The current referral patterns for temporomandibular joint disorders (TMD) in Greater Manchester

BACKGROUND

Temporomandibular joint disorders (TMD) affect up to 50% of the population. Chronic TMD may have a significant impact on patients' quality of life and is associated with a significant cost burden to health services.

AIMS

The aim of this study was to investigate the incidence of TMD in Greater Manchester and to determine the most appropriate setting for its management.

METHODS

Data were retrospectively collected on the demographics, symptoms and management provided to patients referred for TMD.

RESULTS

There were 789 referrals analysed; 616 to a Tertiary Centre and 173 to a District General Hospital (DGH). The most common reason for referral was pain (82%), followed by limitation in opening (55%) and clicks or sounds (44%). 27% of referrals were managed with a splint and 12% were provided with advice or a patient information leaflet prior to referral.

DISCUSSION

The effect of chronic pain on patients' quality of life and the cost burden of its management compels us to review current practices in referral and management of TMD. Barriers to provision of treatment in primary care may include a lack of training, remuneration or confidence. These may be overcome with the development of self-care plans for patients and a care pathway for practitioners.

CONCLUSION

Based on existing evidence, timely and conservative management of TMD should be encouraged in primary care, enabling better outcomes to be achieved for patients and the maintenance of the experience and skill level of specialist services in secondary care.

Protocol for a Randomised controlled trial to Evaluate the effectiveness and cost benefit of prescribing high dose FLuoride toothpaste in preventing and treating dEntal Caries in high-risk older adulTs (reflect trial)

BACKGROUND

Dental caries in the expanding elderly, predominantly-dentate population is an emerging public health concern. Elderly individuals with heavily restored dentitions represent a clinical challenge and significant financial burden for healthcare systems, especially when their physical and cognitive abilities are in decline. Prescription of higher concentration fluoride toothpaste to prevent caries in older populations is expanding in the UK, significantly increasing costs for the National Health Services (NHS) but the effectiveness and cost benefit of this intervention are uncertain. The Reflect trial will evaluate the effectiveness and cost benefit of General Dental Practitioner (GDP) prescribing of 5000 ppm fluoride toothpaste and usual care compared to usual care alone in individuals 50 years and over with high-risk of caries.

METHODS/DESIGN

A pragmatic, open-label, randomised controlled trial involving adults aged 50 years and above attending NHS dental practices identified by their dentist as having high risk of dental caries. Participants will be randomised to prescription of 5000 ppm fluoride toothpaste (frequency, amount and duration decided by GDP) and usual care only. 1200 participants will be recruited from approximately 60 dental practices in England, Scotland and Northern Ireland and followed up for 3 years. The primary outcome will be the proportion of participants receiving any dental treatment due to caries. Secondary outcomes will include coronal and root caries increments measured by independent, blinded examiners, patient reported quality of life measures, and economic outcomes; NHS and patient perspective costs, willingness to pay, net benefit (analysed over the trial follow-up period and modelled lifetime horizon). A parallel qualitative study will investigate GDPs' practises of and beliefs about prescribing the toothpaste and patients' beliefs and experiences of the toothpaste and perceived impacts on their oral health-related behaviours.

DISCUSSION

The Reflect trial will provide valuable information to patients, policy makers and clinicians on the costs and benefits of an expensive, but evidence-deficient caries prevention intervention delivered to older adults in general dental practice.

TRIAL REGISTRATION

ISRCTN: 2017-002402-13 registered 02/06/2017, first participant recruited 03/05/2018. Ethics Reference No: 17/NE/0329/233335. Funding Body: Health Technology Assessment funding stream of National Institute for Health Research. Funder number: HTA project 16/23/01. Trial Sponsor: Manchester University NHS Foundation Trust, Oxford Road, Manchester, M13 9WL. The Trial was prospectively registered.

Sugar before bed: a simple dietary risk factor for caries experience

Clinical care pathways have placed renewed emphasis on caries risk assessment and the ability to predict and prevent further disease. With diet considered a key factor in the development of caries, the level of caries risk posed by dietary habits, such as the frequency of intake and timing of free sugars is questioned.

OBJECTIVE

To identify reliable and simple dietary risk factors for caries experience.

RESEARCH DESIGN

A cross-sectional observational study of a convenience sample with data gained from clinical examinations, questionnaire and a 24 hour dietary-recall interview.

PARTICIPANTS

128 subjects aged 11-12 from comprehensive schools in Greater Manchester and Newcastle upon-Tyne, UK.

OUTCOME MEASURES

free sugars consumed between meals, before bed and total % of total free sugars consumed were assessed from dietary assessments led by a dietitian. D4-6MFT was generated with a caries threshold of ICDAS stage 4 from clinical examinations.

RESULTS

Analysis revealed no significant differences in caries experience when looking specifically at caries into dentine, referred to as the cavity group (split at D4-6MFT), between high and low deprivation, consumption of free sugars between meals and free sugars (%). The consumption of free sugars within the hour before bed revealed a statistically significant difference between the cavity/no cavity groups (p=0.002). Logistic regression analysis on the cavity/no cavity groups revealed an odds ratio of 2.4 (95%CI 1.3,4.4) for free sugars consumption before bedtime.

CONCLUSIONS

The study suggests that the consumption of free sugars before bedtime may be an important risk factor for adolescent caries into dentine experience.

Prevalence and severity of dental fluorosis in four English cities

Objective

To assess the prevalence and severity of dental fluorosis in four city-based populations using a robust photographic method with TF index reporting; and to record the aesthetic satisfaction scores of children in all four cities.

Basic research design

Cross sectional epidemiological survey (surveillance).

Participants

1,904 children aged 11-14 years, in four English cities.

Interventions

Two cities were served by community water fluoridation schemes supplying water at 1mg/l F. The other two cities did not have water fluoridation schemes and had low levels of fluoride naturally present.

Main outcome measures

The prevalence and severity of dental fluorosis. Scoring was undertaken using high quality digital images by a single calibrated examiner.

Results

Data suggest that the prevalence of fluorosis at levels greater than TF2 are broadly similar to previous studies (F 10%, NF 2%), with an apparent increase in the total number of TF1 cases across both fluoridated (41%) and non-fluoridated cities (32%) with a commensurate decrease in TF0 (F 39%, NF 63%). Data suggest that the proportion of children expressing dissatisfaction with the appearance of their teeth is the same in fluoridated and non-fluoridated communities although the reasons for this may differ.

Conclusions

The levels of fluorosis that might be considered of aesthetic concern are low and stable while the increase in TF1 may be due to an increase in self- and professionally-applied fluoride products or the increased sensitivity afforded by the digital imaging system. It is not however a public health problem or concern. Further monitoring appears justified.

Dentists' perspectives on caries-related treatment decisions

OBJECTIVE

To assess the impact of patient risk status on Colombian dentists' caries related treatment decisions for early to intermediate caries lesions (ICDAS code 2 to 4).

METHODS

A web-based questionnaire assessed dentists' views on the management of early/intermediate lesions. The questionnaire included questions on demographic characteristics, five clinical scenarios with randomised levels of caries risk, and two questions on different clinical and radiographic sets of images with different thresholds of caries.

RESULTS

Questionnaires were completed by 439 dentists. For the two scenarios describing occlusal lesions ICDAS code 2, dentists chose to provide a preventive option in 63% and 60% of the cases. For the approximal lesion ICDAS code 2, 81% of the dentists chose to restore. The main findings of the binary logistic regression analysis for the clinical scenarios suggest that for the ICDAS code 2 occlusal lesions, the odds of a high caries risk patient having restorations is higher than for a low caries risk patient. For the questions describing different clinical thresholds of caries, most dentists would restore at ICDAS code 2 (55%) and for the question showing different radiographic thresholds images, 65% of dentists would intervene operatively at the inner half of enamel. No significant differences with respect to risk were found for these questions with the logistic regression.

