Ortho Flashcards
What to check pre examination
- Presenting compliant
- Patient details and who they are with
- MH
- DH: trauma, previous extractions/restoration, digit sucking, previous tx
- Previous history
- Family/social history: skeletal 3
What is incisal display
- At rest 3-4mm male, 4-5mm female
- Smiling: up to 2mm gingivae
What is incisor inclination
- Upper 109 degrees
- Lower 93 degrees
Why should the Frankfort plane be parallel to the floor
- Reproducible
- Standardized
- Used in cephalometry
What is skeletal 2 AP
- 2mm behind the line (zero meridian line)
- Mandibular retrognathia
What is skeletal 3
- Infront of line
- Maxillary hypoplasia ?
- Paranasal hollowing
What is the LAFH averages of male and female
- 16y male 72mm
- Female 68mm
What is microdonita and incidence
- Teeth smaller than normal
- 1.5% to 2%
What is crowding
- Contact arch displacement (d in IOTN)
- 1-4mm mild
- 5-7mm moderate
- > 8mm severe
- Spacing: generalised or localised
What to check when teeth in occlusion
- Incisor relationship
- Overjet
- Overbite
- Molar and canine relationship
- Crossbite/ displacement
- Centrelines
What are the incisor relationships
- Class 1
- Class 2 div 1: overjet is increased and usually incisors proclined
- Class 2 div 2: retroclined
- Class 3: overjet reduced or reversed
What are the molar relationships
- Mesiobuccal cusp of upper
- Mid buccal grove of lower
- Canine upper occlude posterior to the lower
- Class 2: mesiobuccal cusp mesial to the mid buccal grove
IOTN
- Dental health component
- Aesthetic component
What is overbite
- Complete: traumatic/ non traumatic
- Incomplete: incisor overlap with no incisor contact
- F is IOTN
What is open bite
- Anterior open
- Lateral open
- E on IOTN
What is the definition of displacement
- Movement of mandible on closing from Centric relation (RCP) into centric occlusion as a result of occlusal interference
- When treatment planning take records in no displaced position as it is reproducible
- Cross bite: C, l (lingual)
What is the justification for panoramic
- Presence of teeth: unerupted and erupted
- Assess roots
- Check bone levels
- Other pathology: caries
- Check condyles
What are the aims of treatment
- Improve aesthetics and appearance
- Establish good occlusal result
- Good molar relationship
- Average overbite, overjet
- Relieve crowding
- Eliminate displacements/ crossbites
- Produce a stable occlusion
What are Andrews 6 keys
- Molar relationship
- Crown angulation
- Crown inclination
- Rotations
- Contact points
- Curve of spee: flat occlusal plane, no deeper than 1.5mm
What is average adult lip length
- 20mm female
- 22mm male
Effects of digit sucking
- Procline upper and retrocline lower
- Unilateral crossbite
- Anterior open bite
Tell me about hypodontia
- Developmental absence of one or more teeth (excluding 3rd molars)
- Mild/ mod/ severe (oligodontia: 6 or more, anodontia: all teeth)
- Aetiology: environment, genetic (MSX1 PAX9)
Tell me about supernumerary tooth
- Incidence = 3% Caucasian permanent dentition
- Primary <1%
- Maxilla: mandible 5:1
- Classification: supplemental, conical (peg shaped, mesiodens), tuberculate (barrel shaped), odontome (complex/compound)
Ectopic teeth
- Fail to erupt in correct position within the dental arch
- Canines commonly affected (maxillary canines 11-12 palpated 9, mandibular canines 9-10)
- Maxillary canine: 2%, mandibular canine: 0.35%
Effects of loss of primary teeth
- Crowding
- Ectopic eruption, impacted teeth
- Unfavourable molar relationship
- Centre-line shifts
- Consider space maintainers
Impaction numbers
- Upper central incisors (0.13%)
- Upper canines (2%)
- Second premolars (20%)
- First molars (0.75-6%)
- Third molars (25%)
Risks if teeth are unerupted due to impaction
- Root resorption
- Cyst formation
- Poor aesthetics
How to locate unerupted teeth
- Visual examination: bulges, angulation of lateral , colour
- Knowledge of eruption pattern
- Palpation (8-10), mobility of the baby tooth
Use of OPG
- Unerupted teeth
- Root position, shape, closure of apex
- Developing teeth - stage of development
- Condyles
- Bone support levels
