Inhibition of denture plaque by TiO2 coating on denture base resins in the mouth

Inhibition of denture plaque by TiO2 coating on denture base resins in the mouth

RESEARCH AND EDUCATION Inhibition of denture plaque by TiO2 coating on denture base resins in the mouth Tomokuni Obata, DDS, PhD,a Takayuki Ueda, DDS...

2MB Sizes 0 Downloads 0 Views

RESEARCH AND EDUCATION

Inhibition of denture plaque by TiO2 coating on denture base resins in the mouth Tomokuni Obata, DDS, PhD,a Takayuki Ueda, DDS, PhD,b and Kaoru Sakurai, DDS, PhDc Denture plaque may cause ABSTRACT denture stomatitis and/or aspiStatement of problem. Information is lacking about antiadhesion effect of titanium dioxide (TiO2) ration pneumonia.1 Denture coating on denture base resins in the mouth. cleaning tends to be inadequate Purpose. The purpose of this clinical study was to investigate the antiadhesion effect of TiO2 in the elderly and people coating on denture base resins. requiring nursing care, resultMaterial and methods. Ten healthy dentate participants (mean 27 ±2 years of age) participated in ing in excessive denture plaque this study. Disks and palatal appliances were made with denture base resin. They were divided into accumulation.2,3 2 groups: a TiO2-coated group and an uncoated group. A primer and a top coat containing TiO2 The high photocatalytic were applied to the surfaces of the resin by means of an air spray. In the denture plaque staining and superhydrophilic effects of test, resin disks were fixed to the retainer, placed in each participant’s mouth for 3 days, and stained titanium dioxide (TiO2) have with a dental plaque-disclosing solution. The staining rate was calculated. The resin disks and been reported, and when palatal appliances were used to measure the total number of microbes. The resin specimens were placed in each participant’s mouth for either 3 or 7 days and swabbed to count the total applied to dentures, they can number of microbes. The chewing gum adherence test was performed both subjectively and be cleaned simply by rinsing in objectively. Subjectively, each participant wearing a palatal appliance rated adherence using a water.4-7 Two methods have visual analog scale. The objective test was performed with a chewing gum adhesion test. The been proposed for the applistaining rate, the total number of microbes, and the visual analog scale values were statistically cation of TiO2 to the denture analyzed using the Wilcoxon signed rank test, and the adhesive force was statistically analyzed base. One method is to mix using a Student t test. TiO2 with resin.8-10 This Results. In the denture plaque staining test, the measurement of microbes, and the resin chewing approach causes weakening gum adherence test results, significant differences were observed between the TiO2-coated groups and color change (whitening) and the uncoated groups. of the denture base. A preferConclusions. TiO2 coating of the denture base acrylic resin inhibited the adhesion of microbes, able option is to use the TiO2 denture plaque, and highly adhesive food. (J Prosthet Dent 2017;-:---) coating method. Here, the photocatalytic effect may be TiO2 coating. Moreover, Amano et al6 reported that applied to the denture without changing the mechanical durability of TiO2 coating with a primer against 100 000 properties or color of the denture base. brushstrokes could be achieved. Mori et al7 reported that The spray method with primer for TiO2 coating was 4-7,11 4 TiO2 coating increased resin gloss without causing color previously used. Kado et al showed that bolus change. adhesion can be reduced by TiO2 coating. Arai et al5 Based on experiments in animals, Tsuji et al11 observed that adhesion of Streptococcus sanguinis and reported that the TiO2 coating of denture base acrylic Candida albicans to the denture base can be inhibited by

a

Postgraduate student, Department of Removable Prosthodontics and Gerodontology, Tokyo Dental College, Tokyo, Japan. Associate Professor, Department of Removable Prosthodontics and Gerodontology, Tokyo Dental College, Tokyo, Japan. c Professor, Chair, Department of Removable Prosthodontics and Gerodontology, Tokyo Dental College, Tokyo, Japan. b

THE JOURNAL OF PROSTHETIC DENTISTRY

1

2

Volume

Clinical Implications TiO2 coating of the denture base acrylic resin applied by spray inhibited the adhesion of microbes, denture plaque, and adhesive food. Coating a denture may improve ease of denture cleaning. This is importance for older people and those requiring nursing care.

