The dark side of dioxygen biochemistry

The aim of this study was to evaluate the clinical function and long-term prognosis of overdentures retained by a small number of implants in the maxilla and mandible using one of two different attachment systems. Included in the study were all patients referred to specialty clinics in J?nk?ping and Link?ping, Sweden, during the treatment period who needed an overdenture and could be provided with a minimum number of two bilaterally-placed implants. Excluded were patients with bone-grafted jaws, irradiated cancer patients, heavy bruxers, and patients who had lost a fixed prosthesis because of implant losses. The patients were randomly assigned to receive one retentive system, either a round 2-mm-diameter bar with clips or ball attachments (Nobel Biocare). Eighteen overdentures were placed in maxillae and 32 in mandibles, supported by a total of 115 Br?nemark implants. Of the implants placed, 86.1% were continuously osseointegrated. The cumulative implant survival rates after 7 years of loading were 75.4% in the maxillae and 100% in the mandibles. There was no difference in implant survival rate between the attachment systems. Patients with implant losses were characterized by severely resorbed maxillary ridges and inferior bone quality, together with unfavorable loading circumstances such as short implants combined with long leverages. Complications and prosthetic adjustments were mostly resolved early and easily.     

Interpositional bone grafting technique to widen narrow maxillary ridge

A narrow edentulous alveolar ridge, less than 6 mm in the buccopalatal aspect, can prevent restoration by means of endosseous implants. A widening technique using alveolar ridge splitting and interpositional autogenous bone grafting is described. Accurate imaging of the alveolar bone shape and size was assessed with computerized tomography in a 1:1 scale. Following 6 months of healing, osseointegrated Br?nemark implants were placed in the grafted sites.     

Human herpesvirus-6 infection in liver transplant recipients: documentation of pathogenicity

In the posterior partially edentulous jaw, implants may be used to supplement existing natural dentition. Frequently, the maxillary sinuses and the mandibular nerve preclude the fabrication of freestanding implant-retained prostheses. However, if an implant and a natural abutment are combined, a fixed prosthesis can be fabricated, restoring the arch into the premolar area. The histories of three patients with attachments connecting implant-retained ceramotitanium crowns with crowns on natural abutments are described. A design for a rigid custom-made attachment for the Br?nemark system, using standard components with a machine-duplication, spark-erosion technique, is suggested.     

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.     

Clinical and microbiological status of osseointegrated implants

Peri-implantitis, an inflammatory response around implants, has a poorly defined etiology and pathogenesis. To better understand the role of specific microorganisms in this disease process, clinical and microbiological parameters were examined in 24 patients with 98 osseointegrated implants. Sites were evaluated for probing depth (PD), plaque/calculus index (PI), gingival bleeding index (GBI), mobility, and crevicular fluid flow rate (CFFR). Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia in subgingival plaque were identified by latex agglutination assays. Clinically, a statistically significant correlation (P < 0.001) was observed between probing depth and the length of time an implant was present. Mobility was also significantly greater (P < 0.001) in the maxillary than in the mandibular implants. Subgingival sites harboring one of the three microorganisms had significantly greater PD, GBI, and CFFR than non-colonized sites. Implants in partially edentulous patients more frequently were colonized with P. gingivalis/P. intermedia than edentulous patients. The incidence of these microorganisms also correlated with fixture longevity. Implants present for 3 to 4 years had a significantly greater frequency of test microorganisms than implants present for 1 to 2 years. These findings suggest that microbial pathogens associated with periodontitis occur more commonly around implants exhibiting gingival inflammation (GBI) and may contribute to peri-implantitis.     

Linkage of DFNB1 to non-syndromic neurosensory autosomal-recessive deafness in Mediterranean families

A study involving the immediate loading of Br?nemark implants in the edentulous mandibles of 10 patients is reported. The design involved the immediate loading of four widely distributed implants with a transitional fixed implant-supported prosthesis at first-stage surgery, avoiding the need for a removable prosthesis. A sufficient number of additional implants are allowed to heal in the conventional manner to provide sufficient support for a definitive fixed prosthesis even if all of the immediately loaded implants fail. Preliminary results have been favorable, with all patients functioning with a fixed implant prosthesis from the day of first-stage surgery.     

Fixation of facial and auricular prosthesis with osseous implants in cranial bone

OBJECTIVE: To evaluate the use of osseointegrated implants to fix facial and auricular prostheses. DESIGN: Retrospective. SETTING: University Hospital Groningen, the Netherlands. METHODS: Thirty patients were treated with Br?nemark implants for fixation of auricular (21 patients) and orbital (9 patients) prostheses during May 1988-December 1995. The complications during the procedure, the success rate of the implants, skin reactions around the implants and patient satisfaction were recorded. RESULTS: A total of 97 implants were placed. One implant had to be removed after the healing period because it was loose. No other implants were lost during the follow-up period (mean 36 months; range: 12-91). The skin around the implants sometimes showed a mild reaction which could be adequately treated. In most of the cases no inflammation of the skin was observed. Retention, ease of handling and wearing comfort of the facial prostheses were excellent. CONCLUSION: Fixation of facial and auricular prostheses can be improved by osseointegrated implants resulting in high patient satisfaction.     

