Second Semester Flashcards
Describe the characteristics of a patient that would be at high risk of substantial external root resorption?
Already short roots
Conical/blunted root tips
Teeth need to be moved a long distance (closing extraction space)
Pt needs camouflage treatment (roots may bump against cortical plate)
Describe the two normal postural lip positions
Relaxed: lips apart, relaxed, and hanging loosely with no contraction
Closed lip: lips are lightly touching to seal the oral cavity, minimal contraction to achieve this anterior closure
Describe the abnormal lip position present in a class 2 div 1 case with significant overjet.
Closed lip: light contact between lower lip and maxillary incisors
Greater mentalis strain is noted to achieve closure
Describe three techniques to find the relaxed lip position
For all three techniques, FH should be parallel to floor.
1) lightly jiggle mandible up and down as if trying to locate CR
2) Stroke the lips with fingers to relax lips and form the space between lips
3) instruct pt to relax lips
Which is the least reliable method to find relaxed lip position?
Instructing the patient to relax their lips
When evaluating lip posture should the teeth be together or apart?
Together
The interlabial gap is influenced by what two things?
Length of the lips
Variation in skeletal height in the anterior portion of face
It has been noted that the malocclusion with the shortest upper lip length is class ___
2 div 1
A useful plane to evaluate lip protrusion is ____
Subnasale - soft tissue pogonion
On average, the upper lip is ___ and the lower lip is ___ anterior to the subnasale-soft tissue pogonion line
- 5mm
2. 2mm
What is the typical angle for the nasolabial angle?
74 degrees
The ___ should be considered the most important element in determining a stable position for the incisors
Lips
True or false… a retruded lip pressed against a lower incisor is less suggestive of the desirability of protruding the lower incisor during treatment than a lip that is protruded and lying away from the incisor
True
Normally, a relaxed lower lip will contact the ___ at the ___
Lower incisor
Junction of its incisal and middle thirds
True or false… if the interlabial gap is large, protrusion of the teeth is more stable.
False
Without considering growth, the most dramatic facial changes following retrusion of teeth are seen in cases where there is a ___
Large interlabial gap
___ relaxed lip posture is associated with protrusive dentition and ___relaxed lip posture is associated with retrusive dentition
Protrusive
Retrusive
Describe the lower lip resting position in Class 2 div 1 and Class 2 div 2.
Class 2 div 1: lower lip rests lingual to the upper incisors and exerts labial pressure
Class 2 div 2: lower lip rests labial to the upper incisors and exerts lingual pressure
What is the soft tissue facial angle?
Angle between FH and line from soft-tissue nasion to soft-tissue chin
91+/- 7 degrees
How did Holdaway measure nose prominence?
Line perpendicular to FH, tangent to vermillion of upper lip. Measure of tip of nose to this line
Normally 16mm . (<14 = small, >24 = large)
How did Holdaway measure the superior sulcus depth?
Used the same line to measure nose prominence
3mm ideal (less than 1.5 should be avoided)
This is the most frequently criticized area with retraction of anterior teeth
Holdaway found that upper lip thickness measured at the vermillion follows tooth movement. Notably, very thick lips (~__mm) will be slow to follow tooth movement, very thin lips (~___mm) will be fast to follow tooth movement
16mm+
12mm-
The lips and chin should line up near the ___
H line
What is the ratio for esthetic balance of upper face (glabella to subnasale) to lower face (subnasale to soft-tissue menton)?
1:1
In repose, normally stomion superior to incisal edge is ___mm
1-5mm
Smiling, the ideal maxillary incisor exposure is ____
3/4 of crown height to 2mm of gingiva
The upper lip should be ___mm posterior to the E line. The lower lip should be __mm posterior to the E line.
4mm
2mm
If a patient begins treatment with minimal display of the upper lip vermillion border, how might dental retraction produce a less esthetic result?
There will be some reduction in the display of the upper lip vermillion border
If the patient’s initial incisor overjet was caused by extreme upper incisor proclination, then uprighting tends to cause ___. On the other hand If the initial incisor inclination was relatively normal and was retracted by translators movement it tends to cause ___.
Less lip change
More lip change
There is [less/more] retraction of the upper lip when patients initially present with lip incompetence
More
What type of radiographs are important in asymmetry cases, dental/skeletal crossbites, and functional mandibuar displacements?
PA and basilar cephs
Natural head position is reproducible within a range of ___ degrees
2
True or false… less exposure is needed for PA cephs than lateral cephs
False. More exposure is needed for PA cephs than lateral cephs
How can vertical asymmetry be analyzed using a PA ceph?
Vertical asymmetry can be observed by connecting bilateral structures or landmarks, by drawing the transverse planes, and by observing their relative orientation
In orthodontics, the primary indication for obtaining a PA ceph is ____
The presence of facial asymmetry
Natural head position is important in all radiographs but even more -so in PA cephs. In a PA ceph, The ___ the distance between anatomic structures, the less the distortions are due to head positioning. The ___ the distance, the greater the distortions.
Shorter
Greater
The FH plane is usually positioned parallel to the floor of the X-ray room. the upper margin of the petrous portion of the temporal bone (Porion?) passes through the ___of the ___
Middle to lower 1/3rd
Orbital cavity
The floor of the nasal cavity is NOT flat. Therefore, the ANS and PNS are not superimposed in a PA ceph. If the head is tilted ____, the odontoid process is higher than the other structures and the PNS will be higher than the ANS. If the head is tilted____, the odotnoid process will be located below the ANS.
Downward
Upward
If the upper facial height is longer than the lower part of the face in the PA ceph compared to the lateral ceph, then the subjects head was tilted ____ in the PA ceph. If the patient’s head was tilted ___, the entire PA ceph will show a longer facial image.
Upward
Downward
In determining if a PA ceph was rotated, the ____should be clear and straight, if the patient was rotated it will become obscure. If the patient was rotated, the ___ appears different on both sides. It will appear wider on the side that is further from the film. There should be ____space between the maxillary alveolar bone and the inner surface of the ramus.
Nasal septum
Width of the ramus
Equal
Only the ___of the pituitary fossa can be seen in a PA ceph
Floor
In a PA ceph, labially inclined teeth give you a ___ image than lingually inclined teeth
Shorter
Maxillary posterior teeth erupt in a ___ fashion while the mandibular posterior teeth erupt in a ____ fashion.
Straight downward
Lingually inclined
The PA ceph is useful for two important diagnostic factors. What are they?
Assessment of symmetry
Measurement of the skull and denture widths (You don’t want to expand someone pas their cranial base.)
True or false… all horizontal lines connecting bilateral cranial landmarks can adequately serve as reference lines in the PA analysis of vertical asymmetry, if acceptable landmark identification error
True
The best vertical reference lines in PA cephs are perpendicular to horizontal lines connecting ___, if minimal landmark identification error
Bilateral cranial landmarks
What are the three main limitations of PA cephs?
1) Difficulty in reproducing natural head position
2) Difficulty in landmark identification due to superimposed structures or poor radiographic technique
3) concern of radiation
The preciseness of measurements of head films may be influenced by various errors such as…
Projection error
Landmark identification error
Measuring technique error
In a PA ceph, the horizontal differences are larger if the landmark is located ____ from the vertical rotational axis and smaller if the landmark is located____ the vertical rotational axis.
Further
Nearer
In a PA ceph, landmarks ___ to the vertical rotational axis move in the same direction as head rotation, whereas landmarks ___ to the vertical rotational axis move in the opposite direction as head rotation
Anterior
Posterior
True or false… rotation of the head along the Y axis (head tilted side to side) does not cause distortion of the image
True because the location of the head is still parallel to the central ray
True or false… in a PA ceph, tilting the head up or down (Nodding yes) does not significantly affect assessment of asymmetries of the face
True, because it will affect the relationship of landmarks vertically, not horizontally
According to a s study by Peng L and Cooke, only 2/20 subjects showed changes in natural head position of ___ or more after ___ years
5 degrees
15 years
True or false… natural head position has been shown to be remarkable reproducible even after 15 years. It is a more reliable reference plane for cephalometric analysis than intracranial reference planes
True
What is the difference between natural head position and natural head orientation?
