International Journal of Periodontics & Restorative Dentistry, 05/2001

An investigation of the periodontal literature reveals four critical factors necessary for a regenerative response in the treatment of intrabony defects. These include root preparation to remove toxins and altered cementum, space creation by the graft or membrane barrier for migration of progenitor cells, stabilization and flap coverage of the graft, and use of a membrane barrier or enamel matrix derivative (EMD). This article reviews the literature supporting this concept and presents a clinical decision tree to determine when to use EMD alone or with autogenous grafts and membrane barriers in the treatment of defects of varying morphologies. The clinical decision tree is designed to increase the predictability of a positive clinical response. Cases are shown to demonstrate the indication for each treatment.

A growing number of clinical reports show that early and immediate loading of endosseous implants may lead to predictable osseointegration; however, these studies provide mostly short- to mid-term results based only on clinical mobility and radiographic observation. Other methods are needed to detect the possible presence of a thin fibrous interposition of tissue that could increase in the course of time and lead to clinical mobility. A histologic evaluation was performed on two immediately loaded Osseotite implants retrieved after 4 months of function from one patient. He had received a total of 12 implants in the mandible, of which six were immediately loaded and six were left to heal in a submerged way. Clinical and histologic osseointegration was consistently achieved for both of the retrieved immediately loaded implants. Osteogenesis and bone remodeling on the Osseotite surface were not impeded by immediate loading as shown by histomorphometric evaluation, which revealed high levels of bone-to-implant contact ranging from 78% to 85%. This immediate loading protocol involving bilateral splinting of six Osseotite implants in the mandible proved to be successful after 4 months of loading. Further long-term clinical and histologic studies are needed before introducing this immediate loading protocol as a routine procedure in implant therapy.

The objective of this study was to examine alveolar ridge augmentation following implantation of recombinant human bone morphogenetic protein (rhBMP-2) with an allogeneic freeze-dried demineralized bone matrix (DBM) mixed with autologous blood. A second objective was to evaluate bone-to-implant contact in induced bone. Bilateral surgically created supraalveolar ridge defects in five young adult beagle dogs were implanted with the rhBMP-2-DBM-blood device. Transmucosal dental implants were placed at weeks 8 and 16 postsurgery. The animals were euthanized 24 weeks following ridge augmentation. Healing was uneventful in all animals. Radiographic observations indicated substantial bone formation, including regions of radiolucency, at week 8. At week 16, the radiolucencies were generally resolved, and the trabecular structure of the induced bone resembled that of the adjacent residual bone. There were no remarkable differences in radiographic observations between weeks 16 and 24 after ridge augmentation. Histologic analysis revealed dense woven and lamellar induced bone. Any residual DBM appeared remineralized, at least in part. A large portion of the dental implants (≈ 70%) were housed in induced bone with evidence of limited crestal resorption. There was no significant difference in bone density between induced and residual bone, and the levels of bone-to-implant contact were similar (≈ 55%). The rhBMP-2 construct used in this study has a potential to augment alveolar ridge defects. Also, no difference in levels of osseointegration may be expected in induced and residual bone following a two-stage procedure of rhBMP-2-induced ridge augmentation and dental implant placement.

Excessive pneumatization of the maxillary sinus subsequent to the loss of teeth frequently interferes with the placement of osseointegrated implants. Many techniques have been developed and tested to reduce the size and alter the anatomy of the sinus to augment the quantity of bone available for an adequate number of prosthetically well-placed implants of a satisfactory length. Most of these describe extensive one- or two-stage sinus grafting procedures that are usually performed through a lateral approach. A technique of localized elevation of the maxillary sinus floor through a less-invasive crestal approach is presented here. Ninety-seven implants were placed with this technique between 1991 and 1998. The healing was always uneventful, without any sign of pathologic reaction in the maxillary sinus. Eighty-six implants were successfully loaded for a period between 6 and 90 months (mean 35 months). Eight implants failed to integrate, and three were lost after different periods of function, for a cumulative success rate of 88.6%.

Complications of ridge reconstruction can delay healing or even cause total failure of the procedure, making implant placement impossible. Most intraoperative complications, such as insufficient material for a graft or inadequate range of a soft tissue flap, are the result of poor treatment planning or execution. Postoperative infection is usually associated with onlay, veneer, and J grafts and dehiscence. Resorption of the graft can range from minor (exposure of the heads of the fixation screws) to total. Retraction of a soft tissue flap is most likely where the vestibule is shallow or the muscle pull is great. It is important to discuss the risks and consequences of all potential complications with the patient before informed consent is obtained. This measure will help prevent another complication, patient dissatisfaction with the results of surgery.

The demands of current periodontal practice require that clinicians use varied approaches to resolve poor esthetic appearances. In particular, patients are becoming less and less accepting of exposed roots and lost interdental papillae, especially in the maxillary anterior sextant. This report describes a surgical technique that combines the advantages of a root-coverage procedure using subepithelial connective tissue grafts and an incision design that preserves interdental papillae, coupled with the use of enamel matrix derivative (Emdogain) to maximize the regenerative potential.

The authors report the clinical and histologic data on the healing of a severe periodontal lesion obtained in a one-walled intrabony defect using anorganic bovine bone under a bovine peritoneum-derived collagen membrane. Eight months after surgery, a bone-like tissue replaced the lost tissues. A biopsy of this tissue was carried out. In the part of the specimen closer to the residual bony wall of the original defect, anorganic bone particles (ABP) appeared to be surrounded by a layer of newly formed bone; its osteocyte lacunae were colonized by osteocytes from the host, and actively secreting osteoblasts were observed in many microscopic fields. No resorption phenomena were observed in the ABP. Newly formed cementum with actively secreting cementoblasts was present on the tooth surface, and well-oriented fibers inserting in both newly formed cementum and bone were observed. In an area far from residual bone, all ABP did not appear to be surrounded by newly formed bone. Osteocytic lacunae appeared not to be colonized by cells, and ABP was surrounded by dense connective tissue without osteoblasts near the grafted particles. A very limited amount of newly formed bone, without relations with ABP, was observed close to the root surface. From a clinical point of view, anorganic bone in association with a collagen membrane can be effective in the treatment of bony defects characterized by an unfavorable architecture. From a histologic point of view, the clinical appearance of bone regeneration is not always confirmed in the part of the defect far from the bony walls.

A retrospective quantitative radiographic analysis determined the effect of graft material and smoking status on the maintenance of graft height over 3 years. Analysis of variance models with planned comparison were constructed to compare mean graft change by (1) graft material and (2) smoking status. Maintenance of bone height was significantly greater in intraoral autogenous grafts versus allografts (P .05). The effect of smoking on implant loss revealed a significant difference in implant survival (P .05). Autogenous bone generally resulted in a more favorable outcome over a 3-year period. Smoking adversely impacted implant survival in sinus grafts.