Postoperative tomographic assessment of veneer bone grafting with implant placement in the maxillary anterior region

Various ridge augmentation and sinus lift procedures were performed in severely resorbed alveolar crests of a maxilla to provide some volume for implant treatment. It was reported that the outcome of maxillary sinus lift procedures was evaluated with conventional tomography or computerized tomography, and that grafted bone around implants markedly progressed in resorption, particularly at the implant apex. However, veneer bone grafting with implant placement has not been evaluated after treatment with imaging techniques. Therefore, the purpose of this study was to assess veneer bone grafting after maxillary anterior implant treatment. Seven patients with a mean age of 24 years, with implants placed in the maxillary anterior region with or without autogenous veneer bone grafting were postoperatively examined using conventional tomography. On tomograms, the ratio of bone-to-implant contact and the area of bone were measured in labial bones with bone grafts, and they were compared with the values without bone grafts. In cases with bone grafting, the average ratio of bone-to-implant contact was 63.6%, whereas 81.8% was formed in cases without bone grafting. The average area of bone was 12.9 mm and 23.4 mm in patients with and without bone grafting, respectively. No significant difference was found between the implants with and without bone grafts. Resorbed labial bone was observed in the maxillary anterior region with and without veneer bone grafting.     

Survival Rate for Implants Placed in the Posterior Maxilla With and Without Sinus Augmentation: A Comparative Cohort Study

Background: The reduced bone height and proximity of the maxillary sinus are the most common limitations for placement of dental implants in the posterior maxilla. Reconstruction of the atrophic posterior maxilla can be performed with a sinus augmentation procedure. The aim of this cohort study is to compare the survival rate of implants placed in augmented sinus to implants placed in native bone in the posterior maxilla. Methods: This study was designed as a prospective cohort study and included consecutively treated patients. Patients who required the sinus augmentation (test group) were treated according to the two‐stage technique. Patients were scheduled for follow‐up evaluation at 3, 6, and 12 months after implant placement and then every 6 months for ≤6 years. Results: One hundred and five patients with 393 implants were enrolled in the study. Two hundred and one implants were placed after preliminary sinus floor grafting in 41 patients. The control group contained 64 patients with 192 implants that were placed in pristine bone of the posterior maxilla. The cumulative implant survival rates were 86.1% and 96.4%, respectively. The difference between the two groups was highly significant (P <0.005). Conclusions: These findings show that implants placed in augmented sinuses had a lower survival rate compared to implants placed in pristine bone. All the implant failures in the augmented sinuses occurred before the prosthetic rehabilitation. Moreover, it should be considered that most of the failures were observed in few patients, thus suggesting cluster behavior.     

Maxillary alveolar ridge reconstruction with nonvascularized autogenous block bone: clinical results.

PURPOSE: The purposes of this study were to evaluate the clinical success of bone reconstruction of the severely atrophic maxilla using autogenous bone harvested from the anterosuperior edge of iliac wing and to analyze the clinical success and the marginal bone level of dental implants placed 4 to 5 months after bone grafting and before prosthetic rehabilitation. PATIENTS AND METHODS: Fifty-six patients (18 men, 38 women) aged 27 to 63 years were included in the study and required treatment for maxillary atrophy. All patients selected were scheduled for onlay bone graft and titanium implants in a 2-stage procedure. The dental implants were inserted 4 to 5 months after grafting. RESULTS: No major complications were observed from the donor sites. A total of 129 onlay bone grafts were used to augment 56 severely resorbed maxillas. Three out of 129 bone grafts had to be removed because of early exposure occurring with bone grafts placed to increase the vertical dimension of the alveolar ridge. One hundred sixty-two implants were placed in the area of bone augmentation. Seven implants failed to integrate and were successfully re-placed without any need for additional bone grafting. The clinical measurements for bone resorption around implants revealed a mean bone loss of 0.05 mm (+/- 0.2); the marginal bone level evaluated with periapical radiographies was 0.3 mm (+/- 0.4) at implant placement and 0.1 mm (+/- 0.3) 6 months after placement. CONCLUSION: The success rate of the block grafts was very good. The clinical and radiographic bone observations showed a very low rate of resorption after bone graft and implant placement. Therefore, on the basis of this preliminary study, iliac bone grafts (from the anterosuperior edge of the iliac wing) can be considered a promising treatment for severe maxillary atrophy.     

