Orthodontics Flashcards
1-99 L1: examine ortho patient 100-120: Patient History Taking 121-127: Extra Oral Assessment 143-164: Canines 165-202: Cephalometrics 203-223: IOTN
The relative position of the maxilla and mandible, termed the skeletal pattern, has a large influence on the relationship of the maxillary and mandibular dentition. The skeletal pattern should be assessed in three dimensions:
- Anteroposterior
- Vertical
- Transverse (asymmetry)
What is the aim of recording the anteroposterior dimension?
The aim is to relate the AP position of the mandible to the maxilla and the relationship of these bones to the cranial base
Assessment of the position of each jaw relative to the cranial base gives an indication of which jaw may be contributing to a?
malocclusion
An assessment of the severity of the anteroposterior dimension discrepancy will help to guide whether treatment can be provided with?
orthodontics alone or if a combination approach that also involves orthognathic surgery
Why is it important to assess the patient in the natural head position?
It is important to assess the patient in the natural head position, which is a standardised reproducible head orientation, as the tilt of the head can greatly influence the interpretation of the skeletal pattern.
To achieve this, the patient should be sitting upright, relaxed, and looking straight ahead at a distant point at eye level and the teeth should be lightly in occlusion.
The most anterior part of the maxilla and the mandible can be palpated in the midline through the base of the lips. The relationship of the mandible relative to the maxilla can be classified as.
- Class I – when the mandible lies 2–3 mm posterior to the maxilla. The profile is straight.
- Class II – when the mandible is retrusive relative to the maxilla. The profile is convex. The discrepancy should also be classified as mild, moderate or severe.
- Class III – when the maxilla is retrusive relative to the mandible. The profile is concave. The discrepancy should also be classified as mild, moderate or severe.
Image a,b,c indicate what type of anteroposterior classification?
A = class 1
B = class 2
C = class 3
To determine the position of the mandible and maxilla relative to the cranial base, one imagines a vertical line drawn through soft tissue nasion in the natural head position. This line is termed the?
zero meridian 1,2 and represents the anterior limit of the cranial base.
What is the soft tissue nasion?
is the midpoint on the soft tissue contour of the base of the nasal root at the level of the frontonasal suture (marked as N)
The anterior limit of the base of the upper lip (soft tissue A-point) should lie how many mm ahead and the base of the lower lip?
2-3 mm
When making this assessment (anteroposterior relationship), it is important to remember that ethnic variation exits in normal lower face protrusion. The face progressively becomes less protrusive as follows:
African Caribbean > Asian > whites of northern European ancestry.
The term used when both jaws are protrusive is bimaxillary protrusion, which is a common feature in which ethnicity?
African Caribbeans
The vertical skeletal dimension can influence the degree of vertical incisor overlap, lip competency and overall facial aesthetics. There are two methods in which the vertical dimension should be assessed:
- Lower anterior face height (LAFH) proportion
- Frankfort-mandibular planes (FMPA)
Vertically in the frontal view, the face can be split into thirds. What are they?
- Lower anterior face height (LAFH) also known as the Menton
- Middle face height also known as Glabella (should be approx. equal to the LAFH)
- Trichion
The FMPA is assessed in the profile view and gives an indication of the relationship between the LAFH and?
Posterior face height (ramus height)
The Frankfort horizontal plane is measured from where?
The plane connects the lowest point of the orbit and the tragus.
Where is the mandibular plane?
Is the plane that starts at the menton to the angle of mandible
The FMPA is assessed in the profile view and gives an indication of the relationship between the LAFH and posterior face height (i.e. ramus height). It is normal when the line of the mandibular plane and Frankfort plane intersect in the?
occipital region.
If the point intersection (Frankfort plane and mandibular plane) is anterior to the occiput, the vertical dimension Is usually?
Increased
If the point intersection (Frankfort plane and mandibular plane) is posterior to the occiput, the vertical dimension Is usually?
Decreased
What is occiput?
The back of the head
The two components of the transverse dimension that should be assessed are:
- Facial symmetry
- Arch width
It is quite common to find asymmetries in the face, but those that affect the mandible and maxilla are particularly important when planning orthodontic treatment.