NHP: Taken when subject is looking at a distant point at eye level
NHO: Position the orthodontist believes the pt’s head would be if they looked straight ahead at a distant point at eye level
____ is a significant factor in affecting natural head orientation (not NHP).
Chin position
The validity of NHO in diagnosis and treatment planning is therefore questioned.
True or false, the curvature of the mandibular canal and third molar tooth germ can serve as natural references for superimposition of the mandible
True
Radiographic cephalometry superimposition is limited by what 5 problems?
1) headfilms taken at different times are difficult to reproduce with any degree of accuracy
2) the double images of bilateral structures are not consistently equally spaced in serial headfilms because of faulty head positioning
3) Film contrast and density differences
4) Anatomical or structural landmarks not consistently identifiable
5) 3d changes are only measured in 2d
For overall craniofacial growth, displacement, and treatment effects, one should superimpose on ___ registering at ____.
SN (sella-nasion) line
Sella
For maxillary complex growth and treatment effects, the best fit for superimpositioning is on the _____
Palatal surface of the maxilla parallel to ANS-PNS
For mandibular growth and treatment effects, one should superimpose on the ____ of the ___ and on the ___.
Lingual contour
Symphysis
Inferior alveolar canal
True or false… superimpositions are not completely accurate but are valuable when assessing overall change due to growth and treatment
True
Define natural head position
The position of the head with the subject standing and the visual axis parallel to the horizontal plane
Overtime, does NHP tend to result in patient looking slightly up or down?
Slightly down
Both Sagittal and transversal NHP have been shown to be reproducible after 2 years
What are the four positions in Rickett’s four step method to distinguish orthodontic changes from natural growth?
Chin
Maxilla
Maxillary teeth
Mandibular teeth
___ degree is a useful rule for expected variation of the chin (due to natural growth/development) over a two-year treatment period. Therefore, if a patient under treatment opens up more than ___ degrees, there is a high change that the orthodontic treatment caused the opening.
1
2
A change in the maxilla evaluating the Ba-N-A angle during treatment can be assumed to be due to ___ and not ___.
Treatment
Growth
Rickett’s position three (relative to maxillary teeth), consists of superimposing the ___ and ___, registered at ___. This is considered a ___ position naturally, meaning…
ANS
PNS
ANS
stable
Any backward or forward change in teeth in 2 years can be attributed to treatment, not growth
Abnormally enlarged sella turcica, poorly defined posterior and anterior clinoid processes, and short cranial base are all findings that indicated a problem with the ___
Pituitary gland
Individuals with ____ have increased incidence of cervical spine abnormalities
Cleft lip/palate
What is an odontoidium?
It is a potentially fatal developmental spinal abnormality
When the body of the odontoid process and axis have separated, which can lead to subluxation of C1 or C2, which may cause spinal cord damage
On a lateral ceph it appears as a small, ovoid radiopacity superior to the arch of C1 and odontoid process
In orthodontics, when should cephs be examined for pathology?
Prior to beginning treatment
The radiographic shape of the sella turcica is highly variable. What are the three basic shapes?
Oval
Circular
Flat
What are four possible radiographic indications of pathology of the sella?
Double floor
Thinning or ballooning of floor
Erosion of the lamina dura
Erosion of the dorsum sella
What is the most common cause of an enlarged sella?
Primary intrasellar pituitary tumor
According to a study on the frequency with which an orthodontist can expect to discover pathology, remarkable radiographic findings were reported in ___% of cases.
6.2%
What is the most commonly reported finding reported from orthodontic radiographs?
Mucous retention cysts
They are frequently non-pathologic, yet they can be associated with symptoms
A ___ approach should be used when examining radiographs for pathology.
Systematic
Because of individual variation, physiological and anatomical maturity cannot be assessed accurately by chronically age alone. Better parameters of anatomical maturity include…
Growth velocity
Secondary sex changes
Dental development
Skeletal ossification
Orthodontists do not necessarily need to know the exact skeletal age of a patient. Instead, what is important to know for the orthodontist?
Whether will patient will grow at all during a 1-2 year treatment period and what percentage of growth can reasonably be expected during that time.
A study by Lamparski (1972) concluded that the cervical vertebrae (as viewed in lateral ceph) were _____ in assessing skeletal age as the hand wrist technique
As statistically and clinically reliable
Describe the initiation cervical vertebral stage (SMI 1 and 2).
The vertebrae are wedge-shaped, with the superior vertical borders tapering from posterior to anterior. 80-100% of adolescent growth can be anticipated at this stage.
Describe the acceleration cervical vertebral stage (SMI 3-4).
Growth acceleration begins at this stage when 65-85% of adolescent growth can be anticipated. Concavities develop on the inferior borders of C2 and C3. The bodies of C3 and C4 are nearly rectangular, and the inferior border of C4 is flat.
Describe the Transition cervical vertebral stage (SMI 5-6).
Adolescent growth accelerates toward peak velocity, with 25-65% of adolescent growth anticipated. Distinct concavities develop on the inferior borders of C2 and C3. A concavity begins to develop on the inferior border of C4, and the bodies of C3 and C4 are rectangular
Describe the Deceleration cervical vertebral stage (SMI 7-8).
Only 10-25% of adolescent growth remains. Clear concavities are seen on the inferior borders of C2, C3, and C4 with the bodies of C3 and C4 becoming more square-like.
Describe the Maturation cervical vertebral stage (SMI 9-10).
Final maturation takes place at this stage, when only 5-10% of adolescent growth can be anticipated. Accentuated cavities are seen on the inferior borders of C2, C3, C4, and the bodies of C3 and C4 are nearly square.
Describe the Completion cervical vertebral stage (SMI 11).
Little to no adolescent growth is expected at this point. Deep concavities are seen on the inferior borders of C2, C3, and C4, and the vertebral bodies are more vertical than horizontal.
True or false… the cervical vertebrae technique in assessing growth status is race-neutral
True
Four ossification stages of bone maturation in the hand wrist radiograph are evaluated at ____ anatomical sites located on the ___, ___, and ___. ___ skeletal maturation indications are found on these sites.
6
Thumb
Third finger
Fifth finger
11
What are the four ossification stages on a hand-wrist radiograph?
Epiphyseal widening on selected phalanges
Ossification of adductor sesamoid of the thumb
‘Capping’ of selected epiphyses over their diaphysis
Fusion of selected epiphyses and diaphyses
Describe SMI 1-3 in a hand-wrist radiograph
Width of epiphysis as wide as diaphysis
- 3rd finger - proximal phalanx
- 3rd finger - middle phalanx
- 5th finger - middle phalanx
Describe SMI 4 in a hand-wrist radiograph
Ossification
4. Adductor sesamoid of thumb
Describe SMI 5-7 in a hand-wrist radiograph
Capping of epiphysis
- 3rd finger - distal phalanx
- 3rd finger - middle phalanx
- 5th finger - middle phalanx
Describe SMI 8-11 in a hand-wrist radiograph.
Fusion of epiphysis and diaphysis
- 3rd finger - distal phalanx
- 3rd finger - proximal phalanx
- 3rd finger - middle phalanx
- Radius
What is the first step in evaluating a hand-wrist radiograph?
Evaluate if adductor sesamoid of the thumb is visible or not.
If not visible, applicable SMI will b associated with early epiphyseal widening rather than caping
If visible, either the sesamoid or an SMI based on capping or fusion will be applicable
In a hand-wrist radiograph, at SMI 6, all values showed about __% completion of adolescent growth
50%
True or false… facial growth shows a close direct association between variations in the rate of growth in skeletal maturation
True
although maxillary and mandibular growth rates peaked later than statuary height and statuary height demonstrated a greater percentage of completed growth than facial growth in the middle to late adolescent growth period
True or false… tooth development criteria are sufficiently reliable to indicate the pubescent growth spurt.
False.
