Complex implant-supported rehabilitation from the temporary to the definitive restoration

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Complex implant-supported rehabilitation from the temporary to the definitive restoration

7.1 Introduction

Over the past two decades, the indication range for osseointegrated oral implants has been significantly extended. This is due to progress made concerning the macro design and microstructure of implants, improved surgical protocols, and the introduction of new techniques and materials for efficient augmentation. As a consequence, implant-retained restorations have emerged as a standard treatment option.2,3,36,56,63,93 In many cases, however, patients suffer from a significant loss of hard and soft tissue, which may occur due to periodontitis, chronic periapical infection, ill-fitting dentures or trauma.29 In spite of more recent concepts that involve, for example, short or narrow implants to avoid augmentation,6,31,58 implant placement into existing bone without the preceding treatment of hard and soft tissue defects can be regarded as problematic.83,85 The requirement to restore deficient tissue is also based on the concept of restorative-driven implant placement, which has become the treatment gold standard.13,19,34,57

The contour of the alveolar ridge can be reestablished using an array of methods, including sinus floor augmentation, horizontal and vertical augmentation with bone blocks or guided bone regeneration, distraction osteogenesis, and ridge expansion techniques.4,7,18,22,49-51,53,54, 59,65,75,78,80-82,84 The concept of three-dimensional (3D) alveolar ridge reconstruction with the aid of thin cortical intraoral bone grafts and autogenous cancellous bone has been described in Chapter 4.

7.2 Specific aspects of temporary restorations

Undisturbed ossification of the augmented area is critical for the success of horizontal and vertical augmentation.53 The area must not be loaded by the temporary restoration, as loading would inevitably lead to resorption or loss of the graft.53 This, in turn, would result in an inadequate bone volume for implant placement, which finally may affect the functional and esthetic restorative outcome. During the first phase of osseointegration, loading of the implants with mucosa-supported provisional restorations should also be avoided as this could lead to the loss of osseointegration.77 Therefore, mucosa-supported provisionals are contraindicated in connection with complex augmentation (Fig 7-1a) and implant restorative procedures.53

The avoidance of a temporary denture affects patients both functionally and esthetically, considering that the period from initial surgery to final soft tissue shaping can extend over an entire year.52 As edentulousness is generally not accepted in the professional and private environment of most patients today, even for a short period, many patients still refuse implant treatment, thus denying themselves oral rehabilitation. If certain criteria are met, the insertion of a removable temporary prosthesis may be an option. However, this may also involve a certain postoperative period without restoration, the need to reline the denture with soft silicone, the inherent risk of microbial contamination and subsequent infection of the augmented area, and esthetically problematic retentive clamps.15

Since Ledermann’s investigations in the 1970s, high success rates have been demonstrated for immediate functional loading of splinted implants.11,61 More recent developments concerning implant macro-design and microsurface structure have extended the indication range for immediate or early functional loading.92,113 Implants, alone or in combination with natural teeth, can be used for the quadrangular support of an immediately loaded labside provisional.20,30,52,7779,86,92,108 In this way, patients in need of a complex rehabilitation, including augmentation, will benefit from a functional and esthetic provisional over the entire treatment period. However, to prevent excessive micro motion and ensure osseointegration, all implants should be rigidly splinted.43,46,100,101,113

Since the 1990s, one-piece screw-type conical implants have been reported as an option for the support of temporary restorations.12 Immediately loaded transitional implants, including so-called needle implants, have demonstrated good survival rates in a number of studies.11,12,20,21,23,26,38,52,86,90,92,96,100,107 Hybrid splinting of teeth and transitional implants has also been considered.27 By definition, these implants have to be removed before the final restoration is placed (Fig 7-1a to h).

