Tikrit Journal for Dental Sciences

Purpose: The aim of this study was to investigate the bond strength of cobalt-chromium (Co-Cr) metal frameworks prepared with three different production techniques with dental porcelain. Methods: In this study, a total of thirty disc samples divided to Three groups (n = 10/group) of metal cylinders (10 mm diameter x 4mm thickness with ring base (12 mm diameter x 1mm thickness) were fabricated by casting (Co–Cr), CAD CAM milling blank(Co–Cr) and by selective laser sintering SLM (Co–Cr) and abraded with airborne-particles then feldespathic porcelain was applied for all discs (10mm diameter x 2mm thickness), before the shear bond strength (SBS) test, the Surface characteristics of the dental alloys were observed by scanning electron microscopy (SEM) to determine the thickness of the oxide layer then surface roughness tester using TR220 portable roughness tester The average surface roughness (Ra) was determined for each group. SBS test-values and failure modes were recorded. Data were analyzed using ANOVA, Tukey’s HSD (a = 0.05). Result: no statistically significant difference of the metal-ceramic bond strength of the test roughness used between casting, milling, and laser no statistically significant difference of the metal-ceramic bond strength of the SBS test between casting compare with milling, and laser groups SBS test statistically significant difference of the metal-ceramic bond strength of the test between milling, and laser technique. The mode of failure shows was mainly cohesive and mixed for all specimens. Conclusion: Within the scope of this research, the CAD/CAM milling Co-Cr alloy has a shear bond strength comparable to the castable alloy. For metal-ceramic restorations, the CAD/CAM milling Co-Cr alloy is an alternative to the castable alloy. Co-Cr restorations can benefit from CAD/CAM manufacture.

Background: Outbreak pneumonia announced in Wuhan, China, in December 2019, had its causative factor classified as a new coronavirus (SARS-CoV-2). Since saliva can host several viruses including SARS-CoV-2, the transmission chance of viruses through saliva, particularly those causing respiratory infections, is unavoidable. COVID-19 can be detected through salivary diagnostic testing which has lots of advantages for medical care professionals and patients. However, the utility of saliva in diagnosing COVID-19 infection remains understudied. Aim of the study: In this review, we attempt to provide a comprehensive and updated source of information about salivary markers of liver enzyme, cytokines and oxidative stress in associated with the infections caused by COVID-19 and the various effects it has had on the dental profession and patients visits to dental clinics. Methods: A systematic search was conducted in PubMed/Medline, EMBASE, and Google Scholar, Scopus, and Web of Science, and Google Scholar from December 1, 2020, till April 15, 2021. Results: Nine studies were included in this study. Pooled results showed a significant increase in salivary liver enzymes (ALT, AST, ALP, GGT among patients with Covid‐19. Three studies showed a significant elevations in salivary TNF-α, CRP, IL‐6 and,IL-10 levels among patients with Covid‐19. Four studies that reported a significant in elevation salivary level of MDA, whereas reduction salivary levels of SOD, catalase, GPX. Conclusion: Our meta-analysis shows that deranged of salivary liver enzymes , hyper-inflammation, may indicate severe COVID-19 and could also predict mortality. Larger studies are needed to evaluate the relationship between derangement in salivary biochemical and mortality in COVID-19.

Invisalign is Elastic thermoplastic material is used in orthodontic devices to apply pressure to the teeth, causing them to slide into the aligner's position. When compared to typically fixed appliances for mild to severe malocclusion, these devices are more attractive, efficient, and comfortable. Clear aligners provide significant advantages, especially for adult patients, but they also have some disadvantages.

