倾斜种植体在上颌后牙区骨量不足患者中的应用

目的:探讨倾斜种植体作为一种避免上颌窦植骨的方法,应用于上颌骨后牙区骨量不足患者种植修复的可靠性。方法:2005年1月—2007年12月间,21例患者共27个固定桥修复上颌后牙缺失,分别使用ITI和Br覽nemark 2种种植系统共植入78颗种植体,其中34颗种植体采用倾斜植入,44颗轴向植入。所有患者均为上颌后牙区骨量不足无法直接接受常规种植体植入。种植体植入后常规愈合3个月,除1颗种植体失败外,其余种植体均功能性负载支持固定义齿修复,修复方式为黏结固位和螺丝固位。每例患者均于负载后12、24和36个月接受临床和放射学随访检查。采用SPSS11.0软件包对数据进行统计学处理。结果:上颌有1颗轴向种植体在术后2个月时失败,倾斜种植体无失败。随访时间为36个月。上颌轴向种植体的累积存活率为97.72%,倾斜种植体的累积存活率为100%,修复成功率为100%。随访期间,种植体周围软组织保持稳定,平均探诊深度和附着水平无明显变化。结论:倾斜种植体作为一种上颌骨后牙区骨量不足患者的治疗方法是可靠的,能有效避免植骨手术,并节约治疗时间。     

严重骨量不足的上颌窦底提升同期种植体植入

牙种植患者上颌或下颌牙槽嵴足够的骨量是施行牙种植修复的前提,但上颌牙缺失后常出现上颌窦腔的扩大气化,导致牙槽嵴高度不足。这常需要进行上颌窦底提升手术以恢复植牙所需的骨高度。常规的治疗方案中,在牙槽嵴剩余骨量小于3mm时,需先进行骨增量手术,待新骨生成后,再作二期种植体植入手术。这种治疗方案由于需两次手术,增加病员的负担及复诊次数,需要较长的治疗疗程。     

Five-year evaluation of implants in the resorbed maxilla

The survival of implants placed in the resorbed maxillae was investigated. Both edentulous and partially edentulous patients were evaluated including those who underwent 'sinus lift' procedures. The group of patients with a sinus floor augmentation showed a five-year cumulative survival rate varying between 100% for fixed bridges on implants in the partially edentulous maxillae and 75.6% for implants under overdentures placed in severely resorbed edentulous maxillae. It is concluded that placement of implants in the augmented sinus-floor is justified, if the patient is well informed. The procedure can provide a good solution for the prosthetic problems of patients with a resorbed maxilla.     

Success of implants in the moderately resorbed edentate maxilla

In applications of implants in the moderately resorbed maxilla factors such as bone quantity and the loading of the bone are of importance for the prognosis. Long-term studies have shown that for the maxilla the results were less good than for the mandible. The main reason for this is the condition of the bone, especially reduced bone quantity together with a thin corticalis an low bone density. Beside these factors there are also the general negative factors such as rheumatoid arthritis, osteoporosis, smoking and radiotherapy. The prognosis of implant supported prostheses is not primarily determined by the number of implants, but by the condition of the bone and to some extent by the splinting effect of the implants.     

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.     

Sinus augmentation for single-tooth replacement in the posterior maxilla: a 3-year follow-up clinical report

A technique for single-tooth sinus lift and simultaneous implant placement in the posterior maxilla is presented. Ten hydroxyapatite-coated cylindric implants, 13 to 15 mm in length, were placed together with a composite bone graft of demineralized freeze-dried bone allograft and autogenous bone in 10 adults. Surgical technique and anatomic considerations are discussed. Follow-up of 3 years showed successful function and no cervical bone loss in all patients.     

A prosthodontic concept using implants in the resorbed edentulous maxilla

For the treatment of the atrophic edentulous maxilla implant supported overdentures provide the opportunity to obtain proper lip support, speech and cleanliness. A superstructure with high rigidity is needed for an optimal distribution of occlusal loading, to ensure good prognosis for implant survival. A prosthodontic concept using a hybrid construction meets these criteria. It consists of a cast and precision-milled mesostructure fixed to the implants, over which that a removable cast prosthodontic device is placed to which the teeth are attached. It is essential to follow a strict treatment protocol to obtain a good and predictable result.     

