Use of osseointegrated implants in the restoration of head and neck defects

Osseointegrated implants can be applied to facilitate retention, stability, and support for facial and intraoral prostheses used to restore head and neck defects. At the University of California, Los Angeles, Maxillofacial Prosthetics Clinic, retrospective studies have indicated that in nonirradiated maxillectomy patients, implant survival rates are 82.6 percent. In mandibles reconstructed with fibula free flaps, survival rates are 94.6 percent. Similarly, high implant survival rates have been observed for most sites used to support facial prostheses. Cumulative six-year survival rates for auricular sites exceed 95 percent and for floor of nose sites, success rates exceed 87 percent. However, survival rates are low (53 percent) for implants placed in the frontal bone for retention of orbital prostheses and even lower for irradiated bone sites ranging from 63 percent in the maxilla to 27 percent in the orbit.     

The epithelial interface with osseointegrated implants

The development of osseointegration has generated interest in the field of intraoral and maxillofacial implantology. There is well documented evidence of a high level of success in achieving osseointegration, using titanium and alumina-ceramic implant materials. Long term retention of intraoral implants appears in part, to be dependent upon the integrity of the epithelium/implant interface. This paper presents the design features of two commercially available systems Intra-Mobile-Zylinder (IMZ) and Tubingen (Frialit), which represent titanium and alumina-ceramic implants respectively, and reviews current knowledge of the nature of the epithelial junction to implant materials and the bacterial flora associated with successful and failing implants. Implant failure may be caused by a site specific infection with a similar ecosystem and bacterial flora to that found in periodontal disease. Care in patient selection and maintenance of a healthy epithelial junction are essential for the long term function of osseointegrated implants.     

The sequential failure of osseointegrated submerged implants

This report presents a case of sequential failure of nonrestored implants that were osseointegrated and submerged for 3 years. The suspected causes of failure were investigated and analyzed. These included anatomic, physiologic, traumatic, and pathogenic factors. The findings of this report compliment other literature and contribute to the comprehensive classification of implant failure based on osseointegration criteria.     

Extraoral application of osseointegrated implants

The use of osseointegrated implants to provide support for craniofacial prostheses has provided the clinician with another approach to the treatment of complex craniofacial reconstructive problems. The surgical technique is reviewed and the Mayo Clinic experience is presented.     

Optimal placement of osseointegrated implants

In summary, there is no substitute for thorough diagnosis, treatment planning, and meticulous surgical and prosthetic treatment. Proper utilization of surgical and radiographic correction-stents is one of the important aspects of the presurgical phase. The stents facilitate the accurate placement of implants in optimal positions where sufficient bone is present. In cases with insufficient bone, the stents may help in making a strategic alteration of the chosen implant site.     

Clinical complications of osseointegrated implants

STATEMENT OF PROBLEM: There is no comprehensive review of the literature that identifies the complications reported in clinical dental implant studies. PURPOSE: This article attempted to determine the types of complications that have been reported and to provide data regarding their frequency. METHODS: All available clinical studies from 1981 to 1997, published in English or with English abstract, that presented success/failure data regarding implant treatment were evaluated to determine the types of reported complications and to quantify implant loss as it relates to type of prosthesis, arch, time, implant length, and bone quality. RESULTS: Greater implant loss occurred with overdentures than with other types of prostheses. There was greater loss in the maxilla than mandible with fixed complete dentures and overdentures, whereas little arch difference was noted with fixed partial dentures. Implant loss increased with short implants and poor bone quality. The time of implant loss (preprosthetic vs postprosthetic) varied with type of prosthesis. Surgical complications included neurosensory disturbance, hematoma, mandibular fracture, hemorrhage, and tooth devitalization. Initial and long-term marginal bone changes were identified. Peri-implant soft tissue complications included dehiscence, fistulas, and gingival inflammation/proliferation. Mechanical complications were screw loosening/fracture, implant fractures, framework, resin base and veneering material fractures, opposing prosthesis fractures, and overdenture mechanical retention problems. Some studies also presented phonetic and esthetic complications. CONCLUSIONS: Although the literature presents considerable information on implant complications, variations in study design and reporting procedures limited the available data and therefore precluded proper analysis of certain complications.     

The rehabilitation of oral defects by osseointegrated implants

Abstract. So far, preprosthetic surgery for oral defects improved prosthetic retention problems for only a limited amount of time and led to many side-effects. The alternative offered by the osseointegration technique developed by P.–I. Brånemark changed the concept of preprosthetic surgery dramatically. By means of a few permucosal titanium screws, bridges or overdentures can be retained even in cases of advanced jaw bone resorption. When the latter is extreme, an autologous free bone graft fixed by means of self-tapping titanium implants can offer the necessary support for sometimes elaborate prosthetic reconstructions. The marginal bone loss around Brånemark implants is very limited after a 1st year of bone remodelling, even when an autologous transplant has been used.     

