Effects of different toothpastes on the color and whiteness of stained anterior composite resin.

PURPOSE: To evaluate changes in the color of an anterior nanohybrid composite resin and differences in its whitening index after 30 days of brushing with six brands of whitening toothpaste in vitro to simulate the situation in individuals with high coffee consumption. METHODS: Eighty-four disk-shaped resin specimens were prepared (shade A2). For initial staining, the samples were immersed in coffee solution for 14 days and then divided into eight groups for treatment with various toothpastes. Color was assessed at the baseline, after initial staining, and on days 7, 14, and 30 of the staining-and-brushing cycle. Color stability was evaluated based on the CIEDE2000 color difference (ΔE00), and differences in whiteness were determined using the whitening index for dentistry (WID). RESULTS: The highest ΔE00 and ΔWID values were obtained with Colgate Herbal, followed by Opalescence Whitening and Crest Baking Soda and Peroxide, whereas the lowest values were obtained with distilled water, followed by Yotuel Pharma B5, on day 30 of the staining-and-brushing cycle. CONCLUSION: In terms of improving the color and whiteness of coffee-stained anterior nanohybrid composite resin, Colgate Herbal, Opalescence Whitening, and Crest Baking Soda and Peroxide yielded promising results after 30 days of continuous use.

Effect of staining and bleaching on the microhardness, surface roughness and color of different composite resins.

BACKGROUND: There are studies that examined the effect of staining on the surface properties of composite resins, using different solutions and bleaching applications. However, the effect of both staining and bleaching on the same composite specimens is an issue that needs to be investigated. OBJECTIVES: The aim of this study was to investigate the surface microhardness, roughness and color changes (ΔE) of 2 different composite resins after staining and bleaching. MATERIAL AND METHODS: A microhybrid and a nanohybrid composite were used in the study. One hundred and fifty specimens were prepared from each composite. The specimens were divided into 5 groups and stained for 30 days with tea, coffee, cola, red wine, or distilled water (control). Subsequently, each group was divided into 3 subgroups. Each subgroup received a 14-day application of Opalescence™ Boost, Opalescence PF or VivaStyle® Paint On Plus bleaching materials. The color as well as surface microhardness and roughness of all specimens were determined at baseline, after staining and after bleaching. Data was analyzed using the repeated-measures analysis of variance (ANOVA) and the Bonferroni method. RESULTS: A statistically significant decrease was observed in the surface microhardness of the microhybrid composite specimens after bleaching (p < 0.05).The highest ΔE values were observed in the red wine groups for both composite resins. CONCLUSIONS: Staining and bleaching may affect surface properties and color, depending on the type, filler and matrix content of the composite resin.

Evaluation of saliva glutathione, glutathione peroxidase, and malondialdehyde levels in head-neck radiotherapy patients

Background/aim: It is believed that radiotherapy has important effects on oxidant/antioxidant systems. Oxidative stress occurs when the balance between oxidant formation and antioxidant defense is disrupted in favor of oxidants. The aim of this study was to determine the biochemical changes in saliva pre- and postradiotherapy in head-neck radiotherapy patients and to find out the effects of radiation on glutathione (GSH), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) levels in saliva. Materials and methods: This study included 16 patients undergoing head-neck radiotherapy in Atatürk University Research Hospital. The levels of GSH, GSH-Px, and MDA were measured in saliva samples taken from the patients pre- and postradiotherapy. The same biochemical parameters were also measured in saliva samples from 30 healthy individuals who did not undergo head-neck radiotherapy. The data obtained were analyzed using the paired t-test and the Mann­Whitney U test. Results: When the levels of GSH (P > 0.05), GSH-Px (P > 0.05), and MDA (P < 0.05) in saliva were compared pre- and postradiotherapy in the patient group, the only significant increase was detected in the MDA level postradiotherapy. When the pre- and postradiotherapy levels of saliva GSH (P < 0.01, P < 0.001, respectively), GSH-Px (P > 0.05, P < 0.05, respectively), and MDA (P < 0.01, P < 0.001, respectively) were compared with those of the control group, it was revealed that the GSH level was significantly lower and the MDA level was significantly higher in both pre- and postradiotherapy compared to the control group. Also, only the postradiotherapy saliva GSH-Px level was found to be significantly lower than the control group. Conclusion: These findings show that the changes in saliva GSH, GSH-Px, and MDA levels in patients with head-neck malignity intensified due to radiation.

A stereological study of the effects of mercury inhalation on the cerebellum.

