Quantification of plasma carnitine and acylcarnitines by high-performance liquid chromatography-tandem mass spectrometry using online solid-phase extraction

Carnitine is an amino acid derivative that plays a key role in energy metabolism. Endogenous carnitine is found in its free form or esterified with acyl groups of several chain lengths. Quantification of carnitine and acylcarnitines is of particular interest for screening for research and metabolic disorders. We developed a method with online solid-phase extraction coupled to high-performance liquid chromatography and tandem mass spectrometry to quantify carnitine and three acylcarnitines with different polarity (acetylcarnitine, octanoylcarnitine, and palmitoylcarnitine). Plasma samples were deproteinized with methanol, loaded on a cation exchange trapping column and separated on a reversed-phase C8 column using heptafluorobutyric acid as an ion-pairing reagent. Considering the endogenous nature of the analytes, we quantified with the standard addition method and with external deuterated standards. Solid-phase extraction and separation were achieved within 8 min. Recoveries of carnitine and acylcarnitines were between 98 and 105 %. Both quantification methods were equally accurate (all values within 84 to 116 % of target concentrations) and precise (day-to-day variation of less than 18 %) for all carnitine species and concentrations analyzed. The method was used successfully for determination of carnitine and acylcarnitines in different human samples. In conclusion, we present a method for simultaneous quantification of carnitine and acylcarnitines with a rapid sample work-up. This approach requires small sample volumes and a short analysis time, and it can be applied for the determination of other acylcarnitines than the acylcarnitines tested. The method is useful for applications in research and clinical routine.

Class II treatment by extraction of maxillary first molars or Herbst appliance: dentoskeletal and soft tissue effects in comparison

AIM To compare dentoskeletal and soft tissue treatment effects of two alternative Class II division 1 treatment modalities (maxillary first permanent molar extraction versus Herbst appliance). METHODS One-hundred-fifty-four Class II division 1 patients that had either been treated with extractions of the upper first molars and a lightwire multibracket (MB) appliance (n = 79; 38 girls, 41 boys) or non-extraction by means of a Herbst-MB appliance (n = 75; 35 girls, 40 boys). The groups were matched on age and sex. The average age at the start of treatment was 12.7 years for the extraction and for 13.0 years for the Herbst group. Pretreatment (T1) and posttreatment (T2) lateral cephalograms were retrospectively analyzed using a standard cephalometric analysis and the sagittal occlusal analysis according to Pancherz. RESULTS The SNA decrease was 1.10° (p = 0.001) more pronounced in the extraction group, the SNB angle increased 1.49° more in the Herbst group (p = 0.000). In the extraction group, a decrease in SNB angle (0.49°) was observed. The soft tissue profile convexity (N-Sn-Pog) decreased in both groups, which was 0.78° more (n. s.) pronounced in the Herbst group. The nasolabial angle increased significantly more (+ 2.33°, p = 0.025) in the extraction group. The mechanism of overjet correction in the extraction group was predominantly dental (65% dental and 35% skeletal changes), while in the Herbst group it was predominantly skeletal (58% skeletal and 42% dental changes) in origin. CONCLUSION Both treatment methods were successful and led to a correction of the Class II division 1 malocclusion. Whereas for upper first molar extraction treatment more dental and maxillary effects can be expected, in case of Herbst treatment skeletal and mandibular effects prevail.

Clinical results with two different methods of root-end preparation and filling in apical surgery: mineral trioxide aggregate and adhesive resin composite

