Primary teeth are important for several reasons, including aiding in speech development, chewing and eating, and guiding the eruption of permanent teeth. Tooth eruption is a complex process involving bone resorption and formation, as well as root development over several years before teeth emerge into the mouth. The sequence and timing of primary and permanent tooth eruption follows a generally predictable pattern, though there can be variations in individuals. Factors like genetics and local issues can influence the eruption process and cause problems like delayed, premature, or ectopic eruption.

1. Importance of Primary Teeth
 Smiling & self-esteem
 Chewing and eating
 Speech development
 Aid proper jaw and face formation
 Guide permanent teeth into place

2. Tooth eruption
“It is a series of metabolic events in the
alveolar bone characterized by bone
resorption & formation on opposite sides of
dental follicle but tooth does not contribute
to this process”

3. Tooth eruption
 The interval between crown completion & beginning of eruption until
tooth is in full occlusion is 5 years for permanent.
 Associated stage of root formation not chronologic or skeletal age.
 ¾ of the root formed.
 Tooth reach occlusion before root completion
 Sex difference in root completion ( girls).

4. STEPS OF TOOTH ERUPTION
1.Pre-emergent eruption - Pre-eruptive phase
a) resorption of the bone & primary tooth
roots
b) the eruption mechanism
2. Post-emergent eruption - Eruptive phase

5. STEPS OF TOOTH ERUPTION
2. Post-emergent eruption - Eruptive phase
a) post-emergent spurt - Eruptive phase
(Pre-functional)
b) Juvenile occlusal equilibrium
Eruptive phase (Functional)
c)Adult occlusal equilibrium

6. Development of the Tooth
• Initiation (Bud Stage)
– Early as 6th week of embryonic life
– All primary teeth and permanent molars arise from
the dental lamina
– Permanent incisors, canines, and premolars arise
from the primary predecessor
– Failure of initiation results in congenitally missing
teeth
• Excessive budding results in supernumerary
teeth

7. Factors related to tooth eruption
 Elongation of the root.
 Force of vascular tissues around & beneath root.
 Growth of the alveolar bone.
 Growth of dentin.
 Growth & pull of the periodontal membrane.
 Hormonal influences
 Presence of dental follicle.
 Pressure from muscles action.
 Resorption of the alveolar crest.

9. CHRONOLOGY OF THE HUMAN DENTITION
PRIMARY DENTITION
A.Hard Tissue Formation
B. Approximate Amount of Enamel at Birth
C. Enamel Completed
D.Eruption
E.Sequence of Eruption (Varies considerably)
F.Roots Completed
G. Sequence and Time of Exfoliation

10. - Primary Root completion 12- 18 months post
eruption.
- Teeth erupt when the root is 2/3 complete.
- Most favorable eruption sequence for primary
teeth both Maxillary & Mandibular:
ABDCE
- Tooth germs form at 6-8 wks IU
- enamel forms 4-6 months
CHRONOLOGY OF THE HUMAN DENTITION
PRIMARY DENTITION

11. (Varies considerably)
1. Centrals: Mandibular then maxillary
2. Laterals: Mandibular then maxillary
3. 1st Molars: Mandibular then maxillary
4. Cuspids: Mandibular then maxillary
5. 2nd Molars: Mandibular then maxillary
Usually the mandibular teeth erupt first
Eruption Sequence of primary

12. Primary dentition
 Mandibular central: 6 mos
 Mandibular lateral: 7 mos
 Maxillary central: 7 ½ mos
 Maxillary lateral: 9 mos
 Mandibular 1st molar: 12 mos
 Maxillary 1st molar 14 mos
 Mandibular cuspid: 16 mos
 Maxillary cuspid: 18 mos
 Mandibular 2nd molar: 20 mos
 Maxillary 2nd molar: 24 mos
Eruption sequence

13. Sequence and Time of Exfoliation
1. Central 6-7 yrs.
2. Laterals 6-8 yrs.
3. 1st Molars and Mandibular Cuspids 9-11 yrs.
4. 2nd Molars and Maxillary Cuspids 10-12 yrs.
Between 1-1/2 and 3-1/2 years
Roots Completed

14. Root CompletedEruptionHard Tissue Formation
Begins
Tooth
Maxillary
10 yr7-8 yr3-4 moCentral Incisor
11 yr8-9 yr10-12 moLateral Incisor
13-15 yr11-12 yr4-5 moCuspid
12-13 yr10-11 yr1 ½ - 1 ¾ yrFirst Bicuspid
12-14 yr10-12 yr2 – 2 ¼ yrSecond bicuspid
9-10 yr6-7 yrat birthFirst molar
14-16 yr12-13 yr2 ½ - 3 yrSecond molar
Permanent Dentition