Mercury in the environment that arises from organic and inorganic sources can cause irreversible damage to the nervous system. Toxicity may be direct or may arise from interactions with other metals in the environment. We evaluated the possible effects of mercury vapor on rat cerebellum. Twelve adult female rats were divided into control and experimental groups. The rats in the experimental group were exposed to mercury vapor for 9 h/day for 45 days. Cerebellar tissue samples were evaluated using stereology and for histopathology. The total number of Purkinje cells was estimated using a physical disector method. We found that in the experimental group, overall volume decreased and the number of Purkinje cells was reduced. We also found cellular damage including pycnotic nuclei, eosinophilic cytoplasm and vacuolization; these features were absent in the control group. We found that chronic exposure to inorganic mercury vapor is toxic to the cerebellum.

Anticariogenic potential of white cheese, xylitol chewing gum, and black tea.

OBJECTIVE: This study aimed to examine the effects of these foods on plaque pH and the potential development of tooth decay. MATERIALS AND METHODS: Plaque pH was measured using the sampling method before and after 1, 5, 10, 20, 30, 45, and 60 min following consumption of these foods individually and after rinsing with a 10% sucrose solution. Statistical analysis was performed using one-way ANOVA and Tukey honestly significant difference post hoc tests (α = 0.05). RESULTS: Although there were statistically significant differences in all test groups except the BT (P = 0.620) and sucrose + XCG (P = 0.550) groups in time, none of the participants chosen for this study were having a plaque pH value anywhere close to the critical value (pH = 5.5). CONCLUSION: WC, BT, and XCG are advisable as anticariogenic foods because pH values are not below critical value.

Comparison of radiopacity of different composite resins.

BACKGROUND: The radiopacity of composite resins has been considered as an important requirement, improving the radiographic diagnosis. AIM: The present study aimed to compare the radiopacity of eight different composite materials using an aluminum step wedge. MATERIALS AND METHODS: Eight different composite resins were used in this study. The samples were prepared using a stainless steel mold (2 × 8), and a 2-mm-thickness horizontal section was obtained from the freshly extracted molar tooth. Three different radiographs were taken by establishing standard conditions. Mean gray values were obtained by taking three measurements from each step of both the tooth and the aluminum step wedge, and the aluminum thickness equivalents were calculated. Statistical analysis was performed using one-way variance analysis and Tukey's test (P < 0.05). RESULTS: All aluminum thickness equivalents were found to be higher than those of the enamel and dentin, except Clearfil Majesty Esthetic (2.23 mm ± 0.52 mm) and Filtek Silorane (3.67 mm ± 0.15 mm) (P < 0.05). The Clearfil Majesty Posterior (8.50 mm ± 0.10 mm) and Arabesk Top (8.17 mm ± 0.06 mm) were found to be the most radiopaque composites. CONCLUSION: All composite resin materials tested in this study were confirmed to the International Standards Organization 4049 standards. However, since radiopacity is not the only criterion for clinical use, it is a better approach to take all other properties of the materials into consideration.

Inhalation of mercury vapor can cause the toxic effects on rat kidney.

Dental amalgam has been used in dentistry as a filling material. The filler comprises mercury (Hg). It is considered one of the most important and widespread environmental pollutants, which poses a serious potential threat for the humans and animals. However, mercury deposition affects the nervous, cardiovascular, pulmonary, gastrointestinal, and especially renal systems. In most animals' species and humans, the kidney is one of the main sites of deposition of mercury and target organ for its toxicity. In this study, the effects of mercury intake on kidney in rats were searched. For the this purpose; we used 24 adult female Wistar albino rats (200 g in weight) obtained from Experimental Research and Application Center of Atatürk University with ethical approval. Besides, they were placed into a specially designed glass cage. Along this experiment for 45 days, subjects were exposed to (1 mg/m(3)/day) mercury vapor. However, no application was used for the control subjects. At the end of the experiment, kidney samples were obtained from all subjects and processed for routine light microscopic level and stereological aspect were assessed. Finally, according to our results, mercury affects the histological features of the kidney. That means, the severe effects of mercury has been shown using stereological approach, which is one of the ideal quantitative methods in the current literature. In this study, it was detected that chronic exposure to mercury vapor may lead to renal damage and diseases in an experimental rat model.

Effect of mercury vapor inhalation on rat ovary: Stereology and histopathology.

