The effectiveness of allied health and nurse practitioner models-of-care in managing musculoskeletal conditions in the emergency department: a systematic review and meta-analysis.

BACKGROUND: Musculoskeletal conditions are the most common health condition seen in emergency departments. Hence, the most effective approaches to managing these conditions is of interest. This systematic review aimed to evaluate the effectiveness of allied health and nursing models of care for the management of musculoskeletal pain in ED. METHODS: MEDLINE, EMBASE, CINAHL and LILACS databases were searched from inception to March 2023 for published randomised trials that compared the effectiveness of allied health and nursing models of care for musculoskeletal conditions in ED to usual ED care. Trials were eligible if they enrolled participants presenting to ED with a musculoskeletal condition including low back pain, neck pain, upper or lower limb pain and any soft tissue injury. Trials that included patients with serious pathology (e.g. malignancy, infection or cauda equina syndrome) were excluded. The primary outcome was patient-flow; other outcomes included pain intensity, disability, hospital admission and re-presentation rates, patient satisfaction, medication prescription and adverse events. Two reviewers performed search screening, data extraction, quality and certainty of evidence assessments. RESULTS: We identified 1746 records and included 5 randomised trials (n = 1512 patients). Only one trial (n = 260) reported on patient-flow. The study provides very-low certainty evidence that a greater proportion of patients were seen within 20 min when seen by a physician (98%) than when seen by a nurse (86%) or physiotherapist (77%). There was no difference in pain intensity and disability between patients managed by ED physicians and those managed by physiotherapists. Evidence was limited regarding patient satisfaction, inpatient admission and ED re-presentation rates, medication prescription and adverse events. The certainty of evidence for secondary outcomes ranged from very-low to low, but generally did not suggest a benefit of one model over another. CONCLUSION: There is limited research to judge the effectiveness of allied health and nursing models of care for the management of musculoskeletal conditions in ED. Currently, it is unclear as to whether allied health and nurse practitioners are more effective than ED physicians at managing musculoskeletal conditions in ED. Further high-quality trials investigating the impact of models of care on service and health outcomes are needed.

Induced leg length inequality affects pelvis orientation during upright standing immediately following a sit-to-stand transfer: a pre-post measurement study.

BACKGROUND: Leg length inequality (LLI) greater than 20 mm has been associated with low back pain (LBP) and its correction is clinically recommended. Much less is known about the biomechanical effects that LLI below 15 mm has on pelvis orientation. METHODS: Twenty-two adult participants (8 female) aged between 18 and 30 years without LBP were enrolled in the study and completed a series of sit-to-stand trials with no heel-lift (0 mm baseline) and heel-lifts of varying heights (5, 9 and 12 mm) placed in their right shoe. Three-dimensional kinematic data were obtained from the lower extremities, pelvis and thorax. Additional kinematic data were obtained from the left and right sides of the pelvis. The global orientation of the whole pelvis and relative orientation between the left and right sides of the pelvis were obtained in upright standing immediately upon completion of the sit-to-stand movement. Repeated measures ANOVAs were used to detect differences in sample means across the different levels of heel-lift (0, 5, 9, and 12 mm). The tests for within-subject effects determined overall significant differences between the means at the different levels of heel-lift induced LLI. Partial Eta-Squared was used to express the size for the main effect of heel-lift height. For each level of heel-lift, the estimated marginal mean and 95% confidence interval (95%CI) values of pelvis angles were illustrated graphically. RESULTS: Left frontal plane rotation of the pelvis increased (p = 0.001), that is, the left side of the pelvis was lower than the right side of the pelvis, and anterior tilt of the pelvis decreased (p = 0.020) with a heel-lift height (applied on the right) as low as 5 mm. A significant main effect of heel-lift was only observed for the norm of rotations about all three axes for relative-pelvis orientation (p = 0.034). Post-hoc analyses did not reveal any statistically significant differences between the heel-lifts and the 0 mm baseline (p≥0.072). CONCLUSION: These findings suggest that correcting leg length inequality below the recommended threshold of 20 mm may influence pelvic orientation. Future work can investigate the effects of the altered orientations on spine loading and the clinical effects of corrections to minor leg length inequality.

The Implementation and Utilization of Wastewater-Based Epidemiology: Experiences From a Local Health Department.