CONCLUSION

The results of this study indicate that Colombian dentists have not yet fully adopted non-invasive treatment for early caries lesions.

Quantitative light-induced fluorescence to measure enamel remineralization in vitro

The aim of this study was to compare the ability of quantitative light-induced fluorescence (QLF) and surface microhardness (SMH) to measure the remineralization of enamel subsurface lesions, using a pH-cycling model including treatment with 0-ppm, 550-ppm or 1,100-ppm sodium fluoride (NaF) dentifrices.

METHODS

Subsurface lesions were created in human enamel specimens (n = 36) and exposed to a remineralization pH-cycling model for 14 days. The pH-cycling model was performed in an automated system where specimens were subjected to a demineralizing solution for 20 min and treatment for 1 min and were then remineralized for 7 h 39 min, 3 times daily. The treatments consisted of 3 NaF, silica-containing dentifrices (0 ppm F; 550 ppm F; 1,100 ppm F). The outcome variables were: change from baseline in surface hardness and percentage change from baseline in fluorescence. An ANCOVA explored differences between different treatment groups (at the p < 0.05 level). Associations between QLF and SMH were evaluated using Spearman's correlation coefficient.

RESULTS

The percentage SMH changes were 14.9 ± 2.1%, 56.6 ± 9.6% and 103.9 ± 14.6% for the 0-, 550- and 1,100-ppm F dentifrices, respectively. The percentage fluorescence changes were 15.6 ± 7.1%, 59.8 ± 11.9% and 85 ± 13.2%, respectively. The differences between all pairwise comparisons were statistically significant for both methods (p = 0.001). QLF correlated with SMH (r = 0.67).

CONCLUSIONS

Both the SMH and QLF methods demonstrated a significant F dose response for toothpaste in this in vitro remineralization model, and both methods were able to distinguish treatments with different F levels.

Estimating the need for dental sedation: evaluating the threshold of the IOSN tool in an adult population

AIM

The aim of this study was, through a service evaluation, to assess the use of the IOSN tool in determining whether threshold values were appropriate for identification of IV sedation and general anaesthetic (GA) cases from a referral population.

METHODS

A total of 105 patients were taken from a dental minor oral surgery referral service within a north west primary care trust over the course of six months. The IOSN tool was completed to assess: treatment complexity, medical and behavioural factors and patient anxiety levels. Each patient was then followed through to treatment. The type of sedation modality they received was compared to their IOSN score previously calculated and these results evaluated.

RESULTS

The findings suggest that 94% of patients were treated within primary care by the MOS service, of which 58% received local anaesthetic (LA) alone and 42% were treated by LA with IV sedation. There was a general marked trend as the IOSN score increased so did the treatment modality from LA, through sedation to GA. Logistic regression using the components of the IOSN tool to predict sedation use indicated the IOSN predictors distinguished between those who required sedation and those who didn't (chi-square = 56.411, p <0.0001, df = 3) with treatment complexity (Exp B = 10.836, p <0.0001) and anxiety (Exp B = 4.319, p <0.0001) shown to be significant factors in determining sedation need.

CONCLUSIONS

The data collected have shown that there is a positive relationship between the IOSN score and the type of treatment modality the patient received, suggesting that the threshold values are correctly set. It is concluded that IOSN tool is a useful means of aiding the clinician in both assessing and referring patients for that sedation need.

The views of examiners on the use of intra-oral photographs to detect dental caries in epidemiological studies

AIM

The aim of the study was to obtain the views of examiners on their experience of using intra-oral photographs as a means of detecting caries in epidemiological studies compared to an established visual examination method.

METHOD

A focus group discussion was conducted with five examiners experienced in an established visual examination method after they had performed visual dental examinations of a sample of children as well as assessed intra-oral photographs of the same children.

RESULTS

The time taken by examiners to assess intraoral photographs becomes extended when compared to performing a visual examination. The ability to assess intra-oral photographs on a screen at a convenient time and place was considered advantageous. The examiners found it easier to make caries detection decisions on intra-oral photographs of primary teeth than permanent teeth. Adequate removal of debris and moisture control prior to obtaining the photographs were considered important.

CONCLUSION

The views of examiners in this study suggest that to improve the utility of photographic method, further research is needed to determine adequate drying methods for use in the field. Consideration should be given to a time-limited, standardised presentation of the photographs including the size and resolution. Specific training on caries detection from photographs is also required.

A clinical investigation using quantitative light-induced fluorescence (QLF) of the anticaries efficacy of a dentifrice containing 1.5% arginine and 1450 ppm fluoride as sodium monofluorophosphate

OBJECTIVE

The purpose of this study was to assess the ability of a new dentifrice containing arginine, an insoluble calcium compound, and fluoride to arrest or reverse naturally occurring buccal caries lesions measured using Quantitative Light-induced Fluorescence (QLF).

METHODS

Three study groups used dentifrices which contained 1) 1.5% arginine and 1450 ppm fluoride as sodium monofluorophosphate (experimental), 2) 1450 ppm fluoride as sodium monofluorophosphate (positive control), and 3) no fluoride (negative control). All three dentifrices were formulated in the same calcium base. The study participants were from three schools in the city of Chengdu, Sichuan Province, China. A total of 446 of 450 recruited subjects completed the study. Of these, 147 were in the experimental, 148 in the positive control, and 151 in the negative control groups. The initial age of the children was 10-12 years (mean 11.4 +/- 0.54); 47.5% were female.

RESULTS

Using QLF, assessments of buccal caries lesions were made at baseline and after three and six months of product use. For AQ, representing lesion volume, the baseline mean value for the three groups was 27.30, and at the three-month examination the mean values were 16.76, 19.25, and 25.89 for the experimental, positive, and negative control dentifrices, respectively. This represents improvements from baseline of 38.6%, 29.5%, and 5.2%. At six months, the deltaQ values for the three groups were 13.46, 18.47, and 24.18, representing improvements from baseline of 50.7%, 32.3%, and 11.4%. For all QLF metrics, deltaF (loss of fluorescence), area, and deltaQ, the differences between the negative control and both the experimental and positive control groups were statistically significant (p < or = 0.01). The differences between the experimental and positive control groups attained statistical significance for deltaQ (p < or = 0.003) at the six-month examination.

CONCLUSION

It is concluded that both of the fluoride-containing toothpastes are significantly better at arresting and reversing buccal caries lesions than the non-fluoride toothpaste. Furthermore, it is concluded that the new dentifrice containing arginine, an insoluble calcium compound, and fluoride provides significantly greater anticaries benefit than a dentifrice containing fluoride alone.

Letter from America: UK and US state-funded dental provision

OBJECTIVES

Current UK and US economic conditions have re-focussed attention on the need to deliver dental care with limited finance and resources. This raises hard questions determining which services will be offered and what they should achieve to satisfy public demands and needs. We consider impending dental health reforms in the US and UK within the context of contemporary experiences to identify issues and delivery goals for the two nations.

BACKGROUND

The paper provides a brief history and background of the development of social dental care models in the UK and US, highlighting some differences in state-funded delivery of dental care. SHIFTING DEMAND: From the 1950s, demand for dental treatment has increased and acquired a more complex composition growing from predominantly surgical and restorative treatment to encompass preventive care and cosmetic services. PRIORITISING CARE ACCORDING TO NEED: Despite improvements in general health and technology, inequalities in access and utilisation of dental care are still experienced, primarily by groups with low socio-economic status. DELIVERY: BALANCING RESOURCES, DEMAND AND NEED: In developing and delivering reform agendas, much can be learned from previous policy interventions. Pressures of cost, coverage, and capacity, besides demand versus need must be carefully considered and balanced to deliver quality service and value for users and taxpayers.

