Effectiveness of arginine-containing toothpastes in treating dentine hypersensitivity: A systematic review

Objectives

To evaluate by way of a systematic review the effectiveness of arginine-containing desensitising toothpastes in comparison to control agents in reducing dentine hypersensitivity.

Data sources

Electronic databases were searched including: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS (30/03/2012). Reference lists of eligible studies and systematic reviews were cross-checked in an attempt to identify additional studies. Strategies to identify grey literature were employed.

Study selection inclusion criteria

Controlled Clinical Trials (CCTs) and Randomised Controlled Trials (RCTs) comparing arginine-containing desensitising toothpastes to non-arginine-containing control toothpastes.Two review authors independently screened the titles and abstracts of studies identified. Data collection forms were completed for included studies.

Outcomes

Changes in sensitivity to tactile and air-blast stimuli. A subjective assessment of sensitivity was also sought.

Conclusion

Data identified indicates a potential role for arginine-containing toothpastes in managing dentine hypersensitivity. However, this conclusion is based on small sample sizes and the studies identified did not follow patients up in the medium to long term. The authors recommend that there is a need for well-designed RCTs to be conducted prior to any definitive recommendations being made.

Clinical significance

Dentine hypersensitivity is a common condition. Its multi-factorial aetiology has led to several treatment modalities being advocated. The continued introduction of new desensitising agents suggests that no product has yet proven ultimately successful. Arginine-containing toothpastes have recently been introduced, this article systematically reviews the evidence relating to their effectiveness.     

Inter-ictal assay of peripheral circulating inflammatory mediators in migraine patients under adjunctive cervical non-invasive vagus nerve stimulation (nVNS): A proof-of-concept study

Objective

To assay peripheral inter-ictal cytokine serum levels and possible relations with non-invasive vagus nerve stimulation (nVNS) responsiveness in migraineurs.

Potentiation of sympathetic neuromuscular transmission mediated by muscarinic receptors in guinea pig isolated vas deferens

In guinea-pig isolated vasa deferentia, purinergic neurogenic contractions and responses to applied adenosine 5-triphosphate (ATP) were potentiated by carbachol; responses to adrenergic transmission and applied noradrenaline were not. Following blockade of P2 receptors and -adrenoceptors, the residual neurogenic response was massively potentiated by carbachol, suggesting the presence of a non-purinergic, non-adrenergic component. In the presence of guanethidine, carbachol had no significant effect, indicating that sympathetic transmission was the only element involved. Use of oxotremorine and selective muscarinic receptor antagonists suggested that the potentiating effect of carbachol and oxotremorine was mediated via M3 muscarinic receptors without involvement of nicotinic receptors.     

Allopregnanolone treatment, both as a single injection or repetitively, delays demyelination and enhances survival of Niemann-Pick C mice

Niemann-Pick C disease (NPC) is an irreversible neurodegenerative disorder without current treatment. It is thought to result from deficient intracellular cholesterol and/or ganglioside trafficking. We have investigated the effects of allopregnanolone treatments on survival, weight loss, motor function, magnetic resonance imaging (MRI), and neuropathology in the mouse model of NPC (Npc1(-/-) mice). We confirmed previous results showing that a single injection of 250 microg of allopregnanolone on postnatal day 7 significantly extended the life span of Npc1(-/-) mice. This caused a marked difference in the weight curves of the treated mice but no statistical difference in the Rota-Rod performance. T2-weighted MRI and diffusion tensor imaging (DTI) of treated mice showed values of signal intensity and fractional anisotropy closer to those of wild-type mice than those of untreated Npc1(-/-) mice. Neuropathology showed that day-7 treatment markedly suppressed astrocyte reaction and significantly reduced microglial activation. Furthermore, the steroid treatment also increased myelination in brains of Npc1(-/-) mice. Similar effects of allopregnanolone treatment were observed in Npc1(-/-), mdr1a(-/-) double-mutant mice, which have a deficient blood-brain barrier, resulting in increased steroid uptake. The effects on survival and weight loss of a single injection on day 7 followed by injections every 2 weeks were also evaluated in Npc1(-/-) mice, and the beneficial effects were found to be greater than with the single injection at day 7. We conclude that allopregnanolone treatment significantly ameliorates several symptoms of NPC in Npc1(-/-) mice, presumably by effects on myelination or neuronal connectivity.     

Cholinergic modulation of the urethro genital reflex in spinal cord-transected rats

The aim of this study was to determine which of the muscarinic receptor subtypes are involved in the modulation of the urethrogenital reflex (UGR) in male, spinal cord-transected rats. The electromyographic (EMG) responses of the bulbospongiosus muscle (BS) to the topical spinal application of muscarine and the combination of muscarine and the selective muscarine receptor antagonists methoctramine (M2), AFDX (M2), 4DAMP (M3) and tropicamide (M4) were determined before and after the elicitation of UGR by way of the mechanical stimulation of the urethra. When 50- and 100-mug doses of muscarine were applied without urethral stimulation, a rhythmic activity of the BS was observed, similar to the one found when UGR was evoked. The M3 and M4 - but not the M2 - antagonists prevented BS response to muscarine when urethral stimulation was not performed. When UGR was elicited following urethral stimulation muscarine produced an increase in burst duration and a decrease in burst frequency. The M2 antagonist reverted the effects of muscarine on the UGR, while the M3 and M4 antagonists produced a significant increase in the frequency and in the bursts number, when compared to the control muscarine response. The differences observed in BS responses to muscarine and muscarine antagonists before and after UGR elicitation were probably linked to the intrinsic effects of the endogenous acethylcholine (Ach) released after urethral stimulation. The present results suggest a cholinergic modulation of UGR in spinal cord-transected rats mediated by the M2, M3 and M4 muscarinic receptor subtypes.