The inverted periosteal graft

The adult human periosteum is known to contain fibroblasts and their progenitor cells, osteoblasts and their progenitor cells, and stem cells. In all age groups, the cells of the periosteum retain the ability to differentiate into fibroblasts, osteoblasts, chondrocytes, adipocytes, and skeletal myocytes. The tissues produced by these cells include cementum with periodontal ligament fibers and bone. The inverted periosteal graft is designed to place multipotent cells in the periodontal lesion with the ability to regenerate cementum, periodontal ligament, and bone.     

Secondary caries-like lesions at fissure sealings with Xeno III and Delton--an in vitro study

OBJECTIVES: The aim of the study was to establish a bacterial based in vitro caries model to test the caries preventive effect of fissure sealants and to investigate whether a self-etching adhesive (Xeno III) used as fissure sealant is equally effective in preventing secondary caries compared to a conventional sealant (Delton) when applied on saliva contaminated and non-contaminated fissures. METHODS: Forty caries-free upper premolars were randomly divided into two groups. Group A was sealed with a conventional resin-based fissure sealant (Delton) after phosphoric acid etching. Group B was sealed with a self-etching adhesive (Xeno III) without prior etching. To simulate the clinical situation of saliva contamination, the distal part of each tooth was slightly moistened with saliva before sealant application. After thermo-cycling, the specimens were exposed to a cariogenic Streptococcus mutans biofilm in an artificial mouth model. Depths of demineralization were measured on serial sections by confocal laser scanning microscopy. If a demineralization was detected underneath the whole fissure sealing the sample was rated as 'total failure'. RESULTS: Significantly higher numbers of total failures could be found in the Xeno III group compared to the Delton group in areas without saliva contamination. On contaminated areas, no significant difference could be found. There was no significant difference regarding the depth of the primary carious lesions between groups. CONCLUSION: The study supports our recent findings that our caries model is capable to produce secondary caries-like lesions at fissure sealings. Based on the present in vitro data, it cannot be recommended to use the self-etching adhesive Xeno III solely as a fissure sealant.     

The surface roughness of restorative materials and dental tissues after polishing with prophylaxis and polishing pastes

The effect of prophylaxis and polishing pastes on bovine tooth hard tissues and dental materials was investigated in vitro. Four restorative dental materials (gold, amalgam, a conventional composite, a microfilled composite), brought to a standard surface finish, and two bovine dental hard tissues (enamel, dentin) were polished with ten different prophylaxis and polishing pastes. Before polishing, SEM photographs were taken of all materials, and surface profiles were obtained of every sample. After polishing, surface profiles from every sample and SEM photographs of every material/paste combination were obtained. Using the same techniques, two-step polishing procedures were also investigated. The evaluation of the surface profiles and the rated SEM photographs (by 20 dentists) showed significant paste and material differences. There was a significant correlation (0.82) between the results of the surface profiles and the SEM ratings. Almost all pastes roughened the surfaces of dental restorative materials and only a few pastes showed a tendency to render the surfaces of dental restorative materials and only a few paste showed a tendency to render the surfaces of dental hard tissues smoother. Therefore, if polishing is indicated after periodontal treatment, the paste used should be selected carefully. Since the surface roughness of conventional composites increases tremendously during each polishing with pastes, their surfaces should be avoided when using polishing pastes. If polishing with a paste in indicated, conventional composites should be polished afterwards with aluminium silicate coated discs.