저 시-비 리- 경 지 2.0 한민

는 아래 조건 르는 경 에 한하여 게

l 저 물 복제, 포, 전송, 전시, 공연 송할 수 습니다.

다 과 같 조건 라야 합니다:

l 하는, 저 물 나 포 경 , 저 물에 적 된 허락조건 명확하게 나타내어야 합니다.

l 저 터 허가를 면 러한 조건들 적 되지 않습니다.

저 에 른 리는 내 에 하여 향 지 않습니다.

것 허락규약(Legal Code) 해하 쉽게 약한 것 니다.

Disclaimer

저 시. 하는 원저 를 시하여야 합니다.

비 리. 하는 저 물 리 목적 할 수 없습니다.

경 지. 하는 저 물 개 , 형 또는 가공할 수 없습니다.

Effect of pH and concentrations of

ethanol on surface change

and color stability of heat-activated

denture base resin

Youn-Hee Hong

Department of Dentistry

The Graduate School, Yonsei University

Effect of pH and concentrations of

ethanol on surface change

and color stability of heat-activated

denture base resin

Directed by Professor Kwang-Mahn Kim

The Master's Thesis

submitted to the Department of Dentistry,

the Graduate School of Yonsei University

in partial fulfillment of the requirements

for the degree of Master of Dentistry

Youn-Hee Hong

June 2016

ACKNOWLEDGEMENTS

연 학 치과 학 치과생체재 공학 실 입학 합격 식을 듣고 뛸 듯이

기뻐하 기억이 어제 일처럼 생생한 어느 졸업이 눈앞에 다가 고 저의

사학위 논문이 결실을 맺게 되었습니다.

저, 이 논문이 되기까 아낌없는 조언과 애정 어린 심으 해

주 수님께 깊은 감사를 드립니다.

또한, 자신감 잃 않 기를 아주시고 가르침을 주신 김경남

수님께 감사 드립니다.

뿐만 아니 , 본 논문을 하게 주시어 결과물이 잘 마무리될 수 있

이끌어주신 보철과 문홍 수님께 감사를 드립니다.

어, 초심을 잃고 힘들어하 저에게 끊임없이 힘이 되어주고 많은

을 주신 실 생님들과 친 들 두 감사합니다.

마 막으 제가 학위를 무사히 마칠 수 있 에 응 해주시고 믿고

켜 주신 사 하는 님과 언니에게 이 논문을 칩니다. 사 합니다.

i

TABLE OF CONTENTS

LIST OF FIGURES ····································································ⅲ

LIST OF TABLES ······································································ⅳ

ABSTRACT ·············································································ⅴ

I. INTRODUCTION ···································································· 1

1.1. Color stability ······································································ 2

1.2. Surface roughness ································································· 2

1.3. Originality of this study··························································· 2

1.4. Aims of this study ································································· 3

II. MATERIALS AND METHODS ·················································· 4

1. Material ··············································································· 4

1.1. Specimen preparation··························································· 5

1.2. Immersion solution ····························································· 5

2. Method················································································ 5

2.1. Color change measurement ···················································· 6

2.2. Surface roughness······························································· 7

2.3. Surface morphology ···························································· 7

2.4. Statistical analysis······························································· 7

ii

III. RESULTS ············································································ 8

1. Color change measurement ························································· 8

2. Surface roughness ··································································· 9

3. Surface morphology································································10

IV. DISCUSSION ·······································································11

V. CONCLUSION ······································································13

VI. REFERENCE·······································································14

ABSTRACT (IN KOREAN) ························································18

iii

LIST OF FIGURES

Figure 1. Denture base resin in metal flask ································4

Figure 2. Prepared specimens ······················································4

Figure 3. SEM (200x) of specimen flat surfaces following immersion

in each solution for 10 days ········································· 10

iv

LIST OF TABLES

Table 1. Materials used in study ·············································4

Table 2. Control and experimental group···································6

Table 3. The mean values of standard deviations of color differences

(ΔE) compared with control ·······································8

Table 4. The mean values of standard deviations SDs of Ra (㎛) ······9

v

ABSTRACT

Effect of pH and concentrations of ethanol on surface change

and color stability of heat-activated denture base resin

Youn-Hee Hong

Department of Dentistry

The Graduate School, Yonsei University

(Directed by Professor Kwang-Mahn Kim, D.D.S., Ph.D.)

