Clinical classification of bone defects concerning the placement of dental implants

The goal of this classification of bone defects related to dental implant placement is to help clinicians accurately discuss proposed treatment regimens and organize treatment for clinical correction. A further goal of this effort to categorize bone defects requiring bone augmentation for implant placement is to standardize terminology to allow for more accurate dental communication. The five most encountered categories of bony defects are described.     

Localized maxillary ridge augmentation with a block allograft for dental implant placement: case reports

Autogenous block bone grafts have been highly successful in treating human periodontal defects, restoring esthetics, and developing adequate bone volume for dental implant placement. Limitations in available donor bone, the need for an added surgical procedure, and other potential complications have made the use of allogenic bone graft materials an important alternative. One patient described in this report presented with fractured root syndrome of the right maxillary incisor with severe resorption of the buccal plate. After atraumatic tooth extraction, a staged treatment approach involving localized ridge augmentation with an allogenic iliac bone block material and dental implant placement was used. The host bone completely incorporated the graft with only minor resorption, which enabled the implant to be placed. The allogenic bone block material used in this study was an effective alternative to harvesting and grafting autogenous bone for implant site development. The cases presented in this article clinically demonstrate the efficacy of using a block allograft in generating effective new bone fill for dental implant placement.     

"Sandwich" bone augmentation technique: rationale and report of pilot cases

The aim of this article is to present a new technique for augmentation of deficient alveolar ridges and/or correction of osseous defects around dental implants. Current knowledge regarding bone augmentation for treatment of osseous defects prior to and in combination with dental implant placement is critically appraised. The "sandwich" bone augmentation technique is demonstrated step by step. Five pilot cases with implant dehiscence defects averaging 10.5 mm were treated with the technique. At 6 months, the sites were uncovered, and complete defect fill was noted in all cases. Results from this pilot case study indicated that the sandwich bone augmentation technique appears to enhance the outcomes of bone augmentation by using the positive properties of each applied material (autograft, DFDBA, hydroxyapatite, and collagen membrane). Future clinical trials for comparison of this approach with other bone augmentation techniques and histologic evaluation of the outcomes are needed to validate these findings.     

A concept for the treatment of various dental bone defects

Untreated dental bone defects usually lead to resorption of alveolar bone. Filling these defects with bone substitute material prevents resorption of bone, preserves the alveolar ridge, and provides sufficient bone for immediate or subsequent implant placement. A variety of bone substitutes is available. They differ in origin, consistency, particle size, porosity, and resorption characteristics. We have treated almost 1000 bony defect sites in 267 patients with the bone regeneration material Cerasorb. Being resorbed simultaneously with the formation of new bone, it is completely replaced by the patient's own vital bone within 6 to 12 months. The representative cases described in this paper demonstrate the successful use of the pure-phase beta-tricalcium phosphate ceramic in the treatment of all dental bone defects.     

Reconstruction of maxillary alveolar defects with mandibular symphysis grafts for dental implants: a preliminary procedural report.

Partially edentulous patients with alveolar defects contraindicating implant placement were treated with bone grafts obtained from the mandibular symphysis. Complications encountered were minor and uneventful. Evaluation 4 months after surgery revealed minimal graft resorption, thus implant placement was possible in all potential sites. Advantages of the symphysis graft include easy access, availability of greater quantities of bone over other intraoral donor sites, low morbidity, no hospitalization, minimal discomfort, no alteration in ambulation, and no cutaneous scar. Compared with other bone regenerative methods for implant placement, a superior quality of bone was found and a shorter healing period is required. Results of this preliminary clinical investigation demonstrate that chin grafts offer a viable alternative for reconstruction of alveolar defects prior to dental implant placement.     

Placement of endosseous implants into tooth extraction sites

This study reports 4-year experiences with placement of hydroxylapatite-coated dental implants into extraction sites immediately after tooth extraction. Small defects present after implant placement were treated with dense, nonresorbable hydroxylapatite. Larger defects present after implant placement were treated with demineralized bone. Indications and contraindications for placement, as well as surgical techniques, are discussed.     

