MANAGEMENT OF THE DEVELOPING DENTITION

OUT LINE

1. NORMAL DENTAL DEVELOPMENT

2. ABNORMALITIES OF ERUPTION AND EXFOLIATION

3. MIXED DENTITION PROBLEMS

4. PLANNED EXTRACTION OF DECIDUOUS TEETH

5. WHAT TO REFER AND WHEN

1. NORMAL DENTAL DEVELOPMENT

CALCIFICATION AND ERUPTION TIMES

THE TRANSITION FROM PRIMARY TO MIXED DENTITION

DEVELOPMENT OF DENTAL ARCHES

1. NORMAL DENTAL DEVELOPMENT

CALCIFICATION AND ERUPTION TIMES

1. NORMAL DENTAL DEVELOPMENT

THE TRANSITION FROM PRIMARY TO MIXED DENTITION

2. ABNORMALITIES OF ERUPTION AND EXFOLIATION

SCREENING

NATAL TOOTH

ERUPTION CYST

FAILURE OF/DELAYED ERUPTION

3. MIXED DENTITION PROBLEMS

PREMATURE LOSS OF DECIDUOUS TEETH

RETAINED DECIDUOUS TEEH

INFRA-OCCLUDED (SUBMERGED) PRIMARY MOLARS

IMPACTED FIRST PERMANENT MOLARS

DILACERATION

SUPERNUMERARY TEETH

HABITS

FIRST PERMANENT MOLARS OF POOR LONG TERM PROGNOSIS

MEDIAN DIASTEMA

1.Premature loss of of deciduous teeth: incisors, canines and 1st primary molar and 2nd primary molars

(Balancing and compensating extraction), space maintenance (the best is the tooth it self to maintain the bone around it)

2.Retained deciduous: if the contralateral tooth is not erupted in period of 6 months we should be suspicious and x rays should be taken

3. Infra occluded primary molars: 1-9 %, resorption is not continuous process and period of repair, ankylosis happen if only repair happen

Its associated with ectopic eruption, palatal displacement of upper canines, congenitally missing premolars.

Extraction of submerged teeth in two case:

1- The danger of the tooth dis-appearing below gingival level

2- Root formation of permanent tooth is near completion

4. impacted 1st permmanent molar: 2-6 % Ectopic eruptionBrass separation wire in mild cases for 2 months

5. dilacerations: distortion or bend of root of upper central or lateral incisorsCauses:Developmental ( female ,central) or Trauma (erupt palatal , enamel and dentin deformities)

6-supernumery teeth2 % permanent and 1 % deciduousMorphology: supplemental, conical. Tuberculate, odontomePosition: mesiodense, distomolar = paramolarManagement and effect: failure of eruption, displacement, crowding, no effect

7- habitsIntensity frequency and types

8- 1st permanent molars of poor long term factor to be considered: - check the presence of all permanent teeth – if dentition is un-crowded extraction should be avoided ––lower 2nd molar has been developed in the bifurcation – extraction of lower 6 alone will resolve post crowding not anterior ––impaction of lower 3rd molar is less likely after extraction of 1st molar

9- median diastema

98% of 6 years old49% of 11 y7% of 12-18 ys

Causes: -physiological –small teeth in large jaws –missing teeth –midline supernumery tooth –proclination of upper front –prominent frenum when associated with high frenum: - blinching of incisive papilla –radigraphicaly there is notch in the crest –ant. teeth are crowded

Management:If less 3 mm, no intervention if more than 3 mm and lateral is erupted then fixed appl and be carful of the root not to cause resorption

4. PLANNED EXTRACTION OF DECIDUOUS TEETH

SERIAL EXTRACTION

-Solve sever crowding in class I occlusion, all teeth present

-Extraction of Cs then Ds then 1st premolar

-Shifting the crowding from anterior to posterior segment

INDICATIONS FOR EXTRACTION OF DECIDUOUS CANINES -Crowding upper arch, lat erupt palatal

and in class I ,this will result in crossbite

– crowding lower ant arch with buccal eruption of permanent incisor , ex is indicated

