Ortho Flashcards
When will a flush terminal plane primary occlusion become class one if it does NOT have a primate space?
during the late mesial shift
What is the incidence of supernumerary teeth?
3.6% (10:1 more common in maxilla, boys more than girls)
Describe flush terminal plane
the distal surfaces of primary second molars are flush
What is the incidence of congenitally missing second molars and maxillary lateral incisors?
4% - most frequent besides third molars
Incidence of supernumerary teeth is 3.6%
Mesial step occlusal - 15% incidence, usually results in Class ___ occlusion?
one
Marie-Sainton syndrome: cleidocranial dysplasia or osteodentin dysplasia or mutational dysostosis: large fontanelles; SMALL nasal sinus; no clavicles; maintain the primary dentition until age 15. MAny supernumerary teeth. What type of bone malformation occurred?
Intramembranous ossification disorder (endochondrial = achondroplasia)
What are the leeway spaces for maxilla and mandible?
maxilla: 0.9 mm per quad
mandible: 1.7 mm per quad
If the canine overlaps NOT beyond the lateral incisor’s midline long axis, successful repositioning is approximate ___%?
85-90%
If the canine overalps beyond the lateral incisor’s long axis, what is the % chance of successful repositioning?
60%
Consult the orthodontist BEFORE removing lower canines, especially if patient is _______________
brachyfacial/a deep bite case
What type of maxillas are associated with digit habits, mouth breathing patterns, and primary canine interference (canines are vertically oriented)
Constricted maxillas
Define class 2 div 1:
maxillary anterior teeth are (1) PROCLINED and a (2) large overjet is present
What appliance is being described: fixed palatal arch wire from E’s with distalization elastics to bonded button on first molar to treat ectopical eruption of 6 year molars
Haltermann appliance
Erupting premolars will move through __ mm of bone in 4-5 months
1 mm
What is an ideal primary dentition occlusion?
FTP or mesial step with class one canines
Baume type one arch with generalized spacing
2mm OJ, 2 mm OB (30-50% OB)
What is the goal of maxillary expansion?
correct transverse discrepancy and eliminate functional shift
Average FMA?
26 degrees
Primary spacing affects crowding outcomes predictors into the mixed dentition. What % chance of crowding with crowded primary teeth?
100% with incisor crowding
What is the treatment for an anterior open bite with extra oral habit?
4-6 yo - try a rewards program
8-10 yo: crib appliance for 6 months
T/F: Loss of a primary molar before 7 years results in delayed eruption of premolars. Loss of a primary molar after 7 years will lead to an accelerated eruption of the premolar
True
T/F: Most of the space loss occurs in the first 6 months after an extraction. Erupting premolars will move through 1 mm of bone in 4-5 months
True
What class relationship can occur from distal end or end-on-end primary relationship?
Class II
What is the % chance of incisor crowding when spacing is less than 3 mm?
20%
Mixed dentition analysis: Moyers, Nance, and Tanaka Johnson all use what measurement as the standard?
mesiodistal width of the mandibular permanent incisors
What is the priority for space management for brachyfacial/deep bite patients?
prioritize arch development/expansion
Dolichofacial/open bite - extraction is more likely
Average IMPA?
90-94 degrees
What is the formula for the mandible using Tanaka Johnson?
(1/2)x(combined mesiodistal width of all 4 mandibular incisors+10.5)
In any mixed dentition analysis, the most careful estimate will only be accurate within __ mm
2 mm
What is more common, labial or palatal displacement of the canines?
MEsiolabial displacement of #6,11 affects up to 10% of children. Palatal displacement of maxillary canines is much less common affecting only 1-2% of the population with a predilection for females (3:1 - palatal displacement of 6,11)
What % of pediatric primary dentitions have non-spaced dentitions?
1/3 (Baume type II)
Note: Spacing in arches is related to BASAL ARCH SIZE rather than tooth mass differences
What % of children have bilateral posterior crossbite?
