Comparative Accuracy of Intraoral and Extraoral Digital Workflows for Short Span Implant Supported Fixed Partial Denture Fabrication: An In Vitro Study.

BACKGROUND The advent of digital impressions using computer-aided design and manufacturing technology (CAD/CAM) has simplified and improved the fabrication of implant prostheses in dentistry. The conventional impression has several drawbacks, including tray selection, material type, impression technique, impression disinfection, and cast model storage. The inaccuracies caused by distortion and contraction of impression material can be minimized with digital impressions. This study aimed to compare digital dental impressions of 10 working casts made using the Pindex laser removable die system to fabricate parallel drill channels vs 10 working casts made using the Di-Lok plastic tray removable die system. MATERIAL AND METHODS An implant master die with 2 dental implant analogs was fabricated. Ten working casts using the Pindex laser removable die system with parallel drill channels and 10 working casts using the Di-Lok plastic tray removable die system were fabricated. The working casts were scanned using an extra-oral laboratory scanner and the implant master model was scanned with an intra-oral scanner. RESULTS The properties of the casts made using the 2 systems were evaluated and analyzed with ANOVA and post hoc Tukey test. The mean horizontal linear distances between A1B1 (P<0.021), A2B2 (P<0.018), C1D1 (P<0.026), C2D2 (P<0.03), B1C1 (P<0.01), and mean vertical distances between B1A2 (P<0.015), C1D2 (P<0.001), B1B2 (P<0.028), and C1C2 (P<0.001) were significantly different between the Pindex system and Di-Lok tray system as compared to intra-oral scans. CONCLUSIONS Complete digital workflow with intra-oral scans were more than the partial digital workflow with extra-oral scans for the Pindex system and Di-Lok tray systems.

Impact of Auxiliary Features on Retention of Short Dental Crowns: An In-Vitro Analysis of Box and Groove Preparations.

BACKGROUND Several auxiliary features have been proposed to achieve sustainable retention for short-prepared dental crowns; however, achieving retention is challenging. This study aimed to assess the impact of increased total occlusal convergence and auxiliary preparation factors like box and groove on the retention form of short tooth preparations. MATERIAL AND METHODS Eighty resin machine-milled dies with a height of 3 mm and a deep chamfer margin of 1 mm were prepared to mimic the short-prepared molar. Initially, 2 teeth were prepared following the guidelines, and the total occlusal convergence was kept at 10° and 20°, respectively. Auxiliary features such as the proximal box and buccal groove were prepared on separate 20° dies. Eighty dies were prepared with 10 samples each for 10°, 20°, 20° with proximal box and 20° with buccal groove for zirconia (n=40) and metal crowns (n=40). Cementation was done with glass ionomer luting cement, and a pull-off test was conducted. Data were analyzed using one-way analysis of variance and post hoc fisher least significant difference test (P<0.05). RESULTS The highest mean was observed in the proximal box group with the metal crown (14.59), and the lowest in the group with 20° zirconia crowns (9.12). Within groups, the highest retentive values were found for the 20° taper with proximal box preparation; the lowest was for the 20° taper group. CONCLUSIONS Within the study limitations, it could be concluded that incorporating a proximal box or buccal groove in short tooth preparations with an increased total occlusal convergence improved retentive values.

Comparative Evaluation of Dimensional and Occlusal Accuracy of Non-Working Antagonist Casts: A Study on Different Impression Materials and 3D Printing.

BACKGROUND The aim of this study was to assess and compare the vertical/horizontal dimensions and occlusal accuracy of non-working/opposing casts obtained from three different impression materials and 3D print cast. MATERIAL AND METHODS Dentulous Master models simulating a case of a fixed dental prosthesis were mounted on an articulator (control group). Opposing mandibular casts obtained from three different impression materialsand 3-dimensional print constituted test groups , ,and , respectively. Three points, anterior vertical (AV), posterior vertical (PV), and anteroposterior (AP) were compared for dimensional accuracy among casts. Occlusal accuracy was analyzed on Medit Link software at 3 teeth (#13, #17, and #27). After calculating means for each group, the differences were calculated at probability value of P≤0.05 using the single-sample t test, ANOVA, and Tukey test. RESULTS The dimensions were significantly different from those of the mounted master models except in Gp AL(E) and Gp AL(F) at AV dimension and Gp AL(E) at AP dimension (P>0.05). A statistically significant difference of the error of means among the 4 tested groupswere detected only at 2 dimensions (AV and PV) between the Gp AL(E) and Gp 3D-C and between Gp AL(F) and Gp 3D-C groups. Other groups showed no significant differences. CONCLUSIONS The opposing casts obtained from the extended-pour alginate and alginate alternative impression materials showed higher occlusal accuracy compared to conventional alginate and 3D printed casts.

