Axillary tumour burden in women with one abnormal node on ultrasound compared to women with multiple abnormal nodes.

AIM: To determine if the number of abnormal nodes seen on preoperative axillary ultrasound (AUS) is a predictor of the number of positive nodes at histology for women with needle-biopsy-proven positive nodes. MATERIALS AND METHODS: This prospective multicentre cohort study included consecutive patients with early breast cancer who had needle-biopsy-proven positive nodes on AUS and underwent axillary lymph node dissection (ALND) between October 2015 and July 2016. The number of abnormal nodes at preoperative AUS was recorded by breast radiologists or radiographers. RESULTS: One hundred and twenty-three patients were included in the study. The median age of the women was 62 (range 30-93) years. Fifty-four of the 123 (44%) women had one abnormal node, whereas 69 (56%) had multiple abnormal nodes on AUS. Forty of the 123 (33%) women had two or fewer nodes with metastases at histology after ALND. Tumours ≤20 mm (p<0.001) and one abnormal node on AUS (p<0.001) were associated with two or fewer nodes with metastases at ALND. Both remained significant in logistic regression analysis. The likelihood of at least three metastases based on the combination of these two factors had 95% sensitivity (79 of 83), 35% specificity (14 of 40), a negative predictive value of 78% (14 of 18), and a positive predictive value of 75% (79 of 105). CONCLUSION: Among women with needle-biopsy-proven positive nodes, around three in four women (78%) with an invasive tumour ≤2 cm and one abnormal node on AUS have two or fewer positive nodes at ALND. These women are overtreated by upfront ALND and can be offered sentinel node biopsy (SNB).

Axillary tumour burden in women with a fine-needle aspiration/core biopsy-proven positive node on ultrasonography compared to women with a positive sentinel node.

BACKGROUND: The sensitivity of axillary ultrasonography (AUS) has increased in recent years, enabling detection of even low-volume axillary nodal metastases. The aim here was to evaluate the axillary tumour burden in women with a fine-needle aspiration/core biopsy-proven positive node on AUS and in those with a positive sentinel node biopsy (SNB). METHODS: This retrospective cohort study included all patients with early breast cancer who had AUS and axillary lymph node dissection (ALND) between 2011 and 2014. RESULTS: A total of 332 patients who had ALND were eligible for the study, 191 (57·5 per cent) in the AUS-positive group and 141 (42·5 per cent) in the SNB-positive group. Patients in the AUS-positive group were older at diagnosis (P = 0·018), more likely to have larger tumours (P = 0·002), higher tumour grade (P = 0·005), positive human epidermal growth factor 2 status (P = 0·015), and negative oestrogen receptor status (P < 0·001). The AUS-positive group also had a larger number of lymph nodes with macrometastases (P < 0·001) and were more likely to have extranodal invasion (P < 0·001). In the AUS-positive group, 40·3 per cent of patients (77 of 191) had only one or two nodes with macrometastases identified at histology after ALND. Tumour size no larger than 20 mm, invasive ductal or lobular histology and breast-conserving surgery were associated with the presence of two or fewer macrometastases at ALND. Only tumour size and tumour histology remained significant in multiple logistic regression analysis. CONCLUSION: Patients with AUS-detected metastases had a higher axillary tumour burden than those with SNB-detected metastases. Around 40 per cent of patients with AUS-detected nodal disease had one or two nodes with macrometastases and were thus overtreated by ALND.

Results of a national training programme in sentinel lymph node biopsy for breast cancer.

BACKGROUND: New Start, a structured, validated, multidisciplinary training programme in sentinel lymph node biopsy (SLNB), was established to allow the introduction and rapid transfer of appropriate knowledge and technical skills to ensure safe and competent practice across the UK. METHODS: Multidisciplinary teams attended a theory/skills laboratory course, following which they performed 30 consecutive SLNBs, either concurrently with their standard axillary staging procedure (training model A) or as stand-alone SLNB (training model B). SLNB was performed according to a standard protocol using the combined technique of isotope ((99m) Tc-labelled albumin colloid) and blue dye. An accredited New Start trainer mentored the first five procedures in the participant's hospital, or all 30 if stand-alone. Validation standards for model A and B were a localization rate of at least 90 per cent. In addition, for model A only, in which a minimum of ten patients were required to be node-positive, a false-negative rate (FNR) of 10 per cent or less was required. RESULTS: From October 2004 to December 2008, 210 SLNB-naive surgeons, in 103 centres, performed 6685 SLNB procedures. The overall sentinel lymph node (SLN) localization rate was 98·9 (95 per cent confidence interval 98·6 to 99·1) per cent (6610 of 6685) and the FNR 9·1 (7·9 to 10·5) per cent (160 of 1757). The FNR was related to nodal yield, ranging from 14·8 per cent for one node and declining to 9·7, 6·6, 4·7 and 4·1 per cent for two, three, four and more than four SLNs respectively. No learning curve was identified for localization or FNR. CONCLUSION: The programme successfully trained a wide range of UK breast teams to perform safe SLNB and suggested that a standard injection protocol and structured multidisciplinary training can abolish learning curves.

