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Biomedical subjects

K Nilner

Publications and source records attributed to K Nilner.

At least 19 recordsLinked to original sources
PubMed1995

Removable partial denture design habits in general dental practice in Sweden.

An investigation was made concerning Swedish general dental practitioners' habits in removable partial denture design and their opinion of the undergraduate training programme in this matter. The investigation showed that many dentists failed to provide adequate prescriptions and that they relied heavily on the dental technician for partial dental design. A clear majority of the participants, educated at Umea dental school, considered the undergraduate training programme to be adequate, whilst a similar percentage educated at Gothenburg dental school was dissatisfied. The faculties in Stockholm and Malmo were placed between Umea and Gothenburg in this respect. The majority of the participants in this survey declared that the opportunity to attend small group postgraduate courses in the subject was desirable. A prerequisite for dentists to have control of the treatment they are responsible for, is that they at least have the necessary knowledge. This knowledge may have to be achieved after qualification instead of during their undergraduate training.

Attitude of Health Personnel↗
PubMed1994

Clinical and radiographical features of submerged and nonsubmerged titanium implants.

A clinical and radiographical study was performed to evaluate whether initial submergence of titanium fixtures is an obligate treatment measure for the establishment of proper bone anchorage when implants a.m. Brånemark are used. The sample was comprised of 11 subjects with edentulous mandibles. A split-mouth design was employed; in the right mandibular quadrant a traditional 2-step procedure for fixture installation and abutment connection was utilized, while in the left quadrant a 1-step procedure was carried out, i.e., fixtures were placed and abutments were connected in one and the same session. Three to 4 months after fixture installation, fixed bridgeworks were fabricated and rigidly connected to the implants. Clinical examinations (including probing pocket depth, bleeding on probing and implant stability test) were performed after 12 and 18 months. Radiographs were taken following insertion of the bridges and at the 12- and 18-month re-examinations. The probing pocket depth, the bleeding on probing, the implant stability and the radiographic determinations were similar for the 2 groups of treatment alternatives. This indicates that titanium fixtures a.m. Brånemark can be properly anchored (osseointegrated) in mandibular bone and successfully used for bridge retention also when a 1-step procedure is used for implant installation.

Adult↗
PubMed1994

Effect of selenium on mercury vapour released from dental amalgams: an in vitro study.

Wet corroded and air oxidized surfaces from different types of dental amalgams were used in this in vitro study. The mercury vapour released before and after standardized brushing with a conventional (ACTA) and an experimental selenium-containing toothpaste was examined. The results showed differences between the wet corroded and the air oxidized surfaces. High copper, non- gamma 2- amalgams, released more mercury vapour than the conventional one throughout the experiment. When the amalgam surfaces were brushed with the conventional toothpaste, an increase of the released vapour was noted. The use of the selenium containing toothpaste resulted in all cases, in significantly lower amounts of mercury vapour.

Analysis of Variance↗
PubMed1994

Long term clinical evaluation of three luting materials.

A last critical step in the completion of a cast restoration is permanent cementation. With the development of new luting agents the practitioner has to be aware of the physical and biological properties as well as the long term clinical performance of these materials. In this study three commonly used luting agents were evaluated over a four year period. The three cements, a zinc phosphate, a glass ionomer and a resin cement were tested for their reaction to periodontal tissues, pulpal response and other clinical parameters. In twenty six patients, 61 crowns, onlays or bridge abutments were cemented. Evaluations were made at 0 hour, after 7 days, 6 and 12 months and 4 years. In general the cements performed satisfactorily. Health of periodontal tissues adjacent to the crowns improved considerably after 7 days. Postcementation hypersensitivity appeared to be a negligible problem, which was attributed to the time span between preparation and cementation, which exceeded in most instances four weeks. The choice of a final luting agent should be based on anticipated postoperative pulpal reactions, rather than exclusive reliance on physical properties.

Analysis of Variance↗
PubMed1994

Clinical performance of three anterior restorative materials over 10 years.

The long-term performance of two chemically activated composite resins was compared to that of one silicate cement. Bulk and cavosurface marginal discoloration was evaluated with both an indirect photographic method and the direct US Public Health Service evaluation system. The results confirmed that composite resins had superior performance but higher secondary caries incidence than did silicate cements. The macrofilled composite resins showed better clinical performance than the microfilled restorations, as well as similar incidences of bulk and marginal discoloration. The agreement between the scores obtained with the direct evaluation criteria and those resulting from the indirect evaluation method was relatively poor. The indirect scores were usually the same or poorer than the direct clinical scores. The results indicated that the clinical evaluation may be the least sensitive of the two methods. The discrepancy in the scorings may, on the other hand, signify that the indirect photographic method records reflectance spectra that are not normally obtained in vivo.

Adolescent↗
PubMed1993

Effect of plasma treatment on the wettability of elastomeric impression materials.

