Risk Of Ortho Flashcards
1.The tissues of the periodontal ligament and gingivae remodel following orthodontic tooth movement. In relation to this remodelling process which of the following statements is true?
A Collagen fibres in the gingivae remodel within a minimum of 3 to 4 months, the periodontal ligament fibres remodel within a minimum of 3-6 months and supracrestal fibres in the gingivae remodel in 6-9 months.
B Collagen fibres in the periodontal ligament remodel within a minimum of 3 to 4 months, the gingival fibres remodel within a minimum of 6 months and supracrestal fibres in the gingivae may take up to 12 months or more to remodel.
C Collagen fibres in the periodontal ligament remodel within a minimum of 1 month , gingival fibres require at least 4-6 months to remodel but supracrestal fibres in the gingivae will require a minimum of 18-24 months.
D. Gingival fibres remodel within a minimum of 3-4 months, supracrestal fibres are fully remodelled within 8 months but periodontal ligament fibres take a minimum of 12months to remodel.
B - Collagen fibres in the periodontal ligament remodel within a minimum 3-4 months, the gingival fibres remodel within a minimum of 6 months and supra-crestal fibres in the gingivae may take up to 12 months to model
Which of the following is NOT a procedure that may reduce the potential for teeth to Relaspe following orthodontic movement.
A. Circumferential supracrestal fiberotomy
B. Interproximal enamel reduction
C. Frenectomy
D. Creation of canine-guided occlusion
D- Creation of canine guidance
Enhances orthodontic stability
Certain features of malocclusion are known to be more unstable than others when corrected with Orthodontic appliances. In such cases a fixed retainer may be indicated.
Which of the following pre-treatment features of malocclusion would not be a specific indication for a fixed retainer:
A. An unerupted palatally ectopic canine which has been surgically exposed and aligned
B. An upper midline diastema which has been closed with a sectional fixed appliance
C. A 9mm overjet which has been reduced to 2mm with both functional and fixed appliances and the patient has competent lips
D. A rotated upper right lateral incisor in a 16 year old patient
C. A 9mm overjet which has been reduced to 2mm with both functional and fixed appliances and the patient has competent lips
A 9mm overjet which has been reduced to 2mm with both functional and fixed appliances should not have increased risk of instability if the lips are competent at the end of treatment. If the patient was still growing a functional appliance worn at night only could be provided as ‘ retainer’ to maintain the A-P correction.
4.Which of the following has not been shown to reduce the reduce the incidence of white spot lesions during Orthodontic treatment ?
A. Daily use of 0.05% sodium fluoride mouthwash
Feedback:
B. Calcium phosphopeptide-amorphous calcium phosphate (CPP-ACP) in any modality
C. Professionally applied topical fluoride around orthodontic brackets
D. Incorporation of Fluoride into an Orthodontic bracket base
D. Incorporation of fluid into orthodontic bracket
Fluoride has not been incorporated into an orthodontic Bracket Silver, Zinc oxide and titanium dioxide coated brackets are currently being investigated for preventing decalcification.
In order to mitigate the effects of orthodontically induced inflammatory root resorption during fixed appliance treatment, which of the following statements is true?
A. Orthodontic forces will reduce the likelihood of inducing root resorption if they are kept light and best applied over a prolonged period of time.
B. Orthodontic forces will reduce the likelihood of inducing root resorption if they are kept light and applied for only a short treatment time .
C. Orthodontic forces will reduce the likelihood of inducing root resorption if they incorporate extrusive tooth movement as teeth are moved over a long distance
D. Orthodontic forces will reduce the likelihood of inducing root resorption if they avoid intrusive tooth movement and are applied over a prolonged period of time.
B. Orthodontic forces will reduce the likelihood of inducing root resorption if they are kept light and applied for only a short treatment time
Which of the following statements is true?
A. A Hawley retainer is better at allowing the posterior teeth to settle into occlusion after Orthodontic fixed appliance treatment than a pressure formed retainer
B. A Hawley retainer is more effective at maintaining lower incisor position than a pressure formed retainer.
C. A Hawley retainer is not robust enough to cope with the forces of mastication and so must be removed when a patient is eating.
D . A Hawley retainer costs less to fabricate than a pressure formed thermoplastic retainer
A. A Hawley retainer is better at allowing the posterior teeth to settle into occlusion after Orthodontic fixed appliance treatment than a pressure formed retainer
A 16 year-old female patient has just completed a course of orthodontic fixed appliance treatment. She is concerned about the ‘white spots’ that have appeared on her upper incisors during fixed appliance treatment. Which of the following treatment options would be most suitable to try and address her aesthetic complaints?
A. Provision of porcelain veneers on the labial surface of her affected upper incisors
B. Application of ICON resin infiltrate
C. Oral hygiene advice to brush 1 x daily with 1450ppm fluoride tooth paste
D. External Bleaching of the enamel surface
B Application of ICON resin infiltrate
What percentage of patients can be expected to suffer from severe root resorption ( exceeding 4mm or more than one third of the original root length ) as a result of undergoing orthodontic fixed appliance treatment?
A. < 1%
B. 1-5%
C. 5-10%
D. 10-20%
B 1-5%
Which of the following patients presents the greatest risk of developing gingival recession during Orthodontic Fixed appliance treatment ?
A. Patient A who has pre-treatment evidence of decalcification (white spots) on their dentition and a thin gingival biotype.
B. Patient B who is has hypodontia and is going to have a longer than average course of appliance treatment with dental implants inserted. They have a mildly hyperplastic gingivae.
C. Patient C who has a mildly crowded class I malocclusion and will be treated non -extraction. Space will be gained by expanding both the upper and lower arches. They have a thin gingival biotype.
Feedback:
Well done ! This is the correct answer. The factors which contribute to increased risk of gingival recession include a thin gingival biotype, pre-existing narrow width of attached gingivae , any treatment which will tend to move the teeth towards the cortical plates of the alveolar bone. Superimposed on this poor oral hygiene and plaque retention will compound the problem.
D. Patient D who has a moderately crowded dentition and will be treated with extractions x 4 and upper and lower fixed appliances. They have a tendency to a thin gingival biotype.
C - Patient who has mildly crowded class 1 malocclusion and will be treated non extraction, space will be gained by expanding noth upper and lower arches.
They have a thin gingival bio type.
What factors contribute to increased risk of gingival recession following orthodontic treatment
The factors which contribute to increased risk of gingival recession are;
- thin gingival bio type
- pre.existing narrow width of attached gingivae
- any treatment that will tend to move towards the cortical plates of the alveolar bone
- superimposed on this poor OH and plaque retention will compound the problem
Which of the following treatment outcomes will have the greatest likelihood of post-treatment stability?
A. Correcting an anterior crossbite and achieving a 2mm positive overjet
B. Treating a class II division II malocclusion to achieve an increased interincisal angulation (approx. 160 degrees)
C. Correcting an anterior crossbite and achieving a 50% overbite relationship between upper and lower incisors.
D. Reducing an overjet in a Class II division I malocclusion so that the lower incisors fall under the control of the upper lip
C - correcting an anterior cross bite and achieving 50% overbite relationship between upper and lower incisors
