A computerized method for mathematical description of three-dimensional root canal axis.

Knowledge of the three-dimensional (3D) morphology of root canals is important for successful endodontic treatment. The objective of the present study was to determine the 3D root canal axis mathematically. Two views (mesiodistal and buccolingual) of digitized images were taken from extracted natural human teeth. Geometric reconstruction to standardize projection geometry was conducted on images. Because 90-degree turn-around image pairs are Monge images of a given root canal, these Monge images were positioned using photogrammetric methods. Each well-ordered axis pair of a given root canal was put into a common coordinate system resulting in 3D polynomial function of the actual root canal. On the basis of the results gained using 10 samples evaluated with the Friedman statistical test, this description seems to be reproducible. The 3D representation of the root canal may help the clinicians in choosing the optimal instruments and shaping techniques. The root canal axis that is described by the 3D function forms a basis for determination of curvature values and torsion values in each of the axis points. Evaluating these values may also yield a new type of classification.

An atomic force microscopy study on the effect of bleaching agents on enamel surface.

OBJECTIVES: The aim of the present study was to evaluate the effect of three peroxide-containing bleaching agents, Opalescence, Nite White and a 30% hydrogen peroxide solution, on enamel surfaces using Atomic Force Microscopy (AFM). METHODS: Fifteen non-carious human incisors (ten maxillary and five mandibular, extracted for periodontal reasons) were used. The teeth were divided randomly into three groups of five, according to the bleaching agents. The labial surface of each tooth was imaged by AFM before and after treatment. Each bleaching agent was applied for a total of 28 h (in individual 4 h treatments). The specimens were examined only after 28 h of treatment. RESULTS: On comparing the AFM images of untreated and treated enamel, surface alterations were observed after 28 h of treatment with Opalescence, Nite White and 30% hydrogen peroxide solution. Several grooves present in the enamel surface of untreated teeth became deeper after the bleaching procedure. The depths of the grooves increased in each case. The increase in the depth of grooves was more pronounced in the case of the 30% H2O2 solution. CONCLUSION: Home-use bleaching agents are capable of causing enamel surface alterations. It is hypothesized that the peroxide-containing bleaching agents affect the organic phase of enamel. Peroxides can affect not only the surface but also the inner structure of enamel. As a result of its low molecular weight, hydrogen peroxide can penetrate into the enamel. Thus, inner oxidative effects are more likely to occur in the subsurface enamel where more organic material is present and oxidation is capable of altering the outer enamel and the surface.

Oral manifestations of patients with Turner syndrome.

OBJECTIVE: The purpose of this study was to conduct a complete analysis of orofacial abnormalities of patients with Turner syndrome. STUDY DESIGN: Twenty nine patients with Turner syndrome and 30 without Turner syndrome (control group) were studied. The subjects were screened for cariological and periodontal alterations, orthodontic anomalies, tooth crown morphologic condition, alveolar arch dimensions, and temporomandibular joint function. RESULTS: Significantly lower mean values for decayed, missing, and filled teeth were found for patients with Turner syndrome as compared with the control group. Plaque and gingival indices were significantly higher in the study group. Orthodontic anomalies were more frequent and severe in patients with Turner syndrome. Our investigation showed reduced tooth crown size in the study group. The alveolar arch of the maxilla was narrower and of normal length, but the mandibular arch was shorter and broader. There was no significant alteration in temporomandibular joint function in the 2 examined groups. CONCLUSIONS: Our examination showed the importance of early diagnosis of oral anomalies and timely treatment of dental problems for patients with Turner syndrome.

3D reconstruction based on hard tissue microtome cross-section pictures in dentistry.

The aim of this study was to examine the accuracy of the computerized 3D surface analyzing and volume measuring method in dentistry. Two different types of test objects were used in the first part of the measurements. Each sample of the two groups was cross-sectioned using a hard tissue microtome. The sections were photographed on both sides and were projected on a graphical tablet and analyzed using a computer program. The measured and calculated parameters were compared. In the second part, 200 microm thick horizontal sections were prepared from 11 human incisor roots using the hard tissue microtome. This way, five sections were prepared from the apical 2 mm of each root. The effects of section thickness and number were modeled by decreasing the inclusion rate of the obtained number of sections from 10 to 2 and its influence on the calculated results was determined. This method was suitable for the approximation and analysis of 3D parameters. The results indicated that using 200-300 microm section thickness, the measured values were approximately 8-21% lower than the real parameters.

