Reconstruction of the atrophic maxilla with interpositional bone grafting/Le Fort I osteotomy and endosteal implants: a 11-16 year follow-up.

A Le Fort I osteotomy and interpositional bone graft in combination with implants was used in the reconstruction of patients with extreme atrophy in their maxillae. Surgery was performed in a two-stage procedure. The patients in this study had conditions with reversed intermaxillary relationships with or without increased vertical intermaxillary distance. The aim of the study was to investigate treatment outcome for patients in a prospective, long-term, follow-up with a mean of 13 years (range 11-16 years), concerning implant survival rate and marginal bone loss adjacent to the surfaces of the implant. The impact of gender and smoking was also investigated. Twenty-six patients were included in the study. Of 167 implants, 24 failed. The implant estimated survival rate was 85% at the end of the follow-up. There was no significant difference between smokers and non-smokers or genders concerning implant survival. Marginal bone loss was 2.5, 2.9, 3.0 and 3.1mm from the implant-abutment junction, after 1, 2, 5 and 10 years, respectively. The bone level stabilised after 2 years. This technique results in good facial morphology, good oral function and aesthetics. All patients are still wearing their original fixed bridges.

Implants and/or teeth: consensus statements and recommendations.

In August 23-25, 2007, the Scandinavian Society for Prosthetic Dentistry in collaboration with the Danish Society of Oral Implantology arranged a consensus conference on the topic 'Implants and/or teeth'. It was preceded by a workshop in which eight focused questions were raised and answered in eight review articles using a systematic approach. Twenty-eight academicians and clinicians discussed the eight review papers with the purpose to reach consensus on questions relevant for the topic. At the conference the consensus statements were presented as well as lectures based on the review articles. In this article the methods used at the consensus workshop are briefly described followed by the statements with comments.

Double-quantum excitation in the NMR of spinning solids by pulse-assisted rotational resonance.

We describe a new technique for double-quantum excitation in magic-angle-spinning NMR of powdered solids. The technique is designed to efficiently excite double-quantum coherence in the vicinity of a rotational resonance condition. The offset from rotational resonance allows the double-quantum filtered signals to be observed with high resolution and sensitivity. The method uses rotational excitation of zero-quantum coherence, assisted by radiofrequency pulse cycles. The zero-quantum coherence is converted into double-quantum coherence by a frequency-selective inversion sequence. Experiments on [(13)C(2), (15)N]-glycine demonstrate a double-quantum filtering efficiency of approximately 41% at a sample rotation frequency of 8.300 kHz, which is 1.600 kHz away from the n = 1 rotational resonance. We achieve 32% double-quantum filtering efficiency at a spinning frequency of 9.250 kHz, which is 2.550 kHz away from rotational resonance.

Rigid connections between natural teeth and implants: a technical note.

In the posterior partially edentulous jaw, implants may be used to supplement existing natural dentition. Frequently, the maxillary sinuses and the mandibular nerve preclude the fabrication of freestanding implant-retained prostheses. However, if an implant and a natural abutment are combined, a fixed prosthesis can be fabricated, restoring the arch into the premolar area. The histories of three patients with attachments connecting implant-retained ceramotitanium crowns with crowns on natural abutments are described. A design for a rigid custom-made attachment for the Brånemark system, using standard components with a machine-duplication, spark-erosion technique, is suggested.

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.

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.

Bone grafts and Brånemark implants in the treatment of the severely resorbed maxilla: a 2-year longitudinal study.

A combination of horseshoe-shaped iliac bone grafts and Brånemark implants was used in 30 patients with severely resorbed maxillary alveolar ridges. All patients were followed clinically for 2 years and evaluated with regard to prosthesis stability, fixture survival, wound healing complications, and soft tissue conditions. Surgery was performed by the same oral surgeons using identical procedures, and the prosthetic treatment was performed by the same prosthodontist. The development group included the first 10 patients and the routine group included the following 20. Fixture survival in the development group was 54.4%, whereas 88.3% of the fixtures in the routine group have survived after 2 years. The average fixture survival in the study was 77.4%. Three patients in the development group lost all fixtures, primarily the result of trauma to the grafted region. With respect to the difficult situation many of these patients experienced, the survival rate should be considered most acceptable.

