32 research outputs found
Productivity of reed (Phragmites australis Trin. ex Steud.) in continental-arid NW China in relation to soil, groundwater, and land-use
Reed (Phragmites australis Trin. ex Steud.) is a cosmopolitan plant species which can build up large stands in wetlands, floodplains, and on sites where groundwater is available. Phragmites australis provides many ecosystem services, such as the production of raw material (e.g. house construction or organic fuel). In the desert regions of Central Asia, reed occurs along river, e.g. the Tarim, Syr Darya, Amu Darya, and serves as fodder plant and raw material for construction and paper production. In those arid regions, reed occurs on submerged sites as well as non-flooded sites in a wide variety of phenotypes, ranging from so-called „giant reed“ (2-4 m high) to dwarf-like thorny reed not exceeding 40 cm stem length. We investigated the net primary production of the different phenotypes and their distribution with regard to soil and groundwater salt content and regarding grazing. The phenotypes were characterized through stem length, stem diameter, number of leaves per stem length, leaf weight ratio, leaf length, and leaf width. The net primary production reached 6,004 kg/ha·a on a non-grazed site, which is submerged for one month in late summer. The depth of the closed capillary fringe before onset of the flood was 2.2 m. The electric conductivity at the closed capillary fringe (determined from a water saturated soil extract) was 2 mS/cm. Stem length and stem diameter did not decrease with increasing soil and groundwater salt content, as expected. Conversely, stem length and stem diameter decreased and leaf weight ratio increased with increasing grazing intensity. Thus, grazing turned reed into dwarf-like thorny phenotypes. Non-grazed reed stands are the most productive ecosystems of the riparian vegetation at the Tarim and have a high potential to be used as raw material plant. We conclude that biomass harvesting could be an alternative to grazing with regard to sustainable land use
Clinical and radiographic outcomes of zirconia dental implants-A systematic review and meta-analysis.
peer reviewed[en] OBJECTIVES: For the present review, the following focused question was addressed: In patients with root-analog dental implants, what is the effect of implants made of other materials than titanium (alloy) on implant survival, marginal bone loss (MBL), and technical and biological complications after at least 5 years.
MATERIALS AND METHODS: An electronic (Medline, Embase, Web of Science) search was performed to identify observational clinical studies published from January 2000 investigating a minimum of 20 commercially available zirconia implants with a mean follow-up of at least 60 months. Primary outcome was implant survival, secondary outcomes included peri-implant MBL, probing depths (PDs), and technical and biological complications. Meta-analyses were performed to evaluate implant survival, MBL, and PD.
RESULTS: From 5129 titles, 580 abstracts were selected, and 111 full-text articles were screened. Finally, 4 prospective and 2 retrospective observational clinical cohort studies were included for data extraction. Meta-analyses estimated after 5 years of loading mean values of 97.2% (95% CI 94.7-99.1) for survival (277 implants, 221 patients), 1.1 mm (95% CI: 0.9-1.3) for MBL (229 implants, 173 patients), and 3.0 mm (95% CI 2.5-3.4) for PDs (231 implants, 175 patients).
CONCLUSIONS: After 5 years, commercially available zirconia implants showed reliable clinical performance based on survival rates, MBL, and PD values. However, more well-designed prospective clinical studies and randomized clinical trials investigating titanium and zirconia implants are needed to confirm the presently evaluated promising outcomes
The effect of different abutment materials on peri-implant tissues-A systematic review and meta-analysis.
peer reviewed[en] OBJECTIVES: In patients with dental implants, what is the effect of transmucosal components made of materials other than titanium (alloys) compared to titanium (alloys) on the surrounding peri-implant tissues after at least 1 year?
MATERIALS AND METHODS: This systematic review included eligible randomized controlled trials identified through an electronic search (Medline, Embase and Web of Science) comparing alternative abutment materials versus titanium (alloy) abutments with a minimum follow-up of 1 year and including at least 10 patients/group. Primary outcomes were peri-implant marginal bone level (MBL) and probing depth (PD), these were evaluated based on meta-analyses. Abutment survival, biological and technical complications and aesthetic outcomes were the secondary outcomes. The risk of bias was assessed with the RoB2-tool. This review is registered in PROSPERO with the number (CRD42022376487).
