International Journal of Periodontics & Restorative Dentistry, 06/2009

This second article in a three-part series on the use of artificial gingiva in fixed partial restorations focuses on diagnosis and treatment planning. Often, traditional treatment of complicated situations can result in a definitive restoration that is less than esthetic. With appropriate planning that incorporates thorough clinical examinations, three-dimensional imaging, diagnostic wax-ups, and consideration of patient expectations, a modified approach to ridge augmentation, implant placement, and prosthetic reconstruction can lead to an ideal restoration that incorporates artificial gingiva.

The objective of this proof-of-principle study was to examine the potential for improved bone regenerative outcomes in maxillary sinus augmentation procedures when recombinant human platelet-derived growth factor BB (0.3 mg/mL) is combined with particulate anorganic bovine bone mineral. The surgical outcomes in all treated sites were uneventful at 6 to 8 months, with sufficient regenerated bone present to allow successful placement of maxillary posterior implants. Large areas of dense, well-formed lamellar bone were seen throughout the intact core specimens in more than half of the grafted sites. Abundant numbers of osteoblasts were noted in concert with significant osteoid in all sites, indicating ongoing osteogenesis. A number of cores demonstrated efficient replacement of the normally slowly resorbing anorganic bovine bone mineral matrix particles with newly formed bone when the matrix was saturated with recombinant human platelet-derived growth factor BB.

Root coverage is the goal of periodontal plastic surgery when treating gingival recessions. The aim of the present study was to evaluate the clinical results 1 year after treatment with an envelope connective tissue graft technique for single recessions. Forty consecutive patients with single recessions were treated. At baseline and 1 year after surgery, recession, probing pocket depth, clinical attachment level, and keratinized tissue height were recorded. After 1 year, the mean differences in recession (3.12 ± 0.90 mm), clinical attachment level (3.92 ± 1.00 mm), keratinized tissue height (3.75 ± 0.95 mm), and probing pocket depth (0.50 ± 0.64 mm) were statistically significant. Mean root coverage was 95.54% ± 11.43%; 85% of the treated cases achieved complete root coverage. The envelope connective tissue graft technique showed high predictability in the treatment of single recessions.

Recent observations suggest that less bone loss may result from placing a more medialized abutment on an implant (platform switching). The objective of this study was to measure the radiographic crestal bone loss and biologic width around conventional and platform-switched implants. Implants were randomly assigned into conventional or switched categories within the same prosthesis. Twenty-five implants were placed and observed in the mandibles of 10 patients for 2 years. A regression analysis demonstrated a significant difference between groups (P = .0001). These findings suggest that less crestal bone loss occurs around a platform-switched dental implant versus a conventional implant.

The aim of this histologic and histomorphometric study was to evaluate the periimplant bone formation around one-stage surface-modified implants that were retrieved after a healing period of 4 weeks in humans. Three patients with mandibular partial edentulism participated in the study. An implant was inserted in the posterior mandible of each patient. All implants were retrieved after a 4-week healing period. Before retrieval, all the implants were clinically osseointegrated and immobile. Around all implants, mature compact preexisting bone, lined by newly formed strongly stained bone, was found. The bone-implant contact percentages were 52.0% ± 2.5%, 61.0% ± 2.9%, and 42.0% ± 6.9%, respectively, in the three included patients. These high bone-implant contact percentages observed in an early phase of healing are probably related to the microporous structure of both surfaces and their high hydrophilicity.

The complete dental rehabilitation of a patient with a failing dentition using fixed implant-supported prostheses requires carefully planned and well-sequenced treatment. This case report presents the treatment steps and sequencing for a patient in whom removable provisional prostheses were not an option. While an immediate loading protocol was used in the mandible, a staged approach featuring strategic extractions and implant placement in several phases was applied in the maxilla. The major advantage of this treatment protocol was that the patient was maintained in fixed prostheses throughout the treatment.

Whereas the majority of endosseous dental implants have threaded screw geometries, press-fit implants with a sintered porous surface (SPS) geometry integrate via three-dimensional bone ingrowth. These two classes of implants are suited for different site conditions and, when used appropriately, will provide optimal and minimally invasive treatment protocols. The present report argues that generally, threaded screw implants perform best in long lengths (with a "defined intrabony length" above 8 mm) and denser bone, while press-fit SPS implants perform optimally at short lengths ("defined intrabony length" of 5 mm or less) and in primarily cancellous bone. Threaded implants are more appropriate for immediate placement and immediate loading, while press-fit SPS implants perform well in resorbed posterior sites, including maxillary sites with as little as 3 mm of subantral bone. Understanding the benefits and limitations of these two implant concepts is key to successful and minimally invasive implant treatment.

A 66-year-old patient was referred to the Periodontal Clinic at Case Western Reserve University for implant placement in the mandibular left first molar area. The patient reported a history of oral bisphosphonate intake for the last 7 years for the treatment of osteoporosis. Autogenous bone block grafting was planned to augment the ridge before implant placement. The surgery was performed under local anesthesia, and the implant was successfully placed 8 months after ridge augmentation. Healing was uneventful postoperatively, and the buccolingual width of the ridge increased significantly, allowing placement of a 5-mmdiameter dental implant. The patient showed proper healing of both the donor site and the recipient site, in spite of the long-term oral bisphosphonate therapy, with no resulting osteonecrosis of the jawbone.

Freeze-dried bone allograft is an interesting treatment alternative to autogenous bone grafts. This clinical report presents a 3-year follow-up of an atrophic maxilla treated with freeze-dried bone allograft. Ridge augmentation was conducted with freeze-dried tibial allografts. Eight implants were used to support a full-arch prosthesis. Three years later, clinical and radiographic follow-up showed bone surrounding the dental implants. Histologic sections showed the presence of biologically active bone. This clinical case supports the use of freeze-dried allograft as an alternative for the reconstruction of the atrophic maxilla.

Autogenous bone grafts obtained from the mandibular symphysis or ramus are the primary donor sites for harvesting bone in the oral cavity to correct ridge deficiencies. Although such bone grafts can be successful, several concerns remain, such as donor site morbidity, nerve paresthesia, devitalization of natural teeth, and postoperative complications (eg, swelling, discomfort, and pain). To avoid these concerns and overcome the limited amount of autogenous intraoral bone for grafting, allogeneic block grafts were introduced. The purposes of this paper were to introduce allogeneic block grafts, demonstrate the integration of these allogeneic block grafts into the recipient site by detailed histology, and describe the step-by-step surgical technique of how this graft was used in a patient. A literature search was conducted to identify papers related to allogeneic block grafting, and papers were reviewed and summarized. The advantages and disadvantages of allogeneic block grafting were presented based on the literature and the authors' experience. One patient treated with allogeneic block graft was illustrated. The histologic evidence obtained from this patient indicated good bone remodeling and significant amount of new bone formation. The literature and clinical experience have shown that allogeneic block grafts can be used successfully to augment deficient ridges.