An Experimental Review of Optical Coherence Tomography Systems for Noninvasive Assessment of Hard Dental Tissues.

Optical coherence tomography (OCT) is a noninvasive, high-resolution, cross-sectional imaging technique. To date, OCT has been demonstrated in several areas of dentistry, primarily using wavelengths around 1,300 nm, low numerical aperture (NA) imaging lenses, and detectors insensitive to the polarization of light. The objective of this study is to compare the performance of three commercially available OCT systems operating with alternative wavelengths, imaging lenses, and detectors for OCT imaging of dental enamel. Spectral-domain (SD) OCT systems with (i) 840 nm (Lumedica, OQ LabScope 1.0), (ii) 1,300 nm (Thorlabs, Tel320) center wavelengths, and (iii) a swept-source (SS) OCT system (Thorlabs OCS1300SS) centered at 1,325 nm with optional polarization-sensitive detection were used. Low NA (0.04) and high NA (0.15) imaging lenses were used with system (iii). Healthy in vivo and in vitrohuman enamel and eroded in vitro bovine enamel specimens were imaged. The Tel320 system achieved greater imaging depth than the OQ LabScope 1.0, on average imaging 2.6 times deeper into the tooth (n = 10). The low NA lens provided a larger field of view and depth of focus, while the high NA lens provided higher lateral resolution and greater contrast. Polarization-sensitive imaging eliminated birefringent banding artifacts that can appear in conventional OCT scans. In summary, this study illustrates the performance of three commercially available OCT systems, objective lenses, and imaging modes and how these can affect imaging depth, resolution, field of view, and contrast in enamel. Users investigating OCT for dental applications should consider these factors when selecting an OCT system for clinical or basic science studies.

Feasibility of a Real-Time Clinical Augmented Reality and Artificial Intelligence Framework for Pain Detection and Localization From the Brain.

BACKGROUND: For many years, clinicians have been seeking for objective pain assessment solutions via neuroimaging techniques, focusing on the brain to detect human pain. Unfortunately, most of those techniques are not applicable in the clinical environment or lack accuracy. OBJECTIVE: This study aimed to test the feasibility of a mobile neuroimaging-based clinical augmented reality (AR) and artificial intelligence (AI) framework, CLARAi, for objective pain detection and also localization direct from the patient's brain in real time. METHODS: Clinical dental pain was triggered in 21 patients by hypersensitive tooth stimulation with 20 consecutive descending cold stimulations (32°C-0°C). We used a portable optical neuroimaging technology, functional near-infrared spectroscopy, to gauge their cortical activity during evoked acute clinical pain. The data were decoded using a neural network (NN)-based AI algorithm to classify hemodynamic response data into pain and no-pain brain states in real time. We tested the performance of several networks (NN with 7 layers, 6 layers, 5 layers, 3 layers, recurrent NN, and long short-term memory network) upon reorganized data features on pain diction and localization in a simulated real-time environment. In addition, we also tested the feasibility of transmitting the neuroimaging data to an AR device, HoloLens, in the same simulated environment, allowing visualization of the ongoing cortical activity on a 3-dimensional brain template virtually plotted on the patients' head during clinical consult. RESULTS: The artificial neutral network (3-layer NN) achieved an optimal classification accuracy at 80.37% (126,000/156,680) for pain and no pain discrimination, with positive likelihood ratio (PLR) at 2.35. We further explored a 3-class localization task of left/right side pain and no-pain states, and convolutional NN-6 (6-layer NN) achieved highest classification accuracy at 74.23% (1040/1401) with PLR at 2.02. CONCLUSIONS: Additional studies are needed to optimize and validate our prototype CLARAi framework for other pains and neurologic disorders. However, we presented an innovative and feasible neuroimaging-based AR/AI concept that can potentially transform the human brain into an objective target to visualize and precisely measure and localize pain in real time where it is most needed: in the doctor's office. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/13594.

The elderly as a market--challenges to evidence.

