MUSTANSIRIA DENTAL JOURNAL

Background: Bees naturally create propolis from plant exudates mixed with pollen, wax, and enzymes. It has anti-inflammatory and antibacterial qualities well-known. Adhering firmly to the surfaces of teeth and other complicated structures in the mouth, plaque is a yellowish white or greyish material. The study aimed to assess how lozenges including propolis affected Interleukin-10 (IL-10) levels and plaque development. Method: This study was a Prospective Interventional Controlled Clinical Trial. A total of eighty volunteers were divided into two groups 40 in the study group and 40 in the control group. Following a baseline saliva sample collection, study group volunteers received oral hygiene instruction plus propolis lozenge extract; the Plaque Index was then calculated. Over seven days, they were asked to use the lozenge twice daily, once in the morning and once in the evening. The control group, on the other hand, got just oral hygiene instructions (The importance of dental health and its effect on the overall body, the relevance of daily brushing and flossing, and the avoidance of cariogenic diet). During the second visit, saliva samples were collected again, and the Plaque Index (PI) was measured. Result: The study group observed significant differences between the two visits regarding the mean Plaque Index (PI), whereas the control group did not show significant changes. Additionally, significant differences were found in the mean levels of interleukin-10 in the study group.

Aim: This in vitro study compared the effects of different irrigation solutions on the root canal dentin's microhardness , including 17% ethylenediaminetetraacetic acid (EDTA), 0.5% chitosan nanoparticles (CNP), and Triton.
Materials and Methods: Forty mandibular premolars that had been extracted were chosen, and root length of 14 mm was determined by decorating the samples. The X4 (40/0.06) rotary file for ProTaper Next was used to instrument each sample. After instrumentation, based on an irrigation solution, the samples were randomly split into four groups (n = 10). Groups I (Triton), II (0.5% CNP), III (17% EDTA), and IV (distal water) are the samples. The samples were rinsed by Triton throughout instrumentation with Triton and final irrigation for 1.5 min by 1 ml of Triton, CNP, EDTA, and distal water were rinsed with final irrigation by 5 ml of 0.5% CNP, 17% EDTA, and distal water for 3 minutes, respectively. Following the longitudinal sectioning of the samples, a Vickers microhardness test was performed on them in the apical, middle, and coronal thirds. The mean of these three-thirds was used to determine the microhardness of each sample. ANOVA test was used for statistical evaluation.

Results: There was a significant difference (p≤ 0.05) between all evaluated irrigating solutions, Triton demonstrated the lowest mean of reducing the microhardness compared to the other irrigation solutions followed by CNP and EDTA which had the highest mean of decreasing the root dentin's microhardness.
Conclusions: Comparing this study's irrigation solution to the others, Triton had less of an impact on microhardness. EDTA demonstrated the highest effect on root dentin microhardness in contrast to alternative irrigation methods.

Study objective: To evaluate the ability of nanohydroxyapatite and fluoride varnish to remineralize an artificially induced enamel lesion. Methods: Fifty-four extracted premolar teeth were randomly allocated into three main groups (n=18 each); nanohydroxyapatite (n HAP), fluoride varnish (FL) and untreated control group (C). These groups were further classified into three subgroups (n=6) based on the storage time in artificial saliva (1 week, 2 weeks, 4 weeks). All teeth subjected to pH cycling procedure for induction of white spot lesion. The n-HAP group was treated by immersing the samples in 10% n-HAP solution for three minutes before storing them in artificial saliva. This procedure was repeated daily. The second group treated with fluoride varnish and the third group left untreated. The microhardness was measured at baseline, after pH cycling procedure and after 1-week, 2-weeks, 4-weeks from first time of application of treatment agents and the statistical analysis was performed for the post treatment periods (1, 2, and 4-weeks) to assess the progression of remineralization, with baseline and after pH cycle data serving as reference points to establish the initial condition of the samples. Results: Statistical analysis of mean microhardness values demonstrated a significant difference in microhardness values according to different storage times only for the nanohydroxyapatite group while there were no significant differences in microhardness mean values for fluoride varnish and untreated group.

Conclusion: 10% n-HAP suspension more effective in remineralizing of WSLs as compared to fluoride varnish.

