[Perinatal Networks: Ensuring Regional Care of Pregnant Woman and Newborns]. / Perinatologische Kompetenznetzwerke: Die Versorgung von Schwangeren und Neugeborenen in einer Region.

Health care of pregnant women and their newborns is facing major challenges due to the decline in birth rate and shortage of specialists. In the current discussion about future concepts, the centralization associated with minimum quantities and the necessary safeguarding of care in the area are often construed as conflicting goals. Instead, concepts are needed to guarantee that pregnant women and their children will continue to receive care close to home. The example of the saxony center for feto/neonatal health is used to show how partners in a region can jointly ensure care during pregnancy, birth and the neonatal period on a supra-local and cross-hospital basis. The close cooperation of maximum care providers with regional partners enables comprehensive health care. At the same time, this cooperation enables hospitals to remain attractive employers in structurally weak regions and to provide comprehensive care for young families in need of medical services related to pregnancy and birth through good family and social integration close to home and work. The overriding goals of the saxony center for feto/neonatal health are optimal, guideline-based, interdisciplinary and intersectoral care of pregnant women and premature or sick newborns in the region.

Gentle as a mother's touch: C-tactile touch promotes autonomic regulation in preterm infants.

Preterm infants are challenged to adapt to an extrauterine milieu, while their interoceptive system and autonomic regulation capacity is still immature. Caressing parental touch is known to foster parasympathetic regulation in infants by stimulating C-tactile (CT) afferents and in preterm infants, slow stroking stimulation also leads to a heart rate decrease. The particular impact of maternal stroking has not yet been investigated and factors influencing the maturation of the CT system in preterm infants remain unclear. We therefore analysed 53 standardized events in which preterm infants (24 to 36 weeks gestational age at birth) were stroked by their mothers. Video analysis revealed that mothers use CT optimal velocities to stroke their preterm child. Analysis of pulse oximetric data showed no effect of stroking on infantile blood oxygenation, but a significant decrease of the heart rate. Compared to term-born children, this decrease was delayed by about two minutes. Furthermore, our data suggested that more immature preterm infants benefited less from stroking than more mature ones. We conclude that maternal stroking touch targets CT afferents in preterm infants and that the preterm CT system is not yet mature.

Comparison of mental health outcomes in seropositive and seronegative adolescents during the COVID19 pandemic.

Post-COVID19 complications such as pediatric inflammatory multisystem syndrome (PIMS) and Long-COVID19 move increasingly into focus, potentially causing more harm in young adolescents than the acute infection. To better understand the symptoms of long-term mental health outcomes in adolescents and distinguish infection-associated symptoms from pandemic-associated symptoms, we conducted a 12 question Long-COVID19 survey. Using this survey, we compared the responses on neurocognitive, general pain and mood symptoms from seropositive and seronegative adolescents in a cross-sectional study design. Since May 2020, students grade 8-12 in fourteen secondary schools in Eastern Saxony were enrolled in the SchoolCovid19 study. Serostatus was assessed regularly in all participants. In March/April 2021, 1560 students with a median age of 15 years participated at the regular study visit after re-opening of the schools in mid-March and responded to our Long-COVID19 survey as part of this visit. 1365 (88%) students were seronegative, 188 (12%) were seropositive. Each symptom asked in the Long-COVID19 survey was present in at least 35% of the students within the last seven days before the survey. With the exception of seropositive students being less sad, there was no significant difference comparing the reported symptoms between seropositive students and seronegative students. The lack of differences comparing the reported symptoms between seropositive and seronegative students suggests that Long-COVID19 might be less common than previously thought and emphasizes on the impact of pandemic-associated symptoms regarding the well-being and mental health of young adolescents.Clinical Trial Registration: SchoolCoviDD19: Prospektive Erfassung der SARS-CoV-2 Seropositivität bei Schulkindern nach Ende der unterrichtsfreien Zeit aufgrund der Corona-Schutz-Verordnung (COVID-19), DRKS00022455, https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00022455.

Prenatal Methamphetamine Exposure: Effects on Child Development­A Systematic Review.

