Emissivity evaluation of human enamel and dentin.

Background: Human enamel and dentin temperatures have been assessed with non-contact infrared imaging devices for safety and diagnostic capacity and require an emissivity parameter to enable absolute temperature measurements. Emissivity is a ratio of thermal energy emitted from an object of interest, compared to a perfect emitter at a given temperature and wavelength, being dependent on tissue composition, structure, and surface texture. Evaluating the emissivity of human enamel and dentin is varied in the literature and warrants review. The primary aim of this study was to evaluate the emissivity of the external and internal surface of human enamel and dentin, free from acquired or developmental defects, against a known reference point. The secondary aim was to assess the emissivity value of natural caries in enamel and dentin. Method: Fourteen whole human molar teeth were paired within a thermally stable chamber at 30°C. Two additional teeth (one sound and one with natural occlusal caries-ICDAS caries score 4 and radiographic score RB4) were sliced and prepared as 1-mm-thick slices and placed on a hot plate at 30°C within the chamber. A 3M Scotch Super 33 + Black Vinyl Electrical Tape was used for the known emissivity reference-point of 0.96. All samples were allowed to reach thermal equilibrium, and a FLIR SC305 infrared camera recorded the warming sequence. Emissivity values were calculated using the Tape reference point and thermal camera software. Results: The external enamel surface mean emissivity value was 0.96 (SD 0.01, 95% CI 0.96-0.97), whereas the internal enamel surface value was 0.97 (SD 0.01, 95% CI 0.96-0.98). The internal crown-dentin mean emissivity value was 0.94 (SD 0.02, 95% CI 0.92-0.95), whereas the internal root-dentin value was 0.93 (SD 0.02, 95% CI 0.91-0.94) and the surface root-dentin had a value of 0.84 (SD 0.04, 95% CI 0.77-0.91). The mean emissivity value of the internal enamel surface with caries was 0.82 (SD 0.05, 95% CI 0.38-1.25), and the value of the internal crown-dentin with caries was 0.73 (SD 0.08, 95% CI 0.54-0.92). Conclusion: The emissivity values of sound enamel, both internal and external, were similar and higher than those of all sound dentin types in this study. Sound dentin emissivity values diminished from the crown to the root and root surface. The lowest emissivity values were recorded in caries lesions of both tissues. This methodology can improve emissivity acquisition for comparison of absolute temperatures between studies which evaluate thermal safety concerns during dental procedures and may offer a caries diagnostic aid.

Paediatric periodontal screening methods in undergraduate dental schools.

Introduction: Many forms of periodontal diseases affect children and adolescents. The simplified basic periodontal examination (BPE) is a screening tool for children aged seven to 17, which enables early recognition of such diseases. This study aims to investigate and compare methods of periodontal health assessments in the 'under-18s' across dental schools in the UK. Materials and method: A web-based questionnaire was issued via email to teaching members of staff in each of the 16 undergraduate dental universities across the UK. Results: Out of the 16 correspondents, ten universities completed the questionnaire, giving a response rate of 63%. All respondents were aware of methods of periodontal screening for children and adolescents such as the simplified BPE. All universities taught and used the 'simplified BPE'. The majority of universities started paediatric clinics in year three and carried out practical periodontal assessments in children aged seven and above, at first visit and at recall. Discussion and conclusion: All UK dental schools were aware of, taught and used the simplified BPE as a method of periodontal assessment. Most universities seemed to comply with the guidelines being implemented.

Surfing the spectrum - what is on the horizon?

