Irreversible Hydrocolloid Impression Material Research Articles

The Physical Properties of Vanillin-Incorporated Irreversible Hydrocolloid Impression Material

Irreversible hydrocolloid impression material is extensively used in dentistry to record and duplicate the details of tooth structure, surrounding tissue, and other intraoral structures. The materials allow dentists to work more easily and perform better diagnosis and treatment planning. When used, the material is exposed to oral microorganisms, some are pathogens, from the patient’s teeth, mucosa, blood, and saliva. These pathogens can be absorbed into the material and transmitted to dentists and other dental workers. Hydrocolloid impression material incorporated with vanillin has been shown to exhibit antimicrobial potential, however, its physical properties have not been performed. Therefore, this study aims to investigate the physical properties of a vanillin-incorporated irreversible hydrocolloid impression material on four different physical properties: working time, setting time, elastic recovery, and strain-in compression. The impression powder was mixed with varying concentrations of vanillin (0.1%, 0.5%, and 1.0% w/w) using the electric vacuum mixer. The impression material without vanillin was used as a control. All the tests were done following the ISO specification 21563: 2021 for dental materials with 15 specimens for each test. The result showed that at concentrations of 0%, 0.1%, and 0.5% w/w vanillin, no significant change in the four physical properties has been observed. However, the working time and setting time values of impression material with 1% vanillin were reduced significantly and did not meet the ISO standard. In conclusion, the incorporation of 0.1%, 0.5%, and 1% w/w vanillin into irreversible hydrocolloid impression material showed a significant reduction in setting time and working time. However, when considering the ISO standard specifications, the 0.1% and 0.5% w/w vanillin-added materials can still be used due to their acceptable values of all physical properties (setting time, working time, elastic recovery, and strain-in compression). These impression materials will be valuable for use in clinical settings to reduce the disinfection procedure and the risk of cross-contamination.

OPPORTUNITIES FOR TREATMENT WITH A TEMPORARY OBTURATOR MADE OF THERMOPLASTIC FOIL

Prosthetic treatment with a temporary obturator is an intermediate stage in the overall prosthetic rehabilitation of patients with maxillary resection. According to prevailing opinions, treatment with a temporary obturator should start around 2 weeks to 2-3 months after resection and to continue until the final completion of the healing processes in the defect. Due to the dynamic changes in the defect, this treatment stage is associated with many difficulties, requiring frequent correction of the obturator and up to 12-14 clinical visits on average. The aim of the research is to track the opportunity for fabrication of a temporary obturator of thermoplastic foil with vacuum forming apparatus and its efficiency for restoring speech and fluid intake in patients with maxillary resection. For the aim of the study we conducted a treatment of a 45-year-old patient operated a week ago for maxillary carcinoma. As a result, the left alveolar bone and a part of the hard palate with a diameter of 10 mm were resected, with teeth 13 to 23, 16 and 17 preserved. The defect was padded with gauze and an impression with an irreversible hydrocolloid impression material was taken. In the laboratory a grade 4 plaster working model was cast on which the borders of the palatal plate were outlined. For the frontal teeth, these were the cervical areas of the teeth, and for the distal - their equators. In the area of the defect and the missing teeth the border reached the transitional fold, and distally - the soft palate. The plate was made from foil of 1 mm diameter which was drawn onto the model with a vacuum forming apparatus and was cut along the indicated borders. The palatal plate - obturator successfully closed the comunication to the nasal cavity and restored the opportunity for fluid intake, which was the main problem for the patient. The use of a foil with a thickness of 1 mm provided stability and resistance of the construction. As a result of this, the necessary hermetic seal of the defect was achieved and the speech of the patient was normalised. The described treatment methodology with a temporary obturator allows the successful restoration of speech and fluid intake during the healing processes in the defect. The main advantages of the method are the fast and easy fabrication, the opportunity for multiple corrections and the short period of adaptation.

