Truly Invisible Braces: The Story of Serial Disking
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Transcript of Truly Invisible Braces: The Story of Serial Disking
Truly Invisible Braces: Truly Invisible Braces: The Story of Serial DiskingThe Story of Serial Disking
Dr Jabbarifar Dr Jabbarifar Associate ProfessorAssociate Professor
IsfahanUniversity School of Dentistry 2009IsfahanUniversity School of Dentistry 2009
objective
part 1 Discuss the transition of the primery
dentition to the permanent dentition.part 2
Review a simplified Mixed Dention Analysis procedure .
part 3 Discuss indications and procedures for
Serial disking .
Part 1 - Transition From PrimaryPart 1 - Transition From Primary to Permanent Teethto Permanent Teeth
Transition of molar relationships Transition of molar relationships Transition of Incisors Transition of Incisors Transition of Buccal Segment Transition of Buccal Segment
Leeway Space Leeway Space Late Mesial Shift Late Mesial Shift
Distal Mesial
Flush Terminal PlaneFlush Terminal Plane
Distal Mesial
Mesial Mesial StepStep
Distal Mesial
Disto Disto StepStep
Distal Mesial
Mesio Mesio StepStep
Incisor LiabilityIncisor Liability
Permanent incisors are Permanent incisors are larger than primary larger than primary incisorsincisors
This difference in size is This difference in size is termed "incisor liability“termed "incisor liability“
How does the body How does the body create enough room for create enough room for the larger, permanent the larger, permanent incisors?incisors?
Overcoming Incisor LiabilityOvercoming Incisor Liability
Interdental spacing of primary incisors Interdental spacing of primary incisors Intercanine arch width growth Intercanine arch width growth Labial positioning of the permanent incisors Labial positioning of the permanent incisors Favorable size ratio between the primary Favorable size ratio between the primary
and permanent incisorsand permanent incisors
Arch Length Prediction fromArch Length Prediction from Alignment of Primary TeethAlignment of Primary Teeth
Primary Alignment Permanent Outcome
Crowding Almost certain extraction
No spacing Possible extraction
Fair spacing Mild to Moderatecrowding
Good spacing No or mild crowding
Excess spacing No crowding/excess
Good SpacingGood Spacing
No Primary SpacingNo Primary Spacing
Fair SpacingFair Spacing
Leeway SpaceLeeway Space
Sum of (c-d-e) > (3-4-5) Sum of (c-d-e) > (3-4-5) This allows more space for 3-4-5 This allows more space for 3-4-5 This "leeway space" averages 1.7 mm. in This "leeway space" averages 1.7 mm. in
the mandibular buccal segment; 0.9 in the the mandibular buccal segment; 0.9 in the maxillary buccal segmentmaxillary buccal segment
““E” SpaceE” Space
Late Mesial ShiftLate Mesial Shift
Refers to mandibular permanent molar Refers to mandibular permanent molar moving mesially moving mesially
Good news - if permanent molars are ETE, Good news - if permanent molars are ETE, late mesial shift allows mandibular molar to late mesial shift allows mandibular molar to move into a Class I occlusion move into a Class I occlusion
Bad news - the above reduces arch lengthBad news - the above reduces arch length
FTP
Class IMolar moves into this space...
Late Mesial Shift (cont.)Late Mesial Shift (cont.)
Late Mesial Shift (cont.)Late Mesial Shift (cont.)
Part 2 Mixed Dentition AnalysisPart 2 Mixed Dentition Analysis
Purpose: predict amount of crowding after Purpose: predict amount of crowding after permanent teeth come in permanent teeth come in
Timing: mixed dentition Timing: mixed dentition Materials: Boley gauge Materials: Boley gauge Where: At the chairWhere: At the chair
4 Step Simplified MDA4 Step Simplified MDA
Basic Steps Basic Steps – Mentally align incisors Mentally align incisors
» In other words…. “how far over onto the primary In other words…. “how far over onto the primary cuspid will it take to make the incisors straight?” cuspid will it take to make the incisors straight?”
