Maxillary Sinus Volume and Its Effect on Treated Impacted Canines.

The goal of study was to explore the role of 3D CBCT (cone beam computer tomography) in detecting impacted canines and their movement to evaluate the influence of orthodontic therapy parameters on treatment options, and to monitor quality of healing process based on shape and size of sinus maxillae volume. It is known that the volume of maxillary sinus plays an important role in patients with impacted teeth. The prospective study consisted of 26 individuals. For each individual, pre-treatment and post-treatment CBCT data were acquired. Changes of size, and position of impacted canine in 3D CBCT image before and after therapy were prepared using 3D reconstruction. Volumetric measurements of the maxillary sinuses were performed before and after orthodontic therapy of impacted canines, using InVivo6 software. The main effects MANOVA performed on linear measurements showed metric differences between pre-op and post-op images. A paired t-test showed no statistically significant differences between pre-op and post-op values of the sinus volume. Changes of size and position of impacted canine in 3D image before and after therapy were precise and reproducible, using 3D reconstruction in three planes - horizontal, midsagittal, and coronal. The linear measurements showed metric differences between pre-op and post-op images.

Photobiomodulation Therapy After Mesiodens Surgery: Evaluation of Immunological Markers and Three-Dimensional X-Ray Analysis-Placebo-Controlled Study.

Objective: Photobiomodulation therapy (PBMT) applies therapeutic lasers or light-emitting diodes radiation to the surface of the body. From the medical point of view, PBMT systems have been employed for reducing pain, inflammation, and edema, promoting healing of wounds, deeper tissues and nerves, preventing tissue damage, etc. Background data: PBMT or biostimulation has a wide range of applications in maxillofacial surgery. It is known that the therapy effect using three-dimensional (3D) image was not really clear during the healing process. Materials and methods: The treatment group comprised 38 patients, 18 of them were treated with laser radiation (diode laser 808 nm) and 20 patients presented the control group. The surgery plan was monitored using cone beam computed tomography, in particular the number, shape, and size of mesiodens were registered. The effectivity of laser therapy was assessed based on immunological tests-secretory immunoglobulin A (sIgA) and lysozyme levels measured in nonstimulated saliva before and after treatment. Results: For sIgA (both in millimeters and milligrams per liter), the measurements displayed differences between pre- and postsurgery values, the postsurgery values being significantly lower than the presurgery values. In addition, interaction with the laser treatment plan was found, meaning that the laser treatment affected the sIgA levels. The decrease in sIgA levels in the control group was statistically significant. However, there was no significant change in sIgA levels in the laser group. The lysozyme trends appeared to be identical to the sIgA levels, that is, rising in the laser group and decreasing in the control group. The initial values for each group, however, go in the opposite direction. Conclusions: The study has shown that the 3D techniques and technologies in combination with therapeutic laser systems could support not only a treatment plan, but they also directly influence the process of healing and reduce inflammation. The study was carried out under clinical project No. 00064203 (FN MOTOL).

Comparison of 2D OPG image versus orthopantomogram from 3D CBCT from the forensic point of view.

Forensic dental identification has employed traditionally 2D digital radiological imaging techniques. More recently, 3D cone beam computer tomography (CBCT) data, widely applied in clinical dentistry, have been gradually used. The purpose of this study was to compare the precision and quality of 2D digital orthopantomogram (OPG) and 2D OPG images generated from cone beam computed tomography (CBCT). The study sample consisted of 50 patients with archived conventional 2D OPG and 3D CBCT images. Patients signed an informed consent form to take part in our study. Measurements of the mandible, teeth and dental restorations were taken by two observers on calibrated 2D OPG and 3D CBCT-to-OPG images using measurement functionalities of DOPLHIN software. Acquired dimensions were compared side by side and images of fillings were superimposed. For better visual comparison and more efficient image registration, the methods of spline interpolation were used. The pairs of absolute measurements obtained from conventional OPG and CBCT-to-OPG-converted images were highly correlated (p < 0.05). However, larger, and horizontally measured distances were revealed to be more affected than shorter vertically taken measurements. In relative terms, CBCT-generated width/length indices of the canines and the first molars ranged from 84% to 99.8% of those acquired from traditional OPGs. In addition, corresponding points on the teeth and fillings were compared side by side and in superimposition. The average coincidence of images was 6.1%. The results revealed that for selected metric variables 2D OPGs and 3D CBCT-generated OPGs were complementary and could be used for forensic comparisons.

Comparison of dental and chronological age based on CBCT-generated panoramic images and reconstructed 3D images.

Objective: The aim of the present study was the comparison of the known chronological age of the studied subjects by dental age evaluated according to the developmental stages of seven permanent teeth in the lower left dental quadrant and to determine how much the child's dental age differs from its chronological age. Methods: Radiographs of 579 patients (288 boys and 291 girls), aged 3-16 years, from the database of the Radiological Clinic of the Second Medical Faculty of Charles University and the Motol University Hospital in Prague were reviewed. The patients were examined for different indications by cone beam computed tomography (CBCT). The evaluation of the developmental stages of the teeth was performed from generated panoramic images and reconstructed three-dimensional (3D) images. The developmental stages of the teeth were evaluated by Demirjian's method for dental maturity based on seven teeth of the lower left dental quadrant (Demirjian et al. 1973). The evaluated variables were mineralization and development of the dental crown, length of the root, and closure of the apical foramen. Results: The difference between chronological and dental age was -0.16 (standard deviation (SD) 1.68, p-value 0.7) in boys and -0.10 (SD 1.65, p-value 0.27) in girls, on average. These results confirm that the method is accurate. Low SD values express the precision of the evaluation. Conclusion: Use of reconstructed 3D images makes the evaluation of the maturation of teeth more accurate in comparison to the use of generated panoramic images. The development of teeth (with exception of third molars) was complete at the age of 16 in 97.3% of the studied subjects.

