Integrating chemistry, fluid flow, and mechanics to drive spontaneous formation of three-dimensional (3D) patterns in anchored microstructures.

Enzymatic reactions in solution drive the convection of confined fluids throughout the enclosing chambers and thereby couple the processes of reaction and convection. In these systems, the energy released from the chemical reactions generates a force, which propels the fluids' spontaneous motion. Here, we use theoretical and computational modeling to determine how reaction-convection can be harnessed to tailor and control the dynamic behavior of soft matter immersed in solution. Our model system encompasses an array of surface-anchored, flexible posts in a millimeter-sized, fluid-filled chamber. Selected posts are coated with enzymes, which react with dissolved chemicals to produce buoyancy-driven fluid flows. We show that these chemically generated flows exert a force on both the coated (active) and passive posts and thus produce regular, self-organized patterns. Due to the specificity of enzymatic reactions, the posts display controllable kaleidoscopic behavior where one regular pattern is smoothly morphed into another with the addition of certain reactants. These spatiotemporal patterns also form "fingerprints" that distinctly characterize the system, reflecting the type of enzymes used, placement of the enzyme-coated posts, height of the chamber, and bending modulus of the elastic posts. The results reveal how reaction-convection provides concepts for designing soft matter that readily switches among multiple morphologies. This behavior enables microfluidic devices to be spontaneously reconfigured for specific applications without construction of new chambers and the fabrication of standalone sensors that operate without extraneous power sources.

Push-out bond strength and SEM fractographical analysis of hollow fibre posts used with self-adhesive resin cement: a pilot study.

Detachment is the major cause of failure of endodontic fibre posts. Hollow posts have been recently introduced to overcome such issue. The primary aim of this pilot study was to compare the push-out bond strength of hollow posts and traditional solid posts. Eight round-shaped single-canal premolars extracted for periodontal reason were selected as sample and equally randomized into two groups: (i) traditional solid fibre posts-TECH21xop and ii) hollow fibre posts-TECHOLE. A dual-curing self-adhesive cement (new TECHCEM) was used for posts placement. Six horizontal sections-two from each portion of the root (coronal, middle and apical)-were obtained from each sample root, yielding a total of 24 sections for each group. Push-out test was performed on the sections and bond strength values were compared between groups and within each group. Scanning electron microscope (SEM) fractographical analysis was conducted on each section. Additional SEM and EDX analyses were performed on new samples of both posts, to assess fibres density and distribution, and the chemical composition of the fibres and the matrix. Hollow posts showed a significantly higher push-out bond strength (6.36 ± 1.22 MPa) than solid posts (3.64 ± 1.62 MPa). Among the three root portions of the same group, there was no significant difference in bond strength. In both groups, the most frequent type of fracture was a mixed adhesive failure with the cement covering 0 to 50% of the post perimeter. Hollow post fibres appear more similar in size and have a more homogeneous distribution, compared to solid posts. The two post types also have different chemical compositions.

Clinical and laboratorial performance of rehabilitation of endodontically treated teeth: A systematic review.

OBJECTIVE: This systematic review aimed to analyze the clinical (survival rate, failure risk, or fracture) and laboratory performance (fracture mode or failure) of rehabilitations of endodontically treated teeth, with and without posts. MATERIALS AND METHODS: A systematic search was conducted in the Pubmed, Scopus, Web of Science, Embase, Cochrane Library, and OpenGrey databases up to March 2023, according to PRISMA guidelines. In vitro and clinical studies that compared the clinical and laboratory performance of endodontically treated teeth with and without intraradicular posts were included. Studies selection, data extraction, and risk of bias analysis were performed. RESULTS: Thirty-one in vitro and 7 clinical studies were included. For in vitro studies, fiberglass post (n = 24) was the most mentioned. The follow-up time of the clinical studies ranged from 1 to 17 years, with the fiber-reinforced composite post (n = 3) being the most evaluated, and only failure risk proved to be more favorable for using intraradicular posts. CONCLUSION: Rehabilitations of endodontically treated teeth with and without intraradicular retainers showed no difference in fracture resistance and failure mode, evaluated by in vitro studies. Clinical studies showed no difference in survival rate, but failure risk proved to be more favorable for the use of posts. CLINICAL SIGNIFICANCE: This analysis revealed significant variability between results, however, most laboratory and clinical studies revealed no difference with using the post. Furthermore, it is important to emphasize the need to evaluate the coronary remnant and the general characteristics of the tooth in each situation.