RESULTS: From 5129 titles, 580 abstracts were selected, and 111 full-text articles were screened. Finally, 12 articles could be included. Concerning the primary outcomes (MBL and PD), no differences could be seen between titanium abutment and zirconia or alumina abutments, not after 1 year (MBL: zirconia: MD = -0.24, 95% CI: -0.65 to 0.16, alumina: MD = -0.06, 95% CI: -0.29 to 0.17) (PD: zirconia: MD = -0.06, 95% CI: -0.41 to 0.30, alumina: MD = -0.29, 95% CI: -0.96 to 0.38), nor after 5 years. Additionally, no differences were found concerning the biological complications and aesthetic outcomes. The most important technical finding was abutment fracture in the ceramic group and chipping of the veneering material.
CONCLUSIONS: Biologically, titanium and zirconia abutments seem to function equally up to 5 years after placement
Group 3 ITI Consensus Report: Materials and antiresorptive drug-associated outcomes in implant dentistry
Objectives: The aim of Working Group 3 was to address the influence of both material- and anti-resorptive drug- related factors on clinical and biological outcomes
and complications in implant dentistry. Focused questions were addressed on (a) implant materials other than titanium (alloy)s, (b) transmucosal abutment materials and
(c) medications affecting bone metabolism were addressed.
Materials and Methods: Three systematic reviews formed the basis for discussion in
Group 3. Consensus statements and clinical recommendations were formulated by group
consensus based on the findings of the systematic reviews. Patient perspectives and
recommendations for future research were also conveyed. These were then presented
and accepted following further discussion and modifications as required by the plenary. Results: Zirconia is a valid alternative to titanium as material for implant and transmucosal components, allowing soft and hard tissue integration with clinical outcomes—
identified by implant survival, marginal bone loss and peri-implant probing depths—up
to 5-years comparable to titatnium. However, most of the evidence for zirconia implants is based on 1-piece implants limiting the indication range. Furthermore, based
on expert opinion, zirconia transmucosal components might be preferred in the esthetic zone. In patients receiving low-dose bisphosphonate therapy, the rate of early
implant failure is not increased, while the long-term effects remain poorly studied.
Although it has not been sufficiently addressed, similar outcomes can be expected
with low-dose denosumab. A drug holiday is not recommended when considering
implant placement in patients treated with low-dose ARD. However, the specific
therapeutic window, the cumulative dose and the administration time should be
considered. Access to peri-implant supportive care is mandatory to prevent periimplantitis-related medication-related osteonecrosis of the jaw (MRONJ) or implantrelated sequestra (IRS). In patients receiving low-dose anti-resorptive drugs (ARD)
therapy, the risk of complications related to implant placement is high, and implant
procedures in this specific population should be strictly treated in a comprehensive
multidisciplinary center. Finally, healthy dental implants should not be removed before low or high-dose ARD.
