Loading

JSM Dentistry

Effect of Light Curing Tip Distance and Immersion Media on the Degree of Conversion, Sorption and Solubility of Methacylate and Silorane-Based Composites

Research Article | Open Access | Volume 1 | Issue 2

  • 1. Department of Restorative Dentistry, Operative Dentistry Area, Minas Gerais, Brazil
  • 2. Department of Social Dentistry, Department of Restorative Dentistry, Operative Dentistry Area, University of Campinas, Piracicaba, São Paulo, Brazil
  • 3. Department of Social Dentistry, Statistical Area, University of Campinas, Piracicaba, São Paulo, Brazil
  • 4. Department of Restorative Dentistry, Operative Dentistry Area, University of Campinas, Piracicaba, São Paulo, Brazil
+ Show More - Show Less
Corresponding Authors
Diogo de Azevedo Miranda, Department of Restorative Dentistry, Faculty of medical sciences and health of Juiz de Fora - SUPREMA, Juiz de Fora – MG, Brazil,
Abstract

The purpose of this study in vitro was evaluate the degree of conversion (DC%), sorption (Sp) and solubility (Sl) of a methacrylate composite (Filtek™ Z250) and silorane-based composite (Filtek™ P90) cured in three curing tip distances (0 mm, 3 mm and 6 mm) with LED of second generation and immersed in artificial saliva (AS), Plax FeshMint (PFM), Plax Alcohol-Free (PAF) and Plax Whitening (PW). The methodology was based on the ISO 4049/2009 standard and five repetitions (n=5) were made for each group. Specimens (6mm in diameter and 1mm thick) were prepared and initially the degree of conversion (DC%) of discs was obtained by using an FT-IR spectrometer. After, the specimens were placed in a desiccator at 37ºC and to be weighed until a constant mass (m1 ) was obtained. The discs were immersed separately into the 4 media for 30 days. Twice a day, for two minutes, the samples were immersed in 2 ml of three mouthrinses. A control group was maintained in artificial saliva. After the period the discs was reweighed (m2 ). The reconditioning in the desiccator was done until a constant mass (m3 ) was obtained. The dates of DC% were analyzed by analysis of variance (ANOVA) in split plots and methacrylate-based composite showed significant higher DC than silorane-based composite and there is no statistical difference in DC between top and bottom surfaces. The sorption data were submitted to three-way ANOVA and Tukey’s Test at a 5% level of significance and the rate of sorption-based composite silorane (P90) was significantly lower than the methacrylate-based composite (Z250). Moreover, the artificial saliva did not affect the increase in rate of sorption in any of the photoactivation distances. In 3 mm and 6 mm light distance, the mouthwash Plax Whitening caused the increase of sorption for the two composites. The solubility date were analyzed by Kruskal-Wallis’s Test (p=0,05) and Dunn’s Test, since a non-normal date distribuition was observed. The values were negative, which means that there was mass gain. It may be concluded that the curing tip distance affect the degree of conversion and sorption only when cured to 6mm, however not influenced by the type of mouthwash. The solubility test demonstrated negative data, masking the real solubility..

Keywords


•    Composite
•    Solubility
•    Sorption

Citation

de Azevedo Miranda D, Pini NP, Bovi Ambrosano GM, Baggio Aguiar FH, Leite Lima DAN, et al. (2013) Effect of Light Curing Tip Distance and Immersion Media on the Degree of Conversion, Sorption and Solubility of Methacylate and Silorane-Based Composites. JSM Dent 1(2): 1013.

INTRODUCTION

Today, resin-based composites are widely used as restorative material. Most of the available composites contain a polymeric matrix of dimethacrylate monomers, inorganic filler particles coated with a methyl methacrylate-functional silane coupling agent to bond the filler to the organic matrix, and a photoinitiator system to permit photoactivation by light units [1,2] [1Bis-GMA is the monomer most used in dental composites, however due to its high molecular weight, high viscosity, and low mobility others monomers with lower viscosity and/or higher mobility, as TEGDMA and UDMA, are used to increase the degree of conversion (DC) and crosslinking of the polymer resultant [3]. During the polymerization reaction, resin-based composites are transformed from a viscous to a rigid state by a free radical polymerization of the dimethacrylate monomers present in their polymeric matrixes. This reaction involves the rupture of the C=C aliphatic bonds, the reduction of intermolecular distances of 0.3– 0.4 nm between polymer chains, maintained by Van der Waals attraction forces, and the establishment of primary C-C covalent bonds with lengths of about 0.15 nm [4,5].

Methacrylate restorative materials exhibit volumetric polymerization shrinkage5 and a significant proportion of unreacted monomer due the incomplete C=C bond conversion [6,7]. Thus, the study of others physical properties together with DC measurement are better to knowledge of the performance of dental materials [8,9]. However, there are many factors that affect the amount of light energy received at the top and bottom surfaces of a resin composite restoration, resulting in ineffective polymerization. These include: the design and size of the light guide; distance of the light guide tip from the dental composite; power density; exposure duration; shade [8] and opacity of the dental composite; increment thickness and material composition [10-12].

In the attempt to reduce these problems some techniques were proposed to decrease the shrinkage stress effects such as different incremental composite placement [13], light-curing protocols [14], and intermediate layer with hybrid glass ionomer and flowable composite [15] and materials with a low shrinkage monomer [16]. The silorene-based composites showed molecules presents a siloxane core with four oxirane rings attached that open upon polymerization to bond to other monomers [17]. The oxirane ring opening causes a volumetric expansion that partially compensates the shrinkage resultant from molecular bonding. Literature data confirmed that a silorane-based commercial composite presented less than 1.0% of total volumetric shrinkage, compared to 2.0–3.5% for Bis-GMA-based composites [17,18], causing less tooth deflection [13] and microleakage [19,20]. Its mechanical properties are comparable to those of dimethacrylate-based materials [21,22].

In deep cavities the reduction of the light intensity reaches the material due the distance between guide tip and resinous material surface is one factor that cannot be controlled by dentist during the restorative procedure. Thus, the restoration weakening can occur by lower DC and/or formation of more linear polymers, presenting inferior physical properties, such as reduced hardness, increased sorption, solubility [23], and discoloration [8]. The increase of the curing time and proximity of the tip of the device, increase the irradiance and consequently the energy density available for the monomer conversion can improve the physical properties of resin-based materials [7,24], and thus increase the long-term durability of adhesive restorations [25].

