| 1. |
- Gottlow, Jan, 1951, et al.
(författare)
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Evaluation of a New Titanium-Zirconium Dental Implant: A Biomechanical and Histological Comparative Study in the Mini Pig
- 2012
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Ingår i: Clinical Implant Dentistry and Related Research. - : Wiley. - 1708-8208 .- 1523-0899. ; 14:4, s. 538-545
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Tidskriftsartikel (refereegranskat)abstract
- Background: Titanium zirconium alloy with 1317% zirconium (TiZr1317) shows significantly better mechanical attributes than pure Ti with respect to elongation and fatigue strength. This material may be suitable for thin implants and implant components exposed to high mechanical constraints. Purpose: The aim of this study was to test the hypothesis that TiZr1317 and Ti implants show comparable osseointegration and stability. Materials and Methods: The mandibular premolars (P1, P2, P3) and the first molar (M1) in 12 adult miniature pigs were extracted 3 months prior to the study. Six specially designed implants made from Ti (commercially pure, Grade 4) or TiZr1317 (Roxolid (R), Institut Straumann AG, Basel, Switzerland) with a hydrophilic sandblasted and acid-etched (SLActive, Institut Straumann AG, Basel, Switzerland) surface were placed in each mandible; three standard implants modified for evaluation of removal torque (RT) in one side and three bone-chamber implants for histologic observations in the contralateral side. RT tests were performed after 4 weeks when also the bone chamber implants and surrounding tissue were biopsied for histologic analyses in ground sections. Results: The RT results indicated significantly higher stability (p = 0.013) for TiZr1317 (230.9 +/- 22.4 Ncm) than for Ti implants (204.7 +/- 24.0 Ncm). The histology showed similar osteoconductive properties for both implant types. Histomorphometric measurements showed a statistically significant higher (p = 0.023) bone area within the chamber for the TiZr1317 implants (45.5 +/- 13.2%) than did the Ti implants (40.2 +/- 15.2%). No difference was observed concerning the bone to implant contact between the groups with 72.3 +/- 20.5% for Ti and 70.2 +/- 17.3% for TiZr1317 implants. Conclusion: It is concluded that the TiZr1317 implant with a hydrophilic sandblasted and acid-etched surface showed similar or even stronger bone tissue responses than the Ti control implant
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| 2. |
- Herrmann, Irene, 1950, et al.
(författare)
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A study on variances in multivariate analyses of oral implant outcome.
- 2007
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Ingår i: Clinical implant dentistry and related research. - : Wiley. - 1523-0899 .- 1708-8208. ; 9:1, s. 6-14
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Elaborate studies have shown that interdependency exists between implants being placed in the same patient/jaw. Therefore, interdependency ought to be an important aspect to address, whenever performing statistical analyses of oral implant outcomes. A Jackknife method could be an option when conducting statistical evaluations of oral implant failure prognoses. PURPOSE: The aim of this study was to evaluate whether a statistical difference can be detected by using the Jackknife method in conjunction with life table analyses and/or a log rank test of four different combinations of jaw density and quantity. MATERIALS AND METHODS: Four multicenter studies were pooled and adjusted in order to create a research database consisting of 486 patients and 1,737 implants in preparation for the Jackknife resampling method. Combinations of jaw shapes and bone qualities were constructed to select at-risk patients. STATISTICAL METHODS: Life tables with confidence intervals were calculated and a log rank test was used to determine whether a statistical difference between the combinations could be established. RESULTS: Both statistical analyses, after the Jackknife resampling method, showed that patients with poor bone quality and resorbed jaws (combination IV) had a statistically higher risk of implant failure. CONCLUSION: By rearranging data using the Jackknife method, standardized statistical tests seem to work well even when the study population tested was affected by interdependency.
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| 3. |
- Liljensten, E, et al.
(författare)
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Hydroxyapatite granule/carrier composites promote new bone formation in cortical defects.
- 2000
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Ingår i: Clinical implant dentistry and related research. - : Wiley. - 1523-0899 .- 1708-8208. ; 2:1, s. 50-9
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Tidskriftsartikel (refereegranskat)abstract
- A great deal of interest has been focused on finding substitutes for autogenous bone grafts. Among the most interesting materials are different calcium phosphate compositions (e.g., hydroxyapatite [HA]), due to their biocompatible properties in hard and soft tissue.
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| 4. |
- Meirelles, Luiz, 1974, et al.