Complete dentures are mostly fabricated by using acrylic resin. Consumption of

certain beverages may affect the esthetic and physical properties of acrylic resin.

Due to its low pH, ethanol can produce erosion and alter some properties of

acrylic resin, as well. This study evaluated the change in surface and color of

conventional heat-activated denture base resin by subjecting it to different pH and

concentrations of ethanol at different time intervals.

A heat-activated denture base resin (SR Triplex Hot, Ivoclar Vivadent,

Liechtenstein, Europe) was used as a material of this study. Fifty specimens (20

mm x 20 mm x 2 mm) were prepared by manufacturer’s instruction and divided

into 5 groups which were a control group (PBS, pH 7.4), group 1 (PBS + HCl, pH

4.0), group 2 (PBS + NaOH, pH 10.0), group 3 (PBS + Ethanol, ethanol

vi

concentration 20 %) and group 4 (PBS + Ethanol, ethanol concentration 40 %) for

each test solution. All groups were mixed with green pigment and prepared as the

test solutions. The specimens were immersed into the groups at 37 ℃ and stored

for 10 days. After 5 and 10 days of immersion, the surface roughness (Ra) and

color difference (ΔE) of the specimens were measured. The color change was

checked by a Spectrophotometer (CM-3500d, MINOLTA, Japan) using a CIE Lab

system. The surface roughness tester (Mitutoyo Corp, Kawasaki, Japan) was used

to measure the surface roughness of the specimens and the surface morphologies

were observed by SEM.

According to the results of color change, no significant difference was observed

among groups at T1 (p>0.05). However, group 4 at T2 showed significant

difference that compared with the other groups (p<0.05). There was significant

different between T1 and T2 in group 4 (p<0.05).

When surface roughness of groups analyzed, the highest surface roughness was

observed in group 4 followed by group 3 at T2. However, group 4 was only found

significant difference at T1 (p<0.05). There was no significant different between

the pH variations groups (group 1 and 2) and the control group (p>0.05). The

surface became rougher with time in group 3, 4 (p<0.05).

SEM evaluation at 200 x magnification showed a slightly more irregular surface

in group 3 and a distinct irregular feature in group 4.

From the obtained results, it was concluded that denture base resin is not

recommended to immerse in ethanol for cleaning and disinfection.

Key words: heat-activated denture base resin, color change, surface roughness,

surface change, pH, ethanol

- 1 -

Effect of pH and concentrations of ethanol on surface change

and color stability of heat-activated denture base resin

Youn-Hee Hong

Department of Dentistry

The Graduate School, Yonsei University

(Directed by Professor Kwang-Mahn Kim, D.D.S., Ph.D.)

I. INTRODUCTION

Complete dentures are mostly fabricated by using acrylic resin because it is a low cost

material that requires relatively easy manipulation and construction methods. However, it

is not the ideal material in every respect (Shotwell et al., 1992). A drawback of this

material is that its esthetic, physical, and mechanical properties change rapidly over time

in the oral environment. (Keyf and Etikan, 2004). Consumption of certain beverages may

affect the esthetic and physical properties (Dietschiet al., 1994) of the acrylic resin. Due

to its low pH, ethanol can produce erosion and alter some properties of acrylic resin, as

well. The chemicals in beverages can lead to wear and surface degradation of acrylic

resin, resulting in unaesthetic external pigmentation, such as, stains (Sarret et al., 2000).

- 2 -

1.1 Color stability

Staining of acrylic resin can lead to esthetic problems. denture base polymers should

have a smooth and glassy surface and be capable of matching the natural appearance of

soft tissues. The material should be translucent for the best esthetic effect. Color and

translucency should be maintained during processing, and acrylic resin should not

become stained and not change color in clinical use (Hersek et al., 1999). Color change of

prosthodontic materials may result in patient dissatisfaction and additional expense for

replacement (Sham et al., 2004).

