SEARCH · PubMed Health

Results for “Prosthesis Retention”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources

PubMed1995

Influence of the suprastructure on the peri-implant tissues in beagle dogs.

The purpose of this study was to compare clinical, radiographic and histological differences around titanium oral implants loaded with either acrylic-veneered metal or ceramo-metal fixed prostheses. Five beagle dogs were used in this investigation. At the beginning of the study, all mandibular premolars and first molars were extracted. After 3 months of healing, 2 Brånemark implants were installed on each side of the mandibles. Three months later, abutments were inserted on each implant and a daily oral hygiene regime was initiated. One month after abutment connection, the implants on one side of the mandible were restored with an acrylic-veneered metal fixed prosthesis, whereas, on the other side a ceramo-metal fixed prosthesis was inserted. The prostheses were constructed in occlusion with the maxillary first molars. The following clinical parameters were measured around each implant at this time (i.e., baseline), and thereafter, at monthly intervals up to 5 months: Plaque Index; Gingival Index; implant mobility (using the Periotest); probing depth and clinical attachment level (using the Florida Probe). In addition, standardized radiographs were taken at baseline and 5 months after insertion of the prostheses and evaluated by subtraction radiography. Another Brånemark fixture was installed on each side of the mandibles 3 months before the end of the study. These implants remained unloaded and submerged for the entire study period. Five months after prosthesis insertion, the animals were killed, and implants with their supporting peri-implant tissues were processed for histological evaluation. Analyses of the clinical, radiographic and histometric parameters revealed no significant differences between the acrylic-veneered and ceramometal loaded implants.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrylic Resins↗

PubMed1995

Ten-year survival rates of fixed prostheses on four or six implants ad modum Brånemark in full edentulism.

A series of 156 consecutive fully edentulous patients were rehabilitated by means of fixed prostheses on either 4 or 6 screw-shaped titanium implants. This retrospective study calculated survival rates for both prostheses and individual implants. Only patients with a 10-year follow-up were considered. The implant lengths were 10 (90%) or 7 mm. They were all inserted after pretapping. In the mandible 13 and 59 prostheses were installed on respectively 4 and 6 implants. In the upper jaw the respective numbers were 14 and 70. Both groups (4 versus 6 implants) were age- and gender-matched. A reduced jaw bone volume was the major reason for limiting the number of implants to 4. Although a tendency existed for an increased failure rate in patients with only 4 implants, the survival rate for both individual implants and prostheses was the same in both groups at the end of the 10-year observation period. The present tendency of some clinicians to install as many implants as possible in full edentulism should be seriously questioned.

Adult↗

PubMed1996

On the influence of superstructure connection on implant preload: a methodological and clinical study.

In a combined in vitro and in vivo study strain gauges were used to register the deformation in two terminal implant abutment cylinders, when connecting three different prosthetic appliances. The prosthetic constructions were placed on the abutments and fastened in vitro and in vivo by using different torque sequences. Furthermore, in the in vitro situation the three medial abutments were replaced by abutments which were 100 microns shorter. The results show that even if the prosthetic constructions were judged to have a good clinical fit, relatively large External Preloads were registered both in vitro and in vivo. No significant differences in axial force or in bending movement were found between the torque sequences in vivo. There were, however, significant differences in axial force as well as in bending moment in the in vitro experiment. When the shorter medial abutments were used in vitro, a change in the axial force of approximately 200 N was registered. The results confirm that the methodological approach used in this study is valid when evaluating preloads.

Analysis of Variance↗

PubMed1996

Bacterial colonization on internal surfaces of Brånemark system implant components.

The aim of the present study was to examine the microbiota on the internal surface of the components of 28 Brånemark implants in 10 partially edentulous patients who had been treated with 1 fixed partial prostheses each. The prostheses had been in function for 1 to 8 years. The fixed prostheses were checked for mobility and removed. The abutment screws were loosened and classified as stable, easily removed or loose. Then, bacterial samples were obtained from the various internal surfaces of the implant system. Estimation and identification of the most predominant species was performed on the blood agar plates. Identification was based on Gram reaction, oxygen sensitivity and biochemical tests. Internal surfaces of different components of the Brånemark implants, after varying periods of function in the oral cavity, consistently harboured a heterogeneous and primarily anaerobic microbiota. The individual samples showed a great variation. No relation could be seen between type and length of abutment, abutment stability, bone loss and type and number of microorganisms found in the samples. The flora consisted mainly of facultative and anaerobic streptococci, Gram-positive anaerobic rods such as Propionibacterium, Eubacterium and Actinomyces species and Gram-negative anaerobic rods including Fusobacterium, Prevotella and Porphyromonas species. There are reasons to suggest that this presence of bacteria is the result of (i) a contamination of the fixture and abutment components during the 1st and/or 2nd stage of implant installation and/or (ii) a transmission of microorganisms from the oral environment during function subsequent to bridge installation.