Prevalence of burnout and practice-related risk factors among Saudi Board dental residents using the Copenhagen Burnout Inventory: A survey-based cross-sectional study.

Occupational burnout is a chronic psychological problem affecting professionals. The aim of this study was to assess the types and categories of burnout among Saudi Dental board residents at different levels of residency in different provinces of Saudi Arabia, using the Copenhagen Burnout Inventory. Questionnaires were sent to 170 Saudi Dental board residents via Email and WhatsApp. at various training centers in Saudi Arabia, in May 2022. A part of the questionnaire covered the socio-demographic characteristics of the participants such as gender, training level or center, number of working sessions or hours per week and day, dental speciality, and marital status. The second part consisted of the Copenhagen Burnout Inventory survey with 21 questions. Only 110 participants returned the answered questions. The overall significant type of burnout was present in 46.3% of the respondents while 53.7%, were for free or minimal burnout. Personal, work-related, and patient-related burnout recorded 62%/38%; 40% to 60%, and 60%:40% for free or minimal to significant burnout. The overall burnout types of values were equal in both gender as well as training levels with no significant differences and P-values ≤ .05. Burnout values were close to each other among the participants in different specialties, except for orthodontics residents which were the least. Analysis of variance, followed by chi-square tests showed a significant difference among participants in different specialties in type and categories of burnout with P-values between .002 to .029. Finally, the burnout value was higher among married participants. Overall burnout types were marginally similar between genders and training levels, while the significant was slightly higher in females, married, highest training level, restorative, and prosthodontic speciality participants.

Comparative Analysis of Properties in Chairside Silicone Denture Liners versus Heat-Cured Molloplast-B: An In-Depth In Vitro Evaluation.

BACKGROUND We investigated the bond strength, tensile strength, and water absorption properties of 4 widely used chairside silicone long-term denture soft lining materials and compared properties with those of heat-cured silicone material. MATERIAL AND METHODS Four chairside materials (GC Reline Soft, Mucopren Soft, Sofreliner Soft, and Elite Soft Relining) and a heat-cured silicone material (Molloplast B) were investigated. For tensile and shear bond strength and tensile strength, samples were prepared according to the manufacturers' instructions and the testing machine used. For water absorption, IOS 1567 was followed to prepare specimens. Bond strengths were measured using a Lloyd Instruments materials testing machine. Ten specimens for each test were prepared for each soft liner, except for water absorption and solubility tests, for which only 5 specimens were prepared. ANOVA, Bonferroni, and Kruskal-Wallis tests were used to compare values of materials and assess changes over time. RESULTS There was strong evidence of differences in the properties between materials. GC Reline Soft showed comparable tensile bond (1.4±0.6 MPa), shear bond (1.1±0.4 MPa), tensile strength (5.44±0.98), water absorption (0.92±0.2 µg/mm³), and solubility values (0.3±0.2 µg/mm3) to that of Molloplast B (1.4±0.4; 1.6±0.5; 4.53±0.9 MPa, 1.7±0.3, and 1.0±0.3 µg/mm³, respectively). The water solubility of Sofreliner Soft was significantly lower (1.5±0.8 µg/mm³) than that of Molloplast B. CONCLUSIONS There were significant differences between some properties of 4 chairside denture soft lining materials and that of Molloplast B, which had higher shear and tensile bond strength than chairside denture silicone soft lining materials but had the highest water solubility.

Effect of smokeless tobacco on color stability and surface roughness of CAD/CAM milled, 3D printed, and conventional provisional crown and fixed dental prosthesis materials: An in vitro study.

BACKGROUND: Provisional fixed dental prosthesis (FDP) plays an important role during fixed prosthodontic therapy till the definitive. Discoloration of materials used for provisional FDPs can cause patient dissatisfaction and may create doubt about the color stability of the definitive FDP. Surface roughness is the other major property to be taken into consideration for provisional FDP materials. Smokeless tobacco is reported to affect the color stability and surface roughness of different prosthetic materials. OBJECTIVE: The aim of the current study was to evaluate the effect of two types of smokeless tobacco (black and white) on color stability and surface roughness of 3D printed, CAD/CAM milled, and conventional provisional FDP resin materials. METHODS: A total of 144 disc-shaped specimens were fabricated using four techniques CAD/CAM subtractive technique (milling), CAD/CAM additive technique (3D Printing), and conventional technique using autopolymerized PMMA, and autopolymerized Bis-acrylic resins. Each group was subdivided into three subgroups of twelve specimens each, and were submerged into three solutions (artificial salivary substitute, black smokeless tobacco, white smokeless tobacco). The change in color and surface roughness was evaluated and the data collected were statistically analyzed. RESULTS: It was observed that black smokeless tobacco caused the maximum color change and the effect was highest in autopolymerized PMMA resin specimens (ΔE = 9.343 ± 0.489), followed by 3D printed (ΔE = 7.187 ± 0.391), autopolymerized Bis-acryl (ΔE = 6.464 ± 0.453) and milled (ΔE = 4.978 ± 0.227). White smokeless tobacco was found to cause a maximum change in surface roughness and the effect was highest in autopolymerized Bis-acryl specimens (ΔRa = 0.321 ± 0.015 µm), followed by autopolymerized PMMA (ΔRa = 0.297± 0.015 µm), 3D printed (ΔRa = 0.191 ± 0.019 µm), and milled (ΔRa = 0.168 ± 0.014 µm). Statistically significant (p-value < 0.05) differences were observed among all techniques and solutions. CONCLUSIONS: The change in color and surface roughness were maximum in the case of FDPs prepared using autopolymerizing resins, followed by 3D printed, and CAD/CAM milled reins.