上颌窦底内提升同期植入种植体的临床效果观察

目的:观察单纯上颌窦内提升术同期牙种植修复的临床效果.方法:上颌后牙区牙槽骨严重吸收的36例患者,种植区剩余牙槽骨高度为(5.9±2.1)mm,行单纯上颌窦内提升同期牙种植术,共植入42枚种植体,其中瑞士Straumann种植体22枚、韩国奥齿泰SSⅡ种植体13枚、法国安多健种植体7枚.术后3～4个月,行上部结构修复,同时观察种植体的稳定性和种植体周围骨结合情况.随访期(12.2±3.6)个月.结果:36例患者上颌窦底提升高度(2.83±1.12)mnl,41枚种植体成功负载,种植体稳定,骨结合状况良好,无不良自觉症状.1枚种植体术后5周脱落,脱落2个月后重新种植,成功负载.结论:单纯上颌窦内提升同期牙种植术能有效治疗上颌窦底牙槽骨高度不足的上颌后牙缺失,手术创伤小,操作简便,并发症少,近期效果满意.     

The management of a severely resorbed edentulous maxilla using a bone graft and a CAD/CAM-guided immediately loaded definitive implant prosthesis: a clinical report

Functional reconstruction of an occlusion with severe residual ridge resorption is a clinical challenge. Removable prostheses are unsuccessful in situations with severe bone resorption. A patient with an edentulous maxilla received bone grafts from the anterior iliac crest to augment the maxillary alveolar residual ridges. The maxilla underwent bilateral sinus lift in the posterior area and onlay bone graft on the anterior maxilla using platelet-rich plasma. Eight endosseous implants were placed using a CAD/CAM surgical template approximately 6 months after the bone augmentation procedure. A prefabricated definitive implant-supported fixed complete denture was connected immediately after implant placement using a CAD/CAM-guided surgical implant placement protocol.     

Histologic evaluation of autogenous calvarial bone in maxillary onlay bone grafts: a report of 2 cases

Bone augmentation for implant dentistry has become a necessary procedure for a number of edentulous patients. Calvarial bone grafting constitutes an important tool in achieving maxillary augmentation and sinus elevation. Much effort has been directed toward improving graft survival and volumetric maintenance. The purpose of the present study was to evaluate the histologic results of the calvarial onlay graft for maxillary reconstruction before implant placement. Two patients underwent maxillary augmentation using autogenous calvarial onlay grafts. After a 4-month healing period, biopsies of the augmented regions were performed and implants were placed. The implants were loaded after 5 months and then clinically examined after 15 months of function. Biopsies showed that calvarial onlay grafts were well incorporated into the preexisting bone after a 4-month period. Histologic and histomorphometric findings demonstrated a living bone that showed features characteristic of mature and compact osseous tissue. The restored Implants were stable and osseointegrated after a 15-month period of follow-up. The use of calvarial onlay grafts can be a predictable and successful method to achieve maxillary augmentation, allowing appropriate placement of implants and stable prosthetic restorations.     

Dental implants and onlay bone grafts in the anterior maxilla: analysis of clinical outcome

PURPOSE: Loss of alveolar bone in the anterior maxilla may preclude implant placement or compromise positioning and thus diminish the final esthetic result of the restoration. Bone augmentation can overcome such difficulties but may affect osseointegration. The aim of this study was to report the outcome of buccal onlay bone grafting in the anterior maxilla in routine dental implant practice. MATERIALS AND METHODS: Seventeen consecutive patients (12 men and 5 women, mean age 31.4 years) received autogenous bone grafts from the mandibular symphysis to the anterior maxilla. A total of 35 Br?nemark System MK II implants were placed in grafted bone. RESULTS: Fifteen patients had a mean period of graft consolidation of 19.7 weeks (range 13 to 32 weeks). Two patients had simultaneous graft and implant placement; 1 implant failed to Integrate in this group. This represents a survival rate of 97.1% of implants in functional loading after a mean follow-up period of 153.6 weeks from occlusal loading (range 74 to 283 weeks). DISCUSSION AND CONCLUSION: Mandibular block onlay grafts appear to be a predictable method for augmenting the width of the anterior maxilla prior to implant placement.     

