| 1. |
- Zacharaki, E I, et al.
(författare)
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A digital subtraction radiography scheme based on automatic multiresolution registration.
- 2004
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Ingår i: Dento maxillo facial radiology. - : British Institute of Radiology. - 0250-832X. ; 33:6, s. 379-90
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To establish a digital subtraction radiography scheme for aligning clinical in vivo radiographs based on the implementations of an automatic geometric registration method and a contrast correction technique. METHODS: Thirty-five pairs of in vivo dental radiographs from four clinical studies were used in this work. First, each image pair was automatically aligned by applying a multiresolution registration strategy using the affine transformation followed by the implementation of the projective transformation at full resolution. Then, a contrast correction technique was applied in order to produce subtraction radiographs and fused images for further clinical evaluation. The performance of the proposed registration method was assessed against a manual method based on the projective transformation. RESULTS: The qualitative assessment of the experiments based on visual inspection has shown advantageous performance of the proposed automatic registration method against the manual method. Furthermore, the quantitative analysis showed statistical difference in terms of the root mean square (RMS) error estimated over the whole images and specific regions of interest. CONCLUSIONS: The proposed automatic geometric registration method is capable of aligning radiographs acquired with or without rigorous a priori standardization. The methodology is pixel-based and does not require the application of any segmentation process prior to alignment. The employed projective transformation provides a reliable model for registering intraoral radiographs. The implemented contrast correction technique sequentially applied provides subtraction radiographs and fused images for clinical evaluation regarding the evolution of a disease or the response to a therapeutic scheme.
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| 2. |
- Bergenholtz, Gunnar, 1939, et al.
(författare)
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Sveriges ledande position inom odontologisk forskning hotas
- 2003
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Ingår i: Tandläkartidn. ; 9, s. 60-61
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Nationella samordningsgruppens aktiviteter syftar till att: - identifiera forskningsmiljöer som kan stärkas genom nationell koordinering - sammanföra yngre forskare från olika forskningsmiljöer - sammanföra etablerade forskare men yngre forskare - stimulera till forskningssamarbete på ett nationellt plan
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| 3. |
- Brånemark, Per-Ingvar, et al.
(författare)
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Zygoma fixture in the management of advanced atrophy of the maxilla: technique and long-term results.
- 2004
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Ingår i: Scandinavian journal of plastic and reconstructive surgery and hand surgery / Nordisk plastikkirurgisk forening [and] Nordisk klubb for handkirurgi. - : Informa UK Limited. - 0284-4311. ; 38:2, s. 70-85
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Tidskriftsartikel (refereegranskat)abstract
- Despite refinements in surgical technique, including bone grafting and sophisticated prosthetic reconstructions, there are limitations to what can be achieved with bone-anchored fixed prostheses in patients with advanced atrophy of the maxillae. A new approach was suggested by a long-term study on onlay bone grafting and simultaneous placement of a fixture based on a new design: the zygoma fixture, and the aim of this study was to assess its potential. Twenty-eight consecutive patients with severely resorbed edentulous maxillae were included, 13 of whom had previously had multiple fixture surgery in the jawbone that had failed. A total of 52 zygoma fixtures and 106 conventional fixtures were installed. Bone grafting was deemed necessary in 17 patients. All patients have been followed for at least five years, and nine for up to 10 years. All patients were followed up with clinical and radiographic examinations, and in some cases rhinoscopy and sinoscopy as well. Three zygoma fixtures failed; two at the time of connection of the abutment and the third after six years. Of the conventional fixtures placed at the time of the zygoma fixture, 29 (27%) were lost. The overall prosthetic rehabilitation rate was 96% after at least five years of function. There were no signs of inflammatory reaction in the surrounding antral mucosa. Four patients with recurrent sinusitis recovered after inferior meatal antrostomy. To conclude, the zygoma fixture seems to be a valuable addition to our repertoire in the management of the compromised maxilla.
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| 4. |
- Ernberg, M, et al.
(författare)
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Examina och utbildning inom svensk odontologisk forskning
- 2003
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Ingår i: Tandläkartidn. ; 95:9, s. 54-59
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- En internationell utvärdering visade för några år sedan att Sverige riskerar att förlora sin position som världsledande nation inom odontologisk forskning. För att få en uppfattning om förändringarna inom forskarutbildningen och den postdoktorala meriteringen samlades data för 1990-2001 in från fakulteterna, Statistiska Centralbyrån samt Högskoleverket. Avsikten var att undersöka antalet forskarutbildade tandläkare, mångfalden bland doktoranderna och de som disputerat samt deras nuvarande anställningsform. Materialet jämfördes sedan med tidigare data. I medeltal avlade 25 personer per år doktorsexamen åren 1990-2001. Antalet har minskat under senare år. En majoritet av dem som avlade doktorsexamen hade odontologisk bakgrund. Relativt få har meriterat sig för en fortsatt akademisk karriär. 32 studerande påbörjade forskarutbildning åren 1991-2001. Andelen doktorander med annan akademisk grundexamen än odontologisk ökar. Sedan 1999 har forskningsvolymen minskat med motsvarande en hel fakultets forskningsvolym. Vi drar därför slutsatsen att kunskapsutvecklingen inom svensk odontologi riskerar att stagnera samt att fakulteternas behov av lärare till högre akademiska tjänster liksom folktandvårdens behov av handledare inom specialistutbildningen inte kommer att kunna tillgodoses i framtiden.