Clinical applications of osseointegrated implants

In the described seven case reports, the authors have demonstrated a number of varied applications of osseointegrated implant techniques including both removable and fixed prostheses. All patients had expressed dissatisfaction with previous prosthetic efforts to restore a satisfactory level of mastication or a desire to do away with removable oral prostheses. A high level of patient satisfaction was achieved through the application of implant techniques in these patients. Proper treatment planning must now include a consideration of implant dentistry as well as the previously available conventional alternatives for our edentulous and partially edentulous patients.     

Biological success in osseointegrated implants

Long term research results initiated by Dr. P. I. Branemark in 1965 and before, had widely demonstrated that with an adequate biomaterial, a phenomenon of biological acceptance from maxillary bone occurs, configurating a real bone healing, obtaining an intimate bonding between this alive tissue and the implant, which will last under function. Nevertheless, for this bio-physiological step happens and remain, there are many necessary factors named biological and biomechanical principles, and they command and are the responsibles of the osseointegration success.     

The role of osseointegrated implants in esthetic dentistry

During the past 5 years, tremendous advancements have been made in the application of the principles of osseointegration to esthetic dentistry. Long-term predictability, combined with time-honored esthetic principles, can now greatly benefit patients previously burdened by removable dental appliances.     

The three-dimensional finite element analysis of fixed bridge restoration supported by the combination of teeth and osseointegrated implants

This study investigated the designs of osseointegrated prostheses in cases of free-end partial edentulism using comparative stress interpreted with the three-dimensional finite element method. Three free-end fixed osseointegrated prostheses models with various connection designs (i.e., rigidly connected to an abutment tooth and an implant, rigidly connected to an implant and two abutment teeth, and rigidly connected to an implant and three abutment teeth) were studied. The stress values of the three models loaded with vertical, buccolingual, and linguobuccal directions at 30 degrees angled to vertical axis forces were analyzed. When the fixed partial denture was connected to the three natural abutment teeth and an implant, the lowest levels of stress in the bone were noted.     

The periodontal ligament of teeth connected to osseointegrated implants

Abstract The aim of the present investigation was to analyze the periodontal tissues at immobilized teeth connected to osseointegrated implants. 10, 1-year old beagle dogs, were used. Bilaterally, the mandibular 2nd (₂P₂) and 3rd pre-molars (₃P₃) and 1st molars (₁M₁) were extracted. 2 titanium fixtures were installed in the edentulous segment of the right side of the mandible, one about 10 mm mesial and the other about 10 mm distal to 4P (test tooth). 3 months later, abutment connection was performed and healing allowed for one month. The dogs were randomly divided into 2 groups of 5 each, group A and group B. In group A, a fixed gold splint, rigidly connecting the tooth and the 2 implants, was installed on day 0 and ₄P was hereby immobilized. The controlateral 4th premolar (P4) served as the non-splinted control tooth. Plaque control measures continued until the end of the experiment (day 180). In group B, plaque control measures were abandoned 1 month after abutment connection and a 4-month period of experimental periodontal tissue breakdown was initiated. This was accomplished by placing cotton floss ligatures submarginally around ₄P and P₄. At the end of this 4-month period, the ligatures were removed, and an apically positioned flap procedure was performed. Healing was allowed for another 2 months. Plaque control measures were re-established and continued throughout the experiment. A given day was termed day 0 and ₄P was rigidly connected to the adjacent implants in the manner described for group A. At the end of a subsequent 6-month period, radiographs of ₄P and P₄ were taken and biopsies harvested from all the dogs. The results of measurements, made in histological sections, revealed that the splinting of mandibular premolars to osseointegrated implants failed to induce marked alterations (qualitative and quantitative) in the gingiva and periodontal tissues of the immobilized teeth. These findings offer a biological explanation for the fact that a fixed bridge, utilizing both teeth and implants as abutments, seems to function well in the rehabilitation of partially edentulous patients.     

Psychological impact of osseointegrated dental implants

This longitudinal study of 39 patients who underwent treatment involving osseointegrated implants examined problems in oral and psychosocial functioning, expectations and experiences of difficulties with surgery, satisfaction with surgery, body image, neuroticism, self-concept, and extroversion. Patients completed six questionnaires from before phase 1 surgery to the final recall appointment for the new prosthesis (12 to 18 months after phase 1 surgery). The most common problems reported before treatment were those associated with eating; esthetics was less of a concern. Significant improvements in all problem areas were observed immediately after phase 2 surgery. Expectations of surgery-related problems were generally consistent with experiences immediately after phase 1 surgery, but more negative than experiences following phase 2 surgery. Body image before treatment was most negative vis-à-vis teeth. Significant improvements were found not only regarding teeth, but also on facial, mouth, and even overall body image. Satisfaction scores were generally high, but showed continued improvements through the final assessment. The only group experiencing negative outcomes consisted of patients scoring high on neuroticism.     