OBJECTIVE: To review the role of the oral care industry in the oral health of elders and opportunities for partnership with other key stakeholders. BACKGROUND: The elder population is growing at a faster rate than any other segment of the population. This is coupled with a greater probability of maintaining the dentition into later life and an increase in complex restorative work. If an elder's situation changes, they are highly vulnerable to a rapid onset of oral disease that can be devastating and extremely difficult to address. MATERIALS AND METHODS: This manuscript reviews the role of the oral care industry in understanding this population as a market and the different approaches that might be used in promoting health. RESULTS: Two key market segments were identified, the vulnerable elders with high levels of chronic oral disease, systemic complications, medications and often inability to maintain good standards of oral hygiene and a wealthier, health and beauty conscious group with a keen interest in maintaining a healthy, aesthetically pleasing and functional dentition throughout their lives. CONCLUSIONS: It is likely that within current healthcare models, the oral care of elders will be unsustainable, with a smaller working population funding ever-increasing health care needs. 'Home care' combined with effective professional preventive and effective therapeutic options are essential. Partnerships between the oral care industry and oral care providers, to deliver education and engagement of care workers, medical practitioners, pharmacists and social services, are essential over the next few decades.

The Seattle Care Pathway for securing oral health in older patients.

There is a need for a structured, evidence based approach to care for older dental patients. The following article describes the development of the Seattle Care Pathway based upon a workshop held in 2013. An overview is provided on the key issues of older persons dental care including the demography shift, the concept of frailty, the need for effective prevention and treatment to be linked to levels of dependency and the need for a varied and well educated work force. The pathway is presented in tabular form and further illustrated by the examples in the form of clinical scenarios. The pathway is an evidence based, pragmatic approach to care designed to be globally applicable but flexible enough to be adapted for local needs and circumstances. Research will be required to evaluate the pathways application to this important group of patients.

The association between social deprivation and the prevalence and severity of dental caries and fluorosis in populations with and without water fluoridation.

BACKGROUND: To determine the association between social deprivation and the prevalence of caries (including caries lesions restricted to enamel) and enamel fluorosis in areas that are served by either fluoridated or non-fluoridated drinking water using clinical scoring, remote blinded, photographic scoring for caries and fluorosis. The study also aimed to explore the use of remote, blinded methodologies to minimize the effect of examiner bias. METHODS: Subjects were male and female lifetime residents aged 11-13 years. Clinical assessments of caries and fluorosis were performed on permanent teeth using ICDAS and blind scoring of standardized photographs of maxillary central incisors using TF Index (with cases for fluorosis defined as TF > 0). RESULTS: Data from 1783 subjects were available (910 Newcastle, 873 Manchester). Levels of material deprivation (Index of Multiple Deprivation) were comparable for both populations (Newcastle mean 35.22, range 2.77-78.85; Manchester mean 37.04, range 1.84-84.02). Subjects in the fluoridated population had significantly less caries experience than the non-fluoridated population when assessed by clinical scores or photographic scores across all quintiles of deprivation for white spot lesions: Newcastle mean DMFT 2.94 (clinical); 2.51 (photo), Manchester mean DMFT 4.48 (clinical); 3.44 (photo) and caries into dentine (Newcastle Mean DMFT 0.65 (clinical); 0.58 (photo), Manchester mean DMFT 1.07 (clinical); 0.98 (photo). The only exception being for the least deprived quintile for caries into dentine where there were no significant differences between the cities: Newcastle mean DMFT 0.38 (clinical); 0.36 (photo), Manchester mean DMFT 0.45 (clinical); 0.39 (photo). The odds ratio for white spot caries experience (or worse) in Manchester was 1.9 relative to Newcastle. The odds ratio for caries into dentine in Manchester was 1.8 relative to Newcastle. The odds ratio for developing fluorosis in Newcastle was 3.3 relative to Manchester. CONCLUSIONS: Water fluoridation appears to reduce the social class gradient between deprivation and caries experience when considering caries into dentine. However, this was associated with an increased risk of developing mild fluorosis. The use of intra-oral cameras and remote scoring of photographs for caries demonstrated good potential for blinded scoring.

