Predictable synthetic bone grafting procedures for implant reconstruction: part two

When teeth are missing, the surrounding bone and soft tissue is challenged as a result of the natural resorptive process or from traumatic destruction subsequent to extraction. The diminished structural foundation for prosthetic reconstruction with or without implants can therefore be compromised. Recent technological innovations in computer hardware and software have given clinicians the tools to determine 3-dimensional anatomy, quality, and density of bone, which can aid in the diagnosis and treatment planning for reparative or augmentative grafting procedures. Advanced synthetic bioactive resorbable bone graft (SBRG) materials and innovative surgical techniques have made it possible to predictably alter the defective site to create favorable osseous conditions for implant placement. The synthetically derived, resorbable, cluster-like, hydrophilic, particulate, bone-grafting material, having similar mechanical and chemical properties as the host bone, can provide the means to modify existing bone topography by aggressively overpacking the material for ridge preservation, ridge augmentation, or to enhance the bony site and subsequent prosthetic rehabilitation. Since bone does not bridge in empty spaces, the aggressive overfill, commonly referred to as force mineralization, controls excessive bleeding and eliminates voids. Part 1 of this 2-part series presented evidence of safety and effectiveness of the SBRG materials, crystal morphology, chemical properties, and characterization through animal and clinical studies. The osteoconductive cluster particulate assists in the bridging of lost bone anatomy by chemotactic response and resorption concurrent with regeneration of new bone formations. Part 2 demonstrates specific clinical handling characteristics and use of this material to facilitate implant placement and/or prosthetic reconstruction through clinical case applications. Additionally, in a unique clinical presentation, a composite graft mixture consisting of the SBRG and dense, ceramic, bovine-derived HA (sintered at 1,150 degrees C) was compared using electron microscopy.     

Piezoelectric surgery in implantology: a case report--a new piezoelectric ridge expansion technique

The purpose of this preliminary article is to present a new surgical technique that, thanks to the use of modulated-frequency piezoelectric energy scalpels, permits the expansion of the ridge and the placement of implants in single-stage surgery in positions that were not previously possible with any other method. The technique involves the separation of the vestibular osseous flap from the palatal flap and the immediate positioning of the implant between the 2 cortical walls. The case report illustrates the ridge expansion and positioning of implants step by step in bone of quality 1 to 2 with only 2 to 3 mm of thickness that is maintained for its entire height. To obtain rapid healing, the expansion space that was created for the positioning of the implant was filled, following the concepts of tissue engineering, with bioactive glass synthetic bone graft material as an osteoconductive factor and autogenous platelet-rich plasma as an osteoinductive factor. The site was covered with a platelet-rich plasma membrane. A careful evaluation of the site when reopened after 3 months revealed that the ridge was mineralized and stabilized at a thickness of 5 mm and the implants were osseointegrated.     

Ridge-splitting technique with simultaneous implant placement

Bone augmentation procedures are routinely required before dental implant placement. Several techniques for this procedure may be considered, such as guided bone regeneration, bone block grafting, and ridge splitting for bone expansion. These case reports describe the technique for ridge splitting and gradual expansion in the maxilla and the mandible. Simultaneously, dental implants were placed within the split ridge, surrounded by the particulate bone graft and covered by a resorbable membrane. Six months later, the implants were uncovered followed by impression and final restoration with implant-supported porcelain-fused-to-metal crowns.     

Evaluation of a low-temperature calcium phosphate particulate implant material: physical-chemical properties and in vivo bone response.

A study was conducted to evaluate the osteoconductive ability of a particulate, low-temperature hydroxylapatite (HA(LT)) material (OsteoGen; Impladent, Holliswood, NY). An implantable chamber model was used to determine the ability of this material to encourage bone ingrowth into channels lined with either rough-surfaced titanium or rough-surfaced plasma-sprayed hydroxylapatite. The HA(LT) material increased bone ingrowth into the titanium-lined channels comparable with that in plasma-sprayed hydroxylapatite-coated channels. It was incorporated into ingrowing bone without intervening soft tissue, with the bone bonding directly to the material surface in much the same fashion as it bonds at the plasma-sprayed hydroxylapatite surface. Mechanical testing of the ingrown bone showed no weakness because particles were incorporated. At 12 weeks, the particles began to show signs of dissolution. It was concluded that the HA(LT) material is a biocompatible, osteoconductive material that conducts bone ingrowth in much the same way as high-temperature particulate hydroxylapatite ceramics. This material has the additional desirable property of being slowly resorbable, a beneficial characteristic for many bone-filling applications.     

