Incisor procumbency

Following the approach direction of the incisors incisors in mammals, especially in rodents, distinguished in the premaxilla, which form a right angle ( orthodontics ), forming an obtuse angle ( Proodontie ) or an acute angle ( Opisthodontie and Hyperopisthodontie ) with the skull axis. The mapping is determined by the position of the cutting edge relative to the vertical plane of the tooth, which passes through the leading edge of the dental tray and perpendicular to the basal plane of the tooth. The difference between the Condylobasallänge and Condyloincisivlänge can serve as a measure of the degree of Proodontie or Opisthodontie.

Orthodontics

The orthodontic incisors ( from Ancient Greek ὀρθός Orthos, upright, straight ' and ὀδόντος odontos, teeth ' ) form with the skull axis at a right angle. Its cutting edge lies in the vertical plane of the tooth. Condylobasallänge and Condyloincisivlänge agree about equal to each other. The orthodontic incisors are found for example in wood mice.

Proodontie

Proodonte or proklivische incisors ( from Ancient Greek πρό pró, forward, forward " and ὀδόντος odontos, teeth ' or Latin proclivis, downhill ') form an obtuse angle with the skull axis. Its cutting edge lies in front of the vertical plane of the tooth. Which is smaller than the Condylobasallänge Condyloincisivlänge. Proodonte incisors are found mainly in burrowing rodents that loosen the soil with the incisors, such as terrestrial forms of the Vole.

Opisthodontie

Opisthodonte incisors ( from Ancient Greek ὄπισθεν opisthen, rear, from behind ' and ὀδόντος odontos, teeth ' ) form of the skull axis at an acute angle. Its cutting edge is positioned behind the vertical plane of the tooth. Which is greater than the Condylobasallänge Condyloincisivlänge. Opisthodonte incisors are found for example in many gerbils.

Hyperopisthodontie

Hyperopisthodonte incisors ( from Ancient Greek ὑπέρ hyper, over ', opisthen ὄπισθεν, rear, from behind ' and ὀδόντος odontos, teeth ' ) form of the skull axis at an acute angle. However, unlike opisthodonten incisors their cutting edge also lies behind the plane passing through the posterior margin of the tooth socket vertical plane of the tooth. Hyperopisthodonte incisors are found in some Sigmodontinae.

Used literature

• Jochen Niethammer, Franz Krapp (Eds. ): Handbook of the Mammals of Europe. Volume 1: Rodents I. Academic Publishing Company, Wiesbaden 1978, ISBN 3-400-00458-8.
• Scott J. Steppan: Revision of the Tribe Phyllotini ( Rodentia: Sigmodontinae ), with a Phylogenetic Hypothesis for the Sigmodontinae. In: Fieldiana Zoology. No. 80, 1995, ISSN 0015-0754, pp. 1-112 ( BHL: 21401 ).

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