Biomedical subjects
Publications and source records attributed to A De Smit.
Analysing the cranio-facial complex is generally based on lateral headplates. On these radiographs, morphological descriptions are made based on distances and angles. In this article refinements allowing more extended and more exact skull analysis are proposed. The possibilities of three-dimensional recording, the skeleton theory and the finite element method will be discussed.
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.
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.
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A detailed inspection of the inner tooth morphology on röntgenogram is necessary as the surface morphology generally does not reveal the existence of an invagination. The irreversible pathological evolution occurring when diagnosis is neglected, should incite the practitioner to look for invaginations on every set of röntgenograms. Five therapeutic techniques are described. If an appropriate endodontic technique is applied, a successful root canal filling can be achieved.
There tooth abnormalities can be classified into four major groups, depending on the depth of the invagination. A typical example from group four is described. Thorough röntgenological examination reveals a frequent occurrence. The great diversity in nomenclature and the variety of morphogenetic and etiological theories show that genetic factors are very important in the development of an invaginated tooth and that knowledge concerning the pathomechanisms is very inadequate. A detailed inspection of the inner tooth morphology on röntgennogram is necessary as the surface morphology generally does not reveal the existence of an invagination. The irreversible pathological evolution occurring when diagnosis is neglected. Should incite the practitioner to look for invaginations on every set of röntgenograms. Five thereapeutic techniques are described. If an appropriate endodontic technique is applied, a successful root canal filling can be achieved.
These tooth abnormalities can be classified into four major groups, depending on the depth of the invagination. A typical example from group four is described. Thorough röntgenological examination reveals a frequent occurrence. The great diversity in nomenclature and the variety of morphogenetic and etiological theories show that genetic factors are very important in the development of an invaginated tooth and that knowledge concerning the patho-mechanism is very inadequate.
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