Assessment of occlusion changes during laboratory phase of relining: An in vitro study.

AIM: Assessment of occlusion changes during laboratory phase of relining is essential to evaluate the occlusal discrepancies that could get incorporated in the denture with the use of different relining materials. Since the long term stability and functional success of the denture is heavily influenced by occlusion, an In-vitro study to assess these changes after relining is warranted. The aim of the study is to evaluate the changes in occlusion during laboratory phase of relining procedure. SETTINGS AND DESIGN: This is an in vitro study with a total of 30 specimen. MATERIALS AND METHODOLOGY: A total of 30 maxillary standardized dentures were fabricated after mounting on a semi adjustable articulator. These samples will be divided into three groups based on the relining material used (Autopolymerizing resin, Heat-cure resin, Tissue conditioner). The vertical dimension, Centric contact points and eccentric contact points were measured before and after relining. STATISTICAL ANALYSIS USED: The variables were tested to see if they had a normal distribution using the Shapiro-Wilk test. Parametric distribution was seen for ECP leading to further comparison using one way analysis of variance (ANOVA). Non-parametric distribution was found while testing the VD, CCP leading to adoption of Kruskal-wallis test for comparison of groups. Dunn Bonferroni test was done for VD since results were significant. RESULTS: The results of this in-vitro study showed statistically significant difference with respect to change in vertical dimension in all groups pre and post relining (P = 0.005). The centric contact points showed lesser variation in position when comparing the pre to the post relining phase with the use of autopolymerising resins, whereas heat cure resins and tissue conditioners showed statistically significant difference in the centric point contacts post relining. No statistically significant changes were seen in eccentric occlusion post relining in all groups. Tissue conditioners showed minimum mean changes in eccentric contacts. CONCLUSION: Within the limitations of this study, the use of autopolymerising resins depicted the most stable results with respect to occlusion, for relining of dentures.

Silver doped barium titanate nanoparticles for enhanced visible light photocatalytic degradation of dyes.

Due to the rapid growth of global population, new, fast and reliable methods must be developed to purify contaminated water. Various photocatalysts have been developed to remove organic dyes from water. Herein, Ag doped BaTiO3 has been synthesized using a facile solvothermal method and its excellent photocatalytic activities were demonstrated in degradation of both anionic and cationic dyes under visible light illumination. Ag doped BaTiO3 nanoparticles showed greater efficacy in the degradation of methylene blue (MB) and eosin yellow (EY) than undoped BaTiO3 nanoparticles, which makes them a better candidate for photocatalysis. 1.0 AgBT sample showed the highest photocatalytic activity for MB (99.1 % in 100 min) and EY (99.3 % in 60 min) dye degradation compared with those of other samples. Further, the trapping experiments revealed that hydroxyl radicals and holes are the active species in the photocatalytic process of MB and EY dye degradation and recycle test showed excellent stability of the synthesized material.

A Comparison of Occlusal Schemes with Condylar Inclination and Anterior Guidance in Dentate Individuals.

PURPOSE: A Comparison of Occlusal Schemes with Condylar Inclination and Anterior Guidance in Dentate Individuals Methods. Twenty-six dentate patients between the ages of 18 to 30 of Indian Origin with canine-guided occlusion and 26 patients with group function occlusion were included in the study. The School of Articulator Munich (SAM) Axioquick system was used to assess the condylar guidance and eccentric tracings of the patients. For analyses, Student's t-test was used. For quantitative data, the mean and standard deviation were calculated. For all the statistical analysis the probability of type-I error of 0.05 was considered statistically significant. RESULTS: The mean condylar guidance for canine guided and group function occlusion on the right side was 38.4 ±12.7 and 30.5 ±12.5 and on the left side was 36.5 ±13.0 and 27.5±12.0 degrees with statistically significant difference [P value: 0.01]. The condylar guidance, incisal guidance, Bennett angle, protrusion, left lateral, right lateral, and left and right lateral angles were analyzed statistically between the two types of occlusions. The results showed a statistically significant difference between the two groups for all parameters except right condylar guidance. Furthermore, all the parameters were higher in canine guided occlusion group over group function occlusion. CONCLUSIONS: Within the study limitations, it was concluded that the condylar guidance was steeper in canine guided occlusion than in group function occlusion. The eccentric parameters were steeper in canine guided occlusion than in group function occlusion. CLINICAL SIGNIFICANCE: This study showcases that the condylar guidance might not play a major role in determining the occlusal scheme but, the incisal guidance determines the occlusal scheme predominantly in class 1 occlusion patients.

