Demonstrating the feasibility of digital health to support pediatric patients in South Africa

OBJECTIVE

Resources for management of epilepsy in Africa are extremely limited reinforcing the need to develop innovative strategies for optimizing care. Studies have shown that the prevalence of epilepsy in low- and middle-income countries is substantially greater than in more resourced countries. The objective of this report was to demonstrate that mobile Health (mHealth) technologies have the potential to improve the management of epilepsy in Africa.

METHODS

The feasibility of technology-based home monitoring was investigated in an observational study of 40 children with refractory epilepsy or epilepsy associated with intellectual disability and/or behavior difficulties in South Africa. Technology-based home monitoring was implemented for six months. Physical activity, sleep, and heart rate were continuously monitored with a wearable device. Caregivers completed regular mobile Patient Reported Outcomes (mPROs) and reported seizures and ad hoc events using a dedicated app. Feasibility was assessed and descriptively measured for recruitment, retention, and engagement of the participants.

RESULTS

The mHealth technology was able to capture important information that gives an impression of the overall experience of the children and their caregivers. Thirty-seven participants (94.9%) reported at least one clinical event. Seventy-nine percent of caregivers reported seizure events in their children, which were the primary event anticipated. Median engagement with the wearable device and monthly mPROs was 30.8% and 57.1%, respectively. However, most participants (87%) had to be given smartphones for them to have Bluetooth capabilities and access to the study app. Tolerability to the device was impacted by the difficult living circumstances of caregivers that induced fear of loss or theft.

SIGNIFICANCE

The study showed how the use of remote patient monitoring in the form of mHealth can benefit epilepsy patients, despite highly variable engagement with the technology. The combination of mPROs and wearable devices generated informative datasets that will allow clinicians but also the children and their caregivers to better understand and manage the disease.

Symptoms, complications and management of long COVID: a review

Globally, there are now over 160 million confirmed cases of COVID-19 and more than 3 million deaths. While the majority of infected individuals recover, a significant proportion continue to experience symptoms and complications after their acute illness. Patients with 'long COVID' experience a wide range of physical and mental/psychological symptoms. Pooled prevalence data showed the 10 most prevalent reported symptoms were fatigue, shortness of breath, muscle pain, joint pain, headache, cough, chest pain, altered smell, altered taste and diarrhoea. Other common symptoms were cognitive impairment, memory loss, anxiety and sleep disorders. Beyond symptoms and complications, people with long COVID often reported impaired quality of life, mental health and employment issues. These individuals may require multidisciplinary care involving the long-term monitoring of symptoms, to identify potential complications, physical rehabilitation, mental health and social services support. Resilient healthcare systems are needed to ensure efficient and effective responses to future health challenges.

Wearable Technologies for Children with Chronic Illnesses: An Exploratory Approach

OBJECTIVE

To determine the utility of wearable technologies in physical activity assessment in three paediatric diseases, namely, Niemann-Pick C (NP-C), Juvenile Idiopathic Arthritis (JIA) and Duchenne Muscular Dystrophy (DMD).

DESIGN

Exploratory study SETTING AND PATIENTS: Thirty children were recruited across three UK hospitals (Royal Manchester's Children Hospital, Great Ormond Street Children's Hospital, and the Great North Children's Hospital). Ten were diagnosed with NP-C, eight with DMD and twelve with JIA.

INTERVENTION

All participants completed the 6-min walk test (6MWT) at enrolment. Patients were provided with disease-specific smartphone apps paired with a wearable device via Bluetooth. Ambulation was recorded in 30-min epochs measuring average daily maximum (ADM), average daily steps (ADS) and average daily steps per 30-min epoch (ASE).

RESULTS

Median 6MWT results were 450 m, 325 m and 434.5 m for the NP-C, DMD and JIA cohorts, respectively. Wearable data capture was feasible in all three disease cohorts, although complete data capture was not sustained. A statistically significant between-cohort difference was identified for ADM, ADS and ASE. Statistically significant differences were found between DMD/JIA for ADM; NP-C/DMD for ADS and DMD/JIA for ASE.

