Biomaterial Database

Incidence and features of three-rooted permanent mandibular molars. 1990

H S Loh

Department of Oral and Maxillofacial Surgery, National University of Singapore.

Seven hundred and eighty-six patients of Singaporean Chinese origin requiring extractions of permanent mandibular molars were screened. Personal details, identification of the tooth and the presence or absence of an extra root were recorded. Thirty-two cases (4.1 per cent) exhibited an extra disto-lingual root. None was found in the second molar. The first molar was affected (7.9 per cent) slightly more than twice as often as the third molar (3.7 per cent). The extra root was present almost equally in both sexes with a higher presentation on the left side. Six cases had a fracture of the extra root. A comparison was made with a study done by Tratman' on the same population and with other studies involving those of Chinese and Mongoloid origin in other countries.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008334	Mandible	The largest and strongest bone of the FACE constituting the lower jaw. It supports the lower teeth.	Mylohyoid Groove,Mylohyoid Ridge,Groove, Mylohyoid,Grooves, Mylohyoid,Mandibles,Mylohyoid Grooves,Mylohyoid Ridges,Ridge, Mylohyoid,Ridges, Mylohyoid
D008963	Molar	The most posterior teeth on either side of the jaw, totaling eight in the deciduous dentition (2 on each side, upper and lower), and usually 12 in the permanent dentition (three on each side, upper and lower). They are grinding teeth, having large crowns and broad chewing surfaces. (Jablonski, Dictionary of Dentistry, 1992, p821)	Molars
D008964	Molar, Third	The aftermost permanent tooth on each side in the maxilla and mandible.	Tooth, Wisdom,Teeth, Wisdom,Molars, Third,Third Molar,Third Molars,Wisdom Teeth,Wisdom Tooth
D002681	China	A country spanning from central Asia to the Pacific Ocean.	Inner Mongolia,Manchuria,People's Republic of China,Sinkiang,Mainland China
D005260	Female		Females
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012846	Singapore	Country of islands in Southeastern Asia, islands between Malaysia and Indonesia. The capital is Singapore.
D014082	Tooth Fractures	Break or rupture of a tooth or tooth root.	Fracture, Tooth,Fractures, Tooth,Tooth Fracture
D014092	Tooth Root	The part of a tooth from the neck to the apex, embedded in the alveolar process and covered with cementum. A root may be single or divided into several branches, usually identified by their relative position, e.g., lingual root or buccal root. Single-rooted teeth include mandibular first and second premolars and the maxillary second premolar teeth. The maxillary first premolar has two roots in most cases. Maxillary molars have three roots. (Jablonski, Dictionary of Dentistry, 1992, p690)	Root, Tooth,Roots, Tooth,Tooth Roots