Orthodontics Flashcards
Risk & Benefits-
Patient has an anterior crossbite and requires fixed appliance treatment.
1. Name 4 fluoride supplements you would give the patient to prevent decalcification, naming the dose and frequency? (4)
- Fluoride toothpaste- dose depending on age- 2,800ppm or 5,000ppm (16+) in high risk patients or else 1,450ppm
- Fluoride varnish 22,600 ppm up to 4x yearly
- Fluoride mouthwash 225ppm x1 daily (0.05%
- Fluoride tablet 1mg x1 daily
Name other methods to prevent decalcification other than fluoride supplementation? (2)
- Ensure correct case selection and only perform orthodontics on patient who have good OH or are motivated to achieve good Oh during treatment (motivation, Oh and caries risk key factors for consideration)
- OHI- correct toothbrushing and interdental brushing beneath the wires and around brackets twice daily and after meals, use disclosing tablets to focus on missed areas
- Dietary advice- reduce sugar and try to keep to mealtimes, drink water between meals and avoid carbonated drinks which could reduce pH
- Regular hygiene appointment at GDP
- Fissure sealants
- Chew sugar free gum to stimulate saliva flow
- List 8 potential risk of orthodontic treatment other than decalcification? (4)
- Root resorption
- Gingival recession
- Relapse
- Soft tissue trauma
- Loss of vitality
- Loss of periodontal support
- Wear of opposing teeth from brackets- enamel fracture and wear
- Poor/failed treatment
- Allergy
Invasive as etch the tooth surface.
Planned Extraction of FPM-
1. What are the advantages of planned extraction of first permanent molars? (4)
- Spontaneous space closure
- Caries free dentition
- Reduction in possible orthodontic needs
- Mild buccal segment crowding
What sings are indicative of suitability/appropriate timing for extraction of FPM?
- Start of calcification of the bifurcation of the lower second molars 7’s
- Ideally all premolars and 8’s present
Name 2 disadvantages of planned Extraction of FPM?
- Traumatising to the child and may become dentally anxious after. Requiring further surgical treatment
- May require a GA if child is young and the risks assocaited with this
- Possible distal migration of the 5 and tipping of the 7
Adult Orthodontics-
Trevor is 25 years old and attends your practice complaining that his upper from teeth are slightly crooked and he wants them straightened. He declined orthodontic treatment as a teenager. Clinical examination reveals red marginal gingivitis but an otherwise caries-free unrestored dentition. Clinical investigation shows he has a Class I skeletal pattern with a Class II Division I incisor relationship with proclined upper incisors and he has mild upper anterior crowding. You refer Trevor to an orthodontist.
1. What information, relevant to his provision of orthodontic care, do you need to provide the orthodontist? (5)
- Patient details- name, DOB, sex, CHI, address
- HPC, RMH, RDH
- Patient expectations
- Incisor relationship, Skeletal base relationship (AP, vertical & transverse)
- Teeth present/absent, OH, prognosis of teeth
- Incisor inclination and crowding of lower and upper arch
- OJ, OB, centrelines, molars relationship, canines relationship, crossbite
- IOTN score
- Any radiographs, study models or clinical photographs taken
The orthodontist decides to undertake treatment for Trevor. Trevor attends for a routine check-up with you halfway through orthodontic treatment You notice a debonded bracket and demineralisation around the remaining brackets. How would you manage each of these problems?
- Account for all components- does patient know where debonded bracket is? What happened? (if possible aspiration risk refer to A&E)
- Don’t attempt to rebond bracket as don’t know prescription and if rebond in wrong place can cause issues or worsening of malocclusion
- If on rounded arch wire remove ligature and bracket from wire, tell patient how to clean tooth and refer back to orthodontist
- If on square arch wire can’t remove bracket to simply tell patient it has debonded but out with your remit to rebond it, make sure ligature is secure, inform patient to slide bracket to side to clean tooth and to get an appointment with orthodontist as soon as possible
- Inform patient of demineralisation and explain what it is, the potential long term effects and how it can be prevented
- Give OHI regarding fluoride; prescribe high fluoride toothpaste and give targeted toothbrushing advice
- Apply fluoride varnish 22,600ppm to areas of demineralisation
- Refer back to orthodontist for replacement of bracket
- When Trevor next visits the orthodontist the appliance is remove because of his poor compliance. Trevor returns to your about other treatment options. One possible treatment would be extraction of the upper incisor teeth and provision of an upper partial denture. What would be the potential long term risks of
a) Loss of the upper incisor teeth (3 marks)
- Bone loss
- Drfting and mesial tipping of adjacent teeth
- Difficulty with speech
- Difficulty with mastication
- Poor labial profile
- When Trevor next visits the orthodontist the appliance is remove because of his poor compliance. Trevor returns to your about other treatment options. One possible treatment would be extraction of the upper incisor teeth and provision of an upper partial denture. What would be the potential implications of
a) Provision of an upper removable partial denture (3 marks)
- If patient has poor compliance and OH and this is a potential plaque retentive factor so increased caries risk
- Poor aesthetics
- Psychological and psychosocial impact of wearing denture
- Hard to wear and function in terms of mastication
- Trevor doesn’t want to wear a denture and thinks that crowns should be provided. Why would you advice against this options? (1)
- As he has poor OH and crowns require good Oh to keep in good condition as can be difficult to clean and poor OH can result in gingival recession, perio disease and unstable, unaesthetic crowns. Requirinf early loss of teeth
- Crown preperations are destructive and require removal of alot of tooth tissue
- What advice would you give to Trevor to maintain his oral health in the long-term?