Sinus lift grafts and endosseous implants. Treatment of the atrophic posterior maxilla.

Patients from multicenters were treated with sinus lift graft operations and placement of implants. Surgical procedures healed uneventfully with minimum pain, swelling, or morbidity. Grafts healed with few complications or failures. Implants placed into the grafts support prosthetic reconstruction and are predictable over time. The question of what graft material to use is discussed. Grafts of non-resorbable HA (Interpore 200), bovine cortical HA (Bio-Oss), resorbable HA (OsteoGen), and freeze-dried demineralized bone powder and granules are presented. Results of biopsy, histometry, backscattered electron microscopy, cell labeling, and special stain suggest consistent bone growth into a variety of graft materials. In the authors' opinion investigation must continue to 1. Determine the healing time for different graft materials. At present, anecdotal evidence suggests that sinus grafts of autogenous bone heal for 4 to 6 months; freeze-dried demineralized bone heals for 12 to 16 months; and alloplastic materials with freeze-dried demineralized bone heal for 9 to 11 months. 2. Evaluate histologic evidence of bone growth into different bone replacement graft materials. 3. Evaluate the long-term follow-up and success of implants placed within sinus grafts. 4. Determine the remodeling potential of different hard tissue graft materials under implant functional loads.     

Reconstruction of atrophied anterior mandible with an inlay technique and resorbable miniplates: a case report

This case report describes an inlay augmentation procedure with resorbable bone plates and fixation screws in a case of vertical atrophy of the anterior mandible. After 3 months from the surgery, vertical bone height augmentation was evaluated, and at the time of implant insertion, core biopsies from the grafted area were taken. Moreover, 8 months after the start of prosthetic loading, radiographic assessments showed no pathological signs. This case report shows that the effectiveness of resorbable plates during the graft healing process is similar to that of titanium plates.     

Titanium Mesh Technique in Rehabilitation of Totally Edentulous Atrophic Maxillae: A Retrospective Case Series

Background: This study evaluates implant‐borne prosthetic rehabilitation of 10 totally edentulous atrophic maxillae after bone reconstruction with a titanium‐mesh technique and particulate bone graft. Methods: Ten atrophic maxillae were reconstructed with 19 titanium meshes and particulate autologous‐heterologous bone. Maxillae were rehabilitated at least 5 months, with placement of 67 implants connected to the prostheses after an additional 4 months of rehabilitation. Cases were evaluated retrospectively in terms of complication rates, particularly on the amount of mesh exposure, implant survival, and success rates at the end of follow‐up. Results: In seven cases, two meshes were prematurely exposed (within 4 to 6 weeks), and five were exposed later (after 4 to 6 weeks). Only two of the later exposures extended >1 cm². Nevertheless, reconstructions allowed implant placement and prosthetic rehabilitation in all cases. Two implants were lost before loading. After mean follow‐up at 39.3 (20 to 56) months since prosthetic loading, all 65 implants were functional (100% implant survival), but 15 implants demonstrated a peri‐implant mean bone resorption of 2.96 mm increased bone loss, yielding a cumulative implant success rate of 76.9%. No prosthetic problem was observed. Conclusions: Use of titanium mesh with particulate bone can be considered a valid option in reconstructing atrophic maxillae to allow for implant‐borne prosthetic rehabilitation. A high level of dehiscence did not compromise final outcome.     