The symmetry of facial structures can be assessed by constructing the facial midline between soft tissue nasion and the middle part of the upper lip at the vermillion border. Which other point should be coincident with this line?
The chin point should be coincident with this line
The relative width of the upper and lower arches affects the transverse relationship of the?
Teeth
Which of the dental arches should be slightly wider that the other?
The maxilla
What is a cross bite?
A crossbite is a type of malocclusion, or misalignment of teeth, where upper teeth fit inside of lower teeth. This misalignment can affect a single tooth or groups of teeth, involving the front teeth, back teeth or both.
What are the 5 main types of cross bites?
- Anterior crossbite
- Posterior crossbite
- Single tooth crossbite
- Unilateral crossbite
- Bilateral crossbite
What is anterior crossbite?
In this condition, one or more upper front teeth are positioned behind the lower front teeth, according to the American Association of Orthodontists. This condition is distinct from an underbite, in which all of the top teeth or jaw are positioned behind the bottom teeth.
What is a posterior crossbite?
In a normal bite, the upper back teeth sit slightly outside of lower back teeth. However, in a posterior crossbite, it’s the opposite—the upper back teeth sit inside the lower back teeth
What is a bilateral crossbite?
A bilateral crossbite affects the back teeth of both sides of your jaws. In this condition, the top back teeth are situated inside of the bottom back teeth
What is the most common reason for a bilateral crossbite?
Often result of the upper jaw being underdeveloped
What is unilateral posterior crossbite?
A unilateral crossbite involves misalignment on only one side of your mouth. A unilateral posterior crossbite is where only one side of the mouth has the top back teeth sitting inside the bottom back teeth
The maxilla and mandible are represented by which landmarks when using the zero-meridian line?
The maxilla is represented by the upper lip and the mandible by the chin point.
If the chin or lip is ahead of the zero-meridian line or a combination of both, what would be the skeletal pattern classification of the patient?
Class 3 prognathic
If the chin or lip is behind of the zero-meridian line or a combination of both, what would be the skeletal pattern classification of the patient?
Class 2 retrognathic
What type curvatures would you expect to find in the following skeletal patterns:
1. Class 1
2. Class 2
3. Class 3
- Class 1 – straight curvature
- Class 2 – convex curvature
- Class 3 – concave curvature
For what purpose would do a bi-digital palpation?
Do determine the skeletal pattern
Where is point A and B when you go for a bi-digital palpation?
Point A sits at the deepest curvature between the sub nasal and the upper lips. Point B sits at the deepest part between your lower lip and chin.
How can soft tissues affect the classification of skeletal pattern when you do a extraoral bi-digital palpation?
Different patients have different level of thickness of soft tissue, which could camouflage the underlying skeletal pattern, thus it might be better to do the bi-digital palpation intra-orally.
When doing a bi-digital palpation what would the following results indicate?
- Straight arm
- Arm moves down
- Arm moves up
- Straight arm – class 1 skeletal patten
- Arm moves down – class 2 skeletal pattern
- Arm moves up – class 3 skeletal pattern
How would you position yourself to assess the vertical skeletal pattern on a patient?
In front of them
What is the name of the point on your forehead (prominence between your eyebrows), also used to place the zero-meridian line?
Glabella
What is the name of the point on your chin button?
Menton
What is the name of the point just under the nose?
Subnasle
What position does the head start and end?
Starts at the hairline and ends at the menton
The face can be divided in to how many sections?
3
1- Upper 1/3rd
2- Middle 1/3rd
3- Lower 1/3rd
Where does the upper 1/3rd start and end?
Starts at the hairline and ends at the glabella
Where does the middle 1/3rd start and end?
Starts at the glabella and ends at the subnasle
Where does the lower 1/3rd start and end?
Starts at subnasle and ends at the menton
What is the desired measurement for the 3 sections of the face?
All 1/3rd sections to be equal
The LFH measurement can vary depending on what?
Different position of teeth and jaw
The Lower face Height can be further divided into upper 1/3rd and lower 1/3rd. what are the landmarks for this further division?
