Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2016-03-24, 17:16:09 | version 1.38.0
research | 1 2016 implants 19 bone in relation to the floor of the nasal cavity, the bone level in relation to that of adjacent teeth and the parallelism of the central incisor and canine. 3-D imaging 3-D imaging is required to check the vestibular palatal dimensions of the bone crest. There are three possibilities: –– the crest is sufficiently wide to take an implant without any bone augmentation; –– the crest is narrow, bone augmentation is re quired prior to siting the implant (Fig. 6); –– intermediate situations where the siting of the implant will be accompanied either by bone splitting or by guided bone regeneration. –– Orthodontic preparation When the adjacent teeth present apical conver gence, the orthodontic preparation should create a mesio-distal dimension at the level of the root that allows the implant to pass with a margin of at least 1 mm of bone (Figs. 7 & 8). Where there is a controlateral incisor of a normal size, the rule for the orthodontist is to measure the width of that tooth carefully and to recreate the same width in the crown of the planned implant. Where the con trolateral incisor is riziform, the orthodontist should plan the future face of the tooth in order to achieve two laterals with the same shape. Diastemas around the riziform tooth make it possible to achieve a smile that, in the end, is al most symmetrical (Fig. 9). The riziform incisor does not have to be in the centre of the space but should be positioned in such a way that the papillae and the future zenith of the tooth are optimized. The zenith should be located 0.4 mm distal from the centre of the tooth for a lateral incisor, according to Chu et al.9 (Figs. 10a & b). Sometimes, a zenith situated more than 1 mm from a line between the collars of the central incisor and the canine should be surgically altered by coronal lengthening as a lateral incisor that is too short can also be aesthet ically unacceptable. “The orthodontist should anticipate the future prosthetic morphology of the riziform incisor.” Hard tissue augmentation Where a bone reconstruction is indicated, this should take into account one of the key factors for the overall cosmetic outcome: restoration of pap illary support in order to avoid any unsightly black triangles between the lateral incisor and the adja cent teeth or any concave area above the implant crown that would create an ugly shadow. The cortical graft, taken from the chin or the external oblique, should be formed in such a way as to provide support for the gingival papillae (Fig. 11). Gaps under and around the graft should be filled with cortical bone particles, crushed from the chin block or lateral mandibular area using a bone mill. The attachment must be reliable. This is done using two 1.6 mm diameter osteosynthesis screws (Fig. 12). Autografts take about 5 months to heal. Fig. 11: Cortical graft in place, shaped to support future papillae (case as shown in Fig. 1). Fig. 12: X-ray result, compare with Fig. 6. Fig. 13: Clinical outcome five months after the graft. Compare with Fig. 11. Fig. 14: 3 mm diameter NobelActive implant. Figs. 15a & b: Papillary view (b), X-ray view (a), two years after the insertion of the implant. Fig. 11 Fig. 15a Fig. 15b Fig. 12 Fig. 13 Fig. 14 12016