Accuracy comparison of single- and double-sleeve endodontic guides for fiber post removal.

BACKGROUND: This study aimed to assess the accuracy of two different endodontic guides for fiber post removal. METHODS: In this in vitro study, 54 maxillary canine fiber posts were mounted on 36 maxillary stone casts; 18 teeth were mounted unilaterally, and 36 teeth were mounted bilaterally. Static endodontic guides were fabricated according to baseline cone-beam computed tomography (CBCT) and intraoral optical scans using Blue Sky software. In the single-sleeve endodontic guides group (SSG), two anterior and two posterior teeth were included in a 5-unit guide. In the double-sleeve endodontic guides group (DSG) group, the guide was passed through the midline to include both canine teeth and extended by 2 teeth posterior to the canine teeth bilaterally (a 10-unit guide). After drilling, postoperative CBCT scans were taken and superimposed on the virtually designed path, and the maximum coronal deviation (MCD) at the marginal entry point of the tooth, maximum apical deviation (MAD) at 10 mm apical to the tooth margin, and maximum angular deflection (MAnD) of the drill were calculated. RESULTS: The mean MCD, MAD, and MAnD were 0.34 mm, 0.6 mm, and 2.32 degrees, respectively, in the SSG and 0.31 mm, 0.7 mm, and 2.37 degrees, respectively, in the DSG. The two groups were not significantly different from each other in terms of MCD (P = 0.573), MAD (P = 0.290), or MAnD (P = 0.896). CONCLUSIONS: The accuracies of the two techniques, the extended double sleeve guide and the single sleeve guide, were comparable and thus DSG may be used for removal of fiber posts in adjacent or distant teeth.

Intensive care nurses' experiences of caring for patients during the COVID-19 pandemic based on an analysis of blog posts.

BACKGROUND: In 2019, coronavirus disease 2019 (COVID-19) broke out worldwide, leading to a pandemic. Studies have shown that COVID-19 patients in intensive care units (ICUs) require more nursing care than other patients. ICU nurses who care for patients with COVID-19 have shown signs of psychological and physical strain. AIM: The aim of this study was to illuminate ICU nurses' experiences of caring for patients with COVID-19 in ICUs during the first wave of the pandemic. STUDY DESIGN: A qualitative, descriptive and inductive approach was used. A total of 70 blog posts from 13 bloggers in the United States, Great Britain, Finland and Sweden were analysed using qualitative inductive manifest content analysis. RESULTS: The results reveal an overall theme: 'An overturned existence under extreme conditions'. Furthermore, three categories-'the virus caused changes in work and private lives', 'unreasonable demands', and to hold on to caring ideals thanks to the support of others'-and seven subcategories were identified. CONCLUSIONS: Caring for patients with COVID-19 during the first wave of the pandemic was demanding because of a lack of knowledge about the disease and the severity of the illness. This led to ICU nurses experiencing extreme conditions that affected various aspects of their lives. Support from colleagues and teamwork were revealed to be particularly important for how nurses dealt with the demands of working during a pandemic, as was sufficient recovery time between work shifts. RELEVANCE TO CLINICAL PRACTICE: Work in ICUs was challenging and demanding, even before the pandemic. This study contributes to an understanding of the complex work environment that existed in hospitals during the first wave of the COVID-19 pandemic. The knowledge obtained from this study can be used to revise working conditions and identify health interventions for ICU nurses.

Removal Efficiency and Effectiveness of Four Different Fiber Posts Using Five Different Drill Systems in Multirooted Teeth.

