Computer comparison of bitemark patterns in identical twins

A comparative study of sagittal dental relationship using digital method of bite mark evaluation

Introduction:

Intercuspation of teeth depends on position of teeth and jaws. Bite mark is the resultant of the intercuspation of teeth produced by an individual.

Aims and Objective:

Comparative evaluation of bite marks in Angle's Class I, II, and III sagittal occlusion.

Materials and Methods:

Three groups as per Angle's classification-Class I, Class II, and Class III relation were taken. Each group comprised 30 samples each. The dental casts were scanned to create digital images. “IC Measure” software was used to determine the angular and linear measurements on scanned images of study model after calibration. Internal angles of odontometric triangle, intercanine width, shape of the arch, size, and shape of the individual teeth was recorded and subjected to the statistical analysis.

Results:

All incisors had rectangular and canine had triangular shape. Bilateral maxillary lateral incisors and mandibular left central incisor were significantly small in size for Class III. Square arch form was found more commonly in Class III and ovoid arch form in Class I and Class II occlusion. Intercanine width was insignificant among all occlusions. All the angles of the odontometric triangle in the maxillary and mandibular arches were significant for Class III.

Conclusion:

Class III occlusion individuals were distinct for shape of the arch and angles of maxillary and mandibular odontometric triangle. The quantified values of odontometric triangle can be utilized for the identification of Class III individuals.

Three-dimensional palatal anatomic characteristics' correlation with dermatoglyphic heterogeneity in Angle malocclusions

OBJECTIVES

To assess correlation of dermatoglyphic (DG) pattern with quantitative palatal anatomic parameters measured using three-dimensional (3D) scanning of dental casts and to explore the possibility of utilizing these to predict future occurrence of malocclusion.

MATERIALS AND METHODS

Pretreatment casts of 477 Saudi Arabian patients were divided into Class I, II, and III malocclusion groups. Fingerprints were recorded for all hand digits using a digital biometric device. Maxillary arch analysis was accomplished including intercanine, intermolar distance, palatal height, and palatal area. The results were statistically analyzed.

RESULTS

The mean surface area of the palate was highest in Class II malocclusion. The DG pattern was not significantly associated with the type of malocclusion, except in the instance of the double loop characteristic (P = .05). There was a strong correlation, however, between DG characteristics like simple arch, loop, and double loop and palatal dimensions (intercanine, intermolar distance, and palatal height). Heterogeneity of DG pattern could be reliably used to predict palatal dimensions. Logistic regression revealed that only tented arch, symmetrical, spiral DG patterns and palatal area were significant but weak predictors of Angle malocclusion (P < .05).

CONCLUSIONS

A novel correlation of DG pattern with 3D palatal anatomic characteristics was assessed in different Angle malocclusion classes. Few of the DG characteristics and palatal dimensions showed significant correlations. However, only some of these were significant predictors of Angle malocclusion.

Three-dimensional analysis of the uniqueness of the anterior dentition in orthodontically treated patients and twins

Dental uniqueness can be proven if no perfect match in pair-wise morphological comparisons of human dentitions is detected. Establishing these comparisons in a worldwide random population is practically unfeasible due to the need for a large and representative sample size. Sample stratification is an option to reduce sample size. The present study investigated the uniqueness of the human dentition in randomly selected subjects (Group 1), orthodontically treated patients (Group 2), twins (Group 3), and orthodontically treated twins (Group 4) in comparison with a threshold control sample of identical dentitions (Group 5). The samples consisted of digital cast files (DCF) obtained through extraoral 3D scanning. A total of 2.013 pair-wise morphological comparisons were performed (Group 1 n=110, Group 2 n=1.711, Group 3 n=172, Group 4 n=10, Group 5 n=10) with Geomagic Studio^® (3D Systems^®, Rock Hill, SC, USA) software package. Comparisons within groups were performed quantifying the morphological differences between DCF in Euclidean distances. Comparisons between groups were established applying One-way ANOVA. To ensure fair comparisons a post-hoc Power Analysis was performed. ROC analysis was applied to distinguish unique from non-unique dentures. Identical DCF were not detected within the experimental groups (from 1 to 4). The most similar DCF had Euclidian distance of 5.19mm in Group 1, 2.06mm in Group 2, 2.03mm in Group 3, and 1.88mm in Group 4. Groups 2 and 3 were statistically different from Group 5 (p<0.05). Statistically significant difference between Group 4 and 5 revealed to be possible including more pair-wise comparisons in both groups. The ROC analysis revealed sensitivity rate of 80% and specificity between 66.7% and 81.6%. Evidence to sustain the uniqueness of the human dentition in random and stratified populations was observed in the present study. Further studies testing the influence of the quantity of tooth material on morphological difference between dentitions and its impact on uniqueness remain necessary.