AIM: Mercury, an environmental contaminant, is a risk factor for health in whole living organisms. In this study, we investigated whether mercury vapor (HgO) inhalation has an effect on rat ovary. METHODS: Twelve Wistar albino rats were divided equally into experimental (Hg) and control groups (n = 6). Animals in the Hg group were exposed to HgO for 45 days at a dose 1 mg/m(3)/day, after which, histological and stereological assessment were carried out. RESULTS: Ovaries exposed to HgO had histo-morphometric alterations. HgO inhalation resulted in reduction of the total number of primordial, primary and Graaf follicles. Also, mean volume of ovary, medulla and cortex, corpus luteum (c. luteum) and Graaf follicles was decreased in the Hg group. Moreover, there was a significant increase in total volume of the atretic follicles. On light microscopy, thickening of tunica albuginea, increase of fibrils within the connective tissue, congestion of the capillaries and venous vessels, thinned walls and fibrin deposition in some large blood vessels, and edema were seen. Also, irregular follicle and oocyte borders, and hydropic degeneration in follicular granulosa cells were detected. CONCLUSION: Structural alterations could be attributed to the toxic influence of HgO on rat ovary. The use of Hg should therefore be more controlled to minimize its toxic effect.

The Effect of Surface Treatments on the Bond Strength Between CAD/CAM Blocks and Composite Resin.

PURPOSE: The aim of this study was to evaluate the microtensile bond strength of three computer-aided design/computer-aided manufacturing (CAD/CAM) blocks repaired with composite resin using three surface treatment techniques. METHODS AND MATERIALS: Three different CAD/CAM blocks were used in this study: (1) Lithium disilicate, (2) feldspar ceramic, and (3) resin nano ceramic. All groups were further divided into four subgroups according to surface treatment: control, roughened with bur (B); roughened with bur and 5% Hydrofluoric acid (HF); roughened with bur and sandblasting (HF); and roughened with bur and CoJet (C). After surface treatments on each group, a silane and bonding agent were applied, and ceramics were repaired with a nano-hybrid composite. Then, the repaired ceramics were cut with a low-speed diamond saw for microtensile bond testing. Microtensile bond tests for 40 specimens per subgroup were carried out with a universal testing machine. The data were analyzed with ANOVA, Tukey's, and LSD at the 95% significance level. RESULTS: Mean bond strengths (MPa) of subgroups B, HF, S, and C were: 0, 29.8, 0, 23.3 for lithium disilicate ceramic; 26.4, 22.3, 22.4, 22 for feldspar ceramic; 54.8, 25.3, 42.1, 25.7 for resin nano ceramic. For subgroups B and S of lithium disilicate ceramics, bonding failed during specimen preparation. No significant differences were observed among all CoJet groups. In subgroups B and S, resin nano ceramics showed the highest bond strength. In feldspar groups, subgroup B showed higher bond strength than the other subgroups. CONCLUSION: This study demonstrates that lithium disilicate porcelain blocks required etching for repairing with composite material. Surface treatments did not increase the bond strength in feldspar ceramic groups and reduced the bond strength in resin nano ceramic groups.

Effects of composite restorations on nitric oxide and uric acid levels in saliva.

BACKGROUND AND AIMS: Dental materials that are used in dentistry should be harmless to oral tissues, and should, therefore, not contain any leachable toxic and diffusible substances capable of causing side effects. This study was intended to investigate the effects on salivary nitric oxide (NO) and uric acid (UA) levels after application of dental composite filling materials to healthy volunteers. MATERIALS AND METHODS: A total of 52 individuals (32 female and 20 male) participated in the study. Filtek Z250 composite filling material (3M ESPE, St Paul, MN, USA) was applied to healthy volunteers. Saliva samples were collected before restoration (baseline) and 1 h, 1-day, 7 days, and 30 days after restoration. NO concentrations were measured using the Griess reaction method, and UA was measured using an enzymatic method. Data were analyzed using repeated measures ANOVA and the Bonferroni post-hoc test (α =5%). RESULTS: NO values increased statistically significant after 7 days (P < 0.05). In addition, lower UA levels were determined compared to the baseline levels, but the difference was not statistically significant (P > 0.05). There was no correlation between NO and UA levels in saliva (P > 0.05). CONCLUSION: Composite resins activated the antioxidant system in saliva. However, further studies are now needed to confirm our findings and to permit a definitive conclusion.

The effect of sleep duration and quality on academical success of the elementary school children in Kayseri Turkey.