Alternatively, permanent narrow-diameter implants can be used for immediately loaded provisionals. After successful osseointegration, these implants can be included into the final implant-retained restoration. This approach has likewise demonstrated good results.5,22,24,33,104,110

Long-term provisionals can be modified in the course of treatment. For this reason, they are an excellent tool to meet patients’ esthetic preferences, which may change over time.12,108 Apart from providing pure function, long-term provisionals include all the relevant information relating to the final restoration. These provisionals can be used as a test for the augmentation of the reduced vertical dimension in cases of severe abrasion of the remaining teeth.

In cases where the temporary restoration fulfills patients’ desires from the esthetic and comfort points of view, they can also serve for the planning of the definitive restoration. In this sense, a duplicate of the provisional may be used as an optimal drilling template.25 Finally, long-term provisionals have proven to be a helpful tool to shape the emergence profile in the final soft tissue surgical phase.108,114

Clinical indications for labside long-term provisionals supported by transitional implants include:

image Extraction of several teeth, leaving no other (or poor) support for the temporary restoration.

image Severe periodontal disease, including remaining teeth with a poor prognosis.

image Protection of grafted areas.

image Implantation/bone augmentation in edentulous jaws.

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Fig 7-1a Panoramic radiograph showing results after lateralization of the mandibular nerve, harvesting and grafting of retromolar bone blocks, and placement of three one-piece transitional implants to support the provisional restoration. The apical part of a fractured transitional implant remains to be removed (arrow). The blade implant in the fourth quadrant had been placed 10 years earlier.

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Fig 7-1b The transitional restoration is supported by the blade implant and three transitional implants.

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Fig 7-1c Healthy soft tissue after removal of the long-term temporary bridge.

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Fig 7-1d Removal of the fractured implant by means of a bony lid.

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Fig 7-1e Repositioning of the bony lid.

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Fig 7-1f Implant insertion in the grafted area.

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Fig 7-1g Final restoration in place.

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Fig 7-1h Panoramic radiograph after the final restoration and removal of the transitional implants.

The phase of the final prosthetic rehabilitation begins after the successful osseointegration of all implants in the augmented areas. The concept developed by Khoury involves loading of implants in the augmented areas after only 3 to 4 months.48,50,54 For a successful outcome and for long-term implant survival, the final restorative procedure must be safe and reliable. In this context, the passive fit of the suprastructure is a basic requirement. An adequate method was defined by Pape and coworkers in the 1990s.76 Transitional implants must be able to support the long-term provisional until the final restoration is placed. The following section presents in detail the restorative concept of the authors for complex cases where multiple and different bone augmentation procedures were necessary. With a minimal number of sessions, this concept offers maximum patient comfort and high predictability, with functionally and esthetically satisfactory implant-supported provisionals over the entire treatment period.

7.3 Treatment planning

Successful implant-retained restorations depend mainly on strategic treatment planning, which is based on comprehensive diagnostics.13,94,95 Before the onset of extensive treatment, it should be established whether the patient would prefer a removable denture with partial palatal coverage or a removable bridge without palatal coverage. Most patients prefer a fixed implant-retained bridge, even in cases with a high atrophic maxilla or mandible. In order to provide comprehensive advice, clinicians should overlook the possibilities and limitations of current surgical and prosthodontic concepts.

Concerning imaging modalities, conventional panoramic radiography, lateral cephalography, and dental radiographs are usually sufficient to evaluate potential abutment teeth. The use of CBCT should be left for the augmentation planning, after the cleaning and extraction therapy.

In some complex cases, facial analysis by means of profile and frontal photographs will improve strategic treatment planning. On the basis of these images, patients can be informed about potential tissue deficiencies that will have an impact on the restoration type (e.g. fixed versus removable). In terms of esthetics, the smile line is a critical parameter.95 In patients with a low smile (lip) line, i.e. when this line is on the level of the incisal edges, esthetic requirements will be easier to handle than in patients with a high smile line. In the latter case, optimal esthetic results should be the treatment goal, which implies significantly higher diagnostic and therapeutic effort.