CONCLUSIONS

Ethical and moral consideration should be given to making services needs-driven to address high treatment requirements rather than the high care demands of the worried well. This challenge brings the additional political pressure of convincing many of the voters (and subsequent complainers) that their demands may be less important than the needs of others.

Children's views on the experience of a visual examination and intra-oral photographs to detect dental caries in epidemiological studies

AIM

To elicit children's views on the established visual examination method used for the epidemiological surveillance of dental caries and an experimental intra-oral photographic examination method.

METHOD

Focus group interviews were conducted with 5-year-olds (with the aid of a puppet) and 10/11-year-olds (without puppet) after experiencing both methods. Ten focus groups were conducted in each cohort.

RESULTS

The children's views on the methods related to the acceptability of their experience. The key factors affecting acceptability and preferences related to the combined effects of contextual factors prior to the examination and experiences during the examination. These included communication and children's expectations. These factors influenced the examination experience along with their feelings about the environment and the tactile sensation from instruments in the mouth. Most children preferred the experimental photographic method as a means of caries detection over the traditional visual examination. They also wanted feedback on their oral health and more communication on what was happening during the examination. CONCLUSION Appropriate communication, attention to the examination environment and handling of instruments can enhance the dental examination experience for children in the school setting. The children's preferences indicated that generally, the intra-oral camera was well received as a means of caries detection for epidemiological studies within the school setting. These results may have implications for seeking ethical approval and conducting epidemiological studies on children in the future.

Effect of post-brushing mouthwash solutions on salivary fluoride retention--study 2

OBJECTIVE

This study evaluated the effects of three post-brushing mouthwashes containing 0 ppm F, 225 ppm F, and 500 ppm F, respectively, on salivary fluoride retention after brushing with 1450 ppm fluoride (as NaF) toothpaste and rinsing with water immediately after brushing.

METHODS

In this three-phase, randomized, cross-over study, an ion-specific electrode was used to measure salivary F levels in thirty trial participants before brushing (Time 0), and after brushing, rinsing with water, and then rinsing with one of the three mouthwashes. Time points evaluated after brushing were one, three, five, 10, 20, 30, 45, and 60 minutes. For saliva sample collections, subjects were asked to pool saliva in their mouths for 10 seconds before spitting out into a container for each of the time points.

RESULTS

The AUC0-60 means for F in saliva were 554, 252, and 20 for the 500, 225, and 0 ppm F mouthwash groups, respectively. The 500 ppm F mouthwash resulted in a 2660% increase in total fluoride salivary retention over 60 minutes when compared with the 0 ppm F group, and a 120% increase when compared with the 225 ppm F group. A significant difference (p < 0.001) in the AUC0-60 means between the three groups was observed using analysis of variance (ANOVA). Paired t-tests also showed significant differences in the mean fluoride retention over 60 minutes for all three pair-wise group comparisons (p < 0.001).

CONCLUSION

Use of a fluoride mouthwash containing 225 ppm F or 500 ppm F produced a significant increase in salivary fluoride retention following brushing with a 1450 ppm F toothpaste and rinsing with water compared to rinsing without fluoride. The use of the 500 ppm F mouthwash may be of particular benefit to those at high caries risk.

Occlusal caries detection by using thermal imaging

OBJECTIVES

To explore the applicability of thermal changes associated with dehydration for the detection and quantification of early tooth decay on occlusal surfaces using infrared imaging.

METHODS

A total of 72 sites on 25 human teeth with various degrees of natural demineralisation have been used. Continuous evaporation of water inside the pores by pressurised air-drying is used to produce a thermodynamic response on the tooth surface. The temporal profile of the temperature will depend on the amount of water at each position and this is studied in relation to the degree of porosity and the lesion severity. The area enclosed by the time-temperature curve, DeltaQ, was then used for quantification of the lesion.

RESULTS

Maps of DeltaQ were obtained and histological examinations were performed for all teeth. A detection sensitivity of 77% and specificity of 87% for areas that are either sound or have a histological E1 lesion, 87% and 72% for areas that have either an E2 or EDJ lesion, and 58% and 83% for areas that have a lesion reaching the dentin was found using this method.

CONCLUSIONS

Thermal imaging shows the ability to discriminate, in vitro, between (a) either areas that are sound or with a lesion on the outer half of the enamel and (b) areas with a lesion extending to the middle of the enamel or deeper. However, variations of the temperature in an open mouth and humidity due to respiration can potentially challenge the ability of using this technique in vivo and this requires further investigation.

Assessment of Autofluorescence to Detect the Remineralization Capabilities of Sodium Fluoride, Monofluorophosphate and Non-Fluoride Dentifrices

The purpose of the study was to determine if longitudinal measurements of enamel autofluorescence (quantitative light-induced fluorescence, QLF) could detect differences in remineralization of early enamel caries on buccal surfaces of anterior teeth following supervised daily brushing with either sodium fluoride (NaF; 1,450 ppm F), sodium monofluorophosphate (MFP; 1,450 ppm F) dentifrices or a herbal, non-fluoride placebo dentifrice. The study was a pragmatic cluster-randomized controlled trial with schools as the unit of randomization. Twenty-one schools in Chengdu, China, comprised the clusters; 296 children with at least 1 visible white-spot lesion were examined using QLF at baseline and after 3 and 6 months. Each of the 21 clusters was randomly assigned 1 of the 3 dentifrices, and the children brushed under supervision once per day for 2 min. The primary outcome measure was deltaQ (product of fluorescence loss and area) at a 5% threshold after 6 months of product use. A multi-level model was fitted to the data at the site level, taking into account the hierarchical structure with baseline deltaQ, age and sex as covariates. After 3 months there was a significant difference between the MFP group and placebo (p = 0.02) and after 6 months between the NaF group (p = 0.002), MFP group (p < 0.001) and the placebo. QLF methodology could detect, within 3- and 6-month periods of supervised brushing, a difference in remineralization between fluoride-containing and non-fluoride-containing dentifrices. Typically lesions in all 3 treatment groups demonstrated improvement. Groups receiving fluoride experienced a more rapid and more substantial remineralization than those in the placebo group.

Reliability of quantitative laser fluorescence analysis of smooth surface lesions adjacent to the gingival tissues

The aim of this study was to determine the impact of analysis patch border inclusion or exclusion on the reliability of quantitative laser fluorescence (QLF) analyses of lesions close to the gingival margin. Ninety-three lesions on the maxillary anterior teeth were imaged using a fluorescent capturing system. All the lesions were located on the gingival third of the teeth. One examiner undertook two analyses of the images 1 week apart and another examiner undertook a single analysis. Analyses were undertaken using QLF 2.00 g with four patch borders. Each border was assessed as active or inactive. QLF metrics DeltaF, DeltaQ and area were exported. Kappa statistics were used to measure the agreement of border inclusion between all three analyses, and intra-class correlation coefficients (ICCs) were used to determine the intra- and inter-examiner reliability of the QLF metrics. Agreement on border exclusion was poor; with intra-examiner kappa of 0.48 and inter-examiner at 0.20. However, despite the inconsistencies in border exclusions the ICCs for each QLF metric were high; intra-examiner DeltaQ 0.91, DeltaF 0.80 and area 0.92; inter-examiner DeltaQ 0.86, DeltaF 0.68, area 0.88. Lesions adjacent to the gingival margin will often require a patch analysis border to be excluded in order to ensure a satisfactory reconstruction and thus accurate analysis. The decision to include or exclude a border and, if excluded, which border to select appears to be highly variable between examiners. Nevertheless, the QLF metrics appear to be robust as demonstrated by the high ICCs noted in this study.