OBJECTIVE: To assess the sleeping habits of primary school children and establish link between sleeping hours and academic achievement. METHODS: The cross-sectional study was conducted between April and June 2007, involving 2422 students of 6-8th grades in 12 primary schools located in Kayseri, Turkey. A questionnaire was presented to the students on the basis of probability sampling method. Academic performance was evaluated with regard to their school grades. SPSS 20 was used for statistical analysis. RESULTS: Of the total 2422 questionnaires distributed, 1966 (81.2%) were used for further evaluation. The mean sleeping period of the students during school days was 8.86 +/- 1.10 hours. The number of students having difficulty in waking up in the morning was 940 (47.8%), while 910 (46.3%) were confused when they woke up during the night, and the 886 (45.1%) had nightmares, while 609 (31.0%) were sleepy all day long. As the sleeping period increased, the probability of a mediocre achievement in science lessons increased by 1.33 fold and poor achievement increased by 1.57 fold. Besides, the probability of a mediocre achievement in mathematics lessons increased by 1.36 fold, and poor achievement increased by 1.67 fold. For Turkish language lessons, these increases were found to be 1.40 and 1.60 respectively. Correlation analysis showed a significant negative relationship between sleeping time and successful scores in Turkish (r = -0.65, p < 0.025) and science (r = -0.061, p < 0.036) lessons. CONCLUSION: As the sleeping period increased, the academic achievement of the students was negatively affected. The academic success was low in children who felt sleepy throughout the day.

Evaluation of enamel pearls by cone-beam computed tomography (CBCT)

Objective: The aim of this study was to evaluate the frequency of enamel pearls according to population, sex and tooth groups on Cone-Beam Computed Tomography (CBCT) or Dental Volumetric Tomography (DVT) scans of patients, retrospectively. Study Design: In this study, 15185 teeth belonging to 768 patients, 430 female and 338 male, was performed cross sectional examination by CBCT. The volumetric Computed Tomography used in the study is Newton FP based on flat-panel. The data were analyzed with Pearson chi-squared test. Results: Enamel pearls were detected in 36 subjects (4.69%). Of these enamel pearls, 19 were detected in male and17 were in male. There was no statistically a significant association between prevalence of enamel pearls and sex. All of enamel pearls were detected in molar teeth, for prevalence 0.83%.Conclusion: All of enamel pearls are found upper and lower molar teeth, especially the most commonly in maxillary second and third molars (AU)

Effectiveness of surface protection for glass-ionomer, resin-modified glass-ionomer and polyacid-modified composite resins.

The purpose of this study was to evaluate the effectiveness of several surface protectors for a glass-ionomer, a resin-modified glass-ionomer, and a polyacid-modified resin cement by determining dye uptake spectrophotometrically. 378 samples, made up of Ionofil U, Vitremer, and Dyract, were prepared and divided into groups of seven each. Positive and negative control specimens remained unprotected while the experimental specimens were protected with Finishing Gloss, Protect-It, LC Varnish, Adper Single Bond, or a nail varnish. The experimental groups and positive controls were immersed in 0.05% methylene blue solution, while the negative controls were immersed in deionized water. Results were evaluated using variance analysis. Of the Ionofil U group, Adper Single Bond exhibited the least effective surface coating among the materials tested, while the best surface protection was obtained with LC Varnish in the Dyract group. However, no statistically significant differences were observed in the Vitremer group.

The effects of amalgam restorations on plasma mercury levels and total antioxidant activity.

OBJECTIVE: This study evaluated the effects of amalgam restorations on plasma mercury levels and total antioxidant activities (TAA). DESIGN: The study was comprised of 48 subjects ranging in age from 20 to 32 years. Of these, 33 had dental amalgam restorations and 15 had no dental amalgam restorations. In those patients with amalgams, the total number of amalgam restorations and surfaces were counted, and the total and occlusal areas (mm(2)) of restorations were measured using a Counting Measurement Machine. Blood samples were collected from all participants. Plasma mercury levels were measured using an Atomic Absorption Spectrometer and Hydride System, and plasma TAA levels were measured using an Antioxidant Assay Kit. Statistical analysis was performed using the SPSS 10.01 software program. Data was evaluated by t test and correlation analysis. RESULTS: Plasma mercury (P-Hg) levels were found to be significantly higher in subjects with amalgam restorations when compared to subjects without amalgams (p<0.01); the differences in P-TAA levels between subjects with and without amalgams were not found to be statistically significant (p>0.05). No significant correlations were found between P-Hg concentrations and P-TAA levels (p>0.05). Significant positive correlations were found between P-Hg concentrations and the number of amalgam restorations (p<0.01), number of amalgam surfaces (p<0.05), total amalgam surface area (p<0.05) and amalgam occlusal surface area (p<0.01). However, no significant correlations were found between these parameters and P-TAA (p>0.05). CONCLUSIONS: The results of our study showed that dental amalgams are a major source of plasma mercury; however, amalgam restorations were not found to have a significant effect on plasma-total antioxidant activities.

Effect of different surfaces and surface applications on bonding strength of porcelain repair material.