To detect craniomandibular disorders, temporomandibular joint (TMJ) function should be thoroughly evaluated before starting the surgical treatment in complex restorations. Important information can be acquired from centric check-bites, arbitrary registration of the TMJ position, and study models mounted in a semi-adjustable articulator. With the help of these diagnostic devices, the dental technician can prepare a wax-up. This is important for the final details of the long-term provisional, especially when a fixed restoration is planned in the maxilla. The wax-up or diagnostic tooth arrangement helps the patient to participate in the restoration planning and therefore represents an important informational basis for the entire treatment.

Besides functional and tooth-related factors such as caries and endodontic problems, the periodontal prognosis of all remaining teeth should be carefully evaluated; their prognosis can, for example, be categorized as good, unreliable or hopeless. Teeth with a good prognosis can be included in the long-term provisional and the final restoration, and those with an unreliable prognosis might serve as transitional abutments during the temporary phase (Fig 7-2a to d). Teeth suffering from severe periodontal disease and important loss of periodontal attachment are categorized as hopeless and should be removed at the beginning of treatment. Whenever possible, natural teeth with a good prognosis should be retained in order to provide patients with some degree of proprioceptive control. As a rule, all decisions concerning retention or extraction of teeth should be based on the available literature28,37,41,42,44,64,6669,9799 as well as the clinician’s own judgment and expertise.

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Fig 7-2a Strategic triage of all teeth in relation to their prognosis.

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Fig 7-2b Panoramic radiograph taken after periodontal treatment, preparation of teeth, and insertion of strategic permanent implants to support the long-term provisional.

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Fig 7-2c Radiographic control after insertion of the fixed labside long-term provisional.

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Fig 7-2d Panoramic radiograph 1 year after the final restoration. All implants that supported the immediately loaded provisional were utilized for the final restoration.

On the basis of all diagnostic information, including the results of study model analysis, the patient should receive comprehensive guidance concerning the envisioned treatment and options for the final restoration.

7.4 Classification of temporary restorations

Cases where patients are to receive a fixed long-term provisional on the basis of the final design of the definitive restoration need very precise planning. Ideally, provisionals should have a quadrangular support. For this purpose, the provisional can be retained exclusively on the teeth, on the teeth and implants, or exclusively on the implants (Fig 7-3a to c). After removing teeth with a hopeless prognosis during the initial treatment phase, potential abutment teeth can be categorized as follows (see Chapters 2 and 4):

image Teeth to be included in the final restoration.

image Teeth to support the long-term provisional during the surgical phase, but not to be included in the final restoration (temporary abutments).

The types and positions of implants used to support the provisional should be planned with care. In very narrow alveolar ridges, one-piece transitional implants with a small diameter (1.5 to 2 mm) are indicated (Fig 7-4a to p). The ideal positions of the transitional implants in an edentulous jaw are the lateral incisor and first premolar. In this situation, it is possible to prepare a temporary restoration that fills the esthetic window from the right second premolar to the left second premolar. At the same time, it is possible to later insert implants in the canine area, which is an important key for the definitive restoration. Basically, one- or two-piece conical transitional implants can be used. As they quickly lose their congruity with the implant bed upon unscrewing, these implants are easy to remove (Fig 7-5a to t). Transitional implants are composed of an implant body with bone-compressive properties and a transmucosal conical head, which serves as a retentive element for the provisional.

As far as immediate loading supporting temporary restorations is concerned, permanent implants with a reduced diameter (3.0 to 3.4 mm) have demonstrated good results in the context of complex augmentation procedures. If successfully osseointegrated, they can also be included in the final restoration (see Fig 7-2a to d). However, depending on the final restorative concept, these implants may have to be removed at a later stage if they were not placed at the esthetically desired position. The use of a surgical guide from the beginning will prevent such inconvenience. Adhesive bridges are another temporary option after complex augmentation procedures. These restorations are retained by natural teeth, either in combination with implants or not (Fig 7-6a to l). The simplest type of provisional is a thermoformed splint with resin teeth (Fig 7-7). This option, however, results in significantly reduced comfort for the patient and a disturbance of the occlusion if used for a long time.