The use of the Periotest value as the initial success criteria of an implant: 8-year report

Osseointegration is a histometric process that occurs gradually over a period of time. The load that an implant is able to bear depends upon, among other parameters, the quality of the bone-implant contact. For 8 years the damping capacity of 1,182 Br?nemark implants inserted consecutively in 315 patients was measured using the Periotest method. The following clinical observations were made: (1) a relationship was found between implants with a specific Periotest value range that, at the moment of the transepithelial connection, were considered to be clinically stable, asymptomatic, and whose radiograph image was not radiolucent; (2) a relationship was found between clinically nonintegrated implants with a different Periotest value range; (3) variations in the Periotest value were related to the type of bone in which the implant was placed; (4) a small percentage of borderline implants with a Periotest value between the osseointegrated and the nonosseointegrated Periotest values was detected; (5) the percentage of secondary failures was related to an initial Periotest value corresponding to a borderline implant; (6) the healing time of each implant was individualized in accordance with the successively obtained Periotest value; (7) the load and the design of the prosthesis were individualized; (8) early detection of failing implants before fabrication of prostheses is possible; (9) communication was improved between the surgeon and the prosthodontist; and (10) variations in Periotest value were related to bone remodeling. The sensitivity of the principal clinical test in evaluating osseointegration is discussed regarding the moment of its application. The use of Periotest values as an initial success criteria of an implant is proposed.     

The pharmacokinetics of poliosm

Functional features of type Br?nemark implants are compared with those of type IMZ implants. The problem of determining optimal stiffness characteristics of type IMZ implants has been solved by means of linear programming. The conclusion was made on considerable improvement in distribution of loads when type IMZ osseointegrated implants are used as supporting elements in the denture.     

Advanced surgical procedures: bone augmentation

Over the last ten years there has been a significant increase in the range and type of edentulous defects that can be treated using osseointegrated implants. Encouraged by the long-term success of implant reconstructions in the edentulous mandible and maxilla, and the availability of novel implant attachments, clinicians will now undertake more elaborate treatment involving the partially edentate and those with localized or generalized tissue deficiencies. This clinical trend places increasing demands on the predictability, complexity and accuracy of the surgical procedure necessary to allow a successful prosthetic reconstruction. This is especially so when potential implant sites lie in areas of high aesthetic or functional requirements.     

Implant reconstruction of the jaws and craniofacial skeleton

Full oral rehabilitation with a high degree of success is now possible with osseointegrated implants. Osseointegration is a direct connection between living bone and the titanium implant at the level of the light microscope. Osseointegrated implants are currently used to replace single teeth, support fixed bridges and stabilize full dentures. These implants can also be placed extraorally for attachment of facial prosthesis. The surgical technique used to place implants intraorally into jaws or facial skeleton is performed in two stages using a local anesthetic and/or conscious sedation. During stage I surgery, holes are placed into the jaw using a series of gradually larger diameter burs until the desired diameter and depth of the bony preparation is achieved. The implant is then placed. The implant must remain undisturbed for 4 months for osseointegration to take place. Stage II surgery is then required to remove the mucosa over the implant and place the transmucosal abutment. After 1-2 weeks of healing, the restorative dentist can take an impression and fabricate the prosthesis. On occasion, it is necessary to augment the height and width of the atrophic jaw with autogenous or allogeneic bone grafts prior to implant placement. Bone grafts are sometimes placed on the floor of the nose or the floor of the maxillary sinus. Guided tissue regeneration is a technique used to generate bone within bony defects adjacent to implants. With long-term rates of success (5 years) of 99% for implants placed in the mandible and 95% for those placed in the maxilla, reconstruction of the jaws and cranial facial skeleton with osseointegrated implants has become the treatment of choice.     

Identification and characterization of a new splicing variant of vascular endothelial growth factor: VEGF183

The purpose of this study was to determine implant survival rates by means of life table analyses for a cohort of patients not part of a prospective efficacy trial and treated by practitioners at varying experience levels. Prognostic variables associated with implant failure were identified by means of proportional hazards models and advanced statistical methods that account for patient effects. Ninety-nine consecutive patients treated from 1987 to 1991 with follow-up to 1994 were included in this retrospective study. A total of 384 dental implants (79.7% Br?nemark, 19.3% IMZ plasma-sprayed, 1% IMZ hydroxyapatite-coated) were placed and subsequently supported 108 prostheses. Survival and proportional hazards modeling were used to generate Kaplan-Meier survival curves and to identify variables associated with implant failure. Survey data analysis was used to adjust for any patient effects for variables identified as significant through the proportional hazards models. Thirty-four implants failed over the follow-up period (median follow-up time 3.6 years), resulting in an overall failure rate of 8.9%. Seventeen of 99 patients experienced an implant failure. When prosthesis type was excluded from the modeling process, survey data analysis identified posterior location and an implant width of less than 4.0 mm as being associated with implant failure (all P < .05).     

