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pH and effects on Streptococcus mutans growth of denture adhesives: an in vitro study

Authors

  • Fengying Chen,

    1. Key Lab for Oral Biomedical Engineering of Ministry of Education, School of Stomatology, Wuhan University, Wuhan, China
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    • Fengying Chen and Tiantian Mao contributed equally to this article.
  • Tiantian Mao,

    1. Key Lab for Oral Biomedical Engineering of Ministry of Education, School of Stomatology, Wuhan University, Wuhan, China
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    • Fengying Chen and Tiantian Mao contributed equally to this article.
  • Xiangrong Cheng

    Corresponding author
    1. Department of Prosthodontics, School of Stomatology, Wuhan University, Wuhan, China
    • Correspondence to:

      Xiangrong Cheng, Department of Prosthodontics, School of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan 430079, China

      Tel.: +86 27 87646351

      Fax: +86 27 87873260

      E-mail: cheng_xiangrong@hotmail.com

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Abstract

Objectives

To evaluate the pH and effects on Streptococcus mutans growth of denture adhesives.

Background

There is little information regarding the pH of contemporary adhesives and their influences on S. mutans growth.

Materials and methods

The adhesives tested were Polident® cream, Protefix® cream and Protefix® powder. Samples of each adhesive were added to deionized water to produce solutions of 10.0, 5.0, 2.5 and 1.0% w/v (cream formulations) or 5.0, 2.5,1.0 and 0.5% (powder formulation). The pH values were measured immediately after preparation and at 1-, 2-, 3-, 6-, 12-, and 24-h intervals using a digital pH meter. Streptococcus mutans UA159 was inoculated in the Brain Heart Infusion medium with or without the adhesive extracts (control). Bacterial growth was observed by measuring absorption at 600 nm every 1 h for 12 h using a spectrophotometer.

Results

The tested adhesives generally remained relatively pH-stable over 24 h, ranging from 5.5 to 7.0. There were no statistically significant differences in S. mutans growth rates between the extract-treated and control cultures (p > 0.5).

Conclusions

Some adhesives produce a pH below the critical pH of hydroxyapatite and may not be suitable for patients with natural teeth. None of the tested adhesives significantly affect S. mutans growth.

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