This ppt describes about how teeth erupts into oral cavity from within jaws and various theories to explain the mechanism followed by various factors affecting eruption

2. ERUPTION OF TEETH

3. DEFINITION
The word ‘eruption’ refers to the cutting of the tooth
through the gums
(From Latin ‘Erumpere’, meaning “to breakout”)
“ TOOTH ERUPTION is the process whereby a tooth
moves axially from its developmental position within the
alveolar crypt of the jaw into its functional position within
the oral cavity”.
- According to Orban’s

4. STAGES IN THE ERUPTION OF THE TEETH
(Noyes and Schour)
Stage 1: Preparatory stage(opening of the bone crypt)
Stage 2: Migration of teeth towards oral epithelium
Stage 3: Emergence of crown tip into the oral cavity (beginning of
clinical eruption)
Stage 4: First occlusal contact
Stage 5: Full occlusal contact
Stage 6: Continues eruption

5. NOLLA’S STAGES OF TOOTH
DEVELOPMENT (1960)

6. Physiologic tooth movement
Pre-eruptive phase
Eruptive phase
(Pre-functional eruptive phase)
Post-eruptive phase
(Functional phase)
Three distinct phases

7. Pre-Eruptive Phase
- Deciduous and permanent teeth
- Movements of tooth - from the time of their early initiation
and formation to the time of crown completion.
- Concentric Growth
- Deciduous tooth differentiates
- Bony remodelling of crypt wall

10. • Permanent molars have
no predecessors
• Maxillary molar- slanting
distally.
• Mandibular molars-
slanting mesially.

11. ERUPTIVE PHASE
• Starts with the initiation of root formation and ends when
the teeth reach occlusal contact
• Four major events occur during this phase:
1. Root formation
2. Moves through the bone of
the crypt and connective
tissue of oral mucosa

12. 3.Tip of crown enters the oral
cavity by degenerating the
membrane and breaking through
the epithelium.
4. Intraoral movement occurs
until the crown contacts the
opposing teeth.

13. Post Eruptive Phase
• Takes place after the teeth are
functioning and continues as
long as the teeth are present in
the mouth
• Accomadate the growth of the jaws
• To compensate for continued occlusal
wear
• To accomadate interproximal wear
- Ant comp of occlusal force.
- Transeptal ligament contraction.

14. • Preeruptive phase
• Eruptive phase
• Posteruptive phase
Histology of tooth eruption

15. Eruptive phase
• Initial changes- alteration of connective
tissue of the dental follicle
• Zone of decreased and degenreated
connective tissue fibers, cells, blood
vessels, and terminal nerves
• Altered tissue space overlying the tooth
becomes visibles as an inverted funnel
shaped area with the follicle fibers
directed toward the mucosa-
gubernacular cord. This guides the tooth
in its eruptive movements
• Osteoclasts
Changes in tissues overlying teeth

16. • As eruptive movements commences, collagen fibers
become prominent.
• 1st at cervical area of root and extend coronally to
alveolar process
• Myo-fibroblasts
• Alveolar bone remodelling continues.
Changes around the teeth

17. • In soft tissues and fundic bone.
• As the tooth erupts, space is provided for the root to
lengthen,
• Primarily due to the crown moving occlusally and
increase in the height of the alveolar bone.
• Changes in the fundic region are thus, believed to be
largely compensatory to the lengthening of the roots.
Changes in tissues underlying teeth

18. Post eruptive phase
• Alveolar process increase in height and roots continue to
grow.
• Alveolar bone density increases
• Principle fibers of PDL establishes into separate groups.
• Diameter of fiber bundle increases.

19. Theories Of Tooth Eruption
- Root formation theory
- Bone remodelling
theory
- Dental follicle theory
- Vascularity theory
- Foreign body theory
- Pulp constriction
theory
- Cushion hammock
ligament theory
- Periodontal ligament
contraction theory
- Tissue hydrostatic
pressure theory
- Cellular proliferation
theory
- Hormonal theory
-Pressure from
muscular action
- Resorption of the
alveolar crest
- Blood vessel thrust
theory

20. Root Elongation theory
• Simplest, most obvious mechanism
• Evidence against the theory:
- Rootless teeth erupt
- Some teeth erupt a greater distance more than the
length of their roots
- Teeth still erupt even following root completion
- surgical removal of tissues of root, teeth continue to erupt.
- In animal studies, if a continuously erupting tooth is pinned to bone,
root formation continues.

21. • Root formation is a consequence not a cause of the
eruption process
• Root formation, per se is not required for tooth eruption,
although root formation under certain circumstances ,
may accelerate tooth eruption.

22. Bone Remodelling Theory
• Tooth moves by selective deposition and resorption of
bone.
• Marks and Cahill – When developing premolar is removed without
disturbing the dental follicle, an eruptive pathway is formed overlying
the enucleated tooth.
• If dental follicle is removed, no eruptive pathway.
• If replaced by metal or silicon replica- eruptive pathway.
• Establishes- Programmed bony remodelling
The role of the dental follicle.

