Tatjana Dostalova

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

ObjectivesTo 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 – open source system RepRap and commercially available 3D printing.Design and settingsA 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 methodsEach 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.Results3D 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.ConclusionsScanning 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.

Endodontic Treatment with Application of Er:YAG Laser Waveguide Radiation Disinfection

OBJECTIVE The objective of this study is to examine the ability of Er:YAG laser radiation. Using a movable waveguide helps to obtain an antibacterial effect, not only in root canal walls but also in the surrounding tissues. BACKGROUND DATA Conventional endodontic treatment is not fully effective due to microbial colonization of root canal walls dentin in premolars and molars. Various laser systems seem to be effective to kill the remaining microbial content in the root canal. The problem is in the flexibility of laser system tips. MATERIALS AND METHODS The Er:YAG laser system was designed with a fluorocarbon polymer-coated silver hollow glass waveguide. Root canal systems of 44 premolars and molars were treated endodontically, using a step-back technique; 10 teeth were then treated with calcium hydroxide paste, and 22 teeth were irradiated by a movable waveguide. Before and after treatment, the colony-forming units were counted to determine 21 various microorganisms. RESULTS Classical enlargement and shaping of the root canal is effective in 60%. Application of calcium hydroxide prepares sterile root canal in 80%. Er:YAG laser irradiation via movable waveguide (energy of 100 mJ, 30 pulses, repetition rate 4 Hz) can ensure residual disinfection of the root canal. CONCLUSION Application of Er:YAG laser radiation through a flexible waveguide helps to attain antibacterial effect, not only in the root canal walls, but also in the surrounding tissues. Therapeutic doses of laser radiation guarantee one-step disinfection, including of anaerobic microorganisms.

Ceramic Bracket Debonding by Tm:YAP Laser Irradiation

OBJECTIVE The aim of this study was to prepare a simple and reliable method for ceramic bracket debonding, ensuring minimal changes in the enamel structure and an acceptable temperature rise in the pulp. BACKGROUND DATA Ceramic bracket debonding is based on the principle of degrading the strength of adhesive resin between the tooth and ceramic bracket. The search for a safe and efficient method of adhesive resin removal following debonding has resulted in the introduction of a wide range of instruments and procedures, among which proper use of laser irradiation can be promising. METHODS The debonding of two types of ceramic brackets utilized a diode-pumped Thulium:Ytterbium-Aluminium-Perovskite (Tm:YAP) microchip laser generating irradiation at a wavelength of 1998 nm (spot size 3 mm; focused by lens), with two power settings (1-2 W). Loss of enamel and residual resin on teeth, as well as rise in temperature inside the tooth were subsequently investigated in detail. RESULTS A 1W power of irradiation during a 60-sec period resulted in a temperature rise from 3 to 4°C in the approximate root location. This power is also suitable for debracketing from the point of view of damage to enamel lying below the bracket. Only a slight damage to the enamel was registered by SEM compared to conventional bracket removal. CONCLUSIONS Use of a Tm:YAP laser (wavelength 1998 nm, power 1 W, irradiance 14 W/cm(2), interacting time 60 sec) which is at the same time compact and small enough to be used in the dental practice, together with moderate cooling, could be an efficient tool for debracketing.

Electronic Health Record for Forensic Dentistry

OBJECTIVES To identify support of structured data entry for electronic health record application in forensic dentistry. METHODS The methods of structuring information in dentistry are described and validation of structured data entry in electronic health records for forensic dentistry is performed on several real cases with the interactive DentCross component. The connection of this component to MUDR and MUDRLite electronic health records is described. RESULTS The use of the electronic health record MUDRLite and the interactive DentCross component to collect dental information required by standardized Disaster Victim Identification Form by Interpol for possible victim identification is shown. CONCLUSIONS The analysis of structured data entry for dentistry using the DentCross component connected to an electronic health record showed the practical ability of the DentCross component to deliver a real service to dental care and the ability to support the identification of a person in forensic dentistry.

Average arch widths and associated changes between initial, post-treatment and post-retention measurements

Computer image monitoring was used for evaluation of dental arch changes. A new special device captured geometrically calibrated images permitting comparison of several different dental casts. In the first part of this study 792 sets of study casts were screened. Measurements of dental arch width between reference points of canines, first premolars and first molars were made: upper jaw: men: canines: 35.1 +/- 0.13 mm; first premolars: 37.5 +/- 0.13 mm; first molars: 48.1 +/- 0.19 mm; women: canines: 33.4 +/- 0.13 mm; first premolars: 35.6 +/- 0.15 mm; first molars: 46.7 +/- 0.19 mm. In the second part of the study, changes between initial, post-treatment and post-retention alignment (5-years after orthodontic therapy) of upper and lower dental arch of 36 subjects were analyzed. Upper and lower arch compression in first premolars and molars area was visible before treatment. We conclude that computer image monitoring can be used for evaluation of dental arch changes during the different steps of treatment.