[Genetic counseling and prenatal care after medications during the first trimester]. / Genetikai tanácsadás és gondozás elsó trimeszterbeli gyógyszerszedés miatt.

Analysis of the outcome of 127 pregnancies with first trimester medication (8.4% of the total number of the patients seeking genetic advice in 1997 at the Institute of Medical Genetics in Szeged) was carried out. The gestational age at the time of the medication and genetic counselling, the indications of the treatment, the drugs, the estimated fetal risk, and results of genetic ultrasound examinations and pregnancy outcome were evaluated. The majority of pregnant woman (78%) asked for genetic counselling before the 12. gestational week. The main indications the treatment were: infections, psychiatric-neurologic (depression, anxiety, epilepsy), endocrine (diabetes, hyperthyreoidism), and cardiovascular diseases and gastrointestinal problems. The main groups of the drugs were: antibiotics, antipyretic-, antidepressive-, antidiabetic- and antihypertensive drugs. When the multiple medication was conducted by simultaneous administration of two or more drugs, a complex risk calculation was performed. The fetal risk was higher than 10% in 31 cases (24%). The ultrasound examinations performed by qualified sonographer contributed to a correct evaluation and to reliable follow-up of pregnancies. No suspicious ultrasound finding was reported in the first trimester. However, a severe fatal brain malformation was found in a second trimester pregnancy, which was terminated by the couple's request in the 18th gestational week. A complete follow-up was obtained in 70.9% (90) of the cases. Out of 64 pregnancies intended to continue to term 4 fetal malformations were found. Of them three malformations (patent ductus arteriosus, Robin sequence and a ventricular septal defect) were explored at birth or in the newborn period. The actual 6.3% of fetal malformations was higher compared to the rate expected at birth, but almost equal to the rate of congenital malformation found up to the end of the first year of age in Hungary.

[Chemical plaque control]. / Kémiai plakk-kontroll.

Most of the diseases with which dentists must deal with are related to microbial plaque and bacterial infection. The mechanical removal of supra- and subgingival plaque by the patient and by the dentist respectively, is time consuming and exacting, furthermore it is not one hundred per cent successful. There has been extensive search for many years for chemical agents that could supplement or even substitute mechanical plaque removal. Many chemical agents delivered in different ways were tested. Chemotherapeutics of various modes of action have to meet pharmacokinetic and biological requirements. Apparently the ideal anti-plaque agent is not yet available, so that they should be reserved for well defined clinical situations and short--or medium--term application.

[Contributions to the history of Hungarian periodontology]. / Adalékok a magyar parodontológia történetéhez.

The author reviews the highlights of the work and thoughts of those Hungarian dentists, such as Arkövy, J., Robicsek, S., Károlyi, M., Orbán, B. and Morelli, G. who contributed the most to the development of the practice and science of periodontology.

[Testing the reliability of face bow registration]. / Az arcíves regisztrálás megbízhatóságának vizsgálata.

The reliability of the Quick ear face-bow to transfer an arbitrary hinge axis to a Quick articulator was clinically compared with a Dentatus face-bow. 40 measurements were carried out on 8 patients with both instruments and were compared. The statistical analysis of the data indicated no difference between these facebow recordings. Furthermore both showed good reproducibility. This suggests that the same clinical results can be reached by these instruments.

[Probing and occlusal caries]. / Szondázás és occlusalis caries.

Occlusal fissures are one of the most frequent locations for dental caries. In order to detect early caries lesions in terms of "sticky fissures" tactile examinations with a sharp explorer are important parts of a classical clinical examination. The aim of the present investigation was to study whether probing with an explorer contributed to the development of occlusal caries in permanent of first molars. The study was carried out in 101 children (56 girls and 45 boys) who had intact pairs of first molars. Altogether 104 first molar pairs were studied. One and two years later both of the pairs were probed, but there was no significant correlation found between previous probing and occlusal caries.

[The effect of toothbrushing on approximal dental surfaces]. / A fogmosás hatásossága az approximalis fogfelszíneken.

