| 1. |
- Anchieta, Rodolfo B., et al.
(författare)
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Mechanical Property Assessment of Bone Healing around a Titanium-Zirconium Alloy Dental Implant
- 2014
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Ingår i: Clinical Implant Dentistry and Related Research. - : John Wiley & Sons. - 1523-0899 .- 1708-8208. ; 16:6, s. 913-919
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundIt has been reported that titanium-zirconium alloy with 13-17% zirconium (TiZr1317) implants show higher biomechanical stability and bone area percentage relative to commercially pure titanium (cpTi) grade 4 fixtures. PurposeThis study aimed to determine whether the higher stability for TiZr1317 implants is associated with higher mechanical properties of remodeling bone in the areas around the implants. Materials and MethodsThis study utilized 36 implants (n=18: TiZr1317, n=18: cpTi), which were placed in the healed ridges of the mandibular premolar and first molar of 12 mini pigs (n=3 implants/animal). After 4 weeks in vivo, the samples were retrieved, and resin-embedded histologic sections of approximately 100m in thickness were prepared. In order to determine the nanomechanical properties, nanoindentation (n=30 tests/specimen) was performed on the bone tissue of the sections under wet conditions with maximum load of 300N (loading rate: 60N/s). ResultsThe mean (standard deviation) elastic modulus (E) and hardness (H) for the TiZr1317 group were 2.73 +/- 0.50GPa and 0.116 +/- 0.017GPa, respectively. For the cpTi group, values were 2.68 +/- 0.51GPa and 0.110 +/- 0.017GPa for E and H, respectively. Although slightly higher mechanical properties values were observed for the TiZr1317 implants relative to the cpTi for both elastic modulus and hardness, these differences were not significant (E=p>0.75; H=p>0.59). ConclusionsThe titanium-zirconium alloy used in this study presented similar degrees of nanomechanical properties to that of the cpTi implants.
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| 2. |
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| 3. |
- Cochran, David, et al.
(författare)
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A Comparison of Tapered and Nontapered Implants in the Minipig
- 2016
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Ingår i: International Journal of Oral & Maxillofacial Implants. - : Quintessence. - 0882-2786 .- 1942-4434. ; 31:6, s. 1341-1347
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Tapered implants are thought to result in equivalent long-term stability and marginal peri-implant bone height in comparison to cylindrical implants. The goal of this study was to compare the primary stability and osseointegration of a novel bone-level tapered-wall implant to a control bone-level cylindrical implant with exactly the same surface characteristics, in a direct side-by-side comparison in an animal model. MATERIALS AND METHODS: Mandibular premolars and first molars were extracted in 11 G.ttingen minipigs, and healing was allowed for 3 months. Six implants were placed with a 4-week surgical lag time between hemimandibles (three per side), and either immediately loaded (first implantation time point) or submerged (second implantation time point). Eight-mm-long × 4.1-mm-diameter titanium screw-type bone-level implants with tapered (two per side) and cylindrical bodies (one per side) were used (Institut Straumann); insertion torque and implant stability were measured, and the soft tissue was closed. Standardized radiographs were taken at implant placement and at sacrifice. Following a healing period of 1 month from the last surgical intervention (8 weeks total healing time for loaded implants; 4 weeks total healing time for nonloaded implants), the animals were sacrificed and mandibular blocks were harvested for nondecalcified histologic and histomorphometric analysis. RESULTS: All implants were integrated radiographically and osseointegrated histologically. Maximum insertion torque measurements and implant stability quotient values showed no significant difference between tapered and cylindrical implants. Histomorphometric analysis also resulted in comparable bone-to-implant contact values between the implant types and similarly limited marginal peri-implant bone resorption; no significant differences were observed regarding all the evaluated parameters between the groups, regardless of the loading regime. CONCLUSION: In a direct side-by-side comparison, in an intraoral minipig model, a novel bone-level tapered screw implant with an SLActive surface showed comparable clinical and histologic outcomes to a parallel-walled bone-level screw implant with an SLActive surface.
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| 4. |
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| 5. |
- Galli, Silvia, et al.
