Evaluation of Load-bearing Capacity of Interim Fixed Partial Dentures Reinforced with Glass Fibers: An In Vitro Study.

AIM: To compare the load-bearing capacity of three and four-unit fixed partial denture (FPD) with two different designs of pontics reinforced with industrial glass fibers at two different positions of the FPD. MATERIALS AND METHODS: A total of 64 samples were made with Bis-acryl composite temporary material and reinforced with industrial glass fibers (E-glass). The specimens were divided into eight groups (groups I-VIII) depending on the number of units, type of pontic design and area of placement of fibers. A universal testing machine was used to evaluate and compare the load-bearing capacity of the specimens. The evaluated data were statistically analyzed using one-way ANOVA and Bonferroni post hoc tests (p ≤ 0.05). RESULTS: Three-unit interim FPD and modified ridge lap pontic design showed greater load-bearing capacity after reinforcement with glass fibers than a four-unit interim FPD and hygienic pontic design, respectively. Fiber placement at the occlusal plus connector area as well as the cervical plus connector area had comparable results. CONCLUSION: Industrial glass fibers (E-glass) could be used as a cheaper alternative but clinical performance and their safety are yet to be evaluated. CLINICAL SIGNIFICANCE: Reinforcement with industrial-grade glass fibers can be a cheaper option for increasing the load-bearing capacity of interim partial dentures, but it needs to be studied in vivo through further studies.

Sargassum polycystum and Turbinaria conoides Seaweed-based Novel Denture Cleanser: An In Vitro Study.

AIM: The study ventures into evaluating the antifungal and antibacterial efficacy of commercially available denture cleanser with Sargassum polycystum, Turbinaria conoides seaweeds, and the combination of seaweeds. MATERIALS AND METHODS: Poly(methyl methacrylate) disks measuring 10 × 2 mm were fabricated. The samples are divided into four groups of 21 samples each. The denture base was coated with Candida albicans and Streptococcus mutans individually. Group I was treated with Fittydent, group II (S. polycystum and T. conoides seaweeds combination), group III (S. polycystum), and group IV (T. conoides). The colony-formation units present on the surface of the denture were evaluated before and after treatment with different denture cleansers using the serial dilution method. Statistical analysis was done using descriptive statistics, analysis of variance, and post hoc Bonferroni analysis. RESULTS: At 10-5 dilution, T. conoides (group IV) was statistically significant in reducing both C. albicans and S. mutans. At 10-10 dilution, T. conoides (group IV) and S. polycystum and T. conoides combination (group II) had high antibacterial efficacy and were statistically significant. Fittydent (group I) had higher antifungal efficacy and was statistically significant in comparison to S. polycystum (group III) alone. At 10-10 dilution, the T. conoides (group IV), S. polycystum, and T. conoides combination (group II) showed no evidence of a significant difference in comparison to Fittydent (group I). Fittydent had higher antibacterial efficacy and was statistically significant in comparison to S. polycystum (group III) alone. CONCLUSION: Sargassum polycystum and T. conoides combination and T. conoides were found to have higher antibacterial efficacy in comparison to commercially available denture cleanser and also were found to have equal antifungal efficacy in comparison to commercially available denture cleanser.

Comparison of antifungal efficacy of commercially available denture cleanser and the extract of Turbinaria conoides seaweed against Candida albicans adherent to acrylic denture base resin: An in vitro study.

Aim: One of the main factors responsible for the development of Candida albicans on the surface of denture is improper maintenance of dentures. Denture hygiene can be achieved by regular cleansing of dentures using an appropriate denture cleanser. The aim of the study is to evaluate the antifungal efficacy of commercially available denture cleanser and the extract of Turbinaria conoides seaweed against C. albicans adherent to the surface of denture base resin. Settings and Design: This was an in vitro experimental study. Materials and Methods: Twenty-four Acrylic resin samples of dimension 10-mm radius and 2-mm thickness was randomly divided into two groups. The denture base resin was coated with C. albicans. The colonies present on the surface of each denture base resin were evaluated by serial dilution method. Group A was treated with commercially available denture cleanser and Group B was treated with extract of seaweed T. conoides. The colonies were then evaluated using serial dilution. Statistical Analysis Used: The colony count values obtained by serial dilution were tabulated. These values were statistically analysed using t-test. Results: Reduction of colony count is more in T. conoides than commercially available Fittydent; the difference was statistically significant with a mean difference of 65 at dilution 10-2 and 29.25 at dilution 10-3 using t-test with P < 0.001. Conclusion: Within the limitations of this in vitro study, it was proved that the extract of T. conoides seaweed and commercially available denture cleanser Fittydent was effective in reducing the colony count of C. albicans. T. conoides seaweed is statistically significant than commercially available Fittydent.