Comparison of Tearing strength and Dimensional Stability of Alginate Impression Material Mixed with Water and Chlorhexidine

Background:
 An irreversible hydrocolloid impression material combined with two different doses of chlorhexidine solution is tested for dimensional change and tearing strength. The aim of this study is to evaluate the impact of adding chlorhexidine with 2 different available concentrations on alginate impression material.
 Materials and Methods:
 According to the manufacturer's instructions, the irreversible hydrocolloid specimens is made and divided into 3groups (Group 1 is mixed with tap water as a control group, Group 2 is mixed with 0.12 chlorhexidine, and Group 3 is mixed with 0.2 chlorhexidine). Testing is done on the change in dimensions and the tearing strength.
 Results:
 Lesser dimensional change is observed at group two and is non-significant, and the group three is significantly more dimensionally stable when compared with group one, tearing strength of group one and two is nearly the same while the group three is more resistant to tear and the difference is significant
 Conclusion:
 The dimensional stability and tearing resistance of chlorhexidine self-disinfecting irreversible hydrocolloid impression material may vary greatly.

The Antimicrobial Potential of Vanillin-Incorporated Irreversible Hydrocolloid Impression Material

The hydrocolloid impression material is one of the most important materials extensively used in several procedures in the dental field. It is mainly applied for diagnostic and planning in the rehabilitation of oral, orthodontic, and maxillofacial prostheses due to its biocompatibility with the oral tissues, low toxicity, ease of use, and relatively low cost. When doing the impression, the material might be contaminated with blood, saliva, and biofilm from within the patient’s mouth. In these procedures, there are high chance that the microorganisms can be transmitted from patients to the casting materials and then to the dentists or to the dental lab technicians. Several types of disinfectants have been introduced for use to disinfect dental impressions. This study aims to investigate the antimicrobial potential of vanillin-incorporated irreversible hydrocolloid impression material on Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, and Candida albicans. The hydrocolloid impression material used in this study is Alginate, Kromopan class A type I, Lascod, Italy. Different concentrations of vanillin (0.1%, 0.5%, and 1% w/w) were added to the impression powder, and the impression samples were made by mixing the alginate powder with water and pouring them on sterile plastic plates. Staphylococcus aureus ATCC 5638, Klebsiella pneumoniae (clinical isolate), Escherichia coli ATCC 11775, and Candida albicans ATCC 10231 were prepared to 105 CFU/ml suspensions in sterile normal saline solution. A total of 100 μL of each microbial suspension was evenly spread onto the surface of the impression and left for 1 min. Then, a 2 x 2 cm2 sterile Whatman filter paper was placed on the impression sample surface to make an imprint and transferred to the Brain Heart Infusion (BHI) agar plate. The number of colonies growing on the BHI agar was counted after incubation at 37°C for 24-48 h. Impression material without vanillin was used as a control. It was found that adding vanillin to the materials could significantly inhibit all tested microorganisms, and the inhibitory efficiency ranged from 12% to 98%. K. pneumoniae showed the most resistance since the inhibitory effect started at 0.5% w/w vanillin and the maximum suppression was 84% at 1% w/w vanillin. On the other hand, S. aureus appeared to be the most sensitive species, as the suppressive response started at 0.1% w/w vanillin and the percentage of inhibition was as high as 98% at 1% w/w vanillin. In conclusion, we combined different concentrations of vanillin (0.1%, 0.5%, and 1% w/w) into the impression material and it showed a significant antimicrobial potential against all tested oral bacteria and yeasts (S. aureus, K. pneumoniae, E. coli, and C. albicans). The suppressive effects were dose-dependent and ranged from 12% to 98%. This did not only disinfect the impression material from the inside but also disinfected the impression from the time it was inserted into the patient’s mouth. Using this hydrocolloid impression material incorporated with vanillin could be beneficial to eliminate cross-infection for dental personnel. Nonetheless, further studies are necessary to investigate some physical properties of this impression material, such as setting time, tensile strength, elastic recovery, and detailed reproduction.

