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Biomedical subjects

W Kalk

Publications and source records attributed to W Kalk.

At least 109 records · Page 6Linked to original sources
PubMed1984

Efficacy of 2.5% Pimafucin suspension in the treatment of denture stomatitis.

This double-blind clinical trial was carried out in 38 patients to compare the efficacy of 2.5% Pimafucin suspension with a placebo in the treatment of denture stomatitis. The diagnosis of Candida infection was confirmed by the making of cultures and microscopic examination. Data were analyzed from 32 patients, of whom 18 received Pimafucin suspension and 14 a placebo suspension. Pimafucin suspension-treated patients showed a significant reduction of Candida infection in terms of culture, culture growth, and number of colonies within the first week of therapy. There was no statistical evidence of relapse during the 4-week period after therapy was stopped. The group receiving a placebo failed to show any statistically significant improvement with respect to the mentioned parameters. Erythema of oral mucosa showed significant improvement in both groups. No side effects were found.

Adult↗
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

Use of implants for prosthetic rehabilitation after cancer treatment: clinical experiences.

Treatment of patients with head and neck cancer may result in extensive intra- or extra-oral defects. Prosthetic rehabilitation often will be limited by insufficient retention and an atrophic mucosa or skin. In such cases, osseointegrated implants may offer substantially improved retention for the often complex prosthetic constructions. However, irradiation has a negative influence on the bone growth capacity and thus on osseointegration. Based on experimental studies, a recovery period of 6 to 12 months after irradiation is recommended. Because of the risk of failure and the lack of sufficient and sound scientific knowledge, clinical studies of titanium implants inserted in previously irradiated bone tissue have had varying results. This paper discusses the typical requirements of implant suprastructures for resection prostheses. Some of the patient histories and clinical management presented illustrate the possibilities of implants in the field of maxillofacial reconstruction.

Aged↗
PubMedDate not supplied

Monitoring the polymerization process of acrylic resins.

Four groups of autopolymerizing acrylic resins used for various purposes in current dental practice were investigated by monitoring their temperature changes during the polymerization process. Resins were compared in terms of characteristic parameters (such as the time interval needed to reach mechanical stability and the maximum temperature generated during the polymerization process) and interpretations were made of such temporal temperature profiles.

Acrylic Resins↗
PubMedDate not supplied

Maxillary overdentures retained by splinted and unsplinted implants: a retrospective study.

The purpose of this retrospective study was to evaluate the clinical performance of and patients' satisfaction with maxillary overdentures retained by splinted and unsplinted implants. Patients who had been treated with maxillary implant-retained overdentures because of functional problems with conventional complete dentures were identified and invited to participate in the study. A total of 16 patients fulfilled the enrollment criteria and agreed to participate. Eleven patients were treated with bar-retained overdentures with 3 to 6 clips (mean follow-up 32 months), and 5 patients wore overdentures retained by 2 to 6 ball attachments (mean follow-up 54 months). All subjects were satisfied with their prostheses, and most subjects experienced improvement in their oral function after treatment with implant-retained overdentures. At the time of clinical examination, 92% (n = 77) of the 84 implants placed were functioning satisfactorily. The cumulative survival rate for the implants after 72 months was 90%. Loss of bone support correlated with peri-implant probing depth (r = 0.29; P < .02). No differences in mean bone loss between the subjects with ball-retained or bar-retained overdentures were found. The presence of plaque or peri-implant bleeding was not associated with the type of attachment.

Aged↗
PubMedDate not supplied

Patients with atrophic mandibles: opinions regarding the benefit of preprosthetic surgery.

This paper follows a previous report of an investigation regarding treatment of patients having atrophic mandibles. These patients either had surgery and received new dentures or received new dentures only. This paper reports the opinions of the patients concerning their treatment after an average of 6.5 years. The results showed that the patients in the group with atrophic mandibular ridges that were surgically treated were more generally satisfied with their dentures in comparison with the group of patients with atrophic ridges that were not surgically treated. The attitudes of the latter did not differ from the control group of patients having normal ridges.

