Orthodontics Level 4 unit A: Flashcards
What are the goals of orthodontic treatment?
In the modern age, there are three reasons for doing orthodontics—listed here in their order of importance:
Primarily, to help patients overcome psychosocial handicaps created by discrimination based on facial appearance
To improve function of the teeth and jaws
To improve oral health
True or false. Bringing teeth into the correct occlusion and ideal alignment is enough for orthodontic treatment?
False, it isn’t enough to just replace missing teeth, or to bring the teeth into ideal alignment and occlusion without considering the esthetic outcome
If the dental and facial esthetics are not satisfactory, it’s not satisfactory treatment—because then the desired improvement in quality of life would not achieved.
Is there a relationship between malocclusion and oral health?
Hard tissue lesions: little or no relationship
Periodontal disease: a weak relationship
How do third molars typically erupt?
Third molars can be put into three categories:
(1) those that erupt and become a functional part of the dental arch;
(2) those that erupt into the mouth, but are only partially exposed and are not in occlusion;
(3) those that have not entered the oral cavity.
What kind of problem can unerupted 3rd molars develop? How should they be managed?
They can produce health risks related to the bacterial flora around them and development of chronic inflammation; they are a lesser health risk but may become cystic and damage other teeth or produce significant bone lesions. Follow-up radiographs to monitor their status are needed if they are retained.
What problem can partially erupted third molars lead to?
When the crown of the tooth breaks through the soft tissue and is exposed to the oral environment, bacteria can and do penetrate deeply along the crown.
An increased probing depth is found, and this is a hospitable area for the anaerobic bacteria that are now known to be the cause of periodontal disease. (not necessarily causative of periodontal disease)
Should 3rd molars be extracted if they only erupt partially?
The current guidelines:
Removal of exposed 3rd molars decreases the chances of early periodontal disease
If a partially erupted 3rd molar is retained, monitoring that includes probes for evaluation of the bacterial flora is needed
An episode of pericoronitis is an indication for extraction
Recovery after 3rd molar extraction is faster and less problematic in teen-agers
What factors are influenced by dental occlusion?
Masticatory efficiency (although no need for perfect occlusion as teeth barely even touch during chewing)
TMD/occlusion
What food is hard to chew with an open bite or large overjet?
pizza often offers a challenge is you have an open bite or large overje
What kind of malocclusion is associated with crossbite?
lateral shift, however, 1 in 6 people with lateral shift have RMD
What is the chance of developing TMD with class 3 and class 2 deep bites?
there’s only about a 10% chance of correctly predicting that TMD will develop in a patient with these malocclusions.
Perfect occlusion decreases the chance of tmd but doesn’t eliminate it
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What do protruding upper incisors give as an impression to other people?
That a person is stupid.
psychosocial impacts of dentition
Protruding upper incisors suggest that you’re an idiot
Bad teeth (decayed, broken, missing, obviously crowded, or protrusive) suggest that you’re from a lower socioeconomic class, probably aren’t well educated, and don’t take good care of yourself.
(3) Chin prominence (strength) means a lot.n a male, a strong chin is associated with a more powerful personality, while a weak chin is associated with general weakness and doubtful intelligence (your upper incisors will protrude, of course, if your mandible is deficient).
What are the reasons where orthodontic extractions is indicated?
2 main reasons:
Correcting crowding/protrusion
Camouflage of jaw discrepancy
When are extractions done for crowding/protrusion?
As a general rule, extraction for crowding/protrusion is done for patients with Class I malocclusion
When is extraction for camouflage done?
Class II or III problems.
What determines whether teeth protrude or are crowded?
if there’s not enough room for the teeth, soft tissue characteristics of individual patients determine whether they’re crowded, are protrusive, or have some aspects of both.
What determines whether or not teeth are too protrusive?
Lips are separated at rest and are strained/everted on closure.
What is the purpose of extraction in the treatment of crowding/protrusion?
Providing space to align crowded teeth without protruding them
Provide space to retract protruded teeth to normal relationship with the lips and the jaw
Or both.
Why did extractions increase and decrease in orthodontics over the years?
In the early 20th centures expansion of the arches was the usual treatment and by mid 20th century extractions increased in frequency to create a more stable result.
Increased use of bands in the mid 20th century also meant more patients needed extractions.
Why in recent times is extraction much less common than it used to be in the id 20th century?
Too much incisor retraction can harm facial aesthetics in some patient
Research data in the 1970s showed that relapse into crowding still occurred in some patients after extractions were done reducing enthusiasm for extraction.
Bonding of attachments largely replaced banding so band space wasn’t a consideration anymore
some practitioners linked premolar extraction–wrongly–to the development of TMD. Those claims, though false, led to a widely reported lawsuit and a more defensive approach by some practitioners.
most clinicians agree that it is more difficult and takes longer to treat extraction cases well, which tends to reduce enthusiasm for extraction in borderline cases.
Why is orthodontic expansion more successful now than it was many years ago when extractions were more common?
If you can keep the first permanent molars from shifting forward into the leeway space then that space can be used for anterior teeth.
Transverse expansion of the dental arches has been shown to be more stable than antero-posterior expansion. In current treatment transverse expansion is emphasized.
How much expansion can be tolerated?
Lower incisors can be moved forward 2mm if they’re not already protrusive
Very little expansion across canines is stable
2 - 3mm expansion across the premolars and molars is tolerated.
Which of the following are reasons for the decline in the percentage of patients with premolar extraction to treat crowding/protrusion?
a. Effects on facial esthetics
b. Instability even after extractions
c. Introduction of bonded brackets to replace bands
d. Considerations of treatment efficiency
All of the above