Sinus elevation with alloplasts or xenogenic materials and implants: an up-to-4-year clinical and radiologic follow-up

PURPOSE: The clinical and radiologic results of bone substitute application in the sinus elevation procedure were evaluated for up to 4 years after a grafting procedure followed by implant placement. MATERIALS AND METHODS: Between 1997 and 2001, augmentation of the maxillary sinus floor with alloplastic or xenogenic materials was performed in 34 nonsmoking patients with generally good health. However, only 18 patients attended all of the required annual clinical and radiographic examinations and thus were included in the study. Mean follow-up after implantation was 29 months. RESULTS: At the second-stage surgery all the implants were osseointegrated, except for 1 Frialit-2, which was removed. Following prosthetic rehabilitation no implant was lost after 4 years of function, for a prosthetic success rate of 100%. The cumulative implant survival rate after 48 months was 97% (36 of 37 implants). DISCUSSION: Osseointegrated implants are a reliable treatment option for restoring the posterior maxilla, and final predictability was not influenced by their placement in augmented areas after sinus elevation with bone substitutes. CONCLUSIONS: The survival rate obtained with this study is similar to that expected for implants placed in nongrafted areas. This study showed that alloplasts and xenogenic materials are reliable for bone regeneration in the subantral cavities, as they showed very low resorption in the present study.     

Clinical Outcomes of an Osteotome Technique and Simultaneous Placement of Neoss Implants in the Posterior Maxilla

Background: Insufficient bone volume often hamper placement of dental implants in the posterior maxilla. Purpose: The aim of the present clinical study was to evaluate retrospectively the clinical outcome of implant placement in the resorbed posterior maxilla using an osteotome technique without adding any grafting material. Materials and Methods: Twenty patients with 5 to 9 mm of residual alveolar bone height in the posterior maxilla received twenty‐nine implants (Neoss Ltd., Harrogate, UK) using an osteotomy technique without bone grafts. Intraoral radiographs were taken before and after implant placement, at the time of loading and after 11 to 32 months of loading (mean 16.4 months), to evaluate bone formation below the sinus membrane and marginal bone loss. Implant stability measurements (Osstell^TM, Gothenburg, Sweden) were performed after implant installation and at abutment connection 5 months later. All implants were installed with the prosthetic platform level with the bone crest. Results: No implant was lost giving a survival rate of 100% after a mean follow‐up time of 16.4 months. The average vertical bone height was 7.2 ± 1.5 mm at placement and 10.0 ± 1.0 mm after 11 to 32 months. The average increase of 2.8 ± 1.1 mm was statistically significant. There was a statistically significant improvement in implant stability from 70.7 ± 9.2 implant stability quotient (ISQ) at placement to 76.7 ± 5.7 ISQ at abutment connection, 5 months later. The mean marginal bone loss amounted to 0.7 ± 0.3 mm after 11 to 32 months of loading. Conclusion: It is concluded that the osteotome technique evaluated resulted in predictable intrasinus bone formation, firm implant stability, and good clinical outcomes as no implants were lost and minimal marginal bone loss was observed.     

Maxillary sinus floor augmentation using bioactive glass granules and autogenous bone with simultaneous implant placement. Clinical and histological findings

