?研究人员称，用蛋白质包裹的钛义齿能够诱导骨骼重建，这项技术可能成为治疗牙龈疾病导致牙齿缺损的一大技术进步。
??MCG牙科学校的研究人员将一种蛋白质涂布于义齿表面，实验表明该方法能够使得内源性干细胞转化为成骨细胞。MCG牙科学校的牙周病学教授Ulf Wikesjö博士称，试验结果表明缺损组织几乎被完全重建。牙齿脱落和骨骼缺损是牙龈疾病常见的破坏性后果。
??Wikesjö博士今年从费城坦布尔大学来到MCG牙科学校，他将对损伤修复和组织再生进行研究，他的研究获得了Nobel Biocare公司140万美元的资助，Nobel Biocare公司是牙科植体和牙科仪器的著名制造商。Wikesjö博士说：“在过去的二十年里，我们一直致力于牙龈疾病所导致的牙周组织缺损的再生研究，我们已经通过几种方法成功重建了受损组织。这些方法包括骨移植、牙根修复及使用诱导组织生长的膜设备等，所有的方法都使组织得到了修复。但是我们还必须调查哪些方法能够适用于普通老百姓。”
??经过研究，Dr. Wikesjö博士和他的同事发现，任何组织的再生都需要两个条件：稳定的创面和组织在修复起始阶段再生时所需要的空间 “如果满足以上两个条件后，那么牙周组织就会在1-2周的时间内开始重建，组织开始重建后的过程是一个复杂过程。”研究人员对一些材料对骨缺损再生的影响进行了研究，他们发现一些材料，包括现在使用的一些材料，实际上对组织再生起阻碍作用。Dr. Wikesjö说：“一些象羟磷灰石颗粒这样的生物材料，虽然其化学成份与骨骼的矿物组成相似，但是实际上这些材料影响组织的再生。因为这些材料不能被足够迅速的吸收，因此就可能占用新组织生长所需要的空间，从而阻碍新生组织的生长。”
??研究人员通过试验最终确定，选用一种蛋白质促使干细胞转变为骨形成细胞的方法来修复损伤组织。这种蛋白质被称为morpheonetic蛋白，它已经在颅面骨重建中取得了良好效果。Dr. Wikesjö博士说：“以前morpheonetic蛋白被用于颅面部骨骼的重建，我们从来没有考虑到使用它对牙齿缺损进行治疗。”为了验证这种可行性，研究人员将morpheonetic蛋白分别放置在动物模型的牙周和义齿上进行试验。
??将morpheonetic蛋白放置在牙周的试验结果显示，成骨细胞长入固有的骨骼中，并且在形态上和骨骼完全一样。然而，牙根却被新生骨的替代所破坏，这个过程影响了其它重要牙周组织的再生。
??而将morpheonetic蛋白包裹在义齿上的试验则获得较好的效果。再生的骨组织与牙植体表面紧密结合，最终与牙龈内的固存骨组织结合，这有利于牙龈组织的再生。
??Wikesjö博士表示下一步将利用这种蛋白包裹的牙植体进行临床试验。Wikesjö博士说：“我们还有许多东西需要研究。比如，有时牙植体上的蛋白释放过快，而有时候则释放过慢，我们需要找到影响这些问题的因素。最终我们可能不需要太多的morpheonetic蛋白就可以使用这种蛋白包被的义齿发挥有效的作用，我们期望能够早日实现我们的愿望。”
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.”