Preservation of ridge dimensions following grafting with coral granules of 48 post-traumatic and post-extraction dento-alveolar defects

Abstract – This prospective clinical analysis reports on the use of coral granules in alveolar ridge preservation procedures in a population of young, growing patients. The sample consisted of 21 patients, 12 females and 9 males, with a mean age of 13.6 years. These 21 patients had 48 dento‐alveolar defects suitable for augmentation with coral granules, and were followed clinically and radiographically for 3–7 years after augmentation. There were two areas of augmentation: 17 defects in the anterior maxilla resulted from traumatic tooth loss, and 31 defects in the posterior maxilla and mandible resulted from the extraction of ankylosed retained primary molars with no permanent succedaneous teeth. Between 1–2 ml of coral granules were implanted into the alveolar bone defects left by the extraction of teeth in both the areas. This was in order to preserve the remaining edentulous ridge from further alveolar ridge resorption. The goal of the procedure was to preserve the alveolus so that in the future, a dental implant could be placed to replace the missing tooth, after jaw growth had stopped, without the need for a bone graft. The coral granules appeared to be totally replaced by the host bone on follow‐up clinical and radiographic examinations. The two areas of the jaws behaved quite differently. In the anterior maxilla, where tooth loss was secondary to trauma, the coral granules restored the alveolar ridges temporarily. However, over the years of follow‐up in this study, the coral granules failed to provide sufficient bone to support the placement of a dental implant without using a bone graft in 14 of the 17 defects or 82.4% of sites. In the posterior maxilla and mandible, where tooth loss was due to the elective removal of ankylosed primary molars, 29 of the 31 defects or 93.5% of sites were successful as they were able to support the placement of an osseo‐integrated dental implant without the use of a bone graft. The alveolar sparing technique was more successful in maintaining an alveolar ridge sufficient for the placement of a dental implant without bone grafting in the posterior maxilla and mandible, where tooth loss was secondary to the elective removal of ankylosed deciduous molars than in the anterior maxilla, where tooth loss was secondary to trauma. Coral granules seem to be more suitable in the posterior maxilla and mandible where there were ankylosed deciduous teeth and congenitally absent permanent teeth than in the traumatized anterior maxilla. In successful sites, coral granules can spare the alveolus from residual ridge atrophy or resorption, obviating the need for a bone graft. This reduces patient morbidity, as a second surgical donor site is avoided because bone graft harvesting is made unnecessary.     

Bone augmentation techniques

BACKGROUND: The advent of osseointegration and advances in biomaterials and techniques have contributed to increased application of dental implants in the restoration of partial and completely edentulous patients. Often, in these patients, soft and hard tissue defects result from a variety of causes, such as infection, trauma, and tooth loss. These create an anatomically less favorable foundation for ideal implant placement. For prosthetic-driven dental implant therapy, reconstruction of the alveolar bone through a variety of regenerative surgical procedures has become predictable; it may be necessary prior to implant placement or simultaneously at the time of implant surgery to provide a restoration with a good long-term prognosis. Regenerative procedures are used for socket preservation, sinus augmentation, and horizontal and vertical ridge augmentation. METHODS: A broad overview of the published findings in the English literature related to various bone augmentation techniques is outlined. A comprehensive computer-based search was performed using various databases that include Medline and PubMed. A total of 267 papers were considered, with non-peer-reviewed articles eliminated as much as possible. RESULTS: The techniques for reconstruction of bony defects that are reviewed in this paper include the use of particulate bone grafts and bone graft substitutes, barrier membranes for guided bone regeneration, autogenous and allogenic block grafts, and the application of distraction osteogenesis. CONCLUSIONS: Many different techniques exist for effective bone augmentation. The approach is largely dependent on the extent of the defect and specific procedures to be performed for the implant reconstruction. It is most appropriate to use an evidenced-based approach when a treatment plan is being developed for bone augmentation cases.     