This study was done to analyze the effect of different surfaces and different surface applications on the bonding strength of porcelain repair material and to compare these factors with one another. Three different substructures of 10 mm diameter and 4 mm thickness were used for the repair surface: metal, metal on porcelain and porcelain. The surfaces of half of the samples were roughened with an air abrasion tool; the surfaces of the other half were treated with a diamond bur. The specimens were ultrasonically cleaned in distilled water. A silane coupling agent and a bonding agent were applied to the surfaces of all the samples. Resin composite was applied to each specimen. All specimens were stored in distilled water for 24 hours before being thermocycled. After thermocycling, specimens were stored in distilled water for an additional seven days before being subjected to a shear load. The highest bonding strength was observed in the samples with a metal substructure, the surfaces of which were prepared with an air abrasion tool; the lowest bonding strength was observed in the samples with a metal substructure, the surfaces of which were prepared with a diamond bur. When different substructures were examined in terms of bonding strength, the highest bonding strength was statistically observed in metal-on-porcelain substructures, and the lowest bonding strength was observed in the porcelain substructure. When they were examined in terms of surface processes, the highest bonding strength was statistically observed in the samples whose surfaces were prepared with an air abrasion tool, and the lowest bonding strength was observed in the samples whose surfaces were prepared with a diamond bur.

Prevalence and handedness correlates of traumatic injuries to the permanent incisors in 13-17-year-old adolescents in Erzurum, Turkey.

The objectives of the present study were to explore the relationship between dental trauma and handedness, and to assess the prevalence of traumatic injuries to the permanent incisors of 13-17-year-old patients, seeking treatment for various dental conditions in Erzurum, Turkey. A questionnaire focusing on handedness was administered to these patients. Handedness was assessed by the Edinburgh Handedness Inventory (Oldfield, 1971). Hand preference was divided into two classes for convenience in data analysis: (i) right-handers (GSc from 80 to 100); and (ii) left-handers (GSc from -80 to -100). This study included the 13-17-year-old group patients who had GSc as described above. Thus, the present study was carried out on 2180 (1252 male and 928 female, with a mean age of 14.9 years) out of 2392 patients. The clinical examinations and radiographic assessments were performed in full-designed dental chairs. Preliminary analysis showed no differences in rates of handedness with respect to sex and age. Overall, 10.4% of the patients were left-handers. A total of 292 (13.4%) of 2180 patients examined had one or more traumatized permanent incisors. The proportion of dental trauma was significantly higher in males than in females, 17.41% in males as compared to 7.97% in females; and ratio of the affected males to females was about 2.18. Sex difference in the prevalence of traumatized permanent incisors was statistically significant (P < 0.001). That is, males had a significantly higher risk of dental trauma than females (P < 0.001; odds ratio: 2.49; 95% confidence interval (CI) 1.88, 3.23). There was a higher level of traumatized permanent incisors among left-handers than among right-handers. 28.3% of left-handers and 11.7% of right-handers had dental trauma. This difference in the prevalence of traumatized permanent incisors for handedness was statistically significant (P < 0.001). Indeed, left-handers had a significantly higher risk on dental trauma than right-handers (P < 0.001; odds ratio: 3.09; 95% CI 2.23, 4.29). The primary causative factor in the occurrence of trauma was the fall (27.7%). Then came violence and fight as the second most frequent cause of trauma (24%), followed by sports injury (18.8%). Trauma resulting from collisions and traffic accidents were accounted as 13.7 and 11.3% of all cases, respectively. The other causes were 4.5%. In conclusion, the present study suggests that left-handed adolescents have more frequent permanent incisor tooth trauma than right-handed adolescents. Left-handedness, therefore, appears to be a risk factor for trauma in 13-17-year-old adolescents.

A survey of the correspondence between abrasions and tooth brushing habits in Erzurum, Turkey.

AIM: To determine whether there is a correlation between dental abrasions and the frequency and technique of tooth brushing, as well as to examine the prevalence of dental abrasion according to age and gender. MATERIALS AND METHODS: This study was carried out on 428 adults (242 female, 186 male) 20 years of age and older, who attended the Department of Operative Dentistry, Department of Oral Diagnosis and Oral Radiology Faculty of Dentistry, Atatürk University. RESULTS: The study revealed a statistically significant relationship between abrasive lesions and age groups as well as between abrasive lesions and gender. A statistically significant difference was determined between abrasions and tooth brushing frequency, while there was no statistically significant relation between abrasions and tooth brushing technique (p>0.05). CONCLUSION: The prevalence of tooth brushing abrasions increases with age, and lesions are seen more frequently in males than in females. Also, tooth brushing technique is not important to the presence of abrasions, but increased tooth brushing frequency results in an increase in the number of abrasions.