NIOM’s Senior Scientist John Tibballs participated in ISO workshop -

Senior Scientist John Tibballs participated in ISO Workshop for Chairs and Convenors “Effective ISO Meetings”. Tibballs is convenor of the working group WG 3 “Digitizing devices” of subcommittee SC 9 “CAD/CAM systems” under Technical Committee ISO TC 106 “Dentistry”.

Improved composite repair -

Repairing and extending composite restorations are common and well-accepted procedures for the dental practitioner. Evaluation of the repair strength has great research focus by using tensile and shear bond strength measurements. The present collaborative study from NIOM has assessed the effect of surface treatments and bonding systems on the repair bond strength between composite materials after 1 and 12 months of storage, using a tensile test method.

Thermocycling -

The delightful combination of a coffee and an ice cream sets the parameters for one of the most used test protocols for dental materials. The international standard for testing dental adhesives stipulates an ageing procedure in which test specimens are held repeatedly first in 5 °C cold water and then in 55 °C hot water for a large number of cycles. The result of subsequent testing invariably shows degradation in adhesive strength. It is important that this loss of bonding is limited.

Fractures in dental ceramics: research and clinical experience -

The main problem with ceramics as biomaterials is that they are brittle. One focus of research and development has been on improving the materials’ fracture strength and thereby increasing the clinical success rates for dental, all-ceramic restorations. The most advanced dental ceramics should, according to in vitro testing, be able to withstand human mastication forces.

Clinically relevant fracture testing of all-ceramic crowns -

Fracture strength measured in vitro indicates that most all-ceramic crowns should be able to withstand mastication forces. Nevertheless, fractures are one of the major clinical problems with all-ceramic restorations. Furthermore, the fracture mode of all-ceramic crowns observed in clinical use differs from that found in conventional fracture strength tests. The aim of the present study was to develop and investigate a method that simulates clinical fracture behavior in vitro