UNIVERSIDADE ESTADUAL PAULISTA

“JÚLIO DE MESQUITA FILHO”

Instituto de Ciência e Tecnologia

Campus de São José dos Campos

ORIGINAL ARTICLE DOI: https://doi.org/10.4322/bds.2025.e4750

Braz Dent Sci 2025 Apr/Jun;28 (2): e4750

This is an Open Access article distributed under the terms of the Creative Commons Attribution license (https://creativecommons.org/licenses/by/4.0/), which permits

unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Multi-peak light sources can improve the physical and mechanical

properties of a zirconia- and diatomite-based dental resin: an in

vitro study

Fontes de luz de múltiplos picos podem melhorar as propriedades físicas e mecânicas de uma resina odontológica à base de

zircônia e diatomita: um estudo in vitro

Jucivaldo Martins GONÇALVES1 , Thalles Arievo Mota SALES1 , Cauã Santiago FIGUEIREDO2 , Rafael Pinto de MENDONÇA2 ,

Jefferson Pires da SILVA JÚNIOR2 , Tânia Mara da SILVA3 , Sérgio Eduardo de Paiva GONÇALVES2 , Hércules Bezerra DIAS4 

1 - Universidade Federal do Pará, Instituto de Ciências da Saúde, Faculdade de Odontologia. Belém, PA, Brazil.

2 - Universidade Estadual Paulista “Júlio de Mesquita Filho”, Instituto de Ciência e Tecnologia de São José dos Campos, Departamento de

Odontologia Restauradora. São José dos Campos, SP, Brazil.

3 - Universidade de Taubaté, Departamento de Odontologia. Taubaté, SP, Brazil.

4 - Universidade Federal do Pará, Instituto de Ciências da Saúde, Faculdade de Odontologia. Belém, PA, Brazil.

How to cite: Gonçalves JM, Sales TAM, Figueiredo CS, Mendonça RP, Silva Júnior JP, Silva TM, et al. Multi-peak light sources can

improve the physical and mechanical properties of a zirconia- and diatomite-based dental resin: an in vitro study. Braz Dent Sci.

2025;28(2):e4750. https://doi.org/10.4322/bds.2025.e4750

ABSTRACT

Objective: This study aimed to evaluate the physicomechanical properties of three resin composites—Zirconll

(Maquira), Applic (Maquira), and Opallis (FGM)—photoactivated with single-peak (Demi Plus; Kerr) and multi-

peak (Valo Cordless Grand; Ultradent; Bluephase N G4; Ivoclar Vivadent) light-curing units. The resins differed in

ller composition: Applic contains micronized barium-alumino-silicate glass and nanometric silica; Opallis includes

silanized barium-alumino-silicate glass and silicon dioxide nanoparticles; and Zirconll incorporates diatomite,

silica, and zirconium mixed oxide. Material and Methods: A total of 270 specimens were prepared to evaluate

the degree of conversion (DC), exural strength (FS), elastic modulus (ME), water sorption (SOR), and solubility

(SOL). Morphological and compositional characterization was performed using scanning electron microscopy (SEM)

and energy-dispersive spectroscopy (EDS). Data were analyzed using two-way ANOVA followed by Tukey’s post

hoc test (5%), after verication of normality (Shapiro-Wilk test). Results: Zirconll, when photoactivated with

the Bluephase unit, exhibited the highest FS and ME values and the lowest SOR and SOL rates, highlighting the

potential of innovative llers to enhance restoration durability. Although Opallis showed high DC values across all

groups, its mechanical properties were inferior. Conclusion: It can be concluded that the resin composition and the

selection of a light-curing unit with a spectrum and power compatible with the composite’s photoinitiator system

are essential to optimize the clinical performance and longevity of resin-based restorations.

KEYWORDS

Composite resins; Curing lights dental; Dental materials; Flexural strength; FTIR.

Resumo

Objetivo: Este estudo teve como objetivo avaliar as propriedades físico-mecânicas de três resinas compostas —

Zirconll (Maquira), Applic (Maquira) e Opallis (FGM) — fotoativadas com unidades de luz de pico único (Demi

Plus; Kerr) e de múltiplos picos (Valo Cordless Grand; Ultradent; Bluephase N G4; Ivoclar Vivadent). As resinas

diferem na composição das cargas: Applic contém vidro de bário-alumino-silicato micronizado e sílica nanométrica;

Opallis, vidro de bário-alumino-silicato silanizado e nanopartículas de dióxido de silício; e Zirconll, diatomita, sílica

e óxido misto de zircônio. Material e Métodos: Foram preparados 270 espécimes para avaliar grau de conversão

(DC), resistência à exão (FS), módulo de elasticidade (ME), sorção (SOR) e solubilidade (SOL). A caracterização

Braz Dent Sci 2025 Apr/Jun;28 (2): e4750

Gonçalves JM et al.

Multi-peak light sources can improve the physical and mechanical properties of a zirconia- and diatomite-based dental resin: an in vitro study

Gonçalves JM et al. Multi-peak light sources can improve the physical and

mechanical properties of a zirconia- and diatomite-based

dental resin: an in vitro study

morfológica e composicional foi realizada por microscopia eletrônica de varredura (MEV) e espectroscopia por

dispersão de energia (EDS). Os dados foram analisados por ANOVA de dois fatores e teste de Tukey (5%), após

vericação da normalidade (Shapiro-Wilk). Resultados: A resina Zirconll, fotoativada com Bluephase, apresentou

os melhores resultados em FS, ME e os menores índices de SOR e SOL, evidenciando o potencial de cargas inovadoras

para aumentar a durabilidade restauradora. Embora a Opallis tenha mostrado altos valores de DC, suas propriedades

mecânicas foram inferiores. Conclusão: Conclui-se que a composição da resina e a escolha de uma unidade de

fotoativação com espectro e potência compatíveis com o sistema fotoiniciador do compósito são essenciais para

otimizar o desempenho clínico e a longevidade das restaurações.

PALAVRAS-CHAVE

Resinas compostas; Lâmpadas de polimerização dentária; Materiais dentários; Resistência à exão; FTIR.

INTRODUCTION

Dental caries remains a global public health

issue, especially in low- and middle-income

countries, due to biological, behavioral, and

socioeconomic factors, as well as limited access

to dental services [1,2]. Secondary caries,

which occur around existing restorations, can

complicate treatment and increase costs for both

patients and health systems [3,4]. Therefore, the

longevity of restorations depends on the quality

of the restorative materials and the training of

dental professionals [3-5].