Osteoplastic reconstruction of severely resorbed maxilla by stack plasty: combining sinus augmentation with lateral and vertical onlay bone grafting

Progressive loss of the alveolus with aging leads to defects in the buccolingual and vertical dimensions. Maxillomandibular spatial discrepancies and deficits in sagittal facial projection develop at the same time as deficiencies of the periodontal unit, alveolar bone, and attached gingiva increase, depending on the extent of the atrophy. To restore the anatomy, a sinus lift should be combined with lateral and vertical bony augmentation in an osteoplastic procedure. To achieve this, “block over block” replacement with bone from the iliac crest allows precise functional and aesthetic restoration of the alveolus and the nasomaxillary region by combining inlay, interpositional, and onlay grafting. To our knowledge, preprosthetic osteoplastic reconstruction with stacked bone grafts has not previously been documented with a large number of patients. We report the results of this procedure in 62 patients with severe maxillary atrophy.     

Complications of the surgical treatment of the severely resorbed edentulous maxilla

Complications during reconstructive surgery for placement of endosseous implants in the severely resorbed maxilla are described, based on recent literature. Detailed long term follow-up studies on complications are lacking. Clinical experience has shown that this type of surgery is prone to complications. These complications must be taken into account when indicating and planning this type of surgery.     

Augmentation of the posterior maxilla by way of sinus grafting procedures: recent research and clinical observations

This article presents some of the clinical problems with bony augmentation of the posterior maxilla using sinus lift procedures to effect alveolar bone reconstruction. The antral membrane and the bone of the antral floor have regenerative potential commensurate with other bone of the maxilla and mandible. The stem cells involved in the periosteum of the sinus floor and the mucoperiosteum of the oral cavity covering the osteotomy opening combine to form a very receptive site for grafting and surgical procedures. Distraction osteogenesis, with and without bone inductor cytokines, will play a prominent part in sinus floor augmentation and in posterior maxillary alveolar bone grafting in the future.     

Comparing the influence of crestal cortical bone and sinus floor cortical bone in posterior maxilla bi-cortical dental implantation: A three-dimensional finite element analysis

Abstract

Objective. This study aimed to compare the influence of alveolar ridge cortical bone and sinus floor cortical bone in sinus areabi-cortical dental implantation by means of 3D finite element analysis. Materials and methods. Three-dimensional finite element (FE) models in a posterior maxillary region with sinus membrane and the same height of alveolar ridge of 10 mm were generated according to the anatomical data of the sinus area. They were either with fixed thickness of crestal cortical bone and variable thickness of sinus floor cortical bone or vice versa. Ten models were assumed to be under immediate loading or conventional loading. The standard implant model based on the Nobel Biocare implant system was created via computer-aided design software. All materials were assumed to be isotropic and linearly elastic. An inclined force of 129 N was applied. Results. Von Mises stress mainly concentrated on the surface of crestal cortical bone around the implant neck. For all the models, both the axial and buccolingual resonance frequencies of conventional loading were higher than those of immediate loading; however, the difference is less than 5%. Conclusion. The results showed that bi-cortical implant in sinus area increased the stability of the implant, especially for immediately loading implantation. The thickness of both crestal cortical bone and sinus floor cortical bone influenced implant micromotion and stress distribution; however, crestal cortical bone may be more important than sinus floor cortical bone.     

The zygomaticus implant protocol in the treatment of the severely resorbed maxilla.

