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.

Stereophotogrammetric head shape assessment in neonates is feasible and can identify distinct differences between term-born and very preterm infants at term equivalent age.

The development of head shape and volume may reflect neurodevelopmental outcome and therefore is of paramount importance in neonatal care. Here, we compare head morphology in 25 very preterm infants with a birth weight of below 1500 g and / or a gestational age (GA) before 32 completed weeks to 25 term infants with a GA of 37-42 weeks at term equivalent age (TEA) and identify possible risk factors for non-synostotic head shape deformities. For three-dimensional head assessments, a portable stereophotogrammetric device was used. The most common and distinct head shape deformity in preterm infants was dolichocephaly. Severity of dolichocephaly correlated with GA and body weight at TEA but not with other factors such as neonatal morbidity, sex or total duration of respiratory support. Head circumference (HC) and cranial volume (CV) were not significantly different between the preterm and term infant group. Digitally measured HC and the CV significantly correlated even in infants with head shape deformities. Our study shows that stereophotogrammetric head assessment is feasible in all preterm and term infants and provides valuable information on volumetry and comprehensive head shape characteristics. In a small sample of preterm infants, body weight at TEA was identified as a specific risk factor for the development of dolichocephaly.

Evaluation of a Novel Three-Dimensional Wound Measurement Device for Assessment of Diabetic Foot Ulcers.

Objective: The initial wound measurement and regular monitoring of diabetic foot ulcers (DFU) is critical to assess treatment response. There is no standardized, universally accepted, quick, reliable, and quantitative assessment method to characterize DFU. To address this need, a novel topographic imaging system has been developed. Our study aims at assessing the reliability and practicality of the WoundVue® camera technology in the assessment of DFU. Approach: The WoundVue system is a prototype device. It consists of two infrared cameras and an infrared projector, and it is able to produce a three-dimensional (3D) reconstruction of the wound structure. Fifty-seven diabetic foot wounds from patients seen in a multidisciplinary foot clinic were photographed from two different angles and distances by using the WoundVue camera. Wound area, volume, and maximum depth were measured for assessment of reliability. Thirty-one of these wounds also had area calculated by using the established Visitrak™ system, and a correlation between the area obtained by using both systems was assessed. Results: WoundVue images analysis showed excellent agreement for area (intraclass correlation coefficient [ICC]: 0.995), volume (ICC: 0.988), and maximum depth (ICC: 0.984). Good agreement was found for area measurement by using the WoundVue camera and Visitrak system (ICC: 0.842). The average percentage differences between measures obtained by using the WoundVue from different angles for assessment of different sizes and shapes of wounds were 2.9% (95% confidence interval [CI]: 0.3-5.4), 12.9% (95% CI: 9.6-35.7), and 6.2% (95% CI: 2.3-14.7) for area, maximum depth, and volume, respectively. Innovation: This is the first human trial evaluating this novel 3D wound measurement device. Conclusion: The WoundVue system is capable of recreating a 3D model of DFU and produces consistent data. Digital images are ideal for monitoring wounds over time, and the WoundVue camera has the potential to be a valuable adjunct in diabetic foot wound care.

Documenting a cultural landscape using point-cloud 3d models obtained with geomatic integration techniques. The case of the El Encín atomic garden, Madrid (Spain).

A country's cultural landscapes are an important part of its heritage. The growing need to identify, catalogue and preserve these resources has led to a rapid change in the management and inventorying of heritage in general and of cultural landscapes in particular. The main aim of this work is to develop and apply an updated and integrated methodology for capturing and processing geo-information for the digital documentation of cultural heritage. The proposed case study is the atomic garden in the Finca El Encín (Madrid), a singular space with unique biogeographical features created over 60 years ago. The results of the case study validate the method, consisting of an unmanned aerial platform equipped with sensors to obtain point clouds and aerial images in conjunction with point clouds and images captured with a terrestrial laser scanner.

Experimental method for 3D reconstruction of Odonata wings (methodology and dataset).

