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Orthodontics Part IOrthodontics Part I
Paul K. Chu, DDS
22 NOV 2010
REVIEW FROM LAST LECTUREREVIEW FROM LAST LECTURE
So a 0.05% NaF daily rinse (ACT) has how much mg fluoride per mL?
Step 1Step 1-- Convert to F ion.Convert to F ion.*** % NaF x 0.45 = %F ion****** % NaF x 0.45 = %F ion***0.05% x 0.45 = 0.0220 % F0.05% x 0.45 = 0.0220 % F-- ionion
Step 2Step 2-- Convert % FConvert % F-- ion to ppmion to ppm***%F ion x 10***%F ion x 1044= ppm F***= ppm F***0.0220% x 100.0220% x 104 4 = ~220 ppm F ion= ~220 ppm F ion
REVIEW FROM LAST LECTUREREVIEW FROM LAST LECTURE
Step 3 Convert ppm F ion to mg/mL
*** ppm = mg/L ***
220 ppm F ion = 220mg/Lpp g
We want denominator to be mL, so with stoichiometry …
220 mg X 1 L = 0.22 mg/mL
L 1000mL
In the ABPD review book it’s 0.022 !!!
FROM THE ABPD REVIEW FROM THE ABPD REVIEW BOOK BOOK
EE--MAIL FROM DR. ADAIR MAIL FROM DR. ADAIR 10/01/200510/01/2005
OK, I think I see where the error is - it's in the table at the top of page 18, where the concentration is given as "0.022" under the
l h d d "M F i L " Tcolumn headed "Mg F ion per mL, cc, or g." Two other places in that section, it's given correctly. I'll make sure the typo is corrected in the nextedition. Thanks.
Steve
July 01, 2003July 01, 2003yy
2
My first day as a Pedo My first day as a Pedo ResidentResident
CONFUSING???CONFUSING???
As much as you don’t want to As much as you don’t want to learn Ortho…you learn Ortho…you MUSTMUST be be
competent is its basics.competent is its basics.
7/1999 3/2002
4
INTRODUCTIONINTRODUCTION
Sequence of Calcification of Primary Teeth
Central Incisor (#a) 14 weeks in utero
First Molar (#d) 15 weeks in uteroFirst Molar (#d) 15 weeks in utero
Lateral Incisor (#b) 16 weeks in utero
Cuspid (#c) 17 weeks in utero
Second Molar (#e) 18 weeks in utero
A BCD
E
AB
C
D
E
12345
678
Positioning of Primary Teeth
5
Facial TypesFacial Types
Straight Protrusive Retrusive
Typical Child Profile
Rule of ThirdsRule of Thirds Class I OcclusionClass I Occlusion
MB CUSP of Upper 6 occludes with B Groove of lower 6
Class 1Class 1-- MalocclusionMalocclusion
l Cl Molars - Class I
Anterior crowding
Class 2 Class 2 --MalocclusionMalocclusion
Class II
Retrognathic profile Retrognathic profile
In this case, it is a FULL cusp Class II
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Class 2 MalocclusionClass 2 Malocclusion-- Division 1Division 1
Class II Molars
BUCALLY FLARED BUCALLY FLARED Incisors
Class 2 MalocclusionClass 2 Malocclusion-- Division 2Division 2
Class 2 Division 2 Incisors RETROCLINED
Class 3 Class 3
Prognathic mandible
In this case, we have a FULL CUSP Class 3
Classification of Occlusion of the Primary Second Molar
Flush terminal plane
Mesial step
Look at the distal aspect of the 2nd molar
es a step
Distal step
Flush Terminal Plane Flush Terminal Plane
-Historically seen as ‘normal’
-observed 30%
Distal Mesial
Mesial Step
MS of 1 mm observed 40%
MS >1mm observed 20%
Distal Mesial
7
Distal Step
Distal M i l
DS of 1 mm observed 10%
Distal Mesial
PERCENTAGES:PERCENTAGES:Relation of primary 2Relation of primary 2ndnd molar relation to molar relation to
permanent molar occlusion*permanent molar occlusion*
56% Class I; 44% Class II
(1mm) 76% CI; 23% CII; 1% CIII
(≥2mm) 68% CI; 13%CII; 19%CIII
Class II- 99.999999%
*Bishara, et. Al- “Facial & Dental Changes in Adolescents & Their Clinical Implications (2000)
PERCENTAGES:PERCENTAGES:Relation of Spacing/Crowding in the Primary Relation of Spacing/Crowding in the Primary
Dentition to Permanent DentitionDentition to Permanent Dentition
1o Spacing ≥ 6mm= no crowding
1o Spacing 3-6mm =20% crowding
1o Spacing < 3mm 50% crowding
1o No Spacing = 66% crowding
1o Crowding = 100%
Primary CrowdingPrimary Crowding
Almost 100% chance Almost 100% chance of permanent crowding
No SpacingNo Spacing
66% chance of 66% chance of crowding in the permanent denition
Spacing 3-6 mm=
FairFair-- to Good Spacingto Good Spacing
Spacing 3 6 mm 20% chance of crowding
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Good Spacing!!Good Spacing!!