resin did not irritate the oral mucosa or cause skin sensitization. These inhibitory effects against the adhesion of the bolus, S sanguinis, and C albicans are in vitro results. Before the clinical application of TiO2 coating, the adhesion inhibitory effect against nonspecific microbes and denture plaque must be confirmed by placing resin in the mouth. Therefore, the purpose of this study was to evaluate the antiadhesion effects of TiO2 coating on denture base acrylic resin in the mouth. The null hypothesis was that no significant difference would be found between TiO2-coated resin specimens and uncoated resin specimens concerning microbial adhesion. MATERIAL AND METHODS To evaluate the antiadhesion effects of TiO2 coating on denture base acrylic resin in the mouth, 3 tests were performed: a denture plaque-staining test, a total microbial measurement test, and a chewing gum adherence test. The participants were 10 healthy dentulous adults without dental caries or periodontal disease. This study was approved by the Ethics Committee of Tokyo Dental College (no. 471). Acrylic resin (Procast DSP A2 and Acron No. 3; GC Corp) specimens for the experiment were polished using a series of abrasive paper (up to #1000 grit). In the uncoated group, the surface of the resin specimens was polished until buffing. In the TiO2coated group, the resin specimens were coated with TiO2 by using the following method. A primer (Paltitan PTI5603S; Nihon Parkerizing Co Ltd) was sprayed for 2 seconds, using an air brush (Super Airbrush Advance; WAVE), and was allowed to dry at 70 C for 10 minutes. Then, a top coat containing a TiO2 coating material (Paltitan PTI5603S; Nihon Parkerizing) was sprayed for 2 seconds and was allowed to dry at 70 C for an additional 10 minutes. The TiO2 crystals of the Paltitan used in this experiment were anatase type and 5 to 10 nm in diameter. A retainer for the denture plaque staining test was prepared by pressing 1-mm-thick polyethyleneterephthalate (Splint Square; Yamahachi Dental Mfg Co) to the participant’s maxillary cast. The white denture base resin disks, 5 mm in radius and 1 mm in thickness, were prepared using a denture base acrylic resin (Procast DSP A2; GC Corp). These were placed at the buccal areas THE JOURNAL OF PROSTHETIC DENTISTRY

-

Issue

-

of left and right maxillary premolars and molars on the retainer. Two disks in each group (4 disks in total) were placed on each retainer, using an autopolymerizing resin (Unifast III; GC Corp) (Fig. 1A, B). The disks were divided into 2 groups: TiO2-coated group and uncoated group. The disks on the retainer were placed in the mouth of each participant for 3 days. Participants were instructed to remove the retainer and immerse it in water when eating, brushing, and sleeping. After 3 days, the disks were stained with a dental plaque-disclosing solution (GUM Red-Cote #802; Sunstar Americas Inc) and photographed using a digital camera (D3100; Nikon Corp). From the images obtained, the percentage of the stained area relative to the disk area (staining area rate) was calculated by using image analysis software (Image J; National Institutes of Health). In a preliminary experiment, disks before and after placement in the mouth were stained with the dental plaque-disclosing solution, allowing the threshold of analyzing staining to be determined. For the total microbial measurement, 2 types of resin specimens were prepared: disk and palatal appliances. These resin specimens were made with an acrylic resin (Acron No. 3; GC Corp). The disks were divided into 2 groups: a TiO2-coated group and an uncoated group. Disks were attached to the retainer in the same location as in the denture plaque staining test. Palatal resin appliances were fabricated by waxing the participant’s maxillary cast, investing, and polymerizing. Single-arm clasps made of 0.9-mm cobalt-chrome alloy (Fine cobalt clasp wire; Yamahachi Dental Mfg Co) were applied to left and right of maxillary last molars. The mucosal surfaces of the palatal resin appliances were divided into 2 sides of the median line (broken line), and the 2 sides were randomly allocated to the TiO2-coated and uncoated groups by block randomization method (Fig. 1C). Either the disk or palatal resin appliance was placed in the participant’s mouth. The participants were instructed to remove the resin specimen and immerse it in water while eating, brushing, and sleeping. This test was performed 4 times in each participant for the 2 types of resin specimens (disk and palatal appliance) and for 2 durations (3 and 7 days). The types and durations were selected at random by block randomization method, and the interval between each test was at least 2 weeks. After the placement period, microbes were sampled by rubbing 1 cm length in the center of the specimen using a sterilized swab with 3 back-and-forth strokes under a 0.196N load. The used swab was then inserted into the disposable cup with pure water. The total number of oral microbes in the cup was counted on the surface of the resin specimen by using a bacterial counter (DUAA01NP-H; Panasonic Healthcare). The device was developed by applying the dielectrophoretic impedance measurement method, consisting of dielectrophoresis Obata et al