DISCUSSION

Wearable sensor technologies have the potential to provide additional information for our understanding of ambulation in chronic paediatric disease. The wearable devices were easy to use and popular with patients although key features need to be addressed to appropriately meet study objectives. As the technology continues to evolve at a rapid pace, opportunities to implement child friendly solutions are already available.

A qualitative study exploring caregivers' experiences, perspectives, and expectations for precision medicine in epilepsy in South Africa

PURPOSE

Successful implementation of innovative Precision Medicine initiatives in the management of children with complex epilepsy is largely dependent on the caregivers' engagement with the technology as well as its accessibility and acceptability. We investigated the feasibility of implementing these initiatives in the South African setting by gathering information on the caregivers' experiences, perspectives, and expectations for Precision Management of Epilepsy (PME) initiatives.

METHODS

We purposively recruited 12 participants from a cohort of 40 caregivers of children with complex epilepsy recruited for a PME study attending Red Cross War Memorial Children's Hospital (RCWMCH) in Cape Town, South Africa. Face-to-face semi-structured interviews were conducted using a pragmatic qualitative approach and themes were extracted using a thematic framework approach.

RESULTS

All participants had ideas about the cause of epilepsy, but many did not think that epilepsy is a medical condition. There were several difficulties in adhering to medical treatment which was sometimes combined with traditional remedies and practices. Understanding of Precision Medicine in the context of research was limited and although participants were unclear about benefits, most were optimistic about the future. mHealth devices introduced new feelings and challenges for many participants. The four themes which emerged were: (1) Cause of epilepsy: uncertainty and conflicting views; (2) Need for healing; (3) PME mHealth devices; and (4) Feasibility of implementation of PME initiatives.

CONCLUSION

For Precision Medicine to be widely accepted and beneficial, how people understand the cause of epilepsy, difficulties in adherence to treatment, and personal experiences need to be addressed.

The definition of neuronopathic Gaucher disease

Neuronopathic Gaucher disease (nGD) has a very wide clinical and genotypic spectrum. However, there is no consensus definition of nGD, including no description of how best to diagnostically separate the acute form-Gaucher type 2-from the subacute or chronic form-Gaucher type 3. In this article, we define the various forms of Gaucher disease with particular emphasis on the presence of gaze palsy in all patients with nGD. This consensus definition will help in both clinical diagnosis and appropriate patient recruitment to upcoming clinical trials.

A feasibility study of mHealth and wearable technology in late onset GM2 gangliosidosis (Tay-Sachs and Sandhoff Disease)

Background

As part of a late onset GM2 gangliosidosis natural history study, digital health technology was utilized to monitor a group of patients remotely between hospital visits. This approach was explored as a means of capturing continuous data and moving away from focusing only on episodic data captured in traditional study designs. A strong emphasis was placed on real-time capture of symptoms and mobile Patient Reported Outcomes (mPROs) to identify the disease impact important to the patients themselves; an impact that may not always correlate with the measured clinical outcomes assessed during patient visits. This was supported by passive, continuous data capture from a wearable device.

Results

Adherence rate for wearing the device and completing the mPROs was 84 and 91%, respectively, resulting in a rich multidimensional dataset. As expected for a six-month proof-of-concept study in a disease that progresses slowly, statistically significant changes were not expected or observed in the clinical, mPROs, or wearable device data.

Conclusions

The study demonstrated that patients were very enthusiastic and motivated to engage with the technology as demonstrated by excellent compliance. The combination of mPROs and wearables generates feature-rich datasets that could be a useful and feasible way to capture remote, real-time insight into disease burden.

Measuring disease activity and patient experience remotely using wearable technology and a mobile phone app: outcomes from a pilot study in Gaucher disease

Background

Gaucher disease is an inherited lysosomal storage disorder of which there are three subtypes. Type 1 disease has no neurological involvement and is treatable with enzyme replacement therapy. Type 2 disease results in infant death and type 3 disease is a heterogenous disorder characterised by progressive neurological decline throughout childhood and adult life. Endeavours to find a therapy to modify neurological disease are limited by a lack of meaningful clinical outcome measures which are acceptable to patients.