Validation of Digital Impressions' Accuracy Obtained Using Intraoral and Extraoral Scanners: A Systematic Review.

BACKGROUND: At present, the evidence regarding digital impressions' accuracy recorded by using digital scanners is lacking. This systematic review aimed to evaluate whether the type of scanning (intraoral/extraoral) affects the Accuracy of Digital Impressions. METHOD: Two independent reviewers performed a systematic search in the database both electronically and manually (PubMed, Ebsco HOST, the Cochrane Library, and Google Scholar) for articles published from 1 January 2010 to 1 December 2022. This study was registered with the International Prospective Register of Systematic Reviews (PROSPERO CRD42020188765) and followed the PRISMA statement. The question in focus was as follows: Does the type of scanning (intraoral or extraoral) affect the accuracy of digital impression? RESULTS: A total of 449 papers were obtained by searching electronically and manually. In total, 15 complete-text papers qualified for assessment based on eligibility criteria. After reading the full-text articles, five studies were excluded. Ten studies were selected for the qualitative analysis. The qualitative data reported that the accuracy of both types of scanners (intraoral and extraoral) lies within the range of clinical acceptability. Nevertheless, the intraoral scanners seem to be more accurate when compared to the extraoral scanners for a partial arch situation. CONCLUSIONS: Scanning type affects the accuracy of the digital impression. Various factors influence the scanning ability. Intraoral scanners seem to be more accurate compared to extraoral scanners for a partial arch situation. More studies comparing the accuracy of the intraoral scanner and extraoral scanner for a complete arch scan and in an in vivo study setting are needed.

Influence of different surface treatment on bonding of metal and ceramic Orthodontic Brackets to CAD-CAM all ceramic materials.

BACKGROUND: Developing efficient bonding techniques for orthodontic brackets and all-ceramic materials continues to pose a clinical difficulty. This study aimed to evaluate the shear bond strengths (SBS) of metal and ceramic brackets to various all-ceramic CAD-CAM materials, such as lithium disilicate CAD (LDS-CAD), polymer-infiltrated ceramic (PIC), zirconia-reinforced lithium silicate glass ceramic (ZLS), and 5YTZP zirconia after different surface treatments and thermal cycling. MATERIALS AND METHODS: The samples were divided into two groups to be bonded with ceramic and metal lower incisor brackets. Each group was subdivided into a control group devoid of any surface treatment, 10% HF acid (HFA) etching, ceramic etch & prime (MEP), Al2O3 air abrasion, and medium grit diamond bur roughening. After surface treatment, brackets were bonded with composite resin cement, thermal cycled, and tested for shear bond strength. The failed surfaces were evaluated with a digital microscope to analyse the type of failure. The data were statistically analysed using a one-way ANOVA and Tukey HSD tests at p < 0.05. RESULTS: The highest mean bond strengths were found with HFA etching in LDS-CAD (13.17 ± 0.26 MPa) and ZLS (12.85 0.52 MPa). Diamond bur recorded the lowest mean bond strength roughening across all the ceramic groups. There were significant differences in mean shear bond values per surface treatment (p < 0.001) and ceramic materials. CONCLUSION: Among the surface treatment protocols evaluated, HFA etching and MEP surface treatment resulted in enhanced bond strength of both ceramic and metal brackets to CAD-CAM all ceramic materials.

Unlocking Endocrown Restoration Expertise Among Dentists: Insights from a Multi-Center Cross-Sectional Study.

