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H Fischer-Brandies

Publications and source records attributed to H Fischer-Brandies.

At least 19 recordsLinked to original sources
PubMed1992

[Increasing the adhesion of glass ionomer cements in bracket bonding].

For attaching orthodontic brackets glass ionomer cements are being discussed as an alternative material to synthetic glues since they are less aggressive toward the tooth enamel. A serious disadvantage consists in a lower degree of adhesion to enamel. The adhesion can, however, be increased to some extent by enamel preparation. In order to investigate further improvement in this area, 250 freshly extracted bovine teeth were treated with 22 chemicals and their enamel-conditioning properties were tested. For the attachment of the brackets the glass ionomer cements AqaCem and Ketac-cem are used. Tensile shear tests were carried out with a Wolpert universal testing machine. Best results were obtained with the aromatic carbonacids benzoic acid and salicylic acid in acetonic solution. The mean adhesive power was 9.8 MPa. This means an increase of 38% as compared to other pre-conditioning materials such as polyacrylic acid. It can be assumed, that aromatic carbonacids as small, very reactive molecules can establish a closer contact to the phosphate groups of enamel than can the macromolecular polyacrylic acid. Thus, a further step on the way to using glass ionomer cements as a bracket bonding material seems to have been taken.

Adhesiveness↗
PubMed1992

[The effect of the interocclusal space on temporomandibular recordings. A study with the use of the Stereognathograph PC].

1536 recordings of the condylar movement of 32 patients were made by means of the Stereognathograph PC. The test persons performed mediotrusive and protrusive movements. These movements were recorded with tooth contact and with increased interocclusal space, with and without the clinician's supportive guidance. The objective of the study was to analyse the effects of increased interocclusal space on the recording of the condylar path. Statistical evaluation showed that neither procedure has any real advantage over the other. Both, the occlusal tray as well as the paraocclusal tray may, depending on clinical situation of the ligaments, lead to erroneous recordings. The reproducibility of the recording of the condylar path is only slightly decreased by increased interocclusal space. Considering, however, the amount of work involved in each procedure, the occlusally fixated tray should probably be given preference, when there is no intention of recording occlusal guided movements.

Adult↗
PubMed1992

[The stereognathograph PC--test results with the new version of the device].

The PC stereognathograph was investigated for measurement errors in laboratory experiments on an optical bench as well as on an articulator. The values obtained were compared with the data of the predecessor model. A substantial reduction in the linearity in transverse measurements has been effected, so that these are now within acceptable limits. A variation of linearity factors which can be avoided by electronic fine adjustment still arises owing to incongruence of the six measurement channels. The hinge axis can be localized very well on the articulator. By and large, the announced correction of the projection error which we have demanded has not been implemented up to now. In view of the clear imaging of condylar movement in space and time on the monitor and the adequate precision of the clinical measurements effected, the PC stereognathograph appears to be a valuable system for instrumental diagnostics.

Dental Articulators↗
PubMed1991

[The accuracy of soft tissue profile prediction with the "Dentofacial Planner" in skeletal prognathism].

30 pre- and postoperative lateral cephalograms of patients with mandibular prognathism are used to evaluate the soft tissue profile prognosis given by the "dentofacial planner". As a result, the horizontal displacement of SLS (sulcus labrale superius) and Pg' (soft tissue pogion) in patients with a normal vertical dimension and additional LMF (labiomental fold) in persons with a marked overbite are calculated well. The horizontal changes of the other points analyzed as well as all vertical changes are not predicted satisfactorily in the momentary version 4.22 A (febr. 1989), which will be improved by the company.

Adolescent↗
PubMed1991

Castillo-Morales' orofacial therapy: treatment of 67 children with Down syndrome.

Infants with Down syndrome often present with a typical orofacial disorder, the features of which include hypotonicity of the perioral muscles, lips and chewing muscles, and a protruding tongue, later followed by active tongue protrusion, as well as problems with sucking, drooling, etc. This study presents the effects of Castillo-Morales' therapy with 67 Down syndrome children (average age at start of therapy 13.9 months), who wore the palatal plate intermittently for an average of 12.1 months. Significant positive results were obtained in spontaneous tongue position, upper and lower lip tonicity and position, mouth closure, drooling and sucking.

Child↗
PubMed1991

[Effect of different enamel structures on bonding of glass ionomer cements].