Wastewater-based epidemiology has increasingly demonstrated its importance in addressing public health threats. The COVID-19 pandemic brought forth funding for public health agencies to conduct wastewater-based epidemiology. Using a team with diverse skills, a local health department utilized this funding to regularly monitor SARS-CoV-2 in wastewater on university campuses, a K-12 campus, an inpatient psychiatric facility, and a long-term care facility. Between September 2021 and May 2022, more than 760 wastewater samples were collected of which 102 (13.4%) were above a predetermined threshold. When sites exceeded that threshold, local health department staff provided testing resources. Wastewater-based epidemiology is a useful surveillance program that can be effectively conducted by local health departments when provided with funding and a skilled workforce.

Exceeding 2-h sedentary time per day is not associated with moderate to severe spinal pain in 11- to 13-year-olds: a cross-sectional analysis.

Neck, mid-back and low back pain, collectively known as spinal pain, become more common with increasing age across childhood and adolescence. A common belief among the general community is that sedentary time, including screen time, in adolescents is associated with spinal pain. We aimed to investigate whether exceeding 2-h of sedentary time per day is associated with moderate to severe spinal pain in a sample of Danish adolescents aged 11-13 years. We performed a cross-sectional analysis of the SPACE study baseline data (2010). Adolescents self-reported their spinal pain (outcome) via the Young Spine Questionnaire and duration of engagement in sedentary behaviours (exposure). We provide estimates of associations as odds ratios with 95% confidence intervals, stratified by age and sex. The sample comprised 1,303 adolescents (48.7% female, mean age 12.5 years, range 10.9-14.3 years). Approximately 9 out of 10 adolescents exceeded 2-h sedentary time on weekdays outside of school (88.9%) and weekend days (89.9%). Close to one-quarter, 23.3% (95%CI: 21.0-25.6), of participants experienced moderate to severe spinal pain. We found no association between exceeding 2-h sedentary time per day and experiencing moderate to severe spinal pain; odds ratios ranged from 0.34 (95%CI: 0.04-3.20) to 4.65 (95%CI: 0.26-82.44).Conclusion: We found no association between exceeding 2- or 5-h of sedentary time per day and moderate to severe spinal pain in this sample of 11-13-year-old Danish adolescents. Our cross-sectional analysis does not consider the longitudinal or complex sequences of events necessary to address predictive or causal questions. What is Known: • Up to a third of adolescents experience moderate to severe spinal pain, predisposing them to chronic spinal pain in adulthood. • Frequent and excessive sedentary time is associated with poor overall health in adolescents; there is conflicting evidence to suggest whether it is also related to spinal pain. What is New: • We found no association between sedentary time and moderate to severe spinal pain in 11- to 13-year-old Danes.

Spinal pain in childhood: prevalence, trajectories, and diagnoses in children 6 to 17 years of age.

This study aimed to investigate the trajectories of spinal pain frequency from 6 to 17 years of age and describe the prevalence and frequency of spinal pain and related diagnoses in children following different pain trajectories. First through fifth-grade students from 13 primary schools were followed for 5.5 years. Occurrences of spinal pain were reported weekly via text messages. Children reporting spinal pain were physically evaluated and classified using International Classification of Disease criteria. Trajectories of spinal pain frequency were modeled from age 6 to 17 years with latent class growth analysis. We included data from 1556 children (52.4% female, mean (SD) baseline age = 9.1 (1.9) years) and identified 10,554 weeks of spinal pain in 329,756 weeks of observation. Sixty-three percent of children reported one or more occurrences of spinal pain. We identified five trajectories of spinal pain frequency. Half the children (49.8%) were classified as members of a "no pain" trajectory. The remaining children followed "rare" (27.9%), "rare, increasing" (14.5%), "moderate, increasing" (6.5%), or "early-onset, decreasing" (1.3%) spinal pain trajectories. The most common diagnoses in all trajectory groups were non-specific (e.g., "back pain"). Tissue-specific diagnoses (e.g., muscle strain) were less common and pathologies (e.g., fracture) were rare.  Conclusion: From childhood through adolescence, spinal pain was common and followed heterogeneous courses comprising stable, increasing, and early-onset trajectories. These findings accord with recommendations from adult back pain guidelines that most children with spinal pain can be reassured that they do not have a serious disease and encouraged to stay active. What is Known: • Spinal pain imposes a large burden on individuals and society. • Although many people first experience the condition in childhood, little is known about the developmental trajectories of spinal pain from childhood to adolescence. What is New: • Data from 1556 children and 329,756 participant weeks showed five unique spinal pain trajectories from 6 to 17 years: most children rarely reported spinal pain, while one in five followed increasing or early-onset trajectories. • Most pain occurrences were non-specific; pathological diagnoses were rare.