Quantitative light fluorescence (QLF) and polarized white light (PWL) assessments of dental fluorosis in an epidemiological setting.

BACKGROUND: To determine if a novel dual camera imaging system employing both polarized white light (PWL) and quantitative light induced fluorescence imaging (QLF) is appropriate for measuring enamel fluorosis in an epidemiological setting. The use of remote and objective scoring systems is of importance in fluorosis assessments due to the potential risk of examiner bias using clinical methods. METHODS: Subjects were recruited from a panel previously characterized for fluorosis and caries to ensure a range of fluorosis presentation. A total of 164 children, aged 11 years (±1.3) participated following consent. Each child was examined using the novel imaging system, a traditional digital SLR camera, and clinically using the Dean's and Thylstrup and Fejerskov (TF) Indices on the upper central and lateral incisors. Polarized white light and SLR images were scored for both Dean's and TF indices by raters and fluorescence images were automatically scored using software. RESULTS: Data from 164 children were available with a good distribution of fluorosis severity. The automated software analysis of QLF images demonstrated significant correlations with the clinical examinations for both Dean's and TF index. Agreement (measured by weighted Kappa's) between examiners scoring clinically, from polarized photographs and from SLR images ranged from 0.56 to 0.92. CONCLUSIONS: The study suggests that the use of a digital imaging system to capture images for either automated software analysis, or remote assessment by raters is suitable for epidemiological work. The use of recorded images enables study archiving, assessment by multiple examiners, remote assessment and objectivity due to the blinding of subject status.

Adolescents' perceptions of the aesthetic impact of dental fluorosis vs. other dental conditions in areas with and without water fluoridation.

BACKGROUND: The use of fluorides for caries prevention is well established but is linked with an increased risk of dental fluorosis, some of which may be considered to be aesthetically objectionable. Patient opinion should be considered when determining impact on aesthetics. The aim of this study was to assess participant rating of dental aesthetics (from photographic images) of 11 to 13 year olds participating in an epidemiological caries and fluorosis survey in a fluoridated and a non-fluoridated community in Northern England. METHODS: Consented participants were invited to rank in order of preference (appearance) a collage of 10 computer generated images on a touch-screen laptop. The images comprised an assortment of presentations of teeth that included white teeth, a spectrum of developmental defects of enamel and dental caries. Data were captured directly and exported into SPSS for analysis. RESULTS: Data were available for 1553 participants. In general, there were no significant differences in the rank positions between the fluoridated and non-fluoridated communities, with the exception of teeth with caries and teeth with large demarcated opacities. Very white teeth had the highest rating in both localities. Overall, there was a trend for teeth with fluorosis to be ranked more favourably in the fluoridated community; for TF 1 and TF 2 this preference was significant (p < 0.001). CONCLUSIONS: The results of this study suggest teeth that are uniformly very white have the highest preference. The rankings suggest teeth with a fluorosis score of TF 1 may not be considered aesthetically objectionable to this population and age group. The image depicting a tooth with caries and the image with large demarcated opacities were deemed to be the least favoured. Participant preference of images depicting fluorosis falls with increasing severity of fluorosis.

Dental fluorosis in populations from Chiang Mai, Thailand with different fluoride exposures - paper 1: assessing fluorosis risk, predictors of fluorosis and the potential role of food preparation.