In situ randomised trial to investigate the occluding properties of two desensitising toothpastes on dentine after subsequent acid challenge.

OBJECTIVES: The aim of the study was to determine in situ the relative abilities of two desensitising toothpastes to occlude dentinal tubules with or without acid challenge. MATERIALS AND METHODS: The study design was a single centre, randomised, split mouth crossover model examining four treatments over two periods. The primary outcome was the degree of occlusion proffered by two desensitising toothpastes [Sensodyne® Rapid Relief (8% strontium acetate, 1040 ppm sodium fluoride) and Colgate® Sensitive Pro-ReliefTM daily (8% arginine, 1450 ppm sodium monofluorophosphate)], a standard toothpaste (1450 ppm sodium fluoride) and water, after acid challenge. Healthy adult volunteers wore bi-lateral lower buccal appliances each with two dentine sections, receiving two treatments per study period. Samples were brushed twice a day with treatment, with two additional 3-min extra-oral acidic challenges applied ex vivo on days 3 and 4. A secondary outcome was the degree of occlusion attained in the absence of acid challenge. Examiners blinded to the study assessed occlusion by visual score of post-treatment scanning electron microscope images. RESULTS: All 28 participants completed the study. In the absence of acid challenge, occlusion scores for both desensitising toothpastes were similar and significantly better than control scores (p < 0.02). After acid challenge both desensitising toothpastes occluded more effectively than controls; however, occlusion scores for the strontium acetate paste were significantly greater than those of the arginine paste (p < 0.02). CONCLUSIONS: The occluding properties of the strontium acetate toothpaste were significantly more robust after acid challenge than those of the arginine toothpaste. CLINICAL RELEVANCE: Patients with hypersensitivity, regularly imbibing dietary acidic drinks, should be advised that Sensodyne® Rapid Relief provides robust tubule occlusion despite repeated acidic challenges.

An evaluation of CPD activity of dentists in Wales.

INTRODUCTION: Ongoing professional education is essential for dental professionals to maintain and update their clinical skills and knowledge. There is a current trend towards mandatory Continuing Professional Development (CPD) for dentists within Europe and beyond. Mandatory CPD will ensure high professional standards and enable mobilisation of the dental workforce within Europe. In 2002, the UK General Dental Council (GDC) implemented a system of mandatory CPD for dentists practicing in the UK. The Wales Deanery is situated in the School of Postgraduate Medical and Dental Education, Cardiff University. It provides verifiable CPD courses for dentists and dental care professionals (DCPs) currently practicing in Wales and has recorded professionals' attendance on these courses since 2001. The project aimed to investigate the CPD activity of dentists in Wales, using these data. METHODS: The Wales Deanery database holds data on the CPD courses undertaken by 1178 dentists working in Wales since 2001. A number of hypotheses were investigated using a variety of statistical methods. RESULTS: Dentists were undertaking significantly fewer hours of CPD in Mid and West Wales compared to the North and South of the principality. Sole practitioners were found to engage in less CPD than those in group practices, but these differences did not reach statistical significance. Dentists who employed a hygienist or therapist completed more hours of CPD than those who didn't employ either. There were no gender differences in engagement in CPD. CPD participation was consistently and significantly higher in mid and late career than in early career. CONCLUSIONS: This study provides a greater understanding of the CPD habits of the dental workforce in Wales. Practice staffing levels, location of practice and time since graduation were found to have the greatest impact on engagement in CPD activity. These findings will be used by the Deanery to inform future education provision for dental professionals in Wales.

Comparison of malleable stylet and reusable and disposable bougies by paramedics in a simulated difficult intubation.