If he has poor OH.
- Standard OHI
- Brush 2x daily with electric TB (using the modified bass techique)
- High risk so high F TP (5000ppm)
- Spit dont rinse
- Brush for 2mins
- Use ID brushes and or floss once a day
- Single tuffed brush to get back of lone standing tooth
- Disclosing tablets for seeing areas to focus on
- Attend dentist regularly
- Minimise sugar in diet
30-year-old patient presents, worries about his class 3 incisor relationship.
1. How would you assess the patient Ap relationship? (3
- Visual assessment - frankfort plane parallel to the floor
- Palpate the skeletal bases - direct palpitation I/O with fingers
- Lateral ceph
- Name four special investigations that an orthodontist would do? (2)
- Study models
- Radiographs OPT and lateral ceph
- Clinical photographs
- Sensibility test
30-year-old patient presents, worries about his class 3 incisor relationship.
3. Name four intra-oral features that this patient might have? (4)
- Proclined upper incisors
- Retroclined lower
- reduced OJ/Reversed OJ
- Reduced OB or possible AOB
- Anterior or posterior buccal crossbites (Due to smaller maxilla)
- Maxillary crowdind (due to smaller maxilla)
- Tendency for displacement on closure
- What systemic condition might the patient have if his mandible keeps growing? (1)
Acromegaly as the patient is 30 years old otherwise would be giantism
Acromegaly is a disorder that occurs when your body makes too much growth hormone (GH). Produced mainly in the pituitary gland, GH controls the physical growth of the body. In adults, too much of this hormone causes bones, cartilage, body organs, and other tissues to increase in size.
- What are the classes of AP relationship?
- Class I- maxilla 2-3mm in front of mandible (ANB 2-4°)
- Class II- maxilla more than 2-3mm in front of mandible (ANB> 4°)
- Class III- mandible in front of maxilla (ANB<2°)
Describe a class 3 incisor relationship?
When the lower incisors meet anterior to the cingulum plateu of the upper incisors
The OJ is reduced or reversed
- How is a class III malocclusion managed?
- Accept
- Intercept early with URA correction of the incisor relationship and crossbite
- Growth modifcation with a functional (reveresed twin block or Frankel lll) chin cup, head gear with RME to reduce and redirect mandibular growth and encourage maxillary growth and then fixed appliance
- Camoflague - accept underlying skeletal pattern and correct incisor relationship
- Surgery and fixed appliance for functional, speech, mastication or aesthetic concerns
Digit Sucking-
1. Give 4 intra-oral signs of thumb sucking/ non nutritive sucking habit?
- Proclination of the ULS
- Retroclination of the LLS
- Small Maxilla Posterior crossbite
- Localised anterior OB or incomplete OB
- Explain the effects of prolonged digit sucking habit on posterior dentition?
The thumb or finger is in the mouth and forces the tongue down. This results in an inbalance of force between the cheek muscles (buccinator) and the tongue. Causing the maxilla to be more narrow and this results in a posterior crossbite
- Give 4 methods of stopping a digit sucking habit?
- Positive reinforcement
- Non-appliance home cessation/ deterrents- plaster on fingers, preventative nail varnish, gloves, cellotape
- Removable habit break appliance
- Fixed appliance with anterior rake habit breaker (quad helix)
- What additions can be made to a URA to break the digit sucking habit?
- Deterrent rake
- Hawley retainer thumb appliance
- Palatal crib
- Bluegrass appliance
Patient with a NNSH presents with Class 2 Div 1 incisors and increased OJ.