1- LFH – upper 1/3rd = subnasle to upper lip
2- LFH – lower 2/3rd = upper lip to menton
What does FMPA stand for
= Frankfort Mandibular Plane Angle
what is the average FMPA angle meant to be?
25 degrees
If the Mandibular Plane and the Frankfort plane are almost parallel and have a low FMPA angle, what does it mean in reference to the intersection point for the FMPA and the growth of the mandible.
1- The intersection of the FMPA will pass the occiput
2- The low angle indicates horizontal growth of the mandible, with low/no vertical growth
The transverse skeletal pattern can be assessed using lines known as?
Facial fifths marking the canthus of the eye and ears.
the landmark where the eye lids meet is known as the?
canthus of the eye
In a well-proportioned face what would you expect the facial fifths measurements to be?
Equal
Assessment of the lip in relation to the teeth is done at two points:
lips at rest and lips whilst smiling
During rest of the lips what two things should you see?
Lips should touch each other or at most should show 1-2 upper teeth.
During rest if the lips are touching each other or maximum two teeth are showing we would refer to this as?
Competent lip
If the lips are apart during rest and is showing more than 4mm of teeth, what would we refer to this as?
Incompetent lip
What are the most common reasons for an incompetent lip?
Proclined or protruded front teeth
On smile for males how much of the incisors would you expect to see?
Full length of the incisor
On smile for females how much of the incisors would you expect to see?
Full length of the incisors plus 1-2mm of the gingiva is considered a youth full smile
Sometime in females, there is an increased exposure of the gingiva known as gummy smile, what is the common reason for this?
Increase vertical growth of the maxilla or short length of the upper lip
What is the condition of oral hygiene before starting any orthodontic treatment?
Immaculate oral hygiene
The extraction of healthy teeth is common during orthodontic treatment, what are the most common healthy teeth to be extracted and why?
The premolars are the most common tooth to be extracted to create space
It is common to see patients with mix dentition, so it is important to be able to differentiate between primary and secondary tooth. What can you do to help aid in deciding if it is primary or secondary?
- If the tooths presence co-relates with the patient’s age
- Check to see if it is firm or mobile
From what age onwards is it important to assess the position of the maxillary canines?
10 years onwards. Should be palpable above the deciduous canines
If you cannot palpate the maxillary canines at age 10 years what would, you do to locate them?
Take an x-ray to locate their position
For the orthodontic assessment of the lower labial segment includes which teeth?
3-3
What is the inclination of the incisors?
The crown inclination, representing an angle formed by the clinical crown axis and a line which bears 90 degrees to the occlusal plane, reflects the labiolingual or buccolingual inclination of the long axis of the crown
hat are the 4 things that are assessed for the lower labial segment? Inclination/aligned/crowded/spaced
Inclination/aligned/crowded/spaced
How would you describe this image?
Bi-maxillary proclination
how would you describe this imagine in reference to inclination?
Average inclination
how would you describe this imagine in reference to inclination?
Proclined incisor inclination
how would you describe this imagine in reference to inclination?
Retroclined incisor inclination
What are the severity parameters for crowding?
- 0-4 mm – mild
- 4-8 mm – moderate
- > 8 mm – severe
What type of analysis is required when the primary molars and canines are still present?
Mix dentition analysis
What is the desired space required for the maxilla and mandible for the eruption of the molars and premolars?
21mm both side maxilla and 22mm both side for the mandible.
When the mesio-buccal cusp U6 sits on the buccal groove L6 what classification is it?
Class 1
When the mesio-buccal cusp U6 sits on the disto-buccal cusp L6 what classification is it?
Class 3
When the disto-buccal cusp U6 sits on the buccal groove L6 what classification is it?
Class 2
What is the reference point to determine the incisor classification?
The cingulum of the upper central incisor, the positioning of the central incisor ahead of the lower incisor
What are the following classifications for these
- Class 3
- Class 2/2
- Class 2/1
- Class 1
In terms of canines, which canine is wider, upper or lower?
Upper
Which canine sits behind the other in canine relationship
the upper always sits behind the lower in a normal canine relationship (class 1)
What is the classification when the mesial slope of the upper canine overlaps the lower canines distal slope?