23. Dental Follicle Theory
• Marks and Cahill (1980, 1984) demonstrated the role of
the dental follicle in tooth eruption with studies on dogs.
• Pattern of cellular activity - REE and the follicles.
• Intercellular signals.
• The REE also releases proteases.

24. Periodontal Ligament Traction
• Contractile element within the periodontal ligament,
collagen constriction and constriction due to fibroblasts
are responsible.
• Actual force required to move the tooth is linked to the
contractility of fibroblasts.
• Models:

25. Hydrostatic Pressure Theory
• Increase in hydrostatic pressure in the area around the
developing tooth creates the eruptive force.
• The hydrostatic theory was investigated by Hassel and
McMinn (1972) who demonstrated that the tissue
pressure apically was greater than occlusally
theoretically generating an eruptive force.
• No association was found between the rate of eruption
and the pressure gradient.

26. Hormonal Theory
• Sir Arthur keith- hormones of thyroids and pituitary
glands might govern the eruption of the teeth
• Doesn't explain the mechanism
• A study by Leache et al (1988), concluded that children
with delayed growth due to growth hormone deficiency
or low genetically determined height had delayed tooth
eruption. However those with delayed growth for other
reasons show normal dental development.

27. Pressure from muscular action
• Berten - Actions of muscle of cheeks and lips upon
alveolar peocess might serve to squeeze the crown of
the tooth into oral cavity.
• Fails to explain in cases of unilateral paralysis

28. Blood vessel thrust theory
• Eruption involves the blood supply to the tooth. The
blood generates the force by hydrodynamic and
hydrostatic force within the blood vessels.

29. Pulp constriction theory
• Growth of the root dentine and the subsequent
constriction of the pulp may cause sufficient pressure to
move the tooth occlusally.
• Neglected

30. Foreign body theory
• Gottlieb’s- Calcified body such as a tooth tends to be
exfoliated by the tissues just as it does to any foreign
body.

31. Resorption of alveolar crest
• Resorption of alveolar crest would serve to expose the
crown of the tooth out into the oral cavity.
• Not reliable since histological examination shows that
the alveolar crest is site where growth of the bone occurs
continuously.

32. Vascularity theory
• Constant (1896)- tissues which lie between the
developing tooth and its bony surrounding possess a
very rich vascular supply.
• Blood pressure exerted in this tissue is active
mechanical factor for eruption of teeth

33. ERUPTION RHYTHM
• Studies indicate that circadian rhythm exists during pre-
functional stage of eruption of human teeth.
• Teeth intrude transiently in conjunction with masticatory
activity and then erupt significantly overnight.
• Supine position versus an upright position.
• CLINICAL SIGNIFICANCE:
-Timing of eruption
-Daily rhythm in skeletal growth

34. SHEDDING OF PRIMARY TEETH
Definition:
“ The physiologic process resulting in the elimination of
the deciduous dentition is called shedding or
exfoliation”.
According to orban’s

35. Pattern of shedding
• Resorption of anterior teeth occurs on the lingual surface and these
teeth are shed with their pulp chamber intact.
• Resorption of primary molars occurs in interradicular dentine with
some resorption of the pulp chamber, coronal dentine and
sometimes enamel
• Right=left
• Mand> maxillary
• Girls> boys

36. Histology of shedding
• Odontoclasts: Large, multinucleated cells
Cytoplasm- vacuolated
Ruffled border
Derived from- TRAP- positive circulating monocytes
OPG and RANKL(RECEPTOR ACTIVATOR OF NUCLEAR FACTOR)

37. Mechanism of Resorption and
Shedding
Pressure: a key role because the odontoclasts
differentiates at predicted sites of pressure.
Force of mastication:

38. FACTOR INFLUENCING THE
ERUPTION OF TEETH
Genetic factor
Gender
Socioeconomic condition
Birth weight
Hormones & vitamins
Race
Local and systemic factors

39. - Ankylosis
- Dental caries and periapical infection
- Early loss of primary teeth
- Remnants of deciduous tooth
- Retained deciduous tooth
- Submerged deciduous teeth
- Congenital absence of teeth
- Tumor
- Cyst
- Abnormal habit exerting muscular
forces
Local factors

40. Teething and teething difficulties
• According to Macknin et al the teething period was defined as the 8-
day period, beginning 4 days before a tooth emergence and
extending 3 days after the event.
• Over half of babies have one or more problems during teething.
• Increased salivation
• In the past, a variety of physical disturbances such as croup,
diarrhea, fever, convulsions, primary herpetic gingivo-stomatitis, and
even death have been incorrectly attributed to eruption.

