Tukey HSD Multiple Comparison Test Research Articles

Examination of Physical Activity Attitudes and Anti-Social Behaviors of Middle School Students

The aim of this study is to examine the physical activity attitudes and antisocial behaviors of middle school students. The research group of the study consisted of a total of 1046 students, 509 boys and 537 girls, aged between 11 and 13, studying in 5-6-7-8th grades in three secondary schools affiliated to the Ministry of National Education in Esenyurt district of Istanbul province in the 2022-2023 academic year. "Personal Information Form", "Physical Activity Attitude Scale for Secondary School Students" and "Antisocial Behavior Scale for Secondary School Students" were used as data collection tools. SPSS 25.0 statistical package program was used to evaluate the data and to find calculated values. Data were summarized by giving mean and standard deviations. Whether the data were normally distributed was checked with the range of Kurtosis and Skewness coefficients and it was determined that the data were normally distributed. Since the data were normally distributed, independent group t-test was used for pairwise cluster comparisons and One-Way Analysis of Variance (ANOVA) was used for more than two cluster comparisons. Tukey HSD multiple comparison test was used to determine the source of significant differences as a result of ANOVA. The Pearson Product Moment Correlation Coefficient was used to determine whether there was a significant relationship between the mean scores of the Physical Activity Attitude Scale and Antisocial Behavior Scale sub-dimensions of the participants who participated in the study. Within the scope of this study, the scale reliability coefficient was calculated as .77. The significance level was taken as 0.05. As a result of the analysis, no significant difference was found between the physical activity attitudes of secondary school students and family income level and mother's working status (p>0.05), while a significant difference was found between gender, grade level, mother's education level and father's education level variables (p<0.05). While no significant difference was observed between antisocial behaviors and family income level (p>0.05), a significant difference was found between other demographic variables (p<0.05). In addition, while no significant difference was found between the self-confidence sub-dimension of the Physical Activity Attitude Scale and the inappropriate behavior sub-dimension of the Antisocial Behavior Scale (p>0.01), significant differences were found between the other sub-dimensions (p<0.01) As a result, it can be said that students' physical activity attitudes affect antisocial behaviors.

Investigation of the Relationship between Character Structures and Mental Toughness of High School and University Students Doing Fencing Sports

The aim of the research is to examine the relationship between character structures and mental toughness of high school and university students doing fencing sports. Survey model, one of the quantitative research methods, has been used in the study. The sample of the research consisted of 286 active licensed fencing athletes who have competing in the classifications of the Turkish Fencing Federation and studying at high schools and university. As a data collection tool in the study Personal Information Form, Sport Character Scale (SCS) Sport Mental Toughness Questionnaire (SMTQ) has been used. In the data analysis, independent group t-test, one-way analysis of variance (ANOVA) test, Tukey HSD multiple comparison test, Pearson Product-Moment Correlation Coefficient test have been applied.
 As a result of the research; average of sports character scores of high school and university athletes; gender, age, education level, branch and nationality status variables have found to be significantly different. It has been specified that there wasn’t significant difference in the fencing experience period variable. Mental toughness score averages in sports; gender, age, education level, branch, fencing experience period, nationality status have found to be significantly different. It has been determined that there is a low and moderate positive and significant relationship in some sub-dimensions of the Sports Character Scale and Sport Mental Toughness Questionnaire.

Impact of environmental and soil factors in the prediction of soil carbon dioxide emissions under different tillage systems

