CAST ANALYSIS

Syeda Tooba Zaidi

1.Introduction.2.Classification.3.Mixed dentition analysis1.Space analysis.2.Mixed dentition period.4.Methods of mixed dentition analysis.a)Moyer’s mixed dentition analysis.b)Tanaka Johnston mixed dentition analysis.c) Hixon & Oldfather prediction method.d) Huckaba mixed dentition analysis.5. Method of Permanent dentition Analysis.a) Bolton's analysis

INTRODUCTION• Model analysis is the study

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

CLASSIFICATION• Model analysis can be classified in the following

ways1.Based on whether the analysis is on the

permanent dentition or on the mixed dentition. • PERMANENT DENTITION ANALYSES.• Ashley howe’s.• Carey’s / Arch perimeter.• Pont’s.• Linder Hearth’s.• Korkhau’s.• Bolton’s.

Mixed dentition analysis

• Moyer’s.• Tanaka

Johnston.• Hixon and Old

father.• Staley kerber.• Huckaba’s.• Ballard and

Willie

2.Based on the arch in which the analysis is carried out ,they can be classified as. MAXILLARY ARCH•Pont’s•Linder hearth’s•Korkhau’sArch perimeter. MANDIBULAR ARCH•Carey’s•Hixon and Old father•Peck and peck•Staley Kerber

3.Based on principles of space analysis;a) NON –RADIOGRAPHIC SPACE ANALYSES• Moyer’s•Tanaka Johnston•Ballard and Wylieb) RADIOGRAPHIC ANALYSES• Nance’s• Huckaba’sc) COMBINATION OF RADIOGRAPHS AND PREDICTION CHARTS• Hixon and Old father• Staley kerber

PRINCIPLES OF SPACE ANALYSIS• Imp to quantify the amount of

crowding within the dental arch.• Space is required to correct, crowding,

leveling of occlusal curve, arch contraction, correction of upper incisor angulation, correction of UI inclination (torque).

• To plan whether the crowding can be treated with extraction or non-extraction.

• Requires comparison between space available and space required.

• To exactly determine how much space would be required to align and level all the permanent teeth.

MIXED DENTITION ANALYSISANALYSIS IS BASED ON FOLLOWING PRINCIPLES (FIELDS AND PROFFIT)a) 1st permanent molar and permanent incisors are erupted.b) The succedaneous permanent teeth are forming.c) Size relationship between unerupted permanent teeth and primary teeth.d) There is size difference in primary canines and molars and the succedaneous teeth.e) M-D width of primary canines and molars is greater than perm’ successors (leeway space).

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MIXED DENTITION ANALYSISSpace available in upper and lower arches:•This is accomplished by measuring arch perimeter from the mesial of one first molar to the other over the contact points of posterior teeth and incisal edge of anterior.2 basic ways to measure manually.1. By dividing dental arch into segments.2. By contouring a piece of wire to the line of occlusion & then straightening it out for measurement.•The 1st method is preferred for manual calculation b/c of its greater reliability.

MIXED DENTITION ANALYSISSpace required in Upper &Lower arches:•To calculate the amount of space required for alignment of teeth, this is done by measuring the mesio-distal width of each erupted tooth.•Measure with veneer caliper or with two point divider, and write down the values, and then summing the width of individual teeth.•Do this for both upper & lower teeth.Note for unilateral Impacted or Unerupted Teeth•If tooth is unerupted or impacted in one quadrant then add the same mesiodistal width of the opposite tooth in its place.

Different method of Mixed Dentition Analysis

Teeth To Estimating the Size of Unerupted Permanent

teeth Three basic approaches to doing this.1. Measurement of teeth on radiograph.2. Estimation from proportionality tables.3. Combination of radiographic and prediction table method.

1. RADIOGRAPHIC METHODHUKABA’S MIXED DENTITION ANALYSIS

RADIOGRAPHIC METHOD 1964• This requires an undistorted radiographic

image, which is more easily achieved with individual PA radiographs than with Panoramic radiographs. E

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2.ESTIMATION FROM PROPORTIONALITY TABLES

1.MOYER’S MIXED DENTITION ANALYSIS 19731. Measure the widths of each of four permanent mandibular incisors.2. Total the M-D widths of mandibular incisors.3. Using prediction chart for space available in mandibular arch, locate the value closest to the sum of four mandibular incisors.4. The predicted tooth size of 3,4 and 5 is compared with the arch length available for them so as to determine the discrepancy.5. If the predicted value is greater than the available arch length, crowding of teeth can be expected.

2. Tanaka and Johnston prediction values.1974•The mesiodistal width of the lower incisors is measured and this number is used to predict the size of both the lower and upper unerupted canines and premolars.

Advantages• 1. Technique involves simple, easily repeated procedure with minimum material requirement. 2. Prediction chart and radiograph is not required.Limitations Error in predicted size if patients are not from north western.

Why take lower incisors?Because upper lateral incisor has number of variations.Peg shape, missing, extra large, too small.

3.COMBINATION OF RADIOGRAPHIC AND PREDICTION TABLE METHOD

HIXON AND OLD FATHER (Staley & Kerber revision) FOR THE MANDIBULAR ARCH 1956

1. From the casts, on one side, measure the m-d widths of the permanent mandibular central and lateral incisor.2.From the periapical radiographs, measure the m-d width of unerupted first and second premolars3.Total the m-d widths of four(4) teeth.4. Compare the measured value to estimated tooth size from the Hixon- Oldfather chart.

Repeat steps 1 to 3 for the other side of the arch.ADV. Very accurate technique.LIMITATIONS. Only use for lower arch.

• Hixon and Oldfather: most accurate.• Tanaka and johnston : most practical.• Radiographic method: for population other method. for

population other than Caucasians.• Which of these method is best for an individual patient work

depends on circumstances.• All prediction table work surprisingly.

IRWIN R, HEROLD J, RICHERDSON A (1995)They did a review of Methods that have been proposed for mixed

dentition analysis , Studies comparing the different methods have shown that the method of Hixon & Oldfather (1958), as refined by Staley & Kerber (1980), is the most accurate.

* Mixed dentition analysis forms an integral aspect of orthodontic diagnosis to determine whether the treatment plan is going to involve serial extraction, space maintenance, space gaining or simply periodic observation of the patient

PERMANENT DENTITION ANALYSIS

BOLTON’S ANALYSIS..It is also called ‘TOOTH SIZE ANALYSIS’..It is carried out by measuring the mesio-distal width of each permanent tooth..A standard table is then used to compare the summed width of the maxillary and mandibular teeth and the total width if upper and lower teeth (excluding second and third molars)..A tooth size discrepency of less than 1.5mm is rarely significant, but larger discrepencies create treatment problems and must be included in the orthodontic problem list.

BOLTON’S ANALYSIS CHART

• REFRENCES:• William R. Proffit 4th edition.• Laura Mitchell 3rd edition.• Moyers. • S.M bhalajhi 4TH edition.