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Biomedical subjects

T Jemt

Publications and source records attributed to T Jemt.

At least 19 recordsLinked to original sources
PubMed1992

Functional adaptation to full-arch fixed prosthesis supported by osseointegrated implants in the edentulous mandible.

The objective of the present study was to assess possible adaptive functional changes in the masticatory system after insertion of fixed prostheses supported by osseointegrated implants in the edentulous mandible. Registrations of mandibular movement characteristics and maximal biteforce were performed at insertion and after 1 week, 3 months and 1 year after connection. The duration of the opening and closing phase decreased and maximal biteforce increased significantly (p < or = 0.05-0.001) from connection of the prostheses to the annual check-up. However, the process of functional adaptation implied 2 identified stages. An immediate phase that occurred within the 1st week, probably due to altered impact from mechano-sensitive receptors and a later more time-dependent phase, based on learning and new cortical engrams. Accordingly, the process of adaptation will continue over a long period of time.

Adaptation, Physiological↗
PubMed1992

Demographical, odontological, and psychological variables in individuals referred for osseointegrated dental implants.

Edentulism and/or the wearing of a removable denture always requires adaptation, not only on a functional, but also on an emotional, level. Four hundred and seventy-three patients referred for treatment with osseointegrated implants due to problems with removable prostheses entered the study and 315 (66.6%) completed it. The average age was close to 60 yr, and the majority of patients were women. The average time of edentulousness was 14.3 yr. Twelve percent experienced profound negative effects from wearing dentures, this to an extent that it led to overt psychological and social effects. Subjective ratings revealed that functional and/or intra-personal effects were of higher significance than social consequences. The group was found to be more depressed than average as well as having an external health locus of control orientation.

Adaptation, Psychological↗
PubMed1992

Loads and designs of screw joints for single crowns supported by osseointegrated implants.

The problem of screw stability was approached in this study by calculating the maximum occlusal forces in vivo for patients with single implant restorations (which use only one screw to secure the prosthetic reconstruction to the implant). The measurements of occlusal forces together with geometric parameters for the individual patients were used to determine the necessary holding capabilities of the screw joint. Different screw designs were tried in bench test situations and the results were compared with clinical situations. A gold alloy screw with a flat head and high tightening torque (35 Ncm) produced the best results.

Bite Force↗
PubMed1992

A multicenter study of overdentures supported by Brånemark implants.

Nine clinical centers participated in a prospective study of overdentures supported by Brånemark implants in the maxilla or mandible. The study initially comprised 133 patients provided with 117 implants placed in the maxilla and 393 implants placed in the mandible. The preliminary results indicate a success rate in the mandible comparable with the reports on fixed prostheses. Conversely, overdenture treatment in the maxilla seems to be less favorable than previous reports of fixed restorations. The differences between the fixed and the present overdentures in the maxilla were mainly based on differences in patient selection and bone quality. A total of 32 implants was mobile and removed and another 29 implants were lost to follow-up because of patient dropout up to the first annual checkup after denture placement. A higher implant failure rate occurred in the maxilla. Mucosal reactions were also more unfavorable around implants placed in the maxilla.

Adult↗
PubMed1992

Fixed implant-supported prostheses with welded titanium frameworks.

Eighty-six edentulous patients provided with Brånemark implants were randomly selected for fixed prostheses with modified framework designs. This study describes alternative laboratory techniques in which premachined titanium components are welded together to form the framework. Clinical experience, following the patients for 1 year after placement, indicates that it is a predictable technique with a similar pattern of complications as experienced by patients with cast frameworks supported by implants. The prostheses are considered to be slightly more bulky than cast frameworks, but seem to have, on a clinical level, a better fit to the implants.

Adult↗
PubMed1992

Failures and complications in 127 consecutively placed fixed partial prostheses supported by Brånemark implants: from prosthetic treatment to first annual checkup.

Ninety-six partially edentulous maxillae and mandibles were consecutively treated with 127 freestanding fixed prostheses supported by 354 implants. The patients were followed for 1 year and the overall success rate was 98.6% for the examined implants. None of the inserted prostheses was lost during the observation period. The most commonly reported problems during the first year of function were related to loose gold screws and esthetic complaints, complications that were easily resolved. Furthermore, the total number of complications was low and was less than has been reported for routine full-arch fixed prostheses.

Adolescent↗
PubMed1992

Failures and complications in 92 consecutively inserted overdentures supported by Brånemark implants in severely resorbed edentulous maxillae: a study from prosthetic treatment to first annual check-up.

Overdentures were consecutively inserted in 92 severely resorbed maxillae and followed for 1 year. The dentures were supported by a total of 430 implants. Of these, 69 (16%) became loose and were removed during the follow-up period. The mobile implants caused 7 complete failures of the overdenture treatment. Postinsertion maintenance was more extensive for the overdentures than for fixed prostheses supported by implants. Problems arose in relation to the mucosa around the implants, and there were also fatigue fractures of the acrylic resin and the retentive clips. Fewer speech problems were reported in the overdenture group when compared to those with fixed prostheses.

Adult↗
PubMed1991

Early failures in 4,641 consecutively placed Brånemark dental implants: a study from stage 1 surgery to the connection of completed prostheses.

This study comprised 4,641 Brånemark dental implants, which were retrospectively followed from stage 1 surgery to completion of the prosthetic restorations. The implants were placed during a 3-year period (1986 to 1988) in 943 jaws, representing 889 patients with complete and partial edentulism. The jaw and sex distribution revealed a predominance of mandibles (564/943) and females (534/943). The mean age of the patients was 57.5 years (range 13 to 88 years) at implant placement. Only 69 (1.5%) fixtures failed to integrate, and most losses were seen in completely edentulous maxillae (46/69), in which the jaw bone exhibited soft quality and severe resorption. A preponderance of failures could also be seen among the shortest fixtures (7 mm). A majority of the mobile implants were recorded at the abutment connection (stage 2) operation (48/69).