Understanding the roles of natural drivers in greenhouse gas (GHG) emissions of arable fields is crucial for adequate agricultural management. This study investigated the combined effect of two tillage treatments (NT - no-tillage; CT - tillage with mouldboard ploughing) and environmental (air pressure, air temperature) and soil factors (total organic carbon, gravimetric water content and soil penetration resistance) on soil carbon dioxide (CO2) emissions in maize in 2020 and 2021. The soil tubes required for the laboratory measurement were derived from three different altitudes of the two differently cultivated fields from Fejér county, Hungary. The typical soil type was Chernozem in both fields. At the time of soil sampling, soil penetration resistance was measured with a 06.15SA Penetrologger in 10 repetitions. To preserve the moisture content of the soil columns during the investigation, moisture replenishment was performed equal to the degree of weekly theoretical evapotranspiration. Emissions measurements of soil columns were performed by close chamber technique for five weeks from sampling, 15 times, in 3 repetitions in laboratory conditions. The data were evaluated by two-way ANOVA, followed by the Tukey HSD multiple comparison test and two-tailed Student’s T-test at a significance level of p<0.05. The combined effect of environmental factors on soil carbon dioxide emissions was investigated using stepwise multiple linear regression. It has been proved that the observed difference between soil penetration resistance and soil carbon dioxide emissions was significant between CT and NT cultivation at different stages of the growing season. The analysis of the interaction of the experimental factors revealed that the combined effect of soil penetration resistance, total organic carbon and moisture content in tillage system (adjusted R2=0.92 at a significance level of p=0.05) in 2020, while the combined effect of moisture content and air temperature in the no-tillage system (adjusted R2=0.79 at a significance level of p=0.085) has the most significant effect on soil CO2 emissions in 2020. In 2021, the air temperature for the tillage system (adjusted R2=0.74 at a significance level of p=0.05) and the combined effect of air temperature and pressure for no-tillage systems (adjusted R2=0.69 at a significance level of p=0.1) played an important role in soil CO2 emissions. These observations highlight that different soil and environmental factors of different tillage significantly impact the soil carbon dioxide emissions in different years.

The efficiency of laser application for debonding laminate restorations manufactured of current CAD-CAM materials with different thicknesses.

Using lasers for adhesive restoration removal can be practical and atraumatic. The purpose of this study was to investigate Er: YAG laser exposure on debonding the adhesive cementation between enamel and feldspar ceramic, lithium disilicate-reinforced and resin nano ceramic composite laminate restorations. Vita Cerec Blocs, IPS e.max Computer-aided design (CAD). Computer-aided design and manufacturing (CAD-CAM) in full and Lava Ultimate restorative materials were chosen. The 3 × 3 mm2 standardized, 0.5-mm and 1 mm thick specimens were cemented on an enamel surface. After thermocycling, each material group was randomly divided into laser treated and control (non-laser treated) groups. Shear bond strength test was done with a universal testing machine with crosshead speed 0.5 mm/min. Factorial ANOVA Technique and TUKEY HSD multiple comparison test were used for statistical analyses. Moreover, the surface morphology of the debonded samples and the enamel was observed using a scanning electron microscope. The laser application was found to weaken the SBS values significantly (P < 0.05) for all groups; however, the most dramatic SBS decrease was observed for laser treated IPS e.max at both thicknesses. Laser treatment can serve as a practical and effective method that eliminates the risk the enamel damage and restoration fracture.

One-Way ANOVA, Tukey HSD, Scheffe, Bonferroni and Holm Multiple comparison tests for Physico-chemical Parameters in Four Water Bodies of Davangere District, Karnataka

Surface water samples were collected for physico-chemical analysis during 2016-17 from four water bodies (Hadadi lake, Gonivada lake, Lokikere lake and Shagalealla) of Davanagere district , Karnataka. The main objectives of this study is to analyse various parameters such as pH, EC, turbidity, total alkalinity, total dissolved solids, chloride, total hardness, calcium, sodium, sulphate ,nitrogen and potassium. One-way ANOVA, Tukey HSD test with Scheffe, Bonferroni and Holm multiple comparison for the water quality parameters were carried out. pH of all the four water bodies are alkaline in nature with the total hardness included under hard to very hard category. Most of the water quality parameters are highest in Shagalehalla due to the agricultural runoff from the surrounding areas and human anthropogenic activities. One Way ANOVA for physical parameters depicted “F statistic value of 52.1265 with a “P” value of 1.112. Similarly, for chemical parameters “F”value and “P” values are 29.3941 and 5.6732 respectively. The p-value consequent to the F-statistic of one-way ANOVA is lower than 0.05 level and Tukey's HSD test to each of the six pairs of water quality parameters them exhibits statistically significant difference, We Compared the outcome against drinking water quality standards as per WHO and BIS, and it is observed that water samples from these water bodies are potable for human consumption after proper treatment due to moderate levels of pollution as per the physico-chemical data. It is concluded that the physico-chemical characteristics of the water indicates that the water bodies are moderately eutrophic in nature and there is an urgent need of preventive measures.

