Eruption and Shedding of tooth and its development to functional

Tooth eruption histology

1. Tooth Eruption and Shedding 1

2. Contents Introduction of eruption Phases of eruption Theories of eruption Mechanism of resorption and shedding Chronology of human dentition Teething and teething problems Management of teething problems Conclusion References 2

3. Eruption ERUPTION IS DEFINED AS AXIAL OR OCCLUSAL MOVEMENT OF THE TOOTHFROM ITS DEVELOPMENTAL POSITION WITHIN THE JAW TO ITS FUNCTIONAL POSITION IN THE OCCLUSAL PLANE. It is catagorized into three phases Phase 1 : The pre-eruptive phase Phase 2 : The eruptive phase Phase 3 : The post-eruptive phase 3

4. 1. Pre-Eruptive phase 4 Preparatory phase - Movement of developing tooth germs within alveolar processes prior to root formation Bodily movement Eccentric growth

5. 2. Eruptive phase 5 Noyes and Schour ; Stage 1 : Preparatory stage (Opening of bony crypts ) Stage 2 : Migration of tooth towards the oral epithelium Stage 3 : Emergence of crown tip into the oral cavity Stage 4 : First occlusal contact Stage 5 : Full occlusal contact Stage 6 : Continuous eruption

6. 6 The rate of tooth eruption depends on the type of movement 6

7. 3. Post- Eruptive phase movements made by the tooth after it has reached its functional position in the occlusal plane. 7 7

8. ACCOMMODATION FOR GROWTH - Mostly occurs between 14 and 18 years by formation of new bone at the alveolar crest and base of socket to keep pace with increasing height of jaws. COMPENSATION FOR OCCLUSAL WEAR - Compensation primarily occurs by continuous deposition of cementum around the apex of the tooth. However, this deposition occurs only after tooth moves. ACCOMMODATION FOR INTERPROXIMAL WEAR - Compensated by mesial or approximal drift. 8

9. Theories of Tooth eruption Root elongation theory Pulpal constriction theory Growth of periodontal tissues Pressure from muscular action Resorption of alveolar crest Hormonal theory Foreign body theory Cellular proliferation theory Vascularity theory Blood vessel thrust theory Periodontal ligament contraction theory Dental follicle theory Bone remodelling theory 9

10. 1. Root elongation theory Simplest and most obvious mechanism 10 Growth and elongation of roots Teeth pushed into the oral cavity Evidence against this theory; -Rootless teeth -submerged teeth

11. 2. Pulpal constriction theory 11 Growth of root dentin and constriction of pulp Tooth moves occlusally pressure Evidence against this theory; - Pulpless teeth - Permanent premolar jump into occlusion after premature extraction of decidious molar

12. 3. Growth of periodontal tissue 12 -Teeth is pulled by surrounding connective tissue -Alveolar bone growth Evidence against this theory; - Histologically ; Periodontal fibers are being pulled by tooth and not vice versa - Radiographically / Histologically ; Bone doesn’t actually touch the tooth

13. 4. Pressure from muscular action 13 Musculature of cheek and lips upon alveolar process Squeeze the crown of tooth out in oral cavity Evidence against this theory; Teeth even erupts in cases of unilateral facial paralysis

14. 5. Resorption of alveolar crest 14 Resorption of alveolar crest Expose the crown of the tooth in oral cavity Evidence against this theory; - Histologically ; alveolar crest is the site of most rapid and continuous growth of bone

15. 6. Hormonal theory 15 Hormones secreted by thyroid and pituitary gland Govern eruption of teeth Evidence against this theory; - Doesn’t explain the mechanism of teeth eruption

16. 7. Foreignbody theory 16 Calcified body such as tooth tends to be exfoliated by tissues just as does any foreign body

17. 8. Cellular proliferation theory 17 Cellular proliferation of pulpal and surrounding tissues Increased osmotic pressure and forces Eruption of teeth

18. 9. Vascularity theory 18 Rich vascular supply between teeth and its bony surroundings Increased pressured by vessels Eruption of teeth - Hyperemia; even submerged teeth erupts - Hyperemia in periodontitis - supraeruption of teeth

19. 10. Blood vessel thrust theory 19 Blood supply to the teeth Hydrodynamic and hydrostatic forces within blood vessels Eruption of the teeth

