Effect of magnesium sulphate added to lidocaine on inferior alveolar nerve block success in patients with symptoms of irreversible pulpitis: a prospective, randomized clinical trial.

AIM: To investigate the effect of magnesium sulphate used as an adjuvant to lidocaine with epinephrine local anaesthetic on the success of inferior alveolar nerve blocks (IANB) in patients with symptoms of irreversible pulpitis undergoing root canal treatment. METHODOLOGY: In a double-blind clinical trial, following power calculation, 124 patients with symptoms of irreversible pulpitis in mandibular molar teeth were selected, and initial pain data were collected using a Heft-Parker (Pain, 19, 1984 and 153) visual analogue scale. The first group (control) received IANB with 1.8 mL of a local anaesthetic solution containing 1.8% lidocaine with 1 : 88 000 epinephrine while the second group (test) received IANB with 1.8 mL of an anaesthetic solution containing 1% magnesium sulphate, and 1.8% lidocaine with 1 : 88 000 epinephrine. Pain data were collected after access cavity and penetration of files in the canals using a Heft-Parker visual analogue scale. Two patients were not included in the study as they did not consent, and a further 54 patients were excluded as they did not report lip numbness within 15 min after IANB administration; thus, the data presented in this study are related to 68 patients. The data were analysed using chi-square and t-test (α = 0.05). RESULTS: The success of pulpal anaesthesia with IANB was 82% for the magnesium sulphate group and 53% for the control group. There was a significant difference in the effectiveness of the IANB between the two groups (P < 0.001). There was no significant difference between the magnesium sulphate and control groups regarding gender (P = 0.598) or age (P = 0.208) or initial pain scores (P = 0.431). CONCLUSIONS: The addition of 1% magnesium sulphate to 1.8% lidocaine with 1 : 88 000 epinephrine resulted in a positive impact for the success of IANB in patients with a diagnosis of irreversible pulpitis related to mandibular molar teeth undergoing root canal treatment. Thus magnesium sulphate may be used as adjuvant for achieving profound pulpal anaesthesia in challenging cases. However, more studies with larger sample size and different concentration doses must be carried out to establish an appropriate conclusion before its routine clinical use.

Analysing the bioactive makeup of demineralised dentine matrix on bone marrow mesenchymal stem cells for enhanced bone repair.

Dentine matrix has proposed roles for directing mineralised tissue repair in dentine and bone; however, the range of bioactive components in dentine and specific biological effects on bone-derived mesenchymal stem cells (MSCs) in humans are less well understood. The aims of this study were to further elucidate the biological response of MSCs to demineralised dentine matrix (DDM) in enhancing wound repair responses and ascertain key contributing components. Dentine was obtained from human teeth and DDM proteins solubilised with ethylenediaminetetraacetic acid (EDTA). Bone marrow derived MSCs were commercially obtained. Cells with a more immature phenotype were then selected by preferential fibronectin adhesion (FN-BMMSCs) for use in subsequent in vitro assays. DDM at 10 µg/mL reduced cell expansion, attenuated apoptosis and was the minimal concentration capable of inducing osteoblastic differentiation. Enzyme-linked immunosorbent assay (ELISA) quantification of growth factors indicated physiological levels produced the above responses; transforming growth factor ß (TGF-ß1) was predominant (15.6 ng/mg DDM), with relatively lower concentrations of BMP-2, FGF, VEGF and PDGF (6.2-4.7 ng/mg DDM). Fractionation of growth factors from other DDM components by heparin affinity chromatography diminished osteogenic responses. Depletion of biglycan from DDM also attenuated osteogenic potency, which was partially rescued by the isolated biglycan. Decorin depletion from DDM had no influence on osteogenic potency. Collectively, these results demonstrate the potential of DDM for the delivery of physiological levels of growth factors for bone repair processes, and substantiate a role for biglycan as an additional adjuvant for driving osteogenic pathways.

Growth Factor Liberation and DPSC Response Following Dentine Conditioning.

Liberation of the sequestrated bioactive molecules from dentine by the action of applied dental materials has been proposed as an important mechanism in inducing a dentinogenic response in teeth with viable pulps. Although adhesive restorations and dentine-bonding procedures are routinely practiced, clinical protocols to improve pulp protection and dentine regeneration are not currently driven by biological knowledge. This study investigated the effect of dentine (powder and slice) conditioning by etchants/conditioners relevant to adhesive restorative systems on growth factor solubilization and odontoblast-like cell differentiation of human dental pulp progenitor cells (DPSCs). The agents included ethylenediaminetetraacetic acid (EDTA; 10%, pH 7.2), phosphoric acid (37%, pH <1), citric acid (10%, pH 1.5), and polyacrylic acid (25%, pH 3.9). Growth factors were detected in dentine matrix extracts drawn by EDTA, phosphoric acid, and citric acid from powdered dentine. The dentine matrix extracts were shown to be bioactive, capable of stimulating odontogenic/osteogenic differentiation as observed by gene expression and phenotypic changes in DPSCs cultured in monolayer on plastic. Polyacrylic acid failed to solubilize proteins from powdered dentine and was therefore considered ineffective in triggering a growth factor-mediated response in cells. The study went on to investigate the effect of conditioning dentine slices on growth factor liberation and DPSC behavior. Conditioning by EDTA, phosphoric acid, and citric acid exposed growth factors on dentine and triggered an upregulation in genes associated with mineralized differentiation, osteopontin, and alkaline phosphatase in DPSCs cultured on dentine. The cells demonstrated odontoblast-like appearances with elongated bodies and long extracellular processes extending on dentine surface. However, phosphoric acid-treated dentine appeared strikingly less populated with cells, suggesting a detrimental impact on cell attachment and growth when conditioning by this agent. These findings take crucial steps in informing clinical practice on dentine-conditioning protocols as far as treatment of operatively exposed dentine in teeth with vital pulps is concerned.