In a randomised crossover study, 60 ambulance paramedics attempted tracheal intubation of a manikin model of a Cormack and Lehane grade 3/4 view using a Portex stylet, Portex and Frova single-use bougies, and a Portex reusable bougie. Tracheal intubation within 30 s was achieved by 34/60 (57%) using the stylet, 18/60 (30%) using a Portex single-use bougie, 16/60 (27%) using a Frova single-use bougie and 5/60 (8%) using a Portex reusable bougie. The proportion intubating within 30 s was significantly higher with the stylet compared with any bougie (p < 0.001), but significantly lower with a Portex reusable bougie than any other device (p < 0.004). Participants rated the Portex reusable bougie as significantly more difficult to use than the other devices (p < 0.001). There was no evidence of a relationship between previous experience and success rate for any device.

Continuing dental education: evaluation of the effectiveness of a disinfection and decontamination course.

AIM: To evaluate a disinfection and decontamination dental postgraduate course run by the Wales Dental Postgraduate Deanery between 2008 and 2010. METHODS: Pre- and post-course multiple choice questionnaires were completed by 1177 course attendees. Mean scores before and after participation on the training course were compared and analysed. RESULTS: Mean pre-course score was 45.3%, rising to 87.0% in the post-course assessment, reflecting an improvement of 41.8%. Prior to training, 30.7% achieved a satisfactory score of 13/20 (65%) compared to 98.3% on completion of training. Dental technicians were found to score significantly lower than other occupation groups both before and after course attendance. Decade of graduation had no effect on results. Theoretical microbiology was the question area which showed least improvement. CONCLUSION: Attending the disinfection and decontamination course significantly improved participants' knowledge. Theoretical microbiology, as a topic area, may be targeted for improvements in future courses to improve results further.

Continuing dental education in radiation protection: knowledge retention following a postgraduate course.

OBJECTIVE: To evaluate medium-term knowledge retention of dental personnel following attendance at a postgraduate course in radiation protection. SUBJECTS AND METHODS: Knowledge was measured using identical pre- and post-course validated single best-answer multiple-choice instruments, administered immediately before and after training and at follow-up at 6 or 12 months. These comprise 16 questions each with 5 choices. The range of possible scores was from 0 to 16, and scores were scaled to percentages. Participants were predominantly dental practitioners, but a minority consisted of dental care professionals (dental nurses, hygienists and therapists). Of 285 participants, 272 (95.4%) completed both pre- and post-course questionnaires. One hundred and seventeen (43%) of these also completed the follow-up test, but only 109 (40%) individuals could be linked to the original course. RESULTS: Mean (standard deviation) pre-, post-course and follow-up-corrected percentage scores were 39.1 (16.1), 74.6 (16.9) and 58.9 (22.7), respectively. There was attrition in knowledge at follow-up: the average increase in adjusted score after training was 35.5 points, but only 56% of this was retained at follow-up. Paired t-tests confirmed that the mean score at follow-up was firmly intermediate between the pre- and post-course scores. Of the 109 participants, 7 (6%) achieved a satisfactory score pre-training, 82 (75%) immediately post-training and 41 (38%) at follow-up. There were gross differences between the levels of performance achieved for the eight subject areas tested. CONCLUSION: Immediate post-course assessments have indicated that current postgraduate courses in radiation protection are effective. However, a substantial amount of knowledge is lost by 6-12 months following course attendance. To achieve long-term knowledge retention, early or repeated reinforcement may be necessary.

Can abdominal bioelectrical impedance refine the determination of visceral fat from waist circumference?

Ryo et al (2005 Diabetes Care 28 451-3) reported a new method for measuring the visceral fat area (VFA) by combining abdominal bioelectrical impedance analysis (BIA) with measurement of waist circumference (WC), but very few methodological details were provided. Furthermore, the study did not test the use of WC alone as an indicator of VFA even though others had previously reported a strong correlation. We sought to determine the optimal measurement technique and analysis for measuring VFA by abdominal BIA and WC. 18 volunteers (age 23-64 years) underwent measurement of WC, abdominal impedance (Bodystat 500 four-electrode system) and a single cross-sectional CT scan at the umbilicus. VFA derived using WC(3) and measurements of abdominal impedance from electrode pairs sited at the flank predicted the value of VFA measured by CT with correlation r = 0.904 (p < 0.0001); the optimizing power of WC was 3.3 (r = 0.905). However, the use of WC(1.9) alone, without involving BIA at all, provided a similar correlation (r = 0.923). Our small preliminary study shows that abdominal BIA is potentially a practicable non-invasive technique for measurement of VFA but casts doubt on whether it adds any value to the use of WC alone. Larger studies are now required to test this finding.

A comparative study of image quality and radiation exposure for dental radiographs produced using a charge-coupled device and a phosphor plate system.

