Bone and Soft Tissue Augmentation in Implantology

In addition to a pressure point in the area of the masticatory muscles, deviations from the mouth opening pathway as well as clicking and rubbing in the region of the TMJs appear as signs of functional disorders. Especially in partially edentulous jaws, it is important to evaluate the vertical dimension preoperatively. Suspected atrophy, which is compensated for by augmentation in the horizontal and vertical dimensions, can result in a prosthetic complication with a deficient prosthetic restoration or one that is difficult to perform because there is insufficient vertical dimension after augmentation. Accordingly, it is necessary to assess the elongation of the antagonist teeth and the need for correction in the antagonist jaw in case of loss of the vertical dimension before the surgical procedures ( Fig 2-9a).

Especially in patients with a generalized aplasia, there is a tendency for a deep bite and the retention of the primary teeth. As a result, the alveolar process does not develop according to age. In the treatment plan of such cases, a bite raising should be considered in addition to the reconstruction of the alveolar ridge by grafting procedures ( Fig 2-9bto j).

Soft tissue quality and quantity are important criteria for a successful bone grafting procedure. A thin soft tissue biotype as well as scar tissue represent a high risk of tissue necrosis, with exposure of the grafted bone. Especially after several surgeries and in cases of previous surgical procedure failures, bad vascularized scar tissue occurs on the soft tissue. Particularly, in infection cases with augmentation procedures using biomaterials, the xenogenic bone substitute material remains in the connective tissue, making a flap preparation very difficult and significantly reducing the vascularity of the tissue ( Fig 2-10ato c). Therefore, in the case of severe scars, it is advisable to improve the quality of the soft tissue through the removal of all biomaterial from the soft tissue and subsequent grafting of the palatal connective tissue at least 2 months prior to the hard tissue augmentation. The use of a tunneling technique in case of vertical bone augmentation will reduce the risk of tissue necrosis and bone exposure (see Chapter 3 on the soft tissue).

Fig 2-9aGeneralized oligodontia with poorly developed alveolar process and loss of vertical dimension.

Fig 2-9bPersistent primary teeth with multiple aplasia.

Fig 2-9cPlan to increase the lost vertical dimension.

Fig 2-9dElevation of the bite by vacuum-formed stents in the shape of the definitive fixed prosthesis.

Fig 2-9ePreoperative panoramic radiograph.

Fig 2-9fStrong atrophy of the mandible after extraction of the primary teeth.

Fig 2-9gClinical situation after bone augmentation with a bone graft harvested from the chin area.

Fig 2-9hExtension plastic in the maxillary right jaw with a bone block from the chin area.

Fig 2-9iClinical situation 13 years after implant prosthetic restoration.

Fig 2-9jPanoramic radiograph 13 years postoperatively.

The soft tissue situation may also be limited by increased nicotine consumption. Also, systemic diseases that affect the blood circulation such as unadjusted diabetes mellitus with HbA1c values above 8% can lead to wound healing disturbances. 80Therefore, it is important to evaluate the structure of the soft tissue in the planned surgical site in order to take into consideration the number and course of any previous surgery or internal medical factors. Inflammatory symptoms should be treated as part of a systematic periodontal treatment prior to bone augmentation.

In the case of oral mucosal changes, these should first be clarified, as a leukoplakia must be assessed as precancerous. 95A soft tissue change, which is judged inconspicuous during tooth extraction, may recur after superficial removal, as it may be an epulis gigantocellularis. 74

Pretreatment in the field of cariology, endodontics, and periodontics should be provided to the extent that the medium-term maintenance of the natural abutment is guaranteed. Where the abutment teeth have a limited prognosis, what must be carefully considered is whether the remaining teeth should be used for anchoring the prosthesis in the interim phase. Alternatively, a corresponding increase in patient comfort can be achieved by an immediate restoration on temporary or permanent implants.

If the cause of tooth loss is periodontal disease, the simple hygienic ability of a prosthetic superstructure should insure against it to some extent in the future, as it has been proven that a higher risk of peri-implantitis is present in edentulous patients. 84

In the case of a deep bite, a possible vertical reconstruction should be evaluated by functional bite plane treatment before starting the grafting procedures. This can prevent further complications during the prosthetic restoration. After determination of the ideal vertical height, the amount of vertical reconstruction should follow in such a way as to avoid a limited maxillomandibular relationship. A simulation of the prosthetic result using a wax-up may assist decision making, especially after traumatic looseness of the teeth and bone, which creates an open bite situation that complicates the finding of an adequate solution ( Fig 2-11ato c).

Fig 2-10aLarge bone defect with severe soft tissue scarring after several augmentation experiments with xenogenic material.