3D Bitemark Analysis in Forensic Odontology Utilizing a Smartphone Camera and Open-Source Monoscopic Photogrammetry Surface Scanning

Abstract Bitemark analysis is a challenging procedure in the field of criminal case investigation. The unique characteristics of dentition are used to find the best match between the existing patterned injury and the suspected perpetrator in bitemark identification. Bitemark analysis accuracy can be influenced by various factors, including biting pressure, tooth morphology, skin elasticity, dental cast duplication, timing, and image quality. This review article discusses the potential of a smartphone camera as an alternative method for 3D bitemark analysis. Bitemark evidence on human skin and food should be immediately recorded or duplicated to retrieve long-lasting proof, allowing for a sufficient examination period. Various studies utilizing two-dimensional (2D) and three-dimensional (3D) technologies have been developed to obtain an adequate bitemark analysis. 3D imaging technology provides accurate and precise analysis. However, the currently available method using an intraoral scanner (IOS) requires high-cost specialized equipment and a well-trained operator. The numerous advantages of monoscopic photogrammetry may lead to a novel method of 3D bitemark analysis in forensic odontology. Smartphone cameras and monoscopic photogrammetry methodology could lead to a novel method of 3D bitemark analysis with an efficient cost and readily available equipment.

A systematic review of 3D scanners and computer assisted analyzes of bite marks: searching for improved analysis methods during the Covid-19 pandemic.

The global Covid-19 pandemic has forced forensic dentists to improve infection control methods. This search investigated the practical utilization of different 3D scanners to record and to analyze bite marks in the skin- and inanimate objects with this aim in mind. A systematic review of the literature using keywords like "human bite mark", "bite mark analyzes", "3D analyzes", "3D scanning", "forensic odontology", and "forensic dentistry" was performed in three scientific databases: MEDLINEOvid®, Pubmed® and Google Scholar. The initial search yielded 263 full-text articles, of which 15 were considered eligible and current within the last 10 years. 3D scanners and computer-assisted human bite mark analyzes showed potential advantages and can be effectively used in forensic odontology on skin and inanimate objects. These technologies minimize the number of people being exposed to pathogens, simplify the chain of evidence, facilitate immediate information exchange between the team members and enable the virtual presentation of the expert witnesses in a court of law.

Three-dimensional analysis of bitemarks: A validation study using an intraoral scanner.

Conservation of the three-dimensional aspect of bitemarks optimizes their analysis. Although bitemarks could be recorded with a surface scanner, in clinical dentistry, intraoral scanners are used as an alternative to conventional dental impressions. Here we assess the reproducibility and the reliability of a three-dimensional bitemark analysis protocol using an intraoral scanner. Twenty-seven volunteers bit on different materials: dental wax, hard cheese, chocolate and apple. Then, bitemarks and dentitions were scanned with the PlanMeca® Emerald intraoral scanner and the scans obtained were exported into the mesh comparison software, CloudCompare®, which can generate overlays automatically. For this purpose, dentitions were aligned and compared with the indentations. The meshing and non-meshing areas were visualized using a colorimetric scale. First, the same blinded observer compared the bitten materials by analyzing 256 meshing areas for each. Secondly, comparisons of bitemarks from wax were analyzed in a randomized blinded study involving four observers (dentist, dental student, forensic scientist and police officer) and predictive values were calculated. The wax support obtained the best result and apple the worst. The rate of correct classifications was high and misclassification was rare. For the all observers, negative predictive values were near 100%. Positive predictive values were more variable. Moreover, the work clearly highlighted the importance of experience in odontology.

How best to approach these acute hand infections.

Antimicrobial therapy is not straightforward with the 4 infectious conditions reviewed here. Combination therapy at the start must usually be tailored once an organism is known.

Tri-dimensional pattern analysis of foodstuff bitemarks - A pilot study of tomographic database.

