MODEL ANALYSIS

Done by:Ala Alaqqad U00020080

BOLTON’S ANALYSIS

Factors affect occlusion

Anterior Bolton analysis Full archBolton analysis

• The Bolton analysis has been designed following observation that tooth size was important to ideal occlusion

• Bolton calculated that a constant proportion between the upper and the lower dentition was present when the occlusion was perfect.

• He determined that the sum of the mesio-distal dimension of the lower teeth must be equal to 91.3% of the sum of the mesio-distal dimension of the upper teeth.

• More importantly, he also discovered that a satisfactory Cl I canine occlusion was only possible if a specific proportion was present between the upper and lower anterior teeth.

• The sum of the size of the mesio-distal dimension of the lower anterior teeth in this instance must be 77.2% of the sum of the size of the mesio-distal dimension of the upper anterior teeth.

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INTRODUCTION

CLASSIFICATION

PERMANENT DENTITION MODEL ANALYSIS

MIXED DENTITION MODEL ANALYSIS

Arch perimeter analysis Moyer’s Mixed dentition analysis

Nance Carey’s analysis Tanaka and johnston analysis

Ashley Howe’s analysis Nance mixed dentition analysis

Pont’s analysis Huckaba’s mixed dentition analysis (Radiographic method)

Linder Harth analysis

Korkhaus analysis

Bolton’s analysis

Peck and Peck index

REQUIREMENTS TO DO BOLTON’S MODEL ANALYSIS

• Well prepared study models

• Vernier calipers

• Divider Or

• The difference between the space required and space available gives the arch discrepancy or excess.

• If the tooth material is more than the arch length, the space available for alignment is not sufficient results in crowding.

• If the tooth material is less than the space then there can be spacing.

BOLTON’S ANALYSIS

• It helps to determine the disproportion between the size of mandibular and maxillary teeth.

• In well aligned upper and lower arches with normal overjet and overbite, there exists a definite proportionality of tooth size between the two arches.

• If the proportionality is met, the maxillary dentition fits well with the mandibular teeth.

• The presence of disproportionately sized teeth in either arch can make it difficult to obtain an occlusion with good alignment, ideal overjet, ideal overbite, and a class I molar relationship.

• The primary purpose of Bolton’s analysis is to determine mathematical ratios between total lengths of dental arches ( total tooth material) as well as between segments of tooth material (anterior tooth material).

• Tooth Material = Greatest mesiodistal diameter

Cast analysis

TOTAL TOOTH RATIO / OVER ALL RATIO

• The ratio of the percentage relationship of sum width of mandibular tooth material as measured from first molar to first molar width to that of corresponding maxillary dentition.

STEPS

• SUM OF MANDIBULAR 12: the mesiodistal width of all the teeth mesial to the mandibular second permanent molars is measured and summed up.

• SUM OF MAXILLARY 12: the mesiodistal width of all the teeth mesial to the maxillary second permanent molars is measured and summed up.

• If the overall ratio is less than 91.3%, it indicates maxillary tooth material excess.

• The amount of maxillary tooth material excess is determined by using the formula

=

• If the overall ratio is more than 91.3%, it indicates mandibular tooth material excess.

• The amount of mandibular tooth material excess is determined by using the formula

=

ANTERIOR TOOTH RATIO

• The ratio of the percentage relationship of mandibular anterior width to the maxillary anterior width.

• SUM OF MANDIBULAR 6: the mesio distal width of all the anterior six teeth are measured and summed up

• SUM OF MAXILLARY 6: the mesio distal width of all the anterior six teeth are measured and summed up

• The anterior ratio is determined using the following formula:

• If the anterior ratio is less than 77.2%, it indicates maxillary anterior tooth material excess.

• The amount of maxillary tooth material is determined using the formula:

• If the anterior ratio is more than 77.2%, it indicates mandibular anterior tooth material excess.

• The amount of mandibular tooth material is determined using the formula:

Anterior Bolton analysis Full archBolton analysis

CONCLUSION

• In order to obtain the proper interdigitation and arch coordination when the molars are in a Cl I molar relationship, the dimension of the lower teeth has to be proportional to the dimension of the upper teeth.

• To present a normal overbite and overjet, the lower teeth must form a dental arch that is smaller than the upper arch.

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