The World Federation of Chiropractic Global Patient Safety Task Force: a call to action

BACKGROUND

The Global Patient Safety Action Plan, an initiative of the World Health Organization (WHO), draws attention to patient safety as being an issue of utmost importance in healthcare. In response, the World Federation of Chiropractic (WFC) has established a Global Patient Safety Task Force to advance a patient safety culture across all facets of the chiropractic profession. This commentary aims to introduce principles and call upon the chiropractic profession to actively engage with the Global Patient Safety Action Plan beginning immediately and over the coming decade.

MAIN TEXT

This commentary addresses why the chiropractic profession should pay attention to the WHO Global Patient Safety Action Plan, and what actions the chiropractic profession should take to advance these objectives. Each strategic objective identified by WHO serves as a focal point for reflection and action. Objective 1 emphasizes the need to view each clinical interaction as a chance to improve patient safety through learning. Objective 2 urges the implementation of frameworks that dismantle systemic obstacles, minimizing human errors and strengthening patient safety procedures. Objective 3 supports the optimization of clinical process safety. Objective 4 recognizes the need for patient and family engagement. Objective 5 describes the need for integrated patient safety competencies in training programs. Objective 6 explains the need for foundational data infrastructure, ecosystem, and culture. Objective 7 emphasizes that patient safety is optimized when healthcare professionals cultivate synergy and partnerships.

CONCLUSIONS

The WFC Global Patient Safety Task Force provides a structured framework for aligning essential considerations for patient safety in chiropractic care with WHO strategic objectives. Embracing the prescribed action steps offers a roadmap for the chiropractic profession to nurture an inclusive and dedicated culture, placing patient safety at its core. This commentary advocates for a concerted effort within the chiropractic community to commit to and implement these principles for the collective advancement of patient safety.

Rehabilitation of back pain in the pediatric population: a mixed studies systematic review

BACKGROUND

A significant proportion of children and adolescents experience back pain. However, a comprehensive systematic review on the effectiveness of rehabilitation interventions is lacking.

OBJECTIVES

To evaluate benefits and harms of rehabilitation interventions for non-specific low back pain (LBP) or thoracic spine pain in the pediatric population.

METHODS

Seven bibliographic electronic databases were searched from inception to June 16, 2023. Moreover, reference lists of relevant studies and systematic reviews, three targeted websites, and the WHO International Clinical Trials Registry Platform were searched. Paired reviewers independently conducted screening, assessed risk of bias, and extracted data related to study characteristics, methodology, subjects, and results. Certainty of evidence was evaluated based on the GRADE approach.

RESULTS

We screened 8461 citations and 307 full-text articles. Ten quantitative studies (i.e., 8 RCTs, 2 non-randomized clinical trials) and one qualitative study were included. With very low to moderate certainty evidence, in adolescents with LBP, spinal manipulation (1-2 sessions/week over 12 weeks, 1 RCT) plus exercise may be associated with a greater likelihood of experiencing clinically important pain reduction versus exercise alone; and group-based exercise over 8 weeks (2 RCTs and 1 non-randomized trial) may reduce pain intensity. The qualitative study found information provided via education/advice and compliance of treatment were related to effective treatment. No economic studies or studies examining thoracic spine pain were identified.

CONCLUSIONS

Spinal manipulation and group-based exercise may be beneficial in reducing LBP intensity in adolescents. Education should be provided as part of a care program. The overall evidence is sparse. Methodologically rigorous studies are needed.

TRIAL REGISTRATION

CRD42019135009 (PROSPERO).

Contralateral Nodal Relapse in Well-lateralised Oral Cavity Cancers Treated Uniformly with Ipsilateral Surgery and Adjuvant Radiotherapy With or Without Concurrent Chemotherapy: a Retrospective Study

AIMS

To evaluate the incidence and pattern of contralateral nodal relapse (CLNR), contralateral nodal relapse-free survival (CLNRFS) and risk factors predicting CLNR in well-lateralised oral cavity cancers (OCC) treated with unilateral surgery and adjuvant ipsilateral radiotherapy with or without concurrent chemotherapy.

MATERIALS AND METHODS

Consecutive patients of well-lateralised OCC treated between 2012 and 2017 were included. The primary endpoint was incidence of CLNR and CLNRFS. Univariable and multivariable analyses were carried out to identify potential factors predicting CLNR.

RESULTS

Of the 208 eligible patients, 21 (10%) developed isolated CLNR at a median follow-up of 45 months. The incidence of CLNR was 21.3% in node-positive patients. CLNR was most common at level IB (61.9%) followed by level II. The 5-year CLNRFS and overall survival were 82.5% and 57.7%, respectively. Any positive ipsilateral lymph node (P = 0.001), two or more positive lymph nodes (P < 0.001), involvement of ipsilateral level IB (P = 0.002) or level II lymph node (P < 0.001), presence of extranodal extension (P < 0.001), lymphatic invasion (P = 0.015) and perineural invasion (P = 0.021) were significant factors for CLNR on univariable analysis. The presence of two or more positive lymph nodes (P < 0.001) was an independent prognostic factor for CLNR on multivariable analysis. CLNR increased significantly with each increasing lymph node number beyond two compared with node-negative patients.

CONCLUSION

The overall incidence of isolated CLNR is low in well-lateralised OCC. Patients with two or more positive lymph nodes have a higher risk of CLNR and may be considered for elective treatment of contralateral neck.

Use of Nanoindentation in Determination of Regional Biomechanical Properties of Rabbit Cornea After UVA Cross-Linking

Purpose

To evaluate the regional effects of different corneal cross-linking (CXL) protocols on corneal biomechanical properties.

Methods

The study involved both eyes of 50 rabbits, and the left eyes were randomized to the five intervention groups, which included the standard CXL group (SCXL), which was exposed to 3-mW/cm2 irradiation, and three accelerated CXL groups (ACXL1-3), which were exposed to ultraviolet-A at irradiations of 9 mW/cm2, 18 mW/cm2, and 30 mW/cm2, respectively, but with the same total dose (5.4 J/cm2). A control (CO) group was not exposed to ultraviolet-A. No surgery was done on the contralateral eyes. The corneas of each group were evaluated by the effective elastic modulus (Eeff) and the hydraulic conductivity (K) within a 7.5-mm radius using nanoindentation measurements.

Results

Compared with the CO group, Eeff (in regions with radii of 0-1.5 mm, 1.5-3.0 mm, and 3.0-4.5 mm) significantly increased by 309%, 276%, and 226%, respectively, with SCXL; by 222%, 209%, and 173%, respectively, with ACXL1; by 111%, 109%, and 94%, respectively, with ACXL2; and by 59%, 41%, and 37%, respectively, with ACXL3 (all P < 0.05). K was also significantly reduced by 84%, 81%, and 78%, respectively, with SCXL; by 75%, 74%, and 70%, respectively, with ACXL1; by 64%, 62%, and 61%, respectively, with ACXL2; and by 33%, 36%, and 32%, respectively, with ACXL3 (all P < 0.05). For the other regions(with radii between 4.5 and 7.5 mm), the SCXL and ACXL1 groups (but not the ACXL2 and ACXL3 groups) still showed significant changes in Eeff and K.