The DC is an important physical property that may have some impact on the restoration longevity, but this property alone is not enough to characterize the 3-dimensional dental composite structure, whereas different C=C bond concentrations coexist in the same polymer [26]. The same DC% value may result in different linear polymer content, which is more susceptible of softening than a more cross-linked polymer [6,27].

Miranda et al. [23] have investigated the sorption and solubility phenomena in nanofilled composites when immersed in mouthwashes contains alcohol, hydrogen peroxide and alcohol-free however due to changes in monomer composition becomes important to evaluate the effect of these solvents on matrices of microhybrid composites. The main purpose of this study was to evaluate the effect of light curing tip distance on the DC, sorption, and solubility of methacrylate and silorane-based composite resins after immersion in different solutions. The hypotheses tested were that: (1) there would be no difference between the materials and (2) the greatest distance from the tip distance of surface radiated decreases the physical properties tested. (3) There would a difference among solvents tested in the sorption and solubility.

METHODS AND MATERIALS

Two resins composites with different monomer compositions were analyzed: methacrylate-based composite (Filtek Z250, 3M ESPE, St Paul, MN, USA) and silorane-based composite (Filtek P90, 3M ESPE, St Paul, MN, USA). The composition of the composites is described in (Table 1).

Table 1: Type, manufacture and composition the composites analyzed in this study.

Composite

Manufacture

Composition*

 

 

Filtek Z250 shade A2

 

 

3M ESPE( St Paul, MN, USA)

Filler: 60 vol%, aluminum oxide, silica, and zirconium oxide (0.01-3.5 µm).

Resin: bisphenol-A glycidyl dimethacrylate (Bis-

GMA), ethoxylated bisphenol A dimetacrylate (Bis-EMA), and urethane dimethacrylate (UDMA).

 

 

Filtek P90 shade A2

 

 

3M ESPE( St Paul, MN, USA)

Filler: 55 vol%, silica, and yttrium trifluoride

(0.04-1.7 µm).

Resin: Bis-3,4-Epoxycyclohexylethyl- Phenyl-Methylsilane and

3,4-Epoxycyclohexylcyclopolymethylsiloxane.

*According to manufacturers.

Three mouth rinses were chosen: Plax Alcohol Free (Colgate-Palmolive), Plax Fresh Mint (ColgatePalmolive) and Plax Whitening (Colgate-Palmolive). Artificial saliva (Proderma) was used as the control. The composition and characteristics of the solutions are described in (Table 2).

Table 2: Solution, manufacture, pH and composition of the media immersions analyzed in this study.

Solution

Manufacture

pH

Composition*

Artificial

Saliva (AS)

Proderma

6,9

KCl, NaCl, MgCl, CaCl, nipacin, carboxymethyl, cellulose, sorbitol and deionized water

 

Plax Fresh Mint (PFM)

 

Colgate- Palmolive

 

 

6,6

Water, Sorbitol, Alcohol, Glycerin, Sodium, Lauryl Sulfate, Sodium Methyl Cocoyl Taurate, PVM/MA Copolymer, Aroma, Disodium Phosphate, Sodium Fluoride, Sodium Hydroxide, Triclosan, Sodium Saccharin, Cl 47005, Cl 42090

Plax Alcohol Free (PAF)

 

Colgate- Palmolive

 

4,9

Water, Glycerin, Propylene Glycol, Sorbitol, PEG- 40 Hydrogenated Castor Oil, Sodium Benzoate, Aroma, Phosforic Acid, Sodium Fluoride, Cetylpyridinium Chloride, Sodium Saccharin.

Plax Whitening (PW)

 

Colgate- Palmolive

 

3,8

Water, Sorbitol, Ethylic Alcohol (8%), Hydrogen peroxide 1,5%, Polaxamere 338, Polissorbate 20, Methyl salicilate, Menthol, Sodium saccharine,

Cl 42090

*According to manufacturers.

To measure the pH, 20 mL of each substance was added to a beaker, and the pH was obtained with a glass pH electrode 1.5 cm in diameter (PROCYON model AS 720 (Procyon Instrumental Científica) and each value is described in Table 2.

 

PREPARATION OF SPECIMENS

Cylindrical specimens were prepared in teflon ring molds (6.0 mm Ø and 1 mm height). A polyester strip was placed on a glass slab (Dentsply, Petropólis, RJ, Brazil) and teflon matrix. After filling the mold to excess, the material surface was covered with another polyester strip and a glass slide, and compressed with a device (500 g) for 20 s to accommodate the composite better and remove the excess material. All the composite specimens were light activated with an LED set (Flash Lite 1401, Discus Dental) for 20 s. Three curing tip distances were used in this study: 0 mm, 3 mm and 6 mm (Figure 1).

 Preparation of specimens.

Figure 1 Preparation of specimens.

The polymerization was performed with the light tip positioned in a device at a distance from the top surface of the sample that was controlled by an electronic digital caliper (Mitutoyo Sul Americana, Suzano, SP, Brazil). The optical power (mW) delivered by the device was measured with a power meter (Ophir Optronics, Har-Hotzvim, Jerusalem, Israel). The tip diameter was measured with digital caliper (Mitutoyo Sul Americana, Suzano, SP, Brazil) to determine tip area (cm2 ). Irradiance (mW/cm2 ) was calculated dividing optical power by tip area. The irradiance in each group were cured was determined by the ratio between power and area of the tip of the device, expressed in mW/cm2 (Figure 2).

 The irradiance for each distance of photoactivaton

Figure 2 The irradiance for each distance of photoactivaton

The measured values of irradiance and energy density are described in (Table 3).

Table 3: Power, irradiance and energy density of the LED Flash Lite 1401.

Tip of Distance

Power (mW)

Area (cm2)

Irradiance (mW/ cm2)

Energy Density (J)

0mm

310

0,5024

618

12,36

3mm

240

0,5024

478

9,56

6mm

160

0,5024

319

6,38

DEGREE OF CONVERSION

(DC%) After polymerization, the specimens were removed from the matrices, dry stored in light proof containers at 37º C for 24 h, and polished with 1200-grit silicon carbide (SiC) grinding paper (CarbiMet 2 Abrasive Discs, Buehler, Lake Bluff, IL, USA). The degree of conversion assessments was recorded in the absorbance mode using a Fourier transform infrared (FTIR) spectrometer model (Spectrum 100 FTIR/ UATR, Perkin Elmer) equipped with an attenuated total reflectance crystal (Figure 3a).

