This report demonstrated the management of combined ridge defect and maxillary sinus pneumatization with simultaneous implant placement. One case with vertical and horizontal ridge deficiency and sinus pneumatization in the maxillary premolar area was indicated for ridge augmentation and sinus elevation before implant placement. Implant osteotomy was enlarged using a ridge expansion osteotome to 1 mm short of the sinus floor; sinus elevation was performed using sinus lift osteotomes; the implant was placed; bone graft and resorbable membrane were used to augment the remaining defect. The second stage was done after 6 months, followed by final restoration. The patient was reevaluated for 36 months following the final prosthesis. The surgical site healed without complication following implant placement. During the second stage, the implant was completely surrounded by bone, with bone covering the buccal aspect of the cover screw. The X-ray showed a 5 mm apical shift of the sinus floor at 6 months post surgery. At 12 months post loading, crestal bone loss to the level of the first thread was noted; no changes were observed at the sinus or surrounding teeth. Pocket depth ranged from 3–4 mm. No further bone loss or soft tissue contour change was noted at 18, 24, 30, and 36 months post loading. The combination of these three techniques with simultaneous implant placement as described in this report seems to be successful. Further research is needed to evaluate whether the combination of these techniques with simultaneous implant placement offers similar results when compared with the stage approach.
The ideal placement and restoration of dental implants are dependent on the presence of adequate bone volume and quality at the edentulous site. Alveolar bone loss can result from tooth extraction, infection, trauma, and pathology and can prevent implant placement in favorable positions and angulations.1 The morphology of a bony defect is an important factor in the selection of a method for ridge augmentation.2
Alveolar ridge defects can be classified, according to Seibert and Cohen, as horizontal, vertical, or combination vertical and horizontal bone loss.3 Horizontal bone loss is the most amenable to augmentation, and the combination of horizontal and vertical bone loss offers the lowest predictability for surgical correction.1
Several alveolar ridge augmentation techniques, including bone expansion,4–6 bone spreading,7,8 bone grafting,9–13 and guided bone regeneration,14–16 have been described in the literature.
Insertion of the implant into the posterior maxilla is more challenging owing to reduced bone quality and quantity.17–21 The presence of the maxillary sinus floor limits the available bone height for implant placement. Different methods, such as tilted implants, short implants, vertical bone augmentation, and sinus floor elevation, have been used to overcome these problems. Elevation of the sinus floor can be performed through a lateral window,22–24 or via a crestal access.4,6,25–28 The most commonly used technique is sinus floor elevation through a lateral window, which was first presented by Tatum in 1977 and was first published by Boyne and James in 1980.22,28–30 This bone augmentation procedure is considered to be invasive, time consuming, and expensive.24,31 Therefore, every effort to reduce its indication span should be encouraged.32
Elevation of the sinus membrane through a crestal approach using osteotome technique was introduced by Summers in 1994.4,6 When compared with the lateral window approach, the osteotome procedure offers the advantages of a more conservative surgical entry, more localized augmentation of the sinus, less operation time, and minimal postoperative discomfort.29,33–35
The combination of maxillary sinus pneumatization, buccolingual and apico-occlusal resorption patterns, and poor bone quality in the posterior maxilla poses a significant challenge to the clinician during implant placement. Comprehensive management of this area mandates meticulous diagnosis and treatment planning before implant therapy is initiated.34,36
The present case report demonstrates the management of combined (buccolingual and apico-occlusal) ridge defect and maxillary sinus pneumatization by ridge expansion with osteotomes, sinus floor elevation using osteotomes, and guided bone regeneration with simultaneous implant placement. Follow-up for 36 months after loading is presented.
A 42 year-old female patient was referred by her treating dentist to the Periodontics Division, Department of Oral Basic and Clinical Sciences, Faculty of Dentistry, King Abdulaziz University, for replacement of her missing maxillary left second premolar by implant. A review of the patient's medical history revealed a healthy nonsmoking individual, with no systemic contraindication for dental treatment. Dental history indicated that this tooth was extracted 12 years ago owing to fracture after endodontic treatment. Comprehensive periodontal examination revealed a healthy periodontium with no pathologic probing depth, good oral hygiene, and no bleeding on probing. Recession of 2 mm and 3 mm buccal to the maxillary left first premolar and first molar, respectively, was noted.
Clinical examination and bone sounding indicated the presence of a class III ridge defect3 with 4 mm bone loss in the apico-occlusal direction, and a 2 mm thick ridge buccolingually at the crest. The buccolingual thickness of the ridge increases gradually in the apical direction. Soft tissue height was acceptable at the extraction area. Radiographic evaluation affirmed the clinical diagnosis, showing a crater-shaped defect in the alveolar crest and sinus pneumatization, with 7 mm of bone remaining between the crest of the ridge and the sinus floor (Figure 1).
Suggested treatment as approved by the patient consisted of ridge expansion with osteotomes, sinus floor elevation using a crestal approach with sinus lift osteotomes, implant placement, and guided bone regeneration.
The patient was given 1 g of amoxicillin 1 hour before surgery and continued with 500 mg every 8 hours for 1 week.
Treatment was carried out under local anesthesia with local infiltration provided buccally and palatally. A crestal incision was made from the distal of the maxillary left first premolar to the mesial of the maxillary left first molar, and divergent releasing incisions remote to the defect area were used to facilitate closure and maintain adequate blood supply. A full-thickness flap was elevated (Figure 2). The proposed implant site was marked first with a 1.5 mm round drill, followed by a 1.5 mm twist drill, to a depth of 4 mm. A 1.5 mm guide pin was placed to verify implant positioning relative to the planned restoration. The 1.5 mm drill then was taken to a depth of about 1 mm from the sinus floor, as measured from the preoperative radiograph. This position was confirmed radiographically. To enlarge the osteotomy site, ridge expansion osteotomes (convex-tipped) with a 30 degree offset were used to the depth of the osteotomy in 0.5 mm increments, starting with a 2.0 mm osteotome (Figure 3), then using a 2.5 mm osteotome (we used a 3.5 mm tapered implant with a 2.4 mm diameter apically).