Conclusions: Zirconia implants can be an alternative to titanium implants in selected
indications. However, the current state of evidence remains limited, especially for 2-
piece implant designs. Administration of low-dose ARD did not show any negative
impact on early implant outcomes, but careful follow-up and supportive care is recommended in order to prevent peri-implant MRONJ and IRS. Implant placement in
high-dose patients must be strictly considered in a comprehensive multidisciplinary
center
Overcoming establishment thresholds for peat mosses in human-made bog pools
Globally, peatlands have been affected by drainage and peat extraction, with adverse effects on their functioning and services. To restore peat‐forming vegetation, drained bogs are being rewetted on a large scale. Although this practice results in higher groundwater levels, unfortunately it often creates deep lakes in parts where peat was extracted to greater depths than the surroundings. Revegetation of these deeper waters by peat mosses appears to be challenging due to strong abiotic feedbacks that keep these systems in an undesired bare state. In this study, we theoretically explore if a floating peat mat and an open human‐made bog lake can be considered two alternative stable states using a simple model, and experimentally test in the field whether stable states are present, and whether a state shift can be accomplished using floating biodegradable structures that mimic buoyant peat. We transplanted two peat moss species into these structures (pioneer sp. Sphagnum cuspidatum and later‐successional sp. S. palustre) with and without additional organic substrate. Our model suggests that these open human‐made bog lakes and floating peat mats can indeed be regarded as alternative stable states. Natural recovery by spontaneous peat moss growth, i.e., a state shift from open water to floating mats, is only possible when the water table is sufficiently shallow to avoid light limitation (<0.29 m at our site). Our experiment revealed that alternative stable states are present and that the floating structures facilitated the growth of pioneer S. cuspidatum and vascular plants. Organic substrate addition particularly facilitated vascular plant growth, which correlated to higher moss height. The structures remained too wet for the late‐successional species S. palustre. We conclude that open water and floating peat mats in human‐made bog lakes can be considered two alternative stable states, and that temporary floating establishment structures can induce a state shift from the open water state to peat‐forming vegetation state. These findings imply that for successful restoration, there is a clear water depth threshold to enable peat moss growth and there is no need for addition of large amounts of donor‐peat substrate. Correct species selection for restoration is crucial for success
Clinical and radiographic outcomes of zirconia dental implant : A systematic review and meta‐analysis
Objectives:
For the present review, the following focused question was addressed: In patients with root-analog dental implants, what is the effect of implants made of other materials than titanium (alloy) on implant survival, marginal bone loss (MBL), and technical and biological complications after at least 5 years.
Materials and Methods:
An electronic (Medline, Embase, Web of Science) search was performed to identify observational clinical studies published from January 2000 investigating a minimum of 20 commercially available zirconia implants with a mean follow-up of at least 60 months. Primary outcome was implant survival, secondary outcomes included peri-implant MBL, probing depths (PDs), and technical and biological complications. Meta-analyses were performed to evaluate implant survival, MBL, and PD.
Results:
From 5129 titles, 580 abstracts were selected, and 111 full-text articles were screened. Finally, 4 prospective and 2 retrospective observational clinical cohort studies were included for data extraction. Meta-analyses estimated after 5 years of loading mean values of 97.2% (95% CI 94.7–99.1) for survival (277 implants, 221 patients), 1.1 mm (95% CI: 0.9–1.3) for MBL (229 implants, 173 patients), and 3.0 mm (95% CI 2.5–3.4) for PDs (231 implants, 175 patients).
Conclusions:
After 5 years, commercially available zirconia implants showed reliable clinical performance based on survival rates, MBL, and PD values. However, more well-designed prospective clinical studies and randomized clinical trials investigating titanium and zirconia implants are needed to confirm the presently evaluated promising outcomes
Crestal bone response to loaded zirconia and titanium implants: a radiographic and histometric analysis in canines.
OBJECTIVES
To evaluate the crestal bone response to a two-piece zirconia implant compared with a control titanium implant using periapical radiographs (PAs) and histometry.
MATERIALS AND METHODS
Thirty zirconia and 30 titanium implants were placed in healed posterior mandibles of five canines. Full-ceramic single-tooth restorations were cemented after 6 weeks of healing. Three observers measured the distance between the implant shoulder and the crestal bone (DIB) at placement, loading, and harvesting after 4 or 16 weeks in function. The influence of implant material and loading time on DIB as well as the inter-observer agreement were analyzed. Additionally, histometric distance between implant shoulder and most coronal bone-to-implant contact (IS-cBIC) was compared with DIB.
RESULTS
Mean DIB values increased between 4 and 16 weeks of loading for both zirconia (from 1.66 to 2.25 mm; P < 0.0001) and titanium (from 1.81 to 1.95 mm; P = 0.06). Zirconia yielded mean IS-cBIC values of 2.18 mm and 2.48 mm (P < 0.001) and titanium 2.23 mm and 2.34 mm (P = 0.27) after 4 and 16 weeks, respectively. The raters reached an excellent intraclass correlation coefficient. PAs underestimated the bone loss on average by 0.39 mm.
CONCLUSIONS
Zirconia implants showed a greater increase of DIB during early healing and function than titanium.
CLINICAL RELEVANCE
Crestal peri-implant tissue dimensions may show more pronounced changes around two-piece zirconia implants during early healing. PAs may underestimate peri-implant bone loss