INTRODUCTION: The aim of apical surgery is to hermetically seal the root canal system after root-end resection, thereby enabling periradicular healing. The objective of this nonrandomized prospective clinical study was to report results of 2 different root-end preparation and filling methods, ie, mineral trioxide aggregate (MTA) and an adhesive resin composite (Retroplast). METHODS: The study included 353 consecutive cases with endodontic lesions limited to the periapical area. Root-end cavities were prepared with sonic microtips and filled with MTA (n = 178), or alternatively, a shallow concavity was prepared in the cut root face, with subsequent placement of an adhesive resin composite (Retroplast) (n = 175). Patients were recalled after 1 year. Cases were defined as healed when no clinical signs or symptoms were present and radiographs demonstrated complete or incomplete (scar tissue) healing of previous radiolucencies. RESULTS: The overall rate of healed cases was 85.5%. MTA-treated teeth demonstrated a significantly (P = .003) higher rate of healed cases (91.3%) compared with Retroplast-treated teeth (79.5%). Within the MTA group, 89.5%-100% of cases were classified as healed, depending on the type of treated tooth. In contrast, more variable rates ranging from 66.7%-100% were found in the Retroplast group. In particular, mandibular premolars and molars demonstrated considerably lower rates of healed cases when treated with Retroplast. CONCLUSIONS: MTA can be recommended for root-end filling in apical surgery, irrespective of the type of treated tooth. Retroplast should be used with caution for root-end sealing in apical surgery of mandibular premolars and molars.

The performance of conventional and fluorescence-based methods for occlusal caries detection: an in vivo study with histologic validation

The authors conducted an in vivo study to determine clinical cutoffs for a laser fluorescence (LF) device, an LF pen and a fluorescence camera (FC), as well as to evaluate the clinical performance of these methods and conventional methods in detecting occlusal caries in permanent teeth by using the histologic gold standard for total validation of the sample.

Generation and analysis of a mouse intestinal metatranscriptome through Illumina based RNA-sequencing

With the advent of high through-put sequencing (HTS), the emerging science of metagenomics is transforming our understanding of the relationships of microbial communities with their environments. While metagenomics aims to catalogue the genes present in a sample through assessing which genes are actively expressed, metatranscriptomics can provide a mechanistic understanding of community inter-relationships. To achieve these goals, several challenges need to be addressed from sample preparation to sequence processing, statistical analysis and functional annotation. Here we use an inbred non-obese diabetic (NOD) mouse model in which germ-free animals were colonized with a defined mixture of eight commensal bacteria, to explore methods of RNA extraction and to develop a pipeline for the generation and analysis of metatranscriptomic data. Applying the Illumina HTS platform, we sequenced 12 NOD cecal samples prepared using multiple RNA-extraction protocols. The absence of a complete set of reference genomes necessitated a peptide-based search strategy. Up to 16% of sequence reads could be matched to a known bacterial gene. Phylogenetic analysis of the mapped ORFs revealed a distribution consistent with ribosomal RNA, the majority from Bacteroides or Clostridium species. To place these HTS data within a systems context, we mapped the relative abundance of corresponding Escherichia coli homologs onto metabolic and protein-protein interaction networks. These maps identified bacterial processes with components that were well-represented in the datasets. In summary this study highlights the potential of exploiting the economy of HTS platforms for metatranscriptomics.

Effects of prolonged endotoxemia on liver, skeletal muscle and kidney mitochondrial function

INTRODUCTION: Sepsis may impair mitochondrial utilization of oxygen. Since hepatic dysfunction is a hallmark of sepsis, we hypothesized that the liver is more susceptible to mitochondrial dysfunction than the peripheral tissues, such as the skeletal muscle. We studied the effect of prolonged endotoxin infusion on liver, muscle and kidney mitochondrial respiration and on hepatosplanchnic oxygen transport and microcirculation in pigs. METHODS: 20 anesthetized pigs were randomized to receive endotoxin or saline infusion for 24 hours. Muscle, liver and kidney mitochondrial respiration was assessed. Cardiac output (thermodilution), carotid, superior mesenteric and kidney arterial, portal venous (ultrasound Doppler) and microcirculatory blood flow (laser Doppler) were measured, and systemic and regional oxygen transport and lactate exchange were calculated. RESULTS: Endotoxin infusion induced hyperdynamic shock and impaired the glutamate- and succinate-dependent mitochondrial respiratory control ratio (RCR) in the liver (glutamate: endotoxemia: median [range] 2.8 [2.3-3.8] vs. controls: 5.3 [3.8-7.0]; p<0.001; succinate: endotoxemia: 2.9 [1.9-4.3] vs. controls: 3.9 [2.6-6.3] p=0.003). While the ADP:O ratio was reduced with both substrates, maximal ATP production was impaired only in the succinate-dependent respiration. Hepatic oxygen consumption and extraction, and liver surface laser Doppler blood flow remained unchanged. Glutamate-dependent respiration in the muscle and kidney was unaffected. CONCLUSIONS: Endotoxemia reduces the efficiency of hepatic but neither skeletal muscle nor kidney mitochondrial respiration, independent of regional and microcirculatory blood flow changes.