(författare)
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Chemically modified titanium-zirconium implants in comparison with commercially pure titanium controls stimulate the early molecular pathways of bone healing
- 2017
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Ingår i: Clinical Oral Implants Research. - : Blackwell Munksgaard. - 0905-7161 .- 1600-0501. ; 28:10, s. 1234-1240
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Titanium-zirconium (TiZr) has been proposed as a mechanically stronger alternative to commercially pure titanium for oral and orthopaedic implants. However, not much is known on the osseointegration kinetics of TiZr surfaces. In this study, we aimed to identify the genetic response of bone around TiZr implants compared to pure Ti. MATERIAL AND METHODS: Microtextured and hydrophilic TiZr implants (tests) and cpTi implants grade IV (controls) were placed in the tibia of 30 New Zealand white rabbits. At 2, 4 and 12 weeks, the implants were subjected to removal torque test (RTQ). The expression of a panel of genes involved in the process of osseointegration was measured in the bone around the test and control implants by means of quantitative real-time polymerase chain reaction (PCR) and compared to the control samples. RESULTS: The controls yielded statistically significant higher RTQ at 4 weeks, but the RTQ of the tests had a larger increase between 4 and 12 weeks, when both groups reached similar values. The gene expression analysis showed that all selected markers for bone formation, bone remodelling and cytokines were significantly upregulated around TiZr implants after 2 weeks. After 4 weeks of healing, two bone formation markers were significantly more expressed in the test samples, while at 12 weeks, the expression of all genes was similar in the two groups. CONCLUSIONS: TiZr implants showed comparable biomechanical outcomes to cpTi up to 12 weeks of healing. However, at early healing stages, they showed a significant upregulation of osteogenesis and osteoclastogenesis markers.
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| 6. |
- 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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| 7. |
- Jimbo, Ryo, et al.
(författare)
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Biomechanical and histomorphometrical evaluation of TiZr alloy implants : an in vivo study in the rabbit
- 2015
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Ingår i: Clinical Implant Dentistry and Related Research. - : John Wiley & Sons. - 1523-0899 .- 1708-8208. ; :suppl 2, s. e670-e678
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Clinically, there is a demand for mechanically stronger alloyed implants; however, not much evidence exists with regard to these materials. PURPOSE: To test the osseointegration property of TiZr1317 implants in a rabbit model. MATERIALS AND METHODS: Hydrophilic titanium-zirconium alloy (TiZr1317) implants with sand-blasted and acid-etched surface (test) and hydrophilic cpTi implants with the same treatment (control) were placed pairwise in the hind limbs (two in each tibia and one in each femur) of 36 Swedish lop-eared rabbits. After 2, 4, and 12 weeks (n = 12/time point), the bone samples were subjected to removal torque (RTQ, proximal tibia and femur) and histologic/histomorphometric (distal tibia) testings. RESULTS: The control presented significantly higher RTQ than the test at 2 weeks (55 vs 36 Ncm). No differences were observed for other time points. The test presented higher mean BIC than the control (19.25 vs 13.89 %) at 4 weeks; however, there were no statistical differences for the following time point tested in vivo.The new bone area was significantly higher for the test at 4 weeks in the marrow areas. CONCLUSION: The TiZr1317 implants presented comparable biologic outcomes to that of the cpTi implants through a 12-week evaluation period.
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| 8. |
- Miron, Richard J., et al.
(författare)
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Twenty years of enamel matrix derivative : the past, the present and the future
- 2016
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Ingår i: Journal of Clinical Periodontology. - : Blackwell Munksgaard. - 0303-6979 .- 1600-051X. ; 43:8, s. 668-683
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Forskningsöversikt (refereegranskat)abstract
- Background On June 5th, 2015 at Europerio 8, a group of leading experts were gathered to discuss what has now been 20years of documented evidence supporting the clinical use of enamel matrix derivative (EMD). Original experiments led by Lars Hammarstrom demonstrated that enamel matrix proteins could serve as key regenerative proteins capable of promoting periodontal regeneration including new cementum, with functionally oriented inserting new periodontal ligament fibres, and new alveolar bone formation. This pioneering work and vision by Lars Hammarstrom has paved the way to an enormous amount of publications related to its biological basis and clinical use. Twenty years later, it is clear that all these studies have greatly contributed to our understanding of how biologics can act as mediators for periodontal regeneration and have provided additional clinical means to support tissue regeneration of the periodontium. Aims This review article aims to: (1) provide the biological background necessary to understand the rational for the use of EMD for periodontal regeneration, (2) present animal and human histological evidence of periodontal regeneration following EMD application, (3) provide clinically relevant indications for the use of EMD and (4) discuss future avenues of research including key early findings leading to the development of Osteogain, a new carrier system for EMD specifically developed with better protein adsorption to bone grafting materials
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| 9. |
- Stavropoulos, Andreas, et al.