Üniversite Adaylarının Spor Yaralanma Kaygı Düzeylerinin İncelenmesi

The aim of the study is to examine the sports injury anxiety of the candidates who applied to university with a special aptitude test in terms of demographic variables. Şanliurfa Harran University consists of 321 candidates, 209 male and 112 female, residing in different provinces and having different branches, who have applied to the school of physical education and sports. In this study, Sports Injury Anxiety Scale” and “Personal Information Form” were used as data collection tools; The scale has 6 sub-dimensions and consists of 19 items in total. In order to determine whether the sports injury anxiety differentiates according to the variables of the candidates, the independent sample t-test and the one-way analysis of variance result from the statistical difference between the groups; Tukey HSD multiple comparison test was conducted. According to the results obtained in the evaluation of the scale scores, in terms of the smoking variable, the Sports Injury Anxiety scale was statistically analyzed with the anxiety of losing ability, disappointing anxiety and anxiety of loss social support, Significant differences were determined (p <0.05). In terms of the age variable, statistically significant differences were found with the anxiety about loss of ability sub-dimension (p <0.05). In terms of gender variable, statistically significant differences were found with suffering anxiety, disappointing anxiety, anxiety of losing social Support (p <0.05). According to the results of multiple comparisons of the physical activity variable, statistically significant differences were found in the anxiety of losing social support and re-injury anxiety dimensions (p <0.05). When the scale is evaluated in terms of total score dimension, according to the results of the research, it shows that the average score of sports injury anxiety level is low for the candidates preparing for university. It is thought that this low anxiety level may be related to the motivation to prepare for the exam and desire to enter the university.

Bond Strength Evaluation of Bulk- fill Composites to Dentin Under Different Surface Treatments

Purpose: The aim of this study is to compare the shear bond strength of three high-viscosity bulk-fill composite resins applied as single layers of 4mm thickness and of one microhybrid composite resin applied incrementally with a thickness of 2mm on dentin surfaces prepared with different surface preparation methods. Materials and Methods: A total of 132 caries-free human molars whose dentines had been exposed were used. Three groups, each containing 44 teeth, were formed. The acid group was etched with 32% phosphoric acid; laser group was etched with Er, Cr; YSGG laser and the control group was prepared with silicon carbid paper. Following the application of bonding agent, composite resin materials were applied on teeth using teflon moulds of 4x4mm. The samples were then subjected to shear bond strength tests. Two-way variance analysis and Tukey HSD multiple comparison test were applied on collected data. Results: There was a significant difference between surface treatment methods used regarding shear bond strength (P&lt;0.001). The highest shear bond strength values were detected in the “Acid” group while the lowest shear bond strength values were detected in the “control” group. On the other hand, there was no statistically significant difference among composite resins (P&gt;0.05). Conclusions: Laser etching of the dentin tissues is not as effective as acid etching. Bulk-fill composites had similar effects compared with conventional composite resins with regard to bonding strength. More in vitro studies supported with clinical data are required to investigate the performance of bulk-fill composites and laser.