1.2 Surface roughness

The roughened surface may accumulate plaque. A high percentage of elderly people

consume ethanol containing beverages (Kirchner et al., 2007). Ethanol is present in

several drinks and has been shown to soften the denture base PMMA (Hargreaves, 1981).

Ethanol is also thought to act as a plasticizer of the polymer matrix (Ferracane and

Marker, 1994).

1.3 Originality of this study

Although there have been some studies on the color stability of acrylic resin denture

bases (Lai, 2003), the comparison of these resins was after immersion in beverages such

as cola and red wine. However, these beverages have different composition. For example,

Cola gains its color through the addition of caramel, which exhibits colors ranging from

the palest yellow to the deepest brown and is made by heating sugar or glucose in the

presence of alkali or mineral acid (Patel, 2004). Also, cola has the low pH and it may

damage the surface of the materials. Therefore, it is difficult to determine the direct cause

of the color stability with those studies.

- 3 -

1.4 Aims of this study

The aim of the present study was to analyze the change in surface and the color stability

of conventional heat-activated denture base resin by subjecting it to different pH and

concentrations of ethanol and to find possible co-relation between the change in the

surface roughness and the color stability.

The null hypotheses were that (1) there would be no significant difference in the color

change and the surface roughness in the pH variations and concentrations of ethanol and

(2) there would be no relationship between the color change and the surface roughness.

- 4 -

II. MATERIALS AND METHODS

1. Material

Table 1. Materials used in study

Material Product Manufacturer

Heat-activated denture base

resin

SR Triplex Hot Ivoclar

Vivadent

Coloring agent Tempera Shield

Buffering solution Phosphate buffered saline (PBS) pH 7.4 Gibco

Acid Hydrochloric acid (HCl) Duksan

Alkali Sodium Hydroxide (NaOH) Duksan

Ethanol Ethyl Alcohol 99.9% (Ethanol) Duksan

Fig 1. Denture base resin in metal flask. Fig 2. Prepared specimens.

- 5 -

1.1 Specimen preparation

In this study, a heat-activated denture base resin (SR Triplex Hot, Ivoclar Vivadent,

Liechtenstein, Europe) was used to prepare the specimens. The heat-activated denture

base resin was mixed according to the powder / liquid ratio (23.4 g / 10 ml) recommended

by the manufacturer. It was then molded in a flask filled with gypsum (Fig. 1), and the

stone surfaces coated with a separator. The material was polymerized in a water bath

according to the manufacturer’s recommendations - heat up to 100 ℃ and let boil for 45

minutes. The specimens were placed cool at room temperature for 30 minutes.

Subsequently, the flask was completely cooled with cold water. After deflasking, the

specimens were abraded on both sides with no. 600 grit silicone sand paper. Slurry of

water and pumice was applied to surfaces of the specimens with a brush wheel. Fifty

specimens (Fig. 2) were made and the size of each square shape specimen was 20 mm x

20 mm x 2 mm.

1.2 Immersion solution

The 50 ml of solutions that were pH 4.0 (PBS + HCl), pH 10.0 (PBS + NaOH), ethanol

concentration 20 % (PBS + Ethanol), ethanol concentration 40 % (PBS + Ethanol) and

pH 7.4 (PBS) were prepared for immersion of the specimens and mixed with 5 ml of

green pigment which was a complementary color of the denture base resin to check the

color change (Table 1). The pHs were checked by a digital pH-meter (Orion 4 star,

Thermo Fisher scientific Inc., Singapore).

2. Method

The specimens were first divided into 5 groups for each test solution (Table 2), then for

each solution 10 specimens were coded, from 1 to 10, on the back of the specimens. They

were immersed individually in 5 ml of each solution at 37℃ and stored for 10 days.

- 6 -

Table 2. Control and experimental group

Group property Remark

Control pH 7.4 -

1 pH 4.0 experimental group

2 pH 10.0 experimental group

3 ethanol concentration 20% experimental group

4 ethanol concentration 40% experimental group

After 5 days (T1) and 10 days (T2) immersion, the specimens were rinsed with distilled

water for 3 minutes and blotted dry with tissue paper before color stability and surface

roughness measurement.