Results

We present results from a pilot study utilising wearable technology to monitor physical activity as a surrogate of disease activity/severity paired with a mobile phone app allowing patients to complete self-reported outcome measures in the real world as opposed to the hospital environment. We demonstrate feasibility of the approach and highlight areas for development with this study of 21 patients, both children and adults.

Conclusions

We illustrate, where patients engage in the methodology, a rich dataset is obtainable and useful for proactive clinical care and for clinical trial outcome development.

Accuracy of serum procalcitonin for the diagnosis of sepsis in neonates and children with systemic inflammatory syndrome: a meta-analysis

Background

A number of biomarkers have been studied for the diagnosis of sepsis in paediatrics, but no gold standard has been identified. Procalcitonin (PCT) was demonstrated to be an accurate biomarker for the diagnosis of sepsis in adults and showed to be promising in paediatrics. Our study reviewed the diagnostic accuracy of PCT as an early biomarker of sepsis in neonates and children with suspected sepsis.

Methods

A comprehensive literature search was carried out in Medline/Pubmed, Embase, ISI Web of Science, CINAHL and Cochrane Library, for studies assessing PCT accuracy in the diagnosis of sepsis in children and neonates with suspected sepsis. Studies in which the presence of infection had been confirmed microbiologically or classified as “probable” by chart review were included. Studies comparing patients to healthy subjects were excluded. We analysed data on neonates and children separately.

Our primary outcome was the diagnostic accuracy of PCT at the cut-off of 2-2.5 ng/ml, while as secondary outcomes we analysed PCT cut-offs <2 ng/ml and >2.5 ng/ml. Pooled sensitivities and specificities were calculated by a bivariate meta-analysis and heterogeneity was graphically evaluated.

Results

We included 17 studies, with a total of 1408 patients (1086 neonates and 322 children). Studies on neonates with early onset sepsis (EOS) and late onset sepsis (LOS) were grouped together. In the neonatal group, we calculated a sensitivity of 0.85, confidence interval (CI) (0.76; 0.90) and specificity of 0.54, CI (0.38; 0.70) at the PCT cut-off of 2.0-2.5 ng/ml. In the paediatric group it was not possible to undertake a pooled analysis at the PCT cut-off of 2.0-2.5 ng/ml, due to the paucity of the studies.

Conclusions

PCT shows a moderate accuracy for the diagnosis of sepsis in neonates with suspected sepsis at the cut-off of 2.0-2.5 ng/ml. More studies with high methodological quality are warranted, particularly in neonates, studies considering EOS and LOS separately are needed to improve specificity.

Trial registration

PROSPERO Identifier: CRD42016033809. Registered 30 Jan 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2396-7) contains supplementary material, which is available to authorized users.

Important issues in the justification of a control treatment in paediatric drug trials

OBJECTIVE

The value of comparative effectiveness trials in informing clinical and policy decisions depends heavily on the choice of control arm (comparator). Our objective is to identify challenges in comparator reasoning and to determine justification criteria for selecting a control arm in paediatric clinical trials.

DESIGN

A literature search was completed to identify existing sources of guidance on comparator selection. Subsequently, we reviewed a randomly selected sample of comparators selected for paediatric investigation plans (PIPs) adopted by the Paediatric Committee of the European Medicines Agency in 2013. We gathered descriptive information and evaluated their review process to identify challenges and compromises between regulators and sponsors with regard to the selection of the comparator. A tool to help investigators justify the selection of active controls and placebo arms was developed using the existing literature and empirical data.

RESULTS

Justifying comparator selection was a challenge in 28% of PIPs. The following challenging paediatric issues in the decision-making process were identified: use of off-label medications as comparators, ethical and safe use of placebo, duration of placebo use, an undefined optimal dosing strategy, lack of age-appropriate safety and efficacy data, and drug dosing not supported by extrapolation of safety/efficacy evidence from other populations.

CONCLUSIONS

In order to generate trials that will inform clinical decision-making and support marketing authorisations, researchers must systemically and transparently justify their selection of the comparator arm for their study. This report highlights key areas for justification in the choice of comparator in paediatric clinical trials.