____ mineralization appears to correlate better with ossification stages than other teeth.
Mandibular canine
The ____ phalanx shows the highest relationship with canine maturity
Third middle
Bjork, and others, found that capping of the epiphyses of the ___ phalanx was closely related to the pubertal maximum growth velocity
Third middle
Mandibular canine stage ___ indicates the initiation of puberty. Canine stage ___ is consistent with capping of the third middle and fifth phalanges and the presence of the adductor sesamoid, indicating PHV. Describe these canine stages.
F: walls of pulp chamber form an isosceles triangle with apex ending in a funnel. The root length is equal to or greater than the crown height.
G: the walls of the root canal are now parallel and its apical end is partially open
Although there is a close association between mandibular canine calcificaiton stages and skeletal maturity, canine calcificaiton should not be the sole criteria to predict PHV
Most studies have found that the growth height peak corresponds with ___ and __ peak growth
Maxillary
Mandibular
Cervical stages __ through ___ are pre peak growth and accelerative growth phase. Cervical stages ___ through ___ are post peak growth and decelerative growth phase. Peak growth occurs between CVs __ and ___.
1-3
4-6
3 and 4
Cervical stage ___ is the closest stage to the onset of peak growth.
Mean age for girls is ___ -___
Mean age for boys is ___-___
3
8.6-11.5 years old
10-14 years old
____ growth peak during the transition from CVs3 to CVs4 corresponds with ___ growth peak
Statural height
Mandibular
Does the mandible and midface more closely follow the neural growth curve or the somatic growth curve?
Somatic
The craniofacial complex phenotype is a result of the ___ and the ___ and ___ environment
Genome
Intrinsic
Extrinsic
Normal ___ is greatest in early development and reduces with maturation
Adaptation
What are three factors that affect whether the craniofacial skeleton will respond positively to orthodontic-orthopedic treatment?
1) Availability of precursor mesenchymal stem cells (tissue type)
2) Capability for growth factor expression (developmental age and sex)
3) Local environment (treatment duration and mechanics)
The conclusion of a study by Dolce et al (2005) was that the skeletal effects of ____ treatment disappear by the end of fixed appliance treatment (phase 2)
Phase 1 class 2
In a multicenter study conducted in the UK, early orthodontic treatment with the twin-block appliance resulted in substantial reduction in the ___ of children with class 2 malocclusion that was mainly due to ___ changes. The results of the study reinforce others by suggesting early functional appliances do not, on average, influence the class 2 skeletal pattern to a ___ degree
Overjet
Dentoalveolar
Clinically significant
According to a study by Tulloch et al, the advantage created during phase one class ___ treatment was lost and by the end of fixed appliance treatment there was no significant differences between any of the groups for all AP and vertical skeletal and dental measures.
2
In the study conducted by Tulloch et al, evaluating phase 1 class 2 treatment, there was no statistically significant difference in scores comparing the children who had early treatment and those who did not. There was no statistically significant effect related to the ____.
Orthodontist
Early treatment of ____ has little effect on the subsequent treatment outcomes measured as skeletal change, alignment, and occlusion of the teeth, or the ___ and complexity of treatment
Class 2
Length
Early Phase 1 treatment of class 2 might be no more clinically effective than a single compressive phase started during ____. Early treatment also appears to be less efficient in that it….
Adolescence in the early-permanent dentition
Produces no reduction in the average time a child is in fixed appliances during the second stage of treatment and it does not decrease the proportion of complex treatment involved extractions or orthognathic surgery
True or false… early treatment of class 2 (phase 1) decreases the length and complexity of phase 2 treament when compared to a single comprehensive treatment.
False
Early class 2 treatment is NOT an efficient way to treat most Class 2 cases
What are three therapies that may increase the stability of open-bite treatment in cases with abnormal tongue function?
1) Crib or sharp spur therapy (1-2 years)
2) Myofunctional therapy
3) Partial glossectomy
True or false… tonsillectomy and/or adenoidectomy have been shown to consistently improve the stability of open bite treatment in scenarios where the patient has allergies and/or enlarged adenoids
False.
Is early orthodontic treatment indicated for anterior open-bite malocclusions?
Yes, but it depends on many factors like severity, age, etiology, and parental concerns
Is stability of open bite treatment a clinical problem?
Yes
True or false… you can use a quad helix or reverse pull facemask with skeletal effects if the patient is in cervical stage 1 or 2
True
If the patient is in cervical stage 3, when are they expected to experience peak growth?
Within the year
True or false… you can use a quad helix with skeletal effects if the patient is in CS3
False, probably. Best to use a hyrax in this stage
What are four factors that can affect the amount of upper lip change when incisors are retracted?
Lip length
Lip toxicity
Lip thickness
Interlabial gap (incompetent lips will be affected more than competent lips)
True or false… every person has a certain degree of lip protrusion that will not be affected by the presence or absence of teeth
True.
What is the H line?
H line = Harmony line (developed by Holdaway)
Runs from soft tissue pogonion to the vermillion of the upper lip
Used to assess the protrusion of the lower lip and the concavities found below the lower lip or above the upper lip.
When Holdaway was constructing his VTO, he concentrated on the ___ and ___
Upper incisors
Lips
SMI ___ of the hand-wrist radiograph is associated with peak jaw growth velocity
7
In a study by Franchi and McNamara styling the long term effects of RPE, craniofacial structures [near/far] from the nasomaxillary area show the following changes:
Overall changes in RPE group [exceeded/were less than] those in the control.
There were significant [increases/decreases] in EU width (transverse cranial measurement), Lo width, and Mmd width.
far
exceeded
increases
Long-term effects of RME appear to involve an ample portion of the ___ with enhanced transverse growth of these regions
craniofacial complex
True or false… in the long-term (~8 years post expansion), the effects of RME with the Haas appliance followed by fixed appliance therapy can induce normalization of both dental and skeletal components of the craniofacial complex
true
____ is lost during the transition from mixed dentition to permanent dentition, particularly in the ___ arch.
Arch length
mandibular
According to a study by Gianelly, when crowding was not associated with early loss of ____, leeway space provided adequate space to correct crowding in 82% of cases
primary canines
According to one study: Theoretically, maintaining leeway space will resolve ___ of crowding cases in the mixed dentition. According to a second: clinically, maintaining leeway space resolved ___% of crowding cases
72%
68%
Timing of treatment to resolve crowding should be a the terminal phase of ___. However, what is one major exception? How should this be treated?
the mixed dentition
If a primary canine is loss too early, it will require immediate intervention to control both arch length and symmetry. The contralateral primary canine should also be extracted and lingual arch should be placed
RPE increases the perimeter of the maxillary arch and can correct __-__mm of crowding
3-4mm
What does the data say about spontaneous expansion of the mandibular arch as a result of REP?
Although some expansion of the mandibular arch may occur, it provides almost no space to resolve crowding in the lower arch
According to Grayson (1977), “the use of rapid palatal expansion as a method of increasing lower arch length [cannot/can] be justified
cannot
(while 1mm increase of lower inter canine dimension can provide 0.73mm of space to correct lower incisor position, 1mm of molar expansion only provides 0.27mm of space. )
According to Gianelly, it is unreasonable to justify the use of RPE in the absence of crossbones, particularly because…
any correction of the molar relationship could be unstable
A meta-analysis evaluating the immediate changes with RPE found that the greatest dental and skeletal changes were in the ___ dimension and occurred at the ___.
transverse
dentition
This confirms previous studies that RME produces more tipping than true palatal expansion but some skeletal expansion was still noted
According to a metaanalysis, RPE expansion was greater [anteriorly/posterior] because…
the RME appliances were anchored on posterior teeth
According to a meta-analysis, RPE [increases/decreases] overate by ___
increases
1.29mm
According to a meta-analysis evaluating the impact of RME on OSA, studies indicate that there is a decrease in ___ after maxillary expansion in children with OSA. Studies suggest that the decrease is [lost/maintained] over 3-14 years
AHI (Apnea-hyopnea index)
maintained
What are three theories explaining why there is a decrease in AHI after RME in children with OSA?
