重视和加强对口腔遗传性疾病的研究

There are many kinds of oral hereditary diseases. Although some attempts have been tried to find the genetics of those diseases,still fewer information are available than the other hereditary diseases at present. Much is needed to do in the future. This article reviewed some cutting-edge findings on the genetics of several oral hereditary diseases,including hereditary diseases involving the teeth, periodontal tissues, soft and hard tissues of the oral and maxillofacial region, as well as cleft lip and palate.     

The effect of splinting of teeth in combination with reconstructive periodontal surgery in humans

The purpose of this study was to evaluate the effect of splinting teeth on the results of periodontal reconstructive surgery using a specific carbonate bone replacement graft (BRG) material. Forty-five patients were randomly treated with a periodontal surgery approach. Natural coral calcium BRG was utilised in 33 patients. This 33-patient group was divided into three equal groups. In the presplint group, teeth were splinted to at least two rigid teeth before surgery, in the postsplint group, teeth were splinted at suture removal, and in the nonsplint group, the treated teeth were not splinted at all. In 12 patients, teeth were treated with surgical debridement (DEBR) alone and not splinted. Periodontal probing depth (PPD), clinical probing attachment level (CPAL), and tooth mobility were measured using desmodontometry (DDM) and periotest (PTV) with reproducible methods before surgery and at various periods up to 1 year afterwards . A decrease in PPD (5.4 mm, SD 1.4 mm) and tooth mobility (DDM-horizontal 257 μm, SD 60 μm) and a gain of CPAL (5.1 mm, SD 1.4 mm) were seen following the use of BRG in presplint teeth. In the same group, PPD and tooth mobility were significantly reduced compared to nonsplint teeth. DEBR alone showed reductions in tooth mobility and PPD and a significantly smaller gain in CPAL than in presplint teeth treated with BRG. The less favourable improvement in periodontal function of postsplint or nonsplint teeth seemed to be due to the loss of BRG material caused by tooth mobility. These results indicate that an undisturbed wound healing process using BRG together with tooth stability is beneficial to overall clinical success. Received: 30 October 1998 / Accepted: 18 January 2000     

Cell biology in orthodontic tooth movement： The known and the unknown

This review is aimed at providing, at the cellular level, a concise and complete overview ot the important knowledge on the mechanism of orthodontic tooth movement to orthodontists and postgraduates who are involved or interested in basic research. The construction of this article was oriented to the following key questions: Where an osteoclast starts to its first resorption site? When the cascade of a resorption cycle starts? What are the factors involved in bone remodeling and how they orchestrate? What happens before and after the formation of a resorption pit? Major findings in these aspects were summarized and discussed. In addition, related biological phenomenon such as orthodontically induced root resorption was intensively reviewed. By means of an updated and systematic review, the author intended to introduce more biological evidence to orthodontic intervention and to encourage evidence-based treatment in daily orthodontic practice.     

Molecular biology and its applications in orthodontics and oral and maxillofacial surgery

Molecular biology is an exciting, rapidly expanding field, which has enabled enormously greater understanding of the biology of diseases and malfunctions in many fields. It chiefly concerns itself with understanding the interactions between the various systems of a cell, including the interrelationship of DNA, RNA and protein synthesis and how these interactions are regulated. Since the introduction of molecular biology into modern science, numerous other fields have been enabled to go ““molecular““. Advanced molecular biological techniques showed us new avenue towards finding answers to the questions asked for decades. The first part of this article described the history of molecular biology. It started as a joined discipline of other areas of biology, i.e. genetics and biochemistry in the 1930s and 1940s, and enjoyed its classical period and became institutionalized in the 1950s and 1960s. Major molecular techniques manipulating proteins, DNA and RNA were introduced and their mechanisms were concisely illustrated. The current knowledge of molecular biology and their applications in orthodontic and oral and maxillofacial surgery, i.e. osteoclast differentiation and function, regulation of tooth movement, mechanotransduction/cell-signalling, bone fracture healing, oral cancer as well as craniofacial/dental anomalies and distraction osteogenesis were discussed. Although the problems of introducing molecular technologies are still substantial, it is anticipated that the future of medicine/dentistry will be ““molecular““: molecular prevention, molecular diagnosis and molecular therapy.     

口腔鳞癌组织中尿激酶型纤溶酶原激活剂及其抑制剂活性与颈淋巴结转移的关系

Chromogenic substrate assay was used to determine the activity of uPA and PAI-1 in tumor extract, their relationship with clinlcal and pathological parameters were analysed. It was found that activity of uPA and PAI-1 in tumor tissue was much higher than those in the corresponding normal tissue(P＜0.01); There was no relationship between activity of uPA and PAI-1 and size, histalogical classification of tumor, but the activity of uPA had positive relation to clinical stage; The uPA and PAI-1 activity in tumor with metastasis were significantly higher than those in nonmetastasis tumor(P＞0.01),furthermore, it was shown that uPA and PAI-1 in metastastic lymphnode were greatly higher than that in primary tumor. The result indicated elevation of activity of uPA and PAI-1 might be responsible for the metastasis to neck lymphnode.     

