A new method to measure the polymerization shrinkage kinetics of composites using a particle tracking method with computer vision.
OBJECTIVE
The aim of this study was to develop a new method to measure the polymerization shrinkage of light cured composites and to evaluate the overall utility and significance of the technique.


METHODS
An optical instrument to measure the linear polymerization shrinkage of composites without directly contacting the specimen was developed using a particle tracking method with computer vision. The measurement system consisted of a CCD color video camera, a lens, an image storage device, and image processing and analysis software. The shrinkage kinetics of a commercial silorane-based composite (P90) and two conventional methacrylate-based composites (Z250 and a flowable Z350) were investigated and compared with the data measured using the "bonded disc method".


RESULTS
The linear shrinkage of the composites was 0.33-1.41%. The shrinkage value was lowest for the silorane-based (P90) composite and highest for the flowable Z350 composite. The estimated volume shrinkages of the materials were comparable to the axial shrinkages measured with the bonded disc method.


CONCLUSIONS
The new instrument was able to measure the true linear shrinkage of composites without sensitivity to the specimen geometry and the viscosity of the material. Therefore, this instrument can be used to characterize the shrinkage kinetics for a wide range of commercial and experimental visible-light-cure materials in relation to the composition and chemistry.
Department of Conservative Dentistry and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, South Korea. inboglee@snu.ac.kr
In-Bog
IB
Lee
Sun-Hong
SH
Min
Deog-Gyu
DG
Seo
D000465:Algorithms; D003116:Color; D003188:Composite Resins / Q000737:chemistry*; D003199:Computer Systems; D003764:Dental Materials / Q000737:chemistry*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016247:Information Storage and Retrieval; D007700:Kinetics; D008422:Materials Testing; D058105:Polymerization; D062047:Silorane Resins; D012833:Siloxanes / Q000737:chemistry; D012984:Software; D013314:Stress, Mechanical; D013499:Surface Properties; D014741:Video Recording / Q000295:instrumentation
D003188:Composite Resins; D003764:Dental Materials; C444701:Filtek Z250; D062047:Silorane Resins; D012833:Siloxanes; C544925:filtek P90; C533204:filtek Z350; C555513:silorane composite resin