What and where are the stem cells for Dentistry?

Disinfection of root canals followed by the replacement of the infected or inflamed pulp tissues by inert materials is the foundation for treating irreversible damaged dental pulps. The management of pathological conditions of the periodontium is mainly based solely upon infection control via the reestablishment of oral hygiene, scaling and root planing to control inflammation which stops progressive bone loss. As one may see, the clinical management of endodontic and periodontal diseases has not changed drastically despite the development of new materials, techniques and medicaments. Tissue engineering is a multi-disciplinary field focused on the development of materials, techniques and strategies to improve or replace damaged or lost biological functions and tissues. As the tissue engineering field progresses, “scaffolds”, “suggest pathways” and “stem cells” abandoned their role as technical words exclusively used by scientists and slowly assume a part in the language of students, educators, clinicians and patients. However the unfamiliarity with some of the concepts can lead to misinterpretations of the current status and overexcitement about future applications of stem cells for dental-related tissue regeneration. This paper will present a panorama and the future challenges on the path to use of stem cells for endodontic and periodontal tissue regeneration.     

Combined treatment of a large periodontal defect using GTR and DFDBA

The regeneration of periodontal structures lost to inflammatory disease is an elusive yet attainable goal of periodontal therapy. This article reports the successful treatment of a large periodontal defect using a combination of demineralized freeze-dried bone allograft (DFDBA) and guided tissue regeneration (GTR). The case presents endodontic and mucogingival complications in the combined GTR osseous graft technique. The combined techniques used in this 27-year-old patient achieved a reduction in probing depth, radiographic evidence of bone fill, and a reduction in clinical mobility.     

Rationale for the application of the GTR principle using a barrier membrane in endodontic surgery: a proposal of classification and literature review

Periradicular surgery has become an established treatment option in endodontic surgery. The major objective of this surgery is to obtain periradicular tissue regeneration, including the formation of a new attachment apparatus, by exclusion of any potentially noxious agent within the physical confines of the affected root. However, in a substantial number of cases, the endodontic lesion has a concomitant marginal periodontal lesion that may complicate the healing success. In periodontology, the guided tissue regeneration (GTR) principle using a barrier membrane has been extensively studied and successfully used, and thus may become an adjunct in endodontic surgery. This article presents a classification system of endodontic and periodontal lesions with respect to the application of the membrane technique and reviews the pertinent literature based upon this classification system.     

Periodontal materials

Periodontics is more associated with debridement of periodontal pockets and not generally thought of as using dental materials in the treatment of patients. However, the last 30 years have seen the development of materials used in regeneration of the periodontal tissues following periodontal disease, guided tissue regeneration, and the use of these materials in bone regeneration more recently, guided bone regeneration. The materials used include bone grafts and membranes, but also growth factors and cells-based therapies. This review provides an overview of the materials currently used and looks at contemporary research with a view to what may be used in the future. It also looks at the clinical effectiveness of these regenerative therapies with an emphasis on what is available in Australia.     

Surgical endodontic management of an invasive cervical resorption class 4 with mineral trioxide aggregate: a 6-year follow-up

Invasive cervical resorption is a type of external resorption rarely seen as an adverse effect after a guided tissue regeneration procedure for a periodontal condition. This case report summarizes the surgical endodontic management of an invasive cervical resorption class 4 (Heithersay) with mineral trioxide aggregate, in a mandibular incisor of a 67-year-old man. A 6-year clinical follow-up with radiovisiography and cone-beam computerized tomography revealed complete healing. A surgical endodontic management could promote healing and survival of a tooth with advanced root resorption due to a periodontal condition.     

Mineral trioxide aggregate: a new material for endodontics.

BACKGROUND: Mineral trioxide aggregate, or MTA, is a new material developed for endodontics that appears to be a significant improvement over other materials for procedures in bone. It is the first restorative material that consistently allows for the overgrowth of cementum, and it may facilitate the regeneration of the periodontal ligament. CASE DESCRIPTION: The authors present five cases in which MTA was used to manage clinical problems. These included vertical root fracture, apexification, perforation repair and repair of a resorptive defect. In each case, MTA allowed bone healing and elimination of clinical symptoms. CLINICAL IMPLICATIONS: Materials such as zinc oxide-eugenol cement and resin composite have been used in the past to repair root defects, but their use resulted in the formation of fibrous connective tissue adjacent to the bone. Because it allows the overgrowth of cementum and periodontal ligament, MTA may be an ideal material for certain endodontic procedures.     