放射线对HA涂层种植体骨结合及周围骨组织影响的实验研究

目的:观察放射线对金属种植体骨结合及周围骨组织的影响。方法:成年杂种狗14只 ,随机分为7组 ,每组2只 ,所有动物均在下颌骨下缘植入羟基磷灰石 (HA)钛种植体 ,第1组为对照组不做放射 ,另外6组按两因素析因设计在种植后进行放射 ,其中剂量因素设20GY及30GY两个水平 ,时间因素设植入种植体后4周、8周、12周施行放射3个水平 ,共6组进行实验。采用X光片及组织学方法观察种植体骨结合及周围骨组织情况。结果:无论是剂量为20GY或30GY ,种植后8周和12周进行放射的种植体骨结合率均高于种植后4周进行放射组 (P<0.01) ,而种植后8周和12周进行比较 ,两者间无显著性差别 (P>0.05)。结论:骨结合受放射线的影响主要在骨结合未完全形成时 ,放射线可能使骨结合的形成处于静止状态 ,而对已形成的骨结合则影响不大。     

种植体骨结合稳定性测量及相关因素分析

目的:测量种植体骨结合稳定系数(ISQ),分析影响稳定性的相关因素。方法:对39名种植术后3~6个月后要进行修复的患者(男25,女14),102枚ITI种植体骨结合稳定性进行共振频率(RFA)测量。结果:ITI种植体骨结合ISQ为:76.29±5.25;ITI种植体稳定性主要受种植体骨质影响,密质骨(I、II)种植体稳定性(78.73±3.5)要高于松质骨(III、IV)的稳定性(74.27±5.63)(P<0.05);上颌与下颌的种植体稳定性差异不明显(P>0.05),上颌后牙区稳定性(77.57)要高于前牙区(73.65,P<0.05),下颌前后牙区无明显差别(P>0.05);不同长度不同直径种植体之间稳定性无明显差异(P>0.05)。结论:种植体稳定性与种植体周围骨质关系密切,种植体ISQ可以协助判断上部结构的修复时机,缩短种植修复的周期。     

Microbiota of successful osseointegrated dental implants

BACKGROUND: The long-term survival of dental implants depends, in part, on control of bacterial infection in the peri-implant region. Periodontal pathogens colonized implants symptomatic through infection, whereas the microbiota of successful implants was similar to that of periodontal health. This study examined the impact on the peri-implant microbiota of crown restorations; implant type; length of time of loading; history of implant or periodontal infections; and whether implants replaced single or multiple teeth. It was of particular interest to evaluate implant colonization by species in a newly described red complex of periodontal pathogens, Porphyromonas gingivalis and Bacteroides forsythus. METHODS: This study sampled 43 partially edentulous subjects with successfully osseointegrated titanium root-form dental implants. Eighty-one (81) non-submerged and 20 submerged asymptomatic implants, 83 crowned, and 36 uncrowned teeth were sampled from peri-implant or subgingival sites. The microbiota of samples was evaluated using whole genomic DNA probes in a checkerboard assay to 23 subgingival species. RESULTS: Implants were colonized principally by oral streptococci, capnocytophagae, Veillonella parvula, Peptostreptococcus micros, and Fusobacterium nucleatum. The periodontal species, P. gingivalis, B. forsythus, Prevotella intermedia, Prevotella nigrescens, and Campylobacter rectus were detected in a few subjects. The microbiota around crowned implants and crowned teeth was similar. Streptococcus oralis, P. intermedia, and Selenomonas noxia were elevated in samples from uncrowned teeth compared to crowned teeth and implants. Microbial complexity increased as loading time increased, but colonization by periodontal pathogens, including red complex species, was higher in subjects with previous periodontal disease. No differences were observed in the microbiota of 1- and 2-stage implants, or between implants supporting single or multiple restorations. CONCLUSIONS: While presence of crowns had only a minor impact on the peri-implant microbiota, microbial changes were observed the longer the implants had been in function and in those patients with a history of periodontal or peri-implant infections. A history of periodontitis had a greater impact on the peri-implant microbiota than implant loading time. The major influence on the peri-implant microbiota was, however, the microbiota on remaining teeth. P. gingivalis and B. forsythus, red complex periodontal pathogens, colonized several implants, although all implants were successfully osseointegrated.