Maintenance and treatment of the ailing and failing implant

Due to the pathologic nature of oral bacteria, the partially edentulous implant patient is at a greater risk than the fully edentulous. Peri-implantitis and/or retrograde peri-implantitis can result in ultimate loss of the implant fixture. It is important that the implant dentist understand the difference between the ailing implant, the failing implant, and the failed implant. This article discusses the pathologic diseases that affect dental implants and how to treat the "infected" implant (degranulation and detoxification) for titanium and hydroxylapatite-coated implants. Implant maintenance, including hand or motorized brushes, flosses, and oral rinses (chlorhexidine, 0.2%) will also be presented.     

Available bone is the foremost criterion in the insertion of endosteal implants

The foremost criterion in the insertion of endosteal implants is bone availability. Implant dentists should consider first the amount of available bone of the edentulous ridge where the endosteal implant will be inserted. A common error and cause of many implant failures is the dentist's use of an implant modality which is not indicated for the density and morphology of the available bone in the edentulous ridge. Implant modality/system is not the primary criterion in the insertion of endosteal implants. Before the dentist inserts an endosteal implant, he should gauge or measure the amount of bone where the implant is intended to be placed. It should be measured in width, height, length, trajectory, and implant-crown ratio. After recording the measurements of the available bone, these should be placed in different categories to serve as guides in implant selection. If there is not enough bone for the endosteal implant, bone modification should be performed. This can be done either by osteoplasty or ridge augmentation with the use of bone grafting materials. Aside from the amount of available bone in the edentulous ridge, another very, very important thing that should be considered is the quality or its density. Any biocompatible implant demonstrates some osseointegrated surfaces depending upon the bone type into which it is placed and the loads placed upon it. Implant body must exhibit a macrogeometry suitable for acceptable levels of force transfer to the surrounding tissues as well as for implantation into a bony site of a particular anatomic size.     

Managing malrelated arches and limited vertical space for implant-supported overdentures: a case report

Advancements in implant therapy have expanded the prosthetic options available to treat edentulous patients. The dental professional must be able to accurately diagnose the status of the intraoral environmental in order to provide the patient with appropriate treatment and a suitable restorative result. Skeletal relationships, arch malalignment, implant angulation, and ridge morphology must be evaluated during initial treatment planning and incorporated into the definitive prosthetic result. This case report demonstrates the application of an implant-supported prosthesis to address the various complications presented in the treatment of edentulous patients.     

Clinical evaluations of a porous-surfaced endosseous implant system

Clinical evaluations of a new porous-surfaced implant concept (Endopore) in a large population of fully and partially edentulous patients are reported, and a technique of spreading buccal and lingual plates with osteotomes to place these implants in proximity to the sinus of the posterior maxilla is described. Three-dimensional, interconnecting pores on this implant's bone interface surface give a great surface area for bone engagement. When the maxilla is prepared by this spreading procedure, these implants can be successfully placed in areas having limited available bone. Our success rates are 97.0% for implants stabilizing a mandibular overdenture and 94.8% for implants placed in partially edentulous patients. Many times, sinus lift or other augmentation procedures can be avoided in the maxilla and mandible, allowing for less patient morbidity and for an implant reconstruction that is more affordable for the patient.     

Comparison of position repeatability of a human operator and an industrial manipulating robot

STATEMENT OF PROBLEM: Implant-supported restorations in the partially edentulous jaw have been performed at the Mayo Clinic for more than 10 years. Clinical performance of the implants and the prostheses should be reported to ensure effectiveness of this procedure. PURPOSE: This retrospective study described results for implant survival, implant fracture rate, prosthetic complications, and design changes that may impact these results. MATERIAL AND METHODS: A retrospective chart review was conducted of all registered implant patients in a large multispecialty medical center. Patients with a partially edentulous jaw who had received endosseous implants to support and retain dental prostheses were included in this review. Implant survival and fracture, prosthetic complications, and demographic data were recorded and analyzed through Kaplan-Meier methods. RESULTS: A total of 1170 implants were placed in four anatomic locations: anterior maxilla, posterior maxilla, anterior mandible, or posterior mandible. Location of implants was shown to have no effect on implant survival (p = 0.7398), implant fracture rates (p = 0.2385), screw loosening (p = 0.8253), or screw fracture (p = 0.2737). Development of new restorative components has resulted in significantly better rates of implant survival without fracture (p = 0.0054), screw function without loosening (p < 0.0001) and screw function without fracture (p = 0.0013). Implant survival seems to have been improved with the new components (p = 0.0513). CONCLUSIONS: Implant survival in this study was independent of anatomic location of implants. Virtually all clinical performance factors were improved by design changes in implant restorative components that were brought to market in early 1991.     

