BORDERLINE CASES
BORDERLINE CASES
CONTENTS
Introduction
History of extraction philosophy
Decision making aids
Effects of extraction and non extraction treatments
Non extraction treatments
Class III borderline
Conclusion
INTRODUCTION
Extraction of permanent
teeth is required to reach a
stable and functional
occlusion
When patient has good
facial esthetics that could be
disturbed by extractions
HISTORY OF EXTRACTIONS
DECISION-MAKING AIDS
1948, Downs
Acceptable ranges of ten
diagnostic variables
Earliest cephalometric
analyses
“Single readings are not so
important”
Vorhies and Adams
“difficulty of developing a
suitable mental picture.”
Organized data describing
acceptable ranges
Wigglegram
Efficient method to analyze
cephalometric measures
• Rody and Araujo
• Relationships of
dental, skeletal, and
facial cephalometric
measurements
• Extraction Decision-
Making Wigglegram
(EDMW)
Extraction decision-making wigglegram. J Clin Orthod 2002;36:510-519
DENTAL VARIABLES
Dental discrepancy
Curve of spee
Boltons discrepancy
Peck and peck analysis
Irregularity index
DENTAL DISCREPANCY
Carey 2.5mm to 5mm TASLD as borderline case
McNamara arbitrary borderlines of 3 to 6 mm
Luppanapornlarp and Johnston
1mm of crowding in either arch definitive non extraction
Definitive extraction therapy in maxillary and mandibular
arches was 5.8 and 7.3 mm, respectively
Proffit and Fields
Less than 4 mm ALD:
Extractions rare (only in incisor protrusion or posterior vertical
discrepancy)
ALD 5mm to 9 mm:
Extraction/non-extraction decision depends on characteristics
of patient
ALD 10mm or more:
Extractions always required
CURVE OF SPEE
1 mm of arch circumference for each millimeter of
curve of Spee
Recent studies suggest ratio1:3
• Woods- variable depending on type of mechanics used.
• Roth - 3 to 6 mm of curve of Spee mild
• Baldridge > 6 mm is severe
BOLTONS DISCREPANCY
4 mm limit to anterior reduction.
Extraction necessary discrepancy greater than this
Neff
Maxillary to mandibular cuspid-to-cuspid ratio -1.22
Anterior Bolton ratio of .772
PECK AND PECK ANALYSIS
An index between 88 -95 indicates good anatomical shape.
Index > 95 M-D width greater than buccolingual width.
Borderline patients with narrow lower incisors need extraction
IRREGULARITY INDEX-
LITTLE
Mandibular incisor alignment
Adding linear distances
between five adjacent
anatomical contact points
Perfectly aligned incisors-
zero.
Score > 6.5 millimeters
likelihood for extraction.
CEPHALOMETRIC VARIABLES
HORIZONTAL PLANES
FMA
SN-MP
PFH/AFH
FMIA
IMPA
1-A-POG LINE
UPPER AND LOWER CENTRAL INCISOR TO N-A AND
N-B LINE
HORIZONTAL PLANES
Highly divergent planes
favors extraction.
Parallel horizontal planes not
favor extraction.
INCISOR POSITION
Orthodontists may disagree which incisor is of greater
diagnostic value
Margolis IMPA 90+/-3 degrees in normal, balanced faces
Charles Tweed - “upright” and “vertical” lower incisors
85 and 95 degrees, according to ethnicity
Due to functional and esthetic impairment, an IMPA greater
than 96° is an indication for extraction
Frankfort mandibular
incisor angle (FMIA).
Norm 60-70°.
A value < 60°
indicates proclination
Value > 70° incisors
retroclined
McNamara
1 to 3 mms anterior to
(A-Pog)
Regardless of age
STEINER
Extraction more likely as
incisor positions and angles
exceed values Horizontal
planes
NB
NA
FACIAL VARIABLES
Profile of the patient
Lower lip to E –line
Lower lip to B-Line
Naso labial angle
Upper lip morphology
Midline Deviation
Lower lip to E –line
Age and sex
Standard deviation - 3mm
Lower lip to B-Line
2.5 ± 1.5mm anterior
EFFECT OF EXTRACTION ON LIPS
Ramos et al, for each 1 mm retraction upper lip retracts 0.75
mm
Talass et al 1/0.64
Massahud and Totti 1/0.5
Regarding lower lip, for 1 mm retraction, retracts 0.6 mm
Nasolabial angle
Burstone 73.8 degrees +/- 8
Recent studies range of 90
to 115 degrees.
Drobocky and Smith
Extraction of four bicuspids
increase nasolabial angle
5.2 degrees
Upper lip morphology
Thickness measured in two
different areas
Borderline patients with strained
lips
Incisors retracted without altering
soft tissue profile
Lip needs to reach normal form
before retraction
Lips would immediately follow
tooth movement in normal lips.
Effect of extraction on Soft tissue profile
L.A.Bravo, extractions of upper 1st premolars
3.4 mm backward movement of upper lip related to‘E’ line
3.7° increase in NLA
0.9 mm decrease in superior sulcus depth (Holdaway)
Extractions contraindicated
Nasolabial angle > 110°
Ls to Sn –Pog’ line < 3mm
Li to Sn-Pog’ line < 2mm
Ss to H line < 3mm
Li to H line < 0mm
Six Keys to Nonextraction Treatment
DAN COUNIHAN 2005 JCO
First Key: Leeway Space
7mm in lower arch and 5mm in upper arch
Lip bumper, lingual arch, or palatal bar before second
deciduous molars exfoliate
Second Key: Mesial Molar Rotations
Rotated upper molar occupy 12mm width, compared to
10mm for a properly oriented first molar
Third Key: Passive Uprighting
Constrictive forces of lips and cheeks removed
Studies shown 4mm increase in arch width
Achieved with lip bumpers or Fränkel appliances
Fourth Key: Active Uprighting
Fifth Key: Distal Movement
Sixth Key: Skeletal Modification
Borderline Class III Malocclusion
KERR ET.AL. ( BJO 1992)
Establish cephalometric yardsticks
Surgery performed
ANB angle < -4°
M/M ratio of 0.84
Inclination lower incisors 83°
Holdaway angle of 3.5°
STELLZIG-EISENHAUER
Formula developed
On basis on the four variables:
Wits appraisal
Length of anterior cranial base
M/M ratio
Lower gonial angle
Ind Score= -1.805+0.209Wits+0.044SN+5.689M/M ratio
0.056Go
Cr Score = - .023
< Orthodontic- orthognathic therapy
> Orthodontic therapy
CONCLUSION
Experience plays significant role
Any decision regarding need for extraction not only dependent
on presence or absence of space
Other issues
Proper malocclusion correction
Improvement of facial aesthetics
Result stability