Prevalence, types and etiologic factors of mandibular crowding in orthodontic patients in Tabasco, Mexico, 2015-2016

Resumen

Late mandibular crowding is a frequent malocclusion that develops between 15 and 20 years of age and has been associated with a number of etiological factors, mainly: the eruption of lower third molars, anterior tooth discrepancy, mandibular length and growth pattern. The aim of this investigation was to evaluate the prevalence, types and etiological factors of late mandibular crowding in orthodontic patients, in Tabasco, Mexico, 2015-2016. It was an observational, analytical, case-control study. The sample consisted of 74 new patients from the Postgraduate Clinic of Orthodontics of the Juárez Autonomous University of Tabasco who came to the clinic between August 2015 and December 2016. Clinical records, models and radiographs were reviewed. It was found that the prevalence of late mandibular crowding was 83.7%; the most common types were severe 26% and very severe 27%. Seventy percent of the patients showed more dentoalveolar discrepancy on the lower arch. Twenty six percent of patients with crowding showed reduced mandibular length. The horizontal growth pattern predominated in 49% of the case groups and in 58% of the controls. The C position of the third molars predominated on both sides. It was concluded that no patient with crowding had a diminished mandibular body or a vertical growth pattern. Crowding can occur regardless of whether or not the lower third molars are present.