UG Model Analysis Pont's and Linder Harth index

Pont’s Index

Pont’s index helps in:

1.    Determining whether the dental arch is narrow or normal

3.    Determining how much expansion is possible at premolar and molar regions

The greatest width of incisors is measured with calipers recorded on a line, & their sum is recorded in millimeters

              This is termed as “sum of incisors” (SI)

Calculated premolar value (CPV)

The required arch width in the premolar region is calculated by formula:-

                 SI X 100

                     80

Calculated molar value (CMV)

The required arch width in the molar region is calculated by formula:-

                 SI X 100

                     64

Measured premolar value (MPV)

The distance between the upper right first premolar & upper left first premolar (that is the distal end of the occlusal grove) is recorded (Fig 17) & called as “measured premolar value” (MPV)

FIG 17 : Measurement of premolar width (MPV)

Measured Molar value (MMV)

The distance between the upper right first molar & upper left first molar (that is the mesial pit on the occlusal surface in maxillary arch ) is recorded (Fig 18) & is termed as “measured molar value” (MMV)

FIG 18 : Measurement of molar width (MMV)

Inference                    

Difference between the measured & calculated values indicate expansion or contraction of arches. The amount of contraction determines the needs for expansion

  1) If measured value is less, expansion is required

  2) If measured value is more, inference of expanded arch is drown and further expansion cannot be done.

Linder Harth Index

It is very similar to Pont’s analysis however he made a variation in the formula to determine the calculated premolar value as per the population sample.

·      Calculated premolar value:-

                    SI X 100

        85                      

·      Calculated molar value:-

        SI X 100

             65