1o Spacing ≥ 6mm= no crowding
Primate SpacePrimate Space
-Primate spaces occur in about 50% of children.
-Maxilla: lateral incisor and the upper canine.
-Mandible: between the lower canine and the deciduous first molar.
Leeway SpaceLeeway Space
Measures mesial distal width of primary CDE and compares to analogous succeedaneous 3-4-5
Sum of (c-d-e) > (3-4-5) This allows more space for 3-4- This allows more space for 3 4
5 This "leeway space" averages
1.7 mm. in the mandibular buccal segment; 0.9 in the maxillary buccal segment
Early Mesial ShiftEarly Mesial Shift
occurs when the 1st permanent molars erupt (5 5 6 5 years)erupt (5.5-6.5 years) and cause a mesial shift into the primate space.
Late Mesial ShiftLate Mesial Shift
FTPMolar moves into
this space... Class I
Ugly Duckling StageUgly Duckling Stage
9
OTHER NORMSOTHER NORMS
Overbite is a vertical measurement of the amount of overlap of the incisors. Overjet is the millimeter horizontal measurement from the labial of the maxillary central incisor to the labial of the mandibular central incisor.
Overjet = 0-4mm
Overbite= 10-40%
6 e d c 2 1
6 d 2 1
1 2 c d e 6
1 2 d 6
Definition of a Mixed Dentition
6 e d c 2 1 1 2 c d e 6
Incisor Liability Incisor Liability
•Permanent incisors are larger than primary incisors
•This difference in size is termed "incisor liability"liability
•**In the maxilla, the difference is 7.6 mm. In the mandible, the difference is 6.0 mm. **
•How does the body create enough room for the larger, permanent incisors?
Ways to Overcome Incisor Ways to Overcome Incisor Liability Liability
Interdental spacing of primary incisors Intercanine arch width growth Labial positioning of the permanent incisors Favorable size ratio between the primary and
permanent incisors
Good interdental spacing of primary incisors allows for better alignment of the larger permanent incisors.
Primary Spacing Primary Spacing Intercanine arch width growth Intercanine arch width growth
– width growth creates more room for the permanent incisors
– mandibular intercanine th tlgrowth occurs mostly
during permanent incisor eruption
– maxillary intercanine growth occurs during incisor eruption, and continues
– unpredictable
10
Labial positioning of the Labial positioning of the permanent incisors permanent incisors
– permanent incisors erupt to a more labial position
– permanent incisors are angled more labially
– this all creates more arch length
Favorable size ratio between the Favorable size ratio between the primary and permanent incisors primary and permanent incisors
– size ratio between the primary and permanent p y pincisors may be favorable or unfavorable
– favorable: large primary, small permanent
– unfavorable: small primary, large permanent
What is Arch Length?What is Arch Length?