Coping Mechanisms Used by Women with Major Depression

The purpose of this study is to compare women with major depression against their matched healthy controlsabout their coping mechanisms and the severity of their symptom condition.Method: This cross-sectional hospital-based survey recruited 37 women with major depression and 40non-depressed women as healthy controls. Simple random sampling was used to select the participants.Data was collected by using self-reported tools. Descriptive statistics and interpretative analysis of data wasperformed by using independent-samples t-test, ANOVA, and post hoc Tukey HSD multiple comparisontests to find out the accurate differences between levels of depression.The results show that women who used more self-blame, rumination bordering on to brooding, and lesspositive reframing had higher levels of depressive symptoms. Among the positive coping mechanisms, itwas noted that in the clinical sample used instrumental and emotional supports. With regard to negativestrategies for coping depression, self-blame, self-distraction, denial and venting were common. The use ornon-use of a given coping mechanisms varied with the severity of depression.Conclusion: The study concludes that women with major depression use qualitatively different copingmechanisms for coping depression than healthy controls. This has implications for planning psychotherapeuticprograms for the affected women.

Evaluación de la resistencia a la tracción del acrílico después de la desinfección con agua ozonizada y microondas.

Background: There is a need for safe disinfection methods without a detrimental effect on the acrylic denture base. Aim: the purpose of the current study was to evaluate the effect of ozonated water and two protocols of microwave disinfection on tensile bond strength of high-impact acrylic. Material and methods: Eighty samples were divided into four major groups: one control and three experimental groups, 20 specimens each. The experimental groups each received either disinfection by ozonated water, microwave 850W/1min, or microwave 650W/6min. Further division of the major groups into two sub-groups depending on the number of disinfection cycles and total immersion time in distilled water: One cycle and one day versus seven cycles and seven days. The control group specimens were immersed in distilled water without any disinfection for either one day or seven days. Tensile strength testing was performed on the specimens from the eight groups. The data were analyzed by SPSS version 21#. The ANOVA and Tukey-HSD multiple comparison tests were used for comparison for groups. Results: A non-significant difference in the tensile strength was observed in the groups subjected to one cycle of ozone or microwave disinfection at 850W/1min. There was a significant decrease in tensile strength for the specimens subjected to one cycle of 650W/6min microwaving. The number of testing cycles and storage time in distilled water had a significant impact on the tensile strength of the acrylic in all tested groups, by decreasing it. Conclusion: Ozone disinfection and microwaving at 850W for one minute did not affect the tensile strength of the acrylic, but repeated disinfection over seven days at one cycle per day impaired the tensile strength of the acrylic resin.

Spor Bilimleri Fakültesi Öğrencilerinin Taraftarı Oldukları Futbol Takımına Karşı Psikolojik Bağlılıklarının İncelenmesi

Although the fans are one of the main sources that keep the clubs alive, it is extremely wrong to ignore this audience and not to conduct research based on scientific methods about them. It will be important for the clubs to understand this community that is attached blindly and does not stop supporting their team. In this study, the aim was to understand the psychological commitment of the Faculty of Sport Sciences students to the team they support and examine this commitment in terms of different variables. The study group of this research consisted of 446 students, 162 of whom were females and 284 were males, who continue their education at Mugla Sitki Kocman University the Faculty of Sport Sciences. As data collection tools; the Psychological Commitment to Team (PCT) Scale developed by Mahony et al. (2000) and adapted to Turkish by Eskiler et al. (2011) and the Personal Information Form prepared by the researchers to determine the demographic characteristics of the students were used. In the analysis of the obtained data; to determine the socio-demographic characteristics of the participants, frequency and percentage analysis, and to evaluate the psychological commitment of students to their teams according to different variables t-test and one-way analysis of variance (ANOVA) were applied. After one-way analysis of variance(ANOVA), Tukey HSD multiple comparison test was applied to determine from which groups the statistical difference occurred. In statistical analysis and interpretation of the data, p<0.05 significance level was taken into consideration. Taking gender into account, the results of the research showed that male students had higher TPB scores than female ones. In addition, according to the team variable, it was determined that the TPB scores of the students who were fans of Fenerbahce were significantly higher than the other team fans. According to another result, it was found that the TPB scores of the participants who said that I didn’t buy official products were significantly lower than other fans.