Silicone auricular prosthetics with adhesive retention: a case report

A-18-years-old male came to the Dental and Oral Hospital of Hasanuddin University with a complaint of losing his left ear due to a traffic accident several years ago and often feeling pain in his ear especially when blown by strong winds. The patient wants to make an auricular prosthesis so that his self-esteem returns to normal. The extraoral exa-mination showed convex profile, oval-shaped face, symmetrical eyes, nose and lips, submandibular lymph nodes ex-hibit without complaints. The right and left ears are not symmetrical. Manufacture of silicone auricular prosthesis with adhesive retention. Anatomical impressions of the patient's and his siblings' ears were performed as a guide for duplication of the patient's left ear using an irreversible hydrocolloid impression material. The wax pattern of the ear prosthesis that had been made on the die was paired with the patient to check the size accuracy and left and right symmetry. Then proceed with the process of acrylic packing and coloring. After the laboratory process was com-pleted, insertion is carried out. Signs of successful treatment: silicone ear prosthesis with adhesive retention has restored the patient appearance and self-esteem.

Evaluation of the Efficacy of Novel Self Disinfectant Solution in Irreversible Hydrocolloid Impression Material - An Experimental Study.

Irreversible hydrocolloid materials are widely used for both diagnostic and definitive impression procedures. Impressions can be disinfected by immersion or spraying in any compatible disinfectant. Disinfectants should not adversely affect the dimensional stability of the impression and physical properties of impression material and subsequent dental cast. The study aims to evaluate the efficacy of a hypochlorous disinfectant solution mixed with irreversible hydrocolloid on setting time, antibacterial efficacy, and dimensional stability. Three groups were made with one control group and three alginate impression was made for each participants in the maxillary arch with 24-hours intervals between one another using the same brand of commercially available chromatic alginate. The working and setting time were noted. Bacterial swabs were collected using a dry sterile cotton swab in the mid palatal region. Dental casts were made using type III gypsum. The working and setting time had significant differences whereas the dimension among the cast has no significant difference. Microbial growth analysis had distinct differences among the groups. The self disinfection method using a pioneer solution of hypochlorous HOCl (100 ppm) to mix the alginate impression material rather than the water with the same powder-liquid ratio prescribed by the manufacturer had the same dimensional stability with improved antimicrobial action.

A comparative evaluation of antimicrobial property of traditional and three alternative disinfectants on irreversible hydrocolloid impressions: An in vitro study.

The aim was to compare the efficacy of various herbal disinfectants on irreversible hydrocolloid impressions and to investigate the effectiveness of three herbal disinfectants and a chemical disinfectant against particular pathogens. In vitro -a comparative study. The following methodology was followed to achieve the objectives. Four maxillary impressions were made for each selected patient with irreversible hydrocolloid impression material. The predisinfection swabs were taken from impression sites of teeth 17, 13, 27, and 23 (FDI system of tooth numbering). The impressions were immersed in all four different disinfectants such as 2% glutaraldehyde, Aloe vera solution, 50% neem oil, and apple vinegar solution, then the postdisinfection swabs were taken from the same sites 17,13,27,23 and then cultured onto sheep blood agar and examined for growth, and colony forming units (CFUs) of Streptococcus viridans, Streptococcus mutans, Streptococcus sanguis, and Actinomyces viscosus. The comparative analysis was done for the predisinfection and postdisinfection values in each study group. Descriptive analysis, Kruskal Wallis test, Mann Whitney post hoc test, Wilcoxon signed rank test. The results revealed that the mean CFUs of S. viridans, S. mutans, S. sanguis, and A. viscosus during postdisinfection samples were statistically significant when compared to predisinfection samples. Multiple comparison of the mean CFUs of all 4 microorganisms in the control group and in 50% Neem oil group was significantly lesser compared to A. vera and Apple Vinegar group. CFUs of S. viridans, S. mutans, S. sanguis, and A. viscosus significantly decreased in the 50% neem oil group as well as the control group. As a result, 50% Neem oil was a viable option for disinfecting alginate impressions.