Comparison of paired visual assessment and software analyses of changes in caries status over 6 months from fluorescence images

Images captured using light-induced fluorescence systems are generally analysed using proprietary software. The purpose of this study was to determine if such images could be scored visually and to compare these data with those metrics produced by the software. A total of 171 lesions were selected from a pool of images to provide a range of lesions which were reported as having remained static, increased or decreased in fluorescence using the QLF analysis software. The baseline and 6-month images were then assessed side by side on a computer screen by 10 examiners who were asked to rate the lesions to determine if the lesion had become better or worse, or had stayed the same. There was generally poor correlation between clinical visual image assessments and all QLF analysis outcomes for all examiners. The agreement amongst the visual image assessments for the 10 examiners compared to the average score ranged from kappa 0.22 to 0.59 and the rank correlations from -0.01 to 0.73. This study suggests that the visual assessment of lesion images by the examiners in this study was based upon different characteristics of lesion change than those utilised by the QLF analysis software. A clearer understanding of lesion characteristics that are indicative of positive and negative changes may be required before this technology can be exploited to its full potential.

Quantification of dental fluorosis using fluorescence imaging

Fluorescence imaging hardware and software have been recently employed to assess demineralization due to early dental caries. Dental fluorosis also presents as diffuse surface hypomineralization of enamel and in principle similar measurement methods might be applicable to both. The caries analysis system requires the user to select an area of sound enamel around the lesion so that the affected surface can be reconstructed and the lesion subtracted. Whereas early caries presents as discrete isolated lesions fluorosis is characterized by diffuse opacities covering most of the tooth. Consequently it is difficult to use commercial QLF software for the assessment of fluorosis, as there is typically no sound area of enamel to use for reconstruction. This study describes a fluorescent imaging device capable of recording digital images of the anterior teeth and also software that is able to objectively measure fluorosis area and severity. A convenience sample of 26 subjects with a range of fluorosis from TF scores 0-3 took part in the study. The upper left central incisor of these subjects was scored for fluorosis using the TF index, photographed using a conventional digital camera and imaged using the fluorescence imaging device. The TF index was then used to visually score the digital photographs and the fluorescence images. The data from the fluorescence method demonstrated a strong correlation with TF scores from fluorescence images (Kendall's tau = 0.862). The fluorescence imaging method shows promise as an objective, potentially blinded system for the longitudinal assessment of enamel fluorosis in vivo.

Effect of whitening gels on the surface roughness of restorative materials in situ

Peroxide gels are effective in changing tooth colour but their effect on restorative materials has been poorly studied. The purpose of this investigation was to assess the impact of a commercially available whitening gel containing hydrogen peroxide and a sodium percarbonate formulation on the surface of restorative materials. A total of 12 subjects participated in a double-blinded crossover study. Each wore an intra-oral appliance containing five bovine enamel blocks restored with amalgam, posterior composite, microfilled composite, glass ionomer cement and porcelain. Appliances were worn continuously for 14 days and whitening products were applied twice daily. After 14 days the appliances were removed and values for roughness (R(a)) were obtained using atomic force microscopy. Mean values of R(a) were assessed between baseline and 14 days, and although minor variations were seen, there were no statistically significant differences detected for any material or any whitening product.

The judicial view of bitemarks within the United States Criminal Justice System

When examining most traditional sciences a thorough review of the relevant primary literature is usually sufficient to provide the investigator with a sound insight into the discipline. Forensic science differs in this regard, as it is presented in two main arenas: the peer-reviewed forensic journals and the Courts of Law where testimony is proffered. Because of this duality of scientific assessment the following legal review is presented. The review analysed Appellate Court rulings from the United States and identified trends of objections to bitemark testimony. Nine major trends were identified within the cases assessed: bitemark evidence not sufficiently reliable or accepted, arguments regarding the uniqueness of the human dentition, constitutional arguments, inflammatory photographs, inaccuracy of techniques and errors in protocol, use of historical bitemarks and previous biting behavior, funds for defence witnesses and objections pertaining to witness credibility.

The microbiological origin of fluorescence observed in plaque on dentures during QLF analysis

The aim of this study was to determine the microbiological origin of plaque fluorescence observed during quantitative light-induced fluorescence (QLF) analysis. Plaque was sampled from dentures, because of easy accessibility and the homogeneous background provided by the denture tooth during imaging, and the acknowledged comparability to occlusal plaque. Forty removable poly(methyl methacrylate) dentures were screened for the presence of fluorescent plaque deposits during QLF analysis. Dentures were photographed, QLF images were recorded and samples of fluorescent plaque were taken. Plaque samples were cultured on fastidious anaerobe agar, Wilkins Chalgren agar and Sabourauds dextrose agar. Plates were screened under QLF and fluorescent colonies were subcultured and identified. Areas of red, orange and green fluorescence were detected on the fitting and non-fitting surfaces of dentures. The red and orange fluorescing species were Prevotella melaninogenica, Actinomyces israelii and Candida albicans, which are generally acknowledged to be secondary colonisers, present in more mature plaque. Green fluorescence was observed in streptococcal species (early colonisers) and Fusobacterium nucleatum (important organism in plaque development). Non-fluorescent colonies were also cultured. Plaque which accumulates on susceptible surfaces tends to be associated with caries, but it may be its maturity, rather than the presence of cariogenic streptococci, that is more likely to provide a microbiological link between red fluorescence and caries.

The Effects of Illumination and Focal Distance on Light-Induced Fluorescence Images in vitro

When using quantitative light-induced fluorescence a number of factors can influence illumination level. The purpose of this study was to investigate, using a high-resolution camera and fibre-optic light source, the impact of illumination level and focal distance on common quantitative light-induced fluorescence outcomes. Twenty-four extracted teeth were examined using 6 illumination levels and 4 focal distances. Analysis was conducted using multiple linear regression models fitted to log DeltaQ, log DeltaF and log area with clustering of teeth and robust standard errors. Separate models were used for the different light and focal levels. The regression coefficients were significant for both DeltaQ and DeltaF but not area. Despite the significant regressions the actual effect was very small, and unlikely to confound clinical trial or practice results.

The effect of video repositioning on the reliability of light-induced fluorescence imaging: an in vivo study

The ability to monitor longitudinally the development, arrest or resolution of early demineralised lesions is one strength of quantitative light-induced fluorescence (QLF). When taking sequential images of an individual's teeth for monitoring it has been suggested that the subsequent images should be taken from the same position the baseline image. To assist in this process, video repositioning software is available that enables automatic capture of images once the system identifies that they are similar enough to the baseline comparator. The purpose of this study was to determine if the use of such software-assisted capture improves the reliability of subsequent QLF analysis. 20 subjects had 34 surfaces (buccal and occlusal) imaged by 2 examiners at baseline, and again 1 week later using both manual and software-assisted (VidRep) systems. Analysis of the three key reportable values for QLF (DeltaF, lesion area, DeltaQ) suggested that there is no significant improvement in reliability using VidRep although VidRep demonstrates additional advantages above and beyond image geometry, relating to the speed of subsequent image analysis.

The effect of bleaching on enamel susceptibility to acid erosion and demineralisation

INTRODUCTION

The purpose of this in vitro study was to determine if enamel that had been bleached by carbamide (urea) peroxide gel (CPG) was at increased risk of either acid erosion or demineralisation (early caries) than un-bleached enamel.

METHODS

Human incisors were employed. The samples were randomly assigned to one of 4 groups; a) 10% CPG, b) 16% CPG, c) 22% CPG and d) 10% CPG with xylitol, fluoride and potassium. Each specimen was moistened with saliva and the appropriate formulation placed for 2 hours for a total of 40 hours of exposure. In order to ensure that bleaching had taken place, tooth shades were monitored using the Shade-Eye device. Following the bleaching process, one half of the specimen was subjected to an erosive challenge, the other to a demineralisation system with one half of each sub-sample retained as a non-bleached control. Samples were assessed longitudinally with quantitative light-induced fluorescence (QLF) and at the conclusion of the study with transverse micro-radiography (TMR).