Exposure of combination of environmental pollutant, lead (Pb) and ß-amyloid peptides causes mitochondrial dysfunction and oxidative stress in human neuronal cells.

Exposure to the environmental pollutant lead (Pb) has been linked to Alzheimer's disease (AD), in which mitochondrial dysfunction is a pathological consequence of neuronal degeneration. The toxicity of Pb in combination with ß-amyloid peptides (1-40) and (25-35) causes selective death in neuronal cells. However, the precise mechanism through which Pb induces Alzheimer's disease, particularly mitochondrial damage, is unknown. Changes in mitochondrial mass, membrane potential, mitochondrial complex activities, mitochondrial DNA and oxidative stress were examined in neuronal cells of human origin exposed to Pb and ß-amyloid peptides (1-40) and (25-35) individually and in different combinations. The results showed depolarization of mitochondrial membrane potential, decrease in mitochondrial mass, ATP levels and mtDNA copy number in Pb and ß-amyloid peptides (1-40) and (25-35) exposed cells. Also, significant reductions in the expression of mitochondrial electron transport chain (ETC) complex proteins (ATP5A, COXIV, UQCRC2, SDHB, NDUFS3), as well as down regulation of ETC complex gene expressions such as COXIV, ATP5F1 and NDUFS3 and antioxidant gene expressions like MnSOD and Gpx4 were observed in exposed cells. Furthermore, Pb and ß-amyloid peptides exposure resulted in elevated mitochondrial malondialdehyde levels and a decrease in mitochondrial GSH levels. Our findings suggest that Pb toxicity could be one of the causative factors for the mitochondrial dysfunction and oxidative stress in Alzheimer's disease progression.

Five-Minute Magnetic Nanoparticle Spectroscopy-Based Bioassay for Ultrafast Detection of SARS-CoV-2 Spike Protein.

In this work, we report a 5-min magnetic particle spectroscopy (MPS)-based bioassay strategy. In our approach, surface-functionalized magnetic nanoparticles are incubated with target analytes at 37 °C with agitation for 3 min, and the MPS reading is then taken at the fifth minute. We prove the feasibility of 5 min ultrafast detection of SARS-CoV-2 spike protein with a detection limit below 5 nM (0.2 pmol). Our proposed 5-min bioassay strategy may be applied to reduce the assay time for other liquid-phase, volumetric biosensors such as NMR, quantum dots, fluorescent biosensors, etc.

Role of water structure in alkaline water electrolysis.

Herein, with the help of experimental and first-principles density functional theory (DFT)-based studies, we have shown that structural changes in the water coordination in electrolytes having high alkalinity can be a possible reason for the reduced catalytic activity of platinum (Pt) in high pH. Studies with polycrystalline Pt electrodes indicate that electrocatalytic HER activity reduces in terms of high overpotential required, high Tafel slope, and high charge transfer resistances in concentrated aqueous alkaline electrolytes (say 6 M KOH) in comparison to that in low alkaline electrolytes (say 0.1 M KOH), irrespective of the counter cations (Na+, K+, or Rb+) present. The changes in the water structure of bulk electrolytes as well as that in electrode-electrolyte interface are studied. The results are compared with DFT-based analysis, and the study can pave new directions in studying the HER process in terms of the water structure near the electrode-electrolyte interface.

Realizing 1,1-Dehydration of Secondary Alcohols to Carbenes: Pyrrolidin-2-ols as a Source of Cyclic (Alkyl)(Amino)Carbenes.

Herein we report secondary pyrrolidin-2-ols as a source of cyclic (alkyl)(amino)carbenes (CAAC) for the synthesis of CAAC-CuI -complexes and cyclic thiones when reacted with CuI -salts and elemental sulfur, respectively, under reductive elimination of water from the carbon(IV)-center. This result demonstrates a convenient and facile access to CAAC-based CuI -salts, which are well known catalysts for different organic transformations. It further establishes secondary alcohols to be a viable source of carbenes-realizing after 185 years Dumas' dream who tried to prepare the parent carbene (CH2 ) by 1,1-dehydration of methanol. Addressed is also the reactivity of water towards CAACs, which proceeds through an oxidative addition of the O-H bond to the carbon(II)-center. This emphasizes the ability of carbon-compounds to mimic the reactivity of transition-metal complexes: reversible oxidative addition and reductive elimination of the O-H bond to/from the C(II)/C(IV)-centre.

Evaluating the Impact of Intraoperative MRI in Neuro-Oncology by Scientometric Analysis.