BACKGROUND This study, employing an online questionnaire, aimed to assess and contrast the awareness, knowledge, and perceptions of dentists in Saudi Arabia (SA) regarding endocrowns (EC) as post-endodontic restorations with those of dentists educated in various other countries. MATERIAL AND METHODS We conducted a cross-sectional survey among dental interns and practicing dentists in government facilities, private dental centers, and dental colleges in SA, including participants of diverse nationalities. We disseminated validated, closed-ended questionnaires through WhatsApp via Google Forms. The Chi-square test was applied to assess associations between categorical variables, with a P-value of ≤0.05 indicating statistical significance. RESULTS The majority of participants (61.2%) indicated that EC restorations are best suited for molar teeth. Furthermore, 69.6% asserted that the primary objective of employing EC is to accomplish minimally invasive preparations while preserving the existing tooth structure. Among the responses, 68.3% pinpointed debonding of ECs as a significant cause of failure. Notably, substantial differences were observed in responses concerning the knowledge or practice of EC across various factors such as gender, educational attainment, country of graduation, and workplace. CONCLUSIONS The findings reveal a comparatively low adoption of ECs among the participants, irrespective of experience or country of education. This underscores the need for incorporating ECs into dental curricula through theoretical and clinical discussions or considering them as a subject for post-graduate continuing education programs.

Antibacterial Efficacy and Surface Characteristics of Boron Nitride Coated Dental Implant: An In-Vitro Study.

This in vitro study evaluated bacterial cell proliferation and biofilm adhesion on titanium discs with and without antibacterial surface treatment to reduce the chances of peri-implant infections. Hexagonal boron nitride with 99.5% purity was converted to hexagonal boron nitride nanosheets via the liquid phase exfoliation process. The spin coating method was used for uniform coating of h-BNNSs over titanium alloy (Ti6Al4V) discs. Two groups of titanium discs were formed: Group I (n = 10) BN-coated titanium discs and Group II (n = 10) uncoated titanium discs. Two bacterial strains, Streptococcus mutans (initial colonizers) and Fusobacterium nucleatum (secondary colonizers), were used. A zone of inhibition test, microbial colony forming units assay, and crystal violet staining assay were used to evaluate bacterial cell viability. Surface characteristics and antimicrobial efficacy were examined by scanning electron microscopy with energy dispersion X-ray spectroscopy. SPSS (Statistical Package for Social Sciences) version 21.0 was used to analyze the results. The data were analyzed for probability distribution using the Kolmogorov-Smirnov test, and a non-parametric test of significance was applied. An inter-group comparison was done using the Mann-Whitney U test. A statistically significant increase was observed in the bactericidal action of BN-coated discs compared to uncoated discs against S. mutans, but no statistically significant difference was found against F. nucleatum.

A Rat Model of Rheumatoid Arthritis: TDZD-8 is Associated with the Protection Against the Induction of the Synovium Knee Joint IL-17A/GSK3β/ROS/α-SMA Axis of Fibrosis

SUMMARY: Rheumatoid arthritis (RA) that affects the synovial knee joint causes swelling of the synovial membrane and tissue damage. Interleukin-17A (IL-17A) and the enzyme glycogen synthase kinase-3β (GSK3β) are involved in the pathogenesis of RA. The link between IL-17A, GSK3β, the oxidative stress, and the profibrogenic marker alpha-smooth muscle actin (α-SMA) with and without TDZD-8, GSK3β inhibitor has not been studied before. Consequently, active immunization of rats was performed to induce RA after three weeks using collagen type II (COII) injections. The treated group received daily injection of 1 mg/kg TDZD-8 for 21 days following the immunization protocol (COII+TDZD-8). Blood and synovium tissue samples were harvested at the end of the experiment. RA development was confirmed as corroborated by a substantial increase in blood levels of the highly specific autoantibody for RA, anti-citrullinated protein antibody as well as augmentation of reactive oxidative species (ROS) levels measured as lipid peroxidation. RA induction also increased synovium tissue levels of IL-17A and the profibrogenic marker, α-SMA. All these parameters seemed to be significantly (p<0.0001) ameliorated by TDZD-8. Additionally, a significant correlation between IL-17A, ROS, and α-SMA and biomarkers of RA was observed. Thus, knee joint synovium RA induction augmented IL-17A/GSK3β/ROS/α-SMA axis mediated arthritis in a rat model of RA, which was inhibited by TDZD-8.