Uniqueness of the anterior dentition three-dimensionally assessed for forensic bitemark analysis

The uniqueness of the human dentition (UHD) is an important concept in the comparative process in bitemark analysis. During this analysis, the incisal edges of the suspects' teeth are matched with the bitemarks collected from the victim's body or crime scenes. Despite playing an essential part to exclude suspects, the UHD contained in the involved incisal tooth edges remains an assumption on bitemark level. The present study was aimed, first, to investigate three-dimensionally (3D) the UHD within different quantities of dental material from the incisal edges; second, to test these outcomes in a bidimensional (2D) simulation. Four-hundred forty-five dental casts were collected to compose 4 study groups: I - randomly-selected subjects, II - orthodontically treated subjects, III - twins and IV - orthodontically treated twins. Additionally, 20 dental casts were included to create threshold groups on subjects from whom the dental impressions were taken at 2 different moments (Group V). All the dental casts were digitalized with an automated motion device (XCAD 3D^® (XCADCAM Technology^®, São Paulo, SP, Brazil). The digital cast files (DCF) were integrated in Geomagic Studio^® (3D Systems^®, Rock Hill, SC, USA) software package (GS) for cropping, automated superimposition and pair-wise comparisons. All the DCF were cropped remaining 3 mm (part 1), 2 mm (part 2) and 1 mm (part 3) from the incisal edges of the anterior teeth. For a 2D validation, slices of 1 mm, not including incisal edges (part 4), were also cropped. These procedures were repeated in Group V, creating specific thresholds for each of the study parts. The 4 study groups were compared with its respective threshold using ANOVA test with statistical significance of 5%. Groups I, II and III did not differ from the corresponding threshold (Group V) in all study parts (p > 0.05). Scientific evidence to support the UHD was not observed in the current study. Bitemark analysis should not be disregarded but considered carefully when the suspects present similar dental alignment and morphology, such as in orthodontically treated subjects and twins, respectively.

Three-dimensional validation of the impact of the quantity of teeth or tooth parts on the morphological difference between twin dentitions

BACKGROUND

The number of teeth involved in cases of bite-mark analysis is generally fewer in comparison to the number of teeth available for cases of dental identification. This decreases the amount of information available and can hamper the distinction between bite suspects. The opposite is true in cases of dental identification and the assumption is that more teeth contribute to a higher degree of specificity and the possibility of identification in these cases. Despite being broadly accepted in forensic dentistry, this hypothesis has never been scientifically tested.

OBJECTIVE

The present study aims to assess the impact of the quantity of teeth or tooth parts on morphological differences in twin dentitions.

MATERIAL AND METHODS

A sample of 344 dental casts collected from 86 pairs of twins was used. The dental casts were digitized using an automated motion device (XCAD 3D® (XCADCAM Technology®, São Paulo, SP, Brazil) and were imported as three-dimensional dental model images (3D-DMI) in Geomagic Studio® (3D Systems®, Rock Hill, SC, USA) software package. Sub samples were established based on the quantity of teeth and tooth parts studied. Pair wise morphological comparisons between the corresponding twin siblings were established and quantified.

RESULTS

Increasing the quantity of teeth and tooth parts resulted in an increase of morphological difference between twin dentitions. More evident differences were observed comparing anterior vs. entire dentitions (p < 0.05) and complete vs. partial anterior dentitions (p < 0.05).

CONCLUSION

Dental identifications and bite-mark analysis must include all the possibly related dental information to reach optimal comparison outcomes.

Dentistry to the rescue of missing children: A review

Today's society is becoming increasingly unsafe for children: we frequently hear about new incidents of missing children, which lead to emotional trauma for the loved ones and expose systemic failures of law and order. Parents can take extra precautions to ensure the safety of their children by educating them about ways to protect themselves and keep important records of the child such as updated color photographs, fingerprints, deoxyribonucleic acid (DNA) samples, etc., handy. However, in spite of all efforts, the problem of missing children still remains. Developments in the field of dentistry have empowered dentists with various tools and techniques to play a pivotal role in tracing a missing child. One such tool is Toothprints, a patented arch-shaped thermoplastic dental impression wafer developed by Dr. David Tesini, a paediatric dentist from Massachusetts. Toothprints enables a unique identification of the missing children not only through the bite impression but also through salivary DNA. Besides the use of Toothprints, a dentist can assist investigating agencies in identifying the missing children in multiple ways, including postmortem dental profiling, labeled dental fixtures, DNA extraction from teeth, and serial number engraving on the children's teeth. More importantly, all these tools cause minimal inconvenience to the individual, making a dentist's role in tracking a missing child even more significant. Thus, the simple discipline of maintaining timely dental records with the help of their dentists can save potential hassles for the parents in the future.