Class 1
What is the classification when the mesial slope of the upper canine sits further back on the lower canine distal slope?
Class 3
What is the classification when the mesial slope of the upper canine is parallel with the mesial slope of the lower canine slope?
Class 2 ½ unit
What is the classification when the distal slope of the upper canine is on the mesial slope of the lower canine slope?
Class 2 full unit
The horizontal overlap of the teeth (central incisors) is best known as?
Overjet
When there is no overlapping of the upper and lower teeth, we call this?
Open bite
What is the most common cause for an open bite?
Thumb sucking
When determining centrelines, if there is a shift how do you mark this on the assessment sheet?
Draw an arrow indicating the direction of the shift along with how much in shift
Crossbite assessment are used for which teeth?
Posterior and anterior teeth
What is a buccal crossbite?
Buccal Crossbite: the buccal cusps of the lower teeth occlude buccal to the buccal cusps of the upper teeth
What is a lingual crossbite?
Lingual Crossbite: the buccal cusps of the lower teeth occlude lingual to the lingual cusps of the upper teeth. Also known as scissor bite
What is the relevance of age and sex when completing a orthodontic diagnosis and treatment planning sheet?
Growth spurt
- Males – boys tend to show the first physical changes of puberty between the ages of 10 and 16. They tend to grow most quickly between ages 12 and 15. By age 16, most boys have stopped growing.
- Females - Most girls start their sexual development between the ages of 8 and 13 (the average age is 12), and have a growth spurt between the ages of 10 and 14
If there is a presenting complaint, what should you ask the patient?
- Getting worse
- Getting better
- How long have you been aware of problem?
What information do you need to obtain during a dental history?
- Caries history
- Restorations
- Extractions
- Home dental care
- Previous experience of orthodontics
- Anaesthesia for dental procedures (LA or GA)
- Trauma
If a patient has suffered from infective endocarditis what information needs to be obtained?
- History cardiologist
- Antibiotic cover (orthodontic procedures and extractions)
What is the relevance of a patient having Asthma for orthodontic appliance?
- Ask patient to bring inhaler with them or emergency box
- Avoid stressing the patient
- Children with hay fever may find removeable appliance difficult to wear in the summer months.
What is the percentage of the population that are hypersensitive to nickel?
4-29%
Why does nickel allergy need to be taken in to account in orthodontic history taking?
Because nickel is present in the majority of orthodontic alloys
What would you expect to see with someone who has nickel allergy suffering from contact dermatitis?
- Rash or bumps on the skin.
- Itching, which may be severe.
- Redness or changes in skin color.
- Dry patches of skin that may resemble a burn.
- Blisters and draining fluid in severe cases.
What is the protocol for patients who have poorly controlled epilepsy?
Avoid appliances as this would cause damage to self and appliance
What is the name of the epileptic drug that may cause gingival hyperplasia?
Phenytoin
During the social history section, what information are you hoping to obtain?
Factors affecting ability to attend over a regular basis over a prolonged time period.
What are the external/internal motivation factors for orthodontic treatment?
- External: Parent and GDP.
- Internal: patient
What habits do you need to be aware when taking an orthodontic diagnosis and treatment planning sheet?
- Digit or finger sucking
- Dummy sucking
- Nail biting
- Mouth breathing
What is the abbreviation AFA for?
– adjust fixed appliance
What is the abbreviation URA for?
– upper removeable appliance
What is the abbreviation VFR for?
– Vacuum formed retainer
What is the abbreviation NiTi for?
– Nickel Titanium
What is the abbreviation SS for?
– stainless steel (014, 016, 018, 020, 14x25, 16x22, 17x25, 18x25, 19x25)
What is the abbreviation TKNA for?
– To Keep Next Appointment
What is the abbreviation 6/52 for?
– 6 weeks
What is the abbreviation 6/12 for?
– 6 months
How do we assess symmetry?
- Line of fifths
- Birds eye view
- Worms eye view
What are the facial thirds in vertical dimension?
- Glabella
- Subnasle
- Soft tissue chin
What are the problems with a lip trap?
- Unesthetic
- Increase in overjet
- Risk of trauma
What are the causes for an incompetent lip?
