3666

Nano-hydroxyapatite Toothpaste With Hydrolyzed Conchiolin
Increases Tooth Enamel Gloss
R.TAKAMATSU, T.FUJIMARU, K.FUJITA and R.HAYMANSANGI Co., Ltd.Tokyo, Japan

Objectives
Hydrolyzed conchiolin (HC), derived from proteins promoting biomineralization in shells, is used in cosmetics and shampoos for moisturization, repair andgloss improvement. We tested its ability in toothpaste, in combination with nano-hydroxyapatite (nHAP), to increase enamel gloss.

Materials and Methods
1. Preparation of Tooth Specimens
Specimens were prepared from sound extracted human teeth without previous restorative treatment, caries or white-spot lesions, and cleaned using typicaldentifrice. After removing the root, the crown was sliced parallel to the tooth axis with a diamond disc. For gloss measurement, test teeth were fixed toacrylic cells with quick self-curing resin (UNIFAST Ⅱ, GC) and analyzed by surface gloss analyzer (SGA, 806H, TRICOR Systems Inc.).
2. Adjustment of Gloss
Since initial analysis showed variations in gloss, baseline adjustment of gloss was necessary. Test teeth were treated with a 300-times diluted phosphoricacid etchant (Clearfil, Kuraray-Noritake Dental) for 30 seconds and after washing with distilled water and drying with an air blow, the enamel surface gloss
was remeasured. This process was repeated until all test teeth had an adjusted gloss value of approximately 70.
3. Brushing Test
3-1. Test Dentifrices
Test dentifrices of different nHAP concentration were used: control pastes A, B, C, without HC(nHAP content ratio A: B: C = 1: 1.4: 2, n=8), and experimental pastes A+, B+, C+, containing
HC (Promois PEARL-P, Seiwa Kasei) (nHAP concentration as for controls, n=8). The pastes
were adjusted with water to slurry concentration (25g / 40ml) as a test solution.

3-2. Brushing and Gloss Measurement
The brushing machine used was composed of a constant temperature shaking incubator fittedwith a brush portion and a slurry bath containing the test teeth. To limit the effect to only the testsolution, the bristle portion of the toothbrush was eliminated, and replaced by felt. The test teeth
were fixed in the slurry bath and slurry poured in to soak the test teeth. They were then brushed
9min/day for 6 days (load 100g, amplitude 2cm, speed 100 rpm/min). After each daily brushing,teeth were washed with distilled water, dried with an air blow, and their surface gloss measured,
after which they were stored in 100% humidity at 37℃. The difference between the obtained
value and adjusted gloss value (⊿G) for each tooth was calculated, and the difference in daily ⊿G values between experimental and control groups compared. Statistical analysis was performed
using Student’s t-test.

Fig 1. Surface Gloss Analysis (SGA) SystemFig 2. Brushing Machine

4. Surface Analysis
A test for the presence of HC in the enamel surface after brushing was also carried out. Teeth were analysed by time-of-flight secondary ion mass
spectrometer (TOF-SIMS, ULVAC-PHI) at the Tokyo Metropolitan Industrial Technology Research Institute (Analytical conditions: Ga ion as the primaryion, output voltage 15kV, analysis area 100×100μm, detected positive secondary ion). Four samples were analysed : one tooth each brushed in group A
dentifrice (paste A or paste A+) for 6 days, HC alone, dropped onto an aluminum plate, and a sample of sound tooth enamel. Before analysis, all samples
were dried.

Results
1. Brushing Test and Gloss Measurement
・Gloss increased from the first day of brushing in both groups.
・Throughout the 6-day test, ⊿G for the experimental groups was greater than that of the control groups, and after 6 days, ⊿G for all experimental groups
was significantly higher than for controls (P <0.05).
・The value of ⊿G increased with the concentration of nHAP, suggesting a synergistic effect of both HC and the nHAP concentration.

(Group B)(Group C)

140140120120120100100100808080A+6040012345620001

Brushing days

2345C

40200C+

60

B

40200B+

60

A⊿G140⊿G⊿G(Group A)

60123456

Brushing days

Brushing days

Fig 3. Difference in daily ⊿G values between experimental and control groups

*160

*

140

*

*120
⊿G

100
80
60
40200AA+

B

B+C

C+(* P<0.05)

Test dentifrices

Fig 4. Difference in ⊿G values between experimental and control groups after 6 days

2. Surface Analysis
・In the resulting positive ion mass spectrum, some peaks derived from amino acid were detected in the HC sample, but only a main peak derived fromcalcium was detected in the A+, A and sound enamel samples.
・Results indicated that the enamel surface after brushing with HC toothpastes did not contain any HC.

(HC)

1.2
1.0

1.0

derived from amino acidderived from calcium

0.8

C/C0

*C/C
0

0.8
0.6

0.6

0.4

0.4

0.2

0.2

0.0

(A+)

1.2

0

10

2030

40

50

60

70

80

90

0.0

100

0102030

40

Mass (m/z)

50

60

70

80

(A)

(sound enamel)

1.2

1.0

1.0
derived from calcium

derived from calcium

0.8

0.8

C/C0C/C0100

Mass (m/z)

1.2

0.6

0.6

0.4

0.4

0.2

0.2

0.0

900102030405060

7080

90

100

0.0010Mass (m/z)

2030

405060

7080

90100

Mass (m/z)* C: counts, C0: max of counts

Fig 5. Positive ion mass spectrum of four samples

Conclusion
HC, in conjunction with nHAP, promotes increased enamel gloss. As no HC was detected in the enamel after surface analysis, we postulated that rather thanacting directly on the enamel surface, HC may support the deposition of mineral on and into the enamel by nHAP.
93rd General Session & Exhibition of the IADR/ March, 2015

E-mail : takamatsu@sangi-j.co.jp