The strength of resin composites is directly

associated with the composition of their

llers and the type of light-curing unit (LCU)

employed [6-9]. To improve their mechanical

properties, particles such as diatomite and zirconia

have been incorporated into certain formulations

[10-14]. Diatomite is a porous silicate derived

from diatomaceous algae, characterized by

high porosity, large surface area, low density,

and good thermal stability [10-12]. Its lower

cost compared to other ller particles makes it

an economically viable alternative for dental

composites. Additionally, its porous structure

facilitates monomer penetration and interlocking

with the polymer matrix, contributing to a higher

degree of conversion and enhanced chemical

stability [10-12].

The incorporation of diatomite into dental

composites was rst reported around 2011 in

studies conducted by Wang et al. [12]; however,

these investigations primarily focused on the

effect of porous diatomite on ller content and

fracture morphology of resin-based composites,

rather than on evaluating their chemical and

mechanical properties. Despite its advantages,

diatomite presents some limitations. The most

notable is that its highly porous structure,

although beneficial for monomer infiltration,

may reduce the mobility of the surrounding

polymer network, thereby limiting the degree

of conversion under certain conditions [10-12].

Zirconia, in contrast, is a widely used ller

particle in dentistry due to its high mechanical

strength, exural resistance, surface hardness,

and thermal stability [13,14]. Its inclusion

in composites significantly contributes to

the structural reinforcement of the material,

enhancing resistance to wear and fracture [13,14].

However, since zirconia lacks porosity, it does not

substantially contribute to chemical interlocking

with the polymer matrix, serving predominantly

as a physical reinforcement agent [13,14].

Furthermore, advancements in light-curing

units (LCUs) play a crucial role in the quality

of photopolymerization [6,15,16]. Single-

peak LCUs (445–480 nm) efficiently activate

camphorquinone but exhibit limitations in

polymerizing alternative photoinitiators such as

TPO, BAPO, MAPO, and Ivocerin, which may result

in a lower degree of conversion (DC). In contrast,

multi-peak LCUs (380–550 nm) provide a broader

emission spectrum, leading to a higher DC and

improvements in properties such as mechanical

strength, water sorption, and solubility [17-19].

The degree of conversion, which reflects the

extent of monomer conversion into polymer,

is essential for the mechanical performance

and biocompatibility of resin-based materials,

influencing fracture resistance, hardness, and

chemical stability. A low DC can accelerate

material degradation by increasing water uptake

and reducing the longevity of restorations [17-22].

In this context, the present study aimed to

evaluate the physicomechanical properties of three

resin composites containing different types of ller

particles, polymerized using both single-peak and

multi-peak LCUs. The evaluated properties included

degree of conversion, exural strength, modulus

Braz Dent Sci 2025 Apr/Jun;28 (2): e4750

Gonçalves JM et al.

Multi-peak light sources can improve the physical and mechanical properties of a zirconia- and diatomite-based dental resin: an in vitro study

Gonçalves JM et al. Multi-peak light sources can improve the physical and

mechanical properties of a zirconia- and diatomite-based

dental resin: an in vitro study

of elasticity, water sorption, and solubility. The

experimental hypotheses tested were as follows:

(i) polymerization with multi-peak LCUs results

in a higher degree of conversion and superior

mechanical properties compared to single-peak

LCUs; and (ii) composites containing diatomite

exhibit lower water sorption and solubility values

compared to conventional composites.

MATERIALS AND METHODS

A total of 270 specimens were prepared

for this in vitro study. Of these, 90 were used

for the degree of conversion test, 90 for the

exural strength and elastic modulus test, and

90 for the sorption and solubility test (Figure 1).

Three commercially available resin composites

were evaluated, and for each combination of

composite and light-curing unit, 10 specimens

were fabricated (n = 10). The materials,

compositions and other relevant characteristics

are summarized in Table I. The specimens were

prepared in standardized 2 mm increments. Light

curing was performed using three different light-

curing units: Valo Cordless Grand (Ultradent;

1250 mW/cm2), Bluephase N G4 (Ivoclar

Vivadent; 1237 mW/cm2), and Demi Plus (Kerr;

1200 mW/cm2), each applied for 20 seconds.

Scanning electron microscopy and energy

dispersive spectroscopy

Surface and charge characterization were

performed using Scanning Electron Microscopy (SEM)

and Energy Dispersive Spectroscopy (EDS). Three

samples of each resin were prepared in 2 × 2 mm

dimensions using silicone molds. Each group was

Figure 1. Schematic representation of materials, equipment used, and experimental tests performed.

Table I - Resin composites used and their characteristics

RESINS COMPOSITION LOT

(APPLIC;

MAQUIRA)

(Maringá, Brasil)

Dimethacrylate groups,

catalysts, organic ﬁller, silicon

dioxide, sodium ﬂuoride,

ethanol, Carbopol, BHT and

iron oxide

266423

(OPALLIS; FGM)

(Joinville, Brasil)

Monomeric matrix containing

Bis (GMA), Bis (EMA), UDMA

and TEGDMA.

Inorganic Content: silanized

Barium-Alumino silicate

glass and silicon dioxide

nanoparticles, camphorquinone

as photoinitiator, accelerators,

stabilizers and pigments.

20921

(ZIRCONFILL;

MAQUIRA)

(Maringá, Brasil)

Bis – GMA, Bis-EMA, TEGDMA

and UDMA, Photoinitiator,

Diatomite, Silica, Mixed

Zirconia and Silica Oxide and

Pigments.

410623

Braz Dent Sci 2025 Apr/Jun;28 (2): e4750

Gonçalves JM et al.

Multi-peak light sources can improve the physical and mechanical properties of a zirconia- and diatomite-based dental resin: an in vitro study

Gonçalves JM et al. Multi-peak light sources can improve the physical and

mechanical properties of a zirconia- and diatomite-based

dental resin: an in vitro study

light-cured for 20 seconds with the respective light-

curing units (LCUs) used in this study, maintaining

a 2 mm distance between the LCU tip and the

sample surface.

Samples were mounted on metal stubs, sputter-

coated with a ~10 nm layer of gold, and analyzed

using a scanning electron microscope (Tescan

Mira 3; Tescan Orsay Holding) operating at 15 kV.

Images were acquired at 200× magnication, with

resolution automatically adjusted by the Tescan

Essence™ software. No filters or brightness/

contrast modications were applied.

Additionally, one sample of each resin,

prepared with the same dimensions, was sputter-

coated with carbon and mounted on a stub for

elemental analysis using EDS, conducted on the

same microscope under identical operational

conditions. All images were analyzed under

controlled conditions (22 ± 1 °C; 50-60% humidity)

using Tescan Essence™ software for morphological

interpretation and elemental distribution.

Degree of conversion

A total of 90 specimens were prepared

and divided into nine groups. The specimens

were molded using Teflon molds (5 mm in

diameter × 2 mm in height), with a polyester

strip placed on a glass slide beneath the mold. The

mold was lled with resin, covered with another

polyester strip and a glass coverslip, and light

digital pressure was applied to the coverslip to

ensure a smooth surface [15,18,19].