Reliability of the Brownish-flanked Bush Warbler’s soft song in male-male conflict

Background: Soft song is a low-amplitude song produced by many birds. Recent studies have confirmed that soft song is an aggressive signal. For example, the Brownish-flanked Bush Warblers Cettia fortipes use soft song in male-male conflicts, particularly prior to attacks. Although stable signaling systems require that signals be honest on average,models predict that cheating is an acceptable strategy for some individuals or in some contexts.Methods: This study aimed to test the reliability of soft song as an aggressive signal in the brownish-flanked bush warbler. We used mounted specimens accompanied by broadcast songs or soft songs to simulate a male attempting to invade an existing territory.Results: We found the mounted specimen that coupled playback of soft songs suffered more and quicker attacks from the territory owner and that the relationship between soft song and subsequent attack in the territory owner was far from perfect. We observed territory owners that both over-signaled(i.e., produced soft song but did not attack) and under-signaled(i.e., attacked without producing soft song). Under-signaling territory owners were relatively more commonly than were over-signaling territory owners, particularly in simulated intrusion that coupled playback of soft song with a mount specimen.Conclusions: We discuss the cost of producing soft song and the potential benefit of the unreliable use of soft song and propose a new hypothesis for under-signaling with soft song; i.e., under-signaling territory owners might benefit from taking the initiative in fights.     

Role of vascular endothelial growth factor in reconstructive surgery after surgical excision of malignant tumor

As a key mediator of normal physiological angiogenesis, vascular endothelial growth factor(VEGF) has been regarded as an emancipator to plastic surgeon, and yet a misfortune to oncology surgeon, due to its singular biological effect. Therefore in some clinical cases, especially for some malignant tumor patients having endured radical surgery and being craving for a reconstructive surgery, VEGF plays a role full of paradoxes. To make a clinical balance, we should find a point to inhibit tumor cell from utilizing VEGF and make a permission to normal tissues to employ it.     

Repair of large orbito-maxillofacial defects following resection of tumors with temporalis myofascial flap and facial-cervico-pectoral flap

PURPOSE: To evaluate the results of facial-cervico-pectoral rotation flap (FRF) and temporalis myofascial flap (TMF) in the repair of large soft tissue defect in oral and maxillofacial regions. METHODS: Six patients with malignant orbital tumors and/or maxillofacial tumors invading the orbital regions were treated with extensive resection. The major midfacial soft tissue defects were repaired by temporalis myofascial flap and facial-cervico-pectoral rotation flap. RESULTS: All flaps were successfully transferred; the result of facial aesthetics was satisfactory in all patients. Follow-up periods varied from 9 to 20 months (mean follow up period: 13.2 months) and all of the patients were alive during the follow-up period with one recurrence. CONCLUSIONS: The TMF and the FRF are easy to harvest, have low donor site morbidity, and are compatible with the principles of oncologic resection. It is the method of choice for repairing major orbito-maxillofacial skin defects following resection of the tumors.     

Bioengineered teeth from tooth bud cells

Advances in tissue engineering and materials science have led to significant progress in hard and soft tissue repair and regeneration. Studies demonstrate the successful application of tissue engineering for bioengineering dental tissues. The ability to apply tissue engineering to repair or regenerate dental tissues and even whole teeth is becoming a reality. Current efforts focus on directing the formation of bioengineered dental tissues and whole teeth of predetermined size and shape. Advances in dental progenitor cell characterizations, combined with improved methods of fabricating biodegradable scaffold materials, bring closer the goal of making tooth tissue engineering a clinically relevant practice.     

Regenerative endodontics as a tissue engineering approach: Past,current and future

With the reported startling statistics of high incidence of tooth decay and tooth loss, the current interest is focused on the development of alternate dental tissue replacement therapies. This has led to the application of dental tissue engineering as a clinically relevant method for the regeneration of dental tissues and generation of bioengineered whole tooth. Although, tissue engineering approach requires the three main key elements of stem cells, scaffold and morphogens, a conductive environment (fourth element) is equally important for successful engineering of any tissue and/or organ. The applications of this science has evolved continuously in dentistry, beginning from the application of Ca(OH)₂ in vital pulp therapy to the development of a fully functional bioengineered tooth (mice). Thus, with advances in basic research, recent reports and studies have shown successful application of tissue engineering in the field of dentistry. However, certain practical obstacles are yet to be overcome before dental tissue regeneration can be applied as evidence‐based approach in clinics. The article highlights on the past achievements, current developments and future prospects of tissue engineering and regenerative therapy in the field of endodontics and bioengineered teeth (bioteeth).     