BACKGROUND: In Germany, the 12-month prevalence of methamphetamine use among persons aged 15 to 34 is 1.9%. An increasing number of newborns are being born after a prenatal methamphetamine exposure (PME). In 2014, in the German state of Saxony, approximately four out of 1000 newborns were affected. METHODS: This systematic review (Prospero registration number CRD42017060536) includes publications that were published between January 1990 and November 2019. The purpose was to determine the effects of PME on the peri- and neonatal condition of the affected children and on their further long-term development. Observational studies with a control group were included in the review and examined for their methodological quality. RESULTS: 31 publications, which dealt with two prospective and six retrospective cohort studies, were included in the review. The studies involved a total of 4446 mother-child pairs with PME, compared with 43 778 pairs without PME. A metaanalysis revealed that PME was associated with, among other findings, lower birth weight (SMD = -0.348; 95% confidence interval [-0.777; 0.081]), shorter body length (SMD= -0.198 [-0.348; -0.047]), and smaller head circumference (SMD= -0.479 [-1.047; 0.089]). Some differences between the groups with and without PME persist into the toddler years. Moreover, children with PME much more commonly display psychological and neurocognitive abnormalities, which are more severe in children growing up in problematic surroundings (discord, violence, poverty, low educational level of the parent or caregiver). A limitation of this review is that not all studies employed an objective or quantitative measure of methamphet - amine use. CONCLUSION: The documented effects of PME on child development necessitate early treatment of the affected expectant mothers, children, and families. Emphasis should be placed on structured and interdisciplinary preventive measures for methamphetamine use.

[Association between Socioeconomic Status and Developmental Status: Data Linkage of Results of the Daycare and School Entry Health Examinations of a Saxon Birth Cohort Study]. / Zusammenhang zwischen sozioökonomischem Status und Entwicklungsstand ­ Datenlinkage von Ergebnissen der Kita- und Schulaufnahmeuntersuchung mit einer sächsischen Geburtskohortenstudie.

BACKGROUND: Child development is determined by both biological (e. g. gender, natal maturity) and psychosocial (e. g. socioeconomic status, daycare) factors. OBJECTIVES: To examine how familial socioeconomic status (SES) as well as biological and other psychosocial factors are associated with the state of development of 4- and 6-year-old children. METHODS: Data linkage of primary data from a birth cohort study and routine data from the Saxon public health departments on children born between 2007 and 2008, who underwent both daycare health examination and school entry health examination (N=615), was used to examine speech and motor skills, both fine and gross, for associations with psychosocial and biological factors. Potential associations were tested for significance and shown as odds ratios by using binary logistic regression. RESULTS: There were no noticeable problems in the development of the majority of Saxon children until school entry. Nevertheless, language seems to be a sensitive area of development, since 37% of the children showed problems at both time-points. Furthermore boys, preterm infants and children from a lower socio-economic class were more often affected by developmental delays, with preterm infants with low SES being at very high risk. Furthermore, the point of time of entering daycare seems to be of relevance for child development. CONCLUSIONS: The results are in line with national and international findings. An important new finding is the significantly increased likelihood of having developmental problems when biological and psychosocial risk factors coincide. However, longitudinal analyses are required to study developmental courses and to evaluate measures initiated to combat these issues.

Individual-Level Linkage of Primary and Secondary Data from Three Sources for Comprehensive Analyses of Low Birthweight Effects.

AIM OF THE STUDY: The linkage of primary and secondary data is becoming an increasingly popular approach in healthcare research, but involves some challenges for all involved parties, for example due to data protection requirements. The aim of this article is to systematically outline the methods used and experiences made during a cohort study in the field of pediatric health care research (EcoCare-PIn) that involved access to and linkage of three different data sources. Particular focus is placed on the necessary regulatory measures with regard to data access and data linkage as well as on data validation to ensure a correct linkage. METHODS: While complying with all relevant data protection requirements, the study realized an individual-level linkage of a) pseudonymized administrative health insurance data from a statutory health insurance on Saxon children born between 2007 and 2013, b) primary data collected via postal questionnaires from parents/caregivers and c) medical data from kindergarten- and school-entry-examinations of Saxon health authorities. The fundamental principle of the concept of data linkage was to strictly separate the sites of data collection and data analysis, which was realized through the involvement of a trust center. RESULTS: Challenges especially pertained to the extensive regulatory pre-requirements for data access as well as to data protection requirements while performing the study. Technical aspects and data validation also required a considerable share of attention and resources. A number of validation routines were applied to avoid incorrect data linkage and to ensure the high quality of the final dataset. Data validation included both plausibility checks within the primary data and consistency checks of information given in primary and secondary data. CONCLUSION: The linkage of primary and secondary data on the individual level offers great opportunities for using the strengths of different data sources synergistically and overcoming some of their limitations. Statutory health insurance data and medical data from kindergarten- and school-entry-examinations of Saxon health authorities are examples of already existing data sources that can complement cost-consuming primary data collections by valuable data sets and open up opportunities for longitudinal analysis.