Insect wings are highly evolved structures with aerodynamic and structural properties that are not fully understood or systematically modeled. Most species in the insect order Odonata have permanently deployed high aspect ratio wings. Odonata have been documented to exhibit extraordinary flight performance and a wide range of interesting flight behaviors that rely on agility and efficiency. The characteristic three-dimensional corrugated structures of these wings have been observed and modeled for a small number of species, with studies showing that corrugations can provide significant aerodynamic and structural advantages. Comprehensive museum collections are the most practical source of Odonata wing, despite the risk of adverse effects caused by dehydration and preservation of specimens. Museum specimens are not to be handled or damaged and are best left undisturbed in their display enclosures. We have undertaken a systematic process of scanning, modeling, and post-processing the wings of over 80 Odonata species using a novel and accurate method and apparatus we developed for this purpose. The method allows the samples to stay inside their glass cases if necessary and is non-destructive. The measurements taken have been validated against micro-computed tomography scanning and against similar-sized objects with measured dimensions. The resulting publicly available dataset will allow aeronautical analysis of Odonata aerodynamics and structures, the study of the evolution of functional structures, and research into insect ecology. The technique is useable for other orders of insects and other fragile samples.

Sources of variation in the 3dMDface and Vectra H1 3D facial imaging systems.

As technology advances and collaborations grow, our ability to finely quantify and explore morphological variation in 3D structures can enable important discoveries and insights into clinical, evolutionary, and genetic questions. However, it is critical to explore and understand the relative contribution of potential sources of error to the structures under study. In this study, we isolated the level of error in 3D facial images attributable to four sources, using the 3dMDface and Vectra H1 camera systems. When the two camera systems are used separately to image human participants, this analysis finds an upper bound of error potentially introduced by the use of the 3dMDface or Vectra H1 camera systems, in conjunction with the MeshMonk registration toolbox, at 0.44 mm and 0.40 mm, respectively. For studies using both camera systems, this upper bound increases to 0.85 mm, on average, and there are systematic differences in the representation of the eyelids, nostrils, and mouth by the two camera systems. Our results highlight the need for careful assessment of potential sources of error in 3D images, both in terms of magnitude and position, especially when dealing with very small measurements or performing many tests.

A Simple Standardized Three-Dimensional Anthropometry for the Periocular Region in a European Population.

BACKGROUND: The three-dimensional surface imaging system is becoming more common in plastic surgeries. However, few studies have assessed three-dimensional periocular structures and surgical outcomes. This study aimed to propose a standardized three-dimensional anthropometric protocol for the periocular region, investigate its precision and accuracy, and determine the three-dimensional periocular anthropometric norms for young Caucasians. METHODS: Thirty-nine healthy young Caucasians (78 eyes) were enrolled. Three-dimensional facial images were obtained with a VECTRA M3 stereophotogrammetry device. Thirty-eight measurements in periocular regions were obtained from these images. Every subject underwent facial surface capture twice to evaluate its precision. A paper ruler was applied to assess its accuracy. RESULTS: Sixty-three percent of measurements in linear distances, curvatures, angles, and indices were found to reach a statistically significant difference between sexes (p ≤ 0.05, respectively). Across all measurements, the average mean absolute difference was 0.29 mm in linear dimensions, 0.56 mm in curvatures, 1.67 degrees in angles, and 0.02 in indices. In relative error of magnitude, 18 percent of the measurements were determined excellent, 51 percent very good, 31 percent good, and none moderate. The mean value of the paper-ruler scale was 10.01 ± 0.05 mm, the mean absolute difference value 0.02 mm, and the relative error of magnitude 0.17 percent. CONCLUSIONS: This is the first study to propose a detailed and standardized three-dimensional anthropometric protocol for the periocular region and confirm its high precision and accuracy. The results provided novel metric data concerning young Caucasian periocular anthropometry and determined the variability between sexes.

Validation of two handheld devices against a non-portable three-dimensional surface scanner and assessment of potential use for intraoperative facial imaging.

