The alveolar process is a delicate anatomic structure crucial in oral rehabilitation involving dental implants. When teeth are present, mechanical loading is detected by osteocytes, which release signaling molecules to promote osteoblast activity, maintaining bone turnover to support tooth function. However, after tooth loss, the absence of a tooth root to transfer mechanical stimulation leads to decreased osteoblastic activity and activation of osteoclasts, resulting in bone resorption. Consequently, the alveolar ridge undergoes significant dimensional changes, ^, with reductions of up to 50% in height and width within 6 to 12 months after extraction.

As a consequence, when edentulous patients require replacement with dental implants, these deficiencies can lead to complex clinical situations for implant placement and treatment planning. These cases often necessitate bone augmentation procedures, either staged or performed simultaneously with implant placement. Although dental implants serve as an ideal tooth replacement that can also provide this mechanical stimulation, the damage they are capable of causing if they fail because of peri-implant diseases or need to be removed for other reasons such as unfavorable aesthetics can be devastating. Such situations can result in significant defects that require advanced augmentation procedures. Given the increasing age of the population, the prolonged retention of periodontal involvement, and the high prevalence of peri-implant diseases, these defects are becoming more common in current implantology practices. Furthermore, even in cases without major tissue loss, placing implants in their prosthetically guided position often necessitates performing guided bone regeneration (GBR) to create the critical buccal bone thickness to ensure stable, long-term peri-implant bone support.

Although bone augmentation procedures are highly technique sensitive, systematic reviews have shown that, when performed correctly, it can yield an average of 4.28 mm in horizontal as well as 4.16 mm in vertical bone regeneration. However, achieving predictable vertical bone regeneration poses unique challenges compared with horizontal augmentation (Urban and colleagues 2019). For this purpose, several techniques have been proposed. The most common involves using autologous bone grafts, originally described as the gold standard for vertical defects. Variations on this approach include the Khoury technique, the wafer technique, and the split bone block technique (SBBT). ^, However, current improved biomaterials and membranes have allowed slightly more conservative approaches like GBR to also obtain good results augmenting bone in a vertical direction. Regardless of the used surgical technique, these cases come with a heightened degree of technique sensitivity and more complex surgical approaches, both of which add to an increased likelihood of complications, which have a reported average of 20%, as well as patient morbidity and need for repeat intervention in up to 25% of cases.

In addition to these notable challenges associated with vertical augmentation, the procedure often resulted in greater morbidity because of the frequent need for a second surgical site to harvest autologous bone. In contrast to horizontal augmentation, which typically occurs within or adjacent to bony contours with a more robust vascular supply, vertical augmentation typically extends beyond the alveolar crest and lacks the benefit of a vascularized bony housing. As a result, vertical grafts must rely on a more limited blood supply. To address this challenge, the use of autogenous bone is frequently recommended. Autogenous bone contains a rich supply of osteogenic cells and growth factors and facilitates blood vessel formation. Moreover, because of the lack of osseous wall containment in most vertical defects, reinforcing the graft with autogenous bone plates offers superior structural stability, maintaining space for new bone development while promoting reliable and predictable regeneration. If the GBR approach is used, titanium reinforced nonresorbable membranes are commonly used to provide increased graft stability and containment during healing. ^,

Because of the larger volume of augmentation in vertical grafting, these cases also require a significant amount of soft tissue advancement to provide a primary closure and tension-free healing in a closed environment. In advanced cases, this can lead to significant repositioning of the mucogingival junction and subsequent obliteration of the vestibule, which often necessitates further soft tissue grafting in a another intervention. From the patient’s perspective, these additional surgeries add, once again, significant morbidity to the overall treatment, and increase the total treatment time, both of which have impacts on quality of life.

Although the added complexities of vertical augmentation may seem daunting, successfully regenerating the vertical dimensions of the alveolar crest can allow for ideal implant positioning, limiting prosthetic complications due to large crown height spaces, which can also allow patients to have more favorable oral hygiene and reduce possible biological and biomechanical complications. ^,

In a specific subset of patients, this may even reduce the overall morbidity of a patient’s treatment plan, as many patients may be on a path to total edentulism if vertical augmentation cannot be achieved. In the case of full arch rehabilitations, a patient is typically planned for an FP3 prosthesis when there has been a history of vertical resorption of the alveolar crest. In these circumstances, the entire remaining arch will often be reduced to the level of the vertical defect. The rationale for this treatment is that vertical augmentation procedures are unpredictable and have a high degree of morbidity. However, the demolition of a patient’s entire alveolar process should not be taken lightly. Especially in the case of younger patients in whom implants will be needed to provide decades of function, this ostecomy may result in a nearly impossible rehabilitation should the implants fail in the future. Thus, being able to manage these severe vertical defects, which are becoming more common in modern-day clinical practice, should be within the abilities of an oral surgeon who performs dental implant rehabilitations.

Thus, the aim of this article was to showcase certain clinical scenarios of severe vertical bone defects and their resolution, in order to enhance further understanding of the complexity that they present, and provide different advance bone grafting techniques to manage them. This hopefully encourages readers to apply insights from these case scenarios in order to improve their clinical practice.