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Biomedical subjects

J Gunne

Publications and source records attributed to J Gunne.

11 recordsLinked to original sources

Vertical load distribution on a three-unit prosthesis supported by a natural tooth and a single Brånemark implant. An in vivo study.

In vivo bite forces, implant axial forces and bending moments were measured on 5 patients with fixed posterior prostheses supported by a natural tooth and a single Brånemark implant. The results demonstrate that the vertical loads applied to the prostheses are shared between the tooth and the implant. The maximum bending moment transferred to the implant (10-15 N.cm) was well below the acceptable load limits for the mechanical components (50-60 N.cm), even at bite forces exceeding 100 N. The main reason for this load sharing seems to be the inherent bending flexibility of the implant screw joint, which matches the axial flexibility of the periodontal ligament of the tooth.

Aged

Bridges supported by free-standing implants versus bridges supported by tooth and implant. A five-year prospective study.

The clinical question at issue, whether it is possible to combine implants and natural teeth via fixed bridges, is of current interest. The treatment of the subjects of this prospective study was performed between June 1984 and December 1986. This article presents the 5-year results of the study. The consecutive patient material comprised 23 patients with Applegate Kennedy Class I residual dentition in the mandible and a complete maxillary denture. All 23 patients were provided with implants ad modum Brånemark in each mandibular quadrant. One side was randomized to rehabilitation with fixed bridge between the distal tooth of the residual dentition and an implant; the other side received a free-standang bridge on 2 implants. The fixture survival rate was 88%. No difference was found between the two sides. Bridge stability was 89% for the implant bridges and 91% for the combination bridges. The change in marginal bone level at the implants was small during the 5-year follow up period (on average 0.1-0.3 mm) and with no difference between the two sides. In conclusion, it was not possible to demonstrate any higher risk of implant or prosthetic failure for tooth-implant fixed bridges compared with implant-supported bridges.

Alveolar Bone Loss

Mechanical aspects of a Brånemark implant connected to a natural tooth: an in vitro study.

Mechanical in vitro tests of the Brånemark implant disclose that the screw joint which attaches the prosthetic gold cylinder and the transmucosal abutment to the fixture forms a flexible system. This inherent flexibility seems to match well the vertical mobility of a supporting tooth connected to the implant. Calculations of vertical load distribution based on measured flexibility data demonstrate that the forces are shared almost equally between tooth and implant even without taking the flexibility of the surrounding bone or the prosthesis into account. The therapy of a single Brånemark implant connected to a natural tooth should be considered without any additional element of a flexible nature. Mechanical tests and theoretical considerations, however, indicate that the transverse mobility of the connected tooth should be limited and that the attachment of the prosthesis to the tooth should be of a rigid design to avoid gold-screw loosening.

Dental Abutments

Combination of natural teeth and osseointegrated implants as prosthesis abutments: a 2-year longitudinal study.

Twenty-three patients with Kennedy Class I mandibular dentition were supplied with prostheses in the posterior parts of the mandible. On one side they were given a prosthesis supported by two implants (prosthesis Type I) and on the other side they received a prosthesis supported by one implant and one natural tooth (prosthesis Type II). Sixty-nine fixtures were inserted and 46 prostheses constructed. Eight of the fixtures were lost during the observation period. The failure rate of the implants was about the same in the two types of prostheses; five fixtures belonged to prostheses Type I (10.9%) and two fixtures belonged to prostheses Type II (8.7%), while one fixture was lost prior to loading. From a theoretical point of view, the combination of a tooth and an osseointegrated implant should encounter problems with regard to the difference in bone anchorage and there should be a risk of biomechanical complications. However, the results of this study did not indicate any disadvantages in connecting teeth and implants in the same restoration.

Adult

Osseointegrated implants in edentulous jaws: a 2-year longitudinal study.

Osseointegrated implants in 50 edentulous jaws were studied during a 2-year observation period. The implant survival rate was 89% in the maxillae and 97% in the mandibles. The marginal bone loss averaged 1.7 mm in the maxillae and 1.1 mm in the mandibles. Most of this bone loss occurred during the first year. The bone loss was greater in jaws with a preoperatively minor resorption of the alveolar ridge than in those with moderate or advanced resorption. The bone loss was also greater at the medially positioned implants than at those more posterior.

