Comparative evaluation of bond strength and color stability of polyetheretherketone and zirconia layered with indirect composite before and after thermocycling: An in vitro study.

AIM: This study investigates the interaction of zirconia and polyetheretherketone (PEEK) with indirect composite in fixed dental prostheses. This investigation aimed to assess the shear bond strength (SBS) and color stability of zirconia and PEEK before and after aging, addressing critical concerns in dental restorative applications. SETTINGS AND DESIGN: The current in vitro study used 96 samples, 48 of which were divided into two groups, zirconia and PEEK, before and after thermocycling. A dual-axis chewing simulator was used for thermocycling. SBS was measured using a universal testing machine, and color stability was checked using a reflective spectrophotometer. MATERIALS AND METHODS: Ninety-six samples were categorized into zirconia and PEEK groups, each with subgroups undergoing thermocycling. Samples were prepared using computer-aided design/computer-aided manufacturing milling and veneered with composite resin. Thermocycling involved 10,000 cycles, simulating stress levels equivalent to approximately 1 year of clinical use. SBS was assessed using standardized tests. Stereomicroscopic analysis was performed to evaluate the type of failure. Color stability of the core materials with indirect composite was done using a spectrophotometer before and after aging. STATISTICAL ANALYSIS USED: Statistical analysis included paired t-tests and independent t-tests in SPSS software. RESULTS: The results revealed that SBS values for composite on PEEK decreased from 13.86 ± 0.164 MPa before thermocycling to 13.46 ± 0.185 MPa after thermocycling, with a significant difference (P < 0.005). However, both pre- and postthermocycling values for PEEK were higher than zirconia. The t-test confirmed the lower bond strength of composite to zirconia, with a noteworthy improvement after aging. Stereomicroscopic images revealed adhesive failure for the zirconia group and mixed (adhesive and cohesive) failure for the PEEK group. ΔE values were 3.21 ± 0.127 and 2.93 ± 0.142 for zirconia and PEEK groups, respectively (P < 0.005). CONCLUSION: Within the limitations of this study, it can be deduced that PEEK is a feasible substitute for zirconia when used in conjunction with indirect composite for the fabrication of dental prostheses.

A Comparison of the Edge Testing of Indirect Composite Layered Zirconia Crowns and Monolithic Zirconia Crowns Without Aging: An In Vitro Study.

Introduction The main reason veneered zirconia restorations fail is due to porcelain veneer chipping. This chipping usually starts from wear marks on the chewing surface. As a result, small cracks under the contact area can grow into larger ones across the veneer layer. The veneer ceramic layer is more vulnerable to fractures because it has lower toughness and slightly lower stiffness compared to the base framework material. Thus, even when there's significant chipping, the main framework material usually stays protected with a thin layer of veneer ceramic on top. The aim of this in vitro study is to compare the edge strength of Monolithic Zirconia Crowns with that of Indirect Composite Layered Zirconia Crowns without aging. Materials and methods This research involved creating 12 hand-layered all-ceramic crowns and 12 indirect composite layered zirconia crowns. The sample size was determined using a G*Power calculation (Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany). The zirconia frameworks (Upcera HT White; UPCERA Dental America Inc., Cerritos, CA, US) were milled and sintered following the manufacturer's instructions. For the all-ceramic group, veneering porcelain (e.max Ceram; Ivoclar Vivadent, Schaan, Liechtenstein) was hand-applied. In contrast, the indirect composite group utilized Ceramage (Shofu, Kyoto, Japan). An Instron 4501 universal testing machine (Instron Corp., Canton, MA, USA) was employed for the edge chipping tests, and a Vickers indenter (Shanghai Toyo Diamond Tools Co., LTD, Shanghai, China) was used to apply the load. The mean value for edge chipping was analyzed using an unpaired t-test with IBM SPSS Statistics for Windows, Version 26 (Released 2019; IBM Corp., Armonk, NY, USA). The normality of the data was confirmed, and statistical significance was set at 0.05. Results Monolithic Zirconia Crowns (Group 1) require significantly more force (mean: 405 N) to induce an edge chip compared to Indirect Composite Layered Zirconia Crowns (Group 2) (mean: 300 N). The 95% confidence interval (83.43261 N to 109.90072 N) confirms the statistical significance of this difference. Conclusion In conclusion, when evaluating restorative materials based on both esthetic and functional criteria, monolithic zirconia stands out due to its combination of strength, esthetic potential, biocompatibility, and versatility.