Functional loads on freestanding and connected implants in three-unit mandibular prostheses opposing complete dentures: an in vivo study.

In vivo measurements of vertical forces and bending moments during biting and chewing were carried out on 10 three-unit prostheses in the posterior mandibles of five patients. Each patient had two prostheses, one supported by two implants and the other supported by one implant and one tooth. The results demonstrated no major difference in functional load magnitudes related to the support type. The distribution of load between the abutments was influenced more by the prosthesis geometry and implant placement than by the difference in load characteristics of tooth and implant. This conclusion, however, is limited to one implant connected to a tooth, because multiple implants form a considerably stiffer unit than do teeth. An increase in vertical load resulting from cantilever extensions on the prostheses was documented, both at bite fork measurements and during chewing. No substantial lateral bending was registered, probably because the flat occlusal surfaces and the presence of the opposing complete denture reduced lateral forces.

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.

Survival of the Brånemark implant in partially edentulous jaws: a 10-year prospective multicenter study.

A total of 127 partially edentulous patients, treated according to the Brånemark protocol, was followed for 10 years after completion of prosthetic treatment. The patients ranged in age from 18 to 70 years, and 57% were female. Four hundred sixty-one implants were placed in 56 maxillae and 71 mandibles. In 125 patients, 163 fixed partial prostheses were attached to the implants; a majority of the prostheses (83%) were located in posterior regions. At the end of the 10-year period, 73% of the implants could be traced either as failed or in function, providing cumulative implant survival rates of 90.2% and 93.7% for the maxilla and mandible, respectively. Of the original fixed prostheses, 63% (cumulatively 86.5%) were still in use, whereas the level of continuous cumulative prosthesis function, including primary and remade restorations, was 94.3% at the end of the evaluation period. Marginal bone resorption at the implants was low (mean = 0.7 mm), and mucosal health was good. No severe complications apart from the above-mentioned implant and prosthetic failures were reported. The Brånemark Implant System is a safe and predictable method for restoring partially edentulous patients, as demonstrated by this 10-year follow-up investigation.

Interpositional bone grafting and Le Fort I osteotomy for reconstruction of the atrophic edentulous maxilla. A two-stage technique.

This study presents the results from ten consecutive patients who, because of insufficient bone volume for conventional implant placement in the maxilla, were treated with an interpositional bone graft and Le Fort I osteotomy. The endosteal implants were placed six months after the osteotomy. A total of 60 screw-shaped titanium implants (Brånemark) were placed, of which three failed to integrate during the six-month healing period. No further implants were lost during the follow-up period, ranging from 15 to 39 months after placement of the implants. All patients received fixed bridges and all have continued to function efficiently.

Bone grafting to the maxillary sinuses, nasal floor and anterior maxilla in the atrophic edentulous maxilla. A two-stage technique.

This study presents the results from 20 consecutive patients treated with an autogenous bone graft from the iliac crest. In ten patients the graft was placed in the maxillary sinuses and the floor of the nose (inlay group). Ten patients, in addition to the inlay graft, had a corticocancellous bone block secured with mini-screws to the anterior maxillary ridge (inlay/onlay group). Endosteal implants (Brånemark) were placed six months after surgery. A total of 136 implants were placed, of which eight failed to integrate during the six-month healing period. A further 15 implants were lost during the follow-up period. For the inlay group the average follow-up period was 22 months and for the inlay/onlay group 19 months. Donor site morbidity was significantly less when iliac bone was harvested with a trephine (inlay group) than in patients treated with our routine procedure for bone harvesting (inlay/onlay group). Surgical technique, donor site morbidity, implant survival and patient acceptance are presented.

10-year follow-up of onlay bone grafts and implants in severely resorbed maxillae.

