METHODS: A mandibular complete denture was scanned by a desktop scanner to create a digital STL reference file (control). Fifteen identical scans were created by using an intraoral scanner and exported as STL files (test group). These 15 files were saved at 100% of the original scan resolution then reduced to 75%, 50%, 25%, and 10% of their original quality. These 75 scans were statistically analyzed by calculating The Hausdorff Distance (HD) and Dice Similarity Coefficients (DSC) to assess the variation between the mean reduced intraoral scanner files test and the control desktop scanner file and eventual inconsistencies. The volumes of the reduced mesh files were also compared with the 100% resolution intraoral mesh files to evaluate precision and trueness of the intraoral scanner.
RESULTS: Reduced mesh files of 10%, 25%, 50%, 75% of the original scan yielded a percentage similarity average of 99.7%, indicating a very high precision value for the intraoral scanner. Also, the volumes of each associated mesh reduction slightly decreased with non-statistically significant results.
CONCLUSIONS: This study concluded that the chosen intraoral scanner for this study provided very high trueness (98.34%) and precision (99.7%), and also the volumes of reduced mesh files slightly decreased but were not statistically significant.
Materials and Methods: In this in-vitro study, a total of 48 single-rooted permanent human teeth were decoronated, and the roots were treated endodontically. Following post space preparation, the sample was divided into four groups (n= 12 each) based on the types of post and cement. Two different types of post [GC everStick®POST (ES) and Parapost® Fiber LuxTM (PF)], and two different types of cement [G-CEMTM (G), and RelyXTM Unicem (R)] were used according to the manufacturer's instructions. All roots were sectioned at the coronal and middle thirds with a thickness of 3±0.1mm. The Push-out bond strength (PBS) test was performed using a universal testing machine at a cross-head speed of 0.5mm/ min. The bond strength values were recorded, and the data were analyzed using the SPSS program. Apart from descriptive statistics, three-way ANOVA was used for the interaction of the independent variables (post, cement, and root level). For differences between the groups, the Mann-Whitney U test was used. A P-value of less than 0.05 was considered significant for all analyses.
Results: Push-out bond strength of samples at the middle level (11.38±10.31 MPa), with PF posts (11.18±9.98 MPa), and of those luted with RelyXTM Unicem cement (13.26±8.73 MPa) was higher than that of their counterparts. The PBS means of RelyXTM Unicem cement at both root levels were much higher than PBS means of G-CEMTM cement. Three-way ANOVA test revealed a significant effect for each variable with a higher effect of cement (Sum of Squares= 1310.690; P< 0.001). No significant difference (P= 0.153) was found between the coronal and middle parts and between ES and PF posts (P= 0.058). However, a highly significant difference (P< 0.001) was found between RelyXTM Unicem and G-CEMTM cements.
Conclusion: The type of cement had a significant effect on push-out bond strength with RelyXTM Unicem which had higher values than G-CEMTM. However, the type of post and root level had no significant effect on PBS, although Parapost® Fiber LuxTM and middle root level had higher values than their counterparts.
PURPOSE: The purpose of this in vitro study was to evaluate the SR, tensile strength (TS), and percentage elongation (% E) of different SEs subjected to outdoor weathering in the Malaysian climate.
MATERIAL AND METHODS: Type-II dumbbell-shaped specimens (N-120) (nonweathered=15, weathered=15) were made from 3 room-temperature vulcanized (A-2000, A-2006, and A-103) and 1 heat-temperature vulcanized (M-511) silicone (Factor II). For 6 months, weathered specimens were subjected to outdoor weathering inside a custom exposure rack. Simultaneously, the nonweathered specimens were kept in a dehumidifier. Subsequently, the SR was measured with a profilometer; TS and % E were measured by using a universal testing machine. Two-way ANOVA was used to compare the means of the tested properties of the nonweathered and weathered specimens, and pairwise comparison was carried out between the silicones (α=.05).
RESULTS: After outdoor weathering, the SR, TS, and % E were adversely affected by weathering in the Malaysian environment. Among the silicone materials, A-2000 showed the least TS changes (2.51 MPa), while A-2006 demonstrated significant changes in percentage elongation after outdoor weathering (266.5%). M-511 exhibited the highest mean value (2.50 μm) for SR changes. In addition, A-103 SE showed statistically significant differences in most pairwise comparisons for all 3 dependent variables.
