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Biomedical subjects

Iain A Pretty

Publications and source records attributed to Iain A Pretty.

At least 19 recordsLinked to original sources
PubMed2006

Comparison of the ability of different colour indices to assess changes in tooth whiteness.

OBJECTIVES: The study investigates the suitability of different whiteness indices and colour parameters in assessing changes in tooth whiteness using a digital-colour imaging system. METHODS: Forty-six male and female subjects aged 18-70 years participated in the study and were divided into two groups. The control group was given a standard "non-whitening" dentifrice (Colgate Great Regular Flavour) and the test group received whitening strips (crest white strips). The latter contained 6% hydrogen peroxide and were worn for 30 min twice daily on the six maxillary anterior teeth. Digital images of teeth were captured using a Jai 3CCD digital camera with annular LED illumination array and the data obtained was used to calculate colour parameters (L*, a* and b*) and whiteness indices (WIC, WIO, W). Colour differences (delta L, delta a, delta b and delta E) and differences in whiteness indices were obtained and were compared between the test and control groups. Reliability and repeatability of the instrument were checked by comparing the digital data to the clinical data and also by comparing data obtained from different camera views for the same tooth. RESULTS: The test group showed significant changes in the colour parameters and whiteness indices over the 2-week period. It also showed significant correlation between the digital data obtained from lateral and central camera views for the same teeth. Digital data showed a similar trend to that of clinical data. The WIO index demonstrated the strongest discrimination between the test and control groups. CONCLUSION: The WIO index is appropriate for assessing changes in tooth whiteness. The digital imaging system is reproducible and reliable in evaluating changes in whiteness of teeth.

Adolescent↗
PubMed2006

Caries detection and diagnosis: novel technologies.

Recent years have seen an increase in research activity surrounding diagnostic methods, particularly in the assessment of early caries lesions. The drive for this has come from two disparate directions. The first is from the dentifrice industry who are keen to develop techniques that would permit caries clinical trials (CCTs) to be reduced in duration and subject numbers to permit the investigation of novel new anti-caries actives. The second is from clinicians who, armed with the therapies to remineralise early lesions are now seeking methods to reliably detect such demineralised areas and implement true preventative dentistry. This review examines novel technologies and the research supporting their use. Techniques based on visual, optical, radiographic and some emerging technologies are discussed. Each have their benefits although systems based on the auto-fluorescence (such as QLF) of teeth and electrical resistance (such as ECM) seem to offer the most hope for achieving reliable, accurate detection of the earliest stages of enamel demineralisation.

Dental Caries↗
PubMed2006

The barriers to achieving an evidence base for bitemark analysis.

Forensic dentistry is the union of two scientific disciplines, both of which are undergoing a renewed scientific rigor. In forensic science the advent of the Daubert ruling has required that judges assess the forensic value of 'expert testimony' ensuring that techniques, methodologies and practices are not only commonly accepted (as was the previous hurdle during the Frye era) but that error rates, assessment of reliability and validation studies are published to support their use. This new degree of judicial scrutiny has been mirrored in the field of dentistry itself, where organisations search and summarise randomised controlled trials in order to recommend best practice and devise clinical care pathways that are firmly grounded in proven scientific research. Despite the obvious drive from both of these professions, forensic dentistry, and in particular the sub-discipline of bitemark analysis, has been remarkably slow to address the obvious deficiencies in the evidence base that underpins this element of forensic science. Reviews of the literature reveal that the vast majority of published works are case reports, and very little primary literature exists. This paper reviews those studies that have assessed aspects of bitemark analysis including the crucial issue of the uniqueness of the human dentition; the application of transparent overlays and the application of statistical probabilities in bitemark conclusions. There are numerous barriers to undertaking high quality research in the field of bitemark analysis, the most important of which is the use of a gold-standard that is acceptable both in terms of diagnostic research but is also forensically relevant. If bitemark analysis is to continue to play a role in the judicial process then there is an urgent need for high quality studies that meet the levels of forensic and scientific scrutiny applied to other disciplines within the criminal justice system. Studies are required to determine not that the human dentition is unique, but how this asserted uniqueness is represented on human skin and other substrates. The error rates associated with the analysis of bitemarks are required on a procedural level as well as an individual practitioner basis and scales and interpretative indices of bitemark severity and forensic significance should be validated and introduced into common use.

