The International Journal of Prosthodontics, 05/1998

Purpose: Although the clinical term osseointegration describes the anchorage of endosseous implants to withstand functional loading, it provides no insight into the mechanisms of bony healing around such implants. Nevertheless, an understanding of the sequence of bone healing events around endosseous implants is believed to be critical in developing biologic design criteria for implant surfaces. Results and Discussion: This discussion paper shows that peri-implant bone healing, which results in contact osteogenesis (bone growth on the implant surface), can be addressed experimentally. The first, osteoconduction, relies on the migration of differentiating osteogenic cells to the implant surface, through a temporary connective tissue scaffold. Anchorage of this scaffold to the implant surface is a function of implant surface design. The second, de novo bone formation, results in a mineralized interfacial matrix, equivalent to that seen in cement lines in natural bone tissue, being laid down on the implant surface. Implant surface topography will determine if the interfacial bone formed is bonded to the implant. A third tissue response, that of bone remodeling, will also, at discrete sites, create a bone-implant interface comprising de novo bone formation. Conclusion: Treatment outcomes in dental implantology will be critically dependent on implant surface designs that optimize the biologic response during each of these three distinct integration mechanisms.

Purpose: To provide a review of the overall nature and properties of materials used for manufacturing of endosseous dental implants. Results and Discussion: The importance of chemical qualities of implant surfaces is highlighted; special reference is given to titanium and its oxides. The process of bioadhesion is described, and comments are made on its relation to a range of given biomechanical factors. Conclusion: In the author's opinion, based on the arguments presented, the material properties of alloplastic implant materials have a strong influence on implant retetnion and stability, and thus on an implant's capacity to achieve so-called osseointegration.

Purpose: This article reviews the current knowledge about the influence of surgical factors on implant failure in routine cases and in those where implants have been used in conjunction with bone augmentation procedures. Materials and Methods: Clinical reports published in major scientific journals served as the basis for this review. Results: With few exceptions, most clinical reports were on screw-shaped titanium implants. High failure rates are associated with poor bone quality and the use of short implants in the athrophic maxilla, irradiation, and bone-grafting procedures of the athrophic maxilla. Evidence for high long-term failure rates of press-fit cylinders was found. Moreover, limited clinical experience, lack of preoperative antibiotics, and smoking may lead to higher failure rates. Conclusion: There is a need for further research to increase the success rates in the severely resorbed maxilla. Because of a lack of proper documentation with respect to the great majority of currently used oral implant designs, the influence of different factors and their long-term results remain unknown.

Purpose: This article reviews the literature on the anatomy and the role of the implant-mucosal interface in the long-term success of oral endosseous implants. Materials and Methods: In vitro, in vivo animal, and in vivo human studies are reviewed and discussed. Results: The anatomy of the implant-mucosal interface is described. The interface shares many features with periodontal mucosa. A clinically healthy implant-mucosal interface is a routine and predictable occurrence. The validity of using traditional clinical periodontal parameters to indicate or predict changes in peri-implant marginal bone height is unproven, especially if inflamed mucosal tissues are present. Conclusion: In general, the human host response of peri-implant mucosa to long-term functional challenges if favorable.

Purpose: This article provides a critical examination of the literature on the colonization of the peri-implant environment and its impact on clinically significant infection, in the context of a comparison with the microbial etiology of periodontitis. Materials and Methods: Previous journal article bibliographies and MEDLINE searches provided comprehensive access to current literature on this topic. References that provided significant or novel advancements in knowledge were included in this review. Since it was prepared for a workshop that would examine this issue critically, this review offers provocative commentary. Results: There are many similarities in peri-implant and periodontal microbiology, both in health and in infection leading to progressive deterioration. Periodontal pockets serve as reservoirs for the colonization of implants by periodontal pathogens in partially edentulous patients. Implant design and material composition affect the colonization of implant surfaces. Infections around implants can be treated by similar strategies used for periodontitis. Investigators are beginning to adopt research designs used in periodontology to study the pathogenesis and treatment of peri-implant infections. Research in this area is impeded by the lack of surrogate variables for crestal bone resorption. Conclusion: Some implants fail as a result of infection, but the frequency of failure by infection or any other cause is unknown. This paper suggests areas where much more additional research is needed, including critical consideration of strategies that have led to the past few decades' advancements in the pathogenesis of periodontitis.

Purpose: This article reviews the literature on radiographic imaging techniques and image interpretation for dental implant treatment. Materials and Methods: MEDLINE was used to identify published peer-reviewed literature for this report. Results: Radiographic images are indispensable in the evaluati on of osseous structures when planning treatment for dental implants. Potential bone sites for implant placement can be assessed clinically by means of palpation or probing through the mucosa; however, diagnostic imaging provides the best means for indirectly measuring bone dimensions. After healing of the implant site, the application of radiology is useful to verify the amount of bon e adjacent to the implant and that the transmucosal abutments fit the implant. Upon completion of the implant prosthesis, radiology may be used to monitor initial and long-term success of implant treatment. Conclusion: Recommendations for the application of radiology over the course of treatment are made for various implant cases ranging from the overdenture to the single-tooth implant.

