Time-dependent degree of conversion, Martens parameters, and flexural strength of different dual-polymerizing resin composite luting materials

Kelch, Matthias; Stawarczyk, Bogna; Mayinger, Felicitas

doi:10.1007/s00784-021-04091-4

Cited by 17 publications

(22 citation statements)

References 32 publications

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“…In line with the present findings, the sole use of self-polymerization has been observed to lead to a reduced DC and lower mechanical properties [10,17,18,29]. However, with post-polymerization continuing over a period of up to 24 h after the start of the reaction, the DC and the interrelated mechanical properties of self-polymerized specimens may increase over time and align with those reported for their light-polymerized counterparts [30,31]. A previous investigation on the polymerization kinetics of bulk-fill resin composites reported self-and light-polymerization to only compete in the initial stage of polymerization.…”

Section: Discussionsupporting

confidence: 89%

Chemical and mechanical properties of dual-polymerizing core build-up materials

2022

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Objectives To investigate the chemical (degree of conversion (DC)) and mechanical properties (Martens hardness (HM), elastic indentation modulus (EIT), and biaxial flexural strength (BFS)) of four dual-polymerizing resin composite core build-up materials after light- and self-polymerization. Materials and methods Round specimens with a diameter of 12 mm and a thickness of 1.5 mm were manufactured from CLEARFIL DC CORE PLUS (CLE; Kuraray), core·X flow (COR; Dentsply Sirona), MultiCore Flow (MUL; Ivoclar Vivadent), and Rebilda DC (REB; VOCO) (N = 96, n = 24/material). Half of the specimens were light-polymerized (Elipar DeepCure-S, 3 M), while the other half cured by self-polymerization (n = 12/group). Immediately after fabrication, the DC, HM, EIT, and BFS were determined. Data was analyzed using Kolmogorov–Smirnov, Mann–Whitney U, and Kruskal–Wallis tests, Spearman’s correlation, and Weibull statistics (p < 0.05). Results Light-polymerization either led to similar EIT (MUL; p = 0.119) and BFS (MUL and REB; p = 0.094–0.326) values or higher DC, HM, EIT, and BFS results (all other groups; p < 0.001–0.009). When compared with the other materials, COR showed a high DC (p < 0.001) and HM (p < 0.001) after self-polymerization and the highest BFS (p = 0.020) and Weibull modulus after light-polymerization. Positive correlations between all four tested parameters (R = 0.527–0.963, p < 0.001) were found. Conclusions For the tested resin composite core build-up materials, light-polymerization led to similar or superior values for the degree of conversion, Martens hardness, elastic indentation modulus, and biaxial flexural strength than observed after self-polymerization. Among the tested materials, COR should represent the resin composite core build-up material of choice due to its high chemical (degree of conversion) and mechanical (Martens hardness, elastic indentation modulus, and biaxial flexural strength) properties and its high reliability after light-polymerization. The examined chemical and mechanical properties showed a positive correlation. Clinical relevance The chemical and mechanical performance of dual-polymerizing resin composite core build-up materials is significantly affected by the chosen polymerization mode.

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Section: Discussionsupporting

confidence: 89%

Chemical and mechanical properties of dual-polymerizing core build-up materials

2022

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“…The DC percentage of a resin-matrix cement through an indirect restoration is typically measured to be between 55 and 75%, as seen in Table 1 [ 2 , 65 ]. An insufficient DC percentage of monomers can increase the solubility, causing microleakage at margin restorations [ 89 ]. Thus, a high DC and an efficient polymerization depend on several factors such as (i) light irradiance, (ii) exposure time [ 90 ], (iii) visible light wavelength, (iv) organic matrix type, size, and content of inorganic fillers, (v) distance between the LCU and resin-matrix cement [ 91 ], and (vi) the refraction index of the organic and inorganic components [ 40 , 92 ].…”

Section: Resultsmentioning

confidence: 99%

A Scoping Review on the Polymerization of Resin-Matrix Cements Used in Restorative Dentistry

et al. 2023

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In dentistry, clinicians mainly use dual-cured or light-cured resin-matrix cements to achieve a proper polymerization of the organic matrix leading to enhanced physical properties of the cement. However, several parameters can affect the polymerization of resin-matrix cements. The main aim of the present study was to perform a scoping review on the degree of conversion (DC) of the organic matrix, the polymerization, and the light transmittance of different resin-matrix cements used in dentistry. A search was performed on PubMed using a combination of the following key terms: degree of conversion, resin cements, light transmittance, polymerization, light curing, and thickness. Articles in the English language published up to November 2022 were selected. The selected studies’ results demonstrated that restorative structures with a thickness higher than 1.5 mm decrease the light irradiance towards the resin-matrix cement. A decrease in light transmission provides a low energy absorption through the resin cement leading to a low DC percentage. On the other hand, the highest DC percentages, ranging between 55 and 75%, have been reported for dual-cured resin-matrix cements, although the polymerization mode and exposure time also influence the DC of monomers. Thus, the polymerization of resin-matrix cements can be optimized taking into account different parameters of light-curing, such as adequate light distance, irradiance, exposure time, equipment, and wavelength. Then, optimum physical properties are achieved that provide a long-term clinical performance of the cemented restorative materials.

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“…Polymerisation of resin cements typically progresses over 24-48 h before complete maturation [15,25,53]. Unfortunately, poor marginal adaptation of the restoration exposing the luting cement to the oral environment could compromise its integrity over time [25].…”

Section: Polymerisation Of the Luting Cements (1 H Postcuring)mentioning

confidence: 99%

“…Several internal and external factors influence the polymerisation of these adhesive resin cements. External variables such as the light curing unit (LCU) [12,22], the restorative substrate [23,24], the ageing time and condition after curing were investigated [25]. As regards the LCU, polymerisation of resin cements could be affected by its wavelength distribution [26], the radiant exposure received [27], the duration of exposure [24], and the tip diameter and its distance from the restoration [26,28].…”

Section: Introductionmentioning

confidence: 99%

“…Changes in refractive index or microhardness (Vickers and Knoop) have been used to indicate the progress of polymerisation [32,33,41]. Recently, Martens hardness (H M ) has been measured via a series of force-controlled indentations to analyse the ageing behaviour of six dual-cured luting cements after photoactivation through a 1-mm thick zirconia substrate over 7 d [25]. Results indicated that complete polymerisation was achieved after 2 d post curing.…”

Section: Introductionmentioning

confidence: 99%

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