Comparative Analysis of Periodontal Parameters and Patient Satisfaction Utilising Different Temporary Crown Fabrication Techniques: A Parallel-Group Randomised Controlled Trial.

Aim The study aims to evaluate the efficacy of different techniques for temporary crown fabrication in maintaining periodontal health and patient satisfaction, addressing a critical gap in the existing literature and informing evidence-based clinical practices. Materials and methods This study, conducted in accordance with CONSORT guidelines, was a parallel-group randomised trial conducted at a dental institute in India. In total, 36 participants aged 18-65 requiring anterior tooth region crowns were randomly assigned to three groups: direct (control), indirect (Test Group 1) and direct-indirect (Test Group 2) fabrication techniques. Participants were selected from outpatient departments based on eligibility criteria, and interventions were allocated using randomization tables. Outcome assessments included gingival health metrics and patient satisfaction levels, with statistical analyses performed using the Kruskal-Wallis test. Results Significant differences were observed in the pink esthetic score (PES) and patient satisfaction (P=0.029) among the three groups, with the direct-indirect technique group demonstrating the highest median PES (9 out of 10). However, no significant disparities were noted in the plaque index (PI) or probing depth (PD) among the groups. Conclusion The direct-indirect technique demonstrated superior PES and patient satisfaction, indicating potential benefits for periodontal health and patient experiences. Integration of virtual preparation workflows may optimise outcomes, but further research is needed for validation and guideline development.

Assessment of Antimicrobial Activity of Nanocomposites Based on Nano-Hydroxyapatite (HAP), Chitosan, and Vitamin K2.

OBJECTIVE: The objective of this study was to evaluate the antimicrobial potential of nanocomposites containing vitamin K2, hydroxyapatite nanoparticles (nHAP), and chitosan (Chito)-coated dental implants against clinically relevant microbial strains. MATERIALS AND METHODS: Four test compounds were prepared: vitamin K2 + nHAP, K2 + Chito + nHAP, vitamin K2, and vitamin K2 + Chito. Agar well diffusion test was conducted to assess the antimicrobial activity of these compounds against Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), Enterococcus faecalis (E. faecalis), and Candida albicans (C. albicans). Results: The vitamin K2 + nHAP nanocomposite exhibited antimicrobial activity against all tested microorganisms, with E. faecalis showing the highest sensitivity (25 mm zone of inhibition at 100 µL concentration). The K2 + Chito + nHAP nanocomposite demonstrated potent antimicrobial activity with C. albicans displaying the highest sensitivity (28 mm zone of inhibition at 100 µL concentration). Pure vitamin K2 showed limited antimicrobial activity, vitamin K2 combined with chitosan exhibited significant susceptibility to C. albicans, resulting in a substantial inhibition zone of 24 mm diameter at a concentration of 100 µL. CONCLUSION: The synergistic effects of vitamin K2 with nHAP and chitosan highlight the potential of these nanocomposites for biomedical applications. These findings contribute to the development of effective nanocomposites to address antimicrobial resistance and improve infection control in various biomedical fields.

Therapeutic evaluation of titanium dioxide nanoparticles based herbal dental varnish derived from rosemary and ginger extracts:A comprehensive investigation into anti-inflammatory and antioxidant properties.

