A method for investigating the cellular response to cyclic tension or compression in three-dimensional culture.

We have an interest in the cellular response to mechanical stimuli, and here describe an in-vitro method to examine the response of cells cultured in a three-dimensional matrix to mechanical compressive and tensile stress. Synthetic aliphatic polyester scaffolds coated with 45S5 bioactive glass were seeded with human dental follicular cells (HDFC), and attached to well inserts and magnetic endplates in six well palates. Scaffolds were subjected to either cyclic 10% tensile deformation, or 8% compression, at 1 Hz and 2 Hz respectively for 6, 24 or 48 h, by uniaxial motion of magnetically-coupled endplates. It was possible to isolate high quality mRNA from cells in these scaffolds, as demonstrated by high RNA integrity numbers scores, and ability to perform meaningful cRNA microarray analysis, in which 669 and 727 genes were consistently upregulated, and 662 and 518 genes down regulated at all times studied under tensile and compressive loading conditions respectively. MetaCore analysis revealed the most regulated gene ontogenies under both loading conditions to be for: cytoskeletal remodelling; cell adhesion-chemokines and adhesion; cytoskeleton remodelling-TGF WNT and cytoskeletal remodelling pathways. We believe the method here described will be of value for analysis of the cellular response to cyclic loading.

Patients presenting to the general practitioner with pain of dental origin.

Dentofacial pain is a common presentation in general practice, and more than 50% of cases arise from dentally related pathology. In a carious tooth, pain that is site-specific, severe and spontaneous usually denotes extension of caries into the tooth pulp. Caries does not always appear as a cavity in the tooth, but may lie beneath intact enamel or on surfaces between teeth. Examination of tooth pain should include firm percussion (eg, with a tongue depressor). Tenderness on percussion denotes progression of infection into the subdental tissue. Pain occurring 24-48 hours after a tooth extraction is commonly caused by superficial osteitis in the exposed alveolar bone. Examination will reveal the absence of a blood clot in the extraction socket and severe tenderness on local palpation. Severe pain related to impacted wisdom teeth is frequently caused by pericoronitis, an infection in the gingival tissues surrounding the tooth. The surrounding gingiva is erythematous and tender to palpation. Localised facial swellings of dental origin require immediate referral to a dentist. Progressive facial swelling requires aggressive antibiotic therapy and referral to hospital for definitive management.