Soft tissue management in endodontic surgery

Modern endodontic surgery involves both root-end preparation and proper sealing of all apical portals of exit. Both components are requirements for mechanical and biological success, but the management of soft tissues becomes increasingly important for an esthetically successful treatment. A healthy appearance of soft tissues plays an important role in the esthetic outcome of periradicular surgery. This is true considering maintenance of attachment levels and regarding the amount of possible recession after surgical procedures. Complete, recession-free and predictable healing of gingival tissue is one important goal of endodontic surgical treatment. A critical review of currently used techniques based on clinical and scientific data reveals great potential for improvements. Possible reasons for scar formation and recession specifically in healthy periodontal conditions requiring surgical endodontic intervention are highlighted. Based on anatomical considerations various incision types are evaluated and recommendations made. Clear understanding of wound closure and tissue-healing patterns call for the use of atraumatic procedures, nonirritating suture materials and adequate suturing techniques. This article gives an overview and guidance for integrating current and new successful flap designs and wound closure methods. The methods described have the intention of maintaining the attachment level and avoiding postoperative recession after surgical endodontic therapy.     

The influence of endodontic treatment upon periodontal wound healing

Abstract The interrelationship between periodontal and endodontic disease has aroused much speculation, confusion, and controversy. Pulpal and periodontal problems are responsible for more than 50% of tooth mortality today. Diagnosis is often difficult since these diseases have been studied primarily as separate entities. The toxic substances of the pulp may initiate periodontal defects through canal ramifications and patent dentinal tubules, thus impairing wound healing in regenerative procedures. Although no studies exist addressing the direct effect of pulpal infection on the outcome of guided tissue regeneration (GTR) procedures, several studies do indicate that pulpal status may play a significant role toward the end results of GTR. This review article discusses the potential influence of endodontic treatment on the long-term outcomes of GTR. Potential pathways between the pulp and periodontal ligament, which may be responsible for the failure of the regeneration of new periodontal attachment apparatus, are explored. Examination and review of the clinical and research findings in the literature relating to perio-endo lesions are made to demonstrate that a negative influence may exist between GTR outcomes and the status of the pulp.     

Experimental and clinical studies on regenerative periodontal therapy

The recognition of a periodontal therapy as a regenerative procedure requires the demonstration of new cementum, periodontal ligament, and bone coronal to the base of the defect. A diversity of regenerative strategies has been evaluated, including root surface conditioning, bone grafts and bone substitute materials, guided tissue regeneration, enamel matrix proteins, growth/differentiation factors, combined therapies and, more recently, tissue‐engineering approaches. The aim of this chapter of Periodontology 2000 is to review the research carried out in Latin America in the field of periodontal regeneration, focusing mainly on studies using preclinical models (animal models) and randomized controlled clinical trials. This review may help clinicians and researchers to evaluate the current status of the therapies available and to discuss the challenges that must be faced in order to achieve predictable periodontal regeneration in clinical practice.     

Periodontal tissue engineering and regeneration: Consensus Report of the Sixth European Workshop on Periodontology

Aim: To review the scientific preclinical background and clinical studies of current methods of periodontal regeneration in the treatment of infrabony defects and soft tissue deficiencies
Method: Five commissioned review papers including two systematic reviews were scrutinized by a group of experts in order to derive consensus conclusions, clinical relevance/implications and to propose future research requirements.
Results: The following five papers were assessed:
  1. Biological mediators and periodontal regeneration: a review of enamel matrix proteins at the cellular and molecular levels.
  2. Regeneration of periodontal tissues: combination of barrier membranes and grafting materials – Biological foundation and preclinical evidence.
  3. Clinical outcomes with bioactive agents alone or in combination with grafting or GTR
  4. Treatment of gingival recession with coronally advanced flap procedures. A systematic review.
  5. Soft tissue management at implant sites     

Periodontal regeneration techniques for treatment of periodontal diseases

The ultimate goal of periodontal therapy is the regeneration of structures lost to disease. Conventional surgical approaches such as open-flap debridement offer only limited regeneration potential.Currently, surgical procedures for predictable regeneration of periodontal tissues are being developed, analyzed, and employed in clinical practice. This article addresses current trends in periodontal regeneration. Various materials/agents such as bone replacement grafts, barrier membranes, and biologic modifiers currently used for the regeneration of periodontal infrabony and furcation defects are discussed.     

