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Biomedical subjects

G A Zarb

Publications and source records attributed to G A Zarb.

At least 19 recordsLinked to original sources
PubMed1992

Dental implants and decision making.

Treatment choice and effectiveness in prosthodontics has largely depended on educated anecdote and asseveration. Still, this approach has to a very large extent enabled dentists to enrich the quality of their patients' lives. However, the trade-off between the need for prosthetic intervention per se and the biologic price inherent in certain therapeutic endeavors has demanded strict concerns regarding clinical decision making and treatment outcomes. The technique of implant prosthodontics is certainly one that has focussed such concerns, particularly since the concept of osseointegration was introduced to North American dentists at the 1982 Toronto Conference. Clinical research and opinion in this area have elicited both clinical euphoria and polarization vis-a-vis newer possibilities for resolving the predicaments of partial or complete edentulism. The past decade has witnessed clinical trials, as well as highly relevant exemplary reports, on the application of the osseointegration technique. It is now necessary to compare the merits of implant prosthodontics to traditional therapies, and to determine those criteria which comprise optimal functional and aesthetic restoration, with minimal risk of morbidity, along with cost concerns. This paper seeks to provide a systematic and rational basis for the identification of such criteria.

Contraindications↗
PubMed1991

Osseointegration and the edentulous predicament. The 10-year-old Toronto study.

This prospective study at the University of Toronto reports the 5-10-year results of treatment of edentulous patients with osseointegrated implant supported bridges. It comprised 46 consecutively treated patients, chosen because optimisation of traditional prostheses was not successful and because they were in sufficiently good health to allow minor out-patient surgery. Two hundred and seventy-four implants were surgically placed in 49 arches (three patients were treated in both arches) between October 1979 and March 1984. At the end of the 5-10-year observation period, 242 (88.32%) of the implants remained osseointegrated and 233 or 85.04% of these implants were used to support 43 fixed bridges and five overdentures. Nine implants, though osseointegrated, were not exposed and were not used to support the prostheses. Forty-eight of the 49 arches continue to be successfully restored with implant retained prostheses.

Adult↗
PubMed1991

Quantitative immunohistochemical analysis of keratins and desmoplakins in human gingiva and peri-implant mucosa.

Quantitative immunohistochemistry was used to compare the distributions of keratins and desmoplakins in human gingiva and peri-implant mucosa (three specimens each). In gingiva, keratin 1 (a marker of cornification) and desmoplakins I & II (markers of desmosomes) stained most heavily in granular strata followed by corneal strata; keratin 13, a marker of non-cornifying stratified squamous cells, stained most heavily in suprabasal strata of oral sulcular epithelium. Keratin 19, a marker for junctional epithelium, stained the basal stratum of oral sulcular epithelium most heavily. In peri-implant mucosa, the patterns of staining were similar, except that staining for desmoplakins I & II was generally significantly reduced compared with gingiva, and junctional epithelium co-expressed keratins 13 and 19. Peri-implant junctional epithelial cells attached to titanium implant abutments were removed by trypsin/EDTA digestion, and also exhibited co-expression of keratins 13 and 19. Inflammatory cell infiltration was associated with reduction of keratin 1 staining in gingiva. The data indicate that the epithelia of gingiva and peri-implant mucosa are not composed of identical cell populations.

Analysis of Variance↗
PubMed1991

Immunohistochemical localization and quantification of desmoplakins I & II and keratins 1 and 19 in plastic-embedded sections of human gingiva.

We developed immunohistochemical and image analytical techniques to localize and quantify keratins and desmoplakins in sections of plastic-embedded human gingiva. Acetone fixation followed by plastic embedding of gingiva provided excellent morphology and permitted immunohistochemical detection of keratins 1 and 19 and desmoplakins I & II after 2.5-min trypsin digestion. Quantitative image analysis demonstrated that different volume densities of staining of each marker were associated with specific epithelial strata. Keratin 1 stained most heavily in granular strata, followed by corneal and spinous strata; keratin 19 stained most strongly in the basal layer; desmoplakins I & II stained most strongly in the granular and corneal strata. These findings confirm that variations of keratin and desmoplakin expression in these epithelial are associated with regional patterns of epithelial differentiation.

Cell Differentiation↗
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

The longitudinal clinical effectiveness of osseointegrated dental implants: the Toronto Study. Part II: The prosthetic results.

Forty-six patients who had shown chronic maladaptive behavior in using complete dentures were treated with osseointegrated implant-supported prostheses. Forty patients needed mandibular treatment, three patients needed treatment in the maxillae, and three required treatment in both dental arches. At the most recent data collection (4 to 9 years after surgical placement of the implants), the 49 dental arches remained successfully treated with 44 implant-supported fixed partial dentures and five implant-supported overdentures. The efficacy of the osseointegration technique in maladaptive prosthetic patients is demonstrated in this descriptive study.

Adult↗
PubMed1990

The longitudinal clinical effectiveness of osseointegrated dental implants: the Toronto study. Part III: Problems and complications encountered.

Two hundred seventy-four implants were placed in 49 dental of 46 consecutively treated patients. The success rate for individual implants in this study, 4 to 9 years after placement, was 89.05% and for the prosthetic treatment it was 100%. Problems, and complications were observed and recorded at stage I surgery, between stage I and stage II surgery, at stage II surgery, and in the healing period that followed. Also noted were the complications subsequent to prosthodontic treatment and during the years of follow-up. Virtually al of the problems encountered were iatrogenic in nature. These clinical results indicate a safe retrievable technique with negligible associated morbidity.