Evaluation of vitamin D levels and body mass indexes of university employees

Objective: Vitamin D is known to have important effects on human health. The existence of a relationship between obesity and vitamin D levels, which have been shown to cause a number of health problems with various studies, is certain. In this study, the relationship between vitamin D levels and body mass indexes(BMI) of individuals was evaluated. The study is unique for being the only research on literature that carried out with university employees.&#x0D; Materials and methods: Blood samples, anthropometric measurement (BMI) was obtained from 87 volunteer working at Haliç University. The questionnaire form covering the basic questions applied by means of face-to-face method. Quantification of the analytes for 25-hydroxyvitamin-D was carried out using LC-MS/MS. The relationship between 25-hydroxyvitamin-D values and BMI was evaluated with Tukey HSD multiple comparison test. 95% confidence and 80% power sampling were applied to the predictions of a minimum0.50 connection coefficient between 2 quantitative variables.The necessity of 30 cases was determined by using the N = [(Zα+Zβ)/C]2 + 3formula.Considering the losses, the work will be carried out over 80 people.&#x0D; Results and Discussion: There’s significant difference between 25-hydroxyvitamin-D2 and 25-hydroxyvitamin-D3 and the BMI levels of the subjects(p:0.028&lt;0.05-p:0.000&lt;0.05). The average 25-hydroxyvitamin-D3 and 25-hydroxyvitamin-D2 levels of overweight participants were significantly higher than the mean levels of underweight participants’. No significant relationship was found between 25-hydroxyvitamin-D3 and 25-hydroxyvitamin-D2 levels and the time spent outdoors during summer and winter.&#x0D; Conclusion: To prevent vitamin D deficiency and insufficiency is to obtain some sensible sun exposure, ingest foods that contain vitamin D, and take supplement.&#x0D; Bangladesh Journal of Medical Science Vol.19(2) 2020 p.229-236

Comparison of translucency and flexural strength of fiber-reinforced composite resin materials

Aim: The purpose of this study was to compare translucency values and flexural strength of composite resin materials reinforced with two different fibers.Materials and Methods: In this study, two direct composites (Clearfil Majesty Esthetic and Posterior) and an indirect composite (Tescera) used with a non-fiber control group and two fiber-reinforced (EverStick glass fiber and Ribbond polyethylene fiber) composite groups. Thirty specimens were obtained from the entire composites with dimensions of 25×2×2mm3. Translucency parameter values of the specimens were obtained using a spectrophotometer. The flexural strength (MPa) of the specimens was then determined by a three-point bending test at a rate of 1 mm/min until fracture occurred in the specimen using a universal tester. Data were analyzed by Two Way ANOVA and Tukey HSD multiple comparison test (α=0.05).Results: Ribbond group showed similar translucency parameter values with the control group in all composite materials, but the EverStick group showed significantly lower than the control group (p 0.001). The highest mean flexural strength values were seen in the Clearfil Majesty Posterior control group, while the lowest values were seen in the Clearfil Majesty Esthetic Ribbond group. The mean flexural strength values of the control groups for each composite were found statistically significantly higher than the fiber groups.Conclusion: The fiber addition to composite resins may affect the optical and mechanical properties of the restoration. This effect varies depending on the structural properties of composite resin and fiber. This situation should be taken into consideration in the restoration.

Assessment of the Brand Attitudes of Taekwondo Coaches and Referees

The objective of this study is to examine and interpret the brand attitudes of the coaches and referees who take part in contests actively in our country and were included in the 2017 season activity schedule of Turkish Taekwondo Federation and who attended the Coaches and Referees Improvement Seminar held in Antalya on December 11-19, 2017. The study group consists of 346 coaches and referees who took part in the mentioned improvement seminar in the 2017 season. In the study conducted on the basis of the survey model, Brand Attitude Questionnaire developed by Polat (2007) was used. In the evaluation of the data and in finding the calculated values, SPSS 16,0 statistics package program was used. Data were summarized by providing the percentages, averages, and standard deviations. As the data were distributed normally, an independent group t test was used for the double group comparisons and One-way Variance Analysis (ANOVA) was used for the multiple group comparisons. Upon the conclusion of the ANOVA study, Tukey HSD multiple comparison test was used to determine the source of the significant differences. In the scope of this study, the scale reliability coefficient was calculated as 0.89. In the study, the significance level was taken as 0.05 In conclusion of the study, and upon the scrutiny of the Brand Attitude Questionnaire point averages of the referees and coaches participating in the study as per the variables of gender, economic level, and sportive experience period, no statistically significant level of differentiation was observed in all the subcategories, while statistically significant differences were found in some subcategories according to the variables of age and marital status.

