A New Enamel Restoring Agent for Use after PMTC

1920
1．Aim of study

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M.NISHIO ,H.KAWAMATA ,K.FUJITA ,T.ISHIZAKI ,R.HAYMAN ,and T.IKEMI
12SANGI Co.,Ltd.Tokyo,Japan, Nihon University School of Dentistry at Matsudo,Chiba,Japan2

4．Results

3．Observation of Enamel surface smoothness and S.mutans Adherence

In recent years, PMTC (Professional mechanical tooth cleaning), used in preventive
dentistry to remove plaque, has proved effective in reducing caries and periodontal
disease and improving self-care sufficiency. However PMTC can cause abrasion of the
tooth surface and early return of plaque, and fine polishing to remove scratches is
considered helpful in reducing further plaque formation.
We developed a new, synthetic hydroxyapatite (HAP)-containing agent designed torestore tooth enamel, and studied its ability to (1) restore smoothness to the enamel and(2) inhibit adherence to the enamel of S.mutans following PMTC.

4-1. SEM Observation

PRTC-SF Treatment

PMTC Treatment
PMTC Treatment

・The enamel surface of PMTC-treated specimens was rougher than that ofcontrols, and increased in roughness according to the abrasive used (RDA
120＜170＜250 ).
・The enamel surface of Post-PMTC-treated specimens, i.e. those treated with
PRTC-SF, was smoother than that of PMTC-treated specimens in each case,and close in appearance to that of controls.

PRTC-SF Treatment

4-2. SPM Observation

500.0

500.0

2．Materials and Methods
0.0(nm)0mean of surface
roughness(Ra) 26.374nm

2-1. Preparation of tooth specimens

49777.54

0.0(nm)0mean of surface
roughness(Ra) 14.540nm

maximum height ofthe profile(Rmax) 391.23nm

RDA25035

9.568nm

49777.54
maximum height ofthe profile(Rmax) 169.47nm

500.00.00.0(nm)mean of surface
roughness(Ra)500.0(nm)00.0049777.54
maximum height ofthe profile(Rmax) 336.23nm

mean of surface
roughness(Ra) 19.775nm

Mean of surface roughness : Ra (nm)500.0

★to RDA120, p＜0.05★★to RDA120, p＜0.01★★★to RDA170, p＜0.05* p<0.01(nm)49777.54
maximum height ofmean of surface
the profile(Rmax) 193.29nm
roughness(Ra) 12.540nm

30* p<0.01★★
★★★

25RDA170

Control
Control

RDA1704-3. Adherence of S.mutans to enamel surface

1510RDA170- PRTC-SF0

RDA170-PRTC-SF

PMTC group

PRTC-SF group

Fig.3 Mean surface roughness (Ra) of tooth enamel surface
after PMTC treatment at different RDA, and of the same
following Post-PMTC treatment with PRTC-SF
Fig.5 Adherence of S.mutans to tooth enamel after PMTC
treatment at diferent RDA, and of the same following
Post-PMTC treatment with PRTC-SF.

0*Professional "Re-Enamel" Tooth Cleaning
R(nm)49777.54
maximum height ofmean of surface
the profile(Rmax) 333.96nm
roughness(Ra) 15.223nm

0.00(nm)mean of surface
roughness(Ra) 10.813nm

5．Discussion

maximum height ofthe profile(Rmax) 192.14nm

RDA120-PRTC-SF

Fig.2 SPM Observation of enamel surface
after each treatment

Fig.1 SEM Observation of enamel surface
after each treatment

2-5. Scanning probe microscope (SPM) observation
Three groups of control, PMTC-treated and Post-PMTC treated specimens (n=12)
respectively were observed by SPM (SPI4000, Seiko Instruments). (Observation
conditions: scanning area 50×50μm, dynamic force mode.) Statistical analysis wasperformed using Student's t-test.

Adherence of S.mutans (the number of cells / mm2 )1.0×106

Control

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RDA120-PRTC-SF

RDA120
RDA120・Adherence of S.mutans to PMTC-treated specimens was greater than incontrols, and increased according to the abrasive used in preparing thespecimens (RDA120＜170＜250 ). The difference was statisticallysignificant, except between the RDA 170 and 250 groups.
・Adherence of S.mutans to Post-PMTC treated specimens, i.e. those treatedwith PRTC-SF, was significantly lower than for PMTC-treated specimens,
and was observed by SEM to be equivalent to the level seen in controls.

