Statement Of Problem: Cavity preparations have routinely been associated with decreased fracture strength of restored teeth.
Purpose: The purpose of this study was to evaluate the influence of endodontic treatment and thermal cycling on the fracture resistance of teeth restored with ceramic or composite resin inlay restorations.
Material And Methods: One hundred sound, maxillary premolars were selected. Twenty intact teeth served as a control group. Eighty teeth were prepared with MOD cavity preparations; half of them were also endodontically treated. Inlay restorations were prepared with composite resin (Filtek Z250) or feldspathic ceramic (Vitadur Alpha). Half of the specimens for each group were submitted to thermal cycling (500 cycles, between 5 and 55 degrees C, dwell time of 30 seconds). The specimens were subjected to compressive axial loading using a steel ball. Data were analyzed using 3-way ANOVA and post hoc Tukey's test (alpha=.05).
Results: Except for those teeth restored with ceramic without endodontic treatment and thermal cycling, no other group achieved fracture strength similar to sound teeth. Ceramic and composite resin restorations provided similar resistance to fracture. There was a significant interaction between endodontic therapy and thermal cycling (P<.001). In the nonthermal cycled groups, endodontically treated teeth showed significantly lower fracture resistance (P<.001). All experimental groups had similar fracture strength when submitted to thermal cycling.
Conclusions: Both restorative techniques provided similar fracture resistance. Endodontic treatment decreased the fracture resistance of nonthermal cycled specimens, while thermal cycling decreased the fracture resistance of nonendodontically treated specimens.
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http://dx.doi.org/10.1016/S0022-3913(07)60054-7 | DOI Listing |
J Therm Biol
January 2025
School of Exercise and Health, Shanghai University of Sport, Shanghai, 200438, China. Electronic address:
This study investigated the single and combined effects of environmental heat stress and physical exercise on executive function (EF) performance, prefrontal cortex oxygenation, thermoregulatory responses and subjective perceptions. Sixteen subjects participated in four experimental sessions: two under moderate environmental conditions (23 °C), with and without physical exercise (R23, E23), and two under hot environmental conditions (35 °C), with and without physical exercise (R35, E35). In each session, participants completed EF tasks before and after 1 h of passive rest or 45 min of moderate-intensity cycling followed by 15 min of rest.
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State Key Laboratory of Materials-Oriented Chemical Engineering and School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
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View Article and Find Full Text PDFJ Chem Phys
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School of Chemistry, University of Lincoln, Brayford Pool, LN6 7TS Lincoln, United Kingdom.
We analyzed the thermal, structural, and dynamic properties of maghemite using classical molecular dynamics, focusing on bulk and nanoparticle systems. We explored their behavior when heated to high temperatures (above the melting point) and during cooling, as well as under thermal cycles ending at intermediate temperatures. Our findings show that in the bulk system, both the tetrahedral and octahedral iron sub-lattices undergo a phase transition prior to melting.
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View Article and Find Full Text PDFThe increasing demand for sustainable food packaging has driven the development of films based on biopolymers. However, enhancing their functional properties remains a challenge. In the current study, potato starch-pectin (PSP) composite films were fabricated and enriched with juniper berry essential oil (JBEO) to improve their physicochemical properties.
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