No abstract

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)