2.1 Color change measurement

The color of control group was measured before the calculation of color differences

(ΔE) of group 1 to 4. Then, the colors of specimens of group 1 to 4 were measured with a

spectrophotometer (CM-3500d, MINOLTA, Japan). Color differences (ΔE) between

control group and group 1 to 4 were calculated automatically by the appliance,

represented by the formula:

ΔE* = [(ΔL*)2+(Δa*)2+(Δb*)2] ½

Before each measurement, the spectrophotometer was calibrated according to the

manufacturer's recommendations. The measurement mode was light reflective and the

diameter was 8 mm. L∗ refers to the lightness coordinate, and its value ranges from zero

(black) to 100 (white). The a∗ and b∗ are chromaticity coordinates in the red-green axis

and the yellow-blue axis, respectively. Positive a∗ values indicate a shift to red, and

negative values indicate a shift to green. Similarly, positive b∗ values indicate the yellow

color range, and negative values indicate the blue color range (Guler et al., 2005). The

center of specimens was measured and the mean values of the ΔE data were calculated.

- 7 -

2.2 Surface roughness

The surface roughness tester SJ-400 (Mitutoyo Corp, Kawasaki, Japan) was used to

measure the specimens’ surface roughness. The profiler was set to move a diamond stylus

across the specimen surface under a constant load of 4 mN.

The surface roughness was measured with a linear variable differential transformer. The

surface roughness was derived from computing the numerical values of the surface

profile. The Ra value describes the overall roughness of a surface and is defined as the

mean value of all absolute distances of the roughness profiles from the mean line within

the measuring distance. 4.0 mm of each scanning line was carried out for each specimen

in 3 randomly selected areas. The mean Ra was calculated from three lines as the mean

roughness of the specimen.

2.3 Surface morphology

A specimen of each group (Table 2) was selected after 10 days immersion for further

study. These specimens were subsequently processed for SEM. One of the flat surfaces

was coated with gold and observed in a scanning electron microscope (AIS2300C, Seron

technologies, Inc., Gyeonggi-Do, Korea).

2.4 Statistical analysis

One-way, ANOVA was used to evaluate the effect of pH and ethanol between the groups

with the same immersion time, and the influence of different immersion time in the same

group. The relationship between color stability and surface roughness over time was

analyzed with two-way ANOVA. Mean values were compared by the Tukey HSD test

(p<0.05).

- 8 -

III. RESULTS

1. Color change measurement

The color differences (ΔE) of the specimens after T1 and T2 of immersion in the solutions are presented in Table 3, as well as the differences among groups.

Table 3. The mean values and standard deviations of color differences (ΔE) compared

with control

Group T1 T2

1 1.13 (0.54)aA 1.37 (0.87)aA

2 1.35 (0.77)aA 1.56 (0.49)aA

3 1.75 (0.64)aA 2.18 (0.61)aA

4 1.88 (0.45)aA 5.91 (2.47)bB

See Table 2 for meaning of each group

a. b: Different letters indicate dissimilarity in same groups (p<0.05)

A. B: Different letters indicate dissimilarity in same immersion time (p<0.05)

T1: 5 days. T2: 10 days

”()”: standard deviation

According to the results, no significant difference was observed among groups at T1

(p>0.05). However, group 4 at T2 showed significant difference that compared with the

other groups in color change (p<0.05). There was significant different between T1 and T2

in group 4 (p<0.05).

- 9 -

2. Surface roughness

Surface roughness tester measured the difference in the surface roughness of each group

at T1 and T2. According to the ANOVA results, mean values and SDs of surface roughness

(Ra) and group differences are listed in Table 4, respectively.

Table 4. The mean values and standard deviations of Ra (㎛)

Group T1 T2

control 0.05 (0.007)aA 0.05 (0.009)aA

1 0.04 (0.006)aA 0.05 (0.007)aA

2 0.05 (0.007)aA 0.05 (0.011)aA

3 0.06 (0.012)aA 0.15 (0.028)bB

4 0.12 (0.020)aB 0.24 (0.057)bC

See Table 2 for meaning of each group

a. b: Different letters indicate dissimilarity in same groups (p<0.05)

A. B. C: Different letters indicate dissimilarity in same immersion time (p<0.05)

T1: 5 days. T2: 10 days

”()”: standard deviation

The highest surface roughness was observed in group 4 followed by group 3 at T2

(p<0.05). However, group 4 was only found significant difference at T1 (p<0.05). There

was no significant different between the pH variations groups (group 1 and 2) and the

control group (p>0.05). The surface became rougher with time in group 3 and 4 (p<0.05).