Digital Analysis of the Dimensional Change Of an Irreversible Hydrocolloid Impression Material (Alginate) with Varying Storage Times.

The aim of this study was to digitally measure the dimensional changes in an irreversible hydrocolloid impression material (alginate) resulting from varying storage times under optimal storage conditions. A single type V dental stone control cast was used to make 25 alginate impressions using perforated stock trays. The impressions were randomly assigned into five groups of five samples each (n=5 per group) with varying storage times: Group 1, poured at 15 minutes; Group 2, poured at one hour; Group 3, poured at 24 hours (one day); Group 4, poured at 72 hours (three days); Group 5, poured at 168 hours (seven days). All impressions were stored in sealed Ziploc® plastic bags with a wet paper towel (100% relative humidity) at room temperature and stored according to the assigned group storage times. All impressions were poured in type V dental stone according to the manufacturer's instructions. The casts were scanned with a digital 3D desktop scanner and saved as electronic stereolithography (.stl) files. Each .stl file of the scanned casts were superimposed on the .stl file of the control cast using Geomagic® Control X™ software. Three preselected fixed comparison measuring points (CMP) on each cast were compared to the control cast. Point one (CMP1) was on the midfacial surface of central incisor. Point two (CMP2) and point three (CMP3) were on the mesiobuccal proximal marginal ridge areas of third molars. The discrepancies between the files at each point were analysed with colour maps, and quantified (Table 1). The tolerance was set at ±10μm. CMP scores were analysed using one-way analysis of variance (ANOVA) and Kruskal-Wallis (K-W) non-parametric H tests. Average gap distances across groups ranged from 0.04mm (seven-day group) to 0.06mm (one hour and 24-hour groups). Colour maps indicated increased dimensional change with increased storage time up to one day. After three days, shrinkage up to 139μm was measured. ANOVA results for CMP1 (F[4,20] = 1.65, p = 0.020) and CMP3 (F[4,20] = 0.44, p = -0.78) were not statistically significant. Similarly, K-W results for CMP2 were not significant (χ2= 3.62, p = 0.46). Under optimal storage conditions, there were no significant dimensional changes in casts poured from alginate up to seven days.

Antifungal Activity of Magnesium Oxide and Zirconium Oxide Nanoparticles Incorporated into Alginate Impression Material. In Vitro Study

Aims: The aim of this study was to evaluate the antifungal effect of adding nanoparticles with different concentrations into irreversible hydrocolloid impression materials. Materials and Methods: This study evaluated the antifungal effect of MgO and ZrO2 nanoparticles by Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) and using the Agar-Well diffusion method after incorporation of different concentrations of nanoparticles into irreversible hydrocolloid impression material. Results: The results of this study showed that MIC and MFC of magnesium oxide nanoparticles were 0.2wt% and 0.3wt% respectively and for zirconium oxide nanoparticles were 5wt% and 10wt% respectively. Conclusions: The incorporation of MgO and ZrO2 into irreversible hydrocolloid impression materials acts as antifungal agents.

Utilization of brown algae (Sargassum Sp) as dental impression material

ABSTRACT
 Two-thirds of Indonesia's territory is mostly waters. The United Nations Convention on the Law of the Sea in 1982 stated that the area of ​​Indonesian waters is 5.8 million km2 and there are 27.2% of all flora and fauna species. Algae is one of the most abundant biological resources in Indonesian waters, which is about 8.6%. In Indonesian waters, there are about 28 species of brown algae from six genera including Dyctyota, Padine, Hormophysa, Sargassum, Turbinaria andHydroclathrus. Brown al-gae have a large alginate content in their cell walls, approximately 40% of their dry weight. The alginate contained in brown al-gae canbe used in industrial fields, such as the dental impression material industry. The main active ingredients in the manufac-ture of irreversible hydrocolloid impression materials are sodium alginate, potassium alginate, and triethanolamine alginate. Sodium alginate and potassium alginate can be extracted from brown algae species such as Sargassum sp.

