Biomedical subjects

Krister Nilner

Publications and source records attributed to Krister Nilner.

15 recordsLinked to original sources

PubMed2006

All-ceramic two- to five-unit implant-supported reconstructions. A randomized, prospective clinical trial.

The purpose of this study was to evaluate the clinical performance of two to five-unit implant-supported all-ceramic reconstructions and to compare the results of two different all-ceramic systems, Denzir (DZ) and In-Ceram Zirconia (InZ). Eighteen patients were treated with a total of 25 two- to five-unit implant-supported reconstructions. Nine patients were given reconstructions of the DZ system and the other nine reconstructions of the InZ system. The reconstructions were cemented with zinc phosphate cement onto preparable titanium abutments and were evaluated after 6 and 12 months. At the 12-month follow-up, all reconstructions were in function; none had fractured. Superficial cohesive (chip-off) fractures were, however, observed in 6 of the 18 patients (8 of 25 reconstructions). Nine units in the DZ group (in 7 of 13 reconstructions) and one in the InZ group (1 of 12 reconstructions) had chip-off fractures. The difference between the two groups regarding frequency of chip-off fractures was statistically significant (P < 0.01). Marginal integrity was rated excellent at 34 abutments (56%) and acceptable at 27 (44%). Results from this 12-month trial suggest that all-ceramic implant-supported fixed partial dentures of two- to five-units may be considered a treatment alternative. When comparing the two ceramic systems under study, however, this study concludes that the DZ system exhibits an unacceptable amount of veneering porcelain fractures and thus cannot be recommended for the type of treatment evaluated in this trial. Further studies and long-term follow-ups must be performed before the materials and technique can be recommended for general use.

Aluminum Oxide↗

PubMed2006

Specialisation and specialist education in prosthetic dentistry in Europe.

This presentation reports on the results of a meeting of prosthodontists from selected European countries. The aim of the meeting was to analyse and promote specialisation and specialist education in Prosthetic Dentistry in Europe. Representatives for Europe were selected from the European Prosthodontic Association (EPA) board, the Education and Research Committee of International College of Prosthodontists (ICP), countries with a legally recognised speciality, countries without a recognised speciality but organised training programmes and countries with neither of these situations. Data about specialisation and specialist training in Prosthodontics in Europe was scrutinised and discussed. The programmes for countries with specialist training had relatively similar content, mostly of three years duration. There was strong agreement that a recognised speciality raises the level of care within the discipline for both specialists and non-specialists. In several of the countries where a speciality had been introduced it had been initiated by pressure from public health planning authorities. The conclusions are that from a professional viewpoint an advancement of the speciality over Europe would develop the discipline, improve oral health planning and quality of patient care. A working group for harmonisation was recommended.

Education, Dental, Graduate↗

PubMed2005

Dimensions of oral health-related quality of life in an adult Swedish population.

The concept of oral health-related quality of life (OHRQOL) is investigated in this study. The aim was to explore the dimensionality of variables measuring OHRQOL in an adult Swedish population and to discuss the findings in relation to existing indices. The study was based on responses to a 1998 questionnaire sent to a random sample of 1974 persons aged between 50 and 75 years. There were 22 variables based on questions concerning oral situation and the impact on 7 theoretically different dimensions of QOL. The majority were satisfied with their oral health situation. During the previous 12 months, 16% of the population had experienced problems with their mouth or teeth on at least one occasion per mouth. Principal components analysis was used to analyze the dimensionality of the variables. Three factors accounted for 59% of the variance: (1) Physical and social disability, (2) psychological discomfort and disability, and (3) functional limitation and physical pain. The perception of OHRQOL is multidimensional, but the dimensions are not equally important. The dimensions of OHRQOL found in the present study are similar to those of existing instruments.

Adult↗

PubMed2005

Use of abutment-teeth vs. dental implants to support all-ceramic fixed partial dentures: an in-vitro study on fracture strength.

