A 65-year-old retired Caucasian male presented to the Western University of Health Sciences Dental Center expressing an interest in implants after consulting with a private practice periodontist and a dentist from a large implant dentistry practice. He had no medical conditions or known allergies, but reported a 40-pack-year history of using tobacco and quit just before attending the Dental Center. No caries or mucosal abnormalities were found during examination other than a combined periodontal endodontic lesion at tooth no. 3 and localized severe periodontitis at no. 31 and no. 30 with complete through-and-through furcation involvement. Tooth no. 18 protruded beyond the occlusal plane, and several areas of shallow facial abfractions were noted on mandibular incisor teeth. (See initial panoramic radiograph, Fig. 1.) For initial disease treatment, teeth no.3, no. 30, and no. 31 were gently extracted and the residual socket of no. 30 grafted with human cortical particulate allograft. While healing was uneventful and ridge width was preserved at no. 30, little bone remained at the no. 3 site (see Fig. 2). On the left side, similar low amounts of available bone prevented implant placement at the no. 14 implant site (see Fig. 3). Given the good overall health of the patient, continued tobacco abstinence, good oral mucosal health after initial therapy, and low amount of sinus anatomy complexity, we suggested lateral window sinus augmentation to the patient, and the patient accepted proposed treatment after explanation of risks, benefits, and alternatives to implant therapy.
All of the following surgeries were carried out under local anesthesia. The patient received one tablet of 0.25 mg triazolam the evening before the surgery appointment and was taking ibuprofen 600 mg every 6 h and amoxicillin 250 mg every 6 h for 1 week starting the evening before the surgery. Starting the second day after surgery, the patient was instructed to rinse twice daily with 0.5 oz. of chlorhexidine gluconate for 30 s after oral hygiene, and the patient was seen at least once 7 days after each surgical procedure for postoperative care and oral hygiene instruction.
Lateral window sinus augmentation was performed on each side during appointments spaced 3 months apart, following the technique developed by Tatum in 1974. For each site, a midcrestal mucoperiosteal incision with buccal releases was created, and the lateral Schneiderian membrane of the maxillary sinus exposed through an ovoid window osteotomy of about 15 mm diameter. Osteotomy was performed using a piezotome (Piezotome 2, Acteon North America, and Mount Laurel, NJ, USA). Thereafter, the Schneiderian membrane was reflected away from the inferior floor of the sinus cavity with a mushroom-shaped Piezotome insert (Sinus surgery kit, Acteon North America, Mount Laurel, NJ, USA) and Sinus curettes (Sinus surgery curette kit, ACE Surgical Supply, Brockton, MA, USA) until the inferior most 15 mm of the medial wall was felt and seen. During both surgeries, we noticed small tears of 5 mm in the mid-portion of the mobilized Schneiderian membranes and repaired those by placing a double layer of 2 cm × 2 cm × 1.5 mm thick collagen tape (RCT, cut to shape, ACE Surgical Supply, Brockton, MA, USA) over the tears, which stabilized the membrane. We then placed a 1:1:1 mixture of cancellous and cortical allograft (AlloOss, ACE Surgical Supply, Brockton, MA, USA) and bovine xenograft (NuOss, ACE Surgical Supply, Brockton, MA, USA) into the space created between the former floor of the sinus cavity and collagen tape-covered Schneiderian membrane. Buccal access windows were then covered with a resorbable collagen membrane (resorbable collagen, ConFORM, ACE Surgical, Brockton, MA, USA) as suggested by Wallace and Froum [16], and the surgical site closed with continuous sutures (PTFE 3-0, Cytoplast, Osteogenics, Lubbock, TX, USA). No complications were reported by the patient and only when questioned he reported a short-lived episode of postnasal drip with few embedded “sand grains” after the surgery on the left side. We waited then for 10–12 months prior to further evaluation to allow complete dissolution of allograft [17] and allow complete bone formation [18].
A year later, we requested cone beam computed tomography for both posterior maxilla sites, and we found incomplete bone growth in the sinus. On the right side, bone growth had occurred only distal to the desired implant site, and there was an ovoid extension of sinus into the area planned for implant placement (Fig. 4). On the left side, a finger-like extension of sinus had developed between grafted bone and the former inferior medial wall of the sinus (Fig. 5). After explanation of findings, treatment alternatives, and risks and benefits of proposed treatments, the patient agreed on continuing with additional bone grafting.