– Measure space left over for C, B1, B2 Measure space left over for C, B1, B2 – Predict size of C, B1, B2 Predict size of C, B1, B2 – Compare size vs. space for C, B1, B2 to Compare size vs. space for C, B1, B2 to
determine amount of crowdingdetermine amount of crowding
Step 1 MDA MethodologyStep 1 MDA Methodology
Measure mesial-distal diameter of the Measure mesial-distal diameter of the mandibular incisors, sum and divide by twomandibular incisors, sum and divide by two
Tooth Number Measurement
23 6.1
24 5.6
25 5.5
26 6.2
Sum 23.4
½ Sum 11.7
Step 1 ExampleStep 1 Example
Step 2 MDA MethodologyStep 2 MDA Methodology
Select a midline point Select a midline point Expand the Boley gauge to the amount Expand the Boley gauge to the amount
determined in Step 1 determined in Step 1 Mark the point on each primary cuspid from Mark the point on each primary cuspid from
the midline point the midline point This represents the space required for well This represents the space required for well
aligned incisors aligned incisors
11.7 mm 11.7 mm
Step 3 MDA MethodologyStep 3 MDA Methodology
Measure from the point on each cuspid Measure from the point on each cuspid (derived in Step 2) to the mesial of the first (derived in Step 2) to the mesial of the first permanent molarpermanent molar
This represents the space available for the This represents the space available for the permanent cuspid and bicuspids (C, B1, B2)permanent cuspid and bicuspids (C, B1, B2)
22.4 mm 22.7 mm
Step Left Side Right Side
½ Sum of lowerincisors 11.7 11.7
Space Available(C, B1, B2)
22.7 22.4
Tooth Size = 11.7 +10.5 (C, B1, B2)
Crowding/ quadrant
Sum of Crowding
Step 3 ExampleStep 3 Example
Step 4 MDA MethodologyStep 4 MDA Methodology
To the number derived in Step 1, add 10.5 To the number derived in Step 1, add 10.5 mm for the mandibular teethmm for the mandibular teeth
This represents the size of the permanent This represents the size of the permanent cuspid and bicuspids in each quadrantcuspid and bicuspids in each quadrant
Subtract the number determined in Step 4 Subtract the number determined in Step 4 (the predicted size of C, B1, B2) from the (the predicted size of C, B1, B2) from the number determined in Step 3 (the amount of number determined in Step 3 (the amount of space for C, B1, B2) for both sides of the archspace for C, B1, B2) for both sides of the arch
MDA MethodologyMDA Methodology
If the space available is less than the If the space available is less than the amount of tooth mass, a negative number amount of tooth mass, a negative number will resultwill result
This number is the predicted amount of This number is the predicted amount of crowdingcrowding
Step 4 ExampleStep 4 Example
Step Left Side Right Side
½ Sum of lowerincisors 11.7 11.7
Space Available(C, B1, B2)
22.7 22.4
Tooth Size = 11.7 +10.5 (C, B1, B2) 22.2 22.2
Crowding/ quadrant + 0.5 + 0.2
Sum of Crowding + 0.7
Allowance for Late Mesial ShiftAllowance for Late Mesial Shift
If permanent molars are end to end, If permanent molars are end to end, mandibular molar should move mesially to mandibular molar should move mesially to obtain Class I interdigitation.obtain Class I interdigitation.
This will decrease the arch length available This will decrease the arch length available for 3-4-5.for 3-4-5.
Figure 1.7 mm. per side with ETE Figure 1.7 mm. per side with ETE relationship.relationship.
MDA Procedure Maxillary ArchMDA Procedure Maxillary Arch
Mentally align the maxillary incisors as was done Mentally align the maxillary incisors as was done in the mandibular arch in the mandibular arch
Measure the space left over for the maxillary C, Measure the space left over for the maxillary C, B1, B2 B1, B2
Add 11.0 mm. to 1/2 the sum of the Add 11.0 mm. to 1/2 the sum of the MANDIBULAR INCISORS to predict the size of MANDIBULAR INCISORS to predict the size of the maxillary C, B1, B2the maxillary C, B1, B2
Subtract the predicted size from the space Subtract the predicted size from the space availableavailable
Part 3 Serial DiskingPart 3 Serial Disking
Result without treatment Result without treatment Description of Ideal Patient Description of Ideal Patient Description of Technique Description of Technique Steps in Serial DiskingSteps in Serial Disking
What Happens With No What Happens With No Intervention?Intervention?