BACKGROUND: The aim of this study was to compare accuracy and timing of two handheld, mobile three-dimensional surface imaging (3DSI) devices against an established non-portable medical imaging system, and to evaluate future intraoperative use for facial surgery. METHODS: Surface-to-Surface root mean square analysis was used to evaluate both a consumer device (Sense 3D) and a professional surface scanner (Artec Eva) against a reference imaging system (Vectra XT). Two assessors repeatedly 3D-imaged the facial region of an imaging phantom and 30 volunteers in two separate sessions. Using both mobile devices, intraoperative 3DSI of 10 rhinoplasty patients was compared with preoperative reference imaging. Intraclass Correlation Coefficient was calculated for repeated measurements. RESULTS: Artec Eva yielded mean deviations below 0.5 mm for the whole face and all subunits excluding the eye region. Sense 3D showed similar deviations for the whole face, but otherwise only in the central and lateral forehead unit and the medial cheek. Variability was low for both the non-portable Vectra XT and Artec Eva, whereas full-face assessment using Sense 3D resulted in high variability. When compared to the preoperative reference images, intraoperative rhinoplasty 3DSI revealed low deviations for Artec Eva and high deviations for Sense 3D. CONCLUSIONS: The 3D surfaces captured by Artec Eva showed a similarly desirable accuracy for facial imaging as Vectra XT reference images. This handheld device presents a suitable option for the objective documentation during rhinoplasty surgery. Sense 3D was unable to accurately capture complex facial surfaces and is therefore limited in its usefulness for intraoperative 3DSI.

Reliability of Periocular Anthropometry: A Comparison of Direct, 2-Dimensional, and 3-Dimensional Techniques.

BACKGROUND: Three-dimensional (3D) imaging has become increasingly popular in aesthetic surgery. However, few studies have emphasized its application in the periocular region. OBJECTIVE: To provide evidence supporting the reliability of generalizing periocular measurements obtained using caliper-derived direct anthropometry and 2-dimensional (2D) photogrammetry to 3D stereophotogrammetry. MATERIALS AND METHODS: Periocular surfaces were captured using a stereophotogrammetry system for 46 normal Caucasian individuals. Twenty-two periocular variables were directly, 2-dimensionally, and 3-dimensionally measured. Reliability of these measurements was evaluated and compared with each other. RESULTS: The results revealed that, for direct (intra-rater reliability only), 2D, and 3D anthropometry, overall intra-rater and inter-rater intraclass correlation coefficient estimates were 0.88, 0.99 and 0.97, and 0.98 and 0.92, respectively; mean absolute differences were 0.84 mm, 0.26 and 0.36 units, and 0.35 and 0.67 units, respectively; technical error of measurement (TEM) estimates were 0.85 mm, 0.25 and 0.36 units, and 0.32 and 0.65 units, respectively; relative error measurement estimates were 6.46%, 1.69% and 2.74%, and 1.67% and 5.11%, respectively; and relative TEM estimates were 6.25%, 1.62% and 2.78%, and 2.12% and 5.12%, respectively. CONCLUSION: Stereophotogrammetry and the authors' landmark location protocol yield very good reliability for a series of 2D and 3D measurements.

Microstomia: Aplicação da fotogrametria para mensurar a eficiência da órtese oral associada à terapia fonoaudiológica / Microstomy: Application of photogrammetry to measure the efficiency of oral orthosis associated with speech therapy

OBJETIVO: Esse estudo teve como propósito verificar, por meio da fotogrametria computadorizada, a eficácia do uso da órtese oral como auxiliar na terapia fonoaudiológica. MÉTODO: Após a documentação fotográfica, cada paciente foi submetido a terapia fonoaudiológica, por meio da terapia miofuncional orofacial, associada ao uso da órtese oral, confeccionada segundo Borges et al. (2011). Ao término do tratamento, foi realizado novo registro fotográfico, em seguida, a mensuração da dimensão vertical (distância entre lábio superior/inferior) e horizontal (distância entre comissuras direita/esquerda), com o uso do programa Corel Draw X3. RESULTADOS: As médias da abertura bucal aumentaram da avaliação inicial para a avaliação final, tendo aumentado 5,1 mm no sentido horizontal (67,3 mm para 72,4 mm) e 13,9 mm no sentido vertical (de 32,7 mm para 46,6 mm). Essas diferenças se revelam significativas para as avaliações (p <0,05). CONCLUSÃO: O uso da órtese oral associado a terapia fonoaudiológica demonstrou ser eficaz como mais um instrumento na prevenção da microstomia.

