Moyer's analysis is a commonly used mixed dentition analysis technique. It uses the mesiodistal widths of the mandibular incisors to predict the combined widths of the canines and premolars using probability tables. Several studies have evaluated the accuracy of Moyer's analysis for different populations and found it often overestimates tooth sizes. New regression equations have been developed to more accurately predict tooth widths for specific ethnic groups. Alternative mixed dentition analysis methods use radiographs or formulas to estimate unerupted tooth sizes with varying degrees of accuracy depending on the population.

1. MODEL ANALYSIS

2. INTRODUCTION
OModel analysis is a three dimensional
assessment of the maxillary and
mandibular dental arches and occlusal
relationships for orthodontic diagnosis
and treatment planning

3. OIt is a diagnostic aid, one can analyze
the arch form, arch symmetry,
alignment of the teeth, palate shape,
tooth size, tooth shape, rotations of
teeth and other information.

4. OUTLINE
Diagnostic
data
Radiographs
IOPA
Bite-wing
Lateral jaw
projection
Occlusal plane
Panaromic radiograph
Lateral cephalogram
Intra-oral
examinations
Dental casts
Photographs

5. IOPA
Bite-wing
Lateral jaw projection
Panaromic radiograph
Lateral cephalogram

7. Model analysis
Permanent
dentition
analysis
Mixed
dentition
analysis

8. Mixed
dentition
analysis
Moyer's
analysis
Huckaba’s
analysis
Hixon and
Oldfather
analysis
Nance and
Carey’s
analysis
Tanaka and
Johnston
analysis

9. Permanent
analysis
Pont’s analysis
Linder Harth analysis
Korkhaus analysis
Peck and peck analysis
Carey’s arch perimeter
analysis
Ashley Howe’s analysis
Bolton analysis
Sanin- Savara analysis

10. MIXED DENTITION
ANALYSIS

11. OThe purpose of a mixed dentition analysis
is to evaluate the amount of space
available in the arch for succeeding
permanent teeth and necessary occlusal
adjustments
OEarly treatment is becoming increasingly
popular in orthodontics, it is imperative
that mixed dentition analysis is accurately
done before any orthodontic treatment is
offered (Cunat,1982 , Proffitand Fields,
2000)

12. OSpace analysis involves comparison
between amount of space available for
alignment of teeth and amount of space
required to place them in correct position
OProminent among conditions requiring
early attention are those in which there is
disparity between amount of dental arch
space and amount of tooth material which
should be accommodated(Huckaba, 1964)

13. OAny deficit of arch space is predicted in advance
and indicated procedures instituted early
(Huckaba,1964 , Proffit and Fields,2000)
OAn accurate mixed dentition space analysis is
one of the important criteria in determining
whether treatment plan may involve serial
extraction, guidance of eruption , space
maintenance, space regaining or just periodic
observation of patients ( Bishara and Jakobsen,
1998)

14. FACTORS CONSIDERED FOR
AN ANALYSIS
O To complete an analysis of mixed dentition, 3 factors
must be noted
1. Sizes of all permanent teeth anterior to first
permanent molar
2. Arch perimeter
3. Expected changes in arch perimeter which may occur
with growth and development

15. AVERAGE MESIODISTAL
WIDTH OF TEETH
Primary Mixed Permanent
Maxilla 68.2 75.8 74.0
Mandible 61.8 67.8 64.4
Anterior to first permanent molar

16. MAIN ASPECTS OF AN ANALYSIS
OMixed dentition analysis helps to estimate
amount of spacing or crowding which would
exist for the patient if all primary teeth were
replaced by their successors the very day the
analysis is done , not 2 or 3 years later
ODoes not predict the amount of natural decrease
in perimeter which may occur during transitional
period without loss of teeth

17. MOYER’S ANALYSIS
OThe basis of Moyer’s analysis is that
there is high co-relation among groups of
teeth. Given by Robert Moyers in 1971
OMeasuring one group of teeth, that is
mandibular incisors , it is possible to
make a prediction on size of other groups
of teeth with a fair degree of accuracy

18. REASON FOR CHOOSING
MANIBULAR INCISORS
OMandibular incisors erupt early in mixed
dentition and offer earliest opportunity of
measurement
OThey are also less variable and more reliable
than maxillary incisors and are directly in midst
of most space management problems
OMaxillary incisors are not used since they show
too much variability in size and their correlation
with other groups of teeth are of lower
predictive value

19. PROCEDURE IN MANDIBULAR
ARCH
1. Measure with tooth measuring gauge or a
pointed Boley gauge, the greatest mesiodistal
width of each of four mandibular incisors.
2. Determine the amount of space needed for
alignment of incisors
OSet the boley gauge to a value equal to the sum
of the widths of left central incisor and left
lateral incisor