La artritis reumatoide (AR) que afecta la articulación sinovial de la rodilla provoca inflamación de la membrana sinovial y daño tisular. La interleucina-17A (IL-17A) y la enzima glucógeno sintasa quinasa-3β (GSK3β) están involucradas en la patogenia de la AR. No se ha estudiadol vínculo entre IL-17A, GSK3β, el estrés oxidativo y el marcador profibrogénico actina de músculo liso alfa (α-SMA) con y sin inhibidor de TDZD-8, GSK3β. En consecuencia, se realizó una inmunización activa de ratas para inducir la AR después de tres semanas usando inyecciones de colágeno tipo II (COII). El grupo tratado recibió una inyección diaria de 1 µg/ kg de TDZD-8 durante 21 días siguiendo el protocolo de inmunización (COII+TDZD-8). Se recogieron muestras de sangre y tejido sinovial al final del experimento. El desarrollo de AR se confirmó como lo corroboró el aumento sustancial en los niveles sanguíneos del autoanticuerpo altamente específico para AR, el anticuerpo antiproteína citrulinada, así como el aumento de los niveles de especies oxidativas reactivas (ROS) medidos como peroxidación lipídica. La inducción de AR también aumentó los niveles de tejido sinovial de IL-17A y el marcador profibrogénico, α-SMA. Todos estos parámetros parecían mejorar significativamente (p<0,0001) con TDZD-8. Además, se observó una correlación significativa entre IL- 17A, ROS y α-SMA y biomarcadores de AR. Por lo tanto, la inducción de AR en la sinovial de la articulación de la rodilla aumentó la artritis mediada por el eje IL-17A/GSK3β/ROS/α-SMA en un modelo de rata de AR, que fue inhibida por TDZD-8.

A rat model of rheumatoid arthritis: TDZD-8 is associated with the protection against the induction of the synovium knee joint IL-17A/GSK3beta/ROS/alpha-SMA axis of fibrosis / Un modelo de rata de artritis reumatoide: TDZD-8 está asociado con la protección contra la inducción del eje de fibrosis de la articulación sinovial de la rodilla IL-17A/GSK3ß/ROS/α-SMA

SUMMARY: Rheumatoid arthritis (RA) that affects the synovial knee joint causes swelling of the synovial membrane and tissue damage. Interleukin-17A (IL-17A) and the enzyme glycogen synthase kinase-3β (GSK3β) are involved in the pathogenesis of RA. The link between IL-17A, GSK3β, the oxidative stress, and the profibrogenic marker alpha-smooth muscle actin (α-SMA) with and without TDZD-8, GSK3β inhibitor has not been studied before. Consequently, active immunization of rats was performed to induce RA after three weeks using collagen type II (COII) injections. The treated group received daily injection of 1 mg/kg TDZD-8 for 21 days following the immunization protocol (COII+TDZD-8). Blood and synovium tissue samples were harvested at the end of the experiment. RA development was confirmed as corroborated by a substantial increase in blood levels of the highly specific autoantibody for RA, anti-citrullinated protein antibody as well as augmentation of reactive oxidative species (ROS) levels measured as lipid peroxidation. RA induction also increased synovium tissue levels of IL-17A and the profibrogenic marker, α-SMA. All these parameters seemed to be significantly (p<0.0001) ameliorated by TDZD-8. Additionally, a significant correlation between IL-17A, ROS, and α-SMA and biomarkers of RA was observed. Thus, knee joint synovium RA induction augmented IL-17A/GSK3β/ROS/α-SMA axis mediated arthritis in a rat model of RA, which was inhibited by TDZD-8.

La artritis reumatoide (AR) que afecta la articulación sinovial de la rodilla provoca inflamación de la membrana sinovial y daño tisular. La interleucina-17A (IL-17A) y la enzima glucógeno sintasa quinasa-3β (GSK3β) están involucradas en la patogenia de la AR. No se ha estudiadol vínculo entre IL-17A, GSK3β, el estrés oxidativo y el marcador profibrogénico actina de músculo liso alfa (α-SMA) con y sin inhibidor de TDZD-8, GSK3β. En consecuencia, se realizó una inmunización activa de ratas para inducir la AR después de tres semanas usando inyecciones de colágeno tipo II (COII). El grupo tratado recibió una inyección diaria de 1 µg/ kg de TDZD-8 durante 21 días siguiendo el protocolo de inmunización (COII+TDZD-8). Se recogieron muestras de sangre y tejido sinovial al final del experimento. El desarrollo de AR se confirmó como lo corroboró el aumento sustancial en los niveles sanguíneos del autoanticuerpo altamente específico para AR, el anticuerpo antiproteína citrulinada, así como el aumento de los niveles de especies oxidativas reactivas (ROS) medidos como peroxidación lipídica. La inducción de AR también aumentó los niveles de tejido sinovial de IL-17A y el marcador profibrogénico, α-SMA. Todos estos parámetros parecían mejorar significativamente (p<0,0001) con TDZD-8. Además, se observó una correlación significativa entre IL- 17A, ROS y α-SMA y biomarcadores de AR. Por lo tanto, la inducción de AR en la sinovial de la articulación de la rodilla aumentó la artritis mediada por el eje IL-17A/GSK3β/ROS/α-SMA en un modelo de rata de AR, que fue inhibida por TDZD-8.

Radiographic Evaluation of the Gap between Cemented Post and Remaining Gutta-Percha in Endodontically Treated Teeth Performed by Undergraduate Students: A Retrospective Cross-Sectional Study.