Paramedic management of back pain: a scoping review.

BACKGROUND: Research examining paramedic care of back pain is limited. OBJECTIVE: To describe ambulance service use and usual paramedic care for back pain, the effectiveness and safety of paramedic care of back pain, and the characteristics of people with back pain who seek care from paramedics. METHODS: We included published peer-reviewed studies of people with back pain who received any type of paramedic care on-scene and/or during transport to hospital. We searched MEDLINE, EMBASE, CINAHL, Web of Science and SciELO from inception to July 2022. Two authors independently screened and selected the studies, performed data extraction, and assessed the methodological quality using the PEDro, AMSTAR 2 and Hawker tools. This review followed the JBI methodological guidance for scoping reviews and PRISMA extension for scoping reviews. RESULTS: From 1987 articles we included 26 articles (25 unique studies) consisting of 22 observational studies, three randomised controlled trials and one review. Back pain is frequently in the top 3 reasons for calls to an ambulance service with more than two thirds of cases receiving ambulance dispatch. It takes ~ 8 min from time of call to an ambulance being dispatched and 16% of calls for back pain receive transport to hospital. Pharmacological management of back pain includes benzodiazepines, NSAIDs, opioids, nitrous oxide, and paracetamol. Non-pharmacological care is poorly reported and includes referral to alternate health service, counselling and behavioural interventions and self-care advice. Only three trials have evaluated effectiveness of paramedic treatments (TENS, active warming, and administration of opioids) and no studies provided safety or costing data. CONCLUSION: Paramedics are frequently responding to people with back pain. Use of pain medicines is common but varies according to the type of back pain and setting, while non-pharmacological care is poorly reported. There is a lack of research evaluating the effectiveness and safety of paramedic care for back pain.

Microstructural heterogeneity of the collagenous network in the loaded and unloaded periodontal ligament and its biomechanical implications.

The periodontal ligament (PDL) is a highly heterogeneous fibrous connective tissue and plays a critical role in distributing occlusal forces and regulating tissue remodeling. Its mechanical properties are largely determined by the extracellular matrix, comprising a collagenous fiber network interacting with the capillary system as well as interstitial fluid containing proteoglycans. While the phase-contrast micro-CT technique has portrayed the 3D microscopic heterogeneity of PDL, the topological parameters of its network, which is crucial to understanding the multiscale constitutive behavior of this tissue, has not been characterized quantitatively. This study aimed to provide new understanding of such microscopic heterogeneity of the PDL with quantifications at both tissue and collagen network levels in a spatial manner, by combining phase-contrast micro-CT imaging and a purpose-built image processing algorithm for fiber analysis. Both variations within a PDL and among the PDL with different shapes, i.e. round-shaped and kidney-shaped PDLs, are described in terms of tissue thickness, fiber distribution, local fiber densities, and fiber orientation (namely azimuthal and elevation angles). Furthermore, the tissue and collagen fiber network responses to mechanical loading were evaluated in a similar manner. A 3D helical alignment pattern was observed in the fiber network, which appears to regulate and adapt a screw-like tooth motion under occlusion. The microstructural heterogeneity quantified here allows development of sample-specific constitutive models to characterize the PDL's functional and pathological loading responses, thereby providing a new multiscale framework for advancing our knowledge of this complex limited mobility soft-hard tissue interface.

Clinicians' Ability to Detect a Palpable Difference in Spinal Stiffness Compared With a Mechanical Device.

