Tag: pubmed

J Contemp Dent Pract. 2023 Aug 1;24(8):587-594. doi: 10.5005/jp-journals-10024-3548.

ABSTRACT

AIM: The purpose of this research was to explore how various finishing and polishing techniques affect the surface roughness (Ra) and gloss of flowable bulk-fill injectable resin composite utilized for posterior teeth restoration, following exposure to a range of food-simulating liquids (FSLs) over three months.

MATERIALS AND METHODS: This study comprised fifty-six disk specimens of G-aenial™ Bulk Injectable flowable resin composite which were created using a Teflon mold (10 × 4 mm). Two techniques of finishing and polishing (F/P) were employed: The two-step 3M™ Sof-Lex™ F/P spiral wheels system and the multiple-step 3M™ Sof-Lex™ XT finishing disks supplemented by the Ultradent Jiffy HiShine polisher cup system. The Ra and gloss of the prepared specimens were measured using an interference microscope system and Horiba gloss checker respectively, immediately post-finishing and polishing and then reassessed after three months in artificial saliva and Coca-Cola.

RESULTS: The two-step system showed a statistically significant difference, exhibiting greater “surface roughness (Ra)” and lower “surface gloss (GU)” mean values compared to the multiple-step system under different storage conditions, particularly after 3 months of storage (p = 0.001).

CONCLUSION: The multiple-step polishing system improved the “Ra” and “GU” of resin composite, suggesting their suitability for posterior resin composite restorations. Acidic media had a deleterious impact on the “Ra” and “GU” of resin composite restoration.

CLINICAL SIGNIFICANCE: The quality of resin composite restorations can be significantly improved with the correct use of finishing and polishing systems, particularly in complex areas of posterior teeth restorations, leading to successful dental procedures.

PMID:38193183 | DOI:10.5005/jp-journals-10024-3548

J Contemp Dent Pract. 2023 Aug 1;24(8):576-581. doi: 10.5005/jp-journals-10024-3546.

ABSTRACT

AIM: To compare the fracture resistance and the mode of failure between monolith second-generation zirconia and bilayered first-generation zirconia single crowns cemented by resin cement and glass ionomer cement (GIC).

MATERIALS AND METHODS: A total of 36 maxillary first premolar crowns (5 mm in length × 4 mm in cervical diameter, with a base of 6 mm) were computer-aided design-computer-aided manufacturing (CAD-CAM) milled. They were divided into the following two groups (n = 18) according to the fabrication techniques: Group M – monolith zirconia crown (1-mm axial thickness and 2-mm occlusal thickness) and group B – bilayer zirconia crown (0.5-mm axial thickness and 1-mm occlusal thickness). Each group was further subdivided into the following two subgroups (n = 9) according to the cement used: Subgroup G – cemented using GIC; subgroup R – cemented using resin cement. All crowns were cemented to their corresponding resin dies and stored in distilled water for 72 hours. Each specimen was mounted to the lower member of the universal testing machine with a load cell of 5 kN and a crosshead speed of 0.5 mm/minute. Failure modes were analyzed for fractured parts using scanning electron microscopy (SEM).

RESULTS: Subgroup MR recorded the highest fracture resistance mean value (3616 ± 347.2 N) while the BG subgroup recorded the statistically significant lowest fracture resistance mean value (1728.7 ± 115.3 N). One-way analysis of variance (ANOVA) followed by pairwise Tukey’s post hoc tests revealed a statistically significant difference (p = 0.0001) between groups M and B. One-way ANOVA followed by pairwise Tukey’s post hoc tests also showed a statistically significant difference (p = 0.0297) between the types of cement used (subgroups G and R).

CONCLUSION: Monolith zirconia crowns had better mean fracture resistance than bilayered zirconia crowns. Resin cement improved the fracture resistance compared to GIC. Monolith zirconia crowns showed bulk fracture while bilayered zirconia crowns showed chipping fracture.

CLINICAL SIGNIFICANCE: Monolith zirconia crowns present a good prosthetic alternative overcoming the veneer chipping drawback of bilayered zirconia crowns. In addition, resin cement could increase the fracture resistance of zirconia crowns.

PMID:38193181 | DOI:10.5005/jp-journals-10024-3546

J Contemp Dent Pract. 2023 Aug 1;24(8):566-569. doi: 10.5005/jp-journals-10024-3509.

ABSTRACT

AIM: The purpose of the current study was to evaluate Titanium and Bioneck TRI implant-abutment interfaces for microgaps and microbiological leakage.

