Introduction

Alveolar ridge deformations occur due to causes such as traumatic tooth extraction, advanced periodontal disease, and abscess formation. They complicate or prevent the placement of an implant in an ideal position and also give rise to aesthetic problems.

The condition, which is characterized by horizontal or vertical defects in the alveolar bone or a combination of defects, is observed more often in the maxilla than the mandible^1–6. Application of bone augmentation in this area prior to prosthetic treatment may provide aesthetic and functional comfort and may enable the placement of implants in appropriate positions^1–6.

Recently, various graft materials and techniques have been used in the reconstruction or augmentation of alveolar ridges that have been severely resorbed^1,2,6. Bone augmentation techniques can be used in extraction socket defect grafting, horizontal ridge augmentation, vertical ridge augmentation, and sinus augmentation^1–6. To maximize the results for each of these applications, various techniques have been applied, including particulate grafting, membrane use, block grafting, and distraction osteogenesis, either alone or combined¹. Furthermore, autogenous bone grafts are thought to be the most successful grafts because of their lower infection rates compared to other graft materials and their osteogenic and osteoinductive properties^1,2,4,6. Autogenous bone grafts may be obtained intraorally, from the maxilla and mandible, or extra-orally, from the iliac or tibia, by osteoplasty and osteotomy methods and applied to the defect site as particles or blocks by the osseous coagulum or bone blend methods^1,6.

The volume and shape of the defect play important roles in selecting the method for alveolar ridge augmentation. In particular, in block bone augmentation for horizontal ridge deformation, the mandibular ramus area represents an ideal donor site because it provides adequate, dense bone with sufficient volume for implant placement and short healing times^2,7. At the same time, because the vestibular depth of this site is adequate, this may facilitate the surgical operation.

In this case report, the clinical results of using a free gingival graft (FGG) and a mono-cortical block bone augmentation, applied before dental implant insertion, in a patient with horizontal ridge deformation and a shallow vestibule, are presented, followed by the results of the prosthetic rehabilitation conducted subsequently.

Case presentation

A 57-year-old Turkish male was referred to the Department of Prosthodontics in Karadeniz Technical University, Faculty of Dentistry, Trabzon, Turkey seeking canine and first premolar extraction due to endodontic–periodontal lesions in the left maxillary anterior region, which lacked lateral teeth beforehand. Dental implant indication was also indicated. This site, which had a shallow vestibule due to heavy inflammation and a horizontal bone defect prior to the implant, was decided to be suitable for a FGG technique and mono-cortical block augmentation afterward. Pre-prosthetic surgical operations were performed in three steps.

Free gingival graft operation

Mono-cortical block bone augmentation

Implant surgery and prosthetic rehabilitation

The implant application was performed 6 months later. The screw in the augmentation site was removed and two subperiosteal implants (Zimmer Dental, Tapered Screw-Vent, 4.1 diameter and 10 mm length), based on the prosthetic planning, were placed at the site (Fig. 2) At the same time, the area surrounding the implant was supported with a bone graft and a collagen membrane (Biomend Extend, Zimmer Dental, USA)(Figs. 3a-c). Prosthetic restorations were performed 6 months following the implant application (Fig. 4). A cantilever design retained on the central incisors was prepared for replacing the lateral incisor and splinted metal-ceramic crowns for implant abutments, replacing maxillary canine and first premolar, were fabricated, clinical controls were made for the occlusion and restorations were cemented with glass-ionomer cement. The patient's functional, psychological, esthetic and phonation problems were solved with these prostheses.

Figure 1

Figure 1. Clinical view just before applying the implant to the left maxillary anterior site and 6 months after the cortical block bone augmentation.

Figure 2

Figure 2. Panoramic radiograph after implant application.

Figure 3. (a, b, c) Supporting the augmentation site with bone graft and membrane following implant application.

Figure 3

Figure 3a

Figure 4

Figure 3b

Figure 5

Figure 3c

Figure 6

Figure 4. Clinical view of prosthetic rehabilitation and free gingival graft applied to the augmentation site.

