Effect of endothelial cells on bone regeneration using poly(L-lactide-co-1,5-dioxepan-2-one) scaffolds.

Our recent in vitro study demonstrated that endothelial cells (ECs) might influence the differentiation of bone marrow stromal cells (BMSCs). Therefore, the aim of this study was to describe this effect in vivo, using a rat calvarial bone defect model. BMSCs were isolated from femurs of two-donor Lewis rats and expanded in α-minimum essential medium containing 10% fetal bovine serum. One fifth of BMSCs were induced and differentiated into ECs in an Endothelial Cell Growth Medium-2 and then characterized by a flow cytometry. The remaining BMSCs were cultured in freshly prepared osteogenic stimulatory medium, containing dexamethasone, ascorbic acid and ß-glycerophosphate. Either BMSCs alone (BMSC-group) or co-cultured ECs/BMSCs (CO-group) were seeded into poly(L-lactide-co-1,5-dioxepan-2-one) [poly(LLA-co-DXO)] scaffolds, cultured in spinner flasks, and then implanted into symmetrical calvarial defects prepared in recipient rats. The animals were sacrificed after 2 months. The formation of new bone was evaluated by radiography and histology and by the expression of osteogenic markers using reverse transcriptase-polymerized chain reaction (RT-PCR). To investigate vessel formation, histological staining was performed with EC's markers. The radiographical and histological results showed more rapid bone formation in the CO- than in the BMSC-group. However, the expression of EC's marker was similar on both groups by histological analysis after 2 months postoperatively. Furthermore, the CO-group exhibited greater expression of osteogenic markers as demonstrated by RT-PCR. The results are consistent with the previous in vitro findings that poly(LLA-co-DXO) scaffold might be suitable candidate for bone tissue engineering. In vivo, bone regeneration was enhanced by a construct of the polymer scaffold loaded with co-cultured cells.

Oral infections and their influence on medical rehabilitation in kidney transplant patients.

Infections seem to be the most common life-threatening complication of long-term immunosuppressive therapy following organ transplantation. Although sparse scientific evidence, potential oral infections are considered to contribute to these complications. The aim of this study was to examine whether there is an association between oral infections and rejections after kidney transplantation. A group of 46 kidney transplant candidates was enrolled. The patients were examined clinically and radiographically for dental caries, periodontal disease, mucosal lesions/infections, and general oral health problems. Examinations were conducted the day before transplantation, and one year post transplantation. Fifteen (32.6%) patients developed acute rejections during the first year. Six of these patients (40%) presented with oral opportunistic infections (candida or herpes infections of the oral mucosa). The number of dental infections and semi-impacted teeth were low. When rejections were related to probing pocket depths (PPDs) > or = 4 mm and apical lesions together, statistical significance was not reached (p=0.075, OR=3.17 [0.87; 11.55]). Similar results were obtained when PPDs > or = 4 mm, apical lesions, semi-impacted teeth, and opportunistic mucosal infections were compared to rejections. The results of the present study do not support that opportunistic oral mucosal infections or dental-related infections seem to increase the risk of rejection in kidney transplanted patients.

Short-term clinical and microbiologic effects of pocket debridement with an Er:YAG laser during periodontal maintenance.

BACKGROUND: The erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser is considered a useful tool for subgingival debridement because the laser treatment creates minimal damage to the root surface and has potential antimicrobial effects. The aim of this randomized controlled clinical trial was to evaluate clinical and microbiologic effects of pocket debridement using an Er:YAG laser in patients during periodontal maintenance. METHODS: Twenty patients at a recall visit for maintenance were consecutively recruited if presenting at least four teeth with residual probing depth (PD) > or = 5 mm. Two pockets in each of two jaw quadrants were randomly assigned to subgingival debridement using 1) an Er:YAG laser (test) or 2) an ultrasonic scaler (control). The laser beam was set at 160 mJ with a pulse frequency of 10 Hz. Clinical variables were recorded at baseline, 1 month, and 4 months after treatment. Primary clinical outcome variables were changes in PD and clinical attachment level (CAL). Microbiologic analysis of subgingival samples was performed at baseline, 2 days, and 30 days after treatment using a checkerboard DNA-DNA hybridization technique against 12 periodontal disease-associated species. RESULTS: The mean initial PD was 6.0 mm (SD: 1.2) in the test group and 5.8 mm (SD: 0.9) in the control group. At 1 month post-treatment, the PD reduction was significantly greater for test than control sites (0.9 versus 0.5 mm; P <0.05). The CAL gain also was significantly greater (0.5 versus 0.06 mm; P <0.01). At the 4-month examination, no significant differences were detected in PD reduction (1.1 versus 1.0 mm) or CAL gain (0.6 versus 0.4 mm). Both treatments resulted in reduction of the subgingival microflora. No significant differences in microbiologic composition were identified between the treatment groups at various time intervals. Degree of treatment discomfort scored significantly lower for the test than the control treatment modality. CONCLUSION: The results of the trial failed to demonstrate any apparent advantage of using an Er:YAG laser for subgingival debridement, except less treatment discomfort perceived by the patients.