BACKGROUND: To determine the severity of dental fluorosis in selected populations in Chiang Mai, Thailand with different exposures to fluoride and to explore possible risk indicators for dental fluorosis. METHODS: Subjects were male and female lifetime residents aged 8-13 years. For each child the fluoride content of drinking and cooking water samples were assessed. Digital images were taken of the maxillary central incisors for later blind scoring for TF index (10% repeat scores). Interview data explored previous cooking and drinking water use, exposure to fluoride, infant feeding patterns and oral hygiene practices. RESULTS: Data from 560 subjects were available for analysis (298 M, 262 F). A weighted kappa of 0.80 was obtained for repeat photographic scores. The prevalence of fluorosis (TF 3+) for subjects consuming drinking and cooking water with a fluoride concentration of <0.9 ppm was 10.2%. For subjects consuming drinking and cooking water >0.9 ppm F the prevalence of fluorosis (TF 3+) rose to 37.3%. Drinking and cooking water at age 3, water used for infant formula and water used for preparing infant food all demonstrated an increase in fluorosis severity with increase in water fluoride level (p < 0.001). The probability estimate for the presentation of aesthetically significant fluorosis was 0.53 for exposure to high fluoride drinking (≥0.9 ppm) and cooking water (≥1.6 ppm). CONCLUSIONS: The consumption of drinking water with fluoride content >0.9 ppm and use of cooking water with fluoride content >1.6 ppm were associated with an increased risk of aesthetically significant dental fluorosis. Fluoride levels in the current drinking and cooking water sources were strongly correlated with fluorosis severity. Further work is needed to explore fluorosis risk in relation to total fluoride intake from all sources including food preparation.

Evaluating the use of fluorescent imaging for the quantification of dental fluorosis.

BACKGROUND: The quantification of fluorosis using fluorescence imaging (QLF) hardware and stain analysis software has been demonstrated in selected populations with good correlation between fluorescent image metrics and TF Index scores from photographs. The aim of this study was to evaluate the ability of QLF to quantify fluorosis in a population of subjects (aged 11-13) participating in an epidemiological caries and fluorosis survey in fluoridated and non-fluoridated communities in Northern England. METHODS: Fluorescent images of the maxillary incisors were captured together with standardized photographs were scored blind for fluorosis using the TF Index. Subjects were excluded from the analysis if there were restorations or caries on the maxillary central incisors. RESULTS: Data were available for 1774 subjects (n=905 Newcastle, n=869 Manchester). The data from the fluorescence method demonstrated a significant correlation with TF Index scores from photographs (Kendall's tau = 0.332 p<0.0001). However, a number of additional confounding factors such as the presence of extrinsic stain or increased enamel translucency on some subjects without fluorosis or at low levels of fluorosis severity had an adverse impact on tooth fluorescence and hence the outcome variable. This in conjunction with an uneven distribution of subjects across the range of fluorosis presentations may have resulted in the lower than anticipated correlations between the fluorescent imaging metrics and the photographic fluorosis scores. Nevertheless, the fluorescence imaging technique was able to discriminate between a fluoridated and non-fluoridated population (p<0.001). CONCLUSIONS: Despite confounding factors the fluorescence imaging system may provide a useful objective, blinded system for the assessment of enamel fluorosis when used adjunctively with photographic scoring.

Dental fluorosis in populations from Chiang Mai, Thailand with different fluoride exposures - paper 2: the ability of fluorescence imaging to detect differences in fluorosis prevalence and severity for different fluoride intakes from water.

BACKGROUND: To assess the ability of fluorescence imaging to detect a dose response relationship between fluorosis severity and different levels of fluoride in water supplies compared to remote photographic scoring in selected populations participating in an observational, epidemiological survey in Chiang Mai, Thailand. METHODS: Subjects were male and female lifetime residents aged 8-13 years. For each child the fluoride content of cooking water samples (CWS) was assessed to create categorical intervals of water fluoride concentration. Fluorescence images were taken of the maxillary central incisors and analyzed for dental fluorosis using two different software techniques. Output metrics for the fluorescence imaging techniques were compared to TF scores from blinded photographic scores obtained from the survey. RESULTS: Data from 553 subjects were available. Both software analysis techniques demonstrated significant correlations with the photographic scores. The metrics for area effected by fluorosis and the overall fluorescence loss had the strongest association with the photographic TF score (Spearman's rho 0.664 and 0.652 respectively). Both software techniques performed well for comparison of repeat fluorescence images with ICC values of 0.95 and 0.85 respectively. CONCLUSIONS: This study supports the potential use of fluorescence imaging for the objective quantification of dental fluorosis. Fluorescence imaging was able to discriminate between populations with different fluoride exposures on a comparable level to remote photographic scoring with acceptable levels of repeatability.