RME decreases nasal resistance and facilitates the passage of air through the nose
increases the maxillary dental arch, improving the position of the tongue enabling proper sealing of the lips
indirectly increases the oropharyngeal space
True or false… The use of RME in children with OSA appears to be an effective treatment
true
Class 3 malocclusion affects between __-__% of our population
5-15%
Studies have reported that treatment of class 3 malocclusion should be carried out in patients less than ___ years of age to dance the orthopedic effect
10
True or false… there is moderate evidence to show that early treatment with a facemark results in positive improvements in both skeletal and dental changes in the short term. however, there is lack of evidence for the long-term benefits
true
In a study evaluating the affects of extractions on airway, initial and final volumes and the minimal cross-sectional areas [were/were not] statistically significantly different fro the nasopharyngeal, redropalatal, retroglossal, and total airway regions between the extraction and non extraction groups
were not
True or false… dental extractions in conjunction with orthodontic treatment have a negligible effect on the upper airway in adults
true
What are 5 recommendations if auto-transplantation is to take place?
1) extraction should be done ataumatically
2) extra-alveolar time minimized as much as possible
3) Iatrogenic damage at the recipient site should be prevented by minimizing the fitting attempts
4) Donor tooth should be fixed in infra occlusion to prevent postoperative occlusal forces
5) suture splint is advised because this decreases the chance of ankylosis compared with a more rigid splinting system
What can happen if a pt is on bisphosphonates with orthodontic treatment?
can inhibit tooth movement
increases risk of osteonecrosis
What are bisphosphonates used to treat and how do they work?
used to treat bone metabolism disorders (osteoporosis, bone diseases, bone pain from certain cancers)
inhibit bone resorption by osteoclasts
what is the most common bisphosphonate?
fosamax (alendronate)
True or false… you should avoid orthodontic treatment if the patent has taken oral bisphosphonates
not necessarily. you should avoid it if they are on IV bisophosphnotates. But if they are on oral bisphosphonates, treatment may be challenging and you should still watch for signs and symptoms of osteonecrosis.
What are some signs and symptoms of osteonecrosis?
excessive tooth mobility
exposed necrotic bone
non-healing bone after extractions
teeth not moving as they should
True or false.. fixed orthodontic appliances have no power to change the airway volume; this fact is supported in the literature, showing that there is no strong evidence that orthodontic treatment has a significant effect on the pharyngeal airway, even when associated with extractions and despite the changes in incisor angulation and position.
true
Even though the patient is instructed to follow a series of instructions during a lateral ceph scan, changes may still happen possibly caused by…
different breathing stage
swallowing
craniocervical posture
In a study evaluating the long-term comparison of nonextraction and premolar extraction therapy in borderline class 2 patients, how did the pattern of relapse compare between the two groups? How was the patient’s perception of esthetics different ?
Pattern of relapse was essentially identical between the two groups
There was no significant difference in lower incisor crowding and no significant difference in patients’ perception of esthetics.
True or false… there is a single optimal incisor position/angulation that ensures long term stability in class 2 extraction cases.
False. There is a range of positions that will serve the patient
The more the mandible outgrows the maxilla the upper molars and upper incisors will tip ___ and the lower incisors will tip ___. Lower molar anchorage will be ___.
Forward
Lingually
Preserved
For borderline patients, nonextraction treatment produced a significantly more protrusive denture of __mm.
2mm
True or false… the pattern of relapse in extraction or nonextraction of borderline cases is unrelated to the type of treatment
True. Dentoalveolar compensation produced by differential jaw growth following treatment
True or false… there is no evidence that either treatment (ext or non-ext of borderline cases) produce distal displacement of the basal bone of the mandible or its condyle
True. There is no evidence
True or false… with a flatter profile, extraction patients viewed their outcome as a failure compared to nonextraction patients.
False. Despite flatter profile, extraction patients were as likely as the nonextraction patient’s to view their outcome as an improvement
True or false… there has been found to be a slight increase in mandibular intercanine width in extraction patients. On the other hand, intermolar width seems to decrease in both jaws
True
In a study conducted by Herzog et al (2017), the mean change values for the maxillary and mandibular intercanine widths of both extraction and non extraction patients, showed…
No statistically significant difference. However,the mean change values of the intermolar widths were significantly different
The findings of Herzog (2017) indicate that in borderline patients, the choice whether to extract has no impact on the ____of the maxillary and mandibular arches
Intercanine widths
The study by Herzog (2017) found significant differences between treatment groups (ext and non ext) regarding ___ changes. Describe these changes.
Intermolar width
there are smaller arch widths with extraction treatment than non-extraction. This finding can be attributed to the forward movement of the first molars in extraction patients
Herzog (2017) found in borderline cases, the maxillary and mandibular arch perimeter to decrease in the ___ group, whereas the ___ group showed no significant difference in arch perimeter before or after treatment
Extraction
Non-extraction
True or false… Herzog (2017) found the intercanine width of both extraction and nonextraction borderline cases to increase significantly.
True
how does intercanine width increase in extraction treatment? How does the intermolar width decrease?
The distalization of the canines into a wider part of the dental arch during canine retraction.
The intermolar width decreases by anterior movement of the molars during space closure
Overall, in non-ext patients, post-retention of ___ width is more stable than ___width
Intermolar
Intercanine
Extraction treatment leads to decreased maxillary and mandibular ____ when compared with non-ext treatment. Meanwhile, ___ showed no significant difference between the two groups.
Intermolar and perimeter measurements.
Intercanine
In the extraction group (Herzog 2017), ____ increased, ___ showed no significant change, and ___ and ___ decreased
Intercanine width
Maxillary intermolar width
Mandibular intermolar width and arch perimeters
In the non extraction group (Herzog 2017), significant changes of ___ occurred, whereas ___ were maintained.
All arch-width measurements
Arch perimeters
The data from Gianelly 2003 indicates that ____ are not the expected consequence of extraction treatment. Therefore, the esthetically compromising effect of ___ on smiles is not a systematic outcome of extraction treatment.
Narrow dental arches
Narrow dental arches
According to a study by Bowman, the two panels both rated ___ treatment as having little esthetic effect throughout the full range of pretreatment profiles. ____ had the potential to improve or worsen the profile depending on the patient’s initial protrusion
Nonextraction
Premolar extraction
In Bowman’s study, extraction treatment has a ___% probability of producing an improvement in facial esthetics, despite producing an average of __mm less lip protrusion than nonextraction. Nonextraction has only a ___% likelihood of improving facial esthetics.
50-60%
1.8mm
30-50%
The esthetic effect of treatment on the facial profile is a function of ___, ___, and ___
The type of treatment
Initial protrusion of the profile
Background of the observer
In a study by Bowman, profiles of extraction patients that initially had lower lip protrusion ___ behind the E-line were worsened by treatment
2-3mm
What are the 3 leading reasons for extractions in orthodontics in order?
Crowding
Incisor protrusion
Profile improvement
Studies have indicated that __% of interproximal enamel can be safely removed.
50%
True or false… males have more interproximal enamel than females
False. There is no statistically significant difference in mesial or distal enamel thickness between sexes
With the exception of the ___, ___ enamel demonstrates significantly greater enamel thickness than ___
Second premolar
Distal
Mesial
Name three potential iatrogenic effects of IPR
Increased incidence of caries
Temperature sensitivity
Periodontal disease
(However these effects may not be seen as frequent in anterior)
IPR may be indicated in individuals with… (4 things)
1) good OH
2) class 1 arch length discrepancies with orthognathic profiles
3) minor class 2 dental malocclusions (particularly non-growing pts)
4) Bolton tooth size discrepancies
IPR is well suited for patients with arch discrepancies less than the size of ___
Two premolars
Even patients with the thinnest enamel could expect to gain __mm with 50% IPR in 8 posterior contacts
7mm
Mandibular incisor relapse appears to be minimal when nonextraction treatment is used with ____
Palatal expansion
Premolar extraction reduces soft and hard tissue convexity by ___mm whereas nonextraction therapy has little effect. In general, _____ changes (including an additional convexity reduction) are about the same in both groups.