The coronal seal in root canal-treated teeth may be compromised depending on the accuracy of post space preparation and post cementation along with remaining gutta-percha. Root canal treatment can be compromised by endotoxins released by the coronal bacteria as a result of microleakage. The study was conducted by undergraduate students to measure the gap between the cemented post and residual gutta-percha. In total, 217 endodontically treated teeth were evaluated with intraoral peri-apical radiographs. Based on the intraoral periapical radiographic examination in the CS-R4 program, Group I had no gap, Group II had a gap of >0 to 2 mm, and Group III had a gap of more than 2 mm between the end of the cemented post and the remaining gutta-percha. In total, 40% (n = 87) of the teeth had no gap, 59% (127) had a gap of >0 to 2 mm, and 1% (n = 3) had a gap of more than 2 mm between the cemented post end and remaining gutta. Chi square test revealed a significant difference in the gap between the post and remaining gutta-percha between males and females students (p < 0.001). In terms of the gap between the cemented post end and the residual gutta-percha, the root canal treated teeth with post and core by undergraduates were clinically acceptable.

Metformin Suppresses Thioacetamide-Induced Chronic Kidney Disease in Association with the Upregulation of AMPK and Downregulation of Oxidative Stress and Inflammation as Well as Dyslipidemia and Hypertension.

Toxic chemicals such as carbon tetrachloride and thioacetamide (TAA) are reported to induce hepato-nephrotoxicity. The potential protective outcome of the antidiabetic and pleiotropic drug metformin against TAA-induced chronic kidney disease in association with the modulation of AMP-activated protein kinase (AMPK), oxidative stress, inflammation, dyslipidemia, and systemic hypertension has not been investigated before. Therefore, 200 mg/kg TAA was injected (via the intraperitoneal route) in a model group of rats twice a week starting at week 3 for 8 weeks. The control rats were injected with the vehicle for the same period. The metformin-treated group received 200 mg/kg metformin daily for 10 weeks, beginning week 1, and received TAA injections with dosage and timing similar to those of the model group. All rats were culled at week 10. It was observed that TAA induced substantial renal injury, as demonstrated by significant kidney tissue damage and fibrosis, as well as augmented blood and kidney tissue levels of urea, creatinine, inflammation, oxidative stress, dyslipidemia, tissue inhibitor of metalloproteinases-1 (TIMP-1), and hypertension. TAA nephrotoxicity substantially inhibited the renal expression of phosphorylated AMPK. All these markers were significantly protected by metformin administration. In addition, a link between kidney fibrosis and these parameters was observed. Thus, metformin provides profound protection against TAA-induced kidney damage and fibrosis associated with the augmentation of the tissue protective enzyme AMPK and inhibition of oxidative stress, inflammation, the profibrogenic gene TIMP-1, dyslipidemia, and hypertension for a period of 10 weeks in rats.

Online Questionnaire-Based Study to Evaluate the Attitudes and Use of Rubber Dental Dams by Saudi Dental Practitioners.

BACKGROUND A dental dam is a protective sheet with an aperture and is used to prevent the spread of infection during dental procedures. This study aimed to use a 2-part online questionnaire to evaluate the attitudes and use of rubber dental dams by 300 Saudi dental interns, general dental practitioners, residents, specialists, and consultants in prosthodontics, endodontics, and restorative dentistry. MATERIAL AND METHODS The 17-item validated questionnaire consisted of 5 questions on demographics, 2 on knowledge, 6 on attitudes, and 4 on perceptions. It was distributed through Google Forms. The chi-square test was used to determine the associations between the study variables and perception questions. RESULTS A total of 41.67% participants were specialists/consultants, among which 59.2% were in the prosthodontics specialty, 12.8% in endodontics, and 28% in restorative dentistry. Most participants (84.67%) stated the necessity of using rubber dams during post and core procedures. A total of 53.67% had received enough training for using rubber dams during their undergraduate/residency education. The majority of participants (41%) also preferred using rubber dams during the prefabricated post and core procedures, and 28.33% stated that the remaining tooth structure was one of the major reasons for not using rubber dams during the post and core procedures. CONCLUSIONS Workshops and hands-on training should be conducted among dental graduates to instill a positive attitude regarding the use of rubber dams.

Lower Extremity Arterial Disease in Type 2 Diabetes Mellitus: Metformin Inhibits Femoral Artery Ultrastructural Alterations as well as Vascular Tissue Levels of AGEs/ET-1 Axis-Mediated Inflammation and Modulation of Vascular iNOS and eNOS Expression.