(1) Objective-Intraoperative Magnetic Resonance Imaging (IOMRI) guided surgery has revolutionized neurosurgery and has especially impacted the field of Neuro-Oncology, with randomized controlled trails demonstrating improved resection, fewer postoperative deficits and enhanced survival rates. Bibliometric analysis allows for analysing chronological trends and measuring the impact and directions of research in a particular field. To the authors' knowledge, this is the first Bibliometric analysis conducted on IOMRI. (2) Methods-a title specific search of the Web of Science database was executed using the keywords 'intraoperative MRI', 'intraoperative magnetic resonance imaging', and "IOMRI' on 23rd April 2021. Results-663 articles met the inclusion criteria and were included in the final analysis. In addition, the 100 most cited were analysed as well. Among these 100 articles, 76 were original research papers, while 14 others were review articles. Amongst all the authors, Ganslandt contributed the maximum number of articles, with USA being the largest single source of these articles, followed by Germany. Interestingly, a shift of trends from "Image guided surgery' and 'accuracy' in the early 2000s to 'extent of resection', 'impact', and 'survival' in the later years was noted. (3) Conclusions-IOMRI has now become an integral part of neurosurgery, especially in neuro-oncology. Focus has now shifted from implementation to refinement of technique in the form of functional and oncological outcomes. Therefore, future research in this direction is imperative and will be of more impact that in any other sub-field related to IOMRI.

Virtual Reality in Neurosurgery: Beyond Neurosurgical Planning.

BACKGROUND: While several publications have focused on the intuitive role of augmented reality (AR) and virtual reality (VR) in neurosurgical planning, the aim of this review was to explore other avenues, where these technologies have significant utility and applicability. METHODS: This review was conducted by searching PubMed, PubMed Central, Google Scholar, the Scopus database, the Web of Science Core Collection database, and the SciELO citation index, from 1989-2021. An example of a search strategy used in PubMed Central is: "Virtual reality" [All Fields] AND ("neurosurgical procedures" [MeSH Terms] OR ("neurosurgical" [All Fields] AND "procedures" [All Fields]) OR "neurosurgical procedures" [All Fields] OR "neurosurgery" [All Fields] OR "neurosurgery" [MeSH Terms]). Using this search strategy, we identified 487 (PubMed), 1097 (PubMed Central), and 275 citations (Web of Science Core Collection database). RESULTS: Articles were found and reviewed showing numerous applications of VR/AR in neurosurgery. These applications included their utility as a supplement and augment for neuronavigation in the fields of diagnosis for complex vascular interventions, spine deformity correction, resident training, procedural practice, pain management, and rehabilitation of neurosurgical patients. These technologies have also shown promise in other area of neurosurgery, such as consent taking, training of ancillary personnel, and improving patient comfort during procedures, as well as a tool for training neurosurgeons in other advancements in the field, such as robotic neurosurgery. CONCLUSIONS: We present the first review of the immense possibilities of VR in neurosurgery, beyond merely planning for surgical procedures. The importance of VR and AR, especially in "social distancing" in neurosurgery training, for economically disadvantaged sections, for prevention of medicolegal claims and in pain management and rehabilitation, is promising and warrants further research.

A Comparative Scientometric Analysis of the 100 Most Cited Articles of Acta Neurochirurgica (Wien) and World Neurosurgery.

BACKGROUND: Acta Neurochirurgica (ANCH) and World Neurosurgery (WN), are 2 journals of significant importance in the neurosurgical community and have been associated with international federations. These journals carry a similar impact factor. The difference is the years they have been active (ANCH starting publication in 1973 and WN in 2010). This factor allows for a unique opportunity to delve deep into comparative, scientometric parameters, to understand the evolution of neurosurgical research. METHODS: A title-specific search of the Web of Science database using the keywords "Acta Neurochirurgica," "Acta," "Neurochirurgica," "World Neurosurgery," "World," and "Neurosurgery" was performed and arranged according to number of citations. The title of the articles, authors, corresponding authors, country of origin, journal of publication, year of publication, citation count. and journal impact factor were assessed. RESULTS: The average citation for ANCH was 170.1 citations, most being original articles (83/100). The articles of WN garnered nearly 70.48 citations, averaging 8.3 citations per publication. Most corresponding authors in ANCH originated from Germany with neuro-oncology, followed by neurotrauma and vascular as subjects. In contrast, the United States followed by China were the most common countries of origin for WN, with endoscopy and skull base being the topics achieving high impact. CONCLUSIONS: Neurotrauma and consensus guidelines have been shown to have maximal citations for ANCH whereas endoscopy and skull base lesions garnered the most for WN. Author subspecialization and increased collaboration across specialties with more articles on refinement of technique and outcome have emerged as recent trends.