Diagnostic value of soluble triggering receptor expressed on myeloid cells in paediatric sepsis: a systematic review

Background

Differential diagnosis between sepsis and non-infectious inflammatory disorders demands improved biomarkers. Soluble Triggering Receptor Expression on Myeloid cells (sTREM-1) is an activating receptor whose role has been studied throughout the last decade. We performed a systematic review to evaluate the accuracy of plasma sTREM-1 levels in the diagnosis of sepsis in children with Systemic Inflammatory Response Syndrome (SIRS).

Methods

A literature search of PubMed, Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and ISI Web of Knowledge databases was performed using specific search terms. Studies were included if they assessed the diagnostic accuracy of plasma sTREM-1 for sepsis in paediatric patients with SIRS. Data on sensitivity, specificity, positive predictive value, negative predictive value, area under receiver operating characteristic curve were extracted. The methodological quality of each study was assessed using a checklist based on the Quality Assessment Tool for Diagnostic Accuracy Studies.

Results

Nine studies comprising 961 patients were included, four of which were in newborns, three in children and two in children with febrile neutropenia. Some data from single studies support a role of sTREM-1 as a diagnostic tool in pediatric sepsis, but cannot be considered conclusive, because a quantitative synthesis was not possible, due to heterogeneity in studies design.

Conclusions

This systematic review suggests that available data are insufficient to support a role for sTREM in the diagnosis and follow-up of paediatric sepsis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13052-016-0242-y) contains supplementary material, which is available to authorized users.

Four-year follow-up of chronic neuronopathic Gaucher disease in Europeans using a modified severity scoring tool

In 2007, the European Task Force for neuronopathic Gaucher disease (NGD) published a review of 55 patients across four countries. Although some observations were possible, analysis was difficult due to the absence of a systematic way of assessing patients. In response to this, a Severity Scoring Tool (SST) was devised to offer a systematic means of assessing the neurological presentation seen. The SST has been modified (mSST) and is a valid tool for monitoring neurological progression. This review describes disease status and progression of neurological manifestations in a cohort of 39 chronic NGD patients across three European countries over a period of 4 years, using the mSST.

Brain white matter abnormalities in paediatric Gaucher Type I and Type III using diffusion tensor imaging

OBJECTIVE

Biomarkers to monitor neurological dysfunction in Neuronopathic Gaucher disease (NGD) are lacking. Diffusion tensor imaging (DTI) is a technique which allows us to probe the microstructure of the white-matter of the brain, in-vivo. The aim of this study was to investigate the value of DTI to visualise and quantify white matter integrity in children with NGD and Type I Gaucher.

DESIGN

DTI was performed and fractional anisotropy (FA), mean diffusivity (MD), axial (λ(axial)) diffusivity and radial (λ(radial)) diffusivity maps calculated. Tract-based spatial statistics (TBSS) was used to perform a voxel-wise statistical analysis of the main white matter structures compared to age-sex matched control groups.

SETTING

The study was performed at Great Ormond Street Children's Hospital NHS Trust

PATIENTS

Four NGD and three Type I Gaucher paediatric patients were recruited

RESULTS

The findings suggest the presence of microstructural white matter changes in NGD patients primarily in the middle cerebellar peduncles compared to an age-sex matched control group. This finding is relevant to the clinical manifestation of ataxia seen in NGD. Diffuse non-specific changes were seen in the Type I patients, but without a focal point.

CONCLUSIONS

This study is the first to use DTI to examine the Gaucher brain. While the numbers studied are small, the results suggest that DTI may be an attractive surrogate marker of NGD, worthy of further exploration for use in clinical studies.

Management of neuronopathic Gaucher disease: revised recommendations

The original guidelines drawn up for the management of the neuronopathic forms of Gaucher disease were felt to be in need of revision; in particular, the role of high-dose enzyme replacement therapy (120 IU/kg of body weight every 2 weeks) in stabilizing neurological disease. The existing published evidence was analysed; it was concluded that it did not support the role of high-dose ERT, although this might be required to treat severe visceral disease.

