cusp is mesially placed to the long axis of the tooth.

12. Lingual surface of the crown: The lingual surface is irregular and indistinct. The cingulum is not that well developed as the maxillary canine and it occupies the cervical third of the crown. The marginal ridges are also not well developed and the distal marginal ridge is shorter than the mesial marginal ridge. The indistinct lingual ridge is mesially placed and extends from the cusp tip to the cingulum and divides the lingual fossa into shallow mesial and distal lingual fossae Shape of the root: A single, long and slender root is present with a blunt apex. The root length is twice the length of the crown. There is a slight distal inclination of the root at the apical third.

13. Outlines of the root: The mesial and distal outlines of the root taper evenly from the cervical line up to the apex. Similar to the crown, the root also tapers towards the palatal surface making it narrow mesiodistally. Lingual surface of the root: The lingual surface is smooth with a ridge extending from the cervical line up to the apex. The lingual tapering of the mesial and distal surface of the root results in this ridge. The cross-section of the root is triangular, with the base formed by the labial surface, the apex formed by the lingual surface and the other two sides of the triangle formed by the mesial and distal sides.

14. MESIAL ASPECT Shape of the crown: W edge shaped or triangular, with t he base formed by the cervical line, the apex formed by the incisal ridge and the other two sides formed by the labial and lingual surfaces. The labiolingual width at the cervical third is less than that of the deciduous maxillary canine. The cusp tip is situated lingual to the root axis line. Outlines of the crown: Labial outline: From the cementoenamel junction or the cervix, the labial outline is convex in the cervical third and flat in the middle and incisal third up to the cusp tip . Lingual outline: S shaped. It is convex at the cingulum and concave at the mesial marginal ridge/fossa and again convex at the cusp region.

15. c) Cervical outline: semicircular, with the convexity facing towards the cusp. d) Incisal outline: A sharp pointed cusp is seen. Mesial surface of the crown: S mooth without any developmental depressions or grooves. Mesial contact area: S ituated in the middle of the middle third of the crown. Shape of the root: A single, cone-shaped root is present with a blunt apex . Outlines of the root: The root is wider labiolingually in the cervical and middle third and tapers in the incisal third, ending in a blunt apex. There is a slight lingual inclination of as much as 10° in the apical third of the root. Mesial surface of the root: smooth without any developmental depressions or grooves.

16. DISTAL ASPECT Shape of the crown: W edge shaped or triangular, with the base formed by the cervical line, the apex formed by the cusp and the other two sides formed by the labial and lingual surfaces. Outlines of the crown: a) Labial outline: From the cementoenamel junction or the cervix, the labial outline is convex and flat in the middle and incisal third up to the cusp tip. b) Lingual outline: S shaped. It is convex at the cingulum and concave at the distal marginal ridge/fossa and again convex at the cusp region. c) Cervical outline : semicircular, with the convexity facing towards the cusp, but the depth of curvature is less than in the mesial aspect.

17. d) Incisal outline : A sharp, pointed cusp is seen in the incisal aspect. Distal surface of the crown: smooth without any developmental depressions or grooves. Distal contact area: situated in the middle of the middle third of the crown. Shape of the root: A single, cone-shaped root is present with a blunt apex. Outlines of the root: The root is wider labiolingually in the cervical and middle third and tapers in the incisal third ending in a blunt apex. There is a slight lingual inclination of 10° in the apical third of the root. Distal surface of the root: S moothly convex with a prominent developmental depression in the middle and cervical third of the root.

18. INCISAL ASPECT Shape of the crown: Diamond-shaped from incisal view Labial outline: B road and smoothly convex mesiodistally and shows canine ridge in the center of the labial surface. (b) Lingual outline: Narrower than the labial outline because of the tapering of the lingual surface towards the cingulum. (c) Mesial and distal outlines: B road to have a good contact area with the adjacent teeth. Outlines of crown:

19. PULP MORPHOLOGY The pulp morphology conforms to the external morphology of the tooth, with no demarcation between the pulp chamber and pulp canal.

20. Natal and Neonatal Teeth According to Bodenhoff’s study of natal and neonatal teeth, 3 percent are mandibular canines and molars are affected . MORPHOLOGICAL ANOMALIES Accessory roots In the primary denti­tion this most commonly affects the molars, but the primary canines and maxillary incisors can also be affected. Accessory roots have been reported to occur in 1–9% of the primary dentition Traumatic ulceration Traumatic ulcers are frequently seen in the child in areas accessible to the teeth and biting, such as the cheek or lower lip in the area of the canine teeth or sharp lower incisor mamelons.

21. Primate spaces : Exist between the maxillary lateral incisors and the canines (present mesial to maxillary deciduous canines) and mandibular canines and 1st deciduous molars (present distal to mandibular deciduous canines). These spaces are also called as anthropoid or simian spaces as they were initially found in our ancestral simian species. CLINICAL IMPLICATION

22. CLINICAL IMPLICATION Canine Relationship • The relationship of the maxillary and mandibular deciduous canines is one of the most stable in primary dentition. Class I: The mandibular canine interdigitates in embrasure between the maxillary lateral incisor and canine Class II: The mandibular canine interdigitates distal to embrasure between the maxillary lateral incisor and Canine Class III: The mandibular canine interdigitates in any other relation

23. SUMMARY The form of the mandibular canine is similar to that of the maxillary canine, with a few exceptions. The crown is slightly shorter, and the root may be as much as 2 mm shorter than that of the maxillary canine. The mandibular canine is not as large labiolingually as its, maxillary counterpart. Characteristic features for identification : • The cervical ridges labially and lingually are not as pronounced as those found on the maxillary canine. • Distal cusp slope is longer than the mesial slope as compared to primary maxillary canines.

24. REFERENCE McDonald and Avery Dentistry for the Child and Adolescent , Jeffrey A. Dean Textbook of paediatric dentistry , Nikhil Marwah PAEDIATRIC DENTISTRY FIFTH EDITION , Richard Welbury , Monty S. Duggal ,Marie Thérèse Hosey Atlas of the Human Dentition, Charles J. Goodacre Textbook of Oral Anatomy, Histology, Physiology and Tooth Morphology, K. Rajkumar , R. Ramya Textbook of Dental Anatomy, Physiology and Occlusion, Rashmi G S ( Phulari )

25. GUIDED BY Dr Rani Ma’am Dr Deepthi Ma’am Dr Shipra Ma’am Dr Sharib Sir

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