PURPOSE: The aim of this study was to evaluate the effect of polishing and glazing on the color and spectral distribution of monolithic zirconia. MATERIALS AND METHODS: Forty-five monolithic zirconia specimens (16.3 mm x 16.4 mm x 2.0 mm) were fabricated and divided into 5 groups according to the number of A2-coloring liquid applications (Group I to V). Each group was divided into 3 subgroups according to the method of surface treatments (n=3): N: no treatment; P: polishing; G: glazing. Color and spectral distribution of five different areas of each specimen were measured according to CIELAB color space in the reflectance mode relative to the standard illuminant D65 on a reflection spectrophotometer. Data were analyzed using one-way ANOVA followed by Tukey's HSD test, Pearson correlation and regression analysis (alpha=.05). RESULTS: There was a significant difference in CIE L* between Subgroup N and P, and in CIE b* between Subgroup P and G in each group. Spectral reflectance generally decreased in Subgroup P and G in comparison with Subgroup N. Color differences between Subgroup P and G were within the perceptibility threshold (DeltaE*ab< 3.7) in most groups. Highly significant correlation was found between CIE b*and each subgroups as the number of coloring liquid applications increased (R2>0.88, P<.001). CONCLUSION: A perceptible color difference can be detected after polishing of monolithic zirconia. Polishing decreases the lightness, and glazing also decreases the lightness, but increases the yellowness of monolithic zirconia.
Dental Polishing ; Light ; Surface Properties ; Zirconium

OBJECTIVETo evaluate the effects of different polishing methods on surface roughness of pure titanium castings.

METHODS35 pure titanium castings were devided into 7 groups, used for control, mechanic polishing and electrolytic polishing, respectively. Surface roughness (Ra value) of each castings was measured with a profilometer. Surface microstructure was studied by a scaning electron microscopy, and the weight loss (Wt%) and height loss on unit area (H) before and after polishing was calculated.

RESULTSThe effects of mechanic polishing with aluminium oxide or chromium oxide were acceptable. Surface smoothness was improved with acid treatment followed by electrolytic polishing.

CONCLUSIONAluminium oxide and chromium oxide can be used in mechanic polishing of pure titanium castings, and improvement should be made on electrolytic polishing methods.

OBJECTIVETo compare the surface roughness of nanofilled dental composite resin and microhybrid composite resins after curing and polishing.

METHODSA nanofilled composite (Z350) and 4 microhybrid composites (P60, Z250, Spectrum, and AP-X) were fabricated from the lateral to the medial layers to prepare 8 mm×8 mm×5 mm cubical specimens. The 4 lateral surfaces of each specimens were polished with abrasive disks (Super-Snap). Profilometer was used to test the mean surface roughness (Ra) after polishing.

RESULTSP60 had the lowest Ra (0.125∓0.030 µm) followed by Z250 and Spectrum. The Ra of Z350 (0.205∓0.052 µm) was greater than that of the other 3 resins, and AP-X had the roughest surfaces. Under scanning electron microscope, the polished faces of P60 resin were characterized by minor, evenly distributed particles with fewer scratches; the polished faces of Z350 presented with scratches where defects of the filling material could be seen.

CONCLUSIONThe nanofilled composite Z350 has smooth surface after polishing by abrasive disks, but its smoothness remains inferior to that of other micro-hybrid composite resins.

OBJECTIVETo compare the influence of polishing and glazing on ceramic surface roughness and bacterial adhesion to the resulted surfaces.

METHODSThe surface of the ceramic plates were tested and analyzed by atomic force microscope. The influence of resulted surface on Streptococcus mutans adhesion were also evaluated.

RESULTSThe ceramic surface became much smoother after polishing with diamond paste or self-glazing. A positive correlation between surface roughness and bacterial adhesion were observed. Compared with surfaces polished with rubber-wheel, surfaces polished with diamond paste or self-glazing reduced bacterial adhesion to the surface (P<0.05).