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.     

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.     

The effect of strenuous versus moderate exercise on the metabolism of proteoglycans in articular cartilage from different weight-bearing regions of the equine third carpal bone

In the present multi-center study, non-submerged ITI implants were prospectively followed to evaluate their long-term prognosis in fully and partially edentulous patients. In a total of 1003 patients, 2359 implants were consecutively inserted. Following a healing period of 3-6 months, the successfully integrated implants were restored with 393 removable and 758 fixed restorations. Subsequently, all consecutive implants were documented annually up to 8 years. At each examination, the clinical status of all implants was evaluated according to predefined criteria of success. Therefore, the data base allowed the evaluation of 8-year cumulative survival and success rates for 2359 implants. In addition, cumulative success rates were calculated for implant subgroups divided per implant type, implant length, and implant location. Furthermore, the actual 5-year survival and success rates could be determined for 488 implants. During the healing period, 13 implants did not successfully integrate, whereas 2346 implants fulfilled the predefined criteria of success. This corresponds with an early failure rate of 0.55%. During follow-up, 19 implants were classified as failures due to several reasons. In addition, 17 implants (approximately 0.8%) demonstrated at the last annual examination a suppurative periimplant infection. Including 127 drop out implants (= 5.4% drop out rate) into the calculation, the 8-year cumulative survival and success rates resulted in 96.7% and 93.3%, respectively. The analysis of implant subgroups showed slightly more favorable cumulative success rates for screw type implants (> 95%) compared to hollow-cylinder implants (91.3%), and clearly better success rates for mandibular implants (approximately 95%) when compared to maxillary implants (approximately 87%). The actual 5-year survival and success rates of 488 implants with 98.2% and 97.3%, respectively, were slightly better than the estimated 5-year cumulative survival and success rates of 2359 implants indicating that the applied life table analysis is a reliable statistical method to evaluate the long-term prognosis of dental implants. It can be concluded that non-submerged ITI implants maintain success rates well above 90% in different clinical centers for observation periods up to 8 years.     

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.     

The use of transitional implants for immediate fixed temporary prostheses in cases of implant restorations

While the original Br?nemark implant protocol has continued to evolve, the avoidance of implant loading during osseointegration remains a prerequisite with all implant systems. Immediately loaded transitional implants have recently been developed to support the fabrication of a fixed provisional prosthesis that provides implant patients with improved aesthetics and function during the osseointegration period. In this manner, osseointegration can occur free from prosthetic and transmucosal loads. This article describes the use of transitional implants and presents a classification of three different case types.     

Microscopical features in retrieved human Branemark implants: a report of 19 cases

The authors present a histologic analysis of 19 Branemark titanium implants retrieved for different causes: four implants were removed for abutment fracture, one for dental nerve dysesthesia, two for bone overheating, two for peri-implantitis, nine for mobility, one for unknown causes. In the implants removed for fracture a high bone-implant contact percentage was present (71.83 +/- 4.96%) with compact, mature bone at the interface. The picture of the failure due to bone overheating was characteristic with the presence of bone sequestra and of a gap between implant and bone filled by lymphocytes and plasma cells: many bacteria surrounded the necrotic bone and no newly regenerated bone was present. In peri-implantitis an inflammatory infiltrate was observed in the peri-implant tissues: a dense fibrous connective tissue was present around implants failed for mobility. The microscopical picture is certainly extremely important in identifying the causal determinants of an implant failure.     

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.     

Clinical assessment of olfactory dysfunction in Parkinson''s disease

The possibility of placing endosseous implants in the edentulous maxilla is frequently reduced by inadequate bone volume of the residual ridge. In totally edentulous maxillae with knife-edge conformation, insufficient thickness is frequently associated with insufficient height of the residual ridge in the posterior maxilla because of pneumatization of the maxillary sinuses. This surgical method combines grafting of the maxillary sinuses, onlay grafts on the buccal side of maxillary posterior segments, and sagittal osteotomy of the anterior maxilla with interpositional bone grafts. Five to six months after maxillary reconstruction, Br?nemark implants were placed and, after osseointegration occurred, implant-supported dental prostheses were fabricated. Three patients have been treated with this method and 22 implants have been placed. The mean follow-up after final prosthetic rehabilitation has been 16 months; survival rate has been 100%. Despite the small number of patients and the short follow-up, preliminary results have shown very promising results.