Taťjana Dostálová

Evaluation of the Three-year Experience with All-ceramic Crowns with Polycrystalline Ceramic Cores

The objective of the study was to evaluate the clinical outcomes of all-ceramic crowns three years after placement of the restoration in the oral cavity. The aim of the present clinical study were surveyed the Procera®, Cercon® and LAVA™ systems. In total, 121 crowns were followed in 33 patients (7 men and 26 women) with an average age of 53.5 years. The eighty crowns were placed in anterior and forty one crowns in posterior teeth. The crowns were fabricated in two dental laboratories and delivered in two private dental practices. The clinical trial was conducted according to American Dental Association guidelines. The patients were requested to provide their consent to the regular clinical examination including radiographic and photographic records. A total of 102 crowns were made of zirconium oxide ceramic cores - 58 Cercon®; 43 LAVA™, while 19 crowns were made of aluminum oxide cores Procera®. The veneering ceramic LAVA™ Ceram was used. The success rate was analyzed using Kaplan-Meier statistics and, in our case, the overall three-year success rate reached 96.7%. All-ceramic crowns with polycrystalline ceramic cores have low susceptibility to fracture, in this study just 3.3%.

Modelling of the temporomandibular joints and the role of medical informatics in stomatology

This contribution deals with the 3D analysis of the temporomandibular joint. The main goal is to give the suitable formulation of mathematical model describing with sufficiently accuracy the TMJ and its function. The model is based on the theory of semi-coercive contact problems in linear elasticity, which leads to solving the variational inequality. The numerical solution is based on the finite element approximation of variational inequality corresponding to a generalized semi-coercive contact problem. The obtained numerical results will be discussed. Since the world is globalized new results from the bioinformatics and medical informatics play an important role. Therefore, the problem of an “international global mutual language” for surgeons in stomatology from different countries, and similarly in other branches in medicine, will be shortly discussed.

Temporomandibular joint and its two-dimensional and three-dimensional modelling

Detailed knowledge about the function and morphology of temporomandibular joint are necessary for clinical applications and for analyses of the function of temporomandibular joint prosthesis. Movements of temporomandibular joint are biomechanically sophisticated and are up-to-date not clear. Therefore, the aim of the paper is to give the suitable mathematical approach for analyses of temporomandibular joint. In the paper the analysis of the temporomandibular joint, loaded by traction and compression forces, is presented and shortly discussed. The obtained results, based on two- and three-dimensional mathematical models, represent an introductory work for further studies of biomechanical aspects of temporomandibular joint and of its artificial replacements. The models are based on the theory of contact problems in linear elasticity. For the numerical solutions of the investigated problems the FEM approaches are used and the used algorithm is based on an active-set method for quadratic programming.

Cephalometric Floating Norms for Czech Adults

The purpose of this study was to establish floating cephalometric norms for the description of the individual skeletal pattern in Czech adults. Floating norms provide a method of analysis that uses the variability of the associations among suitable cephalometric measures, on the basis of the regression model combining both sagittal and vertical skeletal parameters. Harmony box is a simple and useful tool for diagnostics of orthodontic anomalies according to individual cephalometric norms. 118 subjects, 53 male and 65 female, from Czech population were selected. The method of multiple regression analysis was used to determine interdependence among five cephalometric variables of the sample. Linear regression equations with corresponding r2 and standard error of the estimate (SE) were then illustrated as the harmony box. The results construct a harmony box based on correlated cephalometric variables. The multiple regression analysis of the data is graphically illustrated as a harmony schema which divides harmony box in three zones according to the type of the face - prognathic, orthognathic and retrognathic. The cephalometric floating norms describing the individual craniofacial pattern among Czech adults were established based on five correlated variables in the form of a harmony box.

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. Demirjians original 7-teeth method from 1973 and Demirjians revised 4-teeth method from 1976 appear to be the best methods for calculating the dental age of healthy Czech children of both genders.

Anomalous findings of number, morphology and size of permanent teeth in 7-10 years children living in the Czech Republic.

6,043 children, who were ordinary patients and children of Caucasian population, were examined clinically and radiographically. 430 children were aged 7-10 years. Dental anomalies were diagnosed in 14.1% (61 children) of those observed between 7-10 years. We aimed at numerical anomalies (78.6% of children with anomalies), morphological anomalies (19.6% of children with anomalies), size anomalies (3.2% of children with anomalies) and combinations of diagnoses (1.4% reflects the combinations of teeth 2 times calculated in combinations of diagnoses). Congenital numerical variations, i.e. hypodontia and hyperodontia, are among the most common deviations of the permanent dentition. Both conditions can occur as isolated traits or in association with other syndromes. Many studies indicate that hereditary factors are involved in the aetiology of anomalies. Gen MSX1 involves a primary position in mediating interactions between epithelium and mesenchyme in the development of teeth. Occurrence of dental anomalies is not very frequent; problems can arise with diagnosis of those affected teeth. It can be done using Orthopantomogram or Computed Tomography and 3D reconstruction. Some of the children with anomalies may have difficulties in treatment of affected teeth but in most cases the prognosis is good.