Mandibular torus morphology

Abstract

The morphology of the mandibular torus was examined, and comparisons were made between a Medieval Norse skeletal population from Greenland and a 14th to 17th century Greenland Eskimo skeletal series. Three parameters were analyzed: degree of development (on a 4-point scale), position and length, and surface morphology according to the number of knobs, or lobuli. It was found that the Eskimos have a high frequency of weakly developed tori and no cases of the extreme development, while over 20% of the Norsemen had tori in the "extreme" category. The Norse torus was generally found to be longer than that of the Eskimos, and both groups exhibited a slight asymmetry between the sides, the torus on the left side tending to be longer and more forward in position than the right. A great difference was found in surface morphology. The Norse torus is in general very irregular, while the Eskimo torus is rather smooth. These differences are believed to be genetically determined.

Frequency of mandibular tori in the present-day Japanese

“…These results resemble those of Muller and Mayhall (1970), Schau- (1970), Mouri (1976), Sellevold (1980), and King and King (1981). Some studies showed that frequencies were significantly higher in males than in females (Alvesalo and Kari, 1972;Volchansky, 1986;Reichert et al, 1988;Eggen and Navig, 1991;Haugen, 1992;Sugihara et al, 2003).…”

“…Previous studies showed that mandibular torus frequencies tend to be high (from 50 to 100%) in the 'Frigid Zone' populations, either of Asians (Hrdlicka, 1940;Moorrees, 1957;Ossenberg, 1981;Dodo and Ishida, 1987) or Europeans (Hrdlicka, 1940;Sellevold, 1980) (Appendix 1). However, in some Frigid Zone populations frequencies were not so high (from 3 to 40%), either in Asian (Duckworth and Pain, 1900;Moorrees, 1957;Mayhall, 1968;Jarvis and Gorlin, 1972) or in European populations (Mellequist and Sandberg, 1939;Axelsson and Hedegard, 1981;Eggen and Natvig, 1991;Haugen, 1992).…”

“…Geographical distribution patterns suggest that the occurrence of mandibular tori cannot simply be explained by genetic or environmental factors. Some previous studies emphasized genetic factors as the cause of tori formation, based on comparisons of torus frequencies in genetically different populations living in similar environments (Moorrees, 1957;Sellevold, 1980), or by examining torus incidences in families (Suzuki and Sakai, 1960;Johnson et al, 1963;Alvesalo and Kari, 1972). Ossenberg (1981) reviewed previously published data and concluded that a threshold model could more fully explain the trait's phenotypic behaviors than a single gene model.…”

Exostoses buccales : revue de la littérature

“…Ces nodules sont le plus souvent juxtaposés horizontalement et situés au-dessus de la ligne mylo-hyoïdienne [28,31,76,[79][80][81][82]. Selon Kolas et al [28], dans le sens antéro-postérieur, les torus mandibulaires peuvent s'étendre de : − la région incisive à la région canine ; − la région incisive à la région prémolaire ; − la région incisive à la région molaire ; − la région canine à la région prémolaire ; − la région canine à la région molaire ; − la région prémolaire à la région molaire.…”

Frequency of Mandibular Torus in Jomon People, Medieval Japanese and Modern Japanese

“…Key words:mandibular torus, Jomon people, medieval Japanese, modern Japanese, degree of dental attrition 報 告 が 多 く (Hooton, 1918;Hrdlicka, 1940;Moorrees, 1957;Dodo, 1974;Sellevold, 1980;Ossenberg, 1981;Dodo and Ishida, 1987) ，上記以外の地域に住むヨーロッパ人 (Reichart et al, 1988)やアメリカ白人 (King and King, 1981) ，アメリカ黒人 (King and King, 1981) ，アフリカ黒 人 (Hrdlicka, 1940) ，南太平洋の集団 (Fenner, 1939)で は出現頻度が低いと報告されている。しかし，出現頻度 についての報告は，北米大陸を中心とした亜寒帯以北の 集団を対象にしたものが多く (Duckworth and Pain, 1900;Hooton, 1918;Mellquiast and Sandberg, 1939;Hrdlicka, 1940;Moorrees et al, 1952;Moorrees, 1957;Mayhall, 1968;Jarvis and Gorlin, 1972;Dodo, 1974;Kaul and Anand, 1979;Sellevold, 1980;Ossenberg, 1981;Dodo and Ishida, 1987;Eggen and Natig, 1991;Haugen, 1992 …”