Aged↗

PubMed1996

Loss of osseointegration caused by occlusal load of oral implants. A clinical and radiographic study in monkeys.

The breakdown of bone around oral implants following excessive occlusal load or plaque accumulation was evaluated in monkeys. 5 screw type implants of pure titanium (Astra) were inserted in the mandible of 4 monkeys (Macaca Fascicularis). 2 implants were placed in each of the lateral segments and 1 in the frontal area. Each monkey was provided with 2 cemented splints covering the premolars and molars in the right and left side of the maxilla, respectively. 6 months after insertion of the fixtures, a fixed partial prosthesis was mounted on the 2 implants in one of the lateral segments. The prosthesis was in supra-occlusal contact with the antagonizing splint. Each prosthesis was replaced during the course of the experiment. The renewed prosthesis caused a lateral displacement of the mandible during occlusion, and therefore resulted in a lateral rather than axial excessive occlusal load. Implants retaining the prosthesis were brushed 1 x a week and subgingival cleaning was performed 1 x a month. The remaining implants were never cleaned and, additionally, a cotton cord was placed passively around each of these to promote plaque accumulation. 5 out of 8 implants with excessive occlusal load lost osseointegration (mobility and peri-implant radiolucency). The loss of osseointegration was observed 4.5 months to 15.5 months after the occlusal overload was commenced. None of the implants with plaque accumulation lost osseointegration, although an average loss of 1.8 mm in the radiographic bone level was assessed after 18 months.

Alveolar Bone Loss↗

PubMed1996

Correlations between radiographic, clinical and mobility parameters after loading of oral implants with fixed partial dentures. A 2-year longitudinal study.

The aim of present study was to correlate the changes in the peri-implant tissues occurring after functional loading of non-submerged titanium implants and assessed by radiographic, clinical and mobility measurements. 11 patients with distal extension situations received 18 implants of the ITI Dental Implant System. After a healing period of 3 months, the suprastructures were fabricated and seated 5 months post-surgically. For the assessment of peri-implant bone changes, standardized vertical bitewing radiographs with reproducible exposure geometry were evaluated using computer assisted densitometric image analyses (CADIA) and bone height measurements. Since the radiographic evaluations were performed at mesial and distal sites only, the clinical parameters from these implant aspects were included in the analysis. Clinical periodontal parameters modified for the use around implants were obtained, damping characteristics were expressed as Periotest readings and standardized radiographs were obtained at 1, 3, 6, 12 and 24 months after loading. In addition, radiographs were also taken at the start of functional loading. The data obtained from this small sample of implants demonstrated a wide range of different tissue alterations when using radiographic, clinical and mobility assessments. The parameters of probing attachment level (PAL) in combination with radiographic parameters obtained at 1, 3, and 6 months after loading were good predictors for the peri-implant tissue status at 2 years. This was shown by means of multiple stepwise regression analyses. Mobility measurements did not reveal valuable predictive information with the statistical models applied. Assessments of probing attachment levels using periodontal probes rendered information on peri-implant tissue alterations, which were closely correlated to the radiographically measurable peri-implant bone changes.

Adolescent↗

PubMed1996

Transversal fixation of restorations in combination with the Octa abutment of the ITI Dental Implant System.

In aesthetically demanding locations of the dentition, the replacement of a single tooth by means of an oral implant is often difficult because of technical limitations of the abutments systems used. The transversal Fixation System in combination with the Octa abutment of the ITI Dental Implant System presents a novel development to overcome these limitations. The report describes the engineering and design of this technical development.

Dental Abutments↗

PubMed1996

Simultaneous force measurements in 3 dimensions on oral endosseous implants in vitro and in vivo. A methodological study.