(författare)
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Effect of Osteotomy Preparation on Osseointegration of Immediately Loaded, Tapered Dental Implants
- 2016
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Ingår i: Advances in Dental Research. - : Sage Publications. - 0895-9374 .- 1544-0737. ; 28:1, s. 34-41
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present preclinical in vivo study was to evaluate whether a modified "drill-only" protocol, involving slight underpreparation of the implant site, may have an effect on aspects of osseointegration of a novel bone-level tapered implant, compared with the "standard drilling" protocol involving taping and profiling of the marginal aspect of the implant socket. In each side of the edentulated and completely healed mandible of 11 minipigs, 2 tapered implants (8 mm long × 4.1 mm Ø, BLT; Institut Straumann AG, Basel, Switzerland) were installed either with the drill-only or the standard drilling protocol. Significantly lower average insertion torque values were recorded for the standard drilling protocol group (52 ± 29 Ncm) compared with the drill-only group (70 ± 27 Ncm) (t test, P ≤ 0.05); no significant difference was observed between the 2 groups regarding implant stability, by means of resonance frequency analysis (75 ± 8 vs. 75 ± 6, respectively). Half of the implants were immediately loaded and the rest were submerged, providing observation times of 8 or 4 wk, respectively. Non-decalcified histological and histomorphometric analysis of the implants with surrounding tissues showed no significant differences between the 2 drilling protocols regarding the distance from the implant platform to the first coronal bone-to-implant contact (f-BIC), the total bone-to-implant contact (BIC) as a percentage of the total implant perimeter, and the bone density in an area extending 1 mm laterally from the implant (BATA) within 2 rectangular regions of interest (ROIs) 4 mm in height, representing the coronal (parallel-walled) and apical (tapered) aspect of the implant (ROI 1 and ROI 2, respectively) in non-submerged implants. In general, marginal peri-implant bone levels were at or slightly apical to the implant platform, and large amounts of bone-to-implant contact were observed. In contrast, immediately loaded implants placed with the drill-only protocol showed statistically significantly lower BIC values (66% ± 13.7%) compared with those installed with the standard drilling protocol (74.8% ± 11.2%) (P = 0.018). In addition, although marginal bone levels were in most of the immediately loaded implants at or slightly apical to the implant platform, some of the implants installed with the drill-only protocol showed marginal bone loss and crater formation. Thus, in this model system, even slight underpreparation of the implant socket appeared to compromise osseointegration of immediately loaded bone-level tapered implants.
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| 10. |
- Wennerberg, Ann, et al.
(författare)
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Nanostructures and hydrophilicity influence osseointegration : a biomechanical study in the rabbit tibia
- 2014
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Ingår i: Clinical Oral Implants Research. - : Wiley-Blackwell. - 0905-7161 .- 1600-0501. ; 25:9, s. 1041-1050
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveImplant surface properties have long been identified as an important factor to promote osseointegration. The importance of nanostructures and hydrophilicity has recently been discussed. The aim of this study was to investigate how nanostructures and wettability influence osseointegration and to identify whether the wettability, the nanostructure or both in combination play the key role in improved osseointegration. Materials and MethodsTwenty-six adult rabbits each received two Ti grade 4 discs in each tibia. Four different types of surface modifications with different wettability and nanostructures were prepared: hydrophobic without nanostructures (SLA), with nanostructures (SLAnano); hydrophilic with two different nanostructure densities (low density: pmodSLA, high density: SLActive). All four groups were intended to have similar chemistry and microroughness. The surfaces were evaluated with contact angle measurements, X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy and interferometry. After 4 and 8weeks healing time, pull-out tests were performed. ResultsSLA and SLAnano were hydrophobic, whereas SLActive and pmodSLA were super-hydrophilic. No nanostructures were present on the SLA surface, but the three other surface modifications clearly showed the presence of nanostructures, although more sparsely distributed on pmodSLA. The hydrophobic samples showed higher carbon contamination levels compared with the hydrophilic samples. After 4weeks healing time, SLActive implants showed the highest pull-out values, with significantly higher pull-out force than SLA and SLAnano. After 8weeks, the SLActive implants had the highest pull-out force, significantly higher than SLAnano and SLA. ConclusionsThe strongest bone response was achieved with a combination of wettability and the presence of nanostructures (SLActive).
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