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. 2009 Jun 19;4(6):e5986.
doi: 10.1371/journal.pone.0005986.

Mineralization potential of polarized dental enamel

Reina Tanaka  1 , Yo Shibata, Atsufumi Manabe, Takashi Miyazaki
Affiliations

Mineralization potential of polarized dental enamel

Reina Tanaka et al. PLoS One. .

Abstract

Background: Management of human teeth has moved from a surgical to a more conservative approach of inhibiting or preventing lesion progression. Increasing enamel mineralization is crucial in this regard. A potential difficulty is the preferential mineralization of the outermost portion of the enamel that can prevent overall mineralization. We describe a strategy for increasing the mineralization potential of dental enamel.

Methodology/principal findings: Extracted human premolar teeth enamel (n = 5) were exposed to a high concentration of hydrogen peroxide with an energizing source. Samples were stored in artificial saliva at 37 degrees C for 1 wk. A desktop X-ray micro-CT system was used to evaluate the mineral density of samples. Mineral distribution was polarized between the lower and the higher mineralized portion of enamel by charged oxygen free radicals due to activation of permeated hydrogen peroxide. The kinetics of energy absorption in the deeper enamel region demonstrated improvement of preferential mineralization into the region without restricting overall mineralization of the enamel. Subsequent increasing mineralization, even in the dense mineralized outer portion of enamel, was also achieved.

Conclusions/significance: This increased mineralization may promote resistance to acidic deterioration of the structure. The present study is one of the primary steps towards the development of novel application in reparative and restorative dentistry.

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Conflict of interest statement

Competing Interests: The present work is practically supported by the High Tech Research Center of the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT) (2008), and a Grant-in-Aid for the Encouragement of Young Scientists (B) from the Ministry of Education, Culture, Sports, Science and Technology of Japan. This work is also partially suppoted by Shofu Incorporated with a small grant.

Figures

Figure 1
Figure 1. Three-dimensional visualization of the ROI.
(a) Color gradation due to the different BMD range 2500–3200 mg/cm3 of hydroxyapatite of the untreated sample. (b, c) BMD range 2500–2600 mg/cm3 mineral within the ROI of the sample and after exposure to hydrogen peroxide with an energizing source. (d, e) Preferential mineralization of the deeper region (BMD range 2500–2600 mg/cm3) of treated enamel was generated after exposure to artificial saliva for 1 d. (f) Enhanced mineralization was seen in the outer portion (BMD range 2900–3200 mg/cm3) of the treated sample submerged in artificial saliva for 1 wk; 255-colour gradation of different BMD was assigned according to intensity.
Figure 2
Figure 2. Mineral volume versus BMD range as a function of time.
Mineral distribution of BMD range 2500–3200 mg/cm3 of hydroxyapatite within the ROI of (a) control and (b) treated sample. Mean values (n = 5) of mineral volume (mm3 of hydroxyapatite) between the range 2500 mg/cm3 and 3200 mg/cm3 of hydroxyapatite (2500–3200 mg/cm3 then 2600–3200 mg/cm3 up to 3100–3200 mg/cm3) within the ROI are shown.
Figure 3
Figure 3. Mean BMD within the ROI.
(a) Mean BMD (mg/cm3 of hydroxyapatite) within the ROI of control and (b) treated enamel. Results are mean±SD of each result (n = 5), and analyzed by analysis of variance (ANOVA) with a follow-up Tukey test.
See this image and copyright information in PMC

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