Adult

Impression technique for RPDs. A comparison between two methods.

The purposes of this study were threefold, 1) to develop a method for comparing various impression techniques and materials, 2) to compare the extension of impressions with ZOE-paste and silicone, and 3) to evaluate the precision for each method. A special device was constructed in order to secure an identical position of the impression trays. The results indicated that ZOE-paste impression in a border moulded tray produced more extended impressions lingually but buccally there were no difference between the chosen materials/method. No differences in precision of the two methods could be measured.

Dental Impression Materials

Opinions and wearing habits among patients new to removable partial dentures. An interview study.

Thirty-five patients treated at the Department of Prosthetic Dentistry, University of Umeå, who had received removable partial dentures (RPD) during the period July 1st 1981 to December 31st 1982, were interviewed regarding the use and experiences of their dentures. None of the patients had previously used an RPD. The treatment had been carried out by dentists and dental students. At the time of the interview, 1-2 1/2 years after receiving the prosthesis, 34 subjects (97%) declared that they used their RPDs during various parts of the day.

Adult

Masticatory ability in patients with removable dentures. A clinical study of masticatory efficiency, subjective experience of masticatory performance and dietary intake.

One of the functions of the masticatory system is to grind the food, salivate and prepare it for swallowing. Individuals who have lost many teeth or wear removable dentures, both complete and partial, find it more difficult to grind food i.e. they suffer from impaired masticatory efficiency (ME). Some of these subjects have to avoid food-stuffs which are hard and difficult to chew. This could influence the social well-being and may eventually lead to an increased risk of malnutrition. Many different methods have been used to evaluate ME. In most of them the degree to which the masticated food or test material was broken down was measured by fractionating the particles in a sieve system. However, one of the purposes of chewing the food is to enlarge the surface area to be exposed to the digestive juices. A few authors have applied this idea and have calculated ME using the summarized area of the masticated test material. This is physiologically a more correct method. ME was investigated in 19 complete denture wearers who were fitted with new dentures. The subjects were tested twice with the old dentures and 5 times with the new ones. The last test took place about 18 months after insertion of the new dentures. The test material was gelatin hardened with formalin. The breakdown of test material was calculated by fractionating it in a sieve system. ME was also evaluated in two other groups, 43 complete denture wearers, who were in need of new dentures, and 19 subjects who were in need of RPDs in the lower jaw. In these two studies ME was evaluated in two ways. Firstly the summarized area of masticated gelatin particles was calculated and used as a measure of ME. Secondly almonds were used as test material and the breakdown was calculated by fractionating in a sieve system. The subjects were tested on three occasions, before prosthetic treatment and about one and four months after insertion of the dentures. On the first and last occasions the subjective experience of masticatory performance was assessed as well as the dietary intake. The results revealed no systematic change in ME when the 19 subjects were fitted with new complete dentures and when the breakdown of the test material was evaluated by fractionating it in a sieve system.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent

Bone grafts and implants in the treatment of the severely resorbed maxillae: a 3-year follow-up of the prosthetic restoration.

Thirty patients with severely resorbed maxillae were treated in a one-stage procedure using bone graft and implant placement. A horseshoe-shaped bone graft was taken from the iliac wing and fixed to the residual maxillary ridge using titanium implants, which supported the prostheses placed after a 6-month healing period. The material constituted two groups: a development group, the first 10 patients; and a routine group, the following 20 patients. At the 3-year follow-up, the implant survival was 87.5% and the prosthesis stability was 100% in the routine group. The probing depth did not change during the follow-up period, while the grafted region decreased in volume during the first postoperative year. The patients reported improved chewing ability and improved life quality. Very few technical and prosthodontic complications occurred.

Adult

Implant treatment in partially edentulous patients: a report on prostheses after 3 years.

There has been an increasing interest in the use of implants for partially edentulous patients. This introduces other biomechanical situations than those experienced in completely edentulous patients. In a prospective multicenter study, 521 implants in 154 patients were loaded with 197 free-standing prostheses. The patients have been followed for 3 years. The cumulative success rate for the prostheses was 94.8% and for the implants it was 93.9%. Most of the lost prostheses were only supported by two implants. A frequent technical complication was fracture and loosening of gold screws, which was more frequent in prostheses supported by only two implants.

Adolescent