CONCLUSIONS: Based on the evaluation of mechanical properties, A-103 can be suggested as a suitable silicone for maxillofacial prostheses fabricated for tropical climates. However, A-2000 can be a suitable alternative, although significant changes to surface roughness were detected after outdoor weathering.
MATERIALS AND METHODS: Three search engines (Google, Yahoo!, and Bing) were searched. The first 20 consecutive websites from each engine were obtained and checked for eligibility. For the quality of the websites, the Health on the Net Foundation Code of Conduct (HONcode), the DISCERN tool, the Journal of the American Medical Association (JAMA) Benchmarks, and Google PageRank were used for the assessment of the included websites. For readability, an online web tool was used, including well-known analyzing indices [Flesch Kincaid grade level (FKGL), Simple Measure of Gobbledygook (SMOG), and Flesch Reading Ease (FRE)]. The acceptable readability level was set to be ≥80.0 for the FRE and <7 for the FKGL and SMOG. The data were presented in frequencies and percentages.
RESULTS: Out of the 60 screened websites, 14 websites were eligible for analysis. There was only one (7.1%) website that had the HONcode seal. The mean score of all websites based on the DISCERN tool was 29.6 ± 12.1, with no website achieved the high score (≥65). Only one (7.1%) website scored >5 based on Google PageRank. Regarding JAMA benchmarks, all websites achieved a mean score of 2.57 ± 1.1. The mean grade level based on the FKGL was 8.4 ± 6.3. All websites had a score of <7 according to the SMOG index. The mean score of the readability ease index was 90.5 ± 16.4.
CONCLUSION: Most of the dental health information on denture hygiene available on the Arabic websites did not have the required level of quality, regardless of being readable and comprehensible by most of the general people.
CLINICAL SIGNIFICANCE: Directing the patients to the appropriate websites related to their cases is the responsibility of the dentists.
METHODS: An online electronic search was performed using the PubMed, Scopus, and Web of Science databases for in vitro studies published from 2010 to 2020 in English. The retrieved eligible studies that compared the fracture resistance of titanium and fiber posts on human teeth were selected. The pooled standardized mean difference (SMD) with a 95% confidence interval was calculated. In addition, the trial sequential analysis (TSA) was performed to test if the available studies are sufficient to make conclusive evidence.
RESULTS: Of the 1165 retrieved studies, 17 studies were included in the qualitative analysis, while 16 studies were included in the quantitative analysis. Because of the high heterogeneity among studies, data from 10 studies were pooled and submitted to TSA. A total of 852 teeth were evaluated for fracture of the posts in 27 independent comparison groups. The pooled effect of the residual studies revealed no significant difference between titanium and fiber posts (SMD = -0.12; 95% CI = -0.30, 0.06; p = 0.20). Results of the TSA revealed no conclusive evidence.
CONCLUSIONS: The results of the current evidence revealed no significant difference between fiber and titanium posts. The evidence is insufficient, and more standardized in vitro studies are required.
METHODS: Relevant articles written in English only, before January 15, 2017, were identified using an electronic search in the PubMed, Scopus, and Google Scholar databases. Furthermore, a manual search of the related major journals was also conducted to identify more pertinent articles. The relevancy of the articles was verified by screening the title, abstract, and full text if they met the inclusion criteria. A total of 37 articles satisfied the criteria, from which data were extracted for qualitative synthesis.
RESULTS: Among the 37 included articles, 14 were without aging, 15 were natural or artificial accelerated aging, 7 were outdoor weathering, and 1 contained both artificial aging and outdoor weathering. Only 4 studies out of the 14 without aging had significant observations; whereas 9 articles with natural or artificial aging published significant results, and 3 out of 7 outdoor weathering articles showed significant changes in the evaluated silicone elastomers.
CONCLUSIONS: Despite the varying research, it seems that the single "ideal" maxillofacial prosthetic material that can provide sufficient resistance against different aging conditions is yet to be identified. Therefore, it is imperative for standardization organizations, the scientific community, and academia to develop modified prosthetic silicones possessing improved physical properties and color stability, limiting the clinical problems regarding degradation of maxillofacial prostheses.
PURPOSE: The purpose of this pilot clinical study was to compare casts generated from a conventional definitive impression with casts generated from an altered cast impression using a 3-dimensional (3D) analysis software program.