Cuspid Cuspid Labial EruptionLabial EruptionNo anterior alignmentNo anterior alignment
1st Premolar Eruption1st Premolar EruptionDistal cuspid movement?Distal cuspid movement?
2nd Premolar Eruption2nd Premolar EruptionLate mesial shift of 1st molar Late mesial shift of 1st molar
Spaces close from posterior!!!
2nd Premolar Eruption2nd Premolar EruptionLate mesial shift of 1st molar Late mesial shift of 1st molar
Result Without DiskingResult Without Disking
Same anterior crowding Same anterior crowding Blocked out cuspids Blocked out cuspids Less arch length to work withLess arch length to work with
Ideal Patient for Serial DiskingIdeal Patient for Serial Disking
Class I molars and Class I molars and cuspids (Not FTP) cuspids (Not FTP)
Normal overbite Normal overbite and overjet and overjet
3 mm or less of 3 mm or less of anterior crowdinganterior crowding
Serial Disking TechniqueSerial Disking Technique
699, 169 carbide bur or tapered diamond 699, 169 carbide bur or tapered diamond Anesthetic considerations Anesthetic considerations
local local electronic electronic none none
Prepare mesial surface as stainless steel Prepare mesial surface as stainless steel crown prep crown prep
No ledges!…. Feather edge marginNo ledges!…. Feather edge margin
Serial Disking Steps:Serial Disking Steps:Mandibular ArchMandibular Arch
Lateral incisor eruption - disk mesial of Lateral incisor eruption - disk mesial of primary cuspids primary cuspids
Permanent cuspid eruption - disk mesial of Permanent cuspid eruption - disk mesial of either 1st or 2nd primary molareither 1st or 2nd primary molar
Mild Anterior CrowdingMild Anterior CrowdingDisk Primary CuspidsDisk Primary Cuspids
Mild Anterior CrowdingMild Anterior CrowdingDisk Primary CuspidsDisk Primary Cuspids
Cuspid Cuspid EruptionEruptionExtract 1st Primary Molar?Extract 1st Primary Molar?
Cuspid Cuspid EruptionEruptionExtract 1st Primary Molar?Extract 1st Primary Molar?
1st Premolar Eruption1st Premolar EruptionDisk 2nd Primary MolarDisk 2nd Primary Molar
1st Premolar Eruption1st Premolar EruptionDisk 2nd Primary MolarDisk 2nd Primary Molar
Disk 2nd Primary MolarDisk 2nd Primary Molar
Class I Molars
Class I Molars PreferredClass I Molars PreferredNo late mesial shift requiredNo late mesial shift required
2nd Premolar Eruption2nd Premolar Eruption
End to End MolarsEnd to End MolarsNo late mesial shiftNo late mesial shift
NEXT SLIDENEXT SLIDE
If You Can’t Disk Enough…If You Can’t Disk Enough…and <5 mm. Crowding...and <5 mm. Crowding...
Extract mandibular primary cuspids Extract mandibular primary cuspids Support with bilateral holding arch Support with bilateral holding arch Mandibular incisors will generally align Mandibular incisors will generally align Just because 5 mm. of crowding is Just because 5 mm. of crowding is
predicted does not mean it is an extraction predicted does not mean it is an extraction case! Why?case! Why?
Other Factors to ConsiderOther Factors to Consider
Tooth size prediction is at approximately 75 Tooth size prediction is at approximately 75 percentile percentile therefore….. Tendency is to overestimate therefore….. Tendency is to overestimate
crowding crowding
MDA does not take into account: MDA does not take into account: angulation of incisors angulation of incisors arch form arch form Curve of SpeeCurve of Spee
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Creighton University http://www.creighton.edu http://www.creighton.edu Creighton School of Dentistry http://cudental.creighton.edu http://cudental.creighton.edu ASDC Web site http://cudental.creighton.edu/asdc http://cudental.creighton.edu/asdc