2-3mm
Post-treatment
When growth is finished, clear-cut [extraction/nonextraction]patietns tend to have “flatter” profiles than do ___ patients who present with ____
Nonextraction
Premolar extraction
Significant crowding and spacing
Pre-and post-treatment tooth movements tend to be related to the pattern of ___; some forms of relapse therefore, may be a dentoalveolar compensation for residual posttreatment growth
Jaw-growth
A study by Little found that average treatment time for serial extraction was 12 months vs nearly twice that time for ____
Late extraction
This suggests serial extraction may require more observation visits but fewer months of active treatment
What are the three clinical implications discussed by Little regarding serial extractions?
1) possibly improved periodontal health if anteriors were not allowed to crowd
2) reduced treatment time but patients did require supervision during the mixed dentition pre-appliance stage
3) Often serial extraction procedures were required prior to first premolar extraction in order to guide the developing dentition vs a single extraction surgery in the late extraction group
There is ___ anchorage needed for four premolar extraction treatment of class 2 vs two premolar
2x more
In a study by Janson, treatment with 2-PM extraction provided better occlusal success rates compared to 4-M due to what 4 factors?
1) final TPI (treatment priority index) was significantly smaller and change during tx was significantly greater
2) Final bilateral canine AP discrepancy was significantly smaller and change during tx was significantly greater
3) Final overjet was significantly smaller
4) final overbite was significantly smaller and change during tx was significantly greater
Describe the differences in ABO scores observed in patients treated with or without extractions
There was no statistically significant difference
Describe the differences in extraction vs nonextraction treatment that were found between the scores of the 8 ABO variables.
No statistically significant differences were found
The variable of ___ received the poorest grade and appears to complicate orthodontic treatment the most
Buccolingual inclination, through which torque control of the posterior segment is assessed,
True or false… class 1 patients treated with or without extractions of 4 first premolars have similar probabilities of passing the ABO exam
True
What was concluding in a study comparing linear and angular measurements on panos taken at different times (Stramotas)?
Comparing linear and angular measurements on panos taken at different times is sufficiently accurate for measuring changes in root length and root parallelism, to assess sites for implant location, and to measure angulation of developing third molars (provided the occlusal plane is kept at similar angulation and not tilted>10degrees)
Accurate measurement of structures on panoramic images is possible, provided sufficient care is taken with head positioning
Teeth with abnormally shaped ___ have a greater risk of root resorption
Apices
What are the first and second most common resorbed roots in orthodontic treatment?
Maxillary lateral incisors: most common resorbed teeth, also highest rate of dilaceration
Maxillary central incisors: second most common resorbed teeth, highest incidence of point teeth
True or false.. it is more difficult to assess root shape on a panoramic film compared to peri-apical films
True
root that had abnormal shape on PA were rated normal shape on pano
Overall apical resorption shows to be [greater/lesser]on panoramic films compared to periapical films. Why?
Greater
Severity of root resorption may be over exaggerated due to patient positioning and focal trough aligned with maxillary dentition.
Periapical films provide a more detailed view of alveolar bone and root.
If initial and final panoramic films are used to assess the amount root resorption, it may be exaggerated by ___% or more. ____ are especially vulnerable to distortion
20%
Mandibular incisors
Clinicians should check panoramic films carefully and order PA films if roots cannot be visualized. Also receommend PA films on patients with higher risk of root resorption or bone loss
The most frequent errors occurring in panoramic radiography occur because of ___. Describe the frequency of these errors.
Patient positioning
14% chin too low
4% head tilted
4% head turned
1% chin too high
The clinical assessment of ____ tooth angulation with panoramic radiography should be approached with extreme caution, with an understanding in of the inherent image distortions that are further complicated by the potential for aberrant head positioning
Mesiodistal
Panoramic radiography visualizes the ___ and ___ of the TMJ and does not visualize the ___. A study by Epstein confirms that panos can show ___-___ bony abnormalities. However, they did not provide information that influenced ___ in the majority of cases
Lateral slope and central positions
Articular eminence and fossa
Moderate-severe
Diagnosis/patient management
The presence of atheromatous plaque in the carotid artery of clinically asympotmatic individuals is often associated with the later development of ___, __, and ___
Cerebrovascular disease
Coronary artery disease
Death
41% of patients with carotid calcifications had a ___% death rate during an average 3.6 year follow up
15%
Name 8 factors to consider when evaluating buccal-bone thickness in CBCT scans
1) voxel size
2) spatial resolution
3) partial volume averaging
4) noise
5) gray scale
6) tooth rotations
7) RAP (regionally acceletory phenomenon)
8) statistical power
What are the most common voxel sizes used for routine orthodontic scans? What spatial resolution does this allow? Can this be used to adequately visualize thin bone?
0.3mm and 0.4mm. Rendering an average spatial resolution of 0.7mm which is no adequate to properly visualize thin bone.
In a CBCT, scatter levels increase as the size of ___ increases.
Field of view
Current CBCT systems range from __ to __ bit gray scale, but the human eye cannot distinguish past ___bit. What should be used when evaluating buccal bone on a CBCT?
12-16
10
Highest available grey scale
How should you account for tooth rotations when evaluating buccal bone thickness in a CBCT?
Make multiple measurements around the tooth and average them for a more accurate representation of bone support regardless of tooth rotations
Describe RAP (regionally accelatory phenomenon) and its affect on CBCT scans.
It is a tissue reaction to a noxious stimulus that increases the healing capacities of the affected tissues. This occurs with orthodontic tooth movement when alveolar bone undergoes constant bone turnover and reduces the density of the active bone.
Since CBCT scans identify an object by its density, bone undergoing RAP would appear more radiolucent
How long should you wait after orthodontic treatment to evaluate buccal bone thickness with a CBCT? Why?
At least one year
RAP takes 6-24 months to fully subside after the end of tooth movement. RAP can affect the CBCT scanner’s ability to accurately depict the bone.
Name 6 recommendations when evaluating buccal bone thickness in a CBCT.
1) Use a smaller voxel size than standard orthodontic voxel size (<0.3mm)
2) reduce noise by using the smallest FOV possible and removing metal brackets/bands
3) Increase scan time
4) use a 16-bit sensor for the best gray scale
5) Factor in tooth rotations (average multiple bone thicknesses)
6) wait at least one year post-treatment to minimize influence of RAP
True or false… CBCT scans for routine orthodontic purposes are adequate to accurately evaluate buccal bone changes
False
Labial impatient of canines occurs in about __% of patients with the most common treatment being ___ and ___
Excisional gingivectomy
Apically positioned flap
Although, closed-eruption technique is believed by some to be superior especially for teeth that are impacted high above the mucogingival jnction or deep within the alveolus
A ___flap is used in the apically positioned flap technique of canine exposure. What occurs after the flap?
Split-thickness
Once reflected, bone that was covering the enamel is removed until 2/3rd of the crown is exposed and the CT follicle is curettes from the periphery of the exposed portion of the crown. Then surgical dressing is placed over enamel to ensure tissue does not grow over the enamel. Then surgical dressing is removed and orthodontist bonds attachment 2 weeks after surgery
Labially impacted maxillary anterior teeth uncovered by ___ have more unesthetic sequalae than those uncovered by ___
Apically positioned flap
Closed-eruption technique
What are four negative esthetic effects when an apically positioned flap is used to expose a canine?
Increased crown length
Increased width of attached tissue
Gingival scarring
Intrusive relapse
Closed-eruption technique is typically superior to the apically positioned, flap, however if a tooth requires ___ or is displaced ____, an apically positioned flap may be the best choice.
More attached gingiva
Lateral to the edentulous area
A study by Vermette (1995) found a significant number of ___ relapse cases within the apical positioned flap cases that were not seen in the closed-eruption groups. What might be an explanation?
Vertical
Once the flap is positioned apically, the gingiva heals to the new positions, which could be far above the mucogingival junction. When the teeth are erupted into occlusion by orthodontic forces the gingival tissue will stretch , which causes complications for fighting relapse
A study by Vermette (1995) found that for the ____, the gingival margin was located significantly more apical, the clinical crowns were longer, more attachment was lost on the facial surface, and more bone was lost on the mesial, facial, and distal surfaces.
