Resin-based composite (RBC) materials are increasingly being used for the restoration of posterior teeth. The increasing demand for aesthetic, tooth-coloured restorations coupled with the patient's concerns regarding the use of mercury containing restorations, has driven a surge in the use of RBC materials. With the Minamata Convention in 2013 calling for the phase-out of dental amalgam and dental schools increasingly teaching techniques for RBC restorations in posterior teeth, it is likely that the dental profession's reliance upon RBC for the restoration of posterior teeth will only increase. In order to simplify and speed-up the placement of large posterior RBCs, manufacturers have produced a range of materials which can be placed in single or deeper increments, known as bulk-fill RBCs. Over a relatively short period of time many bulk-fill RBCs have been marketed quoting increment depths between 4-10 mm. The placement of these larger increments of RBC may reduce the time needed when placing posterior restorations and thereby reduce technique sensitivity. This article aims to review the properties and handling characteristics of the bulk-fill RBC materials currently available, while advising the optimal techniques of placement.

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Background: Bonded retainers are widely used to maintain the positions of anterior teeth after orthodontic treatment. Various types of bonded retainer exist however, there is a lack of evidence to indicate which type is superior. Aim: To compare upper and lower CAD/CAM nitinol bonded retainers (Memotain®) with upper and lower chairside rectangular-chain bonded retainers (Ortho-FlexTech™), in terms of stability, retainer failures and patient satisfaction. Trial design: Multi-centre, two-arm, parallel-group, randomised controlled clinical trial with 1:1 allocation. Setting: Three trial centres: University Teaching Hospital; District General Hospital; and Specialist Orthodontic Practice. All treatment was provided free as part of a state-funded healthcare system. Materials and methods: A total of 68 patients were randomly allocated to receive either upper and lower Memotain® bonded retainers or upper and lower Ortho-FlexTech™ bonded retainers. Ten trained operators placed and reviewed the bonded retainers. Measurements were carried out on study models taken at debond and after six months. Patient satisfaction questionnaires were completed at six months following debond. Results: The trial was terminated due to the high number of failures (50%) of the upper Memotain® retainers within six months. Memotain® retainers were three times more likely to fail (unadjusted hazard ratio = 2.82, 95% confidence interval = 1.00-7.99) than Ortho-FlexTech™ retainers at six months in the upper arch. Patients were satisfied with both types of retainer. Limitations: Early termination of the trial means that the a priori sample size was not reached, so outcomes should be interpreted with caution. Conclusion: The trial was terminated early due to the high failure rate of upper Memotain® bonded retainers. They had a higher risk of failure in the maxillary arch when compared to upper Ortho-FlexTech™ bonded retainers after six months.

HighlightsThis case reports the first case to our knowledge of pathological fracture of the coronoid process of the mandible secondary to long term use of alendronic acid.Demonstrates the unpredictable nature of symptoms associated with medication related osteonecrosis and its management within the hospital environment.Demonstrates the rapidly progressing and unpredictable nature of the spread of the necrotic process in medication related osteonecrosis.Clear clinical photographs of the surgical procedure involved in the removal of necrotic bone and curettage of the surgical site in medication related osteonecrosis.

Aim: To discuss the past and present evidence for the coronectomy technique for third molars. Materials and Methods: A review of the past and present literature related to the healing of extraction sockets in the presence of root fragments. Results: High-quality research studies surrounding the coronectomy procedure are lacking and it is important therefore that surgeons are aware that change of practice is not yet supported. The long-term consequences, in terms of infection or other, are not known as study follow-up is short. Conclusion: If coronectomy is to be considered then the authors would suggest that this is only for patients at high risk of potential nerve injury and that the patient is made aware of the risk of failure, the possible need for re-operation and our lack of knowledge of long-term consequences. HistoryExperiments relating to the healing of extraction sockets in the presence of root fragments date as far back as 1924 1 . This marked a peak in interest in Germany and many experiments were carried out to assess healing of post-extraction wounds in the presence of root fragments 2-4 . These were non-clinical animal studies and related to reimplantation of root fragments rather than post-extraction retained root fragments per se. Although at the time this had no effect on the management of retained roots, it created interest concerning what happens to root fragments that are reimplanted within the mandible and maxilla.The first known data collected in reference to retention of root fragments, rather than reimplantation, were in 1947, where the healing of extraction sockets in the presence of retained root fragments was assessed histologically in rats 5 . This experiment demonstrated for the first time that root remnants deep within a wound may be tolerated by the adjacent tissues and retained without symptoms. Furthermore, the retained root fragments may go on to be covered by a cementum-like peripheral layer, also suggested previously by others in the literature 6,7 .The period 1974-1976 marked a further surge in interest with regard to root retention with a focus on preservation of the alveolar ridge 8 . It was shown for the first time in monkeys that vital submerged roots which were traumatically amputated, exposed to transient bacterial invasion and covered primarily, were free of any type of inflammatory infiltrate 9 . The same experiment showed that gutta-perchafilled roots submerged in the same way were associated with a mild pericoronal inflammatory response. The technique of reducing vital roots by 2 mm below the alveolar crest bone and suturing to cover the root surfaces was described in an animal study in 1976, and showed histologically that: • Roots retained a vital pulp. • Cementum covered the cut dentine. • Periodontal membrane covered the buried roots 10 .