AIM: In comparing the effectiveness and efficiency of different types of post removal systems in removing different types of fiber posts (FPs), this study aims to shed light on the success of removal by currently available drill systems. MATERIALS AND METHODS: A total of 200 maxillary first molars, were root canal treated and prepared to receive posts. The molars were divided into four groups corresponding to four different FPs: Group RX, Radix FP; Group RF, Reforpost Glass Fiber; Group HI; Hi-Rem Endodontic Post; and Group DT, D.T. Light-Post Illusion X-RO. Fiber posts were done with luting by Gradia Core (GC America, Inc.). Groups were again divided into five subgroups corresponding to the technique by which the FP was removed into as follows: Subgroup P, PD-25-1.1 Drill; subgroup G, GC FP Drill; subgroup E, EasyPost Precision Drill; subgroup R, Reaccess Carbide Double Taper Kit; and subgroup H; H-Endodontic Drill. After posts were removed, effectiveness and efficiency were documented. Data were tabulated and statistically analyzed. RESULTS: Strong significant differences regarding efficiency among groups (FP type) and subgroups (drills used) (p = 0.00) were shown by the one-way analysis of variance (ANOVA) test. Subgroup DT-G scored the longest mean removal time (20.9 minutes) while Subgroup RX-R scored the shortest mean removal time (1.4 minutes) Regarding effectiveness, strong significant differences among groups (p = 0.00) and subgroups (p = 0.00) were shown by one-way ANOVA. Subgroup RF-G scored the highest scale (5.2) whereas subgroup HI-R scored the lowest mean scale (1.2). CONCLUSION: The difference was strongly significant between tested post-removal kits and between tested FPs. Re-access Carbide Double Taper Kit performed superiorly in both effectiveness and efficiency, followed by PD-25-1.1 Drill. Hi-Rem post showed the best retrieving results among other FPs. CLINICAL SIGNIFICANCE: Knowing the best technique and tools for post removal could spare the practitioner any unwanted complications during post removal. How to cite this article: Sayed M, Alahmad AM, Alhajji KS, et al. Removal Efficiency and Effectiveness of Four Different Fiber Posts Using Five Different Drill Systems in Multirooted Teeth. J Contemp Dent Pract 2024;25(1):72-78.

The influence of horizontal glass fiber posts on fracture strength and fracture pattern of endodontically treated teeth: A systematic review and meta-analysis of in vitro studies.

PURPOSE: This systematic review and meta-analysis aimed to summarize available evidence regarding the effect of horizontal glass fiber posts (HGFPs) on fracture strength and fracture pattern of endodontically treated teeth (ETT) compared to controls without HGFP. The review protocol was registered on the OSF registries. METHODS: Literature searches were conducted in MEDLINE/PubMed, Scopus, Web of Science, Embase, Google Scholar, and ProQuest for all relevant studies published up to February 2022. All in vitro studies that assessed the influence of HGFPs on fracture strength and fracture pattern of ETT whether mesio-occluso-distal or mesio-occlusal or DO cavities were considered eligible. Review Manager (RevMan) was used for the meta-analysis. Subgroup and funnel plot analyses were also performed. Quality assessment was conducted by two independent reviewers. RESULTS: A total of 12 articles met the inclusion criteria, and 10 studies underwent quantitative evaluation. The pooled effect showed that fracture resistance of molar teeth restored with HGFP was significantly higher than teeth without HGFP (standardized mean difference [SMD]: 1.61, 95% confidence interval [CI]: 0.14, 3.09, p = 0.03), whereas marginally significant for premolars (SMD: 1.36, 95% CI: -0.00, 2.73, p = 0.05). Regarding fracture patterns, the presence of an HGFP significantly increased the occurrence of restorable fracture patterns for premolars (odds ratios [OR]: 4.15, 95% CI: 1.60, 10.82, p = 0.004) compared to controls, whereas the difference was not significant for molars (OR: 1.09, 95% CI: 0.43, 2.77, p = 0.85). Moderate risk of bias was identified in 9/12 studies; one study showed a high risk of bias and two studies showed a low risk of bias. CONCLUSIONS: Within the limitations of this study, there is evidence from in vitro studies that the use of HGFP increases the fracture resistance of the ETT when compared to teeth without HGFP and also reduces the occurrence of non-restorable fractures for premolars. However, well-conducted in vitro and prospective clinical studies are warranted to validate this finding.