Apically positioned flap
Describe the two methods of surgical exposure for palatally impacted canines.
Open exposure: traction is placed after the canine erupts freely into the palate
Closed exposure: placement of an auxiliary attachement, followed by traction of the canine with ortho forces
What are the advantages of open exposure of palatally impacted canines?
Fewer subsequent re-exposures
Shorter treatment time
Improved hygiene during treatment
A study by Schmidt concluded that treating palatally impacted maxillary canines with ____, ___, and ___ has minimal effects on the periodontist
open surgical exposure
natural eruption of the canine
orthodontic alignment
The study conducted by Schmidt found that roots of impacted canine and the adjacent lateral incisor were ____ than those of the contralateral control teeth, and no significant ___ changes were identified.
slightly shorter
pulpal
True or false… in the study by Schmidt, visual differences were not apparent in the previously impacted tooth when compared with the contralateral control canine
false. visual differences were present
___ are the second most commonly impacted permanent tooth. 1/3rd are located ___, and 2/3rds are located ___
maxillary canines
labially or within the alveolus
palatally
What are two options to attempt to enhance eruption of labially impacted canines without surgical uncovering?
extraction of primary canine (8-9 years old)
mechanically open space with orthodontics
What are the three techniques for uncovering a labially impacted maxillary canine?
excisional uncovering
apically positioned flap
closed eruption techniques
What are four criteria to consider when determining the method of uncovering of a labially impacted canine?
labiolingual position of impacted canine
vertical position of impacted canine relative to mucogingival junction
amount of gingiva in the impacted canine area
mesiodistal position of the impacted canine
If a maxillary canine is impacted labially, any of the three exposure techniques can be used, however if the canine is located in the center of the alveolus, only the ___ technique can be used. Why?
closed eruption technique
the excisional approach and apically positioned flap would need extensive bone removal
Which exposure technique must be used if an impacted canine crown is apical to the MGJ? Why?
closed eruption technique
Excisional technique would be inappropriate because there would be no gingiva over the labial surface after it has erupted. apically positioned flap would be inappropriate because crown instability and retrusion relapse after treatment
If the crown of an impacted maxillary canine is mesial and over the lateral root, you should use the __ technique
apically positioned flap
Why should you avoid mechanics that draw an impacted canine labially?
it could cause dehiscence and labial recession
If the permanent canine was positioned over the ___ but not past the ___, self correction occurred with high predictability if primary canines were removed
root of the lateral incisor
mesial surface of the root
If an impacted canine, in which surgical exposure has been performed, does not appear to be moving, what could be the cause?
problem is usually insufficient bone removal over impacted canine crown
impacted canine crowns are often in contact with the lingual surfaces of the central and lateral incisor roots
actual ankylosis of maxillary canines is low likelihood
When impacted canines are dragged across the lingual surface of lateral incisor roots, what may occur?
root resorption of lateral and canine
bone levels of distal of lateral and mesial of canine were more apical compared to contralateral non impacted teeth
How can treatment time, and periodontal and esthetic results be improved with palatal impaction of canines?
early uncovering using a full-thickness mucoperiosteal flap and allow canines to erupt on their own to the level of the occlusal plane in 6-8 months. Then a bracket is placed and the canine is brought into the arch
Maxillary canine impaction occurs in __% of the population. it occurs twice as often in ___vs ___, ___ vs ___, and ___ vs ___. There is a 2.4x increase chance of palatally impacted canines when missing ___
2%
females vs males
maxilla vs mandible
palatal vs labial
lateral incisors
Only ___% of labially displaced canines have sufficient space for eruption vs ___% of palatal canines
17%
85%
This shows that arch length discrepancy is the primary factor for labial canines, yet the etiology of palatally impacted canines is not known
What are some palatally impacted canine theories?
Guidance theory: canine guidance is guided along the root of lateral incisor, if root is absence or malformed, canine will not erupt.
Genetic theory:
What are the sequelae of impacted canines?
usually asymptomatic
can cause migration of neighboring teeth and loss of arch length
root resorption of surrounding teeth
increased risk of cysts and infection
What are 5 clinical signs of a palatally impacted canine?
1) delayed eruption
2) over-retention of primary canine
3) absence of labial bulge (around 9-10 years old)
4) presence of palatal bulge
5) distal crown tipping of lateral incisor
Extracting primary canine before patient is 11 years old will result in ___% success rate if crown is distal to midline of lateral root and ___% if crown is mesial to midline of lateral root. Probably of successful eruption decreases as ___ and ___ increase
91%
64%
horizontal angulation and overlap
What are the three steps to bring in an impacted canine?
1) create space in arch for impacted canine
2) Surgically expose the tooth
3) apply force to erupt the tooth (avoid contacts with roots of other teeth)
What is the simplest way to reduce the frequency of canine impaction?
timely extraction of primary canines
What are some less common etiologies behind impacted canines?
1) supernumerary tooth or odontomas
2) cysts
3) hx of trauma
___-___% of canine impaction cases are unilateral
60-75%
This gives question to the genetic theory or canine impaction because you would expect more bilateral cases. Also identical twins were shown to have same incidence of ectopic canines as fraternal twins, opposing the genetic theory. C
True or false… the eruption of the canine is strongly influenced by environmental factors
true
although hereditary effects may be associated, genetics shouldn’t be warranted as the underlying cause of canine impaction
A study by Armi (2011) showed that maintenance or improvement of the perimeter of the upper arch as a measure to intercept palatal displacement of maxillary canines is ____in preventing impaction of palatally displaced canines
effective
True or false.. the use of RME and headgear in palatally displaced canine cases increases the success rate of eruption of the canine
true
almost three times more than in untreated controls
True or false.. the prediction of the probability of canine impaction based on CBCT is excellent
true
What are the strongest predictors based on CBCT radiographs to identify to probably of impaction?
canine angulation to the lateral incisor on the coronal view
canine cusp tip to the occlusal plane on the sagittal view
canine crown position
Describe the radiographic appearance of teeth undergoing root resorption. How do they look after termination of active orthodontic therapy?
Rough, jagged and notched root contours. Widened PDL space that accentuated the rough appearance.
Jagged edges become smooth. Sharply pointed root ends rounded with time
Does root resorption continue even after the orthodontic appliance is removed ?
no
What are the two types of internal root resorption?
apical
intraradicular (more rare)
What are the two types of intradicular internal root resorption?
inflammatory resorption
replacement resorption
What are the three requirements for internal root resorption to occur?
Damage of odontoblast layer in plural canal wall
bacterial stimulus
viable blood supply apical to resorptive lesion
What is the difference between internal inflammatory resorption and internal replacement resorption?
In inflammatory resorption the resorptive space is filled with granulation tissue
in replacement resorption the resorptive space is filled with metaplastic tissue that may resemble bone or cementum
What is the treatment that should be done with teeth diagnosed with internal root resorption?
Root canal treatment
early detection and intervention improves prognosis
What causes the resorption in internal root resorption?
clastic cell action (odontoclasts)
If the internal root resorption is located in the coronal part of the canal ___ can be observed.
a pink spot in the crown
What are the therapeutic options for treating teeth with internal root resorption?
1) monitor (in absence of infectious signs and symptoms)
2) RCT (use MTA if perforation has occurred)
3) retrograde apical treatment
4) extraction
A study by Kurol et al (1998) found that there may be a relationship between root resorption and ___ in the PDL
hyalinized areas
Resorption cavities are seen close to the over-compressed zones. But, about half of the hyalinzed areas were NOT associated with root surface resorptions
Generally, it is believed that hyalinized zones are due to ___ of the PDL. Even with initially _____ hyalinization and root resorption must be expected.
over-compression
light orthodontic forces below 50gm
What is inflammatory external root resorption?