Evaluation of the sensitivity of a digital plaque imaging system on different tooth surfaces.

OBJECTIVE: The study aimed to test the sensitivity of digital plaque imaging in distinguishing the effectiveness of test and control mouthwashes for different groups of tooth surfaces. METHODS: The study was a double-blind, parallel, randomized, controlled clinical trial. Sixty subjects underwent scaling and polishing after recruitment, and attended their baseline examination after a washout phase of a minimum of seven days. They were then randomly assigned to one of two mouthwashes: 1) 0.05% CPC mouthwash; and 2) matching placebo mouthwash without CPC. Both groups were asked to use their assigned mouthwash and to refrain from any other oral hygiene measures for a period of eight days. At the baseline and day 8 visits, digital images of tooth surfaces were captured using Quantitative Light-induced Fluorescence (QLF) imaging, and plaque area as a percentage of the tooth surface was measured. Comparisons were carried out between the products for different groups of tooth surfaces. The data generated by the software were validated by a manual plaque outlining technique. RESULTS: Fifty-eight (58) subjects completed the study. More plaque was detected on the facial surfaces for the whole mouth (42.88% coverage for CPC and 46.45% for placebo) than the whole mouth lingual surfaces (7.23% coverage for CPC and 11.10% for placebo). Significant differences were observed between the products for the following areas: all tooth surfaces (p = 0.032), anterior lingual (p = 0.005), posterior lingual (p = 0.003), and whole mouth lingual (p = 0.001), whereas there were no differences between the products for anterior facial, anterior (facial & lingual), posterior facial, posterior (facial & lingual), and whole mouth facial. A strong correlation (R = 0.793, p < 0.001) was observed between the data (mean difference of percentage plaque coverage) generated by the analyzing program and that from the manual plaque outlining technique. CONCLUSION: The digital plaque imaging system was able to distinguish between the products when looking at the whole mouth. Digital imaging was better able to separate the groups when examining the lingual surfaces than facial.

The water fluoridation debate.

UNLABELLED: Water fluoridation schemes have been employed for over 50 years. Water fluoridation has been a source of continuous debate between those who advocate its use as a public health measure and those who oppose it. There have been no new fluoridation schemes in the U.K. for nearly 30 years owing to principally legislative, but also geographic, financial, and political reasons. However, in early 2008, the U.K. Secretary of State for Health promoted the use of water fluoridation schemes for areas in England with the highest rates of decay. This article, the third and final article of three, aims to discuss the arguments surrounding water fluoridation and its continued relevance as a public health measure. CLINICAL RELEVANCE: This article aims to provide an update for general practitioners for the background and the current status of the water fluoridation debate and to enable them to answer non-clinical questions raised by patients.

An automated assessment algorithm for micro-CT images of occlusal caries.

OBJECTIVES: To produce and test an algorithm to automatically quantify natural occlusal caries lesions in micro-computed tomography (micro-CT) scans of human teeth. METHODS: The algorithm presented divides the occlusal surface into regions of enamel and dentine by looking for sharp increases and decreases in radiopacity characteristic of step changes between materials. The accuracy of an automatic occlusal caries assessment based on these regions is assessed against serial histological assessment and manual examination of the same micro-CT images, using data from 68 previously scanned and sectioned teeth with varying levels of natural occlusal caries. RESULTS: Only three teeth were found to be free of caries by histology. The results of the automated analysis correlate well with histological assessment with a ρ of 0.80 (p < 0.001), and with manual CT assessment with a ρ of 0.85 (p < 0.001). The depth of dentine lesions correlated with histology with an intra-class correlation coefficient of 0.82 (p < 0.001; N = 45) and with manual assessment with an ICC of 0.93 (p < 0.001; N = 39). Micro-CT is found to generally underestimate caries compared to histological assessment. CONCLUSIONS: The algorithm presented can successfully segment micro-CT scans into occlusal enamel and dentine regions, and the results show that the depths of dentine caries lesions can be accurately and objectively measured automatically using micro-CT. However, if enamel caries is to be accurately assessed by a computer, better scans will be required than those used here.