500.0

500.00.0

・Mean surface roughness of PMTC-treated specimens was greater than that ofcontrols, and showed a significant increase according to the abrasive used
(RDA120＜170＜250 ).
・In contrast, mean surface roughness of Post-PMTC-treated specimens, i.e.
those treated with PRTC-SF, was significantly less than that of PMTC-treatedspecimens in each group, and was closer in both Ra value and surface
corrugation profile to that of controls.

★

205R

2-6. S.mutans adherence
S.mutans was grown in Brain Heart Infusion broth, by aerobic incubation at 37℃ for 18hours. Organisms were harvested by centrifugation, washed twice in phosphate bufferedsaline solution (PBS), and a bacterial suspension prepared by adjusting theirconcentration by absorbance photospectometry (UV-1200, Shimazu, O.D.550=0.3),
followed by sonication. Three groups of control, PMTC-treated and Post-PMTC treatedspecimens (n=6) respectively were cut to a size of 5×5mm and incubated in theS.mutans suspension at 37℃ for 24 hours. After incubation, specimens were washedtwice in PBS, fixed in 5%-glutaraldehyde and 4%-formaldehyde, and washed in a 0.1Mphosphate buffer for SEM observation as described in 2-4. Average bacterial adhesion
per group was calculated from a total count taken from 3 SEM frames per group atmagnification ×1,500, and the results statistically analyzed using Student's t-test.

RDA120
RDA170
RDA250* p<0.012-3. Post-PMTC (PRTC-SF) treatment
A group of PMTC-treated specimens was then polished in the same manner as for
PMTC in 2-2, using a newly developed synthetic HAP-containing agent,
PRTC Super Fine *(PRTC-SF, Sangi) as paste.
2-4. Scanning electron microscope (SEM) observation
Three groups of control, PMTC-treated and Post-PMTC treated specimens respectively
were dehydrated in ethanol, subjected to t-butylalcohol replacement, freeze-dried,
sputter-coated with Pt-Pd and observed by SEM (S-4500, Hitachi).
(Observation condition: vacc 5kV, emission 10μA, WD 5〜8mm, ×1,500)

RDA250- PRTC-SF

RDA250-PRTC-SF

02-2. PMTC treatment
Three groups of pretreated specimens each were subjected to 20 seconds PMTC with
polishing pastes of differing abrasiveness (RDA 250, 170 and 120 respectively)(Prophy paste, CCS Clean Chemical, Sweden A.B., fluoride-containing), using a dental
hand engine (viva-mate3, Nakanishi Inc.) with contra-angle (Adagio, W&H) and rubbercup (Prophy Cup #1800, Young Dental) attached.

maximum height ofthe profile(Rmax) 228.81nm

40

RDA250Specimens were prepared from sound extracted human anterior teeth. The enamel was
sliced at a depth of approximately 200〜300 μm from the labial surface with adiamond disc and pretreated by successive fine polishing under running water with 600
and 1200 grit abrasive paper (Buehler Microcut Discs) to achieve a standard surface
roughness of Ra=approx 10nm, as measured by scanning probe microscope (SPM,SPI4000, Seiko Instruments Inc.). A portion of the pretreated specimens were set asidefor use as standard controls.

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PMTC・Our results showed that mean surface roughness of post-PMTC enamel wasreduced by treatment with PRTC-SF, which contains synthetic HAP.
We postulated that the surface enamel was restored by the synthetic-HAP,
which is almost the same substance as tooth enamel.

RDA120
RDA170
RDA250★ to RDA120 p＜0.05★★ to RDA120 p＜0.01

5.0×105*p<0.01* p<0.01* p<0.01★★

1.0×105★

We concluded that PRTC Super Fine is an effective agent for restoring toothenamel to a smooth surface following PMTC, thereby reducing the adherenceof S.mutans to the post-PMTC enamel surface, and playing a useful role inprevention of caries.

1.05×105
9.41×104

6.78×104

5.0×104

2.61×104

PRTC-SF
1.11×104 1.15×104

0PMTC group

Fig.4 SEM Observation of adherence of S.mutans to enamel surface
after each treatment

・Treatment of post-PMTC enamel with PRTC-SF also reduced the adherenceof S.mutans to the enamel. We postulated that this was because treatment
with PRTC-SF restored the enamel to a smoother surface than that observed
after PMTC.

PRTC-SF group

Fig.5 Adherence of S.mutans to tooth enamel after PMTC
treatment at different RDA, and of the same following
Post-PMTC treatment with PRTC-SF

82nd General Session & Exhibition of the IADR / MARCH, 2004
nishio@sangi-j.co.jp