Maxillary Ridge Split with Simultaneous Implant Placement – A Case Report

Introduction

A dental implant not only restores teeth but also maintains the form of bone by being in harmonious function with the stomatognathic system. Alveolar bone loss results from the traumatic loss of tooth or extraction leading to a sequential pattern of alveolar bone resorption which is inevitable if left unrestored, leading to the atrophic alveolar ridge. These regions with atrophic ridges need complex bone volume augmentation procedures to receive prosthetically driven implants. Buccal cortical plate undergoes drastic changes after loss of natural tooth or extraction. Approximately 25% bone volume is lost during 1^st year with approximately up to 60% of loss of bone width during three years causing labial cortical plate position to shift medially to compensate for the loss of alveolar bone density and volume.^1,2

Seibert has classified the ridge defects as:

a) Class 1- loss of ridge width but normal ridge height

b) Class 2- loss of ridge height but normal ridge width

c) Class 3- loss of both height and width of the ridge.³

Hilt Tatum introduced the ridge splitting technique, also known as ridge expansion technique, widening technique, and bone spreading technique in the early 1970s for management of horizontal ridge augmentation.^4,5 This procedure reduces the patient’s number of appointments and placement of the implant in a single visit. This technique is used for the rehabilitation of atrophic ridges with horizontal bone defects (≥3.5 mm) in the maxilla or mandible.⁶ Detailed preoperative analysis of extra-oral, intra-oral, and radiographic examinations is of utmost importance for case selection. In this case report, we have described horizontal ridge expansion using modified ridge split technique along with implant placement and guided bone regeneration in the maxillary esthetic zone.

Case Presentation

A 21-year old male patient reported to the Department of Prosthodontics, Crown and Bridge including Implantology at Al-Badar Dental College and Hospital, Kalaburagi, Karnataka, with the chief complaint of missing front tooth due to trauma. On extraoral examination, there was no abnormality detected and no gross asymmetry was noted. Intraoral examination (Figure 1) revealed an edentulous space in relation to 21 with defective labial bone, Angle’s class 1 malocclusion, Ellis class 4 fracture in relation to 11, Ellis class 2 fracture in relation to 12, and attrition in relation to deciduous canines. The patient had neither systemic conditions nor deleterious habits.

Procedure

Preoperative radiographic evaluation was done with intraoral radio visio graphy (RVG), panoramic radiograph (OPG) and Cone Beam Computed Tomography (CBCT) scan (Figure 2). Preoperative routine blood examinations were carried out for appropriate treatment planning which showed no pathology. Clinical and radiographic examination showed that both ideal vertical bone height and inter arch space favoured implant placement. The ridge width of 3.2 mm was inadequate for implant placement. After thorough radiographic examination, the most desirable treatment plan was decided i.e. ridge split technique followed by bone grafting. Diagnostic impression was made, poured with dental stone and retrieved cast was studied.

An oral prophylaxis procedure was performed as preoperative preparation of the oral cavity. The patient was comfortably seated on the dental chair. Extraoral Betadine (5% Povidone iodine) was painted and moped off using cheatle forceps and gauze, also the subject was asked to rinse with 0.2% chlorhexidine digluconate mouthwash as a pre-surgical oral rinse for local disinfection. The surgical site was anesthetized with local anaesthesia Lignox 2% A (2% Lignocaine HCl with 1:80,000 Adrenaline) by administering right infraorbital nerve block, incisive nerve block, and local infiltration.

Mid-crestal incision followed by crevicular incisions extending till the distal line angles of the adjacent teeth were made along with two vertical relief incisions. A full-thickness mucoperiosteal flap was reflected to visualize the bone architecture using Glickman’s periosteal elevator. A No. 15 Bald Parker blade and mallet was used to give two vertical osteotomy relief incisions 1 mm mesially to the adjacent teeth at a depth of 2 mm with gentle tapping to relieve the future split. Horizontal decortication was done joining the apex of the vertical splits using 171 carbide bur using a micro motor with profuse irrigation with chilled saline. Midcrestal osteotomy incision was made on the crest of alveolar bone in the desired angle of pre-planned implant position. A chisel was used to create a greenstick fracture by digit supporting the buccal plate (Figure 3).