In vitro yields and in vivo activity of a polyhedrin gene-deleted and wild strain of the nucleopolyhedrosis virus of Autographa californica

A range of biomaterials are used in rendering prosthodontic treatment for the completely edentulous patient. This article reviews the biomaterials considerations in the use of metals and metal alloys, ceramics and carbons, and synthetic materials for implant therapy. It also discusses implant material selection, biomaterial aspects of bioadhesion, and osseointegration and hygiene-related biomaterial factors.     

Biological factors contributing to failures of osseointegrated oral implants. (I). Success criteria and epidemiology

The aim of this review was to offer a critical evaluation of the literature and to provide the clinician with scientifically-based diagnostic criteria for monitoring the implant condition. The review presents the current opinions on definitions of osseointegration and implant failure. Further, distinctions between failed and failing implants are discussed together with the presently used parameters to assess the implant status. Radiographic examinations together with implant mobility tests seem to be the most reliable parameters in the assessment of the prognosis for osseointegrated implants. On the basis of 73 published articles, the rates of early and late failures of Br?nemark implants, used in various anatomical locations and clinical situations, were analyzed using a metanalytic approach. Biologically related implant failures calculated on a sample of 2,812 implants were relatively rare: 7.7% over a 5-year period (bone graft excluded). The predictability of implant treatment was remarkable, particularly for partially edentulous patients, who showed failure rates about half those of totally edentulous subjects. Our analysis also confirmed (for both early and late failures) the general trend of maxillas, having almost 3 times more implant losses than mandibles, with the exception of the partially edentulous situation which displayed similar failure rates both in upper and lower jaws. Surgical trauma together with anatomical conditions are believed to be the most important etiological factors for early implant losses (3.60% of 16,935 implants). The low prevalence of failures attributable to peri-implantitis found in the literature together with the fact that, in general, partially edentulous patients have less resorbed jaws, speak in favour of jaw volume, bone quality, and overload as the three major determinants for late implant failures in the Br?nemark system. Conversely, the ITI system seemed to be characterized by a higher prevalence of losses due to peri-implantitis. These differences may be attributed to the different implant designs and surface characteristics. On the basis of the published literature, there appears to be a number of scientific issues which are yet not fully understood. Therefore, it is concluded that further clinical follow-up and retrieval studies are required in order to achieve a better understanding of the mechanisms for failure of osseointegrated implants.     

Treatment planning and surgical considerations for placement of wide-body implants

Partially edentulous implant treatment has evolved from using a standard diameter fixture for every tooth site to selection of the implant diameter according to the surgical demands, space available, and the dimension of the final prosthetic tooth. The advantages are functional, improved emergence profiles for esthetics, and optimal contours for oral hygiene maintenance. This article reviews presurgical treatment planning for wide-diameter implants.     

Educating a patient with dental implants

A functional dentition can be restored for edentulous and partially edentulous patients through the placement of dental implants. Dental assistants have a significant role in the education of implant patients so that meticulous oral self-care can be accomplished. Only through the combined team efforts of the dental office staff and patients themselves will the continued success of dental implantology be insured.     

Failure of oral implants: aetiology, symptoms and influencing factors

The use of oral implants opened a wide range of prosthetic treatment possibilities in edentulous patients. Although the reported success rates of oral implants are high, failures do occur. This paper reviews the current knowledge about the aetiology, the signs and symptoms and the possible influencing factors of implant failure. Possible causes of implant failure are thought to be infection of the periimplant tissues, occlusal overload, or a combination of both. Nevertheless, pinpointing one of these as the aetiological factor in a particular case is difficult and should be handled reluctantly. Although the cause might seem obvious, influencing factors could play a role as well. Gaining insight into these processes might stimulate the adoption of preventive action and therefore increase the predictability of the treatment outcome with oral implants.     

Implant placement without flaps: a single-stage surgical protocol--Part 1

Osseointegrated implants have been demonstrated to be predictable, efficacious means of restoring aesthetics and long-term function to edentulous patients. Although the surgical and placement protocols for the use of implant therapy have continued to evolve, specific criteria must be addressed when utilizing this modality. The objective of this article is to describe the requisites for proper implant placement and demonstrate the use of a novel surgical protocol to insert implant fixtures in selected edentulous sites with a mucosal tissue punch rather than a conventional flap elevation procedure.     

PST, the essential surgical template

The anticipated prosthesis now dictates the placement and angulation of the implant, thereby improving the function and the aesthetics of the final result. To establish a logical continuity between the surgical phases and the planned prosthesis, it is essential to use a transfer device. The restorative clinician can request a precise position and orientation of each implant with this communication tool. However, it is difficult to use a conventional surgical template following the soft tissue reflection and during preparation of implant osteotomy. The proper positioning of each implant is difficult to achieve, especially on a completely edentulous maxilla where restorations require even more ideal implant placement.     