Conclusions

CXL had a significant effect on corneal biomechanics in both standard and accelerated procedures that may go beyond the irradiated area. The effect of CXL in stiffening the tissue and reducing permeability consistently decreased with reducing the irradiance duration.

Challenges in the Sustainability of Brachytherapy Service in Contemporary Radiotherapy

Brachytherapy has a long history of delivering a highly conformal radiation dose to the target volume with sparing of adjacent normal tissue and has an irreplaceable role in certain cancers, such as cervical and prostate cancers. There have been futile attempts to replace brachytherapy with other radiation techniques. Despite that there are multifaceted challenges in preserving this dying art, from establishment, to a trained workforce, to maintenance of the equipment and source replacement costs. Here we focus on the challenges to access brachytherapy, the availability and distribution of care across the globe and appropriate training leading to proper implementation of the procedure. Brachytherapy holds a significant place in the treatment armamentarium of most common cancers, such as cervical, prostate, head and neck and skin cancers. However, there is an uneven distribution of brachytherapy facilities, not only across the globe, but also at a national level, with a larger proportion of facilities concentrated in certain regions, more so in low and low-middle income countries. The regions with the highest incidence of cervical cancer have the least access to brachytherapy facilities. Attempts to bridge the gap are essential and should be focused on uniform distribution and access to care, improving training of the workforce through specialised training programmes, reducing the cost of care, planning to reduce the recurring cost, generating evidence and research guidelines, renewing interest in brachytherapy through rebranding, use of social media and building an attainable long-term roadmap.

Non-surgical organ preservation in laryngeal and hypopharyngeal cancers: an audit from the clinic

BACKGROUND

There is increasing concern regarding efficacy of organ preservation protocol in laryngeal and hypopharyngeal cancers.

METHOD

This study retrospectively assessed disease-related and functional outcomes of 191 patients with non-metastatic laryngeal or hypopharyngeal squamous cell carcinoma treated with curative intent (radiotherapy with or without chemotherapy).

RESULTS

Seventy-six patients (39.8 per cent) had a primary cancer in the larynx, and 115 patients (60.2 per cent) had a primary cancer in the hypopharynx. The median follow up was 39 months. The 3-year time to progression, overall survival, local control and laryngectomy free survival was 56.2 per cent, 76.3 per cent, 73.2 per cent and 67.2 per cent, respectively. At the time of analysis, 83 patients (43.5 per cent) were alive and disease free at their last follow up and did not require tube feeding or tracheostomy. The laryngo-oesophageal dysfunction-free survival was 61 per cent at 3 years.

CONCLUSION

Organ conservation protocols remain the standard of treatment in appropriately selected patients with laryngeal and hypopharyngeal cancers.

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.

Nondeterministic multiobjective optimization of 3D printed ceramic tissue scaffolds

Despite significant advances in the design optimization of bone scaffolds for enhancing their biomechanical properties, the functionality of these synthetic constructs remains suboptimal. One of the main challenges in the structural optimization of bone scaffolds is associated with the large uncertainties caused by the manufacturing process, such as variations in scaffolds' geometric features and constitutive material properties after fabrication. Unfortunately, such non-deterministic issues have not been considered in the existing optimization frameworks, thereby limiting their reliability. To address this challenge, a novel multiobjective robust optimization approach is proposed here such that the effects of uncertainties on the optimized design can be minimized. This study first conducted computational analyses of a parameterized ceramic scaffold model to determine its effective modulus, structural strength, and permeability. Then, surrogate models were constructed to formulate explicit mathematical relationships between the geometrical parameters (design variables) and mechanical and fluidic properties. The Non-Dominated Sorting Genetic Algorithm II (NSGA-II) was adopted to generate the robust Pareto solutions for an optimal set of trade-offs between the competing objective functions while ensuring the effects of the noise parameters to be minimal. Note that the nondeterministic optimization of tissue scaffold presented here is the first of its kind in open literature, which is expected to shed some light on this significant topic of scaffold design and additive manufacturing in a more realistic way.

On interaction between fatigue of reconstruction plate and time-dependent bone remodeling

BACKGROUND AND OBJECTIVE

The fibula free flap (FFF) has been extensively used to repair large segmental bone defects in the maxillofacial region. The reconstruction plate plays a key role in maintaining stability and load-sharing while the fibula unites with adjacent bone in the course of healing and remodeling. However, not all fibula flaps would fully unite, and fatigue of prosthetic devices has been recognized as one major concern for long-term load-bearing applications. This study aims to develop a numerical approach for predicting the fatigue life of the reconstruction plate by taking into account the effect of ongoing bone remodeling.

METHODS

The patient-specific mandible reconstruction with a prosthetic system is studied in this work. The 3D finite element model with heterogeneous material properties obtained from clinical computerized tomography (CT) data is developed for bone, and eXtended Finite Element Method (XFEM) is adopted for the fatigue analysis of the plate. During the remodeling process, the changing apparent density and Young's modulus of bone are simulated in a step-wise fashion on the basis of Wolff's law, which is correlated with the specific clinical follow-up. The maximum biting forces were considered as the driving force on the bone remodeling, which are measured clinically at different time points (4, 16 and 28 months) after reconstruction surgery.

RESULTS

Under various occlusal loadings, the interaction between fatigue crack growth and bone remodeling is investigated to gain new insights for the future design of prosthetic devices. The simulation results reveal that appropriate remodeling of grafted bone could extend the fatigue life of fixation plates in a positive way. On the other hand, the rising occlusal load associated with healing and remodeling could lead to fatigue fracture of fixation plate and potentially cause severe bone resorption.

CONCLUSION

This study proposes an effective approach for more realistically predicting fatigue life of prosthetic devices subject to a tissue remodeling condition in-silico. It is anticipated to provide a guideline for deriving an optimal design of patient-specific prosthetic devices to better ensure longevity.

Systematic review of response criteria and endpoints in autoimmune hepatitis by the International Autoimmune Hepatitis Group

BACKGROUND & AIMS

Autoimmune hepatitis (AIH) has been well characterised and codified through the development of diagnostic criteria. These criteria have been adapted and simplified and are widely used in clinical practice. However, there is a need to update and precisely define the criteria for both treatment response and treatment.

METHODS

A systematic review was performed and a modified Delphi consensus process was used to identify and redefine the response criteria in autoimmune hepatitis.

