Autogenous Bony Halo for Ridge Augmentation and Simultaneous Implant Placement

Introduction

The alveolar ridge resorbs quickly within six months after dental extraction. Numerous factors, including periodontal disease, any pathology in the periapical area, trauma, or the patient's general health, can cause the resorption of the alveolar ridge even before tooth loss.¹ These reasons can result in deformities in the alveolar ridge thereby posing a challenge to the longterm function and aesthetic success of management with dental implants.²

The amount of alveolar bone present at the edentulous area has a significant impact on how successfully a dental implant is placed. A good amount of alveolar bone is required for the placement of an implant securely and to produce good aesthetic results in the long run.³ The final implant restoration should have surrounding tissues that are harmonious with the dentition around it.⁴ Even though the quality of the surrounding tissue before the implant surgery is a huge challenge, utmost importance must be given to evaluating how precisely the surgical techniques are carried out.⁵

A variety of methods have been discussed for the augmentation of defective sockets to place implants in either a simultaneous or a subsequent manner. Localized horizontal ridge augmentation using titanium mesh and onlay bone grafting, guided bone regeneration, and socket preservation are some of the techniques.⁶

Studies on surgical methods for horizontal bone augmentation have shown good levels of predictability, minimal rates of complications, and implant success rates of 97%–100%.⁷ Vertical ridge augmentation, on the other hand, is a biologically demanding procedure that, has been linked to greater complication rates and lesser predictable outcomes, as a result of its high sensitivity.⁸ Additionally, these augmentation techniques frequently need a phased approach, that is, guided bone regeneration, alveolar distraction osteogenesis, or repair using bone blocks, which have significant morbidity and extended treatment times.⁹ The bone ring procedure was proposed to minimize these limitations. It is a onestage procedure for ridge augmentation which utilizes either an autogenous or an allogenic cortico-cancellous bone block graft that is stabilized with the subsequent placement of the dental implant.¹⁰

The osteoinductive, osteoconductive, and volume enhancement features of bone grafts make them an appropriate choice for the management of threedimensional (3D) alveolar bone deformities.¹¹ The application of the bone ring approach for implant site augmentation and simultaneous implant insertion is described in the current case report.

Case Presentation

A 45–year–old male reported to the department of Periodontology with a missing lower left premolar. The patient was systematically healthy and did not report any deleterious habits. When radiographically examined, both vertical and horizontal bone loss was seen. (Figure 1).

Diagnostic casts were mounted to visualize the treatment plan (Figure 2). The bone mapping was done. The executed treatment plan was implant placement with simultaneous ring bone graft augmentation from symphysis. The procedure was explained to the patient and informed consent was obtained before the procedure.

Diagnostic casts were mounted to visualize the treatment plan (Figure 2). The bone mapping was done. The executed treatment plan was implant placement with simultaneous ring bone graft augmentation from symphysis. The procedure was explained to the patient and informed consent was obtained before the procedure.

Horizontal incisions were made in the edentulous area. The implant site was prepared using standard pilot drills and subsequent drills. (Figure 5). The bony halo in the form of a bone ring was harvested. It was then secured in the socket (Figure 6 and 7). The primary stability of the bone ring was achieved and was increased by tapping the implants through the "bone ring". (Figure 8) Finally, the covering screw was secured. (Figure 9) Sutures were used for the primary closure of the wound in a tensionfree manner (Figure 10).

The patient was then advised to place cold packs on the chin and cheek area for 20 minutes every hour for the first six hours following the surgery. Second day onwards, the patient was instructed to rinse his mouth with warm saline solution three times per day for the first week postoperatively. The patient was asked to take only a soft diet for the first 48 hours. Antibiotics, analgesics, and anti-inflammatory medications were prescribed post-surgery. On the follow-up visits, the healing of the wound was evaluated at the donor and recipient sites. No clinical complications occurred during the one-month follow-up (Figure 11).

Discussion

Dental implants have been successfully used to restore lost teeth, and their predictability depends on the success of osteointegration throughout the healing process.¹² In daily practice, 3D ridge deficiencies in the edentulous areas have been repaired with autogenous block bone grafts. Autogenous block bone grafts can be corticocancellous or free cancellous, and they can be obtained either from intraoral or extraoral donor sites. There are numerous growth factors and cells present in autogenous grafts which exhibit osteoinductive, osteoconductive, and osteogenic actions.¹¹ One of the best ways to increase the inadequate bone volume in the edentulous area is by the use of an intraoral autogenous block graft which is considered the gold standard.¹³

The “bone ring technique” was first proposed by Giesenhagen, and allows theplacement of an implant and 3D augmentation simultaneously in a single surgery. When correcting major abnormalities, the bone ring approach has a substantial advantage over traditional bone grafting in terms of shortening the overall treatment period.¹⁴

In the present report, a one-stage surgery involving the bone ring approach was employed to augment the implant site while simultaneously placing an implant. This approach has several benefits, including the potential to increase the implant’s stability at its crestal region and a 3D augmentation of the natural alveolar ridge. Additionally, the socket gap implant interface is removed. The bony halo, whichis shaped to fit snugly inside the socket walls is screwed to the implants to offer further support. In the aesthetic zone, the use of “bone rings” for augmentation improves the contour of the soft tissues and aids in resisting soft tissue contraction.¹⁵

In comparison to other intraoral sites, the mandibular symphyseal bone includes more cancellous bone, offering more osteoprogenitor cells. For intraoral augmentation up to 6mm in both the horizontal and vertical dimensions, mandibular symphyseal bone has been used universally. Additionally, these intraoral grafts obtained from intramembranous bone resorb slowly when compared to grafts made from endochondral bones like the iliac crest, fibula, and tibia.¹⁶

Greenberg JA et al. carried out a study on 14 patients and before the implant surgery, they utilized an autogenous block graft for the reconstruction of defective bone in the maxillary anterior region. They opted for a two-stage surgery for placement of the implant after successful augmentation.¹⁷ Whereas in our case, we preferred a one-stage procedure and successfully performed augmentation. Additionally, it enabled us to complete the procedure faster without doing a second surgery.

It is crucial to consider the graft’s thickness and the distance to the mandibular anterior teeth while harvesting the graft from the symphysis region. If a huge amount of graft is harvested, it can result in fracture or contour distortion of the mentum. Therefore, only a certain amount of graft should be harvested. To prevent damage to the roots of anterior teeth, the donor site limits must be set at a distance of 5mm from the roots.¹¹ In this case, we used a trephine bur to place the ring block graft limits at least 5mm away from the teeth.

The precise dimensions of the socket and the implant to be used were used to calculate the dimensions of the graft ring. The ring’s inner diameter and outer diameter should both match the dimensions of the implant and the socket, respectively. Additionally, with the help of a trephine bur, the recipient site was prepared so that the graft would fit snugly. This helped to achieve the complete stability of the implanted bone ring, which was necessary for quick healing and reduced resorption of the graft.¹⁸ However, the healing after the use of the bone ring graft is not well explained in the literature.

In this case, the vertical ridge augmentation and implant placement were done simultaneously. The major benefit apart from fewer surgical procedures and decreased healing time is the bone graft stability obtained by implants. In general, this single-stage method is reliable and safe.

Conclusion

The time needed for treatment of implants placed in severely damaged sockets can be reduced greatly with the help of the bone ring augmentation method. Predictability is primarily ensured by well-planned surgical procedures and well-executed treatment plans. The success of this procedure is greatly influenced by the patient selection process and the initial stability of the implant-bone ring complex. Additional studies on large populations and greater follow-up durations are required before considering the bone ring augmentation approach as a reliable surgical procedure.

Conflict of interest

None