Prior to photopolymerization, the uncured

specimens were analyzed by Fourier Transform

Infrared Spectroscopy (FTIR; Perkin Elmer)

in attenuated total reflectance (ATR) mode,

with a resolution of 4 cm−1 over a spectral

range of 650–4000 cm−1. The analysis monitored

the conversion of carbon–carbon double bonds

(1638 cm−1) into single bonds (1608 cm−1) [18].

Photopolymerization was then performed

while the specimens remained in contact with the

ATR crystal. The light-curing units (LCUs) were

pre-calibrated using a radiometer (RD-7; ECEL)

to ensure accurate light output. Table II presents

the light intensity, irradiation sequence, and the

specic photopolymerizer used in all tests.

The LED units were positioned 2 mm

above and perpendicular to the horizontal

platform containing the ATR crystal. A spectrum

collector (Spectrum; Perkin Elmer) was used

to automatically acquire spectra during the

polymerization process. The degree of conversion

(DC) was calculated using the following equation,

based on the ratio of absorbance bands before

and after light polymerization:

( )

()

(1638 )

(1608 )

% 1 1 0 0

1638

1608

cured

DC x

uncured

−





= − 





(1)

Flexural strength and modulus of elasticity

Ten samples were prepared for each

group (n=90) using rectangular Teflon

molds (25×2×2 mm), in accordance with ISO

standards [23,24]. The resin was inserted in a

single increment, covered with a transparent

polyester strip and a glass coverslip, and light-

cured at three points (two at the top surface and

one at the bottom) for 20 seconds each. A scalpel

blade was used to remove surface irregularities

without damaging the samples.

Table II - LCU devices, power, energy density studied groups and number of tested specimens

Photopolymerizer Device power Energy density (J/cm2, 20 s) Resin groups Number of specimens

(Demi Plus; Kerr) 1200 mW/cm224 J/cm2

Applic-Demi (AD) 10

Applic-Bluephase (AB) 10

Applic-Valo (AV) 10

(Bluephase N G4;

Invoclar Vivadent) 1237 mW/cm224.74 J/mc2

Opallis-Demi (OD) 10

Opallis-Bluephase (OB) 10

Opallis-Valo (OV) 10

(Valo Cordless Grand;

Ultradent) 1250 mW/cm225 J/cm2

Zirconﬁll-Demi (ZD) 10

Zirconﬁll-Bluephase (ZB) 10

Zirconﬁil-Valo (ZV) 10

Braz Dent Sci 2025 Apr/Jun;28 (2): e4750

Gonçalves JM et al.

Multi-peak light sources can improve the physical and mechanical properties of a zirconia- and diatomite-based dental resin: an in vitro study

Gonçalves JM et al. Multi-peak light sources can improve the physical and

mechanical properties of a zirconia- and diatomite-based

dental resin: an in vitro study

The irradiance of each LCU was measured

using a radiometer (values in Table II). The

specimens were individually stored in Eppendorf

tubes containing distilled water and kept in

an oven at 37 °C for 24 hours prior to testing.

Mechanical properties were evaluated using a

three-point exural test performed on a universal

testing machine (EMIC DL-2000MF; Instron

Brazil) at a crosshead speed of 0.5 mm/min

with a 10 Kgf load cell. Flexural strength was

calculated based on the fracture load, and the

modulus of elasticity was derived from the load-

deection curves.

Sorption and solubility

To evaluate sorption and solubility, ten

specimens from each of the nine groups were

prepared (n=90) in accordance with ISO

4049:2019 [21,24]. The resin was inserted into

the mold in a single increment, covered with a

polyester strip and a glass coverslip, and light-

cured for 20 seconds on the upper surface. After

demolding, the bottom surface was polymerized

for the same duration. The irradiance of each LCU

was veried using a radiometer.

Sample thickness was measured with a

digital caliper (0.01 mm accuracy) to calculate

volume (mm3). The specimens were stored in

Eppendorf tubes inside a desiccator containing freshly

dried silica gel and weighed after 24 hours using

an analytical balance (XP204; Mettler Toledo,

0.00001 g accuracy). This cycle was repeated until

a constant mass (M1) was obtained. The specimens

were then immersed in 2 ml of distilled water at

37°C for 7 days. Every 24 hours, they were dried

with absorbent paper, weighed (M2 - sorption),

and returned to the water. After 28 days, they were

dried in the desiccator and weighed daily until

reaching a constant mass (M3 – solubility) [21,25].

Water sorption (SOR) and solubility (SOL) were

calculated using the following equations:

( )

SOR

−

(2)

( )

SOL

−

(3)

Experimental design

The experimental design followed a 3 × 3

factorial scheme, considering two independent

variables: the type of resin composite (Applic,

Zirconll, and Opallis) and the type of light-curing

unit (Demi Plus; Kerr, Valo Cordless Grand;

Ultradent, and Bluephase N G4; Ivoclar Vivadent),

resulting in nine experimental groups. The sample

size of 10 specimens per group was determined

based on previous studies in the literature that

employed similar experimental designs for

evaluating the physicomechanical properties

of resin composites [20-25]. These studies

demonstrated that this sample size is adequate

to detect statistically significant differences in

continuous variables when analyzed using two-

way ANOVA, as applied in the present study.

The Figure 1 summarizes the experiments

in a schematic representation of materials,

equipment used, and the tests performed.

Data analysis

After testing the data for normality using

the Shapiro–Wilk test, inferential analysis was

performed using two-way analysis of variance

(ANOVA) with two factors (resin composite

and light-curing unit). Tukey’s post hoc test

was applied for multiple comparisons at a

signicance level of 5%.

Figure 2. The magniﬁcations considered were (a) x200 for Applic resin; (b) x200 for Opallis resin; and (c) x200 for Zirconﬁll resin.

Braz Dent Sci 2025 Apr/Jun;28 (2): e4750

Gonçalves JM et al.

Multi-peak light sources can improve the physical and mechanical properties of a zirconia- and diatomite-based dental resin: an in vitro study

Gonçalves JM et al. Multi-peak light sources can improve the physical and

mechanical properties of a zirconia- and diatomite-based

dental resin: an in vitro study

Statistical analyses were conducted using

GraphPad Prism software (version 6.0, 2010; La

Jolla, CA, USA).

RESULTS

SEM and EDS

Figures 2 and 3 present the SEM and EDS

results for the evaluated resin composites. In

Figure 2, the micrographs reveal distinct surface

morphologies among the materials. Zirconfill

exhibited a more compact and homogeneous

surface, with reduced porosity and a uniform

distribution of filler particles, compared to

Applic and Opallis, which showed particle

agglomerates and topographical irregularities.

