robbypowell's version from 2016-10-20 01:00

bioclinical considerations

Question Answer
What has a more profound effect on tooth movement... force magnitude or duration?Duration
Schwarz (1932) described the optimum orthodontic force as ____ grams per square centimeter of root surface. This value was related to magnitude needed to occlude the blood vessels in PDL; More contemporary value is ___ grams per square cm20-26; 7-10
In general a _______ (lighter/heavier) force is considered to be more optimal for orthodontic movement... though it depends on the situationLighter
1 N = _____ grams100 grams
Invisalign is best for what type of orthodontic tooth movementsTipping
______ refers to avascular areas of bone resulting form sustained heavy forces, not related to cartilage, related to the surface texture is cell free and glass likeHyalinized
What is the "simplest" form of orthodontic movement?Tipping
What movement is the result of a single force vector applied to a tooth's crownTipping (around COR)
What type of movment: PDL is compressed near the alveolar crest on one side and near the root apex on the opposite side.Tipping
center of rotation is normally located where?approximately 1/2 the length of the root measured from the CEJ
what type of movement: crown and the root apex move in the same direction the same amountTranslation (bodily movement) (no tipping)
what type of movement: PDL on the compression side is uniformly loadedTranslation (bodily movement)
Force level of bodily movement (translation) will need to be approximately _____ that of tipping movementsTWICE (2x)
what type of movement: Force placed through the tooth's center of rotationTranslation (bodily movement)
______ movements are more difficult to accomplish than other tooth movementsIntrusive
what type of movement: force is concentrated over a small area, in the apical region of the socket, the force level must be kept very lightIntrusion (10-20g)
What type of movement: one of the easiest... and ideally creates only tension and no compression in PDLExtrusion
(more/less) force should be used for extrusive movements where the desired outcome has greater crown length?More (attachment apparatus stays behind)
(more/less) force should be used for extrusive movements when to increase alveolar bone height (such as when cultivating bone for implant placement)Less (bring bone and tissue with the tooth)
what type of movement: require the application of two forces equal in magnitude but opposite in directionRotational
application of two forces equal in magnitude but opposite in direction uses a force system called a _____couple
minimal amount of time necessary for clinically observable tooth movement to occur is _________ hours/day6 hours/day (4-8)
_____ forces can cause a mild inflammatory response in the pulp of teeth, and _____ forces can diminish blood supply to pulp and induce plural necrosisLight; Heavy
T/F: Teeth which become necrotic during orthodontic treatment, however, most often have a previous history of trauma or other pulpal insult.True
T/F: Endo-treated teeth cannot be moved by orthodontic therapyFalse (PDL and Pulp are separate entities)
Teeth that have undergone trauma may under go ______ _____ in response to that trauma (ortho movement should probably be counted as a source of trauma in this instance)root resorption
T/F: Endodontically treated teeth which show no sign of resorption before orthodontic treatment are no more susceptible to external root resorption than vital teethTrue
T/F: Endodontically treated teeth are more susceptible to external root resorption than are non ends-treated teethFalse
Which is more resistant to resorption... cementum or bone?Cementum
Which is less resistant to resorption... cementum or bone?bone
Cementum and bone are similar... but what are 4 differences?Cementum: More fluoride (considerably so), non-innervated, non-vascular, less remodeling
cementum is covered by a layer of _______ (a less mineralized form of cementum) and appears to offer a protective function.. sometimes referred to as resorption resistant coatingCementoid
T/F: Areas of root resorption can be detected in most all teeth undergoing tooth movementTrue
Cemental resorption can extend to dentin... if this is repaired with bone deposition then it will result in ______Ankylosis
Pain following ortho adjustment usually lasts how long? and is the result of what?2-4 days; ischemic areas in PDL
When force levels are kept within a physiologic range, the tooth mobility observed is class ___ and is usually limited to mesio-distal and buccal-lingual directionsClass 2
Class 2 mobility in MD and BL directions on orthodontically treated tooth... what does this result mean for the appropriateness of applied force?Appropriate (within physiologic range)
Class 3 mobility, including vertical displacement orthodontically treated tooth... what does this result mean for the appropriateness of applied force?Too heavy
When the area of ankylosis is less than _________% of the root surface area, the tooth will exhibit normal mobility and sound on percussion.10%
If ___% or more of the root surface is included in the ankylotic area, the tooth willl lack normal mobility and and a more highly pitched sound will be heard on percussion20%
3 treatment options to consider for ankylosisExtraction, Individual tooth osteotomy or distraction osteogenesis
What tx related factor most frequently is a risk factor for external root resorption?Force MAGNITUDE
almost 50% of root resorption cases are attributed to ____ _____, esp if homozygous to IL1 beta more likely to experience root resorption Genetic Factors
Patients homozygous to what gene are much more likely to experience root resorption as a result of ortho treatment?IL-1 beta
3 most commonly affected teeth by OIIRR in order of prevalencemaxillary incisors, the mandibular incisors and the first molars
Diagnostic radiographs should be taken in at what point after the initiation of orthodontic treatment to identify early signs of root resorption?6mos - 1yr (6-12mo)
_____ months is the threshold for larger amounts of root resorption6 months
If OIRR is detected early... a _____ to _____ month rest period is recommended2-3 mo
less than ____ mm root resorption is considered mild2mm
___ to ___ mm root resorption is considered moderate2-4mm
greater than ____ mm root resorption is considered severe>4mm (or >1/3 of the root)
sever root resorption is seen in ___ to ___% of patients1-5%
If someone is going to undergo ortho treatment... recommend _____ for pain relief and NOT ______'sTylenol; NOT NSAID's (b/c they inhibit prostaglandins... which are needed for movement)
2 drugs that are inhibitory for tooth movementNSAID's & Bisphosphonates (contraindication)
surgical approach that combines controlled surgical alveolar trauma (corticotomy) with orthodonticsWilckodontics
Wilckodontics claims a lot of benefits... but only one known to be true is what ... and for how long?Accelerated tooth movement, only for 4 months (in humans)
treatment that uses a Screw that creates an injury/insult that activated he osteoblast mediators to enhance bone movementAlveocentesis

optimum force levels for types of movement

Question Answer
Tipping35-60 (g)
Bodily movement (translation)70-120 (g)
Root Uprighting50-100 (g)
Rotation35-60 (g)
Extrusion35-60 (g)
Intrusion10-20 (g)

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