OBJECTIVE: The purpose of this study was to quantify the threshold at which clinicians can detect a difference in spinal stiffness of the thoracic and lumbar spine via palpation and then determine if this detection threshold would affect a clinician's ability to identify changes in spinal stiffness as measured by an objective instrument. METHODS: In this study, the threshold at which a change in spinal stiffness was detected was quantified in 12 experienced clinicians (physical therapists and doctors of chiropractic) by changing the differential stiffness in 2 inflatable targets until the clinician could no longer identify which was stiffer. In the second part of the study, clinicians then were asked to palpate pre-identified pairs of vertebrae in an asymptomatic volunteer and to identify the stiffer of the pair (T7 and L3, T7 and L4, L3 and L4), and the biomechanical stiffness of each vertebral pair was quantified objectively by a validated instrument. RESULTS: The mean stiffness detection threshold for the clinicians was 8%. Objective measurement of the stiffness differential between vertebral pairs was 30% for T7* and L3, 20% for T7* and L4, and 10% for L3* and L4 (*denotes the stiffer of the pair). Ten of 12 clinicians correctly identified T7 as stiffer when compared with L3 and T7 as stiffer than L4. Alternatively, when the differential vertebral pair stiffness was similar to the stiffness detection threshold (~8%), clinicians were less successful in identifying the stiffer vertebra of the pair; 4 of 12 clinicians correctly identified L3 as being stiffer compared with L4. CONCLUSION: These results suggest that the physiological limits of human palpation may limit the ability of clinicians to identify small alterations in spine stiffness.

Microcomputed Tomography Calibration Using Polymers and Minerals for Enamel Mineral Content Quantitation.

OBJECTIVE: The aim of this paper was to develop calibration standards (CSs) that are readily available for clinical researchers for the quantitation of enamel mineral content. METHOD: Polyethylene terephthalate (PET), acetal, polyphenylene sulfide (PPS), selenite, Egyptian alabaster, aragonite, and fluorite were fashioned into discs, and their densities were measured and stacked for microcomputed tomography examination. Frame averaging, flat-field correction, pre-filtration, and beam-hardening correction were applied. CSs were checked for homogeneity. The linear relationship between the mean greyscale value (GSV) of each disc and its physically calculated density was explored, and reproducibility was tested. A calibration function was established and then validated using a bovine enamel disc and sound enamel of extracted human premolar teeth. RESULTS: Measured densities were PET (ρ = 1.38 g/cm3), acetal (ρ = 1.41 g/cm3), PPS (ρ = 1.64 g/cm3), selenite (ρ = 2.24 g/cm3), Egyptian alabaster (ρ = 2.7 g/cm3), aragonite (ρ = 2.72 g/cm3), and fluorite (ρ = 3.11 g/cm3). Examination of the profile sections of CSs confirmed the uniformity of GSVs with minimal beam-hardening effect. A squared Pearson correlation coefficient of R2 = 0.994 was determined between the mean GSV of each CS and its calculated density and was reproduced at different settings with R2 >0.99. A linear regression equation of density (y) versus GSV (x) was established using the least squares regression equation method. The estimated density of the bovine enamel disc (2.48 g/cm3) showed high accuracy when compared to the physically measured value (2.45 g/cm3). The -relative error was 1.2%. Densities of sound enamel in the extracted human premolar teeth were 2.6-3.1 g/cm3. CONCLUSIONS: This is a simple, valid, and reproducible method to quantitate enamel mineral content. This simple, yet accurate system could be used to expand knowledge in the field of enamel caries research.

Prevalence and practice characteristics of urban and rural or remote Australian chiropractors: Analysis of a nationally representative sample of 1830 chiropractors.

OBJECTIVE: To determine the prevalence and clinical management characteristics of chiropractors practising in urban and rural or remote Australia. DESIGN: A cross-sectional analysis of the Australian Chiropractic Research Network project data. SETTING: Nationally representative sample of registered chiropractors practising in Australia. PARTICIPANTS: Chiropractors who participated in the Australian Chiropractic Research Network project and answered a question about practising in urban or rural or remote areas in the practitioner questionnaire. MAIN OUTCOME MEASURE: The demographics, practice characteristics and clinical management of chiropractors. RESULTS: The majority of chiropractors indicated that they practise in urban areas only, while 22.8% (n = 435) practice in rural or remote areas only and 4.0% (n = 77) practice in both urban and rural or remote areas. Statistically significant predictors of chiropractors who practice in rural or remote areas, as compared to urban areas, included more patient visits per week, practising in more than one location, no imaging facilities on site, often treating degenerative spinal conditions or migraine, often treating people aged over 65 years, frequently treating Aboriginal and Torres Strait Islander people and frequently using biomechanical pelvic blocking or the sacro-occipital technique. CONCLUSION: A substantial number of chiropractors practice in rural or remote Australia and these rural or remote-based chiropractors are more likely to treat a wide range of musculoskeletal cases and include an Indigenously diverse group of patients than their urban-located colleagues. Unique practice challenges for rural or remote chiropractors include a higher workload and a lack of diagnostic tools. Chiropractors should be acknowledged and considered within rural or remote health care policy and service provision.

