Assessment of Somatosensory and Psychosocial Function of Patients With Trigeminal Nerve Damage.

OBJECTIVE: The present study assessed somatosensory changes related to trigeminal nerve damage using extensive evaluation tools and assessed the effect of such damage on the patients' psychosocial status and quality of life compared with healthy participants. METHODS: In 37 patients with intraorally or extraorally presenting trigeminal nerve damage diagnosed as painful or nonpainful posttraumatic trigeminal neuropathy, psychophysical tests like quantitative sensory testing (QST) and qualitative sensory testing and the electrophysiological "nociceptive-specific" blink reflex were performed. The patients and 20 healthy participants completed a set of questionnaires assessing their psychosocial status and quality of life. RESULTS: A loss or gain of somatosensory function was seen in at least 1 QST parameter in >88.9% of the patients. Patients in whom extraoral QST was performed showed an overall loss of somatosensory function, whereas intraoral QST showed a general gain of somatosensory function. Qualitative sensory testing identified a side-to-side difference in the tactile and pinprick stimulation in >77% of the patients. An abnormal "nociceptive-specific" blink reflex response was seen in 42.1% to 71.4% of patients dependent on the trigeminal branch stimulated, though comparisons with healthy reference values showed ambiguous results. Compared with the healthy participants, patients showed higher scores for pain catastrophizing, symptoms of depression and anxiety, limited jaw function, more somatic symptoms, and significantly impaired oral health-related quality of life (all P<0.038). DISCUSSION: The results from the present study showed presence of varied somatosensory abnormalities when assessed using psychophysical and electrophysiological investigations and a significantly impaired psychosocial status.

Soluble silica inhibits osteoclast formation and bone resorption in vitro.

Several studies have suggested that silicon (Si) may be essential for the normal development of connective tissue and the skeleton. Positive effects of Si from the diet as well as from Si-containing biomaterials, such as bioactive glass 45S5 (BG), have been demonstrated. Studies have reported that Si stimulates osteoblast proliferation and differentiation. However, the effects of Si on osteoclasts have not been directly addressed. The purpose of the present in vitro study was to clarify if Si has regulatory effects on osteoclast formation and bone resorption. The effects of BG, BG dissolution extracts and Si containing cell culture medium were investigated in a mouse calvarial bone resorption assay and osteoclast formation assays (mouse bone marrow cultures and RAW264.7 cell cultures). We conclude from our results that Si causes significant inhibition of osteoclast phenotypic gene expressions, osteoclast formation and bone resorption in vitro. In conclusion, the present study suggests that Si has a dual nature in bone metabolism with stimulatory effects on osteoblasts and inhibitory effects on osteoclasts. This suggested property of Si might be interesting to further explore in future biomaterials for treatments of bone defects in patients.

In vitro study of the biological interface of Bio-Oss: implications of the experimental setup.

OBJECTIVES: To systematically investigate the biological interface of Bio-Oss by analysing dissolution-precipitation behaviour and osteogenic responses using in vitro experimental systems. MATERIAL AND METHODS: Different concentrations (1-100 mg/ml) of Bio-Oss were incubated in cell culture medium for 24 h before elemental concentrations for calcium, phosphorus and silicon in the medium were analysed with inductive coupled plasma-optical emission spectroscopy. Radioactive calcium-45 isotope labelling technique was used to study possible precipitation of calcium on the Bio-Oss particle. Biological interface of Bio-Oss was studied in osteogenic experiments using mineralization medium and three different sources of cells (primary mouse bone marrow stromal cells, primary rat calvarial cells and MC3T3-E1 mouse pre-osteoblast cell line). Cells were fixed and stained with Toulidine blue, von Kossa or Alizarin Red staining for confirmation of extracellular matrix mineralization. RESULTS: Elemental analysis of the cell culture medium demonstrated a significant decrease of calcium and phosphorus and a dose-dependent release of silicon to the medium after incubation with Bio-Oss. A significant decrease of calcium and phosphorus in the medium occurred even at low concentrations of Bio-Oss. Uptake of calcium on the Bio-Oss particle was confirmed with radioactive calcium-45 isotope labelling technique. In osteogenic experiments with Bio-Oss (<1 mg/ml), matrix mineralization around the Bio-Oss particles were demonstrated in all three cell types with von Kossa and Alizarin Red staining. CONCLUSION: Dissolution-precipitation reactions occur at the surface of Bio-Oss, and osteogenic responses are seen at the biological interface. The concentration of Bio-Oss is a key factor for the experimental in vitro results, and may also have implications for the clinic.

Effects of Dyract AP and released ionic products on periodontal ligament cells and bone marrow cultures.

OBJECTIVES: The aim of this work was to investigate the release of inorganic ionic products from specimens of the polyacid-modified composite resin Dyract AP (DAP) and furthermore, to analyze the biological effect of DAP and the medium extract in human periodontal ligament (PDL) cells and mouse bone marrow cell (BMC) cultures. METHODS: Ion release from DAP specimens immersed in cell culture medium was analyzed with inductively coupled plasma optical emission spectroscopy (ICP-OES). Cells were cultured with either DAP specimens or with DAP media extract and effects on cell proliferation, osteoblastic gene expression and mineralization capacity were analyzed with direct-contact tests, neutral red (NR) uptake, quantitative real-time PCR and a bone nodule formation assay. RESULTS: ICP-OES analysis of DAP extract demonstrated a significant increase in fluoride, strontium and silica. PDL cells demonstrated normal growth pattern in the direct-contact tests with the material. DAP extracts produced a dose-dependent stimulation of cell proliferation and concomitant inhibition of osteoblast specific markers and nodule formation. SIGNIFICANCE: The compomer may have possible bioactive properties due to ions leaching out from the filler component.