Immediate Dentoalveolar Restoration in Compromised Sockets: Technique and Bone Biology Immediate Dentoalveolar Restoration in Compromised Sockets: Technique and Bone Biology

The aim of this chapter is to describe a one-stage technique called immediate dento- alveolar restoration (IDR) which uses autogenous bone graft harvested from maxillary tuberosity in order to restore bone defects in compromised alveolar sockets and also to achieve soft tissue stability along the years. The IDR is a flapless surgical and prosthetic technique established to broaden indications for immediate loading on individual teeth. In this way, tissue loss with varied extensions are reconstructed in the same surgical session as implant placement and provisional crown installation, reducing the number of interventions and retaining esthetic predictability. Successful esthetic and functional outcomes and reestablishment of the alveolar process after bone reconstruction were observed during the follow-up period. The predictable results and soft tissue stability can be achieved following the IDR protocol.


Introduction
Esthetic rehabilitation in cases of tissue loss in anterior areas represents a major challenge in dentistry with respect to the treatment planning when the choice of therapeutic options is aimed at maintaining the tissue long-term [1]. The developed surgical recommendations require longterm treatment with possible undesirable complications in the tissue architecture [2][3][4][5][6].
These cases can also be successfully treated using immediate dentoalveolar restoration (IDR), a previously described one-stage technique [1,7] that allows dental extraction, implantation, and provisionalization to occur during the same procedure as the flapless bone reconstruction using a corticocancellous bone graft harvested from the maxillary tuberosity [8][9][10][11]. The IDR technique, in addition to having lower overall cost and treatment time, has been shown clinically and tomographically to be effective regarding bone and soft tissue stability [9].
According to the IDR protocol for total loss of the buccal bone wall, the corticocancellous is shaped to the defect size and inserted between the implant and the remaining buccal soft tissue without opening the flap [1,7,9,11]. Then, particulate bone is compacted until it completely fills the gaps between the main graft and the implant surface [7][8][9]. The provisional restoration is made at the same time. The proper anatomical contour of the prosthetic emergence profile is mandatory to guide the soft tissue healing [9][10][11].
The key factors that may explain the positive results obtained with immediate and flapless implant insertion and provisionalization using autogenous bone grafts in the esthetic zone are as follows: the flapless procedure may preserve the blood supply of the facial lamella, the sole use of autogenous bone without any bone substitutes and without membranes may prevent resorption due to foreign body reactions, and the placement of the implants along with the palatal cortical border of the extraction socket may increase primary stability and avoid any crossing of the bony envelope [12].
The advantages of IDR include the following: the harvest of maxillary tuberosity is easily performed; the malleability of bone fragment allows adequate adaptation to the receptor region; and the corticocancellous acts as a biological membrane, thereby promoting effective bone and gingival healing [13]. Furthermore, the trabecular nature of grafts harvested from the maxillary tuberosity contributes to the increased revascularization capacity and the release of growth factors to the receptor site [13,14]. The immediate provisional restoration contributes to tissue healing acceleration and formatting the ideal gingival prosthetic emergence profile [11,15].
The position of the implant in IDR, as in any other technique, should be considered one of the main reasons to obtain stability of hard and soft tissues. The protocol used for selecting the diameter and position of implants placed in esthetic zones uses the buccopalatal distance from the socket opening as a reference [16]. Regardless of the tooth to be replaced, a gap of approximately 3 mm between the buccal implant surface and the outer buccal bone wall is expected. After gap filling, peri-implant tissue remains stable using this surgical protocol, which has yielded satisfactory as well as predictable esthetic outcomes in a prospective case series [17].
The most challenging stages of the IDR technical application concern the implant primary stability in compromised alveolar sockets to allow immediate provisional fabrication and bone reconstruction in a single procedure [7,9,17]. In this context, using the counterclockwise rotation of site preparation would increase implant stability in favor of its IDR execution. The osseodensification allows bone autograft by compaction throughout the depth of drilling laterally and at the deepest part of the perforation [18,19]. This nonextraction technique utilizes a designed bur that promotes the application of controlled bone plastic deformation due to the rolling and sliding contact of the bur along the inner surface of the osteotomy [20].