Characterization of inter-crystallite peptides in human enamel rods reveals contribution by the Y allele of amelogenin.

Proteins of the inter-rod sheath and peptides within the narrow inter-crystallite space of the rod structure are considered largely responsible for visco-elastic and visco-plastic properties of enamel. The present study was designed to investigate putative peptides of the inter-crystallite space. Entities of 1-6 kDa extracted from enamel rods of erupted permanent teeth were analysed by mass spectrometry (MS) and shown to comprise N-terminal amelogenin (AMEL) peptides either containing or not containing exon 4 product. Other dominant entities consisted of an N-terminal peptide from ameloblastin (AMBN) and a series of the most hydrophobic peptides from serum albumin (ALBN). Amelogenin peptides encoded by the Y-chromosome allele were strongly detected in Enamel from male teeth. Location of N-terminal AMEL peptides as well as AMBN and ALBN, between apatite crystallites, was disclosed by immunogold scanning electron microscopy (SEM). Density plots confirmed the relative abundance of these products including exon 4+ AMEL peptides that have greater capacity for binding to hydroxyapatite. Hydrophilic X and Y peptides encoded in exon 4 differ only in substitution of non-polar isoleucine in Y for polar threonine in X with reduced disruption of the hydrophobic N-terminal structure in the Y form. Despite similarity of X and Y alleles of AMEL the non-coding region upstream from exon 4 shows significant variation with implications for segregation of processing of transcripts from exon 4. Detection of fragments from multiple additional proteins including keratins (KER), fetuin A (FETUA), proteinases and proteinase inhibitors, likely reflect biochemical events during enamel formation.

Relationship between growth, maturation and musculoskeletal conditions in adolescents: a systematic review.

OBJECTIVE: To determine whether there is a relationship between physical growth and development, as determined by markers of biological maturation, and musculoskeletal conditions in adolescents. DESIGN: Systematic review. DATA SOURCES: Electronic databases (PubMed, EMBASE and the Cumulative Index to Nursing and Allied Health Literature) were searched up to 6 September 2017. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Studies that evaluated the association between biological maturation or growth and musculoskeletal conditions in adolescents (chronological age 10-19 years). RESULTS: From 20 361 titles identified by the searches, 511 full-text articles were retrieved and assessed for eligibility; 56 studies, all at high risk of bias, evaluating the relationship between maturation and/or growth and musculoskeletal conditions were included. A total of 208 estimates of association were identified across the included studies, which generally indicated no association or an unclear association between maturation, growth and musculoskeletal conditions. SUMMARY/CONCLUSIONS: While the relationship between maturation, growth and musculoskeletal conditions remains plausible, the available evidence is not supportive. The current body of knowledge is at high risk of bias, which impedes our ability to establish whether biological maturity and growth are independent risk factors for musculoskeletal conditions.

Correlations Between Individuals' Characteristics and Spinal Stiffness in Individuals With and Without Back Pain: A Combined Analysis of Multiple Data Sets.

OBJECTIVE: The purpose of this study was to describe the correlations between individual characteristics and spinal stiffness as measured with different spinal stiffness measurement devices in individuals with and without back pain. METHODS: A secondary analysis of 3 adult data sets obtained using 3 different devices, in 2 spinal regions, from a total of 5 separate cross-sectional studies was conducted. Differences in spinal stiffness between men and women and in the strength of correlations among spinal stiffness and age and anthropometric characteristics were evaluated using either the t test for independent samples, Pearson's correlation coefficient, or Kendall's τ rank correlation coefficient. RESULTS: As expected, results varied between data sets; however, few factors had consistent correlations. Specifically, spinal stiffness was significantly lower in women than men in all 3 data sets. Height was positively correlated with spinal stiffness across all data sets. Although weight was correlated with thoracic stiffness, its correlation with lumbar stiffness varied. In 2 data sets, body mass index was inversely associated with lumbar spinal stiffness, whereas results from the thoracic spine region revealed a positive correlation. The results for 1 data set suggest that physiological measurement evaluating body weight distribution may also affect spinal stiffness; however, the specific correlation remains unclear. CONCLUSION: Despite data set differences, significant correlations were observed, indicating that participants' characteristics appear to affect spinal stiffness measurement.