15. Mandibular
9 yr6-7 yr3-4 moCentral Incisor
10 yr7-8 yr3-4 moLateral Incisor
12-14 yr9-10 yr4-5 moCuspid
12-13 yr10-12 yr1 ¾ - 2 yrFirst Bicuspid
13-14 yr11-12 yr2 ¼ - 2 ½ yrSecond bicuspid
9-10 yr6-7 yrat birthFirst molar
14-15 yr11-13 yr2 ½ - 3 yrSecond molar
Permanent Dentition

16. - Max: 61245378
- Man: 61234578
- Emergence when 2/3 root present
-Root completion 3 years post eruption (2-3 yrs.)
Eruption sequence:
- mandibular incisors
- 1st permanent molars, upper incisors
- canine (mand)
- 1st premolar
- max canine
- 2nd premolar
Permanent Dentition Eruption Sequence:

17. - Mand 1st molar: 6/7 yrs
-Max 1st molar: 6/7 yrs
-Mand central: 6/7 yrs
-Mand lateral: 7/8 yrs
-Max central: 7/8 yrs
-Max lateral: 8/9 yrs
-Mand cuspid: 9/10 yrs
-Mand 1st bicuspid: 10/11 yrs
-Max 1st bicuspid: 10/11 yrs
-Max 2nd bicuspid: 10/12 yrs
-Mand 2nd bicuspid: 11/12 yrs
-Max cuspid: 11/12 yrs
-Mand 2nd molar: 11/13 yrs
-Max 2nd molar: 12/13 yrs
Permanent dentition sequence

18. Growth & Development of the Teeth
 At birth the primary teeth have already formed
 Permanent teeth are developing or beginning to mineralize

19. ERUPTION SEQUENCE & TIMING
 Age 6: 16,26,36,46,41,31
 Age 8: 42,32,11,12,21,22
 Age 11: 33,34,43,44,14,24,
 Age 12: 13,23,35,45,15,25

20. ERUPTION SEQUENCE & TIMING
 Man. Canine then 1st 7 2nd premolar
(adequate arch length, prevent tipping of incisors)
( lingual tipping of incisors overbite )
( abnormal lip & oral habit collapse of anterior)
( passive Lingual arch SM in premature canine loss)
 Man.2nd molar erupt before 2nd premolar
(mesial drifting 1st molar space of 2nd premolar)

21. ERUPTION SEQUENCE & TIMING
 Loss of Max. primary molar
(1st molar drift& tip mesially canine labially blocked)
 Eruption of 2nd Max. molar premolars
( loss of arch length)
 Delayed eruption of the canine
( effect on alignment of anterior teeth)

22. At dental age 6

23. At dental age 8

24. The Ugly Ducking Stage
 Changes in the axial inclination due to the eruption of the
maxillary anterior teeth
7 years 9 years 14 years

25. At dental age 9

26. At dental age 9
 Root maxillary canines & second premolars is just beginning,1/3
root of the mandibular canines & first premolars completed.
Maxillary lateral incisors in place for 1 year
& root incisors and first molars nearly
complete.

27. Dental age 11

28. Dental age 11
Simultaneous eruption of the mandibular canines, mandibular first
premolars, and maxillary first premolars

29. Dental age 12

30. Dental age 12
 Eruption of the remaining succedaneous teeth (maxillary canine,
maxillary & mandibular second premolars) and, typically a few months
alter, the maxillary & mandibular second molars.

31. Dental age 15

32. Dental age 15
 Roots of all permanent teeth except the third molars are complete,
and crown formation of third molars completed.

33. ERUPTION OF PERMANENT MOLARS
MESIAL STEP
MESIAL STEP ERUPT IN CUSP-
GROOVE RELATIONSHIP
6/6
6/6

34. ERUPTION OF PERMANENT
MOLARS
DISTAL STEP
DISTAL STEP ERUPT IN DISTAL
RELATIONSHIP
6/6
6/6

35. The Ideal Primary Occlusion
• Ovoid arches
• Good interdental or primary spacing
• Flush terminal plane or mesial step molars
• Neutro cuspids

36. Occlusion

37. Variations in eruption
 Epstein Pearls, Bohn Nodules
 Natal and Neonatal teeth.
 Teething: a natural phenomenon & systemic distress.
 Eruption Hematoma (Eruption Cyst).
 Ankylosed teeth.
 Congenital factors influence eruption: Down Syndrome, Cleidocaial
Dysplasia.
 Local factors influence eruption: infection, trauma.

