2. Eruption of teeth…… ……..indeed a very complex phenomenon

3. ERUPTION : LATIN WORD “ERUMPERE”- TO BREAK OUT or Cutting of the tooth through the gum.  It is defined as the movement of a tooth in an occlusal direction. EMERGENCE : Is defined as the perforation of the gum tissues and the appearance of the tooth in the oral cavity.

4. Primary teeth : the physiologic principles underlying eruption that are discussed in this section are not different for the primary teeth, despite the root resorption that eventually causes their loss.  Pre emergent eruption  Post emergent eruption

5.  FOLLICULAR PHASE : - Characterized by a very slow labial or buccal drift of the tooth follicle within the bone. - the amount of change in the position of the tooth follicle is extremely small, observable only with vital staining experiments - this follicle can be used as a natural marker in radiographic studies of growth  ERUPTIVE movements begin soon after 1/4 th of the root is formed. -This supports the idea that metabolic activity within the periodontal ligament is necessary for eruption.

6. Two processes are necessary for pre-emergent eruption: 1)There must be resorption of bone and primary tooth roots overlying the crown of the erupting tooth. 2)The eruption mechanism itself then must move the tooth in the direction where the path has been cleared. Although the two mechanisms normally operate in concert, in some circumstances they do not. It has been demonstrated experimentally in animals that the rate of bone resorption and the rate of tooth eruption are not controlled physiologically by the same mechanism

7. Failure of teeth to erupt because of a failure of bone resorption occurs in humans, for eg, in the syndrome of cleidocranial dysplasia In children with this condition, - Resorption of primary teeth and bone is deficient, - Heavy fibrous gingiva and multiple supernumerary teeth also impede normal eruption. - All of these serve to mechanically block the succedaneous teeth (those replacing primary teeth) from erupting. - If the interferences are removed, the teeth often erupt and can be brought into occlusion

8. cleidocranial dysplasia

9. In a rare but now well documented human syndrome called "primary failure of eruption," - Affected posterior teeth fail to erupt, presumably because of a defect in the eruption mechanism. - Bone resorption apparently proceeds normally, but the involved teeth simply do not follow the path that has been cleared. - They do not respond to orthodontic force and cannot be moved into position. - No associated systemic illness, no underlying endocrine dysfunction and no associated genetic abnormality

10. Primary failure of eruption

11. UNCLEAR! However from animal studies it is clear that the eruptive mechanism is localized within the periodontal ligament. Cross linking of the maturing collagen provides the eruptive force, since the eruptive movements begin when the root formation starts.

12. Other theories:  Alteration in the vascular pressure.  Contraction of the fibroblasts.  Alteration in the extracellular ground substance of the periodontal ligament.  Deposition of the bone beneath the erupting tooth. PRE EMERGENT ERUPTION REMAINS AN ENIGMA!

13. Normally, the overlying bone and primary teeth resorb, and the eruption mechanism then moves the tooth into the space created by the resorption. The signal for resorption is activated by the beginning of root formation, but a tooth that is still embedded in bone can continue to erupt after root formation is completed, so active formation of the root is not necessary for continued clearance of an eruption path or for movement of a tooth along it. Normally, the rate of eruption is such that the apical area remains at the same place while the crown moves occlusally, but if eruption is mechanically blocked, the proliferating apical area will move in the opposite direction, inducing resorption where it usually does not occur. This often causes a distortion of root form, which is called dilaceration

14. Mononuclear cells ( osteoclast precursors) must be recruited into the dental follicle prior to the onset of eruption. These cells, in turn, fuse to form osteoclasts that resorb alveolar bone, creating an eruption pathway for the tooth to exit its bony crypt

15. EMERGES 3/4 th of its root development is complete. EMERGES erupts rapidly approaches the occlusal level and is subjected to masticatory forces. this is called POST EMERGENT SPURT Now eruption slows or almost halts - this phase is called JUVENILE EQUILIBRIUM During the juvenile equilibrium, teeth that are in function erupt at a rate that parallels the rate of vertical growth of the mandibular ramus

16. As the mandible continues to grow, it moves away from the maxilla, creating a space into which the teeth erupt. Exactly how eruption is controlled so that it matches mandibular growth, however, is not known

17.  The collagen cross linking in the periodontal ligament is more prominent after the tooth comes in occlusal function, so shortening of collagen fibers as the mechanism seems more likely  Vascular effects

18.  A final phase in tooth eruption.Ending of the pubertal growth spurt  Adult teeth continue to grow at a slow rate.  Antagonist is lost, tooth erupts more rapidly.  Thus eruption mechanism is capable of producing tooth movement late in life.  Wear of teeth is compensated by additional eruption.

