Lecture 5 Tooth Movement Flashcards
What are the 3 ways tooth movement is categorized?
preeruptive, eruptive, posteruptive
Which tooth movement is made by the deciduous and permanent teeth within tissues of the jaw before they begin to erupt?
preeruptive tooth movement
Which tooth movement is made by a tooth to move form its position within the bone of the jaw to its functional position in occlusion? This phase is sometimes subdivided into intraosseous and extraosseous components.
eruptive tooth movement
Which tooth movement maintains the position of the erupted tooth in occlusion while the jaws continue to grow and compensate for occlusal and proximal tooth wear?
posteruptive tooth movement
What are the two factors of preeruptive tooth movement?
total movement of the tooth (bodily movement) and growth of one part of the tooth while the rest of the tooth remains fixed
T/F During tooth development, alveolar bone grows down towards the dental lamina and grows around the developing deciduous and successional teeth.
False. The alveolar bone grows UP towards the dental lamina.
What does introosseous mean?
Occurs within bone
What type of growth causes only bone resorption to accommodate the change in shape of the tooth as it grows?
eccentric growth
What kind of canals are cords of fibrous tissue that connect the tooth follicle to the lamina propria of the oral muscosa?
gubernacular canals
What do gubernacular canals often contain?
cellular remnants of the dental lamina
During tooth eruption, what kind of cells widen a canal through the bone producing an eruptive pathway as seen in the dried bone specimen?
osteoclasts
T/F Successional incisors and canines erupt facially to the deciduous teeth.
False. Successional incisors and canines erupt LINGUALY to the deciduous teeth.
What are the 3 proposed mechanisms of eruptive tooth movement?
root formation, alveolar bone remodeling, PDL formation
T/F Root formation is a not a cause of eruption.
True. Even when rootless teeth erupt, some teeth erupt a greater distance than the total length of their roots.
T/F When a tooth is removed or replaced with a replica without disturbing the dental follicle, an eruptive pathway still forms within the bone overlying the tooth.
True
T/F If a developing tooth is replaced by a metal or silicone replica without disturbing the dental follicle, the replica will not erupt.
False. The replica will erupt.
T/F Dental follicle and certain cell-signaling molecules are involved with bone remodeling and will cause eruption.
False. It will not cause eruption. Bone resorption over the tooth clears the path for the tooth but it doesn’t move the tooth.
T/F PDL formation is the best theory for eruptive teeth.
True. PDL fibroblasts exhibit significant traction power and have a cytoskeleton that enables them to contract. Since they are well-anchored and can generate significant motive forces they probably contribute to eruptive tooth movement.
T/F Resorption of deciduous teeth roots occurs primarily on the lingual surface.
True.
What is the name of the cells that remove dental tissue by resorption of dental hard tissue and is historically identical to osteoclasts?
odontoclasts
What type of cells are derived from circulating monocytes that develop into macrophages and migrate into the resorption site where they fuse to form the characteristic multinucleated cells with an active ruffled border?
odontoclasts
What type of tooth movement is made by the tooth after it has reached its functional position int he occlusal plane?
posteruptive tooth movement
What are the 3 reasons of posteruptive tooth movement?
accomodation for growth, compensation for continued occlusal wear, and accomodation for interproximal wear.
Which reason of posteruptive tooth movement happens when a tooth socket remodels between the ages of 14-18 forms new bone at the alveolar crest and on the socket floor to keep up with the increasing height of the jaws?
accomodation for growth
Which reason of posteruptive tooth movement has axial movement to compensate for wear is probably achieved by the same mechanism as eruptive tooth movement?
compensation for continued occlusal wear
Which reason of posteruptive tooth movement has mesial drift that compensates for wear on the points of contact between teeth?
accommodation for interproximal wear
What are the mechanisms of accommodation for interproximal wear?
contraction of the transseptal ligament between teeth, soft tissue pressure, and the anterior component of occlusal force
T/F Plasticity of the PDL and alveolar bone makes orthodontic tooth movement possible.
True
Which type of cells differentiate and reabsorb alveolar bone on the pressure (compression) side of the socket?
osteoclasts
What is the process called when PDL undergoes loss of cells from an area of the ligament due to trauma?
hyalinization
Which type(s) of cells remodel bone and PDL on the tension side of the socket?
osteoblasts and fibroblasts
T/F Cementum is affected by light forces.
False. Cementum should not be affected by light forces because cementum resists resorption more than bone.
What is the result of rapid movement that can damage root canal vessels?
pulp necrosis
What initiates resorption of the root?
pressure from the erupting successional tooth