Patients With Suicidal Patterns in the Emergency Room: A Clinical and Social Reflection.

Background and objective Emergency physicians come across a myriad of medical afflictions resulting from suicide attempts. The Indian contribution to global suicide deaths is alarming; the social construct of India is unique, and so are the problems and challenges. This study aims to describe the social background, demographic parameters and correlate the clinical profile and outcomes of all patients presenting with an attempted or completed suicide. Materials and methods The present study is a hospital-based prospective observational study conducted by the Department of Emergency Medicine at RL Jalappa Hospital and Research Centre, a rural tertiary-care center in Karnataka, India, from June 2020 to February 2021. After stabilizing the patient, a detailed socio-demographic history was recorded. Details of the suicide attempt and findings of the clinical examination were noted. Results The final study sample consisted of 89 patients who presented to the emergency room (ER). Fifty-three patients were female, and thirty-six were males; the average age of the sample was 28.4 ± 11 years. A higher proportion of men who completed pre-university education (p= 0.0005, c2= 11.98) or had a graduate degree (p= 0.009, c2= 6.71) attempted suicide. Amongst all women who attempted suicide, 73.6% (n=39) were married at the time of the event (p= 0.0006, c2= 11.79). Poisoning (n=59) was the most common method of attempting suicide. We also observed that it was primarily men who attempted suicide when under the influence of alcohol (p= 0.006, c2= 7.57). The most common reason for attempting suicide was familial disharmony, including domestic violence. A Glasgow Coma Scale (GCS) score of 9/15 and less at the time of presentation resulted in a mortality rate of 28.6%, whereas patients with a GCS score of 10 and above had a mortality rate of 6.1% (p= 0.04, c2= 4.14). Discussion Marriage appears to be less protective for Indian women than Indian men. Poisoning was the most common method of attempted suicide in our study, followed by tablet overdose. The reason for the above could be ease of access to household poisons. Insecticides have been a preferred method in the Indian population over the years. Aluminum phosphide poisoning, a common constituent of rodenticides, is associated with a high mortality rate. However, in the West, firearm-related incidents have the highest mortality. Multiple correspondence analysis (MCA) of the National Crime Records Bureau (NCRB), India, data showed that adult males succumb majorly to romantic relations, unemployment, and failure in examinations. The use of alcohol was more in the illiterate and unskilled workers; however, high school educated persons and students used alcohol intentionally to facilitate suicide. Lower Glasgow Coma Scale values are associated with higher fatality; however, some studies found that Full Outline of Unresponsiveness (FOUR) and Acute Physiology and Chronic Health Evaluation Score (APACHE) II scores are better mortality indicators. Conclusion Besides the presentation and GCS score, cognizance of the lethality of different methods in attempting suicide provides clues in anticipating the patient's clinical course. The social patterns of suicide must be considered while designing awareness campaigns and focused outreach programs to decrease suicides. A strict policy must be made and enforced to limit the availability of household poisons.

One-Step, Wash-free, Nanoparticle Clustering-Based Magnetic Particle Spectroscopy Bioassay Method for Detection of SARS-CoV-2 Spike and Nucleocapsid Proteins in the Liquid Phase.

With the ongoing global pandemic of coronavirus disease 2019 (COVID-19), there is an increasing quest for more accessible, easy-to-use, rapid, inexpensive, and high-accuracy diagnostic tools. Traditional disease diagnostic methods such as qRT-PCR (quantitative reverse transcription-PCR) and ELISA (enzyme-linked immunosorbent assay) require multiple steps, trained technicians, and long turnaround time that may worsen the disease surveillance and pandemic control. In sight of this situation, a rapid, one-step, easy-to-use, and high-accuracy diagnostic platform will be valuable for future epidemic control, especially for regions with scarce medical resources. Herein, we report a magnetic particle spectroscopy (MPS) platform for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) biomarkers: spike and nucleocapsid proteins. This technique monitors the dynamic magnetic responses of magnetic nanoparticles (MNPs) and uses their higher harmonics as a measure of the nanoparticles' binding states. By anchoring polyclonal antibodies (pAbs) onto MNP surfaces, these nanoparticles function as nanoprobes to specifically bind to target analytes (SARS-CoV-2 spike and nucleocapsid proteins in this work) and form nanoparticle clusters. This binding event causes detectable changes in higher harmonics and allows for quantitative and qualitative detection of target analytes in the liquid phase. We have achieved detection limits of 1.56 nM (equivalent to 125 fmole) and 12.5 nM (equivalent to 1 pmole) for detecting SARS-CoV-2 spike and nucleocapsid proteins, respectively. This MPS platform combined with the one-step, wash-free, nanoparticle clustering-based assay method is intrinsically versatile and allows for the detection of a variety of other disease biomarkers by simply changing the surface functional groups on MNPs.