Purpose: This paper reviews the literature on patient-based assessments of implant therapy. Materials and Methods: A search of the literature produced 22 papers describing 19 studies. Results: Only 3 of the 19 studies were randomized controlled trials. Consequently, most have design flaws that threaten their internal validity. In addition, the measurement of patient-based outcomes was generally poor, further weakening the evidence provided by the reserach conducted tod ate. The randomized trials indicate that implants improve chewing ability and satisfaction with dentures but have not demonstrated effects with respect to the quality of life. Conclusion: Further research is needed using randomized controlled trial designs. Outcome measures need to be more carefully selected so as to reflect patients' concerns.

Purpose: This paper presents a critical review of the literature on neurosensory disturbances associated with implant surgery. Materials and Methods: The reviewed literature includes mainly retrospective implant studies and patients' surveys, as well as a few prospective psychophysical studies on senosry disorders following maxillofacial surgeries. Results: The available data suggest that injury to the peripheral branches of the trigeminal nerve and subsequent sensory disturbances are potential complications following implant surgery. Cross-sectional studies suggest that gross tactile sensation was regained in the vast majority of patients. However, data on the spatial and temporal patterns of ercovery of this and other somatic sensation such as fine tough, nociception, and temperature sense after i mplant surgery is still lacking. The prevalence of sensory disturbances depends on several factors: the site of implant placement, the type of surgical procedures adopted, the design of the studies, the sensitivity of the testing methods, the choice of the outcome measures, and the terminology used to describe sensory disturbances. Extreme variation in the reported prevalence of neurosensory disturbances (0% to 100%) suggest that these problems have not been adequately evaluated. Conclusion: Although sensory disturbances are transient in the majority of implant patients, their prfound impact on the quality of life of the subjects affected and the possibility that they may persist clearly indicate that they should be identified and evaluated through prospective studies, using validated testing protocols and outcome measures.

Purpose: This paper reviews literature on age and jaw site in relation to jawbone quantity and quality and the osseointegration of endosseous oral implants. Results and Discussion: The condition of jawbone is both age-and site-specific. However, increased age does not appear to affect the clinical potential for osseointegration or the rate of crestal bone resorption observed around oral implants. In contrast, jaw site is related significantly to osseointegration potential; mandibular sites tend to be more successful than maxillary sites. The reason for this may be that jawbone quality and quantity are often more compromised in maxillary than in mandi bular sites. However, evaluation of this relationship has been hampered by a lack of evidence to support the validity and reliability of methods used to assess jawbone condition preoperatively. Furthermore, short-term evidence suggests that high rates of implant success can be achieved in maxillary sites, even those with low trabecular density, if an adequate volume of bone exists to accommodate the implants. Although the rate of crestal bone resorption around oral implants is usually low and may not be site-specific, there is some evidence that it may be greater in sites with less preoperative resorption associated with shorter periods of edentulism. This pattern of bone loss could jeopardize long-term implant outcomes especially in younger implant patients. Another concern in young growing patients is that their prosthetic outcome may become compromised because osseointegra ted implants cannot keep pace with growth and development in surrounding structures. Conclusion: To improve our understanding of how the age- and site-specificity of jawbone condition affects oral implant outcomes, research needs to be aimed at establishing reliable and valid measures of preoperative jawbone condition, and at better documenting the effects of jawbone condition on oral implant outcomes.

Purpose: This paper aims to establish the parameters necessary to monitor successful implant placement and osseointegration. Results and Discussion: Implant stability is considered to play a major role in the success of osseointegration. Primary implant stability at placement is a mechanical phenomenon that is related to the local bone quality and quantity, the type of implant and placement technique used. Secondary implant stability is the increase in stability attributable to bone formation and remodeling at the implant/tissue interface and in the surrounding bone. Techniques for measuring implant stability and osseointegration, including the clinical measurement of cutting resistance during implant placement and removal torque following osseointegration, are discussed. Nondestructive test methods, including impact-based techniques such as the Periotest and the Dental Fine Tester, are also discussed. An alternative method, resonance frequency analysis, is described in detail. Conclusion: It is clear that stability both at placement and during function is an important criterion for the success of dental implants. Quantitative methods, including resonance frequency analysis, can yield valuable information.

Purpose: Because existing implant success criteria have not met with widespread use, consensus is needed among profess ionals working in the field as to what constitutes implant success. This article discusses implant success within the context of prosthesis success, and argues that successful use of implants cannot be judged without prosthesis consideration. Results and Discussion: A framework for evaluating clinical success of prosthodontic treatment is presented. A context for judging success by presenting related topics that that include contrasting process and outcome measures, and consideration of long-term outcomes that have a tangible meaning to the patient (ie, are patient-based), is argued for. A hierarchy of outcomes is proposed for a better understanding of the relative strengths associated with various outcomes. Emphasis is given to the concept of prosthodontic treatment being prescribed to reduce the patient-specific burden associated with the missing tooth condition. Conclusion: The challenge is to define the best applications of dental implants within the broad context of prosthodontic options through demonstrated advantages over more conventional options. A broad understanding of success from multiple outcome domains is most likely to give the truest measure for implant application within the context of possible prosthodontic options for all patients.

Purpose: Prosthodontic components for implant treatment have been developed with minimal reported scientific investigation. This paper aims to highlight a number of problems caused by this approach to the development and marketing of prosthodontic components and to suggest solutions. Conclusion: Prosthodontic components must be developed with a scientific approach that involves both laboratory and clinical testing so as to optimize treatment outcomes in the future.