Voice-supported Electronic Health Record for Temporomandibular Joint Disorders

OBJECTIVES To identify support of structured data entry for an electronic health record application in temporomandibular joint disorders. METHODS The methods of structuring information in dentistry are described and the interactive DentCross component is introduced. A system of structured voice-supported data entry in electronic health record on several real cases in the field of dentistry is performed. The connection of this component to the MUDRLite electronic health record is described. RESULTS The use of DentVoice, an application which consists of the electronic health record MUDRLite and the voice-controlled interactive component DentCross, to collect dental information required by temporomandibular joint disorders is shown. CONCLUSIONS The DentVoice application with the DentCross component showed the practical ability of the temporomandibular joint disorder treatment support.

Comparison of preparation speed of Er:YAG laser and conventional drilling machine

Clinical tests of the caries treatment with a Er:YAG laser system have been very promising. The problem of the Er:YAG laser drilling machine is the speed of preparation. It is not possible to increase the laser energy and repetition rate because this process is directly connected with temperature elevation. Therefore attention has been paid to define the differences between the classical and the laser drilling effect with a safe but effective laser energy and repetition rate. For the experiment, an Er:YAG laser drilling machine with an articulated arm was designed. Thirty samples of extracted human teeth were cut by both this system and classical drilling machine. The circumference, area and structure of surface sections were observed and analyzed. From the comparison of the measured time of preparation significant differences followed from the time of preparation. The time of preparation related to 1 mm2 of the cut surface was 5.42 sec for the Er:YAG laser machine and 0.66 sec for the classical method. From this comparison it follows that the laser system is 8 times slower than the classical preparation technique. In both cases the roughness of the surface analyzed by SCAN was found similar. Also, there were no differences between the distribution of the elements, especially calcium and phosphorus.

Optical properties and surface structure comparison of tooth whitening using four laser systems and chemical action agents

The purpose of the study is to evaluate the effect of various laser techniques for bleaching teeth in office vital whitening. Hydrogen peroxide (30% concentration) and carbamide peroxide (10% solution) were used for chemical activation of bleaching process. Extracted non-carcious upper central incisors were exposed to laser radiation. Four different laser systems (Nd:YAG laser SHG, wavelength 0.53 μm, CTE:YAG laser, wavelength 2.7 μm, Nd:YAG laser, wavelength 1.06 μm, and alexandrite laser, wavelength 0.75 μm) were applied to accelerate the speed of the process. The end of chemical exposition was verified by the change of bleaching agent color. The color change was determined by stereomicroscope (Nikon SMZ 2T, Japan), the quality of surface structure was checked by scanning electron microscope Joel (Japan). The speed of bleaching rnaged from 630 s (chemical methods only) to 250-340 s (chemicals + alexandrite laser radiation). The Alexandrite laser application was considered an elective process to decrease the time of bleaching without modifying the surface.

Lasers in Dentistry: Overview and Perspectives

Dental treatment by laser radiation is nowadays a well-known and widely used technique in dentistry. The laser can be thought of as an alternative instrument that sometimes completes or substitutes for traditional dental techniques. Current applications of laser radiation in dentistry depend on the penetration depth of the radiation into the tissue (given by the radiation wavelength) and then on the duration of this interaction (continuous versus pulsed laser regime), on the energy, length of pulse, and radiation power. It is possible to summarize that for the purposes of current clinical dentistry, a span from the visible to the far infrared portions of the electromagnetic spectrum (*400 nm 10.6 lm) can be used. The dental application can be divided on the following.

Dental implants and improvement of oral health-related quality of life

OBJECTIVES Oral health-related quality of life (OHRQoL) is a multifaceted field involving many factors. The aim of our study was to assess whether implant therapy improves OHRQoL in dental patients. METHODS Patients receiving at least one implant completed a health-related questionnaire before and after the implantation (minimum 1.5 months). Questions covered the functional and aesthetic scales (AS). Paired differences in individual scores were analysed using the Wilcoxon signed-rank test. A univariate analysis of covariance was used to relate overall and scale-specific average paired differences to age, gender, marital and educational status. Multivariate analysis of covariance was used to assess interactions between the covariates and different scales of outcome. All tests were performed at statistical significance level α = 0.05. RESULTS All twelve Wilcoxon tests supported an improvement in OHRQoL after implant placement. On the AS, the mean difference in OHRQoL scores was found to be associated with marital status, presence of aesthetic reasons for undergoing the surgery and number of front teeth replaced by implants. On the functional scale (FS), most significant associations were observed with the number of front teeth replaced via implantation, followed by the presence of chewing problems and marital status. The multivariate analysis helped to identify the covariates that varied significantly over the two scales of interest. CONCLUSIONS Effects of covariates responding significantly differently on different scales should not be summarized using an overall univariate analysis, using paired score differences averaged over all items. Such effect summary would be misleading. In the present study, significant implant-related improvements in OHRQoL were observed on both the aesthetic and FS in patients with at least one implant in the front dental area.