?研究人員稱,，用蛋白質(zhì)包裹的鈦義齒能夠誘導骨骼重建,，這項技術可能成為治療牙齦疾病導致牙齒缺損的一大技術進步。
??MCG牙科學校的研究人員將一種蛋白質(zhì)涂布于義齒表面,，實驗表明該方法能夠使得內(nèi)源性干細胞轉(zhuǎn)化為成骨細胞,。MCG牙科學校的牙周病學教授Ulf Wikesjö博士稱，試驗結果表明缺損組織幾乎被完全重建,。牙齒脫落和骨骼缺損是牙齦疾病常見的破壞性后果,。
??Wikesjö博士今年從費城坦布爾大學來到MCG牙科學校，他將對損傷修復和組織再生進行研究,，他的研究獲得了Nobel Biocare公司140萬美元的資助,，Nobel Biocare公司是牙科植體和牙科儀器的著名制造商。Wikesjö博士說：“在過去的二十年里,，我們一直致力于牙齦疾病所導致的牙周組織缺損的再生研究,，我們已經(jīng)通過幾種方法成功重建了受損組織。這些方法包括骨移植,、牙根修復及使用誘導組織生長的膜設備等,，所有的方法都使組織得到了修復。但是我們還必須調(diào)查哪些方法能夠適用于普通老百姓,。”
??經(jīng)過研究,，Dr. Wikesjö博士和他的同事發(fā)現(xiàn)，任何組織的再生都需要兩個條件：穩(wěn)定的創(chuàng)面和組織在修復起始階段再生時所需要的空間 “如果滿足以上兩個條件后,，那么牙周組織就會在1-2周的時間內(nèi)開始重建,，組織開始重建后的過程是一個復雜過程。”研究人員對一些材料對骨缺損再生的影響進行了研究,，他們發(fā)現(xiàn)一些材料,，包括現(xiàn)在使用的一些材料，實際上對組織再生起阻礙作用,。Dr. Wikesjö說：“一些象羥磷灰石顆粒這樣的生物材料,，雖然其化學成份與骨骼的礦物組成相似，但是實際上這些材料影響組織的再生,。因為這些材料不能被足夠迅速的吸收,，因此就可能占用新組織生長所需要的空間，從而阻礙新生組織的生長,。”
??研究人員通過試驗最終確定,，選用一種蛋白質(zhì)促使干細胞轉(zhuǎn)變?yōu)楣切纬杉毎姆椒▉硇迯蛽p傷組織。這種蛋白質(zhì)被稱為morpheonetic蛋白,，它已經(jīng)在顱面骨重建中取得了良好效果,。Dr. Wikesjö博士說：“以前morpheonetic蛋白被用于顱面部骨骼的重建,，我們從來沒有考慮到使用它對牙齒缺損進行治療。”為了驗證這種可行性,，研究人員將morpheonetic蛋白分別放置在動物模型的牙周和義齒上進行試驗,。
??將morpheonetic蛋白放置在牙周的試驗結果顯示，成骨細胞長入固有的骨骼中,，并且在形態(tài)上和骨骼完全一樣。然而,，牙根卻被新生骨的替代所破壞,，這個過程影響了其它重要牙周組織的再生。
??而將morpheonetic蛋白包裹在義齒上的試驗則獲得較好的效果,。再生的骨組織與牙植體表面緊密結合,，最終與牙齦內(nèi)的固存骨組織結合，這有利于牙齦組織的再生,。
??Wikesjö博士表示下一步將利用這種蛋白包裹的牙植體進行臨床試驗,。Wikesjö博士說：“我們還有許多東西需要研究。比如,，有時牙植體上的蛋白釋放過快,，而有時候則釋放過慢，我們需要找到影響這些問題的因素,。最終我們可能不需要太多的morpheonetic蛋白就可以使用這種蛋白包被的義齒發(fā)揮有效的作用,，我們期望能夠早日實現(xiàn)我們的愿望。”
英文原文：
Protein-coated dental implants could improve bone regeneration
Titanium dental implants coated with proteins that induce bone formation may be a key advancement in treating tooth loss due to gum disease, researchers say.
In laboratory tests, Medical College of Georgia researchers applied a protein onto implants that directs endogenous stem cells to become bone-forming cells. The result was a nearly complete regeneration of lost tissue, says Dr. Ulf Wikesjö, a professor of periodontics in MCG’s School of Dentistry.
Loss of teeth and bone is a common and devastating result of gum disease.
Dr. Wikesjö, who came to MCG this year from Temple University in Philadelphia, is researching wound-healing and tissue regeneration with a $1.4 million grant from Nobel Biocare, a leading manufacturer of dental implants and equipment.
Finding the key to improved regeneration is like piecing together a puzzle, Dr. Wikesjö says.
“For the past 20 years, there has been a quest to regenerate tissues around teeth that are lost due to periodontal disease,” he says. “I’ve looked at multiple approaches to achieve regeneration, including bone grafts, root conditioning and membrane devices for directed tissue growth, all resulting in some regeneration. Where we had to look was at the commonalities among these treatments.”
Dr. Wikesjö and his colleagues found that any regeneration requires two characteristics: a stable wound and space for the regenerated tissue to grow during the initial stages of healing.
“If these components are in place, regeneration of the tissues around the tooth may occur within a week or two,” he says. “After that, it’s a matter of the wound maturing – going through the various stages of healing that we’re already familiar with.”
By experimenting with treatments and discerning their effect on healing bone defects, they found some – including some in use today – that actually hinder tissue regeneration.
“Some biomaterials like hydroxyapatite particles, which are chemically similar to the mineral component of bone, may actually interfere with regeneration,” Dr. Wikesjö says. “They may not resorb quickly enough and may block the space for new tissue to grow into.”
The experiments helped researchers narrow down possible treatments to the use of proteins that directed stem cells to become bone-forming cells. Those proteins – called bone morpheonetic proteins – have already shown promise as a regeneration therapy for craniofacial reconstruction.
“None of us had any idea at the time how or if those proteins could be useful in treating tooth loss,” Dr. Wikesjö says.
To find out, researchers placed the proteins around teeth and implants in animal models.
Around teeth, the bone-forming cells grew into existing bone and eventually morphed into bone themselves. However, the root of the tooth was destroyed by the replacement bone. That process impeded regeneration of other essential tissues around the tooth.
Applying the protein to implants proved more beneficial.
“There was almost complete regeneration,” he says. “The generated bone bonded with the implant’s surface and, eventually, existing bone in the gums. That allowed for the regeneration of gum tissues.”
The next step is clinical trials of an implant coated with the proteins, which Dr. Wikesjö hopes to start this summer.
“There are still things we need to learn. In some cases, the protein may rapidly release from the implant, and other times, there appears to be a more gradual release,” Dr. Wikesjö says. “We need to find out what factors cause that. In the end, we may not need to use much protein to make the implant effective. Those are things we’re looking at now.”
