Symphyseal Bone Cylinders Tapping With the Dental Implant Into Insufficiency Bone Situated Esthetic Area at One-Stage Surgery: A Case Report and the Description of the New Technique

Long-term success for osteointegrated implants depends on the presence of adequate bone volume, quantity, and quality of the edentulous site. However, an insufficient amount of bone volume may result from trauma, tooth extraction, or infectious diseases such as periodontitis. Alveolar ridge morphology is particularly important in performing esthetic prosthetic rehabilitation and implant placement in the anterior maxilla.1,2 

A number of different techniques have been described to augment the deficient alveolar ridges and to allow dental implant placement either in a simultaneous or consecutive approach. Several techniques for this procedure may be considered, such as guided bone regeneration, bone block grafting, and ridge splitting for bone expansion.3–6 Ridge dimensions affect implant length and width. Moreover, a large interarch space produces an unfavorable crown-to-root ratio in the prosthetic restoration.7 

A classification of alveolar ridge defects has been described to standardize communication among clinicians in the selection and sequencing of reconstructive procedures designed to correct different types of defects.8 Bone augmentation procedures are routinely required before dental implant placement. Thus, the bone augmentation technique employed to reconstruct these ridge defects depends on the horizontal and vertical extent of the defect.

Autogenous bone grafts have been used in alveolar ridge augmentation for many years and have long been considered the gold standard for jaw reconstruction.9,10 However, in recent years, autogenous stem cells may become a new platinum standard.11 Autogenous grafts are harvested from intraoral sites such as the mandibular symphysis, ramus, or maxillary tuberosity, and extraoral sites such as the iliac crests, ribs, cranium, and tibial metaphyses. Extraoral sites are used when significant amounts of bone are required to reconstruct larger deficiencies.12,13 Autogenous bone graft harvested from extraoral sites is often associated with complications and morbidity of the donor site and requires hospitalization and mostly general anesthesia. Block bone grafts harvested from the symphysis can be used for predictable bone augmentation up to 6 mm in horizontal and vertical dimensions.14 In addition, the intraoral grafts derived from intramembranous bone have less resorption than the grafts derived from endochondral bones like the iliac crest, fibula, and tibia.15 

The aim of the present case report is to describe a technique and to evaluate the success of extensive bone reconstruction of atrophic maxillary alveolar ridges utilizing intraoral cylinder bone grafts and simultaneous dental implant placement.

A 61-year-old white male patient suffering from the mobility of maxillary incisor tooth number 9 was referred to the Department of Oral and Maxillofacial Surgery Clinic at the University of Kirikkale Faculty of Dentistry. In the clinical examination, tooth number 9 showed lateral and vertical mobility. Initial radiographic examination revealed advanced bone loss at the number 9 site (Figure 1). A treatment plan including the extraction of the tooth and immediate implant placement was developed and accepted by the patient.

Tooth number 9 was extracted, and a combination of vertical and horizontal ridge deficiency was observed at the extraction site. Placement of the dental implant directly to the extraction site would lead to apically positioned abutment-crown junction and would have resulted in an extremely unfavorable crown-to-root ratio and to an unesthetic restoration. Therefore, it was decided to augment the ridge defect using mandibular symphyseal bone cylinder graft and simultaneous placement of the dental implant.

The procedure was performed under local anesthesia (articaine hydrochloride 4% with epinephrine 1∶100 000). A full-thickness flap with vertical releasing incisions was reflected. Horizontal and vertical ridge deficiency was evident (Figure 2). After the bony defect was evaluated and measured, the symphysis was exposed by a sulcular incision between the mandibular canine teeth. A trephine burr with an internal diameter of 10 mm (KLS Martin and Mondeal Medical Systems, Tuttlingen, Germany) was used to remove bone cylinder, in the length of 8 mm (Figure 3). The osteotomy was performed at least 5 mm apical to the mandibular incisors under copious irrigation. The bone cylinder was then tapped into the extraction socket, and an implant was placed into the bone cylinder (3.7 mm wide and 16 mm long; Implant Direct LLC, Calif) (Figure 4). Four months later, healing cap surgery was performed after panoramic examination (Figures 5 and 6). One week later, a definitive crown was successfully placed (Figure 7). After restoration, the implant was followed for 1 year without any clinical and radiographic problems or complications.