(författare)
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Effect of hydroxyapatite and titania nanostructures on early in vivo bone response
- 2008
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Ingår i: Clinical Implant Dentistry and Related Research. - : Wiley. - 1708-8208 .- 1523-0899. ; 10:4, s. 245-254
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Hydroxyapatite or titania nano structures were applied on smooth titanium implant cylinders. The aim was to investigate whether nano HA may result in enhanced osseointegration compared to nano titania structures. Material and Methods: Surface topography evaluation included detailed characterization of nano size structures present at the implant surface combined with surface roughness parameters at the micro- and nano- meter level of resolution. Microstructures were removed from the surface to ensure that bone response observed was dependent only on the nanotopography and/or chemistry of the surface. Early in vivo bone response (4 weeks) evaluation was investigated in a rabbit model. Results: In the present study, nano titania coated implants showed an increased coverage area and feature density, forming a homogenous layer compared to nano HA implants. Bone response observed at 4 weeks could not be explained by the surface chemistry. New formed bone connected to the original cortical bone demonstrated an increase of 24% for the nano titania compared to the nano HA implant, although the difference was not statistically significant. Conclusion: Thus, no evidence of enhanced bone formation to nano hydroxyapatite modified implants was observed compared to nano titania modified implants. The presence of specific nano structures; dependent on the surface modification exhibiting different size and distribution did modulate in vivo bone response.
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| 5. |
- Albrektsson, Tomas, 1945, et al.
(författare)
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Survival of NobelDirect Implants: An Analysis of 550 Consecutively Placed Implants at 18 Different Clinical Centers
- 2007
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Ingår i: Clinical Implant Dental Related Research 9. - : Wiley. - 1523-0899. ; 9:2, s. 65-70
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A recently introduced implant, the NobelDirect (Nobel Biocare AB, Göteborg, Sweden), has previously been documented with substantial bone resorption in a large number of operated cases. PURPOSE: The aim of this study was to evaluate the failure rate of NobelDirect implants in a retrospective multicenter survey. MATERIALS AND METHODS: A total of 550 NobelDirect implants consecutively placed in over 269 patients at 18 centers were evaluated with regard to failure rate after an average follow-up of about 1 year. RESULTS: The overall failure percentage was 10.9% (59 failures). The 58 implants not loaded directly showed only one failure (1.7%) versus 58 failures (11.8%) of those implants that were loaded directly. A chemical x-ray photoelectron spectroscopy analysis of an implant from the original batch showed up to 3.5% silicon at parts of the implants. A retrieval analysis of one implant removed at 2 years after placement demonstrated bone resorption down to the level of the fifth thread. CONCLUSIONS: It is concluded that the NobelDirect implant, if placed with a punch procedure, ground down in situ, and loaded directly, shows an unusually high failure rate at 1 year.
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| 6. |
- Sjöström, Mats, et al.
(författare)
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Reconstruction of the atrophic edentulous maxilla with free iliac crest grafts and implants: a 3-year report of a prospective clinical study.
- 2007
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Ingår i: Clinical implant dentistry and related research. - : Wiley. - 1523-0899 .- 1708-8208. ; 9:1, s. 46-59
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The purpose of this study was to perform a longitudinal follow-up study of implant stability in grafted maxillae with the aid of clinical, radiological, and resonance frequency analysis (RFA) parameters. MATERIALS AND METHODS: The atrophic edentulous maxillae in 29 patients were reconstructed with free iliac crest grafts using onlay/inlay or interpositional grafting techniques. The endpoint of the resorption pattern in the maxilla determined the grafting technique used. Endosteal implants were placed after 6 months of bone-graft healing. Implant stability was measured four times using RFA: when the implants were placed, after 6 to 8 months of healing, after 6 months and 3 years of bridge loading. Individual checkups were performed at the two later RFA registrations after removal of the supraconstructions (Procera Implant Bridge, Nobel Biocare AB, Göteborg, Sweden). Radiological follow up of marginal bone level was performed annually. RESULTS: Twenty-five patients remained for the follow-up period. A total of 192 implants were placed and with a survival rate of 90% at the 3-year follow up. Women and an implant position with a class 6 resorption prior to reconstruction were factors with significant increased risk for implant failure (multivariate logistic regression). Twelve of the 20 failed implants were lost before loading (early failures). The change in the marginal bone level was 0.3 +/- 0.3 mm between baseline (bridge delivery) and the 3-year follow up. The implant stability quotient (ISQ) value for all implants differed significantly between abutment connection (60.2 +/- 7.3) and after 6 months of bridge loading (62.5 +/- 5.5) (Wilcoxon signed ranks test for paired data, p=.05) but were nonsignificant between 6 months of bridge loading and 3 years of bridge loading (61.8 +/- 5.5). There was a significant difference between successful and failed implants when the ISQ values were compared for individual implants at placement (Mann-Whitney U test, p=.004). All 25 patients were provided with fixed implant bridges at the time of the 3-year follow up. CONCLUSION: This clinical follow up using radiological examinations and RFA measurements indicates a predictable and stable long-term result for patients with atrophic edentulous maxillae reconstructed with autogenous bone and with delayed placement of endosteal implants. The ISQ value at the time of placement can probably serve as an indicator of level of risk for implant failure.
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| 7. |
- Abrahamsson, Ingemar, 1953, et al.