Diagnostic imaging techniques have evolved with technological advancements - but how far? The objective of this article was to explore the electromagnetic spectrum to find imaging techniques which may deliver diagnostic information of equal, or improved, standing to conventional radiographs and to explore any developments within radiography which may yield improved diagnostic data. A comprehensive literature search was performed using Medline, Web of Knowledge, Science Direct and PubMed Databases. Boolean Operators were used and key-terms included (not exclusively): terahertz, X-ray, ultraviolet, visible, infra-red, magnetic resonance, dental, diagnostic, caries and periodontal. Radiographic techniques are primarily used for diagnostic imaging in dentistry, and continued developments in X-ray imaging include: phase contrast, darkfield and spectral imaging. Other modalities have potential application, for example, terahertz, laser doppler and optical techniques, but require further development. In particular, infra-red imaging has regenerated interest with caries detection in vitro, due to improved quality and accessibility of cameras. Non-ionising imaging techniques, for example, infra-red, are becoming more commensurate with traditional radiographic techniques for caries detection. Nevertheless, X-rays continue to be the leading diagnostic image for dentists, with improved diagnostic potential for lower radiation dose becoming a reality.

Direct and indirect effects of interdental hygiene in a clinical trial.

Many randomized controlled trials (RCTs) in dental research test the efficacy of interventions on more than one outcome variable. Univariate methods, such as the t test or analysis of covariance, cannot evaluate the efficacy of interventions on multiple outcomes simultaneously. The aim of this study was to use structural equation modeling (SEM) to re-analyze a RCT, comparing the effects of pre-curved interdental brushes and flossing on probing pocket depth (PPD), plaque indices, and bleeding on probing (BOP) measured at baseline, intermediate, and final examinations. Results of SEM showed that the observed greater reduction in PPD and BOP in persons using interdental brushing than in those flossing is due mainly to the greater efficiency in plaque removal with the interdental brushes (indirect effect) rather than to the compression of the interdental papillae (direct effect). In contrast, smokers showed less BOP at baseline but also less improvement in BOP through direct effects.

Periodontal diseases in children and adolescents.

Unlike in adults, currently there are no nationally agreed guidelines for the assessment of periodontal diseases in children and adolescents. This paper considers the range of periodontal diseases that can affect youngsters and documents a simple periodontal screening system for the younger age groups. It includes principles of periodontal diagnosis and management for the practitioner to apply to the young patient and considers when to treat in practice and when to refer to a specialist.

Attitudes, awareness and oral health-related quality of life in patients with diabetes.

The purpose of this study was to assess the knowledge diabetic patients have of their risk for periodontal disease, their attitude towards oral health and their oral health-related quality of life (OHRQL). One hundred and one consecutive patients (age range 31-79 years) recruited from a diabetic outpatient clinic participated in the study. Twenty-seven per cent of participants had type 1 diabetes, 66% type 2 and 7% did not know what type of diabetes they had. The length of time since participants were diagnosed as diabetic ranged from 1 to 48 years. Metabolic control of diabetes as determined by HbA1c levels ranged from 6.2% to 12.0% compared with the normal range of 4.5-6.0%. Thirty-three per cent of participants were aware of their increased risk for periodontal disease, 84% of their increased risk for heart disease, 98% for eye disease, 99% for circulatory problems and 94% for kidney disease. Half of the participants who were aware of their increased risk for periodontal disease had received this information from a dentist. Dental attendance was sporadic, with 43% reporting attendance within the last year. OHRQL was not significantly affected by the presence of diabetes in the group surveyed, in comparison with a previous survey of non-diabetic patients. A significant association was found between metabolic control and dentate status. Awareness of the potential associations between diabetes, oral health and general health needs to be increased in diabetic patients.

Validation of a model to evaluate the role of radiographs in the diagnosis and treatment planning of periodontal diseases.