Implants in the partially edentulous patient: restorative considerations

Restorative considerations are critical to the long-term success of fixed implant-supported prostheses, especially in the posterior quadrants of the partially edentulous patient. The parafunctional habit of bruxism must be identified and addressed. The restoration should dictate implant placement. Control of forces directed upon the prosthesis and implants is critical to long-term success. Anatomic limitations to implant placement and surgical procedures to correct these deficiencies must be considered for their impact on the prosthetic restoration. Nonaxial forces or bending moments should be minimized by the use of an adequate number, position and alignment of implants; by control of the occlusion; and by design of the prosthesis. The patient must understand the risks, limitations, costs and time commitments of implant restorations prior to treatment.     

Guided tissue regeneration without a stage 2 surgical procedure

In the two cases described, the problems of insufficient bone and insufficient soft tissue in the edentulous ridge were addressed concurrently. Freeze-dried demineralized bone was used to fill the osseous defect. Freeze-dried fascia lata was used to prevent epithelial migration into the defect, act as a barrier, and eliminate a second surgery for membrane removal. This regeneration procedure can provide increased alveolar bone for better implant placement and esthetics.     

Replacing posterior teeth with freestanding implants: four-year prosthodontic results of a prospective study

This article presents prospective four-year prosthetic results of the placement of 432 posterior freestanding, conventionally cemented prosthetic tooth implants in posterior edentulous spaces using the Bicon Dental Implants system (Bicon Dental Implants). Over four years, 0.74 percent of the abutments loosened, 0.5 percent of the abutments fractured, and 2.47 percent of the crowns experienced porcelain fracture, (all porcelain fractures occurred at time of placement). This low rate of problems appears to make free-standing single-tooth implant restorations a reliable solution to treating posterior edentulism.     

Follow up and maintenance of implant supported prostheses: a comparison of 20 complete mandibular overdentures and 20 complete mandibular fixed cantilever prostheses

Two independently selected groups of 20 patients who were edentulous in te mandible, were followed up on a regular basis over a 5-year period following restoration with a lower implant stabilised prosthesis and conventional upper denture. Significantly more treatment was required by those who received complete mandibular overdentures than those provided with complete fixed mandibular prostheses. In addition to adjustment for the relief of denture trauma to the mucosa, more mechanical problems arose with overdenture implant prostheses.     

Biomechanical advantages of wide-diameter implants

In implant cases in which bone quantity and interdental space are sufficient, wide-diameter implants may be preferable to standard-size implants in restoring the partially edentulous patient. Although wide-diameter implants are often considered for their esthetic possibilities, they can also offer important biomechanical advantages, particularly in reducing the magnitude of stress delivered to various parts of the implant and in improving stability. In this article, standard 3.7-mm- and wide 4.7-mm-diameter implants are compared and discussed.     

Load factor control for implants in the posterior partially edentulous segment

There are inherent biomechanical differences in the implant treatment of completely edentulous arches and posterior partially edentulous segments. The partial prosthesis does not benefit from cross-arch stabilization and is, therefore, more susceptible to bending loads. Because of the difference in mobility between teeth and implants, implants may carry a major share of load when mixed with teeth in the same quadrant. However, the frequency of implant overload in posterior partial restorations is low, and, with appropriate treatment planning, overload in these situations is almost always preventable. A checklist procedure is proposed to help the clinician enumerate and evaluate deleterious load factors. By screening patients for such factors in advance, the clinician may identify and avoid potential overload situations when conceiving and fabricating implant-supported posterior partial prostheses. A second checklist, for use at follow-up appointments, lists alarm factors that serve as an early warning of overload once the prosthesis is in place.     

Optimizing multiple individual anterior implant restorations with a new generation implant-abutment system; IMZTwinPlus: a case report and treatment rationale

A 53-year-old male with a history of initial oral facial trauma causing the loss of three maxillary incisors, multiple failures of tooth-borne fixed prosthetic reconstructions, and a resultant condition of structural failure of abutment cuspids and lateral incisor was to be retreated. The case contained numerous anatomic and dimensional constraints. The patient's desire to achieve a long-term, dependable prosthetic reconstruction prompted professional consideration of incorporating implants to lend structural support in the edentulous area. An extensive review of current implant-abutment options and their single-tooth implant replacement design and treatment rationales was conducted. The IMZ Generation III (IMZTwinPlus) implant system, a nonhex system, was chosen for treatment of the case of report to optimize mechanics, biomechanics, and esthetics for multiple individual-tooth implant replacement.     

Changes in chewing patterns after implantation in the edentulous mandible

Almost all edentulous patients with implant-supported prostheses in mandibles describe an improvement in their chewing function and quality of life. This was reason to believe that an implant prosthetic treatment actually influences mandibular border movements, as well as the chewing patterns. The present study compares border movements and chewing patterns in 15 patients recorded with the Sirognathograph. The first measurements were made with existing complete dentures. After implantation and rehabilitation with a Dolder-bar and clip-to-bar overdenture, the movements were recorded again. The measurements revealed an improved guidance of the mandibular movements and larger borderline patterns following stabilization of the complete denture with the bar. This leads to more harmonic shapes in the movements and better chewing efficiency.