Discussion

Dental implants are preferred over movable prostheses because they provide partially or totally edentulous patients with the ease of using a fixed prosthesis. Additionally, to be successful in implant applications, the soft and hard tissues should be in a certain degree of harmony, and at the same time, have adequate volume and quality¹. For this purpose, hard and soft tissues are prepared for ideal implant positioning by conducting pre-prosthetic surgical operations, such as graft augmentation and mucogingival surgery^1,2,6,8.

The patient presented in this report had a severe horizontal defect and a shallow vestibular depth, resulting from infection in the maxillary anterior site, which made implant-aided fixed prosthetic treatment impossible. The patient was informed that implant application to the site would be a time-consuming process requiring pre-prosthetic surgical operations; an implant-aided fixed denture was applied later at his request. No complication was seen during the surgical procedures; indeed, a non-problematic and rapid healing process was observed.

The surgical operations in our case were performed in three phases; a FGG was achieved in the first step.

The FGG technique is a periodontal plastic surgical operation used to increase inadequate attached gingival width and to cover exposed root surfaces⁸. Studies have shown that this method is also successful in vestibular deepening^8–10. In this case, the FGG was applied for these purposes as well as to cover the block bone graft completely and to enhance healing. As a result, the implant site was prepared for augmentation by applying the FGG graft.

Mono-cortical block bone augmentation was used following the FGG to obtain bone of sufficient volume and quality that would enable implant positioning at the defect site. In cases with horizontal ridge deformations, exposed sites may occur at the axial surface during implant placement. As a result, dehiscence or fenestration defects may occur, which may then threaten the success of the implant. Additionally, in defects in which horizontal ridge formation is too severe, implant placement may be impossible^1,2,6,11. In such cases, increasing the horizontal dimensions before implant placement is currently the most preferred method^{1–6,10}. In partially or totally edentulous patients, several methods have been used to maintain horizontal ridge augmentation^{1–7,11}. A bone block graft is the preferred method for many types of augmentation procedures because it secures both a source of osteogenic cells and a rigid structure for mechanical support^1,2,5,12,13. Recent studies have shown that block bone grafts from the mandibular ramus site lead to successful bone reconstruction in the maxillary alveolar ridge, and the resorption rate of the ridge is quite low^1,2,5,13. At the same time, while obtaining bone from the donor site, neurological complications due to Nervus Alveolaris Inferior injury may arise, and infection may occur in the donor site^1,2. Recently, a sensory deficit in the lower lip and mental areas of 8.3% of cases of mandibular ramus harvesting was reported compared to 16% for the chin as the donor site². However, the slow revascularization and remodeling processes of mandibular bone blocks suggest waiting at least 4 months after graft healing before implant insertion^2,14,15. In our case, the block bone graft was obtained at a limited level due to the donor site’s close neighbourhood with the Nervus Alveolaris Inferior. While this block bone graft was placed in maxillary canin, where the damage was larger, and the defect site in first premolar site, an augmentation procedure was not applied to the site where the lateral tooth was located since the patient did not want a second donor site to be formed. Therefore prosthetic planning was applied as implant-supported fixed cantilever prosthesis. We detected no necrosis in our case, in which we waited for 6 months after the augmentation before applying the implant. The successful result we obtained may have been due to the operation conditions, the patient’s immuno-inflammatory response, and completion of the revascularization process.

In the final surgical step, that is, implant surgery, the implants were placed in accordance with the prosthetic planning and then the block graft site was supported with a collagen membrane and a bone graft with osteoinductive features. Some researchers use these regenerative materials in the augmentation step^1,4,6. However, these materials can also be used during the implant application to support the bone tissue in the site and the implants^1,4.

In conclusion, we presented a case of an implant-aided prosthetic treatment in which a combination of various techniques and materials were applied, and which satisfactorily met expectations. Advances in oral implantology have enabled successful reconstruction of hard and soft tissue defects, and implant-aided fixed prosthetic rehabilitation can now be maintained. We believe that, in cases that require long-term treatment, as in our current case, multidisciplinary treatment approaches may be the most appropriate option.