The prevalence of craniomandibular disorders and occlusal disharmonies in the identical twins

Abstract

Objective. The aim of this study was to determine the prevalence of craniomandibular disorders (CMD) and occlusal disharmony in identical twins. Methods. Craniomandibular and occlusal disharmony, in a population of 30 pairs of identical twins, aged 20-40 years, with the same gender, were determined by history and functional analysis. The final evaluation was performed using estimation of dysfunction index (Di) and occlusal index (Oi). Results. In study sample 23 twins (38.3%) had a sign of craniomandibular dysfunction, and 33 (55%) of twins had occlusal abnormalities, such as incompatibility of mid dental arches with intercuspal relation -ICP, lack of contact with the antagonists in the ICP, the presence of occlusal interference or loss of teeth. The analysis of the representation of certain craniomandibular signs in 23 patients in whom the index dysfunction (Di) by Helkimo was greater than zero revailed the prevailing disturbed kinetics of the mandible (44.0%), the sound in the TMJ with movements of the mandible (22.0%) and deviation when opening the mouth (22.0%). Positive occlusal index was in 33 (55%) patients, of whom 24 (40%) had mild occlusal disharmony (Oi I = 1), and 9 (15%) patients had the pronounced occlusal discrepancies (Oi II = 2). Conclusion. The comparative analysis of craniomandibular disorders and occlusal status, in identical twins, has shown that occlusal factors play an important role in the etiology of craniomandibular dysfunction.

Cilj. Cilj istraživanja je da se utvrdi učestalost kranio­mandibularnih disfunkcija (CMD) i okluzalnih disharmonija, kod jednojajčanih blizanaca. Metode. Kraniomandibularne i okluzalne disharmonije, u populaciji 30 parova jednojajčanih blizanaca, starosti od 20 do 40 godina, podjednake polne pripadnosti,utvrđivane su anamnezom i funkcionalnom analizom. Konačna evaluacija izvršena je procenom indeksa disfunkcije (Di) i okluzalnim indeksom (Oi). Rezultati. U studijskom uzorku, 23 blizanca (38.3%) ima neki znak kraniomandibularnih disfunkcija, a 33(55 %) blizanca ima okluzalne nepravilnosti, kao što su nepodudarnost sredine zubnih nizova u interkuspalnom odnosu, odsustvo kontakata sa antagonistima u IKP odnosu, prisustvo okluzalnih smetnji ili gubitak zuba. Analizom zastupljenosti pojedinih kraniomandibularnih znakova, kod 23 ispitanika kod kojih je indeks disfunkcije (Di) po Helkimu veći od nule, preovlađuju poremećena kinetika donje vilice (44.0%), zvuk u TMZ, pri pokretima mandibule (22.0%) i devijacija pri otvaranju usta (22.0%). Pozitivan okluzalni indeks ima 33 (55%) ispitanika, od kojih 24 (40%) sa blagim okluzalnim disharmonijama (Oi I=1), a 9 (15%) ispitanika se izdvaja, po izrazitim okluzalnim diskrepancama (Oi II=2). Zaključak. Uporednom analizom kraniomandibularnih poremećaja i okluzalnog statusa, kod identičnih blizanaca, dokazano je da okluzalni faktori imaju značajnu ulogu u etiologiji kraniomandibularnih disfunkcija.