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Biomedical subjects

R M Meffert

Publications and source records attributed to R M Meffert.

At least 19 recordsLinked to original sources
PubMed1992

How to treat ailing and failing implants.

This article describes treatment of the ailing implant (bone loss with pocketing but static at the maintenance checks) and the failing implant (bone loss with pocketing, bleeding upon probing, purulence, and evidence of continuing bone loss irrespective of therapy). Because the surface of the implant is contaminated with endotoxin, it must be detoxified before any regenerative therapy. Studies have shown that citric acid is effective in detoxifying the hydroxyapatite-coated surfaces while tetracycline is more effective in sterilizing the metallic substrate fixtures. Guided tissue regeneration is useful as a "barrier" to prevent exfoliation of the grafted material. Both nonresorbable and resorbable materials have been used with great success. Allografts (freeze-dried bone) and alloplasts (synthetic materials) may be used to achieve a sulcus of decreased depth and possibly some type of osseous regeneration. The author recommends the use of the allograft if the surface is completely detoxified and the alloplast if it is not certain that the surface is sterilized and free of endotoxin. The allograft, being resorbable, will not effect biologic healing against a contaminated surface; hence, the use of the alloplast to "fill" the defect and prevent epithelial invagination.

Alveolar Bone Loss↗
PubMed1992

Fibroblastic growth and attachment on hydroxyapatite-coated titanium surfaces following the use of various detoxification modalities. Part I: Noncontaminated hydroxyapatite.

Hydroxyapatite-coated titanium alloy test strips were treated with chlorhexidine gluconate, stannous fluoride, citric acid, tetracycline HCl, polymyxin B, hydrogen peroxide, and a plastic Cavitron tip: untreated sterile strips served as controls. The strips were incubated with cultured human gingival and periodontal ligament fibroblasts. Image analysis of three photomicrographs of each test strip (original magnification x350) indicated that the tetracycline HCl treatment resulted in significantly greater cellular surface area coverage compared with the other treatments. Citric acid and the plastic Cavitron tip also stimulated cell attachment, although the results from the Cavitron tip were not significantly different from citric acid or the other treatment groups. The remainder of the modalities and the untreated cellular controls experienced similar cellular coverage.

Cell Adhesion↗
PubMed1992

Fibroblastic growth and attachment on hydroxyapatite-coated titanium surfaces following the use of various detoxification modalities. Part II: Contaminated hydroxyapatite.

This study evaluated the ability of various chemotherapeutic and mechanical modalities to detoxify endotoxin-contaminated hydroxyapatite-coated dental implant surfaces as determined by the early attachment and growth of human gingival fibroblasts. Hydroxyapatite-coated test strips were contaminated with purified outer membranes of Escherichia coli and treated with citric acid, hydrogen peroxide, stannous fluoride, chlorhexidine gluconate, tetracycline HCl, polymyxin B, a plastic sonic scaler tip, or left untreated (contaminated and sterile controls). Human gingival fibroblasts were then seeded onto the test strips and incubated for 48 hours. The citric acid-treated strips showed greater cell growth than the other treatments. The plastic sonic scaler tip and the polymyxin B-treated samples exhibited greater cell coverage than the sterile control specimens. The use of citric acid and/or a modified plastic sonic scaler tip may be a valuable adjunct when surgical repair of an ailing hydroxyapatite-coated dental implant is contemplated.

Cell Adhesion↗
PubMed1992

Detoxification of endotoxin-contaminated titanium and hydroxyapatite-coated surfaces utilizing various chemotherapeutic and mechanical modalities.

The surgical repair of the ailing implant may be complicated by the surface effects of pathogenic bacteria and their products. This study evaluated the ability of various chemotherapeutic modalities to detoxify endotoxin-contaminated titanium alloy and hydroxyapatite-coated test strips. Grit-blasted titanium alloy and hydroxyapatite-coated test strips were contaminated with purified outer membranes of Escherichia coli labeled with radioactive 14C. The titanium alloy strips were treated with citric acid, stannous fluoride, tetracycline HCl, chlorhexidine gluconate, hydrogen peroxide, chloramine T, sterile water, a plastic sonic scaler tip, and an air-powder abrasive unit. Hydroxyapatite-coated strips were treated with chloramine T, citric acid, or burnished with sterile water on cotton pellets. Residual lipopolysaccharide levels were measured by liquid scintillation spectrometry. The air-powder abrasive unit removed significantly greater amounts of lipopolysaccharide than all other treatment modalities on titanium samples (P < 0.05). A 60-second burnish with sterile water was able to remove significant amounts of lipopolysaccharide when compared with untreated controls (P < 0.05). Citric acid was superior in the removal of lipopolysaccharide from hydroxyapatite-coated surfaces when compared with the controls or chloramine T (P < 0.01). Detoxification of an implant infected surface may be beneficial when surgical repair of the ailing implant is indicated.

Air Pressure↗
PubMed1992

Dental implants: a review.

The present article is a review presenting an update on the field of dental implants since the World Workshop in Clinical Periodontics in July 1989. Areas that are discussed include following: 1. Biomaterials and the implant interface, and the interaction of these with the environment. 2. Periodontal considerations including data supporting a perimucosal seal of implant to soft tissue and discussion of the endosseous interface between the bone and the implant. 3. Newer techniques of diagnostic imaging and their determination of bone types are related to the future practice of dental implants. 4. Implant selection and the surgical techniques involved in implant placement. 5. Current ideas of implant prosthodontics, implant maintenance, and the treatment of implant failures. 6. Finally, the use of dental implants in the United States and Sweden.

Dental Implantation, Endosseous↗
PubMed1992

Treatment of failing dental implants.

Recent studies show that the bacterial flora in adult periodontitis and peri-implantitis are identical, but there could be a more pathogenic flora (gram-negative bacteria, spirochetes) in the partially edentulous implant case than in the fully edentulous implant case. These data indicate a possible seeding mechanism from the natural tooth pocket to the implant crevice and may place the implant in the partially edentulous case more at risk. Also, understanding of the importance of loading in a progressive sense to prevent retrograde peri-implantitis involving the dental implant has increased; the density of bone must be evaluated more fully to determine the time frame necessary to gain a compact bone capable of withstanding occlusal forces at the bone-implant interface.

Animals↗