These morphological features help to explain

the superior mechanical performance observed

for Zirconll.

Figure 3 displays elemental mapping by

EDS, conrming the presence of silicon (Si) and

barium (Ba) in all formulations, while zirconium (Zr)

was identied exclusively in the Zirconll samples.

The even dispersion of elements observed in the

mapping supports the structural uniformity of the

material. The inclusion of these imaging analyses is

justied by their relevance in interpreting the ller

composition and its potential correlation with the

physical-mechanical properties evaluated.

According to the two-way ANOVA, the

resin composite had a statistically significant

effect on the degree of conversion (%), with

p = 0.0001 and F = 37.36. Photopolymerization

also had a significant impact (p = 0.0001;

F = 268.7), as did the interaction between factors

(p = 0.0001; F = 79.3). For exural strength,

both resin composite (p = 0.0001; F = 19.06) and

photopolymerization (p = 0.0009; F = 13.68)

showed statistically signicant differences.

Additionally, the interaction between factors

was also signicant (p = 0.0001; F = 21.26).

Regarding the modulus of elasticity, the effects

of resin composite (p = 0.0003; F = 17.82) and

photopolymerization (p = 0.0001; F = 16.57) were

statistically signicant, as well as their interaction

(p = 0.0089; F = 5.641). Water sorption

exhibited statistically signicant differences for

both resin composite (p = 0.0174; F = 4.260) and

photopolymerization (p = 0.0001; F = 10.86).

However, the interaction between factors was not

statistically signicant (p = 0.0591). For water

solubility, resin composite (p = 0.0137; F = 4.529)

and photopolymerization (p = 0.0001; F = 10.49)

had statistically signicant effects. However, the

interaction between factors was not signicant

(p = 0.1052).

Degree of conversion

Table III presents the mean values and

standard deviations of the degree of conversion

(DC%) for the resin composites evaluated,

along with the statistical analysis performed

using the Tukey test. It was observed that the

Zirconfill resin, when photoactivated with

the Demi device, exhibited the lowest degree

of conversion (35.4 ± 4.3%), which was

significantly lower than the values obtained

with the third-generation devices Bluephase

(59.1 ± 1.8%) and Valo (60.3 ± 2.6%) (p<0.05).

For the Applic resin, a similar behavior was

noted, with a significantly lower DC when

cured with the Demi device (47.5 ± 1.9%)

compared to the Bluephase (60.0 ± 1.1%) and

Valo (57.9 ± 1.1%), between which no statistically

signicant difference was observed. In contrast,

the Opallis resin demonstrated high DC values

across all light-curing units, with no statistically

signicant differences among them (p>0.05).

Figure 3. Elementary characterization of the EDS. Particle sizes

ranged from ~10 μm to up to 5 μm and the elemental distribution

showed the presence of barium, silicon, zirconium, aluminum, carbon

and oxygen.

Table III - Mean (SD) and Tukey Test for degree of conversion (%), of

the resin composites evaluated

Demi Bluephase Valo

Zirconﬁll 35.4 (4.3) Cb 59.1 (1.8) Aa 60.3 (2.6) Aa

Applic 47.5 (1.9) Bb 60.0 (1.1) Aa 57.9 (1.1) Aa

Opallis 60.9 (1.7) Aa 59.8 (1.0) Aa 59.9 (1.0) Aa

Capital letters refer to columns; lowercase letters refer to lines;

diﬀerent letters present statistically signiﬁcant diﬀerences (p<0.05).

Braz Dent Sci 2025 Apr/Jun;28 (2): e4750

Gonçalves JM et al.

Multi-peak light sources can improve the physical and mechanical properties of a zirconia- and diatomite-based dental resin: an in vitro study

Gonçalves JM et al. Multi-peak light sources can improve the physical and

mechanical properties of a zirconia- and diatomite-based

dental resin: an in vitro study

The two-way ANOVA analysis (Table IV)

revealed statistically significant differences

between the different resin composites (p=0.0001)

and between the different photoactivation

protocols (p=0.0001). Moreover, a signicant

interaction between the factors “resin type” and

“light-curing unit” was detected (p=0.0001),

indicating that the degree of monomer conversion

varied according to the resin composite evaluated.

Flexural strength and modulus of elasticity

The exural strength and modulus of elasticity

of the evaluated resin composites were signicantly

inuenced by both the type of resin and the light-

curing unit used (Table V). Zirconll exhibited the

highest exural strength and modulus of elasticity

values, particularly when photoactivated with the

Bluephase device. The Applic resin demonstrated

reduced flexural strength when cured with

Bluephase compared to the Demi unit, whereas

Opallis showed the lowest values for mechanical

properties among the composites, regardless of

the light-curing unit employed.

Sorption and solubility

Table VI presents the mean values and

standard deviations for the percentage of water

sorption and solubility observed in the studied

groups. The highest sorption and solubility values

were recorded in the Opallis group (microhybrid)

when polymerized with the Bluephase device,

leading to more significant changes compared

to the Valo device, which demonstrated greater

stability. This suggests that the light-curing unit

inuenced polymerization efciency by promoting

the formation of longer polymer chains and

reducing intermolecular spaces within the matrix.

Some degree of polymerization was

achieved with the Demi device. However, the

curing was insufcient to convert most of the

monomers, resulting in a higher number of

residual monomers, which, in turn, increased

water absorption. Notably, the presence of

zirconia particles in the Zirconll resin appeared

to contribute to maintaining its properties,

regardless of the light-curing unit used.

Table IV - Result of the 2-way ANOVA test for conversion degree (%)

Source DF SS MS F p

Resin 2 567.2 283.6 37.36 0.0001*

Photoactivation 2 1340 669.9 268.7 0.0001*

Interaction 4 1093 273.1 79.3 0.0001*

Residue 16 55.11 3.444

*Statistically signiﬁcant diﬀerences (p<0.05). Note: DF (Degrees of Freedom), SS (Sum of Squares), MS (Mean Square), F F-value and

p ( p-value).

Table V - Mean (SD) and Tukey Test for ﬂexural strength and

modulus of elasticity, of the resin composites evaluat

Flexural strength

Zirconﬁll 149.79

(11.5) Ab

176.02

(9.2) Aa

136.01

(7.3) Ab

Applic 158.51

(14.2) Aa

120.65

(10.9) Bb

143.69

(11.5) Aa

Opallis 135.51

(7.83) Ba

136.58

(15.8) Ba

127.53

(11.9) Aa

Modulus of elasticity

Zirconﬁll 3.42

(0.22) Ab

3.73

(0.28) Aa

3.11

(0.26) Ac

Applic 2.85

(0.45) Bb

3.53

(0.37) Aa

3.04

(0.24) Ab

Opallis 2.84

(0.25) Bb

3.16

(0.19) Ba

3.07

(0.23) Aa

Capital letters refer to columns; lowercase letters refer to lines;

diﬀerent letters show statistically signiﬁcant diﬀerences (p<0.05).