OBJECTIVES: The purposes of this study were (i) to see if an indirect method of design (paper patients) could be developed for study of change affected by radiographs on diagnostic outcome and planned treatment of periodontal patients and (ii) to investigate the effect of the nature of clinical examination on the value of radiographs in reaching a periodontal diagnosis. Paper cases could allow the design of examiner blind studies where repeatability could be assessed. METHODS: 201 patients were assigned to one of four groups and clinically assessed according to group specifications. Radiographs were taken. Periodontal diagnoses and treatment plans were drawn up for each patient with and without radiographic information (real patient). Simulated paper transcriptions were made for each subject and diagnoses and treatment plans were again drawn up (paper patient). RESULTS: For many diagnoses and treatment options assessments were similar for real and paper patients. There was substantial agreement between periodontal diagnoses reached from real and paper assessments (kappa=0.68). Greater differences were seen for extractions and periodontal surgery. Paper assessments better replicated real assessments when more thorough clinical examinations were undertaken. The relatively time efficient Group 2 clinical assessment appeared to perform similarly to the extensive Group 4 clinical assessment. CONCLUSIONS: The model described may be useful for simulating real patients for studies of this nature. The Group 2 assessment appeared to give sufficient clinical information for patient management and may be an appropriate choice for initial diagnosis and treatment planning of periodontal patients.

Problems of correlations between explanatory variables in multiple regression analyses in the dental literature.

Multivariable analysis is a widely used statistical methodology for investigating associations amongst clinical variables. However, the problems of collinearity and multicollinearity, which can give rise to spurious results, have in the past frequently been disregarded in dental research. This article illustrates and explains the problems which may be encountered, in the hope of increasing awareness and understanding of these issues, thereby improving the quality of the statistical analyses undertaken in dental research. Three examples from different clinical dental specialties are used to demonstrate how to diagnose the problem of collinearity/multicollinearity in multiple regression analyses and to illustrate how collinearity/multicollinearity can seriously distort the model development process. Lack of awareness of these problems can give rise to misleading results and erroneous interpretations. Multivariable analysis is a useful tool for dental research, though only if its users thoroughly understand the assumptions and limitations of these methods. It would benefit evidence-based dentistry enormously if researchers were more aware of both the complexities involved in multiple regression when using these methods and of the need for expert statistical consultation in developing study design and selecting appropriate statistical methodologies.

Statistical power for analyses of changes in randomized controlled trials.

Randomized controlled trials (RCTs) are widely recommended as the most useful study design to generate reliable evidence and guidance to daily practices in medicine and dentistry. However, it is not well-known in dental research that different statistical methods of data analysis can yield substantial differences in study power. In this study, computer simulations are used to explore how using different univariate and multivariate statistical methods of analyzing change in continuous outcome variables affects study power, and the sample size required for RCTs. Results show that, in general, analysis of covariance (ANCOVA) yields greater power than other statistical methods in testing the superiority of one treatment over another, or in testing the equivalence between two treatments. Therefore, ANCOVA should be used in preference to change score or percentage change score to reduce type II error rates.

Use of the basic periodontal examination and radiographs in the assessment of periodontal diseases in general dental practice.

OBJECTIVES: The aims of this study were to investigate (1) the use of the basic periodontal examination (BPE) by general dental practitioners (GDPs) and their selection of radiographs for the assessment of periodontal disease and (2) whether this selection concurred with existing selection (referral) criteria. METHODS: Three mailings of a self-completion questionnaire were sent to 800 GDPs working in the National Health General Dental Service in England and Wales. Dentists were presented with six clinical scenarios for which they were asked to describe their use of radiographs. RESULTS: Ninety-one percent of dentists reported that they used the BPE in new patients, with 56% using it for all patients; 84% of dentists used BPE in recall patients. BPE use was related to the dentists' age and postgraduate qualifications. There was a wide variation in the radiographic views used for periodontal disease assessment. The choice of radiographs was not generally in line with the Faculty of General Dental Practitioners (UK) 1998 selection criteria, particularly for the clinical scenarios of pocketing >5 mm, irregular pocketing or pockets associated with teeth with heavy restorations. Sixty seven percent of dentists concurred with recommendations for radiographs for a suspected periodontal-endodontic lesion. CONCLUSIONS: A majority of dentists reported clinical screening for periodontal diseases using the BPE. There was considerable variation in the selection and use of radiographs and practice was not in line with existing guidelines for many clinical situations. Evidence-based referral criteria should be actively promoted to ensure high standards of radiographic practice in general dental practice.