Outcome of type III Gaucher disease on enzyme replacement therapy: review of 55 cases

The European Task Force for Neuronopathic Gaucher Disease (NGD) met in 2006 to review its 2001 guidelines. Fifty-five patients from five European countries were reviewed; 29 were male and 26 female. The majority of the patients were homozygous for the L444P mutation. All had been on enzyme replacement therapy (ERT). However, there was considerable variation in the dose of ERT, as well as an uneven distribution of risk factors. Thus, the oldest patients were on the lowest doses, and several had had a total splenectomy, while the youngest patients had a high proportion of compound heterozygosity and were on the highest doses, and very few had had a splenectomy. This heterogeneity rendered analysis very difficult. However, some observations were possible. The older patients appeared to remain relatively stable despite a low dose of ERT. In the younger patients, there was no clear effect of high-dose ERT. However, the period of follow-up was too short in many patients to draw valid conclusions. These data will be used to draw up revised guidelines.

A severity scoring tool to assess the neurological features of neuronopathic Gaucher disease

Type III Gaucher disease is one of the three recognized subtypes of Gaucher disease, an inherited deficiency of lysosomal glucocerebrosidase. Phenotypically there is a wide spectrum of visceral and neurological manifestations. Enzyme replacement is effective in managing the visceral disease; however, the neurological manifestations remain a more challenging obstacle. There is an unfulfilled need to reliably monitor neurological disease and its response to treatment. A severity scoring tool was developed through neurological domain identification, item generation and tool formation. Domain identification was established based on a retrospective single centre study (n = 15) and a systematic review of publications. Forty-seven patients with neuronopathic Gaucher disease were then assessed using the tool to establish the clinical and statistical reliability of each domain. Judgement quantification of the tool was established through a process of content validity involving five European experts. Content validity is considered to be most effective when undertaken systematically. Concurrent validity and feasibility of the tool was also highlighted. This process allowed a revised and validated version of the tool to be developed.

Comparison of ethyl chloride spray with topical anaesthetic in children experiencing venepuncture

AIM

Initial validation of ethyl chloride spray in minimising pain for children experiencing venepuncture in comparison to Ametop cream.

DESIGN

A randomised non-inferiority cross-over trial comparing ethyl chloride with Ametop in 77 children aged five to 13 years undergoing measurement of glomerular filtration rate. Additional data were gathered on the child's preferred choice for the third venepuncture.

RESULTS

Ethyl chloride spray is of equal preference to Ametop in children experiencing venepuncture, with lower self-reported pain score. It should be considered as an added alternative option to topical anaesthetic but further work is needed to clarify application technique.

Clinical evaluation of ferric oxalate in relieving dentine hypersensitivity

Previous in vitro permeability and scanning electron microscopic (SEM) studies have demonstrated the effectiveness of the oxalate ion in dentine permeability reduction and effective tubule occlusion. The aim of this randomized double-blind, split mouth 4-week clinical study, therefore was to determine whether a 1-min application of ferric oxalate (Sensodyne Sealant) on exposed root dentine was effective in reducing dentine hypersensitivity (DH). Thirteen subjects [8F:5M, mean age 46.2 (s.d. 4.15) years] completed the study. The subjective response was evaluated by tactile, thermal and evaporative methods of assessment. Data were collected at baseline and post-application at +5 min and 4 weeks. Analysis was based on paired t-test (P=0.05) and Wilcoxon-Mann-Whitney tests. No statistically significant differences were noted between ferric oxalate and placebo preparations at +5 min and 4 weeks for any of the test stimuli. There was, however, a clear trend towards immediate reduction (+5 min) in DH reverting back to baseline values at 4 weeks with the exception of the Biomat Thermal Probe mean values, which maintained the reductions in DH compared with placebo. The results of the present study demonstrated that a 1-min application of ferric oxalate is both rapid and effective in reducing DH although its long-term effectiveness still needs to be determined.

