Bolton analysis and mixed dentition analysis

Orthodontics-Space analysis

1. Dr Bushra Naeem BOLTON ANALYSIS AND MIXED DENTITION ANALYSIS

2. BOLTON ANALYSIS

3. Bolton analysis According to B olton there exist a ratio between the mesiodistal width of maxillary and mandibular teeth Bolton analysis helps in determining tooth size discrepancy

4. Determining overall ratio Mesiodistal width of all the teeth which are mesial to the permanent 2 nd molar is measured Overall ratio= Sum of mandibular 12 x 100 Sum of maxillary 12

5. If the ratio is less than 91.3% it indicates maxillary tooth material excess Amount of excess can be calculated by Sum of maxillary 12- sum of mandibular 12 × 100 91.3

6. If the ratio is greater than 91.3% it indicates mandibular tooth material excess Amount of excess can be calculated by sum of mandibular 12- sum of maxillary 12 × 91.3 100

7. Anterior Ratio Mesidistal width of all anterior 6 maxillary and mandibular anterior teeth is measured Anterior ratio= sum of mandibular 6 × 100 sum of maxillary 6

8. If the ratio is less than 77.2% it indicates maxillary anterior excess material . Amount of excess material can be calculated by Sum of maxillary 6- sum of mandibular 6 × 100 77.2

9. If the ratio is greater than 77.2% it indicates mandibular anterior excess material Amount of excess can be calculated by sum of mandibular 6 – sum of maxillary 6 × 77.2 100

10. MIXED DENTITION ANALYSIS The purpose of mixed dentition analysis is to evaluate the amount of space available in the arch for eruption permanent canine and premolars This can be achieved by predicting the mesiodistal width of unerupted premolars and canine

11. Methods Radiographic method Moyers prediction table Tanaka and johnston equation Staley kerber method

12. Radiographic method Also known as Hukaba’s analysis With any type of radiograph, it is necessary to compensate for the radiographic enlargement, this can be achieved by measuring the object which is available on both radiograph and the cast.

13. A proportional relationship is set up true width of primary molar = apparent width of primary molar true width of unerupted premolar apparent width of unerupted premolar

14. This technique can be used on maxillary and mandibular arches for all ethnic groups Its accuracy depends on the quality of the radiograph

15. Moyers prediction table Moyers predicted the combined mesiodistal width of canine and premolars based on the sum of lower 4 incisors Based on this calculation, the expected width of canine and premolars is predicted by referring the Moyers prediction values.

16. Moyers prediction values Total mandibular incisors width 19.5 20.0 20.5 21.0 21.5 22.0 22.5 23.0 Predicted values of canine and premolar maxilla 20.6 20.9 21.2 21.3 21.8 22.0 22.3 22.6 mandible 20.1 20.4 20.7 21.0 21.3 21.6 21.9 22.2

17. Accuracy of this method is fairly good for European white children on whom data was tabulated No radiograph required

18. Tanaka and johnston Tanaka and johnston developed another way of using the width of lower 4 incisors to predict the size of canine and premolars. Mesiodistal width of lower 4 incisors is obtained and an equation is applied.

19. Estimated width of lower canine and premolar of one quadrant= ½ of the mesiodistal width of 4 incisors+10.5mm Estimated width of upper canine and premolar of one quadrant= ½ of the mesiodistal width of 4 incisors+11mm

20. Staley kerber graph Combination of radiographic and prediction table method Mesiodistal width of central and lateral lower incisors is measured from the cast. Determine the width of premolars from the periapical radiograph. Sum up the mesiodistal width of central and lateral incisors and premolars of that particular side Staley and kerber graph allows canine width to be read directly from the sum of incisors and premolars width

21. This method can only be used on mandibular arch Quite accurate for European ancestry

22. Which method to be used?

23. THANK YOU