Mechanical Properties of Zirconia Materials with Different Translucency: An In Vitro Study.

PURPOSE: To investigate the biaxial flexural strength of zirconia materials with different translucency before and after aging procedures and to evaluate the effects of aging on hardness and surface characteristics. MATERIALS AND METHODS: A total of 90 disc-shaped specimens (n = 30 each) were prepared from translucent (Upcera-ST, Upcera Dental), high translucent (Katana HT, Kuraray Noritake), and ultra high translucent (Katana UTML, Kuraray Noritake) zirconia materials to a ø.16 ±1.2 mm thickness. The different translucency discs were then divided into three subgroups; one group was subjected to aging in a chewing simulator (n = 10), one group was aged with thermocycling (n = 10), and one was a control group (n = 10). Biaxial flexural strength, Vickers hardness, and surface characteristics were examined for all discs. The data were analyzed using the Shapiro-Wilk (P = .05), Mann-Whitney U, and Kruskal-Wallis H tests. Fracture strength was determined using biaxial bending strength tests, and Weibull analysis was used to analyze the resulting data. RESULTS: A statistically significant difference was found among zirconia materials with different translucency in terms of fracture strength. On average, fracture strength was highest in the Upcera ST group (1,932.87 MPa) and lowest in the Katana UTML group (1,073.6 MPa; P = .001). The results of Weibull analysis showed a statistically similar distribution for all groups. CONCLUSIONS: Aging procedures did not cause significant differences in fracture strength and hardness. The fracture strength of the zirconia materials with different translucency was considered acceptable for intraoral use.

Evaluation of the Effects of ß-Adrenergic Receptor-Propranolol on Osseointegration of the Titanium Implants.

ABSTRACT: This study aimed to investigate the effects of systemic propranol on the osseointegration of titanium implants. After the surgical insertion of titanium implants into the metaphyseal part of the tibial bone, the rats were randomly divided into 2 equal groups: the control (CNT) (n = 10) and propranol group (P) (n = 10); CNT: Rats received no further treatment during the 4 week experimental period after surgery. Rats received 10 mg/kg propranol in every day during the 4 week experimental period in PRP group after the surgical insertion of the implants. After the experimental period, the rats were euthanized, blood serum were collected to biochemical analysis and the implants and surrounding bone tissues were used for the histopathologic analysis. To analysis of the data between tests and controls student T test was used. There were no significant differences in the biochemical parameters (alcaline phosphatase, calcium, phosphor) of the groups (P > 0.05). Bone implant connection (BIC) ratios was detected higher in test animals compared with the controls (P < 0.05). Systemic propranolol may increases titanium implant osseointegration.

Biomechanical and Biochemical Analyses of the Effects of Propranolol on the Osseointegration of Implants.

ABSTRACT: This study aimed to investigate the effects of systemic propranolol on the osseointegration of titanium implants. After the surgical insertion of titanium implants into the metaphyseal part of the tibiae of rats, the rats were randomly divided into three equal groups: the control (n = 8), propranolol dosage-1 (PRP-1) (n = 8), and propranolol dosage-2 (PRP-2) (n = 8) groups. In the control group, the rats received no further treatment during the 4-week experimental period after the surgery. After the surgical insertion of the implants, the rats in the PRP-1 and PRP-2 groups were given 5 mg/kg and 10 mg/kg propranolol, respectively, every 3 days for the 4-week experimental period. After the experimental period, the rats were euthanized. Blood sera were collected for biochemical analysis, and the implants and surrounding bone tissues were used for the biomechanical reverse torque analysis. One-way ANOVA and Tukey's honest significant difference test were used for statistical analysis. The student t-test was used to analyze the data obtained from the tests and the controls. There were no significant differences in the reverse torque analysis results and the biochemical parameters (alkaline phosphatase, calcium, and phosphorus) of the groups (P > 0.05). Alkaline phosphatase was, however, found to be higher in test animals compared to the controls (P < 0.05). Also, propranolol did not biomechanically affect the osseointegration of titanium implants, while alkaline phosphatase activity was higher in the test animals.

Evaluation of the effects of finish line type and width on the fracture strength of provisional crowns.

This study aimed to investigate the impacts of finish line type and width on the fracture resistance of provisional crowns, and to determine the suitable type of crown material to use for that purpose. Chamfer and rounded shoulder preparations were done with stainless steel master models with a width of 0.6 mm and 1.0 mm and a total convergence angle of 6°. The provisional crowns were obtained using computer-aided design/computer-aided manufacturing (CAD/CAM) polymethyl methacrylate (PMMA) material in the mandibular left first molar. From the obtained molar tooth, a silicon mold was used to obtain the provisional crowns from the CAD/CAM PMMA, bis-acrylic resin, and self-curing composite materials. The lowest fracture strength was found in the bis-acrylic resin group made using the rounded shoulder preparation with a width of 0.6 mm (699 N). The highest fracture strength was found in the CAD/CAM PMMA group made using the rounded shoulder preparation with a width of 1 mm (1339 N). The fracture strength is higher for CAD/CAM PMMA than the other provisional crown materials; thus, it is recommended that this material be used in provisional crown restorations due to its other advantages.