RESULTS

The consensus process initiated by the International Autoimmune Hepatitis Group proposes that the term 'complete biochemical response' defined as 'normalization of serum transaminases and IgG below the upper limit of normal' be adopted to include a time point at 6 months after initiation of treatment. An insufficient response by 6 months was a failure to meet the above definition. Non-response was defined as '<50% decrease of serum transaminases within 4 weeks after initiation of treatment'. Remission is defined as liver histology with a Hepatitis Activity Index <4/18. Intolerance to treatment was agreed to stand for 'any adverse event possibly related to treatment leading to potential drug discontinuation'.

CONCLUSIONS

These definitions provide a simple and reproducible framework to define treatment response and non-response, irrespective of the therapeutic intervention. A consensus on endpoints is urgently required to set a global standard for the reporting of study results and to enable inter-study comparisons. Future prospective database studies are needed to validate these endpoints.

LAY SUMMARY

Consensus among international experts on response criteria and endpoints in autoimmune hepatitis is lacking. A consensus on endpoints is urgently required to set a global standard for the reporting of study results and to enable the comparison of results between clinical trials. Therefore, the International Autoimmune Hepatitis Group (IAIHG) herein presents a statement on 5 agreed response criteria and endpoints: complete biochemical response, insufficient response, non-response, remission, and intolerance to treatment, which can be used to guide future reporting.

Student attitudes toward the International Clinical and Professional Chiropractic Education Position Statement and Evidence-based practice: a survey of UQTR chiropractic students

OBJECTIVE

The aim of this study is to describe the attitude of Université du Québec à Trois-Rivières (UQTR) chiropractic students toward the International Clinical and Professional Chiropractic Education Position Statement and evidence-based practice (EBP) beliefs.

METHODS

A cross-sectional survey was administered to all the UQTR chiropractic students. Using a five-point Likert scale, students were asked to rate their level of agreement with the position statement (10 items), EBP (2 items), interprofessional collaboration (2 items) and vitalistic philosophy (2 items).

RESULTS

Survey response rate was 71%. Students most frequently reported strong agreement with the position statement, EBP and interprofessional collaboration. They also most frequently disagreed with vitalistic philosophy. The attitude toward the position statement was positively correlated with the year of study in the program (r=0.10, p=0.019), EBP (r=0.56, p<0.001) and interprofessional collaboration (r=0.45, p <0.001).

CONCLUSIONS

UQTR chiropractic students demonstrate high levels of agreement with EBP and the Education Position Statement.

A211 INCIDENCE OF PRIMARY SCLEROSING CHOLANGITIS: A META-ANALYSIS OF POPULATION-BASED STUDIES

Background

Primary sclerosing cholangitis (PSC) is a chronic liver disease associated with significant morbidity, mortality and healthcare utilization. Understanding the incidence of PSC is important in defining the burden of disease and planning for allocation of healthcare resources.

Aims

To conduct a systematic review and meta-analysis of population-based studies of the incidence of PSC and to assess temporal trends of incidence overtime.

Methods

Medline and Embase (from inception to May 10, 2021) were systematically searched to identify studies via the following inclusion criteria: 1) original articles, 2) population-based study of defined geographic area, 3) reported the incidence of PSC or provided data to calculate the incidence of PSC. Studies that assessed specific populations (e.g., pediatric-only, IBD-only) or reported less than 1 year of data were excluded. Abstracts and full texts were reviewed for inclusion and data was extracted independently in duplicate by two individuals (JC, AM). Meta-analyses were performed to calculate overall and country-specific incidence rates (per 100,000 persons) with 95% confidence intervals (CI). Meta-regression calculated the Average Annual Percentage Change (AAPC) of PSC incidence rates overtime.

Results

The initial search returned 3,958 abstracts. After duplicates were removed, abstracts (3,443) were screened, and full texts were reviewed (317), 17 studies met the criteria for inclusion and underwent data extraction. Meta-analysis included 6 studies with annual data contributing to the calculation of AAPC. Studies originated from 10 countries from North America, Europe, and Oceania; however, no population-based studies were published in Asia, Africa, or Latin America (Figure 1). Overall, the incidence rates of PSC was 0.82 per 100,000 (95% CI: 0.62, 1.02) (Figure 1). Incidence rates of PSC were significantly increasing overtime (AAPC: 4.56%; 95% CI: 0.45, 8.68).

Conclusions

The incidence of PSC is low at 0.82 per 100,000 but has been significantly increasing over time. Future studies on the incidence of PSC should be directed at Asia, Africa of Latin America to assess the global epidemiology of PSC.

Figure 1: Pooled incidence rate estimates of PSC per 100,000 person-years at risk.

Funding Agencies

None

A202 IMPACT OF THE COVID-19 PANDEMIC ON THE EPIDEMIOLOGY OF ALCOHOL-RELATED HEPATITIS

Background

Alcohol-related hepatitis (AH) is the most severe form of alcohol-related liver disease, with rising incidence. Stay-at-home orders for the COVID-19 pandemic were associated with increased alcohol consumption. Online sales reported a 262% increase from March 2019 to 2020.

Aims

The purpose of this study was to track the epidemiology of hospitalizations for AH by sex before and after the COVID-19 pandemic. We hypothesized that AH would be more severe in females and younger individuals during the pandemic.

Methods

Using the Discharge Abstract Database, we identified all hospitalizations in Alberta with international classification of disease-10 codes for AH between March 2018 and September 2020. We merged this dataset with provincial laboratory data to identify all inpatient lab values. We calculated Model for End-Stage Liver Disease (MELD) and Maddrey scores and validated a laboratory-based algorithm for AH. Severe AH was defined as Maddrey score > 32. Onset of the pandemic was defined as March 2020. Stratified by pandemic onset, descriptive statistics were done with Chi-squared and Kruskal Wallis tests. Inpatient mortality was assessed as a primary outcome. Binomial regression was used to assess changes in frequency of admission for AH with the denominator as all cirrhosis-related admissions over the same time-period.

Results

We identified 991 hospitalizations for AH prior to the pandemic (n=381, 38.5% female) and 417 during the pandemic (n=144, 34.5% female). Hospitalizations for AH significantly increased during the pandemic (p = 0.04) (Figure 1). Median Maddrey score for females (30.5) before the pandemic was significantly higher than for males (22.9), p < 0.01. During the pandemic, median Maddrey for females (28.7) was higher than males 21.4, p = 0.07. Median age at admission was significantly lower for both males and females during the pandemic (age 44 and 41, respectively) as compared to prior (age 47 and 45, respectively) p < 0.05. There was no significant difference in MELD between sexes before (13.5 for females, 14.0 for males, p = 0.15) and during the pandemic (13.3 for females, 13.0 for males, p = 0.75). Additionally, there was no significant difference in mortality between sexes before (10.4% in females, 11.5% in males, p = 0.22) and after the pandemic (9.2% in females, 9.9% in males, p = 0.67).

