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Inside Dentistry
March 2016
Volume 12, Issue 3

Case Examples

Case 1

A 62-year-old systemically healthy man was referred to the postgraduate periodontics department at Rutgers School of Dental Medicine in Newark, New Jersey, for fixed prosthetic rehabilitation of the left posterior maxilla. Clinical and radiographic (Figure 1) evaluation revealed a non-restorable tooth No. 12 and pneumatized sinus in area 14. Due to poor root anatomy of tooth No. 15, conventional fixed prosthetics was contraindicated. It was proposed to place implants in sites 12 and 14 for implant-supported restorations. Immediate implant placement was not recommended due to presence of periapical pathology in area 12. Site development utilizing the trephine core/osteotome technique was proposed in area 14.

The surgical procedure was performed under local anesthesia (2% lidocaine, 1:100,000 epinephrine). Palatal crestal as well as intrasulcular incisions were made, and full-thickness mucoperiosteal flaps were reflected on the buccal. A trephine bur 2 mm less in diameter than the bucco-palatal width of the molar socket was used to create a core that was apically displaced using gentle malleting forces on osteotomes of similar diameter to elevate the sinus floor (Figure 2). The site was packed with mineralized cortical allograft and a resorbable membrane was placed. The flaps were carefully sutured with 4.0 Vicryl® (Johnson & Johnson, www.jnj.com) to attempt tension-free primary closure. Tooth No. 12 was extracted; the socket was curetted and grafted at the same visit. Radiographs were made following the surgical procedure (Figure 3) and 4 months following site development. Two tapered implants (4 & 5 mm x 11.5 mm) were placed in the maxillary left first premolar and first molar locations (Figure 4). The implants were made of commercially pure titanium with a roughened surface (Biomet 3i, www.biomet3i.com). A 500-mg dose of amoxicillin was prescribed three times per day for 7 days postoperatively. Ibuprofen (600 mg) was prescribed as needed. The patient was instructed to use 0.12% chlorhexidine gluconate (Peridex™, 3M ESPE, www.3mespe.com) rinse twice daily for 10 days. A soft diet and appropriate oral hygiene were recommended for 2 weeks.

Sutures were removed 14 days after the surgical procedure. The postoperative recovery was uneventful. The patient was examined clinically and radiographically each week in the first month after surgery and twice a month in the subsequent 2 months. The healing process was uneventful. Four months after implant placement, a screw-retained metal-ceramic three-unit fixed partial denture was delivered. One year after prosthesis placement, the implants had clinical and radiologic stability (Figure 5). (See online exclusive schematics illustrating this surgical technique in Figure 13 through Figure 18.)

Case 2

A 58-year-old systemically healthy man was referred to the postgraduate periodontics department at Rutgers School of Dental Medicine for evaluation and treatment of the maxillary right first molar (Figure 6). Clinical and radiographic evaluation revealed recurrent subcrestal caries beneath the current prosthesis and the tooth was considered non-restorable. The authors proposed extraction with site development for future implant placement.

The surgical procedure was performed under local anesthesia (2% lidocaine, 1:100,000 epinephrine). The first molar was sectioned and atraumatically extracted using periotomes. Upon extraction, a buccal dehiscence was found. However, good interradicular bone remained. Vertical releasing incisions were made on the buccal aspect to evaluate the extent of the defect. A trephine bur was used to create a core, and a corresponding osteotome was used to gently implode the core, apically displacing the floor of the sinus membrane (Figure 7). The site was packed with mineralized cortical allograft and a resorbable membrane was placed over the socket, making sure to cover the buccal defect. Flaps were released on the buccal and carefully sutured using 4.0 Vicryl to achieve tension-free primary closure. Radiographs were made following the surgical procedure (Figure 8). A 500-mg dose of amoxicillin was prescribed three times per day for 7 days postoperatively. Ibuprofen (600 mg) was prescribed as needed. The patient was instructed to use 0.12% chlorhexidine gluconate rinse twice daily for 10 days. A soft diet and appropriate oral hygiene were recommended for 2 weeks.

Sutures were removed 14 days after the surgical procedure. The postoperative recovery was uneventful. The patient was examined clinically and radiographically each week in the first month after surgery and twice a month in the subsequent 2 months. The healing process was uneventful. There were no sinus complications. A tapered implant (5 mm x 11.5 mm) was placed in the maxillary right first molar position 4 months following site development (Figure 9). A screw-retained metal-ceramic implant crown was delivered 6 months following implant placement. One year after prosthesis placement, the implant was clinically and radiographically stable (Figure 10).

Discussion

Sinus augmentation procedures are widely performed to correct vertical deficiencies encountered in the posterior maxillary region to enable optimal implant placement. While the lateral window approach has been used successfully as a sinus augmentation procedure, there are several disadvantages to this technique. It is more invasive in comparison to an internal approach, and technically more demanding when adjacent teeth are present. The risks of membrane perforation as well as postoperative complications are higher.22 Therefore, a less invasive technique designed to achieve the same goals may prove beneficial.

The trephine core technique is advantageous in a clinical setting. It is a sinus augmentation and site development procedure that is less invasive than the lateral window approach. While membrane perforation is a potential complication, this procedure has fewer postoperative complications and less risk of membrane perforation than the lateral window technique since the autogenous core is attached to the schneiderian membrane, allowing a cushion between surgical instruments and the floor of the sinus. It is a relatively simple procedure with short chairside time, allowing for increased case acceptance.

The modified technique of the trephine core/osteotome procedure can be used in different clinical settings. The technique is useful in cases such as: 1) single edentulous sites where simultaneous implant placement is not achievable; 2) compromised single molar sites where anatomical restrictions and adjacent teeth complicate the lateral window approach;16 3) at the time of maxillary first molar extractions; and 4) when employing multiple trephine cores to augment the sinus for long span edentulous sites in the posterior maxilla. Anatomical considerations that may be encountered, such as an uneven sinus floor, or a thicker schneiderian membrane, can be surgically managed applying this technique in combination with piezosurgery to successfully displace the cores (Figure 11 and Figure 12). Through the use of slow controlled malleting, extensive augmentation of the sinus can be accomplished from the crestal approach rather than the lateral window approach. Additionally, unlike the conventional Summers technique, this novel approach allows multiple site developments for the addition of multiple implant fixtures performed in a single surgical procedure.

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