Figure 3 (a) - Spectra of the unpolymerized and polymerized specimens were  recorded with an FTIR spectrometer model Spectrum 100 FTIR/UATR / 3  (b) - The discs were placed in a desiccator containing freshly dried silica gel  and transferred to an oven at 37°C. After 24 hours, the discs were repeatedly  weighed on an analytical balance, until a constant mass (m1) was attained.  After final drying, the thickness and diameter of the discs were measured at  four points with a digital and the volume (V) was calculated in mm3. The discs  were then individually placed in plastic vials and immersed in 1 ml of artificial  saliva at 37°C. Twice a day, the discs were immersed in 2 ml of each mouthwash  for two minutes (12 hour intervals) and agitation in orbital rotational table  and immersion in the respective mouthwashes, the discs were immersed in  artificial saliva. After thirty days, the discs were removed from the vials, washed  in distilled water and weighed (m2). The discs were then placed in a desiccator  and weighed daily until the mass variation was less than 0.1 mg (m3).

Figure 3 (a) - Spectra of the unpolymerized and polymerized specimens were recorded with an FTIR spectrometer model Spectrum 100 FTIR/UATR / 3 (b) - The discs were placed in a desiccator containing freshly dried silica gel and transferred to an oven at 37°C. After 24 hours, the discs were repeatedly weighed on an analytical balance, until a constant mass (m1) was attained. After final drying, the thickness and diameter of the discs were measured at four points with a digital and the volume (V) was calculated in mm3. The discs were then individually placed in plastic vials and immersed in 1 ml of artificial saliva at 37°C. Twice a day, the discs were immersed in 2 ml of each mouthwash for two minutes (12 hour intervals) and agitation in orbital rotational table and immersion in the respective mouthwashes, the discs were immersed in artificial saliva. After thirty days, the discs were removed from the vials, washed in distilled water and weighed (m2). The discs were then placed in a desiccator and weighed daily until the mass variation was less than 0.1 mg (m3).

Standard increments of each resin composite were compressed between two polyethylene strips and two glass slides to produce a thin film. Five specimens were prepared for each distance. Absorption spectra of the cured and uncured composites were obtained in the top and bottom surfaces with 16 scans at 4 cm-1 resolution in the region between 1000-2000 and 600-2000 cm-1 for methacrylate and silorane-based resins, respectively. To calculate the DC the ratio (R) between the peak heights of the C=C aliphatic (1638 cm-1) and aromatic (1608 cm-1) for methacrylate, and oxirane (C-O-C) - 770 cm-1- and siloxane (C-H) - 1038 cm-1- for silorane band absorptions for cured and uncured composite was used. The formula: DC (%) = [1 – (R polymer/R monomer)] x 100 was used to calculate the DC.

SORPTION (SP) AND SOLUBILITY (SL)

The specimens were stored in desiccator at 37 ºC containing silica gel and daily weighted in an analytical balance (Tel Marke, Bel Quimis, São Paulo, SP, Brazil) accurate to 0.001 mg, constituting a weighing cycle every 24 h. The complete cycle was repeated until a constant mass (m1) was obtained until that the mass loss of each specimen was not more than 0.1 mg per 24 h cycle. Thickness (4 measurements at four equally points on the circumference) and diameter (2 measurements at the right angles) of each specimen were measured using a digital electronic caliper. Mean values were used to calculate the volume (v) of each specimen (mm3 ). The discs were then individually placed in plastic vials and immersed in 1 ml of artificial saliva at 37°C. Twice a day, the discs were immersed in 2 ml of each mouthrinse for two minutes (12 hr intervals) and agitation in orbital rotational table (MA 140 CFT, Marconi, Piracicaba). After immersion in the respective mouthrinses, the discs were immersed in artificial saliva. A control group was kept in artificial saliva at 37°C throughout the entire experiment. After 30 days, the discs were removed from the vials, washed in distilled water and weighed (m2). The discs were then placed in a desiccator and weighed daily until the mass variation was less than ± 0.1 mg (m3) (Figure 3b). The sorption (Sp) and solubility (Sl) were obtained using the following formulas:

Sl = m1 -m3 /V Sp = m2 -m3 /V

where m1 is the conditioned mass prior to immersion in the solvent in μg; m2 is the mass of the specimen after immersion in the solvent in μg; m3 is the reconditioned mass in μg; V is the volume of the specimen in mm3 . The units used in the formula were (μg/mm3 ).

After exploratory data analysis was applied to analysis of variance (ANOVA) in a split plot design to degree of conversion and in factorial for sorption, multiple comparisons were performed by Tukey’s test. The solubility data did not meet the assumptions of ANOVA and were analyzed by the non-parametric Kruskal Wallis and Dunn’s test. In all analyzes was considered the significance level of 5%.

RESULTS

Degree of Conversion (DC%)

(Table 4) shows the means and standard deviations of DC%.

Tabela 4: Means and standard deviations of the degree of conversion in top and bottom surfaces.

Surface

Distance (mm)

Composite

 

 

Z250

P90

Bottom

0

58.88 (2.19) Aa

49,68 (2,61) Ba

 

3

58.92 (3.08) Aa

49.83 (3.74) Ba

 

6

55.70 (3.90) Ab

46.62 (3.00) Bb

Top

0

58.35 (1.64) Aa

51.11 (2.78) Ba

 

3

58.93 (0.88) Aa

50.65 (4.78) Ba

 

6

54.21 (1.42) Ab

47.96 (1.85) Bb

Means followed by distinct capital letters in the same row and distinct small letters

in the same column are significantly different at P < 0.05.

The ANOVA in the split plot showed an interaction between the surfaces and light curing tip distances (P = 0.03). The results showed that, regardless of the surface and the distance light activation, methacrylate showed significant higher DC than silorane-based composite. Furthermore, for two types of composites tested, there was only a difference in DC (top and bottom) when the samples were photoactivated for distance of 6mm. There was no statistical difference in DC between top and bottom surfaces.

Sorption

(Table 5) shows the means and standard deviations of sorption.

Table 5: Means and standard deviations of solvent sorption in μg/mm3.