For the right side, we decided to augment the area of insufficient bone using a balloon dilation technique through a subantral approach since the area of the missing bone was nearly spherical and centered at the no. 3 site. We also decided to place an implant simultaneously since primary stability seemed likely with the consistent thickness of 5 mm available bone at the no. 3 site, consistent with the recommendation by Pjetursson and Lang [19]. We created sinus access in a similar fashion as developed by Tatum in the 1970s and described by Misch [20] and performed sinus augmentation with a balloon technique as described for lateral window augmentation by Muronoi et al. [6]. (See Fig. 6 for the actual procedure, Fig. 7 for a diagram.) For this surgery, we created a mucoperiosteal flap with buccal releases for improved access (Fig. 6a, b) and created an osteotomy using osteotomy drills (Fig. 6c; Zimmer implant surgical kit, Zimmer, Carlsbad, CA, USA). Since there was sufficient ridge width and the bone was hard, we opted not to use Summer’s technique [21] but used drills to take the osteotomy to its final width that was slightly undersized for a 4.7-mm implant, but wide enough to allow insertion of a balloon dilator (straight model, Osseous Technologies of America, Hamburg, NY, USA). Drilling of the osteotomy stopped short 1 mm of the sinus floor. Prior to balloon dilation, we mobilized the Schneiderian membrane by gently infracturing small segments of the osteotomy floor using thin flat-ended osteotomes (ACE Surgical Supply, Brockton, MA, USA). For this, we started in the center of the osteotomy, advanced the depth of the infracture by 1 mm with a mallet and worked in a spiral fashion to the outer limits of the osteotomy floor and apical most 2 mm of the osteotomy wall. We then used a larger flat osteotome to advance the entire floor of the osteotomy by another millimeter, which resulted in a rubber-like mobility of the osteotomy floors. We verified the integrity of the membrane by gentle probing with a WHO probe and inserted the balloon dilator (Fig. 6d–g). We then slowly inflated the balloon dilator with 1 ml of saline, verified integrity of the membrane again, placed two sheets of 1 cm × 1 cm × 1.5 resorbable collagen tape, followed by 0.5 ml allograft and a 4.7 × 10 mm rootform implant (Fig. 6h–j; Tapered Screw-Vent TSVWB10, Zimmer, Carlsbad, CA, USA), which achieved good primary stability in excess of 30 Ncm. We placed a cover screw, replaced the flap, and sutured it with a continuous chromic gut 4-0 suture (Fig. 6k). Postoperative radiographs verified implant placement and showed good confinement of graft material around the implant (Fig. 6l). Healing was uneventful with only mild short-lived postoperative pain for a few days, and implant uncovery 12 months later revealed a firmly embedded implant.
For the left side, we decided to access the sinus using a lateral window as the area of deficient bone was much larger in size and more complex in shape. We also decided to approach this area from the palate, as the defect was closer to the palate and required much less bone removal as a buccal approach. Most importantly, we were already familiar with the anatomical structures on the lower medial wall of the sinus in the access area as we visualized this area during the first graft surgery and CT scans showed no signs of larger intraosseous vasculature in the area. Given this specific case, and knowledge of the vascular anatomy of the maxillary sinus in the surgical area (Fig. 8, based on CT scans of this patient and Bailey et al.’s work [22]), we felt that our approach would not invade the zone of risk for bleeding complications. We performed the surgery similar to a conventional lateral window sinus augmentation surgery using piezosurgery and a buccal approach, except from the palatal side of the alveolar ridge and staying clear of the greater palatine neurovascular bundle (Fig. 9). Here, we created a mucoperiosteal flap with vertical release at no. 13 (Fig. 10a, b). Using a piezotome and piezosurgery inserts (Piezotome 2, Acteon North America, Mount Laurel, NJ, USA), we created a rectangular window over the bony defect, avoiding any vascular structures (Fig. 10c). Using piezosurgery inserts and hydraulic pressure (IntraLift Kit, Acteon North America, Mount Laurel, NJ, USA), we carefully removed the Schneiderian membrane from the finger-like defect (Fig. 10d–f). We then placed a root-form 4.7 mm × 10 mm implant (Fig. 10f; Tapered Screw Vent TSWB10, Zimmer, Carlsbad, CA, USA) according to standard protocol and achieved good primary stability in excess of 30 Ncm. We placed a strip of resorbable collagen tape over any exposed Schneiderian membrane, grafted the site with 1.2 ml cortical particulate allograft (LifeNet Health, Virginia Beach, WA, USA) and placed a resorbable collagen membrane (ConFORM, ACE Surgical Supply, Brockton, MA, USA) over the palatal access window (Fig. 10g–i). We then covered the implant and graft with the palatal flap and sutured it with PTFE 3-0 (Cytoplast, Osteogenics Biomedical, Lubbock, TX, USA) continuous and horizontal mattress sutures (Fig. 10j). A postoperative radiograph showed good containment of the graft material (Fig. 10k).
Healing was uneventful with little discomfort reported by the patient during the first week, and implant uncovery revealed an implant firmly embedded in bone after 12 months. A third implant was placed at the no. 30 site and supraerupted no. 18 extracted as planned. Restoration of the implants was uneventfully performed by senior dental students supervised by various prosthodontists (Fig. 11). Periodontal maintenance was regularly performed, and 3 years after implant placement, there is no significant bone loss (Fig. 12), and probing depth remains at 2 to 4 mm with no bleeding on probing.
