Additive manufacturing technologies can be used to fabricate 3D-printed dental restorations. In this study, we evaluated the effectiveness of the functionalized loading of zirconium dioxide (ZrO₂) nanoparticles and silver-nanoparticles-immobilized halloysite (HNC/Ag) nanotubes into 3D printing resins. We created 3D printing resins by adding different mass fractions of ZrO₂ and HNC/Ag. First, six groups of samples containing ZrO₂ were prepared, comprising five groups with different mass fractions and one control group of ZrO₂ containing 1 to 16 %wt. Different mass fractions of HNC/Ag fillers were combined with the ZrO₂ mixture and resin at the ideal ratio from 1 to 7.5 %wt. The mechanical characteristics of 3D resin that we assessed were the flexural strength, flexural modulus, fracture toughness, and the microhardness. Additional rates of ZrO₂ 4 %wt. and HNC/Ag 5 %wt. significantly increase the flexural strength, flexural modulus, and fracture toughness compared to the control group (p < 0.001). ZrO₂ 16 %wt. and HNC/Ag 5 %wt. were found to be significantly harder compared to the other groups (p < 0.001). The amounts of NPs that can be added to 3D printing resin modification appears to be 4 %wt., and HNC/Ag 5 %wt. can be advantageous in terms of fracture toughness, flexural strength, and flexural modulus. All additions of nanoparticles raised the resin’s hardness.

Background: Ceramic restorations are widely used nowadays as the esthetic demand has increased in the worldwide population, and lithium disilicate and feldspathic porcelain materials are the most widely used veneer materials. The traditional removal procedure for veneers was recently replaced with the use of laser technology to debond the veneers so that the de-bonded veneers can be preserved and re-used. Aim: Up to now, there have been few studies regarding using lasers to remove ceramic laminate; thus, it is clear why this research topic is important for examining the efficiency of lasers in the use of de-bonding for different ceramic laminates with varying compositions and materials. Materials and Methods: This study employed forty-five normal human maxillary first premolars with comparable proportions. The forty-five teeth were initially split into three groups of fifteen teeth, and the teeth were chosen at random. Each group fused pairs of various ceramic materials. A total of fifteen teeth in the first group underwent feldspathic porcelain restorations. The second group contained fifteen restorations made of lithium disilicate glass-ceramic CAD-CAM. In the third group, fifteen teeth were restored using glass-ceramic that had a lithium disilicate glass-ceramic ingot. The RelyX Veneer A1 shade, available from 3M EPSE in the United States, was used to bond all the samples. The specimens were then submerged for approximately 24 h in distilled water at 37 degrees Celsius in order to simulate the conditions in an oral cavity. An Er,Cr: YSGG laser (Waterlase, iPlus, Biolase, from USA) was used with a turbo headpiece and an MX7 sapphire tip for irradiation. Results: The time needed for the ceramic disc to debond was calculated using a digital stopwatch. The average removal times for the feldspathic porcelain, lithium disilicate glass-ceramic ingot, and lithium disilicate glass-ceramic CAD-CAM were 10.067 ± 1.668 s, 5.200 ± 1.146 s, and 5.133 ± 1.125 s, while the removal times ranged from 8–12 s, 4–7 s, and 4–7 s, respectively. Compared to the other ceramic materials, de-bonding the feldspathic porcelain took longer. Conclusions: According to this study, the Er,Cr: YSGG laser application using the same study parameters made it simpler to de-bond lithium disilicate and feldspathic porcelain. Lithium disilicate, as opposed to feldspathic porcelain, transmits laser light more effectively; hence, the results varied depending on the materials, and the debonding occurred primarily at the veneer–cement interface.

Background and objectives: Dental veneers are constructed from different materials such as porcelain, pressed ceramic, processed composite, or directly applied composite. The purpose of this study was to ascertain the preferred dental materials for veneers and the knowledge about its procedures by dentists in the Kurdistan region/Erbil city Methods: To assess general dentists' knowledge and practical use of direct and indirect veneers, a cross-sectional survey was undertaken in March 2022 among all general dentists and different dental specialties in Erbil city. The questionnaire was composed of 16 questions and was organized into knowledge, attitude, and practice sections. Google forms were used to collect responses, which were then statistically examined. Results: This study revealed respondents were having difficulty in veneer cementations followed by tooth preparations, P value=0.025, hence statistically significant. The most popular veneer among practitioners were EMAX press and EMAX CAD. In addition, veneer dislodgement was the most common problem faced by dentists followed by tooth sensitivity, p value 0.012 so statistically significant. Conclusions: Given the study's limitations, it may be stated that dentists should get good expertise in case selection for veneers, shade matching, optimal preparation processes and designs, and current advancements in veneer materials and adhesive techniques.