Conclusions

Hospitalizations for AH rose during the pandemic and occurred at younger ages. There was no significant difference in disease severity or mortality before and during the pandemic. Overall, females have more severe AH than males. Public health efforts should continue to be made to educate about the harms of alcohol excess and offer community support. Future studies will expand the trend through multiple pandemic waves.

Funding Agencies

None

Post-cricoid and Upper Oesophagus Cancers Treated with Organ Preservation Using Intensity-modulated Image-guided Radiotherapy: a Phase II Prospective Study of Outcomes, Toxicity and Quality of Life

AIMS

To prospectively examine the outcomes, toxicity and quality of life (QoL) of patients with post-cricoid and upper oesophagus (PCUE) cancers treated with an organ-preservation approach of (chemo)-radiotherapy using intensity-modulated image-guided radiotherapy (IM-IGRT).

MATERIALS AND METHODS

This phase II prospective study was conducted at a tertiary cancer centre from February 2017 to January 2020. Forty patients with squamous cell carcinoma of PCUE of stage T1-3, N0-2, M0 were accrued. Gross exolaryngeal extension/dysfunctional larynx were major exclusion criteria. Patients received 63-66 Gy in once-daily fractions using volumetric modulated arc therapy with daily IGRT. Outcome measures included disease-related outcomes, patterns of failure, Radiation Therapy Oncology Group toxicities, feeding tube dependency and QoL.

RESULTS

The median follow-up was 22 months. Twenty-six (87.5%) patients had locoregionally advanced disease and 34 (85%) patients received (chemo)-radiotherapy. A complete response was observed in 26 (65%) patients. The 2-year locoregional control, event-free survival and cause-specific survival were 59.6%, 40.2% and 44.8%, respectively. The volume of primary tumour (GTVPvol) exceeding 28 cm³ had inferior overall survival (P = 0.005) on univariate analysis. Multivariable analysis showed GTVPvol and positron emission tomography-computed tomography maximum standardised uptake value to be independently predictive for event-free and overall survival. A feeding tube requirement at presentation was seen in 11 (27.5%) patients, whereas long-term feeding tube dependency at 6 months was seen in 10 (37%) patients. For QoL, a statistical improvement in pain, appetite loss and swallowing was observed over time.

CONCLUSION

Although the outcomes of PCUE cancers remain dismal, the use of state of the art diagnostic modalities, careful case selection and modern radiotherapy techniques improved outcomes as compared with before in this exclusive analysis of PCUE cancers.

Mechanical failure of posterior teeth due to caries and occlusal wear- A modelling study

OBJECTIVES

The purpose of the present work is to explore the effect of occlusal wear and different types and degrees of caries on the mechanical performance and structural integrity of posterior teeth.

METHODS

Three-dimensional (3D) computational models with different combinations of caries parameters (caries location, caries size and caries induced pulp shrinkage) and occlusal wear factors (enamel thickness, marginal ridge height and cuspal slope) were developed and analyzed using the extended finite element method (XFEM) to identify the stress distribution, crack initiation load and ultimate fracture load values. The effect of a non-drilling conservative treatment using resin infiltration on the recovery of mechanical properties of carious molar teeth was also investigated.

RESULTS

Presence of fissural caries, worn proximal marginal ridge and decreased enamel thickness due to occlusal wear, imparted a significant negative effect on the crack initiation load value of the lower molar models. Accordingly, models with intact and strong proximal marginal ridge, generally exhibited higher crack initiation loading, regardless of caries size and location. Presence of fissure caries drastically decreased (55%-70%) the crack initiation load compared to sound teeth. The depth of the fissural lesion and the presence of proximal caries did not have a major effect on crack initiation load values. However, increasing the caries size resulted in lower final fracture load values in most of the cases. Accordingly, the groups with combined and connected large fissural and proximal lesions experienced the largest drop in the fracture load values compared to sound tooth models. The worst condition consisted of two connected large proximal and fissural caries with no proximal marginal ridge, in which the fracture load dramatically decreased to only 25% of that for sound teeth with intact marginal ridge. On the other hand, decreased cuspal slope due to occlusal wear and shrinkage of the pulp due to caries appeared to have a protective role and a direct relation with the fracture resistance of the tooth. Following the application of resin infiltration on the carious models, the crack initiation load and the fracture load could recover up to 75% and 90% of the values for the corresponding sound tooth models, respectively.

SIGNIFICANCE

Presence of fissural caries, if not treated (either with remineralization, resin infiltration or restoration), can be a major risk factor in the initiation of tooth fracture. When combined with decreased enamel thickness and loss of proximal marginal ridge due to mechanical or chemical wear, the weakening effect of the caries will be amplified specially in teeth with steep cuspal slopes. The application of a conservative treatment with resin infiltration can be an effective approach in prevention of further mechanical failure of demineralized enamel. The findings of this study emphasize the importance of early interventions in the management of caries for the prevention of future cuspal or tooth fracture especially in subjects with higher risk factors for tooth fracture such as caries, wear and bruxism.

Chiropractic student diagnosis and management of headache disorders: A survey examining self-perceived preparedness and clinical proficiency

OBJECTIVE

To explore the self-perceived preparedness and clinical proficiency in headache diagnosis and management of Australian chiropractic students in senior years of study.

METHODS

Australian chiropractic students in the 4th (n = 134) and 5th year (n = 122) of 2 chiropractic university programs were invited to participate in an online cross-sectional survey. Descriptive analyses were conducted for all variables. Post hoc analyses were performed using simple linear regression to evaluate the relationship between self-perceived preparedness and correctness of headache diagnosis and management scores.

RESULTS

Australian chiropractic students in senior years demonstrated moderate overall levels of self-perceived preparedness and proficiency in their ability to diagnose and manage headache disorders. Final-year students had a slightly higher self-perceived preparedness and proficiency in headache diagnosis and management compared to those students in the 4th year of study. There was no relationship between self-perceived preparedness and correctness of headache diagnosis and management for either 4th- or 5th-year chiropractic students.

CONCLUSION

Our findings suggest that there may be gaps in graduate chiropractic student confidence and proficiency in headache diagnosis and management. These findings call for further research to explore graduate chiropractic student preparedness and proficiency in the diagnosis and management of headache disorders.

Willingness to Participate in Health Research Among Community-Dwelling Middle-Aged and Older Adults: Does Race/Ethnicity Matter?

INTRODUCTION

Older adults, including racial and ethnic minorities, are underrepresented in research. As the US population ages, the number of older racial and ethnic minority individuals will increase. Including these individuals in research is an important step towards reducing health disparities.

METHODS

We used data from HealthStreet, a University of Florida community engagement program which uses community health workers to assess the health of the community, to assess willingness to participate in different types of health research by race/ethnicity. Descriptive statistics and logistic regression models were used to assess willingness to participate among adults aged 50 and older, by race/ethnicity (n = 4694).