MATERIAL AND METHODS: Three partially edentulous participants with mandibular Kennedy Class I were enrolled, and impressions were made with the 2 techniques and poured in stone. The casts were scanned, aligned, and superimposed by using a 3D analysis software program. Surface deviations were measured to evaluate the differences in displacement induced by the impression on the tissue surface. Five observations were made in 4 different areas on each partially edentulous side. Means from these observations were generated, and the Wilcoxon and Mann Whitney tests were performed for all data to assess the differences between the right and left sides in the same participant and among the 3 participants (α=.05).
RESULTS: The casts made from the altered cast impression had an overall mean ±standard deviation displacement of -0.05 ±1.25 mm on the right and left sides of the mandibular buccal shelf area. Moreover, the greatest overall difference of about 0.45 ±0.41 mm occurred on the lingual slope of the residual ridge, and the differences in the other areas were 0.10 ±0.99 mm (crest of the residual ridge) and 0.16 ±0.66 mm (buccal slope of the residual ridge). The overall differences varied statistically between significance and nonsignificance for the same participant and among the 3 participants.
CONCLUSIONS: A digital comparative analysis of the conventional and altered cast methods of recording the bilateral distal extension areas in partially edentulous participants showed that the altered cast method exhibited more displacement on the buccal vestibule or buccal shelf area compared with other examined areas. The differences between the 2 impression methods in the displacement values among the examined areas were minimal and in close proximity, and such differences may lack clinical significance.
METHOD: Resin-modified GIC, Fuji II LC (F2) and high-fluoride cGIC, Fuji VII (F7) were used as controls. HCD was synthesized in-house, incorporated into both RMGIC and cGICs at 1 % and 2 % weight percentages (w/w), and chemically analyzed using Fourier transform infrared (FTIR) spectroscopy. Then, the F2 containing HCD (GIC-HCD F2) and F7 containing HCD (GIC-HCD F7) were evaluated for HCD and fluoride release profiles using UV Visible spectrophotometer and pH/ISE benchtop fluoridemeter, respectively. The antibacterial properties were assessed against Streptococcus sanguinis using the agar well diffusion method and measurement of bacterial growth turbidity, followed by the observation of the bacterial morphology using scanning electron microscope. The data were statistically analyzed using one-way ANOVA and Bonferroni post-hoc tests.
RESULTS: The FTIR spectra confirmed the presence of HCD in the GIC-HCD matrices. HCD was successfully released from both GIC-HCD F2 and GIC-HCD F7 matrices at both weight percentages. Higher fluoride release and inhibitory zones were observed compared to the control groups, with GIC-HCD F2 having a more significant effect than GIC-HCD F7. Additionally, the incorporation of HCD slowed down the growth of Streptococcus sanguinis and showed remarkable changes in bacterial shape specifically on GIC-HCD F2.
CONCLUSION: The incorporation of HCD into both RMGIC and cGIC improved fluoride release and enhanced the antibacterial activities, with a more significant effect observed in RMGIC compared to cGIC.
METHODS: A comprehensive search of was conducted for all relevant in-vitro studies. All randomized controlled in-vitro studies that evaluated the effect of calcium hydroxide on the push-out bond strength of resin-based or calcium silicate-based endodontic sealers were assessed. The variables of interest were extracted, and the risk of the included studies was evaluated. The standardized mean difference was calculated and the significance level was set at p value <0.05.
RESULTS: A total of 26 studies were eligible for analysis. There were 45 independent comparison groups and 1009 recruited teeth. The pooled data showed no significant difference in push-out bond strength between calcium hydroxide and control group in the resin-based group (SMD = 0.03; 95% CI = -0.55, 0.60; p = 0.93), and calcium silicate-based group (SMD = 0.02; 95% CI = -0.31, 0.35; p = 0.90). Most of the studies (21 out of 26) were at medium risk of bias and five studies showed a low risk of bias.
CONCLUSION: The available evidence suggests that calcium hydroxide used as intracanal medication does not influence the push-out bond strength of the resin- and calcium silicate-based endodontic sealers.
CLINICAL SIGNIFICANCE: The results of this meta-analysis suggest that calcium hydroxide used as intracanal medication does not influence the push-out bond strength of resin-based and calcium silicate-based endodontic sealers.