MORPHOMETRIC ANALYSIS OF THE MANDIBULA IN SHEEP, GOAT AND RABBIT

Understanding the morphological and morphometric properties of the mandible is crucial for the selection of an appropriate animal model for applications including implants, screws, prostheses, or bone defects. The purpose of this study is to present morphological data concerning the geometrical properties of the mandible in rabbits, sheep, and goats, which are used as models in experimental oral surgery. Length and height measurements of the mandibles were made on x-ray images of the mandibles. The cortical thicknesses and inner-outer diameters were also measured on the CT sectional images. In comparison to ruminants, the mandibular canal in rabbits is relatively shorter. In rabbits, the mental foramen is positioned caudally and closer to the molar teeth, while in sheep and goats, it is located rostrally and closer to the incisive teeth. In addition, the incisive roots are very extended and curved in rabbits and extend to the caudal border of the diastema. In ruminants, the incisive tooth roots are shorter and terminate close to the rostral border of the diastema, and there is a wider working area. Sheep and goats have wider and thicker bones in the rostral, intermediary and caudal regions of the mandible. The ramus region of rabbits has a thin bone structure, which makes it difficult to apply screws and other devices. The lateral side has a thicker cortical bone towards the rostral of the rabbit mandible, while the medial side is thicker in ruminants. The morphologic and geometric data of the mandible may support a study with critical size defects and screw, plate, or other implantations in rabbits and small ruminants to avoid problems or mistakes during experimental oral surgery. Also, the supplementary files can be used by researchers to investigate mandible x-ray images and CT sections of that animal species, as well as sections in different planes based on the intended position during pre-operative planning. Morfometrična analiza spodnje čeljustnice pri ovci, kozi in kuncu Izvleček: Razumevanje morfoloških in morfometričnih lastnosti spodnje čeljustnice je ključno za izbiro ustreznega živalskega modela za uporabo, vključno z vsadki, vijaki, protezami ali kostnimi defekti. Namen študije je predstaviti morfološke podatke o geometričnih lastnostih spodnje čeljustnice pri kuncih, ovcah in kozah, ki se uporabljajo kot modeli v eksperimentalni oralni kirurgiji. Meritve dolžine in višine čeljusti so bile opravljene na rentgenskih posnetkih spodnje čeljustnice. Debeline kompaktne kostnine ter notranji in zunanji premeri so bili izmerjeni tudi na CT-posnetkih prereza. V primerjavi s prežvekovalci je čeljustni kanal pri kuncih relativno krajši. Pri kuncih je bradna odprtina postavljena kavdalno in bližje molarnim zobem, medtem ko je pri ovcah in kozah postavljena rostralno in bližje sekalcem. Poleg tega so korenine sekalcev pri kuncih zelo podaljšane in ukrivljene ter segajo do kavdalnega roba diasteme. Pri prežvekovalcih so korenine sekalcev krajše in se končajo blizu rostralnega roba diasteme, delovno območje pa je širše. Ovce in koze imajo širše in debelejše kosti v rostralnem, vmesnem in kavdalnem področju spodnje čeljustnice. Področje ramusa spodnje čeljustnice ima pri kuncih tanko kostno strukturo, kar otežuje uporabo vijakov in drugih pripomočkov. Stranski del ima debelejšo kortikalno kost proti rostralnemu delu kunčje spodnje čeljustnice, medtem ko je medialna stran pri prežvekovalcih debelejša. Morfološki in geometrijski podatki o spodnji čeljusti lahko podpirajo študijo z defekti kritične velikosti in implantacijo vijakov, ploščic ali drugih pripomočkov pri kuncih in malih prežvekovalcih, da bi se izognili težavam ali napakam med eksperimentalno oralno kirurgijo. Prav tako lahko raziskovalci med načrtovanjem pred operacijo dodatne datoteke uporabijo za raziskovanje rentgenskih posnetkov spodnje čeljustnice in CT-rezine teh živalskih vrst ter rezin v različnih ravninah glede na predvideni položaj. Ključne besede: spodnja čeljustnica; anatomija; meritve; živalski modeli; eksperimentalna oralna kirurgija