The aim of the present in-vitro study was to compare the fracture strength of all-ceramic Fixed Partial Dentures supported by tooth-analogues and periodontal membrane with the same supported by dental implants. As ceramics are highly brittle, they cannot withstand deformations of more than 0.1% without fracturing. Hence, when planning an all-ceramic FPD, it is essential to evaluate abutment support, as the fracture strength of all-ceramic constructions depends on the stability of the support to reduce strain in the beam of the prosthesis. The support provided by implants differs, however, from the support provided by natural teeth as the implants are anchored directly in the bone with no intermediate tissue. One question that arises is whether strain and stress in the prosthesis are lower when the prosthesis is loaded on implants compared to natural teeth and hence if all-ceramic FPDs benefit from implant support. Twenty-four three-unit all-ceramic FPDs-12 supported by two dental implants and 12 by two tooth-analogues serving as end abutments-were made. All FPDs were subjected to preloading in a preloading procedure and subsequently subjected to load until fracture occurred. Load at fracture were registered and comparisons between the two groups were made. The loads at fracture were statistically significant higher in the group supported by implants compared to the group supported by tooth-analogues (p = 0.003). Within the limitations of this in-vitro study, the following conclusions can be drawn: All-ceramic fixed partial dentures can be used in combination with dental implants. The solid support gained from implants might thus be beneficial for the outcome of such treatment due to decreased strain and stress levels in the prosthesis when loaded on implants compared to when loaded on natural teeth. Clinical studies are, however, needed to confirm these findings as there are more factors that influence the final clinical outcome.

Dental Abutments↗

PubMed2004

Implant-supported fixed prostheses in the edentulous maxilla. A 2-year clinical and radiological follow-up of treatment with non-submerged ITI implants.

OBJECTIVES: To evaluate the survival rate of non-submerged solid-screw ITI dental implants with a rough (titanium plasma sprayed, TPS) surface in the edentulous maxilla after 1 and 2 years of loading. MATERIAL AND METHOD: Twenty-five patients (mean age 64 years) with edentulous upper jaws received five-seven implants and, after a mean healing time of 6.9 months, screw-retained implant-supported fixed prostheses. A total of 146 ITI solid screw TPS implants were inserted. The diameter of 56% of the implants was smaller (3.3 mm) than the standard (4.1 mm) and the diameter of the rest (44%) was standard. The bone quantity of the majority of the patients was low and the bone quality poor. Clinical parameters were registered at baseline and at two annual follow-ups. Radiological examinations and assessments were also made at these times. RESULTS: Mean marginal bone level at baseline was measured at a point 4.52 mm (range 1.45-7.70, SD 1.2) apical of the reference point. Mean bone loss from baseline to 1 year of loading was 0.24 mm (SD 0.9, P=0.002) and from 1 year to 2 years of loading 0.15 mm (SD 0.4, P<0.001). Five implants failed, four of which were early failures prior to loading. One implant failed shortly after bridge installation. The cumulative survival rate was 96.6% after 1 and 2 years. CONCLUSION: ITI TPS solid-screw implants in combination with fixed prostheses had successful survival rates and were found to be a viable treatment alternative in the edentulous maxilla.

Adult↗

PubMed2003

On the accuracy of some in vitro models for mechanical studies of maxillary removable partial dentures.

OBJECTIVES: Comparative in vitro/in vivo studies show wide differences in functional strain magnitudes and patterns of functional strain distribution in prosthetic devices. The aim of this study was to evaluate the accuracy of three in vitro models for biomechanical studies of prosthetic devices. METHODS: Strain gages were attached to the test RPDs of six subjects. In vitro maxillary models with simple (model A), intermediate (model B) and advanced (model C) features for the anatomical simulation of supporting structures were manufactured for each subject. The dentures were subjected to two separate series of standardized functional and laboratorial loading tests. The principal maximum strain value (epsilon (1)) obtained for each gage and experiment was used to calculate the intra-experiment variance and inter-experiment variance for the in vivo and in vitro experiments. The integrated strain gage difference value between the in vitro and in vivo data (Sigma(diff)) was calculated for every loading test and compared to the in vivo inter-experiment variance with ANOVA and Scheffés test. RESULTS: The bite forces recorded were similar for each subject and loading position and between the two loading sessions. The inter- and intra-experiment variance was found to be higher for in vivo loadings than for in vitro. Results showed that the (Sigma(diff)) values for model B and model C were significantly different from the in vivo strain inter-experiment variance (p<0.05). SIGNIFICANCE: This study showed that the anatomical simulation of in vitro models is insufficient to allow for accurate mechanical analyses of maxillary RPDs and that only simple verifications of the strain levels in prosthetic appliances can be attained in vitro.

Aged↗

PubMed2002

Analysis of a device for assessment of abutment and prosthesis screw loosening in oral implants.