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| 5. |
- Friberg, Bertil, 1950, et al.
(författare)
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Long-term follow-up of severely atrophic edentulous mandibles reconstructed with short Brånemark implants.
- 2000
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Ingår i: Clinical implant dentistry and related research. - 1523-0899. ; 2:4, s. 184-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Oral implant treatment (Brånemark System) of edentulous mandibles has been presented in numerous studies. However, with regard to the severely atrophic lower jaw, no long-term follow-up studies with solely short implants are available. PURPOSE: The purpose of the present investigation was to retrospectively follow the long-term treatment outcome of patients with severely resorbed edentulous mandibles being subjected to oral implant placement with short (6-7 mm) Brånemark implants. MATERIALS AND METHODS: A total of 247 standard (7 mm long, Ø 3.75 mm) and 13 wide (6 mm long, Ø 5 mm) implants were inserted in 49 patients, all of whom exhibited severe resorption of edentate mandibles. Fixed implant-supported prostheses were manufactured for 45 patients, whereas 4 patients received overdentures. The patients were followed for a mean period of 8 years (range, 1-14 yr). RESULTS: Seventeen implants failed during the study period (cumulative implant survival rate 95.5% at 5-yr and 92.3% at 10-yr follow-up). Implant-supported constructions were worn continuously throughout the investigation by all study subjects. Marginal bone loss, measured after 1, 5, and 10 years of function, concurred with studies of Brånemark implants placed in more voluminous mandibles. No major clinical or construction complications occurred in the followed patients. CONCLUSIONS: The outcome of the present study showed that placement of short Brånemark implants without the use of bone grafting procedures for reconstruction of severely atrophic edentulous mandibles is a highly predictable treatment procedure.
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| 6. |
- Kahnberg, Karl-Erik, 1941, et al.
(författare)
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Sinus lifting procedure. I. One-stage surgery with bone transplant and implants.
- 2001
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Ingår i: Clinical oral implants research. - 0905-7161. ; 12:5, s. 479-87
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Tidskriftsartikel (refereegranskat)abstract
- A prospective study of one-stage surgery with intrasinus bone transplant and implants has been performed in 26 patients (13 males and 13 females). The aim of the study was to evaluate the success rate with the one-stage sinus lifting procedure in patients with a need for bony augmentation of the alveolar process. Fifteen patients were partially dentate and 11 edentulous. The mean height of the alveolar ridge was 2.5 mm preoperatively (range 1-5.5 mm). 126 fixtures were inserted, 93 in grafted bone and 33 in alveolar bone. Twenty-two patients have been followed for three years, 21 for four years and 11 for five years. The clinical overall survival rate was 69.6% although only 61.2% in grafted bone. Ten of the patients had varying degree of sinusitis post-fixture installation. At the end of the study, 23 patients had permanent bridges. The survival rate was low for inlay supported implants when the one-stage surgical technique was applied. Two-stage surgery may be a safer method.
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| 7. |
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| 8. |
- Wennström, Jan, 1947, et al.
(författare)
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Bone level change at implant-supported fixed partial dentures with and without cantilever extension after 5 years in function.
- 2004
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Ingår i: Journal of clinical periodontology. - 0303-6979. ; 31:12, s. 1077-83
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The aim of this study was to retrospectively analyze whether the inclusion of cantilever extensions increased the amount of marginal bone loss at free-standing, implant-supported, fixed partial dentures (FPDs) over a 5-year period of functional loading. MATERIAL AND METHODS: The patient material comprised 45 periodontally treated, partially dentate patients with a total of 50 free-standing FPDs supported by implants of the Astra Tech System. Following FPD placement (baseline) the patients were enrolled in an individually designed supportive care program. A set of criteria was collected at baseline to characterize the FPDs. The primary outcome variable was change in peri-implant bone level from the time of FPD placement to the 5-year follow-up examination. The comparison between FPDs with and without cantilevers was performed at three levels: FPD level, implant level, and surface level. Bivariate analysis was performed by the use of the Mann-Whitney U-test and stepwise regression analysis was utilized to evaluate the potential influence of confounding factors on the change in peri-implant bone level. RESULTS: The overall mean marginal bone loss for the implant-supported FPDs after 5 years in function was 0.4 mm (SD, 0.76). The bone level change at FPDs placed in the maxilla was significantly greater than that for FPDs in the mandible (0.6 versus 0.2 mm; p<0.05). No statistically significant differences were found with regard to peri-implant bone level change over the 5 years between FPDs with and without cantilevers at any of the levels of comparisons. The multivariate analysis revealed that the variables jaw of treatment and smoking had a significant influence on peri-implant bone level change on the FPD level, but not on the implant or surface levels. The model explained only 10% of the observed variance in the bone level change. CONCLUSION: The study failed to demonstrate that the presence of cantilever extensions in an FPD had an effect on peri-implant bone loss.