RESULTS

Our sample was 42.0% non-Hispanic White, 52.8% non-Hispanic Black, and 5.2% Hispanic. Non-Hispanic White participants reported more past research participation than non-Hispanic Black and Hispanic participants (28.7% vs. 19.0% and 19.2%, respectively). Compared with non-Hispanic White participants, non-Hispanic Black participants were less willing to participate in most types of studies, while Hispanic participants were less willing to participate in studies that might be seen as invasive (required blood sample, genetic sample, or participants to take medicine, or use of medical equipment).

CONCLUSIONS

Our study provides investigators with a general profile of research preferences by race/ethnicity; compared with non-Hispanic White individuals, non-Hispanic Black individuals are less willing to participate in most studies, while Hispanic individuals are less willing to participate in studies that may be seen as invasive or demanding. It is imperative to include diverse older adults in health research. By tailoring research based on preferences we can improve recruitment in underrepresented populations.

A210 DECLINE IN HEPATITIS B QUANTITATIVE SURFACE ANTIGEN LEVELS IN CHRONIC HEPATITIS B PATIENTS ON TREATMENT WITH NUCLEOS(T)IDE ANALOGUES

Background

The Hepatitis B virus (HBV) affects over 250 million people worldwide and can lead to cirrhosis and hepatocellular carcinoma. HBV surface antigen (HBsAg) quantification is increasingly used to predict disease activity and treatment response. As there is no virologic cure, clinicians are seeking a “functional cure”, or HBsAg loss, as a guide to safely stopping nucleos(t)ide analogue therapy. Tenofovir Disoproxil Fumarate (TDF) and Entecavir (ETV) are first line therapy but require prolonged treatment to achieve HBsAg clearance.

Aims

To assess the association between nucleos(t)ide therapy and decline in quantitative HBsAg (qHBsAg) in patients with HBV from Calgary, Alberta.

Methods

A retrospective review of adult patients with chronic HBV, followed at the University of Calgary Liver Clinic, was conducted between January 2012 and October 2020. Patients were excluded if treatment was discontinued or changed, only had a single qHBsAg measurement, or were co-infected with hepatitis C virus, hepatitis delta virus, or HIV. Patients were stratified according to therapy with TDF, ETV, or no treatment. To identify associations between mean changes in qHBsAg by medication exposure, one-way ANOVAs and t-tests were performed. Results were reported as means and 95% confidence intervals (CI). The median time from initial qHBsAg to most-recent was calculated.

Results

187 patients were included in the final analysis (Table 1). 77 were excluded for being on more than one medication over the study period, 10 were excluded due to discontinuation of treatment, and 195 were excluded for single qHBsAg measurements. The mean qHBsAg decline was -750.04 IU/mL (95% CI -1311.58, -188.50) in the TDF group (n=45) and -309.20 IU/mL (95% CI -600.90, -17.50) in the ETV group (n=35) (p=0.20). In the no treatment group (n=107), the mean qHBsAg increased by 711.29 IU/mL (95% CI -600.78, 2023.80)(Figure 1). The median time from initial qHBsAg to most-recent was 980 days.

Conclusions

Quantitative HBsAg levels declined in patients on TDF and ETV, but increased in untreated patients. Although HBsAg levels showed a trend for greater decline in TDF-treated patients, results failed to reach statistical significance, and may be affected by overall treatment duration. Future studies will explore medication use as a time-varying covariate to identify how change in treatment influences changes in HBsAg over time.

Funding Agencies

None

The global summit on the efficacy and effectiveness of spinal manipulative therapy for the prevention and treatment of non-musculoskeletal disorders: a systematic review of the literature

Background

A small proportion of chiropractors, osteopaths, and other manual medicine providers use spinal manipulative therapy (SMT) to manage non-musculoskeletal disorders. However, the efficacy and effectiveness of these interventions to prevent or treat non-musculoskeletal disorders remain controversial.

Objectives

We convened a Global Summit of international scientists to conduct a systematic review of the literature to determine the efficacy and effectiveness of SMT for the primary, secondary and tertiary prevention of non-musculoskeletal disorders.

Global summit

The Global Summit took place on September 14–15, 2019 in Toronto, Canada. It was attended by 50 researchers from 8 countries and 28 observers from 18 chiropractic organizations. At the summit, participants critically appraised the literature and synthesized the evidence.

Systematic review of the literature

We searched MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, the Cumulative Index to Nursing and Allied Health, and the Index to Chiropractic Literature from inception to May 15, 2019 using subject headings specific to each database and free text words relevant to manipulation/manual therapy, effectiveness, prevention, treatment, and non-musculoskeletal disorders. Eligible for review were randomized controlled trials published in English. The methodological quality of eligible studies was assessed independently by reviewers using the Scottish Intercollegiate Guidelines Network (SIGN) criteria for randomized controlled trials. We synthesized the evidence from articles with high or acceptable methodological quality according to the Synthesis without Meta-Analysis (SWiM) Guideline. The final risk of bias and evidence tables were reviewed by researchers who attended the Global Summit and 75% (38/50) had to approve the content to reach consensus.

Results

We retrieved 4997 citations, removed 1123 duplicates and screened 3874 citations. Of those, the eligibility of 32 articles was evaluated at the Global Summit and 16 articles were included in our systematic review. Our synthesis included six randomized controlled trials with acceptable or high methodological quality (reported in seven articles). These trials investigated the efficacy or effectiveness of SMT for the management of infantile colic, childhood asthma, hypertension, primary dysmenorrhea, and migraine. None of the trials evaluated the effectiveness of SMT in preventing the occurrence of non-musculoskeletal disorders. Consensus was reached on the content of all risk of bias and evidence tables. All randomized controlled trials with high or acceptable quality found that SMT was not superior to sham interventions for the treatment of these non-musculoskeletal disorders. Six of 50 participants (12%) in the Global Summit did not approve the final report.

Conclusion

Our systematic review included six randomized clinical trials (534 participants) of acceptable or high quality investigating the efficacy or effectiveness of SMT for the treatment of non-musculoskeletal disorders. We found no evidence of an effect of SMT for the management of non-musculoskeletal disorders including infantile colic, childhood asthma, hypertension, primary dysmenorrhea, and migraine. This finding challenges the validity of the theory that treating spinal dysfunctions with SMT has a physiological effect on organs and their function. Governments, payers, regulators, educators, and clinicians should consider this evidence when developing policies about the use and reimbursement of SMT for non-musculoskeletal disorders.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12998-021-00362-9.

Sports chiropractors in Australia: a cross-sectional survey

BACKGROUND

Whilst half of all Australian chiropractors report often treating athletes, there is insufficient evidence to characterise the sports chiropractor in Australia.