Bites, Human↗
PubMed2006

Contemporary methods of labeling dental prostheses--a review of the literature.

Forensic identification (ID) based on an assessment of the dentition is commonplace. However, despite an increase in the oral health of Western populations, there are still many millions of individuals who are edentulous and whom have been treated with completed dentures. In the United Kingdom alone over 300,000 patients are rendered edentulous each year. In order to facilitate the ID of such individuals a number of forensic and governmental organizations have recommended that dentures be labeled. A number of labeling systems exist which can be broadly separated into inclusion systems, marking systems, and novel methods. Each of the commonly described systems are demonstrated with an assessment of their strengths and weaknesses. It is recommended that an inclusion denture marker, preferably metallic, should be used in order to withstand the most common postmortem assaults.

Denture Identification Marking↗
PubMed2006

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

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

Dental Devices, Home Care↗
PubMed2006

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

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

Consumer Product Safety↗
PubMed2005

The forensic and investigative significance of reverse paternity testing with absent maternal sample.

The authors are involved in the extraction of DNA material from calcified tissues, oftentimes teeth, and analysis of such material to assist the investigative process, frequently by confirming the identity of the victim. Biologic or molecular techniques for the purposes of human identification have evolved to allow increasingly discriminating tests for use in criminal and noncriminal death investigations, as well as paternity disputes. The goal of such tests is to either include 2 samples (ie, they are from the same person, or in the case of paternity, they are from related individuals) or exclude 2 samples (ie, they are from different people or from unrelated individuals). Regardless of the system used and when data error has been eliminated, an exclusionary conclusion is irrefutable. The probability of excluding the falsely accused has steadily increased over the years as new methods are developed. Conventional ABO blood typing, for example, has a probability of exclusion (PE) of only 17%. This value increases to 53% with the inclusion of the Rh and MN systems. Additional serological markers can provide a probability of exclusion of greater than 99%. Today, the current method of choice for human identification is the polymerase chain reaction for the amplification of short tandem repeat (STR) multiplexes. This paper discusses the implications of nonpaternity in reverse paternity testing when only paternal DNA is available.

ABO Blood-Group System↗
PubMed2004

A closer look at diagnosis in clinical dental practice: part 1. Reliability, validity, specificity and sensitivity of diagnostic procedures.

Dentists are involved in diagnosing disease in every aspect of their clinical practice. A range of tests, systems, guides and equipment--which can be generally referred to as diagnostic procedures--are available to aid in diagnostic decision making. In this era of evidence-based dentistry, and given the increasing demand for diagnostic accuracy and properly targeted health care, it is important to assess the value of such diagnostic procedures. Doing so allows dentists to weight appropriately the information these procedures supply, to purchase new equipment if it proves more reliable than existing equipment or even to discard a commonly used procedure if it is shown to be unreliable. This article, the first in a 6-part series, defines several concepts used to express the usefulness of diagnostic procedures, including reliability and validity, and describes some of their operating characteristics (statistical measures of performance), in particular, specificity and sensitivity. Subsequent articles in the series will discuss the value of diagnostic procedures used in daily dental practice and will compare today's most innovative procedures with established methods.

Decision Support Techniques↗
PubMed2004

A closer look at diagnosis in clinical dental practice: part 2. Using predictive values and receiver operating characteristics in assessing diagnostic accuracy.

When a clinician is planning to use a diagnostic test or procedure, it is important to establish the likelihood that an individual patient is affected by the condition or disease; this determination depends on predictions that are affected by various features of the diagnostic procedure. In this regard, sensitivity and specificity are limited because they describe the results of a procedure in a dichotomous way: the result is either positive or negative. However, many clinical procedures are not dichotomous, such as probing of periodontal pockets or assessment of radiographs for caries, and in these situations, a range of features is examined to produce a degree of certainty regarding the presence or absence of disease. This article examines predictive values and receiver operating characteristic (ROC) analysis, an algorithm that combines various statistical features of diagnostic procedures to assess the effectiveness of nondichotomous procedures without imposing an arbitrary threshold.