RESULTS

Erosion was detected in all samples (DeltaQ 126+/-23.4), in both bleached and non-bleached areas. There was no statistical difference between the bleached and non-bleached areas either within the treatment groups or between them. Caries-like lesions were detected on all samples; TMR revealed sub-surface lesions on all teeth and QLF data supported this (DeltaQ 89+/-18.9). Following statistical analysis there were no differences detected between the bleached and non-bleached areas, nor between the different concentrations of the bleaching solution.

CONCLUSION

These results suggest that tooth bleaching with carbamide (urea) peroxide (using commercially available concentrations) does not increase the susceptibility of enamel to acid erosion or caries.

The use of in situ models and QLF for the study of coronal caries

OBJECTIVES

The purpose of the paper is to review aspects of the systems available to model the caries process in enamel.

METHODS

The in situ model developed in Liverpool, and the new method of quantifying mineral loss, Quantitative Light-induced Fluorescence (QLF), are described. QLF is a powerful new diagnostic tool which can be used to measure demineralisation and remineralisation in tooth surfaces in vivo; studies to optimise, validate and use QLF in different clinical situations are described.

RESULTS

Examples of the use of in situ models show that they are particularly valuable for monitoring de and remineralisation of artificial lesions in relation to product testing as alternatives to clinical trials, and present significant advances over in vitro methods. Quantification of mineral loss by Transverse Microradiography (TMR) as in the traditional Liverpool model has produced much valuable information, but the destructive nature of the method limits experimental design, and removes the system from the clinical situation. As a possible alternative, QLF has been validated and optimised. Longitudinal measures can be made on the same surface, and examples of its use are for monitoring recurrent caries and demineralisation around orthodontic brackets.

CONCLUSIONS

While current in situ models provide a major advance over earlier caries models, measurement of de and remineralisation by destructive methods such as transverse microradiography limits the design of experimental investigations. QLF offers significant time saving, reduces the cost of clinical studies, and because the measurements can be carried out longitudinally in vivo, can remove the need for intra-oral appliances carrying experimental tissues.

Quantification of dental plaque in the research environment

OBJECTIVES

To review the established and novel methods of plaque quantification employed in dental research, including a discussion of their merits and to present a new method of planimetrically measuring plaque using light induced fluorescence.

METHOD

Quantitative light-fluorescence (QLF) images were acquired from the buccal surfaces of an individual who had refrained from oral hygiene both with and without traditional plaque disclosure. Digital photographs were also taken. Images were analysed using a novel method and a percentage plaque index produced.

RESULTS

Traditional plaque indices are problematic due to their integral nature and their failure to detect small, but potentially clinically relevant changes in plaque area. The use of a fluorescent technique demonstrated good reliability although there was no correlation between red fluorescent plaque and total disclosed plaque suggesting that the auto-fluorescing plaque is not a good measure of total plaque volume.

CONCLUSIONS

The use of planimetric techniques can increase the power of plaque studies, potentially reducing the number of subjects and time required to separate therapies or products. Fluorescent methods of quantification have potential as they enable clear separation of the plaque covered and non-covered tooth surfaces.

A study to assess the efficacy of a new detergent free, whitening dentifrice in vivo using QLF planimetric analysis

OBJECTIVE

To determine the effects of a detergent-free, whitening dentifrice using an in vivo plaque regrowth model with the novel application of QLF as a planimetric analysis tool.

METHOD

A total of 20 subjects took part in a double blind, single-centre, crossover study in which slurry rinses were the only form of plaque control over a 5-day period. Following a washout and prophylaxis the subjects used 2 daily rinses in the absence of all other plaque control methods. Subjects returned to the clinic on the afternoon of day 5 when plaque was disclosed and assessed by the plaque index and area using both a photographic and novel fluorescent planimetric technique. A further 9-day washout was carried out and the rinse period repeated to ensure that each subject had used both experimental and comparator slurries.

RESULTS

Twenty subjects completed the trial. The test product showed a significant inhibition of plaque re-growth (16.9%) compared with a fluoride-matched comparator using the Turesky index (P < 0.0001), the photographic planimetric technique (17.5%) (P < 0.0001) and the novel QLF technique (18.4%) (P < 0.0001).

CONCLUSION

The results confirm that plaque inhibition capability of a detergent-free whitening dentifrice is at least as effective as a fluoride matched comparator. QLF is a promising tool for disclosed plaque quantification.

The validation of Quantitative light-induced fluorescence to quantify acid erosion of human enamel

OBJECTIVE

The purpose of this study was to validate the Quantitative light-induced fluorescence (QLF) device against transverse microradiography (TMR) with regard to the quantification of enamel erosion in vitro.

DESIGN

Longitudinal in vitro.

METHODS

Thirty previously extracted, caries free, human premolars were selected and prepared by gentle pumicing and coating in an acid-resistant nail-varnish save for an exposed window on the buccal surface. QLF baseline images were taken and the teeth then exposed to an erosive solution, 0.1% citric acid (pH 2.74). Teeth were removed at 30min intervals, air-dried and QLF images taken. At this time one tooth was randomly selected, removed from solution and sectioned through the lesion at three sites. The polished sample (100microm) was subjected to TMR and analysed for erosive mineral loss using proprietary software, with the DeltaZ values noted. QLF images were analysed by a blinded examiner with DeltaF and DeltaQ values recorded. Data were entered into SPSS and the correlation between the DeltaZ and DeltaF, and DeltaZ and DeltaQ values calculated.

RESULTS

A wide range of erosive lesions was produced, with a steady increase in both DeltaZ and DeltaF over time; DeltaZ (24.0 (S.D. 1.2)-6114.3 (S.D. 1177.57)); DeltaF (1.8-11.2), DeltaQ (2.5-202.6). The results were scatter plotted and a regression line calculated. A positive correlation between DeltaZ and DeltaF of 0.91 was found, and for DeltaZ and DeltaQ; 0.87.

CONCLUSIONS

The ability for QLF to detect and longitudinally monitor in vitro erosion has been shown. The strong positive correlation of DeltaF with DeltaZ suggests that percentage fluorescence loss as measured by QLF could be of great value in the development of a non-destructive, longitudinal tool for use in vitro, in situ and possibly in vivo.

The effect of dehydration on quantitative light-induced fluorescence analysis of early enamel demineralization

The purpose of this study was to determine the effect of hydration [distilled water (DH2O) and saliva] on lesions of varying severity and determine an optimal drying method to obtain reliable quantitative light-induced fluorescence (QLF) readings. Ten previously extracted molars were placed into a demineralizing solution for 7, 14 and 21 days. Between each demineralizing cycle the teeth were removed. To test for in vitro reliability the teeth were rinsed in DH2O for 1 min and then QLF images were taken every 10 s (control cycle with no drying employed - bench drying only). This was repeated following (i). compressed air drying for 30 s or 15 s and (ii). 30 s cotton wool roll application (CWR). To test for in vivo reliability the experiment was repeated using whole human saliva in place of DH2O. Control groups demonstrated the effect of hydration on QLF reliability; at 7 days reliable results were obtained after 370.4 s (DH2O) and 432.3 s (saliva). Air drying of both DH2O and saliva-rinsed teeth reduced reliability time to 2.1 (+/-6.0) and 3.2 s (+/-7.6), respectively. Cotton wool roll application produced reliable results in 89 s with DH2O and 110 s with saliva. As lesion severity increased [14 days mean deltaQ 115 (+/-90.2), 21 days mean deltaQ 168.0 (+/-120.7)] time to reach reliability significantly increased under control drying and CWR (P > 0.05). Time taken for compressed air-dried teeth to produce reliable results was not significantly different across the groups. Compressed air-drying for 15 s produces reliable results with both DH2O and saliva-hydrated lesions. Future in vivo experiments will be required to determine if the air-drying can be reduced further in a clinical situation.