1. What are 4 intra-oral sings of thumb sucking?
- Proclined upper incisors
- Retroclined lower incisors
- Small maxilla so posterior crossbite
- AOB or reduced OB
- What is the BSI incisor classification of Class 2 Div 1?
When the lower incisors meet below the upper incisor cingulum plateu.
Then the upper incisors are of average or proclined
Resulting in an increased OJ
- Functional appliance was used and successfully reduced the OJ. Give 8 changes or ways it did this.
- Mandible postured forward from its normal rest position
- Skeletal changes- facial musculature stretched (acts to pull upper dentition back) which generates forces transmitted to the teeth and alveolus and acts to restricts maxillary growth, meanwhile mandibular growth is encouraged as condyle are distracted and so encouraged to remodel which encourages mandibular growth, glenoid fossa also remodels (new floor of glenoid fossa formed) to grow forwards
- Dental changes- teeth held in edge to edge position, lower incisors are tipped forward (proclined) and lower molars mesialised by action of the lower block and musculature forces, upper incisors are tipped backwards (retroclined) and upper molars distalised by the action of the upper block and musculature forces
- Also disengages the occlusion
- Must be worn all the time
Cleft Lip & Palate-
1. What is the incidence of cleft lip and palate in the UK?
1 in 700 live births
- What are the general health implications of CLP?
Difficulties with
- Speech (air escapes during certain sounds hypernasality)
- Mastication
- aesthetics
- Hearing problems (problems with ear development)
- Potential airway blockage/ respiratory problems
- Often assocaited with other anomalies such as cardiac anomalies
- Increased risk of infection due to connection with nasal and oral cavity
What are the dental features for CLP
- Missing teeth (hypodontia)
- Sizes of teeth (mircodontia)
- Supernumeraries
- Ectopic position
- Hypoplastic
- Crowding due to the small maxilla
- Impacted teeth
- Class 3 growth pattern
- Outline 5 treatment stages for CLP patient?
- Lip closure at 3 months
- Palatal closure at 9 months
- Bone graft 8-10years
- Definative ortho 12-15years
- Revision Surgery 18-20 years
Name 5 members of the CLP MDT?
- Clef surgeon MAXFAX surgeon
- ENT
- Clef nurse
- Orthodontist * Dental team- paediatric dentist, orthodontist and orthodontic therapist, restorative dentist, oral surgeon, dental therapist
- Speech therapist
- Clinical pyschologist
Orthodontic Complications-
1. What are the common complications of orthodontics? and how is each one managed?
- Decalcification (Hard to manage once happens, so prevention is the best. Good OH, give dietary advice on sugar reduction and use of sugar free gum, encourage fluoride exposure via toothpaste, mouthwash and duraphat varnish)
- Relapse ( patients are given a retainer to retain the position of the teeth and prevent relapse to malocclusion. This can be a bonded fixed retainer or removable thermoplastic)
- Root resorption (Explain to the patient inevitable consequence of tooth movement but generally minimal and only 1-2mm over 2 years for FA. increased risk with high force of movement (hence avoid excessive orthodontic forces), previous trauma or blunt, short or pipetted root form (radiograph before to warn patient if risk increased as a result of this)
- Gingival recession (Adult patients should be made aware this a normal and somewhat Unpredicatbel risk, can be exacerbated by poor OH so ensure patient is aware of importance of good OH and give appropriate instruction on how to achieve this, also make patients aware this is exacerbate in cases of harsh toothbrushing or thin biotype)
Give 3 other linked complications of ortho tx?
Apart from root resopriton, relapse, decalcification, gingival recession
- Loss of vitality
- Soft tissue trauma
- Loss of periodontal support
- Enamel fracture
- Failed tx
Lateral Cephalometry-
1. In the lateral cephalometry- what are the SNA, SNB and ANB?
SNA - is the angle between the cranial base and the maxilla in an AP relationship (angle between mid-point of sella tursica, nasion and deepest concavity anteriorly on the maxillary alveolus)
SNB - is the nagle between the cranial base and the mandible in a AP relationship (angle between mid-point of sella tursica, nasion and deepest concavity anteriorly on the mandibular symphysis)
ANB - Is the difference between the maxilla and the mandible
- What are the average values for a Caucasian? on a lateral ceph.
SNA - 81 +/- 3
SNB - 78 +/- 3
ANB - 3+/-2
WHat is the average FMPA angle?
- 27 +/- 4°
- What is average incisors inclination?