Introduction: Quorum Sensing (QS) is a mechanism many bacteria use to manage their cooperative activities and physiological functions. The Fsr system in Enterococcus faecalis (ATCC 29,212) is an example of quorum sensing with a cell density-dependent two-component regulatory system mechanism. Several publications have shown that the Fsr system and proteases independently contribute to E. faecalis pathogenicity in various infection models. Objectives: There is currently no published research to determine the exact molecular ability of Salvadora persica on quorum-sensing genes. Therefore, this study aimed to determine the plant extracts that inhibit the expression of the quorum-sensing gene (FsrC). Methods: Different fractions of Salvadora persica were obtained using different solvents, including standard hexane, chloroform, ethyl acetate, n-butanol, ethyl alcohol, and water which are expressed as fractions 1,2,3,4,5 and 6, respectively. Antibacterial activity assay of different plant extracts (S. persica) was determined by minimum inhibitory concentration (MIC). Finally, the relative expression of the quorum-sensing (QS) gene was evaluated using a One-step quantitative RT-PCR PrimeScript™ RT-PCR Kit. Results: All fractions of S. persica showed antimicrobial activity. However, ethyl acetate- S. persica inhibited the growth of E. faecalis (ATCC 29,212) at the lowest concentration, which was 20mg/ml and the highest concentration inhibited the growth of E. faecalis (ATCC 29,212) was 60mg/ml (chloroform- S. persica). Furthermore, the highest change fold value of (4.99) was recorded in treated E. faecalis (ATCC 29,212) with fraction 1 (hexane). Conclusion: Overall, S. persica showed antimicrobial activity against E. faecalis (ATCC 29,212). However, more studies are required to investigate the effect of different plant extracts on quorum-sensing genes of Enterococcus faecalis.

Failure of endodontic treatment is closely associated with bacterial infection, the study aimed to evaluate the antibacterial properties of MTA- Fillapex and BIO-C against two bacterial species Enterococcus faecalis (E. faecalis) and Staphylococcus aureus (S. aureus). In this in vitro study, two endodontic sealers were used to evaluate antibacterial properties by using an agar diffusion test (ADT) and direct contact test (DCT). The width of the growth inhibition zone after 24 hours was reported in (ADT) as the endodontic sealers' effectiveness. In DCT, the survival of microorganisms was assessed at various periods following the exposure of the bacterial suspension to the sealers for (20 and 40 min) at (1 day, 7 days and 14 days). Colony-forming unit (CFU) counts were made. In ADT, the zones of microbial growth inhibition in BIO-C sealer caused by E. Facealis were relatively larger than that created due to S. Auerous bacteria with mean 0.781 mm and 0.538 mm respectively. Thus, this difference turned out to be significant (p 0.05). In terms of sealers, BIO-C had the most potent antimicrobial properties. It showed significant inhibition against both E.faecalis and S. Auerous on day 1 and the first week of contact times tested. Moreover both BIO-C and MTA Fillapex sealers perform worthy antibacterial activity up to 1 week and BIO-C sealers show better antibacterial efficacy against E. faecalis than MTA Fillapex sealers.

Background/Objectives: Composite resins are widely used restorative materials, but their surface properties may be altered by bleaching procedures. This study aimed to compare the effects of two bleaching techniques—light-activated (zoom) and diode laser-activated—on the surface roughness of nanohybrid and microhybrid composites using Atomic Force Microscopy (AFM) for topographic evaluation. Methods: A total of 60 composite resin disks were fabricated, with 30 nanohybrid and 30 microhybrid samples. Each type was divided into three subgroups: control, zoom bleaching, and laser bleaching (n = 10 per group). Zoom bleaching employed 40% hydrogen peroxide gel activated by the Philips Zoom system, while laser bleaching used a 940 nm diode laser (QuickLase, Kent, UK) in combination with QuickLase bleaching gel containing approximately 35–40% hydrogen peroxide. Surface roughness parameters (Sa) were measured using AFM, and statistical analysis was performed. Results: Both bleaching protocols increased surface roughness compared to controls. Microhybrid composites showed higher roughness after zoom (103.12 ± 19.25 nm) and laser bleaching (106.16 ± 25.21 nm), while nanohybrid composites had lower values after zoom (57.77 ± 13.88 nm) and laser bleaching (78.13 ± 23.29 nm). Significant differences were found between composite types post-bleaching (p < 0.001 for zoom; p = 0.019 for laser). However, differences between bleaching methods within the same composite type were not significant (p > 0.05). Conclusions: Both zoom and laser bleaching negatively affect composite surfaces, with laser bleaching showing a greater impact. Nanohybrid composites demonstrated superior resistance to surface alteration, suggesting better clinical durability. These findings are relevant for clinicians when planning restorative treatments in patients likely to undergo bleaching.