The use of fluorescein-enhanced quantitative light-induced fluorescence to monitor de- and re-mineralization of in vitro root caries

The use of fluorescein-enhanced quantitative light-induced fluorescence (QLF) in the detection of in vitro root caries demineralization and reminerlization was investigated. Fourteen previously extracted human premolar roots were selected and determined to be caries-free. Cementum was removed and nail varnish applied leaving an exposed window. Positive and negative controls were selected. During a demineralizing regimen, roots were removed at regular intervals (12, 48, 72 and 120 h) and immersed in sodium fluorescein (0.2 mg L(-1)). Following gentle rinsing, each root was examined using QLF before being returned to the demineralizing solution. Following 120 h, each tooth was sectioned through the lesion and one-half retained for transverse micro radiography (TMR) analysis. The remaining half were subjected to a remineralizing regimen undergoing the same fluorescein and QLF examinations at 7, 28 and 36 days. Results showed that QLF effectively monitored demineralization/remineralization of root dentine as represented by fluorescein penetration. TMR analysis showed good correlations with QLF (DeltaZ/DeltaQ) after demineralization (r = 0.89) and remineralization (r = 0.84). The technique could represent an in vivo method for root caries detection and classification.

A web-based survey of odontologist's opinions concerning bitemark analyses

Within the field of forensic dentistry, the detection, collection, and analysis of bitemarks remains one of the most contentious areas. Attempts at the production of consensus documents have produced documents such as the ABFO's Guidelines for Bitemark Evidence Collection. Despite this, the range of differing analysis techniques, allied with a varied opinion base on the robustness of bitemark conclusions has led to polarized views within the profession. The purpose of this study was to survey forensic dentists to obtain their views on a number of crucial components of bitemark theory and contentious areas within the discipline. Using a web-based survey, 14 questions were asked of respondents. Seventy-two odontologists completed the survey, with 38% being of Diplomate status, 10% had completed 20 or more bitemark cases, and 20% between 10 and 20 cases, 91% of respondents believed that the human dentition was unique, with 78% believing that this uniqueness could be represented on human skin during the biting process. Seventy percent believed that they could positively identify an individual from a bitemark, and 22% stated that the statistical tool, the product rule, should be applied to bitemark conclusions. Over half of the odontologists used overlays for bitemark analysis. with a digital method of production the most popular. The implications of these and other findings are discussed.

The use of dental aging techniques in forensic odontological practice

Many studies have been published describing numerous techniques to determine the aging of individuals from dental tissues. However, few case reports demonstrate how such techniques can be employed by the forensic odontologist undertaking casework. Indeed, many of the techniques are highly complex and utilize equipment not generally available to odontologists outside of the university or hospital systems. This paper describes five cases where dental aging was used for identification in the absence of materials for any other techniques. In each case the Bang and Ramm method was employed using sectioned teeth. Teeth were sectioned, photographed, and scaled in image analysis software. Bang and Ramm equations were employed, and in each case an age was derived. The estimated age was supplied to the coroner, who was able to use the information to positively identify five individuals for whom no other identification system was feasible.

The erosive potential of commercially available mouthrinses on enamel as measured by Quantitative Light-induced Fluorescence (QLF)

DESIGN

Longitudinal in vitro.

METHODS

Previously extracted, caries free, human premolars were selected and prepared by gentle pumicing and coating in an acid-resistant nail-varnish save for an exposed enamel window on the buccal surface. Each was assigned to one of eight groups (six per group, 10 in positive control); positive control (citric acid, pH 2.7, F(-) 0 ppm), negative control (pH 7.0, F(-) 0 ppm) Listerine (pH 3.87, F(-) 0.021 ppm), Tesco Value (pH 6.05, F(-) 289.00 ppm), Tesco Total Care (pH 6.20, F(-) 313.84 ppm), Sainsbury's (pH 6.15, F(-) 365.75 ppm), Sensodyne (pH 6.12, F(-) 285.30 ppm) and Corsodyl (pH 5.65, F(-) 0 ppm). The titratable acid values (TAV) for each rinse were established using volume (ml) of 0.1 M NaOH to achieve pH 7. Fluoride values were obtained by ion selective electrode. The solutions were kept at 37 degrees C and gently agitated. Teeth were removed at hourly intervals for 15 h, air-dried and subjected to Quantitative Light-induced Fluorescence (QLF) examination by a blinded examiner and DeltaQ values recorded. At the conclusion of the study each of the positive control teeth and one from each other group were sectioned through the eroded lesion, ground and polished to 100 micrometers and subjected to transverse microradiography and DeltaZ recorded for validation.

RESULTS

TAVs were: Listerine 2.45 L > Sainsbury's 0.35 ml >Tesco Total Care 0.14 ml > Tesco Value 0.08 ml > Corsodyl 0.10 ml >Sensodyne 0.9 ml. DeltaQ increased over time for the positive control, (0 h 0.2, 10 h 95.2, 15 h 152.3). Negative controls remained stable. The increase in DeltaQ for each rinse after 15 h was Listerine (9.3(+/-7.2)), Corsodyl (1.5(+/-1.2)), Tesco Value (1.8(+/-1.2)), Tesco Total Care (1.4(+/-1.1)), Sainsbury's (3.4(+/-2.2)), Sensodyne (0.9(+/-1.6)). TMR confirmed the presence/absence of erosive lesions.

CONCLUSIONS

QLF effectively monitored erosion in the positive controls and lack of erosion in the NC. Only one mouthrinse (Listerine) caused any erosion compared to the negative control, but this was only significant after 14 h of continuous use.

Detection of in vitro demineralization adjacent to restorations using quantitative light induced fluorescence (QLF)

AIM

Quantitative light-induced fluorescence (QLF) is a technique for the detection, quantification, and longitudinal monitoring of early carious lesions. The technique is non-destructive and can be used in vivo. Using the natural fluorescence of teeth, and the loss of such fluorescence in demineralized enamel, QLF is a repeatable and valid optical caries monitor. Previously used in smooth and occlusal surfaces, the purpose of this pilot study was to determine if QLF could detect, and longitudinally monitor, demineralization adjacent to a range of restorative materials.

METHODS

Fifteen previously extracted lower third molars were selected based upon the lack of any visible demineralization. A single burr hole was placed on the buccal surface and the cavity restored with amalgam, composite, compomer, glass ionomer or a temporary filling material. The buccal surface was then coated in an acid resistant nail varnish leaving an exposed area around the restoration and also a similar sized control region. The teeth had QLF images taken at baseline and were then subjected to a demineralizing buffer, further QLF images were subsequently taken at 72 and 144 h. Transverse microradiography was used to confirm the presence of early, subsurface lesions at the completion of the cycle (144 h). QLF images were analyzed by a single blinded examiner and values for change in radiance fluorescence were computed. These values were recorded as loss of radiance fluorescence loss integrated over area of lesion and expressed as DeltaQ.

RESULTS

The appearance of each material under QLF and the change in fluorescence is described. Amalgam, glass ionomer and the temporary material all exhibited reduced fluorescence, while composite and compomer showed increased fluorescence, when compared with surrounding enamel. There was no change in fluorescence of the materials when subjected to experimental demineralizing conditions. Readings at 72 and 144 h demonstrated demineralization adjacent to the restorations and at the exposed control. Significant differences were detected between baseline, 72 and 144 h using ANOVA on all restorations with the exception of compomer where significance was noted between baseline and 144 h, p>0.05.