Removal of dentin non-collagenous structures results in the unraveling of microfibril bundles in collagen type I.

AIMS: The structural organization of collagen from mineralized tissues, such as dentin and bone, has been a topic of debate in the recent literature. Recent reports have presented novel interpretations of the complexity of collagen type I at different hierarchical levels and in different tissues. Here, we investigate the nanostructural organization of demineralized dentin collagen following the digestion of non-collagenous components with a trypsin enzyme. MATERIALS AND METHODS: Dentin specimens were obtained from healthy third-molars, cut into small cubes, and polished down to 1 µm roughness. Samples were then demineralized with 10% citric acid for 2 min. Selected specimens were further treated with a solution containing 1 mg/ml trypsin for 48 hours at 37 °C (pH 7.9-9.0). Both untreated and trypsin digested samples were analyzed using SDS-PAGE, Field Emission Scanning Electron Microscopy (FE-SEM), and nanoindentation, where surface hardness and creep properties were compared before and after treatments. RESULTS: FE-SEM images of demineralized dentin showed the banded morphology of D-periodical collagen type I, which upon enzymatic digestion with trypsin appeared to dissociate longitudinally, consistently unraveling ~20 nm structures (microfibril bundles). Such nanoscale structures, to the best of our knowledge, have not been characterized in dentin previously. Mechanical characterization via nanoindentation showed that the unraveling of such microfibril bundles affected the creep displacement and creep rate of demineralized dentin. CONCLUSION: In summary, our results provide novel evidence of the organization of collagen type I from dentin, which may have important implications for the interaction of dental materials with the organic dentin matrix and the mechanical properties of mineralized tissues.

Pain and Moderate to Vigorous Physical Activity in Adolescence: An International Population-Based Survey.

OBJECTIVE: To evaluate whether individual types of pain (headache, stomach-ache, and backache) or multiple pains affect the odds of young people achieving the recommended 60 minutes of moderate to vigorous physical activity (MVPA) per day in a large representative sample. DESIGN: Multicenter cross-sectional survey. SETTING: Twenty-eight countries across Europe and North America. SUBJECTS: Adolescents (N = 242,103). METHODS: An analysis of data collected in two waves (2001/02 and 2005/06) of the health behavior in school-aged children (HBSC) study was performed. Survey questions included the HBSC symptoms checklist and the amount of regular physical activity. Multilevel logistic regression was used to account for clustering effect of MVPA within countries. Models investigated the relationship between pain and physical activity, adjusted for the HBSC study year. Six models were conducted separately for gender and age-group (11, 13, and 15 years) strata. RESULTS: In general, the presence of pain was associated with reduced physical activity. Headache alone was associated with reduced physical activity in all six strata (odd ratios 0.77-0.84), stomach-ache alone in five strata (0.77-0.92), and backache alone in four strata (0.86-0.96). In 11- and 13-year-old girls, headache, stomach-ache, and backache, individually and in combination, were associated with decreased odds of being physically active (odds ratios ranging from 0.73 to 0.91). Within the other four age and gender strata, the relationship was less consistent. CONCLUSION: Pain is associated with reduced physical activity in adolescents but this association varies according to gender, age, and the type of pain experienced.

Raman spectroscopic characterisation of resin-infiltrated hypomineralised enamel.

Raman spectroscopy was used to investigate how the effect of pre-treatment protocols, with combinations of hydrochloric acid (HCl), sodium hypochlorite (NaOCl) and hydrogen peroxide (H2O2), for molar-incisor hypo-mineralisation (MIH) altered the penetration depth of polymer infiltrants (ICON, DMG, Hamburg, Germany). Furthermore, the effect on the structure of the MIH portions of the teeth with treatment is examined using multivariate analysis of spectra. It was found that pre-treatment protocols improved penetration depths. The structure of the MIH portion post-treatment appeared much closer to that of normal enamel suggesting a diminution of protein in the MIH region with treatment.

Elemental and chemical characterization of dolphin enamel and dentine using X-ray and Raman microanalyzes (Cetacea: Delphinoidea and Inioidea).