20. 11. Periodontal ligament contraction theory 20 Shrinking and crosslinking of fibroblast within periodontal liagament Traction forces like locomotion Eruption of teeth

21. 12. Dental follicle theory 21 Reduced enamel epithelium cascade of intercellular signals recruits osteoclast to the follicle bone remodelling erution of teeth

22. 13. Bone remodelling theory 22 Bone remodeling The growth pattern of the maxilla and the mandible moves teeth by selective deposition and resorption of bone. Major proof is when a tooth is removed without disturbing its follicle tooth germ, an eruptive pathway still forms within bone as osteoclasts widen the gubernacular canal. If the dental follicle is also removed no eruption path develops. It establishes absolute requirement for a dental follicle to achieve bony remodeling and tooth eruption.

23. 23 Shedding of Decidious teeth

24. 24 Shedding of Decidious teeth shedding or exfoliation of deciduous teeth is a term given to describe the physiologic process that ultimately leads to replacement of the deciduous teeth by their corresponding permanent successors  resorption with permanent sucessor resorption with out permanent sucessor 24

25. Resorption with permanent sucessor 25 Anterior teeth resorption with permanent sucessor - Resorption of lingual surface of apical third of primary tooth root. - Resorption of labial surface. - Resorption proceeds horizontally in incisal direction until primary tooth sheds & permanent tooth erupts.

26. Resorption with permanent sucessor 26 Posterior teeth resorption with permanent sucessor -The growing crown of the permanent posterior teeth are situated between the roots between primary molars - Initiation is by resorption of inter- radicular bone followed by resorption of the adjacent surfaces of the root of primary tooth

27. Resorption without permanent sucessor The root is protected from resorption by presence of narrow PDL cell layers which are composed of: - Collagen fibers - Fibroblasts - Cementoblasts Degradation of PDL precede root resorption & removal of collagen fibers of PDL is considered main step in initiation of this process. As face grows & muscles of mastication enlarge, forces that are applied on the deciduous teeth become heavier than periodontal ligament can withstand primary tooth . 27

28. Problems associated with shedding 28 Remnant of decidious dentition; -parts of the root of decidious teeth embeded in jaw for considerable time -frequently found in association with permanent premolars because the roots of lower 2 nd decidious molars are strongly curved or divergent Retained decidious teeth; Absence of permanet sucessor impacted permanent sucessor

29. Nolla’s stage of teeth eruption,1952 29

30. Chronology of human dentition 30 Sequence of primary teeth eruption Maxillary arch ; A-B-D-C-E Mandibular arch ; A-B-D-C-E Sequence of permanent teeth eruption Maxillary arch ; 6-1-2-4-5-3-7 Mandibular arch; 6-1-2-3-4-5-7

31. Chronology of human dentition 31 7 ½ 9 18 14 24 20 12 16 7 6

32. Chronology of human dentition 32

33. Importance of primary teeth -Chewing on well-formed teeth helps the jaw bones to grow and develop properly. -provide proper space for the eruption of permanent teeth. -are necessary for proper chewing of food, and normal digestive processes. -are also necessary for learning speech sounds and proper language development. -Healthy baby teeth are also important for a child's self-esteem and well being 33

34. Problems associated with primary teeth eruption Teething Eruption cyst Eruption sequestration Ectopic eruption Non-eruption Natal and neonatal teeth 34

35. 35 Signs and symptoms of teething; -Pain -Inflammation of mucous membrane -General irritability/malaise -Disturbed sleep/wakefulness -Facial flushing/ circumoral rash -Drooling/ sialorrhea -Gum rubbing/biting/sucking -Constipation/diarrhea -Loss of appetite -Ear rubbing Management Non pharmacological -Teething rings (chilled) -Hard sugar-free teething rusks -cucumber (peeled) - Frozen items like bananas, vegetables Pacifiers Rub gums with clean finger, wet guaze Reassurance Pharmacological - Analgesic/antipyretics -Topical anesthetic agents -Alternative holistic medicine Teething .. Process of eruption of first teeth into the oral cavity

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37. Steward’s approch to teething 1 st approach – give the child freezed teething rings to bite - greatest relief If pain is troublesome, give appropriate dose of sugar free paracetamol elixir every 4-6 hourly Additional analgesia – lignocaine based teething gels 37 Paracetamol 3-12 months = 60-120 mg 1-5 years = 120-150 mg Lignocaine 7.5mm of gel should be placed on a clean finger or cotton bud, and rubbed into painful areas.