20. O Place one point of the gauge at the midline of the
alveolar crest between central incisors and let other
part lie along the line of dental arch on left side
O Mark on the tooth or the cast the precise point
where the distal surface of lateral incisor will be
when it has been aligned
O Repeat this process for the right side of the arch

22. IN CASE OF MIDLINE DEVIATION, MIDLINE IS
ADJUSTED IN CAST

23. ONOTE:
If cephalometric evaluation shows
mandibular incisors to be too far labially, the
boley gauge tip is placed at the midline, but
moved lingually a sufficient amount to
stipulate the expected uprighting of incisors
as dictated by cephalometric evaluation

24. 3. Compute the amount of space available after
incisor alignment
OTo do this, measure the distance from the
point marked in line of the arch to mesial
surface of first permanent molar
OThis distance is the space available for the
cuspid and two bicuspids and for any
necessary molar adjustment after the incisors
have been aligned
ORecord the data for both sides
OPredict the size of the combined width of the
mandibular Cuspids and Bicuspids.

26. Long method
O An experienced clinician can use 50% Prediction
since it is more precise estimate.
O For inexperienced clinicians, they should use the
75% Prediction for combined widths of Canines
and two Premolars.

27. Probability table for predicting the sizes of
unerupted Cuspids and bicuspids

28. Short Method-
O Less precise method
O Add the width of the mandibular incisors and
divide by two.
O To the value obtained add
O 10.5mm Mandibular Cuspids and
Bicuspids
O 11.0mm Maxillary Cuspids and Bicuspids

29. OWhether using the long or short method,
record the estimated values for the combined
cuspids and bicuspids widths in the mixed
dentition analysis form for both sides and
each arch.
 Compute the amount of space left in the
arch for molar adjustment by subtracting the
estimated Cuspid and Bicuspids size from the
measured space available in the arch after
alignment of the incisors.
 Record these values for each side.

30. PROCEDURES IN MAXILLARY ARCH
O Similar to that of mandibular arch with 2 exceptions
1. A different probability chart is used for predicting
upper cuspid and bicuspid sum
2. Allowance must be made for overjet correction when
measuring the space to be occupied by the aligned
incisors
O NOTE: Remember that width of lower incisors are used
to predict upper cuspid and bicuspid widths

31. Probability Table for prediction

32. ADVANTAGES
O Has minimal systematic error and range of such errors is
precisely known
O Doesn’t require any specific equipment or radiographic
projections
O Can be used for both arches
O Doesn’t require sophisticated clinical judgement and saves
time
O Can be done in mouth and in casts
O Can be done with equal reliability by the beginner and
expert

33. DISADVANTAGES
O It was developed on a Caucasian population, the
applicability of this method to populations of other ethnic
groups has been studied and doubted
O Requires a special chart for prediction of width of canines
and premolars

34. PROBLEMS FACED IN
MOYER’S ANALYSIS
OProblem arises when considering the space
left for molar adjustment
OIf differential skeletal growth occurs,
alterations in molar relationship will result
and mixed dentition analysis predictions must
be altered accordingly

35. OInability to reflect the position of incisors with
respect to skeletal profile
OAs a result, clinician may assume there is
sufficient space for all teeth until the arch is made
level during treatment
OMixed dentition analysis is a 2 dimensional
visualization of a complex 3 dimensional problem

36. O Umapathy et al., (2015)
O Conducted a study to test the reliability of
Moyer’s method and to produce new regression
equation for Bangalore population for
predicting the mesiodistal diameters of the
unerupted permanent canines and premolars.

37. O Data was collected from study models of 400
randomly selected Bangalore subjects aged 13
to 16 years with fully erupted, intact dentitions
and no significant malocclusion.
O The mesiodistal widths of the incisors, canines
and premolars of both arches were measured.
O This data was then utilized to predict the
mesiodistal widths of canines and premolars
and further compared with Moyer’s table.

38. O It was found that 50% is more applicable to
boys and 75% to girls.
O The canine premolar segment in both arches is
statistically larger in men than in women
(p<0.05).
O New regression equation was formulated, the
accuracy of which needs to be evaluated
further in a larger sample.

39. O Kamalshikha et al., (2016)
O Conducted a study to evaluated the applicability of
Moyer’s mixed dentition space analysis in the
Marwari community of Rajasthan, India.
O The mesiodistal dimension of permanent mandibular
incisors, maxillary and mandibular canine, and
premolars of both sides were measured and averaged
in 200 adolescents (100 males and 100 females) of
the Marwari population in Rajasthan using digital
Vernier caliper.