OBJECTIVE

To perform a workforce survey of Sports Chiropractic Australia (SCA) members.

METHODS

A 74-item web-based questionnaire collected information about practitioner and practice characteristics. Descriptive statistics summarised practitioner and patient characteristics, caseload and management approaches.

RESULTS

SCA members were predominantly male (74%) with 11.3 (±8.4) years of clinical experience. Amateur or semi-professional sportspeople comprised 67% of SCA members' caseload. Athletes were most likely to present with a lower limb musculoskeletal condition (44%), followed by low back pain (34%). Nearly half (43%) of musculoskeletal conditions were co-managed with another healthcare practitioner.

CONCLUSIONS

SCA members provided care for people of all sporting abilities, ranging from recreational to elite athletes, but most typically at the non-elite level. SCA members almost exclusively treat musculoskeletal conditions and apply various modalities in the management of athletes and sportspeople.

Rehabilitative management of back pain in children: protocol for a mixed studies systematic review

INTRODUCTION

Little is known about effective, efficient and acceptable management of back pain in children. A comprehensive and updated evidence synthesis can help to inform clinical practice.

OBJECTIVE

To inform clinical practice, we aim to conduct a systematic review of the literature and synthesise the evidence regarding effective, cost-effective and safe rehabilitation interventions for children with back pain to improve their functioning and other health outcomes.

METHODS AND ANALYSIS

We will search MEDLINE, Embase, PsycINFO, CINAHL, the Index to Chiropractic Literature, the Cochrane Controlled Register of Trials and EconLit for primary studies published from inception in all languages. We will include quantitative studies (randomised controlled trials, cohort and case-control studies), qualitative studies, mixed-methods studies and full economic evaluations. To augment our search of the bibliographic electronic databases, we will search reference lists of included studies and relevant systematic reviews, the WHO International Clinical Trials Registry Platform and consult with content experts. We will assess the risk of bias using appropriate critical appraisal tools. We will extract data about study and participant characteristics, intervention type and comparators, context and setting, outcomes, themes and methodological quality assessment. We will use a sequential approach at the review level to integrate data from the quantitative, qualitative and economic evidence syntheses.

ETHICS AND DISSEMINATION

Ethics approval is not required. We will disseminate findings through activities, including (1) presentations in national and international conferences; (2) meetings with national and international decision makers; (3) publications in peer-reviewed journals and (4) posts on organisational websites and social media.

PROSPERO REGISTRATION NUMBER

CRD42019135009.

Characterization of Enamel and Dentine about a White Spot Lesion: Mechanical Properties, Mineral Density, Microstructure and Molecular Composition

The study focuses on in vitro tracing of some fundamental changes that emerge in teeth at the initial stage of caries development using multiple approaches. The research was conducted on a mostly sound maxillary molar tooth but with a clearly visible natural proximal white spot lesion (WSL). Values of mineral density, reduced Young's modulus, indentation hardness and creep as well as the molecular composition and surface microstructure of the WSL and bordering dentine area were studied. The results obtained were compared to those of sound enamel and dentine on the same tooth. A decrease of mechanical properties and mineral density both for the WSL and bordering dentine was detected in comparison to the sound counterparts, as well as increase of creep for the enamel WSL. Differences in molecular composition and surface microstructure (including the indenter impressions) were found and described. WSL induces a serious change in the state of not only the visually affected enamel but also surrounding visually intact enamel and dentine in its vicinity. The results provide the basis for future studies of efficacy of minimal invasive treatments of caries.

A62 CANADIAN POPULATION-BASED EVALUATION OF THE NATURAL HISTORY OF PRIMARY BILIARY CHOLANGITIS OVER THE LAST DECADE

Background

Few studies have evaluated the epidemiology of primary biliary cirrhosis (PBC) in North America. Ursodeoxycholic acid (URSO) improves outcomes amongst PBC patients.

Aims

Therefore, we undertook this study to determine the epidemiology of PBC in Canada, and impact of URSO on clinical outcomes, two decades after URSO approval in North America.

Methods

We used our previously validated coding algorithm to identify PBC patients in population based administrative databases in the Calgary Health Zone (population ~1.5 million) from 2005–2015. Multiple sources of data including inpatient, ambulatory, physician billing, laboratory, and pharmaceutical were linked. Annual prevalence and incidence were estimated using Poisson regression. Age/sex adjusted rate ratios were calculated. We used Cox regression models to estimate: all-cause mortality, liver transplant and decompensated cirrhosis free survival. In our models, we adjusted for demographic and clinical variables including response to URSO.

Results

During the study period over 11 years, the overall annual age/sex adjusted PBC incidence was 29.5 cases per million (48.3 and 9.9 per million for women and men, respectively). The highest incidence rate was observed among women aged 60–79 (90.9 per million) with an incidence rate ratio of 10.4 (95%: 6.83–15.9) compared to those aged 20–39. While incidence rate remained stable, prevalence rate increased significantly from 242 to 343 cases/ million, between 2005 and 2015 (P&lt;0.01). Prevalence rate was highest at 965 cases/ million amongst women aged 60–79. We identified 299 incident PBC cases with a median follow up of 5.1 years (IQR 2.9–8.3). 87 (29.1%) of these incident cases developed decompensated cirrhosis or HCC, 10 patients (3.4%) underwent liver transplantation, and 44 (14.7%) patients died. The annual mortality rate was 2.9% (95%CI: 2.1- 3.8) compared to 3.4% (2.3–4.9%) a decade ago (P=0.04). The estimated 5-year survival rate was 87.6% (82.6- 91.3). Standardized mortality rate was 3.2 (95%CI: 2.2–4.1). Overall, 25% of our incident cohort were not prescribed URSO. Patients not prescribed URSO were more likely to be male, older age, have normal ALP and had decompensated cirrhosis at diagnosis (P&lt;0.01 for all). Among those who used URSO, response rate was 86%. Response to URSO was an independent predictor of reduced risk of decompensated cirrhosis and liver transplant, and higher survival (aHR: 0.46, 0.29–0.74).

Conclusions

PBC prevalence is increasing in this North American population. While mortality rate decreases in our PBC cohort, survival was suboptimal compared to the general population, mainly due to late presentation at diagnosis. Therefore, better surveillance and early detection of possible PBC patients in the primary care setting are essential to improve PBC outcomes.

Funding Agencies

None

A187 CHOLESTATIC LIVER DISEASE AND BRAIN DYSFUNCTION: ROLE OF THE ARYL HYDROCARBON RECEPTOR

Background

Cholestatic liver disease is associated with immune-mediated inflammatory liver injury. This disorder is also associated with brain dysfunction and behavioural changes, notably fatigue, depression and social withdrawal. The mechanisms leading to these central nervous system abnormalities are unknown, however, they are associated with neuroinflammation. Microglia and astrocytes are two glial populations that play key roles in neuroinflammation. Activated glia display morphological changes, secrete cytokines, and mediate electrophysiological changes, altering the normal functioning of the brain. The aryl hydrocarbon receptor (AhR) is a transcription factor involved in the immune response. AhR is present on glia and its’ activation has been shown to reduce neuroinflammation. The role of the AhR in cholestatic liver disease has yet to be examined.