 

Composite

Solution

Distance (mm)

 

 

0

3

6

P90

AS

*9,60 (1,59) Aa

*10.23 (3.63) Aa

*10.83 (2.61) Aa

 

PFM

*10.41 (1.54) Aa

*11.72 (3.02) Ab

*12.79 (1.32) Bb

 

PAF

*10.33 (1.23) Aa

*10.71 (3.16) Aa

*12.16 (2.56) Ab

 

PW

*13.97 (1.91) Ab

*14.05 (1.79) Bb

*16.46 (3.85) Cc

Z250

AS

20.24 (0.67) Aa

20.56 (1.36) Aa

20.53 (1.44) Aa

 

PFM

21.56 (1.29) Aa

21.89 (1.30) Aa

23.53 (1.21) Bb

 

PAF

20.72 (0.64) Aa

20.90 (1.38) Aa

23.44 (1.35) Bb

 

PW

22.43 (1.38) Aa

23.85 (0.64) Bb

27.71 (1.34) Cc

Means followed by distinct capital letters in the same row and distinct small letters in the same column are significantly different at P < 0.05. * Differs the resin Z250 in the same solution and distance (p ≤ 0.05).

For the sorption was found statistical difference between the variables: resin, distance of photoactivation and mouthrinses (p<0,05). The data showed that, regardless of the distance photoactivation and the immersion medium, the rate of sorption-based composite silorane (P90) was significantly lower than the methacrylate-based composite (Z250). Moreover, the artificial saliva did not affect the increase in rate of sorption in any of the photoactivation distances. In 3mm and 6mm light distance, the mouthwash Plax Whitening caused the increase of sorption for the two composites. For the composite Z250, the Plax Fresh Mint demonstrated the influence of sorption values only when the polymerization was carried out to 6mm; differently for composite P90, the same mouthwash already changed the rate of sorption when the polymerization was carried out to 3mm. When photoactivated to 6mm, all mouthwashes tested caused a significant increase in the rate of sorption both in the artificial saliva.

Solubility

The data of (Table 6) showed median and maximum and minimum values of each solvent solubility.

Table 6: Median and maximum and minimum values of solvent solubility in μg/mm3.

Composite

Solution

Distance

 

 

0 mm

3 mm

6 mm

P90

AS

-4,73 (-7,95; -2,28) Aa

-5.32 (-9.90; -2.52) Aa

-4.49 (-7.90; -2.12) Ab

 

PFM

-5.41 (-9.55; -2.60) Aa

-5.53 (-11.55; -2.42) Aa

-4.86 (-7.70; -2.53) Ab

 

PAF

-5.03 (-7.88; -2.38) Aa

-2.63 (-10.05; 0.00) Aa

-2.64 (-4.98; 0.00) Aab

 

PW

-2.30 (-2.72; 0.00) Aa

-6.09 (-8.98; -4.04) Ba

-2.40 (-2,46; 0.00;) Aa

Z250

AS

-5.52 (-8.16; -2.79) Aa

-5.47 (-9.03; 0.00 ) Aab

-5.23 (-9.22; -2.77) Aa

 

PFM

-6.24 (-9.87; -2.59) Aa

-7.69 (-9.36; -5.57) Aab

-7.25 (-14.12; -2.79)Aa

 

PAF

-5.13 (-8.39; 0.00) Aa

-2.96 (-6.35; -2.40) Aa

-2.49 (-11.57; 2.77) Aa

 

PW

-2.78 (-8.72; 0.00) Aa

-9.25 (-14.78; -5.61) Ab

-4.60 (-12.09; -2.67)Aa

Means followed by distinct capital letters in the same row and distinct small letters in the same column are significantly different at P < 0.05.

Although it is noticed statistical differences among the factors, negative values attributed indicate an inconclusive result.

DISCUSSION

The clinical performance of dental composites is to a great extent dependent on their mechanical properties and resistance to chemical degradation by acids and other organic substances found in the oral cavity [28,29]. A satisfactory degree of conversion of the composite may be associated with the polymer network, with different amounts of cross linking [30], which can be influenced by the distance between the tip end of the curing light and the composite surface [8,23].

The distance between the light source tip end and composite surface is another important factor to be considered. Clinical variations have showed that this distance directly affects light intensity that reaches the material [23,31] and thus interferes in the polymerization depth and degree of conversion[23]. Unlike previous studies [23], this study did not observe a statistical difference between the top surface and base for any of the composites tested. Furthermore, it can be noted that regardless of the composite when the polymerization was performed at 6 mm, the DC was significantly lower (top and bottom). Although studies demonstrate that polymerization is a phenomenon not uniform [23,32], it is believed that the results obtained in this study are justified by the thickness of the specimen made (1mm). The literature has shown that larger increments than 2mm could favor differences in DC’s top and bottom restoration.

Studies [23]. have shown that photoactivation at 6 mm from the tip end of the light curing unit to the composite surface led to a decrease of 50% in the amount of irradiance reaching the material’s surface. Coincidentally, for the 6 mm distance, the irradiance observed was 319 mW/cm2 , which corresponds to about half of the irradiance for the 0 mm distance, which was 618 mW/cm2 . This light dispersion yielded to a loss of energy dose and probably promoted a lower camphorquinone excitation [32,33] and a polymer chain formation with lower crosslinks [30]. Thus, there will be more space for solvent molecules to diffuse inside the polymer network, making the polymer more susceptible to the plasticization effect of solvent [34].

Thus, the first hypothesis that both materials showed similar performance was rejected. According to results of this current investigation, higher DC was found for methacrylate compared to silorane composite [26]. Probably, the UDMA monomer contained in the Filtek Z250 composite gives more mobility and has been related to increase DC3 ; and differences in the mechanism of the polymerization reaction can explain these results. Methacrylate is cured by radical intermediates and cycloaliphatic oxirane polymerizes via cationic intermediates [6]. Moreover, the onset of cationic ring-opening polymerization of the silorane is slower due to the necessary formation of sufficient cations to initiate the polymerization, thus more time of light-curing is required compared to radical cure of methacrylate monomers molecules into polymer network [5,13].

Another plausible explanation for the lower degree of conversion of the silorane-based composite that would the light-curing time recommended for silorane composite resin using quartz-tungsten-halogen (QTH) with irradiance between 500-1400 mW/cm2 is 40 s, as well as LEDs with output between 500-1000 mW/cm2 . For LEDs with irradiance between 1000- 1500 mW/cm2 is indicated an exposure light time of 20 s. In this study, to maintain a standardized with the methacrylate-based composite was standardized time of 20 seconds using a second generation LED for each distance photoactivation tested. It may have happened due to the short time of light curing for all specimens (20 s), which possibly resulted in a low energy dose and contributing to form a less established polymer network [32,35]

The data showed that, regardless of the distance photoactivation and the immersion medium, the rate of sorptionbased composite silorane (P90) was significantly lower than the methacrylate-based composite (Z250) . This can be explained by the composition of the material and not by the DC. Moreover, this result showed that the polymeric structure formation of the silorane based composite may be different of the methacrylate one and it should be more elucidated in future studies. The monomers present in the polymeric matrices of the methacrylate-based composite (Filtek Z250) (Bis-GMA, Bis-EMA, TEGDMA, UDMA) have hydrophilic groups in their backbones, i.e., -OH-, >C=O, -O-, -NH-[36,37], which probably make them more prone to salivary sorption. In addition to the polymeric matrix, the filler particle system may also influence the sorption phenomenon in resin composites [2]. Besides that, silorane represents a merger of siloxane and oxirane species and reveals good biocompatibility even in uncured condition and high hydrophobicity and oxirane exhibits low shrinkage and high reactivity [22,38]. Thus, this more hydrophobic nature of the silorane may contribute for lower sorption comparable to conventional methacrylate resin-based.