The intermediate cementum layer that caps dentinal tubules will resorb the inflammatory response is large or there is serious trauma.
if pulp is infected, bacterial byproducts can become the source of ongoing increased root resorption
can be arrested by endodontic therapy
More frequent in younger implanted teeth
Another term for replacement resorption is ___
ankylosis
Describe the etiology of replacement resorption
extensive damage to the PDL will cause PDL to become nectroic
Alveolar bone will replace the attachment and resorb the root and will result in dentin fused to bone
clinically, ankylosis will have a metallic sound on percussion and a moth-eaten look radiographically
true or false… external root resorption can occur from pulp necrosis and periradicular pathosis
true
External resorption from pressure in the PDL can occur without orthodontic treatment most frequently in which areas?
maxillary laterals by canines
mandibular second molars from the third molars
What is cervical resorption? What causes it?
A progressive external inflammatory resorption that occurs just below the epithelial attachment or more apical on the root surface where damage to the PDL or cementum has occurred
Can be caused by: orthodontics, trauma, internal bleaching, periodontal treatment, orthographic or dentoalveoalr surgery, and idiopathic causes
if resorption infiltrates the crown, the cervical coronal enamel may appear pink in color
Some degree of orthodontically induced external root resorption is expected to occur in __% of patients
80%
A ___mm loss of root length due to OIERR is biomechanically equivalent to ___mm loss of crestal alveolar bone loss
3mm
1mm
Severe OIERR is considered to be a loss of ___mm or more than ___ of the overall root length.. It is estimated to affect up to ___% of orthodontically treated patients
> 4mm
1/3rd
15%
[continuous/interrupted] forces induce more OIERR than [continuous/interrupted] no matter the force level
continuous
interrupted
Which causes more root resorption?
Heavy or light forces?
Intrusive or extrusive forces?
Short or long treatment duration?
What are the effects of bracket prescription, wire sequence, and ligation method?
Heavy
intrusive
long
bracket prescription, wire sequence, and ligation method had no differences in OIERR
What are the three treatment options for congenitally missing lateral incisors?
Canine substitution
single-tooth implants
tooth-supported restorations (full coverage FPD, cantilevered FPD, Marylin bridge)
In order to treat a patient with congenitally missing lateral incisors with canine substitution, the patient ideally has….
small canines that are the same shade as the central incisors
nice profile
class 2 dental relationship
no crowding in the dental arch
Greater bucco-lingual alveolar width for implant placement of lateral incisors can be established if….
the permanent canine erupts in the lateral incisor position and then is moved distally into place
otherwise the edentulous site is typically deficient
Implant placement in a narrow ridge requires ____ to prevent dehiscence and results in ____
deeper placement
thin facial bone which can lead to a show-through of the implant body/abutment (new zirconia implant abutments may help so the implant isn’t as noticeable)
Alveolar ridge augmentation is needed for a stable overlying esthetic soft tissue framework
Bone loss near an implant is worse if the implant to tooth distance is
1.5mm
PAs of the edentulous area must be taken before removing orthodontic appliances to confirm ideal root position and adequate spacing for implant placement
The timing of implant placement for missing lateral incisor is based on the patient’s facial growth. If it is placed before growth is completed it can lead to periodontal, occlusal, and esthetic problems. It can typically be based at age __ for males, and ___ for females. describe the most predictable way to monitor facial growth for implant placement.
20-21 years
16-17 years
Take serial cephs every 6 months to year apart. implant can be placed if 2 sequential radiographs show no growth
What could happen if a patient uses a flipper for too long instead of getting an implant for their missing lateral incisor?
The central incisor and canine roots can converge overtime
A resin-bonded FPD (Marylin bridge) is the most conservative approach of the tooth-supported restorations for replacing a missing lateral incisor. What are three contraindications for this method? Describe the ideal patient.
Contraindications:
1) deep bite
2) proclined teeth
3) mobility of abutment teeth
Ideal:
1) non-bruxer
2) upright incisors
3) immobile abutment teeth
4) shallow overbite
A cantilevered FPD to replace a missing lateral incisor is more predictable than a resin-bonded FPD. Why is the ___ the ideal abutment tooth?
What is the key to long-term success using this approach?
Canine
because of its root length and crown dimensions
removing all excursive contacts
What are the two types of malocclusion that permit canine substitution?
Class 2 with no mandibular crowding
class 1 with severe mandibular crowding warranting extractions
Naturally, the canine is ___ shades darker than the lateral incisor
1-2
you can individually bleach the canine or veneer it to better match the adjacent teeth
What are four characteristics of an ideal canine to be used for lateral incisor substitution?
1) same color as central incisor
2) is narrow at the CEJ BL and MD
3) has relatively flat labial surface
4) has narrow crown width BL
You should position the gingival margin of the canine slightly ___ to the central incisor gingival margin to help camouflage the substituted canine. therefore, you should place the brackets according to the ___ rather than the ___
incisal
gingival margin height
incisal edge/cusp tip
In canine substitution, as the canine erupts, periodic equilibration during alignment stage is necessary. why?
A thicker portion of the canine will contact the mandibular incisors
___% of wisdom teeth either fail to erupt or only partially erupt
24%
more common in lower jaw
True or false… all third molars should be extracted prophylactically
false.
there is insufficient evidence to either support the removal or retention of asymptomatic, disease-free impacted wisdom teeth
What are the main soft tissue and hard tissue conditions associated with third molars that would necessitate their removal?
pericornitis and infection
periodontal disease
dental caries
odontogenic cysts and tumors
There is a higher likelihood of pericornitis in ___ positioned lower third molars at or near the level of the occlusal plane and in ___ cases with ___ positioned third molars
vertically
ortho-treated
mesioangular
True or false.. it has been shown that periodontal status of second molar improves over time after third molar removal
true
True or false… third molar sites commonly harbor microbial flora known to be associated with periodontal disease, and evidence suggests that third molar sites may first be affected by periodontitis that moves to more anterior locations overtime
true
True or false… remineralizing capacity of fluoride is generally accepted, but evidence is insufficient to support effectiveness of remineralization of post-ortho WSLs
true
True or false… studies have shown that CPP-ACP can promote remineralization of subsurface lesions, but current evidence is insufficient to prove a clinical benefit on post-ortho WSLs
true
What are 8 guidelines (Kokich 1997) to assist clinicians when planning interdisciplinary treatment. If orthodontists and restorative dentists do these things, the esthetic and occlusal outcome of their combined efforts will be greatly enhanced.
1) establish realistic objectives
2) create a diagnostic set-up
3) determine the sequence of treatment
4) build-up malformed teeth
5) position teeth to facilitate restorative treatment
6) evaluate gingival esthetics
7) take progress radiographs
8) interact during finishing
The first step in any type of dental therapy is to ___.
establish treatment objectives
It is impossible to achieve the correct end result if the appropriate goals or objectives have not been identified before treatment
____ treatment objectives may not be appropriate for the orthodontic-restorative patient. for these types of patients, it is important to…
Idealistic
establish realistic, not idealistic treatment objectives
Realistic treatment objectives fall into three categories. what are they?
economically realistic
occlusally realistic
restoratively realistic
A ___ is mandatory for any patients who are missing multiple permanent teeth and who will require a combination of orthodontics and restorative dentistry
diagnostic was set-up
A team of specialists must not only establish a realistic plan of treatment but they should also…
determine the sequence of interaction between different specialists
This is a critical step that should occur before the initiation of therapy. A copy of the sequence should be given to each of the participating dentists.
What are two common situations in which teeth must be built-up before, during, or after orthodontic therapy?
retained primary teeth
peg-shaped lateral incisors
With retained primary, mandibular central incisors, maxillary lateral incisors, and maxillary canines, what should be done if these teeth are to be retained until replacement with implant?
they should be built-up mesiodistally to preserve space for the implant.
It is often necessary to create a diagnostic wax-up to simulate the correct width of the composite restoration. some of these primary teeth can be retained indefinitely
If sufficient space exists to do a composite restoration of a peg lateral before orthodontic treatment, should it be performed before or after orthodontic treatment?
before
However, in most situations, there is insufficient space to restore the malformed lateral incisors. therefore, orthodontics is often necessary to create space to build up peg laterals
If a patient has a normal lateral incisor on one side, but a peg lateral on the other, how much space should be created for the restoration of the peg lateral?