38.  Premature eruption of preliminary teeth
 Tooth should be retained unless mobile
Natal teeth
Natal Teeth - born with teeth.
Neonatal - 30 days after birth
- don't remove. (unless very mobile and
worried about aspiration
• 85% of natal or neonatal Teeth are
mandibular incisor.
• (1) 11% Maxillary incisor
• (2) 3% Mandibular cuspids
• (3) 1% Maxillary cuspids/molar

39. Dental Lamina Cyst

40. Eruption Hematoma

41. Teething Process

42. • Irritability • Fever
• Drooling • Diarrhea
• Mouthing • Pain
• Sleep Disturbance • Rash
• Biting • Gum rubbing
• Ear Rubbing • Decreased Appetite

43. Early eruption
Missing tooth
Impaction - failure to erupt
e.g., from too little gap after premature loss of deciduous
tooth
Delayed eruption
Malocclusion
Tilting (can occur early from germ rotation)
Infra-occlusion (not high enough)
Retained root fragment
Excessive drift
ERUPTION: Problems

44. FACTORS INFLUENCE THE ERUPTION
Local
Systemic
Congenital
 Two rows of teeth
 Ectopic eruption
 Infected primary teeth
 Ankylosis
 Primary failure of eruption
 Hypothyroidism
 Down’s Syndrome
 Achondroplastic Dwarfism
 Cleidocranial Dysplasia

45. Delayed Exfoliation of primary teeth

46. Causes of delayed tooth exfoliation

47. Premature loss & eruption time of
successors
 Unilateral loss before 4-5 year delay eruption
 Loss after 5 year decrease the delay
 Loss at 8-9 year accelerate the eruption

48. ANKYLOSIS
Primary dentition
 First molars most common
 Typically require no treatment and exfoliate normally
 Involved second molar maybe indication of agenesis of
succedaneous tooth
 Treatment:
 Prevent space loss
o Build-up occlusion surface of involved tooth
o Extract tooth and place space maintainer

49. ANKYLOSIS
 Permanent dentition
 Difficult to treat ankylosed permanent teeth
 Create adequate space
 Attempt to break area of ankylosis with luxation
 Immediately apply orthodontic traction force (>50 G) or
 Surgically reposition tooth and hold in position orthodontically (pulp
endodontic therapy necessary)
 Ankylosed permanent teeth tend to re-ankylose.

50. Causes of delayed tooth eruption
1. Endocrine disorders
• Hypothyroidism
• Calcium/phosphorus metabolism problems
• Hypopituitarism
2. Genetic disorders and bone disorders
Ectodermal dysplasias
• Down syndrome
• Cleidocranial dysplasia
• Gaucher disease
• Osteoporosis
3. Local factors
• Tooth in path of erupting tooth,
insufficient space, impacted teeth
• Dental infection
• Radiation therapy

51. ECTOPIC ERUPTION/IMPACTIONS
 Primary dentition
Extremely rare in primary dentition
 Permanent dentition
Permanent molars
 1st > 2nd; maxillary > mandibular
 Incidence of 1st molar: - 2-3%
 Suggested etiologies include
 Small maxilla
 Posterioly positioned maxilla
 relative to cranial base

52. Etiologies of ectopic eruption
 Molar path of eruption
• Mesio-distal dimension
• A synchronization between tuberosity
• Growth and molar eruption
• Retarded calcification and eruption
• Genetic

53. Treatment of ectopic eruption
 Treatment
 Mild: observation ( 2/3 of ectopically erupting 1st molars
will self-correct)
 Moderate: brass ligature; spring; distalize 1st permanent
molar
 Severe: extract primary molar and distalize 1st permanent
molar

54. Ectopic eruption
Permanent mandibular incisor
 Common: typically erupt lingual to over- retained primary incisors
 Rationale for treatment: allow teeth to move into area of attached gingival
 Treatment: extract primary incisors; tongue pressure will typically push
incisors into place

55.  Prevalence 1-2%
 Reported incisor root resorption - 50%
 Diagnosis
 Palpation
 Radiographic
─ Poor prognosis indicators
─ Permanent canine crown mesial of midline of lateral incisor root
─ Palatal displacement of permanent canine as viewed on cephalometric
Ectopic eruption
Permanent maxillary canines