A novel piezo-electric force transducer was developed that is mounted directly on ITI-implants and allows for simultaneous force measurements in 3 dimensions. The reliability of this measuring method in vitro and in vivo was evaluated. For test and calibration measurements 5 edentulous patients with 2 mandibular implants were selected and master casts obtained with original implants in situ. Preload of the abutment screw was measured with a torque controller by repeated tightening and loosening. The introduction of additional preloads when bar connectors or telescopes were mounted was examined on the casts and in the mouth. Tests were carried out to identify the influence of screw tensions on force measurements by loading the implants in vertical and transverse directions. Calibration measurements in vivo and in vitro were carried out by means of a spring balance. A regression model was calculated to analyze the influence of the applied preload on measured forces. The mean preload value was 315, ranging from 200 to 480N. A significant correlation of applied loads to measured forces was found (r = 0.99). It was independent of the preload in vertical direction but dependent in transverse direction. No additional tension of the abutment screw was ever observed when bars were mounted. Calibration measurements with the spring balance showed that bars contribute to load sharing between the implants. Comparable results were found for all measurements in vitro and in vivo. It was concluded that the new piezo-electric transducer is an adequate instrument to measure forces in 3 dimensions on ITI-implants.

Dental Abutments↗

PubMed1997

Periodontal parameters of osseointegrated dental implants. A 4-year controlled follow-up study.

The aim of this study was to evaluate the periodontal parameters of osseointegrated dental implants. The condition of the peri-implant mucosa was assessed using periodontal parameters, i.e., of plaque index, bleeding on probing, probing pocket depth, probing attachment level and Periotest scores as well as a radiographic parameter, over a 4-year follow-up period. 32 non-submerged ITI dental implants, all placed in the mandible, were studied in 12 patients who had good oral hygiene. All patients were regularly recalled at 6-month intervals. The overall implant success rate was 100%. None of the implants showed any signs of inflammation, radiographic bone loss or any detectable mobility during the follow-up period. Methods similar to those used to evaluate the natural dentition were effectively employed to assess the clinical status of the dental implants. The diagnostic value of these parameters could not, however, be determined from this study due to the absence of any peri-implant tissue complications. The results indicated that some periodontal parameters of healthy peri-implant mucosa might be slightly different from healthy periodontal tissue.

Alveolar Process↗

PubMed1998

A 5-year randomized clinical trial on the influence of splinted and unsplinted oral implants in the mandibular overdenture therapy. Part I: Peri-implant outcome.

Thirty-six completely edentulous patients were enrolled for a 5-year prospective study testing the treatment outcome between splinted and unsplinted implants retaining a mandibular hinging overdenture. The patients were randomized into 3 groups of equal size depending on the attachment system used such as: magnets, ball attachments or bars (reference group). Only 1 implant out of the 72 had failed at the abutment stage. Not a single implant failed during the 5-year loading period. The accumulation of plaque was significantly higher for the Magnet than for the Ball group. Bleeding on probing, as well as marginal bone level, attachment level and Periotest values did not statistically differ among the groups, neither at year 1 nor at year 5. However, the Periotest values were significantly lower at year 5 compared to year 1 for all groups, which indicates a higher rigidity at the bone-implant interface. No correlation was found between bleeding on probing and marginal bone loss. We conclude that the connection state of 2 implants retaining a hinging overdenture did not influence the peri-implant outcome.

Adult↗

PubMed1998

Five-year prospective follow-up report of the Astra Tech Dental Implant System in the treatment of edentulous mandibles.

This report of the 1st 2 prospective studies using the Astra Tech Implant System and fixed detachable bridges for rehabilitation of mandibular edentulism, presents clinical and radiographic data at the 5-year follow-up. The original material comprised 109 subjects, 56 of whom had been included in the original study, using the 1st generation Astra Tech Implant. Two subjects were excluded and the 3-year follow-up report was based on the remaining 54 subjects and 310 fixtures. After some minor changes to the fixture and the abutment, the 2nd generation Astra Tech Implant was used in 53 subjects and 308 fixtures. In all 16 subjects were lost to follow-up and the 5-year results are based on the remaining 91 subjects with 517 fixtures in function: 5 fixtures were lost due to mobility at abutment installation and during the 1st year, 2 fixtures were removed due to pain, and after 4 years in situ 1 fixture failed. As no clinical or radiographic differences were obvious in the annual registrations of the 2 studies the results have been combined. The fixed bridges were removed at 3 and 5 years to test each fixture and none was mobile. The cumulative fixture survival rate at 5 years was 98.7% and the bridge survival rate was 100%. Of the sites 82% were plaque free, and 96.8% showed no signs of inflammation. Over the 5-year period after bridge insertion, i.e. from baseline registration, there was only minor deterioration in marginal bone levels as measured on standardized intraoral radiographs: the mean differences in mm and standard deviations (SD) were -0.09 (0.27) in the 1st year, -0.20 (0.40) in the 3rd year, and -0.26 (0.53) in the 5th year. According to the stringent clinical and radiographic criteria by Albrektsson and co-workers, the successful treatment outcome and the survival rate in 91 subject over 5 years, indicates that the Astra Tech Dental Implant System with fixed detachable bridges is an appropriate method for rehabilitation of mandibular edentulism.

