It was the aim of the present study to find out which radiological imaging techniques allow assessing the extent of bisphosphonate-associated osteonecrosis of the jaw (BONJ) in an adequate way. Twenty-four patients suffering from BONJ were included in the study. Before surgery, each patient was examined with panoramic radiograph, contrast-enhanced magnetic resonance imaging (MRI) and non-enhanced computed tomography. The detectability of BONJ was assessed for the three imaging techniques. The extent of the jaw region affected by BONJ was determined in MRI and CT scans and compared to the intra-operative situation. The detectability of BONJ lesions was 54% for panoramic radiographs, 92% for MRI scans and 96% for computed tomography (CT) scans. The intra-operatively assessed extent of BONJ correlated significantly with the measurements on CT scans (p = 0.0004) but did not correlate significantly with the measurements in MRI scans (p = 0.241). The intra-operatively measured extent of BONJ differed significantly from the CT measurements (p = 0.00003) but not from the MRI data (p = 0.137). Although MRI as well as CT have a high detectability for BONJ lesions that exceeds that of panoramic radiographs by far, both techniques show problems with the exact assessment of the extent of BONJ lesions in the individual patients. Therefore, the relevance of MRI and CT for the preoperative assessment of the extent of BONJ lesions is limited. Future research should focus on the identification of imaging techniques that allow assessing the extent of BONJ lesions with a higher accuracy.

The aim of the study was to assess the suitability of different Ti-6Al-4V surfaces produced by the electron beam melting (EBM) process as matrices for attachment, proliferation, and differentiation of human fetal osteoblasts (hFOB 1.19). Human osteoblasts were cultured in vitro on smooth and rough-textured Ti-6Al-4V alloy disks. By means of cell number and vitality and SEM micrographs cell attachment and proliferation were observed. The differentiation rate was examined by using quantitative real-time PCR analysis for the gene expression of alkaline phosphatase (ALP), type I collagen (Coll-I), bone sialoprotein (BSP) and osteocalcin (OC). After 3 days of incubation there was a significant higher vitality (p < 0.02) and proliferation (p < 0.02) of hFOB cells on smooth surfaces (R(a) = 0.077 microm) and compact surfaces with adherent partly molten titanium particles on the surface (R(a) /= 56.9 microm) reduced proliferation of hFOB cells. Surface characteristics of titanium can easily be changed by EBM in order to further improve proliferation.

It was the aim of the study to assess differences in patient morbidity between transmucosal implant placement and implant installation after elevation of mucoperiosteal flaps. In five of the patients, implants were placed in the maxilla transmucosally using a CAD/CAM surgical template [test group (TG)]. In the remaining five patients, the implants were installed after the elevation of mucoperiosteal flaps [control group (CG)]. Directly after surgery, at days 1 and 7 after surgery the patients rated pain and discomfort on a visual analogue scale (0=minimal pain and discomfort, 100=maximal pain and discomfort). Optical three-dimensional images were assessed preoperatively and at days 1 and 7 after surgery to determine the visible soft tissue swelling of the upper lip and cheeks. Directly postoperatively, the mean pairwise difference between both groups in view of pain and discomfort ratings (control minus test) was 45.6 (SD, 20.7). At days 1 and 7, the mean differences were 51.6 (SD, 21.8) and 19 (SD, 8), respectively. The overall test of the area under curve (AUC) against the null hypothesis 'AUC of pairwise differences of pain score over study time equals null' yielded a significant difference (P=0.01). The mean pairwise difference between both groups in view of soft tissue volume increase was 6.1 (SD, 2) cm(3) at day 1 after surgery and 4.6 (SD, 1.2) cm(3) at day 7. The overall test of the AUC against the null hypothesis 'AUC of pairwise differences of oedema measurements over study time equals null' yielded a significant difference (P=0.002). Within the limitations of this pilot study, it could be shown that transmucosal implant placement reduces patient morbidity significantly compared with an open approach.

Due to the high success rate of osteotomy and primary wound closure, it should be checked for every patient suffering from BONJ if osteotomy is a viable treatment option.

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