Tissue engineered periodontal products

Attainment of periodontal regeneration is a significant clinical goal in the management of advanced periodontal defects arising from periodontitis. Over the past 30 years numerous techniques and materials have been introduced and evaluated clinically and have included guided tissue regeneration, bone grafting materials, growth and other biological factors and gene therapy. With the exception of gene therapy, all have undergone evaluation in humans. All of the products have shown efficacy in promoting periodontal regeneration in animal models but the results in humans remain variable and equivocal concerning attaining complete biological regeneration of damaged periodontal structures. In the early 2000s, the concept of tissue engineering was proposed as a new paradigm for periodontal regeneration based on molecular and cell biology. At this time, tissue engineering was a new and emerging field. Now, 14 years later we revisit the concept of tissue engineering for the periodontium and assess how far we have come, where we are currently situated and what needs to be done in the future to make this concept a reality. In this review, we cover some of the precursor products, which led to our current position in periodontal tissue engineering. The basic concepts of tissue engineering with special emphasis on periodontal tissue engineering products is discussed including the use of mesenchymal stem cells in bioscaffolds and the emerging field of cell sheet technology. Finally, we look into the future to consider what CAD/CAM technology and nanotechnology will have to offer.     

Guided tissue regeneration in periodontal therapy.

In teeth where continued function requires additional periodontal support, optimal treatment requires not only controlling periodontal infection, but also regeneration of periodontal support lost to periodontal disease. Today, guided tissue regeneration (GTR) is a technique with significant clinical and histologic documentation of periodontal regeneration. This paper will address GTR barriers and clinical indications for using these materials to successfully regenerate the periodontium.     

An overview of periodontal regenerative procedures for the general dental practitioner

The complete regeneration of the periodontal tissues following periodontal disease remains an unmet challenge, and has presented clinicians with a remarkably difficult clinical challenge to solve given the extensive research in this area and our current understanding of the biology of the periodontal tissues. In particular as clinicians we look for treatments that will improve the predictability of the procedure, improve the magnitude of the effect of treatment, and perhaps most importantly in the long term would extend the indications for treatment beyond the need for single enclosed bony defects to allow for suprabony regeneration, preferably with beneficial effects on the gingival soft tissues. A rapid development in both innovative methods and products for the correction of periodontal deficiencies have been reported during the last three decades. For example, guided tissue regeneration with or without the use of bone supplements has been a well-proven treatment modality for the reconstruction of bony defects prior to the tissue engineering era. Active biomaterials have been subsequently introduced to the periodontal community with supporting dental literature suggesting that certain factors should be taken into consideration when undertaking periodontal regenerative procedures. These factors as well as a number of other translational research issues will need to be addressed, and ultimately it is vital that we do not extrapolate results from pre-clinical and animal studies without conducting extensive randomized clinical trials to substantiate outcomes from these procedures. Whatever the outcomes, the pursuit of regeneration of the periodontal tissues remains a goal worth pursuing for our patients. The aim of the review, therefore is to update clinicians on the recent advances in both materials and techniques in periodontal regenerative procedures and to highlight the importance of both patient factors and the technical aspects of regenerative procedures.     

Biomaterials for promoting periodontal regeneration in human intrabony defects: a systematic review

Intrabony periodontal defects are a frequent complication of periodontitis and, if left untreated, may negatively affect long‐term tooth prognosis. The optimal outcome of treatment in intrabony defects is considered to be the absence of bleeding on probing, the presence of shallow pockets associated with periodontal regeneration (i.e. formation of new root cementum with functionally orientated inserting periodontal ligament fibers connected to new alveolar bone) and no soft‐tissue recession. A plethora of different surgical techniques, often including implantation of various types of bone graft and/or bone substitutes, root surface demineralization, guided tissue regeneration, growth and differentiation factors, enamel matrix proteins or various combinations thereof, have been employed to achieve periodontal regeneration. Despite positive observations in animal models and successful outcomes reported for many of the available regenerative techniques and materials in patients, including histologic reports, robust information on the degree to which reported clinical improvements reflect true periodontal regeneration does not exist. Thus, the aim of this review was to summarize, in a systematic manner, the available histologic evidence on the effect of reconstructive periodontal surgery using various types of biomaterials to enhance periodontal wound healing/regeneration in human intrabony defects. In addition, the inherent problems associated with performing human histologic studies and in interpreting the results, as well as certain ethical considerations, are discussed. The results of the present systematic review indicate that periodontal regeneration in human intrabony defects can be achieved to a variable extent using a range of methods and materials. Periodontal regeneration has been observed following the use of a variety of bone grafts and substitutes, guided tissue regeneration, biological factors and combinations thereof. Combination approaches appear to provide the best outcomes, whilst implantation of alloplastic material alone demonstrated limited, to no, periodontal regeneration.     