Spontaneous and frequent conformational dynamics induced by A A mismatch in d(CAA)·d(TAG) duplex.

Base pair mismatches in DNA can erroneously be incorporated during replication, recombination, etc. Here, the influence of A…A mismatch in the context of 5'CAA·5'TAG sequence is explored using molecular dynamics (MD) simulation, umbrella sampling MD, circular dichroism (CD), microscale thermophoresis (MST) and NMR techniques. MD simulations reveal that the A…A mismatch experiences several transient events such as base flipping, base extrusion, etc. facilitating B-Z junction formation. A…A mismatch may assume such conformational transitions to circumvent the effect of nonisostericity with the flanking canonical base pairs so as to get accommodated in the DNA. CD and 1D proton NMR experiments further reveal that the extent of B-Z junction increases when the number of A…A mismatch in d(CAA)·d(T(A/T)G) increases (1-5). CD titration studies of d(CAA)·d(TAG)n=5 with the hZαADAR1 show the passive binding between the two, wherein, the binding of protein commences with B-Z junction recognition. Umbrella sampling simulation indicates that the mismatch samples anti…+ syn/+ syn…anti, anti…anti & + syn…+ syn glycosyl conformations. The concomitant spontaneous transitions are: a variety of hydrogen bonding patterns, stacking and minor or major groove extrahelical movements (with and without the engagement of hydrogen bonds) involving the mismatch adenines. These transitions frequently happen in anti…anti conformational region compared with the other three regions as revealed from the lifetime of these states. Further, 2D-NOESY experiments indicate that the number of cross-peaks diminishes with the increasing number of A…A mismatches implicating its dynamic nature. The spontaneous extrahelical movement seen in A…A mismatch may be a key pre-trapping event in the mismatch repair due to the accessibility of the base(s) to the sophisticated mismatch repair machinery.

Vanadium doped CaTiO3 cuboids: role of vanadium in improving the photocatalytic activity.

CaTiO3 has attracted enormous interest in the fields of photocatalytic dye degradation and water splitting owing to its low cost, excellent physicochemical stability and structural tunability. Herein, we have developed a simple one pot solvothermal approach which directs V into the Ti sites in the isovalent state during the synthesis of V doped CaTiO3 cuboids. The prediction of reduction in the band gap due to the formation of additional levels just beneath the conduction band edge by the first principles density functional electronic structure study is confirmed by the experimental results. The suppression of charge carrier recombination in 1.0 V leads to the highest photocatalytic activity in the degradation of methylene blue. The percentage degradation of 94.2 indicates its suitability as an excellent catalyst for photocatalytic water treatment.

Cryo vs Thermo: Duality of Ethylene Glycol on the Stability of Proteins.

Osmolytes are known to stabilize proteins under stress conditions. Thermal denaturation studies on globular proteins (ß-lactoglobulin, cytochrome c, myoglobin, α-chymotrypsin) in the presence of ethylene glycol (EG), a polyol class of osmolyte, demonstrate a unique property of EG. EG stabilizes proteins against cold denaturation and destabilizes them during heat-induced denaturation. Further, chemical denaturation experiments performed at room temperature and at a sub-zero temperature (-10 °C) show that EG stabilizes the proteins at subzero temperature but destabilizes them at room temperature. The experiments carried out in the presence of glycerol, however, showed that glycerol stabilizes proteins against all of the denaturing conditions. This differential effect has not been reported for any other polyol class of osmolyte and might be specific to EG. Moreover, molecular dynamics simulations of all of the four proteins were carried out at three different temperatures, 240, 300, and 340 K, in the absence and presence of EG (20 and 40%). The results suggest that EG preferably accumulates around the hydrophobic residues and reduces the hydrophobic hydration of the proteins at a low temperature leading to stabilization of the proteins. At 340 K, the preferential hydration of the proteins is significantly reduced and the preferential binding of EG destabilizes the proteins like common denaturants.

α,α'-Diamino-p-quinodimethanes with Three Stable Oxidation States.