Table VI - Mean (SD) and Tukey Test for water sorption and solubility

(μg/mm3) of the resin composites evaluated

Sorption

Zirconﬁll 0.157

(0.01) Aa

0.159

(0.008) Aa

0.153

(0.01) Aa

Applic 0.163

(0.01) ACa

0.157

(0.005) Aab

0.152

(0.01) Ab

Opallis 0.169

(0.01) BCa

0.171

(0.01) Ba

0.151

(0.01) Ab

Solubility

Zirconﬁll 0.157

(0.01) Aa

0.158

(0.008) Aa

0.152

(0.01) Aa

Applic 0.162

(0.01) ACa

0.156(0.005)

0.151

(0.01) Aa

Opallis 0.168

(0.01) BCa

0.170

(0.01) Ba

0.151

(0.01) Ab

Capital letters refer to columns; lowercase letters refer to lines;

diﬀerent letters show statistically signiﬁcant diﬀerences (p<0.05).

Braz Dent Sci 2025 Apr/Jun;28 (2): e4750

Gonçalves JM et al.

Multi-peak light sources can improve the physical and mechanical properties of a zirconia- and diatomite-based dental resin: an in vitro study

Gonçalves JM et al. Multi-peak light sources can improve the physical and

mechanical properties of a zirconia- and diatomite-based

dental resin: an in vitro study

DISCUSSION

The selection of resin composites for

restorative procedures should prioritize their

physical-mechanical properties in order to

optimize the quality and durability of the

restorations [26]. The type of ller used in the

resins directly inuences their handling, aesthetic

appearance, and mechanical properties [15,17].

In this study, the characterization of the resin

components identified zirconium, barium,

and silicon, with barium glass and diatomite

being the main constituents of the filler in

Zirconll resin. The type and amount of ller

inuence the degree of conversion (DC), exural

strength (FS), sorption, and solubility of the resin

composites [10,15,17,27-30].

The findings of this study indicate that

resin composites containing diatomite, when

photoactivated using second-generation

light-curing units (LCUs), exhibit a degree of

conversion (DC) below 40% (Table III). The

presence of diatomite and zirconia appears

to hinder effective light penetration, thereby

reducing energy delivery and monomer conversion

— an effect that contrasts with ndings reported

in previous studies [10,12,14]. Although specic

studies evaluating the direct effect of

diatomite

or zirconia on light transmission are limited, it

is well established that highly opaque llers and

materials with elevated refractive indices can

impede light propagation, negatively affecting

polymerization efciency [18,29,30]. Additionally,

the alternative photoinitiators incorporated in

these formulations are not efciently activated by

second-generation LCUs [9,10,27]. In contrast,

third-generation LCUs, which are characterized

by higher energy density, were capable of

overcoming these limitations and promoting

improved polymer conversion.

In addition to classifying light-curing units

(LCUs) based on their emission spectra (single-peak

and multi-peak), it is essential to consider the energy

density delivered by each device. Energy density,

dened as the product of irradiance (mW/cm

) and

exposure time (s), represents the radiant exposure

received by the resin and plays a critical role in

determining polymerization efficiency [28-30].

In this study, the calculated energy densities were

24 J/cm

for Demi, 24.74 J/cm

for Bluephase,

and 25 J/cm

for Valo. These values are within the

range of 20–30 J/cm

, which is considered adequate

for effective polymerization of 2-mm composite

layers according to previous studies [20,28-30].

Despite the similar energy densities provided

by the different devices, differences in emission

spectra and the compatibility with the photoinitiator

systems impacted the degree of conversion and

other physical-mechanical properties observed.

Therefore, evaluating only irradiance or exposure

time individually is insufcient — both the total

energy density and spectral compatibility must be

considered to accurately interpret polymerization

outcomes [20,28,30].

Diatomite has been reported to enhance

the physical and mechanical properties of resin

composites, thereby increasing the longevity of

restorations [10,12]. The literature suggests that

resins containing diatomite can achieve a DC of

approximately 60% immediately after multi-peak

light-curing, increasing to around 80% after

seven days [10,11]. Most studies have focused

on evaluating DC using multi-peak units [10,12].

This study showed that Opallis resin

achieved a DC greater than 58%, regardless

of the type of LCU used. This elevated degree

of conversion may be attributed to the smaller

ller particle size (~0.5 µm), lower ller volume,

and the composition of the organic matrix, all of

which facilitates light penetration [28,29]. The

combination of UDMA and TEGDMA promotes

the formation of a higher number of crosslinks

and results in a greater DC compared to systems

based on BisGMA and TEGDMA, contributing to

the superior performance observed in Opallis.

In contrast, the Applic resin, when light-

cured with the Demi device, exhibited a DC below

50%. Although there is no ideal DC threshold

for clinical performance, the literature suggests

a range of 55–65% for occlusal restorative

layers [27,29,30]. The reduced DC observed

in the Applic may be attributed to its higher

ller content (77–79%) and larger particle size

(>0.7 µm), both of which hinder monomer

conversion when using low-spectral-range

sources such as single-peak LCUs. Conversely,

Opallis, with its lower ller content, consistently

demonstrated DC values above 59%, reinforcing

previous ndings regarding the inuence of ller

content, spectral compatibility, and LCU power

on polymerization efciency [19,28].

In this study, despite the low degree of

conversion observed in resins cured with the

single-peak light-curing unit, the FS and ME values

Braz Dent Sci 2025 Apr/Jun;28 (2): e4750

Gonçalves JM et al.

Multi-peak light sources can improve the physical and mechanical properties of a zirconia- and diatomite-based dental resin: an in vitro study

Gonçalves JM et al. Multi-peak light sources can improve the physical and

mechanical properties of a zirconia- and diatomite-based

dental resin: an in vitro study

met the requirements of ISO 4049:2019 and

were consistent with findings from previous

studies [10,22,24,27]. The resin containing

diatomite and a higher volume of inorganic ller

exhibited elevated exural strength and modulus of

elasticity values, indicating that diatomite reinforces

the mechanical properties of the resin composites,

as previously reported [10-12]. The mechanical

properties of resin composites are closely associated

with the DC, playing a crucial role in the long-term

success of restorations [6,9,17,22]. The correlation

between ller content and its inuence on FS and

ME is well established, resulting both from stress

transfer between filler particles and the resin

matrix, and from the quality of adhesion between

these components [9,31,32]. However, some

authors have reported a low correlation between

the ller volume and FS [32-34].