The purpose of this study is to look into the effects of calcium hydroxide and theracal the degree of polymerization of a dual cure liner, as well as pH at various times. Materials and procedures • The liner was made up of forty discs of the tested materials (resin modified calcium silicate and calcium hydroxide pulp capping). Each tested material was separated into two subgroups according to the test to be done (each subgroup n=10) and tested. Cylinders of 8mm diameter and 2mm thickness were photoactivated for 15 seconds and then divided into two groups according to their type. Dgree of conversion A Fourier-transform infrared spectrometer with a high conversion degree was used. By putting a 1 mm-thick sample on the crystal and light curing it for 20 seconds, the time DC of Theracal and dycal were determined. The activated light had a wavelength of 450–490nm and a power density of 1,500 mW/cm2. Theracal and calcium hydroxide (dycal) degrees of conversion (DC) mean during curing for a period of 20 seconds were measured and analyzeds • A PH reading The pH of each material's supernatant was measured using a pH meter. The findings were calculated immediately, three hours later, and 24 hours afterwards. As a control, a buffering solution was applied. The standard deviation of the pH mean values was then calculated.. T test is used to assess the data. Results: Dycal and thercal tested materials Showed a very alkaline pH afte 3 hours and gradual decreased in pH after 24 hours with no significant differences between the tested materials. Photo activation of the tested materials provided more polymerization of theracal than dycal with no significant difference between them( p value >0.05 ). Conclusion: Different modification should be made to increase the physical and chemical activity of the pulp capping materials.

Background: One of the most serious problems concerning denture performance is the possibility of prosthetic tooth displacement due to increased chewing efficiency. The nature of the mechanical bonding between thermoplastic denture base materials and acrylic teeth has aggravated the problem of tooth debonding. The study aiming to examine the strength of shear bond between prosthetic teeth and thermoplastic base material utilizing silano (silane coupling agent) and mechanical surface modifications (Alumin-ablasting, T. Shape hole) of tooth ridge lap pre and post (100 hrs.) of accelerated ageing conditions. Materials and method: The surface treatments of (120) maxillary central incisors were chosen and grouped into 6 groups of 20 samples each. Each group split into before and after (100hrs.) according to ageing (n=10). Measurement of shear bonding strength applied by a universal testing equipment with 0.5mm/min crosshead speed. Statistical analyses were done using one-way ANOVA test and Tukey’s (HSD) test. Results: Statistics showed high significant variation in average binding force after several surface manipulations in contrast to the control group at (P < 0.000). Regarding surface manipulations, dual treatment of “Alumina-blasting + silano “revealed significant elevation of binding strength in compare to “alumina-blasting” alone (P < 0.001). Similarly, with “T. hole + silano” yielded in greatly increased bonding strength compared to using “T. hole” alone (P < 0.001). a great reduction in bonding strength value was indicated along all treated groups after ageing process (P < 0.000) except the group treated with “T. Hole + silano” show non-significant variations at (p = 0.112). Conclusion: combination treatment (chemo-mechanically) with “T. Hole + silano” improve shear binding strength and not effected with ageing process.

Objective: Comparison of the effectiveness of Bio pure MTAD (mixture of Doxycycline, citric acid and a detergent) versus vanillin(V) as an endodontic aqueous solutions for tested canals infected with E. faecalis and S. Mutans.
Materials and methods : Fourty human extracted lower bicusped teeth (single-rooted) unit at the cementoenamel junction (CEJ) were decoronated. Thereafter, the teeth were prepared with Protper NiTi rotary files till (F3 [30/.06). Then samples are often divided into “2” main groups (18/each), infected by bacteria and incubated in brain heart infusion (BHI) for forty-eight hours at “37°C”. Then the teeth were sub-divided into three groups(N=6) according to the irrigation protocol (MTAD, V, and Distilled water”DW”, which was the control group ”Gp.”).-ve control(N=4). Dentin chips were removed from the canals by sterile low-speed handpiece spherical bur, transfered to BHI, then cultured to count the growing colonies which were recorded as colony forming unit (CFU).Results : Siginficant differences were found in the bactericidal efficacy of (Bio pure MTAD, V and DW) irrigations. Conclusion:Bio pure MTAD had the maximum antibacterial efficacy on E.faecalis and S. mutans as compared to vanillin and DW. Significance and impact of the study: Understanding the mode of action of natural antimicrobials(V) on endodontic therapy may facilitate their application as natural endodontic solutions, particularly for their potential use in endodontic irrigation protocol employing multiple hurdles.Additionally compared these natural compound with artificial one like MTAD and so on.