Area Under Curve↗
PubMed2004

A closer look at diagnosis in clinical dental practice: part 3. Effectiveness of radiographic diagnostic procedures.

This article, the third in a series, uses the tools described in the first 2 articles to examine some of the radiographic diagnostic procedures that are employed regularly in dental practice. With a general grounding in the meaning of terms such as sensitivity, specificity, thresholds, kappa coefficients, and predictive values, the reader should now be a more discerning user of the operating characteristic data for dental diagnostic procedures. By re-examining some of these procedures in terms of their effectiveness, accuracy and validity, dental practitioners should be able to use the procedures in a more targeted manner and gain the maximum benefit from their results. With a better understanding of the value of a diagnostic test, the clinician's decision-making process will be far better informed. For example, knowing that a certain radiographic view is associated with a 60% false-positive rate for identifying occlusal caries will preclude blind trust in the results and will help the informed clinician attribute a realistic weight to the radiographic findings. This article considers diagnostic procedures in common use in North American practice, with special emphasis on radiography.

Alveolar Bone Loss↗
PubMed2004

A closer look at diagnosis in clinical dental practice: part 5. Emerging technologies for caries detection and diagnosis.

Parts 5 and 6 of this series examine innovations in diagnostic and management procedures and assess their potential to become everyday tools of the dental clinician. This paper examines some of the diagnostic tools supporting a philosophical shift in mainstream dental practice from concern with extensively decayed teeth to a focus on detecting incipient demineralized tissues. With the latter approach, the incipient carious process can be reversed by promoting enamel remineralization and thus eliminating the need for restorative intervention. Numerous methods and devices have been developed to detect, diagnose and monitor such lesions, and several have been produced in versions that may appeal to dental practitioners. This paper considers 3 of these methods and devices: the DIAGNODent laser device, quantitative light-induced fluorescence and the Digital Imaging Fiber-Optic Transillumination device. Each technique is illustrated, the research on its effectiveness is assessed to determine usefulness to the practitioner, and the comparative advantages of the 3 adjunct tools are discussed.

Dental Caries↗
PubMed2004

Self-extraction of teeth involving gamma-hydroxybutyric acid.

A case involving self-extraction of teeth linked to the abuse of gamma-hydroxybutyric acid (GHB) is reported. A 28-year-old woman and her 29-year-old boyfriend were discovered by paramedics following an extensive period of GHB use. The paramedics were alerted by a neighbor who had heard screaming from the house. On presentation to the accident and emergency department, it was noted that the female had 18 fresh extraction sockets visible intra-orally. At the scene, a mirror, a pair of pliers, and a bowl containing human teeth were found. Charges of assault were taken to the courts against the boyfriend who was subsequently acquitted. Odontological evidence centered on whether or not it was possible to self-extract the teeth using the pliers found. This case is the first to describe possible oral self-mutilation under the influence of GHB and odontologists should always consider self-injury as an explanation for intra- and perio-oral injuries of unknown origin.

Adjuvants, Anesthesia↗
PubMed2003

The reliability of digitized radiographs for dental identification: a Web-based study.

In the era of Daubert and other judicial rulings pertaining to the acceptability of forensic evidence, it is increasingly important that experts are able to testify that their methods have been scientifically tested and that error rates and other factors relating to reliability have been published. The purpose of this study was to determine the reliability of digitized radiographic comparisons for the purposes of dental identification. Participants with various forensic backgrounds and experience levels were passively recruited to the website. Ten forensic identification cases composed of antemortem and postmortem dental radiographs were supplied to examiners using a bespoke website. Participants responded to the cases on two occasions after a one-month washout interval using the ABFO conclusion levels for forensic identifications. A total of 115 first attempts and 87 matched second attempts were received. Of the total responses, 72% were dentally trained respondents who had completed at least one forensic identification case; of these, 38% were experienced forensic dentists who had completed more than 25 identifications. Data relating to accuracy, intra- and inter-examiner agreement, and the effect of case difficulty are presented. Mean accuracy was 85.5% for all cases, with the experienced forensic dentists obtaining a 91% success rate. The inter-examiner agreement on the negative identification cases was classified as poor. The data suggest that dental identifications resulting from the comparison of postmortem and antemortem radiographs are valid, accurate, and reliable when undertaken by experienced odontologists.

