ERUPTION

AGE OF ERUPTION

Deciduous Teeth

A B C D EMaxillary 7 ½

months9

months18

months14

months24

months

Mandibular 6months

7months

16months

12months

20months

Sequence of eruption:

1. Central incisor2. Lateral incisor3. First molar4. Canine5. Second molar

In general:

1. Lower teeth erupts first compared to the upper teeth.

2. Girls teeth erupts first compared to boys.

Exfoliation

– casting away or throwing off of the surface of the deciduous teeth following eruption.

Resorption

– the gradual degeneration of a part & the removal of such from the body.

Succedaneous teeth – permanent teeth that follows the guide tooth.

Assessional teeth – they are the 1st, 2nd and 3rd molars.

Permanent Teeth

CI LI C 1PM 2PM 1M 2M 3M

Maxillary 7-8y/o

8-9y/o

11-12y/o

10-11y/o

10-12y/o

6-7y/o

12-13y/o

17-21y/o

Mandibular 6-7y/o

7-8y/o

9-10y/o

10-12y/o

11-12y/o

6-7y/o

11-13y/o

17-21y/o

Stages of Tooth Development:

1. Initiation2. Bud stage3. Cap stage/Proliferation4. Bell stage

/Morphodifferentiation5. Apposition6. Calcification7. Eruption

Nolla’s Calcification of Teeth (Growth Stage)

0 - Absence of crypt1 - Presence of crypt2 - Initial calcification3 - 1/3 of crown completed4 - 2/3 of crown completed5 - Crown almost completed

6 - Crown completed7 - 1/3 of root completed8 - 2/3 of root completed9 - Root almost completed with open apex10 - Apical end of root completed

X-ray reading for in-between stages:

0.2 – if reading is slightly greater than the illustrated grade/stage but not as much as halfway between that stage and the next.

○ ( Stage 7 = Stage 7.2 ) more than two thirds of the root is completed.

0.5 – reading that lies between two grades/stages.

○ ( bet. Stage 7&8 = Stage 7.5 ) between 1/3 and 2/3 of root is completed

0.7 – added to the preceding grade/stage when reading is slightly less than the grade/stage indicated.

○ ( less than Stage 7 = Stage 6.7 ) when 1/3 of the root is almost completed.

* Maturation of teeth can be used as a criterion of dental age as well as the physiologic age of the patient.

PRE-DENTAL JAW RELATION

> established before the eruption of the deciduous teeth approximately

3-5 months intrauterine & 5-6 months after birth.

> Characteristics:

1. Presence of gum pads, absence of teeth, maxillary gum pad wider mesio-distally than the mandibular & maxillary gum pad positioned more anteriorly.

2. Coronoid process higher than the condylar process because it has not obtained its growth & development fully.

3. Gonion or angle of the mandible is obtuse. (Adult – acute)

4. Absence of alveolar process.

5. Sites of mandibular bone growth:a) condylar processb) body of the mandible

6. Presence of interocclusal space or gap – this is a space between the maxillary & mandibular gum pads.

7. Presence of 20 sets of deciduous developing tooth buds.

DECIDUOUS DENTITION

> established when the deciduous teeth are present in the oral cavity from 6 months - 5 years.

>Characteristics:

1. Presence of developmental spaces found between the deciduous teeth to accommodate permanent teeth.

2. Presence of primate or anthropod spaces from the mesial of the maxillary canine & distal of the mandibular canine.

3. There is an end to end molar relation or cusp to cusp contact between molars, because the mandible has not yet attained its maximum growth.

There is the production of terminal flush plane (straight plane observed among the deciduous molar due to its end to end relationship, as the mandible grows anteriorly & inferiorly, normal occlusion results due to attainment of mesial step).

MIXED DENTITION/TRANSITIONAL PERIOD

> starts with the change from temporary to permanent dentition which covers from 6-14 years of age.

> divided into three stages:

1. Early = 6-8 years2. Middle = 8-10 years3. Late = 10=14 years

> Characteristics:

1. Ugly duckling stage – results from the movement of erupting permanent maxillary incisors towards the distal or distal flaring.

(This occurs between 8-12 years.)

(Distal flaring – distal inclination of the erupting teeth hence, there is the presence of developmental spaces between teeth. When the permanent canine emerge, the incisors will go to their normal position & the distal flaring subsides.)

2. Overlapping of maxillary incisors over mandibular incisors.

3. Establishes a mesial step – conducive to normal occlusion, the end to end contact of molars disappear, the MB cusp of maxillary 1st molar comes in contact with the buccal groove of the mandibular 1st molar.

4. Incisors remain to be distally flaring due to the following reasons:

a) abnormal MD width of teethb) abnormal attachment of labial

frenumc) presence of supernumerary

teeth

PERMANENT DENTITION

>covers age 15 and above

> Characteristics:

1. Normal surface to surface contact – normal overlapping of the incisors.

2. Normal cusp to fossa contact.

3. Normal triangular ridge to embrasure contact.

4. Normal triangular ridge to groove contact.

> Factors affecting the establishment of normal occlusion:

1. Muscular pressure.2. TMJ relation.3. Proximal contact of the teeth in the

same dental arch.4. Axial inclination of the teeth in

relation to occlusal forces.

5. Harmony in size & shape of dento-alveolar arches.

6. Inherent forces of growth.7. Atmospheric pressure(pressure of the mouth=pressure in all of the airways)

8. Forces of inclined planes of teeth.9. Morphology of teeth.