The aim of this study was to assess various chemical solutions on the surfaces of glass fiber post could affect its flexural strength. A total of 80 Glass Fiber posts were divided into eight groups (n=10) based on surface treatment, untreated surface (control), 10% hydrofluoric acid (HF) for 1 minutes, 10% HF for 2 min, 24% hydrogen peroxide (H2O2) for 4 min, 24% H2O2 for 10 min, 35% H2O2 for 4 min, 35% H2O2 for 10 min, and chloroform solution for 1 hour. Fiber posts were immersed in the solutions for the required amount of time and then rinsed and dried. Fiber posts were loaded in three-point bending test using a mechanical testing machine, data recorded and Flexural strength (σ) was measured. Statistical analysis revealed that the highest value of flexural strength was shown in the group treated with 24% H2O2for 4minfollowed by Chloroform group, so they have no significant effect on flexural strength. While the least value was shown in group treated with10% HF for 2min.Treatment with HF significantly decrease flexural strength for both application times. Treatment with H2O2 showed significant decrease only in group treated with 35% H2O2 for 10 min. It was concluded that strong acid etching of HF and long application time of higher concentration of H2O2 had adverse effect on fiber post flexural strength.

Currently in-office bleaching procedure is the most frequently used in dentistry which represents the most traditional way to modify the color of teeth. The objective of the study is to investigate the pulp response to in-office bleaching procedure with two different concentration of bleaching products by immunohistochemical assessment for Substance P which represent main neuropeptide located in the sensory nerves of the pulp. Twenty four male albino rats were randomly divided equally into two groups. The right maxillary molars were subjected to a single in-office bleaching session with 40% of hydrogen peroxide (Opalescence Boost, UT, USA) (group A) and with 30% of hydrogen peroxide (Philips Dash, USA) (group B). The left maxillary molars in both groups received no treatment used as (negative control). the pulp response were evaluated in 1st day (n=6) and 7th day (n=6) after bleaching procedure. The upper jaws were processed for H&E stain and immunohistochemical localization of substance P. At 1st day there was high mean value of dental pulp cells that positively expressed for substance P antibody in both bleached groups and mostly in 40% bleached group (group A 30.133, group B 27.267) than control group (10.358) with significant p value (0.013) while at 7th day this expression was reduced in both groups(mean value of group A was 15.300 while the group B was 11.400). In conclusion the higher the concentration of hydrogen peroxide in bleaching products the further damage to the pulp represents in neurogenic inflammation which explain the increasing in substance P expression.

Backgrounds: Bones healing is a complex multi steps process, Moringa Oliefera”s flavonoids and Marine collagen enhance minerals density of bones.Objectives: Differences in healing process in bones where evaluated in this study among bone defects that heal normally ( control group) and (experimental groups) using Marine collagen (MC), Moringa oleifera extract (MO) and combination of (MO &MC). Material and Methods: in this study twenty albino rats, after anesthesia bone defects were created in both femurs by drilling. In ten rats, the right bone defects left to heal normally, and left MO added to the bone defects, in other ten rats MC added to the right bone defects, left defects treated with MO & MC. Rats were scarified after 2 and 4 weeks. Immunohistochemical analysis of bone marrow stromal cells, osteocytes, osteoblasts and osteoclasts done using Procollagen type I N-terminal Propeptide (PINP). Results: Immunohistochemical result revealed stronger positive expression of PINP in bone defects treated with (MO&MC) than that other groups Conclusions: Treatment of bone defects with MO and MC showed increase osteogenic capacity by increase the immunoreactivity of PINP.