AIM: To investigate the quality of periapical radiographic images produced by two digital dental radiography systems, a charge-coupled device (CCD) and a photostimulable phosphor (PSP) image plate system, and to examine the overall radiation exposure when using these systems in a clinical setting. METHODOLOGY: Patients were randomly allocated to both systems and the resultant radiographs rated for quality. The expected radiation exposure for an investigation was calculated. RESULTS: Overall, 98 images were acquired using the CCD system and 108 with the PSP system. The PSP system produced significantly higher quality (P < 0.001) periapical images compared with the CCD system. The CCD system required significantly more (P < 0.001) repeat exposures to obtain a diagnostic image than the PSP system but at a lower expected radiation exposure. CONCLUSIONS: The image quality was superior using the phosphor plate system. Although more repeat radiographs were required using the CCD system, the images were produced with a lower expected radiation exposure.

Hospital infection society prevalence survey of Healthcare Associated Infection 2006: comparison of results between Northern Ireland and the Republic of Ireland.

As part of the Third Healthcare Associated Infection (HCAI) Prevalence Survey of the United Kingdom and Ireland, HCAI point prevalence surveys were carried out in Northern Ireland (NI) and the Republic of Ireland (RoI). Here we explore the potential benefits of comparing results from two countries with different healthcare systems, which employed similar methodologies and identical HCAI definitions. Forty-four acute adult hospitals in the RoI and 15 in NI participated with a total of 11 185 patients surveyed (NI 3644 patients and RoI 7541). The overall HCAI prevalence was 5.4 and 4.9 in NI and the RoI, respectively. There was no significant difference in prevalence rates of HCAI, device-related HCAI or HCAI associated with bloodstream infection but there was a difference in meticillin-resistant Staphylococcus aureus-related HCAI (P = 0.02) between the two countries. There were significantly more urinary tract infections and Clostridium difficile infections recorded in NI (P = 0.002 and P < 0.001). HCAIs were more prevalent in patients aged >65 years and in the intensive care unit in both countries. HCAIs were also more prevalent if patients were mechanically ventilated, had had recent non-implant surgery (RoI) or had more recorded HCAI risk factors. This is the first time that HCAI prevalence rates have been directly compared between NI and the RoI. By closely examining similarities and differences between HCAI prevalence rates in both countries it is hoped that this will influence healthcare planning and at the same time reassure the public that HCAI is important and that measures are being taken to combat it.

Four country healthcare associated infection prevalence survey 2006: risk factor analysis.

Point prevalence surveys are useful in detecting changes in the pattern of healthcare-associated infection (HCAI). In 2004 the Hospital Infection Society was asked to conduct a third national prevalence survey, which included England, Wales, Northern Ireland and the Republic of Ireland. A similar but not identical survey was carried out in Scotland. Data were collected on standardised forms using Centres for Disease Control and Prevention definitions. This report considers associations with a wide range of risk factors for all HCAI and for four main categories. The overall prevalence rate of HCAI was 7.6% and increased significantly with age. All risk factors considered were associated with highly significantly increased risk of HCAI, except recent peripheral IV catheter and other bladder instrumentation use. Primary bloodstream infection (PBSI) was associated with antibiotic, central intravenous catheter and parenteral nutrition use. Pneumonia was associated with antibiotic, central catheter, parenteral nutrition use, mechanical ventilation and current peripheral catheter use. Surgical site infection was associated with recent surgery, antibiotic and central catheter use, mechanical ventilation and parenteral nutrition. Urinary instrumentation and antibiotic use were associated with urinary tract infection. Patients under a critical care medicine consultant had the highest prevalence of HCAI (23.2%). This report highlights those areas requiring attention to prevent HCAI, i.e. device-related infections such as PBSI (e.g. central catheters) and pneumonia (e.g. mechanical ventilation) and should influence protocols for future prevalence surveys of HCAI, e.g. the recording of risk factors at the time of assessment only is sufficient.

Four country healthcare associated infection prevalence survey 2006: overview of the results.