CONCLUSIONPolishing with diamond paste could be an alternative to self-glazing on ceramic surface roughness and bacterial adhesion.

OBJECTIVEThis study compared the roughness of porcelain polished or glazed surfaces and the adhesion of oral streptococcus mutans to them in vitro.

METHODS30 porcelain samples were made. Porcelain samples in group A were polished with diamond paste. Porcelain samples were glazed in group B and were polished with Al2O3 (240#) bur in group C. Their roughness values were measured by profilometer. Standardized cell suspensions were incubated with test samples for one hour at 37 degrees C, then retained cells were counted by image analysis (percentage area of a microscopic field covered by cells).

RESULTSRoughness values of group A, B, C were respectively (0.1987 +/- 0.057) microm, (0.1990 +/- 0.091) microm, (0.4260 +/- 0.174) microm. There was no significantly difference between group A and group B. The roughness samples in group C were significantly rougher than that in the other groups. The amount of retained cells in group A, group B, group C was respectively (15.92 +/- 4.37)%, (16.39 +/- 6.31)% and (41.48 +/- 12.1)%. There was no significant difference between the cell adhesion on porcelain surface glazed and polished, but more bacteria adhered on the porcelain surface in group C.

CONCLUSIONSPorcelain surface polished treatment was clinically acceptable compared with its glazed. They all exhibited the least amount of bacteria adhesion. The more porcelain surface was rough, the more bacteria adhered on it.

OBJECTIVETo evaluate the effect of thermal cycling on surface microstructure of different light-curing composite resins.

METHODSA nanofilled composite (Z350) and 4 microhybrid composites (P60, Z250, Spectrum, and AP-X) were fabricated from lateral to center to form cubic specimens. The lateral surfaces were abrased and polished before water storage and 40 000 thermal cycles (5/55 degrees celsius;). The mean surface roughness (Ra) were measured and compared before and after thermal cycling, and the changes of microstructure were observed under scanning electron microscope (SEM).

RESULTSSignificant decreases of Ra were observed in the composites, especially in Spectrum (from 0.164±0.024 µm to 0.140±0.017 µm, P<0.001) and Z250 (from 0.169±0.035 µm to 0.144±0.033 µm, P<0.001), whose Ra approximated that of P60 (0.121±0.028 µm) with smoothly polished surface. SEM revealed scratches and shallower pits on the surface of all the 5 resins, and fissures occurred on Z350 following the thermal cycling.

CONCLUSIONWater storage and thermal cycling may produce polishing effect on composite resins and cause fissures on nanofilled composite resins.

The purpose of the present study was to examine dental hygienists' perception of the current national practical examination. This research was performed using 199 self-reported surveys answered by professors of dental hygiene studies and clinical dental hygienist. Frequency analysis, chi-square tests, and analysis of variance were performed by using IBM SPSS Statistics ver. 20.0. The results revealed that many of the respondents consider the current national practical examination to be neutral. They did not think that the current national practical examination questions are useful for assessing occupation-centric integrated clinical practice ability and counseling techniques for patient intervention. The professors of dental hygiene studies believed that among the research tasks required as mentioned in the national practical examination questions, dental polishing and tooth brushing education are of paramount importance, whereas clinical dental hygienists believed that ultrasonic scaling is the most important (p<0.05). Most of the professors of dental hygiene studies reported that they conducted skills education for dental polishing and tooth brushing education, while most of the clinical dental hygienists reported that tasks actually performed in the clinic included impression taking, model fabrication, ultrasonic scaling, and explaining treatment precautions (p<0.05). Therefore, these tasks can be effectively carried out with the improvement of the national dental hygienist practical examination.
Counseling ; Dental Hygienists ; Dental Polishing ; Education ; Humans ; Oral Hygiene ; Surveys and Questionnaires ; Tooth ; Ultrasonics