The uniqueness of the human dentition as forensic evidence: a systematic review on the technological methodology

The uniqueness of human dentition is routinely approached as identification evidence in forensic odontology. Specifically in bitemark and human identification cases, positive identifications are obtained under the hypothesis that two individuals do not have the same dental features. The present study compiles methodological information from articles on the uniqueness of human dentition to support investigations into the mentioned hypothesis. In April 2014, three electronic library databases (SciELO®, MEDLINE®/PubMed®, and LILACS®) were systematically searched. In parallel, reference lists of relevant studies were also screened. From the obtained articles (n = 1235), 13 full-text articles were considered eligible. They were examined according to the studied parameters: the sample size, the number of examined teeth, the registration technique for data collection, the methods for data analysis, and the study outcomes. Six combinations of studied data were detected: (1) dental shape, size, angulation, and position (n = 1); (2) dental shape, size, and angulation (n = 4); (3) dental shape and size (n = 5); (4) dental angulation and position (n = 2); (5) dental shape and angulation (n = 1); and (6) dental shape (n = 1). The sample size ranged between 10 and 1099 human dentitions. Ten articles examined the six anterior teeth, while three articles examined more teeth. Four articles exclusively addressed three-dimensional (3D) data registration, while six articles used two-dimensional (2D) imaging. In three articles, both imaging registrations were combined. Most articles (n = 9) explored the data using landmark placement. The other articles (n = 4) comprised digital comparison of superimposed dental contours. Although there were large methodological variations within the investigated articles, the uniqueness of human dentition remains unproved.

Identification of a person with the help of bite mark analysis

Forensic dentistry is an essential part of Forensic science, mainly involves the identification of an assailant by comparing a record of their dentition (set of teeth) with a record of a bite mark left on a victim. Other uses in law for dentists include the identification of human remains, medico-legal assessment of trauma to oral tissues, and testimony about dental malpractice. While the practice of human identification is well established, validated and proven to be accurate, the practice of bite mark analysis is less well accepted. The principle of identifying an injury as a bite mark is complex and, depending on severity and anatomical location, highly subjective. Following the identification of an injury as a bite mark, the comparison of the pattern produced to a suspect's dentition is even more contentious and an area of great debate within contemporary odontological practice. Like fingerprints and DNA, bite marks are unique to an individual - such as distance and angles between teeth, missing teeth, fillings and dental work. This type of impression evidence can be left in the skin of a victim and also can be in food, chewing gum and other miscellaneous items such as pens and pencils. The advent of DNA analysis and its recovery from bite marks has offered an objective method of bite mark analysis.

Orthodontic surgery and professional liability: the homozygote twin case

A professional liability lawsuit of an orthodontic case is presented through its medico-legal assessment. The patient underwent an orthodontic treatment combined with several maxillo-facial surgical interventions. Several temporomandibular joint complications followed, plus he was unhappy with aesthetic results and modifications to his facial features. He wanted to verify from a medico-legal point of view the treatment received as he believed something was not done lege artis. The result of the orthodontic assessment was that there were no indications for such surgical interventions, along with other professional negligence: no psychological support given and no indications as to the aesthetic results postsurgery. It was decided to carry out an orthodontic assessment also on his homozygote twin brother, who was discovered to have the same malocclusion. His medico-legal assessment did not substitute the evidence obtained from the deceased, but gave added weight to the final technical conclusion.

Validity of a dichotomous expert response in bitemark analysis using 3-D technology

Despite efforts to quantify bitemark evidence, comparison procedures remain subjective and yield different degrees of certainty. Our aim was to study the effectiveness of a comparison procedure requiring a dichotomous response by the expert. We compared overlays from 3-D images of dental casts and bite impressions, obtained using DentalPrint(©) software. Receiver operating characteristic (ROC) analysis was performed on the results of 104 comparisons, finding an area under the ROC curve of 0.955 (standard error=0.029; 95% CI, 0.896-0.986), sensitivity of 92.3% (95% CI, 74.8-98.8) and specificity of 98.7% (95% CI, 93.0-99.8). According to these findings, this bitemark analysis procedure is highly accurate, although study limitations are discussed, placing these results in context. The main advantage of the dichotomous decision model is that it can be more easily understood, facilitating course of justice. Further research is warranted to explore the potential of this approach as an alternative to diagnostic decisions based on certainty levels.