[Investigation on reproductive health status of women workers in different positions in oilfield enterprises].

Objective: The status and influencing factors of reproductive health (including menstrual period and gynecological diseases) of female workers in different positions of oilfield enterprises were analyzed. Methods: From January to December 2020, a total of 979 female workers in an oil field were selected as research objects by the judgment sampling method, and the "Female Reproductive Health Survey" was used as the investigation tool to investigate the demographic characteristics, menstrual status and gynecological diseases. The influential factors were analyzed by 2-test and logistic regression analysis. Results: The prevalence of abnormal menstruation was 26.1% (256/979), dysmenorrhea 53.1% (520/979), and gynecological diseases 54.34% (532/979). The prevalence of breast disease was 23.39% (229/979), uterine disease 11.03% (108/979), cervical disease 10.32% (101/979), and HPV infection 7.97% (78/979). Age, the nature of the job and whether occupational harmful factors were clear were the influencing factors of gynecological diseases (P=0.001, 0.000, 0.007). Age, job nature, working hours and work intensity were the influencing factors of abnormal menstruation (P=0.005, 0.000, 0.000, 0.010) . Conclusion: The reproductive health status of female workers in different positions of oil field enterprises is not optimistic, and the reproductive health status of female workers in professional and technical positions needs to be improved.

A critical review on the fabrication techniques that can enable higher throughput in dielectrophoresis devices.

The sorting of targeted cells in a sample is a cornerstone of healthcare diagnostics and therapeutics. This work focuses on the use of dielectrophoresis for the selective sorting of targeted bioparticles in a sample and how the lack of throughput has been one important practical challenge to its widespread practical implementation. Increasing the cross-sectional area of a channel can lead to higher flow rates and thus the capability to process a larger sample volume per unit of time. However, the required electric field gradient that is generated by polarized electrodes drastically decreases as one moves away from the electrodes. Hence, the scaling up of the channel cross section must be done asymmetrically. One desires a channel aspect ratio AR = height/width that is much smaller or much larger than 1. Since reducing footprint of the DEP device is important to ensure affordability, the use of channels with AR ≫ 1 is desired. This creates the challenge to fabricate electrodes on the sidewalls of multiple channels with AR ≫ 1, or a channel embedding an array of electrodes with a gap in between them with AR ≫ 1. This critical review first details the motivation for using three-dimensional (3D) DEP devices to improve throughput and then describes selected techniques that have been used to fabricate them. Techniques include electrodeposition, deep etching, thick-film photolithography, and co-fabrication. Electrode materials addressed include metals, silicon, carbon, PDMS-based composites as well as conductive polymers and fluids.

The discovery of the use of magnetic navigational information.

The magnetic field of the Earth provides animals with various kinds of information. Its use as a compass was discovered in the mid-1960s in birds, when it was first met with considerable skepticism, because it initially proved difficult to obtain evidence for magnetic sensitivity by conditioning experiments. Meanwhile, a magnetic compass was found to be widespread. It has now been demonstrated in members of all vertebrate classes, in mollusks and several arthropod species, in crustaceans as well as in insects. The use of the geomagnetic field as a 'map' for determining position, although already considered in the nineteenth century, was demonstrated by magnetically simulating displacements only after 2000, namely when animals, tested in the magnetic field of a distant site, responded as if they were physically displaced to that site and compensated for the displacement. Another use of the magnetic field is that as a 'sign post' or trigger: specific magnetic conditions elicit spontaneous responses that are helpful when animals reach the regions where these magnetic characteristics occur. Altogether, the geomagnetic field is a widely used valuable source of navigational information for mobile animals.

Adolescent (mis)perceptions of peer alcohol posts on social media: Prospective associations with alcohol attitudes and use.