Comparative Analysis of Electric Field Strength, Magnetic Field Strength and Power Density around the Cell Phone Towers of Varying Characteristics with a Proposed Classification Facilitating Research on Human Population.

The continuous exposure of electromagnetic field (EMF) radiation from cell phone towers may possibly have an influence on public health. Each cell phone tower is unique in terms of number of antennas and its associated attributes; thus, the radiation exposure varies from one tower to another. Hence, a standardized method for quantifying the exposure is beneficial while studying the effects of radiation on the human population residing around the cell phone towers. A mere collection of data or human samples without understanding the cell phone tower differences may show study results such as an increase or decrease in biological parameters. Those changes may not be due to the effects of EMF radiation from cell phone towers but could be due to any other cause. Therefore, a comparative study was designed with the aim of quantifying and comparing the electric field strength (EF), magnetic field strength (MF) and power density (PD) on four sides of cell phone towers with varying numbers of antennas at 50 m and 100 m. Further, an attempt was made to develop a PD-based classification for facilitating research involving human biological samples. Through convenience sampling, sixteen cell phone towers were selected. With the use of coordinates, the geographic mapping of selected towers was performed to measure the distance between the towers. Based on the number of antennas, the cell phone towers were categorized into four groups which are described as group I with 1-5 antennas, group II comprising of 6-10 antennas, group III consisting of 11-15 antennas and group IV comprised of towers clustered with more than 15 antennas. The study parameters, namely the EF, MF and PD, were recorded on all four sides of the cell phone towers at 50 m and 100 m. One-way ANOVA was performed to compare the study parameters among study groups and different sides using the Statistical Package for the Social Sciences (SPSS) version 25.0. The mean MF in Group IV was 2221.288 ± 884.885 µA/m and 1616.913 ± 745.039 µA/m at 50 m and 100 m respectively. The mean PD in Group IV at 50 m was 0.129 ± 0.094 µW/cm2 and 0.072 ± 0.061 µW/cm2 at 100 m. There was a statistically significant (p < 0.05) increase in the MF and PD at 50 m compared to 100 m among cell phone tower clusters with more than 15 antennas (Group IV). On the other hand, a non-significant increase in EF was observed at 50 m compared to 100 m in Group II and IV. The EF, MF and PD on all four sides around cell phone towers are not consistent with distance at 50 m and 100 m due to variation in the number of antennas. Accordingly, a PD-based classification was developed as low, medium and high for conducting research involving any biological sample based on quantile. The low PD corresponds to 0.001-0.029, medium to 0.03-0.099 and high to 0.1-0.355 (µW/cm2). The PD-based classification is a preferred method over the sole criteria of distance for conducting human research as it measures the true effects of EMF radiation from the cell phone towers.

Evaluation of Bond Strength of Cantilever Resin-retained Bridge Designs: An In Vitro Study.

AIM: The aim of the study was to compare the bond strength of three cantilever resin-bonded bridge (RBB) designs cemented with resin cements. MATERIALS AND METHODS: Twenty-four extracted human mandibular canines with eight teeth per group were used in this study to evaluate the bond strength of cantilever resin-retained bridge designs of the mesh, perforated, and combination of mesh and perforated luted to the prepared lingual surface of canine teeth using resin cement. Debonding was done using Instron universal testing machine by applying load on the mid-buccal region of the pontic and the obtained values were evaluated. The data was analyzed statistically. RESULTS: The mean shear bond strengths of mesh, perforated, and combination of mesh and perforated are 0.88 ± 0.31 MPa, 0.81 ± 0.31 MPa, and 0.93 ± 0.32 MPa. However, there is no significant differences in the statistical analysis that were performed using a one-factor analysis of variant (ANOVA) test (p = 0.744). CONCLUSION: Within the limitation of this study for cantilever resin-retained bridge designs, the combination of mesh and perforated design showed greater mean shear bond values when compared with the mesh design and perforated designs. This shows equal in vitro performance to the gold standard designs (group A is mesh design and group B is perforated design). CLINICAL SIGNIFICANCE: The new design which is the combination of mesh and perforated shows equal in vitro performance to the gold standard designs. Thus, their use in clinical situation can bring better result in concern to cantilever resin-retained prosthesis.