Analysis of Variance↗
PubMed2002

Forensic dentistry and human bite marks: issues for doctors.

The human dentition can be used as a weapon of attack or defence. Bite mark injuries are common in cases of sexual assault, child abuse and homicide. Many bite injuries are first seen in casualty departments where quick and proper recovery of evidence can assist in analysing these injuries. This article describes different bite injuries, collection of evidence and comparative analysis methods.

Bites, Human↗
PubMed2002

Forensic implications of biting behavior: a conceptually underdeveloped area of investigation.

Within the context of a criminal investigation the human bitemark traditionally provides the forensic dentist with both physical and biological evidence. In recent years, however, examples exist where in addition to discussing physical and biological evidence, expert witnesses have also testified in court regarding the behavioral aspects of biting behavior. Interested in this additional source of evidence, the authors reviewed the research literature from which biting behavior could be explained. The review found a hiatus of empirical knowledge in this respect, with only two papers seemingly related to the topic. With this dearth of knowledge in mind, the authors present a framework for further analysis and tentatively suggest reasons for biting behaviors, using a range of psychological models. The article ends with a cautionary note that vague and often misleading behavioral assumptions must not be applied to bitemark testimony until further data are available.

Aggression↗
PubMed2002

Dental participants in mass disasters--a retrospective study with future implications.

Mass casualty incidents continue to require the services of forensic dentists to determine the identity of victims. Across North America and Europe. teams of forensic dentists train, using mock disaster exercises, to prepare for such duties. It is vital that these mock exercises simulate the features of real disaster situations as far as possible. In order to inform those responsible for the design and implementation of mock exercises, a study was undertaken to determine the features of actual disasters that dental personnel had attended. Using a questionnaire, data were solicited from 38 odontologists. The average number of disasters attended by the respondents was eight, with an average casualty number of 94. Aircraft crashes were the most frequent cause of disasters that were attended by the odontologists. The authors conclude that future mock disaster exercises should replicate features of aircraft crashes as closely as possible by using commingled, fragmented, and burned remains. In addition, mock disasters should require the identification of a realistic number of individuals to ensure authenticity and the maximum logistical preparedness of participants.

Accidents, Aviation↗
PubMed2002

The use of quantitative light-induced fluorescence (QLF) to identify composite restorations in forensic examinations.

There has been a large increase in the number of tooth colored restorations "white fillings" placed in recent years. An increased demand from the public for more aesthetic dental restorations causes a potential problem for forensic dentists who may find the fillings difficult to identify and hence include in postmortem odontograms. This has implications for the accuracy of dental identifications, particularly in situations where limited time is available for postmortem identification, e.g., mass casualty incidents. A new method for the detection of composite restorations is presented. Quantitative Light-induced Fluorescence (QLF) is a technique currently employed to detect small changes in enamel mineral content. An experiment was conducted to determine if the technique would afford a greater degree of contrast between composite and enamel and thus enable the accuracy of composite identification in enamel. Twenty-four previously extracted human premolars were gently cleaned with pumice and wet-and-dry paper. Twelve were subsequently randomly selected and restored on their buccal surfaces with Spectrum (a composite) following manufacturer's instructions. No attempt was made to color match the teeth and all were filled with shade B3. Twelve teeth were left unrestored. QLF and normal white light images were taken of both restored and non-restored surfaces with teeth wet and then dried. Ten forensic dentists were asked on two separate occasions (one month between each attempt) to indicate whether or not they thought the surface was: a) restored or b) unrestored. Results indicate that forensic dentists detected a significantly higher proportion (p<0.005) of filled surfaces with QLF.

Autopsy↗