The effect of specimen temperature on the polymerization of a resin-composite

Price, Richard; Whalen, J. Marc; Price, Thomas B.; Felix, Christopher M; Fahey, John

doi:10.1016/j.dental.2011.06.004

Cited by 60 publications

(41 citation statements)

References 25 publications

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“…The greater size of the sample specimens and the room-temperature storage conditions might explain the slower increase in setting in the previous report. Curing temperature (room temperature vs oral environment) significantly affects the rate and extent of polymerization (20,21), as well as the strain values (21). One study (10) reported a setting time for RSSE of 45 min at 37ºC, which agrees with data from the manufacturer.…”

Section: Discussionsupporting

confidence: 76%

Degree of conversion of a self-adhesive endodontic sealer when used as bulk material

Pérez-González

Bolaños-Carmona

Pérez-Gómez

et al. 2016

Journal of Oral Science

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This study tested the null hypothesis that the opacity of RealSeal SE (RSSE) sealer makes light-curing inefficient, while the degree of conversion (DC) is similar regardless of curing method. Fourteen uniradicular teeth were sectioned at 15 mm from the apex. Root canals were instrumented using the Reciproc file system, bulk-filled with RSSE, and divided randomly into two groups (dual-cure or self-cure). DC was determined by micro-Raman spectroscopy at 24 h, 48 h, and 1 week after filling, at 6, 9, and 12 mm from the coronal end. Contrast ratio (Yb/ Yw) was used to determine the opacity of the material. Descriptive statistics and nonparametric tests were used, and significance was defined as a P value of less than 0.05. Opacity was almost total by the first section, at 6 mm. In dual-cure mode, DC values at 24 h were lower in the apical section (63.8%) than in the more coronal sections and were lower than in selfcured specimens (87.4%). Light-curing of the coronal end did not improve DC. These differences remained at 48 h and 1 week. Only a small (2%) but significant increase in DC was observed in evaluations at 24 h and 1 week. (J Oral Sci 58, 333-338, 2016)

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Section: Discussionsupporting

confidence: 76%

Degree of conversion of a self-adhesive endodontic sealer when used as bulk material

Pérez-González

Bolaños-Carmona

Pérez-Gómez

et al. 2016

Journal of Oral Science

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“…Moreover, the temperature during polymerization can significantly affect polymerization efficiency, and a rise from room temperature (22˚C) to mouth temperature (35˚C) has been shown to result in increased DC due to improved monomer mobility [54]. Taking these parameters that influence the final DC, in the present study, all measurements were conducted after 24-h-darkstorage at 37°C.…”

Section: Discussionmentioning

confidence: 99%

“…The lower hardness values might be due to the fact that, in order to avoid any heat production, the composite specimens were not ground or polished prior to hardness testing, so that measurements were performed on the specimens' resin-rich outer layer [54]. Furthermore, a relatively low indenter load of 10 g was used in this study, which has been shown to result in lower KHN-values compared to those recorded after higher indenter load application [60].…”

Section: Discussionmentioning

confidence: 99%

Influence of irradiation time on subsurface degree of conversion and microhardness of high-viscosity bulk-fill resin composites

et al. 2014

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OBJECTIVES To evaluate the influence of irradiation time on degree of conversion (DC) and microhardness of high-viscosity bulk-fill resin composites in depths up to 6 mm. MATERIALS AND METHODS Four bulk-fill materials (Tetric EvoCeram Bulk Fill-TECBF; x-tra fil-XF; QuixFil-QF; SonicFill-SF) and one conventional nano-hybrid resin composite (Tetric EvoCeram-TEC) were irradiated for 10, 20, or 30 s at 1,170 mW/cm(2). DC and Knoop microhardness (KHN) were recorded after 24-h dark storage at five depths: 0.1, 2, 4, 5, and 6 mm. Data were statistically analyzed using ANOVA and Bonferroni's post-hoc test ( = 0.05). RESULTS With increasing bulk thickness, DC and KHN significantly decreased for TEC. TECBF and SF showed a significant decrease in DC and KHN at 4-mm depth after 10-s irradiation, but no decrease in DC after 30-s irradiation (p > 0.05). XF and QF demonstrated no significant DC decrease at depths up to 6 mm after irradiation of at least 20 s. At 4-mm depth, all materials tested achieved at least 80 % of their maximum DC value, irrespective of irradiation time. However, at the same depth (4 mm), only XF and QF irradiated for 30 s achieved at least 80 % of their maximum KHN value. CONCLUSIONS Regarding DC, the tested bulk-fill resin composites can be safely used up to at least 4-mm incremental thickness. However, with respect to hardness, only XF and QF achieved acceptable results at 4-mm depth with 30 s of irradiation. CLINICAL RELEVANCE Minimum irradiation times stated by the manufacturers cannot be recommended for placement of highviscosity bulk-fill materials in 4-mm increments. Conclusions: Regarding DC, the tested bulk-fill resin composites can be safely used up to at least 4-mm incremental thickness. However, with respect to hardness, only XF and QF achieved acceptable results at 4-mm depth with 30 s of irradiation.Clinical relevance: Minimum irradiation times stated by the manufacturers cannot be recommended for placement of high-viscosity bulk-fill materials in 4-mm increments.

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“…In addition, microhardness, as an indirect measure of the degree of conversion [28,29], was assessed at both the top and bottom surface of the composite specimens in order to allow an estimation of the extent of resin polymerization. …”

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confidence: 99%