[Intrauterine Growth Restriction: Transsectoral, Interdisciplinary and Multiprofessional Care for Pregnant Women and Newborns in a Feto-neonatal Pathway: A Project of the Innovationsfonds]. / Intrauterine Wachstumsrestriktion: Transsektorale, interdisziplinäre und multiprofessionelle Betreuung von Schwangeren und Neugeborenen im Feto-Neonat-Pfad: Ein Projekt des Innovationsfonds.

Intrauterine growth restriction (IUGR) is present in fetuses that do not achieve their full in-utero growth potential. IUGR needs to be discriminated from small for gestational age (SGA) because IUGR newborns in particular experience long-term side effects from their small growth. IUGR fetuses have a significantly increased risk of prematurity and a distinct risk profile compared to adequate-for-gestational-age preterm newborns. Complications of prematurity are more frequent, including bronchopulmonary dysplasia, intraventricular hemorrhage, and meconium ileus. IUGR newborns are at risk of long-term health issues like cerebral palsy, impaired lung function, and delayed speech development. Interdisciplinary and interprofessional care of IUGR pregnancies in the context of a standardized health care research project is feasible: Pregnant women at risk are identified, early therapy with acetylsalicylic acid is started as indicated, risk-adapted care at level III centers is organized including psychosocial interventions and neonatal consultations. Postnatally, integrated neonatal care focusing on parent-child interaction and optimized nutrition is a hallmark. Afterwards, in-depth pediatric follow-up visits with local pediatricians help to identify growth and neurodevelopment problems early. The effects, acceptance. and cost efficiency of this approach are evaluated prospectively as part of an Innovationsfonds project.

Impact of birthweight on health-care utilization during early childhood - a birth cohort study.

BACKGROUND: Comprehensive data are needed to evaluate the burden of low birthweight. Analysis of routine data on health-care utilization during early childhood were used to test the hypothesis that infants with low birthweight have (i) increased inpatient health-care utilization, (ii) higher hospital costs and (iii) different morbidity pattern in early childhood when compared with normal birthweight infants. METHODS: Children born between 2007 and 2013 that were insured at birth with the statutory health insurance AOK PLUS were included (N = 118,166, equaling 49% of the Saxon newborns) and classified into very low (< 1500 g, VLBW), low (1500-2499 g, LBW) birthweight and reference group (> 2500 g). Outcomes were: inpatient health-care utilization quantified by number and length of hospital stays; costs of hospitalizations including medication; reasons of hospitalizations for each year of life (YOL). RESULTS: 72, 38 and 22% of VLBW-, LBW- and reference group were hospitalized after perinatal period within the first YOL with a more than 5-fold increased risk in VLBW to be hospitalized for hemangioma, convulsions, hydrocephalus, hernia and respiratory problems. Median (IQR) cumulative cost of inpatient care during the first four YOLs was 2953 (1213-7885), 1331 (0-3451) and 0 (0-2062) Euro for respective groups. Inpatient early childhood health-care utilization (after first YOL) was higher in VLBW compared to healthy, normal birth weight infants (RR 3.92 [95%-CI 3.63, 4.23]), residents of rural areas (RR 1.37 [95%-CI 1.35, 1.40]) and in boys (RR 1.31 [95%-CI 1.29, 1.33]). CONCLUSION: This large population-based birth-cohort study indicates a high clinical and economic burden of low birthweight which is not restricted to the first year of life.

[Increasing Consumption of Crystal Meth in Saxony and its Risks for Mother and Child - Experiences at a Level I Perinatal Center from a Pediatric Viewpoint]. / Steigender Konsum von Crystal Meth in Sachsen und dessen Risiken für Mutter und Kind ­ Erfahrungen an einem Perinatalzentrum Level I aus pädiatrischer Sicht.