Screw loosening is an irritating problem in implant dentistry. Loosened abutment screws and prosthesis screws are often found at yearly examinations. Loosened screws may cause costly complications, such as screw fractures and fracture of the framework, and methods to prevent them would be welcome. The purpose of this study is firstly to describe a mechanical protractor device designed to fit the electrical Torque Controller (Nobel Biocare, DEA 020, Gothenburg, Sweden) and measure the number of degrees necessary to retighten the abutment screw or the prosthesis screw to reach the target torque value. A second purpose is to analyse the precision and validity of the device. The results of the study indicate that the degree of preset loosening of abutment and prosthesis screws can be well reflected in the number of degrees necessary for retightening. It was also shown that it is possible to retighten the abutment and prosthesis screws with a precision of 1.7 degrees and 1.3 degrees, respectively. The study shows that the device has good precision and validity. By using this device, we hope to be able to evaluate various parameters for screw stability, such as the type of implant system, the number of fixtures, the type of abutments, the type of bridge material and the need for retightening of the abutment and prosthesis screws.

Algorithms↗

PubMed2002

Contact allergy to gold is correlated to dental gold.

Questionnaire studies have indicated that patients with dental gold will more frequently have contact allergy to gold. This study aimed at investigating the relationship between contact allergy to gold and the presence and amount of dental gold alloys. A total of 102 patients were referred for patch testing because of suspicion of contact allergy. Patch tests were performed with gold sodium thiosulphate 2% and 5%. The patients underwent an oral clinical and radiological examination. Contact allergy to gold was recorded in 30.4% of the patients, and of these 74.2% had dental gold (p=0.009). A significant correlation was found between the amount of gold surfaces and contact allergy to gold (p=0.008), but there was no statistical relationship to oral lesions. It is concluded that there is a positive relationship between contact allergy to gold and presence and amount of dental gold alloys.

Adult↗

PubMed2002

Gold concentration in blood in relation to the number of gold restorations and contact allergy to gold.

Previous studies have demonstrated an association between gold allergy and the presence of dental gold restorations. The aim of the present study was to investigate the relationship between the concentration of gold in blood (B-Au) and the number of tooth surfaces with gold alloys in subjects with and without contact allergy to gold. In 80 patients referred for patch testing because of eczematous disease, blood samples were taken and analyzed for B-Au using inductively coupled plasma mass spectrometry. The detection limit for the Au determination was 0.04 microg/L. In addition, a dentist made a clinical and radiological examination of the patients and registered the number of dental gold surfaces. Patients with dental gold restorations had a statistically significantly higher B-Au in Mann-Whitney U test (P = 0.025), (range < 0.04-1.07 microg/L) than patients without (range < 0.04-0.15 microg/L). Furthermore, a positive correlation was found between B-Au and the number of dental gold surfaces (P < 0.01). There was no statistically significant difference in B-Au between persons with and without contact allergy to gold. The study thus indicates that gold is released from dental restorations and taken tip into the circulation.

Acrylic Resins↗

PubMed2002

Dental care utilization: a study of 50- to 75-year-olds in southern Sweden.

This study investigates dental care utilization in an adult population in Southern Sweden in relation to dental and social conditions, attitudes to costs, and perceived need to obtain dental services. The study was based on responses to a questionnaire sent in 1998 to a random sample, 1974 persons, aged 56-75 years. The response rate was 66%. A significantly higher probability of dental care utilization less than once a year was found for men, for those with few remaining teeth, and for those with removable dentures. A higher probability of dental care utilization less than once a year was found for those who stated perceived need to obtain dental care with no possibility because of the cost and for those who stated that the cost had influenced their attendance for dental care. The results showed that there were differences for sex and dental conditions in dental care utilization and that dental care utilization was related to attitudes towards costs of dental care.

Aged↗

PubMed2002

Quality of fixed prosthodontics after twenty-two years.

After an observation period of 22 years, this study was conducted to clinically examine and interview patients who in 1984 and 1989 had participated in similar investigations regarding the quality, over time. of treatments with fixed partial dentures. The patients were examined by two standardized and experienced clinicians using thc California Dental Association quality rating system, their results indicating that after 22 years the overall survival rates were 46.5% and 41.1% for the originally placed crowns and pontics, respectively. However, a continuing decrease of the crown quality rating was noted during the more than 20-year-long observation period. Restorative treatments with common types of fixed partial dentures can therefore be regarded as both safe and reliable over long periods of time.

Aged↗

PubMed2002

Early functional loading using Brånemark dental implants.

The present review article discusses the one- and two-stage surgical protocol for dental implant placement as well as the critical amount of micromotion at the bone-implant interface to obtain proper osseointegration. The relevant literature supporting the hypothesis that "splinting of individual implants as soon as possible following installation via a rigid fixed device will most likely decrease the micromotion at the bone-implant interface thus facilitating proper bone healing (osseointegration)" is reported. As a consequence of this approach, the treatment period can be significantly reduced. Finally, the importance of an objective evaluation of the bone quality and initial implant stability is highlighted. The information thus obtained via tools already available will facilitate the decision as to whether to load implants immediately, early, or late, and the term "individual functional loading" is coined.