Adult↗

PubMed1999

Clinical and radiological results of patients treated with three treatment modalities for overdentures on implants of the ITI Dental Implant System. A randomized controlled clinical trial.

In a randomized controlled clinical trial carried out at the Ignatius teaching hospital in Breda, The Netherlands, 110 edentulous patients with severe mandibular bone loss were treated with implants of the ITI Dental Implant System using 3 different treatment strategies: a mandibular overdenture supported by either 2 implants with ball attachments, 2 implants with an interconnecting bar, or by 4 interconnected implants. In this study, results of clinical and radiographic parameters were evaluated and compared over a period of 19 months after implant placement. A total of 283 ITI Dental Implants were placed. Six implants (2%) were lost during the osseointegration period. No further implant losses occurred after that. At the 19 month evaluation mean values and standard deviations for bleeding index were 0.51 +/- 0.5 (bleeding incidence = 70%) and for plaque index they were 0.46 +/- 0.5 (plaque incidence = 45%). The mean values and standard deviations for probing depth and loss of attachment were 2.7 +/- 1.1 mm and 0.26 +/- 0.6 mm respectively. The radiographic evaluation showed a mean bone loss of 1.5 mm +/- 0.26 after 19 months for all the implants. In cases with 4 interconnected implants there was significantly more bone loss around the central 2 implants (2.1 +/- 0.31 mm) in comparison with the lateral 2 (1.4 +/- 0.25 mm). No significant correlations were found between plaque and bleeding indices and bone loss.

Alveolar Bone Loss↗

PubMed2000

An in vitro study on compensation of mismatch of screw versus cement-retained implant supported fixed prostheses.

In common practice a perfect fit of the prosthetic framework with the implant abutments is almost impossible to achieve. The mismatch, which is principally induced by the technological process adopted to manufacture the fixed prostheses, strains the framework thus generating constraint reactions. These are static forces that load the implant components and the bone at the implant-bone interface and may cause the bone remodelling. Depending on the magnitude of such forces, i.e. depending on the magnitude of the mismatch, the bone remodelling may lead to the loosening of the screws and of the implant-bone interface and hence cause implant failure. The present study shows an in vitro comparison of 3 different connecting abutments (standard, EsthetiCone and CerAdapt, Nobel Biocare AB, Göteborg, Sweden) with relation to the mechanical stresses induced by geometrical mismatches (technology induced errors). Two experimental devices were purposely realized and used to assess the ability of the different abutments to compensate errors. One was designed for translation errors and the other for rotation errors. The experimental apparatus set-up includes 2 freestanding implants supporting a prosthetic structure and the connecting abutments. The implants and the abutments were used as delivered by the manufacturer, while the prostheses were purposely realized and instrumented with strain gauges. The data obtained with the error devices do not give quantitative information on what happens in clinical applications where the implants are connected to living bone, which is a tissue much more deformable than the steel used for the error devices. Results allow direct comparisons of the behaviour of the different investigated abutments with respect to position errors. The CerAdapt system (cement retained ceramic abutments) showed the least strain in presence of translation errors. The standard system (screw retained abutments) showed the least strain in presence of rotation errors.

Biomechanical Phenomena↗

PubMed2000

Prosthodontic considerations.

The prosthodontic section of the 1997 ITI Consensus Conference in Vitznau, Switzerland, examined a broad spectrum of issues related to the prosthodontic phase of dental implant therapy. Topics included diagnosis and treatment planning, considerations for the use of ITI prosthodontic components, management of the partially edentulous patient, management of the edentulous patient, implant occlusion, and the use of narrow- and wide-body implants. The management of partially and totally edentulous patients will be discussed in separate papers. This paper is written so that each major consensus point discussed by the prosthodontic section is the first sentence of a paragraph. The remainder of each paragraph serves as background information or justification for the consensus statement. It should be noted that agreement on all points was reached by voting within the prosthodontic section. Many of the consensus statements were reached unanimously, while some were reached through compromise and split vote. Not all of the points presented here were presented to the plenum session on the final day of the conference.

Cementation↗

PubMed2000

Management of the edentulous patient.