OBJECTIVES: The aim of this study was to through computerized photogrammetry, the efficacy of oral orthosis as an aid in speech therapy. METHODS: After the photographic documentation, each patient underwent speech therapy, through orofacial myofunctional therapy, associated with the use of an oral orthosis, made according to Borges et al. (2011). At the end of the treatment, a new photographic record was taken, then the vertical dimension measurement (distance between upper lip) and horizontal (distance between corners right/left), using the program Corel Draw X3. RESULTS: The mean mouth opening increased from the initial evaluation to the final evaluation, increasing 5.1 mm in the horizontal direction (67.3 mm to 72.4 mm) and 13.9 mm in the vertical direction (from 32.7 mm to 46.6 mm). These differences are significant for the evaluations (p<0.05). CONCLUSION: The use of oral orthosis associated with speech therapy proved to be effective as another tool in the prevention of microstomia.

Effectiveness of mat Pilates on postural alignment in the sagittal plane in school children: a randomized clinical trial

Abstract Aims: This study aimed to investigate the effectiveness of the mat Pilates method, an exercise program, on postural alignment in the sagittal plane among children aged between 8 and 12 years. Method: This study used a blind randomized controlled clinical trial, with a Pilates group (PG) and control group (CG) at the Early Childhood Education Institute. A total of 40 children were randomized, who have no prior knowledge of the Pilates method and no exercise training in the last six months. Mat Pilates exercises were administered twice a week for four months in 50-minute sessions. Postural alignment in the sagittal plane was assessed using photogrammetry. Results: There was no statistically significant difference between the groups post-intervention A significant difference was found in the following outcomes that represent an improvement in intragroup postural alignment: among the children in PG, in the right sagittal view in the vertical body alignment (p=0.019; effect size, ES = 0.70; standardize response mean, SRM = 0.57) and in the sagittal head angle (p=0.035; ES = 0.41; SRM = 0.51). Among the children in the CG, in the vertical alignment of the trunk in the left sagittal view (p= 0.016; ES = 0.50; SRM = 0.44). Conclusion: The effectiveness of Pilates on postural alignment in the sagittal plane among children aged between 8 and 12 years was not confirmed.

A Self-Assembly Portable Mobile Mapping System for Archeological Reconstruction Based on VSLAM-Photogrammetric Algorithm.

Three Dimensional (3D) models are widely used in clinical applications, geosciences, cultural heritage preservation, and engineering; this, together with new emerging needs such as building information modeling (BIM) develop new data capture techniques and devices with a low cost and reduced learning curve that allow for non-specialized users to employ it. This paper presents a simple, self-assembly device for 3D point clouds data capture with an estimated base price under €2500; furthermore, a workflow for the calculations is described that includes a Visual SLAM-photogrammetric threaded algorithm that has been implemented in C++. Another purpose of this work is to validate the proposed system in BIM working environments. To achieve it, in outdoor tests, several 3D point clouds were obtained and the coordinates of 40 points were obtained by means of this device, with data capture distances ranging between 5 to 20 m. Subsequently, those were compared to the coordinates of the same targets measured by a total station. The Euclidean average distance errors and root mean square errors (RMSEs) ranging between 12-46 mm and 8-33 mm respectively, depending on the data capture distance (5-20 m). Furthermore, the proposed system was compared with a commonly used photogrammetric methodology based on Agisoft Metashape software. The results obtained demonstrate that the proposed system satisfies (in each case) the tolerances of 'level 1' (51 mm) and 'level 2' (13 mm) for point cloud acquisition in urban design and historic documentation, according to the BIM Guide for 3D Imaging (U.S. General Services).

