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Universal Research Journal of Dentistry September-December 2014
Vol 4 Issue 3158
INTRODUCTION
Dental ceramic has been used in dentistry for over 150 years.[1]
Currently, dental ceramic is used extensively as a restorative
material in a variety of dental restorations, including allceramic
restorations, metal ceramic crowns, fixed partial dentures, and
even in complete dentures in some cases because of its aesthetic
properties, durability, and biocompatibility.[2]
It is a common clinical practice to adjust the glazed surface of
ceramic restorations before insertion by grinding.[3] Surface
modifications are essential for correcting occlusal interferences
and inadequate contours, finishing the margins of ceramic
restorations, and improving the
The Effects of Porcelain Finishing and Polishing Systems on the
Surface Roughness of Feldspathic Porcelain: An In Vitro Study
Manoj Shetty, Raghavendra Jaiman, Prasad D KrishnaDepartment of
Prosthodontics and Crown and Bridge, Attavar Balakrishna Shetty
Memorial Institute of Dental Sciences, Nitte University,
Mangalore, Karnataka, India
esthetic appearance and surface smoothness of ceramic
restorations.[4]
A rough surface may abrade the opposing tooth or restorative
materials. Abrasiveness is more correlated with ceramic
roughness[5] than with hardness.[6] Several studies have shown that
finished ceramic can produce equal or less enamel wear than glazed
ceramic.[7,8] The roughness of intraoral hard surfaces has a major
impact on the initial adhesion and retention of oral
microorganisms.
The current study deals with the efficiency of surface polishing
systems after the glaze layer of the ceramic has been altered using
a medium grit diamond to simulate the chairside adjustment of a
restoration. It is aimed to analyze the relative efficiency of each
of the four polishing systems by comparing them with roughened
samples, keeping glazed samples as control.
O R I G I N A L A R T I C L E
Introduction: This in vitro study deals with the efficiency of
surface polishing systems after the glaze layer of the ceramic has
been altered using a medium grit diamond to simulate the chairside
adjustment of a restoration. Materials and Methods: Forty porcelain
discs measuring 10 mm 3 mm with a metal substructure of 10 mm 1 mm
were used. Ceramco 3(ultralow fusing feldspathic porcelain)
porcelain system was used to fabricate the discs on the metal
substructure. A medium grit diamond was used to simulate the
chairside adjustment procedures. Ten samples were glazed (control
group) and 30 samples were finished and polished using three
finishing and polishing agents. (experimental group; Shofu
Ceramaster, Kohinoor diamond polishing paste and SofLex
discs).These 40 samples and the initial roughened samples were
subjected to a profilometer evaluation to obtain results in Ra
(Average roughness in m) and Rz (Mean maximum peak tovalley height
in m). Results: One way ANOVA revealed a statistical significant
difference amongst Ra values of the group. Amongst the finished and
polished group of samples, the samples polished with Shofu
Ceramaster diamondimpregnated silicon showed the highest efficiency
among the three finishing and polishing systems followed by samples
polished with Kohinoor L highly filled diamond polishing paste and
the least efficient polishing system was the samples polished using
SofLex discs. The Rz (Mean peaktovalley height) values showed the
same results as the Ra values. Conclusion: The study concluded that
among the three finishing and polishing systems tested, Shofu
Ceramaster diamond impregnated silicon rubbers are the most
efficient with significant differences in surface roughness
compared to roughened samples
KEY WORDS: Feldspathic porcelain, profilometry, surface
roughness
ABSTRACT
Access this article onlineQuick Response Code
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DOI:10.4103/2249-9725.140676
Address for Correspondence: Dr. Manoj Shetty,
Department of Prosthodontics and Crown and Bridge, A. B Shetty
Memorial Institute of Dental Sciences,
Nitte University, Deralakatte, Mangalore, Karnataka 575 018,
India.
Email: [email protected]
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Shetty, et al.: Effects of porcelain finishing and polishing
systems on surface roughness
159Universal Research Journal of Dentistry September-December
2014 Vol 4 Issue 3
MATERIALS AND METHODS
The porcelain discs consisted of metal substructures prepared by
casting metal discs of 10 1 mm size using Fornax casting machine by
Bego. Girobond CBS, a carbonfree NiCrMobonding alloy, was used for
casting the metal substructure for the required 40 discs. [Figures
1 and 2] The porcelain was then layered on all 40 metal
substructures using Ceramco3 (ultralow fusing feldspathic
porcelain) porcelain system. The buildup was done using purely
enamel crystals as the occlusal adjustment requires reduction of
enamel layer of the prosthesis. The final porcelain discs along
with the metal substructure measured 10 3 mm. All 40 discs were
glazed with overglaze followed by which a medium grit diamond
rotary instrument was used on all discs to emulate the chairside
occlusal adjustment of prosthesis [Figure 3]. Out of the 40
roughened porcelain discs, 10 discs were glazed with overglaze and
the remaining 30 discs were finished and polished using 3 finishing
and polishing systems and 1 system for a group of 10 discs.