Methods and representativeness of a European survey in children and adolescents: the KIDSCREEN study

BACKGROUND: The objective of the present study was to compare three different sampling and questionnaire administration methods used in the international KIDSCREEN study in terms of participation, response rates, and external validity. METHODS: Children and adolescents aged 8-18 years were surveyed in 13 European countries using either telephone sampling and mail administration, random sampling of school listings followed by classroom or mail administration, or multistage random sampling of communities and households with self-administration of the survey materials at home. Cooperation, completion, and response rates were compared across countries and survey methods. Data on non-respondents was collected in 8 countries. The population fraction (PF, respondents in each sex-age, or educational level category, divided by the population in the same category from Eurostat census data) and population fraction ratio (PFR, ratio of PF) and their corresponding 95% confidence intervals were used to analyze differences by country between the KIDSCREEN samples and a reference Eurostat population. RESULTS: Response rates by country ranged from 18.9% to 91.2%. Response rates were highest in the school-based surveys (69.0%-91.2%). Sample proportions by age and gender were similar to the reference Eurostat population in most countries, although boys and adolescents were slightly underrepresented (PFR <1). Parents in lower educational categories were less likely to participate (PFR <1 in 5 countries). Parents in higher educational categories were overrepresented when the school and household sampling strategies were used (PFR = 1.78-2.97). CONCLUSION: School-based sampling achieved the highest overall response rates but also produced slightly more biased samples than the other methods. The results suggest that the samples were sufficiently representative to provide reference population values for the KIDSCREEN instrument.

The effect of periodontal therapy on the survival rate and incidence of complications of multirooted teeth with furcation involvement after an observation period of at least 5 years: a systematic review

OBJECTIVE: To systematically review the survival rate and incidence of complications of furcation-involved multirooted teeth following periodontal therapy after at least 5 years. MATERIAL AND METHODS: Electronic and manual searches were performed up to and including January 2008. Publication selection, data extraction and validity assessment were performed independently by three reviewers. RESULTS: Twenty-two publications met the inclusion criteria. Because of the heterogeneity of the data, a meta-analysis could not be performed. The survival rate of molars treated non-surgically was >90% after 5-9 years. The corresponding values for the different surgical procedures were: Surgical therapy: 43.1% to 96%, observation period: 5-53 years. Tunnelling procedures: 42.9% to 92.9%, observation period: 5-8 years. Surgical resective procedures including amputation(s) and hemisections: 62% to 100%, observation period: 5-13 years. Guided tissue regeneration (GTR): 83.3% to 100%, observation period: 5-12 years. The most frequent complications included caries in the furcation area after tunnelling procedures and root fractures after root-resective procedures. CONCLUSIONS: Good long-term survival rates (up to 100%) of multirooted teeth with furcation involvement were obtained following various therapeutic approaches. Initial furcation involvement (Degree I) could be successfully managed by non-surgical mechanical debridement. Vertical root fractures and endodontic failures were the most frequent complications observed following resective procedures.