3D Multislice and Cone-beam Computed Tomography Systems for Dental Identification.

3D Multislice and Cone-beam computed tomography (CBCT) in forensic odontology has been shown to be useful not only in terms of one or a few of dead bodies but also in multiple fatality incidents. 3D Multislice and Cone-beam computed tomography and digital radiography were demonstrated in a forensic examination form. 3D images of the skull and teeth were analysed and validated for long ante mortem/post mortem intervals. The image acquisition was instantaneous; the images were able to be optically enlarged, measured, superimposed and compared prima vista or using special software and exported as a file. Digital radiology and computer tomography has been shown to be important both in common criminalistics practices and in multiple fatality incidents. Our study demonstrated that CBCT imaging offers less image artifacts, low image reconstruction times, mobility of the unit and considerably lower equipment cost.

Using Dental Age to Estimate Chronological Age in Czech Children Aged 3-18 Years.

The Demirjian methods to determine dental age are based on analysis of orthopantograms. The dental age estimation is based on establishing the tooth development stages. The purpose of this study was to assess the accuracy of estimation of dental age by Demirjian in the use of all of his four methods. 505 Czech healthy boys and girls aged 3 to 18 years were examined radiographically at the Department of Stomatology, Second Faculty of Medicine, Charles University in Prague. It was mentioned the factors of underlying diseases influence the accuracy of the dental age estimation. For statistical evaluation, descriptive statistics was used to compare deviations of the mean values of chronological and dental age in each age group. The resulting difference between dental age and chronological age is not significant in both genders only when using both Demirjian 7-teeth methods of 1973 and 1976. Therefore these may be most appropriately used for forensic age estimation. There are shown standard deviation differences in different countries. Demirjian's original 7-teeth method from 1973 and Demirjian's revised 4-teeth method from 1976 appear to be the best methods for calculating the dental age of healthy Czech children of both genders.

Possibility of reconstruction of dental plaster cast from 3D digital study models.

OBJECTIVES: To compare traditional plaster casts, digital models and 3D printed copies of dental plaster casts based on various criteria. To determine whether 3D printed copies obtained using open source system RepRap can replace traditional plaster casts in dental practice. To compare and contrast the qualities of two possible 3D printing options--source system RepRap and commercially available 3D printing. DESIGN AND SETTINGS: A method comparison study on 10 dental plaster casts from the Orthodontic department, Department of Stomatology, 2nd medical Faulty, Charles University Prague, Czech Republic. MATERIAL AND METHODS: Each of 10 plaster casts were scanned by inEos Blue scanner and the printed on 3D printer RepRap [10 models] and ProJet HD3000 3D printer [1 model]. Linear measurements between selected points on the dental arches of upper and lower jaws on plaster casts and its 3D copy were recorded and statistically analyzed. RESULTS: 3D printed copies have many advantages over traditional plaster casts. The precision and accuracy of the RepRap 3D printed copies of plaster casts were confirmed based on the statistical analysis. Although the commercially available 3D printing enables to print more details than the RepRap system, it is expensive and for the purpose of clinical use can be replaced by the cheaper prints obtained from RepRap printed copies. CONCLUSIONS: Scanning of the traditional plaster casts to obtain a digital model offers a pragmatic approach. The scans can subsequently be used as a template to print the plaster casts as required. Using 3D printers can replace traditional plaster casts primarily due to their accuracy and price.

The application of CamScan 2 in forensic dentistry.

Forensic dentistry plays a major role in body identification. The dental examination is very accurate and also, nowadays, in the time of a comprehensive fingerprint and DNA assessment, objectively supported. The identification, which is based on the dental documentation, leads up to 43-89% of a successful process. The purpose of the study is to describe the techniques employed by forensic odontology to identify human remains and also to provide details of some of the novel developments within this area. Comparative methods of dental identification of the unknown subject with pre-mortem clinical records, X-ray images, implant presence, superimposition and DNA analysis confirm the identity of the individual. It was shown that dental identification of a person is based on unique individual characteristics of the dentition and dental restorations, relative resistance of the mineralised dental tissues and dental restorations to changes resulting from decomposition and harsh environmental extremes such as conditions of temperature and violent physical forces.

Superimposition and projective transformation of 3D object.

Superimposition is an efficient method for evaluation of coincidence between a skull and a photo portrait. The principle of superimposition method lies in the projection of the skull into the face image. During the projection of an object with a perspective camera, the mapping of a three-dimensional object into a two-dimensional image takes place. The acquired images of the same object are more or less distorted due to various photographic conditions, due to extrinsic and intrinsic parameters of the camera. The distortions have important influence onto reliability of human identification by the superimposition method. Mathematically we can describe most of the distortions. On the basis of the description the divergences could be simulated and in some cases eliminated by geometric transformation of the compared images. We are presenting a mathematical model of the standard projective camera and the mathematical description of distortions which are important for the superimposition process. The results show the distortions and the elimination of the distortions by means of the projection model.