The association of external cervical resorption with modern internal bleaching protocols: what is the current evidence?

Internal bleaching is an effective and minimally invasive way of bleaching non-vital teeth. A commonly cited risk associated with it is external cervical resorption (ECR), which is a potentially significant complication that could result in loss of the tooth. This is an important point of discussion with a patient during the consent process. Legally, patients are required to be made aware of material risks to which they would be likely to attach significance, such as the loss of a tooth. The risk of ECR is therefore a key component in the patient's decision-making process as they weigh it against the perceived benefits. Over the last ten years, both clinical and legal reasons have resulted in a number of changes in the materials and protocols used for internal bleaching. This leads to the question of what the current quality of evidence is regarding the association of ECR following internal bleaching with modern protocols. Other restorative options for discoloured teeth, such as veneers or crowns, involve the irreversible removal of tooth tissue and these may be chosen by patients over internal bleaching based on out-of-date evidence.

Dental implications of new oral anticoagulants for atrial fibrillation.

UNLABELLED: As dental professionals, we should all be familiar with the most common oral anticoagulant, warfarin, and how to manage our patients that are taking it. However, several new oral anticoagulants which have recently been approved by the National Institute for Health and Care Excellence (NICE) are now being prescribed for patients in the United Kingdom. These new oral anticoagulants fall into two different categories: a direct thrombin inhibitor dabigatran etexilate (Pradaxa Boehringer-Ingelheim, Bracknell, Berkshire) and activated Factor X inhibitors rivaroxaban (Xarelto Bayer HealthCare, Newbury, Berkshire) and apixaban (Eliquis Bristol-Myers Squibb, Uxbridge, Middlesex). These new drugs will have potential consequences for how dental practitioners manage patients requiring dental treatment, especially extractions and minor surgical procedures. CLINICAL RELEVANCE: It is important that dentists are aware of new anticoagulants which are being prescribed for patients to ensure that they receive safe and appropriate dental treatment. As healthcare professionals we should also be aware of how and when to report adverse drug reactions.

EM in high-dimensional spaces.

This paper considers fitting a mixture of Gaussians model to high-dimensional data in scenarios where there are fewer data samples than feature dimensions. Issues that arise when using principal component analysis (PCA) to represent Gaussian distributions inside Expectation-Maximization (EM) are addressed, and a practical algorithm results. Unlike other algorithms that have been proposed, this algorithm does not try to compress the data to fit low-dimensional models. Instead, it models Gaussian distributions in the (N - 1)-dimensional space spanned by the N data samples. We are able to show that this algorithm converges on data sets where low-dimensional techniques do not.