CORRELATION OF THE DISTANCE BETWEEN PTERYGOMAXILLARY NOTCHES AND THE COMBINED WIDTH OF MAXILLARY ANTERIOR TEETH IN DENTATE SUBJECTS - AN OBSERVATIONAL ANALYTICAL STUDY

Purpose: The objective of this study was to find the correlation of the distance between pterygomaxillary notches and the combined width of maxillary anterior teeth.Material &Methods:One hundred and twenty-six maxillary dentulous impressions were made (18-50 years old) using metallic stock tray and irreversible hydrocolloid impression material, then poured in dental stone. The distance between Pterygomaxillary notches and the mesiodistal width of six maxillary anterior teeth were measured by digital vernier calliper on a dental stone cast. The mean of the measurements was statistically analysed using Pearsons correlation co-efficient. Results: The mean distance between pterygomaxillary notches was 39.5 ± 3.7mm and the mean of combined width of six maxillary anterior teeth was 45.5 ± 2.A moderately significant correlation was found for the distance between pterygomaxillary notches and the combined width of maxillary anterior teeth (p<0.01, r=0.335).Only 11.2 percent of the samples showed a correlation between the combined width of maxillary anterior teeth and the distance between the pterygomaxillary notches. Conclusions: The relation between the combined width of maxillary anterior teeth and distance between the pterygomaxillary notches was significant (p<0.01). The distance between pterygomaxillary notches can influence the size of maxillary anterior teeth along with other factors.It was concluded that for every 1mm increase in the distance between the pterygomaxillary notches, there will be a 0.18mm increase in the dimension for the combined width of maxillary anterior teeth.Distance between pterygomaxillary notches is a reliable method for the selection of maxillary anterior teeth. Clinical Relevance To Interdisciplinary Dentistry: 1. This can be used for teeth selection in patients with nasal, eye defects where inter-alar/ inter-pupillary width is not reliable. 2. This correlation can be applied to any restorative procedures involving rehabilitation of maxillary anterior teeth.

Effect of Temperature on the Dimensional Accuracy of Irreversible Hydrocolloid Material at Different Storage Time Intervals

Aims: In this competitive arena, dentists are inevitably searching for dimensionally more stable and accurate material to produce precise, effective prosthesis. Amongst many impression materials used on a day-to-day basis, irreversible hydrocolloid impression materials are most commonly utilized due to easy manipulation, hydrophilic nature, elastic recovery, accuracy and cost-effectiveness. The main objective of this study was to observe the effect of temperature and storage time on the accuracy of an irreversible hydrocolloid material.
 Study Design: Experimental and in-vitro study.
 Place and Duration of Study: Department of Prosthodontics and Research Medical Centre, Liaquat University of Medical and Health Sciences, Jamshoro, February 2019 to July 2019.
 Methodology: Total one hundred and five impressions cast models were made using irreversible hydrocolloid impression material (Hygedent) from ideal maxillary dentoform model. There were three temperatures (25°C,35°C and 45°C) and two storage timings (15 minutes and 25 minutes) along with one control group (immediate pouring). Measurements were taken utilizing digital Vernier Caliper. On each cast, two measurements were recorded in a linear manner including anteroposterior (AP) and Cross arch (CA).
 Results: Results revealed that there is a significant difference between anteroposterior dimensional changes of distance from Mesial surface of maxillary right central incisor to distal surface of maxillary right first molar and cross-arch dimensional changes of distance from distal surface of maxillary right first molar to distal surface of maxillary left first molar at different storage temperatures and time intervals. This indicates that the dimensions are increasing directly as storage time and temperature increases which might be because of shrinkage of material due to increase in time of pouring. Shrinkage causes material to pull it towards the tray and increase the dimensions.
 Conclusion: This study concluded that the best results could be obtained with immediate pouring at 25°C temperature as compared to other observed temperatures.

