Dentoalveolar Characteristics in Subjects with Anterior Open Bite

Svrha ovoga rada bila je utvrditi izraženost dentoalveolarnih kompenzatornih mehanizama u ispitanika s otvorenim zagrizom u usporedbi s eugnatim ispitanicima. Ispitivanje je provedeno na 37 latero-lateralnih rentgenkefalograma pacijenata s otvorenim zagrizom i na 35 eugnatih ispitanika u dobi od 15 do 18 godina. Svaki rentgenkefalogram iscrtan je dva puta od dvaju autora. Rentgenkefalometrijska raščlamba sastojala se od mjerenja angularnih i linearnih parametara. Angularne varijable bile su: n-s-gn, sp-pm:mgo, m-go-ar, suma kuteva prema Bjorku, 1:sp-pm i 1:m-go. Linearne varijable oi, om, oi/om, ui, um, i ui/um uzete su iz Korkhausove analize. Statistička raščlamba obuhvatila je deskriptivnu statistiku, metodsku pogrešku, t-test i Pearsonov koeficijent korelacije. Statistički znatne razlike (p<0,001) između ispitivanih skupina pronađene su kod svih ispitivanih varijabli osim 1:sp-pm, oi/om i um. Pronađena je retruzija donjih sjekutića, što upućuje na dentoalveolarnu adaptaciju na postojeću posteriornu rotaciju čeljusti. Inklinacija gornjih inciziva je u odnosu prema bazi maksile u znatnoj negativnoj korelaciji s varijablom n-s-gn, i u laganoj negativnoj korelaciji s varijablom sppm: m.go. Varijable visine gornje i donje čeljusti (oi, om, ui, um) u znatnoj su međusobnoj korelaciji. Znatna negativna korelacija pronađena je između varijabli um i m-go-ar. Korelacija između varijable um i Bjorkova poligona lagana je i negativna. Varijabla ui pokazuje laganu negativnu korelaciju s varijablom m-go-ar. Takav odnos rezultat je kompenzatorne retruzije donjih inciziva na strmu mandibularnu ravninu.The purpose of this study was to determine the frequency and extent of dentoalveolar compensation in subjects with disharmonious vertical jaw base relationships, in relation to subjects with normal occlusion. The study was performed on 37 lateral cephalograms of patients with open bite and 35 of patients with normal occlusion, aged 15 to 18 years. Each cephalogram was traced twice by two authors. The cephalometric analyses were performed by linear and angular measurements. The angular cephalometric variables were: n-s-gn, sp-pm:m-go, m-go-ar, the sum of the posterior angles according to Bjork (1947, 1954,1966,1972),1:sp-pm and 1:m-go. Linear cephalometric variables: oi, om oi/om, ui, um and ui/um were analysed using the methods of Korkhaus (1959). Statistical data analysis included descriptive statistics, method error, t-test and Pearson(s correlation coefficient for association between variables. Significant differences (p < 0.001) between the samples were found in all investigated variables except 1:sp-pm, oi/om and um. Retrusion of the lower incisors was found, indicating dentoalveolar adaptation to the present posterior rotation of the mandible. Inclination of the upper incisors in relation to the base of the maxilla was significantly negative correlated with the variable n-s-gn, and slightly negatively by correlated with the variable sp:pmm-go. The variables of the height of the upper and lower jaws (oi, om, ui, um) were significantly correlated. A significiant negative correlation was found between variables um and m-go-ar. The correlation between variable um and Bjork’s polygon was slightly negative. The variable ui showed slight negative correlation with the variable m-go-ar. Such a relationship is the result of compensatory retrusion of the lower incisors and a steep mandibular plane