Measurement of the Electromagnetic Field in Dentistry

The aim of this study was to measure the magnetic field in dentistry together with simultaneous substraction of direct ground component of the magnetic field. The research instrument used to measure the power of the magnetic field was of our own design. It measures the magnetic field by the Hall sensor that is powered with 5 to 10 V and is integrated in one chip together with preamplifier. The sensor output is differential (Q1-Q2) and proportionate to measurement values of magnetic induction. As the values of alternate fields in a laboratory setting are small the differential output voltage should be increased by about 100 times. Our study samples consisted of instruments currently available in dentistry: halogen lamps, polymerizing lamps, amalgam mixers, micromotors and dental chairs. On the basis of our study results and statistical analysis the following conclusions are made magnetic field spreads through space in ISOTROPIC manner. The greatest frequency obtained at the smallest distance was 100 kHz. The sensitivity of the measurement instrument was 0.0001 μT and the majority of instruments produce magnetic radiation higher than 4o G. The power of the magnetic field decreases with increasing distance from the source. The investigated instruments produce a relatively mild magnetic field. The instruments with stronger magnetic fields are located far enough from the persons on whom they act. The newly produced instrument acts on their environment by smaller magnetic fields

Hereditary and Environmental Dental Findings in Identification of Human Remains

The paper presents the results on hereditary and environmental dental findings in identification of human remains exhumed from mass graves in the Republic of Croatia. The total of 17.880 teeth from all the categories (incisors, canines, premolars and molars) was examined. Hereditary findings of the teeth such as shape, size, position, as well as age were used in all of the cases confirming and completing the identification. In only 15% of the cases they were the starting points for the identification that would be later confirmed with another 3 – 5 traditional identification procedures. Disturbances in tooth eruption were recorded in 22% of the cases, impaction of teeth in 10%, and retarded eruption of teeth in 12%. Disturbances of tooth position were recorded in 65% of the cases. Tooth rotation in 26% and diastema mediana in maxilla or mandible in 39%. Disorders of tooth number in the form of unilateral and bilateral missing of lateral maxillary incisors were recorded only in 2% of the monitored cases. Abnormalities of the tooth shape were found in 11% of the cases. The majority of them were found on the tooth crowns 6%, and less on the tooth roots 5%. Environmental dental findings that were the most significant for the identifications were prosthetic appliances in 30% of cases. Prostheses were helpful in the identification of 3% of the cases, while crowns and bridges were helpful in 27% of the cases. Ante mortem teeth extractions were helpful in 25% of the cases. Teeth restorations were recorded in 20 % of the identified cases, amalgams in 19% and aesthetic filings in 1%. Dental caries was helpful in only 10% of the cases, superficial caries in 3% and caries of dentin in 7% of cases

Hereditary and Environmental Dental Findings in Identification of Human Remains

The paper presents the results on hereditary and environmental dental findings in identification of human remains exhumed from mass graves in the Republic of Croatia. The total of 17.880 teeth from all the categories (incisors, canines, premolars and molars) was examined. Hereditary findings of the teeth such as shape, size, position, as well as age were used in all of the cases confirming and completing the identification. In only 15% of the cases they were the starting points for the identification that would be later confirmed with another 3 – 5 traditional identification procedures. Disturbances in tooth eruption were recorded in 22% of the cases, impaction of teeth in 10%, and retarded eruption of teeth in 12%. Disturbances of tooth position were recorded in 65% of the cases. Tooth rotation in 26% and diastema mediana in maxilla or mandible in 39%. Disorders of tooth number in the form of unilateral and bilateral missing of lateral maxillary incisors were recorded only in 2% of the monitored cases. Abnormalities of the tooth shape were found in 11% of the cases. The majority of them were found on the tooth crowns 6%, and less on the tooth roots 5%. Environmental dental findings that were the most significant for the identifications were prosthetic appliances in 30% of cases. Prostheses were helpful in the identification of 3% of the cases, while crowns and bridges were helpful in 27% of the cases. Ante mortem teeth extractions were helpful in 25% of the cases. Teeth restorations were recorded in 20 % of the identified cases, amalgams in 19% and aesthetic filings in 1%. Dental caries was helpful in only 10% of the cases, superficial caries in 3% and caries of dentin in 7% of cases

Dynamic Effects of Food Consistency on Chewing Motions

The purpose of the study was to find evidence of how different types of food consistency affect chewing motions, especially the forward, downward and sidewise extents of motion of the lower jaw. Nineteen individuals with intact tooth sequence, aged from 20 to 37 years, were asked to chew three types of food of different consistency (banana, bread, carrot). The motions of the lower jaw were recorded by ELITE system, i.e. the measurement instrument that by stereo-photo-grametric procedures calculates space co-ordinates of markers on faces of the study subjects. The system enables continuous recording of lower jaw motions in three dimensions, without any possibility of the study subjects’ influencing the operation of the instrument, which significantly decreases the possibility of error. Study results have shown that in all 19 subjects a greater food consistency increases the extent of chewing motion. In each individual study subject different average values were found for equal shifts of lower jaw when chewing the same type of food. Although varying from subject to subject, the chewing cycle depends to a great extent on food consistency. By increasing the consistency of a bite, the extent of lower jaw motion has increased in every single study subject

