Orthodontics Flashcards
In Volker’s 2016 case report “Management of Mesioverted Maxillary Canine Teeth and Linguoverted Mandibular Canine Teeth,” how was translational/bodily movement achieved?
JVD 2016
Elastomeric masel chain and incline planes on maxillary canines
Requires 2 forces simultaneously applied to the crown creating movement of root and crown in same direction
In Volker’s 2016 case report “Management of Mesioverted Maxillary Canine Teeth and Linguoverted Mandibular Canine Teeth,” how quickly was normal occlusion achieved with orthodontic treatment?
JVD 2016
14 days
Stretching and compressing the PDL result in stimulation of osteoblasts or osteoclasts?
Holstrom Vet Dental Techniques
Stretching PDL: osteoblasts
Compressing PDL: osteoclasts
Translation or bodily movement requires how much more force than tipping movement?
Holstrom Vet Dental Techniques
2x the amount of force
Which orthodontic movements require the least and greatest amount of force?
Holstrom Vet Dental Techniques
Least: Extrusion
Most: Intrusion
How long is the retention period typically in veterinary orthodontics?
Holstrom Vet Dental Techniques
2-4 weeks
How is the diameter of orthodontic wire measured?
Holstrom Vet Dental Techniques
thousandths of an inch
The higher the number, the greater the cross sectional area and relative rigidity of the wire
In human orthodontics how much time per day is required for an orthodontic removable appliance to be worn to produce tooth movement?
4-6 hour per day
After ~4 hours of light orthodontic pressure against a tooth what molecule levels become increased?
cAMP
After how many days of sustained light pressure does tooth movement begin?
~ 2 days
When heavy pressure is used for a sustained period of time leading to cell death in compressed area what type of resorption occurs and how delayed is tooth movement?
Undermining resorption
Movement occurs in 7-14 days vs 2 days (frontal resorption)
When PDL cells are compressed does RANKL, TNF-alpha, MMPs, TGF-beta and prostaglandin expression increase or decrease?
Increase
In tipping movement where is the true center of rotation/fulcrum?
Junction of the middle and apical thirds of the root
What is the optimal force range for tipping movements?
35-60 g
Lighter forces better for tipping: the lighter the force applied, the more apical the fulcrum
What ratio determines the type of tooth movement?
The moment produced by the force applied to move a tooth (MF) / the counterbalancing moment produced by the couple used to control lroot position (MC)
When the MF/MC ratio = 0 what type of movement is produced?
Tipping
Tooth rotates around the center of resistance
When the MC/MF ratio > 1 what type of movement occurs?
Radicular
Apex carries primary movement, fulcrum at the middle and cervical third of the root
When the MC/MF ratio = 1 what type of movement occurs?
Translation/bodily movement
crown and apex travel in same direction.
What are the four aims of orthodontics?
- Proper assessment and supervision of the occlusion
- Removal of etiological factors that may disrupt normal growth patterns (interceptive action)
- To correct conditions that may allow the occlusion to deteriorate (preventative measures)
- To establish and maintain as functional and as close to normal an occlusion (corrective acts)
What can be done to help counteract the recoil movements that tend to occur when attempting rotation/torsion movements?
wiggs
Rotate teeth with lighter pressure over longer period of time
Use alternating periods of movement and stabilization
Retainer applied for several months
What is the force range required for rotation?
VCNA
50-75g
What are the force range requirements for extrusion?
VCNA
50-75 g
According to the VCNA (differs from Holstrom) what type of orthodontic movement requires the least force?
Intrusion 15-25 g
What happens to the relative root dimensions secondary to orthodontic movement?
They become shorter but not thinner
It is generally agreed that what developmental tooth structure is necessary for eruption to occur?
Ten Cates
Dental follicle
What is the hyalinization process of orthodontic movement?
When force is great enough to totally occlude PDL blood vessels, sterile necrosis of compressed cells occurs which causes a delay of ~ 7-14 days for cellular elements to invade necrotic area and stimulate resorption and tooth movement
Heavier orthodontic forces cause faster or slower tooth movement?
Slower due to hyalinization
Clinically demonstrateable root resorption following orthodontic movement usually occurs only after application of heavy force and movement of teeth for more than how many days?
30 days