A computer-aided diagnostic system to characterize CT focal liver lesions: design and optimization of a neural network classifier

In this paper, a computer-aided diagnostic (CAD) system for the classification of hepatic lesions from computed tomography (CT) images is presented. Regions of interest (ROIs) taken from nonenhanced CT images of normal liver, hepatic cysts, hemangiomas, and hepatocellular carcinomas have been used as input to the system. The proposed system consists of two modules: the feature extraction and the classification modules. The feature extraction module calculates the average gray level and 48 texture characteristics, which are derived from the spatial gray-level co-occurrence matrices, obtained from the ROIs. The classifier module consists of three sequentially placed feed-forward neural networks (NNs). The first NN classifies into normal or pathological liver regions. The pathological liver regions are characterized by the second NN as cyst or "other disease." The third NN classifies "other disease" into hemangioma or hepatocellular carcinoma. Three feature selection techniques have been applied to each individual NN: the sequential forward selection, the sequential floating forward selection, and a genetic algorithm for feature selection. The comparative study of the above dimensionality reduction methods shows that genetic algorithms result in lower dimension feature vectors and improved classification performance.

Geochemical synthesis for the Effingen Member in boreholes at Oftringen, Gösgen and Küttigen

The Effingen Member is a low-permeability rock unit of Oxfordian age (ca. 160 Ma) that occurs across northern Switzerland. It comprises sandy calcareous marls and (argillaceous) limestones. This report describes the hydrogeochemistry, mineralogy and supporting physical properties of the Effingen Member in three boreholes in the Jura-Südfuss area: Oftringen, Gösgen and Küttigen, where it is 220–240 m thick. The top of the Effingen Member is at 420, 66 and 32 m depths at the three sites. Core materials are available from Oftringen and Gösgen, whereas information from Küttigen is limited to cuttings, in-situ hydrogeological testing and geophysical logging. Hydrogeological boundaries of the Effingen Member vary between locations. Ground-water flows were identified during drilling at the top (Geissberg Member), but not at the base, of the Effingen Member at Oftringen, at the base (Hauptrogenstein Formation) of the Effingen Member at Gösgen, and in a limestone layer (Gerstenhübel unit) within the Effingen Member at Küttigen. The marls and limestones of the Effingen Member have carbonate contents of 46–91 wt.-% and clay-mineral contents of 5–37 wt.-%. Pyrite contents are up to 1.6 wt.-%, but no sulphate minerals were detected by routine analyses. Clay minerals are predominantly mixed-layer illite-smectite, illite and kaolinite, with sporadic traces of chlorite and smectite. Veins filled with calcite ± celestite occur through the Effingen Member at Oftringen but not at Gösgen or Küttigen. They formed at 50–70 ºC from externally derived fluids, probably of Miocene age. Water contents are 0.7–4.2 wt.-%, corresponding to a water-loss porosity range of 1.9–10.8 vol.-%. Specific surface areas, measured by the BET method, are 2–30 m2/g, correlating with clay-mineral contents. Water activity has been measured and yielded surprisingly low values down to 0.8. These cannot be explained by pore-water salinity alone and include other effects, such as changes in the fabric due to stress release or partial saturation. Observed variations in measurements are not fully understood. Cation exchange capacity (CEC) and exchangeable cation populations have been studied by the Ni-en method. CEC, derived from the consumption of the index cation Ni, is 9–99 meq/kgrock at a solid:liquid ratio of 1, correlating with the clay-mineral content. Cation concentrations in Ni-en extract solutions are in the order Na+≥Ca2+>Mg2+>K+>Sr2+. However, the analytical results from the Ni-en extractions have additional contributions from cations originating from pore water and from mineral dissolution reactions that occurred during extraction, and it was not possible to reliably quantify these contributions. Therefore, in-situ cation populations and selectivity coefficients could not be derived. A suite of methods have been used for characterising the chemical compositions of pore waters in the Effingen Member. Advective displacement was used on one sample from each Oftringen and Gösgen and is the only method that produces results that approach complete hydrochemical compositions. Aqueous extraction was used on core samples from these two boreholes and gives data only for Cl- and, in some cases, Br-. Out-diffusion was used on core samples from Oftringen and similarly gives data for Cl- and Br- only. For both aqueous extraction and out-diffusion, reaction of the experimental water with rock affected concentrations of cations, SO42 and alkalinity in experimental solutions. Another method, centrifugation, failed to extract pore water. Stable isotope ratios (δ18O and δ2H) of pore waters in core samples from Oftringen were analysed by the diffusive exchange method and helium contents of pore water in Oftringen samples were extracted for mass spectrometric analysis by quantitative outgassing of preserved core samples. Several lines of evidence indicate that drillcore samples might not have been fully saturated when opened and subsampled in the laboratory. These include comparisons of water-loss porosities with physical porosities, water-activity measurements, and high contents of dissolved gas as inferred from ground-water samples. There is no clear proof of partial saturation and it is unclear whether this might represent in-situ conditions or is due to exsolution of gas due to the pressure release since drilling. Partial saturation would have no impact on the recalculation of pore-water compositions from aqueous