Tooth agenesis: from molecular genetics to molecular dentistry

Tooth agenesis may originate from either genetic or environmental factors. Genetically determined hypodontic disorders appear as isolated features or as part of a syndrome. Msx1, Pax9, and Axin2 are involved in non-syndromic hypodontia, while genes such as Shh, Pitx2, Irf6, and p63 are considered to participate in syndromic genetic disorders, which include tooth agenesis. In dentistry, artificial tooth implants represent a common solution to tooth loss problems; however, molecular dentistry offers promising solutions for the future. In this paper, the genetic and molecular bases of non-syndromic and syndromic hypodontia are reviewed, and the advantages and disadvantages of tissue engineering in the clinical treatment of tooth agenesis are discussed.     

牙组织工程干细胞的研究进展

牙组织工程是一项以牙发育原理为基础,将组织工程学的原理和技术应用于牙体损伤修复和牙再生的研究技术.即从成牙组织中分离和培养一定数量的具有生长和分化能力的干细胞,通过适宜的微环境在体内或体外构建有功能的组织工程化牙齿.其关键之处是选择合适的干细胞.笔者下面就牙组织工程干细胞的研究进展作一综述.     

大鼠完整牙胚肾被膜下种植实验研究

目的：评价肾被膜作为组织工程牙根和牙周组织的种植环境。方法：分离出生后6 d SD大鼠下颌第一磨牙完整牙胚,种植于成年SD大鼠肾被膜下,4周后收获种植牙胚,组织学观察种植牙胚的牙根和牙周组织发育情况。结果：20个种植牙胚中,4个种植牙胚有牙根和牙周组织生成,剩余种植牙胚仅见牙本质继续发育。结论：肾被膜是组织工程牙根和牙周组织的适宜种植环境。     

组织工程化牙齿研究展望

本文通过综述牙齿发育学家、牙髓生物学家的态度，对组织工程化牙齿研究的前景进行了展望；并且对组织工程化牙齿研究现状以及发育学和干细胞生物学与组织工程化牙齿研究之间的联系进行了回顾。     

Tooth development: 2. Regenerating teeth in the laboratory

Tooth loss can occur for a number of reasons and a variety of prosthetic tooth replacement solutions are available to the dental practitioner. This article discusses current approaches in the use of tissue engineering to replace teeth or repair dental tissues. These strategies will depend upon the manipulation of stem cells in the laboratory and, whilst much progress has recently been made, it is likely that successful human tooth regeneration is still some years ahead.     

引导牙周组织再生在伴牙槽骨缺损牙再植术中应用的回顾性研究

目的 :回顾分析配合引导性组织再生术 (guidedtissueregeneration ,GTR)治疗对伴牙槽骨缺损的脱位再植牙的临床疗效的影响 ,为引导牙周组织再生的进一步研究提供经验。方法 :收集 1996年～ 2 0 0 3年间伴牙槽骨缺损、再植术中配合了GTR术治疗的完整病历资料 ,对其临床治疗情况及近远期疗效作回顾性研究分析。结果 :共收集到 2 3份符合条件的病历 (6 4颗再植牙 ) ,疗效分析结果表明 ,患牙术后 12个月探诊深度均显著减少 ,附着水平均显著获得 ;无论脱位时间长短 ,术后牙松动、牙根吸收和失牙的发生率均较高。伤后 6h内就诊脱位牙直接再植后 ,牙髓坏死率 77.5 % ,牙根吸收和失牙率与伤后就诊超过 6h组有显著性差异 (P <0 .0 1)。结论 :伤后就诊时间影响再植牙治疗效果 ,配合单纯GTR治疗 ,伴牙槽骨缺损的脱位再植牙的远期疗效仍然较差 ,利用GTR技术促进牙周组织再生特别是促进牙周缺损的再生需要进一步的基础与临床研究。     

牙齿再生——梦想与现实

牙齿及牙列缺失在临床上很常见，目前的修复方法均为非生物性的，尚不能满足人们的要求。实现真牙再生一直是一个梦想。牙齿再生分为全牙再生和部分牙齿再生，前者目前尚存在相当大的困难，但后者已有可喜进展，已在小鼠及大型动物小型猪上成功再生出生物牙根，有望成为全牙再生成功前良好的过渡。研究表明骨髓中部分细胞在一定条件下可以直接分化为成釉上皮样细胞及成牙本质细胞，有望成为牙齿再生的间充质来源的种子细胞。     

微球在牙体组织再生领域应用的研究进展

随着组织工程技术和再生学科的发展,失去的牙体组织再生成为可能.微球作为组织工程中常用的载体形式,适用于小且形状不规则的牙体组织再生,同时还可利用微球的靶向性和缓释控释来运输各种生长因子、药物等到达指定区域.本文就微球在牙体组织再生领域应用的研究现状进行综述.