A 3.5 mm x 11.5 mm implant was inserted after a 13 mm osteotomy was created using a series of drills. The osteotomy was created with an initial guide drill and RVG was used to validate the desired angulation of the drill. By totally avoiding pressure on the buccal plate and maintaining tactile digit support on the buccal plate to prevent perforation so that it bisects the ridge crest and divides the cortical plates, the osteotomy preparation was directed to the palatal plate. A hinging of bony plates at the base of the ridge split osteotomy was made possible by extending the length of the osteotomy along the edentulous span much beyond the desired implant length.

An implant was placed using the motor driver at 20 rpm with 20 torque. The implant was kept away from the buccal plate and primary stability was achieved from the palatal plate. The implant mount was removed after judging the sub-crestal placement of the implant by 1.5 mm. Bio-oss bone graft was placed at the site and collagen (perio-col) membrane was placed over it and approximated. 3-0 silk sutures were placed to achieve primary closure. The patient was given postoperative instructions and medication.

Suture removal was done after two weeks of implant placement and interim prosthesis was delivered which was fabricated on the diagnostic cast by relieving the intaglio surface with no blanching creating pressure on or around the tissue surface above the submerged implant.

The patient was recalled after four months of implant placement for healing abutment placement. Modified Roll flap technique was performed to increase the thickness of soft tissue for aesthetic facial profile and to maintain good health of underlying bone. Acrylic tooth of interim prosthesis was trimmed and polished to the height of smile line followed by insertion (Figure 4). After two weeks, patient was called for an open tray impression using a customized impression tray of cold cure material. Tooth no.12 was restored using composite followed by tooth preparation of tooth no.11. Open tray impression copping was positioned and guide pin was tightened with prosthetic hex driver to achieve flush fit of copping with the fixture which was confirmed by RVG. After positioning the customised tray and verifying its orientation, a tiny layer of tray glue was applied.

Light body impression material was dispensed around the margins to be captured and heavy body impression was manipulated. The material was loaded and placed in the patient’s mouth till it sets. Shade selection was done under daylight. The impression was later disinfected and sent to the lab for fabrication of the cement-retained Porcelain Fused to Metal prosthesis. The final prosthesis was delivered, the fit of the prosthesis was checked and all the contacts in protrusive and excursive movements were checked using articulating paper for any deleterious forces, followed by RVG to verify the fit. The prosthesis was cemented using TYPE 1 GIC and excess cement was removed followed by RVG to check the flush fit and residual cement which needs to be removed. The patient has a post-implant follow-up of about a year and half (Figure 5).

Discussion

A full-thickness flap was reflected for better visualization of the operating site, for maintaining a bloodless field as partial thickness flap can induce bleeding and hamper accessibility.⁷ BP Blade no.15 was used to make incisions on soft and hard tissues. The vertical osteotomy incision on the buccal cortical plate was performed by keeping a safe distance of about 1 mm from the adjacent teeth (Limiting structure) to maintain blood supply. A firm tight grasp was used to hold the BP blade handle and controlled tapping strokes were applied with mallet at the site to the desired depth. Decortication was done on the apex of the vertical osteotomy incisions in a horizontal manner. The mid-crestal horizontal osteotomy incision on the ridge was carried out in the direction of the implant to be placed while supporting the cortical plates with firm fingers to have the tactile sensation of the blade angulation in space to avoid perforation of plates.⁸ After joining the vertical and horizontal cortical bone incisions, a greenstick fracture was created by placing the chisel in the split and doing controlled elevation of buccal plate.^9,10 Sequential drilling was performed in the desired angulation with firm finger support on the buccal cortical plate to have the tactile sensation of the drill angulation in space to avoid perforation of plates.^11,12

Scipioni et al., in 1994 described edentulous ridge expansion with a 98.8% implant rate over five years.¹ Several authors described ridge split technique in which crestal osteotomy incisions were continued on both sides causing a greenstick fracture of the cortical plate.9 Expanding the cortical plates to the appropriate size of between 3.2 mm and 6.6 mm with an implant (Figure 3), followed by either a two-step bone graft or the placement of the implant during the same session (single step). By separating the cortical plates, placing an implant, and guiding bone regeneration in a single visit, we merged single step and two step procedures in our case.

Ridge split with immediate implant placement and guided bone regeneration with collagen membrane barrier helps in better generation of bone volume which restores the function and esthetics of the patient lost due to trauma. This case report elaborates the steps performed during the surgical and prosthetic phase of implant placement in Seibert Class I using modified ridge split.

Conflict of interest

None

Funding

None