- Proclined uppers
- Short upper lip
What’s the normal nasolabial angle?
90-110 degree
What could decrease nasolabial angle?
Proclined upper, protruded maxilla
What could increase the nasolabial angle?
Retruded maxilla, retroclined incisors
What are the causes for midline diastema?
- Frenal attachment
- Racial predilection
- Supernumerary – mesiodens
- Odontome
- Cysts
- Habits
What are the causes for generalised spacing?
- Missing teeth
- Microdontia
- Jaw size – tooth size discrepancy
- Periodontal problems
- Macroglossia
- Habits
What are the four factors governing eruption of canine?
- Position of tooth bud in bony crypt
- Path of eruption
- Shape and position of lateral incisors
- Amount of space available for canines in the arch
Classification of palatally impacted canine is based on two variables:
- Transverse relationship of the crown of the tooth to the line of dental arch which may be what? Close or distant (nearer the midline)
- Height of the crown of the teeth in relation to the occlusal plane which may be? High or low
what is the classification of this palatally impacted tooth based on transverse relationship of the crown of the tooth to the line of dental arch and the height of the crown of the teeth in relation to the occlusal plane?
- proximity to the line of arch = close
- position in the maxilla = low
what is the classification of this palatally impacted tooth based on transverse relationship of the crown of the tooth to the line of dental arch and the height of the crown of the teeth in relation to the occlusal plane?
- proximity to the line of arch = close
- position in the maxilla = high
what is the classification of this palatally impacted tooth based on transverse relationship of the crown of the tooth to the line of dental arch and the height of the crown of the teeth in relation to the occlusal plane?
- proximity to the line of arch = distant
- position in the maxilla = high
if a permanent canine hasn’t erupted yet, what would you expect to see clinically?
- Non-appearance of permanent canine clinically by its eruption age
- Presence of antimere (no symmetry)
- Presence of anterior spacing for a long period
- Persistent median diastema
- Abnormal morphology of lateral incisors or presence of peg laterals
- Improper angulations of adjacent teeth
When do permanent canines erupt?
Between 9 – 13 years
Bulge of permanent canine could be palpated buccally above the deciduous canine when?
2-3 years before its eruption.
What is the purpose of occlusal radiographs?
Occlusal X-rays show the roof or floor of the mouth and are used to find extra teeth, teeth that have not yet broken through the gums, jaw fractures, a cleft palate, cysts, abscesses or growths.
How does the SLOB principle work?
If the object has moved on the same as that of the x-ray tube it is lingually placed and if it has moved on the opposite side, it is on the buccal side.
What are the factors influencing the treatment decision of an impacted canine?
- Position of canine favourable or unfavourable
- Age of patient
- Availability of space
- Presence of adequate width of attached gingiva
What are the treatment alternatives for impacted canines?
- No treatment, if the patient does not desire it
- Auto transplantation of the canine
- Extraction of impacted canine and moving premolar in its position
- Extraction of the canine & posterior segmental osteotomy to move the buccal segment mesially to close the residual space
- Prosthetic replacement of the canine, not amendable for juvenile cases
- Most desirable approach is surgical exposure of the canine followed by orthodontic treatment
What are the causes for midline diastema?
- Frenal attachment
- Racial predilection
- Supernumerary – mesiodens
- Odontome
- Cysts
- Habits
What are the causes for generalised spacing?
- Missing teeth
- Microdontia
- Jaw size – tooth size discrepancy
- Periodontal problems
- Macroglossia
- Habits
What are the four factors governing eruption of canine?
- Position of tooth bud in bony crypt
- Path of eruption
- Shape and position of lateral incisors
- Amount of space available for canines in the arch
Classification of palatally impacted canine is based on two variables:
- Transverse relationship of the crown of the tooth to the line of dental arch which may be what?
- Height of the crown of the teeth in relation to the occlusal plane which may be?
Close or distant (nearer the midline)
High or low
what is the classification of this palatally impacted tooth based on transverse relationship of the crown of the tooth to the line of dental arch and the height of the crown of the teeth in relation to the occlusal plane?