Radiographic equipment and techniques used in general dental practice: a survey of general dental practitioners in England and Wales.

OBJECTIVES: The aims of this study were to determine the self-reported use of panoramic radiography, D- and E-speed film, rectangular collimation, film holders, equipment fitted with a long spacer cone (>200 mm) and the bisecting angle and paralleling techniques by general dental practitioners and to see if use was related to the dentists' age and postgraduate qualifications. METHODS: Three mailings of a self-completion questionnaire were circulated to 800 general dental practitioners working in the National Health General Dental Service in England and Wales. RESULTS: A response rate of 74% was achieved. Sixty-one percent of general dental practitioners reported use of panoramic equipment. Fifty percent of dentists always used E-speed film and 18% always used rectangular collimation. Sixty-eight percent of dentists always used bitewing film holders though fewer (37%) used periapical film holders. Sixty-three percent of dentists always used a long cone. The bisecting angle technique was used by 70% of dentists with 22% always using this technique for periapical radiographs. Thirty-one percent always used the paralleling technique. Use of panoramic equipment, periapical film holders, bisecting angle and paralleling techniques were associated with the dentists' age. Use of periapical film holders, bisecting angle and paralleling techniques and rectangular collimation were associated with dentists' postgraduate qualifications. CONCLUSIONS: There are several features of radiographic equipment and techniques that can aid high quality imaging and reduce patient dose. Although a number of these are being used in general dental practice in England and Wales they have yet to achieve universal adoption.

Periodontal diseases in children and adolescents: 2. Management.

Many of the periodontal diseases affecting children and adolescents can be successfully managed in general dental practice. The decision to treat the young patient in the practice setting or to refer to a periodontal specialist will depend on the complexity of treatment, patient factors and the expertise of the practitioner. Treatment should be provided in three phases: the initial cause-related phase is aimed at controlling microbial plaque; the corrective phase is intended to restore function and aesthetics; supportive periodontal therapy is aimed at preventing recurrence and progression of periodontal disease. Even in cases requiring specialist referral, the dental team in general practice has a key role in the initial and supportive phases of therapy.

Periodontal diseases in children and adolescents: I. Aetiology and diagnosis.

A number of periodontal diseases, some forms of which can be aggressive, can affect children and adolescents. Plaque is the key aetiological agent but local and systemic factors that can modify the response of the periodontal tissues to plaque may be identified from the history and during examination of the child or adolescent. Periodontal screening should be an integral part of the dental examination of younger individuals. It can be used in conjunction with the history and examination to reach a diagnosis, which then forms the basis for future management.

Gingival recession-its significance and management.

OBJECTIVES: To review the prevalence and current concepts of the mechanisms and aetiology of gingival recession and present the principles of assessment and management of the patient with gingival recession. DATA AND SOURCES: The literature was searched for review and original research papers relating prevalence, mechanisms, aetiology, assessment, and treatment of gingival recession using Medline and manual tracing of references cited in key papers otherwise not elicited. STUDY SELECTION: Studies with gingival recession as focus and pertinent to key aspects of review. RESULTS: Gingival recession is a common condition and its extent and prevalence increase with age. Many factors including trauma and periodontal disease have a role in its aetiology. The patient may develop signs and symptoms including pain from exposed dentine, root caries and aesthetic concerns. Management of gingival recession requires thorough patient assessment, identification of aetiological factors, and recording and monitoring of the extent and severity of the condition. Treatment should be directed at prevention of further progression and the control of symptoms and disease. The patient's aesthetic concerns should be appreciated. Surgical treatment of recession may be indicated to cover exposed root surfaces. Many surgical techniques have been described with varied reported clinical effectiveness. CONCLUSIONS: Gingival recession should be thoroughly assessed and evaluated in order to offer the most suitable management.