An analysis of body proportions in children with CHARGE syndrome using photogrammetric anthropometry.

BACKGROUND: Growth retardation is one of the main hallmarks of CHARGE syndrome (CS), yet little is known about the body proportions of these children. Knowledge of body proportions in CS may contribute to a better characterization of this syndrome. This knowledge is important when considering starting growth-stimulating therapy. METHODS: For this cross-sectional study, we selected 32 children with CS and a CHD7 mutation at the Dutch CHARGE Family Day in 2016 or 2017 and the International CHARGE conference in Orlando, Florida, in 2017. We used photogrammetric anthropometry-a measurement method based on digital photographs-to determine various body proportions. We compared these to measurements in 21 normally proportioned children with growth hormone deficiency, using independent-samples t test, Mann-Whitney U test, or chi-square test as appropriate. RESULTS: Children with CS appear to have a shorter trunk in proportion to their height, head length, and arm length. Children with CS also had smaller feet proportional to tibia length compared to controls. The change of body proportions with age was similar in children with CS and controls. CONCLUSION: Body proportions in children with CS are significantly different from those of normally proportioned controls, but a similar change of body proportions with age was noted for both groups.

Assessing the potential of photogrammetry to monitor feed intake of dairy cows.

We address the hypothesis that individual cow feed intake can be measured in commercial farms through the use of a photogrammetry method. Feed intake and feed efficiency have a significant economic value for the farmer. A common method for measuring feed mass in research is a feed mass weighing system, which is excessively expensive for commercial farms. However, feed mass can be estimated by its volume, which can be measured by photogrammetry. Photogrammetry applies cameras along the feed-lane, photographing the feed before and after the cow visits the feed-lane, and calculating the feed volume. In this study, the precision of estimating feed mass by its volume was tested by comparing measured mass and calculated volume of feed heaps. The following principal factors had an impact on the precision of this method: camera quality, lighting conditions, image resolution, number of images, and feed density. Under laboratory conditions, the feed mass estimation error was 0·483 kg for heaps up to 7 kg, while in the cowshed the estimation error was 1·32 kg for up to 40 kg. A complementary experiment showed that the natural feed compressibility causes about 85% of uncertainty in the mass estimation error.

A novel micro-photogrammetric instrument for visualizing in 3D small objects applied to the quantitative study of the dissolution behavior of a pharmaceutical dosage form.

The work presented here proposes an innovative approach to 3D chemical mapping of solid formulations by microphotogrammetry. We present details of a novel microphotogrammetry apparatus and the first results for the application of photogrammetry to the dissolution analysis of solid pharmaceutical dosage forms. Unlike other forms of optical imaging, microphotogrammetry allows a true 3D model to be constructed that includes direct observation of the sides of the sample rather than only top-down topographic imaging. Volume and structural changes are assessed quantitatively and related to chemical analysis by high performance liquid chromatography. The recently introduced method of chemical identification by dissolution analysis, or chemical imaging by dissolution analysis, is employed for the first time to obtain tomographic images of the dissolution process.

Feasibility and Accuracy of Noncontact Three-Dimensional Digitizers for Geometric Facial Defects: An In Vitro Comparison.

PURPOSE: To evaluate the feasibility and accuracy of noncontact three-dimensional (3D) digitization systems for capturing facial defects. MATERIALS AND METHODS: A stone model of a facial defect was digitized using high-accuracy industrial computed tomography as a reference scan. The model was also scanned using four different types of noncontact 3D digitizers: a laser beam light-sectioning technology with camera system and three different stereophotogrammetry systems. All 3D images were reconstructed with corresponding software and saved as standard triangulated language (STL) files. The 3D datasets were geometrically evaluated and compared to the reference data using 3D evaluation software. Kruskal-Wallis H tests were performed to assess differences in absolute 3D deviations between scans, with statistical significance defined as P < .05. RESULTS: The four noncontact 3D digitization systems were feasible for digitizing the facial defect model, although the median 3D deviation of the four digitizers varied. There was a significant difference in accuracy among the digitizers (P < .001). CONCLUSION: Digitization of facial defect models using various noncontact 3D digitizers appears to be feasible and is most accurate with laser beam light-sectioning technology. Further investigations assessing digitization of facial defects among patients are required to clinically verify the results of this study.