The Uniqueness of the Human Anterior Dentition: A Geometric Morphometric Analysis

The analysis of bitemarks has a significant bearing on forensic odontology and has attracted an increasingly sophisticated array of techniques in its evaluation. Two postulates underlie all bitemark analyses: firstly, that the characteristics of the anterior teeth involved in the bite are unique, and secondly, that this uniqueness is accurately recorded in the material bitten. Here, we investigate the question of the uniqueness of the anterior dentition. To do this, we use geometric morphometric techniques based on landmark and semilandmark data. The incisor and canine occlusal surfaces of 50 randomly selected orthodontic casts of young individuals (17-20 years) of both sexes form the material for this study. We analyzed the sizes of these teeth by means of landmark and semilandmark analysis to calculate Procrustes distances between tooth outlines. In order to analyze shape variation among individuals, we carried out principal components analyses on the partial warp scores. These are derived from Partial Procrustes coordinates aligned by means of thin-plate spline decomposition based on the bending energy matrix. The results indicate that there is no sexual dimorphism in the shape of the upper or lower arches. Plots of centroid size and first relative warps show less superposition among individuals than in shape analysis. This means that, when the size and shape are considered together, the difference between arches increases. Procrustes superimposition between the two individuals located most closely (0.0444) and the two most separated (0.1567) along the first axis of relative warp analyses show that individuals are not only differentiated by the relative position of their teeth but also by their arch shape. In conclusion, it appears that the incisal surfaces of the anterior dentition are in fact unique.

A Technique to Capture, Analyze, and Quantify Anterior Teeth Rotations for Application in Court Cases Involving Tooth Marks

Anterior teeth within the human dentition have a specific numerical rotation value. Bite marks show an array of angled indentations, abrasions, microlacerations, and contusions. These marks generally represent the incisal surfaces of the suspect's dentition reflecting the rotation values of the teeth in the dental arch. This study described a method for capturing and analyzing anterior dental rotations. The rotations of individual anterior teeth within the study population were categorized as common, uncommon, and very uncommon according to Allen's classification. In the absence of a large number of incisal patterns present in a bite mark, a single but heavily weighted tooth rotation could be of equal discriminatory potential to several common rotation values. No prevalence studies quantifying individual tooth rotations are available. The measurement of each individual tooth rotation together with its individual discrimination potential will enhance the evaluation of the concordant features observed in bite marks.

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.

The scientific basis for human bitemark analyses--a critical review

This article presents a discussion of the scientific basis for human bitemark analyses. Using a review of the literature, the major areas of contention within the field are assessed: including the accuracy of bitemarks on skin, the uniqueness of the human dentition, and analytical techniques. The review revealed a lack of valid evidence to support many of the assumptions made by forensic dentists during bitemark comparisons. The new level of judicial scrutiny of such scientific evidence is likely to emphasise this lack of knowledge upon which bitemark analysis relies. The authors call for a more scientific and evidence-based approach to forensic dental research.

Mirror-image dental fusion and discordance in monozygotic twins

A pair of monozygotic twins had similar but not identical dental anomalies. One twin had fusion of deciduous mandibular lateral incisor and canine on the left, with normal dentition on the right; the co-twin had right mandibular incisor/canine fusion, with aplasia of the lateral incisor on the left. These findings are discussed in the context of the related phenomena of situs inversus, mirror-imaging in twins, and gradients of severity of anomalies in the four copies of the mandibular developmental dental field.

Mirror imaging in twins: biological polarization--an evolving hypothesis

This study examined sleep patterns in twins, paying special attention to the mirroring phenomenon. Concordance and discordance of sleep related patterns (parasomnias) in a group of 27 monozygotic (MZ) mirror image twins were compared to sleep patterns in a group of 53 MZ non-mirror image twins and a group of 24 dizygotic (DZ) twin pairs. Sleep patterns had the lowest concordance among MZ mirror twins. "Mirroring" was observed not only in facial features but also in some physiological patterns such as sleep and sleep deviations. These facts suggest that mirroring in MZ twins is not merely a superficial epiphenomenon, but a reflection of a biological polarization. Biological polarization in this context is a descriptive term emphasizing the role of biological (physiological, biochemical or even genetic) versus psychological or environmental factors causing not only mirror body image but opposite tendencies in the development of personality, professional and sex orientation and, most importantly, the opposite presentation of pathology.

The use of twins in dentofacial genetic research

A literature review is given on the different results obtained with twin and family studies in relationship to the development and structure of the dentofacial complex. Recent advances in twin and family studies are mentioned. Attention is focused on functional components considered to be of primary importance in craniofacial growth.

Twin studies in craniofacial genetics: a review

A review of the literature on twin studies in craniofacial genetics is presented. The following areas are particularly dealt with: tooth form and size, tooth formation and eruption, dental arch and occlusion, facial form and size, and cleft lip and palate.