- Pathology – cysts, supernumeraries, tumours,
- periapical radiolucent areas
advantages and disadvantages of OPG
- Advantages:
- Shows all the teeth
- Shows complete view of both jaws
- Objects closer or further away from beam will be magnified/diminished helping to localise position
- Disadvantages:
- Poor quality especially in midline
- Narrow focal trough – we do not always see the true picture
- Often require supplemental view to confirm details
Function of a space maintainer
- Maintain arch length and width preservation of leeway space
- Prevent over eruption
- Aesthetics
- Aid in the management if oral habits – digit sucking
- IDEAL: simple, passive, strong, cleansable
Types of space maintainer
- Unilateral: band and loop
- Bilateral: Transpalatal arch (prevents mesial drift of 6), lingual arch, URA(removable)
How much lee way space
- 2.5mm lower
- 1.5mm upper
Why might a primary tooth be retained
- Successor developmentally absent
- Successor ectopic
- Local abnormality (infra occlusion)
- Failure of permanent to resorb tooth
Infraocclusion
- Fails to erupt fully
- 8-14% in 6-11
- Trauma, absence of successor, ankylosis
- Mid, moderate, severe
Methods to increase arch length or create space
- Molar distal movement (headgear or TADs) / incisor forward movement
- Arch expansion (removable or fixed appliance)
- Interproximal enamel reduction
- Extraction
Tell me about growth
- Epigenetics
- Rate increase during puberty
- Female develop earlier
- Difficult to predict
Ideal properties of an index of treatment need
- Valid
- Reproducible
- Ease of use
- Acceptable
- Cheap
- Clinical audit and research
What are limitations of IOTN
- No account for skeletal and soft tissue
- Only dental factors
- No account for growth potential
- Not an index of treatment complexity
- Incentive to patient concerns/ demands
Extractions of first permanent molars
- Erupts 6-7, complete root at 9-10
- Problems: localised space, over eruption and tipping of adjacent
- Slightly crowded would have the best effect
Prevalence of each malocclusion
- Class 1: 67%
- Class 2 div 1: 15%
- Class 2 div 2 10%
- Class 3: 3%
Canine extraction considerations
- Try avoid as cornerstone and involved in canine guidance
- Can mask premolar if good contact, rotation through fixed appliance
What is the class 1 malocclusion
- Maybe be increased VD or dental problem
- Dentoalveolar disproportion: distalisation of molar using headgear, TADS, interproximal reduction, lee way space, extraction s
- Hypodontia: accept, camouflage, space closure or opening
- Supernumerary: extraction
- Variation in tooth size: macro/micro (composite build up) dens in dente, dilaceration
What is class 2 div 1 malocclusion
- Skeletal: mandibular retrognathia (80%), maxillary hyperplasia, vertical any
- Environmental: digit sucking,
- Dental: crowding
- Soft tissue: lower lip trap, lip incompetence
- Trauma incidence 5mm 22%, under 9mm 24%, 44% over 9mm
- Accept: mouthguard for trauma
- Growth modification: growing, mild to moderate, twin block (70% dental, 30% skeletal)
- Head gear: catch up growth of mandible, difficult compliance
- Camouflage: upper 4, lower 5s
- Orthognathic: growth complete, severe, decompensation before (appliances throughout the procedure)
Digit sucking habit effects
- Proclination of uppers and retroclination of lowers
- Increased overjet
- AOB
- Narrow upper arch, unilateral posterior cross bite
Tell me about class 2 div 2
- Skeletal: 2 or 1, Vertical reduced, progenia
- Soft tissue: strap lip, high lip line
- Soft tissue will have obtuse Nasio labial angle
- Dental: retroclination of uppers (2s might escape), increased IIA, traumatic overbite, crowding increased by retrocline uppers
- Accept: mouth guard for trauma
- Growth modification: convert to class 2 div 1 by Proclination of uppers (ura:ELSAA with T/Z spring and anterior bite block to allow over eruption of posterior teeth, twin block with procline spring, sectional fixed appliance)
- Camouflage: mild/moderate, upper 4s lower 5s, IIA must be corrected or relapse
- Orthognathic: same as class 2 div 1
- Usually required long term retention due to relapse