- 10 -

3. Surface morphology

Before immersion Control

Group 1 Group 2

Group 3 Group 4

Fig 3. SEM (200x) of specimen flat surfaces following immersion in each solution for 10

days.

Fig 3 presents a micrograph illustrating surface characteristics after immersion in each

group. SEM evaluation at 200 x magnification showed a smooth aspect for the specimens

immersed in group 1 and 2. However, a slightly more irregular surface was found for

group 3 and a distinct irregular feature was evident for acrylic resin submitted to

immersion in group 4.

- 11 -

IV. DISCUSSION

Acrylic resin has been used since 1937 for making denture bases, and the most widely

used material is poly-methyl methacrylate (PMMA) (Lai et al., 2004, Machado et al.,

2007). Polymerization is an exothermic reaction by addition, consisting of the bond

between monomers, resulting in a single polymeric macromolecule characterized by its

high molecular weight. The chemical reaction of acrylic resin polymerization is

exothermic, which may be initiated by chemical substances, light and heat supplied by

heated water or microwave energy (Phillips, 1993), and these methods are routinely used

in denture laboratories (Anusavice, 1998).

This study was to evaluate the effect of pH and ethanol contents similar to the

concentration of alcoholic beverages on surface and color of conventional heat-activated

denture base resin. The denture base resins have been reported to be critical in color

stability, which is affected by different alcohol concentrations and pH solutions (Patel et

al., 2004). Several studies have reported that alcohol facilitates staining by softening the

resin matrix. Therefore, it could be possible that the alcohol component roughened the

denture base resin surfaces, thereby resulting in increased staining (Patel et al., 2004).

In this study, the roughness parameter (Ra) was analyzed, because it represents the

arithmetic mean of all the roughness values within the covered space on a certain

surface. Therefore, Ra is the most indicated value (Joniot et al., 2006, Türkün and Türkün,

2004). Also, the CIE Lab system for measuring chromaticity was chosen to record color

differences as it is well suited for the determination of small color differences (Khokhar et

al., 1991). If a material is completely color stable, no color difference will be detected

after its exposure to the testing environment (ΔE=0). Various studies have reported

different thresholds of color-difference values above which the color change is

perceptible to the human eye. These values of ΔE ranged from equal to 1 (Seghi et al.,

- 12 -

1989), between 2 and 3 (Ruyter et al., 1987), greater than or equal to 3.3 (Johnston and

Kao, 1989), and greater than or equal to 3.7 (Okubo et al., 1998). Values of ΔE between 0

and 2 were imperceptible, values of ΔE in the range of 2 to 3 were just perceptible, values

from 3 to 8 were moderately perceptible, and values above 8 were markedly perceptible

(Gross and Moser, 1977). A ΔE value of 3.7 or less was considered to be clinically

acceptable (Okubo et al., 1998, Johnston and Kao, 1989). In this study, except for group 4

at T2 (ΔE=5.91), the color changes exhibited by all specimens are at clinically acceptable

levels (ΔE≤3.7).

According to the results of this study, the specimens became significantly stained and

rougher after they were immersed in ethanol group 3 and 4. This result showed that there

was a co-relation between color stability and surface roughness. Also, as the immersion

time increased, the changes became more severe.

The denture may function as a reservoir of infection, and surface irregularities would

increase the likelihood of microorganisms remaining on the surface after the prosthesis

has been cleaned (Azevedo et al., 2006, Yannikakis et al., 2002). This roughened surface

may cause plaque accumulation as well as staining. This concept is of clinical importance

because patients need to have a smooth surface to deter the formation of a biofilm. This is

an aesthetic concern as well as an overall concern for maintaining good oral hygiene

(Berger et al., 2006). The roughness of the acrylic resin surfaces is of considerable

importance, as microorganism adhesion to a surface is a pre-requisite for the colonization

of this surface, reducing the mechanical properties of the denture base such as hardness

and flexural strength (Bafile et al., 1991). Therefore, further study should be tested to see

if any correlation exists between the microorganism adhesion to a surface and the

mechanical properties of denture base resin.

