Why does composite shrink

J Dent Res 87 , — Jansen, J. Macromolecules 36 , — Dickens, S. Photopolymerization kinetics of methacrylate dental resins. Smith, D. Direct filling resins: dimensional changes resulting from polymerization shrinkage and water sorption. J Am Dent Assoc 46 , — Lai, J. Measuring polymerization shrinkage of photo-activated restorative materials by a water-filled dilatometer.

Dent Mater 9 , — Cook, W. A simple method for the measurement of polymerization shrinkage in dental composites. Dent Mater 15 , — Puckett, A. Method to measure the polymerization shrinkage of light-cured composites. J Prosthet Dent 68 , 56—58 Naoum, S. Polymerization profile analysis of resin composite dental restorative materials in real time. J Dent 40 , 64—70 Sharp, L.

Volumetric shrinkage of composites using video-imaging. Journal of Dentistry 31 Sun, J. X-ray microcomputed tomography for measuring polymerization shrinkage of polymeric dental composites. Dent Mater 24 , — Lee, I.

A new method to measure the polymerization shrinkage kinetics of light cured composites. J Oral Rehabil 32 , — Lee, H. Physical properties of four thermosetting dental restorative resins.

J Dent Res 48 , — Sakaguchi, R. Strain gauge method for measuring polymerization contraction of composite restoratives. J Dent 19 , — Fano, V. Polymerization shrinkage of microfilled composites determined by laser beam scanning. Biomaterials 18 , — Simon, Y. Video-controlled characterization of polymerization shrinkage in light-cured dental composites. Polymer Testing 27 , — Stavridakis, M. Linear displacement and force induced by polymerization shrinkage of resin-based restorative materials.

Am J Dent 16 , — PubMed Google Scholar. Berghmans, F. Dental composite resins: measuring the polymerization shrinkage using optical fiber Bragg grating sensors. Anttila, E. Evaluation of polymerization shrinkage and hydroscopic expansion of fiber-reinforced biocomposites using optical fiber Bragg grating sensors.

Soares, C. Polymerization shrinkage stress of composite resins and resin cements - What do we need to know? Brazilian Oral Research 31 , 49—63 Kamalak, H. Evaluation of polymerization shrinkage of dental composites by microcomputed tomography. Biomedical Research 29 , — CAS Google Scholar. El-Korashy, D. Post-gel shrinkage strain and degree of conversion of preheated resin composite cured using different regimens. Oper Dent 35 , — Analysis of strain gage method for measurement of post-gel shrinkage in resin composites.

Dent Mater 13 , — Cehreli, M. Comparison of post-gel shrinkage strains in light-polymerized composite resins. J Prosthet Dent 88 , — Tezvergil, A. The effect of fiber orientation on the polymerization shrinkage strain of fiber-reinforced composites. Milczewski, M. Determination of setting expansion of dental materials using fibre optical sensing. Measurement Science and Technology 17 , — Shouha, P. The effect of fiber aspect ratio and volume loading on the flexural properties of flowable dental composite.

Dent Mater 30 , — Rao, Y. In-fibre Bragg grating sensors. Measurement Science and Technology 8 , — Determination of double bond conversion in dental resins by near infrared spectroscopy.

Dent Mater 17 , 71—79 Caldas, D. Influence of curing tip distance on resin composite Knoop hardness number, using three different light curing units. Oper Dent 28 , — Price, R. Composite resin restorations on posterior teeth. Adhesion: The Silent Revolution in Dentistry. Chicago: Quintessence; Effect of various incremental techniques on the marginal adaptation of class II composite resin restorations.

A visible light activated resin cured through tooth structure. Gen Dent. Liebenberg WH. Successive cusp build-up: an improved placement technique for posterior direct resin restorations. Improved proximal margin adaptation of Class II composite resin restorations by use of light-reflecting wedges. Quintessence Int. Losche GM. Marginal adaptation of Class II composite resin fillings: guided polymerization vs reduced light intensity. J Adhes Dent. Bichacho N. The centripetal build-up for composite resin posterior restorations.

Pract Periodontics Aesthet Dent. Belvedere PC. Contemporary posterior direct composites using state-of-the-art techniques. Dent Clin North Am. Microleakage of Class I composite resin restorations cured with three methods [abstract]. Microleakage of Class I composite resin restorations cured with four methods [abstract]. Bisphenol-A content of resin monomers and related degradation products.

Clin Oral Investig. Effect of insertion technique on microleakage in mesio-occlusodistal composite resin restorations. Effect of placement techniques on microleakage of a dentin-bonded composite resin.

Coli P, Brannstrom M. The marginal adaptation of four different bonding agents in Class II composite resin restorations applied in bulk or in two increments. Does an incremental filling technique reduce polymerization shrinkage stresses? Curing light intensity and marginal leakage of resin composite restorations.

Microleakage of Class V restorations with different visible-light curing methods. Walker R, Burgess JO.

Microleakage of Class V restorations with different curing methods. Kanca J 3rd, Suh BI. Pulse activation: reducing resin-based composite contraction stresses at the enamel cavosurface margins.

Am J Dent. Clinical evaluation of composite restorations polymerized by two different methods. Two year results [abstract]. Germain HA Jr. One-year clinical performance of a self-etching adhesive in class V resin composites cured by two methods. Relaxation of polymerization contraction shear stress by hygroscopic expansion. John O. Navigation Home Publications Publications. Don't miss a digital issue! Inside Dentistry September Volume 3, Issue 8.

Just like a wool sweater shrinking in a hot dryer, composites will shrink during polymerization. This is the process whereby simple molecules called monomers combine to form larger, more complex molecules, or polymers. Depending on the monomers combined, the resulting product can have any number of unique physical properties, including strength or elasticity. However, polymerization can also have some unavoidable adverse outcomes.

For restorative composites, when the resin converts from a semi-liquid or paste to a solid, its density changes along with its overall volume — literally decreasing in size. Conventional materials shrink by about 1. What would happen if you decided to keep wearing it? Beyond being uncomfortable and tight, the tiny sweater would take up less space physically — leaving gaps at your wrists, waist and in your closet.

On its own, the shrunken sweater or polymerized composite is smaller and takes up less space — but on your body and in a cavity, it can cause a lot of discomfort.

Shrinkage stress is the pressure put on the adhesive and surrounding tooth structure during the polymerization process. The stress developed in a restoration can be relieved quickly by the flow of material still in the pre-gel phase. Residual stresses arise after gelation. Both auto- as well as photo-curing composites were analyzed. In photo-curing composites, the gel-point varies throughout the material with the intensity of the light.