Shear bond strength of veneer composite to cobalt-chromium alloys fabricated differently

Objective: The purpose of this study was to assess and contrast the shear bond strength of a veneer composite resin bonded to cobalt-chromium (CoCr) dental alloys produced by different techniques. Material-Method: Ninety cylindrical specimens (10mm in diameter, 8mm in height) made of CoCr dental alloys were prepared by casting (C), milling (M), LaserCUSING with and without annealing (CL+, CL), and direct metal laser sintering (DMLS) with and without annealing (EL+, EL). Veneer composite cylinders (5mm in diameter, 3mm in height) were built on metal specimens using a silicone jig. After storage in water for 24 hours, the specimens were assessed for bond strength with a shear force test at a crosshead speed of 0.5 mm/min. The shear bond strengths (SBSs) were statistically analyzed using the Kolmogorow-Smirnow test and Tukey-HSD multiple comparison test (α=.05). Results: When the SBS values of the groups were compared, significant differences were found among the groups (P<.05). While statistically significant differences were found between the CL+ group (9.36 ∓ 2.62) and the M group (13.34 ∓ 2.53) (P<.05), there were no significant differences among the others (P>.05). The debonded surfaces of the specimens exhibited mostly mixed failure types. Conclusions: The CoCr alloy fabrication technique has an effect on the SBSs between the veneer composite resin and the metal used. LaserCUSING casting, a new technology, seems to have the lowest metal-resin bond strength among all the techniques tested.

Problem-solving skills of futsal players with regard to some socio-demographic variables

The aim of this study is to evaluate problem-solving skills of female futsal teams that compete in the Futsal League of Turkish Universities Sports Federation in terms of some socio-demographic variables. In total, 144 students from female futsal teams of 10 universities competing in the Futsal League of Turkish Universities Sports Federation voluntarily took part in this study. In the study, “Problem-Solving Inventory” that was developed by Heppner & Petersen was used. With this inventory, such sub-dimensions of the participants as “reliance on problem-solving skill”, “approach-avoidance” and “self-control” were analysed . In the statistical analysis of the obtained data during the research study, differences have been revealed by using one-way analysis of variance (One-Way ANOVA). And in the comparison of the averages of groups, Tukey HSD multiple comparison test was used. Research findings revealed that there are statistically significant differences between the points gained from the sub-dimensions of “reliance on problem-solving skill” and “approach-avoidance” with respect to the participants’ sporting age and the attended school; “reliance on problem-solving skill” with regard to father’s educational background; “approach-avoidance” with respect to income level (P<0.05). As a result, it is understood that such variables as sporting age, father’s educational background, income level and the attended university have important effects on individuals, and it is seen that individual’s level of solving problems increases as the sporting age increases. Within this scope, individuals are advised to start doing sports at early ages in order for them to develop their problem-solving skills.

Shear Bond Strength and ARI Score of Chemically Cured Orthodontic Adhesive Resins

