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Biomedical subjects

R M Meffert

Publications and source records attributed to R M Meffert.

At least 37 records · Page 2Linked to original sources
PubMed1996

Clinical evaluation of demineralized-unicortical-ilium-strips for guided tissue regeneration.

This study compared demineralized-unicortical-ilium-strips (DUIS) and an expanded polytetrafluoroethylene (ePTFE) physical barrier in combination with decalcified freeze-dried bone allograft (DFDBA) for treatment of Class II mandibular furcations. Twenty patients with adult periodontitis and at least 2 furcation invasions participated in this study. Probing depth (PD), clinical attachment level (CAL), and bone fill were measured at 6 and 12 months. Standardized radiographs were analyzed using computer assisted densitometric image analysis (CADIA). Fifteen of 20 patients completed the 12-month evaluation. At 6 months both control and test groups showed significant reductions in PD from baseline (P < 0.01). PD reduction for the ePTFE + DFDBA sites was 2.13 mm +/- 1.25, and the DUIS + DFDBA, 1.77 mm +/- 1.21. CAL at 6 months was sustained to 12 months when the net gains in CAL for ePTFE + DFDBA being 1.30 mm +/- 1.45 (P < 0.01) and for DUIS + DFDBA sites 1.13 mm +/- 1.68 (P < 0.02). The horizontal furcation PD decreased 2.87 mm +/- 1.68 (P < 0.01) in the ePTFE + DFDBA and 1.70 mm +/- 1.69 (P < 0.01) for DUIS + DFDBA sites over 12 months. The evaluation of the hard tissue response at the 12-month re-entry demonstrated a bone fill of 2.37 mm (75%) +/- 2.04 (P < 0.01) with ePTFE + DFDBA and 1.83 mm (79%) +/- 1.57 (P < 0.01) with DUIS + DFDBA. DUIS material and ePTFE showed significant improvements in clinical parameters and neither material proved to be significantly better. However, a larger sample size may have permitted us to demonstrate statistically significant differences between the materials. The positive results from the utilization of DUIS for GTR and the advantage of its bioresorbability warrant further investigation. The study found limitations in the use of CADIA for evaluation of guided tissue regeneration in furcations.

Absorptiometry, Photon↗
PubMed1995

Curriculum Guidelines in Implant Dentistry for Dental Hygiene Programs. Consensus Conference sponsored by the International Congress of Oral Implantologists, the American College of Oral Implantology, the American Society of Osseointegration, and the Association of Dental Implant Auxiliaries & Practice Management. Monterey, California, June 16, 1995.

A consensus conference to develop curriculum guidelines in implant dentistry for dental hygiene programs was held on June 16, 1995 in Monterey, California. The conference was sponsored by the International Congress of Oral Implantologists, the American College of Oral Implantology, the American Society of Osseointegration, and the Association of Dental Implant Auxiliaries & Practice Management. The guidelines, which will be distributed to dental hygiene program directors, are printed in their entirety.

Curriculum↗
PubMed1994

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.

Dental Implants↗
PubMed1993

Periodontitis and periimplantitis: one and the same?

Research shows that the same anaerobic, gram-negative pathogens are present in the periodontal and implant pocket or crevice. The implants in a partially edentulous case are probably more at risk due to the bacteria being more pathogenic and a seeding mechanism from the tooth pocket to the implant crevice. In the face of a normal microbial flora, retrograde periimplantitis or radiographic bone loss without gingival changes may be due to trauma because of overloading, loading too soon, and/or loading in a lateral direction. Finally, the combination of an infective process (periimplantitis) and noninfective or traumatic process (retrograde periimplantitis) will result in rapid osseous destruction and, possibly, loss of the implant fixture(s).

Alveolar Bone Loss↗
PubMed1993

Maxilla vs mandible: why use HA?

Various studies have shown that noncoated, metallic screw-type implants have been highly successful in types 1, 2, and 3 bone. However, in type 4 bone, such as that found in the maxilla, these implants have not been as successful. In the maxilla, HA-coated implants have shown better results than noncoated implants, particularly with regard to bone-to-implant contact, shear strength, and fixation. The author therefore concludes that the HA-coated implant may have better long-term success when shorter implants are needed, and when treating patients with poor, low density, and cancellous bone.

Animals↗
PubMed1993

Guided tissue regeneration around dental implants: three case reports.

This article demonstrates the use of guided tissue regeneration (GTR) principles for regeneration of bone tissue in jaw bone defects associated with dental implant placement. The learning objective of this article is the technique of bone tissue regeneration using the barrier membranes. Three cases are presented to illustrate the procedure. In all of them, the barrier membrane was used to cover the surgical site after the placement of dental implants and bone grafts.

Alveolar Bone Loss↗
PubMed1993

Light and confocal laser scanning microscopic evaluation of hydroxyapatite resorption patterns in medullary and cortical bone.

An animal study was conducted with unloaded blocks and hydroxyapatite (HA)-coated titanium implants. Four HA blocks were positioned in rabbit tibiae and four HA-coated titanium implants were positioned in pig tibiae. Implants were positioned so that half was placed in cortical bone and half in medullary space. Biopsy specimens were taken 4 months after implant placement for histologic evaluation. Light microscopy and confocal laser scanning microscopy demonstrated that the HA resorption rate was higher in the medullary spaces, whereas resorption was almost absent in the areas embedded in cortical bone.

Animals↗
PubMed1993

A proposed radiographic index for assessment of the current status of osseointegration.

The longevity of an osseointegrated implant is directly affected by the maintenance of its osseous anchorage. Progressive marginal bone loss would be detrimental to its survival. This article proposes a new radiographic index for use in the radiographic assessment of peri-implant marginal bone levels. The index scores range from 0 to 6 and denote marginal bone loss in percentages relative to the implant body length measured from its coronal-most margin in an apical direction. The proposed index should be of significance in: (1) use of short implants (7 to 10 mm); (2) evaluation of implants functioning in areas of low bone density (types 3 and 4); (3) prognosis and treatment of ailing/failing implants; (4) follow-up of implants placed in extraction sites; and (5) correlation of crown-to-implant ratio with marginal bone loss.

Alveolar Bone Loss↗
PubMed1993

Regeneration of dehisced alveolar bone adjacent to endosseous dental implants utilizing a resorbable collagen membrane: clinical and histologic results.

The purpose of this study was to evaluate the usefulness of resorbable collagen membrane for guided tissue regeneration. Dehiscences were surgically induced in dog mandibles. Hydroxyapatite-coated or grit-blasted implants were then placed in a random pattern in both sides of the mandibles (two of each type of implant in each side of the mandible). A resorbable collagen barrier membrane was placed around one pair of implants on each side. The other two implants on each side served as controls. The sites were examined clinically and histologically after 4 or 8 weeks to assess bone regeneration. Sites around experimental hydroxyapatite-coated and grit-blasted implants showed significantly more bone fill than did control sites. In addition to its apparent ability to encourage bone regeneration, the collagen membrane is resorbable, obviating the need for a second surgery to allow removal. (Int J Periodont Rest Dent 1993; 13:71-83.)

Alveolar Bone Loss↗
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↗