The effects of reconditioning on the slot dimensions and static frictional resistance of stainless steel brackets

This study investigated the effects of reconditioning on the slot dimensions and the static frictional resistance of stainless steel brackets at 0, 5, and 10 degrees bracket/archwire angulation. A sample of 45 used, commercially reconditioned 0.018 x 0.030 inch stainless steel standard edgewise brackets was compared with a matched sample of 45 new brackets. The slot dimensions of 15 new and 15 reconditioned brackets were examined using a photomicroscope. With new brackets both the occluso-gingival slot width (mean = 0.0197 inch) and slot depth (mean = 0.0304 inch) exceeded the manufacturer's nominal dimensions of 0.018 x 0.030 inch. The reconditioning process resulted in a further increase in slot width (mean = 0.0205 inch), which was statistically significant (P = 0.028), and a reduction in slot depth (mean = 0.0291 inch), which was highly statistically significant (P = 0.002). This may be attributable to preferential metal removal by the electro-polishing phase of the reconditioning process. Friction testing of 30 new and 30 reconditioned brackets demonstrated that both showed an increase in binding effects as the bracket/archwire angulation was increased from 0 to 5-10 degrees. However, the changes in slot dimensions secondary to reconditioning did not result in a statistically significant difference in mean static frictional resistance when the two bracket types were compared. Although the brackets were altered physically by the reconditioning process, their performance during simulated sliding mechanics was not adversely affected. This implies that reconditioning may not result in clinically significant effects.

The crystal growth technique--a laboratory evaluation of bond strengths

An ex vivo study was carried out to determine differences in the bond strengths achieved with brackets placed using a crystal growth technique compared with a conventional acid-etch technique. A solution of 37 per cent phosphoric acid was used for acid-etching and a commercially available polyacrylic acid gel, Crystal-lok for crystal growth. A heavily-filled composite resin was used for all samples to bond brackets to healthy premolar teeth extracted for orthodontic purposes. Polycrystalline ceramic and stainless steel brackets were used and tested to both tensile and shear failure using an Instron Universal Testing machine. The tensile and shear bond strengths were recorded in kgF. In view of difficulties experienced with previous authors using different units to describe their findings, the data were subsequently converted to a range of units in order to facilitate direct comparison. The crystal growth technique produced significantly lower bond strengths than the acid-etch technique for ceramic and stainless steel brackets, both in tensile and shear mode. The tensile bond strength for stainless steel brackets with crystal growth was 2.2 kg compared with 6.01 kg for acid-etch, whilst with ceramic brackets the tensile bond strengths were 3.9 kg for crystal growth and 5.55 kg for acid-etch. The mean shear bond strength for stainless steel brackets with crystal growth was 12.61 kg compared with 21.55 kg for acid-etch, whilst with ceramic brackets the shear bond strengths were 7.93 kg with crystal growth compared with 16.55 kg for acid-tech. These bond strengths were below those previously suggested as clinically acceptable.

A comparison between the wear resistance of three types of denture resin to three different dentifrices

This study compares the abrasive effects of three dentifrices on three different denture base resins, a heat cured acrylic resin, a self cured acrylic resin and a light activated urethane dimethacrylate-based resin. Specimens of the resins were subjected to a regimen of mechanical brushing using measured amounts of paste on standard toothbrushes driven by a reciprocating device. The apparent wear of each specimen was assessed qualitatively using scanning electron microscopy and quantitatively using profilometry and reflex microscopy. The study showed that cleaning pastes play a significant role in the wear of conventional acrylic resins, the relative abrasivity of the dentifrices being substrate related. However, wear was less evident on the light activated urethane dimethacrylate resin. Brushing with water alone produced no detectable wear on any of the specimens.

