18 Questions
How many teeth will erupt every 4 months starting at the age of 7 months?
4
At what age will the 4 teeth erupt according to the ERUPTION Rule of 4?
7 months
How many years does it take for the root formation of the maxillary central incisor to complete?
10 years
What is a characteristic of enamel?
It is highly mineralized and acellular
At what age will the second molar erupt in the maxillary permanent teeth?
12-13 years
What is the age range for the eruption of the third molar in the maxillary permanent teeth?
17-21 years
What is the primary mechanism of tooth eruption according to the Bone Growth Theory?
Growth of the alveolar bone pulls the tooth outwards
What is the name of the theory that suggests eruption is due to the increased blood pressure in the diminishing pulp cavity?
Vascular Pressure Theory
According to the Pulp Growth Theory, what provides the eruptive force for tooth eruption?
Growth of the pulp
At what age do central incisors typically erupt in the maxilla?
11-13 months
How many teeth are present in a 15-month-old child?
12
What is the name of the theory that suggests the presence of many blood vessels in the apical region causes the formation of tissue fluid, leading to tooth eruption?
Vascularity or Tissue Fluid Pressure Theory
What is the reason for localized failure in the formation of accessory canals?
Failure in the formation of Hertwig's sheath during embryonic stages
What type of tooth movement is responsible for maintaining the position of the erupted tooth in occlusion?
Posteruptive tooth movement
Which theory of eruption is disproven by the experiment where the pulp was removed and root filled, and eruption ceased?
Pulp growth theory
What happens to the REE during the eruption of a tooth into the oral cavity?
It fuses with the oral epithelium, forming the dentogingival junction
What is the result of extracting an antagonist after root formation is complete?
Supra-eruption may occur
What is the description of the tooth movement made by the deciduous and permanent tooth germs within tissues of the jaw before they begin to erupt?
Preeruptive tooth movement
Study Notes
Eruption of Primary Teeth
- 4 teeth erupt every 4 months starting at the age of 7 months.
- At 7 months, 4 teeth are present (A).
- At 11 months, 8 teeth are present (AB).
- At 15 months, 12 teeth are present (ABD).
- At 19 months, 16 teeth are present (ABDC).
- At 23 months, 20 teeth are present (ABDCE).
Eruption and Root Completion of Permanent Teeth
Maxillary Teeth
- Central incisor: eruption at 7-8 years, root formation complete at 10 years.
- Lateral incisor: eruption at 8-9 years, root formation complete at 11 years.
- Canine: eruption at 11-12 years, root formation complete at 13-15 years.
- First premolar: eruption at 10-11 years, root formation complete at 12-13 years.
- Second premolar: eruption at 10-12 years, root formation complete at 12-14 years.
- First molar: eruption at 6-7 years, root formation complete at 9-10 years.
- Second molar: eruption at 12-13 years, root formation complete at 14-16 years.
- Third molar: eruption at 17-21 years, root formation complete at 18-25 years.
Mandibular Teeth
- Central incisor: eruption at 6-7 years, root formation complete at 10 years.
- Lateral incisor: eruption at 7-8 years, root formation complete at 11 years.
- Canine: eruption at 9-10 years, root formation complete at 13-15 years.
- First premolar: eruption at 10-12 years, root formation complete at 12-13 years.
- Second premolar: eruption at 11-12 years, root formation complete at 12-14 years.
- First molar: eruption at 6-7 years, root formation complete at 9-10 years.
- Second molar: eruption at 11-13 years, root formation complete at 14-16 years.
- Third molar: eruption at 17-21 years, root formation complete at 18-25 years.
Dental Tissues
- Enamel: highly mineralized and acellular.
Theories on Eruption
- Root Growth Theory: pressure from the elongating root against the base of the alveolar crypt causes the eruption of the tooth.
- Vascular Pressure Theory: eruption is due to increased blood pressure in the diminishing pulp cavity as the tooth develops.
- Pulp Growth Theory: growth of the pulp provides eruptive force.
- Bone Growth Theory: growth of the alveolar bone pulls the tooth outwards by the periodontal fibers.
- Vascularity or Tissue Fluid Pressure Theory: presence of many blood vessels in the apical region causes the formation of tissue fluid in a small closed space, which exerts a steady pressure.
Eruption and Root Completion of Primary Teeth
Maxillary Teeth
- Central incisor: eruption at 10 (8-12) months, root formation complete at 1 ½ years.
- Lateral incisor: eruption at 11 (9-13) months, root formation complete at 2 years.
- Canine: eruption at 19 (16-22) months, root formation complete at 3 ¼ years.
- First molar: eruption at 16 (boys: 13-19 months, girls: 14-18 months), root formation complete at 2 ½ years.
- Second molar: eruption at 29 (25-33) months, root formation complete at 3 years.
Mandibular Teeth
- Central incisor: eruption at 8 (6-10) months, root formation complete at 1 ½ years.
- Lateral incisor: eruption at 13 (10-16) months, root formation complete at 1 ½ years.
- Canine: eruption at 20 (17-23) months, root formation complete at 3 ¼ years.
- First molar: eruption at 16 (14-18) months, root formation complete at 2 ¼ years.
- Second molar: eruption at 27 (boys: 23-31 months, girls: 24-30 months), root formation complete at 3 years.
Miscellaneous
- Accessory canals: formed due to localized failure in the formation of Hertwig's sheath during embryonic stages of tooth formation.
- Eruptive movements of teeth: preeruptive, eruptive, and posteruptive.
- At 15 months, the child has 12 teeth (ABD).
Test your knowledge of tooth eruption theories, including the root growth theory and vascular pressure theory, and their supporting evidence. Learn about the different mechanisms behind tooth eruption and how they impact dental development.
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