CONCLUSIONS

This pilot study has demonstrated the ability for QLF to detect and monitor secondary caries. Analysis techniques should be based upon the subtraction of baseline DeltaQ scores from subsequent images. Further research is required to assess the ability of QLF to detect secondary lesions in vivo.

A study to assess the effects of a new detergent-free, olive oil formulation dentifrice in vitro and in vivo

OBJECTIVE

To determine the effects of a detergent-free dentifrice containing olive oil using in vitro microbiological tests and an in vivo plaque re-growth model.

METHOD

A total of 20 subjects took part in a double blind, single-centre, crossover study in which slurry rinses were the only form of plaque control over a 5-day period. Following a washout and prophylaxis the subjects used 2x daily rinses in the absence of all other plaque control methods. Subjects returned to the clinic on the afternoon of day 5 when plaque was disclosed and assessed by plaque index and area. A further 9-day washout was carried out and the rinse period repeated to ensure that each subject had used both experimental and control slurries. In vitro microbiological experiments were conducted to examine the effects of olive oil alone and in the new dentifrice on bacterial growth and adhesion.

RESULTS

20 subjects completed the trial. The olive oil product showed a significant inhibition of plaque re-growth (17.2%) compared with a fluoride-matched control using the Turesky index (p<0.0001) and also using the planimetric technique (22.0%) (p<0.0001). Significant decreases in bacterial growth and adhesion (measured as total viable count) were detected in the presence of olive oil and the new dentifrice.

CONCLUSION

The results suggest that the experimental olive oil containing paste has potential value in the inhibition of plaque.

The in vitro detection of early enamel de- and re-mineralization adjacent to bonded orthodontic cleats using quantitative light-induced fluorescence

The purpose of this study was to determine whether quantitative light-induced fluorescence (QLF) could detect very early demineralization and remineralization longitudinally adjacent to orthodontic components in an in vitro model. Extracted human premolars (n = 13) were sectioned sagittally to produce two equal halves and an orthodontic cleat was bonded to the buccal surface of each tooth. Transparent nail varnish was placed over the remaining surface, leaving exposed enamel windows adjacent to the cleat on the coronal and gingival aspects. Each half-tooth was placed into the lid of an Eppendorf tube and randomly assigned to either control (distilled water) or experimental (lactic acid demineralizing buffer, pH 4.5) regimes. Digital photographs and QLF baseline images were taken. The tubes were mounted into a rotating holder and left for 24 hours. QLF and digital photographs were taken, the solutions refreshed and the teeth returned. This was continued every 48 hours for 288 hours. At this time the lactic acid buffer was replaced with a remineralizing solution (artificial saliva, fluoride, calcium) and the experiment continued with weekly examinations. QLF images were analysed and deltaQ at the 5 per cent threshold recorded. Analysis of the QLF images showed that both demineralization and remineralization were identified and monitored. Statistical differences between each of the timed examinations were found (P < 0.05). Analysis of the photographs demonstrated that QLF detected subclinical lesions. This initial pilot study has demonstrated the potential for QLF to longitudinally monitor de- and re-mineralization of enamel adjacent to orthodontic cleats in vitro.

The intra- and inter-examiner reliability of quantitative light-induced fluorescence (QLF) analyses

OBJECTIVE

To assess the reliability of the analysis stage of quantitative light-induced fluorescence (QLF). The QLF analysis involves subjective input from the user and this study examines the influence of this on the reproducibility of the QLF data.

METHOD

QLF images were taken of 20 human molar teeth that had been previously subjected to a demineralizing solution (phosphoric acid 37%) to create artificial white spot lesions on their buccal surfaces. Following examination of the images, 16 were chosen to represent a range of lesion size and severity. Three copies were made of the images and each was allocated a different filename. 10 examiners in three centres were asked to analyse each of the 16 images on three occasions, with at least seven days between each attempt. Simple instructions describing the analysis procedure were supplied and examiners were asked to adhere to these directions. Examiners were asked to rate each of the 16 teeth on their first attempt both quantitatively (5 point scale) and qualitatively in terms of difficulty of analysis. Data reported were the delta Q at 5% threshold for each tooth on each of three attempts.

RESULTS

Using ANOVA and paired t-tests to detect statistical differences, the three attempts of each examiner were used to determine intra-examiner reliability. Only one examiner (a novice at the technique) demonstrated differences between all three attempts and two demonstrated difference between one attempt. When the mean scores were compared to determine the inter-examiner reliability, only one examiner's results were statistically different when compared with two others.

CONCLUSION

This study has demonstrated that the analysis stage of QLF is reliable between examiners and within multiple attempts by the same examiner, when analysing in vitro lesions. Novices at the technique should be trained before analysing experimental data.

Determination of the sensitivity and specificity of sibship calculations using AmpF lSTR Profiler Plus

In circumstances where a known DNA reference sample from the deceased's belongings or biological parents is not available, more complex kinship analyses are possible. The purpose of the work reported here is to determine the sensitivity and specificity of the sibship analysis utilising multiple STR loci. Using all nine Profiler Plus loci, likelihood ratios for biologically-related siblings ranged from slightly less than 1 to over 45,000. When allelic dropout was mimicked, likelihood ratios ranged from less than 1 to over 1,000. Thus, the results of this study have a direct application to forensic laboratories faced with identifications involving sibling comparisons.

Detection of in vitro demineralization of primary teeth using quantitative light-induced fluorescence (QLF)

INTRODUCTION

With the advent of remineralizing therapies and the new, conservative approach to restoration placement, interest in detecting and monitoring subclinical, precavitated lesions has increased. The increased understanding of clinicians about the processes of primary and secondary prevention and the detection of lesions to which these therapies may be applied, is one of the current goals in caries management. Quantitative light-induced fluorescence (QLF) is a new method for the detection of very early caries.

OBJECTIVES

To determine the ability of QLF to detect and longitudinally monitor in vitro enamel demineralization. To present the device to the paediatric community and present future in vivo uses of the device.

DESIGN

An in vitro study with combined in vivo pilot.

SAMPLE AND METHODS

Twelve previously extracted, caries free, primary molars were selected and prepared. Two teeth were randomly selected as controls. Teeth were prepared by gentle pumicing and coating in an acid-resistant nail-varnish, except for an exposed window on the buccal surface. QLF baseline images were taken and the teeth then exposed to a demineralizing solution. Teeth were removed at regular intervals (24, 48, 72, 96, 120, and 144 h), air-dried and QLF images taken. QLF images were analysed by a single, blinded examiner (to control, to length of exposure). Mineral loss, as measured by DeltaQ, was recorded.

RESULTS

Demineralization was noted in all experimental teeth by 48 h, and within 24 h in six teeth. The QLF successfully monitored the increase in mineral loss over time (P < 0.05). The detected lesions were not visible clinically until 144 h and then in only the most severe lesions. No demineralization was detected by QLF in control teeth. The device was user- and patient-friendly in vivo, detecting subclinical lesions.

CONCLUSION

Detection of very early mineral loss and subsequent monitoring of this loss is possible in primary teeth using QLF. The device is well suited to use in paediatric dentistry and offers applications for both clinicians and researchers. The determination of the status of carious lesions (active/inactive) will be possible with readings taken at recall appointments.

The effect of ambient light on QLF analyses

The use of optical methods in the diagnosis of early caries is developing rapidly. The introduction of the quantitative light-induced fluorescence (QLF) device has promised the use of a quantifiable technique in vivo. This study describes the effect that ambient light has upon the reliability of QLF analyses. Using human teeth and simulated lesions the study examined the effect of 15 different light levels on three severities of carious lesions. The study found that a light level of 88 lux could be employed in areas where QLF is to be used without significantly affecting the reported value, DeltaQ. This study impacts upon the health and safety issues surrounding QLF usage as well as ethical issues relating to working in dark environments.

