Ion Leaching Properties and Bio-Film Characteristics In Various Beverages - Paper Example

The in vitro study herein comparatively evaluated the ion leaching properties and bio-film characteristics of commercially available ceramics immersed in various beverages.

Methods

Fabricated biomaterials were immersed in different beverages. Spectroscopic methods enabled the evaluation of leaching properties of the restorations.

Results

The findings were tabulated.

Conclusions

The results showed that all the three groups of ceramics released different ions of varying quantities which had statistically significant difference among the various beverages and with the control. The surface changes also differed with the type of ceramic and test solution. Overall, carbonated drink resulted in more ion leaching (p< 0.05) and surface deterioration and Feldspathic and Pressable ceramic underwent more ion leaching (p< 0.05) and surface changes than CAD-CAM fabricated Zirconia for most of the elements.

Keywords

Feldspathic ceramic, Zirconium ceramic, Pressable ceramic, leaching.

Comparative Evaluation of Ion Leaching Properties and Bio-Film Characteristics of Commercially Available Ceramics Immersed In Various Beverages - An In-Vitro Study

1. Introduction

Dental conditions such as periodontal disease and dental caries have been significant causes of loss of teeth and tooth supporting structures. The conditions ultimately make a person psychologically and physically handicapped. The dental professions primary objectives are to rehabilitate and restore the dentition of patients in improving the comfort, function, and esthetics of the stomatognathic system. With the current advancements in material science and related technology, there is a revolutionary change in dentistry and modern living at large. Prosthodontics, an area that deals with the restoration of teeth and associated oral structures through artificial means, relies on the current material advancements.

Both the patient and dentist desire fixed replacement of teeth for many reasons such as strength and psychological comfort. Feldspathic porcelain, zirconium, and metal free ceramics find application in the fabrication of bridges and crowns. Selection of the biomaterial to use depends on the mechanical, esthetic, and biological factors which require proper diagnosis and treatment.

Computer Aided Designing and Computer Aided Manufacturing (CAD-CAM) currently plays a critical role in the fabrication of dental prosthesis. Results following CAD-CAM use show good marginal fit, less internal flaws, better adaptability, and precise contours.

The oral eco-system subjects the restorations and restorative materials to harsh mechanical, thermal, chemical, biologic, and thermal stresses. The stresses negatively influence the performance of materials in vivo. In clinical situations, the restorations come into contact with beverages and foods. Alcohol and carbonated drinks are beverages that are deleterious to teeth and general health. The beverages also impair the chemical structures of restoration materials which weakens them. Carbonated beverages soften and demineralize the enamel reducing its hardness. Also, they cause wear of porcelain.

There are several studies concerning the effect of acidic beverages on materials used in fabrication. However, few studies relate to ion leaching properties of ceramics under agents such as soda, citrate buffer, acetic acid, and distilled water. Therefore, the present research employed the use of three contemporary esthetic ceramic materials which include CAD-CAM fabricated ceramics (zirconia), metal ceramics (feldspathic porcelain), and pressable ceramic. The elements got exposed to carbonated beverages, artificial saliva, and alcoholic beverage. Also, the study included the degree of bacterial adhesion on ceramic surfaces.

Aims

I. To evaluate leaching of ions from various materials on exposure to agents such as saliva and beverages.

II. To compare the degree of ion leaching among the various biomaterials on exposure to multiple agents.

III. To evaluate surface characteristics of various materials following exposure to agents.

IV. To examine bacterial adherence on the surface of materials following exposure.

2. Materials and Methods

The in-vitro study centers on the comparative evaluation of bio-film and ion leaching properties of three commercially available ceramics that include pressable ceramic, zirconia, and feldspathic porcelain on immersion to carbonated drinks, artificial saliva, and alcohol.

An induction coupled plasma optical emission spectroscopy (ICP-OES) measured the amount of leached ions. A Ceramill Motion 2 (CAM) milling machine produced dental restorations by milling blanks of wax, zirconium oxide, and plastics.

