Model analysis - Bolton's Analysis

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

1. GOOD MORNING

2. MODEL ANALYSIS

3. DEFINITION 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.

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

5. advantages 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.

6. 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.

7. DISADVANTAGES 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.

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

9. BOLTON ANALYSIS 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.

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

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

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

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

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

15. INFERENCES 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.

16. DRAWBACKS 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.