-

2017

3

Figure 1. Experimental resin specimens and retainer. A, B, Retainer prepared by pressing 1-mm-thick polyethylene terephthalate to participant’s maxillary cast. C, Palatal resin appliance.

*

Staining Area Rate (%)

100

n=10 *P<.05

90

Table 1. Mean ±SD rate of staining area, number of total microbes, VAS values, and adhesive force for uncoated and TiO2-coated dentures Uncoated

80

Parameter

70

Rate of staining area (%)

60

Total microbes (log10[CFU/mL])

TiO2-coated ±SD

P

81.5

0.1

17.1

10.9

<.001

Surface of buccal disks 3-day placement

5.8

0.1

5.3

0.1

.005

Surface of buccal disks 7-day placement

6.5

0.1

5.7

0.3

.005

30

Mucosal surface of palatal plate 3-day placement

6.6

0.2

5.5

0.3

.005

20

Mucosal surface of palatal plate 7-day placement

7.3

0.3

6.5

0.4

.005

17.8

30.8

79.8

32.9

.008

Dry

18.8

8.7

5.1

4.9

.005

Glycerin

17.2

7.1

3.7

2.9

.005

Water

14.3

4.9

3.8

2.3

.005

50 40

10 0

VAS value (mm)

Uncoated

Group

TiO2-coated

Figure 2. Comparison of rates of staining areas between uncoated group and TiO2-coated group. *Indicates significant differences (Wilcoxon signed rank test).

and impedance measurement.12 Measurements of the bacterial counter ranged from 1.00×105 to 1.00×108 colony-forming units (CFU)/mL. The surfaces of the resin disks were observed using scanning electron microscopy (SU6600; Hitachi). In total, 6 types of disks were observed: polished using abrasive paper (before primer coating), coated with the primer (before TiO2 coating; without placing in the mouth), TiO2-coated before placing in the mouth, TiO2-coated after placing in the mouth for 3 days, uncoated (polished until buffing) before placing in the mouth, and uncoated after placing in the mouth for 3 days. The chewing gum adherence test results were evaluated subjectively and objectively. Subjective evaluation was performed using the visual analog scale (VAS).13 The palatal appliance was prepared using the same method as described for the total microbial measurement. The palatal appliance was divided into 2 groups: TiO2-coated and uncoated groups. After the experimenter had inserted the palatal appliance, the participant was instructed to chew 3 g of chewing gum (Lotte Xylitol gum Lime Mint; Lotte Co Ltd) for 5 minutes and to answer the question: “Did the gum adhere to the palatal appliance?” The participant Obata et al

Mean ±SD Mean

Adhesive force (N)

VAS, visual analog scale.

then evaluated the feeling of adhesion of the gum to the palatal appliance, using a 100-mm VAS. “Very much so” as the worst condition was set at the left and “not at all” as the best condition was set at the right. The participant was instructed to mark their subjective evaluation on each scale. The distance between the left end and the mark was measured, and the distance measured was set as the VAS value. Objective evaluation was performed by the chewing gum adhesion test.14 Resin specimens (2×2×2 cm) were prepared using acrylic resin (Acron No. 3; GC Corp). The resin specimens were divided into 2 groups: the TiO2coated group and the uncoated group. A pair of resin specimens was attached to the upper and lower parts of a pulling device (MV-100; Imada Co Ltd) with a digital force gauge (DSN2-50N; Imada Co Ltd). After a volunteer had chewed 3 g of chewing gum (Lotte Xylitol gum Lime Mint; Lotte Co, Ltd) for 5 minutes, saliva on the chewing gum was removed with a wipe (Kimwipe; Kimberly Clark Corp). The gum was then placed between the upper and lower resin specimens and compressed until the distance between the resin specimens had narrowed to 1 mm. The upper resin specimen was then pulled at a crosshead speed of 100 mm/minute, and THE JOURNAL OF PROSTHETIC DENTISTRY

n=10 *P<.05

8

*

6

5

4

Uncoated

Total Microbes [log10(CFU/mL)]