Tell me about class 3
- Genetic: cleft lip (maxilla less growth)
- Skeletal: maxillary hypoplasia, mandibular prognathism, vertical (can be any)
- Soft tissue: macroglossia (tongue pushes lls), not a big effect
- Skeletal pattern 3 (55% maxillary problem) or 1
- Soft tissue factors: increased sclera show, paranasal hollowing, obtuse NLA
- Dental factors: reduced overbite or anterior open bite, more crowding in upper dentition, microdontia/hypodontia causing narrow upper arch
- Masticatory problems, speech problems
- Accept: patient not concerned, OHI, acceptable aesthetics
- Early Interceptive treatment (pre 10): URA, good overbite, able to go edge to edge, bone loss trauma
- Growth medication (intermediate): headgear, rapid maxillary expansion, reverse twin block , not guaranteed treatment
- Camouflage: mild to moderate, edge to edge, good overbite
- Orthognathic surgery:
Tell me about ARAB
- Active component – t spring
- Retention – Adam’s clasps and c clasps
- Anchorage – baseplate and Adams
- Baseplate – cold cure acrylic – bite block incorporated
Fixed appliance
Problems associated with fixed appliances
- Demineralisation: poor OHI and diet , plaque score below 20% before treatment, can remove arch wire, plaque retentive factors
- Gingivitis and periodontal disease
- Root resorption: majority - minor around 1mm, 5% cases 5mm loss, Risks (history of trauma, treatment duration, apical movement, genetic)
- Pulpitis: transient in majority of patients, caution treating trauma teeth
- Soft tissue ulcers: brackets can use wax, no sharp ends of wire
- Inhalation: chest x ray
Maxillary incisors and impaction
- 7-8 central eruption (root formation completes around 11)
- On eruption there is midline diastema
- 0.13% in 5-12year olds: impacted maxillary central incisors
- Concerns: contra lateral over 6 months, lower incisors over 1 year (uppers unerupted), lateral erupt before central
- Radiograph: parallax with upper standard occlusal or CBCT
Reasons for maxillary central incisor impaction
- Early loss of primary centrals
- Trauma: e.g. scar tissue preventing eruption
- Macrodont: fusion of 2 teeth into one , not enough space
- Supernumerary tooth: tuberculate most common impaction causer
- Dilaceration: distortion or bend in the root of a tooth: idk how this affects
- Ankylosis: following trauma, fixed appliance on ankylosed tooth will not move
- Other: cysts, cleft lip
Treatment for unerupted central
- Remove obstruction
- Maintain space (URA)
- Monitor for 12months – 80% erupt
- Expose and bond if unerupted (closed if high, open if superficial)
- Over 10: straight to expose and bond
Maxillary canines and impaction
- F:M > 2:1
- 2% (85% palatal, 15% buccal), absent is 0.08%
- Corner stone of arch, canine guidance, erupts distally along the 2, long route of eruption, palpable at 9, late is 12-13
- Small lateral, missing laterals (increases incidence to 5%)
Radiograph and maxillary canine
- Prior to 10 little benefit, above 11 where 3s aren’t palpable
- Cbct or parallax (pa, USO)
Management of 3s
- Interceptive: extract c, need space for 3
- Surgical expose and bond: extract premolar if need space, closed and open technique
- Surgical repositioning (ankylosis risk), surgical removal
Prognosis of canine
Risks of aligning impacted canines
- Root resorption to adjacent teeth
- Loss of vitality
- Poor tissue contour at completion of treatment
- Increased pocket depths
- Canine root resorption
- Ankylosis
Define impaction
- Tooth that is prevented from erupting into its normal functional position by bone, tooth, fibrous tissue.
Functional appliances
- Use forces generated by the oral facial musculature to produce dental and skeletal changes. Force generated by stretching the facial muscles in a postured position
Considerations for class III treatment
-Ability to achieve edge to edge occlusion
-Ability to retain occlusion with a positive overbite
-Extent of displacement
-Extent of dento-alveolar decompensation
-Age of patient
-Cause of malocclusion (maxillary growth stops before mandibular growth)
-Is patient happy with facial profile