BACKGROUND: Titanium nanoparticles (NPs) offer promising applications in the treatment and prevention of inflammatory disorders due to their unique physicochemical characteristics. However, additional research is necessary to attain a thorough comprehension and validate the efficacy of this approach in dental practice. OBJECTIVE: This study scrutinizes the anti-inflammatory properties of a dental varnish infused with ginger and rosemary extracts mediated by titanium dioxide (TiO2) nanoparticles. METHODS: A herbal dental varnish was formulated by integrating ginger and rosemary extracts with titanium dioxide nanoparticles at concentrations of 10, 20, 30, 40, and 50 µL. Anti-inflammatory properties were assessed through Bovine Serum Albumin denaturation and membrane stabilization assays, comparing results with a control group. RESULTS: The results reveal concentration-dependent antioxidant and anti-inflammatory properties in the test group when compared to the control group. The BSA assay corroborates increased percent inhibition with rising titanium dioxide nanoparticle concentrations. In line with existing literature, titanium dioxide nanoparticles enhance dental material properties. CONCLUSION: The bioactive compounds in ginger and rosemary, such as phenolic compounds and terpenes, contribute to anti-inflammatory and antioxidant effects of the varnish. Additionally, the therapeutic potential of titanium dioxide nanoparticles in addressing inflammatory diseases underscores their significance in this formulation.

In Vitro Evaluation of Accuracy and Reliability of Tooth Shade Selection Using Different Digital Instruments.

Introduction Managing tooth shade is a significant challenge in aesthetic dentistry, especially for anterior restorations. Accurate shade assessment, combined with tailored treatment strategies and effective communication, is crucial. To improve the precision and reliability of aesthetic dental treatments, new shade-matching technologies have emerged. Current clinical methods for determining tooth shade utilize both visual assessments and instrumental techniques. The current study aimed to assess and compare the reliability and accuracy of four digital methods of tooth shade matching. Materials and methods This study utilized a 3D-printed resin upper arch model with tooth preparation done on tooth 11. An intraoral scanner was employed to scan and design the tooth, followed by the fabrication of 30 zirconia crowns using computer-aided design and computer-assisted manufacturing (CAD/CAM). The assessment of shade matching involved four digital photometric methodologies (group 1: twin flash + digital single-lens reflex (DSLR) camera (DT), group 2: ring flash + DSLR camera (DR), group 3: smartphone camera (SMART), group 4: intraoral scanner (IOS)) with Commission Internationale de l'Eclairage (CIEL*a*b*) values determined through Adobe Photoshop transformation. Accuracy (ΔE) was calculated and a specific shade using Vitablocs Mark II 3D-Master served as the standard. CIEL*a*b* data (where L = lightness, a and b = chromaticity coordinates) from four cohorts were analyzed in SPSS 26.0 for reliability, with intraclass correlation. The Kruskal-Wallis test and Spearman's correlation assessed reliability, while a one-sample t-test assessed accuracy, comparing values to clinical thresholds (p<0.05). Results The intraclass correlation revealed noteworthy variations in the L*, a*, and b* values, spanning from 0.730 to 0.994, 0.885 to 0.992, and 0.881 to 0.997, respectively. Intraoral scanners demonstrated high accuracy (ΔE = 5.8), while the SMART method showed the lowest precision (ΔE = 12.09). Twin flash with DSLR (TF+DSLR) and ring flash with DSLR (RF+DSLR) displayed comparable precision, with ΔE values of 10.90 and 10.97 respectively. Conclusion The smartphone exhibited the least precision, displaying notable discrepancies in all CIEL*a*b* metrics when compared to the manufacturer-specified shades. Conversely, the intraoral scanner demonstrated higher accuracy and reliability compared to the other groups, with no discernible variation in any of the CIEL*a*b* values from the manufacturer's standard.

Effectiveness of Photobiomodulation With Low-Level Laser Therapy on the Implant Stability Quotient at Different Time Intervals: A Randomized Clinical Trial.