The high FS and ME values observed for

the Zirconll resin may be attributed not only

to the greater amount of ller particles, but also

to the reinforcing effect of diatomite, which can

deect cracks and generate frictional forces that

enhance the material’s strength [10,12]. Several

studies support the relationship between ller

loading and improved mechanical properties

in resin-based composites [6,9,17,20,27,33].

Additionally, the composition of the organic

matrix plays a significant role in mechanical

performance [9,34,35]. The presence of Bis-GMA

and Bis-EMA, while increasing resin viscosity,

promotes higher crosslink density and contributes

to enhanced mechanical properties [9,34,35].

The results of this study demonstrated that

resins containing traditional llers exhibited

lower exural strength (FS) and modulus of

elasticity (ME) compared to Zirconll, even in

the presence of reinforcing monomers such as

Bis-GMA and Bis-EMA. Applic resin, when cured

with the Bluephase device, presented values

of approximately 120.65 MPa, while Opallis

resin cured with the Valo unit showed values

around 127.53 MPa. Both exhibited the lowest

FS values among the groups tested (Table V).

Nevertheless, all tested resins complied with the

ISO 4049:2019 standards [24].

The type of LCU appeared to influence

only the water sorption behavior of resins with

conventional ller compositions. In contrast,

Zirconll resin showed no signicant differences

in sorption between specimens cured with

single-peak and multi-peak LCUs. This stability

may be related to the size and type of inorganic

particles in Zirconll’s composition. Previous

studies have indicated that the incorporation of

zirconia and silica particles into resin composites

can enhance hydrolytic stability by reducing

water sorption and limiting the diffusion of

water molecules into the polymer matrix, thus

contributing to the long-term preservation of

mechanical properties [10,11,25]. The sorption

resistance observed in Zirconfill has been

reported previously, reinforcing the potential of

its ller formulation to enhance the material’s

hydrolytic stability [10]. Since water sorption is

associated with chemical degradation through

the release of residual monomers, the reinforcing

particles in Zirconfill may help prevent this

degradation, preserving the structural integrity

of the polymer matrix [10,25].

The elevated solubility values observed in the

Opallis resin photoactivated with the Bluephase

device may be attributed to the release of residual

free monomers, additives, and ller particles. This

phenomenon is likely related to the hydrophilic

nature and high mobility of these components,

as well as the presence of TEGDMA in the resin

composite used in this study [14,25,28,31]. A low

degree of conversion can also lead to a higher

concentration of unreacted monomers, which

are prone to dissolution in humid environments,

leading to material degradation and potentially

compromising the longevity of the restoration.

Conversely, groups cured with multi-peak LCUs

exhibited the lowest solubility values, likely due

to the higher energy output of third-generation

units, which deliver greater radiant exposure to

the resin materials [25,28].

Based on the ndings of this study, the rst

experimental hypothesis was generally conrmed.

The Zirconll and Applic resin composites, when

photoactivated with multi-peak light-curing

units, exhibited higher degree of conversion

and superior mechanical properties (exural

strength and elastic modulus) compared to those

cured with a single-peak unit. However, for the

Opallis resin, the type of light-curing unit did not

signicantly inuence the degree of conversion,

indicating that this effect also depends on

the specific composition of each composite.

Regarding the second hypothesis, it was partially

conrmed. Zirconll demonstrated lower water

sorption and solubility values compared to

the conventional Opallis composite, especially

when multi-peak light-curing units were used.

Braz Dent Sci 2025 Apr/Jun;28 (2): e4750

Gonçalves JM et al.

Multi-peak light sources can improve the physical and mechanical properties of a zirconia- and diatomite-based dental resin: an in vitro study

Gonçalves JM et al. Multi-peak light sources can improve the physical and

mechanical properties of a zirconia- and diatomite-based

dental resin: an in vitro study

However, the curing device also affected these

properties, highlighting the importance of

compatibility between the photoinitiator system,

the inorganic ller characteristics, and the light

source employed. Overall, the results of this

study emphasize that both the type of ller and

the photoactivation protocol directly inuence

the physicomechanical behavior and potential

clinical longevity of composite restorations.

These findings further underscore the

need for careful selection of light-curing units

according to the resin composite formulation

to ensure optimal clinical outcomes. Multi-

peak LCUs proved to be more effective. Multi-

peak LCUs proved to be more effective in

activating alternative photoinitiators, especially

in composites with high inorganic ller content,

such as those containing diatomite and zirconia.

The high exural strength and elastic modulus

values observed in these materials, even under

less favorable curing conditions, indicate their

potential for use in areas subject to greater

mechanical demands [10,12,18,21,25,28,31].

Moreover, the superior mechanical stability

and lower sorption and solubility indices

associated with functional fillers suggest

additional benets in more challenging clinical

environments [10,25,26,31].

Despite these promising results, some

limitations of this study should be acknowledged.

First, the polymerization time of 20 seconds

used for all LCUs, particularly the single-peak

device, may have been insufficient to fully

cure resin composites with more complex ller

compositions, such as those containing diatomite

and zirconia. This may have affected the degree

of conversion and, consequently, the physical-

mechanical properties. Additionally, although

the porous structure of diatomite may facilitate

monomer inltration and interfacial bonding,

the restricted mobility of the polymer network

in the presence of such llers could also limit

the extent of polymerization [10,12]. It is also

important to note that the ndings are based on

in vitro conditions and may not fully replicate

the behavior of these materials in the oral

environment, where thermal, mechanical, and

chemical challenges are constant. Finally, the

study did not consider different curing times,

which may inuence polymerization outcomes.

Future studies should investigate this variable

to conrm and expand the applicability of the

present ndings.

CONCLUSION

Within the limitations of this study,

it can be concluded that the type of resin

composite and the light-curing unit signicantly

influenced the degree of conversion, flexural

strength, elastic modulus, water sorption,

and solubility of the evaluated materials. The

Zirconfill resin composite, particularly when

photoactivated with the Bluephase multi-

peak device, demonstrated the most favorable

physicomechanical performance, achieving the

highest values of exural strength and elastic

modulus, as well as lower water sorption and

solubility compared to the other composites.

Although Zirconll exhibited a lower degree of

conversion when polymerized with the single-

peak Demi Plus device, the use of multi-peak units

effectively optimized its polymerization. The

Applic resin also beneted from photoactivation

with multi-peak devices, whereas Opallis resin,

despite achieving high degrees of conversion

regardless of the device used, exhibited lower

mechanical properties. These ndings highlight

the importance of selecting composites with

optimized inorganic llers and using light-curing

devices compatible with the photoinitiator

systems and matrix characteristics to enhance

the clinical performance and longevity of resin

composite restorations.