38. Teething problems 38 -Eruption hematoma -Eruption sequestratrum -Ectopic eruption -Natal and neonatal teeth -Non eruption teeth

39. Eruption hematoma (eruption cyst) - blood filled cyst -bluish purple, elevated area of tissue -occasionally develops few weeks before eruption of primary/permanent dentition -results due to trauma to soft tissue during function -subsides after eruption of teeth -common area; primary 2 nd molar or permanent 1 st molar region 39

40. Eruption hematoma (eruption cyst) 40

41. Eruption sequestrum - ocasionally seen in the children at the time of eruption of 1 st permanent molar -composed of cementum like material formed within the dental follicle -Hard tissue fragments is generally overlying the central fossa of associated embedded tooth and contoured of soft tissue -as tooth erupts, the cusp emerge the fragment sequestrates -usually little or no clinical significance 41

42. Ectopic eruption - due to arch length inadequacy or a variety of local factors 42

43. Natal and neonatal teeth -Teeth if present at birth – natal teeth -Teeth if present within thirty days of life – neonatal teeth [ Massler and Savara , 1950] 43 Clinical appearance -most commonly affected -lower primary central incisor - normal teeth to poorly developed, small, conical, yellowish, white hypoplastic enamel or dentin and underdeveloped root

44. Natal and neonatal teeth 44 Etiology Hypovitaminosis - Hormonal stimulation Trauma - Febrile states -Syphilis [current concept – superficial position of the developing tooth germ predisposes tooth to erupt early]

45. Natal and neonatal teeth 45

46. Natal and neonatal teeth 46 Management; - Radiograph : amount of root development - Topical chlorhexidine application : inflammed gingiva around teeth - Selective grinding of teeth : sharp incisal edge - Removal of hypermobile teeth : avoid risk of aspiration - Curettage of socket after extraction : remove any odontogenic cellular remnants Complications; -Traumatic ulceration on the ventral surface of the tongue, frenum or lips, ulceration on the sublingual area. -Riga and Fede 1881, 1890 decribed “ Riga – Fede disease ”

47. Non-eruption of teeth 47 Noneruption teeth; In case of non eruption of teeth beyond their common schedule Advisable to give a minor incision to facilitated their eruption if they are no associated with impaction or pathologies Local causes: -mucosal barrier -supernumerary teeth -injuries to primary teeth Genetic causes : -Gardner syndrome - Cleidocranial dysplasia Endocrinal causes : -Hypothyroidism - Hypoparathyroidism - Hypopituitarism

48. FACTS Why primary teeth are called milk teeth? - Milk teeth are called so due to their white color which resembles the color of milk. The milk teeth are whiter than the permanent teeth which replace them. The refractive index of milk teeth  is 1.338, similar to that of milk and hence they are called so. 48

49. FACTS Why there is no bleeding on eruption of teeth? -Reduced enamel epithelium unites with the oral epithelium. - REE has no blood supply , As the cells of the reduced enamel epithelium degenerate, the tooth is revealed The crown breaks the double layer epithelium overlying it and enters the oral cavity 49

50. FACTS Accelerating factors - Hyperthyroidism - Hperparathyroidism - Hyperpituitarism Decelerating factors -Hypothyroidism - Hypoparathyroidsm - Hypopituitarism 50

51. Conclusion For the clinicians to treat dental problems knowledge of proper eruption time is very important . A variety of developmental defects that are evident after eruption of the primary and permanent teeth can be related to local and systemic factors. 51

52. References ; Textbook of pediatric dentistry- 3 rd edition- Nikhil marwah Textbook of pedodontics – 2 nd edition – Sobha Tandon http://www.healthunit.org/dental/children_oral/primary_teeth_facts.htm http://www.32teethonline.com/pediatric-dentistry-teeth-dental%201.htm https://www.google.com/search.wikepedia http://www.hindawi.com/journals/scientifica/2014/341905/ http://phpa.dhmh.maryland.gov/oralhealth/docs1/fact_sheets/Infant_and_Toddler_OH-teething.pdf https://dentalpguploads.wordpress.com/2013/05/06/nollas-stage-of-tooth-eruptionaiims-12/ 52

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