The vertical alveolar bone defects can be corrected prior to or simultaneous with implant placement. The major advantage of a one-stage procedure, in addition to the lower number of surgical interventions required and reduced overall healing time, is that the bone graft stabilization is provided with implants. Generally, the single-stage approach has proven to be safe and effective.16 An important disadvantage of the combined graft-implant procedure is that the graft failure also implies implant failure. Furthermore, graft failure may result in an implant that osteointegrated in its apical zone but may not be supported by bone in its coronal zone.

In the presented case of a one-stage approach, the implant and vertical ridge augmentation were completed simultaneously. The primer implant fixation and stabilization was found to be successful. Complete or partial graft failure was not experienced.

Lekholm et al17 reported that a two-stage approach provides higher success rates than a one-stage approach. However, if complete initial stability and ideal implant position is accomplished, a one-stage method can be as successful as a two-stage procedure. In our case, initial implant stability was provided.

The placement of implants into grafted bone is today a well-established treatment. The use of autogenous bone is considered to be the gold standard.18 Autogenous intramembranous bone graft provides several advantages, such as minimal resorption and high concentration of bone morphogenetic proteins and growth factors.19 The mandibular symphysis, as a donor site for the ridge augmentation, provides a relatively small quantity of bone, but offers easier access, low morbidity, minimal graft resorption, and the avoidance of an undesirable cutaneous scar.20,21 In addition, the bone graft could be harvested in the form of a bone cylinder, which simplifies stabilization in the recipient sites.

Simion et al16 reported that the characteristics of a regenerated bone depend more upon the bone quality of the recipient site than the quality of the grafted bone.

Kaufman and Wang3 used bone cores, but preferred a two-stage approach over a one-stage approach. However, we preferred a one-stage approach in order to shorten the treatment duration.

Typically, two-point stabilization of grafts has been shown to offer the best chance for graft success. In our technique, autogenous bone cylinder was shaped to fit the size of the bony defect, and adapted to the defect. The first point for stabilization for this technique was obtained by tapping the graft into the recipient site, which was suitable for the tapping. The second point for stabilization was secured by using the implant. Furthermore, two-point stabilization was achieved. Stabilization of the bone cylinder autogenous graft is important because graft mobility can result in nonunion and resorption. Tension-free primary closure of the recipient site is also momentous for successful results as are other bone grafting methods.

The trephine technique is useful in alveolar bone grafting because it provides structural bone grafts and cancellous bone. Harvesting of bone from symphysis using a trephine appears to be safe and results in minimal morbidity for many maxillofacial procedures. The authors consider the ascending ramus and maxillary tuberosity to be suitable donor sites for this technique for getting cylinder block grafts. However, further cases are needed to explain the advantages and disadvantages of different donor sites on the efficiency of this technique. In several techniques, fixation of the bone block requires usage of screw or plate fixation. But, in this technique, tapping the bone block with the dental implant into the fresh extraction socket provides the fixation without any screw or plate. This helps to decrease the operation time, cost of the operation, and handling complications due to screw or plate fixation. As a result, this technique provides a more practical approach on bone grafting and dental implant surgery.

There are some prerequisites that need to be fulfilled when our technique is considered for replacing single maxillary teeth in an esthetic zone. First, establishing good primary stability must be the major concern. This can only be granted when long implants are used, crossing the apical portion of the healthy bone. Thus, sufficient bone volume in this area is an important prerequisite. Second, immediate provisionalization should not be performed in cases of buccal bone defects extending to the buccal crest. Third, in our technique, screw-type tapered implants must be used so that it is easier to achieve primary stability.

In the described one-stage technique, the bone cylinders are stabilized by tapping and implanting into the recipient site; this allowed a decrease of the chair-side time. Moreover, harvesting of bone from the symphysis using a trephine burr is simpler and more conservative than the conventional osteotomy technique. Vertical alveolar ridge augmentation using autogenous bone cylinder with simultaneous implant placement can effectively increase alveolar ridge height and allow for an acceptable level of osseointegration. We recommend at least 5 mm of healthy bone beyond the apex and a bony length of 10 mm or greater for stability when placing implants. Our technique seems appealing for the clinician. This technique provides significant advantages, including fewer surgical procedures and shorter treatment time. Further investigations are necessary to determine the clinical applicability and long-term results of this new technique.