Group

n=10 *P<.05 *

7

6

5

4

Uncoated

Group

C

-

6

5

Uncoated

Group

8

TiO2-coated

B n=10 *P<.05

*

7

6

5

4

TiO2-coated

Issue

*

7

A

8

-

n=10 *P<.05

8

4

TiO2-coated

Total Microbes [log10(CFU/mL)]

7

Total Microbes [log10(CFU/mL)]

Volume

Total Microbes [log10(CFU/mL)]

4

Uncoated

Group

TiO2-coated

D

Figure 3. Comparison of total number of microbes between uncoated group and TiO2-coated group. A, Buccal disks after 3 days. B, Buccal disks after 7 days. C, Total number of microbes on mucosal surface of palatal appliance after 3 days. D, Total number of microbes on mucosal surface of palatal appliance after 7 days. *Indicates significant differences (Wilcoxon signed rank test).  Outlier. Horizontal line that forms top of box is 75th percentile. Horizontal line that forms bottom of box is 25th percentile. Horizontal line that intersects box is median. Horizontal lines above and below box, called whiskers, represent maximum and minimum values.

the maximum force (N) during pulling was measured as the adhesive force. The measurement was performed 7 times in each group under 3 different conditions: when the surfaces of the resin specimens were dry, wetted with artificial saliva (40 mL of 60% glycerin solution in water), and wetted with distilled water (40 mL). The staining rates, the total number of microbes, and the VAS values were compared between the TiO2-coated and uncoated groups, using the Wilcoxon signed rank test, and the adhesive forces of the TiO2-coated and uncoated groups were compared using a Student t test (a=.05). All analyses were performed using statistical software (IBM SPSS Statistics v22.0; IBM Corp). RESULTS Figure 2 shows the results of the rate of staining. Significant differences were observed between the TiO2coated group and the uncoated group (P<.001) (Table 1). THE JOURNAL OF PROSTHETIC DENTISTRY

Figure 3 shows the results of the total microbial measurement test. All data under all conditions were within the measurement range of the bacterial counter. Significant differences were observed between the TiO2coated and the uncoated groups after 3 days and 7 days of placement in disk type and palatal type resin specimens (P=.005) (Table 1). Figure 4 shows scanning electron microscopy images of 6 disk surfaces. The disk polished with waterproof abrasive paper (up to #1000 grit) had grooves caused by abrasion (Fig. 4A). On the primer-coated disk (Fig. 4B) and the TiO2-coated disk (Fig. 4C), grooves caused by abrasion were not observed. On the TiO2-coated disk after placement in the mouth for 3 days, adhesion of microbes on the surface was less notable, and biofilm formation was inhibited (Fig. 4D). The disk polished until buffing (uncoated disk) before placement in the mouth (Fig. 4E) had shallow grooves compared with the disk polished with waterproof abrasive paper (up to Obata et al

-

2017

5

Figure 4. Surface observations of specimens by scanning electron microscopy (original magnification ×6000). A, Surface before primer coating. Polished using water-proof abrasive paper (up to #1000). Arrows point to grooves caused by abrasion. B, Surface after primer coating. C, Surface after TiO2 coating. D, Surface of TiO2-coated group after placement in mouth for 3 days. E, Surface of uncoated group polished until buffing. Arrows point to grooves caused by abrasion. F, Surface of uncoated group after placement in mouth for 3 days. Arrows point to microbes.

