Clinical studies

In vitro evaluation of three curettes with edge retention technology after extended use.

Sisera, M; Hofer, D J; Sener, B; Attin, T; Schmidlin, P R (2009). Schweizer Monatsschrift für Zahnmedizin SMfZ, 119(12):1200-1208.


Summary This study assessed the edge cutting efficiency of three new curettes with different edge retention echnologies after simulated wear in vitro. Three test curettes (two with a titanium nitride coating and one without coating, but made of a cryogenically treated stainless steel alloy) were used to root plane prepared bovine dentin specimens. Nine curettes of each type were used to instrument one dentin sample each. Dentin removal was determined after the first ten strokes and again cumulatively for the strokes 500–510 and 1,000–1,010 by means of atomic absorption spectrophotometry (AAS). The effects of chemical and thermal stress were analysed after repeated disinfection and sterilization of the instruments then followed by a final 10-stroke sequence of dentin removal to determine cutting efficacy. A standard, untreated stainless steel curette was used as a control. Test and control instruments showed no statistical evidence of diminished dentin removal over 1010 strokes. Dentin surface roughness also displayed insignificant differences for all instruments. However, sterilization negatively affected the test and control instruments to an equal degree. Sterilization procedures appear to be an important factor in the dulling of curettes, which affected dentin removal efficacy but not surface roughness.



FDI World Dental Federation - clinical criteria for the evaluation of direct and indirect restorations. Update and clinical examples.

Reinhard Hickel, Arnd Peschke, Martin Tyas, Ivar Mjör, Stephen Bayne, Mathilde Peters, Karl-Anton Hiller, Ross Randall, Guido Vanherle, Siegward D. Heintze.


In 2007, new clinical criteria were approved by the FDI World Dental Federation and simultaneously published in three dental journals. The criteria were categorized into three groups: esthetic parameters (four criteria), functional parameters (six criteria), and biological parameters (six criteria). Each criterion can be expressed with five scores, three for acceptable and two for non-acceptable (one for reparable and one for replacement). The criteria have been used in several clinical studies since 2007, and the resulting experience in their application has led to a requirement to modify some of the criteria and scores. The two major alterations involve staining and approximal contacts. As staining of the margins and the surface have different causes, both phenomena do not appear simultaneously. Thus, staining has been differentiated into marginal staining and surface staining. The approximal contact now appears under the name "approximal anatomic form" as the approximal contour is a specific, often non-esthetic issue that cannot be integrated into the criterion "esthetic anatomical form". In 2008, a web-based training and calibration tool called e-calib ( was made available. Clinical investigators and other research workers can train and calibrate themselves interactively by assessing clinical cases of posterior restorations, which are presented as high quality pictures. Currently, about 300 clinical cases are included in the database which is regularly updated. Training for 8 of the 16 clinical criteria is available in the program: "Surface luster"; "Staining (surface, margins)"; "Color match and translucency"; "Esthetic anatomical form"; "Fracture of material and retention"; "Marginal adaptation"; "Recurrence of caries, erosion, abfraction"; and "Tooth integrity (enamel cracks, tooth fractures)". Typical clinical cases are presented for each of these eight criteria and their corresponding five scores..