Soft tissue-based registration of intraoral scan with cone beam computed tomography scan.

The aim of this study was to evaluate a novel soft tissue-based method to register an intraoral scan (IOS) with a cone beam computed tomography (CBCT) scan. IOS and CBCT data were obtained from eight dentate patients (mean age 21±2 years; three male, five female) and 14 fully edentulous patients (mean age 56±9 years; eight male, six female). An algorithm was developed to create a soft tissue model of the CBCT scan, which allowed a soft tissue-based registration to be performed with the IOS. First, validation was performed on dentate jaws with registration of the palatal mucosal surface and accuracy evaluation at the level of the teeth. Second, fully edentulous jaws were registered using both the palatal and alveolar crest mucosal surfaces. Distance maps were created to measure the method accuracy. The mean registration error was 0.49±0.26mm for the dentate jaws. Registration of the fully edentulous jaws had a mean error of 0.16±0.08mm at the palate and 0.16±0.05mm at the alveolar crest. In conclusion, the high accuracy of this registration method may allow the digital workflow to be optimized when no teeth are available to perform a regular registration procedure.

Retrospective evaluation of 211 patients with maxillofacial reconstruction using parietal bone graft for implants insertion.

PURPOSE: For a century, autologous bone grafts have been used in maxillofacial reconstruction. The ideal bone harvest site and grafting procedure remains a point of contention in regards to obtaining optimal long-term results with sufficient bone quantity and density without serious complications. More recently, confronted with growing patient requests and biomaterials development, maxillofacial surgeons and dentists have been considering these issues as they relate to pre-implant surgery. This study sought to evaluate implant success rate and complications following pre-implant surgery with parietal bone grafting. MATERIALS AND METHODS: A retrospective study was carried out on patients who underwent maxillofacial reconstruction of different sites (symphysis, mandibular corpus, maxillary sinus and premaxilla) for the purpose of implant insertion. RESULTS: 311 procedures in 211 patients were included. The implant osseointegration rate was around 95%. Clinical follow-up ranged from 10 months to 11 years. A secondary procedure was performed in 6.1% of cases and we noted no serious complications at the harvest site. DISCUSSION: With good revascularization and osseointegration of the graft, the use of parietal bone leads to an implant success rate similar to that seen in the literature. Moreover, the use of this material results in few infections and low bone resorption provided there is strict immobilization of the graft and no tension on the soft tissue sutures. CONCLUSION: Parietal bone grafts technique possess the required qualities for the success of implant surgery, offering results at least as interesting as others using autogenous bone and with no serious complications on donor site.

Differential expression of immunologic proteins in gingiva after socket preservation in mini pigs

During healing following tooth extraction, inflammation and the immune response within the extraction socket are related to bone resorption. Objective : We sought to identify how the alloplastic material used for socket preservation affects the immune responses and osteoclastic activity within extraction sockets. Material and Methods : Using a porcine model, we extracted teeth and grafted biphasic calcium phosphate into the extraction sockets. We then performed a peptide analysis with samples of gingival tissue from adjacent to the sockets and compared the extraction only (EO) and extraction with socket preservation (SP) groups. We also used real-time polymerase chain reaction (PCR) to evaluate the expression level of immunoglobulins, chemokines and other factors related to osteoclastogenesis. Differences between the groups were analyzed for statistical significance using paired t tests. Results : Levels of IgM, IgG and IGL expression were higher in the EO group than in the SP group 1 week post-extraction, as were the levels of CCL3, CCL5, CXCL2, IFN-γ and TNF-α expression (p<0.05). In addition, receptor activator of nuclear factor kappa-B ligand (RANKL) was also significantly upregulated in the EO group (p<0.05), as were IL-1β, IL-6 and IL-8 (p<0.05). Conclusions : These results suggest that the beneficial effect of socket preservation can be explained by suppression of immune responses and inflammation. .