- proximity to the line of arch = close
- position in the maxilla = low
what is the classification of this palatally impacted tooth based on transverse relationship of the crown of the tooth to the line of dental arch and the height of the crown of the teeth in relation to the occlusal plane?
- proximity to the line of arch = close
- position in the maxilla = high
what is the classification of this palatally impacted tooth based on transverse relationship of the crown of the tooth to the line of dental arch and the height of the crown of the teeth in relation to the occlusal plane?
- proximity to the line of arch = distant
- position in the maxilla = high
if a permanent canine hasn’t erupted yet, what would you expect to see clinically?
- Non-appearance of permanent canine clinically by its eruption age
- Presence of antimere (no symmetry)
- Presence of anterior spacing for a long period
- Persistent median diastema
- Abnormal morphology of lateral incisors or presence of peg laterals
- Improper angulations of adjacent teeth
When do permanent canines erupt? Between
9 – 13 years
Bulge of permanent canine could be palpated buccally above the deciduous canine when?
2-3 years before its eruption.
What is the purpose of occlusal radiographs?
Occlusal X-rays show the roof or floor of the mouth and are used to find extra teeth, teeth that have not yet broken through the gums, jaw fractures, a cleft palate, cysts, abscesses or growths.
How does the SLOB principle work?
If the object has moved on the same as that of the x-ray tube it is lingually placed and if it has moved on the opposite side, it is on the buccal side.
What are the factors influencing the treatment decision of an impacted canine?
- Position of canine favourable or unfavourable
- Age of patient
- Availability of space
- Presence of adequate width of attached gingiva
What are the treatment alternatives for impacted canines?
- No treatment, if the patient does not desire it
- Auto transplantation of the canine
- Extraction of impacted canine and moving premolar in its position
- Extraction of the canine & posterior segmental osteotomy to move the buccal segment mesially to close the residual space
- Prosthetic replacement of the canine, not amendable for juvenile cases
- Most desirable approach is surgical exposure of the canine followed by orthodontic treatment
What types of parallaxes can be used to localise the position of an ectopic canine?
Parallax is the key to effective evaluation with radiographs. Parallax refers to the apparent movement of an object based on the position of the beam.
This allows localisation of the canine. We must consider the movement of the x-ray tube relative to the canine position and apply the SLOB rule – Same Lingual Opposite Buccal i.e. if the tube and the canine move in the same direction, then the tooth is likely lingually positioned.
There are 2 types of parallax that could be used:
- Horizontal parallax – this could either be 2 periapical radiographs, or a periapical and an upper standard occlusal
- Vertical parallax – an upper standard occlusal and OPT or a periapical and an OPT
What different options are there for managing an ectopic canine?
- Extractions
- Surgical exposure associated with orthodontic movement of impacted canine.
Ectopic canines are most commonly involving the maxilla. Early identification is required for referral and effective management Typically, canines should be palpated at?
9-10 years of age, and should erupt a few years later
Clinical examination is key to early identification of ectopic canines. Palpation for maxillary canines should begin around the age of 9 in the buccal sulcus. Features to assess clinically include:
- An absence of a buccal canine bulge is an indication of impaction
- Presence of a palatal swelling may indicate palatal positioning
- Mobility of deciduous canine – a lack of mobility may be concerning
- Arch space – a lack of space may promote impaction
- Splaying or angulation of the lateral incisor may indicate abnormal positioning
There are numerous management options for ectopic canines, under what condition should interceptive extraction of deciduous canine be done?
- This is only suitable if the permanent canine is minimally displaced
- It must be done before the age of 13, ideally before the age of 11
There are numerous management options for ectopic canines, under what condition should you do surgical exposure and orthodontic alignment?
This would either be through an open (allowing natural eruption) or closed (bonding a chain) exposures.
- Patients must be well motivated to undergo surgical and orthodontic treatment, including wearing fixed appliances
- Cases where interceptive treatment is not feasible
- Canine is not so grossly displaced that it is unlikely to move sufficiently
There are numerous management options for ectopic canines, under what condition should you surgically remove the ectopic canine
Assessment of the existing dentition is crucial to treatment planning e.g. consideration of space between the lateral and first premolar and camouflaging appropriately. Indications include:
- The patient may not want intensive orthodontic management or may not be co-operative to wearing fixed appliances
- Root resorption may be identified of adjacent teeth
There are numerous management options for ectopic canines, under what condition should you do transplantation?