Regardless of the type of composite, saliva did not influence the rate of sorption in no distance photoactivation. Thus, it is believed that, even with the possibility of different configurations crosslinking, the difference of the observed sorption 3 mm to 6 mm and PW is justified by its composition and pH. That is, the presence of hydrogen peroxide at low concentration (1.5%) decrease in pH favors the challenge solution (3,8%). , Regarding the effects of hydrogen peroxide in the composite matrix, it is known that acid solutions can change the composition of organic resinous material [39], due to the high oxidative power of hydrogen peroxide. Miranda et al. [23] showed that even in low concentrations, it is capable of causing harm to the links polymer, yielding this material to be more susceptible to softening and degradation.

Another important observation is that the 6mm, the UFW had similar behavior to PAF. Notably, (Table 2) shows that the pH of PAF is less than the PFM. Miranda et al. [23] verified the presence in Plax Alcohol Free of phosphoric acid (0.174 g / l), which, even in small quantities, could reduce the pH of the solution and change the sorption phenomena and hygroscopic expansion, due to the presence of free hydrogen groups [40].

Almeida et al. [28] showed that low pH mouthrinses may have a role in the polymer composite resin through the catalysis of ester groups from dimethacrylate monomers present in their compositions (Bis-GMA, Bis- Ema, UDMA and TEGDMA) .The hydrolysis of these ester groups can form alcohol and carboxylic acid molecules, which can accelerate the degradation of the composite resin, due to the low pH inside their matrixes [28]. On the other hand, the low pH cause softening of the matrix surface by removing the monomer structure of the polymer [30], or can promote an opening in the structure of the polymer, facilitating saliva diffusion [28] and decreasing its physical properties [41,42] , accelerating the detachment or release of ions from its surface [34,43] .

The susceptibility of the more linear or less crosslink polymer to softening [26] in solvents may be explained by the solvent-polymer interaction and, consequently, by Hoy’s solubility parameter for polar forces [44]. The solubility of the composite is strongly influenced by monomer conversion [45], and high hydrophobicity of the siloxane species may decrease the solubility of the silorane [26]. However, although it can be observed statistical differences in solubility values, negative values observed for all factors examined (composite, distance and solution) lead to a more rational conclusion that the phenomenon occurred; the composites tested were more susceptible to water sorption leading to mass gain [44], which could mask the real solubility [46]. It does not mean that no solubility occurred, but rather that the water sorption was greater than the solubility [47], because the final mass was greater than the original. Supposedly, some molecules of the solvent, the polymer chains are joined by hydrogen bonds, as occurs with water, and remained firmly adhered to the polar sites along the polymer network [46] preventing the removal of all the solvent during the dissection [48].

Although this study attempted to simulate cycles alternating between saliva and mouthwash, the chemical degradation of the restoration surface in vivo is the result of complex reactions with different chemicals components. Clinically, the mouthwashes’ effects on composite resins may be different according to some factors, such as acquired film, food inhabits, beverages, and oral care products, which cannot be reproduced in vitro. Those factors, acting together or in isolation, may interfere with the physical and mechanical properties of the materials, influencing the durability of the restorative treatment [23,29].

CONCLUSIONS

Under the conditions of this in vitro study, it may be concluded that: (1) the composite metacrylate-based showed higher DC compared to the silorano-based composite; no statistical difference in DC from top and bottom. Only when the polymerization was carried out to 6mm, the DC was significantly lower for both composites. (2) the methacrylate-based composite had higher rates of sorption than the base composite silorano; saliva did not affect sorption, regardless of the distance and of the composite. The PW showed significantly change the sorption, regardless of the type of composite; (3) the solubility test demonstrated negative data, masking the real solubility

REFERENCES

1. Sideridou I, Tserki V, Papanastasiou G. Effect of chemical structure on degree of conversion in light-cured dimethacrylate-based dental resins. Biomaterials. 2002; 23: 1819-1829.

2. Gonçalves L, Filho JD, Guimarães JG, Poskus LT, Silva EM. Solubility, salivary sorption and degree of conversion of dimethacrylate-based polymeric matrixes. J Biomed Mater Res B Appl Biomater. 2008; 85: 320-325.

3. Filho JD, Poskus LT, Guimarães JG, Barcellos AA, Silva EM. Degree of conversion and plasticization of dimethacrylate-based polymeric matrices: influence of light-curing mode. J Oral Sci. 2008; 50: 315-321.

4. Ferracane JL, Greener EH. The effect of resin formulation on the degree of conversion and mechanical properties of dental restorative resins. J Biomed Mater Res. 1986; 20: 121-131.

5. Van Ende A, De Munck J, Mine A, Lambrechts P, Van Meerbeek B. Does a low-shrinking composite induce less stress at the adhesive interface? Dent Mater. 2010; 26: 215-222.

6. Weinmann W, Thalacker C, Guggenberger R. Siloranes in dental composites. Dent Mater. 2005; 21: 68-74.

7. Yap AU, Seneviratne C. Influence of light energy density on effectiveness of composite cure. Oper Dent. 2001; 26: 460-466. 

8. Aguiar FH, Lazzari CR, Lima DA, Ambrosano GM, Lovadino JR. Effect of light curing tip distance and resin shade on microhardness of a hybrid resin composite. Braz Oral Res. 2005; 19: 302-306

9. Yoon TH, Lee YK, Lim BS, Kim CW. Degree of polymerization of resin composites by different light sources. J Oral Rehabil. 2002; 29: 1165- 1173.

10. Caldas DB, de Almeida JB, Correr-Sobrinho L, Sinhoreti MA, Consani S. Influence of curing tip distance on resin composite Knoop hardness number, using three different light curing units. Oper Dent. 2003; 28: 315-320.

