Incorporation and Remodeling of Bone Block Allografts in the Maxillary Reconstruction: A Randomized Clinical Trial.

BACKGROUND: Severe alveolar atrophy often presents a challenge for the implant surgery. The significant lack of bone in the alveolar ridges may compromise the final restorations both from the aesthetic and functional standpoints. OBJECTIVES: To evaluate the behavior of bone block allografts for the maxillary augmentation and to investigate its incorporation, remodeling, and implant survival rates in two different healing time points. MATERIAL AND METHODS: Sixty-six consecutive patients (52 female/14 male, mean age: 57.95 ± 9.06 years old), presenting 113 atrophic alveolar ridges underwent maxillary augmentation with fresh-frozen allogeneic bone blocks from tibia. Patients were randomly assigned in two groups: Group 1-patients who would wait 4 months for implant placement after grafting, and Group 2-patients who would wait 6 months. Events of infection, suture dehiscence or mucosal perforation were recorded. Cone-beam computed tomography scans were compared volumetrically between the time of the grafting surgery and reentry procedure after incorporation. Biopsies were collected and subjected to histological, histomorphometric and immunehistochemical analysis. RESULTS: A total of 305 implants were placed in the reconstructed sites. The mean resorption rate in Group 1 (13.98% ± 5.59) was significantly lower than Group 2 (31.52% ± 6.31). The amount of calcified tissue, newly formed bone and remaining graft particles demonstrated no difference between groups. The samples showed evident immunolabeling for the podoplanin protein in both groups. The implants cumulative survival rate was 94.76%. CONCLUSIONS: The findings of the present study indicate that there is a significant difference regarding the resorption of the grafts when waiting 4 or 6 months before placing the implants, even though no difference was found in the histological, histomorphometric, and immunohistochemical features. Both 4-month and 6-months healing times are suitable for the implant placement.

Fresh-Frozen Bone Allografts in Maxillary Alveolar Augmentation: Analysis of Complications, Adverse Outcomes, and Implant Survival.

BACKGROUND: Success of any bone augmentation procedure is dependent on several factors. Because complications occur in some cases, the aims of this study are to analyze adverse events associated with placement of fresh-frozen bone allografts (FFBAs) during alveolar ridge augmentation and to assess 1-year survival of dental implants placed in reconstructed sites. METHODS: Fifty-eight consecutive patients (15 males and 43 females, aged 38 to 76 years; mean age: 58 ± 9.2 years) requiring maxillary bone reconstruction prior to implant placement were enrolled in this study. A total of 268 implants was subsequently placed in sites reconstructed with FFBAs. There were 22 posterior grafted sites, 19 anterior, and 17 full-arch sites. After a 4- to 6-month integration period, all patients received an implant-supported fixed prostheses. Complications occurring during treatment and the 12-month follow-up period were recorded and evaluated. RESULTS: Thirteen of 58 (22.41%) patients experienced some kind of complication in the receptor site. Infection occurred in six (10.34%) individuals, dehiscence in five (8.62%), and mucosal perforation in seven (12.07%). Adverse outcomes categorized as partial and total graft loss occurred in four (6.90%) and three (5.17%) patients, respectively. Implant failure rate was 16 (5.97%) of the 268 fixtures placed in 12 (20.70%) of 58 patients. CONCLUSIONS: Infection and suture dehiscence are significantly correlated with graft loss in a maxillary FFBA augmentation. Patients with full-arch grafting reconstructions lost significantly more implants. Early diagnosis and prompt management of adverse events seem to be of great importance in prevention of total graft loss.