This option is only considered when other options are not feasible or have failed. Possible indications and requirements include:
- Patient has declined active orthodontic treatment
- Deciduous canines have a poor prognosis
- Sufficient room within the arch to accept the canine
Ideally, this should be carried out prior to complete root formation.
If the root is >75% formed, the likelihood of requiring root canal treatment increases.
Recap when to take X-Rays:
DIAGNOSIS:
- Locate unerupted teeth
- Confirm unerupted teeth
- Pathology
Recap when to take X-Rays:
TREATMENT PLANNING
- Root morphology
- Assess skeletal pattern
- Monitor treatment changes
When are orthodontic radiographs indicated?
Following a clinical examination and before requesting radiographs the following questions should be asked:
- Do I need it – does the management of the patient’s condition depend upon a radiograph
- Do I need it now? Is it likely that the condition will resolve or progress?
- Has it been done already? Repeat radiographs deliver additional radiation dose.
- Is the correct radiograph being requested?
- Is a radiograph essential for diagnosis and justified?
- Have I made a clinical assessment?
To assume that a radiograph is necessary to complete a diagnosis and request a radiograph before a clinical examination, in order to facilitate patient flow though a clinic or practice
is UNLAWFUL.
When would you take X-Rays?
- When clinically indicated
- When it will change the treatment plan
- BOS guidelines (take radiographs only when justified clinically, this is a legal requirement in the UK)
What is Cephalometrics?
Is the analysis and interpretation of standardised radiographs taken on different occasions or of different patients.
Why bother with Cephalometric analysis?
- Diagnosis and planning
- Skeletal discrepancy
- Incisor relationship
- Monitoring treatment
- Functional appliances
- Incisor changes
What is indicated by S:
this is the point representing the midpoint of the pituitary fossa
What is indicated by N?
the most anterior point of the frontonasal suture in the median plane.
What is indicated by Point A?
the point at the deepest midline concavity on the anterior maxilla, this represents the anterior limit of the maxilla. This point is on the ALVEOLAR BONE can change with growth and tooth movement.
What is indicated by point ANS?
Anterior nasal spine, this is the tip of the bony anterior nasal spine, in the medial plane.
What is indicated by point PNS?
Posterior nasal spine, the tip of the posterior nasal spine, can be obscured by developing upper 8s
What is indicated by point B?
- The point at the deepest concavity on the mandibular symphysis
- Is located on alveolar bone and can change with growth and tooth movement
What is indicated by point Pog?
Pogonion, the most anterior point of the mandibular symphysis
What is indicated by point ME?
Menton, the most inferior point on the mandibular symphysis
What is indicated by point Go?
Gonion, the constructed point of intersection of the tangents of the ramus plane and the mandibular plane, which is the most posterior and inferior point on the angle of the mandible.
What does SNA Angle indicate?
This angle indicates the relative antero-posterior positioning of maxilla in relation to cranial base. Connecting the locations:
1. Sella
2. Naison
3. A – deepest concavity of the maxilla
what is the mean reading of the SNA angle?
82 degrees
if there is an increased SNA angle what does this indicate?
Prognathic maxilla (>82 degrees)
if there is a decreased SNA angle what does this indicate?
Retrognathic maxilla (<82 degrees)
What does SNB Angle indicate?
This angle indicates the antero-posterior positioning of mandible in relation to cranial base. Connecting the locations:
1. Sella
2. Naison
3. Point B - deepest concavity on the mandibular symphysis
What is the mean reading of the SNB angle?
80 degrees
if there is an increased SNB angle what does this indicate?
Prognathic mandible (>80 degrees)
if there is a decreased SNB angle what does this indicate?
Retrognathic mandible (<80 degrees)
What does ANB Angle indicate?
This angle it donates the relative position of maxilla and mandible to each other. Connecting the locations:
1. Naison
2. Point A
3. Point B
What is the mean reading of the ANB angle?