Dental Implantation, Endosseous↗
PubMed1990

The longitudinal clinical effectiveness of osseointegrated dental implants: the Toronto study. Part I: Surgical results.

In this prospective study, 46 edentulous patients who had undergone traditional denture optimization therapy without success were treated with osseointegrated implants according to the surgical protocol described by Dr. P.I. Branemark. Two hundred seventy-four implants were placed in 49 dental arches--43 mandibles and six maxillae. At the time of writing, 4 to 9 years after insertion of the implants, 244 or 89.05% remained osseointegrated. Of the 262 implants in place more than 5 years, 232 or 88.55% were still integrated. The implant success criteria developed in this clinical study endorsed the predictably favorable outcome of the Branemark technique.

Adult↗
PubMed1990

Terminal dentition in elderly patients and implant therapy alternatives.

The advent, in recent years, of a tried, tested and reliable implant technique such as the Brånemark system, has revolutionized the treatment options open to the prosthodontist. For the edentulous elderly patient the prospects for enhanced quality of life due to the restoration of oral function, comfort and appearance have never been better. For the prosthodontist the new implant systems provide the opportunity to utilize both fixed and removable appliances in combinations and with the use of overdenture designs, with predictable success.

Aged↗
PubMed1990

[Criteria for determining clinical success with osseointegrated dental implants].

In the past decade, the technique of osseointegration has elicited three general responses in the dental profession. The first and major response has been an enormous clinical satisfaction to resolve difficult prosthetic problems, as well to expand the scope and range of routing prosthetic therapy. A second, if minor, response has been an attempt to deny the documented apparent superiority of the osseointegrated method. The third response has been a very active marketing one, which led to the rapid proliferation of a large number of implant systems, all claiming osseointegration and comparable success to the originally introduced Swedish system. The purpose of this paper is to describe and analyze those clinical criteria which can be used by dentist and researcher to determine the long term success or failure of functioning dental implants. Some attempts had been made to identify criteria which reflected sound scientific consideration of long term host acceptance of functioning implants. However, these criteria where a reflection of the state of the art information as perceived by the authors at the time. It is therefore fair to add that the principle of osseointegration did not feature in our colleagues recommendations. Since it is an axiom that host response must be analyzed and understood if a clinical technique is to be successfully prescribed, we regarded our own and other's published data on clinical results with osseointegration as pivotal in the grouping of criteria which would comprise a reliable yardstick, easy to identify and apply, and which reflected assessment experiences in dental practice and research, mainly in the disciplines of periodontics and prosthodontics.(ABSTRACT TRUNCATED AT 400 WORDS)

Dental Implantation, Endosseous↗
PubMed1989

Criteria for success of osseointegrated endosseous implants.

Because of the proliferation of implant systems, a set of criteria for implant success based on scientific investigations is essential. A review of the literature and the analysis of the results indicate that six criteria are supported as valid for determining the clinical success of endosseous dental implants. These criteria are proposed for use in clinical investigation on implants.

Dental Implantation, Endosseous↗
PubMed1989

Microbiota and crevicular fluid collagenase activity in the osseointegrated dental implant sulcus: a comparison of sites in edentulous and partially edentulous patients.

The soft tissues adjacent to osseointegrated dental implants (OII) were investigated using clinical, biochemical and microbiological methods. Tooth and implant crevices were compared in 15 partially edentulous patients, examining 28 peri-implant and 19 periodontal sites, and in 6 edentulous patients, examining 13 implant sites. Sites were classified by standard periodontal indices; the crevicular fluid flow determined; crevicular fluid was collected for collagenase assays; and the subgingival bacterial flora was examined and cultured. Differences in clinical parameters were noted in that implants had significantly less keratinized gingiva and deeper probing depths. Crevicular fluid was present in the OII sulcus but the crevicular fluid flow did not differ from that observed from tooth sites either in the partially edentulous or edentulous patients. Tissue collagenase activity and collagenase inhibitor were detected in the implant crevicular fluid and, as in periodontal sites, a strong inverse relationship was found between the levels of active collagenase and collagenase inhibitor. Microbiology included darkfield microscopy, anaerobic culturing for total colony forming unit counts and identification of black pigmented Bacteroides (BPB). Few differences were observed between implants and teeth in partially edentulous patients, indicating that crevices around teeth may act as reservoirs of bacteria which can colonize implant sites. A higher percentage of BPBs and wet spreaders (Capnocytophaga) was noted at partially edentulous implant sites when compared with edentulous implant sites, perhaps reflecting the lower numbers of periodontal pathogens present in edentulous mouths. Overall, the characteristics of implant sulci appear to be similar to periodontal sulci with respect to crevicular fluid flow and microflora.

Adult↗
PubMed1989

Use of provisional prostheses with osseointegration.

The ingenuity that has characterized the fabrication of provisional prostheses has been readily adapted to the osseointegration technique. Implant abutments do not need protection during final prosthesis fabrication stages as teeth do. However, compelling arguments can be made in favor of esthetic, comfortable, and functional provisional prostheses supported by implants, even if they are worn for only a few weeks. The prosthodontic contribution to a patient's quality of life throughout all stages of treatment is thereby enhanced.

Dental Implantation, Endosseous↗