PubMed Health⌕ Search

Biomedical subjects

H W Denissen

Publications and source records attributed to H W Denissen.

14 recordsLinked to original sources
PubMed1991

Dutch consensus on guidelines for superstructures on endosseous implants in the edentulous mandible.

This consensus report has been reached under the authority of the Dutch Society for Oral Implantology and the Dutch Society for Prosthetic Dentistry by a panel of Dutch dentists and prosthodontists (listed above) who are involved in the treatment of patients with oral implants, either via practice or via research. They were commissioned with a task to "formulate guidelines for the prosthetic treatment of edentulous patients receiving oral implants in the mandible".

Dental Implantation, Endosseous↗
PubMed1991

Preventive implantations.

Preventive implantology is concerned with the preservation of the alveolar ridge of the (edentulous) jaw. Maintaining the volume of the alveolar ridge is a major problem in the prevention of oral disease. Loss of teeth and tooth roots leads to resorption of residual ridges. This being so, it is a logical approach to substitute artificial analogues for lost tooth roots. Hydroxyapatite implants have been studied as submerged tooth root substitutes and shown to maintain the bulk of the alveolar ridge. A drawback of the implants is that the ridge maintenance depends solely on the physical presence of the hydroxyapatite implants. No physiological influence on bone preservation can be attributed to the implants. However, long term research indicates that 75 per cent of the implants survive under full lower dentures and 100 per cent of the implants under fixed partial dentures.

Alveolar Process↗
PubMed1990

[Classification of edentulous mandibles in preventive implantology].

The aim of preventive implantology is to prevent or delay the resorption of edentulous alveolar ridges. The classifications of the resorption stages of the mandible which are now in use, are not applicable to preventive implantology. After anatomic research it was concluded that the resorption of the alveolar ridge of the mandible should be classified in three stages. Loaded as well as unloaded implants can function as tooth root analogues in maintaining the volume of the edentulous ridge.

Alveolar Bone Loss↗
PubMed1989

Eleven-year study of hydroxyapatite implants.

An 11-year clinical research study was conducted with both unloaded bulk hydroxyapatite implants and loaded hydroxyapatite-coated titanium implants. A total of 102 submerged bulk hydroxyapatite implants were placed after extraction of teeth to maintain the volume of the residual alveolar ridge by their physical presence. All 21 implants under fixed partial dentures and 51 of 81 implants under lower complete dentures remained submucosal. A total of 71 hydroxyapatite-coated titanium implants were connected with permucosal superstructures by use of a two-stage method. Modifications in design and in implantation technique were required. This long-term research indicates that cylindrical hydroxyapatite implants are reliable devices as natural tooth root substitutes that bond directly to bone instead of simply being osseointegrated.

Dental Abutments↗
PubMed1989

[Implants with plasma spray coatings of hydroxyapatite: an experimental study in alveolar bone].

Sintered hydroxyapatite ceramic can be coated to a titanium core by means of a high temperature plasma spray procedure. The biological response of alveolar bone to an implant with such a coating of hydroxyapatite was evaluated in an animal experimental study. The results indicated that the plasma spray coating gave a very strong and direct bonding to cortical alveolar bone. The shear strength between bone and ceramic was greater than the shear strength between ceramic and titanium. From a radiological, macroscopic and microscopic point of view the conclusion could be drawn that the biological properties of a plasma spray coating of hydroxyapatite are the same as the properties of bulk hydroxyapatite ceramic. The outermost layer of the hydroxyapatite coating appeared to be unstable under the experimental conditions.

Animals↗
PubMed1979

Immediate dental root implants from synthetic dense calcium hydroxylapatite.

In this article, root implants implanted directly after extraction of the natural teeth were described. The root implants were made of densely sintered or hot-pressed calcium hydroxylapatite (CHA). The significance of using such implants as a method of preserving the bulk of the alveolar ridge and as possible anchoring sites for a post and core for fixed partial dentures was discussed.

Alveolar Process↗
PubMedDate not supplied

All porcelain anterior veneer bridges.

The introduction of new porcelain materials used in combination with vastly improved bonding materials and techniques have virtually revolutionized the use of conservative esthetic bonded prosthetic restorations fabricated without the need for metal substructures. Missing anterior teeth in selected cases may be replaced by all porcelain veneer bridges that are accomplished with more conservation of natural tooth structure of the abutment teeth as compared to traditional procedures. A total of 12 all porcelain veneer bridges were monitored for varying periods up to 24 months postoperatively, during which time no fractures occurred. The authors have attributed this high early success rate primarily to several factors, namely (1) case selection, (2) bulk of porcelain at the sides of the major connectors, and (3) adjustment of occlusion and articulation with the opposing teeth.

Composite Resins↗
PubMedDate not supplied

Preparation-induced stability of bioactive apatite coatings.

The stability of the bioactive surface is a major concern in the chemical and physical design of apatite ceramic coatings. In clinical studies, no sintered-hydroxyapatite bulk coating material was present in the surrounding bone tissue after loading periods up to 11 years. In in vitro studies, hydroxyapatite plasma-sprayed coatings dissolved considerably, possibly because of loss of crystallinity during the plasma-spraying procedure. A heat treatment at 600 degrees C reconstituted the crystallinity and promoted the transformation of alpha-tricalcium phosphate into the more stable beta-tricalcium phosphate. Fluorapatite coatings did not lose their crystallinity and had the added advantage of stability as a result of the fluoride ion.

Animals↗
PubMedDate not supplied

Mandibular bone response to plasma-sprayed coatings of hydroxyapatite.

Sintered hydroxyapatite ceramic particles can be applied as a coating on a titanium substrate using a plasma-spraying technique. The biological and mechanical properties of implants with such a coating were studied in the mandible of a dog. The results indicated that a very strong and direct bonding between the hydroxyapatite coating and the mandibular bone developed. The shear strength of the bone/ceramic interface was higher than the interfacial strength between ceramic and titanium substrate. From the radiologic, macroscopic, and microscopic observations it was concluded that the biological properties of plasma-sprayed coatings of hydroxyapatite are the same as those of sintered hydroxyapatite ceramic. As a result of mechanical failure of the coherence of the hydroxyapatite particles at the outer layer of the coating, free particles of hydroxyapatite were observed in the surrounding bone tissue.

Alveolar Process↗