Dolphins show increased tooth number and simplified tooth shape compared to most mammals, together with a simpler ultrastructural organization and less demanding biomechanical function. However, it is unknown if these factors are also reflected in the chemical composition of their teeth. Here, the bulk chemical composition and elemental distribution in enamel and dentine of extant dolphins were characterized and interpreted using X-ray and spectroscopy techniques. Teeth of 10 species of Delphinida were analyzed by WDX, EDX and Raman spectroscopy. For most of the species sampled, the mineral content was higher in enamel than in dentine, increasing from inner towards outer enamel. The transition from dentine to enamel was marked by an increase in concentration of the major components Ca and P, but also in Na and Cl. Mg decreased from dentine to enamel. Concentrations of Sr and F were often low and below detection limits, but F peaked at the outer enamel region for some species. Raman spectroscopy analyzes showed characteristics similar to carbonated hydroxyapatite, with the strongest peak for the phosphate PO4(3-) stretching mode at 960-961cm(-1). Dentine samples revealed a higher diversity of peaks representative of organic components and proteins than enamel. The similar distribution pattern and small variation in average concentration of major and minor elements in dentine and enamel of dolphins suggest that they are subject to strong physiological control. A clear trend of the elemental variations for all dolphin species sampled suggests that the general pattern of tooth chemistry is conserved among the Mammalia.

Ceramic implants (Y-TZP): are they a viable alternative to titanium implants for the support of overdentures? A randomized clinical trial.

OBJECTIVE: The objective of this study was to assess 1-year clinical success of one-piece zirconia implants compared with similar-design titanium implants, in the context of a novel protocol for implant distribution. MATERIALS AND METHODS: Twenty-four edentulous participants were randomly allocated to one-piece titanium or zirconia implant group. Each participant received four implants in the maxilla (mid-palatal and three anterior crestal implants) and three implants in the mandible (mid-symphyseal and two bilateral distal implants). Conventional loading protocol was followed. Marginal bone remodeling and clinical success of implants were evaluated. The data were statistically analyzed, and risk predictors for implant failures were evaluated. RESULTS: There was no significant difference in the survival rate between the two groups. In the mandible, the survival rate of titanium implants was 95.8% vs. 90.9% for the zirconia implants. The corresponding values in the maxilla were 71.9% and 55%, respectively. Three implants in the zirconia group fractured. Statistically significant less marginal bone loss was observed around titanium implants (0.18 mm) compared with the zirconia group (0.42 mm). The prediction model revealed a higher risk for implant failures in the maxilla (P < 0.0001). CONCLUSION: The outcome of this study indicates caution before recommendation can be made for the use of single-piece zirconia implants for overdenture support. Their use should be limited to cases with proven allergy to titanium. This is mainly due to the increased bone loss and higher fracture rate observed for zirconia implants. Future biomaterial research should focus on producing surface characteristics on zirconia implants with outcomes similar to those established for the optimum osseointegration of titanium implants.

Patients' perspectives on zirconia and titanium implants with a novel distribution supporting maxillary and mandibular overdentures: a qualitative study.

OBJECTIVES: This qualitative study explored the perceptions of edentulous patients regarding their rehabilitation with maxillary and mandibular implant-supported overdentures employing a protocol that featured novel implant sites and distribution. MATERIAL AND METHODS: In-depth semi-structured interviews were conducted with 16 participants who have taken part in a randomized controlled trial. Each received implant overdentures supported by either titanium or zirconia one-piece implants. Participants received four implants in the maxilla and three implants in the mandible. The implant distribution was: in the maxilla, a mid-palatal implant, and three anterior implants in the incisor and first premolar regions; in the mandible, a mid-symphseal implant, and bilateral distal implants in the first molar region. All interviews were conducted by a researcher not involved with the clinical aspect of the randomized controlled trial and were transcribed verbatim and analyzed using a thematic inductive analysis approach. RESULTS: The perceived advantages of the treatment were functional improvement and increased social confidence. Cost was a significant barrier for edentulous patients seeking implant treatment. Previous experience with complete dentures, age and length of treatment was further factors that influenced decisions regarding prosthodontic rehabilitation. The novel implant protocol was acceptable to patients. CONCLUSIONS: Implant overdentures improve the quality of life of edentulous patients. Acceptance of dental implants may be increased by mitigating the cost of treatment. The mid-palatal implant site may be a potential alternative to extensive surgical procedures during the prosthodontic rehabilitation of atrophic maxillary ridges. The mandibular design offers patients the advantages of a removable prosthesis with increased retention.