Zur Ätiologie der Eckzahnverlagerung — eine Platzanalyse

Abstract

The aim of this study was to examine to what extent excess space must be taken into consideration as an etiological factor in upper canine impaction with special attention paid to the role of the adjacent laterals. To clarify this question the pre- and post-treatment models of 63 patients with a total of 84 impacted cuspids were measured and the cephalograms of 116 patients having 144 impacted cuspids were analyzed. The results of this study revealed: 84.5% of the cuspids were palatally impacted while 15.5% were labially impacted. An arch deficiency was found in only 18% of the palatally impacted cuspids, whereas there was an arch-length deficiency in 46% of the buccally impacted. In 35% of the cases there was a correlation between peg shaped laterals and palatal impaction, however, such was not present in the patients with vestibular retention. Finally the cephalometric data revealed horizontal growth characteristics in 80% of the palatally impacted canines as opposed to 23% in those labially impacted.

Impacted upper canines: examination and treatment proposal based on 3D versus 2D diagnosis

“…This corresponds to 13.9% of all displaced teeth, which is only exceeded by wisdom teeth, with an incidence of 78% [14,32]. Possible causes for this displacement include protracted duration of the eruption, anatomically complex factors in the eruption path, crowding or excessive space in the upper jaw, the lack of guiding structures due to delayed root development, as well as hypoplasia or aplasia of the lateral incisor [7,11,13,32,38,42,46,47,48,52,55,58,60,65]. Other causes include injuries to the anterior teeth in early mixed dentition [18], Angle Class II, Division 2 [5,33,50], genetic factors [52,69], abnormal tooth germ position, ankylosis, follicular cysts, odontoma, and cleft lip and palate [11,13,32].…”

“…Palatal canine displacement is much more frequent than vestibular displacement (43-87% to 13-39%) [16,23,42,65,67]. Depending on the method of examination, resorptions of adjacent teeth can be detected in as many as 38% of patients with displaced upper canines [26].…”

The topography of displaced canines

“…The pixel size of the CT images varied between 0.20 and 0.48 mm. Between 175 and ruhen [9,45]. Betrachtet man nun die beiden Verlagerungsformen wie auch nicht verlagerte Eckzahnkeime, so fällt auf, dass auch innerhalb dieser Gruppen eine enorme anatomische Variabilität bezüglich der Angulation der Eckzahnachse existiert.…”

“…Nach der topographischen Lagebeziehung differenziert man zwischen nach bukkal und palatinal verlagerten Zähnen, wobei die Mehrzahl der verlagerten Eckzähne der Gruppe der nach palatinal verlagerten Zähne zugeordnet werden kann [9,45,50]. Beide Verlagerungsformen scheinen auf unterschiedlichen Entstehungsgrundlagen zu be-…”

“…Depending on their topographic position, a distinction is made between buccally and palatally displaced teeth; the majority of displaced canines are classified as being palatally displaced [9,45,50]. The two forms of displacement are thought to arise from different etiological factors [9,45]. When examining the two displacement forms and non-displaced canines, the enormous anatomical variability within each group in the angulation of the canine tooth axis is striking.…”