(författare)
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Healing at Implants Placed in an Alveolar Ridge with a Sloped Configuration: An Experimental Study in Dogs.
- 2014
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Ingår i: Clinical implant dentistry and related research. - : Wiley. - 1708-8208 .- 1523-0899. ; 16:1, s. 62-69
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To study healing around implants placed in an alveolar ridge with a sloped lingual-buccal configuration. Materials and Methods: Six Labrador dogs were used. Buccal bone defects were prepared in the mandible after extraction of premolars. Three months later, two test implants with a sloped marginal design and two control implants were placed in the chronic defect area with a sloped lingual-buccal configuration of each premolar region. The test implants were placed in such a way that the buccal margin of the implant coincided with the buccal bone crest. The lingual margin of the control implants was placed to a similar depth as the lingual margin of the test implants. Abutments were connected to the implants in the right mandibular premolar region and flaps were sutured around the neck of the abutments. In the left side of the mandible, cover screws were placed and the flaps were sutured to cover the implants. Biopsies were obtained 4 months later and prepared for histological examination. Results: It was demonstrated that healing around implants placed in an alveolar ridge with a sloped lingual-buccal configuration resulted in the preservation of a vertical discrepancy between the lingual and buccal marginal bone levels around implants with either a regular cylindrical outline or a modified marginal portion that matched the slope of the alveolar ridge. Conclusion: As the marginal buccal portion of the control implants with a regular design had no bone support, it is suggested that implants with a modified marginal portion may be considered in recipient sites with a sloped lingual-buccal configuration.
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| 8. |
- Abrahamsson, Ingemar, 1953, et al.
(författare)
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Tissue characteristics at microthreaded implants: an experimental study in dogs.
- 2006
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Ingår i: Clinical implant dentistry and related research. - : Wiley. - 1523-0899 .- 1708-8208. ; 8:3, s. 107-13
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The aim of the present study was to analyze bone tissue reactions at implants with and without a microthread configuration. MATERIALS AND METHODS: In six beagle dogs, one test and two control implants were installed in one side of the mandible. While both implant types had a similar dimension and surface roughness, the test implants were designed with a microthread configuration in the marginal portion. Abutment connection was performed after 3 months. Another 3 months later, fixed partial dentures (FPDs) were cemented to the maxillary canine and premolars and FPDs were connected to the implants in the mandible. Ten months later, the animals were sacrificed and biopsies from each implant region were processed for histological analysis. Radiographs were obtained at implant placement after FPD connection and at the termination of the experiment. RESULTS: The radiographic examination revealed that the marginal bone level was well preserved at both test and control implants during the entire 16-month period. The degree of bone-implant contact within the marginal portion of the implants was significantly higher at the test (microthread) implants (81.8%) than at the control implants (72.8%). CONCLUSIONS: It was suggested that the microthread configuration offered improved conditions for osseointegration.
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| 9. |
- Barone, Antonio, et al.
(författare)
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Maxillary Sinus Augmentation Using Prehydrated Corticocancellous Porcine Bone: Hystomorphometric Evaluation after 6 Months.
- 2012
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Ingår i: Clinical implant dentistry and related research. - : Wiley. - 1708-8208 .- 1523-0899. ; 14:3, s. 373-379
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Tidskriftsartikel (refereegranskat)abstract
- Background: Insufficient alveolar bone height often prevents the placement of standard dental implants in the posterior part of edentulous maxilla. In order to increase adequately the vertical dimension of the reabsorbed alveolar process, a sinus lift procedure is often necessary. The aim of this study was to evaluate histologic results of a prehydrated corticocancellous porcine bone used in maxillary sinus augmentation. Methods: Patients (age 18-70 years) with a residual bone height requiring a maxillary sinus augmentation procedure to place dental implants were eligible for this study. All patients were treated with the same surgical technique consisting of sinus floor augmentation via a lateral approach. The space obtained by elevation of the mucosa wall was grafted with prehydrated and collagenated corticocancellous porcine bone. Biopsies were harvested 6 months after the augmentation procedures. Results: Twenty-four patients were enrolled. The mean percentage of new formed bone was 43.9±18.6% (range 7.5-100%), whereas the mean percentage of residual graft material was 14.2±13.6% (range 0-41.9%). The new bone/residual graft material ratio in the maxillary sinuses was 3.1. The mean soft tissues percentage was 41.8±22.7% (range 0-92.5%). Conclusion: The present study suggested that porcine bone showed excellent osteoconductive properties and could be used successfully for sinus augmentation. Moreover, the porcine bone showed a high percentage of reabsorption after 6 months; this might be because of the presence of collagen and the porosity of the graft material.
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| 10. |
- Becker, William, et al.
(författare)
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300 years of experience.
- 2012
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Ingår i: Clinical implant dentistry and related research. - : Wiley. - 1708-8208 .- 1523-0899. ; 14:1, s. 1-2
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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