Alveolar Bone Loss↗
PubMedDate not supplied

A comparison of different treatment strategies in patients with atrophic mandibles: a clinical evaluation after 6.5 years.

To gain more insight into the treatment strategies for edentulous patients with atrophic ridges, three groups of patients were evaluated: group 1, patients with atrophy of the mandible who needed preprosthetic surgery but who only received new dentures because surgery was contraindicated; group 2, patients in the same oral condition as those in group 1 who were treated with vestibuloplasty and lowering of the floor of the mouth before fabrication of new dentures; group 3, the control group of patients without residual ridge-related problems who were treated with new complete dentures. The differences between the three groups were evaluated 6.5 years after treatment. The results showed that the surface areas of the patients in group 2 were approximately 180% greater in the vestibular region and were 126% greater in the sublingual region, compared with the other groups. The stability of the mandibular dentures as well as the retention were better in group 2 than were those in group 1. Group 2 patients scored comparably or higher than the normal ridge group (group 3). The resistance against dislodgment of the denture was low in all three groups.

Aged↗
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

A study of acrylic resin denture base material distortion using computer-aided holographic interferometry.

A holographic interferometer for investigating deformations of dental prostheses is described. Residual stress relaxation resulting from the polymerization of acrylic resin dentures is qualitatively studied during the first 48 hours following fabrication. The resulting fringe patterns show a symmetry that is correlated to the shape of the denture. A quantitative analysis of the interferograms was performed with the aid of a computer program. The computer-aided holographic interferometer was tested using disk-shaped acrylic resin materials. Dimensional deformations resulting from temperature changes were measured with an accuracy better than 0.2 microns. Because of the aging of the resin material, the reaction to temperature changes may differ as a function of time and may be studied using quantitative comparison of deformation plots. For convenience, the original object shape can be added to or subtracted from the graphical deformation data.

Acrylic Resins↗
PubMedDate not supplied

Differences in oral stereognosis between complete denture wearers.

To better understand patients' relative satisfaction with complete dentures, differences in oral stereognostic perception, based on the identification of small objects placed in the mouth, were investigated. It was found that the oral stereognosis test applied is reliable for measuring patients' oral stereognostic perception. However, the positive correlation of other studies concerning the relationship between oral stereognosis and satisfaction with complete dentures was not confirmed in this study.

Adaptation, Psychological↗
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↗
PubMedDate not supplied

Occlusion for maxillary dentures opposing osseointegrated mandibular prostheses.

This paper presents a combination of several occlusal concepts designed to contribute to the successful use of maxillary dentures in opposition to osseointegrated mandibular prostheses. To ensure a positive outcome when designing such an occlusion, three factors must be considered: patient satisfaction, maxillary anterior bone preservation, and mandibular arch shortening. It is recommended that for centric occlusion the molars have a lingual contact occlusion, the premolars have a buccal contact occlusion, and the anterior teeth have an open occlusal relationship. For an eccentric occlusion, a balanced articulation is favored instead of mutually protected occlusion.

Dental Implants↗
PubMedDate not supplied

Influence of the dimensions of implant superstructure on peri-implant bone loss.

Two groups totaling 81 patients were selected. One group of edentulous patients had two IMZ implants, a bar, and an overdenture placed. The second group received a fixed restoration supported by one IMZ implant and one natural tooth. A superstructure constant was defined and used to combine the length and height of the Dolder bar or fixed prosthesis. Radiological bone loss was compared to the dimensions of the superstructure. The results showed a clear optimum for the dimensions of the superstructure on implants for the edentulous patient. Two implants connected with an overdenture should be placed 22 to 27 mm (between the centers of the implants) apart for best results. For fixed partial dentures no optimum dimensions could be found.

Alveolar Bone Loss↗