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Fig 7-3a Fixed temporary restoration, supported exclusively by the implants.

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Fig 7-3b Temporary restoration supported by the teeth and implants.

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Fig 7-3c Long-term provisional in the mandible, supported by the natural teeth.

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Fig 7-4a Panoramic radiograph showing significant resorption of the entire maxillary alveolar ridge.

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Fig 7-4b Reflection of flaps confirms vertical and horizontal bone loss.

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Fig 7-4c Prior to augmentation, transitional implants have been placed into the remaining bone.

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Fig 7-4d The alveolar process has been reconstructed with the aid of several bone blocks stabilized with osteosynthesis screws.

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Fig 7-4e Postoperative radiograph.

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Fig 7-4f Occlusal view of the provisional.

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Fig 7-4g The patient is pleased with the esthetic result of her fixed long-term provisional at the time of dismissal from the clinic.

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Fig 7-4h Clinical finding 4 months after the augmentation procedure. The transitional implant is mobile at the position of the maxillary first left premolar.

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Fig 7-4i Augmented area showing successful regeneration. A vertical bony defect is visible in the area of the disintegrated implant.

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Fig 7-4j Insertion of several XiVE (Dentsply Sirona) implants in prosthetically optimal positions.

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Fig 7-4k The loose transitional implant is substituted with a permanent one.

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Fig 7-4l The implant holder (TempBase; Dentsply Sirona) of the permanent implant remains in place to support the existing long-term provisional.

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Fig 7-4m The temporary restoration is modified at the position of the immediately loaded permanent implant, which replaces the failed transitional one.

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Fig 7-4n Panoramic radiograph after implant placement in the grafted bone.

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Fig 7-4o Panoramic radiograph 4 years after insertion of the final restoration.

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Fig 7-4p Panoramic radiograph 18 years postoperatively.

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Fig 7-5a Panoramic radiograph of a 65-year-old female patient showing significant resorption of the alveolar ridges in the maxilla and mandible.

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Fig 7-5b Lateral cephalograph prior to bone harvesting from the chin area.

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Fig 7-5c Bone harvesting from the chin with the MicroSaw.

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Fig 7-5d Clinical situation after bone harvesting from the chin. The harvesting procedure can be extended until the lingual cortical bone wall.

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Fig 7-5e Insertion of five implants in the interforaminal region.

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Fig 7-5f The implant surface is covered with a thin layer of autogenous bone chips.

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Fig 7-5g The harvested area is filled with collagen fleece and covered with a bone substitute material.

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Fig 7-5h Four transitional one-piece implants are inserted into the resorbed maxilla to support the immediate provisional.

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Fig 7-5i Bilateral augmentation of the sinus floor with simultaneous placement of four permanent implants. The alveolar crest is augmented with a bone block graft.

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Fig 7-5j View of the left maxilla with the grafted bone block and the provisional implants.

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Fig 7-5k Postoperative radiograph.

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Fig 7-5l Lateral cephalograph, additionally documenting the site of bone harvesting in the chin area.

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Fig 7-5m Clinical view of the long-term provisional fixed on four transitional implants.

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Fig 7-5n Clinical appearance 4 months postoperatively documenting the amount of regeneration.

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Fig 7-5o After removal of the titanium membrane, an implant of 4.5-mm diameter is inserted in the canine area.

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Fig 7-5p Similar situation in the left maxilla.

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Fig 7-5q Clinical aspect after implant exposure and removal of the transitional implants prior to placement of the final restoration.

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Fig 7-5r Frontal view of the final fixed prostheses in the maxilla and mandible.