2-3%
What % of children with a non-nutritive sucking habit will discontinue between the ages of 24-48 months of age?
50%. Digit habits can last longer than pacifier habits, both produced similar effects if they persist beyond 4 years of age
What is typically the last tooth to erupt in the primary dentition
Upper second molars: A, J
What is the primate space?
Distal of lower canines to mesial of mand first primary molar
Mesial of upper canines to distal of lateral incisor
What is the priority for space management for dolichofacial/open bite patients?
Extraction is more likely
brachyfacial/deep bite patients: prioritize arch development/expansion
BQ: Ectopic eruption of first molars. incidence?
2-3% in maxillary arch, rare in mandibular arch. 66% self correct except in CLP where only 22% self correct
What are some treatment considerations of ectopic eruption of first permanent molars?
1) Elastic separators
2) Fixed palatal arch wire from E’s with distalization elastics to bonded button on first molar (Haltermann appliance)
75% of occlusal relationships in the primary dentition are what?
Flush terminal plane, most shift to class one but some shift to class two
What is the maxillary leeway space?
0.9 mm per quadrant (1.8 mm total)
Eruption: 6-1-2-4-5-3-7
What terms describe counter-clockwise rotation of the face?
Hypodivergent/Brachyfacial
What is the combined mesiodistal width of primary canines, first, and second molars?
Leeway space of Nance: 1.5 mm total maxilla; 1.5 mm both sides mandible
Digit habits can last longer than pacifier habits, both produced similar effects if they persist beyond ___ years of age
4 years. Anterior open bite, posterior crossbite, increased overjet, high vaulted palate, possible class II relation, distorted incisor eruption
BQ: What is the most common ankylosed tooth?
mandibular first molars
Average ANB?
2-4 degrees
What is the incidence of congenitally missing permanent teeth?
4%, no gender differences (2% are maxillary laterals)
Average SNA?
80-82 degrees
FMA of 31 degrees: Brachyfacial or dolichofacial
Dolichofacial
Primary spacing affects crowding outcomes predictors into the mixed dentition. What % chance of crowding with no spacing?
50% with incisor crowding
Define functional posterior cross bite
shift of the mandible on closure. This masks bilateral maxillary constriction and makes it appear to be unilateral crossbite, even though the crossbite is bilateral and a product of bilateral maxillary constriction
What is the treatment for a functional crossbite?
Removable hawley with finger springs, fixed palatal rigid archwire with finger springs, labial archwire with edgewise brackets
Non-nutritive sucking habit: Which is more critical, duration or force of strength of force?
NNS: Duration of force rather than magnitude
What class occlusion is being described: functional cross bite with lingually displaced upper incisors complicated by anterior shift of the mandible that exaggerates cross bite discrepancy
pseudo class 3
BQ: Ankylosed teeth: list them from most common to least
lower first molars -> upper first molars -> lower second molars -> upper second molars
What % of mesiodens are single?
80%
20% are more than one
Distal step primary molar class relationship usually results in which permanent molar relationship?
Class 2 or end on end class 2 molar relationship
What occurs when there is an early mesial shift in a FTP class occlusion?
first permanent molars erupt in end on relationship and class 1 relationship is achieved by EARLY mesial shift
Moyer’s probability chart has what level of probability?
75%; the advantage of moyer’s mixed dentition analysis is that it does NOT require a radiograph
What is recommended ortho wise after extracting primary canines to prevent lingual collapse of lower incisors, increased overjet, deepened bite, and loss of arch length?
Placement of LLHA
2/3 of ectopically erupting 1st permanent molars self-correct. After what age do they rarely self correct?
7
Primary spacing affects crowding outcome predictors into the mixed dentition. What is the % chance of incisor crowding with spacing of 3-6mm?