- Upper- 109 +/- 6°
- Lower- 93 +/- 6°
- What is ANB for Class II and Class III patients?
- Class II- >4°
- Class III- <2°
Give the average value for LAFH and interincisal angle for lateral ceph?
LAFH - 55%
Interincisal angle - 135 degrees
Diastema-
1. Give 4 reasons for a diastema?
-Hypodontia (congential missing 2’s)
- Supernumerary Midline - tuberculate mesiodens
- Developmental
- Prominent/low frenum
- Pathological causes
- Generalised Spacing
- Proclined uppers
- How are diastemas managed?
- Accept and monitor
- Generally tx determined by the cause of the diastema
- Possible surgical removal of the supernumerary
- Early closure if severe and child is concerned - central may be pulled together and a bonded retainer used to prevent relapse (then if missing laterals these can be replaced)
- Fraenectomy may be indication if prominent frenum
- For proclined uppers URA to tip back
- For generalised spacing then ortho FA
- Pathology should be dealt with by oral surgery or oral medicine or MAXFAX
- Bonded retainer will always be required following tx as prone to relapse
- How is a posterior crossbite managed and write a prescription?
- URA with mid palatal screw
Please construct a URA to expand the upper arch
A - mid palatal screw (screw turned 1/2 a turn a week)
R - Adams clasp on 6’s 0.7mm HSSW and on URd and ULd 0.6mm HSSW
A - check
B - self cure PMMA with Posterior bite plane
How else can you manage a Posterior crossbite? apart from URA mid palatal screw
- Quadhelix with bands on the 6’s
- Rapid maxillary expansion appliance
- What teeth are most commonly infraoccluded?
lower ds (8-14%)
- How will they appear clinically and radiographically? Infra-occluded teeth
Clinically
- Appear submerged
- When tap have a dull precussion note
- No mobility
Radiographically
- blurred or absent PDL (ERR?)
- What are your treatment options for a infra occluded tooth?
Check if their is a permenant successor
* If permanent successor is present- monitor and observe for 1 year as generally exfoliate normally, consider extraction only if contact points going sub-gingival or root formation of successor is near completion
* If permanent successor is absent- retain if in good condition and either place only or build up to occlusal level with composite, extract when only 1mm of crown showing (to avoid going sub gingivally) or when patient can no longer effectively clean it and plan space management (either leave with gap as non-aesthetic tooth or replace with bridge etc)
- What percentage of 6-year-olds, 11-year-olds and 18-year-olds have diastema?
6 year olds - 98%
11 YO - 49%
18 YO - 7%
- What factors determine the management of infra-occluded teeth?
- Presence of successor
- Prognosis of the tooth
- OH levels of the patient
- Patients wishes
- Degree of infra-occlusion
Fixed Appliances-
1. Name 4 component of fixed appliances?
- Bracket
- Ligature
- Wire
- Bands
- Anchorage components
- Force generating components
- How does tooth movement work in terms of FA?
- When an external force is applied to a tooth, The PDL mediates remodelling of the bone around the tooth which allows the tooth to move(NB. Ankylosed teeth will not move)
- In orthodontics, forces applied casue recruitment and activation of osteoclasts and osteoblasts which allow bone remodelling
- There are three proposed mechanisms for how this works at a cellular level. Differential pressure theory, pizo-electric theory and mechano-chemical theory.
- The exact mechanisms depends on the appliance and the type of tooth movement
- FA works mainly by bodily movements
- Bodily movements involved frontal resorption, in response to light forces applied by appliance there is hyperaemia within the PDL and recruitment of osteoclasts and osteblasts. On the pressure side (direction in which the tooth is moving) there is resorption of the lamina dure and bone via osteoclasts (this is known as frontal resorption) while on the tension side (direction away from which the tooth is moving) there is apposition of osteoid via osteoblasts, this results in complete remodelling of the socket and movement of the tooth.
N.B Osteoclasts cannot tell what is bone and what is cementum hence cementum will also be resorbed hence all patients will get warned of the risk of root resorption. However cementum is much more resistant to resorption than bone hence the normally small degree of resorption
- What are the treatment options after extraction of retained C?
- Monitor and seee if canine spawntaneously erupts on its own
- Closed exposure (raise a flap, remove bone covering and attach gold chain to ectopic tooth, replace flap and wait for the tooth to erupt into line)
- Open exposure (Raise flap, remove bone and expose tooth, reposition flap apically (if buccally) and either wait for tooth to move down or attach ortho appliance to help pull down.
- Transposition
- Surgical Ex of canine