BACKGROUND: Social media is a central context in which teens interact with their peers, creating opportunities for them to view, post, and engage with alcohol content. Because adolescent peer interactions largely occur on social media, perceptions of peer alcohol content posting may act as potent risk factors for adolescent alcohol use. Accordingly, the preregistered aims of this study were to (1) compare perceived friend, typical person, and an adolescent's own posting of alcohol content to social media and (2) examine how these perceptions prospectively relate to alcohol willingness, expectancies, and use after accounting for offline perceived peer alcohol use. METHODS: This longitudinal study included 435 adolescents (Mage  = 16.91) in 11th (48%) and 12th grade (52%). Participants completed measures of alcohol content social media posts, perceived peer alcohol use, willingness to drink alcohol, alcohol expectancies, and alcohol use at two time points, 3 months apart. RESULTS: Consistent with preregistered hypotheses, adolescents reported that 60.3% of the typical person their age and 30.6% of their friends post alcohol content on social media. By contrast, only 7% of participants reported that they themselves posted such content to social media. After accounting for offline perceived peer drinking norms, neither perceived friend nor typical person alcohol content social media posts were prospectively associated with willingness to drink or positive or negative alcohol expectancies. Perceived friend alcohol content posts were prospectively positively associated with past 30-day alcohol consumption even after controlling for offline perceived peer drinking norms. CONCLUSIONS: Adolescents misperceived the frequency of alcohol-related posting to social media among their peers, and perceptions of friend alcohol content posts prospectively predicted alcohol use. Given the results from the current study and the ubiquity of social media among adolescents, prevention efforts may benefit from addressing misperceptions of alcohol-related posting to social media.

Effect of root perforation repair with mineral aggregate-based cements on the retention of customized fiberglass posts.

The purpose of this study was to investigate whether the root perforation repair with mineral aggregate-based cements affects the retention of customized fiberglass posts to bovine intraradicular dentin. Sixty-four bovine mandibular incisors had their root canals endodontically treated and prepared for fiberglass posts luting. Teeth were randomly distributed into four groups (n = 16), according to the cement used for the perforations repair (MTA HP; calcium aluminate cement-CAC; and CAC + calcium carbonate nanoparticles-nano-CaCO3) and control group (no perforation). The groups were redistributed according to the fiberglass posts luting protocol (n = 8): total-etching (TE) (MTA HP/TE; CAC/TE; CAC + CaCO3/TE and control/TE) and self-etching (SE) (MTA HP/SE; CAC/SE; CAC + CaCO3/SE and control/SE). Roots were sectioned into 1.3 mm-thick dentin slices obtaining samples that were submitted to the push-out test in Universal Testing Machine (Instron, Model 4444-0.5 mm/min). The fractured samples were analyzed under stereomicroscope and Scanning Electron Microscope (SEM). CAC/TE and CAC/SE groups had significant difference between the cervical and middle thirds (p < 0.05). When the root thirds were not considered, CAC/SE had the lowest bond strength and differed statistically from CAC/TE and CAC + CaCO3/TE groups, which had the highest mean bond strength values (p < 0.05). The root perforations repair did not affect the bond strength of resin cement/customized fiberglass posts to bovine dentin. The increase in bond strength is luting protocol dependent.

Restorative difficulty evaluation system of endodontically treated teeth.

OBJECTIVE: This article provides an updated overview of restorative procedures of endodontically treated teeth. CLINICAL CONSIDERATIONS: The different techniques and procedures to restore an endodontic treated tooth were considered in the last decades. While they are generally performed using bonding procedures in combination with or without the placement of a post into the root to build up the abutment, there has been a lack of interest in restorative difficulties that can be faced. Failures are represented such as debonding of the post, fracture of the root, decementation, and/or fracture of the restoration, microleakage of the margins. Essentially, the presence of a sufficient failure is considered a key point of a long prognosis. Different clinical factors can directly influence the type of restoration and the longevity of the treatment. The restorative difficulty evaluation system (RDES) is proposed in this article. This new system is composed of eight different clinical factors that are divided into six levels of difficulties. The RDES is composed of 1. Endodontic complexity and outcome, 2. Vertical amount of coronal residual structure and dimension of the pulp chamber, 3. Horizontal amount of coronal residual structure, 4. Restoration marginal seal, 5. Local interdisciplinary conditions, 6. the complexity of the treatment planning, 7. Functional need, 8. Dental wear and esthetic need. CONCLUSION: This article reviews the RDES and outlines critical steps and tips for clinical success. CLINICAL SIGNIFICANCE: The RDES allows to any clinician to evaluate restorative difficulties when an endodontic treated tooth must be restored, combines clinical aspects that can involve from the single tooth to a full mouth rehabilitation.