Lower extremity arterial disease (LEAD) is a major risk factor for amputation in diabetic patients. The advanced glycation end products (AGEs)/endothelin-1 (ET-1)/nitric oxide synthase (NOS) axis-mediated femoral artery injury with and without metformin has not been previously investigated. Type 2 diabetes mellitus (T2DM) was established in rats, with another group of rats treated for two weeks with 200 mg/kg metformin, before being induced with T2DM. The latter cohort were continued on metformin until they were sacrificed at week 12. Femoral artery injury was established in the diabetic group as demonstrated by substantial alterations to the femoral artery ultrastructure, which importantly were ameliorated by metformin. In addition, diabetes caused a significant (p < 0.0001) upregulation of vascular tissue levels of AGEs, ET-1, and iNOS, as well as high blood levels of glycated haemoglobin, TNF-α, and dyslipidemia. All of these parameters were also significantly inhibited by metformin. Moreover, metformin treatment augmented arterial eNOS expression which had been inhibited by diabetes progression. Furthermore, a significant correlation was observed between femoral artery endothelial tissue damage and glycemia, AGEs, ET-1, TNF-α, and dyslipidemia. Thus, in a rat model of T2DM-induced LEAD, an association between femoral artery tissue damage and the AGEs/ET-1/inflammation/NOS/dyslipidemia axis was demonstrated, with metformin treatment demonstrating beneficial vascular protective effects.

Effects of Smokeless Tobacco on Color Stability and Surface Roughness of 3D-Printed, CAD/CAM-Milled, and Conventional Denture Base Materials: An In Vitro Study.

Tobacco consumption in its different forms can affect the optical and surface properties of dental materials that are used in the oral cavity. Thus, the present study was conducted to evaluate the effects of two commercially available smokeless tobacco products on the color stability and surface roughness of denture base resins that were fabricated using three different techniques (CAD/CAM milling, 3D printing, and conventional heat polymerization). A total of 126 denture base resin specimens were fabricated using the three different manufacturing techniques (n = 42 each). Specimens from each group were further subdivided into three subgroups (n = 14 each) and immersed in three different immersion media (a khaini suspension, a tabbaq suspension, and artificial saliva). The differences in color and surface roughness were assessed according to data that were collected and statistically analyzed using SPSS version 24.0. The tabbaq smokeless tobacco was found to cause greatest changes in color and surface roughness; the effect was observed to be highest in the 3D-printed specimens followed by the conventional heat-polymerized and CAD/CAM milled specimens. The mean changes in color and surface roughness were the highest for the tabbaq smokeless tobacco followed by the khaini smokeless tobacco and the artificial saliva. Statistically significant (p-value < 0.05) differences were observed among all techniques and suspensions. We concluded that the mean changes in color and surface roughness were significantly higher for the 3D-printed dentures compared to the conventional heat-polymerized and CAD/CAM-milled dentures. Thus, the results of the present study strengthened the concept that tobacco in any form can lead to changes in the color and surface roughness of denture base materials.

Dimensional Stability of Light-Activated Urethane Dimethacrylate Denture Base Resins.

An accurate and dimensionally stable trial denture base is required for a successful denture. The aim of this in vitro study was to assess the dimensional stability of a light-activated urethane dimethacrylate (UDMA) visible light cure (VLC) denture base with three fabrication techniques and different curing cycles. Forty-five VLC denture base samples were divided evenly into three groups. Group A used a conventional fabrication technique with a curing cycle of 5 min. Group B used a modified fabrication technique with two 4-min curing cycles. Group C used a multi-step fabrication technique with three curing cycles (4 min, plus 4 min, plus 2 min). The samples were sectioned and observed under a stereomicroscope to measure the discrepancy between the sample and the master cast. The mean dimensional discrepancy (mm) at the molar region at mid-palate, after 24 h in Group A, B and C was 0.790 mm, 0.741 mm and 0.379 mm, respectively; at the right ridge crest, it was 0.567, 0.408 and 0.185, while at the left ridge crest it was 0.475, 0.331 and 0.125, respectively. Statistical analysis showed significantly different dimensional discrepancies among the groups at all three sites; right ridge crest (F = 93.54, p < 0.001), left ridge crest (F = 105.96, p < 0.001) and mid-palate (F = 125.53, p < 0.001). Within the limitations of this laboratory study, it can be concluded that the denture base using a multi-step fabrication technique with three curing cycles provides better adaptation than the conventional technique. The significance of the study is that clinicians should consider performing denture base fabrication using a multi-step technique to enhance adaptation and hence the stability of the dentures for patients.

Retentive Forces and Deformation of Fitting Surface in RPD Clasp Made of Polyether-Ether-Ketone (PEEK).