41. Clinical features of teething
Local signs
Hyperemia or Swelling of the mucosa
overlying the erupting tooth.
Patches of erythema on the cheeks
Flushed cheeks Systemic signs
General irritability and crying
Loss of appetitite
Sleeplessness restlessness
Increased salivation and drooling
Meningitis
Increased thirst
Circumoral rash
cough

42. Management
• Preventive measures:
Child’s oral and General body hygiene
Vitamins, Proteins, Minerals.
• General measures:
Rusks, Toasted bread, Hard fruits, Pacifiers,
Teething necklaces.
• Medical management:
Glycerin, Lignocaine Hydrochloride, Benzyl
Alcohol, Acetylsalicylic acid tablets, Hypnotic,
Homeopathy( chamomilla)
• Surgical treatment:

43. Disturbances In Eruption Of Teeth

44. Neonatal
teeth
Natal
teeth

45. NATAL AND NEONATAL TEETH
• Prevalence- 1 in 700 to 30,000 births
- natal > neonatal(3:1)
- females> males
• COGENITAL TEETH, FETAL TEETH OR DENTITION PRAECOX
• Bodenhoff’s study- 85% mandibular incisors,11%maxillary incisors,
3% mandibular canine and molars, 1% maxillary canine or molars
• Etiology: Hypovitaminosis, Harmonal stimulation, Trauma, Febrile
states , Syphilis ( cause n effect relation not established)
• Current concept: attributed to superficial position of the developing
tooth germ.

46. • The presence of such teeth may be a localized
manifestation of Environmental cause or an underlying
syndrome.

47. • Clinical features:
resemble normal primary teeth but they are poorly developed,
small,
conical,
yellowish,
white hypoplastic enamel, dentine and
with poor or total failure of development of roots
(hypermobile)

48. • Appearance of each natal tooth can be classified in 1 of
the following categories,
category1- A shell like crown structure loosely attached
to the alveolus by a rim of oral mucosa; no root.
category 2- A solid crown loosely attached to the
alveolus by oral mucosa; little or no root.
category 3- The incisal edge of the crown just erupted
through the oral mucosa.
category 4- A mucosal swelling with the tooth unerupted
but palpable.

49. Management
• Radiographs - Amount of root development.
- Relationship of prematurely erupted
tooth to its adjacent teeth.
• King and Lee- Inflamed gingival tissue around teeth- chlorhexidine
gluconate gel 3 times a day
• Sharp incisal edge- selective grinding
• Hypermobile- extraction- careful curettage, prophylactic administration of
vitamin k(0.5-1.0mg) was administered intramuscularly as a part of
immediate medical care to prevent hemorrhage. (J Oral Maxillofac Pathol. 2009 Jan-Jun;
13(1): 41–46. Natal teeth: Case report and review of literature Roopa S Rao and Sudha V Mathad)
• Preferable approach: leave the tooth in place, explain the parents the
desirability of maintaining this tooth in mouth.

50. Complications
• 1857 cardarelli- traumatic ulceration on ventral surface of
the tongue, frenulum or lip
• 1881 and 1890 riga and fede (Riga Fede disease).
• NEONATAL SUBLINGUAL TRAUMATIC ULCERATION

51. ERUPTION HEMATOMA/
ERUPTION CYST
• Mostly in primary second molars, Permanent 1st molar
• Result of trauma to soft tissues during function.
• Self limited
• Surgical uncovering

52. ERUPTION SEQUESTRUM
• Occasionally occurs at the time of eruption of 1st permanent molars.
• Starkey et al. (1963) described sequestra as a tiny spicule of non
viable bone overlying the crown of erupting molar just before or
immediately after emergence of the tips of the cusps through oral
mucosa.
• Watkins(1984)-composed of dentine and cementum
• Little or no significance

53. ECTOPIC ERUPTION
• Ectopic eruption is
defined as the abnormal
eruption of a permanent
tooth out of position and
causing the resorption of
a primary tooth in an
abnormal fashion.
• Arch length inadequacy
or variety of local factors
• Management
• (66%) correct
spontaneously
observation period of 2-3
month intervals

54. Ankylosis
• It is the aberration of tooth eruption in which continuity of
the periodontal ligament has been compromised and the
tooth is fused to the underlying bone.
• C/f:
• Common- mandibular primary molars.
anterior primary tooth- due to trauma

55. • Etiology: remains unknown
Extrinsic factors-
Local mechanical trauma,
Disturbed local metabolism,
Localized infection,
Chemical or thermal irritation
Tooth reimplantation.
Intrinsic factors;
Genetic or congenital gap in PDL
(Via WF1964 J Am Dent Assos :submerged deciduous molars: familial tendencies)

56. • Complications
• Treatment

57. Systemic conditions affecting the eruption of
teeth
- Hereditary gingival fibromatosis
- Trisomy 21 Syndrome
- Cleidocranial dysplasia
- Hypothyroidism
- Hypopitutarism
- Achondroplastic dwarfism
- Hyperthyroidism
- Hyperpituitarism
- Turner’s syndrome