John N. Kent

Sinus augmentation for dental implants: the use of autogenous bone.

Autogenous bone has been the material of choice at our institution since 1983. The criteria for a successful graft in the sinus have been fulfilled based on functional stability in patients followed-up over 10 years in selected cases. Of 173 implants placed into autogenous bone grafted sinuses, 20 have been lost in four patients. Long-term follow-up is recommended for all graft materials used to support posterior maxillary restorations.

Bone maintenance 5 to 10 years after sinus grafting

PURPOSEnThis radiographic study determined the amount of bone around hydroxyapatite (HA)-coated dental implants that were placed into bone-grafted maxillary sinuses.nnnPATIENTS AND METHODSnPostoperative complex motion tomograms using the Grossman technique were taken on 16 patients who had 27 maxillary sinus grafts performed using particulate autogenous iliac bone with and without demineralized bone, autogenous iliac corticocancellous block with and without demineralized bone, and autogenous jaw bone with demineralized bone. Bone levels were measured from the new floor of the grafted sinus to the apex of the implant and to the alveolar crest. The resulting bone level measures were compared with the type of graft used. All patients had been restored for 5 to 10 years after simultaneous graft and implant placement.nnnRESULTSnFor all patients summed together, the average amount of bone from the top of the graft to the apex of the implant was 3.3 +/- 3.1 mm, and the average amount of bone from the top of the graft to the alveolar crest was 17.6 +/- 3.1 mm. The average level of bone in the sinuses of patients grafted with autogenous iliac bone was greater than the average level of bone in those grafted with autogenous bone combined with demineralized bone.nnnCONCLUSIONnThe results of this study indicate that autogenous bone grafts are maintained in the maxillary sinus, but the results with autogenous bone alone are better than when demineralized bone is added. However, this difference may not be clinically significant.

Update on the Vitek partial and total temporomandibular joint systems

A retrospective recall study was done on 262 VK I (N = 138) and VK II (N = 124) (Vitek, Inc, Houston, TX) partial and total temporomandibular joints placed between 1982 and 1990. The cumulative success rate of VK I total joints observed for up to 10 years was approximately 20%, whereas the success rate of VK II total joints observed up to 6 years was approximately 80%. At the 5- to 6-year interval for each, these rates were 44% and 79%, respectively. Wear of the Teflon fluorinated ethylene propylene polymer surface was the primary reason for VK I failure; there was no material failure of the VK II prostheses. Slightly better pain relief, increase in interincisal opening, improvement in diet, and greater overall satisfaction were noted with the use of VK II. A highly significant improvement in success data was found if no surgery had been performed before either VK I or VK II total joint placement. Rib grafts were not particularly helpful after removal of total joint prostheses, particularly if the patient had a history of multiple surgeries. Total temporomandibular joint surgery must be reserved for patients in whom alternative surgical methods have failed or are no longer indicated. All total joint implants, particularly the VK I, must be observed closely with clinical examination and imaging and removed at the earliest sign of material failure.

HYDROXYLAPATITE AUGMENTATION OF ATROPHIC ALVEOLAR RIDGE.

Publisher Summary This chapter discusses the hydroxylapatite augmentation of atrophic alveolar ridge. Hydroxylapatite (HA), a highly biocompatible, osteoconductive calcium phosphate material has provided a permanent support matrix for the deposition of fibrous tissue and bone by direct chemical bonding mechanisms. In some of the class III and IV ridge deficiency patients, 12–20 grams of HA mixed with finely crushed autogenous cancellous iliac bone was used to provide increased strength to the severely atrophic alveolar ridges. Surgical technique involved subperiosteal pocket tunneling through vertical mucoperiosteal incisions with or without a blind submucosal vestibuloplasty. Injection of HA into these pockets was done with a variety of modified plastic syringes. Solidification of HA generally occurred by the fourth to sixth postoperative week permitting impressions for denture construction. Skin and mucosal graft vestibuloplasty, if needed to increase sulcus depth after hydroxylapatite augmentation, was usually possible after two months because of the intense fibrous tissue infiltration between HA particles. In most patients augmentation of alveolar deficient ridges with HA has resulted in a permanent improved ridge height and convex contour. The overlying soft tissue mucosa is nonmobile except in severe ridge deficiencies where post operative vestibuloplasties are required.

Autogenous Reconstruction of the Temporomandibular Joint

Recently, the temporomandibular joint has been reconstructed with a variety of alloplastic materials; however, functional results are often limited, and long-term stability of the reconstruction is questionable. In contrast, costochondral rib grafting with rigid internal fixation and a temporoparietal fascia flap allows complete functional reconstruction of the temporomandibular joint with autogenous tissue. Thirteen joint reconstructions in 11 patients were followed for up to 7 years and stability of the reconstruction was confirmed. The anterior incisal opening improved from a mean of 14 to 31 mm. Normal occlusal relationships were either reestablished or preserved. Joint pain was ameliorated. The preferred reconstruction of the temporomandibular joint is by autogenous tissue for disc and joint replacement. The treatment provides primary therapy in total joint reconstruction where tumor, trauma, or failed prosthetic joint replacement necessitate complete reconstruction.