Dr. Bushra Rashid Noaman Eruption of teeth Dr. Bushra Rashid Noaman

Normal eruption process

Objectives The factors that have been related to the eruption of teeth Chronologic development And eruption of the teeth Sequence of eruption of the permanent teeth Variations in sequence of eruption

The factors that have been related to the eruption of teeth include , The factors that have been related to the eruption of teeth include

1.elongation of the root

2. forces exerted by the vascular tissues around and beneath the root

3. growth of the alveolar bone, 4. Growth of dentin 5 3.growth of the alveolar bone, 4. Growth of dentin 5. growth and pull of the periodontal membrane, 6. presence of a viable dental follicle

7. hormonal influences 8. pressure from the muscular action 9 7. hormonal influences 8.pressure from the muscular action 9. resorption of the alveolar crest.

hormonal influence in tooth eruption pituitary growth hormone thyroid hormone and parathyroid hormone Hormones protein is required for tooth eruption.

For permanent teeth Variations of 6 months on either side of the usual eruption date may be considered normal for a given child.

Tooth eruption is a series of metabolic events in alveolar bone characterized by bone resorption and bone formation on opposite sides of the dental follicle and the tooth does not contribute to this process."

So Teeth erupt before the root development is complete. Tooth emergence appeared to be more closely associated with the stage of root formation than with the chronologic or skeletal age of the child Q. When does the time of clinical emergence of a tooth into the oral cavity approximately three fourths of root formation had occurred. So Teeth erupt before the root development is complete.

Primary root completion nearly 12-18 months after eruption Most favorable eruption of primary teeth: ABDCE

Root of the primary tooth start to resorb directly after root completion this called physiologic resorption Eruption of the permanent tooth cause the root resorption of the primary tooth root from the inner side of the root this will continue until the exfoliation of the primary tooth

5 years for permanent teeth. Q. when the tooth starts to move toward the occlussion? Each tooth starts to move toward occlusion at approximately the time of crown calcification completion.“ Q. How much the interval from crown completion until the tooth is in full occlusion ? is approximately 5 years for permanent teeth. In primary teeth differ in anterior and posterior teeth so it is between 4-18 months

Five years old child

CHRONOLOGIC DEVELOPMENT AND ERUPTION OF THE TEETH

molar molar

6-7 MONTHS INFANT 14 MONTHS INFANT

Desirable eruption sequence for the permanent teeth the most common sequence of eruption of permanent teeth in the mandible is 6, 1, 2, 3, 4,5, and 7. the maxillary permanent teeth is 6, 1,2, 4, 5, 3, and 7.

The mandibular first permanent molars are often the first permanent teeth to erupt. They are quickly followed by the mandibular central incisors.

Why this sequence is necessary? This sequence aids in having healthy occlusion by: 1. maintaining adequate arch length 2. preventing lingual tipping of the incisors.

VARIATIONS IN SEQUENCE OF ERUPTION

1. PREMATURE LOSS OF PRIMARY MOLARS (INFLUENCE OF PREMATURE LOSS OF PRIMARY MOLARS ON ERUPTION TIME OF THEIR SUCCESSORS)

Early extraction of primary molars in children who lose primary molars before 7 years of age will cause: Eruption of the premolar teeth is delayed

premature loss of primary molars At 8, 9, and 10 years of age, premolar eruption is greatly accelerated.

2. Early loss of primary canine in the mandible will cause lingual tipping of the mandibular incisors

Lingual tipping of the incisors causes : 1.a loss of arch length 2. allows the development of an increased overbite. So if there is early loss of lower primary canines you must construct a space maintainer.