Adolescent↗
PubMed1991

Adaptive changes of masticatory movement characteristics after rehabilitation with osseointegrated fixed prostheses in the edentulous jaw: a 10-year follow-up study.

The aim of this study was to assess possible adaptive changes in the masticatory rhythmical pattern after insertion of an osseointegrated fixed denture. Registrations of masticatory cycle duration, mandibular velocity, and displacement were performed before and 2 months and 10 years after rehabilitation. No major changes except for a decreased occlusal level phase had occurred regarding cycle duration over the years. However, a significantly higher mandibular velocity and greater displacement were recorded 2 months after rehabilitation. This trend was further established in the long term. Temporal timing of rhythmical chewing seems to be relatively consistent, suggesting that the central pattern generator driving output over time is constant.

Adaptation, Physiological↗
PubMed1991

Failures and complications in 391 consecutively inserted fixed prostheses supported by Brånemark implants in edentulous jaws: a study of treatment from the time of prosthesis placement to the first annual checkup.

A total of 391 edentulous maxillae and mandibles was consecutively treated with routine fixed prostheses, supported by 2,199 implants. The patients were followed for 1 year; the overall success rate was 99.5% and 98.1% for the prostheses and implants, respectively. The number of severe complications was low, but it was possible to identify a significantly higher ratio of problems in the maxillae throughout the observation period than for the mandibles. While many problems occurred in both the maxillae and mandibles, there were also problems more typical for each jaw. Diction and fractures of resin teeth were more common problems in maxillae; cheek and lip biting was a more frequent postinsertion complication in the treatment of mandibles. Most problems were easily resolved, and the retrievability of the prostheses was of great advantage.

Adult↗
PubMed1991

In vivo load measurements on osseointegrated implants supporting fixed or removable prostheses: a comparative pilot study.

Load was measured in vivo on a single terminal abutment cylinder by means of a strain gauge technique. The clinical measurements were made on one female patient (age 62) provided with six implants in the edentulous maxilla. A fixed prosthesis was tested initially, followed by an overdenture supported by a bar connected to the implants. The results indicated that a significant force could be introduced when connecting the framework. Furthermore, measurements showed that compression/tension forces were lower in the overdenture situation. However, the preliminary data also indicated relatively higher bending moments on the implant when the overdenture was loaded.

Bite Force↗
PubMed1991

Osseointegrated implants for single tooth replacement: a 1-year report from a multicenter prospective study.

One hundred seven dental implants were inserted to support single tooth restorations in 92 patients participating in a prospective multicenter investigation. Only three implants (2.8%) were lost after 1 year of clinical function. Most of the remaining restorations were esthetically successful by using modified components. The gingival condition was healthy around the single crowns and coincided well with the clinical situation around the permanent teeth. The most obvious problem experienced during the first year was related to loose abutment screws. Twenty-six percent of the screws retaining crowns were retightened during the observation period, but the frequency of loose screws had a tendency to decrease as the study progressed.

Adult↗
PubMed1990

Long-term follow-up study of osseointegrated implants in the treatment of totally edentulous jaws.

This study reviews the long-term outcome of prostheses and fixtures (implants) in 759 totally edentulous jaws of 700 patients. A total of 4,636 standard fixtures were placed and followed according to the osseointegration method for a maximum of 24 years by the original team at the University of Göteborg. Standardized annual clinical and radiographic examinations were conducted as far as possible. A lifetable approach was applied for statistical analysis. Sufficient numbers of fixtures and prostheses for a detailed statistical analysis were present for observation times up to 15 years. More than 95% of maxillae had continuous prosthesis stability at 5 and 10 years, and at least 92% at 15 years. The figure for mandibles was 99% at all time intervals. Calculated from the time of fixture placement, the estimated survival rates for individual fixtures in the maxilla were 84%, 89%, and 92% at 5 years; 81% and 82% at 10 years; and 78% at 15 years. In the mandible they were 91%, 98%, and 99% at 5 years; 89% and 98% at 10 years; and 86% at 15 years. (The different percentages at 5 and 10 years refer to results for different routine groups of fixtures with 5 to 10, 10 to 15, and 1 to 5 years of observation time, respectively.) The results of this study concur with multicenter and earlier results for the osseointegration method.

Adult↗
PubMed1990

Oral function in patients treated with prostheses on Branemark osseointegrated implants in partially edentulous jaws: a pilot study.

To study the oral function of partially edentulous patients treated with fixed prostheses on osseointegrated implants, recordings of the masticatory efficiency and occlusal perception of thickness were performed. The retrievable fixed partial prostheses were used to study the immediate impact of reduced fixed occlusal support on masticatory efficiency. The masticatory efficiency was subjectively satisfactory but objectively lower when compared to naturally complete dentate persons. Furthermore, the immediate impact of reduced fixed occlusal support was compromised masticatory efficiency, which was more pronounced when the occlusal support was removed on either side.

Aged↗
PubMed1990

Clinical evaluation of angulated abutments for the Brånemark system: a pilot study.

Where fixture placement and inclination had not been optimal from a restorative perspective, angulated abutments were used to overcome compromised esthetic and functional results in situations of complicated anatomy. The angulated abutment is a treatment adjunct that provides flexibility for ensuring successful treatment when a variety of reconstruction problems are confronted.

Dental Abutments↗