Morphology and elemental composition of subgingival calculus in two ethnic groups.

BACKGROUND: The aim of the present study was to compare the morphology and elemental composition of subgingival calculus between Indo-Pakistani and Caucasian patient groups. METHODS: Extracted teeth from 14 Indo-Pakistani and 19 Caucasian subjects were collected. Of these, 12 Indo-Pakistani and 10 Caucasian teeth had sufficient subgingival calculus for analysis. Subgingival calculus present on the 22 teeth was classified into six morphological types: 1) crusty/spiny/nodular; 2) ledge/ ring; 3) thin, smooth veneers; 4) finger/fern-like; 5) individual islands/spots; or 6) supramarginal on submarginal. Subgingival calculus was zoned: coronal, mid, and apical. A sample obtained from each zone was subdivided to allow 3 separate analyses: transmission electron microscopic (TEM) x-ray microanalysis for elemental composition, fluoride analysis, and carbonate analysis. RESULTS: Crusty/spiny/nodular, ledge/ring, and thin, smooth veneers were more commonly found in the Indo-Pakistani group; individual islands were more prevalent in the Caucasian subjects. Supramarginal on submarginal calculus was found only in the Indo-Pakistani group. No finger/fern-like deposits were found. No differences within or between the two ethnic groups were found with regard to calcium:phosphate ratios, fluoride, or carbonate content. However, the Indo-Pakistani group showed significantly lower levels of sodium in apical samples than in coronal samples (ANOVA, F1,16 = 5.98, P= 0.03), and significantly lower levels of sodium (ANOVA, F1,12 = 4.75, P= 0.05) and magnesium (ANOVA, F1,12 = 5.16, P= 0.04) in apical samples than in those from Caucasians. After adjusting for smoking, the magnesium results remained significant (ANOVA, F2,11 = 4.64, P= 0.05). CONCLUSIONS: Subgingival calculus demonstrated differences in morphology between these two ethnic groups and differences in elemental composition, which may influence its overall solubility and contribute to its greater accretion in the Indo-Pakistani subjects.

The usefulness of radiographs in diagnosis and management of periodontal diseases: a review.

OBJECTIVES: To review the periodontally significant diagnostic information obtainable from radiographs and the stages during periodontal therapy when the information may influence patient management and treatment outcomes. DATA: Confined to studies involving conventional radiography, as this remains the commonest imaging method in clinical dental practice and primary dental care setting. SOURCES: Literature was reviewed using Medline and manual tracing of references cited in key papers not otherwise elicited. STUDY SELECTION: Studies were selected in order to (i) define the role of radiographs in periodontal diagnosis and management at the initial, corrective and supportive (maintenance) phases of periodontal therapy and (ii) critically review the evidence for the value added by radiographs. CONCLUSIONS: Radiographs provide diagnostic information on alveolar bone levels, plaque retention factors, caries, furcation defects, subgingival calculus and additional pathology. Features visualised are dependent on the radiographic view. A relationship exists between probing attachment loss and radiographic bone height, with a range in level of correlation; clinical attachment may correspond more closely to surgical measurements of bone height. Radiographs can be used in planning initial, corrective and supportive phases of therapy, though some decisions may be made on clinical assessments alone. Evidence in the literature on benefit gained from radiographs taken for periodontal patients is sparse; the extent to which they influence the treatment provided and treatment outcomes is poorly addressed. Further research is indicated to define the role of radiographs when managing the periodontal patient to maximise the potential gain for the patient.

Subgingival calculus: where are we now? A comparative review.

