自從幹細胞的研究範圍日益擴大，智齒的牙髓也被發現是成體幹細胞(post-natal stem cell)的來源之一。如此一來，智齒拔除的理由及時機似乎又多了一項考慮。在牙齒發育胚胎學上有有所謂bud stage, cap stage, bell stage，在late bell stage才開始有鈣化產生，也才能在X光片上被觀察到。本實驗的目的在於比較不同發育時期智齒牙胚中間葉幹細胞其菌落形成單位的量。在符合智齒移除適應症的患者X光片上依牙根發育階段將案例分為鐘型(bell stage) (group 1) 、 牙根形成1/2前(group 2)、牙根形成3/4(group 3) 、根尖未閉合(group 4)、根尖已閉合5群(group 5)。依標準口腔外科程序取出智齒，取出牙冠下軟組織，進行細胞培養; 探討初代細胞(P 0) 其菌落形成單位的量,在不同發育時期的表現，結果發現群落形成單位與組織重量成正相關; group 5無群落形成單位。

Post-natal stem cells originated from pulp of wisdom teeth may be applied for regenerative medicine. The reason and timing for wisdom teeth removal should be re-evaluated. In the aspect of embryology, teeth develop through bud stage, cap stage, bell stage, and then root formation. Our aim is to compare the quantity of CFU in cells isolated from pulp tissue or germ of human wisdom teeth at different developmental stages. Clinically, we can see the developing teeth in radiographs only until calcification of tissue in the late bell stage. We divided patients' teeth into 5 groups: bell stage (group 1), 1/2 root formation (group 2), 3/4 root formation (group 3), well-formed root but open apex (group 4), well-formed root with closed apex (group 5), according to patients' panoramic films. If patients fit the indication of wisdom teeth removal, teeth were removed by a standard oral surgical procedure and the soft tissues inside the crown were taken. After enzymatic dissociation of these soft tissues, we isolated cells from them and performed the primary cell culture. Positive correlation between CFU and tissue weight was noted. But colony was not observed in the group 5.

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