MATERIALS AND METHODS: In this in vitro experiment, 40 dental implants were split into two groups, each of which had 20 samples. Group I: Titanium dental implant, group II: Bioneck TRI. E. coli strain was cultivated in MacConkey media for 24 hours at 37°C. To achieve a bacterial concentration of 1 × 10⁸ colony-forming units per mL at 0.5 scale of MacFarland, the brain-heart infusion (BHI) broth was injected. The CFU count was done to evaluate the microbial leakage. The parts were first submerged, carefully cleaned in an ultrasonic bath, and then installed using a digital torque meter with a 20 N/cm preload. These were attached to a stub of approximately 13 mm using carbon tape, and the microgap evaluation was performed using a scanning electron microscope at a magnification of x1000. Unpaired t-test was used for the calculated data’s statistical analysis. The p-value less than 0.05 was considered as statistically significant.

RESULTS: The maximum microbial leakage was in Bioneck TRI implants (10000 ± 0.01) followed by Titanium dental implants (8.60 ± 3.16). The mean difference was 9991.40 and there was a statistically significant difference found between the two different groups. The maximum microgap was found in the Bioneck TRI implants (9.72 ± 0.96), followed by Titanium dental implant (6.82 ± 1.10) and there was a statistically significant difference was found between the groups (p < 0.001).

CONCLUSION: The present study concluded that the microorganisms can infiltrate the microgap between the implant and abutment interface. When compared with Titanium dental implants, Bioneck TRI implants showed significantly higher levels of microbial leakage.

CLINICAL SIGNIFICANCE: A microgap between the implant and abutment connection might operate as a bacterial source, may produce inflammation, even osseointegration in danger, and subsequently alter clinical and histological parameters. Therefore, having an understanding of the compatible components aids in overcoming treatment planning challenges.

PMID:38193179 | DOI:10.5005/jp-journals-10024-3509

J Contemp Dent Pract. 2023 Aug 1;24(8):560-565. doi: 10.5005/jp-journals-10024-3538.

ABSTRACT

AIM: The aim of the study was to assess the prevalence of tooth shade and its correlation with blood type.

MATERIALS AND METHODS: This study analyzed 312 blood donors at the university Hospital in Monastir between November 2021 and June 2022. Both male and female subjects were included, with ages ranging from 18 to 60 years old. Patients with certain dental conditions or habits were excluded from the study. The study recorded various information about blood donors, including gender, age, governorate of origin, tooth shade, and blood type. The tooth shade values were recorded using A-D shade guide. Data input and tabulation were carried out using Microsoft Excel 2016 and SPSS (version 25.0).

RESULTS: The study included 312 participants, with 85.58% males and 14.42% females. Tooth shade value B was the most prevalent (43%), and D was the least prevalent (7%). The statistical analysis showed that there was no significant link between tooth shade and blood type. However, there were three statistically significant categories: Blood type B/Tooth shade B, Blood type O/Tooth shade C, and Blood Type O/Tooth shade D.

CONCLUSION: The study examined the link between tooth color and blood type but did not find a significant link. However, significant values were found in different subgroups. A wider selection of subjects and a more rigorous measurement equipment might lead to more favorable results.

CLINICAL SIGNIFICANCE: By considering the patient’s blood type alongside other relevant factors, clinicians can enhance the accuracy and precision of tooth shade selection, resulting in harmonious and natural-looking dental restorations. This approach improves patient satisfaction and acceptance.

PMID:38193178 | DOI:10.5005/jp-journals-10024-3538

J Contemp Dent Pract. 2023 Aug 1;24(8):556-559. doi: 10.5005/jp-journals-10024-3508.

ABSTRACT

AIM: The purpose of the current study was to evaluate the impact of three different denture cleansers on the strength and surface roughness of heat-polymerizing resin.

MATERIALS AND METHODS: A total of 120 resin discs (10 mm in diameter and 2 mm thick) were created using a stainless steel mold for surface roughness testing and flexural strength testing (in accordance with the American Dental Association (ADA) Specification No.12). Samples were divided into one of three groups (40 samples in each group): group I: Clanden, group II: Clinsodent, group III: Fittydent. Samples were immersed in denture-cleansing solutions for 30 minutes every day, and this process was repeated over a period of 15 days. Samples were stored in distilled water at room temperature in between the immersions. A surface analyzer was utilized to compare the surface roughness of each sample before and after immersion treatments. For recording flexural strength, each sample was subjected to three-point bending test by mounting samples on Universal testing machine. Comparing mean values between groups using one-way ANOVA and the Tukeys honest significant difference (HSD) post hoc test. A significance level of 0.05 was used for all statistical calculations Results: After 15 days, the maximum change of mean surface roughness of heat-polymerizing resin was found in Clanden denture cleanser group (2.64 ± 0.12) followed by Clinsodent group (2.26 ± 0.09) and Fittydent group (1.92 ± 0.06). After 15 days, the maximum change of mean flexural strength changes of heat-polymerizing resin was found in Clanden denture cleanser group (94.78 ± 0.14), followed by Fittydent group (98.64 ± 0.03) and Clinsodent group (99.26 ± 0.21).

