The authors wish to thank all of the participants, dentists, and assistants for their participation in this study. We sincerely thank Professor Hirotaka Kuwata and Assistant Professor Hirobumi Morisaki, Department of Oral Microbiology and Immunology, Showa University School of Dentistry, for their support.

1. Preparation of PMBPAz Solution (Figure 1)
<ol>
	<li>Synthesize MPC following a previously reported industrial procedure15.</li>
	<li>Synthesize the photoreactive MPC polymer PMBPAz using conventional radical polymerization of MPC, BMA, and MPAz in ethanol, as previously described14. 
	NOTE: PMBPAz should contain 60%, 30%, and 10% (mol %) of the aforementioned monomer units, respectively. Refrigerate the PMBPAz dissolved in ethanol to prepare a 0.5 wt% solution before use.</li>
	<li>Before ...

<ol>
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Prosthet. Dent. 112 (2), 194-203 (2014).</li></ol>

We have no disclosures or financial support.

Mechanism of the PMBPAz Coating
It is challenging to bind MPC polymers to a PMMA surface in a simple and stable manner. Here, we used a new photoreactive monomer bearing a phenylazide group, MPAz, which polymerizes with other monomers through a conventional free-radical polymerization procedure, resulting in a polymer with phenylazide side chains. The phenylazide groups are decomposed by UV irradiation to form nitrene groups, which are highly reactive radical groups that can covalently bind to al...

Oral healthcare plays an important role in the prevention of opportunistic infections and aspiration pneumonia in the physically vulnerable elderly. Oral healthcare, consisting of brushing after each meal, cleaning dentures, and receiving professional oral health care, plays a vital role in reducing the incidence of such diseases1-3. In particular, poor oral hygiene is strongly associated with aspiration pneumonia in the physically vulnerable elderly. Therefore, more attention should be paid to the oral health care of elderly patients, who have limited ability to clean their dentures by themselves4.
Even in developed countries, the use of acrylic, resin-based removable dentures remains the most common treatment option for edentulous elderly patients5. Given their high water absorption capacity, microporous surface, and hydrophobic nature, acrylic denture bases constructed from polymethyl methacrylate (PMMA) easily accumulate dental plaque on their surfaces, which is called denture plaque.
2-Methacryloyloxyethyl phosphorylcholine (MPC) polymers are well-known biomedical polymeric materials6 that have remarkable antithrombogenicity and tissue compatibility because of their high resistance to protein adsorption and cell adhesion7-11. MPC polymer coatings have been applied in various medical devices to prevent infection12 and have been suggested to have the potential to prevent denture plaque accumulation on PMMA denture surfaces13. The challenge in the clinical application of MPC polymers to PMMA dentures is to reliably bind them to PMMA surfaces in a simple and stable manner. Previously, MPC polymers were reported to be stably bound to PMMA surfaces by a grafting technique and to have the potential to inhibit plaque accumulation. However, the grafting technique is not simple and requires specialized equipment, which makes its clinical application challenging. Here, we describe a new MPC coating procedure that utilizes photoreactive phospholipid polymers-specifically, a photoreactive methacrylate derivative, 2-methacryloyloxyethyl-4-azidobenzoate (MPAz)-synthesized to accomplish a variety of surface modifications of different types of materials. MPAz was co-polymerized with MPC polymers and n-butyl methacrylate (BMA) to yield poly (MPC-co-BMA-co-MPAz) (PMBPAz). PMBPAz can covalently bind to the surfaces of PMMA dentures via activation of the azide groups in MPAz under ultraviolet (UV) light irradiation14. The procedure does not require any specialized equipment and can be completed by clinicians within 2 min. We also applied this procedure in a clinical setting and demonstrated its clinical utility and efficacy in inhibiting plaque deposition on removable dentures.

<table border="0" cellpadding="0" cellspacing="0" width="695">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:236px;">Ultrasonic Cleaner</td>
			<td style="width:104px;">Aiwa Medical Engineering</td>
			<td style="width:116px;">AU-12C</td>
			<td style="width:239px;">Clean in distilled water before stain the denture</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">UVP UV Crosslinker DL-1000</td>
			<td>Funakoshi</td>
			<td>95-0174-03</td>
			<td>UV light irradiation for 2min before use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Lightbox S</td>
			<td>Suntec</td>
			<td align="right">6542</td>
			<td>capturing in this box after stain the denture</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Adobe Photoshop CS6 Extended</td>
			<td>Adobe</td>
			<td></td>
			<td>Calucurate and quantify</td>
		</tr>
	</tbody>
</table>

2-methacryloyloxyethyl phosphorylcholine polymer treatment of complete dentures to inhibit denture plaque deposition

Removable dentures made of poly (methyl methacrylate) (PMMA) are prone to bacterial adherence and dental plaque formation, which is called denture plaque. Denture plaque-associated infection is a source of serious dental and medical complications in the elderly. 2-Methacryloyloxyethyl phosphorylcholine (MPC) is a well-known biomedical material that exhibits marked antithrombogenicity and tissue compatibility because of its high resistance to protein adsorption and cell adhesion. Therefore, MPC polymer coatings are suggested to have the potential to inhibit plaque deposition on the surface of PMMA dentures. However, coating MPC polymer on the surface of a PMMA denture is a complex procedure that requires specialized equipment, which is regarded as a major barrier to its clinical application. 
Here, we introduce a new MPC polymer treatment procedure that uses poly (MPC-co-BMA-co-MPAz) (PMBPAz) to prevent denture plaque deposition on removable dentures. This procedure enables the MPC coating of PMMA denture surfaces in a simple and stable manner that is resistant to various chemical and mechanical stresses due to the MPC layer of PMBPAz that is covalently bound to the PMMA surface by ultraviolet light irradiation. In addition, the procedure does not require any specialized equipment and can be completed by clinicians within 2 min. We applied this procedure in a clinical setting and demonstrated its clinical utility and efficacy in inhibiting plaque deposition on removable dentures.