Altogether 52 teeth (20 anteriors, 13 premolars and 19 molars) scheduled for extraction were used for study. Before extraction the teeth were brushed with a medium textured toothbrush applying the modified Bass method with five strokes of proximal cleaning. The lack of professional and proximal cleaning aids makes planimetrically. The following conclusions were drawn: 1. The usual five strokes with a toothbrush are not able to remove old plaque, therefore professional tooth cleaning is necessary. 2. After toothbrushing twice as much plaque remains on the proximal than on the buccal and lingual surfaces. This implies the necessity of proximal cleaning. The lack of professional and proximal cleaning aids makes the establishment of good oral hygiene illusorical.

[Involvement of the temporomandibular joint in rheumatoid arthritis]. / A temporomandibuláris ízület érintettsége rheumatoid arthritis esetén.

The rheumatoid arthritis is a systemic connective tissue disease, that most of the cases involve the temporomandibular joint. The diagnosis of local involvement is usually not difficult because the disease often starts in other peripheral small joints. The radiographic signs can be observed more frequently than clinical and subjective symptoms. The local symptoms are pain, opening difficulty, stiffness in the morning and swelling. The maximal mouth opening is restricted by the reduced translatory movement of the mandibular condyle. The aim of this case presentation is to describe the temporomandibular aspects of the rheumatoid arthritis and to suggest the usefulness of the condylar movement registration in the diagnostic procedure of the disease.

[The size of the overlapping of the gingival margin in Class II amalgam fillings examined in the teeth and their radiographic images]. / A II. osztályú amalgámtömések gingivális szélei túlérésének nagysága a fogakon és azok röntgenképein.

200 Class II extracted teeth provided with amalgam filling were examined. The size of the overlapping of the fillings were measured on the X-ray pictures and in the transverse section of the teeth embedded in self-cementing plastic under a stereomicroscopy by means of an ocular micrometer. The mean overlapping of the fillings was 0.52 +/- 0.44 millimeters on the teeth and 0.48 +/- 0.43 millimeters on the X-ray pictures. There was no significant difference between the values obtained by both methods. On the upper teeth [teeth: 0.64 +/- 0.50 millimeter, X-ray: 0.59 +/- 0.48 millimeters (significantly) P less than 0.001] the overlapping of the fillings was greater than on the lower ones (teeth: 0.39 +/- 0.49 millimeters, X-ray: 0.36 +/- 0.33 millimeters). The other comparisons did not show any significant difference by either method. The oro-vestibular extension of the overlapping gingival filling borders was, on the average 3.45 +/- 1.25 millimeters and amounted to 46.25 +/- 15.94% of the width of the surfaces. The percentual oro-vestibular extension of the gingival filling borders was significantly greater (p less than 0.05) on the premolars than on the molars. The gingivally overlapping filling showed also an oral and/or vestibular overlapping.

[Dental enamel hypoplasia apropos of a case]. / A zománchypoplasiáról egy eset kapcsán.

The developmental anomalies of dental hard tissues are relatively common in children. These anomalies can involve separately the enamel and they are due to many factors acting during odontogenesis. The paper deals with the main ethological factors and describes a case of idiopathic hypercalcemia. It is normally accompanied by aortic stenosis, mental retardation and a characteristic elfin face. This is called Williams syndrome. In this case we only found enamel hypoplasia on the cusps of the first molars.

[Variations of pathological tooth loss with special reference to tooth erosion--apropos of a case]. / A patológiás fogkopás fajtái, különös tekinttel az erosióra--egy eset kapcsán.

Importance of tooth surface loss has increased in dental practice. It is difficult to determine aetiological factors and the exact diagnosis, because the symptoms are often combined. The aim of the present study was to summarise the most important factors of tooth surface loss, mainly of erosion which is a frequent form. Reviewing the literature aetiological factors, symptoms, differential diagnostic problems and therapeutic advice are discussed. Prevention, early diagnosis and treatment are very important in these patients.

[Comparative study of the rheological properties of artificial saliva types based on hydroxy-propyl-methyl-cellulose (methocel) and carboxy-methyl-cellulose (CMC)]. / Hydroxy-propyl-methyl-cellulose (methocel) és carboxy-methyl-cellulose (CMC) alapú münyálak reológiai sajátságainak összehasonlító vizsgálata.