CONCLUSION: Within the limitation, the current study concluded that changes were observed in surface roughness and flexural strength of all heat-polymerizing resin samples after immersion in all three denture cleansers; but least surface roughness and flexural strength changes were observed with the Fittydent cleanser group and Clinsodent group, respectively.

CLINICAL SIGNIFICANCE: Cleaning dentures is crucial for maintaining both the prosthesis and oral health; therefore, it is necessary to select a cleanser that is effective without negatively affecting the base resin’s qualities over time.

PMID:38193177 | DOI:10.5005/jp-journals-10024-3508

J Contemp Dent Pract. 2023 Aug 1;24(8):551-555. doi: 10.5005/jp-journals-10024-3543.

ABSTRACT

AIM: To evaluate in vitro the antibacterial efficacy of Matricaria recutita (chamomile) essential oil at 50 and 75% against Porphyromonas gingivalis ATCC 33277 and Prevotella intermedia ATCC 25611 at 24 and 48 hours.

MATERIAL AND METHODS: The sample consisted of 80 discs and Mueller-Hinton Agar, the medium chosen for the culture. To determine the bacterial sensitivity, discs were placed in each Petri dish with concentrations of essential oil at 50 and 75%, distilled water and 0.12% chlorhexidine. Subsequently, the inhibition halos were measured in millimeters at 24 and 48 hours after culture, with the Kirby-Bauer disk diffusion method.

RESULTS: In groups treated with Porphyromonas gingivalis, measurements at 24 and 48 hours yielded 22.14 ± 2.61 and 22.63 ± 2.67 mm for 0.12% chlorhexidine, 18.90 ± 0.41 and 19.22 ± 0.54 mm for 75% essential oil, and 15.55 ± 0.45 and 15.77 ± 0.46 mm for 50% essential oil, respectively. No statistically significant differences were observed among the groups (p > 0.05).

CONCLUSION: No significant differences were found between the antibacterial efficacy of 0.12% chlorhexidine and 50 and 75% essential oil of Matricaria recutita on Porphyromonas gingivalis and Prevotella intermedia at 24 and 48 hours.

CLINICAL SIGNIFICANCE: The study demonstrates that essential oil derived from Matricaria recutita may effectively combat bacteria associated with periodontal disease. This discovery has the potential to impact dental practice by introducing a natural treatment option. Further research is warranted to fully elucidate the clinical significance and potential applications of this finding.

PMID:38193176 | DOI:10.5005/jp-journals-10024-3543

J Contemp Dent Pract. 2023 Aug 1;24(8):545-550. doi: 10.5005/jp-journals-10024-3554.

ABSTRACT

AIM: The color difference between the final shade of restorations milled from different zirconia blocks, and the control teeth in the esthetic zone is yet uncertain.

MATERIALS AND METHODS: For eight patients who required a singular maxillary central incisor restoration, twenty-four crowns made of zirconia were created. These were grouped into three categories based on the shade and nature of zirconia (Zr) utilized (white core, colored core, and monolithic high-translucency (ht) Zr crowns). The difference in color (ΔE) between the three zirconia crowns and the neighboring teeth was calculated by the use of Easyshade spectrophotometer. Two shades of resin luting cement were used. The measured ΔE values were evaluated based on a clinically acceptable color difference of 1.6ΔE, which is not visible to the human eye.

RESULTS: Among the three groups, no differences of statistical significance were observed in terms of ΔE with different Zr types and resin cement color.

CONCLUSION: Within the limits of this study, the usage of different shades of zirconia blanks and resin cements did not display a statistically significant effect on the final color of the crown.

CLINICAL SIGNIFICANCE: Changing the shade of resin cements does not appear to add value to the final shade of crown. In addition, the generation of zirconia does not influence the shade of the crown. Crowns made of zirconia can be cemented with opaque or transparent cement with no effect on the final color.

PMID:38193175 | DOI:10.5005/jp-journals-10024-3554

Am J Trop Med Hyg. 2024 Jan 9:tpmd230561. doi: 10.4269/ajtmh.23-0561. Online ahead of print.