The effects of metformin on the bone filling ration around of TiAl6Va4 implants in non diabetic rats.

OBJECTIVES: In this research it was aimed to that evaluation of the effects of systemic metformin administration on the periimplant bone tissue response of TiAl6Va4 implants in experimental rat model. MATERIALS AND METHOD: Firstly TiAl6Va4 implants were inserted surgically in the metaphyseal part of the tibial bone and after, the rats were randomly separated into two groups: Controls (CNT) (n = 10) and Metformin group (M) (n = 10). No additional treatment was applied to the controls during the 4-week experimental period. Rats received 40 mg/kg metformin in every day during the four week experimental period in M group. At the end of the 28-day follow-up period, the TiAl6Va4 implants with surrounding bone were used for the histopathologic analysis. To analysis of the datas between M and CNT Student-T Test was used. RESULT: Periimplant bone tissue filling ratios (%) were detected higher in M group compared with the CNT (P < 0.05). CONCLUSION: Systemic administration of metformin may increases titanium implant osseointegration in non-diabetic rats.

Evaluation of the accuracy of the mechanical torque wrench by the number of uses and ratchet type.

PURPOSE: To evaluate the accuracy of mechanical torque rachet types based on the number of uses. METHODS: A total of 25 ratchets, including three frictional- and two spring-type torque ratchets from every mechanical torque ratchet group, were used in our study. A digital torque measurement device was used in assessing the efficiency of mechanical torque ratchets. All ratchets were tightened according to the torque values recommended by the companies. The ratchets were tightened 500 times in total. RESULTS: Given the changes in torque delivery by the number of uses, a statistically significant torque loss was observed in the Bego ratchets (P< 0.05), and a statistically significant increase was found in the torque values of the other ratchet groups (P< 0.05). The highest increase in torque values was obtained in the MEDENTIKA ratchet group. CLINICAL SIGNIFICANCE: This study showed that there are changes in the torque values applied based on the number of rachet uses. Thus, clinicians are advised to regularly evaluate the accuracy of the rachets.

The effects of morus nigra on the alveolar bone loss in experimentally-induced periodontitis.

PURPOSE: The aim of this study is to evalute the anti-inflammatory effects of morus migra on experimentally-induced periodontitis in rats. MATERIALS AND METHODS: Twenty-four Wistar-albino rats were randomly divided into three groups: control group (C, n=8), experimental periodontitis (PER, n=8), experimental periodontitis and treated with Morus nigra (MN+PER, n=8) (50 mg/kg per day for 21 days). After 21 days, the rats were sacrificed, and alveolar bones were evaluated histopathologically and histometrically analyzed to obtain level of alveolar bone loss. The detection of RANKL and OPG were immunohistochemically performed. Serum and tissue levels of MMP-8 and MMP-13 were also analyzed. RESULTS: Morus nigra treatment decreased tissue MMP-8 and MMP-13 levels and there were significant differences in the case of tissue levels of MMP-8 and MMP-13 between groups PER and MN+PER (p=0.035, p=0.041). There were no significant differences among all the groups serum levels of MMP-8 and MMP-13 (p=0.067, p=0.082). In the histometric evaluation, alveolar bone loss was greater in the PER group compared to C and MN groups (p=0.035). Immuno-histochemical staining of RANKL activities were found significantly lower (p=0.037) and OPG activities were found significantly higher in MN+PER group when compared to PER group (p=0.021). CONCLUSION: The present study reveals that systemic administration of Morus nigra significantly inhibited the regional alveolar bone resorption and contributes to periodontal healing in the rat experimental-periodontitis models.

Spectrophotometric Evaluation of Anterior Maxillary Tooth Color Distribution According to Age and Gender.

PURPOSE: To determine the effects of age and gender on the color distribution of the right maxillary central, lateral incisors, and canine teeth. MATERIALS AND METHODS: The tooth color was measured using the VITA Easyshade V spectrophotometer with a total of 202 volunteers (89 men, 113 women). The age distribution in this study was between 15 and 70 years old (average: 31). A grey background color was used to prevent background reflection while performing the color measurements. RESULTS: According to the VITAPAN Classical shade guide, the tooth color distribution of the central and lateral incisors showed a maximum of A2, with a maximum of B3 for the canine teeth. When comparing the International Commission on Illumination L* , a* , and b* values (CIELab color space coordinates) of the teeth with subject gender, statistically significant differences were not found between gender and the L* and b* values (p > 0.05); however, a statistically significant difference was observed between gender and the a* values (p < 0.05). CONCLUSION: When the distribution ratio of tooth color was examined, different ratios were determined based on gender and age and between the maxillary central, lateral incisors, and canine teeth. A uniform tooth color should not be chosen for anterior restorations, and factors such as gender and age should be considered when making a color selection for patients.