19.  After the tooth is in occlusion, the rate of eruption is controlled by forces opposing eruption not those promoting it.  FORCES from chewing  Soft tissue pressure from the lips, cheek or tongue contacting the teeth.  But if severe wear occurs then eruption may not compensate for the loss of tooth structure. Vertical dimension may decrease.

20.  Occurs only during a critical period 8PM to1AM.  CIRCADIAN RHYTHM : During the early morning hours and the day, the tooth stops erupting and often intrudes slightly.  Similar cycle of growth hormone release  Excessive eruption of posterior teeth is a characteristic of long face. Since teeth erupt primarily at night and early morning it is possible that wearing an appliance during this time would be helpful.

21. FACTORS INFLUENCING TOOTH ERUPTION

22. 1. Age :- 2. Genetics :- 3. Race:- eruption timing seems to be earlier in the American black and Indian population than in American whites of European origin 4. Sex :- Except for the 3 rd molar Females tend to calcify and erupt their permanent teeth about five month earlier than males. FACTORS INFLUENCING TOOTH ERUPTION

23. 6. Environment :- 1. Socio economic group 2.Climate 7. General Factors :- 1.Disease 2.Hormone 3.Metabolism 4.Vit- C deficiency 5. Height and Weight :- Taller and heavier have greater number of erupted teeth then shorter and lighter children

24. Local Factors :- 1.Pathology, trauma, ankylosis 2.Early Loss of Primary teeth 3.Delayed Loss of Primary teeth 4.Impaction / Crowding 5.Supernumerary teeth 6.Space Available 7.Degree of Root Formation 8.Growth Factor

25. ERUPTION DISORDERS OF

26. All these Conditions are Attributed to a superficial position of Forming tooth Germ These may be:- 1.Natal Teeth :-Present at the time of birth. 2.Neo Natal Teeth:-Erupts with in 30 days after birth. 3.Preerupted Teeth :-Appear in 2 nd or 3 rd Month after birth.

27. Natal teeth

28. Situations in which it occurs:- 1.Ankylosis / Submerged tooth

29. 2.Congenital Hypothyroidism 3.Juvenile acquired Hypothyroidism

30. 4.Cleidocranial Dysplasia

31. 5. Down syndrome

32. 6.Gingival Fibromatosis

33. 7. Amelogenesis Imperfecta

34. 8. EPIDERMOLYSIS BULLOSA

35. 9. Mucopolysaccaridosis

36. TEETHING

37. Teething is the process by which an infant's teeth sequentially appear by breaking through the gums TEETHING The process of teething is sometimes referred to as "cutting teeth".

38. TEETHING SIGNS: General irritability Disturbed sleep Loss of appetite Chewing of objects Bruises/swelling in gums:Some blood and bruising during teething is common in most infants and babies:Not all babies bleed from the mouth when teething, but in some cases, a pocket of blood in the gum just above the tooth ruptures. eruption isn't any more painful than usual. It just looks scary to parents! Excess salivation

39. Running nose Teething has not been shown to cause fever or diarrhea. A slight rise of temperature may occur when the teeth come through the gum, but this does not make a baby ill.

40. Historical management of teething. Remedies that have been prescribed for teething through the ages have included blistering, bleeding, placing leeches on the gums, and applying cautery to the back of the head! Lancing Systemic medicaments Opiates and poisons such as lead acetate, mercurials and bromide. many of these compounds are actually causative of the symptoms associated with teething! The teething relief method under constant debate is the age-old remedy of rubbing rum or whiskey on the baby's gums.

41. Current methods of the management of teething Non-pharmacological management  Teething rings  Hard, non-sweetened rusks made from flour and wheatgerm with no sugar or sweetener  Reassurance Pharmacological management  Topical agents  Systemic analgesics

42. ‘Alternative' holistic medicine acupressure, aromatherapy, and homeopathy

43. DIFFERENCES BETWEEN PRIMARY AND PERMANENT TEETH