Over the past several years, the number of first-time users of methamphetamine considerably increased within the Free State of Saxony. This number also, and especially, includes women of child-bearing age and young mothers. A supportive intervention aimed at reducing the effects of drug abuse should begin in a timely way - during pregnancy at latest, but better before it. To develop an optimal care protocol for both the mother and her child, more knowledge regarding the personal conditions of the women as well as the specific features of later child development after prenatal methamphetamine exposure (PME) is vital. In this study, the data of 129 women and their newborns with PME who were admitted to a Level-1 perinatal center between 2007 and 2015 were analyzed. At delivery, two-thirds of the women were aged 20-30 years. Only 48% attended their first preventive examination in pregnancy within the first 12 weeks. Their children subsequently presented with heterogeneous withdrawal symptoms, and pathological findings of the heart, urogenital and central nervous system. The present data aims to sensitize pediatric and obstetric health professionals to the need for timely and adequate care and support. A pathway model of detoxification treatment for mother and child - "The Dresden Crystal Path" - is presented. It combines public and voluntary youth welfare organizations, public health authorities, a public drugs advisory service as well as medical care facilities. Moreover, it describes the coordination of different medical subspecialties such as pediatrics, obstetrics/gynecology and psychiatry.

Methamphetamine Consumption during Pregnancy - Effects on Child Health.

Methamphetamine abuse during pregnancy represents an emerging health care problem. The consequences are not only of relevance to the pregnant women, but also their unborn child. It is associated with an increased risk of preeclampsia and hypertension, fetal demise, preterm delivery, and intrauterine growth restriction. The deleterious effects of prenatal methamphetamine exposure on the developing fetal brain may lead to long-term neuro-developmental and behavioral problems.Given the current evidence, abuse of methamphetamine during pregnancy must be of utmost concern to health care professionals and to policy-makers. As it has been described for neonatal abstinence syndrome, a multi-professional team is required to improve care of affected women and families. A multi-disciplinary approach is needed, including good prenatal care of pregnant women, perinatal care by specialized obstetricians and neonatologists, and psychiatric treatment by an addiction specialist. Furthermore, families should be integrated into appropriate social support networks.For the development of a structured support program for pregnant women with methamphetamine consumption, methamphetamine use disorder should be considered as a disease that requires medical treatment as well as psychological and social support. The pregnancy should be considered as a window of opportunity to provide the required help.

Early comprehensive care of preterm infants-effects on quality of life, childhood development, and healthcare utilization: study protocol for a cohort study linking administrative healthcare data with patient reported primary data.

BACKGROUND: About 9 % of all children in Germany are born preterm. Despite significant improvements of medical care, preterm infants are at a greater risk to develop short and long term health complications. Negative consequences of preterm birth include neurodevelopmental disabilities, behavioral problems or learning disorders. Most data on effects of prematurity are derived from single or multi-center studies and not population-based. Since some of the long term problems of preterm delivery are associated with a disturbed parent-child interaction originating in the neonatal period, several intervention programs became available aiming to strengthen the early parent-child relationship. However, there is insufficient knowledge regarding the psychosocial and socioeconomic impact of these interventions. Prior to introducing them into routine care, those effects have to be rigorously evaluated. The population-based cohort study EcoCare-PIn (Early comprehensive Care of Preterm Infants-effects on quality of life, childhood development, and healthcare utilization) will investigate the following primary research questions: 1) What are the short- and long-term consequences of preterm birth with regard to parental stress, parent-child relationship, childhood development, quality of life and healthcare utilization including costs? 2) Does early family-centered psychosocial care prevent the hypothesized negative consequences of preterm birth on the above mentioned outcomes? METHODS/DESIGN: EcoCare-PIn examines the research questions by means of a linkage of a) pseudonymized administrative individual-level claims data from the German statutory health insurance AOK PLUS on approximately 140,000 children born between 2007 and 2013 in Saxony, and b) primary data collected from the parents/caregivers of all very low birth weight (<1,500 g; n = 1,000) and low birth weight infants (1,500 to 2,500 g; n = 5,500) and a matched sample of infants above 2,500 g birth weight (n = 10,000). DISCUSSION: In Saxony, approximately 50 % of all individuals are insured at the AOK PLUS. The linkage of patient-level administrative and primary data is a novel approach in neonatal research and probably the only way to overcome shortcomings of studies solely relying on one data source. The study results are based on an observation period of up to 8 years and will directly inform perinatal healthcare provision in Saxony and Germany as a whole.