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Fig 7-5s Radiographic control 8 years after the final rehabilitation documenting stable marginal bone levels around the implants.

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Fig 7-5t Lateral cephalograph confirms the reestablishment of the metal bony contour.

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Fig 7-6a Initial situation in the anterior mandible of a 45-year-old female.

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Fig 7-6b Clinical appearance after releasing a flap and extracting two left incisors. The two implants have already lost a substantial amount of their bony support.

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Fig 7-6c The implant at the position of the right central incisor is removed and a new implant placed at the position of the left lateral incisor. The missing bone is reconstructed with bone blocks harvested from the chin area after decontamination of the surface of the remaining implant at the position of the right lateral incisor. A titanium membrane is used to cover the graft donor site.

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Fig 7-6d Postoperative radiograph.

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Fig 7-6e A provisional bridge is stabilized on the TempBase abutment of the implant on the right side and on etched support on the left canine.

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Fig 7-6f Clinical situation with the temporary restoration.

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Fig 7-6g Insertion of an additional implant in the wellregenerated bone 3 months postoperatively.

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Fig 7-6h Postoperative radiograph.

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Fig 7-6i Clinical appearance of the final restoration with a full-ceramic bridge.

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Fig 7-6j Control radiograph 1 year after the final restoration.

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Fig 7-6k Clinical aspect 6 years after the restoration. A soft tissue graft was performed to reduce the muscle activity in the region.

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Fig 7-6l Control radiograph 6 years postoperatively.

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Fig 7-7 Thermoformed splint with resin tooth at the position of the central incisor, used as a long-term provisional.

7.4.1 Treatment procedure

Interim implants are conical titanium compression screws with a rough surface and a coronal diameter between 2.0 and 3.0 mm. They have a transgingival design and are available as one- or two-piece implants. A benefit of two-piece implants (e.g. Tempion interim implant; GZG, Cologne, Germany) is the possibility of removing the abutment for surgical or restorative reasons, especially during the preparation of the final restoration (Fig 7-8a to g). Unfortunately, this implant is not delivered anymore since the company stopped producing them. As an alternative, a new temporary implant (Medical Instinct, Bovenden, Germany) was developed in the last 5 years with the aim of fulfilling the need to support functional and esthetic temporary restorations, especially in very complex situations. The new two-piece implant system is available in two lengths (10 and 12 mm) and offers additional straight or angulated abutments to allow for all types of prosthetic restorations, including for extreme and difficult situations (Fig 7-9a to u).

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Fig 7-8a Tempion two-part temporary implant.

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Fig 7-8b Implant length can be reduced with a diamond disc.

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Fig 7-8c The reduced length depends on the remaining bone height.

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Fig 7-8d The temporary implant is inserted in the interdental septum after extraction of the teeth.

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Fig 7-8e The amount that the universal abutment is reduced depends on the occlusion.

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Fig 7-8f Control radiograph with the temporary restoration stabilized on two provisional implants in the posterior right mandible without any mechanical disturbance of the grafted site.

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Fig 7-8g Control radiograph with the definitive restoration. A fracture of the distal temporary implant occurred during implant removal. The fractured part is left in the mandible to avoid an additional surgery for the 75-year-old patient.

In cases where natural teeth are still present, a decision has to be taken regarding which teeth can be retained temporarily to support the fixed restoration. In every quadrant, two abutments are needed to support a resin-fused-to-metal restoration, closing the esthetic window and extending from the second premolars on both sides. In cases where no adequate natural teeth are present to support the temporary bridge, interim implants (minimum insertion torque 35 Ncm) can be inserted in strategic positions to support the restoration. However, during the extraction of hopeless teeth with significant bone loss, it is often very difficult to find sufficient bone into which the interim implants can be inserted in the ideal position. Therefore, some compromises must be made in order for the patient to have a fixed restoration during the healing period.