#1000 grit). In uncoated disks after placement in the mouth for 3 days, microbes and biofilm were observed (Fig. 4F). Figure 5 shows the results of the chewing gum adherence tests. On the subjective and objective tests results, significant differences were observed between the TiO2-coated and the uncoated groups under all conditions (P=.008 on the subjective test, P=.005 on the objective test under all conditions) (Table 1). DISCUSSION According to results of this study, the null hypothesis was rejected. Kado et al4 reported that TiO2 coating makes the resin surface rougher and more hydrophilic, a tendency similar to that found in the wettability of the present study. Kado et al4 reported that the water contact angle was 68.1 ±3.4 degrees in resin surfaces. However, TiO2 coating makes the resin surface more hydrophilic, with a water contact angle of 7.2 ±0.4 degrees. According to the results of this study, the total number of microbes decreased despite the increased surface roughness of resin specimens in the TiO2-coated group. Arai et al5 reported that TiO2 coating applied to denture base acrylic resin inhibited the adhesion of S sanguinis and C albicans organisms. These findings were also supported by the results obtained in this study. TiO2 coating improved the hydrophilicity of the surface of denture base acrylic resin and increased hydrophilicity inhibited

Obata et al

the adhesion of hydrophobic microbes such as S sanguinis. S sanguinis is an early colonizer in denture plaque formation,15 thus, suppressing the subsequent adhesion of other microbes and reducing the total number of microbes adhering to denture base resin. Mixed infections of endogenous anaerobic bacteria in the oral cavity are the main cause of aspiration pneumonia,16 inadequate cleaning of the denture increases the number of microorganisms in saliva,17 and denture plaque is a factor in microbial proliferation in the pharynx.18 The microbial measurement test showed that the total number of microbes adhering to the denture base resin can be reduced by TiO2 coating, which may contribute to the prevention of aspiration pneumonia. The 3 conditions used in the objective chewing gum adherence test for resin simulated xerostomia, healthy state, and water intake. The results of the subjective test also suggested that TiO2 coating inhibited the adhesion of gum to resin in the mouth. TiO2 coating of dentures inhibits the adhesion not only of plaque but also adhesive foods. This would benefit not only people requiring nursing care but all denture wearers. The participants in this study were younger than the population of denture wearers. According to the study by Toida et al,19 the prevalence of reduced stimulated salivary flow rate is higher in the elderly than in younger individuals. Therefore, the younger participants tested will affect the number of microbes on the surface of resin

THE JOURNAL OF PROSTHETIC DENTISTRY

6

Volume

*

Visual Analog Scale (mm)

100

n=10 *P<.05

90 80

Issue

-

microbes, denture plaque, and adhesive food in the mouth. 2. Further study is indicated to develop a TiO2 coating on acrylic resin for use in clinical practice.

70 60

REFERENCES

50 40 30 20 10 0

Uncoated

TiO2-coated

A

Group

*

30

Adhesive Force (N)

-

* *

n=7 *P<.05

20

10

0

Dry

Glycerin

Water

Group Uncoated

TiO2-coated

B

Figure 5. A, Comparison of participants’ feelings of food adhesion during chewing gum adhesion test scored by visual analog scale between uncoated group and TiO2-coated group. +Extreme value;  outlier. Horizontal line that forms top of box is 75th percentile. Horizontal line that forms bottom of box is 25th percentile. Horizontal line that intersects box is median. Horizontal lines above and below box, called whiskers, represent maximum and minimum values. B, Comparison of adhesive force in chewing gum adhesion test between uncoated group and TiO2-coated group. Surfaces of resin specimens were dry (Dry), wetted with artificial saliva (40 mL of 60% glycerin solution in water) (Glycerin), and wetted with distilled water (40 mL) (Water). *Indicates significant difference (Student t test).

compared with an older group. This is a limitation of this study and an evaluation with older denture wearers is required. CONCLUSIONS Within the limitations of this clinical study, the following conclusions were drawn: 1. TiO2 coating of denture base acrylic resin applied by the spray method inhibited the adhesion of

