Karl Andreas Schlegel

The study was designed to detect disseminated tumor cells (DTCs) in postoperative peripheral blood of patients with oral squamous cell carcinoma (OSCC) and to determine their relevance as prognostic markers by cytokeratin (CK) expression analysis. Forty samples of peripheral blood mononuclear cells (PBMCs) isolated 4 weeks after surgery were screened for occurrence of four CK mRNA transcripts by real-time quantitative RT qPCR. Detection of mRNA expression was compared with clinicopathological parameters and disease-free survival (DFS). CK 17 and CK 19 could not be detected in any samples. CK 18 and CK 20 were detectable in 1 (2.5%) and in 14 (35.0%), respectively. The detection of CK 20 was not significantly associated with lymph node status, clinical stage, or differentiation grade, but was significantly higher in patients with T3 and T4 OSCC (p = 0.04). DFS was not associated with tumor size, clinical stage, or differentiation grade. But poor DFS was significantly associated with the occurrence of lymph node metastasis (p = 0.01) and detection of CK 20 (p = 0.01). DTCs in PBMCs of postoperative patients with OSCC could only be detected by determination of CK 20 mRNA. Detection of CK 20 mRNA in peripheral blood seems to be of relevance for prognosis in OSCC.

Osseointegration of implants depends on time and the local bone conditions regarding quality and quantity. This led to the bone classification by Lekholm and Zarb. The aim of the present study was to enhance osseointegration of implants through conditioning of the bone bed and to compare in this context the efficacy of bone condensation, an osteoinductive collagen (Colloss), and platelet-rich plasma (PRP). Porcine frontal skull bone was used for the preparation of Identical-size implant beds. Before placement of the implants (Ankylos, 3.5 x 4 mm), the implant beds were untreated (control) or conditioned with condensation, Colloss, or PRP. The animals were sacrificed after 2, 4, and 8 weeks. The specimens were then compared and analyzed by microradiography, and statistical analysis was performed using the Wilcoxon signed rank test. At the early observation times, significant effects on the sites of topical bone conditioning in comparison to the control group could be seen regarding the implant-bone interface (2 weeks: control 31%, Colloss 60%, condensation 73%, PRP 47%; 4 weeks: control 39%, Colloss 51%, condensation 40%, PRP 42%) and peri-implant bone density (2 weeks: control 31%, Colloss 48%, condensation 59%, PRP 39%; 4 weeks: control 47%, Colloss 53%, condensation 41%, PRP 50%). A leveling of the results between groups was found at 8 weeks (implant-bone interface: control 51%, Colloss 58%, condensation 55%, PRP 62%; peri-implant bone density: control 50%, Colloss 55%, condensation 51%, PRP 51%). Overall, bone condensation and Colloss apparently influenced bone formation process from the onset, but over the entire 8-week healing period, differences in bone formation were not significant It can be stated that, in the initial healing phase, an effect of topical bone conditioning may be achieved by the different described methods.

The aim of this study was to compare a bovine bone substitute (Bio-Oss) to autogenous bone with respect to its value as a material for sinus augmentation. In 10 beagle dogs 12 months of age, the 3 maxillary premolars were extracted on both sides. Six weeks later, 2 cavities of predefined size were produced in the region of the nasal cavity. The antral window was 25 mm long and had a vertical extension of 7 mm. Two Frialit-2 implants (3 x 8 mm) were placed in each bone defect (n = 20). Every implant was primarily stable because of fixation in native bone. In each maxilla, 1 bone defect was filled with autogenous bone harvested from the mandible and 1 was filled with Bio-Oss (material selected at random). The animals were sacrificed at 90 and 180 days, and histologic specimens were examined and the results subjected to statistical analysis by the Wilcoxon test for paired observations. No healing problems were observed. Histologically, after 90 days the volume of the augmentation showed a reduction of 14.6 +/- 4.4% within the Bio-Oss group and 3.8 +/- 2.5% in the group with autogenous bone. Bone-implant contact of 52.16 +/- 13.15% in the Bio-Oss group and 60.21 +/- 11.46% in the autogenous bone group was observed. At 180 days, the Bio-Oss group showed bony ingrowth of the substitute, whereas in the autogenous group a differentiation from original bone could no longer be made. The volume reduction was 16.5 +/- 8.67% in the Bio-Oss group and 39.8 +/- 16.14% in the autogenous group. Bone-implant contact of 63.43 +/- 19.56% in the Bio-Oss group and 42.22 +/- 12.80% in the autogenous bone group was measured. The results indicated that because of the nonresorptive properties of the bone substitute Bio-Oss, regeneration of the defects is achievable. It was demonstrated that the bone substitute seemed to behave as a permanent implant. The volume of the area augmented by autogenous bone decreased over the observation period.