40. O The data were then compared with Moyer’s predicted
values.
O Moyer’s prediction chart was not comparable with
the study population group. The coefficient of
correlation and coefficient of determination in study
was 0.57 and 0.25, respectively.
O Mesiodistal width of measured teeth was lesser in
females compared to males for both canine and
premolars

41. O There was significant statistical difference between
values of the present study and Moyer’s prediction
values.
O Hence, new regression equation and prediction table
can be used to predict mesiodistal dimensions of
canine and premolars in Marwari children of
Rajasthan.

42. Huckaba’s analysis
O Recommended by Huckaba.G.W in 1964
OHe uses both study casts and radiographs for
determining width of unerupted tooth
OWith any type of radiograph, it is necessary to
compensate for enlargement of radiographic
image.
OThis can be done by measuring an object that can
be seen both in radiograph and on cast

43. O Actual width of primary molar X1
Apparent width of primary molar X2
=
Actual width of unerupted premolar Y1
Apparent width of unerupted premolarY2
O Y1 = X1× Y2
X2
O Accuracy of this method of determining depends on
the quality of the radiographs and their position in
the arch
O This technique can be used in maxillary and
mandibular arches for all ethnic groups

45. Hixon and Oldfather’s
Analysis (1958)
O Armamentarium
O Procedure
O Inference

46. Armamentarium
O A lower mixed dentition cast.
O Periapical x-ray film.
O Tooth measuring gauge.

47. O Mesio distal width of the mandibular central and lateral
incisor is obtained from the cast
O Determine width of premolars from intra-oral periapical
radiographs
O Sum up the width of incisors and unerupted premolars of
that side
O The estimated sum total width of cuspids and bicuspids of
that side can be obtained from the given chart
O Every measured sum width of incisor and bicuspids has a
corresponding sum width of the cuspids and bicuspids in
the chart

49. Inference
O The predicted tooth size is compared with the arch length
available, so as to determine the discrepancy.
O If predicted value > available arch length = Crowding.

50. Nance and Carey’s analysis
O This is similar to arch perimeter analysis of permanent
dentition
O Measure the mesio - distal width of the erupted permanent
teeth
O Measure width of each unerupted teeth cuspids and
bicuspids (3,4,5) from intra oral periapical radiographs

51. O Total width of all teeth in each quadrant will indicate
space required to accommodate the permanent teeth
O Using brass wire, measure the perimeter
O Compare the space required and space available to
arrive at the arch length discrepancy

52. Tanaka and Johnston Method
(1974)
O Dr Marvin M Tanaka & Dr Lysle E
Johnston
OTo evaluate the space requirements for
unerupted permanent teeth, usually the
canines and premolars

53. Armamentarium
O A lower cast.
O Tooth measuring gauge.

54. Procedure
O Prediction of the size of the permament canine and
premolars.
O Advantage:-
O Requires neither radiographs nor reference tables.

55. O Measure greatest mesiodistal width four permament
mandibular incisors.
O Predict the size of the combined width of the
mandibular and maxillary cuspid and bicuspid by the
use of Tanaka and Johnston's formula.

56. O Predicted width of maxillary canine and premolar
=Sum of mandibular incisors + 11mm
2
O Predicted width of mandibular canine and premolars
=Sum of mandibular incisors + 10.5mm
2

57. Inference
O The predicted tooth size is compared with the arch
length available, so as to determine the discrepancy.
O If predicted value > available arch length = Crowding.

58. Drawback
O When the mesiodistal width of the canine and premolars
is
O Small - overestimates the actual size of the canine and
premolars.
O large - underestimates the actual size of the canine
and premolars.
O Range - 22.0 to 24.0 mm.

59. Simple linear regression 2 equations were derived
for prediction of unerupted premolar and canines in
the maxilla and mandible.
Maxillary Y = 10.41+0.51(X)
Mandibular Y = 10.41+0.54(X)
Where Y = premolar and canine width in a quadrant
X = measured mandibular incisor width

60. O NAMITHA RAMESH et al., (2014)
O Conducted a study to evaluate the reliability of
Tanaka and Johnston and Moyer’s (75th percentile)
mixed dentition prediction methods in Kodava
population sample, to formulate regression equations
for predicting the mesiodistal widths of unerupted
canines and premolars and to construct probability
tables for the Kodava population.

61. O Dental models of 30 male and 30 female Kodava
subjects (age range is 16 - 23 yr) were used.
O Teeth measured included mandibular permanent
incisors, maxillary and mandibular permanent
canines, first and second premolars.
O Digital caliper calibrated to 0.01mm was used to
record mesiodistal dimensions.

