Dr Arif Ismail

Department of Orthodontics

NANCE ANALYSIS &

MILLS AND HAMILTON ANALYSIS

NANCE ANALYSIS

• Introduction

• Procedure

• Inference

MILLS & HAMILTON ANALYSIS• Introduction

• Procedure

• Inference

CONTENTS

N A N C E A N A L Y S I S

HAYS . N . NANCE (1893 - 1964)

• Born on August 14, 1893 in Jackson , Tennesse.

• He was the Youngest of the five children.

• Upon the death of his mother in 1908 he attented the famed Webb School in Bell Buckle , Tennesse.

• While working in a copper mine in Miami , he suffered a fall resulting in several fractures and spinal injury . After a long convalescence during which he was obliged to wear a steel brace, he made a complete recovery.

• Following his marriage , he decided to enter the profession of dentistry and graduated from the North Western University in 1919.

• After practicing briefly in Arizona, he moved to Denver where he opened his own office

• In 1928 he moved to LA, practising for a number of years before moving to Pasadena where he remained until a Heart attack forced his retirement in 1948

• He is best known for his paper entitled “Limitation of Orthodontic Treatment” , which appeared in April, 1947.

• The Orthodontic Specialty, in recognition of Hay’s services over the years, conferred upon him Albert H. Ketcham Memorial Award in 1963.

• It was a fitting climax to Dr. Nance career, before he passed away due to heart attack at his home in Pasadena , California, 1964.

NANCE ANALYSIS• For patients with malalignment of teeth resulting

from lack of space, it is important to determine from the study casts the amount of crowding in the maxillary and the mandibular arch.

• For this two measurements are required in each arch

a) calculation of space required

b) calculation of space available

MATERIALS REQUIRED :• Sharp Divider

• Brass wire 0.010 inch in diameter

• Study Models

• A ruled 3 x 5 inch card for recording measurements

PROCEDURE :STEPS ARE AS FOLLOWS• Recording the mesio-distal width of each tooth

mesial to the first permanent molar using the divider. Sum total corresponds to the necessary space required.(Ideal Arch Length)

• Recording the actual arch length using a soft wire. This is contoured to the individual arch shape and placed on the occlusal surfaces over the contact points of the posterior teeth and the incisal edges of the anteriors

INFERENCE :

• The assessment of space relationship is the result of the difference between the ideal and actual arch length.

Negative Value shows “space deficiency”.

Positive Value shows “space excess”.

MILLS & HAMILTON ANALYSIS

MILLS & HAMILTON ANALYSIS• It was put forward by Loren F. Mills and Peggy M.

Hamilton in 1965.

• They devized a mathematical method for computing the arch perimeter by means of arch width and length measurement, after a study done on over 500 maxillary stone casts, obtained from the US Naval Academy, Annapolis, Maryland. Of this 362 casts were selected with a full complement of permanent teeth mesial to the first permanent molar.

• This technique is best suited for the following :

a) Population studies contrasting the size and shape of the jaws with effects of such variables, as ancestery, race, nutrtion, climate, or other environmental factors.

b) Malocclusion studies which estimate the space available for teeth and the effects of faulty mouth habits on jaw size.

They related the maxillary outline form with that of a parabola. Other recognised forms, such as square and ‘V’ shape , are present but do not occur too frequently in the general population

• The advantages of a mathematical parabola are as follows :

a) All are essentially alike

b) By a proper choice of scales and axes any parabola can be made to coincide with any other.

• They gave the formula to calculate the ARCH PERIMETER as :

Where, x = arch length

y = intermolar arch width

MEASUREMENT OF ARCH WIDTHA Korkhaus # 14 three dimensional orthodontic calliper is used to measure the arch width , from a pencil inscribed point at the gingivo-incisal margin of first molar at a point bisected by a line formed by the buccal fissure.

MEASUREMENT OF ARCH LENGTH• It is obtained by measuring the distance from a

line joining the midpoint of a line drawn from the distal surfaces of first molars to the interdental pappila of the central incisors

• Mill’s and Hamilton’s study compared this type of arch perimeter calculation with measured orthodontic archwire, the results showed measured wire technique had “six times” greater error than the mathematical method.

• The main advantage of this method of arch perimeter measurement is that it is far less time consuming than direct measurement.