In the present study, the adhesive strength of glass-ionomer cement (GIC) for bracket bonding is analysed in relation to the surface characteristics of the enamel. The bonding of brackets to the enamel of impacted teeth as well as erupted teeth of adolescents and adults is determined in shear force experiments. The results of our investigation shows that GIC attaches to adult enamel to a significantly better extent than to the teeth of adolescents. The poorest values were shown in impacted teeth. It is shown with reference to scanning electron micrograms that surface lesions occur especially frequently in use of conventional etching technique on enamel in adults after debonding the bracket. GIC thus appears to be a promising alternative material for bracket fixation which does not damage the enamel, especially in adult orthodontics. In view of the result, its suitability should be checked in clinical studies.

Acid Etching, Dental↗
PubMed1991

[Fluorine distribution in the enamel in the use of glass ionomer cements as bonding materials].

The rise in the fluorine content of dental enamel after bonding orthodontic attachments with glass ionomer cement (GIC) was analysed in an in vitro study. Twenty-four freshly extracted caries-free premolars from adolescent patients were available for investigation. The teeth were cleaved longitudinally in the oro-vestibular direction to obtain a test specimen and reference sample. The GIC Aquacem was used as bonding material. The fluorine was measured with an electron beam microprobe (Camebax SX 50) 10, 20, 40 and 80 days after bonding. A rise of fluorine in dental enamel of more than 120% was observed after the bonding procedure. This rise was especially rapid in the first ten days, and a saturation value was reached after 40 days. The depth of penetration into the dental enamel was 20 microns, and the surface spreading was at least 3 mm. An equilibrium state is attained between the 40th and 80th day. A preventive action on caries in the vicinity of attachments bonded with glass ionomer cement is to be expected owing to the accumulation of fluorine in the dental enamel.

Adolescent↗
PubMed1990

[The determination of suitable film-screen cassette combinations for orthodontic x-ray technics].

16 film-screen cassette combinations (FSCC) were compared with regard to their detail sharpness and the radiation dose required. After standard adjustment to a uniform average optical density, the contrast and detail were analysed using a self-constructed microdensitometer. The following results were found; on average there is a 14.5% dose reduction using carbon fiber cassettes compared with aluminium cassettes. FSCC with especially low exposure time are: Cronex 2, fast detail, Du Pont (0.4 sec); Cronex 2, NPU, carbon fiber cassettes (0.5 sec); Curix RP1, NPU, carbon fiber cassettes (0.64 sec). The loss of quality associated with this and measured with the microdensitometer is insignificant for clinical orthodontic purposes. This study concludes that differences in contrast and detail do not justify the use of cassette combinations which require a high dose of radiation.

Evaluation Studies as Topic↗
PubMed1990

[Predictability using the "Dentofacial Planner Version 4.22 A" of soft tissue changes following adult orthodontic treatment].

For the prediction of profile changes following orthodontic treatment the computer program "Dentofacial Planner" (DFP) which bases on cephalometric measurements is available. The object of this study is to analyse the precision of the DFP version 4.22 A (release Feb. 89). The material of the study consists of the lateral cephalograms of 33 patients treated for maxillary incisor protrusion. In order to evaluate the ensuing profile changes certain cephalometric parameters are measured pre- and post-therapeutically. They are compared to the values predicted by the DFP. Statistical analysis yields the following results: 1. Clinically acceptable precision was found for seven of the 20 cephalometric parameters. 2. In two of the six parameters stated to be stationary by the DFP notable changes were found in reality. 3. The most accurate prognosis was made for the upper lip profile; the least precision was found for the lower lip. According to the manufacturer the results of this study will be included in alternations of the DFP program so as to achieve improvements in the criticized areas.

Adult↗
PubMed1990

[Reproducibility of hinge axis localization by stereognathography].

The program of the Stereognathograph V for localization of the hinge axis has been experimentally verified. Auxiliary recording devices have been mounted on an articulator and the process of localization has been simulated. On an average, the joint axis can be located in the articulator with an accuracy of 0.6 mm. In individual cases, errors may be up to 1.5 mm.

Dental Articulators↗
PubMed1990

[Linearity and error correction of the Meyer/dal Ri hinge axis measurement system].