This study investigated the effect of "plasma treatment" on the wettability of impression materials and void formation in die stone casts. Four addition reaction silicones, one condensation reaction silicone, and one polyether impression material were used. Wettability was determined before and after plasma treatment by contact angle registration of a saturated aqueous solution of calcium sulfate (CaSO4) on flat surfaces made from the tested impression materials. Two groups of surfaces were used for each material. The surfaces in one of the groups were exposed to saliva for 5 minutes. The same impression materials were used to produce four groups of die stone casts from a master die. Two groups were produced from impressions that had been exposed to milk. One group from the exposed and one from the bare surfaces were plasma-treated before pouring. Voids in the stone casts were counted under a stereoscopic microscope. The results indicated that after plasma treatment, the drop of CaSO4 solution completely spread over the addition type silicone surfaces. The corresponding die stone casts were found to be void free. It was concluded that plasma treatment produced high-energy impression surfaces that result in void-free die stone casts from the addition type silicone materials.

Adult↗
PubMed1993

A clinical and radiological two-year follow-up study of maxillary overdentures on osseointegrated implants.

In order to satisfy the need to restore the aesthetics, phonetics and comfort and to facilitate optimal hygiene procedures, 20 edentulous patients were treated with a new concept of overdenture therapy on implants and modum Brånemark. After 24 +/- 3.5 months the patients were re-examined. They were asked to answer a questionnaire and use a Visual Analogue Scale (VAS) to give their opinion on the prosthetic treatment. The results indicate that an implant-retained overdenture in the maxilla with this design can satisfy the patients needs in aesthetics, phonetics and comfort and can facilitate oral hygiene measures.

Aged↗
PubMed1993

Patient age and long term survival of fixed prosthodontics.

The possible relationship between patient age and the long term survival of fixed prostheses was studied in a randomised group of persons, who had received restorative treatment by general practitioners 15 years prior to this study. These fixed partial dentures had a mean extension of 6.9 units and a mean pontic/abutment ratio of 0.47. The group studied consisted of 77 persons who agreed to participate from an original group of 150 persons. Of the original group 20 had died, 17 were not traceable or unable to participate for medical reasons, and 36 declined to participate. The outcome of the treatment was compared between the following age subgroups (age as at the time of the original treatment) by division of the data at 37, 60 and 65 years. In these subgroups between 20 and 50 per cent of the prostheses had been lost or partially lost during the fifteen year period. Most of the failures and unacceptable quality ratings were found to be caused by fractures, loss of retention and/or dental caries. However, no systematic differences were found between any of the age subgroups studied.

Adult↗
PubMed1993

Quality of fixed prosthodontics after 15 years.

Interviews and/or clinical examinations by means of the California Dental Association quality evaluation system were carried out in a group of persons who had received extensive restorative treatments with fixed partial dentures 15 years before this study. The studied group consisted of 77 persons who agreed to participate from an original group of 150 persons selected at random from the Swedish Dental Insurance System records. Of the original group 20 had died, 17 were not traceable or not able to participate for medical reasons, and 36 declined to participate. Thirty-two per cent of the recorded reconstructions had been lost, and 8% partially lost during the 15-year period. Thirty-five per cent of the reconstructions were rated as Satisfactory, whereas the remaining ones had mixed clinical quality ratings. Failures and Not Acceptable quality ratings were found to be caused mainly by fractures, loss of retention, and/or dental caries.

Adult↗
PubMed1993

Long term clinical evaluation of conical crown retained dentures.

The conical crown was introduced by K.H. Körber more than twenty years ago, as a development of the well known telescopic crown. In combination with a removable denture, the conical crown has become widely used in Germany and Sweden, since the system enable modifications with maintained function if abutments are lost. All 78 patients treated with conical crown retained dentures, at the School of Dentistry, Dept. Prosthetic Dentistry, Lund University, 1983-1988, were included in a 40 month follow up study using the CDA quality evaluation system. More than 80% of the removable dentures and abutments were in function at the time of examination. Forty-four percent of the conical crown retained dentures were considered having acceptable quality while 56% were not acceptable, mainly due to caries at the abutments margins.

Aged↗
PubMed1992

Surface properties and castability of elastomeric impression materials after plasma cleaning.

The wettability of impression materials is an important requirement for accurate reproduction of intraoral structures. The aims of this study were to evaluate the effect of plasma cleaning on critical surface tension and die stone castability of five silicone impression materials. Critical surface tension was calculated using a contact angle analysis according to Zisman (1964), before and after plasma cleaning. Die stone casts were produced from impressions of a master die and the area extension of the reproduction was measured planimetrically. The results showed a general increase in the critical surface tension and in the polar force component of the composite free energy for materials treated with plasma cleaning. An improvement in castability of all materials was also noted.

Analysis of Variance↗
PubMed1992

Masticatory efficiency in individuals with natural dentition.