This clinical study was undertaken to: 1) evaluate the use of bioactive glass Biogran combined with autogenous bone as grafting material for maxillary sinus augmentation with simultaneous implant placement using radiography and histology; and 2) document the short-term post-loading success of implants inserted in sinus cavities augmented with this material. Unilateral or bilateral sinus augmentation was performed in 12 patients with 3-5 mm of alveolar crestal bone height in the posterior maxilla prior to grafting. The sinuses were grafted with bioactive glass mixed in a 4:1 ratio with autogenous bone. Simultaneously, 2-3 threaded titanium implants were inserted into the augmented sinuses. Second stage surgery was carried out 9 to 12 months post implantation. At abutment connection, 10 core biopsy specimens were taken from different grafted sites and evaluated histologically. All 27 implants were clinically stable at second stage surgery. A mean increase in mineralized tissue height of 7.1 +/- 1.6 mm was evident when comparing the pre-surgical CT scans with those performed 9-12 months following the sinus augmentation procedure. Evaluation of the cores yielded a mean of 30.6 +/- 5.7% of bone tissue in the grafted sites. One implant failed during the prosthetic phase while the remaining 26 implants were stable 12 months post loading. This study suggests that Biogran/autogenous bone graft combination used in one-stage sinus augmentation yields sufficient quality and volume of mineralized tissue for predictable simultaneous implant placement in patients with 3-5 mm of bone height prior to grafting.     

Endosseous implants and bone augmentation in the partially dentate maxilla: an analysis of 17 patients with a follow-up of 29 to 101 months

PURPOSE: The aim of this study was to analyze the survival rate of endosseous implants placed in the partially dentate maxilla treated with sinus inlay block bone grafts. MATERIALS AND METHODS: Seventeen patients were subjected to bone augmentation procedures prior to or in conjunction with implant placement. Bone volumes were regarded as insufficient for implant treatment unless a bone grafting procedure was performed. The patients were treated with sinus inlay block bone grafts and endosseous implants in a 1- or 2-stage procedure. A total of 69 implants were placed in the patients who were followed for 29 to 101 months (mean, 53.1 months). The retrospective patient group was also prospectively followed using a standardized clinical and radiographic study design. RESULTS: The implant survival rate was 91.3% (63/69). All implants were lost during the period from abutment connection to connection of the definitive prosthesis. All bone grafts were stable. Bone grafts supported 48 implants, of which 5 failed (10.4%). In the residual bone, 21 implants were placed, of which 1 failed (4.8%). All patients received a fixed partial prosthesis, which was stable during the follow-up period. CONCLUSION: The results of this investigation revealed a satisfactory clinical outcome of implant placement in grafted partially dentate maxillae after a mean follow-up of 53.1 months.     

Stability Evaluation of Implants Integrated in Grafted and Nongrafted Maxillary Bone: A Clinical Study from Implant Placement to Abutment Connection

Background: Clinical studies have shown a higher degree of implant failures in grafted bone compared with normal nongrafted maxillary bone. Additionally, a prolonged time for integration of titanium implants in grafted block bone has been shown by means of resonance frequency analysis (RFA). Purpose: The aim of this prospective study was to compare the stability of implants placed in particulate bone, onlay block bone, interpositional bone, and nongrafted maxillary bone during the early phase of osseointegration using RFA and implant failure. Material and Methods: Thirty‐five patients with edentulism in the maxilla were included in the study. In all, 260 Astra Tech TiOblast? implants (Astra Tech AB, Mölndal, Sweden) were installed. Twenty‐five of these patients had severe maxillary atrophy and were treated with iliac bone grafts 5 to 6 months prior to implant placement, 19 with lateral onlay block grafts on one side (group A, 38 implants) and particulate bone for lateral augmentation on the other (group B, 38 implants). These 19 patients also got bilateral sinus floor augmentation with particulate bone (group C, 76 implants). Six patients had an unfavorable sagittal relation between the jaws and underwent a LeFort I operation with interpositional bone blocks grafted to the nasal and sinus floors (group D, 48 implants). The remaining 10 patients could be treated with implants without bone augmentation and served as control (group E, 60 implants). RFA was performed at implant placement and abutment connection 6 months later and an implant stability quotient (ISQ) value was given for each implant. Results: Four implants (1.5%) were found mobile at abutment connection and removed (two in group A and two in group D). RFA showed a slight increase in stability from installation to abutment connection but the differences were not statistically significant in any of the groups (Wilcoxon signed rank test for comparison of paired data). Implants installed in group D had a significantly lower ISQ value at both measurements compared with the other groups (Wilcoxon Rank Sum test for comparisons of independent samples, p = .05). Conclusion: It is concluded that TiO₂‐blasted implants placed in nongrafted and grafted maxillary bone using a two‐staged protocol show similar stability during the early phase of osseointegration. Patients reconstructed with interpositional bone graft after a LeFort I osteotomy showed lower implant stability values than nongrafted patients and other grafting techniques.     