Porewater salinity reveals past lake-level changes in Lake Van, the Earth's largest soda lake.

In closed-basin lakes, sediment porewater salinity can potentially be used as a conservative tracer to reconstruct past fluctuations in lake level. However, until now, porewater salinity profiles did not allow quantitative estimates of past lake-level changes because, in contrast to the oceans, significant salinity changes (e.g., local concentration minima and maxima) had never been observed in lacustrine sediments. Here we show that the salinity measured in the sediment pore water of Lake Van (Turkey) allows straightforward reconstruction of two major transgressions and a major regression that occurred during the last 250 ka. We observed strong changes in the vertical salinity profiles of the pore water of the uppermost 100 m of the sediments in Lake Van. As the salinity balance of Lake Van is almost at steady-state, these salinity changes indicate major lake-level changes in the past. In line with previous studies on lake terraces and with seismic and sedimentological surveys, we identify two major transgressions of up to +105 m with respect to the current lake level at about 135 ka BP and 248 ka BP starting at the onset of the two previous interglacials (MIS5e and MIS7), and a major regression of about -200 m at about 30 ka BP during the last ice age.

Global patterns in lake ecosystem responses to warming based on the temperature dependence of metabolism.

Climate warming is expected to have large effects on ecosystems in part due to the temperature dependence of metabolism. The responses of metabolic rates to climate warming may be greatest in the tropics and at low elevations because mean temperatures are warmer there and metabolic rates respond exponentially to temperature (with exponents >1). However, if warming rates are sufficiently fast in higher latitude/elevation lakes, metabolic rate responses to warming may still be greater there even though metabolic rates respond exponentially to temperature. Thus, a wide range of global patterns in the magnitude of metabolic rate responses to warming could emerge depending on global patterns of temperature and warming rates. Here we use the Boltzmann-Arrhenius equation, published estimates of activation energy, and time series of temperature from 271 lakes to estimate long-term (1970-2010) changes in 64 metabolic processes in lakes. The estimated responses of metabolic processes to warming were usually greatest in tropical/low-elevation lakes even though surface temperatures in higher latitude/elevation lakes are warming faster. However, when the thermal sensitivity of a metabolic process is especially weak, higher latitude/elevation lakes had larger responses to warming in parallel with warming rates. Our results show that the sensitivity of a given response to temperature (as described by its activation energy) provides a simple heuristic for predicting whether tropical/low-elevation lakes will have larger or smaller metabolic responses to warming than higher latitude/elevation lakes. Overall, we conclude that the direct metabolic consequences of lake warming are likely to be felt most strongly at low latitudes and low elevations where metabolism-linked ecosystem services may be most affected.

Diel Surface Temperature Range Scales with Lake Size.

Ecological and biogeochemical processes in lakes are strongly dependent upon water temperature. Long-term surface warming of many lakes is unequivocal, but little is known about the comparative magnitude of temperature variation at diel timescales, due to a lack of appropriately resolved data. Here we quantify the pattern and magnitude of diel temperature variability of surface waters using high-frequency data from 100 lakes. We show that the near-surface diel temperature range can be substantial in summer relative to long-term change and, for lakes smaller than 3 km2, increases sharply and predictably with decreasing lake area. Most small lakes included in this study experience average summer diel ranges in their near-surface temperatures of between 4 and 7°C. Large diel temperature fluctuations in the majority of lakes undoubtedly influence their structure, function and role in biogeochemical cycles, but the full implications remain largely unexplored.

Global impacts of the 1980s regime shift.

Despite evidence from a number of Earth systems that abrupt temporal changes known as regime shifts are important, their nature, scale and mechanisms remain poorly documented and understood. Applying principal component analysis, change-point analysis and a sequential t-test analysis of regime shifts to 72 time series, we confirm that the 1980s regime shift represented a major change in the Earth's biophysical systems from the upper atmosphere to the depths of the ocean and from the Arctic to the Antarctic, and occurred at slightly different times around the world. Using historical climate model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) and statistical modelling of historical temperatures, we then demonstrate that this event was triggered by rapid global warming from anthropogenic plus natural forcing, the latter associated with the recovery from the El Chichón volcanic eruption. The shift in temperature that occurred at this time is hypothesized as the main forcing for a cascade of abrupt environmental changes. Within the context of the last century or more, the 1980s event was unique in terms of its global scope and scale; our observed consequences imply that if unavoidable natural events such as major volcanic eruptions interact with anthropogenic warming unforeseen multiplier effects may occur.