The zygomaticus dental implant, designed by NobelBiocare, was developed primarily for the treatment of the severely resorbed maxilla. Br?nemark has reported an overall success rate of 97.6% with the placement of over 200 zygomatic implants during the period 1989 to 2001. There are well-defined characteristics within the patient's resorbed skeletal frame which guide the surgical placement of the zygomatic implant, thus determining whether the surgeon should use an implant with a 45 degrees or 55 degrees angulated head. This allows implant-supported restoration of the resorbed maxilla with a fixed cross arch prosthesis in the maxilla without a bone graft to the posterior maxilla. The use of a modified head angulation of 55 degrees, with implant placement as close to the crest of the edentulous ridge as possible, allows restorative clinicians to achieve an ideal restorative position in the posterior maxilla. The use of a zygomatic implant with a 55 degrees head reduces the buccal cantilever by 20%.     

Use of the multi-cup denture for a severely resorbed maxilla: a clinical report

Obtaining a satisfactory outcome for a patient with a severely resorbed maxilla can be extremely challenging. This clinical report describes the treatment of a patient with a history of multiple implant failures in the maxilla. A conventional upper complete denture had poor retention and so did not fulfil the patient's needs. Further surgery was not considered appropriate. A new upper complete denture was made with a fitting surface covered in multiple suction cups to attempt to improve the retention without surgery and resulted in a pleasing outcome for both the patient and authors.     

Reconstruction of the resorbed edentulous maxilla using autogenous rib grafts and osseointegrated implants

14 patients with severely resorbed edentulous maxillae underwent reconstruction by the use of autogenous rib graft on‐lays and osseointegrated Brånemark System® implants in a one‐stage procedure. 75 implants were installed. 16 (21.3%) failed to osseointegrate at the abutment connection. After a mean observation period of 5.2 years, 55 (73.3%) of the original implants were osseointegrated. 10 supplementary implants were inserted in 3 patients. At the end of the observation periods, 2 patients had overdentures and 12 had fixed prostheses. The mean marginal bone loss was 2.13mm (SD 0.47mm) the 1st year after grafting, and 2.92mm (SD 1.27mm) at the end of the follow‐up periods. Long‐term follow‐up did not show any persistent donor site discomfort. The results indicate that this technique is a conceivable alternative for patients with severe maxillary resorption.     

Alveolar distraction osteogenesis and implant placement in a severely resorbed maxilla: a clinical report

Atrophy of maxillary alveolar bone can result in severe defects of the alveolar ridge. Such defects can make it difficult to achieve esthetic and functional restorations. This clinical report describes the use of alveolar distraction osteogenesis to promote the formation of new bone and soft tissue in a large, severely resorbed segment of maxillary alveolus.     

Connection designs of three different implant systems in the resorbed edentulous maxilla: a case report

This report presents the mixed use of three different system implants for an implant-supported fixed bridge in a resorbed maxilla. Two of six implants that had been placed were lost. New implants were combined with the remaining implants that had been placed by the previous dentists in 1992 and 1997. The three implant systems consisted of the following: one incorporated an intramobile element into an implant device, and the other two were whole titanium screw-type implants (one with a machined surface and the other with a plasma-sprayed surface). This clinical report describes the connection designs of these different system implants to the fixed bridge and lists the complications that followed.     

Reconstruction of the severely resorbed maxilla with bone grafting and osseointegrated implants: a preliminary report

This article describes a surgical procedure for rehabilitation of the severely atrophic maxillary alveolar ridge by bone grafting to the maxillary sinus and nasal floor followed by installation of implants in the grafted regions at a second operation. Five treated cases are presented. Further data are considered necessary to evaluate the procedure before it can be recommended for routine use.     

Simplifying management of the posterior maxilla using short, porous-surfaced dental implants and simultaneous indirect sinus elevation

This article describes the use of short, porous-surfaced root-form dental implants and an indirect, simultaneous, osteotome-mediated sinus elevation procedure to restore the posterior maxilla when as little as 3 mm of bone remain below the sinus floor. Results with 16 patients who are part of an ongoing prospective clinical trial using the Endopore implant show 100% success (using established criteria) with a mean implant length of 6.9 mm and a mean functional time of 11.1 months. This treatment approach greatly simplifies the management of the posterior maxilla with minimal bone height below the sinus floor.