The mandibular permanent second molars and their risk of impaction: a retrospective study

Authors:

ABSTRACT

Aim

The aim of this retrospective study is promote a better understanding of the impaction of teeth 37 and 47 by means of
clinical and statistical data from the point of view of early interceptive treatment.

Methods

Study Design: 478
patients of the Orthodontic School of "La Sapienza" University of Rome (Italy) were studied to assess the eruption of teeth 37 and 47 on
at least two good-quality panorex using angular measurements and Nolla's index from January 2008 to December 2013. Data were
analysed using ANOVA and Tukey HSD test (P < 0.05).

Results

The data obtained on the possible correlations between the
examined teeth and the four reference angles show that at t0, the angular variation of teeth 36 or 46 is constant when the teeth are at
the end of their eruptive process, while for teeth 37 and 47, this variation is always constant. At t0, the first and the second molars of
both quadrants, during eruption showed a similar behaviour. At t1, the four teeth examined in the patients sample showed a model of
development analogous to that exhibited at t0. Statistics: a constant variation (t0-t1) is present among the differences in the
development of the 36 and the two angular values, while difference in development of the 37 and that of the angular value is constant
only in relationship to the difference in development of the mandibular first molar of the same quadrant. The variations between the
difference in development of the 47 and in angular value (t0-t1) are constant only when related to the developing 46. The analytic
variance of gradience (vargrad) data confirm peculiar behaviour of the first one, according to both mandibular molars, during their
eruptive development. CONCLUSIONS: Adoption of universally recognised radiographic predictive methods allows assessment of the
case and allows the specialist to plan a suitable treatment to prevent or intercept the molar impaction, with a perspective of a less
invasive and shorter therapy. Although rare, impaction of teeth 37 and 47 often requires a complex, multidisciplinary
approach.

PLUMX METRICS