Finding revelation in anthropology: Alexander Winchell, William Robertson Smith and the heretical imperative.

Anthropological inquiry has often been considered an agent of intellectual secularization. Not least is this so in the sphere of religion, where anthropological accounts have often been taken to represent the triumph of naturalism. This metanarrative, however, fails to recognize that naturalistic explanations could sometimes be espoused for religious purposes and in defence of confessional creeds. This essay examines two late nineteenth-century figures--Alexander Winchell in the United States and William Robertson Smith in Britain--who found in anthropological analysis resources to bolster rather than undermine faith. In both cases these individuals found themselves on the receiving end of ecclesiastical censure and were dismissed from their positions at church-governed institutions. But their motivation was to vindicate divine revelation, in Winchell's case from the physical anthropology of human origins and in Smith's from the cultural anthropology of Semitic ritual.

Double frenum weds fusion: a rare wedlock?

Morphological variation of normal oral structures such as double frenum and fusion together in a patient is rare. Sometimes such scenarios may mislead the diagnosis, affecting treatment planning and prognosis. Hence a thorough evaluation of patients with such morphological defects is necessary. This case report describes a case of double frenum and fusion, and the multiple challenges the clinician faces.

A global database of lake surface temperatures collected by in situ and satellite methods from 1985-2009.

Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear. Thus, a global data set of water temperature is required to understand and synthesize global, long-term trends in surface water temperatures of inland bodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collected in situ and/or by satellites for the period 1985-2009. In addition, corresponding climatic drivers (air temperatures, solar radiation, and cloud cover) and geomorphometric characteristics (latitude, longitude, elevation, lake surface area, maximum depth, mean depth, and volume) that influence lake surface temperatures were compiled for each lake. This unique dataset offers an invaluable baseline perspective on global-scale lake thermal conditions as environmental change continues.

Prosthodontic rehabilitation of a patient with aggressive periodontitis.

Aggressive periodontitis previously termed as juvenile periodontitis is characterised by rapid destruction of the periodontium at a relatively young age. Rehabilitation of these patients is often challenging and difficult. Controlling the disease and restoring periodontal health is essential for successful prosthodontic rehabilitation. This clinical report describes an interdisciplinary approach in the rehabilitation of a young adult patient with generalised aggressive periodontitis. Treatment objectives included plaque control, prevention of further attachment loss, reduction/elimination of pockets, and prosthetic rehabilitation to enhance aesthetics and restore masticatory function. One year recall evaluation revealed stable periodontal support with no further loss of attachment and no other complications.

Science-policy processes for transboundary water governance.

In this policy perspective, we outline several conditions to support effective science-policy interaction, with a particular emphasis on improving water governance in transboundary basins. Key conditions include (1) recognizing that science is a crucial but bounded input into water resource decision-making processes; (2) establishing conditions for collaboration and shared commitment among actors; (3) understanding that social or group-learning processes linked to science-policy interaction are enhanced through greater collaboration; (4) accepting that the collaborative production of knowledge about hydrological issues and associated socioeconomic change and institutional responses is essential to build legitimate decision-making processes; and (5) engaging boundary organizations and informal networks of scientists, policy makers, and civil society. We elaborate on these conditions with a diverse set of international examples drawn from a synthesis of our collective experiences in assessing the opportunities and constraints (including the role of power relations) related to governance for water in transboundary settings.

Sharp tooth induced sublingual hematoma in a patient with elevated international normalized ratio.

Sublingual hematoma secondary to anticoagulation is a rare fatal condition. Hemorrhagic complications of warfarin are well-known. This particular case is unique because the patient was on warfarin for the past 2 years but did not develop the sublingual hematoma. However, a trauma by an attrited sharp cusp triggered the episode of the sublingual hematoma in this patient. Being a medical emergency, patient was promptly hospitalized in cardiac care unit and managed by medical team. The patient was transfused with 2 units of fresh frozen plasma and warfarin was temporarily stopped for 4 days. Alternate day regimen of warfarin was started after 4 days, and international normalized ratio dropped to 3. In dental management, enameloplasty of the mandibular first molar tooth was done to prevent trauma and ulcer development in the floor of the mouth. The hematoma resolved, and no new hematoma formation was observed for a period of 6 months.