51 healthy dentate subjects aged between 20 and 60 years were evaluated with regard to their masticatory efficiency using a sieving test. A subjective evaluation of difficulty in chewing different kinds of food was also obtained by means of a questionnaire. The occlusal and restorative status were assessed using specific indices. The masticatory efficiency was shown to be lower with increasing age 20-39 years, mean = 39.8 and 40-60 years, mean = 27.1, respectively (p < 0.05). Males had a statistically significantly higher masticatory efficiency index than females. Multiple regression analysis showed that age, sex, the number of occluding teeth and the orthodontic treatment need index can predict half the variance in masticatory efficiency. It is concluded that it is more appropriate to describe masticatory efficiency with an average value for different age groups.

Adult↗
PubMed1991

Effect of a buffering sugar-free lozenge on intraoral pH and electrochemical action.

Two double-blind crossover studies were performed to test a sugar-free lozenge containing bicarbonate and phosphate buffers (Profylin). The studies were performed in groups of 20 and 13 individuals. In Study I active buffering or placebo lozenge (not buffered) was given, and the pH of plaque and saliva was measured after 2, 5, 10, 20, and 30 min. In study II the lozenges were given 10 min after a sucrose rinse, and both the pH and the potential and polarization of amalgam restorations that made contact in the oral cavity were measured. In study I both lozenges increased the pH of plaque and saliva, but the values after sucking on the active lozenge were significantly higher than after placebo. In study II a pH recovery of plaque and saliva after the sucrose rinse was recorded for both types of lozenge, but it was most pronounced for the active, buffering lozenge. A statistically significant difference was, however, found only 5 min after sucking on the lozenge. No influence on the current magnitude was observed. The results thus indicate that the buffering sugar-free lozenge raises the pH of plaque and saliva and accelerates the pH recovery after a sucrose rinse but seems to have no influence on the galvanic current magnitude of amalgam restorations in contact.

Buffers↗
PubMed1991

A new design for a hybrid prosthesis supported by osseointegrated implants: 2. Preliminary clinical aspects.

A fixed partial denture is preferred as a prosthetic restoration supported by tissue-integrated oral implants. However, there are occasions, especially in restoring an edentulous maxilla, when a fixed partial denture does not satisfy a patient's requirements for esthetics, good phonetics, proper oral hygiene, and oral comfort. A removable hybrid prosthesis attached to a bar that is conventionally fixed to tissue-integrated implants ad modum Brånemark was therefore designed to satisfy such needs and to meet requirements for splinting of the implants. Following the placement of prostheses, patients were asked to give their opinion on the comfort, phonetics, and esthetics of the prosthesis by marking a visual analog scale. The results indicate a successful initial outcome of the treatment.

Adult↗
PubMed1991

A new design for a hybrid prosthesis supported by osseointegrated implants: 1. Technical aspects.

Maxillary prosthetic restorations on osseointegrated implants are often problematic because of implant location, orientation, and need for lip support. A new design for a hybrid maxillary prosthesis that will provide good esthetics and phonetics, as well as ensure optimum conditions for oral hygiene and patient comfort, is proposed. The design includes separate support, lateral stabilization, and retention. Support is derived from elevated areas at the midline and on the extensions of a bar screwed to dental implants ad modum Brånemark. Lateral stabilization is obtained by a removable framework closely fitting the bar. Four precision attachments provide adjustable retention without influencing support. Technical aspects of the procedure are described.

Dental Implantation, Endosseous↗
PubMed1991

The functional deformation of maxillary complete dentures in patients with flabby alveolar ridges. Part I: Before surgery.

Using strain-guaged duplicate maxillary dentures, the deformation patterns and magnitude of functional strain were studied on five complete denture wearing subjects who had varying amounts of soft mobile tissue over their maxillary edentulous alveolar ridge so called flabby ridges. The thickness of mobile tissue--expressed as depth--was measured by a sharpened periodontal probe with aid of a plastic base plate as a locator. The functional test included maximum biting, and the chewing of three test food samples. The results did not point on any direct relationship between the thickness of the soft tissue and the midline deformation pattern and/or magnitude of functional strain. It seems, however, as if the main influence of mobile tissue is on the strain behaviour in the lateral part of the denture.

Aged↗
PubMed1991

The functional deformation of maxillary complete dentures in patients with flabby alveolar ridges. Part II: After surgery.

Using strain-gauged maxillary complete dentures, the effects of the surgical removal of soft mobile tissue over the maxillary edentulous alveolar ridges--flabby ridges--on the deformation pattern and magnitude of functional strain were studied in five subjects. The results showed that a 20-90% reduction in denture deformation had taken place after surgery. Furthermore, a pre-operative shear-straining pattern of the buccal flanges and the lateral palatal slopes was not evident post-operatively. The results of this study point on the beneficial value of early surgical removal of flabby maxillary alveolar ridges.

Aged↗