OBJECTIVE: To critically analyse the formation, composition, ethnic variations and pathogenic potential of subgingival calculus in comparison with supragingival calculus. DATA SOURCES: Using CD-ROM and index medicus, scientific papers relating to subgingival calculus or subgingival and supragingival calculus written in the English language since 1960 were considered, with the emphasis on more recent articles. STUDY SELECTION: Studies were selected for their relevance and contemporary nature re:composition and formation of dental calculus and comparisons of ethnic groups with regard to dental calculus, especially subgingival calculus. Some similar studies were not included. DATA EXTRACTION: Abstracts of studies were kept brief unless particularly important to the review. Population, methodology, statistics and accurate conclusions were used as important guides to the quality and validity of studies. DATA SYNTHESIS: Similarities and differences between supragingival and subgingival calculus in composition and formation were shown. Different morphological types of subgingival calculus were demonstrated. There was evidence for an association between calculus formation and ethnicity with regard to supragingival and subgingival calculus, and an association between subgingival calculus composition and ethnicity was indicated. CONCLUSIONS: An association between ethnicity and subgingival calculus formation and composition was found. Further research into the reasons for these ethnic differences in dental calculus and the role of the mineral constituents especially of subgingival calculus would be valuable.

A practice-based randomised controlled trial of the efficacy of an electric and a manual toothbrush on gingival health in patients with fixed orthodontic appliances.

OBJECTIVES: The aim of the present study was to evaluate the efficacy of an electric toothbrush with a specially designed orthodontic brush head compared with a manual toothbrush in controlling plaque and gingivitis in patients with fixed orthodontic appliances over an 8-week period in a dental practice setting. METHODS: This was a randomised controlled, single blind, stratified, parallel group trial conducted in two specialist orthodontic dental practices by a specialist orthodontist. Group 1 comprised 41 subjects who used the electric toothbrush and Group 2 consisted of 43 subjects who brushed with a manual toothbrush around the orthodontic appliance for a timed 2 minutes twice daily for 8 weeks. Plaque around the fixed appliance attachments was measured using an orthodontic modification to the Silness and Loe plaque index, while gingival condition was scored using the gingival index and Eastman interdental bleeding index. RESULTS: There was baseline balance for all clinical variables (p > 0.05). Both groups had significantly less plaque after 8 weeks than at baseline (p < 0.001) but the group using the electric brush also had significantly less interdental gingival bleeding, as determined by the Eastman interdental bleeding index both at week 4 (p < 0.001) and week 8 (p = 0.004). The majority of subjects (n = 54, 64.3%) preferred the electric toothbrush. CONCLUSIONS: In conclusion, the results from this study would suggest that use of an electric toothbrush with an orthodontic brush head may be of benefit in promoting gingival health in fixed orthodontic appliance patients; however, the long-term effects (over at least 6 months) need to be evaluated.

The reasons for tooth extractions in adults and their validation.

OBJECTIVES: To investigate the primary reasons for the extraction of permanent teeth in adults and to validate the dentists' reasons for extraction. METHODS: Twenty-one dentists in the Greater Manchester area took part in the study. These dentists provided extracted teeth stored in 10% buffered formal saline together with details of the patient's age, sex, dental attendance pattern and the reason for extraction. In order to validate the reasons for extraction, teeth were examined for the presence or absence of coronal and root caries. A subgroup of 80 teeth, half of which were extracted primarily for caries and half for periodontal reasons were selected, stained and attachment loss measured at six sites per tooth to validate periodontal reasons for extraction. RESULTS: Three hundred and eighty-nine teeth were collected of which 37% were extracted primarily due to caries and 29% due to periodontal disease. Caries was the main reason for extraction in patients under 50 years, whereas periodontal disease was the commonest reason in the over-50 age group. Irregular attenders had more extractions for caries than regular attenders but attendance pattern did not affect the proportion of teeth extracted for periodontal reasons. The mean greatest loss of attachment on teeth extracted for periodontal reasons was 12 mm compared with 6.5 mm for caries. CONCLUSION: In this group of patients caries was the most common reason for extraction of teeth but periodontal disease became a more important reason for extraction after 50 years of age. The study validated the dentists' given reason for extraction.