Background: Saliva is the first defense system of the body through its antioxidant status (total antioxidant capacity), which is either enzymatic or non-enzymatic antioxidants, which block the process of oxidation by neutralizing free radicals; therefore, the objective of this review is to evaluate the role of salivary antioxidant biomarkers in the diagnosis and monitoring of many oral and periodontal diseases and related systemic disorders. Method: We searched for articles published on PubMed and Google Scholar in the last 20 years and then filtered the mints 60 papers according to the following keywords: saliva, total antioxidant capacity (TAC) and oxidative stress (OS). Conclusion: Saliva samples can be beneficial in demonstrating oxidant-antioxidant balance in oral and systemic illnesses and may be a suitable sample type in the diagnosis and monitoring of many pathologies in the body.

Background: Because of their aesthetic appeal, whitening toothpastes are now a common habit, especially among young adults. The effects of brushing with those novel dentifrices on the wear characteristics of resin composites are unknown. Materials and Methods Sixty prepared samples of composite resin fabricate in plastic matrix and stored in distilled water for 24h. For surface roughness measurements, using Stylus profilometer and this considered initial roughness value. The specimens were randomly divided into three groups. Group A use distal water (Control Group), group B Oral B 3D White Perfection toothpaste, group C Colgate Luminous White Brilliant. After this, the electric toothbrush was used to brush the specimens in the three groups investigated for 2 minutes twice a day for 30 consecutive days, Surface roughness measurements using also stylus profilometer and micro hardness test this considered final values. Result: In Experiment there was greater diffrenss in GB and G C in relation to GA, with no differences among them. Conclusion: whitening dentifrices containing Blue covarine (optical agent) have an influential effect on surface characteristics (Superficial roughness and micro hardness) of nanoparticular composite resin.

Periodontal diseases can be defined as a wide range inflammatory condition due to the infection with pathogenic bacteria grow in oral cavity affecting the supporting structure of the teeth. Local plus systemic conditions are affected the initiating and progressing of periodontal infections. Blood groups and Rh factor may play important role in periodontal illness. The aim of present study was to find if there are relation between ABO blood groups and Rhesus factor with periodontal status and if they are possible risk factors or not according to many studies that were done throughout the world.

Background: Being healthcare professionals, technicians must be aware of the safe disposal of biomedical waste and the recycling of dental materials to reduce biological risks to the environment. Objectives: Aim of the current study to evaluation the PMMA surface roughness and hardness after recycling and reuse of waste zirconia material from the CAD/CAM production method as effective filler. Materials and Methods: The Zirconia fiber was collected from the CAM machine after the milling procedure. Then, standard sieves for ISO standardization no. 40, 60 and 100 were used respectively to reach a fine grain size of 150μm. Zirconia of 1% wt. it was added to the PMMA resin base of 99% wt., Zirconia of 3% wt. it was added to the PMMA resin base of 97% wt and Zirconia at 5% wt. it has been added to PMMA resin base of 95% wt. to reach a PMMA/Zirconia composite of three different filler ratios then compared with Polymethyl methacrylate without additives. The conventional heat-curing method using a water bath was applied to polymerize the disc samples for both surface roughness and hardness tests. The data of this study are analyzed by One-way ANOVA (post-hoc/Tukey test) performed at a significant P-value of (p≤0.05) and a 95%confidence level. Results: After comparing the results, a significant difference was observed in the surface roughness and hardness of PMMA/5% Zirconia composites compared to other tested groups (p≤0.05). Conclusion: The 1%, 3% and 5% wt. of Zirconia -fibers as a filler would be an effective percentage to decrease the surface roughness of the PMMA 5% wt. of Zirconia -fibers as a filler would be an effective percentage to increase the surface hardness of the PMMA.

