Purpose: This in vitro research was done to evaluate the influence of surface coatings on corrosion behavior of boron nitride (BN) and aluminum oxide (Al₂O₃) coated implant grade titanium alloy [titanium/Al/vanadium alloy (Ti-6Al-4V)] in artificial saliva. Materials and methods: Disk-shaped implants graded Ti-6Al-4V were divided into three groups, each having 10 samples. Chemical liquid deposition technique was used to coat 10 samples with BN and 10 samples with Al₂O₃ liquid, and 10 were kept uncoated (control group). Scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX) was performed to check the uniformity of coating. Linear polarization corrosion test was carried out in artificial saliva solution to assess the corrosion behavior of samples. Independent t-test was used to compare the mean scores for coating width. One-way analysis of variance (ANOVA) was used to compare the polarization resistance (Rp) of different groups. Pairwise comparison was done using a post hoc test. Results: Homogenous coatings with mean thicknesses of 13.86 and 14.32 μm and weight% 51.69 and 57.2 of B and AI were found, respectively. At 24 hours, the Rp value in the control group was highest (489.04 kΩ), while at 72 hours, it was lowest (485.54 kΩ) as compared to the test groups, and difference was statistically significant (p = 0.001). At 72 hours, AI-coated samples displayed the highest corrosion resistance value (863.71 kΩ). Conclusion: The results demonstrated that titanium implants can be successfully coated with BN and Al₂O₃, and this coating improves the corrosion resistance of dental implants.

Purpose: To evaluate and compare the effect on water sorption and solubility of acrylic-based and silicone-based soft denture lining materials stored over a period of 7, 14, and 28 days in three different storage mediums [distilled water (AW), artificial saliva (AS), and denture cleaner (AC)]. Materials and methods: A total of 66 disk-shaped samples were fabricated and divided into two groups depending on the soft-liner used—acrylic (A; n = 33) and silicone (S; n = 33). The samples were subdivided further depending on the solution immersed—AW [synthetic water (SW); n = 11 each]; AS [simulated saliva (SS); n = 11 each]; and AC [solution for cleaning (SC); n = 11]. The samples were dried and weighed to measure the initial weight of the disks. All the samples were stored in their respective solution jars. On days 7, 14, and 28, the samples were reweighed to measure the weight after sorption. Water solubility and water sorption were calculated for the groups. The data collected was statistically analyzed by one-way analysis of variance (ANOVA) test and independent samples t-test. Results: There is a significant difference in group A sorption and solubility values between the subgroups at days 7 and 28, having the highest sorption value for AC (0.7393 mg/cm²), followed by AW (0.659 mg/cm²) and then AS (0.6439 mg/cm²). The highest solubility was seen in the AS (0.525 mg/cm²) and the least in the AW (0.460 mg/cm²). In group S, sorption was seen highest in AW (1.1027 mg/cm²) and the highest water solubility was seen in the AW group (0.5055 mg/cm²) and least in the denture cleanser group (0.4850 mg/cm²). The mean water sorption values of the acrylic resilient liner were significantly greater (p < 0.001) than silicone-based liners in at 7–28-day time period. There was a continuous rise in water sorption up to day 14, and later it rose marginally. Conclusion: The silicone soft liners have a lesser sorption and solubility rate than the acrylic-based soft liners. In comparison to soft liners made of acrylic and the silicone soft liners may provide better clinical success.

Purpose: To compare the effect of hard and soft splints on muscle activity and self-reported clinical outcomes in patients with moderate to severe tooth wear at different intervals. Materials and methods: Participants within the age range of 18–45 years having moderate to severe wear of teeth were allocated into group I^HS (n = 8) receiving hard splints and group II^SS receiving soft splints. Electromyography (EMG) activity of masseter and anterior temporalis were recorded during postural rest position (PRP) and maximum voluntary clenching (MVC) at baseline (T0), 24 hours (T1), 4 weeks (T2) and at 8 weeks (T3) with and without splint. EMG activity of controls with no or minimal tooth wear was recorded only at baseline. Nonparametric tests were used for within-group and intergroup comparisons, followed by post hoc analysis with Bonferroni correction. Results: Baseline EMG activity was higher in experimental groups than that of controls, but the difference was nonsignificant (p > 0.05). At 24 hours, both the groups showed significantly lower (p < 0.05) EMG activity with the splint as compared to without the splint. Hard splints led to decreased muscle activity, while soft splints led to an increase at 4 and 8 weeks as compared to baseline EMG activity of controls, and the difference was nonsignificant except for anterior temporalis during MVC in group I^HS. The intergroup comparison revealed insignificant differences at all time intervals (p > 0.05), while it was significant for anterior temporalis in MVC at 4 and 8 weeks (p < 0.05). Conclusion: Muscle activity varied with different materials of the splint and duration of use. Both splints helped in the adaptation of muscles to new vertical dimensions of occlusion at 8 weeks with lesser variation between with and without splint position. The effect of the splint was more pronounced on the activity of the anterior temporalis than the masseter muscle.