多孔块状β-磷酸三钙兔颅骨骨膜下埋植引导成骨的组织学观察

目的 通过组织切片观察。了解多孔块状β-磷酸三钙（β-TCP）在皮质骨表面引导成骨过程中的组织学表现及可吸收机理。方法 将多孔块状β-TCP陶瓷在兔颅骨骨膜下埋植，实验标本常规石蜡切片，HE染色和Masson三色染色，显微镜下观察各组标本的组织学表现，并和羟基磷灰石（HA）作比较。结果 β-TCP及HA陶瓷均能引导新骨生成，新骨大量从颅骨表面长入材料内，颅骨骨膜下无明显成骨，并观察到大量多核异物巨细胞吞噬β-TCP的现象。结论 β-TCP能引导大量新骨生成，可以作为萎缩牙槽嵴加高的代用品，细胞对材料的吞噬作用是β-TCP具有可吸收性的重要因素之一。     

Placement of implants into ridges grafted with bioplant HTR synthetic bone: histological long-term case history reports

Following alveolar ridge grafting procedures for ridge preservation, for example, the immediate filling of extraction sockets, and ridge augmentation, for example, the building up of the atrophic jawbone, punch biopsies were obtained at various times postextraction prior to the placement of endosseous root-form implants. These histological sections provided an opportunity to study the bony regenerative response to an osteoconductive synthetic graft material and longer term interactions over a period from 8 months to 12 years. The formation and remodeling of healthy dense lamina of bone in areas where bone voids previously existed either from healed or immediate extraction sockets or where there was jawbone atrophy resulting from multiple tooth loss was observed. The grafting procedures enabled dentists to place implants into sites that would have been impossible if not for these preimplant grafting procedures. The jawbone areas studied involved grafted single sites and quadrants as well as full arch augmentation with a calcified microporous copolymer (Bioplant HTR Synthetic Bone, Bioplant Inc, South Norwalk, Conn) graft material. Retrospective case reports of 24 patients were followed radiographically and clinically to 12 years post-alveolar-ridge grafting and subsequently to 5 years after implants were placed into these augmented ridges. Implant and grafting histories from 4.7 months to 17 years are reported for three of these patients. General applications of synthetic bone grafting before implant placement are recommended.     

Localized ridge augmentation with a block allograft followed by secondary implant placement: a case report

A 37-year-old woman presented with severe ridge resportion of the mandibular left first molar and requested placement of a dental implant in lieu of a traditional fixed partial denture. The patient preferred an allograft to avoid a second surgical site to harvest an autogenous bone graft. A new solvent-dehydrated, allogeneic, corticocancellous bone graft material was selected for the case. The allograft was shaped to fit the defect, rehydrated in sterile saline, stabilized with fixation screws, and covered with platelet-rich plasma and a resorbable collagen membrane prior to soft tissue closure. Four months later, the bone graft was incorporated into the host tissue without complications and effectively expanded the ridge from 3 to 9 mm. The implant osseointegrated and was restored with a computer-milled abutment and single crown. The allograft maintained its strength and structural integrity, and was well-tolerated by the host tissues. A screw-design implant was placed in the previously augmented bone site and successfully restored with a computer-milled post and cemented single-tooth prosthesis. The allograft material was a highly effective modality for restoring the case, and it may significantly reduce the need to obtain autogenous bone from a secondary site.     

Ridge enlargement using deproteinized bovine bone and a bioresorbable collagen membrane: a tomodensitometric, histologic, and histomorphometric analysis

The aim of this paper was to study, through a clinical case report, the behavior of deproteinized bovine bone (Bio-Oss) covered with a resorbable barrier membrane (Bio-Gide) when used as an onlay grafting material to obtain alveolar bone ridge enlargement. The presence of an existing bone edge allowed placement of an MK III groovy implant and creation of the required space for ridge enlargement, using xenograft particles (Bio-Oss) covered with a resorbable barrier membrane (Bio-Gide), during the same surgical stage. Recording of anatomical landmarks in the three dimensions of space in relation to implant position allowed precise assessment of the graft behavior during the tomodensitometric examinations performed at 6 and 18 months postsurgery. A biopsy was performed at 9 months postsurgery for histologic and histomorphometric analyses. The tomodensitometric images allowed observation of the preservation of the grafted bone volume. The histologic analysis revealed vital bone formation with the remaining Bio-Oss particles; the histomorphometric analysis, at this stage, provided similar percentages of Bio-Oss (27.94%) and newly formed bone (24.07%). This clinical example confirms the biocompatible and osseoconductive properties of Bio-Oss, as well as stability of the bone graft volume. These different elements testify to the advantage of its use for alveolar ridge enlargement.     