THE JOURNAL OF PROSTHETIC DENTISTRY

1. Nikawa H, Hamada T, Yamamoto T. Denture plaquedpast and recent concerns. J Dent 1998;26:299-304. 2. Pietrokovski J, Azuelos J, Tau S, Mostavoy R. Oral findings in elderly nursing home residents in selected countries: oral hygiene conditions and plaque accumulation on denture surfaces. J Prosthet Dent 1995;73: 136-41. 3. De Visschere LM, Grooten L, Theuniers G, Vanobbergen JN. Oral hygiene of elderly people in long-term care institutionsea cross-sectional study. Gerodontology 2006;23:195-204. 4. Kado D, Sakurai K, Sugiyama T, Ueda T. Evaluation of cleanability of a titanium dioxide (TiO2)-coated acrylic resin denture base. Prosthodontic Research and Practice 2005;4:69-76. 5. Arai T, Ueda T, Sugiyama T, Sakurai K. Inhibiting microbial adhesion to denture base acrylic resin by titanium dioxide coating. J Oral Rehabil 2009;36: 902-8. 6. Amano D, Ueda T, Sugiyama T, Takemoto S, Oda Y, Sakurai K. Improved brushing durability of titanium dioxide coating on polymethylmethacrylate substrate by prior treatment with acryloxypropyl trimethoxysilane-based agent for denture application. Dent Mater J 2010;29:97-103. 7. Mori K, Tsuji M, Ueda T, Sakurai K. Color and gloss evaluation of titanium dioxide coating for acrylic resin denture base. J Prosthodont Res 2015;59: 249-53. 8. Sawada T, Sawada T, Kumasaka T, Hamada N, Shibata T, Nonami T, et al. Self-cleaning effects of acrylic resin containing fluoridated apatite-coated titanium dioxide. Gerodontology 2014;31:68-75. 9. Shibata T, Hamada N, Kimoto K, Sawada T, Sawada T, Kumada H, et al. Antifungal effect of acrylic resin containing apatite-coated TiO2 photocatalyst. Dent Mater J 2007;26:437-44. 10. Cheng Y, Sakai T, Moroi R, Nakagawa M, Sakai H, Ogata T, et al. Selfcleaning ability of a photocatalyst-containing denture base material. Dent Mater J 2008;27:179-86. 11. Tsuji M, Ueda T, Sawaki K, Kawaguchi M, Sakurai K. Biocompatibility of a titanium dioxide-coating method for denture base acrylic resin. Gerodontology 2016;33:539-44. 12. Kikutani T, Tamura F, Takahashi Y, Konishi K, Hamada R. A novel rapid oral bacteria detection apparatus for effective oral care to prevent pneumonia. Gerodontology 2012;29:e560-5. 13. Wada T, Takano T, Ueda T, Sakurai K. Evaluation of participants’ perception and taste thresholds with a zirconia palatal plate. J Prosthodont Res 2016;60: 294-300. 14. Wada T, Takano T, Ueda T, Sakurai K. Comparison of adhesive resistance to chewing gum among denture base acrylic resin, cobalt-chromium alloy and zirconia. Bull Tokyo Dent Coll 2016;57:1-5. 15. Morris IJ, Wage WJ, Aldred MJ, Walker DM. The early bacterial colonization of acrylic palates in man. J Oral Rehabil 1987;14:13-21. 16. Okuda K, Kimizuka R, Abe S, Kato T, Ishihara K. Involvement of periodontopathic anaerobes in aspiration pneumonia. J Periodontal 2005;76(suppl 11):2154-60. 17. Ryu M, Ueda T, Saito T, Yasui M, Ishihara K, Sakurai K. Oral environmental factors affecting number of microbes in saliva of complete denture wearers. J Oral Rehabil 2010;37:194-201. 18. Sumi Y, Kagami H, Ohtsuka Y, Kakinoki Y, Haruguchi Y, Miyamoto H. High correlation between the bacterial species in denture plaque and pharyngeal microflora. Gerodontology 2003;20:84-7. 19. Toida M, Nanya Y, Takeda-Kawaguchi T, Baba S, Iida K, Kato K, et al. Oral complaints and stimulated salivary flow rate in 1188 adults. J Oral Pathol Med 2010;39:407-19.

Corresponding author: Dr Takayuki Ueda Department of Removable Prosthodontics and Gerodontology Tokyo Dental College 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-0061 JAPAN Email: [email protected] Copyright © 2017 by the Editorial Council for The Journal of Prosthetic Dentistry.

Obata et al

One Piece – Đảo Hải Tặc | - 72% Hoverboard (Bluetooth) mit Samsung Akku Zoll 8 rot-schwarz | Descargar APK