Aims

To study the function of the AhR in a model of cholestic liver disease. We will test the hypothesis that activation of AhR in the brain will reduce neuroinflammation and behavioral deficits observed in cholestatic mice.

Methods

Male C57Bl/6J mice had cholestasis induced by bile duct ligation (BDL); comparisons were made to sham-operated controls. Mice were tested for social interaction with a 4-week old juvenile in their home cage and the number of social interaction attempts quantified. Next, mice were euthanized, brains were removed and processed for immunohistochemistry. Brain sections were stained for markers of microglia (IBA-1) and astrocytes (GFAP). Microglia were counted and astrocyte activation was qualitatively assessed. PCR was used to quantify gene expression of AhR and its downstream gene targets (eg. CYP1A1) in mice that recived treatment with beta-napthoflavone (BNF), an AhR agonist, or in vehicle treated controls.

Results

BDL mice made significantly fewer attempts to interact with the juvenile as compared to controls (P&lt;0.05). We also observed a significant increase in IBA-1 immunoreactive cell numbers in both the CA1 region of the hippocampus and the hypothalamic paraventricular nucleus (PVN, P&lt;0.05). BDL mice also displayed marked increases in GFAP+ staining in the PVN, but not the CA1, in contrast to sham controls. Lastly, we found that BNF significantly upregulated CYP1A1 (P&lt;0.05) in the liver and prefrontal cortex of mice. We are currently examining whether BNF can reduce neuroinflammation and improve decreased social interaction in cholestatic mice.

Conclusions

Cholestatic liver damage was associated with impaired social behavior. Further, glial activation, an indicator of neuroinflammation was increased in components of the limbic system associated with the response to stress, learning, and memory. Future experiments will address whether activation of the AhR will ameliorate neuroinflammation and behavioral changes observed in mice with cholestatic liver injury.

Funding Agencies

CCC, CIHR

The prevalence and determinants of physical activity promotion by Australian chiropractors: A cross sectional study

BACKGROUND

Approximately one in four adults do not meet the World Health Organisation physical activity recommendations. While health promotion (i.e., physical activity) is common within chiropractic settings, little is known about chiropractors discussing this public health issue with their patients. The aim of our study is to examine the prevalence and characteristics of Australian chiropractors who frequently discuss patient physical activity.

METHODS

A national cross-sectional survey of chiropractors focusing upon practitioner characteristics, practice settings and clinical management characteristics. Regression analyses were conducted on 1924 survey respondents to identify factors associated with practitioners who frequently discuss physical activity with patients.

RESULTS

Eighty-five percent of Australian chiropractors reported 'often' discussing physical activity as part of their patient management. The strongest factors associated with chiropractors who frequently discuss physical activity obtained from the multivariate analysis include: often discussing occupational health and safety (odds ratio [OR] = 6.10; 95%CI: 3.88, 9.59), often discussing diet/nutrition (OR = 4.56; 95%CI: 3.12, 6.66), often discussing smoking/drugs/alcohol (OR = 4.41; 95%CI: 2.06, 9.40), often use of specific exercise therapy/rehabilitation/injury taping (OR = 3.76; 95%CI: 2.62, 5.39) and often caring for athletes or sports people (OR = 2.18; 95%CI: 1.56, 3.06) within their practice setting.

CONCLUSION

Discussing physical activity is a frequent feature of patient management among most chiropractors in Australia. The association between these practitioners and discussion of other costly public health burdens could suggest chiropractors have a valuable role to play in chronic disease prevention. Given the growing need for practitioner-led promotion of patient physical activity further research examination of the role and contribution of chiropractors in promoting this important public health topic among patients and communities is needed.

Expectations influence treatment outcomes in patients with low back pain. A secondary analysis of data from a randomized clinical trial

Background

Low back pain (LBP) is a global public health challenge, which causes high healthcare costs and the highest burden on society in terms of years lived with disability. While patients’ expectations for improvement may have effects on LBP treatment outcomes, it remains unclear if psychological profiles modify this relationship. Therefore, the objectives of this study were to investigate if (a) patients’ expectations predicted short‐term outcome, and (b) psychological profile, pain intensity and self‐rated health modified the relationship between expectations and outcome.

Methods

Data were collected between April 2012 and January 2016 during the inclusion into a randomized controlled trial. Potentially eligible participants were identified through 40 chiropractic clinics located across Sweden. Patients’ expectations, psychological profile, pain intensity, activity limitation and self‐rated health were collected from patients with recurrent persistent LBP during their first chiropractic visit (n = 593). Subjective improvement was measured at the fourth visit.

Results

Patients with a high expectation of improvement had 58% higher risk to report an improvement at the fourth visit (RR = 1.58, 95% CI: 1.28, 1.95). Controlling for potential confounders only slightly decreased the strength of this association (RR = 1.49, 95% CI: 1.20, 1.86). Baseline pain intensity, psychological profile and self‐rated health did not modify the effect of expectation on outcome.

Conclusions

Baseline patients’ expectations play an important role when predicting LBP treatment outcomes. Clinicians should consider and address patients’ expectations at the first visit to best inform prognosis.

Significance

This study confirms the importance of patients’ expectations in a clinical setting. Patients’ expectations predict the short‐term outcome of chiropractic care for LBP. Pain intensity, psychological profile and self‐rated health did not modify this relationship.

The profile of chiropractors managing patients with low back-related leg pain: analyses of 1907 chiropractors from the ACORN practice-based research network

Background

Approximately 60% of people with low back pain also have associated leg pain symptoms. Guidelines for low back pain recommend non-pharmacological approaches, including spinal manipulation - a therapy provided by chiropractors. However, limited empirical data has examined the characteristics of chiropractors managing patients with low back-related leg pain (LBRLP). Our objective is to describe the prevalence, profile and practice characteristics of Australian chiropractors who often treat LBRLP, compared to those who do not often treat LBRLP.

Methods

This is a cross-sectional analysis of a nationally representative sample from the Australian Chiropractic Research Network (ACORN). This study investigated the demographic and practice characteristics as well as clinical management of chiropractors who ‘often’ treated patients with LBRLP compared to those who treated LBRLP ‘never/rarely/sometimes’. Multiple logistic regression models identified independent factors associated with chiropractors who ‘often’ treated patients with LBRLP.

