Partial lateralization of the nasopalatine nerve at the incisive foramen for ridge augmentation in the anterior maxilla prior to placement of dental implants: a retrospective case series evaluating self-reported data and neurosensory testing

The objective of this study was to assess implant therapy after a staged guided bone regeneration procedure in the anterior maxilla by lateralization of the nasopalatine nerve and vessel bundle. Neurosensory function following augmentative procedures and implant placement, assessed using a standardized questionnaire and clinical examination, were the primary outcome variables measured. This retrospective study included patients with a bone defect in the anterior maxilla in need of horizontal and/or vertical ridge augmentation prior to dental implant placement. The surgical sites were allowed to heal for at least 6 months before placement of dental implants. All patients received fixed implant-supported restorations and entered into a tightly scheduled maintenance program. In addition to the maintenance program, patients were recalled for a clinical examination and to fill out a questionnaire to assess any changes in the neurosensory function of the nasopalatine nerve at least 6 months after function. Twenty patients were included in the study from February 2001 to December 2010. They received a total of 51 implants after augmentation of the alveolar crest and lateralization of the nasopalatine nerve. The follow-up examination for questionnaire and neurosensory assessment was scheduled after a mean period of 4.18 years of function. None of the patients examined reported any pain, they did not have less or an altered sensation, and they did not experience a "foreign body" feeling in the area of surgery. Overall, 6 patients out of 20 (30%) showed palatal sensibility alterations of the soft tissues in the region of the maxillary canines and incisors resulting in a risk for a neurosensory change of 0.45 mucosal teeth regions per patient after ridge augmentation with lateralization of the nasopalatine nerve. Regeneration of bone defects in the anterior maxilla by horizontal and/or vertical ridge augmentation and lateralization of the nasopalatine nerve prior to dental implant placement is a predictable surgical technique. Whether or not there were clinically measurable impairments of neurosensory function, the patients did not report them or were not bothered by them.

Stand scale variability of topsoil organic matter composition in a high-elevation Norway spruce forest ecosystem

Our knowledge about the effect of single-tree influence areas on the physicochemical properties of the underlying mineral soil in forest ecosystems is still limited. This restricts our ability to adequately estimate future changes in soil functioning due to forest management practices. We studied the stand scale spatial variation of different soil organic matter species investigated by 13C NMR spectroscopy, lignin phenol and neutral sugar analysis under an unmanaged mountainous high-elevation Norway spruce (Picea abies L.) forest in central Europe. Multivariate geostatistical approaches were applied to relate the spatial patterns of the different soil organic matter species to topographic parameters, bulk density, oxalate- and dithionite-extractable iron, pH, and the impact of tree distribution. Soil samples were taken from the mineral top soil. Generally, the stand scale distribution patterns of different soil organic matter compounds could be divided into two groups: Those compounds, which were significantly spatially correlated with topography/altitude and those with small scale spatial pattern (range ≤ 10 m) that was closely related to tree distribution. The concentration of plant-derived soil organic matter components, such as lignin, at a given sampling point was significantly spatially related to the distance of the nearest tree (p ≤ 0.05). In contrast, the spatial distribution of mainly microbial-derived compounds (e.g. galactose and mannose) could be attributed to the dominating impact of small-scale topography and the contribution of poorly crystalline iron oxides that were significantly larger in the central depression of the study site compared to crest and slope positions. Our results demonstrate that topographic parameters dominate the distribution of overall topsoil organic carbon (OC) stocks at temperate high-elevation forest ecosystems, particularly in sloped terrain. However, trees superimpose topography-controlled OC biogeochemistry beneath their crown by releasing litter and changing soil conditions in comparison to open areas. This may lead to distinct zones with different mechanisms of soil organic matter degradation and also stabilization in forest stands.

The Ets domain transcription factor Erm distinguishes rat satellite glia from Schwann cells and is regulated in satellite cells by neuregulin signaling

Distinct glial cell types of the vertebrate peripheral nervous system (PNS) are derived from the neural crest. Here we show that the expression of the Ets domain transcription factor Erm distinguishes satellite glia from Schwann cells beginning early in rat PNS development. In developing dorsal root ganglia (DRG), Erm is present both in presumptive satellite glia and in neurons. In contrast, Erm is not detectable at any developmental stage in Schwann cells in peripheral nerves. In addition, Erm is downregulated in DRG-derived glia adopting Schwann cell traits in culture. Thus, Erm is the first described transcription factor expressed in satellite glia but not in Schwann cells. In culture, the Neuregulin1 (NRG1) isoform GGF2 maintains Erm expression in presumptive satellite cells and reinduces Erm expression in DRG-derived glia but not in Schwann cells from sciatic nerve. These data demonstrate that there are intrinsic differences between these glial subtypes in their response to NRG1 signaling. In neural crest cultures, Erm-positive progenitor cells give rise to two distinct glial subtypes: Erm-positive, Oct-6-negative satellite glia in response to GGF2, and Erm-negative, Oct-6-positive Schwann cells in the presence of serum and the adenylate cyclase activator forskolin. Thus, Erm-positive neural crest-derived progenitor cells and presumptive satellite glia are able to acquire Schwann cell features. Given the in vivo expression of Erm in peripheral ganglia, we suggest that ganglionic Erm-positive cells may be precursors of Schwann cells.