2 degrees
if there is an increased ANB angle what does this indicate?
Class 2 skeletal pattern (>4 degrees)
if there is a decreased ANB angle what does this indicate?
Class 3 skeletal pattern (<2 degrees)
What is the MMPA indicate?
This is the Maxillo-Mandibular plane angle, which is formed by intersection of mandibular plane with maxillary plane. Connecting locations
1. ANS
2. PNS
3. Menton
4. Gonion
what is the mean reading of the MMPA?
27 degrees
an increased MMPA indicates what?
Vertical growth pattern
a decreased MMPA indicates what?
Horizontal growth pattern
How is the incisor angle measured?
A line is placed through the incisors and intersected with the maxilla/mandibular plane angle
What is the mean angle for the maxilla incisors?
110 degrees
What is the mean angle for the mandible incisors?
90 degrees
If there is an increased incisor angle what does that result in?
proclined
If there is a decreased incisor angle what does that result in?
retroclined
If there is a decreased incisor angle what does that result in?
retroclined
What does the rickets Esthetic plane show?
- Line joins soft tissue chin and nose tip
- In a balanced face
- Lower lip = 1-2 mm
- Upper lip = 2-3 mm
What does IOTN stand for?
Index of orthodontic treatment need
When is the IOTN completed?
After having completed the diagnosis of a case.
What was the purpose of the IOTN?
The purpose of the index was to help determine the likely impact of malocclusion on an individual’s dental health and psychosocial well-being. It has two components:
IOTN has two components what are they?
– Dental Health Component / Aesthetic Component
How is the aesthetic component calculated for the IOTN?
- 10-point scale using a series of photographs. 1 = best 10 = worst
- Rating is allocated for overall attractiveness rather than specific similarity to photographs
- Scoring reflects treatment need on basis of aesthetic impairment, and by implication, psychological need for treatment
The dental health component of the IOTN records the various traits of a malocclusion that would increase the morbidity of the dentition. Each occlusal trait is given a letter e.g.
A = overjet
B = Reverse overjet
C = crossbite
D = Displacement of contact points
E = Open bite (lateral or anterior)
F = Overbite
G = Pre – or post-normal occlusions with no other anomalies
T = partially erupted teeth, tipped and impacted against adjacent teeth
X = Presence of supernumerary teeth
I = impeded eruption of teeth
H = extensive hypodontia
M = reverse overjet with reported masticatory and speech difficulties
P = Defects of cleft lip and palate and other craniofacial anomalies
S = submerged primary teeth
What do the grades for the IOTN mean?
- Grade 1 = no or little treatment
- Grade 2 = no or little treatment
- Grade 3 = borderline need
- Grade 4 = need treatment
- Grade 5 = need treatment
What does MOCDO stand for?
DHC only the most severe single occlusal trait is recorded
M = missing
O = overjet
C = crossbite
D = Displacement
O = Overbite
Teeth can be missing as a result of congenital absence or impeded eruption, which missing tooth is excluded from the IOTN?
3rd molars
Teeth can be missing as a result of congenital absence or impeded eruption, one tooth missing in a quadrant would score what on the IOTN scale?
4H - must decide whether to space open or close space
Teeth can be missing as a result of congenital absence or impeded eruption, two or more teeth missing in a quadrant would score what on the IOTN scale?
5H – must decide whether to space open or close space
Retained deciduous canine would score what on the IOTN?
5i
Impaction/impeded eruption would score what on the IOTN?
5i
Increased overjet > 9mm would score what on the IOTN?
5a
Reverse overjet > - 3 1/2 mm would score what on the IOTN?
5m or 4m depending on if there are speech or masticatory difficulties
Anterior crossbite or unilateral buccal crossbite with mandibular displacement > 2mm would score what on the IOTN?
4c
Scissor bite in one or both buccal segments would score what on the IOTN?
4l
Contact point displacement of >4mm would score what on the IOTN?
4d
Contact point displacement of 2 to 4 mm would score what on the IOTN?
3d
Contact point displacement >1mm < 2mm would score what on the IOTN?
2d
Would you measure displacements due to rotations?
No
NHS not funding cases with IOTN grades less than what?
< 3.6
