Lecture 7 Flashcards
Match the type of orthodontic archwire to the description…
Strong, stiff, formable and has been used routinely for many years
Softer than stainless steel making it more formable and then the wire can be heat treated to make it harder before it is inserted into the orthodontic appliance
Very useful during initial stages of alignment due to their exceptional ability to apply light force over a large range of activation and due to its shape memory and superelasticity
Offers a highly desirable combination of strength and springiness as well as a good formability. They fall in between stainless steel and nickel titanium alloys
Stainless steel
Chromium alloys
Nickel-titanium alloys
Beta-titanium
What are superelastic nickel titanium alloy wires? what are heat activated nickel titanium alloy wires?
Can be deformed and will rebound back to their original shape
Regain their original shape after being exposed to heat
Orthodontic appliances should not be reactivated more frequently than at ___ week intervals
3
Undermining resorption typically requires ____ days and tooth movement is essentially complete in this length of time
There is an equal or longer period for ____ regeneration and repair that should be observed before the force applied again (this is why ortho patients are seen on a monthly basis)
7-14 days
PDL
What can happen if you activate an ortho appliance too frequently?
It can short circuit the repair process and can produce damage to the teeth and/or bone that a longer appointment interval would have prevented or would have at least minimized
True or false… Since the presence of orthodontic appliances increases the amount f gingival inflammation, even with good hygiene, loss of alveolar bone height occurs during treatment and after treatmetn is complete
During treatment true
After treatment false
How much bone loss occurs due to ortho treatment?
Less than 0.5mm and rarely exceeds 1mm
The most probable reason that alveolar bone height is minimally affected is that the position of the teeth determines the position of the alveolar bone. (When teeth erupt or are moved they bring bone with them, so crestal bone loss from orthodontic treatment is rarely seen)
When does bone loss occur in ortho treatment?
In the presence of active periodontal disease. But once the perio disease is under control these teeth can be moved and can have a good bony response
True or false… teeth, if extruded can be pulled out of bone
False.. in the absence of pathological factors, a tooth that erupts too much simply carries alveolar bone with it. The tooth does not erupt out of the bone. Or when a tooth is intruded it doesn’t move into the bone.
Can intruding a tooth correct periodontal bone loss?
Little evidence supports this
What happens to the alveolar bone with a tooth is intruded or extruded?
When teeth are intruded or extruded, the alveolar bone moves with the tooth, thus maintaining the distance between the alveolar crest and the CEJ on the tooth. (In other words, the patient’s biological width (3mm) stays about the same
True or false… unless a tooth erupts into an area of the dental arch, the alveolar bone will not form there.
True
this is why a patient with congenitally missing teeth have no alveolar bone and why dentures must be relined every few years
Radiographically it can be observed that the PDL space [widens/narrows] during orthodontic tooth movement. what does this mean?
Widens
The combination of a wider PDL space and a somewhat disorganized ligament means that some increase in mobility will be observed in every patient.
True or false… ortho patients have increased mobility during treatment
True
What causes an increase in mobility in ortho patients?
Heavier force and greater undermining resorption
