J Biomed Mater Res B Appl Biomater
November 2012
The study objective was to correlate wear between an in vitro method for simulating wear and in vivo wear of a posterior dental composite. Ten subjects (12 restorations) were selected from a five-year clinical study (University of North Carolina, School of Dentistry) that assessed wear of SureFil composite (Caulk, Dentsply). Subject casts were digitized and changes in volume and mean depth with time were calculated from the 3D digital models for contact and contact-free wear.
View Article and Find Full Text PDFBackground: Acid regurgitation resulting from gastroesophageal reflux disease (GERD) causes dissolution of tooth structure. The authors conducted a longitudinal clinical study to measure tooth surface loss associated with GERD.
Methods: The authors made replicas of dental impressions obtained from 12 participants with GERD and six control participants at baseline and six months.
Objectives: To use profilometry to assess the margin surface profile of all-ceramic crowns (ACC's) at try-in and 1-week after cementation with dual-cured resin (DC, RelyX ARC, 3M ESPE, St. Paul, MN, USA), self-adhesive dual-cured resin (SADC, RelyX Unicem, 3M ESPE), light-cured resin (LC, RelyX Veneer, 3M ESPE) or chemically cured resin-modified glass ionomer (RMGI, RelyX Luting Plus, 3M ESPE) luting cement.
Methods: Forty, sound, extracted, human, premolar teeth underwent a standardised preparation for ACC's.
Objective: To quantify luting cement at the crown-tooth interface of esthetic crowns fabricated using four different techniques and two methods of excess cement removal.
Material And Methods: Four methods of crown fabrication were used: the feldspathic porcelain and platinum foil technique, the feldspathic porcelain and refractory die technique, the resin composite crown and CAD/CAM technique, and the feldspathic porcelain crown and CAD/CAM technique. Half of the cemented crowns were allocated to Group A: removal of excess cement by flicking-off with a plastic instrument 3 min after initial polymerization, or Group B: removal of excess cement using a wiping action with cotton pellets.
Teeth with white spot lesions (WSL) might be more prone to enamel loss during bracket debonding. This in vitro study compared enamel loss from teeth with (n = 14) and without (n = 14) WSL after polishing with low-speed finishing burs or disks (Sof-Lex, 3M ESPE, St Paul, Minn). Debonded surfaces were analyzed with a contact stylus profilometer, and digitized data were compared with baseline readings by using AnSur NT software (Regents, University of Minnesota, Minneapolis, Minn).
View Article and Find Full Text PDFObjective: Experimental measurements on various restoration configurations have shown that restored teeth deform under the influence of polymerization shrinkage, but actual residual stresses could not be determined. The purpose of this study was to calculate and validate shrinkage stresses associated with the reported tooth deformations.
Methods: Three different restoration configurations were applied in a finite element model of a molar.
Objective: Residual stresses from polymerization shrinkage in composite restorations deform a tooth. This may cause debonding, enamel crack propagation, and post-operative sensitivity. Deformation due to shrinkage has been measured previously at a few discrete points.
View Article and Find Full Text PDFStatement Of Problem: Many different rotary instruments are available for shaping composite restorations. Whether use of these instruments causes undesirable iatrogenic abrasion of either the tooth surface or the composite restorative material is unknown. Assuming that damage occurs, which technique is least damaging is unknown.
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