Apical and Marginal Bone Alterations around Implants in Maxillary Sinus Augmentation Grafted with Autogenous Bone or Bovine Bone Material and Simultaneous or Delayed Dental Implant Positioning

Abstract Objective: A re-pneumatization phenomenon was recorded in sinuses grafted with different materials. The specific aims of this paper were to assess the dental implant survival rate and the behavior of marginal and apical bone remodeling around dental implants placed following sinus augmentation. Materials and methods: A retrospective study was conducted on consecutive patients treated in two surgical centers. Different surgical techniques were adopted for sinus augmentation: simultaneous or delayed dental implant insertion with bovine bone-material augmentation or autologous bone grafting (chin and iliac crest). Survival rates were recorded for the overall number of implants (patients of group A). Apical and marginal bone levels (ABL and MBL, respectively) were radiographically measured, and statistical analysis was performed in implants of a subgroup of patients (group B). Results: A total of 282 dental implants were positioned. Recorded cumulative survival rates (CSRs) were 95.6% and 100% for autogenous and bovine bone material, respectively, while CSRs at 2-year follow-up for immediate and delayed procedures were 99.3% and 96.5%. For the subgroup B, 57 sinus augmentation procedures were performed in 39 patients, with the positioning of 154 implants. Generally, the apical- and marginal-bone resorption of the bovine bone-material group was less than that of the autogenous group. The differences between the ABL values of the bovine bone-material and iliac-crest groups were statistically significant at 1 year, whereas this significance disappeared at the 2-year follow-up; tests showed that a statistical difference was recorded in the bovine bonematerial group between the 1- and 2-year follow-ups. With regard to MBL comparisons between simultaneous and delayed implantation, the differences maintained their significance at the 2-year follow-up also. Conclusions: Differences regarding apical bone alteration between autogenous bone from the iliac crest and bovine bone material at the 1- and 2-year follow-ups, as well as in the bovine bone-material group between the 1- and 2-year follow-ups, attested to slower but more prolonged physiologic bone remodeling in the bovine-graft-material group than in the autogenous-bone group. The MBL analysis showed that remodeling in the delayed implant group demonstrated a greater resorption in the cervical portion than was seen in the simultaneous implant group. Key words: augmentation techniques, autologous bone graft, bone remodeling, bovine bone material, dental implants, sinus bone resorptio

A Comparative Volumetric Study of Symphysis Donor Defects, Unfilled or Filled with Bone Substitute

Abstract Objectives: Background Intraoral autogenous bone grafts are a convenient source of bone in reconstruction of the residual ridge before dental implant placement. Purpose: The aim of this study was to evaluate bone volume of symphysis donor defects filled with bone substitute compared with unfilled symphysis donor defects. Patients, Materials and Methods: The study included 26 patients who underwent either alveolar ridge reconstruction or maxillary sinus elevation. Two groups were studied: symphyseal donor defects filled with bone substitute and unfilled symphyseal donor defects. Pre- and postoperative volumetric variables were determined using computed tomography scans and the software program SimPlant® (Materialise Dental Italia, Roma, Italy). Results: At 6 months postsurgery, the filled donor defects exhibited a significant increase in bone volume compared with unfilled donor defects (97.7% and 73.4%, respectively). At 18 months postsurgery, volume of unfilled donor defects was reevaluated with no significant increase in bone volume. Conclusions: Six months following block harvesting procedure, filled donor defects maintained bone volume, while unfilled donor sites generated defects that cannot achieve full regeneration; even not 18 months postblock harvesting

Dealing with dental implant failures

An implant-supported restoration offers a predictable treatment for tooth replacement. Reported success rates for dental implants are high. Nevertheless, failures that mandate immediate implant removal do occur. The consequences of implant removal jeopardize the clinician's efforts to accomplish satisfactory function and esthetics. For the patient, this usually involves further cost and additional procedures. The aim of this paper is to describe different methods and treatment modalities to deal with dental implant failure. The main topics for discussion include identifying the failing implant, implants replacing failed implants at the exact site, and the use of other restorative options.When an implant fails, a tailor made treatment plan should be provided to each patient according to all relevant variables. Patients should be informed regarding all possible treatment modalities following implant failure and give their consent to the most appropriate treatment option for them