Eruption & shedding

• What is the term for two sets of dentition in humans?

  Diphodont
• What are the three types of dentition in humans?

  Primary, mixed, and secondary dentition
• What age range does primary dentition occur?

  6 months to 6 years
• What age range does mixed dentition occur?

  6 to 12 years
• What age does secondary dentition begin?

  After 12 years
• What does eruption refer to in dental terms?

  Movement of the tooth to its functional position
• What are the three types of tooth movement?

  Pre-eruptive, eruptive, and post-eruptive
• What occurs during pre-eruptive tooth movement?

  Tooth germs move within jaw tissues
• What happens to tooth buds as they grow in size?

  They get crowded in the jaw
• How do molars and anteriors move during jaw growth?

  Molars move backward, anteriors move forward
• Where do permanent anterior tooth germs develop?

  Lingual to primary anterior teeth
• Where are premolar tooth germs positioned?

  Between the roots of deciduous molars
• How do permanent molar tooth germs develop?

  From backward extension of dental lamina
• What is the inclination of molar tooth germs in the mandible?

  Mesial inclination
• Why does pre-eruptive tooth movement occur?

  Due to growth and remodeling of the jaw
• What histologic feature is involved in pre-eruptive tooth movement?

  Remodeling of the bony wall of the crypt
• What is the definition of eruptive tooth movement?

  Movement from developmental to functional position
• What is the intraosseous phase of eruptive tooth movement?

  1-10μ/day
• What is the extraosseous phase of eruptive tooth movement?

  75μ/day
• What environmental factors affect eruptive tooth movement?

  Muscle forces, contact with teeth, habits
• What are the stages of tooth formation?

  Root formation, movement, emergence, post-eruptive movement
• What is required for root formation?

  Space for root formation
• What occurs during the movement stage of tooth formation?

  Teeth move incisally or occlusally
• What happens during the emergence stage of tooth formation?

  Tooth crown penetrates fused epithelial layers
• What is the purpose of post-eruptive movement?

  To maintain contact with opposing crowns
• What significant events occur during eruptive tooth movement?

  Root formation, PDL remodeling, dentogingival junction
• What is the function of the gubernacular canal?

  Guides the permanent tooth as it erupts
• What happens to the gubernacular canal during eruption?

  It widens due to osteoclastic activity
• What are the three categories of post-eruptive movements?

  Accommodation for growth, wear, and interproximal wear
• When does accommodation for growth primarily occur?

  Between 14 to 18 years
• How does compensation for occlusal wear occur?

  By deposition of cementum around the apex
• What compensates for interproximal wear?

  Mesial or approximal drift
• What causes mesial drift?

  Contraction of transseptal fibers
• How does bone tissue adapt during mesial drift?

  Resorption on pressure side, apposition on pull side
• What generates anterior occlusal force?

  Mesial inclination of teeth during clenching
• What soft tissues contribute to mesial drift?

  Buccal mucosa and tongue
• What are the mechanisms of tooth eruption?

  Root growth, bone remodeling, pulp growth
• What does the root growth theory suggest?

  Root growth forces the crown through the gums
• What are some contradictions to the root growth theory?

  Eruption occurs after root completion
• What happens to teeth after surgical removal of Hertwig's epithelial root sheath?

  Eruption can still occur