Herein, we report the rational design, synthesis, and characterization of α,α'-diamino-substituted-p-quinodimethanes, which are a group of partially substituted p-quinodimethanes. These exhibit two reversible one-electron redox steps and electrochromism in the ultraviolet, visible, and near-infrared regions. We were able to isolate the crystalline compounds of all three oxidation states: neutral, radical cation, and dication. The obtained results not only create the bridge between p-quinodimethane and α,α,α',α'-tetrasubstituted-p-quinodimethane, but also demonstrate the straightforward modular approach for the synthesis of π-conjugated open-shell compounds.

A porous graphene-NiFe2O4 nanocomposite with high electrochemical performance and high cycling stability for energy storage applications.

It is well agreed that supercapacitors form an important class of energy storage devices catering to a variety of needs. However, designing the same using eco-friendly and earth abundant materials with high performance is still the dire need of the day. Here, we report a facile solvothermal synthesis of a porous graphene-NiFe2O4 (PGNF) nanocomposite. Thorough elemental, diffraction, microscopic and spectroscopic studies confirmed the formation of the PGNF composite, in which the NF nanoparticles are covered over the PG surface. The obtained 10 PGNF composite showed a surface area of 107 m2 g-1, with large pore volume which is favorable for charge storage properties. When utilizing the material as an electrode for a supercapacitor in a 2 M KOH aqueous electrolyte, the electrode displayed an impressive specific capacitance value of 1465.0 F g-1 at a scan rate of 5 mV s-1 along with a high capacitance retention of 94% after 10 000 discharge cycles. The fabricated symmetrical supercapacitor device exhibited an energy density of 4.0 W h kg-1 and a power density of 3600.0 W kg-1 at a high applied current density of 14 A g-1. The superior electrochemical performance is attributed to the synergetic effect of the composite components which not only provided enough electroactive channels for the smooth passage of electrolyte ions but also maintained the hybrid structure intact in the ongoing electrochemical process. The obtained results underpin the promising utility of this material for future electrochemical energy storage devices.

Rhodium doping augments photocatalytic activity of barium titanate: effect of electronic structure engineering.

Environmentally friendly BaTiO3 is emerging as a potential photocatalyst due to its tunable electronic structure. Although originally believed to be a poor photocatalyst due to its wide band gap, several strategies have been implemented to reduce its band gap. One such approach is doping, but this often leads to the formation of mid gap recombination centers and diminishes the efficiency of the material. In the present work, we study for the first time the effect of site occupancy of Rh on the electronic structure of BaTiO3. As the theoretical results reveal that if Rh occupies both Ba and Ti sites simultaneously it leads to the formation of mid gap states, an experimental approach is implemented to reduce the band gap of BaTiO3 while simultaneously avoiding the formation of recombination centers. The facile one pot hydrothermal approach reported here directs the Rh towards Ba sites leading to a decrease in the band gap due to the appearance of donor Rh3+ states, suppressing the formation of Rh4+ states. A promising photocatalytic activity of 96% degradation of methylene blue dye in 120 minutes was observed for the 0.5 Rh sample indicating the high efficiency of the material.

A comparison between visual, digital photography and polarizing filter photography for shade selection.

AIM: There is an increased awareness for aesthetically pleasing restorations among patients in current practice. Due to variability in the natural tooth colour, shade selection becomes an intricate procedure. The aim of this study is to determine which of the three named methods is more accurate for shade selection in aesthetic dentistry. MATERIALS AND METHODS: Two VITAPAN classical shade guides were used for this study. Nine shades were selected from the first shade guide (A1, A2, A3.5, B1, B2, B3, C1, C2, C3) and the number was concealed. Ten selected participants were asked to identify each concealed shade with the second shade guide. Canon 5D camera with ISO 200, shutter speed 1/100 sec, F22 was used for capturing images of the second shade guide. Photoshop CS3 Software was used for developing the digital shade guide. The participants were asked to match the shades from the first shade guide with the prepared digital shade guide. The third photographic shade guide was prepared using a polarised filter on the Canon 5D camera with the same settings. The participants were asked to match shades with the prepared photographic shade guide. RESULTS: Total observations made during the study were 270. Cross table statistical analysis (Chi-square test) done using SPSS 20.0 showed statistically significant difference between conventional and digital photography (P = 0.049). Analysis between digital photography and polarizing filter photography did not reveal a significant association (P = 0.181). CONCLUSION: Digital photographic method was most accurate among the three shade selection methods. It can be used to obtain aesthetic results.