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| 9. |
- Wennström, Jan, 1947, et al.
(författare)
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Oral rehabilitation with implant-supported fixed partial dentures in periodontitis-susceptible subjects. A 5-year prospective study.
- 2004
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Ingår i: Journal of clinical periodontology. - 0303-6979. ; 31:9, s. 713-24
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Comparatively few studies with at least 5 years of follow-up are available that describe the use of implants in prosthetic rehabilitation of partially edentulous patients. Randomized, controlled clinical studies that evaluated the effect of different surface designs of screw-shaped implants on the outcome of treatment are also sparse. OBJECTIVE: To determine, in a prospective randomized, controlled clinical trial, the outcome of restorative therapy in periodontitis-susceptible patients who, following basic periodontal therapy, had been restored with implants with either a machined- or a rough-surface topography. MATERIAL AND METHODS: Fifty-one subjects (mean age, 59.5 years), 20 males and 31 females who, following treatment of moderate-to-advanced chronic periodontitis, required implant therapy for prosthetic rehabilitation were recruited. Seventeen of the patients were current smokers. Following the active treatment, all subjects were included in an individually designed maintenance program. A total of 56 fixed partial dentures (FPDs) and a total of 149 screw-shaped, and self-tapping implants (Astra Tech implants) -- 83 in the maxilla and 66 in the mandible -- were installed in a two-stage procedure. Each patient received a minimum of two implants and by randomization every second implant that was installed had been designed with a machined surface and the remaining with a roughened Tioblast surface. Abutment connection was performed 3-6 months after implant installation. Clinical and radiographical examinations were performed following FPD connection and once a year during a 5-year follow-up period. The analysis of peri-implant bone-level alterations was performed on subject, FPD and implant levels. RESULTS: Four patients and four FPDs were lost to the 5 years of monitoring. One implant (machined surface) did not properly integrate (early failure), and was removed at the time of abutment connection. Three implants were lost during function and a further eight implants could not be accounted for at the 5-year follow-up examination. The overall failure rate at 5 years was 5.9% (subject level), 5.3% (FPD level) and 2.7% (implant level). Radiographic signs of loss of osseointegration were not found at any of the implants during the 5-year observation period. During the first year in function there was on average 0.33 (SD, 0.61) mm loss of peri-implant marginal bone on the subject and FPD levels and 0.31 (0.81) mm on the implant level. During the subsequent 4 years, the peri-implant bone-level alterations were small. The calculated annual change in peri-implant bone level was -0.02 (0.15) on subject and FPD levels and -0.03 (0.20) on the implant level. Thus, the mean total bone-level change over the 5-year interval amounted to 0.41 mm on all three levels of analysis. In the interval between baseline and 5 years, the machined and the Tioblast implants lost on average 0.33 and 0.48 mm, respectively (p>0.05). CONCLUSION: The present randomized, controlled clinical trial that included partially edentulous periodontitis-susceptible subjects demonstrated that bone loss (i) during the first year of function as well as annually thereafter was small and (ii) did not vary between implants with machined- or rough-surface designs.
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| 10. |
- Åstrand, Per, 1935-, et al.
(författare)
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Astra Tech and Brånemark system implants: a 5-year prospective study of marginal bone reactions.
- 2004
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Ingår i: Clinical oral implants research. - : Wiley. - 0905-7161 .- 1600-0501. ; 15:4, s. 413-20
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the 5-year results of a comparative study between Astra Tech and Brånemark system implants. The aim was to compare the systems primarily with regard to bone level changes, and also with regard to other variables of interest. Sixty-six patients with edentulous jaws were included in the study. Randomisation schedules were used to allocate the patients to the two implant systems. 184 Astra Tech implants with a titanium-blasted surface and 187 Brånemark implants with a turned surface were used. The implants were inserted with a two-stage technique and the insertion followed the routines for the respective implant system. All patients were provided with full-arch fixed bridges. All patients were followed up with clinical and radiographic examinations from fixture insertion to the 5-year follow-up. The total mean bone level change in the upper jaw between fixture insertion and the 5-year examination was -1.74+/-0.45 mm at the Astra implants and -1.98+/-0.21 at the Brånemark implants. The corresponding values for the lower jaw were -1.06+/-0.19 for Astra and -1.38+/-0.17 for Brånemark. The major postoperative changes of the marginal bone level took place between fixture insertion and baseline. During this period, there was also a different pattern of bone remodelling between the implant systems. Between baseline (prosthesis connection) and the 5-year examination, the marginal bone level changes were small, with no difference between the implant systems. The implant stability was examined with the supraconstructions removed. At the 5-year examination, the survival rate for Astra Tech implants was 98.4% and for the Brånemark implants it was 94.6%. The difference was not statistically significant.
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