Evaluation of a portable low-budget three-dimensional stereophotogrammetry system for nasal analysis.

BACKGROUND: Three-dimensional (3D) photogrammetry has reached high standards and accuracy but is mainly conducted with stationary and expensive systems. The purpose of this study was to evaluate the accuracy of a low-budget portable system with special regard to the gracile and challenging nasal region. MATERIAL AND METHODS: 3D models of the perinasal area were acquired by impression-taking and the scanning of the generated plaster models (3Shape D500) or with a portable low-budget 3D stereophotogrammetry (FUEL3D® SCANIFY®) system. Four examiners analysed defined landmarks of the generated Standard Tessellation Language files with regard to accuracy and interobserver reliability by using 3dMDvultus™ software. A semi-automatic 3D best-fit analysis of both models was performed by using Geomagic® and the Root Mean Squared (RMS) errors were calculated. RESULTS: 41 volunteers were included, with 22 perinasal and perioral landmarks, 15 3D distances and eight 3D angles being analysed per data set. In a point-based analysis the mean spreads were partially smaller in the plaster model scans. Most measurements showed very high (>0.8) to excellent (>0.9) intraclass correlation coefficients, the lowest being found for columella length (0.686) and left nostril width (0.636). Overall, the mean RMS error between the superimposed surfaces was 0.89 ± 0.22 mm in the best-fit analysis. CONCLUSIONS: The corresponding software program was operator-friendly. The findings indicate that the analysed, affordable and portable system is a feasible solution for 3D image acquisition with comparable accuracy reported in the literature. Further studies will analyse the feasibility in neonates.

Validation of a low-cost laser scanner device for the assessment of three-dimensional facial anatomy in living subjects.

The present study compared the reliability of a low-cost laser scanner device to an already-validated stereophotogrammetric instrument. Fifty volunteers underwent duplicate facial scans through laser scanner and stereophotogrammetry. Intra- and inter-instrument reproducibility of linear distances, angles, facial surface area and volume was verified through the Bland-Altman test and calculation of absolute (TEM) and relative (rTEM) technical errors of measurement; rTEM was then classified as follows: <1% excellent; 1-3.9% very good; 4-6.9% good; 7-9.9% moderate; >10% poor. The scans performed through different devices were registered and superimposed to calculate the root mean square (RMS) (point-to-point) distance between the two surfaces. The same protocol was applied to a mannequin head. In inter-instruments comparison, 12/26 measurements showed a "good" rTEM; 5 were "very good". In intra-instrument comparison, most performances worsened, with only 10 of 26 measurements classified as "good" and "very good". All the measurements made on mannequin scans were at least "good", and 14/26 were "very good". Surface area was "very good" only in intra-instrument comparison; conversely, volumes were poorly repeatable for all the comparisons. On average, RMS point-to-point distances were 0.65 mm (inter-devices comparison), 0.56 mm (mannequin scans), 0.42 mm (intra-device comparison). In conclusion, the low-cost laser scan device can be reliably applied to inanimate objects, but does not meet the standards for three-dimensional facial acquisition on living persons.

Validation of three-dimensional wound measurements using a novel 3D-WAM camera.