A comparison of self-ligating and conventional orthodontic bracket systems

This ex-vivo study compared the static frictional resistance of three self-ligating brackets with a conventional steel-ligated Ultratrimm bracket. The effects of archwire size (0.020, 0.019 x 0.025 and 0.021 x 0.025-inch), bracket/archwire angulation (0, 5 and 10 degrees) and the presence of unstimulated human saliva were investigated. The study demonstrated that both increases in wire size and bracket/archwire angulation resulted in increased static frictional resistance for all bracket types tested, with the presence of saliva having an inconsistent effect. Mobil-Lock Variable-Slot had the least friction for all wires for 0 degree angulation. However, with the introduction of angulation, the values were comparable to those of the other brackets. Activa brackets had the second lowest frictional resistance, although high values were found with 0.019 x 0.025-inch wires. SPEED brackets demonstrated low forces with round wires, although with rectangular wires or in the presence of angulation, friction was greatly increased. Ultratrimm brackets produced large individual variation, confirming the difficulty in standardizing ligation force, although under certain conditions, significantly larger frictional forces were observed. In conclusion, self-ligating brackets showed reduced frictional resistance in comparison to steel ligated brackets only under certain conditions.

Adhesive composite resins for artificial teeth: a laboratory investigation of bond strength to a cobalt-chromium alloy

Adhesive resin systems are reported to improve the bond strength between resins and cast cobalt-chromium alloy. This investigation compares the behaviour of three resin systems. Cylinders and beams of cobalt-chromium, with 0.6-mm-diameter retention beads regularly cast onto the bonding surfaces, were air-abraded and ultrasonically cleaned. Resin veneers 4 mm deep on the cylinders and 2 mm on the bars were polymerized by heat and pressure or by light. Specimens were water-stored for 7 or 90 days, including thermocycling between 4, 37 and 60 degrees C, before testing in a Universal Testing Machine to examine the shear bond strength or the effect of the bonded resin spine on the flexural strength of the beams using a three-point bend test. Specimens were examined with an optical microscope to attempt to determine the nature of the failures that occurred. The investigation showed that, overall, the heat- and pressure-cured urethane dimethacrylate resin with and adhesive based upon methacrylic acid performed significantly less well than a conventional acrylic resin, or a hybrid composite resin with and adhesive monomer.

The bactericidal effects of dental ultrasound on Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis. An in vitro investigation

This study investigated the possible bactericidal acoustic effects of the dental ultrasonic scaler. Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis suspensions, were subjected to the vibrations of a Cavitron P1 insert for 2.5 and 5.0 min in an acoustically-simulated pocket model and the survivors enumerated. The extent of any cavitation occurring within the pocket model to which the statistically significant bactericidal activity observed might be attributed, was determined by 'sonoluminescence', which was then investigated by photomultiplication techniques. However, these failed to detect any sonoluminescence within the pocket space and, moreover, the necessary deflection of the water coolant away from the insert tip, to avoid flooding of the experimental pocket, proved to result in temperatures of 47.6 degrees C and 52.3 degrees C at the respective time intervals, and thereby constituted an alternative possible bactericidal mechanism. Examination of the effects of such temperature changes on the target bacteria then revealed statistically significant differences in the viable counts of both microorganisms after 5.0-min periods, and as such were comparable to those previously detected in relation to the pocket model. Whilst it must be presumed that the bacteriolytic effect observed in the main investigation was due to the incidental temperature changes, in the absence of acoustic cavitation the influence of any associated acoustic microstreaming cannot be discounted. Further investigations to assess the bactericidal potential of acoustic phenomena using a modified experimental to exclude any hyperthermic effects are therefore necessary.

Method for enhancing the fluoride release of a glass-ionomer cement

The cariostatic action of the glass-ionomer cement has been attributed to its sustained release of fluoride. The fluoride in the set cement originates from the glass particles which are eroded, in part, during the setting reaction. In this study a water-activated glass-ionomer was mixed with sodium fluoride (NaF) solutions of different concentrations (0%, 2% and 4%). The different cements were used to prepare discs which were stored individually in demineralized water at 37 degrees C, the fluoride concentration of the storage solutions were measured, at intervals, until the specimens were 80 days old. The effect of the different mixing solutions on the working and setting times and compressive strength were also determined. It was found that the cement mixed with the 4% solution of NaF released significantly more fluoride than the water mixed control. The fluoride solution mixed materials had longer setting times than the control, but there was no significant difference in the compressive strengths. All the materials became progressively stronger on storage. Mixing the cement with a 4% solution of NaF increased the initial fluoride release of the glass-ionomer without seriously affecting other physical properties.