A Comparative Analysis of the Mandibular Cinematically Determinated Hinge Axis and the Referent Hobo’s Point

Abstract

U istraživanju je sudjelovalo 48 ispitanika u dobi od 18 do 50 godina. Svakom ispitaniku je određena šarnirska os mandibule Lauritzenovom tehnikom i označena metalnom kuglicom promjera 1 mm na lijevoj strani lica. Hobo točka je određena mjerenjem i označena metalnom kuglicom promjera 0,5 mm na istoj strani lica. Za svakog ispitanika napravljen je telerentgenogram koji je precrtan na prozirni papir. Na svakom rentgenogramu su označene točke: porion, orbitale, Hobo i terminalna šarnirska os (THA). Spajanjem točaka porion i orbitale konstruirana je frankfurtska horizontala i izmjerene su udaljenosti između točaka Hobo i THA i između frankfurtske horizontale i točke THA. Statističkom obradom dobiveni su osnovni statistički pokazatelji i distribucija vrijednosti. Rezultati pokazuju da se u 68% slučajeva točka Hobo nalazi unutar radijusa od 5 mm od točke THA, pa je prema tome podjednako upotrebljiva za prosječno orijentiranje kao i ostale prosječne točke. Prosječna udaljenost točke THA i frankfurtske horizontale iznosila je 4,08 mm. Veliki pokazatelji varijabilnosti za obje promatrane varijable upozoravaju na potrebu individualnog pristupa svakom pacijentu.On a sample of 48 patients terminal hinge axis has been determined by use of Lauritzen’s technique. Terminal hinge axis point has been marked on the leftside of face of each patient with a metal pellet 0.5 mm in diameter. Hobo point has been measured and marked on the same side of face, for each patient, with a metal pellet 1.0 mm in diameter. Standard cephalometric roentgenogram was obtained for each patient. Cephalograms were traced on a transparent foil and points Porion, Orbitale, Hobo and terminal hinge Axis point (THA) have been marked. By connecting points Porion and Orbitale, Frankfort horizontal has been lined on each cephalogram. Distances between points Hobo and THA, as well as between Frankfort horizontal and. point THA have been measured. Measured values have been statistically evaluated. Results show that 68% of points Hobo are in diameter o f 5.0 mm from point THA. Accordingly to results point Hobo is equally usable for facebow mounting o f casts as well as any other arbitrary point. Mean value of distance between THA point and Frankfort horizontal in this investigation is 4.08 mm. Great standard deviation and coefficient of variation for both variables pointed out that each patient must be individually evaluated and treated