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Bruxism is unlikely to be a risk factor for biological complications around dental implants, while there are some suggestions that it may be a risk factor for mechanical complications.

Objective In this investigation, the precision of a commercial three-dimensional digitizer in the detection of facial landmarks in human adults was assessed. Methods Fifty landmarks were identified and marked on the faces of five men, on five women, and on a stone cast of the face of one man. For each subject, the three-dimensional coordinates of the landmarks were obtained twice using an electromagnetic three-dimensional digitizer, and the duplicate digitizations were superimposed using common orientations and centers of gravity. Metric differences between homologous landmarks were assessed, and Dahlberg's error was computed. Results For both men and women, the error was 1.05% of the nasion-mid-tragion distance, while for the cast, it was 0.9%. When the duplicate digitizations were used to mathematically reconstruct the faces, and several distances, angles, volumes, and surfaces were computed, more than 80% of the measurements had coefficients of variation lower than 1%. Conclusions The digitizer can assess the coordinates of facial landmarks with sufficient precision, and reliable measurements can be obtained.

M etal-free materials compared with metal-ceramic or other conventional all-metal materials for prosthodontic restorations Patient or population: adults (18 years of age or older) with prosthodontic restorations Settings: prim ary or secondary care Intervention: m etal-f ree m aterials Comparison: m etal-ceram ic or other conventional all-m etal m aterials This review is m ade up alm ost entirely of single-study com parisons of very sm all studies. For each com parison, the evidence f or the prim ary outcom es 'f ailure of the prosthesis', 'com plications' and 'aesthetic evaluation' at all tim es of assessm ent was rated as being very low quality. All bodies of evidence were downgraded by 1 level f or risk of bias and by 2 levels f or im precision (due to single-study com parisons with either very sm all sam ple sizes, low event rates, 95% CIs including the possibility of benef it f or both the test and control groups, or com binations of these problem s) This review has included studies assessing the f ollowing com parisons 1) M etal-f ree single crowns com pared to conventional crowns 2) M etal-f ree FDPs com pared to m etal-ceram ic FDPs 3) M etal-f ree cantilevered FDPs com pared to m etal-ceram ic cantilevered FDPs 4) M etal-f ree im plant-supported single crowns com pared to m etal-ceram ic im plant-supported single crowns 5) M etal-f ree abutm ents com pared to m etal abutm ents supporting single crowns 6) M etal-f ree im plant-supported FDPs m ade of dif f erent m aterials 7) M etal-f ree tooth-supported FDPs m ade of dif f erent m aterials CI: conf idence interval; FDPs: f ixed dental prostheses. GRADE Working Group grades of evidence High quality: f urther research is very unlikely to change our conf idence in the estim ate of ef f ect M oderate quality: f urther research is likely to have an im portant im pact on our conf idence in the estim ate of ef f ect and m ay change the estim ate Low quality: f urther research is very likely to have an im portant im pact on our conf idence in the estim ate of ef f ect and is likely to change the estim ate Very low quality: we are very uncertain about the estim ate B A C K G R O U N D Description of the condition Missing or severely damaged teeth may result in a functional and aesthetic deficit and have traditionally been replaced with fixed prosthodontic treatment (crowns or bridges). 4 Metal-free materials for fixed prosthodontic restorations (Review)

This study systematically reviews the sleep bruxism (SB) literature published in the MEDLINE and Scopus databases to answer the following question: What is the validity of the different portable instrumental devices that have been proposed to measure SB if compared with polysomnographic (PSG) recordings assumed as the gold standard? Four clinical studies on humans, assessing the diagnostic accuracy of portable instrumental approaches (i.e. Bitestrip, electromyography (EMG)-telemetry recordings and Bruxoff) with respect to PSG, were included in the review. Methodological shortcomings were identified by QUADAS-2 quality assessment. Findings showed contrasting results and supported only in part the validity of the described diagnostic devices with respect to PSG. The positive predictive value (PPV) of the Bitestrip device was 59-100%, with a sensitivity of 71-84·2%, whilst EMG-telemetry recordings had an unacceptable rate of false-positive findings (76·9%), counterbalanced by an almost perfect sensitivity (98·8%). The Bruxoff device had the highest accuracy values, showing an excellent agreement with PSG for both manual (area under ROC = 0·98) and automatic scoring (0·96) options as well as for the simultaneous recording of events with respect to PSG (0·89-0·91). It can be concluded that the available information on the validity of portable instrumental diagnostic approaches with respect to PSG recordings is still scarce and not solid enough to support any non-PSG technique's employ as a stand-alone diagnostic method in the research setting, with the possible exception of the Bruxoff device that needs to be further confirmed with future investigations.

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The case report of a patient is presented who had been suffering from a plasmacytoma of the spine several years back, and who had developed a new plasmacytoma of the mandible, 3 years subsequent to the insertion of a dental implant. This second solitary lesion occurred 15 years after the first one, and without signs of conversion to multiple myeloma. Research in animal models has shown multinucleated giant cells, belonging to the monocyte-macrophage lineage, persisting between the titanium surface and the lymphohemopoietic compartment, at least 1.5 years after implant insertion. Factors that increase the proliferative activity of precursor B cells, for example a protracted macrophage activation, are likely to increase the risk of B cell oncogenesis. A possible role of the titanium surface in an increase of precursor B cell proliferative activity, thus facilitating a new localization, was evaluated.