Why fluoride?

UNLABELLED: Fluoride has been used in dentistry for over 100 years for the purpose of preventing dental caries. During this time there has been great debate over the mode of action, the optimum method of delivery, and the potential risks associated with its use. This, the first of three papers, will provide a summary of the history of the use of fluoride, the mode of action, benefits and different methods of delivery. It will also discuss the potential risk of dental fluorosis. CLINICAL RELEVANCE: This article aims to provide a background for general practitioners for the appropriate use of fluorides in dentistry, enable them to understand the wider significance of fluoride in dentistry and to be able to answer non-clinical questions raised by patients.

Water fluoridation as a public health measure.

UNLABELLED: Water fluoridation schemes have been used as dental public health measures for over 50 years. This second paper in a series of three aims to provide a background to the history of water fluoridation schemes and the evidence base that led to their implementation. The article will also discuss the processes and chemicals involved in fluoridation during water treatment. CLINICAL RELEVANCE: This article aims to provide a summary for general practitioners of the history and evidence base for water fluoridation, to enable them to understand the role of water fluoridation in caries prevention and to be able to answer non-clinical questions raised by patients.

Automatic detection and classification of dental fluorosis in vivo using white light and fluorescence imaging.

OBJECTIVES: To assess a novel method of automatic fluorosis detection and classification from white light and fluorescent images. METHODS: Dental images from 1,729 children living in two fluoridated and two non-fluoridated UK cities were utilised. A novel detection and classification algorithm was applied to each image and TF scores were obtained using thresholding criteria. These were compared to clinical reference standard images. Comparisons between reference and automated assessments were undertaken to record correct and incorrect classifications and the ability of the system to separate the fluoridated and non-fluoridated populations. RESULTS: The automated system performed well and was able to differentiate the two populations (P < 0.0001) to the same degree as the reference standard. When using the highest score from the clinical assessment the agreement between automated and clinical assessments was 0.56 (Kappa SE = 0.0160, p < 0.0001). CONCLUSIONS: Assessment of dental fluorosis is typically undertaken by clinical examiners in epidemiological studies. The training and calibration of such examiners is complex and time consuming and the assessments are subject to bias - frequently because of the examiner's awareness of the water fluoridation status of subjects. The use of remote scoring using photographs has been advocated but still requires trained examiners. This study has shown that image-processing methodologies applied to white light and fluorescent images could automatically score fluorosis and statistically separate fluoridated and non-fluoridated areas. The system requires further refinement to manage confounding factors such as the presence of non-fluoride opacities and tooth stain.

Digital epidemiology - Calibrating readers to score dental images remotely.

BACKGROUND: There is growing interest to use digital photographs in dental epidemiology. However, the reporting of procedures and metric-based performance outcomes from training to promote data quality prior to actual scoring of digital images has not been optimal. METHODS: A training study was undertaken to assess training methodology and to select a group of scorers to assess images for dental fluorosis captured during the 2013-2014 National Health and Nutrition Examination Survey (NHANES). Ten examiners and 2 reference examiners assessed dental fluorosis using the Deans Index (DI) and the Thylstrup-Fejerskov (TF) Index. Trainees were evaluated using 128 digital images of upper anterior central incisors at three different periods and with approximately 40 participants during two other periods. Scoring of all digital images was done using a secured, web-based system. RESULTS: When assessing for nominal fluorosis (apparent vs. non-apparent), the unweighted Kappa for DI ranged from 0.68 to 0.77 and when using an ordinal scale, the linear-weighted kappa for DI ranged from 0.43 to 0.69 during the final evaluation. When assessing for nominal fluorosis using TF, the unweighted Kappa ranged from 0.67 to 0.89 and when using an ordinal scale, the linear-weighted kappa for TF ranged from 0.61 to 0.77 during the final evaluation. No examiner improvement was observed when a clinical assessment feature was added during training to assess dental fluorosis using TF, results using DI was less clear. CONCLUSION: Providing examiners theoretical material and scoring criteria prior to training may be minimally sufficient to calibrate examiners to score digital photographs. There may be some benefit in providing an in-person training to discuss criteria and review previously scored images. Previous experience as a clinical examiner seems to provide a slight advantage at scoring photographs for DI, but minimizing the number of scorers does improve inter-examiner concordance for both DI and TF.