Bone reformation with sinus membrane elevation: a new surgical technique for maxillary sinus floor augmentation

Background: Various maxillary sinus floor augmentation techniques using bone grafts and bone substitutes are frequently used to enable placement of dental implants in the posterior maxilla. A previous case report demonstrated the possibility of promoting bone formation in the sinus by lifting the membrane without using a grafting material. However, the predictability of the technique is not known. Purpose: The aim of this study was to investigate whether sinus membrane elevation and the simultaneous insertion of titanium implants without additional grafting material constitute a valid technique for bone augmentation of the maxillary sinus floor. Materials and Methods: The study group comprised 10 patients in whom a total of 12 maxillary sinus floor augmentations were performed. A replaceable bone window was prepared in the lateral sinus wall with a reciprocating saw. The sinus membrane was dissected, elevated superiorly, and sutured to the sinus wall to create and maintain a compartment for blood clot formation. One to three dental implants were inserted through the residual bone and protruded at least 5 mm into the maxillary sinus. The bone window was replaced and secured with the overlying mucosa. Bone height was measured directly at each implant site at the time of insertion. Resonance frequency analysis (RFA) was performed on each implant at the time of initial placement, at abutment surgery, and after 12 months of functional loading. Computed tomography (CT) was performed in the immediate postoperative period and 6 months later, prior to exposure of the implants. Results: A total of 19 implants (Brånemark System®, TiUnite?, Nobel Biocare AB, Gothenburg, Sweden) in lengths of 10 to 15 mm were placed, with an average residual bone height of 7 mm (range, 4–10 mm). All implants remained clinically stable during the study period. Comparisons of pre‐ and postoperative CT radiography clearly demonstrated new bone formation within the compartment created by the sinus membrane elevation procedure. RFA measurements showed mean implant stability quotient values of 65, 66, and 64 at placement, at abutment connection, and after 12 months of loading, respectively. Conclusions: The study showed that there is great potential for healing and bone formation in the maxillary sinus without the use of additional bone grafts or bone substitutes. The secluded compartment created by the elevated sinus membrane, implants, and replaceable bone window allowed bone formation according to the principle of guided tissue regeneration. The precise mechanisms are not known, and further histologic studies are needed. Sinus membrane elevation without the use of additional graft material was found to be a predictable technique for bone augmentation of the maxillary sinus floor.     

The influence of mandibular dentition on implant failures in bone-grafted edentulous maxillae

PURPOSE: To evaluate the influence of mandibular dentition on the performance of maxillary implants prior to definitive prosthesis attachment in maxillae that have been reconstructed with autogenous bone grafts. MATERIALS AND METHODS: A retrospective review of 90 consecutive patients, 31 men and 59 women, with a mean age of 57.4 years, was conducted. All patients underwent treatment planning to receive endosseous implants in the edentulous maxilla in conjunction with autogenous bone grafting. During the time from implant and/or bone graft placement until placement of the definitive restorations in the maxillae, the mandibular dentitions were recorded and categorized into 6 groups based upon the presence and distribution of teeth. RESULTS: Of 643 implants placed, 118 (18.4%) were lost between implant placement and definitive prosthesis placement. The type of mandibular dentition was significantly associated with implant failure during this time interval (P < .001). In particular, the patients with implants opposing unilateral occlusal support showed the highest rate of implant failure (43.8%, or 28 of 64 implants). Implants that opposed a mandibular implant-supported fixed prosthesis demonstrated an implant failure rate of 14.3% (10 of 70), and in patients with a removable mandibular denture, the implant failure rate was 6.2% (4 of 65 implants failed). The overall mean patient follow-up was 64.2 months. At 60 months, the cumulative implant failure rate based on the Kaplan-Meier method was 20.2%. DISCUSSION: Unfavorable concentration of forces on the maxilla may contribute to increased risk of implant failure. CONCLUSION: Effort should be made to create a favorable occlusion in the mandible, with attention being paid to broad distribution of occlusal contacts.     

