Should a metal post always be replaced before a new indirect -restoration?

Before realizing a new indirect restoration on an endodontically treated tooth, present restorations and possible posts need to be assessed. In the case of a metal post, the mismatch in flexural modulus between the dentine and the post might increase the risk of a vertical root fracture. Is it therefore prudent to replace such a metal post, before the fabrication of a new indirect restoration? Two scenarios might be considered to answer this question. First, would a glass fibre post result in a lower risk of failure? Two systematic reviews of the literature comparing glass fibre and metal posts for the short term were contradictory. Second, is the occurrence of a vertical root fracture associated with the presence of a post? Such association could not be established either. On the basis of the current literature, there does not appear to be evidence to support actively replacing a metal post

One of the last wild brown bears (Ursus arctos) in the Netherlands (Noordwijk)

Bioarchaeolog

Flora en fauna in en rond een Scheldegeul bij Kallo op het einde van het atlanticum (Beveren, prov. Oost-Vlaanderen)

Presented are the results of the analysis of botanical macroremains, pollen, mol, luscs, mammals, fish and a number of other remains from a deposit in the lower Scheldt basin north-west of Antwerp (Belgium). On the basis of these remains we can reconstruct the flora and fauna of this area during the late Atlantic. Tens of liters of a sandy basal layer of a gully-filling were sieved. A 1 piece of wood from this layer is radiocarbon dated 5750 ± 40 BP. Fifty meter from the gully a peat layer was sampled. The base has been dated to 6020 ± 70 BP and the top to 4630 ± 60 BP. This means that the gully was active during part of the formation of the peat. This peat is found in many places in the area and developed from halfway the Atlantic to halfway the Sub-Atlantic. Pollen analysis points to a deciduous forest during the Atlantic and Sub-Boreal. Alnus is the dominating species. The non-arboreal pollen amount to 10-30 % of all counted pollen, except water- and sporeplants. Evidently Alnus grows along the gully in wet forests, and in the somewhat higher places (riverbanks, riverdunes, borders of the valley) Quercus, Corylus, Tilia and Ulmus were present. In zones IV and V the percentage of Chenopodiaceae and Poaceae is high (marine influence?) and in zone VI sporeplants increase strongly. In the top part of layer 6 many plant and animal remains were present. Remarkable were large amounts of fruits and cones of AInus glutinosa. Nuphar lutea and Ranunculus (aquaticus-type) must have been present in the water. On higher places many shrubs and trees like Quercus robur and Tilia platyphyllos were growing. The deposit was also very rich in molluscs (86 species). We found species from a variety of freshwater habitats: from running to stagnant water, small pools, periodically dry waterbodies, etc. Mercuria confusa is an animal which is characteristic for the freshwater tidal area. Some species are very rare in Holocene deposits (and in the modern fauna) of this part of Europe. An example is a big pearl mussel Pseudanodonta auricularia. The same can be said for the remains of landmolluscs: they represent many habitats and interesting species. We found, e.g., Lauria cylindrica, Clausiliidae, Vertigo spp, Acanthinula aculeata, Helicigona lapicida. They lived in marshy places, moist to dry places with herbs and shrubs, and moist to dry deciduous forests. Other groups and species found are noted in chapter 9. All remains point to an area with a great variety of habitats in the valley of the River Scheldt. A gully with fresh water was influenced by the tides. Different types of waterbodies with stagnant water were present. Brooklets drained into the gully. Alder carr occured in the lower wet places. On the transition to higher grounds many shrubs were growing, and on the higher grounds themselves a deciduous forest was present

Records of Cepaea nemoralis (Linnaeus, 1758) (Gastropoda: Pulmonata) in the Bialowieza region in Poland

In April 2014, numerous specimens of Cepaea nemoralis were found in Budy, a village in the Białowieża region of eastern Poland. This record sets the total number of mollusc species known to this region to 115. The other locality, in the village Brok about 140 km west of Białowieża, indicates that the species is spreading to the northeast

The past and present occurrence of Elatine and implications for palaeoenvironmental reconstructions

The past and present occurrence of Elatine hydropiper L. (eight-stamened waterwort), E. hexandra (Lapierre) DC. (six-stamened waterwort) and E. triandra Schkuhr (three-stamened waterwort) in the Netherlands is discussed. It has proved possible to distinguish the slightly curved seeds of E. hexandra and E. triandra in subfossil material on morphological grounds. E. hexandra is the most common species at present, but subfossil finds are confined to Late-glacial and Pre-boreal sediments of one lake in the Pleistocene area of the Netherlands. Living plants of E. triandra have only been found in the Netherlands in 1838-1839, but there are 17 records from five archaeological sites, all located in the western Dutch estuarine area. Several of these sites also yielded E. hydropiper, archaeobotanically the most common species. The occurrence of E. triandra and E. hydropiper in the Netherlands seems to have been favoured by high summer temperatures. The ecological amplitude of this combination of species gives firm clues for the reconstruction of the environment, which must have been a freshwater tidal area. Since this type of environment is strongly threatened on a worldwide scale, the presence of these species in the past may also provide interesting information for present nature development projects in the Dutch estuarine area. © 2007 Springer Verlag

Plangebied Smitsweg-smitshoek, gemeente Dordrecht : archeologisch vooronderzoek: een bureau- en inventariserend veldonderzoek

Lit.opg