Dental Implantation, Endosseous↗

PubMedDate not supplied

A prospective 5-year multicenter study of the Cresco implantology concept.

PURPOSE: The purpose of this study was to investigate the clinical and radiographic outcome of a prospective 5-year longitudinal multicenter test of a simplified implantology concept comprising an abutment-free implant system (Cresco) and a new method for fabrication of passively fitting superstructures, the Cresco Ti Precision method. MATERIALS AND METHODS: The tests were carried out at three different centers. Sixty partially or completely edentulous patients were restored by fixed implant-supported superstructures fabricated according to the Cresco Ti Precision method. In all, 215 Cresco implants were placed for the support of the superstructures. For various reasons, eight patients (13%) could not be followed through the 5 years. The radiographic measurements were recorded from radiographs exposed perpendicular to the implants. RESULTS: The initial implant failure rate (during the healing phase) was 2%, and the survival rate after loading was 98%. The mean peri-implant bone loss was 0.29 mm (SD 0.57). Of the measured sites, 71% showed a crestal bone loss of less than 0.5 mm. Very few mechanical complications were observed. This was attributed to the passively fitting superstructures. CONCLUSION: The results from the present multicenter test demonstrated that the abutment-free Cresco implantology concept is a reliable alternative method for implant-supported fixed prosthetic rehabilitation of edentulous and partially edentulous jaws.

Adult↗

PubMedDate not supplied

Immediately loaded implants supporting fixed prostheses in the edentulous maxilla: a preliminary clinical and radiologic report.

PURPOSE: To evaluate the survival rate of immediately loaded ITI sand-blasted, large-grit, acid-etched (SLA) solid-screw dental implants in the edentulous maxilla after 8 months of loading. MATERIALS AND METHODS: Twenty-eight patients (mean age 63 years) with edentulous maxillae each received 6 implants and 1 implant-supported fixed provisional prosthesis within 24 hours after surgery. After a mean healing time of 15 weeks, the patient received a definitive, screw-retained, implant-supported fixed prosthesis. A total of 168 implants were placed. Clinical parameters were registered after 1 month of loading with the implant-supported fixed prostheses as well as 8 months after implant placement. Radiologic examinations and assessments were made at implant placement and after 8 months. RESULTS: The mean marginal bone level at implant placement was 1.6 mm (range 0 to 5.1; SD 1.1) apical of the reference point (the implant shoulder). The mean marginal bone level at the 8-month follow-up was 3.2 mm (range 0.4 to 5.9; SD 1.1) apical of the reference point. Three implants failed during the healing period. DISCUSSION: The improved results in the present study might be a result of the positive effect of splinting the implants immediately after placement. CONCLUSION: ITI SLA solid-screw implants immediately loaded (ie, loaded within 24 hours of placement) and supporting fixed prostheses had successful survival rates after 8 months. The present results constitute a solid baseline for future follow-up studies.

Aged↗

PubMedDate not supplied

Attitudes toward the shortened dental arch concept among Swedish general dental practitioners.

PURPOSE: The purpose of this investigation was to obtain the opinions and assess the attitudes of Swedish general dental practitioners in private practice versus a public health care setting regarding management of patients with a shortened dental arch (SDA). MATERIALS AND METHODS: A questionnaire containing different statements regarding the SDA concept was sent to a random sample of 189 clinicians. Differences between male and female practitioners and between private practitioners (PPs) and those employed by the Public Dental Health Service (PDHS) were tested for statistical significance by the Student t test. RESULTS: The response rate was 54% (102 clinicians). Among the respondents, 62% were men and 38% were women. Fifty-six percent were PPs and 44% were employed by the PDHS. The results showed small differences in attitudes between various groups of practitioners but large individual variations. In general, Swedish general practitioners had a positive attitude toward the SDA concept with respect to oral function and oral comfort. They recognized few risks with a dentition lacking molar support, although female clinicians were more risk conscious. PPs expressed fewer advantages in using the SDA concept than PDHS practitioners with respect to the reduced risk for overtreatment, better patient economy, and the ability for older patients to keep their teeth. CONCLUSION: The results from this questionnaire study indicate that, overall, Swedish general practitioners have an affirmative opinion toward the SDA concept.

Attitude of Health Personnel↗