钛网成形自体颗粒骨修复下颌骨缺损并同期种植的实验研究

目的 观察犬钛网成形自体颗粒骨移植修复下颌骨节段性缺损并同期植入钛种植体后的骨愈合和骨结合情况.方法 5只Beagle犬,一侧下颌骨制备长40 mm的节段性缺损;钛网成形修复下颌骨缺损.将切除后的下颌骨和自体髂骨剪成直径约2mm颗粒,骨皮质、骨松质体积比3∶1混合,紧密充填在钛网内,将2枚纯钛种植体埋置于颗粒骨内,术后6个月处死动物.用下颌骨X线片、组织学切片、扫描电镜以及能谱分析观察钛网内颗粒骨愈合以及种植体骨结合的情况.结果 钛网成形自体颗粒骨移植重建后的下颌骨外形满意,功能正常、颗粒骨成骨良好、结构优良,未见明显骨吸收.同期植入的种植体能够与周围骨组织形成良好的骨结合,并有促进邻近骨组织结构优化的趋势.结论 钛网成形自体颗粒骨移植是一种修复下颌骨节段性缺损的好方法,当修复后下颌骨形态良好、骨质优良、骨量充足时可以同期植入种植体.     

钛网结合异体骨移植和人骨形成蛋白在上颌前牙种植前牙槽嵴骨增量中的应用研究（附1例报告）

编者按：本刊特邀美国德克萨斯健康研究中心牙学院Bing-Yan Wang副教授介绍1例在上颌前牙牙槽骨严重缺损区实现骨增量的病例。在拔牙同期用异体骨和Bio-Mend延展膜进行引导骨再生术后未获得满意骨量的情况下,无法进行种植手术,术者用钛网结合异体骨移植材料和人骨形成蛋白在种植体植入前修复上前牙区部分牙缺失部位的牙槽骨缺损,最终获得成功。通过这种方法扩大了在上前牙牙槽骨严重骨缺损区种植的适应证,为患者提供了除自体骨移植以外的另一个选择。     

A new osteoconductive resorbable hydroxylapatite graft material that restores bony defects with viable bone

The reconstruction and repair of a large mandibular bony defect following an extraction was accomplished using resorbable hydroxylapatite OsteoGen (HA RESORB). The complete repair of the defect and alveolar architecture with dense regenerated bone was achieved prior to the surgical insertion of an endosseous titanium implant. The implant was used for additional support for a long span fixed prosthesis. Histological studies of harvested bone core specimens of the resorbable hydroxylapatite grafts at four months and 14 months are compared and discussed in this report.     

Harvesting bone in the recipient sites for ridge augmentation

A modified ridge augmentation technique is introduced for augmenting deficient alveolar ridges in preparation for endosseous implant placement. The technique is based on the principles for guided bone regeneration, in which a created space is kept isolated from the surrounding soft tissues by a resorbable membrane with an excellent extended resorption profile, thus permitting the accrual of bone-formative elements into the graft site. The absorbable membrane is propped up by an autogenous mixture of native corticocancellous bone cores taken in the graft site and reduced to smaller particle sizes and osseous coagulum collected in bone traps and with a special bone scraper. The major advantage of this technique is that all the autogenous bone graft material is obtained from the actual graft site, avoiding second remote intra- or extraoral surgical sites and attendant morbidities. Ridges augmented with this technique permit optimal endosseous implant placement.     

Alveolar ridge augmentation using a resorbable copolymer membrane and autogenous bone grafts. An experimental study in the rat

The aim of the present study was to compare the result of maxillary alveolar ridge augmentation by the combined use of mandibular bone grafts and resorbable membranes (Resolut), with that achieved by the use of the same type of bone graft combined with the placement of e-PTFE membranes (Gore-Tex). The experiment was carried out in 30 rats. In one side of the maxillary jaw, the edentulous alveolar ridge between the incisor and the first molar was augmented by means of an autogenous mandibular bone graft that was fixed with a titanium microimplant and covered with a resorbable membrane. The contralateral side, serving as control, was treated in the same way, with the difference that an e-PTFE membrane was placed over the bone graft. Histological analysis at 15, 30, 60, 120 and 180 days after surgery demonstrated that, in both test and control sites where the membrane was properly adapted and not exposed, the bone grafts presented no resorption and were integrated into the maxillary bone at the recipient site. In cases where the membrane was exposed, however, the bone grafts presented extensive resorption and lack of continuity between the graft and the recipient bed. At 60-180 days after surgery, the exposure of both types of membrane had frequently led to complete resorption of the grafts, encapsulation of the titanium microimplant by fibrous connective tissue, or exfoliation of the microimplant. It is concluded that alveolar ridge augmentation can be predictably accomplished by combining mandibular bone grafting with the placement of resorbable or non-resorbable membranes according to the GTR principle, provided that the membrane is properly adapted over the graft and complete closure of the treated area is maintained during healing.     

