intro to ortho Flashcards
what is orthodontic
- speciality of dentistry concerned with:
- diagnosis and development of teeth, face and jaws
- diagnosis, prevention and correction of dental and facial irregularities
what does orthodontic assessment include
- systematic evaluation of the face and skeletal based in 3D
what do the position of the teeth rely a lot on
- size, shape and relative position of the underlying bones
what is the maxilla attached to
- anterior cranial base
what are teeth invested in
- alveolar bone
what does the mandible articulate with
- posterior cranial base
how do you determine a skeletal relationship
- look at the basal bones
- relationship between two basal bones gives the idea of the skeletal relationship
what are the basal bones
- innermost curvature of the upper lip in maxilla
- innermost curvature of lower lip in mandible
what orientation does the head need to be to assess skeletal relationship
- Frankfurt plane needs to be horizontal to the floor
- top of ear lobe (prion) and the orbitalae
what is a class 1 skeletal relationship
- mandible is 2-3mm behind the maxilla
- expect them to have a normal overjet and overbite and teeth should look ok
what is a class 2 skeletal relationship
- mandible is more than 2-3mm behind maxilla
- expect teeth to have an overjet
what is mandibular hypoplasia
- mandible is smaller than it should be
what is mandibular retrognathia
- mandible is right size but further back in the glenoid fossa
what is a class 3 skeletal relationshp
- mandible is less than 2-3mm behind maxilla
- can get a reverse overjet
what is hemimandibular hypertrophy
- facial asymmetry
- tends to happen mainly in females in late teens and early 20’s
- slowly progressive
- don’t know aetiology
- condylar cartilage is still growing and producing bone, and ramus is as well but only on one side
- secondary bowing of ramus on other side and lack of eruption of maxillary teeth on one side
- complex
what is hemifacial microsomia
- results in failure of development of condyle ramus and body
- malformed ear and conductive deafness on that side
- doesn’t have any bone or muscle or nerves to grow on that side
how do you treat a hemifacial microsomia
- costal-chondral graft
- take a piece of rib and strap to ramus
- works ok in 1/3 of cases, overgrow in 1/3 and nothin happens in 1/3 of cases
what are lateral cephalograms for
- help define where faults lie
- trace to help in diagnosis and planning of these patients
- only take these if you think there is a skeletal problem
- only do if skeletal classification 2 or 3
what are some growth modification techniques to promote/restrict growth in children
- functional appliances = grow mandible
- headgear = restrict maxillary growth, rarely use
- reverse pull facemask and RME = promote maxillary growth
what can be done for treating adults who have skeletal discrepancies
- orthognathic surgery
- single jaw or bimaxillary procedures
how does functional appliances work
- twin block
- two separate appliances, one on top jaw and one on bottom
- wore for around 9 months full time
how do you do a bilateral sagittal split orthognathic surgery
- split on outside halfway along and inside behind the nerve and connects the two cuts
- slide mandible forwards or backwards so very versatile
- difficulty is that the area where we cut is close to the nerve so could end up with permanent nerve damage
how do you do a le fort 1 orthagnathic surgery
- chop teeth off maxillary base and move forward and up into predetermined position
who is in the orthodontist team
- orthodontist
- maxillofacial surgeon
- clinical psychologist
- maxillofacial technician
- speech therapist
- GDP
how common is cleft lip and palate
- 1 in 700 live births
- common
why do cleft lips and palates happen
- don’t understand why
- multifactorial
- lifelong condition
- smoking, genetics, drinking are all factors which may not help
what is the team for cleft lips and palates
- orthodontist
- cleft surgeon
- ENT
- speech therapy
- max-fax surgeon
- plastic surgeon
- dental practitioner
how can you treat cleft lip and/or palate
- at about age 12, have an alveolar bone graft
- take bone from hip and pack in to allow canine to come through
what can go wrong in development
- lots
- increased overjet
- deep overbite
- anterior cross bite
- posterior cross bite
- retained deciduous teeth
- early loss of deciduous teeth
- ectopic teeth
- impacted first molars
- crowding
- spacing
- trauma
- habits
- anterior open bite
- lateral open bite
- ankylosis of deciduous teeth
- cysts
- supernumeraries
- dental asymmetries
what do you do for a submerging deciduous molar
- can watch tooth till it gets to 1mm of gum, then have to think about taking it out
- if it disappears then need to go in surgically and remove it so other tooth can erupt
- quite tricky to treat
what can you do for tuberculate supernumeraries
- centrals should always erupt before laterals
- should think taking a radiograph as these laterals appear
- teeth are in the way
- take out a’s and supernumerary and keep space open and fingers crossed centrals will come in
- if anything ever goes wrong with eruption sequence thank about taking a radiograph