Apparent viscosity at different shear rates was measured for two types of saliva substitutes based on methocel and CMC, and was compared with that of human whole saliva. Results indicate, that fresh mixed human saliva is viscoelastic, exhibiting pseudoplasticity. Methocel containing artificial saliva and human whole saliva are similar in their rheological properties, while the preparation based on CMC is almost a Newtonian liquid. From the results it can be concluded that the saliva substitute containing 0.5% of methocel appears to be a better substitute for natural saliva than of containing CMC as far as rheological properties are concerned.

[DMF study on extracted deciduous teeth]. / A df-s vizsgálata extrahált tejfogakon.

The aim of the present investigation was to study the number of the carious surfaces of extracted primary teeth in order to determine component m in the dmf-s index. Altogether 903 deciduous teeth were examined under artificial light with a dental probe. The surfaces were evaluated separately. The examined teeth were divided into two groups according to the amount of root resorption. On the basis of the present study the following conclusion can be drawn: 1. The average of df surfaces of molars was 2.34, whereas it was 0.74 at the front teeth. The df number shows practically only caries, because filled surfaces were found in only 1.99% of the cases. 2. In any type of the teeth df lesions were the rarest on the vestibular and oral surfaces. 3. Caries (filling) was found most frequently on the occlusal surfaces of the upper and lower 1st molars. Caries (filling was the rarest on the vestibular surfaces of the upper 1st and 2nd molars. 4. The amount of root resorption did not show much influence on the df score. 5. During the calculation of the dmf-s average of the primary teeth the m value can be substituted for 2.0.

[Periodontal effects of the bridge and neighboring anchors, based on follow up studies]. / A hídtest és a szomszédos horgonyok parodontális befolyásoló hatása a követéses ellenörzés tapasztalatai alapján.

Two weeks after cementing in the dentures there is no evaluable difference in the Tm., the Pl. I. and the G. I. between the check-up examined surfaces on the approximal surfaces close to the bridge. Generally 8 months later a higher G. I. points on the approximal surfaces of neighbouring anchors by the employed periodontological examining methods. It means an unfavourable prognostic that the inflammation symptoms on the surfaces the second and third rate abutment teeth remained also after the prosthetic treatment to a similar degree.

[Instrumental analysis of sagittal condylar motion pathway]. / A condylus sagittalis mozgáspálya müszeres vizsgálata.

An analysis of protrusive jaw movement was carried out using Quick-Axis mandibular motion analyser. The condylar path tracings were recorded of 46 individuals (21 women and 25 men). Three recordings were performed on each side and a tangent to the condylar curves was drawn to calculate the condylar angle. Considering all dates the mean value of angulation was 52.2 degrees. There were no statistically significant differences between the two sexes and sides. The authors' findings suggest it is advisable to perform three consecutive registrations on each side and calculate a mean condylar angle to gain a better result.

[Reproducibility of the centric relation mandibular position]. / A centrális relációs állkapocshelyzet reprodukálhatóságának vizsgálata.

The centric relation (CR) is an important position either diagnostically or therapeutically. It is supposed to register the proper position of the mandible in a verifiable and reproducible way. This study addresses the reproducibility of the CR. Intra-oral graphic recordings were carried out in 15 dental students and the antero-posterior and medio-lateral positions of the point of the tracings were evaluated. The tracings were reproduced within an area 162 +/- 55 microns on sagittal axis and 141 +/- 32 microns on transversal axis. The other aim of the study was to investigate the effects of the graphic and the leaf gauge registrations on the condyle position of an articulator. It was concluded that there were no significant differences in reproducibility between the two methods on sagittal and transversal axes, but on the vertical axis the graphic registration method proved to be significantly more reproducible than the leaf gauge registration.

[Short-term effectiveness of fissure sealants]. / Barázdazárás hatékonyságának rövid távú vizsgálata.

Fluoride therapy is a widely accepted method of reducing smooth surface caries. Sealant therapy is intended to provide similar results for the occlusal surfaces of the teeth. In this study the retention of sealants was examined and a comparison was made between the caries rate in the group with sealed molars and controls after 12 months... The caries increment was significantly lower in the sealed group.