-In class III lower extraction –to improve the displacement of permanent canines

5. WHAT TO REFER AND WHEN

DECIDUOUS DENTITION:

- CLEFT LIP AND PALAT

- CARINOFACIAL ANOMILIES

MIXED DENTITION

-Delay eruption of permanent incisors

–ectopic canine

-impaction of failure to erupt 6s

– medically compromise patient

- 6s with poor prognosis

–pathology like cyst

- ant cross bite with perio problem – sever class II

–hypo-dontia

Eruption of the Primary Teeth

Natal tooth

Primate space

Physical Development in Late Childhood Late childhood: from age 5 or 6 to the onset of puberty.By age 7,

completed neural growth. The brain and the brain case are as large as they will ever be.

Lymphoid tissue throughout the body has proliferated beyond the usual adult levels, and large tonsils and adenoids are common..

Growth of the sex organs has hardly begun

general body growth is only modestly advanced

Eruption of the Permanent Teeth

Preemergent Eruption

Postemergent eruption

Preemergent eruption Eruptive movement begins soon after the root begins to form.

Two processes are necessary for preemergent 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

Bone resorbtion and primary root resorption.

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.

Eruption mechanism

Controlling factors:

collagen maturation

blood pressure or flow

forces derived from contraction of fibroblasts,

alterations in the extracellular ground substances periodontal ligament

Postemergent eruption

It is divided into 2 stages:

Once a tooth emerges into the mouth. it erupts rapidly until it approaches the occlusal level and is subjected to the forces of mastication ( post emergent spurt)

At that point. Its eruption slows and then as it reaches the occlusal level of other teeth and is in complete function ( juvenile occlusal equilibrium)

Controlling factors: The rate of eruption controlled by the forces

opposing eruption, not those promoting it .Chewing Soft tissue pressure from lips, cheeks, or tongue contacting the teeth.

Adult Occlusal Equilibrium:

During adult life, teeth continue to erupt at an extremely slow rate. If its antagonist is lost at any age a tooth can again erupt more rapidly demonstrating that the eruption mechanism remains active and capable of producing significant tooth movement even late in life.

Eruption Sequence and Timing

Dental age is determined from three characteristics:

1. Which tooth have erupted

2. Amount of resorption of the root of the primary teeth

3. Amount of development of the permanent teeth.

Dental age 6

Dental age 7

The maxillary central incisors and the mandibular lateral incisors erupt.

root formation of the maxillary lateral incisor is well advanced, but it is still about 1 year from eruption.

the canines and premolars are still in the stage of crown completion or just at the beginning of root formation.

Dental age 8

Dental age 9

Dental age 10

Approximately one half of the roots of mandibuler canine and mandibular first premolar have been completed; and nearly half the root of the upper first premolar is complete

there is significant root development

of the mandibular second premolar. maxillary canine, and maxillary second premolar

completion of the roots of the mandibular incisor teeth and near completion of the roots of the maxillary laterals.

Dental age 11

Dental age 12

Dental age 13,14 & 15

Several reasonable normal variation in eruption sequence have clinical

significant and should be recognized:

1. Eruption of the second molar ahead to the second premolar in the mandibular arch,

2. Eruption of the canines ahead to the first premolar in the maxillary arch

3. Asymmetries in the eruption between the right and left sides.

SPACE RELATIONSHIP IN REPLACEMENT OF THE INCISORS

Incisor liability: the difference between the the amount of the space needed for the incisors and the amount available for them

THE SPACE RELATIONSHIP IN REPLACEMENT OF CANINES AND PREMOLARS.

2.5

1.5

Leeway space

Controlling factors:At the time the primary second molars are lost. Both the maxillary and mandibular molars tend to shift mesially into the leeway space. but the mandibular molar normally moves mesially more than its maxillary counterpart.

a characteristic of the growth pattern at this age is more growth of the mandible than the maxilla, so that a relative deficient mandibule gradually catches up.