A little extra space than the normal lateral incisor, because it will allow the restorative dentist to contour and polish the interproximal surfaces of the restoration.
The ___ surfaces of central and lateral incisors are more contoured or convex. Therefore, the peg-shaped lateral incisor should be positioned ____ during orthodontic treatment for the best composite restoration
distal
nearer the central incisor than the canine
where should the lateral incisor be positioned in the buccolingual orientations for the restoration with a crown? What about a porcelain veneer?
center of the ridge BL (this will avoid additional tooth preparation on the lingual of the lateral)
Further lingually to contact the mandibular incisor in centric occlusion. (This will allow sufficient space on the labial to construct both the temporary composite build-up and the eventual porcelain laminate)
where should a peg lateral be positioned incisogingivally for restoration?
the relationship is determined by the position of the gingival margins
When making the decision to restore a peg-lateral, several concerns must be addressed. what are 3 concerns?
1) cervical portion of the peg lateral is usually narrower MD (restoration will be over-contoured)
2) life of the restoration (using a veneer instead of a crown would increase the longevity of the tooth because it will likely need to be restored multiple times throughout life)
3) esthetics.
Periodontal surgery can be performed to improve the length of clinically short crowns. If the bone is located near the CEJ, ___ will be necessary. If the bone is ___mm away from the CEJ, a ___ is sufficient.
osseous surgery
1-2mm
simple gingivectomy
If a conventional FPD is going to be used to replace a missing lateral incisor, the orthodontist should create ___ of overjet at the end of treatment
0.5mm - 0.75mm
How should you treat an adult patient with worn and shortened incisors?
intrude the incisors by placing the brackets slightly more incisally.
posterior teeth will be anchors to facilitate intrusion of the incisors and will lead to an open bite (which is what you want)
After the appropriate gingival margin relationships have been achieved 1) remove brackets, 2) restore incisal edges, 3) replace brackets and complete orthodontic treatment
Why should you intrude incisors that have wear on the lingual surfaces and which are planned to have crowns?
to create space for restorations
The gingival margins of the lateral incisors should be __ ___ to the central incisor. the canine gingival margins should match the central incisors
0.5mm
incisal
If teeth have __mm of sulcular depth and the gingival margins are at different levels, the patient should be referred to a periodontist to perform gingival surgery [before/after] bracket removal
> 1mm
before
As the central incisor and canine are pushed apart, what may occur which would make it impossible to place an implant for the missing lateral incisor?
the apices of the roots converge. Therefore, radiographs must be taken to ensure the roots have moved out of the way
If the patient will require restorations after orthodontics, when should the orthodontist send the patient to the restorative dentist?
during the final 6 months of treatment
True or false… orthodontic space closure of missing lateral incisor space is reasonably stable and better accepted by patients than prophetic replacements (not including implants).
true
pts with prosethsic replacement tend to have impaired periodontal health with acculumuation of plaque and gingivitis.
Does canine substitution impair TMJ function
no
What is the H-line and how is it measured?
Harmony line, created by Holdaway
measured from most prominent part of upper lip to the soft tissue pogonion.
Used to evaluate soft tissue protrusion of the lower face, including the lips. And the upper and lower lip sulci
Useful because it does not depend on the size of the nose (which is highly variable)
The interlabial gap is affected by what four things?
lip length
protrusion of the teeth
tonicity of the lips
skeletal (vertical) relationships
how do you determine the prognosis of impacted maxillary canines regarding vertical position?
best - tip of canine at CEJ of adjacent teeth
Worst - tip of canine less than 1/3 from apex of adjacent teeth
How do you determine the prognosis of impacted maxillary canines regarding horizontal position?
best - less than half of the distance across the root of the lateral
worst - more than half the distance across the lateral
How do you determine the prognosis of impacted maxillary canines regarding angulation?
best - less than 30 degrees
worst - more than 45 degrees
How do you determine the prognosis of impacted maxillary canines regarding crowding?
best - mild/moderate spacing
worst - crowding in anterior leaving no room to move teeth out of the way of erupting canine
how do you determine the prognosis of impacted maxillary canines regarding the age of the patient?
best - less than 12 years old
worst - greater than 18 years old
What percentage (range ) of patients have some sort of radiographic pathology?
4-6%
What are the big 3 reasons to extract?
crowding
proclination of incisors
improve profile
What are some secondary reasons to extract?
- camouflage tx
- preparation for surgery
- attempt to deepen bite
- questionable prognosis of teeth
- asymmetric extraction to correct midlines or if there are missing teeth
patients with thick lips (___) have minimal changes to profile due to extractions. patients with thin lips (___) have significant changes to profile with extractions.
18+mm
12-mm
Statural growth [proceeds/follows] maxillary and mandibular growth by about ___ months
proceeds
6
True or false… it is difficult to predict growth for an individual but you can predict a population pretty well with some standard deviations
true
True or false… by the time girls’ permanent teeth are in they are typically past their peak growth
true
boys will typically have all their permanent teeth in when they are going through peak growth. Therefore, it is typically easier to do growth modification on boys than girls.
When is the most efficient time to treat transverse or maxilla AP deficiency?
pre-peak growth
when is the most efficient time to treat class 2?
right at or slightly before peak growth
True or false… all peak growth velocity occurs between C3 and C4
false. although most people’s peak growth velocity occurs here, for some people it occurs between C4-C5
True or false… early class 2 growth modification is not effective at all
false. it is effective in that it does correct the class 2. but it is not efficient because that improvement will not last. It is not any more effective than just doing it later during comprehensive treatment during adolescent growth spurt. This means early class 2 treatment can still be used in special indications such as trauma or bullying
True or false… you should only expand in phase 1 if the patient has a crossbite with a functional shift
false.. if they have a deficient maxilla (lower molars are tipped lingually and walla ridges are tight), expansion is done much easier in phase 1 when patient is young. Additionally, if you burn off the primary roots or get recession of gingiva of primary teeth, it doesn’t matter
True or false… with class 2, but not class 3 molar finish you must use 0-offset bracket/bands
false. you have to use 0-offset for BOTH class 2 or class3 molar finish
What is the “biggest struggle” with 2 upper premolar extractions for class 2 camoflauge treatment according to Minick?
biggest struggle with 2 premolar extractions is keeping the torque with the upper incisors and not let too much crowding in the mandible cause the lower incisors to flare. If you upright the upper incisors as you retract them and let the lower incisors flare you will run out of functional overjet and still have spaces to close. You may think you have a bolton discrepancy, but you don’t.
True or false… it is much easier to maintain torque than to regain it
true
A 19x25 wire in a 22 slot will cause you to lose torque when retracting upper incisors
With Dr. Minick if you see an impacted canine, you should take a CBCT. Why?
You can’t really tell where the canine is or its angulation from pano or PAs and you certainly can’t tell the damage that has already been done. most laterals and 10% of centrals already show damage in a CBCT
what are the max limits of an enlarged sella. if it is larger than these measurements then it is concerning and should be evaluated.
AP = 16mm
Depth = 12mm
what is a sponylolisthesis?
a “step” between the vertebrae. can lead to hernia of disks
looking at a hand-wrist radiograph when does female peak statural growth occur?
what about males?
female SMI = 5
male SMI = 6
Looking at a hand-wrist radiograph when does female peak jaw growth occur? what about males?
female SMI = 6
male SMI = 7
Skeletal changes require what three things?
1) precursor mesenchymal stem cells
2) capability for growth factor expression
3) local environmental factors (ortho tx)
strongly consider extracting primary canines if permanent canines are impacted (but its success depends on the angulation and horizontal overlap of the canine). ___% successful if canine tip is distal to middle of lateral root. ___% successful if canine tip is mesial to the middle of lateral root.
91%
64%
Headgear with our without RME significantly increases the rate of palatal canine eruption by ___
3x