Background Photobiomodulation techniques, particularly low-level laser therapy (LLLT), have gained traction due to their ability to accelerate osseointegration by stimulating cellular metabolism and promoting tissue healing. This study explores the effectiveness of LLLT around dental implants at various intervals after placement. Using resonance frequency analysis (RFA), the implant stability quotient (ISQ) was measured to assess implant stability. Methodology This split-mouth, randomized, single-blinded clinical trial included 20 participants undergoing dental implant placement. The test group received LLLT while the control group had no laser treatment. Implant stability was assessed using RFA at one, two, four, and twelve weeks post-implant placement. Statistical analysis involved descriptive statistics, repeated-measures analysis of variance (ANOVA), and t-tests. Results The repeated-measures ANOVA analysis showed significant differences in the ISQ values between the LLLT group and the control group at two weeks and three months post-implant placement. The LLLT group exhibited higher ISQ values, indicating greater implant stability and improved osseointegration compared to the control group. These findings suggest the potential benefits of LLLT in enhancing dental implant outcomes. Conclusions LLLT shows promise in improving dental implant outcomes, with enhanced stability and osseointegration. Further research is needed to validate these results and integrate LLLT into routine dental implant procedures.

An in vitro comparison of the marginal fit of provisional crowns using the virtual tooth preparation workflow against the traditional technique.

Aim: This study investigates the effectiveness of an innovative virtual tooth preparation workflow for the fabrication of dental crowns using cone-beam computed tomography (CBCT) and intraoral scanners (IOSs) with conventional workflow using extraoral/laboratory scanners. Settings and Design: This in vitro experimental study was conducted in the laboratory of a university in Chennai, India. The dental laboratory and research facilities at the institution were utilized for the fabrication of the temporary crowns and the data acquisition process. Materials and Methods: Institutional approval was obtained from the university. It was basically a comparison between the virtual prep technique using CBCT and IOS and the conventional digital technique using extra oral scanners (EOS) for temporary crown fabrication. The sample size was estimated using an effect size of 1.5004, assuming a normal distribution, a significance level of 0.05, and a power of 0.95 in G power software. Based on this calculation, an extracted second lower molar was used to fabricate 10 samples in each group. The samples were divided into three groups: the CBCT (Group 1), the IOS (Group 2), and laboratory scanner (Group 3 as control) groups. The vertical marginal gap of all the surfaces of the crown was evaluated using a scanning electron microscope. Statistical Analysis Used: Data were analyzed using one-way ANOVA using the SPSS software version 26.0, IBM, Armonk, NY, USA. Results: Acceptable marginal discrepancy values were obtained in all three groups. There was no significant difference in the marginal discrepancy recorded (P = 0.113). Conclusion: Virtual tooth preparation using CBCT and IOSs can be used as an alternative to the conventional workflow for provisional crown and bridge fabrication.

Evaluation of Peri-Implant Crestal Bone Loss with Different Implant Systems, Primary Stability, Bone Density and Soft Tissue Thickness: A Retrospective Study.

AIM: The purpose of this retrospective study was to compare, among various implant systems, the influence of primary stability and the bone density and soft tissue biotype of the patient on the amount of peri-implant crestal bone loss after 1 year using radiography. MATERIALS AND METHODS: Included in this retrospective study were patient records of 3583 implant placements utilized from an online dental information archiving software (DIAS). Clinical and radiographic assessments were conducted concurrently with implant placement (baseline) and 1 year post surgery. Statistical analysis was done to examine the mean marginal bone loss significance in the three different implant systems groups (group I: Straumann Roxolid SLAc-tive, group II: Nobel Biocare CC, group III: Straumann SLA), different primary stability values, different bone density. and soft tissue biotype at the time of implant placement. RESULTS: A significant difference was observed in the crestal bone loss with different implant systems used. Group I showed significantly lesser amounts of crestal bone loss when compared to groups II and III. However, the differences in the bone density, ISQ values, and the soft tissue biotype did not exhibit a statistically significant difference in the amount of crestal bone loss. CONCLUSION: Significant MBL preservation for implants with Straumann SLActive when compared to Nobel Biocare CC and Straumann SLA implants. No significant changes were observed with respect to primary stability, bone density, and soft tissue thickness and no correlation among early crestal bone loss and IT, ISQ at surgery, and ISQ at reopening was observed. Straumann Roxolid SLActive implants showed less crestal bone loss probably owing to its hydrophilic surface modification. However, more studies need to be done to evaluate the same.