Fracture resistance of thin wall endodontically treated teeth without ferrules restored with various techniques.

OBJECTIVE: To evaluate the fracture resistance and failure characteristics of simulated thin wall endodontically treated teeth without ferrules restored with various techniques. MATERIALS AND METHODS: Forty-eight human mandibular single-root canal premolars were decoronated and endodontically treated. The 1 mm thick remaining root canal dentin was prepared. The roots were randomly divided into four groups of 12 roots according to the following post and core reconstruction techniques: direct resin composite post and core (CP), multiple fiber posts and resin composite core (FP), CAD/CAM anatomical post and core (AP), and metal cast post and core (MP). Full metal crowns were cemented to the cores. All specimens were subjected to thermocycling for 5000 cycles and submitted to axial compression until failure at a 45°angle using a universal testing machine. The failures were classified into one of the followings: post and/or core fractures, root fractures, and root fractures combined with post and/or core fractures. RESULTS: Average failure loads of groups CP, FP, AP, and MP were 360.0, 655.2, 402.7, and 856.1 N, respectively. MP provided the highest failure load, which was significantly higher than those of the other groups (p < 0.05). FP was second, being inferior to MP with a significance level of p = 0.039. CP exhibited the least failure load, and it was not significantly different from the AP group (p > 0.05). Root fractures were the major failure mode for most of the specimens except the CP group, in which composite fractures at the cervical level were commonly observed. CONCLUSION: Metal cast post and core provided the highest fracture resistance for reconstruction of a thin wall in endodontically treated teeth without ferrules, followed by multiple fiber posts and resin composite core. The milled anatomical post and core and a direct resin composite post and core provided significantly lower fracture resistance. CLINICAL SIGNIFICANCE: Metal cast posts and core and multiple fiber posts with resin composite core techniques were effective for restoring severely compromised endodontically treated teeth.

Digital indicators of interest in natural world heritage sites.

Due to their remoteness or boundless nature, activities at Natural Heritage Sites are difficult to monitor. In this study, two digital measures of the interest in Natural Word Heritage Sites are compared: one ex ante based on the number of Wikipedia page views of the site and another ex post derived from actual visitation as measured by the number of Instagram posts. The entire UNESCO database, which includes 248 Natural World Heritage Sites is linked to the 2.8 million Wikipedia page views, the 58 million Instagram posts and the Köppen extreme climate zone categories. Quantile regressions reveal that the main association in common for the two indicators is the risk of the site losing its inscription. Presence in the UNESCO Danger list is associated with reduced interest in a site, particularly in the number of Instagram posts and in the top quartile of Wikipedia views. Years since inscription is also an important explanatory variable, especially for the Instagram posts and the Wikipedia views in the top quartile. The UNESCO selection criterion of outstanding beauty only relates to the Instagram posts. Climate zone is mainly linked to the ex post variable and its upper quartile, where the sites with the most attention are found. Wikipedia views are also negatively associated with sites in Africa, the Arab countries and Latin America. Elevation, size of the area as well as kind of site are all variables not significant. There is a significant correlation between the two outcome variables with a coefficient of 0.5. While the Instagram posts relate clearly to actual visits, the Wikipedia page views is considered a possible leading indicator of future interest in a site.

Comparative evaluation of the force required to fracture coronal segments reattached using different methods.