what are some occlusal and dental anomalies
- crowding
- spacing
- increased overjet
- reverse overjet
- anterior open bite
- deep bite
- hypodontia
- supernumeraries
- anterior cross bite
- posterior cross bite
- ectopic teeth
- delayed dental development
- macrodont
what are the two types of supernumerary teeth
- tuberculate
- conical
which of the two supernumerary teeth types will erupt
- tuberculate never erupt
- conical sometimes erupt
which type of cross bite is easiest to treat
- anterior cross bite can be treated in couple months
- posterior cross bite needs 9 months to be treated
what stages help in orthodontic diagnosis
- systematic assessment of teeth, face and jaws
- study models
- radiographs
- photographs
- sensibility tests
- cone beam CT scan
what is included in a systematic assessment for ortho diagnosis
- facial anomalies, asymmetries
- skeletal relationship
= how jaws related to each other
= how jaws related to skull base - teeth in each arch separately
- occlusion
why are photographs good for ortho diagnosis
- can record the start of treatment and end
- see the improvement
what are the aims of orthodontic treatment
- provide a stable, functional and aesthetic occlusion
- if missing teeth, then teeth they do have are rarely in right position
what are different types of appliances
- removable
- functional
- fixed
- others = aligners, Invisalign, headgear, temporary anchorage devices
what are removable appliances used for
- tip teeth, open bites, maintain space
- good at reducing overbites in growing patients
- start with this for a lots of patients
what are functional appliances used for
- modify jaw growth
- trying to grow lower jaw and tip teeth in better position
what are fixed appliances for
- true 3-dimensional control of tooth position
- can correct tooth position in all 3 directions
what are the benefits of orthodontic treatment
- improve function
- improve appearance
- improve dental health
- reduce risk of trauma
- facilitate other dental treatment
how can ortho improve function
- can make it easier for patient to eat
how can ortho improve function
- make teeth easier to clean
how can ortho reduce risk of trauma
- if teeth were sticking out they are at risk
what are the 3 main risks of ortho
- decalcification around brackets from not brushing well
- relapse = everyone gets it to some extent, but can be worse if don’t follow guidelines
- root resorption = 1in 500 get a lot
what are some other risks of ortho
- pain, discomfort
- soft tissue trauma
- failure to complete treatment
- loss of tooth vitality
- inhale or swallow small components
- candida infections
how many ortho patients are adults
- around 30%
what is ankylosis
- teeth are fused together
how are aligners and invisalign used
- patient changes every couple weeks
what is used to assess the antero-posterior skeletal pattern
- palpation of skeletal bases
what is used to assess the vertical skeletal pattern clinically
- Frankfort Mandibular Plane Angle
- FMPA
which two soft tissue landmarks are sued to construct the Frankfort plane
- porion and orbitale
which two soft tissue landmarks are used to construct the mandibular plane
- gonion and menton
what 3 dimensions should skeletal relationships be assessed
- antero-posterior, vertical and transverse
what maxillary tooth is more commonly ectopic than incisor
- canine
what does ideal occlusion mean
- term given to dentition where teeth are in optimum anatomical position
what does malocclusion mean
- term given to describe dental anomalies and occlusal traits that represent a deviation from the ideal occlusion
how common is malocclusion in adolescents
- moderate-severe is around 40-50%
how can ortho treatment help speecj
- won’t significantly change speech
- but if someone can’t get contact between incisors anteriorly, may contribute to a lisp
what is another name for lisp
- interdental stigmatism
how much root resorption is normal after ortho
- over a 2-year fixed appliance period, 1mm or root resorption will happen
how can ortho lead to loss of periodontal support
- increase in gingival inflammation is commonly seen following placement of appliance
how can ortho cause soft tissue damage
- ulceration can occur as a result of direct trauma
- allergic reactions are rare but have happened = nickel and latex
what are operator factors that could lead to failure of ortho
- errors of diagnosis
- errors of treatment planning
- anchorage loss
- technique errors
- poor communication
- inadequate experience
what are patient factors than can lead to failure of ortho treatment
- poor OH
- failure to wear appliance
- repeated appliance breakage
- failure to attend appointments
- unexpected unfavourable growth
what is a functional occlusion
- free of interference to smooth gliding movements of the mandible with no pathology
what are the causes of malocclusion
- skeletal pattern
- soft tissues
- dental factors
what is Angle’s Classification
- molar relationship
what is class 1 Angle’s
- mesiobuccal cusp of upper first molar occludes with mesiobuccal groove of lower first molar
- normal
what is class 2 Angles
- mesiobuccal cusp of lower first molar occludes distal to class 1 position