Effects of Local and Systemic Zoledronic Acid Application on Titanium Implant Osseointegration: An Experimental Study Conducted on Two Surface Types.

The aim of this study was to evaluate the effects of local and systemic zoledronic acid (ZA) applications on titaniumoksit ceramic blasted (TiO-CB)- and sandblasted large acid-grit (SLA)-surfaced titanium implant osseointegration. Twelve New Zealand White rabbits were used in the study, divided into 6 groups: the TiO-CB (TiO-CB-CNT) (n = 2) and SLA (SLA-CNT) (n = 2) control groups in which TiO-CB- and SLA-surfaced titanium implants were surgically inserted into rabbit tibias but no treatment was applied; the TiO-CB (TiO-CB-LZA) (n = 2) and SLA (SLA-LZA) (n = 2) local ZA groups in which 1 mL of normal saline solution containing 2 mg of ZA was injected into sockets and after this the implants were integrated; and the TiO-CB (TiO-CB-SZA) (n = 2) and SLA (SLA-SZA) (n = 2) systemic ZA groups in which a single infusion of 0.1 mg/kg of ZA was administered during surgical implant insertion. Following a period of osseointegration, bone implant contact (BIC) was recorded as a proportion of the total implant surface length in direct contact with the bone. Results of this study indicate that BIC was greater in the systemic ZA application groups than in the local ZA application groups, and BIC was greater in the local ZA groups than in the controls. Statistically significant differences in BIC were not detected between the TiO-CB- and SLA-surfaced implants in all the groups. Furthermore, this study did not reveal significant differences between the 2 types of surfaces due to similar average roughness values. Overall, systemic ZA application was found to be more effective in increasing BIC than local ZA application based on the results obtained by testing 2 implant surfaces.

Is there a relation between dental anxiety, fear and general psychological status?

BACKGROUND: Dental anxiety is a widespread problem in many populations. This problem can be a barrier to dental care and may lead to poor oral health. Dental anxiety may be related to psychological status. AIMS: The aim of the present study was to assess the levels of dental anxiety, dental fear, Beck Depression, and state-trait anxiety according to age, gender and education level in patients at the periodontology clinic in the Diyarbakir Mouth and Dental Health Center. STUDY DESIGN: A total of 231 patients (115 males, 116 females) filled out dental fear scale (DFS), dental anxiety scale (DAS), Beck Depression Inventory (BDI), state-trait anxiety inventory-state (STAI-S), and state-trait anxiety inventory-trait (STAI-T) questionnaires, and evaluations of DFS, DAS, BDI, STAI-S, and STAI-T were conducted according to age, gender, and education level. RESULTS: The mean DFS, DAS, BDI, STAI-T, and STAI -S were 45.64, 9.15, 13.16, 38.90, and 40.18, respectively. There was a significant association among DFS, DAS, BDI, STAI-S, and STAI-T (p < 0.05). These surveys scores were significantly higher in females than males (p < 0.05). The results of this study indicated that gender age and education level have important effects on DFS, DAS, BDI, STAI-S, and STAI-T (p < 0.05). CONCLUSION: Dental anxiety and dental fear were found to be related to psychological status (BDI, STAI-S, and STAI-T) over time. There are some patients with unaddressed psychological distress.

Evaluation and comparison of the marginal adaptation of two different substructure materials.

PURPOSE: In this study, we aimed to evaluate the amount of marginal gap with two different substructure materials using identical margin preparations. MATERIALS AND METHODS: Twenty stainless steel models with a chamfer were prepared with a CNC device. Marginal gap measurements of the galvano copings on these stainless steel models and Co-Cr copings obtained by a laser-sintering method were made with a stereomicroscope device before and after the cementation process and surface properties were evaluated by scanning electron microscopy (SEM). A dependent t-test was used to compare the mean of the two groups for normally distributed data, and two-way variance analysis was used for more than two data sets. Pearson's correlation analysis was also performed to assess relationships between variables. RESULTS: According to the results obtained, the marginal gap in the galvano copings before cementation was measured as, on average, 24.47 ± 5.82 µm before and 35.11 ± 6.52 µm after cementation; in the laser-sintered Co-Cr structure, it was, on average, 60.45 ± 8.87 µm before and 69.33 ± 9.03 µm after cementation. A highly significant difference (P<.001) was found in marginal gap measurements of galvano copings and a significant difference (P<.05) was found in marginal gap measurements of the laser-sintered Co-Cr copings. According to the SEM examination, surface properties of laser sintered Co-Cr copings showed rougher structure than galvano copings. The galvano copings showed a very smooth surface. CONCLUSION: Marginal gaps values of both groups before and after cementation were within the clinically acceptable level. The smallest marginal gaps occurred with the use of galvano copings.