The agents used for polishing the three groups of samples were
Group 1: Shofu Ceramaster: Diamondimpregnated silicone polishers
[Figure 4], Group 2: Reinfert Kohinoor: Highly filled diamond
particle polishing paste [Figure 5], Group 3: SofLex finishing and
polishing system [Figure 6].
Finally, all samples were tested for their surface roughness
using Surtronic 3+ surface roughness analyzer by Taylor Hobson Ltd.
(distance travelled by the stylus 2.5 mm) for parameters Ra and Rz
[Figures 7 and 8]. Each sample was analyzed three times. The values
were digitally displayed on the profilometer and then
tabulated.
Statistical analysisStatistical analysis was performed by a
oneway ANOVA (SPSS version 16.0) to compare the three finished and
polished group of samples (experimental
groups) and the glazed samples (control group) with the
roughened samples to find if there was any statistical significance
between the five groups. Also, a posthoc analysis using Tukey HSD
was performed to compare each of the three finished and polished
group of samples with the roughened and glazed group of samples and
with every other group.
RESULTS
The mean and standard deviation was calculated and tabulated for
a oneway ANOVA test of the samples [Table 1].
A oneway ANOVA revealed that a statistically significant
difference exists between the five groups. It compared the five
groups to reveal that the highest Ra and Rz values were obviously
seen for the roughened samples with a mean Ra of 5.23 m and mean Rz
of 26.31 m. Among the three finished and polished groups of
samples, the most efficient finishing and polishing system was
Shofu Ceramaster (Grp 1). Grp 1 samples had a mean Ra of 3.89 m and
mean Rz of 18.57 m. Second most efficient was Kohinoor L highly
filled diamond polishing paste (Grp 2). Grp 2 had a mean Ra of 4.66
m and mean Rz of 24.08 m. The least efficient amongst the three
groups was the SofLex finishing and polishing system (Grp 3). Grp 3
had a mean Ra of 4.83 m and mean Rz of 24.64 m. Finally, the glazed
group, which was the control group, revealed a mean Ra of 1.06 m
and a mean Rz of 3.43 m.
The posthoc analysis Tukey HSD was done to compare Ra (average
roughness) values of the roughened group of samples and the three
polished groups of samples (experimental groups) and glazed group
of samples (control group) [Table 2].
It was found that the Ra values of Grp 1 samples (mean Ra 3.89
m) and those of the roughened samples (mean Ra 5.23 m) showed a
statistically significant
Table 1: Oneway ANOVA test (Grp 1Shofu, Grp 2Kohinoor and Grp
3Soflex)Descriptive N Mean Std. Deviation Statistic df1 df2 Sig.Ra
(in microns)
Roughened samples 30 5.232667 1.197083 165.879 4 68.715
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Shetty, et al.: Effects of porcelain finishing and polishing
systems on surface roughness
Universal Research Journal of Dentistry September-December 2014
Vol 4 Issue 3160
difference (P < 0.05) whereas the Ra values of Grp 2 samples
(mean Ra 4.65 m) and the Grp 3 samples (mean Ra 4.82 m) did not
show a statistically significant difference (P > 0.05) when
compared to the roughened samples (mean Ra 5.23 m).
Furthermore, the Ra values of glazed samples (Control group)
(mean Ra 1.06 m) were compared to the Ra values of all three
polished groups of samples (experimental group) (mean Ra 3.89 m,
4.65 m, and 4.82 m) and it revealed a statistically significant
difference (P < 0.05).
Figure 7: Surtronic 3+ surface roughness analyzer by Taylor
Hobson Ltd. Figure 8: Measurement of surface roughness of a
sample
Figure 6: SofLex finishing and polishing system
Figure 5: Reinfert Kohinoor: Highly filled diamond particle
polishing paste
Figure 4: Shofu Ceramaster Diamondimpregnated silicone
polishers
Figure 3: Glaze surface removal using mediumgrit diamond
Figure 1: All samples (40 glazed samples)Figure 2: Thickness of
(a) Metal substructure; (b) Porcelain buildup
ba
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Shetty, et al.: Effects of porcelain finishing and polishing
systems on surface roughness
161Universal Research Journal of Dentistry September-December
2014 Vol 4 Issue 3
When Ra values of the various polished samples were compared to
each other, it was revealed that the Ra values of Grp 2 samples
(mean Ra 4.65 m) did not have a statistically significant
difference to the Ra values of Grp 1 samples (mean Ra 3.89 m) and
Grp 3 samples (mean Ra 4.82 m). Whereas the Ra values of the Grp 1
samples (mean Ra 3.89 m) had a statistically significant difference
compared to the Ra values of the Grp 3 samples (mean Ra 4.82
m).
The Rz (mean peaktovalley height) values showed the exact same
correlation as the Ra values except the Rz values of Grp 2 samples
(mean Ra 24.08 m) and Rz values of Grp 1 samples (mean Ra 18.57 m),
which showed a statistically significant difference unlike the Ra
values.
DISCUSSION
With the increased use of ceramic materials in dentistry, one
must pay careful attention to the efficacy of different polishing
systems and techniques, the brittle nature of this material and
whether the intraoral polishing techniques using rotary
instruments, such as diamond burs and rubber abrasives, can provide
a clinically acceptable smoothness due to the high hardness of
ceramic materials. It is a wellknown fact that post adjustment can
be overcome using overglaze or various finishing and polishing
systems available.