Measurement errors inherently related to the instrument and those due to external factors were analysed for the SAS hinge axis measurement system in conjunction with the digital recording system. An optical bench served as measurement apparatus. Linearity errors are substantially less than 0.1 mm and thus of no clinical relevance. A slight reduction in the size of the movement coordinates imaged with slight incongruences of the six measurement canals results from erroneous calibration. The recording system proves to be insusceptible to interference by external factors in practical application. The projection error correction we investigated experimentally was satisfactory. Merely the processing quality of the electrical wiring attached to the measuring foils was not fully satisfactory.

Dental Articulators↗
PubMed1989

[The time of eruption of the milk teeth in Down's disease].

In the literature, the time of emergence of milk teeth in patients with Down's disease is reported to be delayed. However, only a few authors can document this observation in controlled studies. This occasioned a fresh analysis of the time and sequence of the milk dentition. In 93 babies and infants with Down's disease, the time of emergence of 842 milk teeth was recorded. In the statistical analysis, mean and standard deviations were calculated: by means of analysis of variance, left-right differences and sex differences were tested. There are the following results: the emergence of milk teeth begins with an average time delay of six months. The first milk molars frequently emerge as the first or second tooth. Sex differences and differences between right and left with regard to the emergence of milk teeth cannot be demonstrated. Overall, the sequence of emergence is very variable. The delayed emergence of milk teeth must be regarded as a component of the general delay in development in Down's disease which in the region of the head affects both the growth of the jaw and the development of the motor activity of the mouth.

Aging↗
PubMed1989

[Glass ionomer cements used as bonding materials in orthodontics].

The objective of the present study is to test the suitability of glassionomer cements quantitatively for bracket bonding. Premolar brackets were fixed under oral conditions with the following luting glassionomer cements on freshly extracted premolars of adolescent patients: FUJII (GC Dental Industrial Corporation, Tokyo); KETAC CEM (Espe, D-8031 Seefeld); AQUACEM (De Trey, Zürich). Enamel conditioning was carried out with polyacrylic acid, tannic acid and tubulizid (Dental, Therapeutica, S-Nacka). A conventional acid etching technique using concise (3M, D-4040 Neuss) was carried out as a control. The tensile bonds strengths were measured using a Wolpert universal test machine (no. T ZZ 707). In unconditioned enamel, the bond strengths of AQUACEM and KETAC CEM are significantly (p = 0.001) in excess of that of FUJII. By enamel conditioning, the bonding can be raised to a mean value of 6.8 MPa (AQUACEM), attaining about 60% of the values in conventional acid etching technique. The enamel consistency after debonding is discussed with reference to scanning electron micrograms. The results indicate that glassionomer cements should be tested as bracket bonding material in clinical studies.

Acid Etching, Dental↗
PubMed1989

[Vertical development of the jaw in cases of trisomy 21: interaction of form and function].

With reference to lateral tele-X-rays of 1896 patients with trisomy 21 in the period from birth up to the 14th year of life, the vertical development of the face was analysed. 1154 healthy children of the same age serve as control group. Particular attention is paid to the question as to the importance of parafunctional forces which derive from the lingual protrusion typical for trisomy 21. In the context of the statistical analysis, group differences were tested by means of analysis of variance. There were the following results: the hypoplastic development of the midface also involves the vertical dimension. There is a reduced caudal development of the maxilla; the horizontal positioning of the maxilla is only altered slightly in that the maxilla is depressed somewhat less posteriorly; the mandible shows a slightly hypoplastic development, and the mandibular angle is slightly reduced in size; an increased presence of a vertical growth type is not found; the parafunctional force deriving from the lingual protrusion do not have any demonstrable effect on the vertical skeletal development, but bring about a bialveolar protrusion of the incisors; the frontal vertical open bites found in trisomy 21 are mainly dento-alveolar in nature.

Adolescent↗
PubMed1989

[Error sources in recording three-dimensional mandibular movements. An in vitro study using the V-type stereognathograph].

The instrument-induced measurement errors in V-type stereognatography have been analyzed. An optical bench was used as a measurement apparatus. In measuring not too small movement distances, the linearity errors remained within acceptable limits. The variations in linearity due to calibration errors were almost negligible. In practical applications, the stereognatography proved to be insensitive to external factors such as type of illumination, room temperature and voltage fluctuations. Factors affecting the effectiveness of the projection error correction system, such as tilting of the filter, different sites of measurement of the six optoelectronic canals, and mandibular protrusion during mediotrusive movements, might be reduced by slight modifications of the measurement system.

Cephalometry↗