PMBPAz treatment enables the MPC coating of PMMA surfaces through a simple and short method and maintains the plaque inhibition effect of the MPC polymer. This procedure does not require any specialized equipment and can be performed chair-side by clinicians within 2 min. Following protocol step 2, the PMBPAz treatment of removable complete dentures from 11 edentulous patients was successfully conducted in a clinical setting without any substantial problems. The mean percentage plaque ind...

Watch this Scientific Journal Video about 2-Methacryloyloxyethyl Phosphorylcholine Polymer Treatment of Complete Dentures to Inhibit Denture Plaque Deposition at JoVE.com

2-Methacryloyloxyethyl Phosphorylcholine Polymer Treatment of Complete Dentures to Inhibit Denture Plaque Deposition

Removable poly(methyl methacrylate) (PMMA) dentures are prone to bacterial adherence and plaque formation. Denture plaque-associated infection is a source of serious dental and medical complications in the elderly. This paper introduces a novel protocol to treat PMMA dentures with 2-methacryloyloxyethyl phosphorylcholine polymer, poly(MPC-co-BMA-co-MPAz), to suppress plaque deposition on PMMA dentures.

Removable dentures made of poly (methyl methacrylate) (PMMA) are prone to bacterial adherence and dental plaque formation, which is called denture plaque. ...

The overall goal of this experiment is to evaluate the effect of the new MPC polymer coating to prevent denture plaque deposition. This means that it can help answer key questions in the field of oral health care of the elderly population, such as how we can improve their denture hygiene. The main advantage of this technique is that dental clinicians do not have to prepare any specialized equipment, and it can be performed in a clinical office within two minutes.Implications of this technique, extend to the prevention of a variety of denture associated health problems, such as periodontal disease, denture stomatitis, and aspiration pneumonia. This method can provide insight into the simple and quick treatment of MPC polymer for complete dentures. It can also be applied to medical devices, for orthopedics.To begin the experiment, obtain the previously synthesized PMBPAz polymer. Synthesize the chilled photoreactive MPC polymer, PMBPAz, using conventional radical polymerization of MPC, BMA, and MPAz. Allow the PMBPAz ethanol solution to stand for 30 minutes at room temperature, before treating the PMMA surface.Using a denture brush, mechanically clean the denture for three minutes. Then, chemically clean the denture for five minutes in an ultrasonic bath sonicator, with a denture cleaner containing 2.0 percent sodium hypochloride. Before performing the surface modification with PMBPAz, wash the denture surface by immersion in ethanol.After the ethanol wash, allow the surface to air dry for one minute. Prepare one milliliter of 0.5 percent weight PMBPAz ethanol solution, from the previously prepared stock, and then let stand to allow the ethanol to evaporate. Next, with a brush applicator, apply the PMBPAz ethanol solution directly to the entire surface of the denture.Keep the denture at room temperature, and add atmospheric pressure for 10 minutes, to allow the solvent to evaporate in an ethanol vapor atmosphere. Irradiate the denture surface with UV light. Then immerse the PMBPAz-treated denture in distilled water for five minutes before use.Collect the denture that a patient has used for two weeks. Rinse the denture with tap water to remove any loose food particles, and then stain the denture with a 0.25 percent methylene blue disclosing solution for one minute in a polypropylene container. Clean any stains present on the denture surface in distilled water, using an ultrasonic bath sonicator.Next, prepare imaging to capture images at a 90 degree angle, on a wax seat, with a digital camera, with a white light system. Obtain images from three different directions to get mucosal, right, and left polished surface images. Then calculate the stained area, and quantify it using an image analysis software, for the entire denture surface.Select the denture area using the magnetic lasso tool, from the captured denture image. Next, change the red-colored channel to highlight the plaque area from the denture area image. Using the magic wand tool, and the select similar tool, select all plaque areas with a tolerance level of eight in the denture area.Count the total number of pixels for each image, then calculate the percentage plaque index of the area covered on the denture, from the pixel count of these images. Finally, evaluate the statistical differences between the stained areas on the PMBPAz-treated and untreated dentures. The total denture area of the mucosal surface after staining and digitization of both untreated, and the plaque area of the mucosal surface after selection, reveal that the stained plaque areas were consistently and markedly decreased by PMBPAz treatment.The mean percentages of the number of plaque pixels on the mucosal and polished surfaces of untreated and PMBPAz-treated dentures demonstrate that PMBPAz treatment of the mucosal and polished surfaces significantly inhibited the deposition of denture plaque. The development of this technique paved a new path for researchers to explore efficient and practical methods to prevent plaque-associated infections. Once mastered, this technique can be done in 30 minutes, if it is performed properly.After watching this video, you should have a good understanding of how to prevent opportunistic infections associated with denture plaque accumulation.

2-methacryloyloxyethyl-phosphorylcholine-polymer-treatment-complete

Research

JoVE Journal

Medicine

10.2K Views.  Showa University. The overall goal of this experiment is to evaluate the effect of the new MPC polymer coating to prevent denture plaque deposition. This means that it can help answer key questions in the field of oral health care of the elderly population, such as how we can improve their denture hygiene. The main advantage of this technique is that dental clinicians do not have to prepare any specialized equipment, and it can be performed in a clinical office within two minutes.Implications of this te...