2.1. Fabrication of custom-made stainless steel mold for condensing and packing feldspathic porcelain.

A stainless steel hollow custom and spherical mold were fabricated for condensing and packing the feldspathic porcelain. The frame was designed as a two-piece jig mechanism that could be assembled using vertical projection to facilitate easy retrieval of the fabricated specimen. The thickness of the disc specimen was 2mm with a diameter of 12mm.

2.2. Fabrication of feldspathic porcelain disks

Packing of the Dentin porcelain was done leaving spaces of about 1mm for Enamel. After condensation of the dentine material into the mold space, the disk was retrieved by pushing the inner mold into the outer shell placing over a tissue paper. The disc was transferred to the sintering furnace. Firing cycles started from 500 degrees Celcius with 6 minutes pre-drying time, followed by 7.49 min heating time at 55 degrees Celcius temperature rise till 930 degrees, then 1min holding in a vacuum. Second firing was done after adding the material to compensate for the first firing. Then there was corrective firing.

2.3. Fabrication of pressable ceramic discs using wax blanks milled in CAD-CAM

Ceramill MOTION 2 fabricated the wax blanks. The wax blanks were then invested and dewaxed. The ceramic ingots were pressed into the mold space. On completion of dewaxing, the pressable ceramic ingots were cast in the temperature range of 650-900 o C.

2.4. Fabrication of zirconia discs using CAD-CAM machine

The Zirconia discs were fabricated using the Ceramill MOTION 2 system. The proper orientation of mold and scanner was achieved then the die scanned. The zirconia discs were designed, milled and subjected to sintering.

2.5. Immersion of fabricated specimens in various beverages

Artificial saliva was prepared using 0.002g ascorbic acid, 0.580g sodium chloride, 0.030g glucose, 0.170g calcium chloride, 0.160g sodium thiocyanide, 0.160g ammonium chloride, 0.200g urea, 0.330g potassium pyrophosphate, and 2.700g mucin in 1000 ml of distilled water.

Each ceramic specimen was stored separately in individual containers containing 20ml of test solution. Six samples from each ceramic were immersed in each of the three test solutions and one control solution which was distilled water.

Ceramic discs from each group were randomly selected and immersed in the sterile container containing 20 ml of the various beverages. The samples were labeled and incubated at 37 degrees for one week. Then the beverages were digested for ICP-OES testing. The refreshments were separated from the sterile boxes. Carbonated drink, alcohol were kept in a water bath to reduce water content. The residue after complete evaporation was digested with nitric acid and hydrochloric acid. All the solutions were filtered entirely then introduced to ICP-OES machine.

2.6. Evaluation through ICP-OES

An adequate amount of each solution was fed into the nebulizer then the device activated with the plasma. Detection of excited photons helped determine the level of ions leached from the solution in parts per billion.

2.7. Bacterial adhesion assay

Five freshly prepared specimens from each category were autoclaved. Then four samples from each group were placed in newly prepared artificial saliva, carbonated drink, distilled water, and alcohol. The mixtures were incubated at 37 degrees for two hours. The fifth sample remained untreated for SEM examination.

Samples were collected and exposed to Streptococcus mutans in Brain Heart Infusion Broth at 35 degrees and 80 revolutions per minute overnight. The samples were later collected and washed off in phosphate buffer and fixed with 2.5% glutaraldehyde. The samples got dehydrated in ascending grades of ethyl alcohol and treated with isoamyl acetate for 10 minutes.

2.8. SEM analysis along with EDX-Spectroscopy

The samples were subjected to critical point drying followed by sputter coating with gold-palladium alloy and visualized under scanning electron microscope (Hitachi S-2400) along with the control sample that was previously segregated.

2.9. Tabulation of the results

The values obtained in ppb were converted into micrograms/cm2 by factoring the total surface area of each specimen which was 3.02 cm2. The radius was 6mm and height of 2mm. The formula used was:

Total surface area of cylinder=2prh + 2pr2

2.10. Statistical analysis

The tabulated data were analyzed using SPSS software version 20.0. A Kruskal-Wallis ANOVA test that followed a chi-square distribution was used. A P value of less than 0.05 at 95% confidence interval was considered significant.