- 13 -

V. CONCLUSION

From the results obtained, and within the limitations of the study, it was concluded that:

(1) .pH did not affect both color and surface change.

(2) Specimens which were immersed in high concentrations ethanol (40%) for 10 days

showed significant change in color and surface roughness.

(3) Surface of specimens which were immersed in ethanol became rougher with time.

(4) Specimens which were immersed in high concentrations ethanol (40%) showed

significant color difference with time.

Therefore, denture base resin is not recommended to immerse in ethanol for cleaning

and disinfection.

- 14 -

VI. REFERENCES

Anusavice KJ (1998). Phillips – Materiais Dentários, 10 edn. Rio de Janeiro:

Guanabara-koogan 271.

Azevedo A, Machado AL, Vergani CE, Giampaolo ET, Pavarina AC, Magnani R (2006).

Effect of disinfectants on the hardness and roughness of reline acrylic resins.

J Prosthodont 15:235–242.

Bafile M, Graser GN, Myers ML, Li EKH (1991). Porosity of denture resin cured

by Microwaveenergy. J Prosthet Dent 66:269–274.

Berger JC, Driscoll CF, Romberg E, Luo Q, Thompson G (2006). Surface

roughness of Denture base acrylic resins after processing and polishing.

J Prosthodont 15:180–186.

Dietschi D, Campanile G, Holz J, Meyer JM (1994). Comparison of the color

stability of Tennew-generation composites: An in vitro study. Dent Mater

10:353-62.

Ferracane JL, Marker VA (1994). Solvent degradation and reduced fracture toughness in

agedcomposites. J Dent Res 92:257–61.

Gross MD, Moser JB (1977). A colorimetric study of coffee and tea staining of four

composite resins. J Oral Rehabil 4:311–322.

- 15 -

Guler AU, Yilmaz F, Kulunk T, et al (2005). Effects of different drinks on

stainability of Resin composite provisional restorative materials. J Prosthet Dent

94:118-124.

Hargreaves AS (1981). The effect of the environment on the crack initiation

toughness of dentalpoly(methyl methacrylate). J Biomed Mater Res 15:757-768.

Hersek N, Canay S, Uzun G, et al (1999). Color stability of denture base acrylic

resins in three food colorants. J Prosthet Dent 81:375-379.

Johnston WM, Kao EC (1989). Assessment of appearance match by visual observation

and clinical colorimetry. J Dent Res 68:819–822.

Joniot S, Salomon JP, Dejou J, Grégoire G (2006). Use of two surface analyzers

to evaluate thesurface roughness of four esthetic restorative materials after

polishing. Operat Dent 31:39–46.

Keyf F, Etikan I (2004). Evaluation of gloss changes of two denture acrylic resin

materials In four different beverages. Dent Mater 20:244-251.

Khokhar ZA, Razzoog ME, Yaman P (1991). Color stability of restorative resins.

Quintessence Int 22:733–737.

Kirchner JE, Zubritsky C, Cody M, et al (2007). Alcohol consumption among older adults

in primary care. J Gen Intern Med 22:92-97.

Lai CP, Tsai MH, Chen M, Chang HS, Tay HH (2004). Morphology and

properties of Dentureacrylic resins cured by microwave energy and conventional

water bath. Dent Mater 20:133–141.

- 16 -

Lai YL, Lui HF, Lee SY (2003). In vitro color stability, stain resistance, and water

sorption of four removable gingival flange materials. J Prosthet Dent 90:293-300.

Machado C, Sanchez E, Shereen SA, Uribe JM (2007). Comparative study of the

Transverse strength of three denture base materials. J Dent 35(2):930–933.

Okubo SR, Kanawati A, Richards MW, Childress S (1998). Evaluation of visual and

instrument shade matching. J Prosthet Dent 80:642–648.

Patel SB, Gordan VV, Barrett AA, et al (2004). The effect of surface finishing and

storage solutions on the color stability of resin-based composites. J Am Dent Assoc

135:587-594.