Acknowledgements

The authors acknowledge the use of the

facilities at LABNANO-AMAZON/UFPA and at

LIPq - Laboratório Integrado de Pesquisa em

Odontologia Restauradora, ICT-UNESP - São

José dos Campos.

Author’s Contributions

JMG: Conceptualization, Investigation,

Writing – Original Draft Preparation, Validation,

Visualization. TAMS: Investigation, Writing –

Original Draft Preparation, Visualization. CSF:

Investigation, Visualization. RPM: Investigation,

Resources, Writing – Original Draft Preparation,

Visualization. JPSJ: Investigation, Formal Analysis,

Resources, Writing – Original Draft Preparation,

Visualization. TMS: Investigation, Formal Analysis,

Resources, Writing – Original Draft Preparation,

Writing – Review & Editing, Visualization. SEPG:

Investigation, Formal Analysis, Resources, Writing

– Original Draft Preparation, Writing – Review &

Braz Dent Sci 2025 Apr/Jun;28 (2): e4750

Gonçalves JM et al.

Multi-peak light sources can improve the physical and mechanical properties of a zirconia- and diatomite-based dental resin: an in vitro study

Gonçalves JM et al. Multi-peak light sources can improve the physical and

mechanical properties of a zirconia- and diatomite-based

dental resin: an in vitro study

Editing, Visualization. HBD: Investigation, Formal

analysis, Project Administration, Resources,

Supervision, Writing – Original Draft Preparation,

Writing – Review & Editing, Visualization.

Conict of Interest

The authors have no proprietary, nancial,

or other personal interest of any nature or kind

in any product, service, and/or company that is

presented in this article.

Funding

The authors would like to thank the Federal

University of Pará (PROPESP-UFPA) for the

nancial support (PARC 2023 - IC) to carry out

the research (PRO 6433-2023).

Regulatory Statement

This study was conducted in accordance with

all the provisions of the local research

subjects oversight committee guidelines and

policies: no human or animals was used in this

research.

REFERENCES

1. Moharrami M, Farmer J, Singhal S, Watson E, Glogauer

M, Johnson AEW,etal. Detecting dental caries on oral

photographs using artificial intelligence: a systematic review.

Oral Dis. 2024;30(4):1765-83. http://doi.org/10.1111/odi.14659.

PMid:37392423.

2. Crescente LG, Gehrke GH, Santos CM. Mudanças da

prevalência de dentes permanentes cariados no Brasil e em

países de renda média-alta nos anos 1990 e 2017. Cien Saude

Colet. 2022;27(3):1181-90. http://doi.org/10.1590/1413-

81232022273.46812020. PMid:35293454.

3. Bhadila GY, Baras BH, Balhaddad AA, Williams MA, Oates

TW, Weir MD,etal. Recurrent caries models to assess dental

restorations: a scoping review. J Dent. 2023;136:104604. http://

doi.org/10.1016/j.jdent.2023.104604. PMid:37419382.

4. Nedeljkovic I, De Munck J, Vanloy A, Declerck D, Lambrechts P,

Peumans M,etal. Secondary caries: prevalence, characteristics,

and approach. Clin Oral Investig. 2020;24(2):683-91. http://doi.

org/10.1007/s00784-019-02894-0. PMid:31123872.

5. Ávila NNM, Bottezini PA, Nicoloso GFN, Araújo FB, Ardenghi TM,

Lenzi TL,etal. Prevalence of defective restorations and factors

associated with re‐intervention in primary teeth: a retrospective

university‐based study. Int J Paediatr Dent. 2019;29(5):566-72.

http://doi.org/10.1111/ipd.12493. PMid:30860303.

6. Marović D, Daničić P, Bojo G, Par M, Tarle Z. Monowave vs. polywave

light - curing units: effect on light transmission of composite without

alternative photoinitiators. Acta Stomatol Croat. 2024;58(1):30-8.

http://doi.org/10.15644/asc58/1/3. PMid:38562217.

7. Peres TS, Oliveira HLQ, Leyton C, Tereza M, Carlo HL, Price

RB,etal. Effect of four different mono and multi-wave light-

curing units on the Knoop hardness of veneer resin composites.

Dent Mater. 2024;40(1):80-9. http://doi.org/10.1016/j.

dental.2023.10.019. PMid:37919111.

8. Siqueira BDPS, Santos JN, Lima LS, Vieira TV, Lima AF,

Gonçalves LS. Como as características dos LEDs de segunda

e terceira geração podem influenciar a dureza de compósitos

restauradores: uma revisão da literatura. Rev Fac Odontol.

2021;26(2):299-312. http://doi.org/10.5335/rfo.v26i2.13031.

9. Cilingir A, Ozsoy A, Mert Eren M, Behram O, Dikmen B, Ozcan

M. Mechanical properties of bulk-fill versus nanohybrid

composites: effect of layer thickness and application protocols.

Braz Dent Sci. 2019;22(2):234-42. http://doi.org/10.14295/

bds.2019.v22i2.1719.

10. Jordão I, Zanini M, Guarda M, Fronza B, Consani S, Pinheiro

I,etal. Diatomite filler for resin composites application:

a new approach for materials improvement. Res Soc Dev.

2022;11(16):e268111637738. http://doi.org/10.33448/rsd-

v11i16.37738.

11. Regis M, Lima I, Pinto T, Medeiros HP, Oliveira HKC. Possibilities

of the use of diatomaceous earth in the composition

of dental materials: integrative review. Res Soc Dev.

2021;10(16):e521101623846. http://doi.org/10.33448/rsd-

v10i16.23846.

12. Wang H, Zhu M, Li Y, Zhang Q, Wang H. Mechanical properties

of dental resin composites by co-filling diatomite and nanosized

silica particles. Mater Sci Eng C. 2011;31(3):600-5. http://doi.

org/10.1016/j.msec.2010.11.023.

13. Shelar P, Abdolvand H, Butler S. On the behaviour of zirconia-

based dental materials: a review. J Mech Behav Biomed Mater.

2021;124:104861. http://doi.org/10.1016/j.jmbbm.2021.104861.

PMid:34600431.

14. Hong G, Yang J, Jin X, Wu T, Dai S, Xie H,etal. Mechanical

properties of nanohybrid resin composites containing various

mass fractions of modified zirconia particles. Int J Nanomedicine.

2020;15:9891-907. http://doi.org/10.2147/IJN.S283742.

PMid:33328732.

15. Cardoso IO, Machado AV, Teixeira D, Basílio FC, Marletta A,

Soares P. Influence of different cordless light-emitting-diode

units and battery levels on chemical, mechanical, and physical

properties of composite resin. Oper Dent. 2020;45(4):377-86.

http://doi.org/10.2341/19-095-L. PMid:31794341.