Alcohol-induced impairment in adolescents admitted to inpatient treatment after heavy episodic drinking: effects of age and gender.

OBJECTIVE: In Germany and many other countries, the number of adolescent heavy episodic drinking-induced hospital admissions (HEDHA) in pediatric units markedly increased during the past decade. A low level of response to alcohol in young adults is associated with high risk for later development of alcohol use disorders (AUDs). METHOD: We performed a retrospective chart review of all 1,123 HEDHA cases in adolescents aged 11-17 years who were admitted to one of the pediatric inpatient units covering the cities of Dresden, Pirna, and Rostock, Germany, between 2000 and 2008. Blood alcohol concentration (BAC) and Glasgow Coma Scale (GCS) measures on admission were documented in 846 cases. RESULTS: The mean (SD) BAC was 155 (50) mg/100 ml full blood, and M (SD) GCS was 12.21 (3.02). These parameters were negatively correlated with each other (r = -.256, p < .001), indicating more impairment at higher BACs. To describe a numerical estimate of how severely a subject was compromised relative to his BAC, the GCS scores were inverted (making high scores indicate severe impairment) and divided by BAC. The resulting alcohol-induced impairment index (AIII) was significantly influenced by an interaction between age and gender, decreasing with age in boys but increasing in girls. CONCLUSIONS: During adolescence, alcohol-induced impairment develops differently in boys and girls, which may be because of the girls' developmental edge. The high variability of observed AIII might help to predict the risk for later AUDs in the emergency department, simply by measuring BAC and GCS.

Influences of a dedicated parental training program on parent-child interaction in preterm infants.

OBJECTIVE: To investigate influences on the interaction between preterm infants and their parents by a dedicated parental training program on the care of preterm infants. METHODS: Standardized scenarios of mother-child interactions (50 mother-child dyads of very low birth weight infants (VLBWI), birth weight<1500g) were videotaped in two perinatal centers (PC-A, PC-B). The videos were reviewed and scored using a standardized instrument. In both centers, parents were integrated in the daily care by pediatric nurses, while additionally PC-A had a structured parental training program. RESULTS: PC-A and PC-B were comparable regarding patient spectrum and number of admissions of VLBWIs/year. Both centers had similar care values with respect to the "baby friendly" initiative. No significant differences were seen in characteristics of patients (gestational age, birth weight, postnatal age) and mothers (age, parity, marital status, professions). However, in scoring the mother-child interactions significant differences were observed: In contrast to PC-B the recorded behavior in mother-child dyads of PC-A was significantly more often scored as interaction-oriented. CONCLUSION: A dedicated, structured, and actively encouraging training program for parents of preterm infants was found to be more strongly correlated toward neurodevelopmental enhancing mother-child-interactions than an approach of merely integrating parents into daily care routine.

A retrospective analysis of psychosocial risk factors modulating adolescent alcohol binge drinking.

BACKGROUND/AIMS: Adolescent alcohol binge-induced hospital admissions (BIHAs) are an increasing problem in Europe. We investigated whether psychosocial factors (e.g., drinking situations, drinking occasions and neighborhood unemployment) are associated with particularly risky patterns of alcohol or substance use. METHOD: We performed a systematic retrospective chart review of all the respective cases in 2003-2008 (n = 586; age range: 12-17 years) from both pediatric hospitals in the city of Dresden, Germany. RESULTS: The vast majority of adolescent BIHAs were associated with drinking together with peers at weekend parties. Compared to this 'typical' drinking pattern, adolescents drinking 'atypically' (i.e., drinking either alone, to cope or despite the fact that the next day was a school/work day) more often had already used alcohol and illegal substances before and were more often diagnosed with substance use disorders and other mental disorders prior to BIHA. The unemployment rate in the patients' neighborhood was positively related to the incidence proportion of adolescent BIHAs in the respective subdistricts (r(s) = 0.61). CONCLUSION: Adolescent atypical drinking may indicate an increased risk for the development of alcohol and substance use disorders. This information is quickly accessible and can alert clinicians to initiate psychosocial aftercare; their infrastructure should address the strong relation between BIHA probability and neighborhood unemployment rates.