Overview: A New Function of Amelogenin: — From Bench to Clinics,and Clinics to Bench—

Periodontal disease is a major concern in dentistry because it causes the loss of periodontal tissue, resulting in tooth loss that induces both aesthetic and functional problems for patients. Various methods have been used to facilitate the regeneration of lost or diseased periodontal tissue. Guide tissue regeneration (GTR) is a widely accepted procedure to promote re-growth of the periodontium ; however, this is often difficult to achieve since periodontal tissue is composed of various types of cells and elements. Treating the site with agents that promote tissue regeneration would be beneficial. Emdogain® (enamel-matrix derivative ; EMD ; Straumann AG, Basel, Switzerland) is a well-known product that stimulates the formation of new bone, cementum and attachment fibers in the area of periodontal tissue loss. It contains enamelmatrix proteins, including mainly amelogenins derived from the developing teeth of the pig. The purpose of this review was to critically evaluate the current state of knowledge of the potential role of amelogenin in the field of periodontal tissue regeneration. This review also provides information regarding the structure and novel functions of amelogenin.     

Periosteal grafts as barriers in periradicular surgery: report of two cases

AIM: To describe the usefulness of periosteal grafts as barriers for bone regeneration in periradicular surgery when advanced periodontal breakdown occurs. SUMMARY: The treatment of advanced periodontal breakdown as a result of an associated endodontic lesion constitutes a multifaceted challenge to the clinician. If the source of the irritation cannot be removed by orthograde endodontic treatment, nonsurgical and surgical endodontic/periodontal intervention may be required. Two cases with suppurative chronic apical periodontitis with apicomarginal communication are described. Clinical and radiological evaluations were completed immediately prior to surgery, a week later and every 2 months after surgery for 10 months. Both patients were treated using split-thickness flaps and lateral displacement of the periosteum prior to suturing, in order to close the communication between the oral and the periapical surroundings. A remission of the clinical signs and symptoms, and successful healing in the short-term were achieved in these cases. KEY LEARNING POINTS: Periapical and periodontal lesions are closely related through pathways of communication. Disruption of the cortical plate and the presence of dentoalveolar sinus tracts can have a deleterious effect on the regeneration process after periradicular surgery. The adoption of supplementary periodontal surgical techniques may help to solve some of the difficulties in the healing process in periradicular surgery. Periosteal grafts have been shown to have the potential to stimulate bone formation when used as a graft material.     

Multidisciplinary approach to the rehabilitation of a crown fracture with glass-fibre-reinforced composite: a case report

Traumatic tooth injuries are common in children. When permanent teeth are involved, it can be a challenge to save these teeth. This clinical case study describes the multidisciplinary treatment of a complex crown fracture and luxation of a right maxillary incisor along with esthetic management. After periodontal surgery including guided bone regeneration and endodontic treatment, we used a glass-fibre-reinforced composite post to increase retention and distribute stress along the root. The restoration was completed using composite in an incremental technique. During follow-up appointments, clinical and radiographic examinations revealed no root canal or periodontal problems, suggesting the efficacy of the treatment in retaining the fractured tooth. Periodontal surgery with endodontic treatment is an alternative treatment for severe trauma in permanent teeth.     

Suturing for optimal soft tissue management

For optimal postsurgical wound healing, non-tension primary wound closure of various soft tissue flaps must be established. Surgical procedures that require clinical flap manipulation (such as those used with traditional periodontal therapy, periodontal plastic cosmetic surgery, hard and soft tissue regeneration, and the excision of pathologic tissue) also require excellent execution and a thorough understanding of the various techniques of surgery, suturing, and the materials currently available for the desired clinical results. This article discusses the rationale behind specific suturing techniques and suture materials to aid the clinician with optimal wound closure.     

组织工程技术应用于牙周膜再生研究进展

组织工程技术是一项利用生物替代材料修复受损组织的技术,广泛应用于组织再生,也为口腔牙周膜再生提供了新的方法。文章就近年来牙周膜再生治疗中关于支架材料、生长因子、种子细胞等组织工程技术的研究及应用进展做一综述。