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ePaper created 2016-03-24, 17:16:09 | version 1.38.0
| research implants 1 201618 –– there is a unilateral missing tooth and the con trolateral incisor has normal and aesthetically pleasing proportions. The objective will be to create a lateral incisor implant that is a mirror image; –– with the same situation but where the contro lateral incisor is small; this is a situation that occurs frequently in unilateral agenesis where the incisor that is present is riziform or, if there is agenesis of both lateral incisors, the clinical examination should gather the information re quired to decide on the dimensions and coronal axes of the proposed lateral incisors. An analysis of the occlusion and the dimensions of the cen tral incisors are the clinical parameters that make it possible to establish the characteristics of the planned prosthetic teeth. The anatomy of the lateral incisor has been the subject of various publications, including, notably, by Papathanassiou6 who defined average dimen sions and a typical form (Fig. 3a) and also presented numerous morphological variants affecting these dimensions and also other characteristics such as the crown/root ratio and the coronal and root axes (Fig. 3b). These morphological criteria, which can now be found using 3-D imaging, have had a sig nificant influence on the location of implants in all spatial planes in order to achieve the goal of har mony of form and dimension. Other publications, such as those by Levin7 and Preston,8 make it pos sible to estimate the width of absent lateral incisors on the basis of the central incisors (Fig. 4). “Establish the ideal width and orientation of the planned prosthetic crown.” Implant location A clinically significant deficit signals the need for reconstruction of hard tissue but, conversely, a site without a tooth with no loss of volume should be subjected to a three-dimensional X-ray, as thick soft tissue can hide a lack of hard tissue (Fig. 5). A thin tissue biotype or a lack of attached gingiva can be a sign that gingival augmentation surgery will be required, particularly if a bone graft needs to be performed. Occlusion For orthodontic treatments, the anterior guid ance should be analyzed carefully. It can be tempt ingtoincreasetheperimeterofthemaxillaryarcade in order to obtain, at the least, implant corridors that are sufficiently wide at the level of 12 or 22. However, an overjet will make it very likely that the natural teeth will move in relation to the implant prosthesis with highly negative consequences for the sustainability of the cosmetic outcome. Documentation Taking photographs at the start of the treatment will make it possible to maintain a record of the initial condition, which is always useful if there are medical/legal problems at the end of the treat ment. In addition, the images often make it possi ble to see problems relating to width, axis or asym metry that sometimes go unnoticed during a clin ical examination. “Check anterior guidance and absence of overjet.” Complementary tests 2-D imaging Panoramic X-rays or retroalveolar radiography make it possible to check the depth of implantable Fig. 9: Diastemas created around a riziform tooth to obtain a space of 6 mm. Figs. 10a & b: Centered location of zenith of 22 (a) (arrow) to be taken into account when making the crown 12 (b). Fig. 9 Fig. 10a Fig. 10b 1201618