A Promising Potential of Brown Algae Sargassum polycystum as Irreversible Hydrocolloid Impression Material.

This study aimed to investigate the potential use of brown algae Sargassum polycystum as irreversible hydrocolloid (alginate) impression material. Potassium alginate extracted from Sargassum polycystum was prepared in three different compositions (14%, 15%, and 16%) and mixed with other standard components to form an alginate impression material. Prior to that, the purity of potassium alginate was quantified with Fourier Transform Infrared Spectroscopy (FTIR) analysis. As a control material, the alginate impression material from a commercially available product was used. All alginate impression materials were then applied to a die stone model. Dimensional accuracy was measured by calculating the mesiodistal width of incisors in the generated dental cast using a digital caliper 0.01 accuracy (five replications). In addition, to evaluate the dimensional stability, the impression results were poured at four different periods (immediately, 5 min, 10 min, and 15 min). An independent t-test was performed to compare the measurement results with p < 0.05 considered significant. Analytical results confirm that the impression material containing 15% potassium alginate gives the best dimensional accuracy similar to control (p > 0.05). Meanwhile, the optimal dimensional stability was produced in the impression material containing 16% potassium alginate. Our study suggested that brown algae Sargassum polycystum has a promising potential to be used as an alginate impression material in clinical application.

Assessment of Self Disinfecting Capacity and Dimensional Stability of Irreversible Hydrocolloid Impression Material Mixed With Different Concentrations of Chlorhexidine Solution-An Invitro Study

Introduction: Impression materials are used to record the anatomical topography of oral tissues. Irreversible hydrocolloid is an impression material routinely used in dentistry. However, it retains bacteria, 2 to 3 times higher than other impression material. Spraying and immersion technique has been employed for disinfection of irreversible hydrocolloid with varying degree of success. Thus the need of impression material that has self-disinfecting capacity seems to be very important to have infection control in dentistry. Materials and Methods: This invitro study was done in two parts. Assessment of self-disinfecting capacity of irreversible hydrocolloid impression material mixed with different concentrations of chlorhexidine solution and dimensional stability of irreversible hydrocolloid impression material mixed with different concentrations of chlorhexidine solution. For assessment of self-disinfecting capacity, irreversible hydrocolloid was mixed with various concentrations of chlorhexidine (0.05%, 0.1%, 0.2%) and distilled water. Total 64 culture plates were prepared, n=16 for each group of microorganisms (E. coli, S. aureus, Pseudomonas, Klebsiella). Inhibition zones were measured for each microorganism. For dimensional stability, the specimens were divided into four groups similar to specimen for self-disinfecting ability. Total 56 samples were prepared, n=14 for each group. Interpretation (IP), Mesiodistal (MD), Buccolingual (BL), Occlusogingival (OG) dimensions were measured by digital Vernier caliper. One-way analysis of variance was done for assessment of self-disinfecting capacity and for dimensional stability. Dunnett comparison test was performed to test the significance between test and control. P value was calculated under the predetermined level of significance (0.05). Results: Zones of inhibition were observed around test specimens (groups 0.05, 0.1, 0.2), but not around control specimen (Group d/w). There was a significant difference in the mean diameters of the inhibition zones between test groups and control which was statistically highly significant (p &lt; 0.001). In the test for dimensional stability, no significant differences were detected among groups for all the measured dimensions (p&gt; 0.05). Conclusion: Irreversible hydrocolloid impression material mixed with chlorhexidine exhibits varying degrees of self-disinfecting activity without influencing the dimensional stability of set material.