To monitor wound healing, it is essential to obtain accurate and reliable wound measurements. Various methods have been used to measure wound size including three-dimensional (3D) measurement devices enabling wound assessment from a volume perspective. However, the currently available methods are inaccurate, costly, or complicated to use. As a consequence, we have developed a 3D-wound assessment monitor (WAM) camera, which is able to measure wound size in three-dimension and to assess wound characteristics. The aim of the study was to assess the intrarater and interrater reliability of the 3D wound measurements using the 3D camera and to compare these with traditional measurement methods. Four raters measured 48 wounds using the 3D camera, digital imaging method (2D area), and gel injection into the wound cavity (volume). The data were analyzed using linear mixed effect model. Intraclass and interclass correlation coefficient (ICC) and Bland-Altman plots were used to assess intrarater and interrater reliability for the 3D camera and agreement between the methods. The Bland-Altman plots for intrarater reliability showed minor differences between the measurements, especially the 3D area and perimeter measurements. Moreover, ICCs were very high for both the intrarater and interrater reliability for the 2D area, 3D area, and perimeter measurements (ICCs > 0.99), although slightly lower for the volume measurements (ICC = 0.946-0.950). Finally, a high agreement was found between the 3D camera and the traditional methods (2D area and volume) assessed by narrow 95% prediction intervals and high ICCs above 0.97. In conclusion, the 3D-WAM camera is an accurate and reliable method, which is useful for several types of wounds. However, the volume measurements were primarily useful in large, deep wounds. Moreover, the 3D images are based on digital technology and therefore carry the possibility for use in remote settings.

Effect of simulated intraoral variables on the accuracy of a photogrammetric imaging technique for complete-arch implant prostheses.

STATEMENT OF PROBLEM: Conventional impression techniques to obtain a definitive cast for a complete-arch implant-supported prosthesis are technique-sensitive and time-consuming. Direct optical recording with a camera could offer an alternative to conventional impression making. PURPOSE: The purpose of this in vitro study was to test a novel intraoral image capture protocol to obtain 3-dimensional (3D) implant spatial measurement data under simulated oral conditions of vertical opening and lip retraction. MATERIAL AND METHODS: A mannequin was assembled simulating the intraoral conditions of a patient having an edentulous mandible with 5 interforaminal implants. Simulated mouth openings with 2 interincisal openings (35 mm and 55 mm) and 3 lip retractions (55 mm, 75 mm, and 85 mm) were evaluated to record the implant positions. The 3D spatial orientations of implant replicas embedded in the reference model were measured using a coordinate measuring machine (CMM) (control). Five definitive casts were made with a splinted conventional impression technique of the reference model. The positions of the implant replicas for each of the 5 casts were measured with a Nobel Procera Scanner (conventional digital method). For the prototype, optical targets were secured to the implant replicas, and 3 sets of 12 images each were recorded for the photogrammetric process of 6 groups of retractions and openings using a digital camera and a standardized image capture protocol. Dimensional data were imported into photogrammetry software (photogrammetry method). The calculated and/or measured precision and accuracy of the implant positions in 3D space for the 6 groups were compared with 1-way ANOVA with an F-test (α=.05). RESULTS: The precision (standard error [SE] of measurement) for CMM was 3.9 µm (95% confidence interval [CI] 2.7 to 7.1 µm). For the conventional impression method, the SE of measurement was 17.2 µm (95% CI 10.3 to 49.4 µm). For photogrammetry, a grand mean was calculated for groups MinR-AvgO, MinR-MaxO, AvgR-AvgO, and MaxR-AvgO obtaining a value of 26.8 µm (95% CI 18.1 to 51.4 µm). The overall linear measurement error for accurately locating the top center points (TCP) followed a similar pattern as for precision. CMM (coordinate measurement machine) measurement represents the nonclinical gold standard, with an average error TCP distance of 4.6 µm (95% CI 3.5 to 6 µm). All photogrammetry groups presented an accuracy that ranged from 63 µm (SD 17.6) to 47 µm (SD 9.2). The grand mean of accuracy was calculated as 55.2 µm (95% CI 8.8 to 130.8 µm). CONCLUSIONS: The CMM group (control) demonstrated the highest levels of accuracy and precision. Most of the groups with the photogrammetric method were statistically similar to the conventional group except for groups AvgR-MaxO and MaxR-MaxO, which represented maximum opening with average retraction and maximum opening with maximum retraction.