The Dependence of Shrinkage Stress Reduction on Porosity Concentration in Thin Resin Layers

Introduction Dimensional stability of polymer-based dental materials is compromised by polymerization reaction of the monomer. The conversion into a polymer is accompanied by a closer packing of molecules, which leads to volume reduction called curing contraction or polymerization shrinkage. Curing contraction may break the adhesion between the adhesive system and hard tooth tissues forming micrographs which may result in marginal deterioration, recurrent caries and pulp injury. Polymerization shrinkage of resin-based restorative dental materials Polymerization of the organic phase (monomer molecules) of resin-based dental materials causes shrinkage. The space occupied by filler particles is not associated with polymerization shrinkage. However, high filler loading within certain limits, can contribute to a lesser curing contraction. Polymerization shrinkage stress and stress reduction possibilities Polymerization shrinkage stress of polymer-based dental resins can be controlled in various ways. The adhesive bond in tooth-restoration interface guides the contraction forces to cavity walls. If leakage occurs, complications like secondary caries and pulpal irritation may jeopardize the longevity of a restoration. Stress relieve can be obtained by modifications of the monomer and photoinitiator, or by specially designed tooth preparation and application of bases and liners of low modulus of elasticity. The polymerization contraction can be compensated by water absorption due to oral cavity surrounding. The newest approach to stress relief is based on modulation of polymerization initiation. Conclusion This work deals with polymerization contraction and how to achieve leak-proof restoration. Restorative techniques that may reduce the negative effect of polymerization shrinkage stress need further research in order to confirm up-to-date findings.

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Formation of Diagonal Gaps as Stress-Relieving Sites: Rethinking the Concept of Increment Splitting in Direct Occlusal Composite Restorations

Journal of Dentistry and Oral Epidemiology ◽

10.54289/jdoe2100101-1 ◽

2021 ◽

Vol 1 (1) ◽

pp. 1-7

Author(s):

Khamis A Hassan

Keyword(s):

Stress Reduction ◽

Three Dimensional ◽

Current Paper ◽

Shrinkage Stress ◽

Polymerization Shrinkage ◽

Composite Restorations ◽

Stress Relieving ◽

Light Curing ◽

As Stress ◽

Vertical Gap

The split-increment horizontal placement technique is currently used, along with other restorative techniques, in moderate-to-large occlusal cavities for reducing the shrinkage stress generated during light polymerization. Such stress, if released uncontrolled, may cause damage within the composite, tooth or at the adhesive interface. The term “diagonal cut” was used in our original paper published in 2005 to refer to the action of dividing each composite increment into segments prior to light polymerization and was presented in two-dimensional illustration. Besides, we made no mention in the original paper of the term “diagonal gap” as an outcome of such diagonal cutting. We currently recognize the importance of introducing the “diagonal gap” term and the need for shedding some light on its role to help provide a more comprehensive view of the split-increment technique. The purpose of the current paper is to rethink our increment splitting concept used in direct occlusal composite restorations by introducing the term “diagonal gap” as a stress-relieving vertical site and demonstrating it in a three-dimensional illustration for providing a more comprehensive understanding of the split-increment technique. Conclusion: In the current paper, the term “diagonal gap” is introduced to refer to the vertical gap created by diagonal cutting of the horizontal composite increment, before light curing. This gap enables the segmented composite increment to undergo unrestrained shrinkage, where each segment being free from adhesion at the gap site can deform independently from the other segments. The relief of the polymerization shrinkage stress generated during light curing prevents formation of cracks in enamel and/or composite, and debonding of adhesive interfaces. Keywords: deformation; diagonal gap; incremental; occlusal; polymerization shrinkage; posterior composite; segment; split-increment; stress reduction; stress-relieving site

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Photopolymerization shrinkage-stress reduction in polymer-based dental restoratives by surface modification of fillers

Dental Materials ◽

10.1016/j.dental.2021.01.013 ◽

2021 ◽

Vol 37 (4) ◽

pp. 578-587

Author(s):

Parag K. Shah ◽

Jeffrey W. Stansbury

Keyword(s):

Surface Modification ◽

Stress Reduction ◽

Shrinkage Stress ◽

Dental Restoratives

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A comprehensive stress-reduction program for dental students

Journal of Dental Education ◽

10.1002/j.0022-0337.1984.48.4.tb01776.x ◽

1984 ◽

Vol 48 (4) ◽

pp. 203-207 ◽

Cited By ~ 4

Author(s):

RM Schwartz ◽

CR Eigenbrode ◽

O Cantor

Keyword(s):

Stress Reduction ◽

Dental Students ◽

Reduction Program

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Achtsamkeitsbasierte kognitive Therapie

Zeitschrift für Klinische Psychologie und Psychotherapie ◽

10.1026/1616-3443/a000280 ◽

2014 ◽

Vol 43 (4) ◽

pp. 233-240 ◽

Cited By ~ 1

Author(s):

Thomas Heidenreich ◽

Christoph Grober ◽

Johannes Michalak

Keyword(s):

Cognitive Therapy ◽

Stress Reduction ◽

Kognitive Therapie ◽

Mindfulness Based Stress Reduction ◽

Praktische Umsetzung

Unter den im Zentrum dieses Sonderhefts stehenden Neuentwicklungen nehmen achtsamkeitsbasierte Verfahren eine bedeutsame Rolle ein: Während die „Achtsamkeitsbasierte Stressreduktion” (mindfulness-based stress reduction, MBSR) bereits in der zweiten Hälfte der 1970er Jahre entwickelt wurde ( Kabat-Zinn, 1990 ), erlangte insbesondere die von Segal, Williams und Teasdale (2002) speziell für die Rückfallprävention bei rezidivierender depressiver Störung entwickelte „Achtsamkeitsbasierte Kognitive Therapie” (mindfulness-based cognitive therapy, MBCT) eine zunehmende Bedeutung im Bereich kognitiv-behavioraler Ansätze. Der vorliegende Beitrag geht zunächst auf den historischen und theoretischen Hintergrund der Achtsamkeitsbasierten Kognitiven Therapie ein. Im Anschluss daran wird die praktische Umsetzung des Gruppenkonzepts vorgestellt und der Stand der Forschung anhand aktueller Metaanalysen referiert. Der Beitrag schließt mit einer kritischen Diskussion einer allzu verkürzten Anwendung von Achtsamkeit in der klinischen Praxis.

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