Evaluation of Crestal Bone Loss Around Implants Placed at Equicrestal and Subcrestal Levels Before Loading: A Prospective Clinical Study.

INTRODUCTION: Depth of placement of implant shoulder in relation to the crestal bone positively influence bone remodelling and preservation but the role of placement depth on bone loss before loading is not very clear. AIM: To assess the effect of placement depth alone on the crestal bone loss around implant placed at subcrestal and equicrestal level before prosthetic loading. MATERIALS AND METHODS: Patients reporting to the Department of Prosthodontics with the complaint of missing teeth were enrolled in the study after analysing inclusion and exclusion criteria. A total of 24 implants were planned to be placed into two groups as Group E (n=12) and Group S (n=12). Follow up radiographs after implant placement and after six months were analysed for the amount of bone loss. RESULTS: On six months follow up crestal bone levels of Group E were apical to Group S. Bone loss comparison between groups after six months follow up, revealed almost same mean bone loss. CONCLUSION: The implants placed at subcrestal and equicrestal level did not show difference in crestal bone loss before prosthetic loading.

Forecasting Groundwater Temperature with Linear Regression Models Using Historical Data.

Although temperature is an important determinant of many biogeochemical processes in groundwater, very few studies have attempted to forecast the response of groundwater temperature to future climate warming. Using a composite linear regression model based on the lagged relationship between historical groundwater and regional air temperature data, empirical forecasts were made of groundwater temperature in several aquifers in Switzerland up to the end of the current century. The model was fed with regional air temperature projections calculated for greenhouse-gas emissions scenarios A2, A1B, and RCP3PD. Model evaluation revealed that the approach taken is adequate only when the data used to calibrate the models are sufficiently long and contain sufficient variability. These conditions were satisfied for three aquifers, all fed by riverbank infiltration. The forecasts suggest that with respect to the reference period 1980 to 2009, groundwater temperature in these aquifers will most likely increase by 1.1 to 3.8 K by the end of the current century, depending on the greenhouse-gas emissions scenario employed.

Effect of four surface treatment methods on the shear bond strength of resin cement to zirconia ceramics- a comparative in vitro study.

BACKGROUND: Improving the retention of zirconia-based ceramics is desirable in order to avoid the failure of crowns and fixed partial dentures .This can be achieved by creating micromechanical retention using surface treatments. Therefore, it becomes necessary to constantly compare and re-evaluate the influence of different surface treatment methods on the bond strength . AIM: To evaluate the effect of four different surface treatments on shear bond strength between zirconia surface and resin cements. SETTINGS AND DESIGN: Observational study. MATERIALS AND METHODS: Twenty five zirconia plate samples were prepared based on ISO standards and were divided into five groups and each group was subjected to following five different surface treatments : no treatment, sandblasting with 110 µm alumina, sandblasting with 250 µm alumina, acid etching with 9.6% hydrofluoric acid and laser radiation on the surface. All the samples were surface disinfected and were embedded in blocks of autopolymerising resin to check shear bond strength on the universal testing machine. Statistical analysis used-data was analyzed using one-way ANOVA and a Post Hoc Bonferroni test. RESULTS: Analysis of the data showed that the highest shear bond strength values were obtained with laser treatment (18.120 ± 0.8159 Mpa). The lowest values were obtained with control group (9.166 ± 0.569 Mpa). Laser treatment increased the shear bond strength values significantly (p<0.05). CONCLUSION: Surface treatments increased the bond strength between zirconia and resin cement and carbon dioxide laser could be an effective surface treatment for increasing bond strength.

Prosthetic rehabilitation of palatal perforation in a patient with 'syphilis: the great imitator'.

Syphilis is a sexually transmissible disease caused by treponema palladium, a microaerophilic spirochete. Syphilis may progress from primary to tertiary stage if left unnoticed and untreated. Dentists should be vigilant and suspect sexually transmitted infections such as syphilis in the differential diagnosis of oral inflammatory or ulcerative lesions with palatal perforation. Moreover, it is imperative that dentists should have knowledge about its stages, characteristic features, oral presentation and prosthetic rehabilitation. This case report describes a case of tertiary syphilis with palatal perforation and the prosthetic rehabilitation of the defect with a prosthetic obturator.