Sabrina Mutinelli | PubMed Health

PubMed2006

Symmetry evaluation in the dental arch: the IXS index.

The aim of the present geometrical analysis is to find a method to evaluate the symmetrical position of the teeth inside the dental arch and the symmetry of the dental curve in general. The biggest problem was the identification of the symmetry axis of the upper and the lower dental arches, since there is an absence of certain anatomic landmarks in the centre of palate and mandibular body. Therefore the theorems of symmetrical figures have been applied in order to research the relationship between the dental arch points and to obtain an index: the Ixs Index. The Ixs Index gives a result of 1 when 2 couples, such as the cusps of the canines and the mesio-buccal cusps of the first molars, are in symmetric position. In contrast with a result unequal to 1, the teeth lie asymmetrically.

Dental Arch↗

PubMed2004

Dental arch analysis system.

The purpose of our research is to describe a computerized method, which enables orthodontists and researchers to analyze variation of dental arch form and dimension. The analysis system is composed of two independent parts: the database, where the images of scanned dental casts are stored, and the software. The operator uses the software to identify some landmarks on dental cast images. Corresponding distances are calculated (interincisive, intercanine and intermolar widths and the curve axis). Then the software algorithms calculate and draw the curves passing trough the selected landmarks (conics, catenary, cubic spline and polynomial curves). In the chosen curves the arch length is measured. The dental cast data, recorded at different times of the subject's life or in different steps of orthodontic treatment, are compared in order to evaluate the change in dimension (arch length and width) and form (shape). The statistical analysis of the data evaluates the variation in form and in dimension separately. The shape change is defined by Euclidean Distance Matrix Analysis (EDMA) and Bootstrap analysis. The computerized method allows orthodontists and researches to evaluate the variation in dimension and form of the dental arch in un-treated subjects and-or orthodontic patients over time. After the analysis of a large sample of patients or subjects, information concerning changes in dental arch dimension and form can be added to previous studies of other authors, distinguishing variation during and after orthodontic treatment, during growth or aging.

Cephalometry↗