11

Decision Making According to Defect Stage

In the age of artificial intelligence, evidence-based medicine, and guidelines, the decision in favor of a certain therapy path should be easy, perhaps even possible by machine. In fact, however, the decision is also becoming more difficult. The wealth of information and multiple influencing patient-related factors (local, systemic) have to be reconciled. The enormously variable genetics and epigenetics of patients are already biologically opposed to all schemes, so that individualized medicine represents the countermovement to automated decision making. In the following chapters, an attempt will be made to structure therapy decision making according to the criteria of defect stage and indication. The term decision making is used synonymously with the medical term differential indication.

11.1 Defect-Oriented Concept for the Differential Indication of Augmentation Procedures

Clinically, the physician’s indication should always be based on the patient and his or her individual clinical condition. The physician’s performance is not based on techniques, materials, and methods. These were presented in the previous section and are now to be classified clinically in terms of their value. With regard to augmentations, this means starting from the defect stage. In this chapter, a defect-oriented concept for the differential indication of bone augmentations will be presented and further elaborated with reference to the initial publication in the ITI Treatment Guide 7.¹ This concept is initially intended to propose universal solutions for all jaw regions. The following clinical chapters then present the specific indications that require deviations from this concept, for example, large graft volumes in the edentulous jaw that can not be managed with the intraorally harvested external oblique ridge block graft.

Classification system

The classification system of the concept presented here is the resorption stage of the jaw, based on the quarter classification (Fig 11-1; see chapter 1). This treatment scheme applies to single-tooth gaps, free-end situations, and in principle also to edentulous jaws, but with the limitation of bone graft volumes. Also, in the edentulous jaw, it is much easier to compensate for a vertical deficit prosthetically than with augmentation because the adjacent teeth are missing as a reference.

Fig 11-1 Decision making for an augmentation procedure depending on the defect stage. GBR, guided bone regeneration.

Main technique and alternatives

For each stage of the defect, one procedure is suggested as the main technique, along with an alternative. All four stages occupy equal space in the table in Figure 11-1. In practice, however, the vast majority of cases are in stage 1/4 and can therefore be treated satisfactorily with the least complex technique.

Outpatient feasibility

All augmentation procedures presented here can in principle be performed on healthy patients on an outpatient basis under local anesthesia or, if necessary, with sedation. This fact makes the concept suitable for the private practice and for the patient means that bone augmentation remains affordable and does not require inpatient treatment.

Healing time

For all procedures proposed here, the healing period is 4 months, either until implant uncovering or until implant placement for two-stage procedures.

11.2 Defect Stage 1/4

The 1/4 defect is the earliest stage of resorption of the alveolus, when a large coronal portion of the buccal wall is missing a few weeks after tooth extraction. Guided bone regeneration (GBR) cases usually make up the bulk of patients in practice, because most patients and their dentists take care of the tooth replacement issue soon after a tooth extraction. In stage 1/4, there is still enough bone basally for primary implant stability (Fig 11-2). GBR functions particularly reliably in contained defects of single-tooth gaps within the envelope with preserved adjacent periodontium and bone walls. The more elongated the defect, the further outside the envelope the implant position is located, and the fewer adjacent teeth are present, the more likely the bone block is to be considered as an alternative to GBR. This has a higher regenerative potency and more inherent stability and buildup effect than GBR. In addition, the block eliminates the overcontouring of the particulate graft techniques, and the method is more precise than GBR. Because in stage 1/4 the implants are usually placed in one stage, this corresponds to “advanced” in the SAC (straightforward, advanced, complex) classification.

Fig 11-2 GBR technique for a 1/4 defect. a. Initial situation after implant placement and perforation of the cortical bone. b. A Bio-Gide membrane (Geistlich) is cut into a tongue shape. c. The tongue of the membrane is placed under the lingual flap margin and thus fixed in place. d. Sterile venous blood is added to the bone substitute material (Bio-Oss, Geistlich). e. The sterile blood should be drawn into all cavities of the bone substitute material so that they do not attract contaminated saliva when applied in the mouth. f. During all bone work (cortical perforation, implant osteotomy), the filter (Schlumbohm) is inserted briefly into the aspirator in each case to collect the chips.

Fig 11-2 GBR technique for a 1/4 defect. g. The chips are removed from the filter screen. h. So far, the blood has not coagulated with the bone substitute material due to lack of tissue thrombokinase. For this purpose, the filter bone is now mixed in at a ratio of 25% to 75%. i. After mixing in the bone, the blood coagulates, and easily manageable bone grafts are formed at the appropriate thickness. j. The pieces can be placed in the defect. k. The bone grafting material can be modeled in the defect. l. The still dry collagen membrane is folded over the bone graft.

Fig 11-2 GBR technique for a 1/4 defect. m. Moistening the membrane with a few drops of saline solution causes it to soften and adhere relatively firmly to the graft like blotting paper. The length of the soft tissue flap is checked with the single hook. n. A section of the membrane is placed as a double layer. o. The flap is mobilized by periosteal release incisions with the aid of the single hook and the scalpel. p. Due to the incision being made in the center of the attached gingiva, only a few sutures are required at a relatively large distance to close the wound tightly. This ensures blood supply to the flap margin. q. Panoramic radiograph showing stable augmentation in the mandibular right first molar region at the time of implant exposure. r. Stable clinical situation after prosthetic restoration.

Fig 11-3 Single-stage bone block graft in a 2/4 defect. a. Baseline panoramic radiograph. b. Baseline following coronectomy of the premolars, showing horizontal atrophy.

11.3 Defect Stage 2/4

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