Sinus floor elevation was carried out after that, using 2.5 mm sinus lift osteotomes (concave-tipped) (Figure 4) by direct sinus floor infracture with the technique reported by Cavicchia et al,26 wherein the final osteotome were used to punch out the cortical plate of the sinus floor with the adherent membrane.
After sinus floor infracture, column mixtures of bovine bone (particles size 0.25–1.0 mm) and calcium sulfate (ratio 4∶1) were added to the osteotomy using a periodontal defect graft syringe and were apically displaced to the depth of the osteotomy using a sinus lift osteotome. Each 4.0 to 5.0 mm column of bone was used to create 1.0 mm of localized sinus floor elevation. This procedure was repeated until adequate elevation was attained to accommodate the selected implant length. The osteotomy (Figure 5) then was half-filled with the graft mixture, and a 3.5 mm tapered implant with 13 mm length was placed in an ideal position about 3 mm apical to the cementoenamel junction of adjacent teeth, leaving 4 mm of the buccal part of the implant exposed; then a cover screw was placed (Figure 6). Collagen membrane was trimmed to adapt to the surgical site, a bone graft (mixture of bovine bone and calcium sulfate, “ratio 4∶1”) was used to cover the exposed part of the implant and fill the defect (Figure 7), and the membrane was adapted to overlay the graft (Figure 8).
The periosteum at the base of the flap was incised carefully to allow stretching of the mucosa and tension-free adaptation of the wound margins. The flap then was secured using 5-0 Vicryl interrupted sutures (Figures 9 and 10). The patient was given nonsteroidal anti-inflammatory drugs and chlorhexidine mouth wash for 1 week post surgery.
Evaluation of graft healing
Sutures were removed after 14 days. Soft tissue healing was monitored carefully during the healing period so any early or late complications could be evaluated at the surgical site, along with the effects of these complications, if any, on graft healing and success. The patient was reevaluated after 1, 3, and 6 months.
After 6 months of healing, a crestal incision was made to expose the implant (Figure 11), a cover screw was removed, and a healing abutment was placed (Figure 12); the flap was sutured with 4-0 gut suture.
The final crown was placed after 4 weeks. The patient was reevaluated after 3, 6, 12, 18, 24, 30, and 36 months following placement of the final prosthesis.
The surgical site healed without complication or infection following implant placement. The patient reported minor discomfort during the second day post surgery; this was managed by analgesics, and no pain or discomfort was reported afterward.
Evidence of good clinical ridge contour was noted during the 5 months of healing.
During the second stage, the implant was completely surrounded by bone, with bone covering the buccal aspect of the cover screw (Figure 11). The X-ray showed a 5 mm apical shift of the sinus floor at 6 months post surgery (Figure 12). At 12 months post loading, crestal bone loss to the level of the first thread was evident (Figure 13); no changes were noted at the sinus or surrounding teeth. Pocket depth ranged from 3 to 4 mm. The implant was stable. No additional bone loss or soft tissue changes were noted at 18, 24, 30, and 36 months post loading (Figures 14 and 15).
This case report demonstrates a new technique for the management of combined ridge defect in the posterior maxilla. The patient had class III (buccolingual and apico-occlusal) ridge defect and maxillary sinus pneumatization. Ridge expansion with osteotomes was done first to minimize bone removal during osteotomy and condense the surrounding bone. Then, sinus floor elevation was performed using sinus lift osteotomes, and the remaining ridge defect was augmented using guided bone regeneration with simultaneous implant placement. Follow-up for 36 months after loading was also presented.
Ridge expansion with the use of osteotomes proved to be a reliable and noninvasive technique for correcting a relatively narrow edentulous ridge.37 This technique offers another advantage by compressing bone apicolaterally, thus producing a local increase in bone density.38–41 Survival and success rates of implants placed in the expanded ridge are consistent with those of implants placed in native, noncompressed bone.37
Sinus floor elevation with osteotomes proved to be more conservative, with more localized augmentation of the sinus, less operation time, and minimal postoperative discomfort.29,33–35 The narrow range of indications may be the main disadvantage. Several grafting materials have been used successfully in conjunction with this technique, and high implant survival rates have been reported with it.42–45
The guided bone regeneration technique has been used successfully to treat peri-implant bone defects at the time of implant placement, or to correct alveolar ridge defects before implant placement in animals and humans.46–49 Many different techniques and materials, including resorbable and nonresorbable membranes with autografts, allografts, xenografts, and alloplastic grafts, have been used with encouraging results.49–53 However, use of GBR principals for vertical bone augmentation still represents a challenge for the clinician, because of the technique-sensitive protocol that has to be applied to achieve predictable results.54
The combination of these three techniques with simultaneous implant placement as described in this report seems to be successful. It saved the patient time and effort as compared with the staged approach. Further research is needed to evaluate whether the combination of two or all these techniques with simultaneous implant placement offers similar results when compared with the staged approach.
Ali Saad Thafeed AlGhamdi, BDS, MS, is head of the Periodontic Division, and assistant professor and chairman in the Department of Oral Basic and Clinical Sciences, at King Abdulaziz University, Jeddah, Saudi Arabia. Address correspondence to Mr AlGhamdi at Department of Oral Basic and Clinical Sciences, Faculty of Dentistry, PO Box 109725, Jeddah 21351, Saudi Arabia. (e-mail: email@example.com)