BACKGROUND: Polyetheretherketone (PEEK) has provided the option to fabricate RPDs with aesthetics unlike metal RPDs, but little attention has been paid to its suitability, especially towards the retentive forces and deformation of the clasp. This study aimed to examine the retentive forces and the fitting surface (inner surface) deformation of clasps made from PEEK and compare it with cobalt-chromium (Co-Cr) clasp. METHODS: Forty-two circumferential clasps (14 Co-Cr and 28 PEEK) were fabricated and divided into two groups with clasp undercuts (0.25 mm and 0.5 mm) with thicknesses of 1 mm and 1.5 mm. Each was examined for retentive forces after cycle test on its abutment for 360 cycles. Initial and final retentive forces were recorded. The fitting surface deformation was determined using 3-Matic research analysis software. RESULTS: The results revealed that highest mean initial retentive force was of Co-Cr clasps with 0.50 mm undercut 22.26 N (±10.15 N), and the lowest was the 1 mm PEEK clasps with 0.25 mm undercut 3.35 N (±0.72 N) and highest mean final retentive force was the Co-Cr clasps with 0.50 mm undercut 21.40 N (±9.66 N), and the lowest was the 1 mm PEEK clasps with 0.25 mm undercut 2.71 N (±0.47 N). PEEK clasps had a lower retentive force than Co-Cr clasps with 0.50 undercut. PEEK clasps (1.5 mm) at 0.25 mm undercut had the least deformation (35.3 µm). PEEK showed significantly less deformation (p ≤ 0.014) than Co-Cr. CONCLUSION: The deformation of PEEK clasps fitting surface was lower than Co-Cr clasps and retentive forces were close to the Co-Cr clasps, suggesting the use of PEEK as an aesthetic clasp option for RPD framework.

Quercetin and resveratrol are associated with the downregulation of TNFalpha/NF-kB/inos axis-mediated acute liver injury in rats induced by paracetamol poisoning / La quercetina y el resveratrol están asociados con la regulación decreciente de la lesión hepática aguda mediada por el eje TNF-alfa/NF-kB/inos en ratas inducida por envenenamiento con paracetamol

SUMMARY: Paracetamol (known as acetaminophen, or APAP) poisoning causes acute liver damage that can lead to organ failure and death. We sought to determine that APAP overdose can augment tumor necrosis factor-alpha (TNF-α)/ nuclear factor kappa B (NF-kB)/induced nitic oxide synthase (iNOS) axis-mediated hepatotoxicity in rats, and the anti-inflammatory polyphenolic compounds, quercetin (QUR) plus resveratrol (RES) can ameliorate these parameters. Therefore, we induced acute hepatotoxicity in rats using APAP overdose (2 g/kg, orally) and the protective group of rats were treated with 50 mg/kg QUR plus 30 mg/kg RES for one week before APAP ingestion. Animals were killed at day 8. APAP poisoning caused the induction of hepatic tissue levels of TNF-α, NF-kB, and iNOS, which were significantly (p<0.05) decreased by QUR+RES. QUR+RES, also inhibited liver injury biomarkers, alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Additionally, a link between liver injury and TNF-α /NF-kB / iNOS axis mediated hepatotoxicity was observed. Thus, the presented data backing the conclusion that intoxication by paracetamol increases TNF-α / NF-kB / iNOS axis -mediated hepatotoxicity, and is protected by a combination of quercetin and resveratrol.

El envenenamiento por paracetamol (conocido como acetaminofeno o APAP) causa daño hepático agudo que puede provocar una insuficiencia orgánica y la muerte. El objetivo de este trabajo fue determinar si la sobredosis de APAP puede aumentar la hepatotoxicidad mediada por el eje del factor de necrosis tumoral alfa (TNF-α)/factor nuclear kappa B (NF-kB)/óxido nítico sintasa inducida (iNOS) en ratas, y si el polifenólico antiinflamatorio compuesto por quercetina (QUR) más resveratrol (RES) pueden mejorar estos parámetros. Por lo tanto, inducimos hepatotoxicidad aguda en ratas usando una sobredosis de APAP (2 g/kg, por vía oral). El grupo protector de ratas se trató con 50 mg/ kg de QUR más 30 mg/kg de RES durante una semana antes de la ingestión de APAP. Los animales se sacrificaron el día 8. El envenenamiento con APAP en el tejido hepático provocó la inducción de niveles de TNF-α, NF-kB e iNOS, que se redujeron significativamente (p<0,05) con QUR+RES. QUR+RES, también inhibió los biomarcadores de daño hepático, la alanina aminotransferasa (ALT) y el aspartato aminotransferasa (AST). Además, se observó una relación entre la lesión hepática y la hepatotoxicidad mediada por el eje TNF-α /NF-kB/iNOS. Por lo tanto, los datos presentados respaldan la conclusión de que la intoxicación por paracetamol aumenta la hepatotoxicidad mediada por el eje TNF-α /NF-kB / iNOS, y está protegida por una combinación de quercetina y resveratrol.