No transitional crowding
T/F: Small maxillary laterals, lateral with a pronounced distal inclination, non-mobile primary canines, eruptive building of canines are all signs of maxillary canine eruptive displacement
True - remove primary canines whenthe permanent canines #6,11 have about 2/3 root structure
What is the goal of maxillary expansion? (2 things)
1) Correct transverse discrepancy
2) Eliminate functional shift
What class relationship can occur from excessive mesial step with crossbite?
Class III
When is the best time to extract #C and H?
Remove primary canines when the permanent canines have about 2/3 root structure. Note: if canine overlaps beyond the lateral incisors long axis, successful reposition is approximately 60%
What is the Leeway space of Nance?
the combined mesiodistal width of primary canines, first and second molars
maxilla: 1.5 mm
mandible: 1.5 mm both sides
Where is space loss most significant?
maxillary arch after loss of A or J
T/F: FMA less than 21 - vertical deficiency?
true
Bilateral posterior crossbite is associated with what type of skeletal vertical growth pattern?
Dolichofacial
RPE, Haas, sutural expansion. W-arch/quad helix = slow and low force
What is the term for a shift of the mandible on closure. This masks bilateral maxillary constriction and makes it appear to be unilateral crossbite, even though the crossbite is bilateral and a product of bilateral maxillary constriction
Functional crossbite - greater than 90% of primary dentition crossbites express a functional shift in their occlusion pattern
Space loss is most severe in which arch after loss of second molars?
maxillary arch
What class relationship are mesial step canines?
Class I relationship
What age is the permanent dentition generally complete?
Age 12 - Maxilla: 6, 1, 2, 4, 5, 3, 7
What are the risks of removing lower primary canines?
lingual collapse of incisors -> increased overjet, loss of arch length, bite deepening
Define class 2 div 2
maxillary central incisors are retroclined and a deep overbite exists, lateral proclined
In what class of occlusion is lateralization of canines emphasized?
Class II occlusion
Describe a skeletal class 3 relationship
1) Prognathic mandible
2) Retrognathic maxilla
3) Typically involves all anterior teeth in crossbite
4) Proclined upper, retroclined lowers
What is the average mandibular incisor crowding?
1.0mm to 1.6mm
After 8-9, there are no future arch dimensional changes to compensate for crowding/ malalignment in the lower anterior segment
T/F: 60-70% of malalignments are from early loss of primary tooth
True
What are the primate spaces located?
Maxilla: Lateral to canine
Mandible: Canine to first primary molar
simian or anthropoid spaces or meyers or ebners spaces
Erupting premolars will move through 1 mm of bone in ___ months
4-5 months
If crowding is excessive (3-4mm), develop a plan to develop the arch (not serial extraction)
disk canines 1-2 mm each
What are the simian or anthropoid spaces also known as?
Primate spaces = meyers or ebners space
What would the treatment for managing space be if more than 4 mm of space needs to be gained?
Extract primary canines
Disc 1-2 mm of mesial buccal of primary canines if less than 3-4 mm of space needed
Which tooth is the best predictor of sagittal relationship into the permanent dentition?
Canine
What is the mandibular leeway space?
1.7 mm per quadrant (3.4 mm total)
Eruption: 6-1-2-3-4-5-7
There are case reports of second premolar tooth germs developing as late as__ years of age
10
When do you consider cessation therapy for non-nutritive sucking habits?
prior to eruption of permanent anterior teeth, around age 5,6 if the NNS habit persists
What is the formula for the maxilla using Tanaka Johnson?
(1/2)x(combined mesiodistal width of all 4 mandibular incisors+11)
T/F: Primary teeth erupt on average from 8 months (lower incisors) to 30 months (upper second molars) with a S.D. of 3 months. Sequence of both arches is the same: A B D C E
True
What % of primary dentition exhibits generalized spacing?
2/3 (66%) Baume type one
What % of mesiodens are palatal?
90%
75% require surgical intervention as they do not erupt on their own
Primary spacing affects crowding outcomes predictors into the mixed dentition. What % chance of crowding with spacing less than 3 mm?
20% with incisor crowding