11. Price RB, Dérand T, Loney RW, Andreou P. Effect of light source and specimen thickness on the surface hardness of resin composite. Am J Dent. 2002; 15: 47-53.

12. Soh MS, Yap AU, Siow KS. Effectiveness of composite cure associated with different curing modes of LED lights. Oper Dent. 2003; 28: 371- 377.

13. Palin WM, Fleming GJ, Nathwani H, Burke FJ, Randall RC. In vitro cuspal deflection and microleakage of maxillary premolars restored with novel low-shrink dental composites. Dent Mater. 2005; 21: 324- 335.

14. Aguiar FH, Ajudarte KF, Lovadino JR. Effect of light curing modes and filling techniques on microleakage of posterior resin composite restorations. Oper Dent. 2002; 27: 557-562.

15. Xie H, Zhang F, Wu Y, Chen C, Liu W. Dentine bond strength and microleakage of flowable composite, compomer and glass ionomer cement. Aust Dent J. 2008; 53: 325-331.

16. Boaro LC, Gonçalves F, Guimarães TC, Ferracane JL, Versluis A, Braga RR. Polymerization stress, shrinkage and elastic modulus of current low-shrinkage restorative composites. Dent Mater. 2010; 26: 1144- 1150.

17. Weinmann W, Thalacker C, Guggenberger R. Siloranes in dental composites. Dent Mater. 2005; 21: 68-74.

18. Bouillaguet S, Gamba J, Forchelet J, Krejci I, Wataha JC. Dynamics of composite polymerization mediates the development of cuspal strain. Dent Mater. 2006; 22: 896-902.

19. Bagis YH, Baltacioglu IH, Kahyaogullari S. Comparing microleakage and the layering methods of silorane-based resin composite in wide Class II MOD cavities. Oper Dent. 2009; 34: 578-585.

20. Yamazaki PC, Bedran-Russo AK, Pereira PN, Wsift EJ Jr. Microleakage evaluation of a new low-shrinkage composite restorative material. Oper Dent. 2006; 31: 670-676.

21. Ilie N, Hickel R. Macro-, micro- and nano-mechanical investigations on silorane and methacrylate-based composites. Dent Mater. 2009; 25: 810-819.

22. Duarte S Jr, Botta AC, Phark JH, Sadan A. Selected mechanical and physical properties and clinical application of a new low-shrinkage composite restoration. Quintessence Int. 2009; 40: 631-638.

23. de Azevedo Miranda D, dos Santos Bertoldo CE, Ambrosano GM, Aguiar FH, Lima DA, Lovadino JR. Effect of curing light distance and different mouthwashes on the sorption and solubility of a nanofilled composite. Eur J Esthet Dent. 2013; 8: 88-102.

24. Aguiar FH, Braceiro A, Lima DA, Ambrosano GM, Lovadino JR. Effect of light curing modes and light curing time on the microhardness of a hybrid composite resin. J Contemp Dent Pract. 2007; 8: 1-8.

25. Da Rosa Rodolpho PA, Donassollo TA, Cenci MS, Loguércio AD, Moraes RR, Bronkhorst EM, et al. 22-Year clinical evaluation of the performance of two posterior composites with different filler characteristics. Dent Mater. 2011; 27: 955-963.

26. Kusgoz A, Ülker M, Yesilyurt C, Yoldas OH, Ozil M, Tanriver M. Silorane-based composite: depth of cure, surface hardness, degree of conversion, and cervical microleakage in Class II cavities. J Esthet Restor Dent. 2011; 23: 324-335.

27. Schneider LF, Moraes RR, Cavalcante LM, Sinhoreti MA, CorrerSobrinho L, Consani S. Cross-link density evaluation through softening tests: effect of ethanol concentration. Dent Mater. 2008; 24: 199-203.

28. Almeida GS, Poskus LT, Guimarães JG, da Silva EM. The effect of mouthrinses on salivary sorption, solubility and surface degradation of a nanofilled and a hybrid resin composite. Oper Dent. 2010; 35: 105-111.

29. Miranda Dde A, Bertoldo CE, Aguiar FH, Lima DA, Lovadino JR. Effects of mouthwashes on Knoop hardness and surface roughness of dental composites after different immersion times. Braz Oral Res. 2011; 25: 168-173.

30. Asmussen E, Peutzfeldt A. Influence of selected components on crosslink density in polymer structures. Eur J Oral Sci. 2001; 109: 282- 285.

31. Aguirar FH, e Oliveria TR, Lima DA, Ambrosano Gm, Lovadino JR. Microhardness of different thicknesses of resin composite polymerized by conventional photocuring at different distances. Gen Dent. 2008; 56: 144-148.

32. de Araújo CS, Schein MT, Zanchi CH, Rodrigues SA Jr, Demarco FF. Composite resin microhardness: the influence of light curing method, composite shade, and depth of cure. J Contemp Dent Pract. 2008; 9: 43-50.

33. Soh MS, Yap AU. Influence of curing modes on crosslink density in polymer structures. J Dent. 2004; 32: 321-326.

34. erracane JL. Hygroscopic and hydrolytic effects in dental polymer networks. Dent Mater. 2006; 22: 211-222.

35. Lindberg A, Peutzfeldt A, van Dijken JW. Effect of power density of curing unit, exposure duration, and light guide distance on composite depth of cure. Clin Oral Investig. 2005; 9: 71-76.

36. Sabbagh J, Ryelandt L, Bachérius L, Biebuyck JJ, Vreven J, Lambrechts P, et al. Characterization of the inorganic fraction of resin composites. J Oral Rehabil. 2004; 31: 1090-1101.

37. Santerre JP, Shajii L, Leung BW. Relation of dental composite formulations to their degradation and the release of hydrolyzed polymeric-resin-derived products. Crit Rev Oral Biol Med. 2001; 12: 136-151.

38. Guggenberger R, Weinmann W. Exploring beyond methacrylates. Am J Dent. 2000; 13: 82D-84D.

39. de Alexandre RS, Sundfeld RH, Briso AL, Bedran-Russo AK, Valentino TA, Sundefeld ML. Effect of 10% carbamide peroxide dental bleaching on microhardness of filled and unfilled sealant materials. J Esthet Restor Dent. 2006; 18: 273-278.

40. Ortengren U, Andersson F, Elgh U, Terselius B, Karlsson S. Influence of pH and storage time on the sorption and solubility behaviour of three composite resin materials. J Dent. 2001; 29: 35-41.