Comparative Evaluation of Antimicrobial Activity of Irreversible Hydrocolloid Impression Material Incorporated with Various Disinfectants – An In-vitro Study

Background: Blood and saliva can easily contaminate the dental impressions. It contains variety of bacteria, fungi, and viruses which causes cross infection to health personnel &amp; environment. Therefore, sterilizing the impression material is the best way to avoid disease transmission. Spraying and Immersion technique are conventional methods of disinfection of irreversible hydrocolloid impression material but in both of these techniques impression is disinfected only on the surface. Self-disinfecting impression are disinfected throughout the impression material. This study categorized various disinfectants into Chemical, Herbal &amp; Physical. Nanoparticles and herbal disinfectants are mixed with irreversible hydrocolloid impression material, which will suggest its antimicrobial activity.&#x0D; Aim &amp; Objectives: To evaluate and compare antimicrobial-activity of irreversible hydrocolloid impression materials incorporated with various disinfectants.&#x0D; Methodology: Commercially existing irreversible hydrocolloid impression materials will be used in the study. The disinfectants used will be chlorhexidine, silver nanoparticles and cinnamon. The selected disinfectants will be added into the irreversible hydrocolloid at the manipulation stage and their antimicrobial activity will be evaluated using the “Kirby Bauer Disk Diffusion Method” against the selected microorganisms.&#x0D; Expected Outcome: Differential Antimicrobial activity of Chlorhexidine, Silver Nanoparticle and Cinnamon when added to irreversible hydrocolloid for disinfection of impressions.&#x0D; Conclusion: Addition of various disinfectants in irreversible hydrocolloid may imbibe the antimicrobial activity within the impression materialand with the comparative investigations, more potent disinfectant can be applicable for clinical use as per findings of the present study.

Optimization of antimicrobial efficiency of silver nanoparticles against three oral microorganisms in irreversible hydrocolloid impressions.

Background and Objectives:Silver nanoparticles (Ag-NPs) are potent antimicrobial agents, which have recently been used in dentistry. The aim of the current study was to optimize antimicrobial activity of Ag-NPs used in preparing irreversible hydrocolloid impressions against three microorganisms of Escherichia coli, Streptococcus mutans and Candida albicans.Materials and Methods:After assessing antimicrobial activity of the compound using disk diffusion method, three parameters of concentration of Ag-NPs (250–1000 ppm), ratio of hydrocolloid impression material powder to water (0.30–0.50) and time of mixing (20.0–60.0 s), affecting antimicrobial activity of irreversible hydrocolloid impression materials against the three microorganisms, were optimized. This combined process was successfully modeled and optimized using Box-Behnken design with response surface methodology (RSM). Decreases in colony number of E. coli, S. mutans and C. albicans were proposed as responses.Results:Qualitative antimicrobial assessments respectively showed average zone of inhibition (ZOI) of 3.7 mm for E. coli, 3.5 mm for S. mutans and 4 mm for C. albicans. For all responses, when the mixing duration and powder-to-water ratio increased, the circumstances (mixing duration of 59.38 s, powder-to-water ratio of 0.4 and Ag-NP concentration of 992 response) increased. Results showed that in optimum ppm, the proportion of decreases in colony numbers was maximum (89.03% for E. coli, 87.08% for S. mutans and 74.54% for C. albicans). Regression analysis illustrated a good fit of the experimental data to the predicted model as high correlation coefficients validated that the predicted model was well fitted with data. Values of R2Adj with R2Pred were associated to the accuracy of this model in all responses.Conclusion:Disinfection efficiency dramatically increased with increasing of Ag-NP concentration, powder-to-water ratio and mixing time.