Arch length is the distance in millimeters from the mesial of the 1st permanent molar around the arch over the contact points to thearch over the contact points to the mesial of the 1st permanent molar on the opposite side.
What is the BEST predictor of What is the BEST predictor of saggital relationship insaggital relationship insaggital relationship in saggital relationship in permanent dentition?permanent dentition?
Primary Canine RelationshipPrimary Canine Relationship
Look at long axis of the maxillary cuspid
N t id (Cl I) Neutro cuspid (Class I)
Disto cuspid (Class II)
Mesio cuspid (Class III)
Neutro Cuspid
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Disto Cuspid
- Class II
Mesio Cuspid
Neutro/Slight MS= Class I
Excessive MS= Class III
AnalysisAnalysis
Use of techniques to predict spacing
During the mixed dentition
Moyer’s Analysis Step BY StepMoyer’s Analysis Step BY Step
STEP 1:– a) Measure mesial - distal widths of mnd
incisors– b) Measure space of anterior segment available– Subtract B from A– Negative number indicates less space is
available
Moyer’s Analysis Step BY StepMoyer’s Analysis Step BY Step
STEP 1:
Negative number– Negative number indicates less space is available
Moyer’s Analysis Step BY StepMoyer’s Analysis Step BY Step
STEP 2:– a) Measure space available for 3-4-5 on each side ) p
of the arch (distal of lateral incisor to mesial of 1st
molar)– b) Calculate from prediction table the size of 3-4-5
(using the measured sized of the mandiublar incisors that we used in Step 1)
– Subtract B from A
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Moyer’s Analysis Step BY StepMoyer’s Analysis Step BY Step
STEP 2:
– Calculate from di ti t bl th iprediction table the size
of 3-4-5
– This is the Moyers Prediction table
– Uses Md Incisors as measuring ‘guides’
Moyer’s Analysis Step BY StepMoyer’s Analysis Step BY Step
STEP 2:
– In our case, we had 23.0 mm
We meas re space– We measure space available as 20.1 & 19.5 per side (for our example)
– what is our predicted Mandibular 3-4-5 space needed?
Moyer’s Analysis Step BY StepMoyer’s Analysis Step BY Step
STEP 2:– In our case, we had
23.0 mmW– We measure space available as 20.1 & 19.5 per side
– what is our predicted Mandibular 3-4-5 space needed?
Moyer’s Analysis Step BY StepMoyer’s Analysis Step BY Step
STEP 2:
Subtract tooth size from space available on left and right
At this point, you should have three numbers:– number for incisor crowding or excess space
– number for right buccal segment crowding or excess
Moyer’s Analysis Step BY StepMoyer’s Analysis Step BY Step
number for right buccal segment crowding or excess space
– number for left buccal segment crowding or excess space
Add the three numbers: negative = crowding, positive = space
Add ‘em up!!Add ‘em up!!
(-2.1) + (-3.2) + (-2.7) = (-8.0)
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If we measured mandibular incisors, and their added mesio-distal width is 21.9
h t i th
Anyone…..Anyone…..
mm, what is the expected width (using Moyers Analysis) of the maxillary 3 – 4 –5’s?
Tanaka Johnson AnalysisTanaka Johnson Analysis
MUCH EASIER!!!!
Mx: add 11 5mm to Mn incisal Mx: add 11.5mm to Mn incisal measurement= Mx buccal segment requirements
Mn: add 10.5 mm to Mn incisal= Mn buccal segment requirements
IDEAL PRIMARY OCCLSUIONIDEAL PRIMARY OCCLSUION
FTP/ Mesial step molars + Canines FTP/ Mesial step molars + Canines Generalized primate spacing 2 mm OJ 2mm OB Ovoid Arches
ReferencesReferences
Board Review Handbook: 2009 ABPD
Bishara et Al. “Facial and dental changes in adolescents and their clinical implications.” Angle Orthod. 2000 Dec;70(6):471-83. ( )
www.uic.edu
http://cudental.creighton.edu