[Health insurance expenses for children in the first five years of life - a cohort-based analysis]. / Ausgaben einer Krankenkasse für Kinder in den ersten fünf Lebensjahren - eine kohortenbasierte Analyse.

INTRODUCTION: The development of paediatrics is characterised by several changes in the past few years, concerning, in particular holistic treatments or preventive check-ups, but also the transfer of treatment from the inpatient to the outpatient sector. There are no reference values for assessing emerging health insurance expenses. The aim of this study was to obtain a frame of reference for the costs of the treatment for neonates, infants, and young children using the example of the expenditures of one health insurance fund. METHODS: The individual health insurance expenditures were analysed for the first five years of life of children insured with the AOK PLUS in Saxony, Germany, in 2005. Costs of hospital treatment, ambulatory care, remedies, tools, medicines and care were included. RESULTS: The costs per insured child and year amounted to approximately 1,277 Euro (N = 11,147), with the highest costs arising in the first two years. 858 Euro were spent annually for an "average" child; 5,691 Euro per year incurred for a child with special medical needs. DISCUSSION: The present cost analysis describes both the height and structure of a health insurance's spendings on children within the first five years of their life in consideration of regional medical care offers. The question of whether this analysis provides valid reference values for other health insurances or other service areas will have to be answered by other analyses.

Hypothenar hammer syndrome: a multicenter case-control study.

BACKGROUND: The rarely diagnosed hypothenar hammer syndrome (HHS) is due to vascular damage to the distal part of the ulnar artery probably caused by acute or repetitive blunt trauma to the hypothenar region. To date, mainly case reports have been published, while epidemiological data are almost absent. AIM: To identify potential risk factors for HHS. METHOD: An interview-based multicenter case-control study of 71 patients with HHS and 105 matched controls was conducted with standardized questions regarding disease specific variables, occupation, exposure of the hands to different types of trauma in occupational and leisure context. Medical data were verified from individual medical records. RESULTS: Multivariable logistic regression analysis revealed that using the hand as a hammer on a daily basis (adjusted odds ratio [aOR] 17.04, 95% CI 5.51-52.67) daily pressure to the palm of the hand (aOR 4.96, 95% CI 1.39-17.71), and daily exposure to vibrating tools (aOR 3.41, 95% CI 1.03-11.31) were significant risk factors for HHS. CONCLUSIONS: This investigation represents one of the largest groups of patients with HHS described so far. Work-related repeated blunt trauma to the palm of the hand significantly increases the risk of HHS.

Facets of protein assembly on nanostructured titanium oxide surfaces.

One key for the successful integration of implants into the human body is the control of protein adsorption by adjusting the surface properties at different length scales. This is particularly important for titanium oxide, one of the most common biomedical interfaces. As for titania (TiO(2)) the interface is largely defined by its crystal surface structure, it is crucial to understand how the surface crystallinity affects the structure, properties and function of protein layers mediating subsequent biological reactions. For rutile TiO(2) we demonstrate that the conformation and relative amount of human plasma fibrinogen (HPF) and the structure of adsorbed HPF layers depend on the crystal surface nanostructure by employing thermally etched multi-faceted TiO(2) surfaces. Thermal etching of polycrystalline TiO(2) facilitates a nanoscale crystal faceting and, thus, the creation of different surface nanostructures on a single specimen surface. Atomic force microscopy shows that HPF arranges into networks and thin globular layers on flat and irregular crystal grain surfaces, respectively. On a third, faceted category we observed an alternating conformation of HPF on neighboring facets. The bulk grain orientation obtained from electron backscatter diffraction and thermodynamic mechanisms of surface reconstruction during thermal etching suggest that the grain and facet surface-specific arrangement and relative amount of adsorbed proteins depend on the associated free crystal surface energy. The implications for potentially favorable TiO(2) crystal facets regarding the inflammatory response and hemostasis are discussed with a view to the advanced surface design of future implants.

Morphology and structure of polymer layers protecting dental enamel against erosion.

