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Biomedical subjects

L Dermaut

Publications and source records attributed to L Dermaut.

At least 37 records · Page 2Linked to original sources
PubMed1992

Comparison in shear bond strength of orthodontic brackets between five bonding systems related to different etching times: an in vitro study.

New adhesives are continuously being marketed. The adhesive-bracket bond is still the weakest point in orthodontic bonding. A new device for the measurement of shear bond strength values (SBS) of orthodontic brackets is presented in this article. With this device, five commercial products were evaluated for their SBS: Lee Bond (LB), Concise (C), Super C (SC), Achieve-no-mix (ANM), and Panavia Ex (PE). After applying Begg brackets of laminated minimesh on lower human incisors, the specimens were thermocycled. The products investigated produced high bond strengths. The products tested showed shear bond strengths that were significantly lower than those stained with PE. The application of PE yielded the highest shear values. Nevertheless, some characteristics of this product might be clinically somewhat inconvenient. There was no significant difference in shear bond strength between 15 and 60 seconds enamel etching before bond application.

Acid Etching, Dental↗
PubMed1990

The value of the macerated skull as a model used in orthopaedic research.

In this study a method was developed to enable the measurement of initial bone displacement in vivo, post-mortem, and in vitro. Speckle interferometry was used as measuring technique. Through the construction of the centres of rotation, the different orthopaedic effects could easily be compared. Also the magnitude of the bone displacement could be calculated. The initial post-mortem displacement of the maxilla corresponds very well with the initial in vivo displacement. After maceration and drying of the skull, however, clear differences from the in vivo displacement were found. The orthopaedic effects on a macerated skull can be manipulated considerably by changing, for instance, the degree of humidity. Only a limited number of skulls was examined in these experiments and probably still other variables exert an influence on the bone displacement in the macerated skull. Nevertheless, it is certain now that the dry skull cannot reliably be used as a model to simulate the initial bone displacement in vivo. The experimental set-up of this study will be used in the future to evaluate the effect of environmental factors (humidity, temperature, etc.) in an attempt to improve the value of the skull as a model for orthopaedic research. Moreover, this technique permits investigation of the link between initial displacements in vivo and longitudinal changes.

Aging↗
PubMed1990

[Rapid maxillary suture expansion].

Rapid maxillary expansion is a technique with an old but controversial history. Bio-mechanics and apparatus have largely involved over the years and the procedure is generally accepted. Discussion concerns only the patient age range on which the therapy is applicable. Fourteen to eighteen seems the accepted age limit. Three essential parameters determine the success of the expansion: degree of interlocking, synostosis and skeletal resistance from the surrounding osseous tissues.

Adolescent↗
PubMed1989

[Dental autograft: a supplementary dimension in dental practice].

This article deals with the possibilities and limitations of autogenous transplantations. In properly selected cases (trauma, missing teeth,...), this procedure might be a valuable alternative treatment. The indications for transplantation, the surgical technique, the recipient site and the choice of the transplant are discussed. The most important parameters which influence the success of a transplantation are: the stage of root formation, the atraumatic removal and insertion of the germ, the final position of the transplant and the post-operative fixation. Clinical examples will illustrate some indications.

Child↗
PubMed1985

The width of the attached gingiva during orthodontic treatment: a clinical study in human patients.

Studies of the influence of orthodontic movement on the width of the attached gingiva gave conflicting results. Therefore, it was decided to evaluate this parameter in human patients during a full orthodontic movement with fixed appliances. Retrusion of six maxillary anterior teeth was performed in thirteen patients scheduled in a prophylactic program that included a 2-week recall during the entire experiment. Before and after treatment the plaque index, the sulcus bleeding index, the width of the keratinized and the attached gingiva, and the marginal gingiva mobility index were measured. The results indicated that retrusion of the maxillary anterior teeth had no influence on any of the measured parameters.

Adolescent↗
PubMed1984

Soft-tissue profile preference.

The relative influence on profile preference of the anteroposterior maxillomandibular relation, the lower facial height, and the form of the dorsum of the nose is a source of interesting controversy. In order to obtain more information on this subject, twenty-seven shadow profile photographs were artificially constructed to represent the main characteristics of the nine profile types proposed by Sassouni combined with three different kinds of nose dorsum. Each series of nine profiles was ranked according to the personal esthetic preference of 249 adults (mean age, 23 years). One group of test persons (40 females and 91 males) had no orthodontic background, while another group (49 females and 69 males) had received some orthodontic teaching. Chi-square tests of significance showed no significant difference between male and female participants in esthetic preference for the sex of a profile. Also, the difference in orthodontic knowledge had no significant effect on esthetic preference. Nose dorsum changes induced significant differences only in Class II normal profiles; convex noses were less appreciated. Calculation of average preference values revealed that Class I normal profile types were clearly the favored ones, followed by Class I deep profiles. Open profile types, on the contrary, were obviously the least appreciated. This sequence indicates that, in profile evaluations, vertical profile characteristics could be more important than anteroposterior features and that a lengthening of the soft-tissue profile is not desirable in most cases. Seven weeks after the first ranking of male profiles, 193 persons were retested. The rank correlation values according to Kendall showed that one out of four persons ranked profiles significantly different in the retest.

Adult↗
PubMed1984

An histological investigation of invaginated human incisors.

The outlines of the invaginations resembled bottles with narrow necks directed at the incisal edge of the teeth. It is proposed that this form is genetically predetermined and that an active or passive infolding gives rise to the invaginations. In one case investigated out of six, an interruption of the dentin layer, surrounding the invagination, was found. This could become a susceptible site for post-eruptive bacterial invasion. In all cases, considerable amounts of enamel with normal structure were found in the invagination. The centrally positioned connective tissue was richly supplied with blood vessels and lined with layers of epithelial tissue, demonstrating various stages of an involutive enamel organ.

Dens in Dente↗