Diagnosis and treatment of extraction sockets in preparation for implant placement: report of three cases

This article addresses diagnostic parameters that should be assessed in the treatment of extraction sockets with dental implant placement by presenting three case reports that emphasize the relevance of the amount of remaining bone walls. Diagnosis was based on the analysis of clinical and radiographic parameters (e.g.: bone defect morphology, remaining bone volume, presence of infections on the receptor site). Case 1 presents a 5-wall defect in the maxillary right central incisor region with severe root resorption, which was treated with immediate implant placement. Cases 2 and 3 present, respectively, two- and three-wall bone defects that did not have indication for immediate implants. These cases were first submitted to a guided bone regeneration (GBR) procedure with bone graft biomaterial and membrane barriers, and the implants were installed in a second surgical procedure. The analysis of the preoperative periodontal condition of the adjacent teeth and bone defect morphology is extremely important because these factors determine the choice between immediate implant or GBR treatment followed by implant installation in a subsequent intervention.     

Randomized study evaluating recombinant human bone morphogenetic protein-2 for extraction socket augmentation

BACKGROUND: Conventional dentoalveolar osseous reconstruction often involves the use of grafting materials with or without barrier membranes. The purpose of this study was to evaluate the efficacy of bone induction for the placement of dental implants by two concentrations of recombinant human bone morphogenetic protein-2 (rhBMP-2) delivered on a bioabsorbable collagen sponge (ACS) compared to placebo (ACS alone) and no treatment in a human buccal wall defect model following tooth extraction. METHODS: Eighty patients requiring local alveolar ridge augmentation for buccal wall defects (> or =50% buccal bone loss of the extraction socket) of the maxillary teeth (bicuspids forward) immediately following tooth extraction were enrolled. Two sequential cohorts of 40 patients each were randomized in a double-masked manner to receive 0.75 mg/ml or 1.50 mg/ml rhBMP-2/ACS, placebo (ACS alone), or no treatment in a 2:1:1 ratio. Efficacy was assessed by evaluating the amount of bone induction, the adequacy of the alveolar bone volume to support an endosseous dental implant, and the need for a secondary augmentation. RESULTS: Assessment of the alveolar bone indicated that patients treated with 1.50 mg/ml rhBMP-2/ACS had significantly greater bone augmentation compared to controls (P < or =0.05). The adequacy of bone for the placement of a dental implant was approximately twice as great in the rhBMP-2/ACS groups compared to no treatment or placebo. In addition, bone density and histology revealed no differences between newly induced and native bone. CONCLUSION: The data from this randomized, masked, placebo-controlled multicenter clinical study demonstrated that the novel combination of rhBMP-2 and a commonly utilized collagen sponge had a striking effect on de novo osseous formation for the placement of dental implants.     

Dental implant therapy in the treatment of an oroantral communication after exodontia

A new technique in which a dental implant was the ultimate therapy for the treatment of an oroantral communication (OAC) that was created subsequent to the extraction of a maxillary first molar is described. A search of the English-speaking literature has not revealed implant therapy as part of documented modalities for the treatment of an OAC created following dental extraction. The OAC was closed by a sandwich technique that uses two resorbable membrane materials (Bio-Gide, Osteohealth, Shirley, NY) that surround a bone substitute (Bio-Oss, Osteohealth). This procedure, together with additional onlay grafting with the same bone substitute, was used also to regenerate subantral bone to enable the subsequent placement of an endosseous implant after 12 months. An 8-month postoperative radiograph showed creation of a new maxillary sinus bony floor and subantral bone of good quality, and height that can permit the placement of an endosseous dental implant.     