41. Benetti AR, Asmussen E, Munksgaard EC, Dewaele M, Peutzfeldt A, Leloup G, et al. Softening and elution of monomers in ethanol. Dent Mater. 2009; 25: 1007-1013.

42. Aguiar FH, Braceiro AT, Ambrosano GM, Lovadino JR. Hardness and diametral tensile strength of a hybrid composite resin polymerized with different modes and immersed in ethanol or distilled water media. Dent Mater. 2005; 21: 1098-1103.

43. Gonçalves F, Kawano Y, Braga RR. Contraction stress related to composite inorganic content. Dent Mater. 2010; 26: 704-709.

44. Lopes LG, Jardim Filho Ada V, de Souza JB, Rabelo D, Franco EB, de Freitas GC. Influence of pulse-delay curing on sorption and solubility of a composite resin. J Appl Oral Sci. 2009; 17: 27-31.

45. da Silva EM, Almeida GS, Poskus LT, Guimarães JG. Relationship between the degree of conversion, solubility and salivary sorption of a hybrid and a nanofilled resin composite. J Appl Oral Sci. 2008; 16: 161-166.

46. Malacarne J, Carvalho RM, de Goes MF, Svizero N, Pashley DH, Tay FR, et al. Water sorption/solubility of dental adhesive resins. Dent Mater. 2006; 22: 973-980

47. Fabre HS, Fabre S, Cefaly DF, de Oliveira Carrilho MR, Garcia FC, Wang L. Water sorption and solubility of dentin bonding agents light-cured with different light sources. J Dent. 2007; 35: 253-258.

48. Janda R, Roulet JF, Latta M, Rüttermann S. Water sorption and solubility of contemporary resin-based filling materials. J Biomed Mater Res B Appl Biomater. 2007; 82: 545-551

de Azevedo Miranda D, Pini NP, Bovi Ambrosano GM, Baggio Aguiar FH, Leite Lima DAN, et al. (2013) Effect of Light Curing Tip Distance and Immersion Media on the Degree of Conversion, Sorption and Solubility of Methacylate and Silorane-Based Composites. JSM Dent 1(2): 1013