While some studies have verified that glazing resulted in a
smoother surface compared to polishing, other studies
have found comparable final surfaces for both finishing
methods.[911] There have also been studies that showed polished
ceramic surfaces to be smoother than glazed surfaces.[12,13]
The current study compares the efficacy of three such finishing
and polishing agents in polishing samples of feldspathic porcelain
after the glaze layer had been removed from them using a mediumgrit
diamond keeping the glazed samples as the control group. A
mediumgrit diamond was used so as to have a better idea about the
relative efficiency of each of the finishing and polishing systems.
This removal of the glazed layer simulated the rough surface of
porcelain following chairside adjustment of a restoration.
Following the use of medium grit diamond to simulate the
chairside adjustment procedures, 10 samples were glazed (Control
group) and 30 samples were finished and polished using three
finishing and polishing agents (experimental group; Shofu
Ceramaster, Kohinoor diamond polishing paste, and SofLex discs).
All these 40 samples and the initial roughened samples were
subjected to profilometer evaluation to obtain results in Ra
(average roughness in m) and Rz (mean maximum peaktovalley height
in m). The values from the profilometer evaluation were subjected
to statistical analysis. A oneway ANOVA revealed that a
statistically significant difference between the five groups. It
compared the five groups to reveal that the highest Ra and Rz
values were obviously seen for the roughened Samples with a mean Ra
of 5.23 m and mean Rz 26.31 m. Amongst the three finished and
polished
Table 2: Posthoc analysis tukey HSD (Grp 1Shofu, Grp 2Kohinoor,
and Grp 3Soflex)
Tukey HSDDependent variable (I) grp (J) grp Mean difference (IJ)
Std. error P valueRa (in microns)
Roughened samples Glazed samples 4.171333 0.283524
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Shetty, et al.: Effects of porcelain finishing and polishing
systems on surface roughness
Universal Research Journal of Dentistry September-December 2014
Vol 4 Issue 3162
group of samples. The most efficient finishing and polishing
system was Shofu Ceramaster. Shofu samples had a mean Ra 3.89 m and
mean Rz of 18.57 m. The second most efficient finishing and
polishing system was Kohinoor L highly filled diamond polishing
paste, which had a mean Ra of 4.66 m and mean Rz of 24.08 m. The
least efficient amongst the three groups was the SofLex finishing
and polishing system, which had a mean Ra of 4.83 m and mean Rz of
24.64 m. Finally, the glazed group, which was the control group
revealed a mean Ra of 1.06 m and a mean Rz of 3.43 m.
When Ra values of the various polished samples were compared to
each other, it revealed that the Ra values Kohinoor L (mean Ra 4.65
m) samples did not have a statistically significant difference to
the Ra values of Shofu samples (mean Ra 3.89 m) and SofLex samples
(mean Ra 4.82 m). Whereas the Ra values of the Shofu samples (mean
Ra 3.89 m) had a statistically significant difference compared to
the Ra values of the SofLex samples (mean Ra 4.82 m).
The Rz values showed the exact same correlation as the Ra values
except the Rz values of Kohinoor L samples (mean Ra 24.08 m) and Rz
values of Shofu samples (mean Ra 18.57 m), which showed a
statistically significant difference unlike the Ra values.
This finding is in agreement with previous reports on the effect
of different polishing techniques on the surface roughness of
several dental ceramics. In a study done on refinishing of
porcelain by using a refinishing kit, the effects of a group of
commercially available finishing kits on Vita VMKbonded porcelain
was investigated qualitatively and quantitatively using scanning
electron microscope and surface profilometer. The kit proved
incapable of restoring a surface glaze to porcelain adjusted using
a fine (red band) diamond bur.[14,15]
Another study that was done to assess the effects of porcelain
polishing techniques on color and surface texture of different
porcelain systems, and it concluded that chairside porcelain
polishing systems were not able to provide a porcelain surface as
smooth as the glazed surface for Ceramco 3 porcelains.[11]
CONCLUSION
Within the limitations of the study it was concluded that:
Among the three finishing and polishing systems tested, Shofu
Ceramaster diamondimpregnated silicon rubbers are the most
efficient, showing a statistically significant difference in
surface roughness compared to roughened samples.
However, none of the finishing and polishing systems were able
to provide a porcelain surface as smooth as the glaze group.
The Kohinoor L highly filled diamond paste and SofLex finishing
and polishing system did not show significant difference in surface
roughness compared to the roughened samples.
This study made use of a medium grit diamond in order to
simulate chairside adjustment since it provides for better
evaluation of relative efficiency of the three finishing and
polishing systems. However, clinically, a fine grit diamond or a
12fluted carbide bur diamond should be used for chairside
adjustment of porcelain restoration.
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How to cite this article: Shetty M, Jaiman R, Krishna PD. The
effects of porcelain finishing and polishing systems on the surface
roughness of feldspathic porcelain: An in vitro study. Univ Res J
Dent 2014;4:158-62.Source of Support: Nil, Conflict of Interest:
None declared
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