A survey of adult patients was conducted in February 2006 to May 2006 in acute hospitals across England, Wales, Northern Ireland and the Republic of Ireland to estimate the prevalence of healthcare-associated infections (HCAIs). A total of 75 694 patients were surveyed; 5743 of these had HCAIs, giving a prevalence of 7.59% (95% confidence interval: 7.40-7.78). HCAI prevalence in England was 8.19%, in Wales 6.35%, in Northern Ireland 5.43% and in the Republic of Ireland 4.89%. The most common HCAI system infections were gastrointestinal (20.6% of all HCAI), urinary tract (19.9%), surgical site (14.5%), pneumonia (14.1%), skin and soft tissue (10.4%) and primary bloodstream (7.0%). Prevalence of MRSA was 1.15% with MRSA being the causative organism in 15.8% of all system infections. Prevalence of Clostridium difficile was 1.21%. This was the largest HCAI prevalence survey ever performed in the four countries. The methodology and organisation used is a template for future HCAI surveillance initiatives, nationally, locally or at unit level. Information obtained from this survey will contribute to the prioritisation of resources and help to inform Departments of Health, hospitals and other relevant bodies in the continuing effort to reduce HCAI.

Volume and outcome for major upper GI surgery in England.

BACKGROUND: The correlation between hospital or surgeon volume and outcome for complex surgical procedures has been the subject of several studies in recent years. In the UK, such studies have been used to strengthen the case for centralization of such procedures. The recent availability of easily accessible and fully independent data on hospital outcomes for surgical services in the UK has provided the opportunity to review any potential associations between volume and outcome in the UK. METHODS: Hospital Episode Statistic (HES) data were collected through Dr Foster for four different upper GI procedures (gastrectomy, esophagectomy, pancreaticoduodenectomy, and liver resection) for a 6-year period from 1999 to 2005. Data for each procedure were divided into volume-dependant quartiles to assess any differences in mortality outcome. RESULTS: Generally, mortality rates for all four procedures are lower than previously studies have suggested. A significant trend favoring high volume providers was noted for esophagectomy, with mortality rates varying from 7.8% to 4.0% for lowest to highest volume providers (p < 0.001). A similar but less clear-cut trend was noted for pancreaticoduodenectomy. There was no significant difference for gastric and liver resection between low- and high-volume providers. There was a 20% decrease in centers performing esophagectomy and 28% for centers performing pancreaticoduodenectomy. CONCLUSION: There is a volume outcome association for esophagectomy and pancreaticoduodenectomy. There is no association for gastrectomy or hepatectomy.

A national scheme for public access defibrillation in England and Wales: early results.

BACKGROUND: Automated external defibrillators (AEDs) operated by lay persons are used in the UK in a National Defibrillator Programme promoting public access defibrillation (PAD). METHODS: Two strategies are used: (1) Static AEDs installed permanently in busy public places operated by those working nearby. (2) Mobile AEDs operated by community first responders (CFRs) who travel to the casualty. RESULTS: One thousand five hundred and thirty resuscitation attempts. With static AEDs, return of spontaneous circulation (ROSC) was achieved in 170/437 (39%) patients, hospital discharge in 113/437 (26%). With mobile AEDs, ROSC was achieved in 110/1093 (10%), hospital discharge in 32 (2.9%) (P<0.001 for both variables). More shocks were administered with static AEDS 347/437 (79%) than mobile AEDs 388/1093 (35.5%) P<0.001. Highly significant advantages existed for witnessed arrests, administration of shocks, bystander CPR before arrival of AED and short delays to start CPR and attach AED. These factors were more common with static AEDs. For CFRs, patients at home did less well than those at other locations for ROSC (P<0.001) and survival (P=.006). Patients at home were older, more arrests were unwitnessed, fewer shocks were given, delays to start CPR and attach electrodes were longer. CONCLUSIONS: PAD is a highly effective strategy for patients with sudden cardiac arrest due to ventricular fibrillation who arrest in public places where AEDs are installed. Community responders who travel with an AED are less effective, but offer some prospect of resuscitation for many patients who would otherwise receive no treatment. Both strategies merit continuing development.

Prevalence of gingival recession and study of associated related factors in young UK adults.