Received : 25 Jun 2013
Accepted : 07 Aug 2013
Published : 09 Aug 2013
Journals
Annals of Otolaryngology and Rhinology
ISSN : 2379-948X
Launched : 2014
JSM Schizophrenia
Launched : 2016
Journal of Nausea
Launched : 2020
JSM Internal Medicine
Launched : 2016
JSM Hepatitis
Launched : 2016
JSM Oro Facial Surgeries
ISSN : 2578-3211
Launched : 2016
Journal of Human Nutrition and Food Science
ISSN : 2333-6706
Launched : 2013
JSM Regenerative Medicine and Bioengineering
ISSN : 2379-0490
Launched : 2013
JSM Spine
ISSN : 2578-3181
Launched : 2016
Archives of Palliative Care
ISSN : 2573-1165
Launched : 2016
JSM Nutritional Disorders
ISSN : 2578-3203
Launched : 2017
Annals of Neurodegenerative Disorders
ISSN : 2476-2032
Launched : 2016
Journal of Fever
ISSN : 2641-7782
Launched : 2017
JSM Bone Marrow Research
ISSN : 2578-3351
Launched : 2016
JSM Mathematics and Statistics
ISSN : 2578-3173
Launched : 2014
Journal of Autoimmunity and Research
ISSN : 2573-1173
Launched : 2014
JSM Arthritis
ISSN : 2475-9155
Launched : 2016
JSM Head and Neck Cancer-Cases and Reviews
ISSN : 2573-1610
Launched : 2016
JSM General Surgery Cases and Images
ISSN : 2573-1564
Launched : 2016
JSM Anatomy and Physiology
ISSN : 2573-1262
Launched : 2016
JSM Dental Surgery
ISSN : 2573-1548
Launched : 2016
Annals of Emergency Surgery
ISSN : 2573-1017
Launched : 2016
Annals of Mens Health and Wellness
ISSN : 2641-7707
Launched : 2017
Journal of Preventive Medicine and Health Care
ISSN : 2576-0084
Launched : 2018
Journal of Chronic Diseases and Management
ISSN : 2573-1300
Launched : 2016
Annals of Vaccines and Immunization
ISSN : 2378-9379
Launched : 2014
JSM Heart Surgery Cases and Images
ISSN : 2578-3157
Launched : 2016
Annals of Reproductive Medicine and Treatment
ISSN : 2573-1092
Launched : 2016
JSM Brain Science
ISSN : 2573-1289
Launched : 2016
JSM Biomarkers
ISSN : 2578-3815
Launched : 2014
JSM Biology
ISSN : 2475-9392
Launched : 2016
Archives of Stem Cell and Research
ISSN : 2578-3580
Launched : 2014
Annals of Clinical and Medical Microbiology
ISSN : 2578-3629
Launched : 2014
JSM Pediatric Surgery
ISSN : 2578-3149
Launched : 2017
Journal of Memory Disorder and Rehabilitation
ISSN : 2578-319X
Launched : 2016
JSM Tropical Medicine and Research
ISSN : 2578-3165
Launched : 2016
JSM Head and Face Medicine
ISSN : 2578-3793
Launched : 2016
JSM Cardiothoracic Surgery
ISSN : 2573-1297
Launched : 2016
JSM Bone and Joint Diseases
ISSN : 2578-3351
Launched : 2017
JSM Bioavailability and Bioequivalence
ISSN : 2641-7812
Launched : 2017
JSM Atherosclerosis
ISSN : 2573-1270
Launched : 2016
Journal of Genitourinary Disorders
ISSN : 2641-7790
Launched : 2017
Journal of Fractures and Sprains
ISSN : 2578-3831
Launched : 2016
Journal of Autism and Epilepsy
ISSN : 2641-7774
Launched : 2016
Annals of Marine Biology and Research
ISSN : 2573-105X
Launched : 2014
JSM Health Education & Primary Health Care
ISSN : 2578-3777
Launched : 2016
JSM Communication Disorders
ISSN : 2578-3807
Launched : 2016
Annals of Musculoskeletal Disorders
ISSN : 2578-3599
Launched : 2016
Annals of Virology and Research
ISSN : 2573-1122
Launched : 2014
JSM Renal Medicine
ISSN : 2573-1637
Launched : 2016
Journal of Muscle Health
ISSN : 2578-3823
Launched : 2016
JSM Genetics and Genomics
ISSN : 2334-1823
Launched : 2013
JSM Anxiety and Depression
ISSN : 2475-9139
Launched : 2016
Clinical Journal of Heart Diseases
ISSN : 2641-7766
Launched : 2016
Annals of Medicinal Chemistry and Research
ISSN : 2378-9336
Launched : 2014
JSM Pain and Management
ISSN : 2578-3378
Launched : 2016
JSM Women's Health
ISSN : 2578-3696
Launched : 2016
Clinical Research in HIV or AIDS
ISSN : 2374-0094
Launched : 2013
Journal of Endocrinology, Diabetes and Obesity
ISSN : 2333-6692
Launched : 2013
Journal of Substance Abuse and Alcoholism
ISSN : 2373-9363
Launched : 2013
JSM Neurosurgery and Spine
ISSN : 2373-9479
Launched : 2013
Journal of Liver and Clinical Research
ISSN : 2379-0830
Launched : 2014
Journal of Drug Design and Research
ISSN : 2379-089X
Launched : 2014
JSM Clinical Oncology and Research
ISSN : 2373-938X
Launched : 2013
JSM Bioinformatics, Genomics and Proteomics
ISSN : 2576-1102
Launched : 2014
JSM Chemistry
ISSN : 2334-1831
Launched : 2013
Journal of Trauma and Care
ISSN : 2573-1246
Launched : 2014
JSM Surgical Oncology and Research
ISSN : 2578-3688
Launched : 2016
Annals of Food Processing and Preservation
ISSN : 2573-1033
Launched : 2016
Journal of Radiology and Radiation Therapy
ISSN : 2333-7095
Launched : 2013
JSM Physical Medicine and Rehabilitation
ISSN : 2578-3572
Launched : 2016
Annals of Clinical Pathology
ISSN : 2373-9282
Launched : 2013
Annals of Cardiovascular Diseases
ISSN : 2641-7731
Launched : 2016
Journal of Behavior
ISSN : 2576-0076
Launched : 2016
Annals of Clinical and Experimental Metabolism
ISSN : 2572-2492
Launched : 2016
Clinical Research in Infectious Diseases
ISSN : 2379-0636
Launched : 2013
JSM Microbiology
ISSN : 2333-6455
Launched : 2013
Journal of Urology and Research
ISSN : 2379-951X
Launched : 2014
Journal of Family Medicine and Community Health
ISSN : 2379-0547
Launched : 2013
Annals of Pregnancy and Care
ISSN : 2578-336X
Launched : 2017
JSM Cell and Developmental Biology
ISSN : 2379-061X
Launched : 2013
Annals of Aquaculture and Research
ISSN : 2379-0881
Launched : 2014
Clinical Research in Pulmonology
ISSN : 2333-6625
Launched : 2013
Journal of Immunology and Clinical Research
ISSN : 2333-6714
Launched : 2013
Annals of Forensic Research and Analysis
ISSN : 2378-9476
Launched : 2014
JSM Biochemistry and Molecular Biology
ISSN : 2333-7109
Launched : 2013
Annals of Breast Cancer Research
ISSN : 2641-7685
Launched : 2016
Annals of Gerontology and Geriatric Research
ISSN : 2378-9409
Launched : 2014
Journal of Sleep Medicine and Disorders
ISSN : 2379-0822
Launched : 2014
JSM Burns and Trauma
ISSN : 2475-9406
Launched : 2016
Chemical Engineering and Process Techniques
ISSN : 2333-6633
Launched : 2013
Annals of Clinical Cytology and Pathology
ISSN : 2475-9430
Launched : 2014
JSM Allergy and Asthma
ISSN : 2573-1254
Launched : 2016
Journal of Neurological Disorders and Stroke
ISSN : 2334-2307
Launched : 2013
Annals of Sports Medicine and Research
ISSN : 2379-0571
Launched : 2014
JSM Sexual Medicine
ISSN : 2578-3718
Launched : 2016
Annals of Vascular Medicine and Research
ISSN : 2378-9344
Launched : 2014
JSM Biotechnology and Biomedical Engineering
ISSN : 2333-7117
Launched : 2013
Journal of Hematology and Transfusion
ISSN : 2333-6684
Launched : 2013
JSM Environmental Science and Ecology
ISSN : 2333-7141
Launched : 2013
Journal of Cardiology and Clinical Research
ISSN : 2333-6676
Launched : 2013
JSM Nanotechnology and Nanomedicine
ISSN : 2334-1815
Launched : 2013
Journal of Ear, Nose and Throat Disorders
ISSN : 2475-9473
Launched : 2016
JSM Ophthalmology
ISSN : 2333-6447
Launched : 2013
Journal of Pharmacology and Clinical Toxicology
ISSN : 2333-7079
Launched : 2013
Annals of Psychiatry and Mental Health
ISSN : 2374-0124
Launched : 2013
Medical Journal of Obstetrics and Gynecology
ISSN : 2333-6439
Launched : 2013
Annals of Pediatrics and Child Health
ISSN : 2373-9312
Launched : 2013
JSM Clinical Pharmaceutics
ISSN : 2379-9498
Launched : 2014
JSM Foot and Ankle
ISSN : 2475-9112
Launched : 2016
JSM Alzheimer's Disease and Related Dementia
ISSN : 2378-9565
Launched : 2014
Journal of Addiction Medicine and Therapy
ISSN : 2333-665X
Launched : 2013
Journal of Veterinary Medicine and Research
ISSN : 2378-931X
Launched : 2013
Annals of Public Health and Research
ISSN : 2378-9328
Launched : 2014
Annals of Orthopedics and Rheumatology
ISSN : 2373-9290
Launched : 2013
Journal of Clinical Nephrology and Research
ISSN : 2379-0652
Launched : 2014
Annals of Community Medicine and Practice
ISSN : 2475-9465
Launched : 2014
Annals of Biometrics and Biostatistics
ISSN : 2374-0116
Launched : 2013
JSM Clinical Case Reports
ISSN : 2373-9819
Launched : 2013
Journal of Cancer Biology and Research
ISSN : 2373-9436
Launched : 2013
Journal of Surgery and Transplantation Science
ISSN : 2379-0911
Launched : 2013
Journal of Dermatology and Clinical Research
ISSN : 2373-9371
Launched : 2013
JSM Gastroenterology and Hepatology
ISSN : 2373-9487
Launched : 2013
Annals of Nursing and Practice
ISSN : 2379-9501
Launched : 2014
Author Information X