Introduction: disinfection of dentures and soft denture liners was prioritized for cross-contamination management and patient safety. However, it has been shown that these approaches have an influence on the physical and mechanical qualities of denture liners. Objective: assessment of the effect of disinfection by sodium hypochlorite and cleansing tablet on surface hardness and roughness of an acrylic-based soft liner. Material and Methods: 15 specimens were prepared for each test, and then divided into three groups (2% NaOCl, Protefix tablet, and control). The specimen’s preparation was done by conventional procedures according to manufacturing instructions. The daily disinfection of specimens was continued for 30 days. After each immersion in a denture cleanser, distilled water was used to maintain the specimens at room temperature. Hardness and roughness measurements were made by shore A durometer and profilometer devices respectively and the results were analyzed by ANOVA test. Results: there were no significant differences in the hardness value between the examined groups, with the high mean value obtained with the cleansing tablet group, whereas the low value was obtained in the control group. When compared to the control group, the soft-liner increased surface roughness significantly in the NaOCl group, but just slightly and not significantly in the cleaning tablet group. Conclusion: the denture cleansers employed in this investigation had no significant effect on the soft liner's hardness. When compared with a control group, sodium hypochlorite significantly increased the surface roughness of the soft liner, while the cleansing tablet was not significantly affected the surface smoothness.

Background: As usual "Poly methyl methacrylate (PMMA)" resin was stilled the greatest material used for denture foundations despite their identified disadvantage. Attempts to overwhelm these difficulties were advanced through the introduction of new denture base materials counting the injection-moulded thermoplastic resins. Aim: To assess and compare the surface hardness of thermoplastic resin material before and after different treatments. Material and Methods: Whole of 40 circular specimens of dimensions (30 mm × 2 mm-diameter and thickness respectively) divided into fourgroup according to the surface treatment. Each group ofmaterial have (10) specimens. The first group was polishedwith pumice, the second group was polished with pumice andthen glazed, the third group was polished with burninginvestment and then glaze and the fourth group was finishedand glazed without adding any polishing material. Digitalsurface hardness tester meter Shore (D) device was used forindicating the value rigidity of specimens after surfacepolishing treatment. Results: After comparing the results, InGeneral, there were significance difference among the controland experimental groups (P ≤ 0.05). Conclusions: - The meanvalues of the surface rigidity test were decreased in thecontrol groups of De-flex material, while the surface hardnesstest was increased in the experimental groups after polishingwith Glaze material.

Aim: The objective of this study was to evaluate the effect of thermo cycling on fracture resistance of temporary prosthesis constriction by computer-aided design/ computer-aided manufacturing (CAD/CAM) with those of composite materials. Material and Methods: A dentoform maxillary molar tooth was prepared for full coverage crown, temporary prosthesis was constriction and divided into the following groups: CAD/CAM poly (methyl methacrylate) (PMMA) blocks, and auto- polymerizing temporary material. All specimens were subjected to thermo cycling and then fracture strength was measured by a universal testing machine. Results: The mean ± Stander deviation values for CAD CAM group before thermo cycling (560.50 ±83.581 Newton) and after thermo cycling (901.00± 311.598 Newton) were recorded statistically significant higher fracture resistance mean compared with composite fabricated interim restorations. Conclusion: Interim prosthesis constructed using CAD CAM technique showed higher fracture resistance and suitable for long-term clinical performance.

Introduction: Heat cured resins are commonly utilized for construction of complete and partial dentures. Such materials have poor mechanical properties and may be exposed to fracture. The present study, therefore, was conducted to evaluate the impact of incorporating ZnO on acrylic resins’ surface hardness. Materials and Methods: Twenty specimens were constructed in total. The study composed of 2 major sets, and each set had ten specimens. The 1st set had 1% zinc oxide and the second group had no zinc oxide and considered as control. All samples were subjected to the hardness test three times and average reading was recorded for all specimens. Results: a significant decrease in the surface hardness of acrylic resins following the incorporation of ZnO (control group: 127.62+2.53 g/mm2, zinc oxide group: 106.67+ 1.51). Conclusions: The addition of zinc oxide at 1 % would decrease the surface hardness of acrylic resins.