Foramen Mandibulae as an Indicator of Successful Conduction Anesthesia

Comparative measurements were made of 144 orthopantomographs in 50 patients with successful and 94 patients with unsuccessful inferior alveolar nerve block anesthesia. The results show that the bony lingula is prominent in 28.5% of all patients, or in 56.0% of those with unsuccessful anesthesia. The variables mandibular notch vs. mandibular foramen (MN-MF) and the anterior ramus ridge vs. mandibular foramen (ARR-MF) show greater distances in the group of patients with successful anesthesia, while the variables of posterior ramus ridge vs. mandibular foramen (PRR-MF) and mandibular angle vs. mandibular foramen (MA-MF) were greater in the group of patients with unsuccessful anesthesia (p > 0.05). It is concluded that the variability in position of the mandibular foramen among others may be responsible for an occasional failure of inferior alveolar nerve block

Vitrification versus controlled-rate freezing in cryopreservation of human ovarian tissue

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Tooth Morphology in Function of Selfprotective Mechanism

The degree of curvature of vestibular and oral tooth surfaces is determined by the shape sequence from the tooth crown to the epithelial attachment and the alveolar bone, and directly influences the health of gingiva and the entire tooth support system. The goal of this research was to determine vestibulo-oral planes of upper and lower permanent premolars and molars and the thickness of the associated alveolar osseous wall, and 2,727 measurings were processed using pertinent statistical procedures. The results have shown the degree of curvature of vestibular and oral tooth surfaces to be higher in upper teeth than in lower ones (p>0.05); vestibular convexities higher than oral ones and especially noticeable at the junction from the meandle to the lower third of the crown. Higher vestibular curvature also entailed thicker osseous wall. All results were higher than the ones found in literature. We consider our results to be relevant for our population. The research on the relationship of teeth and the alveolar bone should be continued by using even more test points and more sophisticated research procedures

Model for Computer Simulation of Bone Tissue

The paper deals with the dependence of the torsional moment on the angle of the compact bone torsion in laboratory animals and humans. Based on the data for laboratory animals obtained by measurements, the data on dependence of the torsional moment and the angle of torsion were predicted for humans. The measurements were carried out in four groups of laboratory animals. One was the control group, and the other three groups were treated by various vitamin D3 metabolites. The same measurements were performed also in only one group of humans, due to the impossibility to treat humans with vitamin D3 metabolites. The functional relationship between the angle of torsion and the torsional moment for all the groups of animal bone tissue were determined by measurements, and results were used to predict the reaction of the human compact bone tissue if treated by vitamin D3 metabolites

Influence of Diet on Dental Caries in Diabetics

Two groups of population consisting of 84 patients suffering from diabetes (60 type I, 24 type II) and 69 nondiabetics of the same age have been examined on: oral hygiene index (OHI), frequency of daily tooth brushing, dietary habits and incidence of dental caries by registration of the decayed, missed and filled dental surfaces (DMFS-index). OHI in type I and type II diabetes was found to bee slightly worse than in nondiabetics, but not significantly (p > 0.05). In the number of daily tooth brushing there is not significant difference between diabetics and nondiabetics. All diabetics have considerably lower daily intake of total as well as simple carbohydrates than nondiabetics. The diabetics have a significantly higher daily intake of dietary fibers, calcium and phosphorus as well as the number of meals with simple carbohydrates and also DMFS-index than the nondiabetics. A significantly higher incidence (p < 0.01) of caries location was found on the buccal and labial cervical areas among patients suffering from diabetes. Explanation for this could be more frequent daily intake of lowmolecular carbohydrates with an improper calcium phosphorus ratio

Measurement of Magnetic Field in Dentistry

The principal objective was to measure the magnetic fields occurring in dental surgeries at simultaneous subtraction of direct ground component of the magnetic field. A specifically designed instrument with the Hall probe was used for the measurement. It consisted of two amplifiers and a low frequency filter. Its task was to measure mean square values of the field (RMS) dependent on the position in space. Qualitative and quantitative analyses of the investigated variables enabled making conclusions about the magnetic fields in dental surgeries. A number of studies have shown that many dental instruments produce radiation with magnetic field higher than 40 G, at a significant decrease in power of the magnetic field with increasing distance from the source. It has also been reported that instruments of older generations produce stronger magnetic fields than do the new ones