The use of autogenous block graft for augmentation of the atrophic alveolar ridge

The use of osseointegrated implants has become a standard treatment option in modern dental rehabilitation. Adequate bone quantity and quality is a prerequisite for good esthetic and biomechanical result. Alveolar ridge defects can be the result of trauma, periodontal diseases or other pathologic conditions. In these cases, alveolar ridge augmentation is needed if endosseous implants are to be used. While xenografts, alloplastic bone grafts and allografts have been proposed for alveolar ridge augmentation, the use of autogenous bone grafts represents the "gold standard" for bone augmentation procedures. Either intraoral or extraoral sites may be considered for donor sites. Although the iliac crest is the most common donor site in maxillofacial reconstruction, the mandibular symphysis or ramus offer important advantages like avoidance of general anesthesia, convenience due to the proximity between the donor site and the augmentation site and avoidance of cutaneous scar. Bone harvested from intraoral donor site is less associated with resorption when compared with iliac bone because membranous grafts revascularize more quickly than endocondral bone grafts. The main disadvantage of the intraoral donor sites is the limited amount of available bone. Alveolar ridge augmentation using autologous bone block, can be done during implant placement or staged with implant placement, after bone graft healing. In the staged technique, a better implant positioning and the use of wide diameter implants are possible. The overall implant success is higher in the staged technique. Alveolar ridge augmentation using autogenous block graft is a predictable way of treatment, for the atrophic alveolar ridge before implant placement.     

Vertical mandibular alveolar bone distraction and dental implant placement: a case report

Extensive bone defects complicate the adequate placement of dental implants and the required angulation. In such cases, alveolar-ridge augmentation techniques such as guided bone regeneration, particulate or block grafting, and alveolar bone distraction are needed. The present study describes a case in which a large vertical bone defect in the anterior mandibular zone was corrected via vertical alveolar bone distraction. Six dental implants were posteriorly placed for implant-supported restoration of the mandible, with early implant loading. The clinical and radiologic control showed good implant and soft tissue conditions 12 months later.     

Reconstruction techniques preparing jaws for fixed dentures placement

Dental implantation is a widespread method of dental arch reconstruction. Alveolar bone quantity in implantation area is crucial for proper implant placement. The paper presents author's experience in alveolar bone reconstruction with mandibular autografts, bone height reconstruction with parietal partial thickness grafts, as well as jaw defects reconstruction with microvascular flaps with subsequent implantation.     

Simple preservation of a maxillary extraction socket using beta-tricalcium phosphate with type I collagen: preliminary clinical and histomorphometric observations

Alveolar atrophy following tooth extraction remains a challenge for future dental implant placement. Immediate implant placement and postextraction alveolar preservation are 2 methods that are used to prevent significant postextraction bone loss. In this article, we report the management of a maxillary tooth extraction socket using an alveolar preservation technique involving placement of a cone of beta-tricalcium phosphate (beta -TCP) combined with type I collagen without the use of barrier membranes or flap surgery. Clinical examination revealed solid new bone formation 9 months after the procedure. At the time of implant placement, histomorphometric analysis of the biopsied bone showed that it contained 62.6% mineralized bone, 21.1% bone marrow and 16.3% residual beta -TCP graft. The healed bone was able to support subsequent dental implant placement and loading.     

Endosseous implant placement immediately following dental extraction and alveoloplasty: preliminary report with 6-year follow-up.

The philosophy of retaining natural teeth as long as possible for the preservation of alveolar bone has been a fundamental concept of dental treatment. With the introduction of predictable osseointegrated implant-supported prostheses, placement of an implant immediately after dental extraction can be considered. This paper discusses the technique of implant placement immediately following dental extraction. Clinical experience including 61 patients with follow-up of 1 to 6 years is reported.     

