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Dental Tribune Pakistan Edition

CLINICAL PRACTICE 2015 Pakistan Edition DENTAL TRIBUNE 5 The guidelines of the European Association of Dental Implantologists[5] offer a critical discussion of angled and short implants. Angled implants require a bone quality above 3, 3-D planning and guided implantation, among others. Planning based on an impression with fabrication of a planning cast is critical for the final outcome of implant placement and thus for the procedure. This will determine the required treatment steps and desired treatment outcome. Quite often, this step is not accorded the necessary importance in daily practice. Adequate planning should be done by the dentist and a special appointment with the patient should be made to obtain consent. With two-step procedures, repeating planning after augmentation and a second 3-D radiograph may become necessary. Digital 3-D planning Today’s prosthetic planning possibilities offer alternatives to conventional casts. Two digital prosthetic planning tools will be discussed here, SimPlant (Materialise Dental) and SICAT/CEREC (Sirona). Both these tools are alternatives to the conventional approach described above via digital planning. With both methods, the surface of the neighbouring teeth and soft tissue is scanned and minor augmentation, longer prostheses are necessary for short implants, which are situated more lingually than the natural teeth. The use of short implants in the lateral jaw is subject to several restrictions, such as good bone quality, primarily connected crowns or caps, no extension bridges, no lateral excursion contacts and no para-functional habits. Angulation is limited to 20 degrees. Furthermore, angled implants are not recommended for a shortened row of teeth according to the guidelines of the European Association of Dental Implantologists.[5] If alignment is carried out with respect to antagonists in the natural dentition, positioning the new implant-borne crowns will not lead to any functional losses, unless the antagonists were not functionally situated in the dental arches originally. Space towards the cheeks must be regained, even if patients with a long case history sometimes complain about spontaneous cheek biting and bolus retention. One must choose carefully between the more pleasant approach of using short and angled implants with long crowns and the more difficult approach of bone augmentation. Three-dimensional planning provides indispensable information in cases like these. With reference to typical defect patterns, Figure 2 demonstrates that restoring bone volume for very different defects can be problematic. A typical reconstruction using a surgical guide for pilot drillings in a shortened row of teeth with good initial conditions is depicted in Figures 3a and b. Edentulous jaw Three-dimensional planning is of vital importance for determining the treatment approach for implantation in edentulous jaws. For instance, one has to decide upon whether and which augmentative measures are required and whether a removable or fixed prosthesis is suitable. With regard to the last point, it must also be decided whether extensive single-tooth replacement is possible, whether small or large bridges must be used, and whether a greater intermaxillary distance must be filled prosthetically by longer crowns or by a mucosa substitute. The number of implants for fixed dental prostheses include the All-on-4 concept (Nobel Biocare), the consensus conference recommendations of six implants in the mandible and eight in the maxilla, and tooth-by-tooth reconstruction up to the first molar. The multitude of planning information and treatment possibilities requires a great deal of planning, which is always justified because of its significant consequences. Planning based on digital casts is not appropriate in these cases, since the support of the cheeks and lips by the prosthesis is important and this can only be determined with the help of and for each patient. Here, the advantages of prosthetic planning are particularly evident. Edentulous jaws often require a special approach (see Figs. 4a & b for an example). Extensive augmentation is frequently necessary (Figs. 5a–f). The required length of the teeth, however, has to be clarified with the patient before treatment and depends on the amount of tooth displayed during lip repose (Fig. 5e). Quite frequently, implants are placed inter-foraminally in the mandible, often because extensive augmentation is still problematic in the lateral mandible. Figures 6a and b show a patient with six implants and an extension bridge. Even in cases of seemingly simple implantation for removable dentures in an edentulous jaw, 3-D planning and a planning cast are needed to verify functional reconstruction and soft-tissue support. In addition, they can aid determination of the positions of the implants in consultation with the dental technician and planning for adequate space for the attachment box. Discussion Three-dimensional planning for implants holds the advantage of higher quality owing to (a) risk identification; (b) planning reliability; (c) production of near-natural structures; (d) targeted and fast work; (e) patient compliance; and (f) cost transparency. These advantages are largely due to the greater amount and quality of information gained. Three-dimensional diagnostics enable us to obtain reliable information about the condition of the alveolar process and important anatomical structures. With the additional planning cast, information about the restoration of function and aesthetics is obtained. Combining both information sources will result in optimal treatment planning. In addition, an experienced surgeon can address surprises if the patient is flexible. Intra-operative decisions may also need to be made if unexpected situations arise. Knowledge of 3-D data permits planning, which entails devising a well-considered procedure and obtaining the necessary tools and substitute material, for example suitable implants and bone substitutes. Owing to the traceability of diagnosis and treatment, as well as the resulting safety, patients will regard the procedure particularly positively. A disadvantage is the higher initial outlay, but this is balanced by increasing use owing to a targeted and quicker workflow and thus less reworking. Implantation always requires a 3-D radiograph. These new techniques have greater logistical requirements than conventional dental procedures do and require extensive involvement of the teams involved in order to achieve treatment success. It should be borne in mind that every surgery is accompanied by a certain risk in spite of the safety precautions taken. In addition, too much confidence in methodologies may lead to carelessness. Errors may even arise with 3-D planning, which may hold negative consequences for treatment. Therefore, it is important to be familiar with each step and error source and thus expert training is crucial. In addition, maintaining a critical attitude throughout treatment is necessary to avoid errors. The advantages of 3- D planning are so significant that it has become indispensable. Editorial note: This article was published in cone beam_international magazine of cone beam dentistry 03/2014. A list of references is available from the publisher. January Fig. 5d: Radiograph after placement of the bridge Fig. 5e: Prosthetic result, lip repose Fig. 5f: Prosthetic result, lip raised. Despite augmentation, long crowns are were still required Fig. 5a: Two-step technique in a case of advanced atrophy of the alveolar process before prior to fixed prostheses. Horizontal and vertical augmentation Iintra-operatively, fixed bone block (left) and covered with membrane cover. Fig. 5c: Post-implantation Fig. 5b: Healed post-augmentation Fig. 6a: Loading of an edentulous mandible with a fixed bridge on inter-foraminal implants: Planning detail Fig. 6b: Four years post-treatment Fig. 7a: X-ray after implantation with mucosa-born drilling template in situ Fig. 7b: Surgical site with lingual position of the medial implants

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