Thirty patients with extremely resorbed maxillae had reconstructive bone grafts from the ala iliaca and endosseous implants in a one-stage procedure. The first ten patients constituted a development group and the following 20 patients a routine group. The marginal bone level and implants success rate was evaluated in a prospective long-term follow-up for a minimum of 10 years (10-13 years). Clinical and radiographic examinations were performed at 6 months and then annually up to 5 years. The final examinations were performed at the 10-year follow-up. The bridges were removed at every clinical examination. Marginal bone loss was seen up to the 3-year examination, where it averaged 4.6 mm in the routine group. Between the 3- and 10-year follow-up no significant change was registered. The initial bone loss was probably due to the design of the 3.6 mm conical unthreaded marginal part of the implant. The implant success rate was 83.1% in the routine group. Failures mostly occurred during the first 2 years (14 out of 20). A substantial amount of bone can be gained in patients with extremely resorbed maxillae, when treated with bone graft according to the procedure described in this study.

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)

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.

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.

A 9-14 year follow-up of onlay bone grafting in the atrophic maxilla.

Treatment of the atrophic edentulous maxilla is challenging especially when bone graft procedures are necessary. In this study an onlay bone graft, a saddle or veneer, with or without maxillary sinus floor inlay graft, harvested from the anterior iliac crest, in combination with implants was used in the reconstruction of patients with extreme atrophy in their maxillae. The aim was to investigate treatment outcome, and the impact of gender and smoking, in 44 patients in a prospective, long-term, follow-up study concerning implant survival rate and marginal bone loss adjacent to the surfaces of the implant. Mean follow-up time was 11 years. Of 334 inserted Brånemark implants, with machined surface, 27 failed. Estimated implant survival rate was 90%. Marginal bone loss was 1.8 mm 1 year after implant surgery; 2.3 mm after 5 years; and 2.4 mm after 10 years. There was a significant difference between genders in implant survival. Marginal bone loss differed significantly between smokers and non-smokers up to the 5-year examination and between genders after the 4-year examination. The onlay bone graft, with or without a maxillary inlay graft, results in high implant survival rate, good oral function and stabilised marginal bone. All patients are still wearing their original fixed bridges.

A 2-year clinical follow-up study of IPS Empress ceramic inlays.

This study evaluated the clinical quality of 62 Empress restorations placed for 18 patients. Patients were evaluated for caries and fracture by two investigators at 7 and 26 months using the CDA quality evaluation criteria in additional to periodontal criteria. The results indicated a large number of excellent ratings for color and surface, but lower ratings for anatomic form and marginal integrity.

Tooth- and implant-supported prostheses: a retrospective clinical follow-up up to 8 years.

PURPOSE: The purpose of this study was to evaluate clinical treatment outcome of fixed prostheses in different sizes and with combinations of different numbers of teeth and implants as abutments. MATERIALS AND METHODS: A total of 115 implants were placed in 36 patients, 75 (65%) in the maxilla and 40 (35%) in the mandible. The implants were connected to 85 abutment teeth, 50 in the maxilla and 35 in the mandible. Of the prosthetic restorations, 19 were gold ceramic, 17 were gold acrylic, three were titanium acrylic, one was titanium ceramic, and one was titanium composite. The observation period ranged from 14 months to 8.9 years. The treatments comprised both fixed partial dentures supported by one tooth and one implant as well as complete-arch fixed prostheses supported by a number of teeth and implants. RESULTS: A total of nine implants were lost, three during healing and six after loading. The postloading cumulative implant survival rate was 89.8% after 5 years. Five abutment teeth were lost, and of the 41 prostheses included in the study, only two (5%) were lost during the observation period. Marginal bone loss was registered around 46 implants at the 1-year follow-up examination. During the following observation period, only slight changes in the marginal bone level adjacent to the implants and teeth were registered. The magnitude of technical complications was low. CONCLUSION: This investigation confirms the findings in similar studies that treatments with periodontally healthy teeth and implants splinted together in rigid one-piece superstructures show excellent long-term follow-up results.

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.