what is class 3 angles
- mesiobuccal cusp of lower first molar occludes mesial to class 1 position
what is index of orthodontic treatment need (IOTN)
- has two elements
= dental health component
= aesthetic component - determine impact of malocclusion on health and mental well-being
what does the dental component of IOTN includes-
- single worst feature of malocclusion is noted and categorised
- grade 1 (no need) - grade 5 (very great need)
- or look consecutively at all these features = missing teeth, overjet, crossfire, displacement, overbite
what does the aesthetic component of IOTN include
- 10 photographs which are graded from score 1 (best) to score 10 (worst)
- scores are categorised into need for treatment
- score 1 and 2 = no
- score 3 and 4 = slight
- score 5 6 ad 7 = moderate
- score 8 9 or 10 = definite
what is peer assessment rating (PAR) used for
- measure success of treatment
what is index of complexity, outcome and need (ICON)
- incorporates both IOTN and PAR
what are Andrew’s 6 keys
- correct molar relationship
- correct crown angulation -
- correct crown inclination
- no rotations
- no spaces
- flat occlusal plane
what is the correct molar relationship
- mesiobuccal cusp of upper first molar occludes with groove between mesiobuccal and middle buccal cusp of lower first molar
- distobuccal cusp of upper first molar contacts mesiobuccal cusp of lower second molar
what is correct crown angulation
- all tooth crown are angulated mesially
what is correct crown inclination
- incisors are inclined towards the buccal or labial surface
- buccal segment teeth are inclined lingually
- in the lower buccal segments this is progressive
what is Andrew’s key 1
- molar relationship
- distal surface of distal marginal ridge of upper first permanent molar occludes with mesial surface of mesial marginal ridge of lower second molar
- mesiobuccal cusp of upper first permanent molar falls within groove between mesial and middle cusps of lower first permanent molar
what is Andrew’s key 2
- crown angulation or mesiodistal tip
- gingival portion of long axis of each tooth crown is distal to the occlusal potion of that axis
- degree of tip varies with each tooth type
what is Andrew’s key 3
- crown inclination or labiolingual torque
- for upper incisors the occlusal portion of the crowns labial surface is labial to gingival portion
- in all other crowns, occlusal portion of the labial or buccal surface is lingual to the gingival portion
what is Andrew’s key 4
- rotations
- there should be an absence of any tooth rotations within the dental arches
what is Andrew’s key 5
- spacing
- there should be an absence of any spacing within the dental arches
what is Andrew’s key 6
- occlusal plane
- should be flat
what is class 1 occlusion
- position of dental arches is normal, with first molars in normal occlusion
what is class 2 division 1 occlusion
- relations of dental arches are abnormal, with all mandibular teeth occluding distal to normal
- upper incisors are protruding
what is class 2 division 2 occlusion
- relations of dental arches are abnormal, with first molars in normal occlusion
- upper incisors are lingually inclined
what is class 3 occlusion
- relations of the dental arches are also abnormal, with all mandibular teeth occluding mesial to normal
what is retruded contact position (RCP) or centric relation (CR)
- gnathological term that describes position of mandible in relation to maxilla with condyles in most stable and reproducible position
what is intercuspal position (ICP) or centric occlusion (CO)
- occlusion that occurs with the teeth in a position of maximum intercuspation
what is canine guidance
- present when contact is maintained on the working side canine teeth during lateral excursion of mandible
what is group function
- present when contacts are maintained between several teeth on the working side during lateral excursion of mandible
what is canine class 1
- the maxillary permanent canine should occlude directly in the embrasure between mandibular canine and first premolar
what is canine class 2
- maxillary permanent canine occludes in front of the embrasure between mandibular canine and first premolar
what is canine class 3
- maxillary permanent canine occludes behind the embrasure between mandibular canine and first premolar
what is incisor class 1
- lower incisor tips occlude or lie below the cingulum plateau of upper incisors
what is incisor class 2 division 1
- the lower incisor tips occlude or lie posterior to the cingulum plateau of upper incisors
- overjet is increased with upright or proclined upper incisors
what is incisor class 2 division 2
- lower incisor tips occlude or lie posterior to cingulum plateau of upper incisors
- upper incisors are retro-inclined, with a normal or occasionally increased overjet
what is incisor class 3
- the lower incisor tips occlude or lie anterior to the cingulum plateau of upper incisors
what can cause malocclusion
- genetics
- lip trap = lower lip rests behind upper incisor
- sucking habits
- pathology = childhood fractures, juvenile rheumatoid arthritis, excess GH, PD
- early loss of primary teeth