The purpose of this study was to compare shear bond strength and to evaluate Adhesive Remnant Index (ARI) score among three chemically cured orthodontic adhesive resins, namely Unite (3M Unitek, USA), Rely-a-Bond (Reliance, USA) and Ortho-Force (China). Materials and methods: Ninety extracted human maxillary premolars were randomly divided into 3 groups (30 teeth/group). Upper premolar metal brackets (Ormco, USA) were boned by using the following adhesive systems: Unite, Rely-a-Bond and Ortho-Force. After 24 hours, shear bond strength was tested by using a Universal Testing Machine with a crosshead speed of 0.5 mm/min. After debonding, all teeth and brackets were examined under 10-times magnification and scored by using Image-Pro Plus 7.0 software program. Results: One-way ANOVA followed by post-hoc Tukey HSD multiple comparison test showed a statistically significant (P&lt;0.05) difference among groups. Ortho-Force had the lowest shear bond strength (17.53±3.60 MPa) and demonstrated statistically significant difference (P&lt;0.05) from the other groups. The difference between Unite (22.40±3.11 MPa) and Rely-a-Bond (20.67±2.70 MPa) was not statistically significant. The bond failure sites were categorized according to the ARI, and the Chi-square test showed significant differences in the ARI scores (P&lt;0.05) among all sample groups. The ARI score of 3 was found to be the most prevalent in Ortho-force (73.33%), followed by Unite (66.67%), and Rely-a-Bond (0%). In Rely-a-Bond group, ARI score of 1 was the most prevalent (66.67%). Only Unite had no residual adhesive left on tooth surface after debonding (6.67%). Conclusions: Unite and Rely-a-Bond produced greater shear bond strength than Ortho-Force. According to ARI score, Unite and Ortho-Force had a high frequency of all the adhesive remained on the tooth surface but Rely-a-Bond had high frequency of less than half the adhesive remained on the tooth surface.

Shear bond strength of ceramic fused to CAD-CAM milled alloys.

BackgroundThis study evaluated the metal ceramic bond strength of cast Ni-Cr, cast Co-Cr, sintered Co-Cr and milled Co-Cr alloys to ceramic through two application procedures including the ceramic layering technique and ceramic pressed-on technique.Material and MethodsCeramic materials (Ø 8 mm, 1.5 mm thickness) were veneered by either the layering or pressed-on technique to cast Ni-Cr, cast Co-Cr, sintered Co-Cr and hard milled Co-Cr alloy disc (12 × 12 × 0.5 mm) (n=15). All specimens were treated with a thermal cycle process for 500 cycles at the temperature between 5 °C and 55 °C with immerse time of 30 seconds and 5 seconds for specimen transfer. The shear bond strength was determined on a universal testing machine at a crosshead speed of 0.5 mm/min. The de-bonding surfaces were examined under visual inspection and SEM. The metal ceramic interface of specimens for each group was examined in SEM and EDS. The means of bond strength were compared using two-way ANOVA followed by post-hoc Tukey HSD multiple comparison test to determine for statistically significant difference at 95% level of confidence. The Weibull analysis was used for determination survival probability of shear bond strength.ResultsThe bond strength of ceramic to sintered Co-Cr alloys was higher than that to others metal alloys. The metal-ceramic mean bond strength was significantly higher for the ceramic pressed-on technique than that of the ceramic layering technique for all tested alloys (p<0.05). Weibull analysis of the shear bond strength indicated that the sintered Co-Cr alloys veneered with heat pressed ceramic provided the highest characteristic strength of metal ceramic bond.ConclusionsThe sintered Co-Cr alloys significantly contributed the appropriate bond strength for metal ceramic. Ceramic pressed-on was a reliable technique to enhance bond strength for fabrication the metal ceramic restoration. Key words:Bond strength, sintered alloy, milled alloy, Co-Cr alloys, metal ceramic.

The effect of repair protocols on shear bond strength to zirconia and veneering porcelain

The aim of this study was to evaluate the shear bond strength (SBS) of a new repairing material including zirconia primer to zirconia and veneering porcelain after various surface treatments. A total of 60 specimens (30 zirconia-Zr and 30 feldspathic porcelain-Feld) were prepared and divided into 6 groups (n = 10). Two surface preparations (air abrasion-AA and Erbium Yag (Er-YAG) Laser-Las) were applied to the specimens. Zr and Feld specimens treated with a grinding bur according to manufacturer advice, were used as control (C). Repair material (Cimara Zircon, VOCO, Germany) was applied to the specimens 2 mm in height. The SBS was measured in a universal testing machine at 1 mm/min crosshead speed. The SBS data (MPa) were analyzed using two-way ANOVA and Tukey HSD multiple comparison tests (α = 0.05). Significant effects of the material type (p = 0.005) and the surface treatment strategy (p = 0.000) were found. Interaction terms were also significant (p = 0.000). While the Zr-C (68,4 MPa) showed the highest SBS (p < 0.05), Zr-Las (16,4 MPa) had the lowest SBS (p < 0.05). The highest SBS value was obtained when both zirconia and veneering porcelain were treated with a grinding bur without any additional surface treatment.