Background: Endodontic irrigants play a crucial role in disinfecting the root canal system. However, none of the currently available irrigants can be considered perfect. Nevertheless, most irrigants containing surfactants in their composition are believed to enhance their antimicrobial activity.
Aim: This study aimed to compare the antimicrobial activity of different active ingredients of root canal irrigants; cetylpyridinium chloride- chlorhexidine combination, chlorhexidine, and MTAD irrigants on different microorganisms (E. faecalis, S. aureus, and Candida albicans).
Method: The direct contact test was used to evaluate the antimicrobial activity of three irrigants (2% chlorhexidine, 2% chlorhexidine + 0.2% cetylpyridinium chloride surfactant, and 100% Biopure MTAD) against Enterococcus faecalis, Staphylococcus aureus, and Candida albicans. The antimicrobial activity was assessed after a 5-minute contact time between the microbial suspension and different irrigant solutions. Subsequently, 10 µl of the treated suspension was cultured and incubated at 37°C for 24 hours. The results were expressed as the kill percentage of viable microbe. Statistical analysis was performed using the Kruskal-Wallis test and the Multiple Wilcoxon sum rank test.
Result: No statistically significant differences were observed in the killing percentages of chlorhexidine, chlorhexidine + cetylpyridinium, and MTAD on Enterococcus faecalis and Staphylococcus aureus (p > 0.05). Against Candida albicans subgroups, both chlorhexidine and chlorhexidine + cetylpyridinium were more effective and statistically significant than MTAD, while chlorhexidine and chlorhexidine + cetylpyridinium have comparable effective.
Conclusion: The addition of cetylpyridinium chloride surfactant to chlorhexidine irrigant did not cause modification or diminishing the in the killing percentages or the antimicrobial activity of chlorhexidine. So, cetylpyridinium chloride can be used in combination with chlorhexidine to overcome some of its drawbacks without changing its antimicrobial activity.

Aim: Endodontically treated teeth (ETT) longevity depends on the ability of restorations to distribute occlusal forces effectively and prevent structural failures. While monolithic lithium disilicate (LDS) endocrowns are widely used, their rigid nature may lead to stress concentration, increasing the risk of failure. Therefore, this study aims to evaluate and compare the stress distribution of monolithic LDS and dual-layered endocrown restorations for endodontically treated mandibular molars using 3D finite element analysis (FEA).
Method: Cone-beam computed tomography (CBCT) was used to scan a sound mandibular first molar, and the data were processed in Mimics Materialise software to create an STL file. Two models were designed in modeling software: Model A (monolithic LDS endocrown) and Model B (dual-layered endocrown with a Lava Ultimate endocore veneered with LDS). The models were meshed using 10-node tetrahedral elements and then subjected to a 600 N axial occlusal load. A stainless-steel indenter with a 6 mm rounded end was used to provide a standardized tripod occlusal contact. Von Mises (VM) criterion was used to investigate the high and low stress patterns within the restoration complex and tooth tissues.
Result: Model A exhibited higher stress concentration at the occlusal surface and cervical regions, with a maximum VM stress of (17.20 MPa) in LDS. In contrast, Model B had a reduced VM stress of (4.87 MPa) in the LDS veneering part and (4.24 MPa) in the endocore. Stress at the enamel was (16.05 MPa) in Model A, decreasing to (9.88 MPa) in Model B. Dentin stress was also lower in Model B (3.49 MPa) compared to Model A (4.37 MPa). The tooth-restoration cement layer exhibited (5.16 MPa) in Model A and (3.49 MPa) in Model B, while the cement layer between the veneering layer and endocore had a VM stress of (3.92 MPa). The flowable composite exhibited a VM stress of 1.63 MPa in Model A and 1.33 MPa in Model B.

ConclusionDual-layered endocrowns demonstrated more favorable stress distribution compared to monolithic designs, suggesting greater durability for restoring endodontically treated teeth. Experimental validation is recommended.

Objective: This research aimed to assess the impact of chicken eggshell, both with and without CO2 laser treatment, on humans enamel white spot lesions in comparison to fluoride sodium gels.
Material and methods: In order to produce white spots on the enamel of the teeth, thirty maxillary first the premolars were divided into three groups at random and submerged in a demineralising solution. Group 1 received treatment with eggshell gel for the demineralised white areas, group 2 had CO2 laser irradiation combined with eggshell gel, and group 3 was treated with sodium fluoride gel. Subsequently, the teeth were immersed in artificial saliva for a duration of 30 days. The hardness of the enamel surface was assessed using the Vickers method. A scanning electron microscope (SEM) was used to analyse a sample from each of the groups in order to identify the enamel surface's morphological characteristics. The data was assessed using Tukey's test and repeated measures one-way analysis of variance (ANOVA).
Results: In all three groups under study, the microhardness of dental white spot lesions increased. The use of eggshell gel combined with CO2 laser therapy (group 2) resulted in a greater increase in microhardness compared to sodium fluoride gel treatments (group 3) and was marginally superior to the use of eggshell gel alone (group 1).
Conclusion: The using of eggshell gel, eggshell gel with CO2 laser, sodium fluoride gel are suggested to reharden the tooth enamel and the treatment with eggshell gel with CO2 laser showed a higher elevation in microhardness than sodium fluoride gel.

