Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2016-09-22, 10:58:51 | version 1.38.0
science & practice 25th EAO Annual Scientific Meeting 15 that the natural teeth will move in re- lation to the implant prosthesis with highly negative consequences for the sustainability of the cosmetic out- come. 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 treatment. In addition, the images often make it possible to see problems relating to width, axis or asymmetry that sometimes go un- noticed during a clinical examina- tion. Complementary tests 2-D imaging Panoramic X-rays or retroalveolar radiography make it possible to check the depth of implantable bone in rela- tion to the floor of the nasal cavity, the bone level in relation to that of adja- cent 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 possi- bilities: – the crest is sufficiently wide to take an implant without any bone aug- mentation; – the crest is narrow, bone augmenta- tion is required prior to siting the implant (Fig. 6); – intermediate situations where the siting of the implant will be accom- panied either by bone splitting or by guided bone regeneration. – Orthodontic preparation When the adjacent teeth present apical convergence, the orthodontic preparation should create a mesio-dis- tal dimension at the level of the root that allows the implant to pass with a margin of at least 1mm 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 controlateral 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 almost sym- metrical (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 0.4mm distal from the centre of the tooth for a lat- eral incisor, according to Chu et al.9 (Figs. 10a & b). Sometimes, a zenith sit- uated more than 1mm from a line be- tween the collars of the central incisor and the canine should be surgically al- tered by coronal lengthening as a lat- eral incisor that is too short can also be aesthetically unacceptable. Hard tissue augmentation Where a bone reconstruction is indicated, this should take into ac- count one of the key factors for the overall cosmetic outcome: restoration of papillary support in order to avoid any unsightly black triangles be- tween the lateral incisor and the ad- jacent 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 us- ing a bone mill. The attachment must be reliable. This is done using two 1.6mm diame- ter osteosynthesis screws (Fig. 12). Autografts take about 5 months to heal. Ideally, the implant should be inserted between 4.5 and 5.5 months after the graft (Fig. 13). Insertion of implant Choice of implant The mesio-distal dimension of the gap will determine the choice of the implant. When this is close to or less than the average size of 6.5mm, the bone and papillary volume around standard size implants will be limited. According to Hasan et al.10 and Bourauel et al.,11 the disadvantage of small diameter implants is that they transmit higher stresses to the crestal bone than do standard implants. When replacing a lateral maxillary in- cisor, it is possible to arrange both the anterior guidance and the deduction in such a way as to make them largely affect the natural teeth, in the absence of any significant malpositioning, and in this way reduce the stresses applied to the implants. Under these condi- tions, small diameter implants have the advantage of increasing surround- ing residual bone volume as well as space available for papillary healing. In a forthcoming study of 120 NobelActive 3mm diameter implants, one of the conclusions confirmed the importance of these small diameter implants as regards the additional height of the papillae, resulting in an improvement in the Fürhauser pink aesthetic score12 (Figs. 14, 15a & b). 3-D positioning As regards replacement of a lat- eral maxillary incisor, the tolerances for the location of the implant are very small because of the narrow width of the implant corridor. Two re- cent meta-analysis13,14 concerning the precision of surgical guides resulting from 3-D imagery, even if these do not apply specifically to the lateral inci- sor replacement, has found a devia- tion in the order of a millimetre at the point the implant emerges and 4 to 5 degrees as regards the drilling axis. For Van Assche et al.,14 the aver- age imprecision at the apex of the im- plant is 1.24mm. Since these measurements are in- compatible with a 12 or 22 implant corridor, it is important to check the first drill hole(s) during the operation, whether the surgery is guided or be- ing carried out freehand. If the im- plant clinic does not have retro- Fig. 9 Fig. 10a Fig. 10b Fig. 9: Diastemas created around a riziform tooth to obtain a space of 6mm. Figs. 10a & b: Centered location of zenith of 22 (a) (arrow) to be taken into account when making the crown 12 (b). 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: 3mm diameter NobelActive implant. Fig. 11 Fig. 12 Fig. 13 Fig. 14 Figs. 15a & b: Papillary view (b), X-ray view (a), two years after the insertion of the implant. Fig. 15a Fig. 15b Fig. 16 Fig. 19 Fig. 20 Fig. 21 Fig. 17 Fig. 18 Fig. 16: Mobile Anyray 2 (VATECH) X-ray generator. Fig. 17: Intraoperative X-ray, Precision Drill inlay (left on picture) and in situ (right on picture). Fig. 18: Clinical outcome five months after the graft. Postoperative X-ray NobelActive 3/0 implant and 15° abutment in place. Fig. 19: Initial situa- tion. Fig. 20: De-epithelialisation of a palatal flap into a diamond shape. Fig. 21: Unfoldment of palatal flap, vestibular edge. Fig. 22 Fig. 24 Fig. 25 Fig. 26 Fig. 22: Creation of flap envelope, Swann-Morton blade through the envelope. SM 63, inlaid with transparency. Fig. 23: Passage of suture through the envelope. Fig. 24: The palatal flap is folded into the vestibular envelope using a suture thread. Fig. 25: Tissue integration with ceramic crown. Fig. 26: Vestibular bulge obtained with modified flap. Fig. 23