Vital tooth bleaching in dental practice: 1. Professional bleaching.

UNLABELLED: As dental health improves, with the concurrent drop in the provision of basic restorative care, patients are now asking their dentists to provide aesthetic treatments rather than the treatment of disease. Tooth bleaching is one such treatment that is frequently described in consumer magazines and television shows, driving consumer interest in this, apparently, benign therapy. This three-part series demonstrates the techniques that can be employed, within the dental practice or under the supervision of a clinician, those systems that can be bought by patients over the counter and, finally, a discussion of the biological effects of peroxide-containing solutions and the legal position on such products in the UK. In this section, we will describe the common methods by which teeth can be bleached, either by the clinician directly, or under his/her supervision by the use of'at home' kits. Efficacy and safety issues will be described. CLINICAL RELEVANCE: Clinicians should be able to discuss the merits, risks and likely success of a variety of bleaching treatments with their patients and, in doing so, assist in the process of obtaining informed consent.

Vital tooth bleaching in dental practice: 3. Biological, dental and legal issues.

UNLABELLED: The final section of this series examines both the evidence for the safety of external bleaching with hydrogen peroxide and related products and the legal position in the UK with regard to their sale and use in general dental practice. Potential side-effects are examined, including biological effects and dental effects, with a review of the current evidence. The EU Cosmetics and Medical Device Directive are both described and their impact on the provision of tooth bleaching in the UK is explained. The legal position in the UK renders the sale and supply of solutions containing >0.1% peroxide illegal, and practitioners must be aware of the underlying legislation and the basis upon which a prosecution may be pursued. CLINICAL RELEVANCE: Clinicians considering using hydrogen peroxide products must be aware of the safety issues surrounding their use and be able to explain to patients the nature of the risk and also the likelihood of any given patient experiencing them.

A pilot study of treatment of periodontal-endodontic lesions.

OBJECTIVE: A pilot study to evaluate a standardised treatment protocol for combined periodontal-endodontic lesions (involving staged endodontic and periodontal treatment). PARTICIPANTS: Nine patients with a diagnosis of a combined periodontal-endodontic lesion. METHODS: At baseline, root canal treatment (RCT) was performed by a standard protocol, and simple scaling/oral hygiene instruction provided. After one month, a standardised episode of non-surgical periodontal treatment was undertaken to address residual pocketing. Clinical measurements, including probing depths, attachment levels and bleeding on probing were recorded at baseline, month one and month three. Long-cone periapical radiographs taken using standardised projection geometry at baseline and month three were analysed for bone changes using digital subtraction radiography (DSR). RESULTS: During the study, one patient's affected tooth was extracted. From baseline to month three, there were statistically significant mean probing depth reductions (delta= 0.95mm, 95% CI= 0.20mm, 1.70mm; p= 0.02), mean attachment gains (delta= 1.13mm, 95% CI= 0.29mm, 1.96mm; p= 0.02) and reduction in mean bleeding on probing (delta= 29%, 95% CI= 10%, 49%; p= 0.01). DSR analysis revealed that between month 0 and month three, four teeth demonstrated bone gain, two teeth exhibited bone loss and two teeth showed no change. The mean bone change was in favour of bone gain but failed to achieve statistical significance (p>0.05). CONCLUSIONS: Within the limitations of this pilot study, treatment of periodontal-endodontic lesions by performing RCT prior to periodontal treatment was effective, resulting in improvements in clinical parameters together with alveolar bone gains in a majority of teeth.