extraction experiments using water-loss porosity data. The largest uncertainty in the pore-water Cl- concentrations recalculated from aqueous extraction and out-diffusion experiments is the magnitude of the anion-accessible fraction of water-loss porosity. General experience of clay-mineral rich formations suggests that the anion-accessible porosity fraction is very often about 0.5 and generally in a range of 0.3 to 0.6 and tends to be inversely correlated with clay-mineral contents. Comparisons of the Cl- concentration in pore water obtained by advective displacement with that recalculated from aqueous extraction of an adjacent core sample suggests a fraction of 0.27 for an Oftringen sample, whereas the same procedure for a Gösgen sample suggests a value of 0.64. The former value for anion-accessible porosity fraction is presumed to be unrepresentative given the local mineralogical heterogeneity at that depth. Through-diffusion experiments with HTO and 36Cl- suggest that the anion-accessible porosity fraction in the Effingen Member at Oftringen and Gösgen is around 0.5. This value is proposed as a typical average for rocks of the Effingen Member, bearing in mind that it varies on a local scale in response to the heterogeneity of lithology and pore-space architecture. The substantial uncertainties associated with the approaches to estimating anion-accessible porosity propagate into the calculated values of in-situ pore-water Cl- concentrations. On the basis of aqueous extraction experiments, and using an anion-accessible porosity fraction of 0.5, Cl- concentrations in the Effingen Member at Oftringen reach a maximum of about 14 g/L in the centre. Cl- decreases upwards and downwards from that, forming a curved depth profile. Cl- contents in the Effingen Member at Gösgen increase with depth from about 3.5 g/L to about 14 g/L at the base of the cored profile (which corresponds to the centre of the formation). Out-diffusion experiments were carried out on four samples from Oftringen, distributed through the Effingen Member. Recalculated Cl- concentrations are similar to those from aqueous extraction for 3 out of the 4 samples, and somewhat lower for one sample. Concentrations of other components, i.e. Na+, K+, Ca2+, Mg2+, Sr2+, SO42- and HCO3- cannot be obtained from the aqueous extraction and out-diffusion experimental data because of mineral dissolution and cation exchange reactions during the experiments. Pore-water pH also is not constrained by those extraction experiments. The only experimental approach to obtain complete pore-water compositions for samples from Oftringen and Gösgen is advective displacement of pore water. The sample from Oftringen used for this experiment is from 445 m depth in the upper part of the Effingen Member and gave eluate with 16.5 g/L Cl- whereas aqueous extraction from a nearby sample indicated about 9 g/L Cl-. The sample from Gösgen used for advective displacement is from 123 m depth in the centre of the Effingen Member sequence and gave eluate with about 9 g/L Cl- whereas aqueous extraction gave 11.5 g/L Cl-. In both cases the pore waters have Na-(Ca)-Cl compositions and SO42- concentrations of about 1.1 g/L. The Gösgen sample has a Br/Cl ratio similar to that of sea water, whereas this ratio is lower for the Oftringen sample. Taking account of uncertainties in the applied experimental approaches, it is reasonable to place an upper limit of ca. 20 g/L on Cl- concentration for pore water in the Effingen Member in this area. There are major discrepancies between pore-water SO42- concentrations inferred from aqueous extraction or out-diffusion experiments and those obtained from advective displacement in both the Oftringen and Gösgen cases. A general conclusion is that all or at least part of the discrepancies are attributable to perturbation of the sulphur system and enhancement of SO42- by sulphate mineral dissolution and possibly minor pyrite oxidation during aqueous extraction and out-diffusion. Therefore, data for SO42- calculated from those pore-water sampling methods are considered not to be representative of in-situ conditions. A reference pore-water composition was defined for the Effingen Member in the Jura Südfuss area. It represents the probable upper limits of Cl- contents and corresponding anion and cation concentrations that are reasonably constrained by experimental data. Except for Cl- and possibly Na+ concentrations, this composition is poorly constrained especially with respect to SO42- and Ca2+ concentrations, and pH and alkalinity. Stable isotope compositions, δ18O and δ2H, of pore waters in the Effingen Member at Oftringen plot to the right of the meteoric water line, suggesting that 18O has been enriched by water-rock exchange, which indicates that the pore waters have a long residence time. A long residence time of pore water is supported by the level of dissolved 4He that has accumulated in pore water of the Effingen Member at Oftringen. This is comparable with, or slightly higher than, the amounts of 4He in the Opalinus Clay at Benken. Ground waters were sampled from flowing zones intersected by boreholes at the three locations. The general interpretation is that pore waters and ground-water solutes may have similar origins in Mesozoic and Cenozoic brackish-marine formations waters, but ground-water solutes have been diluted rather more than pore waters by ingress of Tertiary and Quaternary meteoric waters. The available hydrochemical data for pore waters from the Effingen Member at these three locations in the Jura-Südfuss area suggest that the geochemical system evolved slowly over geological periods of time, in which diffusion was an important mechanism of solute transport. The irregularity of Cl- and δ18O profiles and spatial variability of advective ground-water flows in the Malm-Dogger system suggests that palaeohydrogeological and hydrochemical responses to changing tectonic and surface environmental conditions were complex.