Being edentulous is a handicap, and the main objective of implant placement is to provide support of fixed prostheses or to stabilize complete dentures in the edentulous jaw. Clinical experience and clinical studies have demonstrated the broad application of non-submerged ITI implants in prosthetic therapy in standard sites and in situations of advanced atrophy or substantial loss of tissue. The ITI implant was developed for universal use in partially and completely edentulous patients and for replacement of single missing teeth. The abutment system offers the choice of both removable and fixed prostheses with identical secondary parts. The present article describes the use of ITI implants for prosthodontic rehabilitation in the completely edentulous jaw. Indications and various types of fixed or removable prostheses, alternatives and variations of design are discussed. Prosthetic design is dependent on the number and location of implants, and conversely, the number of implants that can be placed will determine the choice of prosthesis. Treatment planning in general and with respect to individual anatomic-morphologic conditions is described for the upper and lower jaw. Details of clinical procedures with ITI implants related to the specific design of prostheses are presented. Biomechanical aspects of fixation and stabilization of prostheses and aspects of occlusion to be built up complete the overview.

Cementation↗

PubMed2000

Prosthetic management of the partially dentate patient with fixed implant restorations.

The aim of this chapter is to discuss the current prosthetic management of the partially dentate patient by means of fixed implant restorations in the scope of the ITI(R) Dental Implant System. For that purpose, the related statements defined by the participants of the prosthodontic section of the 1997 ITI Consensus Conference in Vitznau, Switzerland, will be presented, completed by explanatory comments where appropriate. Distinct conceptual differences will be made between the esthetic zone (areas of the dental arches where esthetic considerations are of primary concern) and the non-esthetic zone (regions of the jaws where esthetic aspects do not represent a priority), and between single tooth replacement and multiple unit implant restorations. Furthermore, it is underlined that current clinical concepts should be based on both predictable treatment outcome and cost-effectiveness. In this context, a straightforward surgical and prosthetic protocol is generally preferred in posterior locations of the oral cavity, using a nonsubmerged implant placement comprising an easily accessible implant shoulder location, and subsequently cemented implant restorations, basically according to a traditional prosthodontic approach. In esthetically demanding indications, where normally a distinctly submucosal implant shoulder location is advocated, screw-retained restorations are preferred, based on prefabricated prosthetic components (e.g. machined cast-on copings) to assure optimum surface properties and contour, and to achieve adequate marginal adaptation.

Bicuspid↗

PubMed2001

A comparison of hydroxylapatite coated implant retained fixed and removable mandibular prostheses over 4 to 6 years.

In a 6-year prospective clinical study, 181 hydroxylapatite coated endosseous dental implants were placed into the anterior mandible of 48 patients. Twenty-one patients were treated with fixed prostheses and 27 patients with an overdenture. When the implants were exposed all 181 had integrated. To date, there is 100% survival of all implants and they all retain a functioning prostheses. The initial results were very promising, in both groups the interval success was over 95% in the first 4 years of the study. However, by year 6, the interval success rates had fallen to 83% for both the fixed and removable groups. This study also compares the construction and maintenance complications for the two types of restorations. The clinical time taken, after implant exposure, to construct the prostheses was similar whether the fixed (mean of 8 visits) or removable option (mean of 7 visits) was chosen. However, the removable restoration cost less than half the price of the fixed when both technical time and implant component costs were evaluated. Maintenance for both groups was higher than expected, but patients required more appointments in the removable group both in the first year and beyond. Regarding the prostheses itself, the incidence of remakes, relines and general adjustments was higher in the removable group. This study has shown that the overdenture offers an effective and initially a more economical alternative to the fixed prostheses, in the treatment of the edentulous mandible. However, long-term maintenance of such a prosthesis can be significant.

Adult↗

PubMed2001

A retrospective analysis of factors associated with multiple implant failures in maxillae.

This retrospective study was designed to verify the factors that influence implant failures. Six prosthodontic clinics in Sweden participated in the study, and together they included a total of 54 patients treated between January 1988 and December 1996. All patients were completely edentulous in the maxilla, and received either a fixed prosthesis or an overdenture supported by at least 4 implants (Brånemark System). Half of the patients belonged to the study group, and an inclusion criterion for this group was that they had lost at least half of their implants. To reduce bias, the patients in the control group were matched to the study group, i.e. they were selected so that both groups were as identical as possible. The results of the study indicate that the control group had a better initial bone support than the study group. Furthermore, the patients in the study group suffered from circumstances that could induce implant failure, such as bruxism, personal grief, depression, as well as addictions to cigarettes, alcohol and/or narcotics. On the study form the clinicians were asked to give their own opinion of the reason for implant failure. The answers given could easily be grouped into 5 different topics, and this experience can be useful to improve patient selection. This study suggests that there are certain factors of importance to consider to prevent a cluster phenomenon of implant failures i.e. lack of bone support, heavy smoking habits and bruxism.

Adult↗