Ridge Split Technique With Immediate Implant PlacementA Case Report

INTRODUCTION

Atrophic ridge which need prosthetic rehabilitation is one of the most common problems faced presently in the field of oral rehabilitation. After the teeth is lost, the resorption of the alveolar ridge occurs in the vertical, transversal, and sagittal planes with the transverse direction being more prominent.¹ Most of the resorption occurs in the first three months after extraction.² In such situations the placement of implant is difficult as it’s necessary to have at least 1.5mm of bone around the implant.³ The lower jaw is seen to be more affected than the upper jaw. The posterior region of the mandible and maxilla show more bone loss and atrophy compared to the anterior region. Therefore when the bucco-lingual width of the bone is less than 6mm, a transversal ridge augmentation is required. Among different techniques which have been incorporated for expanding alveolar ridges with horizontal bone deficiencies, the ridge split technique has emerged as a successful procedure with a 98% to 100% survival rate suceeding the insertion of dental implants.⁴ After being first introduced in the 1970s, this has been in use for horizontal ridge augmentation. The advantage of using the ridge split or ridge expansion technique is that both bone augmentation and implant placement can be done in a single procedure. The elasticity of the bone is exploited in this technique hence a careful evaluation of the ridge (clinicallyand radiographically) is necessary to decide if the traditional bone augmentation or a ridge expansion has to be done. The traditional use of burs or drills causes lamellar fracture and delay in the onset of osteogenesis in the desired site which can be overcome with the micromechanical cutting action of the piezosurgical unit. The captivating properties of piezoelectric surgery is its excellent control during surgery, minimum surgical trauma and rapid healing of the tissues. Thus it’s less invasiveness and simplicity has made it as one of the most sought after procedures for bone expansion and immediate implant placement.^5,6

In this case report we have performed a horizontal ridge augmentation by ridge split technique using a piezosurgical unit and immediate placement of implant.

CASE REPORT

A 36-year-old female came to the outpatient department of periodontology with the chief complaint of missing left back lower tooth which was extracted one year back due to caries.

On intraoral examination, Kennedy's class III edentulous space wrt mandibular left second premolar with Siberts class I ridge deficiency was noticed. The patient was moderately built and nourished with no systemic illness or any deleterious habits. A complete case history was taken following which preoperative procedures including OPG, a cast for ridge mapping, oral prophylaxis and routine blood investigations were done. As the patient was more interested in a less invasive procedure which would avoid the use of a secondary donor site for augmentation, a ridge split procedure was planned, to achieve an adequate ridge width for subsequent implant placement. The complete treatment plan was explained to the patient, and a written consent was obtained.

SURGICAL PROCEDURE

The site of interest was anesthetized using 2% lignocain 1:100,000 epinephrine. Following which a mid-crestal incision was placed which extended into the sulcus of the adjacent teeth. The crevicular incision extended from the first premolar region to the first molar region. A full thickness mucoperiosteal flap was raised.

The first osteotomy was performed using a piezosurgical unit. The corticotomy was carried out at the centre of the occlusal aspect of the ridge and the incision was extended in the in anteroposterior direction for the planned length. Then the vertical osteotemies were carried out in the proximal and distal ends of the crestal incision. The osteotemies extended from the outer cortical bone to the inner cancellous bone. The tips were used in progression from number one to number five to deepen the osteotomies. The tips were used at high power resulting in rapid cutting till the groove on the bone surface become retentive. Then, a greenstick fracture was made using chisel and a ridge split was created carefully. Implant was subsequently placed in the site (3.5mm × 11.5mm). This was followed by placement of bone graft (DM Bone), an alloplast which was placed until the desired separation of the two cortices was reached. Platelet-rich fibrin was then placed over the graft, and the flap was replaced and sutured back. The sutures were removed after 10 days. The patient was recalled after 6 months after which the clinical and radiographical investigations were performed to evaluate the healing and bone gain around the implant. The investigations revealed satisfactory soft tissue healing and bone formation at the site. Then an incision was made around the implant to place the healing cap. Two weeks later the patient was recalled and a final impression was recorded using Polyvinyl siloxane (3M ESPE Soft Putty). Implant-supported porcelain-fused-to-metal crown was cemented a week later.

DISCUSSION

RIDGE SPLIT TECHNIQUE

Osseointegration happens at it best when an implant is completely embedded, with a required minimum amount of bone. In cases when alveolar ridge present, is not optimal enough for an implant to be placed, then adjunctive methods like the usage of bone grafts, GTR and other regenerative techniques are preferred.⁷ But all of these pose a number of drawbacks like being invasive, grafting material might resorb, healing might take a long time as the integration of the regenerative material takes time.⁸ To overcome these drawbacks this less invasive method of splitting the ridge to create more space was introduced.⁹ this technique was introduced about 20 years back with the aim to create “self making space” to allow the graft to be contained in the space created by the surrounding bony wall.¹⁰ The buccal cortical plate which is dislocated by splitting the ridge can be moved in a labial direction and the space created heals in a similar manner to that of an extraction socket. The greatest advantage of this procedure is eliminating the need for a second surgical site.¹¹ this technique of splitting the ridge for expansion for placement of implants has been implemented in various studies and cases which required bone augmentation in atrophic ridges and has shown a 98% to 100% survival rate succeeding the insertion of dental implants.4,9-14

PIEZOSURGICAL UNIT.

Piezoelectric bone surgery was introduced and developed to overcome the limitations of conventional bone cutting instruments. It’s unique properties like microprecision, selective cutting, maximum visibility and excellent healing favours the release of bone morphogenetic proteins causing early onset of osteogenesis at the sites were they are used. This has been used for crown lengthening, tooth extraction, sinus lift procedures, ridge expansion, bone harvesting etc. for splitting the ridge a horizontal osteotomy can be created using its precise cutting property. In areas of dense bone vertical cuts can also be placed for a smoother ridge expansion.^5,6 Attemting to create a space between the buccal and lingual cortical plates with traditional drills increases the chance of fracture, especially when the buccal cortical plate is weaker and inelastic which can be overcome with this technique. Piezoelectric surgery has thus greatly simplified the ridge splitting and expansion technique. Since the introduction of this technique, this has been used widely for ridge split and subsequent implant placement.^5,6,11

BONE GRAFT AND PRF

The placement of bone graft along with a membrane (platelet rich fibrin) promotes further bone regeneration due to the property of cell occlusiveness and also the release of growth factors from the membrane.¹⁵ PRF contains autologous leukocyte platelet rich fibrin which has a tetra molecular structure which contains stem cells, cytokines and platelets. This acts as a scaffold which favours microvascularization and also guides the epithelial cells into its surface.¹⁶

CONCLUSION

The incorporation of piezosurgical unit for ridge split technique in obtaining appropriate positioning of implants with horizontal bone augmentation is an effectual method in treating horizontal bone defects and placement of implants in sound bone. With its many advantages like minimum surgical trauma, precision in the depth of the cut and rapid healing of the tissues makes it an effective and efficient procedure to be used in all regenerative procedures in a safe and comfortable manner. Thus in this case we have incorporated a less invasive and a safe method of ridge split with the use of piezosurgery and regenerative methods in a single sitting approach with subsequent placement of implant.