Purpose: The purpose of this in vitro study was to evaluate and compare the surface roughness (Ra) and adhesion of Candida albicans (C. albicans) on conventional heat-cured, injection-molded thermoplastic resin and computer-aided design/computer-aided manufacturing (CAD-CAM) denture base resin as affected by denture cleanser solution at baseline, 15, 30, and 45 days. Materials and methods: A rectangular-shaped metal die was fabricated to make heat-cure (n = 80) and injection-molded thermoplastic denture base resin (n = 80) disks of uniform dimensions, whereas CAD-CAM disks (n = 80) were made by scanning the wax disk and milling of polymethylmethacrylate (PMMA) block. All the 240 specimens were immersed in the two different solutions, that is, artificial saliva solution (n = 120) as the control group and denture cleansing solution (n = 120) as a test group for a period of 0, 15, 30, and 45 days for 8 hours, respectively followed by Candida colonization. The Ra was evaluated by surface profilometer SJ-201, followed by the measurement of Candida colonization. The statistical analysis was done using repeated measures analysis of variance (ANOVA) test, one-way ANOVA, and independent t-test. Results: The Ra of heat-cured cured samples were 0.87 ± 0.01, 0.85 ± 0.02, 0.84 ± 0.02, and 0.83 ± 0.02 μm; injection-molded thermoplastic resin samples were 1.03 ± 0.01, 1.03 ± 0.04, 1.02 ± 0.03, and 1.00 ± 0.05 μm; and of CAD-CAM resin samples were 0.42 ± 0.01, 0.41 ± 0.02, 0.40 ± 0.03, and 0.40 ± 0.03 μm, respectively, when immersed in artificial saliva at baseline and intervals of 15, 30, and 45 days. The Ra of heat-cured samples were 1.12 ± 0.011, 1.21 ± 0.008, 1.25 ± 0.011, and 1.56 ± 0.008 μm; injection-molded thermoplastic resin samples were 1.31 ± 0.010, 1.45 ± 0.008, 1.76 ± 0.010, and 2.26 ± 0.014 μm; and of CAD-CAM resin samples were 0.86 ± 0.016, 1.07 ± 0.008, 1.12 ± 0.008, and 1.18 ± 0.015 μm, respectively, when immersed in denture cleansing solution at baseline, 15, 30, and 45 days. A similar trend was visible in the adherence of Candida to the denture base resins; the least adherence was seen in CAD-CAM resin, followed by heat-cured resin and injection-molded thermoplastic denture base resins. Conclusion: Within the limitations of the study, it was concluded that CAD-CAM denture base resins may be the preferred choice over conventional heat-cured or thermoplastic denture base resins for the fabrication of removable dental prosthesis to minimize Candida adherence and thus preventing opportunistic fungal infections in geriatric individuals.

Purpose: An in vitro study to evaluate and compare the bond strength of veneered porcelain as affected by the addition of recast nickel-chromium alloy in varying percentages using the universal testing machine (UTM) and to analyze the oxide layer on the metal specimens using the scanning electron microscope (SEM) and energy-dispersive X-ray (EDX). Materials and methods: Forty disk specimens of dimension 8 × 2 mm were fabricated from Bellabond Plus alloy (Bego, Germany) using recast metal in different (n = 10 samples/group) (group I: 100% fresh metal; group IIA: 75% fresh metal and 25% recast metal; group IIB: 50% fresh metal and 50% recast metal; and group IIC: 25% fresh metal and 75% recast metal). Application of commercially available porcelain (Ceramco 3) was done up to a thickness of 2 mm. Samples were then placed under SEM for EDX examination to evaluate ionic changes that occurred at the metal–ceramic interface. Bond strength of each sample was evaluated under UTM. The statistical analysis was done using one-way analysis of variance (ANOVA) test and post hoc test. Results: The one-way ANOVA showed that for the oxide layer content, a significant difference was seen in the values of chromium, nickel, and oxygen (p < 0.001). As the content of recast metal in sample increases, there is a significant decrease in the bond strength value, thus making the metal−ceramic bond weaker (p < 0.001). On performing the Tukey honestly significant difference (HSD) test, values were significant for nickel, chromium, and oxygen in the oxide layer content among different groups of new and recasted metal alloys (p < 0.05) and were not significant for silica, aluminum, and sulfur (p > 0.05). Conclusion: As the content of recasted metal increases, there is a decrease in the bond strength and increase in oxygen content in oxide layer. An adequate bond strength of 40 MPa was not achieved if the recasted metal is >50%. Thus, the data revealed that we could use up to 50% of recasted metal for prosthesis fabrication; beyond this limit, the bond strength is not adequate for dental use.