Aim: To assess and compare the effectiveness of continuous chelating irrigant’s protocol (Triton, 1-hydroxyethylidene-1,1-bisphosphonate (HEDP) with 5.25% sodium hypochlorite, and with conventional chelation protocol 5.25% NaOCl followed by 17% ethylenediamine tetra-acetic acid (EDTA)) on root canal dentine micro-hardness.
Materials and methods: In this study, forty mandibular premolars extracted for orthodontic purposes were utilized, the teeth were then categorized into four groups based on the type of irrigation solution, Group A; Triton, Group B; HEDP, Group C; EDTA, Group D; Distilled water (control). The crowns were removed to produce root length of 14 mm, ProTaper Next files up to size 40/0.06 were used for teeth preparation, then the roots separated into two parts. The micro-hardness was evaluated at three thirds (coronal, middle, and apical) for each half, 3 N load was used for 15sec. Statistical analysis of the data was performed using one-way ANOVA, followed by the Tukey post hoc test. The level of significance was p ≤ 0.05.

Results: Triton had the least effect on micro-hardness, while EDTA had the highest effect. All chelating agents decrease micro-hardness with no significant difference among them. However, they different significantly from the control group (p ≤ 0.05) at coronal third.
Conclusion: All chelating agents reduced micro-hardness in the three thirds of root canal (coronal, middle, and apical). Among them, Triton and HEDP offer an effective balance between preservation dentine strength and effective cleaning, making them suitable option for endodontists focused on maintaining root strength during treatment.

Aim: To compare the stress distributions in the cervical cavities of four different restorations using Von Mises stress under varying loading directions. Methods: Virtually restored lower first premolar models (n=4) with class V cavities were created from a sound premolar CAD model. Single restorative materials of a resin-modified GIC (model A), a conventional filler composite (CFC) (model B), a combination of short-fiber-reinforced composite-CFC (model C), and a ribbond fiber-CFC (model D) in a bilayered fasion were considered in this study. The FEA models received a 150 N occlusal load in the axial and oblique directions. The stress distribution in the enamel and dentin components of the model and restorative sections was analysed. The maximum von Mises criterion was determined and compared between the tested models. Results: The FEA model indicated that the highest mvM was detected in the enamel structure of the premolar. Notably, greater stresses were observed in the GIC (Model A) and CFC (Model B) restorations than in the combined EverX-CFC restoration (Model C), which resulted in less stress in the enamel and dentin. Finally, the bilayered ribbond-CFC restoration (Model D) had the lowest stress values among the different components of the model. In the oblique loading scenario, all the models with various components presented higher stress values than did those with axial loading, with slightly lower stress values in the fiber-reinforced composite restorations. Conclusion: The incorporation of either glass or polyethylene fibers within the cervical composite restoration apparently enhances stress distributions on the surrounding tooth structure, thus probably improves the retention rate of the restoration.

Aim: The purpose of this study was to evaluate the effect of a collagen cross-linker, grape seed extract (GSE), applied at different times (1, 3, and 5 minutes) on the shear bond strength (SBS) of a universal adhesive bonding system applied to dentine after contamination with blood or blood and hemostatic agent (HA). Materials and Methods: Seventy-two teeth were divided into three main groups. Group A, the control group, consisted of 8 teeth treated only with Scotchbond Universal. The remaining teeth were divided into two contamination groups, B and C, with 32 teeth in each. Group B was contaminated with blood, while Group C was contaminated with both blood and HA. Each contamination group was further divided into four subgroups based on the timing of GSE application. One subgroup did not receive any GSE application, while the other three subgroups had an application of GSE for 1, 3, and 5 minutes, respectively. Then had adhesive application as in group A. After adhesive application and composite resin placement, samples were stored in distilled water at 37° for 24 hours and thermocycled for 500 cycles. SBS was measured using a universal testing machine.

Results: Group B3 (blood and GSE for 3 minutes) and Group C4 (blood, hemostatic agent, and GSE for 5 minutes) showed the highest SBS values at 12.43 MPa and 13.09 MPa, respectively. Conclusion: GSE treatment for durations of 1, 3 or 5 minutes enhanced bond strength to contaminated dentine.