Different Contribution of Splanchnic Organs to Hyperlactatemia in Fecal Peritonitis and Cardiac Tamponade

Background. Changes in hepatosplanchnic lactate exchange are likely to contribute to hyperlactatemia in sepsis. We hypothesized that septic and cardiogenic shock have different effects on hepatosplanchnic lactate exchange and its contribution to hyperlactatemia. Materials and Methods. 24 anesthetized pigs were randomized to fecal peritonitis (P), cardiac tamponade (CT), and to controls ( per group). Oxygen transport and lactate exchange were calculated during 24 hours. Results. While hepatic lactate influx increased in P and in CT, hepatic lactate uptake remained unchanged in P and decreased in CT. Hepatic lactate efflux contributed 20% (P) and 33% (CT), respectively, to whole body venous efflux. Despite maintained hepatic arterial blood flow, hepatic oxygen extraction did not increase in CT. Conclusions. Whole body venous lactate efflux is of similar magnitude in hyperdynamic sepsis and in cardiogenic shock. Although jejunal mucosal pCO2 gradients are increased, enhanced lactate production from other tissues is more relevant to the increased arterial lactate. Nevertheless, the liver fails to increase hepatic lactate extraction in response to rising hepatic lactate influx, despite maintained hepatic oxygen consumption. In cardiac tamponade, regional, extrasplanchnic lactate production is accompanied by hepatic failure to increase oxygen extraction and net hepatic lactate output, despite maintained hepatic arterial perfusion.