Results

A total of 1907 chiropractors reported treating patients experiencing LBRLP, with 80.9% of them ‘often’ treating LBRLP. Chiropractors who ‘often’ treated LBRLP were more likely to manage patients with multi-site pain including axial low back pain (OR = 21.1), referred/radicular neck pain (OR = 10.8) and referred/radicular thoracic pain (OR = 3.1). While no specific management strategies were identified, chiropractors who ‘often’ treated LBRLP were more likely to discuss medication (OR = 1.8), manage migraine (OR = 1.7) and degenerative spine conditions (OR = 1.5), and treat women during pregnancy (OR = 1.6) and people with work-related injuries (OR = 1.5), compared to those not treating LBRLP frequently.

Conclusions

Australian chiropractors frequently manage LBRLP, although the nature of specific management approaches for this condition remains unclear. Further research on the management of LBRLP can better inform policy makers and educators interested in upskilling chiropractors to deliver safe and effective treatment of LBRLP.

Characteristics of chiropractors who manage people aged 65 and older: A nationally representative sample of 1903 chiropractors

OBJECTIVE

To examine the prevalence and profile of chiropractors who frequently manage people aged 65 years and older.

METHODS

A national cross-sectional survey collected practitioner characteristics, practice settings and clinical management characteristics. Multiple logistic regression was conducted on 1903 chiropractors to determine the factors associated with the frequent treatment of people 65 years and older.

RESULTS

In total, 73.5% of participants report "often" treating those aged 65 years and older. These chiropractors were associated with treating degenerative spine conditions (OR [odds ratio] 2.25; 95% [confidence interval] CI 1.72-2.94), working in a non-urban area (OR 1.85; 95% CI 1.35-2.54), treating low back pain (referred/radicular) (OR 1.74; 95% CI 1.26-2.40) and lower limb musculoskeletal disorders (OR 1.50; 95% CI 1.15-1.96).

CONCLUSIONS

The majority of chiropractors report often providing treatment to older people. Our findings call for more research to better understand older patient complaints that are common to chiropractic practice and the care provided by chiropractors for this patient group.

Modelling of stress distribution and fracture in dental occlusal fissures

The aim of this study was to investigate the fracture behaviour of fissural dental enamel under simulated occlusal load in relation to various interacting factors including fissure morphology, cuspal angle and the underlying material properties of enamel. Extended finite element method (XFEM) was adopted here to analyse the fracture load and crack length in tooth models with different cusp angles (ranging from 50° to 70° in 2.5° intervals), fissural morphologies (namely U shape, V shape, IK shape, I shape and Inverted-Y shape) and enamel material properties (constant versus graded). The analysis results showed that fissures with larger curved morphology, such as U shape and IK shape, exhibit higher resistance to fracture under simulated occlusal load irrespective of cusp angle and enamel properties. Increased cusp angle (i.e. lower cusp steepness), also significantly enhanced the fracture resistance of fissural enamel, particularly for the IK and Inverted-Y shape fissures. Overall, the outcomes of this study explain how the interplay of compositional and structural features of enamel in the fissural area contribute to the resistance of the human tooth against masticatory forces. These findings may provide significant indicators for clinicians and technicians in designing/fabricating extra-coronal dental restorations and correcting the cuspal inclinations and contacts during clinical occlusal adjustment.

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.

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.

Biomechanical Analysis of the Canine Tuberculum Dentale

We evaluate the structural significance of the development of a canine tuberculum dentale by means of three-dimensional finite element analysis. Using a scanned human permanent canine, we construct a computer generated canine, together with alveolar bone and periodontal ligament onto which we morph two cingulum shapes, namely a flat palatal surface and a stylised tuberculum dentale. We then subject the three shapes (flat, normal cingulum, and pronounced tuberculum dentale) to a normal occlusal force and we record principal and von Mises stresses in the crowns. Our results show that stresses are concentrated at the cingulum and in the approximal areas, and that these do not differ between the three forms. We conclude that the development of a tuberculum dentale does not confer biomechanical advantage to the human canine.

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.

Synthesis of stabilized hydroxyapatite nanosuspensions for enamel caries remineralization

BACKGROUND

The aim of this study was to develop and evaluate a method for synthesizing a stable suspension of hydroxyapatite nanoparticles and to test its efficacy for remineralizing carious enamel lesions.

METHODS

Hydroxyapatite (HA) particles were synthesized using wet chemistry. Synthesized particles were introduced into a high-pressure homogenizer (5-10 homogenization passes at 15 000 psi) in the presence of different stabilizers. Size and distribution of the resultant particles were determined using dynamic light scattering (DLS). The morphology and composition of the nanoparticles were determined using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Subsequently, artificial lesions were treated with HA nanosuspension plus artificial saliva or a fluoride-containing artificial saliva only. Visual analysis and quantification of the lesion mineral density before and after remineralization were performed using microcomputed tomography.

RESULTS

DLS and SEM results confirmed the formation of nonagglomerated HA nanoparticles (20-40 nm) following high-pressure homogenization treatment. Quantitative evaluation of the lesions showed that remineralization of the lesion with hydroxyapatite nanosuspension led to a significantly higher level of mineral gain compared to the control group (P < 0.05).

CONCLUSION

High-pressure homogenization is an effective method for facile preparation of a stable suspension of hydroxyapatite nanoparticles. Treatment of artificial lesions with nonagglomerated spherical HA nanoparticles improves the remineralization of enamel lesion.

Prevalence and profile of Australian chiropractors treating athletes or sports people: A cross-sectional study

OBJECTIVES

A range of health-care professionals including chiropractors provide treatment for sports-related health problems. This study reports analyses from the first national workforce survey to determine practitioner and practice-related factors associated with the frequent treatment of athletes or sports people by Australian chiropractors.

DESIGN AND SETTING

A 21-item questionnaire collecting information pertaining to practitioner and practice-related characteristics was distributed to all Australian registered chiropractors, as part of the Australian Chiropractic Research Network (ACORN) project and attracted a response rate of 43% (n = 2005). Statistical analyses compared the frequency of treating athletes or sports people against a wide range of relevant practitioner and practice characteristics.

RESULTS

Of the respondents, 49.5% (n = 936) reported frequently treating athletes or sports people, and these chiropractors were more likely to be male as well as report more patient care hours and patient visits per week than those chiropractors who did not frequently treat athletes or sports people. Chiropractors who frequently treat athletes or sports people were also more likely to perform multi-modal management, have multi-disciplinary practitioner relations, use diagnostic equipment and discuss nutrition and medication use as part of their patient care than those chiropractors who did not frequently treat athletes or sports people.

CONCLUSIONS

Nearly half of participating Australian chiropractors treat athletes or sports people frequently. The current and potential role of chiropractors in sports medicine appears significant. Further research is needed to examine the role, practices and outcomes of such chiropractic care helping to, provide treatment and policy development in this area of clinical management.