To-khí-chèng, Lan-san-khí, (Hàn-jī: 多齒症, Eng-gí: hyperdontia, supernumery tooth) hoat-goân chū khí-pán (dental lamina) lan-san ê tē-3 khí-phōe, lēng-gōa ê khó-lêng sī éng-kiú-khí khí-phōe ê hun-sin. To-khí-chèng tī éng-kiú-khí ū chhiau-kòe 2-pha ê hoat-seng-lu̍t, ah kî-tiong ū 75-pha hoat-seng tī téng-go̍k thâu-chêng-khí (anterior tooth), chèng-tiong chóe-seng-khí (mesioden) sī siōng-chiap khòaⁿ--tio̍h-ê. Kî-thaⁿ tiāⁿ-tiāⁿ khòaⁿ--tio̍h-ê sī téng-go̍k ê tē-4 éng-kiú tōa-kiū-khí, ē-go̍k tē-3 éng-kiú sió-kiū-khí, kap to-seng-sèng ê téng-go̍k chhek mn̂g-khí. Ū chhiong-hun chèng-kù hián-sī to-khí-chèng sī chū-thé-hián-sèng (autosomal dominant) ê ûi-thôan. Ni-khí khí-lia̍t chiâⁿ-chió hoat-seng chit-chióng chêng-hêng. Tī cleidocranial dysostosis kap Gardner syndrome tiong ē hoat-hiān tio̍h chhut-khí chiàng-gāi ê to-khí-chèng. To-khí-chèng kap pō·-hūn khiàm-khí ê khoat-khí kî-hêng ē kāng-sî hoat-seng.

lan-san-khí