Knowledge, Attitude, and Perception Regarding the Financial Aspects of Prosthetic Rehabilitation Using Dental Implants: A Double-Questionnaire-Based Study.

To assess up to date patient and doctor perceived costs of dental implant surgery among the Indian population as there is a lack of information regarding patients' awareness of dental implants. Two online questionnaire forms were sent over the internet to the Indian population and the Indian dentists and dental students regarding the knowledge, attitude and perception regarding the dental implant surgery for rehabilitation of a single missing tooth. Statistical analysis was then carried out using SPSS software version 23.0. Thirty-eight percent (P < 0.05) of the participants questioned the thought that implants require the same care as fixed prostheses, and thought it was a better option due to a major percent expecting an additional payment > 10,000 indian rupees. The expectations that patients have for an implant-supported set are high in contrast to their willingness to make additional payments. There are still misconceptions regarding costs, and these must be resolved individually in practice.

Comparative analysis of various temporary computer-aided design/computer-aided manufacturing polymethyl methacrylate crown materials based on color stability, flexural strength, and surface roughness: An in vitro study.

With recent advancements in digital dentistry, computer-aided design/computer-aided manufacturing (CAD/CAM) processed prostheses have been in very much use recently. This study aims to assess and compare the properties of these materials to better enable the practitioners to select the type of materials for use in a normal clinical practice. This research study was commenced after the approval by our Institutional Review Board (IHEC/SDC/PROSTHO/21/119). Twelve specimens of each group (group 1: CAD/CAM milled prostheses and group 2: three-dimensional (3D) printed prostheses using rapid prototyping) were prepared using the ISO standardization 10477:2004. The flexural strength of the samples that were prepared was tested using a universal testing machine and the values obtained were evaluated. Other samples (ISO standardized) were collected for evaluation of color changes postaging and surface roughness of both groups. Unpaired t-test to analyze flexural strength and surface roughness and Paired t-test was used to statistically analyze the values obtained for color stability. Group 1 showed significantly higher flexural strength and significantly better color stability when the samples were subjected to thermocycling. The mean strength obtained for 3D printed polymethyl methacrylate (PMMA) was 80.06MPa, whereas the mean flexural strength recorded for milled PMMA was 128.32 MPa. There was not much difference observed in the surface roughness of both groups. CAD/CAM milled specimens presented with better color stability and strength when compared to 3D printed specimens. Practitioners should be cautious while using three-dimensionally printed temporary prostheses in the posterior tooth region.

Comparative analysis of weld strength of nickel-chromium and cobalt-chromium base metal alloys when submitted to tungsten inert gas welding.

Long span base metal alloy fixed prosthesis and partial dental prosthesis frameworks most often require welding for better fit and adaptation. The type of metal alloys used and its effect on the weld strength of the prosthesis have to be investigated. The aim of the study is to comparatively analyze the weld strength of nickel-chromium (Ni-Cr) and cobalt-chromium (Co-Cr) base metal alloys when subjected to tungsten inert gas (TIG) welding. 10 nickel- and cobalt-based specimens were obtained by casting of castable resin patterns of dimension 25 mm × 3 mm × 1 mm. Welding of the samples was carried out using the Lampert PuK 2 welding equipment, and a three-point bend test using a universal testing machine was carried out to evaluate the weld strength of the specimens. Statistical analysis was carried out using the SPSS software version 23. Higher weld strength was observed in the Co-Cr alloy (mean = 898 MPa) than in the Ni-Cr alloy (mean = 690 MPa), when submitted to TIG welding (P < 0.05). TIG welding could be a better alternative for joining base metal alloys for long span edentulous cases, and cobalt-based alloys could be better alternatives to nickel-based alloys that usually tend to cause hypersensitivity reactions.