Associated postmortem dental findings as an aid to personal identification

The use of the unique features of the human dentition to aid in personal identification is well accepted within the forensic field. Indeed, despite advances in DNA and other identification methodologies, comparative dental identifications still play a major role in identifying the victims of violence, disaster or other misfortune. The classic comparative dental identification employs the use of postmortem and antemortem dental records (principally written notes and radiographs) to determine similarities and exclude discrepancies. In many cases the tentative identification of the individual is unknown and therefore antemortem records cannot be located. In such a situation a dental profile of the individual is developed to aid the search for the individual's identity. With such a profile a forensic odontologist can identify and report indicators for age at time of death, race (within the four major ethnic groups) and sex. In addition to these parameters the forensic dentist may be able to give more insight into the individual. This paper outlines, for the non-expert, some of the additional personal information that can be derived from the teeth of the deceased, and which may assist in their ultimate identification.

Results of the 4th ABFO Bitemark Workshop--1999

Thirty-two certified diplomates of the American Board of Forensic odontology (ABFO) participated in a study of the accuracy of bitemark analysis. Examiner experience as board-certified odontologists ranged from 2 to 22 years. Examiners were given sets of photographs (a cast in 1 case) of 4 bitemark cases and asked to report their certainty that each case was truly a bitemark and the apparent value of the case as forensic evidence. Participants also received 7 occluding sets of dental casts, 1 correct dentition for each case and three unrelated to any of the cases, and asked to rate how certain they were that each set of teeth had made each bitemark. Receiver operating characteristic (ROC) analysis resulted in an accuracy score of 0.86 (95% CI=0.82-0.91). Youden's index was used to determine a cutoff point for determining an accuracy score for each case. Accuracy scores were significantly correlated with bitemark certainty and forensic value (P<0.001 in both cases) but not with examiner experience (P=0.958). The use of individual ROC analysis with weighted Youden's index to calibrate individual accuracy was also demonstrated.

The use of QLF to quantify in vitro whitening in a product testing model

BACKGROUND

Professional and consumer interest in whitening products continues to increase against a background of both increased oral health awareness and demand for cosmetic procedures. In the current legal climate, few dentists are providing 'in-office' whitening treatments, and thus many patients turn to home-use products. The most common of these are the whitening toothpastes. Researchers are keen to quantify the effectiveness of such products through clinically relevant trials.

AIM

Previous studies examining whitening products have employed a variety of stained substrates to monitor stain removal. This study aimed to quantify the removal of stain from human enamel using a new device, quantitative light-induced fluorescence (QLF). The experimental design follows that of a product-testing model.

MATERIALS AND METHODS

A total of 11 previously extracted molar teeth were coated with transparent nail varnish leaving an exposed window of enamel. The sound, exposed enamel was subject to a staining regime of human saliva, chlorhexidine and tea. Each of the eleven teeth was subjected to serial exposures of a positive control (Bocasan), a negative control (water) and a test product (Yotuel toothpaste). Following each two-minute exposure QLF images of the teeth were taken (a total of 5 applications). Following completion of one test solution, the teeth were cleaned, re-stained and the procedure repeated with the next solution. QLF images were stored on a PC and analysed by a blinded single examiner. The deltaQ value at 5% threshold was reported. ANOVA and paired t-tests were used to analyse the data.

RESULTS

The study confirmed the ability of QLF to longitudinally quantify stain reduction from human enamel. The reliability of the technique in relation to positive and negative test controls was proven. The positive control had a significantly (alpha = 0.05) higher stain removal efficacy than water (p = 0.023) and Yotuel (p = 0.046). Yotuel was more effective than water (p = 0.023).

CONCLUSION

The research community, the practicing clinician and the consumer all require sound product evaluation data. The use of human enamel specimens may offer more relevant clinical data. QLF has been designed as an in vivo device. Further development of the technique should permit in vivo clinical whitening trials.

Digital bite mark overlays--an analysis of effectiveness

U.S. courts have stated that witnesses must be able to identify published works that define operational parameters of any tests or procedures that form the basis of scientific conclusions. Such works do not exist within the field of bite mark analysis. As the most commonly employed analytical technique in bite injury assessment. this study defines quantifiable variables for transparent digital overlays. A series of ten simulated, postmortem bites were created on pigskin and, with accompanying overlays, assembled into cases. Using two separate studies with four examiner groups, the study defined values of intra- and inter-examiner reliability, accuracy. sensitivity, specificity, and error rates for transparent overlays. Methods and statistical treatments from medical decision-making and diagnostic test evaluation were employed. Forced decision models and receiver operating characteristic analyses were utilized. Sensitivity and specificity values are described. and the results are consistent with other dental diagnostic systems. It was concluded that the weak inter-examiner reliability values explain the divergence of odontologists' opinions regarding bite mark identifications often stated in court. The effect of training and experience of the examiners was found to have little effect on the effective use of overlays within this study. The authors conclude that further research is required so that the results of the current study can be placed into context, but this represents a significant first step in establishing the scientific basis for this aspect of forensic dentistry.

Lack of dental uniqueness between two bite mark suspects

The central dogma of bite mark analysis is based upon two assumptions. The first is that human teeth are unique, and the second is that sufficient detail of the uniqueness is rendered during the biting process to enable identification. Both of these assumptions have been challenged over recent years, and a healthy scientific skepticism surrounding bite mark analysis has developed. The case presented features two suspects whose dental arrangement was similar and, when compared to the bite mark, both demonstrated consistent features. Within a closed population of possible biters, one of the two suspects was responsible for the injury. The case is illustrated with photographic and overlay detail of the suspect's teeth and demonstrates the complexity of such cases. The authors call for greater caution when drawing conclusions from such cases and highlight the need for further research into the replication of dental features on human skin.

Adherence of forensic odontologists to the ABFO bite mark guidelines for suspect evidence collection

Boards and associations within forensic science have long been accepted as vehicles for the development and dissemination of protocols and recommendations for practice. Recent controversies surrounding bite mark analyses have brought the methods and practices of forensic dentists to the attention of both the courts and the media. In the mid-eighties the American Board of Forensic Odontology developed guidelines for bite mark analysis in response to unfavorable commentaries on the discipline by legal observers. The purpose of this study is to examine the adherence of board certified and noncertified forensic dentists to the guidelines for collection of evidence from bite mark suspects. A questionnaire was employed during an American Academy of Forensic Sciences meeting. Results showed that, in general, when the odontologists collected evidence they did adhere to the guidelines, although collection of salivary samples was not common. Of concern is the large number of odontologists who do not collect their own evidence from suspects. Police officers or other individuals often perform this task and therefore the guidelines must be disseminated to these groups to ensure that the maximum yield is obtained from bite mark evidence. A review of the materials used to collect evidence is also included with details of applications in forensic science.

A look at forensic dentistry--Part 2: teeth as weapons of violence--identification of bitemark perpetrators

Teeth are often used as weapons when one person attacks another or when a victim tries to ward off an assailant. It is relatively simple to record the evidence from the injury and the teeth for comparison of the shapes, sizes and pattern that are present. However, this comparative analysis is often very difficult, especially since human skin is curved, elastic, distortable and undergoing oedema. In many cases, though, conclusions can be reached about any role a suspect may have played in a crime. Additionally, traces of saliva deposited during biting can be recovered to acquire DNA evidence and this can be analyzed to determine who contributed this biological evidence. If dentists are aware of the various methods to collect and preserve bitemark evidence from victims and suspects it may be possible for them to assist the justice system to identify and prosecute violent offenders. This paper reviews the recognition and recovery of this evidence and provides insight into modern methods used to investigate bitemark evidence from heinous crimes.