Department of Orthodontics Model Analysis Bolton's Analysis Techinque Advantages and Disadvantages

4. Model Analysis is the study of dental casts, which
helps to study the occlusion and dentition from all
three dimensions and analyze the degree and
severity of malocclusion and to derive the
diagnosis and plan for treatment.

5. It is the study of maxillary and mandibular dental
arches in all three planes of space(Saggital,
Vertical, Transverse planes.

6. They are three dimensional records of the patients
dentition.
Occlusion can be visualised from lingual aspect.
They provide a permanent record of the
intermaxillary relationship.
Helps to motivate the patients as they can visualise
the treatment progress.
They are needed for comparison purposes at the
end of the treatment and act as a reference for post
treatment changes.

7. They serve as a reminder for the parent and the
patient of the condition present at the start of the
treatment.
In case the patient has to be transferred to another
clinician study model are an important record.

8. Most of the studies were done on a specific
population and the ratio obtained need not be
applicable to other population groups.
It does not take into account the sexual
dimorphism in the teeth.
Does not take skeletal malrelation into
consideration.

9. It does not take into account the relationship of
the teeth to surrounding bone or the difficulties
in increasing the mandibular dimensions.

10. WAYNE A.BOLTON pointed out that the
extraction of one tooth or several teeth should
be done according to the ratio of tooth material
between the maxillary and mandibular arch.
To get and ideal interdigitation,overjet,overbite
and alignment of teeth.

11. To attain an optimum interarch relationship.
Boltons analysis helps to determine the
disproportion between the size of maxillary
and mandibular teeth.

12. The sum of mesiodistal diameter of the 12 maxillary
teeth and the sum of the mesiodistal diameter of the
12 mandibular teeth are determined.

13. In the same manner the sum of the 6 maxillary
anterior teeth and the sum of the 6 mandibular
teeth is determined.

14. OVERALL RATIO
Sum of mesiodistal width of mandibular 12 teeth x 100
_____________________________________________
Sum of mesiodistal width of maxillary 12 teeth
MEAN= 91.3 %

15. ANTERIOR RATIO
Sum of mesiodistal width of mandibular 6 teeth x 100
_______________________________________
Sum of mesiodistal width of maxillary 6 teeth
MEAN= 77.2 %

16. IF The ratio is more than the mean value than the
mandibular tooth material is excess.
If the ratio is less than the mean value then the
maxillary tooth material is excess.
Bolton preferred to do proximal stripping on the
upper arch if the upper anterior tooth material is
in excess and extraction of lower incisor ,if
necessary to reduce tooth material in lower arch.

17. Study was done on a specific population and
ratio obtained need not be applicable to other
population group.
The analysis doesn’t take into account the
sexual dimorphism in the maxillary canine
width.