16. Mauricio F, Medina J, Vilchez L, Sotomayor O, Muricio-Vilchez C,

Mayta-Tovalino F. Effects of different light-curing modes on the

compressive strengths of nanohybrid resin-based composites:

a comparative in vitro study. J Int Soc Prev Community Dent.

2021;11(2):184-9. http://doi.org/10.4103/jispcd.JISPCD_423_20.

PMid:34036081.

17. Boeira PO, Kinalski MA, dos Santos MBF, de Moraes RR, Lima

GS. Polywave and monowave light-curing units effects on

polymerization efficiency of different photoinitiators. Braz

Dent Sci. 2021;24(4):1-9. http://doi.org/10.14295/bds.2021.

v24i4.2661.

18. Nikhil V, Varshney I, Jha P. Effect of monowave and polywave

light curing on the degree of conversion and microhardness of

composites with different photoinitiators: an in vitro study. J

Conserv Dent. 2022;25(6):661-5. http://doi.org/10.4103/jcd.

jcd_223_22. PMid:36591587.

19. Tsuzuki F, de Castro-Hoshino L, Lopes L, Sato F, Baesso M,

Terada R. Evaluation of the influence of light-curing units on

the degree of conversion in depth of a bulk-fill resin. J Clin Exp

Dent. 2020;12(12):e1117-23. http://doi.org/10.4317/jced.57288.

PMid:33282131.

20. Farzad A, Kasraei S, Haghi S, Masoumbeigi M, Torabzadeh

H, Panahandeh N. Effects of 3 different light-curing units

on the physico-mechanical properties of bleach-shade resin

Braz Dent Sci 2025 Apr/Jun;28 (2): e4750

Gonçalves JM et al.

Multi-peak light sources can improve the physical and mechanical properties of a zirconia- and diatomite-based dental resin: an in vitro study

Gonçalves JM et al. Multi-peak light sources can improve the physical and

mechanical properties of a zirconia- and diatomite-based

dental resin: an in vitro study

Date submitted: 2025 Mar 31

Accept submission: 2025 May 27

Hércules Bezerra Dias

(Corresponding address)

Universidade Federal do Pará, Instituto de Ciências da Saúde, Faculdade de

Odontologia, Belém, PA, Brazil.

Email: herculesdias@ufpa.br

composites. Restor Dent Endod. 2022;47(1):e9. http://doi.

org/10.5395/rde.2022.47.e9. PMid:35284327.

21. Atalı PY, Kaya BD, Özen AM, Tarçın B, Şenol AA, Bayraktar ET,etal.

Assessment of micro-hardness, degree of conversion, and flexural

strength for single-shade universal resin composites. Polymers.

2022;14(22):4987. http://doi.org/10.3390/polym14224987.

PMid:36433113.

22. Borges ALS, Borges AB, Barcellos DC, Saavedra GDSFA, Paes

TJDA Jr, Rode SM. Avaliação da resistência flexural e módulo

de elasticidade de diferentes resinas compostas indiretas. Rev

Pós-Grad. 2012;19(2):50-6.

23. Özduman ZC, Oglakci B, Bagis DMH, Temel BA, Dalkilic EE.

Comparison of a nanofiber-reinforced composite with different

types of composite resins. Polymers. 2023;15(17):3628. http://

doi.org/10.3390/polym15173628. PMid:37688254.

24. International Organization for Standardization. ISO 4049:2019:

dentistry: polymer-based restorative materials. Geneva: ISO;

2019.

25. Maia KMFV, Rodrigues FV, Damasceno JE, Ramos RVC, Martins

VL, Lima MJP,etal. Water sorption and solubility of a nanofilled

composite resin protected against erosive challenges. Braz Dent

Sci. 2019;22(1):46-54. http://doi.org/10.14295/bds.2019.v22i1.1660.

26. Strini BS, Marques JFL, Pereira R, Sobral-Souza DF, Pecorari VGA,

Liporoni PCS,etal. Comparative evaluation of bulk-fill composite

resins: knoop microhardness, diametral tensile strength and

degree of conversion. Clin Cosmet Investig Dent. 2022;14:225-

33. http://doi.org/10.2147/CCIDE.S376195. PMid:35957701.

27. Tapety CM, Carneiro YK, Chagas YM, Souza LC, Souza NO,

Valadas LA. Degree of conversion and mechanical properties

of a commercial composite with an advanced polymerization

system. Acta Odontol Latinoam. 2023;36(2):112-9. http://doi.

org/10.54589/aol.36/2/112. PMid:37776508.

28. Werlang J, Dalfovo R, Neiva I, Obici A. Atenuação da intensidade

de luz e profundidade de polimerização de resinas compostas.

Arq Odontol. 2013;49(1):12-8.

29. Hyun HK, Christoferson CK, Pfeifer CS, Felix C, Ferracane JL.

Effect of shade, opacity and layer thickness on light transmission

through a nano-hybrid dental composite during curing. J Esthet

Restor Dent. 2017;29(5):362-7. http://doi.org/10.1111/jerd.12311.

PMid:28628735.

30. AlShaafi MM. Factors affecting polymerization of resin-based

composites: a literature review. Saudi Dent J. 2017;29(2):48-58.

http://doi.org/10.1016/j.sdentj.2017.01.002. PMid:28490843.

31. Silva TM, Petrucelli NF, Mendonça RP, Silva JP Jr, Campos TMB,

Gonçalves SEP. Impact of photoinitiator quality on chemical-

mechanical properties of dental adhesives under different

light intensities. Braz Dent Sci. 2023;26(1):e3704. http://doi.

org/10.4322/bds.2022.e3704.

32. Goracci C, Cadenaro M, Fontanive L, Giangrosso G,

Juloski J, Vichi A,etal. Polymerization efficiency and

flexural strength of low-stress restorative composites.

Dent Mater. 2014;30(6):688-94. http://doi.org/10.1016/j.

dental.2014.03.006. PMid:24703547.

33. Park JK, Lee GH, Kim JH, Park MG, Ko CC, Kim HI,etal. Polymerization

shrinkage, flexural and compression properties of low-shrinkage

dental resin composites. Dent Mater J. 2014;33(1):104-10. http://

doi.org/10.4012/dmj.2013-126. PMid:24492120.

34. Frauscher KE, Ilie N. Depth of cure and mechanical properties of

nano-hybrid resin-based composites with novel and conventional

matrix formulation. Clin Oral Investig. 2012;16(5):1425-34. http://

doi.org/10.1007/s00784-011-0647-3. PMid:22134667.

35. Moezzyzadeh M. Evaluation of the compressive strength of

hybrid and nanocomposites. J Dent Sch. 2012;30(1):24-9.