OBJECTIVES: To determine the prevalence of gingival recession (GR) and associations with dentine hypersensitivity (DH), erosive toothwear (BEWE), gingival bleeding (BOP) and periodontal pocketing (PPD) in young European adults. MATERIALS AND METHODS: This is a secondary analysis using data collected from 350 UK participants enrolled in a European cross sectional study of 3187 young adults. GR, BOP, PPD, DH (participant and clinician assessment) and BEWE were recorded. A questionnaire assessed demographics, oral hygiene and lifestyle habits. RESULTS: 349 participants completed the study. GR, BOP and PPD showed the same pattern of distribution, prevalence increasing from incisors to molars in upper and lower arches for buccal and palatal scores. Every participant exhibited recession affecting at least 1 tooth, 42% having a maximum recession of 4-8 mm. There was a significant and linear association demonstrating an increase in maximum recession with age. DH and BEWE produced a similar pattern to buccal periodontal indices, the premolars being most affected. Maximum recession correlated significantly with maximum DH (participant and Schiff), PPD, BOP, BEWE (scores of 2/3), BMI (≥25 kg/m2) and unsystematic brushing motion. 94% of the study population exhibited some BOP at one or more sites. 5% of the population had periodontal pocketing ≥4 mm, 46% had DH and 80% BEWE 2/3. CONCLUSION: Widespread recession and gingivitis with minimal periodontal disease was observed. Every participant exhibited at least one tooth with recession. Many teeth did not exhibit DH despite prevalent recession and severe erosive toothwear. Recession correlates to a number of oral and lifestyle variables. CLINICAL SIGNIFICANCE: Recession in young adults is multifactorial and highly prevalent. It can result in DH and consequential increase in demand for treatment relating to both pain and aesthetics. Further research is needed to understand the underlying aetiology to prevent recession occurring.

The effect of saliva derived from different individuals on the erosion of enamel and dentine. A study in vitro.

UNLABELLED: The aim of this study was to determine if saliva from 14 subjects afforded different levels of protection to human enamel and dentine against erosion in vitro. Test specimens were exposed for 2 h to saliva and control specimens to water for 2 h followed by citric acid for 10 min. This cycle was carried out 12 times. Tissue loss measured by contact profilometry was highly significantly different between subjects. Erosion was significantly reduced by pre-treatment with saliva from 7 subjects (enamel) or 6 subjects (dentine). Saliva from 1 subject resulted in significantly more enamel erosion than control. CONCLUSION: Saliva from different donors affords different levels of protection against erosion.

A clinical study in situ to assess the effect of a food approved polymer on the erosion potential of drinks.

OBJECTIVES: The consumption of acidic soft drinks continues to rise as do concerns regarding effects of frequent intake. The aim of the study was to determine the effect of acidic soft drinks containing food approved polymers, on dental enamel. METHODS: The study design was a single blind, randomised, five-treatment crossover clinical trial involving 15 healthy dentate subjects. Subjects wore an upper removable acrylic appliance retaining two enamel specimens and consumed 250ml of beverage four times/day for 10 days. The following beverages were tested: (1) unmodified acidic soft drink, (2) experimental acidic soft drink with 0.02% polyphosphate, (3) experimental acidic soft drink with 0.02% polyphosphate and 0.01% calcium, (4) experimental acidic soft drink with 0.02% polyphosphate and 0.03% xanthan gum, and (5) mineral water. Tissue loss was measured at days 5 and 10 of each study leg using a profilometer. RESULTS: The order of erosion from most to least at day 10 was unmodified acidic soft drink>experimental acidic soft drink with polyphosphate>experimental acidic soft drink with polyphosphate+gum>experimental acidic soft drink with polyphosphate+calcium>mineral water. At day 10 the unmodified acidic soft drink was significantly (p=0.001) more erosive than all other drinks. CONCLUSIONS: Unmodified acidic soft drink with the addition of polyphosphate alone or combined with calcium or xanthan gum are all effective at reducing erosion of enamel compared with the unmodified soft acidic drink.

The protective effects of toothpaste against erosion by orange juice: studies in situ and in vitro.

OBJECTIVES: There has been a monumental increase in the consumption of soft drinks, fruit juices and sport drinks in the UK, the US, and many other countries. Previous investigations have demonstrated the erosive nature of these acidic soft drinks. The aim of this investigation was to determine the protective effects of an experimental fluoride-based toothpaste, containing sodium hexametaphosphate, against an erosive challenge on tooth enamel. METHODS: The erosion of enamel by orange juice compared the experimental toothpaste with a benchmark sodium fluoride paste and negative control, water, in a 15-day in situ model; and the same in an in vitro enamel erosion model. Flat, polished human enamel samples with a surface profile of +/-0.1mum, were exposed to the three regimens in the single blind, crossover clinical study mimicked in vitro. Depths of the resulting eroded areas were measured using a profilometer. RESULTS: There was significantly more erosive damage on the specimens exposed to the benchmark paste and water compared to the test paste in both the in situ and in vitro studies. CONCLUSIONS: The data provide further support for tooth brushing before meals. Results of this study further suggest the sodium hexametaphosphate containing paste could be used to provide significant erosion protection in susceptible individuals over that provided by conventional fluoride products.