Case report
A 63-year-old female presented with the right lateral incisor fractured with abscess, fistula, severe bone loss, and low soft tissue quality ( Figure 1).
The periapical radiograph and cone beam computed tomography (CBCT) images confirmed the loss of the buccal wall in the right lateral incisor ( Figure 2).
The gingival architecture showed a very thin periodontal biotype. Intraoral examination with dental probing confirmed that the buccal bone wall had been lost in the right lateral incisor ( Figure 3).
Considering the esthetic and functional demands, the treatment plan consisted of following the IDR technique using the corticocancellous graft protocol. Antibiotic therapy was prescribed 5 days prior and 7 days after surgery due to the contamination of the affected area. The steps included a minimally invasive dental extraction (Figure 4), curettage and cleaning of the socket, evaluation of the extension of the bone defects ( Figure 5), and site preparation using the osseodensification concept (Densah burs kit, Versah, USA) due to the presence of very soft bone in the anterior area ( Figure 6). Burs were used in a noncutting action in a counterclockwise (CCW) rotation at 1100 rpm to prepare the immediate implant site trajectory. Installation      (Figure 7) achieved primary stability, leaving a gap approximately 3 mm at the buccal aspect, construction of a screwed provisional restoration with an ideal emergence profile (Figure 8), and reconstruction of the socket bone defects using corticocancellous graft harvested from the maxillary tuberosity ( Figure 9) with chisels (IDR chisels kit, Schwert, Germany) were performed to restore the bone defects ( Figure 10). The residual gaps were filled with particulate cancellous bone harvested from the same donor area (Figure 11), maintaining the reconstructed bone wall and the surrounding soft tissue. The graft was placed at a biological distance of 2 mm from the bone graft apically to the gingival margin and 3 mm in thickness ( Figure 12).      The screwed provisional restoration was placed in position immediately and was adjusted out of occlusion ( Figure 13). The immediate periapical radiograph showed the bone entirely reconstructed ( Figure 14). A week after the surgery, the soft tissue had improved healing ( Figure 15).
Three months after the surgery, the soft tissue showed the maintenance of volume and papillae positioning (Figures 16 and 17). The definitive restoration was accomplished after 4 months ( Figure 18).
Clinical evaluation after 2 years showed stability of the soft tissue volume regarding gingival margin and papillae ( Figure 19) and the CBCT image showed the buccal wall completely restored with relevant thickness in the right lateral incisor (Figure 20).

Discussion
Different surgical alternatives for bone augmentation in postextraction compromised sockets have been described. However, some of these techniques require longer periods for rehabilitation and are usually costly [3][4][5][6]. As an alternative, the IDR technique using maxillary tuberosity grafts presents significant gains in esthetic results and in treatment time, recovery of the alveolar bone defect at the same surgical implant installation and immediate provisionalization without opening the flap and keeping the gingival architecture in the same position [8]. As previously described, if the soft tissue and periosteum remains attached to the buccal bone, the bone supply will be maintained, allowing rapid graft revascularization [13,14].
Bone density at the buccal, palatal, and basal cortical maxillary tuberosity is lower, compared to other maxillary and mandibular bones [13,17,21]. Due to the small thickness of its cortical bone, maxillary tuberosity grafts are easily shaped and its cortical structure can act as a biological barrier, stabilizing the soft tissue and the particulate bone graft around the implant [7,9]. The  total porosity and porous volume indicate that the corticocancellous structure can act as a scaffold structure for cellular and vascular growth [10,11,15]. The maxillary tuberosity is a source of osteoprogenitor cells and growth factors [14]. Taken together, the cortical and the cancellous bone from the maxillary tuberosity can be considered as an ideal structure for bone regeneration since it is a natural scaffold filled with osteoblastic cells and growth factors [7,[9][10][11].
The structural and biological characteristics of the graft removed from the tuberosity and its proper manipulation and adaptation to the recipient site can be identified as one of the reasons for the success of the IDR technique, as it has been shown in studies monitoring long-term results [1,14,17].
Osseodensification was utilized in the postextraction site preparation in this case to preserve any remaining apical bone and to produce an intimate osteotomy for the implant. This compaction grafting increased implant primary stability and allowed for the higher insertion torque due to the spring-back phenomenon [18,20].
Histological evidence has demonstrated that the compacted, autologous bone immediately in contact with the implant will not only enhance the primary stability due to the physical interlocking between the bone and the device but also facilitate osseointegration due to osteoblasts nucleating on the instrumented bone near the implant [19]. This enhanced implant stability allowed the author to predictably restore this case immediately postextraction for the IDR procedure.

Conclusions
The IDR allowed dental extraction of the compromised alveolar socket as well as implantation and provisionalization in the same procedure as the flapless bone reconstruction using a corticocancellous bone graft harvested from the maxillary tuberosity.
The clinical case showed adequate implant rehabilitation in the freshly compromised tooth with severe alveolar bone defect and the infected site, which strengthened the clinical outcome of the IDR technique using the osseodensification concept. When properly indicated and performed, the IDR technique exhibits a high success rate.