Background:Although autografts are the standard procedure for bone grafting, the use of bone regeneration by means of dental pulp stem cell is an alternative that opens a new era in this field. Rigenera Protocol is a new technique able to provide the surgeon autologous pulp micro-grafts.Materials and Methods:At the Department of Oral Surgery, Don Orione Hospital, Bergamo, Italy, one patient underwent sinus lift elevation with pulp stem micro-grafts gentle poured onto collagen sponge. A CT scan control was performed after 4 months and DICOM data were processed with medical imaging software which gives the possibility to use a virtual probe to extract the bone density. Pearson's Chi-square test was used to investigate difference in bone density (BD) between native and newly formed bone.Results:BD in newly formed bone is about the double of native bone.Conclusion:This report demonstrated that micro-grafts derived from dental pulp poured onto collagen sponge are a useful method for bone regeneration in atrophic maxilla.

In the last decade several studies have been performed to evaluate the clinical outcome of implants inserted into grafted mandibles with autologous bone, but none is available on mandibles grafted with fresh-frozen bone. Thus, we planned a retrospective study on a series of implants inserted into homologue fresh-frozen bone to evaluate their clinical outcome. Twenty-one patients were operated on, 28 onlay grafts were inserted into the mandible, and 63 implants placed. Patients had total and partial edentulism in 11 and 10 cases, respectively. The mean follow-up was 20 months. No or reduced crestal bone resorption was considered an indicator of success rate to evaluate the effect of several host-, implant-, and occlusal-related factors. The difference between the implant-abutment junction and the bone crestal level was defined as the implant abutment junction (IAJ) and calculated at the time of operation and during follow-up by means of radiographs. Delta IAJ, the difference between theIAJ at the last check-up and the IAJ recorded just after the operation, were stratified according to variables of interests. Kaplan-Meier algorithm and Cox regression were then performed to detect those variables statistically associated with the delta IAJ. Only 2 of 63 implants were lost (i.e., survival rates = 96.8%) and no differences were detected among the studied variables. On the contrary, Cox regression showed that prosthetic restoration (i.e., removable dentures) was the only factor correlated with a statistically significant lower delta IAJ (i.e., reduced crestal bone loss) and thus a better clinical outcome. Implants inserted into mandibles grafted with fresh-frozen bone allografts have high survival rates and success rate, which are comparable with those obtained with autologous iliac crest bone grafts.

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Objective:Narrow diameter implants (NDI) (i.e. diameter <3.75 mm) are a potential solution for specific clinical situations, such as reduced interradicular bone, thin alveolar crest and replacement of teeth with small cervical diameter. NDI have been available in clinical practice since the 1990s, but only few studies have analyzed their clinical outcome and no study have investigated NDI inserted in fresh-frozen bone (FFB) grafts. Thus, a retrospective study on a series of NDI placed in homologue FFB was designed to evaluate their clinical outcome.Material and Methods:In the period between December 2003 and December 2006, 36 patients (22 females and 14 males, mean age 53 years) with FFB grafts were selected and 94 different NDI were inserted. The mean follow-up was 25 months. To evaluate the effect of several host-, surgery-, and implant-related factors, marginal bone loss (MBL) was considered an indicator of success rate (SCR). The Kaplan Meier algorithm and Cox regression were used.Results:Only 5 out of 94 implants were lost (i.e. survival rate - SVR 95.7%) and no differences were detected among the studied variables. On the contrary, the Cox regression showed that the graft site (i.e. maxilla) reduced MBL.Conclusions:NDI inserted in FFB have a high SVR and SCR similar to those reported in previous studies on regular and NDI inserted in non-grafted jaws. Homologue FFB is a valuable material in the insertion of NDI.

Zirconium oxide (ZO) has outstanding mechanical properties, high biocompatibility and high resistance to scratching. Since dental implants are made with ZO and the genetic effects of ZO on osteoblasts are incompletely understood, we used microRNA microarray techniques to investigate the translation process in osteoblasts exposed to ZO. By using miRNA microarrays containing 329 probes designed from Human miRNA sequences, we identified in osteoblast-like cells line (MG-63) cultured on ZO disks several miRNA whose expression was significantly modified. The most notable regulated genes acting on osteoblasts are: NOG, SHOX, IGF1, BMP1 and FGFR1. The data reported below represent the first study on translation regulation in osteoblasts exposed to zirconium and one in which the effect of ZO on bone formation has been detected.