Space analysis is a crucial diagnostic tool in orthodontics for assessing the maxillary and mandibular dental arches in three dimensions. It involves various methods, such as Moyer’s and Tanaka-Johnston analyses, to measure available space for unerupted teeth, guiding treatment decisions. Accurate space analysis helps determine orthodontic treatment plans and whether tooth extractions are necessary.

1. Space Analysis
Dr. Arun Sharma
Professor and Head
Dept. of Pedodontics and Preventive Dentistry
Rama Dental College-Hospital & Research Centre,
Kanpur

2. INTRODUCTION:
•Space analysis which is also known as a MODEL ANALYSIS is one
of the essential diagnostic aids.
•The study models provide a three dimensional view of the maxillary and
mandibular dental arches in all the three planes of space (sagittal, vertical, and
transverse planes).
•Study models helps to visualize the patient’s occlusion from all aspects and also
helps in making the necessary measurements of the teeth and the dental arches
and the basal bone.
•Space analysis is a valuable tool in orthodontic diagnosis and treatment
planning.

3. STUDY MODELS

4. SPACE ANALYSIS
Space analysis is defined as the study of maxillary and mandibular arches in all the
three planes of space (sagittal, vertical and transverse) and is valuable tool in
orthodontic diagnosis and treatment planning.
USES:
•It helps in making necessary measurements of teeth, dental arches, basal bone to
carry out space analysis.
•It offers a three dimensional view of the dental arches and patient’s occlusion.

5. IMPORTANCE OF SPACE ANALYSIS:-
•Space analysis is the foundation of all orthodontic treatment plans and is critical in
deciding whether functional and cosmetic orthodontic goals can be achieved.
•An organized, comprehensive, integrated space analysis will help dentists to choose
between varieties of treatment approaches and to determine if permanent teeth
must be extracted.

6. Mixed dentition:-
•Hixon and Old father’s method.
•Moyer’s mixed dentition analysis.
•Nance analysis.
•Tanaka-Johnston analysis.
TYPES OF SPACE ANALYSIS:-

7. MIXED DENTITION ANALYSIS:-
The assessment of spacing or crowding of teeth is frequently associated with
measurements in mixed dentition stage because accurate and specific
prediction of future dental development can be made at this stage.
Commonly used mixed dentition analysis are:-
•Huckaba’s analysis.
•Hixon and Old father’s method.
•Moyers mixed dentition analysis.
•Hays - Nance analysis.
•Total space analysis.
•Tanaka- Johnston analysis.

8. HUCKABA’S ANALYSIS:-
He used both study casts and radiographs for determining the width of
unerupted tooth.
Principle:
•To compensate for enlargement of radiographic images measure an object that
can be seen both in radiograph and on cast such as primary molar tooth.
•Accuracy of this method of determining the width of unerupted tooth is fair
to good, depending upon the quality of the radiographs and their position in the
arch.
•This technique can be used both in maxillary and mandibular arches in all ethnic
groups.

9. •A simple proportional relationship can be then established, as follows:
Y1 = X1 * Y2/X2
X1= Actual width of primary molar.
X2= Apparent width of primary molar.
Y1= Actual width of unerupted premolar.
Y2= Apparent width of unerupted premolar.

10. MOYER’S SPACE ANALYSIS:-
•It is widely used, because it has minimal systematic errors.
•It can be used with reliability as it does not require sophisticated instruments
and is less time consuming.
•The purpose of a mixed dentition analysis is to evaluate the amount of space
available in the arch for the erupting permanent canines and premolars.

11. PROCEDURE:-
To determine the space available for teeth in mandibular arch.
•With the help of Boley’s gauge, it measures the mesiodistal width of each
mandibular incisor, separately.
•To determine the amount of space required for alignment of incisors. Set
gauge to value of sum of central and lateral incisors.
•Place one point of the Boley gauge at the midline and let other end lie along the
dental arch on one side of central and lateral incisors whose widths were
measured, mark this point on the cast. It represents the point at which the
distal surface of lateral incisor will be when it has been aligned properly.
• Repeat this for opposite side.

12. •To determine the amount of space available for permanent canine and premolars
after incisors alignment. Measure the distance from point marked on the cast to
the mesial surface of first permanent molar.
•Using Moyer’s probability chart find out the sum total mesiodistal width of
upper and lower cuspids and bicuspids for the given sum width of lower central
and lateral incisors at 75% probability.
•Compare the space available and space required in all four quadrants to
determine arch length discrepancy.

13. Advantages:
•It has minimal error and the range of possible error is precisely known.
•It can be done with equal reliability either by a beginner or by an expert.
•It is not time consuming.
•It requires no special equipment.
•It can be done in the mouth as well on the cast.
•It may be used on both the arches.
Inference:
•If the predicted value is greater than available arch length crowding of teeth
can be expected.

14. Moyer’s mixed dentition analysis

16. TANAKA-JOHNSTON ANALYSIS:
To determine the mesiodistal width of unerupted permanent canine and
premolars in the mixed dentition period.
Procedure:
•From permanent first molar on one side, mark the distances on casts in
segments to the permanent first molar on the opposite side. Measure these
segments over the contact points.
•Add the measurements to determine the total arch circumference.
•Measure the mesiodistal widths of the mandibular central and lateral incisors.
•Subtract this total from the arch circumference measurement.

17. •Divide the sum of the widths of the mandibular incisors by 2 and add 10.5mm
for the mandibular arch.
•This total gives the estimated size of the mandibular canine and the two
premolars on one quadrant.
•Double the total for the canines and the premolars in the mandibular arch.
•Subtract this dimension from the remaining space available in the arch to give a
positive or negative total arch space.
•For the maxillary arch, repeat the process.
However, instead of adding 10.5mm to the widths of the mandibular incisors, add
11.0mm to the sum.

19. Inference:
•If the result is positive, there is more space available in the arch than is
needed for the unerupted teeth.
•If the result is negative, the unerupted teeth require more space than is
available to erupt into ideal alignment.

20. Advantages:
•Improving on the Moyer’s analysis, it is relatively accurate for children of
European ancestry.
•The technique involves simple, easily repeated procedures and minimal material
needs.
•It does not use prediction charts.
Limitations:
•There may be error in the predicted size of the unerupted teeth if patients are
not of Northwestern European descent.

21. Conclusion:
To conclude, Space analysis hence is a one of the most essential diagnostic
aides which helps to visualize the patient’s occlusion from all aspects and
helps in treatment planning.