BACKGROUND/AIM: Anterior teeth are prone to traumatic injuries. Their management is necessary in order to maintain the pulp and esthetics. Various methods have been reported for fragment reattachment of fractured teeth but there is no consensus on which is the best technique. The aim of this study was to compare the force required to fracture reattached fragments using polyethylene fibers in vertical grooves on the external surface of teeth, fiber-reinforced composite post and circumferential chamfer. MATERIAL AND METHODS: Forty-eight extracted maxillary central incisors were sectioned using a disk and randomly divided into 4 groups (n = 12): Group 1: control group, Group 2: reattachment followed by placement of two external vertical grooves on the labial surface and restored with polyethylene fibers and hybrid composite, Group 3: reattachment followed by two external vertical grooves and filled with fiber posts and composite, and Group 4: reattachment followed by circumferential chamfer at the fracture line and restored with composite. The forces required to fracture the reattached fragments were measured using a Universal testing machine. Data were analyzed using the Kruskal-Wallis test. Pairwise multiple comparison procedure was done using the Student-Newman-Keuls Method. RESULTS: The highest values for force required to fracture were observed in the fiber post group and the lowest in the Ribbond group (p < .05). The fiber post group had significantly different results compared to the Ribbond and Chamfer preparation groups (p < .05). However, the difference of rank between the fiber post and control groups was not significantly different (p > .05). CONCLUSION: The force required to fracture the fiber post group was closest to that of intact teeth followed by the chamfer and Ribbond groups, respectively.

Outcome of teeth restored with CAD/CAM zirconium dioxide post-cores: a retrospective study with a follow-up period of 3-6 years.

STATEMENT OF PROBLEM: Computer aided design/computer aided manufacturing (CAD/CAM) zirconia post-cores is one of the options of post crown restoration materials due to their esthetic properties and superior mechanical strength. However, the clinical effect on aesthetics and strength properties is unclear due to the lack of results of their long-term follow-up. PURPOSE: This retrospective clinical study aims to analyze the survival rate, clinical manifestations, and failure factors after CAD/CAM zirconia post-core restoration. MATERIAL AND METHODS: Clinical and radiographic examinations were performed on 342 patients with 400 teeth for 3-6 years postsurgical follow-up examination. The patients were all received CAD/CAM zirconia post-cores and all-ceramic crowns at the Department of Prosthodontics in the public hospital. The retrospective outcomes were conducted after zirconia post restoration, including survival rate by Kaplan-Meier analysis and findings of manifestations and failure factors. The effects of gender and dental position on survival rate were analyzed by Cox-Mantel Test. RESULTS: This study retrospectively evaluated 261 teeth from 229 patients with a 35% drop-out rate. The survival rate was 96.0%, and the success rate was 92.4%. According to the tooth position classification, the survival rate was 100% for 101 anterior teeth, 95.4% for 69 premolars, and 88.3% for 91 molars. According to gender, the survival rate of the male group was 92.3%, while that of the female group was 98.0%, with a significant difference (P < 0.01). The complications included crown fracture (1.9%) periapical inflammation (1.9%), crown debonding (1.1%), percussion abnormal (1.9%) and root fracture (0.8%). CONCLUSIONS: Within the limitations of this retrospective study, it can be concluded that CAD/CAM zirconia post-cores are clinically promising. Compared with the posterior teeth, CAD/CAM zirconia post-cores are more suitable for anterior teeth.

Restoration of teeth with customized CAD/CAM glass fiber posts: report of 2 cases.

This article presents 2 cases in which computer-aided design/computer-aided manufacturing (CAD/CAM) was used to fabricate glass fiber posts to restore an anterior tooth and a posterior tooth with severe coronal destruction. In the past decade, CAD/CAM technology has improved, allowing high-precision milling of customized glass fiber posts. This can enhance the biomechanical behavior of the restoration, as the post and core are milled in a single unit, decreasing the risk of failure near the core junction or in the body of the core. The customized post also provides better adaptation and requires a thinner layer of cement, thus minimizing voids. In case 1, the patient had a severely damaged maxillary right canine with a ferrule from a previous restoration. In case 2, the patient presented with a mandibular left first molar exhibiting severe coronal destruction. In both cases, impressions of the root canal were scanned with a bench scanner, and the posts were fabricated using a glass fiber material designed for CAD/CAM technology. A self-adhesive resin cement was used to cement the posts in the root canals, and a metal-free crown (case 1) and overlay (case 2) were fabricated and placed. Satisfactory retention and esthetics were achieved, and both patients was pleased by the final results. These cases demonstrate the viability of CAD/CAM to restore endodontically treated teeth, and this technology can be an option for dentists interested in using a digital workflow. The longevity of the posts produced via this technique needs to be evaluated in clinical trials.