ABSTRACT

Hepatitis C (HC) presents a substantial burden, and a goal has been established for ending HC epidemics by 2030. This study aimed to monitor HC epidemics by designing a paradigmatic autoregressive fractionally integrated moving average (ARFIMA) for projections until 2030, and evaluating its efficacy compared with the autoregressive integrated moving average (ARIMA). Monthly HC incidence data in Henan from January 2004 to June 2023 were obtained. Two periods (January 2004 to June 2022 and January 2004 to December 2015) were treated as training sets to build both models, whereas the remaining periods served as test sets to perform performance evaluation. There were 465,196 HC cases, with an escalation in incidence (average annual percentage change = 8.64, 95% CI: 3.71-13.80) and a peak in March and a trough in February. For both the 12 and 90 holdout data forecasts, ARFIMA generated lower errors than ARIMA across various metrics: mean absolute deviation (252.93 versus 262.28 and 235.37 versus 1,689.65), mean absolute percentage error (0.17 versus 0.18 and 0.14 versus 0.87), root mean square error (350.31 versus 362.31 and 311.96 versus 1,905.71), mean error rate (0.14 versus 0.15 and 0.11 versus 0.82), and root mean square percentage error (0.26 versus 0.26 and 0.24 versus 1.01). Autoregressive fractionally integrated moving average predicted 181,650 (95% CI: 46,518-316,783) HC cases, averaging 22,706 (95% CI: 5,815-39,598) cases annually during 2023-2030. Henan faces challenges in eliminating HC epidemics, emphasizing the need for strengthened strategies. Autoregressive fractionally integrated moving average can offer evidence-based insights for public health measures.

PMID:38190747 | DOI:10.4269/ajtmh.23-0561

Am J Trop Med Hyg. 2024 Jan 9:tpmd230365. doi: 10.4269/ajtmh.23-0365. Online ahead of print.

ABSTRACT

The WHO aims to detect 90% of global cases of hepatitis B virus (HBV) by 2030. Sub-Saharan Africa carries a disproportionate burden of HBV and hepatocellular carcinoma (HCC). In this study, we sought to assess the utility of a combined HBV and HCC screening program in Tanzania. We conducted a prospective, serial cross-sectional study of patients who participated in a combined HBV and HCC screening program at a regional referral hospital emergency department (ED) in Arusha, Tanzania, between April 19, 2022 and June 3, 2022. All patients completed a study questionnaire and were tested for HBV surface antigen. Patients who were HBV positive were screened for HCC via point-of-care ultrasound (POCUS). The primary outcome was the number of new HBV diagnoses. Data were analyzed with descriptive statistics. A total of 846 patients were tested for HBV (primary ED: 761, clinic referral: 85). The median age of patients was 44 ± 15 years, and 66% were female. Only 15% of patients reported having a primary care doctor. Thirteen percent of patients had been previously vaccinated for HBV. There were 17 new HBV diagnoses (primary ED: 16, clinic referral: 1), which corresponds to a seroprevalence of 2.0% (95% CI: 1.2%, 3.2%). No patients had liver masses detected on POCUS. An ED-based, combined HBV and HCC screening protocol can be feasibly implemented. This study could serve as a model for HBV/HCC screening in regions with high HBV endemicity and low rates of community screening.

PMID:38190742 | DOI:10.4269/ajtmh.23-0365

J Phys Condens Matter. 2024 Jan 8. doi: 10.1088/1361-648X/ad1bf9. Online ahead of print.

ABSTRACT

It is essential to understand to what extent the protected edge states of topological insulators (TIs) can survive against the degradation of the ubiquitous disorders in realistic devices. From a different perspective, disorders can also help to enrich the applications by modulation of the phases in TIs. In this work, the phases and phase transitions in stanene, a two-dimensional TI, have been investigated via the statistical approach based on the random matrix theory. Using a tight binding model with Aderson disorder term and the Landauer-Büttiker formalism, we calculated the conductance of realistic stanene ribbons of tens of nanometers long with random disorders. The calculated phase diagram presents TI in the gap, metal in high energy and ordinary insulator (OI) in large disorder region. Increasing the width of the ribbon can significantly enhance the robustness of TI phase against disorders. Due to different underlying symmetries, the metallic phase can be further categorized into unitary and orthogonal classes according to the calculated universal conductance fluctuations. The local density of states (LDOS) is calculated, showing characteristic patterns, which can facilitate the experimental identification of the phases. It is found that different phases have distinguishing statistical distribution of conductance. Whereas at the phase boundary the distribution exhibits intermediate features to show where the phase transition occurs. To reveal the phase evolution process, we further studied the effects of the disorders on respective transmission channels. It is found that when phase transition takes place, the major transmission channels of the old phase are fading and the new channels of the new phase are emerging.&#xD.

PMID:38190736 | DOI:10.1088/1361-648X/ad1bf9