In vitro differentiation of mouse granulocytes. Programmed Cell Death: Methods and Protocols

Granulocytes are central players of the immune system and, once activated, a tightly controlled balance between effector functions and cell removal by apoptosis guarantees maximal host benefit with least possible collateral damage to healthy tissue. Granulocytes are end-differentiated cells that cannot be maintained in culture for prolonged times. Isolating primary granulocytes is inefficient and challenging when working with mice, and especially so for the lowly abundant eosinophil and basophils subtypes. Here we describe an in vitro protocol to massively expand mouse derived myeloid progenitors and to differentiate them ‘on demand’ and in large numbers into mature neutrophils or basophils.

Long-term evaluation of Class II subdivision treatment with unilateral maxillary first molar extraction

OBJECTIVE To evaluate the long-term effects of asymmetrical maxillary first molar (M1) extraction in Class II subdivision treatment. MATERIALS AND METHODS Records of 20 Class II subdivision whites (7 boys, 13 girls; mean age, 13.0 years; SD, 1.7 years) consecutively treated with the Begg technique and M1 extraction, and 15 untreated asymmetrical Class II adolescents (4 boys, 11 girls; mean age, 12.2 years; SD, 1.3 years) were examined in this study. Cephalometric analysis and PAR assessment were carried out before treatment (T1), after treatment (T2), and on average 2.5 years posttreatment (T3) for the treatment group, and at similar time points and average follow-up of 1.8 years for the controls. RESULTS The adjusted analysis indicated that the maxillary incisors were 2.3 mm more retracted in relation to A-Pog between T1 and T3 (β  =  2.31; 95% CI; 0.76, 3.87), whereas the mandibular incisors were 1.3 mm more protracted (β  =  1.34; 95% CI; 0.09, 2.59), and 5.9° more proclined to the mandibular plane (β  =  5.92; 95% CI; 1.43, 10.41) compared with controls. The lower lip appeared 1.4 mm more protrusive relative to the subnasale-soft tissue-Pog line throughout the observation period in the treated adolescents (β  =  1.43; 95% CI; 0.18, 2.67). There was a significant PAR score reduction over the entire follow-up period in the molar extraction group (β  =  -6.73; 95% CI; -10.7, -2.7). At T2, 65% of the subjects had maxillary midlines perfectly aligned with the face. CONCLUSIONS Unilateral M1 extraction in asymmetrical Class II cases may lead to favorable occlusal outcomes in the long term without harming the midline esthetics and soft tissue profile.

A systematic review on the innervation of peri-implant tissues with special emphasis on the influence of implant placement and loading protocols

OBJECTIVES To systematically review the available literature on the influence of dental implant placement and loading protocols on peri-implant innervation. MATERIAL AND METHODS The database MEDLINE, Cochrane, EMBASE, Web of Science, LILACS, OpenGrey and hand searching were used to identify the studies published up to July 2013, with a populations, exposures and outcomes (PEO) search strategy using MeSH keywords, focusing on the question: Is there, and if so, what is the effect of time between tooth extraction and implant placement or implant loading on neural fibre content in the peri-implant hard and soft tissues? RESULTS Of 683 titles retrieved based on the standardized search strategy, only 10 articles fulfilled the inclusion criteria, five evaluating the innervation of peri-implant epithelium, five elucidating the sensory function in peri-implant bone. Three included studies were considered having a methodology of medium quality and the rest were at low quality. All those papers reported a sensory innervation around osseointegrated implants, either in the bone-implant interface or peri-implant epithelium, which expressed a particular innervation pattern. Compared to unloaded implants or extraction sites without implantation, a significant higher density of nerve fibres around loaded dental implants was confirmed. CONCLUSIONS To date, the published literature describes peri-implant innervation with a distinct pattern in hard and soft tissues. Implant loading seems to increase the density of nerve fibres in peri-implant tissues, with insufficient evidence to distinguish between the innervation patterns following immediate and delayed implant placement and loading protocols. Variability in study design and loading protocols across the literature and a high risk of bias in the studies included may contribute to this inconsistency, revealing the need for more uniformity in reporting, randomized controlled trials, longer observation periods and standardization of protocols.