Results

Table 1: Elemental ion composition of Feldspathic porcelain (Vita Vmk Master), Pressable ceramic (IPS e.max Press) and Zirconia (Ceramill ZI) from EDX - Spectroscopic study.

FELDSPATHIC PORCELAIN (Vita Vmk Master)

Element C O Na Al Si K CaBa Weight% 9.57 46.36 5.31 6.14 22.99 6.29 1.24 2.10 PRESSABLE CERAMIC ( IPS e.max Press)

Element O Na Al Si K CaTi Fe Zn

Weight% 50.31 6.64 9.13 25.85 4.68 1.42 0.39 0.61 0.97

ZIRCONIA ( Ceramill ZI)

Element C O Na Al Si K CaFe Zn

Weight% 9.18 47.09 7.58 7.71 22.30 3.41 1.57 0.25 0.90

Table 2: pH of the test solutions before and after sample immersion.

Sl.

No. Test solution Initial pH

(0 hrs) Final pH

(168 hrs) Ceramill ZI

(168hrs) IPS e.max Press

(168 hrs) Vita Vmk Master (168 hrs)

1. DISTILLED WATER 6.85 6.98 7.09 7.16 7.10

2. ARTIFICIAL SALIVA 5.89 6.15 7.19 7.26 7.23

3. CARBONATED DRINK 2.35 2.46 3.04 3.08 2.98

4. ALCOHOL 3.92 3.88 4.73 4.85 5.13

Table 3: Baseline ion composition of the test solutions (ppb).

Sl.NoTest solution HrsAl Ba Mg MnZn ZrLi Y Na K Ca1. DISTILLED WATER 0 0 0 0 0 0 0 0 0 0 0 800

2. ARTIFICIAL SALIVA 0 119 72 1844 17.8 134 0 10.4 0 239200 550833 18307

3. CARBONATED DRINK 0 157 74.8 10086 65 182 3.9 19.5 0 1900 37901 13629

4. ALCOHOL 0 231 56.4 500 20.8 121 0 29.3 0 6767 0 1561

Table 4: Mean elemental ion release from three test groups immersed in distilled water (ug/cm2).

Hours Al Ba Mg MnZn ZrLi Y Na K CaDISTILLED WATER 0 0 0 0 0 0 0 0 0 0 0 800

FELDSPATHIC

PORCELAIN

(VITA VMK

MASTER)

168

155.00 76.82 704.83 29.85 126.03 3.47 79.73 .00 4094.50 .00 6694.50

NET(ppb)

155.00 76.82 704.83 29.85 126.03 3.47 79.73 .00 4094.50 .00 5894.50

ug/cm2

51.32

25.44

233.39

9.88

41.73

1.15

26.40

.00

1355.8

.00 1951.82

PRESSABLE CERAMIC

(IPS e.max

Press)

168

126.67 30.43 150.67 16.53 82.98 3.12 352.50 .00 5127.83 .00 6429.00

NET(ppb)

126.67 30.43 150.67 16.53 82.98 3.12 352.50 .00 5127.83 .00 5629.00

ug/cm2

41.94

10.08

49.89

5.47

27.48

1.03

116.72

.00

1697.96

.00 1863.91

ZIRCONIA

(Ceramill ZI)

168

161.17 78.67 720.67 35.90 103.17 6.13 109.33 .00 5883.33 .00 10439.67

NET(ppb)

161.17 78.67 720.67 35.90 103.17 6.13 109.33 .00 5883.33 .00 9639.67

ug/cm2

53.37

26.05

238.63

11.89

34.16

2.03

36.2

.00

1948.12

.00 3191.94

Table 5: Mean elemental ion release from three test groups immersed in artificial saliva (ug/cm2).

Hours Al Ba Mg MnZn ZrLi Y...