Evaluation of Effectiveness of Three New Gingival Retraction Systems: A Comparative Study

To analyze the clinical effectiveness of three new gingival retraction systems: knitted retraction cord, expanding polyvinyl siloxane, and aluminium chloride containing paste. Twenty patients were enrolled with age-group of more than 18 years and who required fixed prosthesis with minimum of two abutments. A preliminary impression of the arch was made with a stock metal tray and irreversible hydrocolloid impression material. Group WR-impression without retraction, Group A-impression after retraction with gingival retraction cord, Group B-impression after retraction with expanding polyvinyl siloxane, and Group C-impression after retraction with aluminium chloride containing paste. A total of four impressions were made for each abutment tooth. Each impression was given a label 1WR, 1A, 1B, 1C-20WR, 20A, 20B, 20C: where 1 denoted the sample number. Comparison of the stereomicroscopic images was done using image analysis software. Time required from start of placement of gingival displacement agents till completion was recorded in seconds with the help of a stop clock. The mean gingival retraction was found to be the highest for subjects of Group C followed by Group A, Group B, and Group WR. This difference was found to be statistically significant. Highly significant mean difference in time of placement was observed between Group A and Group B, between Group B and Group C, and between Group C and Group A. The aluminium chloride containing paste was found effective in almost all the variables considered. The choice of particular gingival retraction system/technique is dependent upon the clinical variables and on operator's preference.

The Pattern of Palatal Rugae in sub-population of Pakistani adults

Background: Despite the existence of the most reliable and authentic tools of personal identification such as fingerprints, dental, and DNA analysis, the palatal rugae are recommended as an adjuvant aid in forensic diagnosis. Palatal rugoscopy or palatoscopy aims to specify a person’s identity and gender discrimination. Aim: To determine the morphological pattern of palatal rugae considering gender. Settings and design: Cross-sectional study, calcorrugoscopy, chi-square test Material: This incorporated 360 subjects encompassing an equal ratio of the male and female genders. Undertaking the inclusion and exclusion criteria of the study, calcorrugoscopy technique was utilized in which maxillary casts were obtained through irreversible hydrocolloid impression material (Cavex cream alginate – fast set) and poured in type III dental stone. The assessed morphological parameters were shape and unification. Trobo’s classification and Thomas and Kotze’s criteria were used to assess shape and unification respectively to assess the qualitative aspect of palatal rugae. Descriptive analysis was generated in terms of frequencies, percentages, means, and standard deviations. Results: The most frequently occurred rugae pattern was sinuous followed by a line with divergent unification. Sexual dimorphism was not evident among the selected subjects regarding rugae shape and unification configuration.Moreover, the same trend regarding shape and unification was repeated on both sides of the palate, with no significant difference noted in number of palatal rugae undertaking both sides. Conclusions: Every individual possesses a unique rugae pattern irrespective of gender. Keywords: Cross- sectional, Adults, Gender dimorphism, Pakistan, Palatal rugae

Antimicrobial Efficacy of Irreversible Hydrocolloid Impression Impregnated with Silver Nanoparticles Compared to Surface Disinfected Impressions - An In vivo Study.

Background:Routine disinfection procedures have shown to cause incomplete disinfection and detrimental effects on dimensional properties of the impression. Hence, self-disinfecting impression materials impregnated with antimicrobial agents were developed.Purpose:The purpose is to evaluate the antimicrobial efficacy of silver nanoparticles (AgNPs) impregnated in irreversible hydrocolloid (IH) impression material in in vivo conditions.Materials and Methods:This study comprised of four groups-IH impressions disinfected by immersion in 2% glutaraldehyde, IH impregnated with AgNPs of sizes 80–100 nm and 20–30 nm, nondisinfected impressions as control. Five impressions were made for each group and a total of 20 impression samples were made. The antimicrobial action of each sample was assessed by counting the number of colony forming units and by disc diffusion method.Results:The results were obtained and the data were statistically analyzed by Kruskal–Wallis test and tabulated. The results revealed that AgNPs of size 80–100 nm when impregnated in irreversible impression material showed effective antimicrobial action.Conclusion:The anti-microbial action of 80–100 nm AgNP impregnated IH impressions is comparable to that of impressions disinfected by immersion in 2% glutaraldehyde for 10 min.

Compressive and tensile strength measurement of irreversible hydrocolloid impression material made of brown algae Padina sp

Compressive and tensile strength measurement of irreversible hydrocolloid impression material made of brown algae Padina sp