Effects of whitening dentifrice on yttria-stabilized tetragonal zirconia polycrystal surfaces after simulating brushing

Statement of problemThe changes that occur after brushing yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) are unknown. These changes may favor the retention of microorganisms and chemisorption of water, impairing its longevity. ObjectiveThe purpose of this in vitro study was to evaluate the effects of a whitening dentifrice on Y-TZP surfaces after simulating 10 years of brushing. Material and methodsSeventy-two bar-shaped specimens (20×4×1.2 mm) were divided into 4 groups: storage in distilled water (SW, control), brushing with distilled water (BW), brushing with dentifrice (BD), and brushing with whitening dentifrice (BWD). Brushing was conducted using a linear brushing machine (878400 cycles, 0.98 N, soft toothbrush). The mean roughness (Ra) was analyzed with a profilometer and the superficial topography with scanning electron microscopy (SEM) at baseline and after treatment. Crystalline phases were characterized using x-ray diffraction. Baseline and posttreatment Ra were analyzed using the 1-way ANOVA and Tukey HSD multiple comparison test; the paired t test was used for intragroup comparison (all α=.05). ResultsThe Ra (μm) means (before/after treatment) were SW 0.28/0.28; BW 0.32/0.31; BD 0.28/0.36; BWD 0.30/0.20. No statistically significant difference was found for Ra at baseline (P=.108) than for posttreatment results (P<.001); the BD group had higher Ra values when compared with baseline (P=.019); the BWD group had the lowest values (P<.001). The BD surfaces showed pronounced scratches and detachment of the surface, while BWD showed smoother surfaces; similar crystallographic results among groups were observed. ConclusionsBrushing Y-TZP with conventional dentifrice increased roughness, while brushing with whitening dentifrice reduced roughness. Neither dentifrice changed the crystallographic phases after brushing.

Shear bond strength of veneering porcelain to zirconia: Effect of surface treatment by CNC-milling and composite layer deposition on zirconia

ObjectivesThe purpose of this study was to evaluate the shear bond strength of veneering feldspathic porcelain to zirconia substrates modified by CNC-milling process or by coating zirconia with a composite interlayer. MethodsFour types of zirconia–porcelain interface configurations were tested: RZ – porcelain bonded to rough zirconia substrate (n=16); PZ – porcelain bonded to zirconia substrate with surface holes (n=16); RZI – application of a composite interlayer between the veneering porcelain and the rough zirconia substrate (n=16); PZI – application of a composite interlayer between the porcelain and the zirconia substrate treated by CNC-milling (n=16). The composite interlayer was composed of zirconia particles reinforced porcelain (30%, vol%). The mechanical properties of the ceramic composite have been determined. The shear bond strength test was performed at 0.5mm/min using a universal testing machine. The interfaces of fractured and untested specimens were examined by FEG-SEM/EDS. Data was analyzed with Shapiro–Wilk test to test the assumption of normality. The one-way ANOVA followed by Tukey HSD multiple comparison test was used to compare shear bond strength results (α=0.05). ResultsThe shear bond strength of PZ (100±15MPa) and RZI (96±11MPa) specimens were higher than that recorded for RZ (control group) specimens (89±15MPa), although not significantly (p>0.05). The highest shear bond strength values were recorded for PZI specimens (138±19MPa), yielding a significant improvement of 55% relative to RZ specimens (p<0.05). SignificanceThis study shows that it is possible to highly enhance the zirconia–porcelain bond strength – even by ~55% – by combining surface holes in zirconia frameworks and the application of a proper ceramic composite interlayer.