Causal Effects of Alcohol-Related Facebook Posts on Drinking Behavior: Longitudinal Experimental Study.

BACKGROUND: Adolescents and young adults frequently post alcohol-related content (ie, alcoholposts) on social media. This is problematic because both social norms theory and social learning theory suggest that viewing alcoholposts of peers could increase drinking behavior. It is therefore paramount to understand the effects of exposure to alcoholposts on viewers. OBJECTIVE: This study aimed to investigate the causal effects of exposure to alcoholposts on alcohol consumption by using a rigorous design. METHODS: We conducted a 6-week longitudinal study during which alcoholposts were measured by a newly developed app that copied Facebook posts shared by participants (n=281) to a new social media environment. In addition, daily questionnaires assessed alcohol use. Effects of natural alcoholposts (ie, posted by the participants) were assessed in phase 1, and effects of experimental posts (ie, posted by fake participants) were explored in phase 2. RESULTS: Results showed that natural alcoholposts increased the occurrence and quantity of drinking the following day. That is, exposure to a single additional alcoholpost increased the log odds of drinking the next day by 0.27 (b=.27, credible interval [CI] .18 to .35). Furthermore, the number of natural alcoholposts had a positive (predictive) effect on the number of glasses drunk the next day (b=.21, CI .14 to .29). In phase 2 when experimental posts were also present, these effects decreased. Experimental posts themselves had hardly any effects. CONCLUSIONS: This study illustrates clear and direct effects of exposure to alcoholposts on next-day alcohol consumption and suggests that alcoholposts represent an important societal problem that interventions need to address.

Long-term costs of post-restorations: 7-year practice-based results from Germany.

OBJECTIVES: We evaluated the initial and follow-up treatment costs of different post-restorations in a practice-based German healthcare setting. METHODS: A total of 139 incisors, canines, or premolars received post-restorations placed by eight general dental practitioners in Germany, and were followed over a mean ± SD 7.1 ± 4.5 years. Preformed metal (MP, n = 68), glass-fiber (GF, n = 28), or cast post-and-core buildups (MC, n = 23) had been used to retain crowns or bridge anchors. Preformed metal and glass-fiber had also been used to retain directly built up post-retained composite restorations (PC, n = 20). Material and treatment costs for the initial post-restorations as well as restorative, endodontic, or surgical re-treatments were estimated from a public-payer-perspective in Germany. Associations between total and annualized total costs and covariates were assessed using generalized linear modeling. The study was registered in the German Clinical Trials Register (DRKS-ID: DRKS00012938). RESULTS: MC showed highest initial treatment costs (557.23 Euro), but the least re-treatments (6/23, 26%), while PC showed lowest initial costs (203.52 Euro) but the most re-treatments (11/20, 55%). Costs for MP/GF post-crowns were initially similarly costly (496.47/496.87 Euro), and both also showed similar re-treatments (35%/36%). The overall annual failure rate was 5.2% (MC: 3.5%, MP: 4.6%, GF: 5.3%, PC: 10.3%). Including costs for the resulting re-treatments, mean total costs were 591.66 Euro (MC), 548.31 Euro (MP), 526.37 Euro (GF), and 361.81 Euro (PC). Annualized total costs were 171.36 Euro (MC), 141.75 Euro (MP), 146.12 Euro (GF), and 135.65 Euro (PC). Total and annualized total costs were highest for MC, with PC being the significantly less costly option (p < 0.001). CONCLUSIONS: Within German healthcare, both initial and follow-up costs for post-restorations were considerable. Saving costs initially may, at least partially, be offset by more complications long-term. CLINICAL RELEVANCE: Dentists need to be aware that the placement of posts is not only initially costly but also comes with significant long-term costs for treating occurring complications. This should be communicated with patients and considered during treatment planning.