The analysis of bitemarks has been mostly done through analogical methods. The advent of current technologies brings new and more reliable tools for analyzing evidence. Bitemarks can now be turned into more consistent evidence by using a digital tridimensional (3D) analysis. The aim of this study is to propose a reliable, accurate and monitorized approach of 3D bitemark analysis. 12 cranium Cone Beam Computed Tomographic (CBCT) files were randomly selected from a clinical database (Coimbra Hospital and University Center/Faculty of Medicine of the University of Coimbra). The individuals were recalled to bite an apple (golden delicious 65/80) immediately subjected to a CBCT scan. The 3D rendering of every bitemark was compared with the 3D upper dental arches obtained from the CBCT cranium scans of the simulated suspects. The research team was composed by 5 elements. The matching process consists of corresponding landmark points, in both the bitemark and the suspects' dentition (upper dental arch). 144 comparisons were obtained. The Kappa statistics analysis was performed. Cohen's Kappa values were obtained between 0,690 and 0,910. Fleiss Kappa obtained a value of 0,767. The Friedman's test was performed and the normality assumption was not verified (p>0,05). A non-destructive protocol of bitemark study by 3D analysis of tomographic volumes was presented. The statistic analysis supports its accuracy and reliability. This experimental study opens doors to a future where bitemark analysis could be done through software that searches for matching dentitions in a CBCT database.

Analysis of Intercanine Distance and Dimensional Changes in Bite Marks on Foodstuffs Using Cone Beam Computed Tomography.

Bite marks on foodstuff at the crime scene provide a 3-dimensional imprint of the suspect's dentition. The bite mark analysis can provide useful evidences, leading to the inclusion or exclusion of the individual under investigation. This study was designed to assess bite marks on various common foodstuffs (chocolate, apple, chewing gum, cheese) for different time intervals using cone beam computed tomography (CBCT) to evaluate the dimensional changes in the foodstuffs. Analysis of variance test was used to compare the bite marks measured using CBCT in maxillary and mandibular arches with significance set at P < 0.05. The results show that teeth can transfer their characteristics to the bitten foodstuffs. The highest accuracy for comparative bite mark analysis was observed in chocolate followed by cheese, chewing gum, and apple. The CBCT-assisted analysis of bite marks is a nondestructive, accurate, and efficient method. The CBCT documentation has no distortion artifacts, and subsequent analysis in 3-dimensional space is possible.

Three-dimensional imaging of human cutaneous forearm bite marks in human volunteers over a 4 day period.

INTRODUCTION: Human bite marks are often sustained during sexual, domestic or child abuse. Currently, analysis of these marks involves digital photography techniques along with an expert forensic odontologist opinion. Photographs often focus closely on the bite mark and give little context to the anatomical location of the injury. Due to variation in camera models and expertise of the photographer, photograph quality can affect its interpretation. Additionally, it can sometimes be days between injury and examination, allowing the injury pattern and colour to alter, making it harder to analyse. AIM: To investigate if a 3D imaging technique, creating a time-lapse image of a bite mark in three dimensions, can provide context to the injury in terms of nature and location, and also allow analysis of the change in appearance of a bite mark over time. METHOD: Participants had an experimental bite mark produced on their forearm by dental casts mounted on a dental articulator. The forearms were photographed immediately following the bite, and at intervals of 3, 6, 24, 48, 72 and 96 h. A DI3D(®) (Dimensional Imaging 3D) photogrammetry system and Autodesk Maya 2015(®) software was used to create a 3D animation from the images obtained. The clearest, long lasting bite mark injuries were selected for animation, enabling the 3D imaging technique to be used optimally. RESULTS: 3D time-lapse animations were successfully created with the ability to be viewed on most electronic devices. With further refinement this technique could be valuable in a number of areas. We anticipate animations produced in this way to have significant benefit to the presentation of photographic evidence in a court setting, and in age estimation of injuries.

[Effectiveness assessment of 3-D cone beam CT used in human bite marks identification].

The present study was aimed to use the 3-D cone beam CT (CBCT) as a new method in human bite marks identification which was carried out in experimental pigskin to assess its effectiveness in our laboratory. Bite marks were digital photographed according to American Board of Forensic Odontology (ABFO) guidelines. In this study, the data of the suspect's dental casts were collected by scanning in two ways: one was after plate scanning, in which the comparison overlays were generated by Adobe Photoshop 8.0 software; the other was by CBCT, which generated comparison overlays automatically. The bite marks were blind identified with the two kinds of data of the suspect's dental casts respectively. ROC curve was used to analyze the sensitivity, specificity, and 95% confidence interval. The results showed that CBCT method got a larger area under the ROC curve: 0.784 (SE = 0.074, 95% CI = 0.639-0.929), and got a very high specificity (specificity 98.7%, 95% CI = 94.5%-99.8%). Thus, this study illustrates that the CBCT used in bite mark identification is an effective and accurate tool and has stronger ability to exclude suspects compared with the conventional method, but the comparison process needs further study to enhance its effectiveness in bite mark identification.