不植骨上颌窦内提升术种植的临床疗效观察

目的 评价不植骨上颌窦内提升术在剩余牙槽骨高度为（RBH）3-8mm的患者种植修复中应用的临床效果。方法 对上颌后牙缺失,接受上颌窦内提升术,同期植入种植体但未进行植骨的10例患者进行回顾调查研究,这些病例术前的RBH范围均处于3~8 mm范围内。参照Cochran提出的种植体成功标准进行临床随访。通过影像资料测量术前种植体近远中位置RBH,并与术后1年相同位置进行对比,分析骨量变化。结果 10例病例的种植体均存留,根据标准评价1年种植成功率100%。病例术前RBH处于3.0-7.2mm之间,术后1年种植体边缘骨高度为3.6-9.2 mm,两者比较存在统计差异（P＜0.05）,种植区骨变化量（1.1±0.5）mm。结论 上颌窦内提升术在不植骨的条件下对于RBH 3-8mm的患者具有较好的短期临床效果。     

Ankylos种植系统在上颌窦外提升术同期牙种植中的应用

目的:对Ankylos种植系统在上颌窦提升术同期牙种植中的临床效果进行评价。方法:收集2008年1月至2010年1月期间,对46例上颌后牙区牙齿缺失要求种植的患者,于58侧上颌窦行外提升术,同期植入Ankylos种植体142枚,修复后随访观察1～3年。结果:观察期内142颗种植体,均无松动或脱落,曲面断层片检查种植体周围未见明显骨吸收阴影。结论:Ankylos种植系统应用于上颌窦提升术同期牙种植可获得满意的临床效果。     

Implant treatment without bone grafting in edentulous severely resorbed maxillas: a long-term follow-up study.

PURPOSE: To evaluate retrospectively the surgical outcome of tilted implants in severely resorbed edentulous maxillas as an alternative to bone grafting and the prosthodontic outcome of posterior extension bridges on tilted implants. PATIENTS AND METHODS: A total of 33 consecutive patients with severely resorbed edentulous maxillas participated in the study. In these patients, the maxillary bone volumes were insufficient for conventional placement of implants to support a fixed prosthesis. As an alternative to bone transplantation, a surgical technique with fenestration of the maxillary sinus to visualize the total amount of maxillary bone was used, followed by implant placement in a tilted manner along the anterior maxillary sinus wall. Thus, 4 to 6 implants of optimal length could be installed in each patient. Nineteen patients were included in this long-term follow-up study and were eligible for clinical evaluation at 8 to 12 years (mean, 10 years) after second-stage surgery. Each patient was examined clinically and radiographically. RESULTS: The 19 patients had a total of 103 implants. In 2 of these patients, 3 fixtures were lost during the first year after second-stage surgery. All other patients had all implants intact with functionally fixed dental prostheses, corresponding to a success rate of 97%. Radiographic examination showed bone resorption in 10% of the implants (10 implants in 5 patients with a total number of 27 implants), with a mean bone loss of 1.2 mm. Mucositis was seen in 47% of the patients. CONCLUSIONS: This long-term follow-up study (mean time, 10 years) demonstrates that patients with a severely resorbed maxilla can be treated successfully with conventional implant treatment. This simplified surgical technique can be an alternative to the more resource-demanding technique with bone grafting.     

Clinical,histological and histomorphometrical study of maxillary sinus augmentation using cortico-cancellous fresh frozen bone chips

BackgroundInsufficient bone volume in the posterior maxilla can be a major problem when placing dental implants. One of the goals of sinus augmentation procedures is the creation of sufficient volume of vital bone for the subsequent insertion and complete osseointegration of implants placed in the posterior maxilla.The aim of the present study was a clinical, histological and histomorphometrical analysis of maxillary sinus augmentation using human fresh frozen bone (FFB) allografts for maxillary sinus lift augmentation procedures.MethodsFifteen patients were treated with maxillary sinus augmentation using FFB. After three months, a bone biopsy was taken before implant placement in order to evaluate the healed bone from a histological and histomorphometrical point of view. After further three months, all implants were osseointegrated according to radiographic and clinical examinations. Abutment connection was performed and the patients received prosthetic restoration of the missing teeth.ResultsHistologically all the specimens showed signs of active remodelling and all the tissues were free of inflammatory cells. After 12 months of assessment, no implants had failed.ConclusionOur findings suggest that FFB is a biocompatible material that can be successfully used for maxillary sinus augmentation.     