OBJECTIVES: Human dental erosion caused by acids is a major factor for tooth decay. Adding polymers to acidic soft drinks is one important approach to reduce human dental erosion caused by acids. The aim of this study was to investigate the thickness and the structure of polymer layers adsorbed in vitro on human dental enamel from polymer modified citric acid solutions. METHODS: The polymers propylene glycol alginate (PGA), highly esterified pectin (HP) and gum arabic (GA) were used to prepare polymer modified citric acids solutions (PMCAS, pH 3.3). With these PMCAS, enamel samples were treated for 30, 60 and 120s respectively to deposit polymer layers on the enamel surface. Profilometer scratches on the enamel surface were used to estimate the thickness of the polymer layers via atomic force microscopy (AFM). The composition of the deposited polymer layers was investigated with X-ray photoelectron spectroscopy (XPS). In addition the polymer-enamel interaction was investigated with zeta-potential measurements and scanning electron microscopy (SEM). RESULTS: It has been shown that the profilometer scratch depth on the enamel with deposited polymers was in the range of 10nm (30s treatment time) up to 25nm (120s treatment time). Compared to this, the unmodified CAS-treated surface showed a greater scratch depth: from nearly 30nm (30s treatment time) up to 60nm (120s treatment time). Based on XPS measurements, scanning electron microscopy (SEM) and zeta-potential measurements, a model was hypothesized which describes the layer deposited on the enamel surface as consisting of two opposing gradients of polymer molecules and hydroxyapatite (HA) particles. SIGNIFICANCE: In this study, the structure and composition of polymer layers deposited on in vitro dental enamel during treatment with polymer modified citric acid solutions were investigated. Observations are consistent with a layer consisting of two opposing gradients of hydroxyapatite particles and polymer molecules. This leads to reduced erosive effects of citric acid solutions on dental enamel surfaces.

Acids with an equivalent taste lead to different erosion of human dental enamel.

OBJECTIVES: The consumption of acidic soft drinks may lead to demineralization and softening of human dental enamel, known as dental erosion. The aims of this in vitro study were to determine: (i) if different acids with a similar sensorial acidic taste lead to different hardness loss of enamel and (ii) if the fruit acids tartaric, malic, lactic or ascorbic acid lead to less hardness loss of enamel than citric or phosphoric acid when their concentration in solution is based on an equivalent sensorial acidic taste. METHODS: Enamel samples of non-erupted human third molars were treated with acidic solutions of tartaric (TA), malic (MA), lactic (LA), ascorbic (AA), phosphoric (PA) and citric (CA) acids with a concentration that gave an equivalent sensorial acidic taste. The acidic solutions were characterized by pH value and titratable acidity. Atomic force microscopy (AFM) based nanoindentation was used to study the nano mechanical properties and scanning electron microscopy (SEM) was used to study the morphology of the treated enamel samples and the untreated control areas, respectively. RESULTS: The investigated acids fell into two groups. The nano hardnesses of MA, TA and CA treated enamel samples (group I) were statistically significantly greater (p<0.05) than the nano hardnesses of PA, AA and LA treated enamel samples (group II). Within each group the nano hardness was not statistically significantly different (p>0.05). The SEM micrographs showed different etch prism morphologies depending on the acid used. SIGNIFICANCE: In vitro, the acids investigated led to different erosion effects on human dental enamel, despite their equivalent sensorial acidic taste. This has not been reported previously.

How the surface nanostructure of polyethylene affects protein assembly and orientation.

Protein adsorption plays a key role in the biological response to implants. We report how nanoscale topography, chemistry, crystallinity, and molecular chain anisotropy of ultrahigh molecular weight polyethylene (UHMWPE) surfaces affect the protein assembly and induce lateral orientational order. We applied ultraflat, melt drawn UHMWPE films to show that highly oriented nanocrystalline lamellae influence the conformation and aggregation into network structures of human plasma fibrinogen by atomic force microscopy with unprecedented clarity and molecular resolution. We observed a transition from random protein orientation at low concentrations to an assembly guided by the UHMWPE surface nanotopography at a close to full surface coverage on hydrophobic melt drawn UHMWPE. This assembly differs from the arrangement at a hydrophobic, on the nanoscale smooth UHMWPE reference. On plasma-modified, hydrophilic melt drawn UHMWPE surfaces that retained their original nanotopography, the influence of the nanoscale surface pattern on the protein adsorption is lost. A model based on protein-surface and protein-protein interactions is proposed. We suggest these nanostructured polymer films to be versatile model surfaces to provide unique information on protein interactions with nanoscale building blocks of implants, such as nanocrystalline UHMWPE lamellae. The current study contributes to the understanding of molecular processes at polymer biointerfaces and may support their future design and molecular scale tailoring.