PURPOSE: Surface finishing of a zirconia restoration is essential after clinical adjustment. Herein, we investigated the effects of a surface finishing protocol for monolithic zirconia on final roughness and bacterial adherence. MATERIALS AND METHODS: Forty-eight disk-shaped monolithic zirconia specimens were fabricated and divided into four groups (n = 12) based on initial surface treatment, finishing, and polishing protocols: diamond bur+polishing bur (DP group), diamond bur+stone grinding bur+polishing bur (DSP group), no diamond bur+polishing bur (NP group), and no diamond bur+stone grinding bur+polishing bur (NSP group). Initial and final surface roughness was measured with a profilometer, and shown using scanning electron microscope. Bacterial adhesion was evaluated by quantifying Streptococcus mutans in the biofilm. Kruskal-Wallis and Mann-Whitney U tests were used to compare results among groups, and two-way analysis of variance was used to evaluate the effects of grinding burs on final roughness (α=.05). RESULTS: The DP group had the highest final Ra value, followed by the DSP, NP, and NSP groups. Use of the stone grinding bur as a coarse-finishing step significantly decreased final Ra values when a diamond bur was used (P < .001). Omission of the stone grinding bur increased biofilm formation on specimen surfaces. Combining a stone grinding bur with silicone polishing burs produced the smallest final biofilm values, regardless of the use of a diamond bur in initial surface treatment. CONCLUSION: Coarse finishing of monolithic zirconia with a stone grinding bur significantly decreased final Ra values and bacterial biofilm formation when surfaces had been roughened by a diamond bur.
Bacterial Adhesion ; Biofilms ; Dental Instruments ; Dental Polishing ; Diamond ; Silicon ; Silicones ; Streptococcus mutans

PURPOSE: The purpose of this study was to evaluate the transmission of candida in denture by dental polishing lathe. MATERIALS AND METHODS: Maxillary complete dentures made from the same model were infected with Candida albicans. Polishing wheels were keep in various chlorhexidine solution and distilled water for an hour. The infected dentures were polished by prepared dental polishing lathe with sterile pumice and distilled water. And then sterile maxillary complete dentures were polished with same method. Polishing surface was wiped with a cotton swab and the sample was regrown for checking Candida albicans. RESULTS: All polishing wheel with chlorhexidine resist fungal infection. But the polishing wheel with distilled water is infected with Candida albicans. CONCLUSION: A chlorhexidine is highly efficient in fungal infection prevention on dental polishing lathe.
Candida albicans* ; Candida* ; Chlorhexidine* ; Dental Polishing* ; Denture, Complete ; Dentures ; Methods ; Water

OBJECTIVES: The aim of this in vitro study was to test the effect of 2 finishing–polishing sequences (QB, combining a 12/15-fluted finishing bur and an EVO-Light polisher; QWB, adding a 30-fluted polishing bur after the 12/15-fluted finishing bur used in the QB sequence) on 5 nanotech-based resin composites (Filtek Z500, Ceram X Mono, Ceram X Duo, Tetric Evoceram, and Tetric Evoceram Bulk Fill) by comparing their final surface roughness and hardness values to those of a Mylar strip control group (MS). MATERIALS AND METHODS: Twelve specimens of each nanocomposite were prepared in Teflon moulds. The surface of each resin composite was finished with QB (5 samples), QWB (5 samples), or MS (2 samples), and then evaluated (60 samples). Roughness was analysed with an optical profilometer, microhardness was tested with a Vickers indenter, and the surfaces were examined by optical and scanning electron microscopy. Data were analysed using the Kruskal-Wallis test (p < 0.05) followed by the Dunn test. RESULTS: For the hardness and roughness of nanocomposite resin, the QWB sequence was significantly more effective than QB (p < 0.05). The Filtek Z500 showed significantly harder surfaces regardless of the finishing–polishing sequence (p < 0.05). CONCLUSIONS: QWB yielded the best values of surface roughness and hardness. The hardness and roughness of the 5 nanocomposites presented less significant differences when QWB was used.
Composite Resins ; Dental Polishing ; Hardness ; In Vitro Techniques ; Microscopy, Electron, Scanning ; Nanocomposites ; Polytetrafluoroethylene