Purpose: The purpose of the study was to comparatively evaluate these new gingival displacement materials for their efficacy when compared with the conventional chemomechanical gingival displacement method. Materials and methods: This randomized control trial was carried out on 25 individuals according to the inclusion and exclusion criteria for gingival displacement using a retraction cord impregnated with aluminum chloride, ExpaSyl, and NoCord vinyl polysiloxane (VPS) impression system using Latin block design to evaluate the gingival displacement produced by three different tissue displacing materials on a right central incisor. Impressions were poured into the die stone. Casts were retrieved, and sections were made using a die cutter. Each slice thus obtained was evaluated under an optical microscope and transferred to the image analyzer to measure the amount of gingival retraction. The recorded values were statistically evaluated using the one-way analysis of variance (ANOVA) test, followed by the Tukey post hoc test for multiple comparisons. Results: The amount of mean gingival displacement produced by retraction cord impregnated with astringent solution was 1.42 ± 0.32 µm, by ExpaSyl retraction paste was 1.40 ± 0.11 µm, and that by NoCord VPS impression was 0.62 ± 0.12 µm when subjected to one-way ANOVA which showed highly statistically significant difference (p = 0.001 )among all the three groups with respect to gingival displacement. NoCord Impression system produced optimum tissue displacement as compared to the other two techniques. Conclusion: The retraction cord produced the maximum tissue displacement, followed by ExpaSyl, and the least displacement was caused by NoCord, although all displacement methods compared produced the optimum displacement required for impression making.

Purpose: The purpose of the present study was to evaluate the soft tissue changes and inflammatory markers with two different surface-treated implants. Materials and methods: A total of 20 patients were randomly divided into two groups; group I—implants with sandblasted, large-grit, acid etched treatment (SLA) and group II—implants with SLA with superhydrophilic treatment (mSLA). Soft tissue changes [probing depth (PD), bleeding on probing (BOP)] and inflammatory marker [interleukin-6 (IL-6)] count were evaluated and compared after 16 and 24 weeks of implant placement. Paired t-test and unpaired t-test were done for intergroup and intragroup comparison. Results: There was no effect of surface treatment on PD, BOP, and IL-1β load. There was a significant increase in PD (p < 0.0001) and inflammatory marker load (p < 0.0001) at 24 weeks when compared to 16 weeks in both implants, while BOP was not found to be significant after 24 weeks. Conclusion: Surface treatment modification for superhydrophilicity does not influence PD and BOP as well as cytokine levels. Probing depth increased significantly after loading irrespective of implant type. Similarly, there was also a significant difference in inflammatory marker load after loading in both implant groups.. Surface treatment didn't influence soft tissue parameters and inflammatory marker load.

Purpose: The purpose of the study was to evaluate and compare the linear dimensional stability of three types of denture base polymers—computer-aided designing/computer-aided manufacturing (CAD/CAM) resin, three-dimensional (3D) printed resin, and heat-cured polymethylmethacrylate (PMMA), subjected to immersion in artificial saliva and thermocycling. Materials and methods: A total of 300 test specimens were fabricated and divided into six groups (n = 50 each); [groups I and IV—CAD/CAM resin (Ivotion, Ivoclar Vivadent, Liechtenstein), groups II and V—3D printed resin (NextDent, 3D Systems, Netherlands), groups III and VI—PMMA denture base resin (Vertex BasiQ, 3D Systems, Netherlands)]. The dimensions of groups I, II, and III were measured with an accuracy of 0.02 mm with a digital caliper (Wireman, Brighton, United Kingdom), then they were immersed in artificial saliva for three intervals (7, 14, and 1 month), and measured after each period. Groups IV, V, and VI were subjected to thermocycling for 100 hours (5,000 cycles) between water baths of 5 and 55^oC, then immersed in artificial saliva for the same intervals and measured again. The obtained data were submitted to a one-way analysis of variance (ANOVA) and the mean values were compared by the Tukey test. Results: The results obtained indicated that the distinctions in linear stability among denture base polymers manufactured via 3D printing, CAD/CAM milling, and conventional methods are most noticeable following a 7-day immersion in artificial saliva. During this period, the 3D-printed dental resins exhibited higher average values. Over the course of 14 days and 1 month, the various groups demonstrated similar mean values, while the heat-cured conventional PMMA displayed greater linear stability. Conclusion: To summarize, during the initial week of the study, 3D-printed denture base materials displayed more significant linear alterations, whereas CAD/CAM milled, and traditional resins showcased better resistance to dimensional changes throughout the entire test duration. It's important to note that substantial linear changes were observed in all groups after undergoing thermocycling. In the subsequent two observation periods, both CAD/CAM milled, and 3D-printed dental resins exhibited lower linear stability compared to conventional PMMA.