Recombinant human bone morphogenetic protein-7 in maxillary sinus floor elevation surgery in 3 patients compared to autogenous bone grafts. A clinical pilot study

BACKGROUND/AIMS: This pilot study was designed to determine the clinical bone formation ability of a human recombinant DNA bone morphogenetic protein-7, also referred to as Osteogenic Protein-1 [OP-1] combined with a collagen carrier, implanted in the maxillary sinus of 3 patients. The results were compared with a group of 3 patients treated with sinus floor elevation and autogenous bone grafts. METHODS: 6 consecutive patients, 4 female and 2 male, between 48 and 57 years of age were treated by means of sinus floor elevation for insufficient bone height in the posterior maxilla for implant surgery. 3 patients, 2 female and 1 male, were treated with OP-1 attached to a collagen device. In these patients, 4 maxillary sinus grafting procedures according to Tatum's method were carried out. 1 g of collagen carrier containing 2.5 mg rhOP-1 mixed with 3 ml of saline was placed between the bony floor and the elevated mucosal lining of the most caudal part of the maxillary sinus, in order to increase the vertical bone dimension to place dental implants of a sufficient length. The 3 other patients, also 2 female and 1 male, with a total of 5 sinus sites, were treated with sinus floor elevation and autogenous iliac crest bone grafts. After 6 months, during dental implant preparation, bone cores were taken for histology. Thus, clinical, radiological and histological results of the 2 groups of 3 patients were compared. RESULTS: 6 months after sinus grafting with OP-1, in 1 male, well-vascularized bone-like tissue of good quality was observed clinically. This could be confirmed by histology. In the second, female, patient no bone formation was observed at all. A cyst-like granular tissue mass, without purulent content, was removed. In the 3rd, female, patient, who received bilateral sinus grafts, some bone-like formation was seen, however it showed flexible tissue which led to the decision that at 6 months after the sinus grafting, the implant placement had to be postponed. In all 5 autogenous grafted sinuses a bone appearance similar to normal maxillary bone was observed clinically as well as histologically and dental implants could be placed six months after sinus floor elevation surgery. CONCLUSIONS: These findings indicate that the OP-1 device has the potential for initiating bone formation in the human maxillary sinus within 6 months after a sinus floor elevation operation. However, the various findings in these 3 patients indicate that the behaviour of the material is at this moment insufficiently predictable, in this indication area. Further investigation is indicated before OP-1 can be successfully used instead of the "gold standard" autogenous bone graft.     

Clinical application of zygomatic implants for rehabilitation of the severely resorbed maxilla: a clinical report

PURPOSE: A zygomatic implant can be an effective device for rehabilitation of the severely resorbed maxilla. If zygomatic implants are used, onlay bone grafting or sinus augmentation would likely not be necessary. Where an anterior onlay bone graft is required, extension of the graft in the posterior region could be reduced. The results of the application of zygomatic implants in 9 patients and clinical evaluation of this therapy are reported. MATERIALS AND METHODS: Nine patients received a total of 15 zygomatic implants. Six to 8 months elapsed for healing before second-stage surgery was performed. Six months after prosthetic treatment, patients' opinions were solicited by means of a questionnaire. RESULTS: No implant was removed at the time of abutment connection surgery or during the follow-up period. In many cases, the zygomatic implant platform was located palatal to the alveolar ridge. However, no patients complained of any continuing speech impediment following superstructure fabrication. Computed tomograms taken before implant placement and 6 months after implant placement showed no sign of sinusitis in any patient. DISCUSSION: The zygomatic implant allows shorter treatment time and hospitalization. However, there can be some problems in the application of zygomatic implants. CONCLUSION: It is necessary to investigate long-term clinical prognosis.