血浆基质在口腔种植水平骨增量中的应用

牙齿缺失伴随着牙槽骨吸收或缺损,导致骨量和软组织量不足。种植治疗除恢复缺失牙的咀嚼功能外,还需恢复牙弓的轮廓和外形,引导骨再生术是骨增量的常用手段。异种颗粒状骨替代材料因其降解时间长、免疫反应低等优点,在临床水平骨增量领域应用广泛,但存在操作不便、成骨活性低等问题。血浆基质能有效提高口腔组织再生效果、减少术后并发症的出现,在口腔组织再生中的应用逐渐增多。本文首先介绍了血浆基质在水平骨增量中的主要应用形式(固态血浆基质膜、血浆基质骨块),并根据临床常用的骨增量决策方案,即是否能够在理想位置植入种植体以及植入后是否存在骨开裂对水平骨缺损进行重新分类,其中Ⅰ类水平骨缺损为缺牙位点骨量可供植入理想尺寸的种植体,且种植体周围无骨开裂,但牙槽骨轮廓比非缺牙区凹陷的情况;Ⅱ类水平骨缺损为缺牙位点骨量根据未来修复体位置确定的种植位点植入理想尺寸种植体后,种植体三侧均有骨,但颊侧骨壁存在骨开裂(骨开裂长度小于种植体长度的50%)的情况;Ⅲ类水平骨缺损为缺牙位点骨量不足以在理想位置植入理想尺寸的种植体,需要先行植骨恢复骨量以利于种植体植入的情况。本文随后对血浆基质在不同水平骨缺损类型中的应用方法进行阐述:...     

Use of Diagnostic and Surgical Stent: A Simplified Approach for Implant Placement

Dental implantology has emerged as a practical alternative to traditional prosthodontics. Since the beginning, placement of implant in the bone to achieve a prosthetic solution that fulfils biologic, aesthetic and biomechanical requirements has been a challenge. In the past, implant site and inclination were dictated by residual bone quality. The desire for predictable prosthesis led to the development of prosthetically guided implantology. This concept establishes the correct implant position during the diagnostic stage according to planned definitive restoration. In prosthetically guided implantology where ideal placement of implant is determined by the definitive restoration, use of radiographic and surgical stent in conjunction with dental CT scan can play an important role. A stent is an appliance used for radiographic evaluation during treatment planning for implant placement and during surgical procedures to locate optimal implant placement site. The stent with dental CT scan enables the dental team to identify specific sites of prospective implant surgery and hence determines the optimal position and angulation of implant relative to occlusal load. Aided by stent the surgeon can avoid undesirable implant site preparation and minimize unnecessary osteotomy, resulting in favorable design of prosthesis, reduced surgical trauma, reduced surgical time and increased patient comfort. This case report is an insight into the method of fabrication of simple and cost effective stent for implant placement and its advantages over the other techniques of stent fabrication.     

Localized ridge augmentation with allogenic block grafts prior to implant placement: case reports and histologic evaluations

The placement of dental implants is based on the amount of alveolar bone present in the edentulous site to be reconstructed. Insufficient alveolar contours may require bone grafting procedures to restore an adequate bone volume before implant placement. Larger osseous defects often require block grafts harvested from the symphysis or the ramus buccal shelf region. These provide adequate donor sites to harvest a graft sufficient to restore a significant defect in the osseous structures planned for implant placements. Autogenous block grafts have been well established to reconstruct these types of defects prior to implant placement procedures. However, surgical complications associated with the unfavorable anatomical structures and the necessity of large donor sites (e.g., symphysis and ramus buccal shelf) have led to the use of allogenic grafting materials. Recent developments in allogenic grafting materials have lead to the development of a corticocancellous block graft harvested from the iliac crest region. This study evaluates the clinical indications of these allogenic graft materials to replace compromised alveolar bone defects both horizontal and vertical in nature. The analysis is supported by re-entry procedures and histologic evaluations to substantiate predictability.     

Controlled subperiosteal tissue expansion to facilitate GBR for the placement of endosseous dental implants

The success of endosseous dental implants is enhanced when sufficient bone is present to stabilize the implant. If adequate bone for full coverage of the implant is not possible, then the use of guided bone regeneration to regenerate the missing bone has been shown to be a predictable solution. Defect size can often limit the amount of soft tissue available for coverage of the membrane, which is essential in obtaining an optimal result when using regenerative and osseointegrative principles. The treatment philosophy demonstrated in this case report uses controlled subperiosteal tissue expansion to facilitate the incorporation of guided bone regeneration with the subsequent placement of endosseous dental implants. This treatment modality provided a successful treatment for an otherwise compromised case.