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Biomedical subjects

M Helbo

Publications and source records attributed to M Helbo.

8 recordsLinked to original sources
PubMed2000

Osseointegration of subperiosteal implants using bovine bone substitute and various membranes.

An earlier study revealed incomplete osseointegration of individually made titanium subperiosteal implants covered by ePTFE membranes and fixated to the rabbit tibial bone surface. In addition, the newly-formed bone was dominated by large marrow spaces. In this subsequent study, subperiosteal implants were also fixated on the bone surface of both tibia of 9 Copenhagen White rabbits. Bio-Oss particles were packed densely covering the entire implant surface. One of 3 different membranes covered the implant and the particles. The membranes used were the degradable Polyglactin 910 mesh, a degradable bilayer collagen membrane and the non-degradable ePTFE membrane. Undecalcified sections were prepared for histologic evaluation after a 12 weeks' observation period. All 18 subperiosteal implants were completely osseointegrated. In addition, the marrow spaces were reduced compared to our previous study. The Bio-Oss particles proved to be biocompatible and osteoconductive. The ePTFE membranes revealed neither signs of collapse nor adjacent infiltration of inflammatory cells. The Polyglactin 910 mesh and the bilayer collagen membranes collapsed slightly. There were signs of resorption of the surface of the newly-formed bone under the degradable membranes. The cause of resorption can not be documented.

Animals↗
PubMed1995

Osseointegration of subperiosteal implant via guided tissue regeneration. A pilot study.

The principle of guided tissue regeneration was applied in an attempt to generate bone to cover a subperiosteal implant. Titanium frame works, casted on individual impressions of the anterior surface of the tibia of 4 Copenhagen White rabbits, were stabilized to the tibia by microscrews, and half of them were covered by an expanded polytetrafluoroethylene augmentation membrane. The observation period was 12 weeks. Guided bone regeneration partly covering the implants was seen at all experimental sides; on the control sides the implants were mainly embedded in fibrous tissue. Studies are in progress with the aim of reducing marked marrow space formation observed in all the regenerated areas.

Animals↗
PubMed1985

A differential diagnostic approach to the symptomatology of acute dental pain.

Seventy-four patients with acute pulpitis, apical periodontitis, marginal periodontitis, or pulpoperiodontitis were examined. A series of symptoms and signs was registered. Diagnostic specificities and sensitivities were calculated, and thirteen variables were subjected to discriminant analysis and log-linear multiway contingency table analysis. Pulpoperiodonitis was found inseparable from pulpitis on the basis of the registered symptoms and signs. Several symptoms and signs previously believed to have differential diagnostic power were found insignificant. The following combination of symptoms and signs yielded a correct diagnosis in 82.1% of the cases: constant pain, tenderness to temperature changes, "the tooth feels extruded," impaired mouth opening, tenderness to palpation in apical area, and mobility.

Dental Pulp↗
PubMedDate not supplied

Twenty-year experience with 12-unit fixed partial dentures supported by two abutments.

Eleven patients who had only two remaining natural teeth, vital mandibular canines, were treated using experimental 12-unit fixed partial dentures and complete maxillary dentures. The marginal bone support was 60% in one patient and 80% to 100% in the others. The patients were studied for 20 years. After 15 years, seven patients had prostheses that were still functional, two had prostheses that failed, one lost the prosthesis following treatment for oral cancer, and one patient died. Nine of the 22 abutments required endodontic treatment. After 15 years, the fixed partial dentures began to tilt distally and considerable resorption was found under the pontics. The periodontal tissues withstood the increased stress, and the prostheses were stable.

Adult↗