As interim implants have a conical shape with a coronal diameter between 2.0 and 3.0 mm, they can be inserted in the interdental septa or in the lingual/palatal bone of the socket. Following the extraction of the teeth and insertion of the interim implants, impressions are made with silicone-based material. The patient receives a chairside short-term temporary restoration, which is retained by the remaining teeth and the interim implants (see Fig 7-9l). One day later, the functional parameters of the long-term temporary restoration are recorded, and an esthetic setup is made. The metal-reinforced resin restoration can then be finished by the laboratory within 24 h. The main surgery with bone grafting and implant placement is usually carried out 6 to 8 weeks after this first step.

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Fig 7-9a A modern compact kit (Medical Instinct) for temporary restorations, including minimal instrumentation, a wide variety of abutments, and the implants in two lengths.

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Fig 7-9b Newly developed temporary implant (Medical Instinct, model Olsberg) with a wide range of different abutments.

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Fig 7-9c Medical Instinct provisional implant inserted very close to the grafted bone in the left mandible.

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Fig 7-9d Similar situation in the right mandible.

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Fig 7-9e Extreme bone atrophy in the right maxilla.

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Fig 7-9f Insertion of the two temporary implants very close to the grafted bone.

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Fig 7-9g Similar bone atrophy in the right maxilla.

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Fig 7-9h Provisional implants and bone grafting in the right maxilla.

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Fig 7-9i Postoperative radiograph documenting the grafted bone as well as the provisional implants with the different abutments.

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Fig 7-9j Clinical appearance in the maxilla 3 weeks postoperatively.

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Fig 7-9k Similar situation in the mandible.

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Fig 7-9l Temporary restorations.

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Fig 7-9m Clinical appearance with good lip support.

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Fig 7-9n Clinical situation showing the regeneration of the grafted bone near the provisional implant that allows for the insertion of the definitive implant in good conditions.

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Fig 7-9o Similar situation in the left maxilla.

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Fig 7-9p Control radiograph after the insertion of all the remaining implants in the grafted areas.

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Fig 7-9q The temporary implants are removed on the day of the insertion of the definitive restoration. In this case, the maxilla is restored with a bar-retained prosthesis.

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Fig 7-9r The mandible is restored with a screw-retained fixed bridge.

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Fig 7-9s Clinical appearance after the definitive restoration.

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Fig 7-9t The lips are well supported by the restoration, offering a satisfactory esthetic result.

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Fig 7-9u Control radiograph after the definitive oral rehabilitation. One temporary implant was broken during the removal procedure. The fractured part is left in the chin area.

In edentulous patients with severe bone atrophy, the interim implants are inserted during the main surgery, together with the bone grafting procedure. After exposure of the bone, the interim implants are placed into the locally atrophied bone with a high torque. After the insertion of all the interim implants, the bone grafting procedure is performed with screw fixation of the bone blocks in the adequate position. Perforations of the vestibular flap are carried out to stabilize the flap over the grafted area through the abutment of the provisional implants (Fig 7-10a to f). In the mandible, the augmentation or implant procedure is carried out in combination with a vestibular incision based on Kazanjian’s method.13 Also in this situation, the flap is perforated, allowing stabilization through the temporary implants.

An impression of the interim implants is performed at the end of the surgery. One day later, the maxillomandibular relationship is recorded and the esthetic try-in carried out. As a rule, the fixed temporary reconstruction is cemented or screw-retained onto the interim implants 2 to 3 days postoperatively.

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Fig 7-10a Extensive bone grafting close to provisional implants in the maxilla.

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Fig 7-10b Small perforation of the flap close to the abutment.

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Fig 7-10c The flap is adapted on the abutment through the perforations.

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Fig 7-10d The abutments of the temporary implants reduce the tension on the sutures.

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Fig 7-10e Temporary restoration in place.

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Jan 3, 2022 | Posted by in Implantology | Comments Off on Complex implant-supported rehabilitation from the temporary to the definitive restoration
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