Analysis of bite marks in foodstuffs by computer tomography (cone beam CT)--3D reconstruction.

The use of three-dimensional (3D) analysis of forensic evidence is highlighted in comparison with traditional methods. This three-dimensional analysis is based on the registration of the surface from a bitten object. The authors propose to use Cone Beam Computed Tomography (CBCT), which is used in dental practice, in order to study the surface and interior of bitten objects and dental casts of suspects. In this study, CBCT is applied to the analysis of bite marks in foodstuffs, which may be found in a forensic case scenario. 6 different types of foodstuffs were used: chocolate, cheese, apple, chewing gum, pizza and tart (flaky pastry and custard). The food was bitten into and dental casts of the possible suspects were made. The dental casts and bitten objects were registered using an x-ray source and the CBCT equipment iCAT® (Pennsylvania, EUA). The software InVivo5® (Anatomage Inc, EUA) was used to visualize and analyze the tomographic slices and 3D reconstructions of the objects. For each material an estimate of its density was assessed by two methods: HU values and specific gravity. All the used materials were successfully reconstructed as good quality 3D images. The relative densities of the materials in study were compared. Amongst the foodstuffs, the chocolate had the highest density (median value 100.5 HU and 1,36 g/cm(3)), while the pizza showed to have the lowest (median value -775 HU and 0,39 g/cm(3)), on both scales. Through tomographic slices and three-dimensional reconstructions it was possible to perform the metric analysis of the bite marks in all the foodstuffs, except for the pizza. These measurements could also be obtained from the dental casts. The depth of the bite mark was also successfully determined in all the foodstuffs except for the pizza. Cone Beam Computed Tomography has the potential to become an important tool for forensic sciences, namely for the registration and analysis of bite marks in foodstuffs that may be found in a crime scene.

Treatment of infected clench-fist human bite wounds in the area of metacarpophalangeal joints.

We reviewed the cases of 221 patients with infected clench-fist human bite wounds in the area of metacarpophalangeal joints. If the joint's capsule was not violated (79 patients), the wound was debrided and irrigated using an antiseptic solution. The would was drained with microirrigators and closed primarily. A second group of 53 patients in whom the joint had been violated but without osseous or articular involvement were treated with debridement, irrigation, drainage, and skin closure. A third group with articular and/or bone destruction (89 patients) was treated the same way as group 2 with the addition of a distraction device to fix and "unload" the joint. In the first group, 71 patients had excellent results and 2 had satisfactory results (6 were lost to follow-up examination). In the second group, 38 patients had excellent results, 7 patients had satisfactory results, and 2 had unsatisfactory results (six patients were lost to follow-up examination). In the third group, 39 patients had excellent results, 24 had satisfactory results, and 10 had unsatisfactory results (16 patients were lost to follow-up examination).

Image editing and computer assisted bitemark analysis: a case report.

Bitemark evidence in a homicide usually involves a perpetrator biting the victim prior to or around the time of death. This paper presents a case in which a homicide victim bit his assailant. A suspect taken into custody was found to have what appeared to be a human bitemark on the proximal phalanx of his right thumb. Scale photographs of this injury were obtained and compared to the dentition of the decreased using digitized computer images for superimposition. Three different approaches for comparison with the bitemark photograph were utilized: comparison with radiographs of amalgam-filled impressions of dental casts, a transparent overlay technique and comparison with photographs of a simulated bitemark inked onto the hand of a volunteer. A review of these techniques as they apply to computerized bitemark analysis is presented.

Computerized axial tomography as an aid in bite mark analysis: a case report.

A case is presented to demonstrate the use of computerized axial tomography (CAT) to develop precise registration of incisal edges for comparison to bite marks. Emphasis is drawn to the availability of CAT Scanning equipment and the importance of understanding its use as an adjunct or alternative to already accepted methods of incisal registration.

Osteomyelitis and septic arthritis of the hand following human bites.

The spectrum of radiographic abnormalities accompanying bone and joint infection that results from human bites of the hand is presented in an analysis of 13 patients. Features include mono-articular involvement, predilection for a metacarpophalangeal joint, soft tissue swelling, joint space narrowing, bone erosions and periostitis. Magnification techniques may be required for early and accurate diagnosis.