A method using vestibulo-sulcoplasty combining a split-thickness skin graft and a palatal keratinized mucosa graft for peri-implant tissue secondary to oral cancer surgery

Twelve patients presented with oral submucosal fibrosis and loss of keratinized gingiva in a compromised vestibule of a severely deficient mandibular edentulous ridge secondary to oral cancer surgery. They received implant rehabilitation with a total of 49 fixtures without major bone graft augmentation. To overcome vestibular compromise, soft tissue management consisting of simultaneous vestibulo-sulcoplasty, split-thickness skin graft (STSG), and palatal keratinized mucosa graft (KMG) was performed as a second stage when healing abutment was transferred to replace the cover screw of the dental implant. Postoperative follow-up of all patients consisted of clinical and radiographic examinations for an average of 4 years, revealing good stability of implant fixtures with a 91.8% success rate and generally healthy peri-implant tissue, the latter with an average sulcus depth of 2.9 +/- 0.6 mm. Satisfactory results were also demonstrated regarding improved morphology of the vestibule, cosmetics, and prosthetic functionality. Vestibulo-sulcoplasty combining STSG and palatal KMG offers a stable and convenient method for rebuilding peri-implant tissue without need for bone grafting in selected patients who have compromised atrophic ridges secondary to cancer surgery.     

自体牙移植物在骨增量中的研究进展

由于外伤、感染、糖尿病、绝经后骨质疏松症等病症所引起的骨量不足、种植条件较差的现象在临床中极为普遍,骨增量技术应运而生.骨移植是最常用的骨增量技术,主要来源包括自体骨移植、同种异体骨移植、异种骨材料和人工合成骨材料.近年来,自体牙由于优越的生物相容性及易获得性,逐渐成为一种新兴骨替代材料.该文比较了近年发表的关于不同类...     

A 6-year unloaded hydroxyapatite-coated dental implant placed into an extraction socket in conjunction with nonresorbable hydroxyapatite grafting material: histologic evaluation

A submerged hydroxyapatite (HA)-coated implant placed into a fresh extraction socket in conjunction with a nonresorbable HA graft was harvested after 6 years of unloaded healing. The implant and surrounding bone were processed for histologic analysis. The HA coating appeared to be stable and homogenous. An excellent bone-to-implant contact could be found along the entire implant length. No signs of HA resorption or detachment were found. The HA graft was still recognizable histologically around the apical third of the implant. Light microscopy revealed a good osteoconductive ability of the HA particles, which did not show any signs of remodeling or resorption. These findings suggest that HA-coated implants may be able to maintain optimal osseointegration over time, even in the absence of loading.     

Alveolar ridge augmentation with bioactive glass ceramics: a histological study

A particulate BGC (bioactive glass ceramics), has been developed as a new bone graft biomaterial for alveolar ridge augmentation and has been evaluated by simulated animal models. Five beagle dogs were used in this investigation. Prior to augmentation the mandibular posterior teeth of the animals were extracted. Three months after the extractions, the porous BGC particles were packed into the subperiosteal tunnels in the ridges with a special syringe. The animals were killed at different time intervals and the specimens were examined by light microscopy, scanning electron microscopy (SEM), and X-ray energy dispersive analysis (EDAX), respectively. The results of this study indicate that the BGC particles are firmly combined with the adjacent hard and soft tissues by the bone bonding interface between the implants and the alveolar bone, and by the ingrowth of bone or fibrous connective tissue into the interspaces and the pores of the particles. The results have demonstrated that particulate BGC with pores is an excellent implant material for alveolar ridge augmentation because of its very good biocompatibility.