62. O The actual teeth measurements were then statistically
compared with the predicted values derived from the
Tanaka and Johnston’s equations and Moyers
probability tables at the 75th percentile.
O Tanaka and Johnston prediction equations
overestimated the mesiodistal widths of
permanent canines and premolars in both the
arches.

63. O Moyers 75th percentile also overestimated the
actual measurements except for the maxillary arch
in female subjects.
O The percentage of overestimation was more for
Tanaka – Johnston prediction method than that of
Moyers (75th percentile).

64. O The commonly used Tanaka and Johnston and
Moyers (75%) prediction methods were not as
accurate when applied to our sample of Kodava
population since it tends to overestimate the actual
measurements.
O New regression equations for the Kodava
population were formulated for predicting the
mesiodistal widths of unerupted canines and
premolar segments for males and females separately.

65. O Vikasini et al., (2015)
O Conducted a study to determine the most reliable
mixed dentition analysis method for Nalgonda
population.
O Study was conducted on 60 boys and 60 girls of
Nalgonda population, in the age group of 13–16
years.
O The mesiodistal and buccolingual dimensions of the
permanent incisors, canines, premolars, and 1st
permanent molars were measured on the study
models of all the subjects.

66. O Seven different mixed dentition analyses were
performed which include Bachmann’s, Gross and
Hassund’s, Trankmann et al., Camilo et al., Legovic
et al., Tanaka–Johnston and Moyer’s methods and
were later compared.
O The Pearson’s Correlation coefficients were
calculated between the sums of the mesiodistal
diameters (MDDs) of permanent canine, and
premolars as measured on the study models and the
predicted MDDs of the same using each of these
seven methods

67. O The correlation coefficient r was highest for Moyer’s
mixed dentition analysis with a value of 0.957 and
0.979 in the mandibular and maxillary arch
respectively for boys and 0.935 and 0.946 in the
mandibular and maxillary arch respectively for girls.
O Conclusion: Moyer’s mixed dentition analysis was
found to be the most reliable method for both boys
and girls of Nalgonda population of all the 7
methods compared.

68. O Kamalshikha Baheti et al.,(2016)
O Evaluation of Moyer’s mixed dentition space
analysis in Indian children.
O The mesiodistal dimension of permanent
mandibular incisors, maxillary and mandibular
canine, and premolars of both sides were
measured and averaged in 200 adolescents
(100 males and 100 females) of the Marwari
population in Rajasthan using digital Vernier
caliper.

69. O Moyer’s prediction chart was not comparable
with the study population group. The coefficient
of correlation and coefficient of determination
in our study was 0.57 and 0.25, respectively.
O Mesiodistal width of measured teeth was lesser
in females compared to males for both canine
and premolars (P = 0.471 and P = 0.0001,
respectively).

70. Conclusion: There was significant statistical
difference between values of the present
study and Moyer’s prediction values.
Hence, new regression equation and prediction table
can be used to predict mesiodistal dimensions of
canine and premolars in Marwari children of
Rajasthan.

71. REFRENCES
O Robert E. Moyers Chicago: Year Book Medical Publishers, 1988. 4th ed
• William R Profit .Contemporary orthodontics. 4th ed; Mosby;2012.
• Gurkeerat singh. Textbook of orthodontics : 2nd ed. Jaypee brothers
medical publishers (P) Ltd; 2007.
• Thomas M Graber's. Textbook of Orthodontics: orthodontic current
principles and techniques. 4th ed; Elsevier India;2010.
O Bishara, Samir E. Textbook Of Orthodontics. 1st ed. Philadelphia:
Saunders, 2006. Print.

72. O Umapathy T, Sarvesh S, Hassan C, Nagamangala
L. Validity of Moyers Mixed Dentition Analysis and
a New Proposed Regression Equation as a
Predictor of Width of Unerupted Canine and
Premolars in Children. J Clin Diagn Res.
2015;9(8): ZC01-ZC06.
O Butt S, Chaudhary S, Javed M, Wahid A. Mixed
dentition space analysis: a review. POD.
2012;32(3):502-7.

73. O Namitha R, MORA R, Biswas P. Mixed
Dentition Space Analysis in Kodava
Population: A Comparison of Two Methods. J
Clin Diagn Res. 2014;8(9): ZC01-ZC06.
O Baheti K, Babaji P, Ali MJ, Surana A, Mishra S,
Srivastava M. Evaluation of Moyer's mixed
dentition space analysis in Indian children. J
Int Soc Prevent Communit Dent 2016;6:453-8.