Phillips RW (1993). Skinner Materiais Dentários, 9 edn. Rio de Janeiro:

Guanabara – Koogan. Ruyter IE, Nilner K, Moller B (1987). Color stability of

dental composite resin materials for crown and bridge veneers. Dent Mater

3:246–251.

Sarret DC, Coletti, Peluso AR (2000). The effect of alcoholic beverages on

composite wear. Dent Mater 16:62-7.

Seghi RR, Hewlett ER, Kim J (1989). Visual and instrumental colorimetric assessments

of small color differences on translucent dental porcelain. J Dent Res 68:1760–1764.

Sham AS, Chu FC, Chai J, et al (2004). Color stability of provisional prosthodontic

materials. J Prosthet Dent 91:447-452.

Shotwell JL, Razzoog ME, Koran A (1992). Color stability of long-term soft denture

liners. J Prosthet Dent 68:836-8.

- 17 -

Türkün LS, Türkün M (2004). Effect of bleaching and repolishing procedures on

coffee and Tea stain removal from three anterior composite veneering materials.

J Esthet Restor Dent 16:290–301.

Yannikakis S, Zissis A, Polyzois G, Andreopoulos A (2002). Evaluation of

porosity in microwave-processed acrylic resin using a photographic method.

J Prosthet Dent 87:613–619.

- 18 -

ABSTRACT (IN KOREAN)

pH 에탄 도가 열중합 치상 진 변

색 안 에 미치는 향

<지도 수 만>

연 학 학원 치 학과

연

치는 아크릴릭 진 사 하여 다. 그러나 재

료 문 강 경에 따라 심미 , 물리 물 변 가

루어진다는 것 다. 특 료 비는 아크릴릭 진 심미

과 물 에 향 미칠 수 고 는 낮 pH 함 에탄

하여 아크릴릭 진 식과 물 변 에 해 초래 수

다.

따라 본 연 pH 에탄 도에 따라 열중합 치상

진 과 색 변 연 하는 것 다.

- 19 -

열중합 치상 진 (SR Triplex Hot, IvoclarVivadent,

Liechtenstein, Europe) 사 하여 50개 시편 (20 mm x 20 mm x 2

mm) 사 지시에 따라 하 고 각각 5개 그룹 10개씩

나누었다. (PBS, pH 7.4), 1 (PBS + HCL, pH 4.0), 2 (PBS +

NaOH, pH 10.0), 3 (PBS + 20% Ethanol) 그리고 4 (PBS + 40%

Ethanol)에 초 색 색 어 침 할 액 준비하 고

시편 각각 액에 침 하여 37℃ 암실에 10 간 보 하 다.

5 과 10 간 침 후, 각 시편 거칠 (Ra) 색 변 (ΔE)

측 하 다. 색 변 는 도계(CM-3500d, MINOLTA, Japan)

CIE Lab system 사 하여 하 고, 과 색 차 계산하

다. 거칠 는 도측 (Mitutoyo Corp, Kawasaki, Japan)

사 하여 측 하 SEM(scanning electron microscope)

태 찰하 다.

색 변 측 결과, T1에 는 실험 간에 한 차 가 지 않았

나 (p>0.05), T2에 는 4 에 다 실험 과 한 차 보

다 (p<0.05). 또한, 4 에 는 T1과 T2 사 에도 한 차가 나타났다

(p<0.05). 거칠 결과에 따 , T2에 는 3 과 4 에 한

차 하 고 4 > 3 순 거칠 값 아 나, T1에 는 4

에 만 한 차가 나타났다 (p<0.05). pH 한 1 과 2 에 는

과 한 차 가 없었다 (p>0.05). T1과 T2 비 시에는, 3 과

4 에 거칠 값 시간에 따라 증가하는 것 하 다

(p<0.05). SEM 결과, 3 과 4 에 변 양상 보 다.

- 20 -

색 변 거칠 에탄 에 침 에 많 변 보

, 상 결과 치상 진 사 시 척과 독 해 에

탄 에 담가 지 말 것 한다.

핵심 는 말: 열중합 치상 진, 색변 , 거칠 , 변 , pH, 에탄