Heat-cured Polymethyl Methacrylate Research Articles

The Effect of Aging on Artificial Saliva at Different pH Values on the Color Stability of New Generation Denture Base Materials.

New-generation denture base materials are used successfully in denture fabrication; however, the effect of saliva pH change on the color stability of materials is unknown. The purpose of this in vitro study is to evaluate the color stability of new-generation denture base materials after immersion in artificial saliva with different pH values (3,7,14). Disc-shaped samples (Ø 10 mm x 2 mm) were prepared from three different denture base materials (1 pre-polymerized polymethylmethacrylate [PMMA], 1 graphene-reinforced PMMA, and heat-cure polymethyl methacrylate resin) (n=10). After polishing, color coordinates were measured using a PCE-CSM 5 colorimeter programmed in the CIE system (L* a* b*). The samples were kept in artificial saliva at different pH values and 37°C for 21 days. At the end of 21 days, color coordinates were measured again. The suitability of the measurements for a normal distribution was examined with the Kolmogro-Smirnov test. Whether color measurements obtained at different pH levels differed according to groups was examined with the Kruskal-Wallis test. The correlation between the CIEDE2000 and CIELab color difference formulas was examined by correlation analysis. The highest color difference occurred in heat-cure samples at pH 3 (p<0.001). The color difference at different pH values was least observed in pre-polymerized PMMA samples. Significant color differences occurred in the graphene-reinforced pre-polymerized PMMA group at pH 7 (p<0.001). It was observed that color differences occurred in all groups. Dentures made of new-generation CAD/CAM PMMA, which are less exposed to color differences, can be recommended for elderly patients with systemic diseases who are frequently exposed to pH changes in the oral cavity. Color differences on denture surfaces over time negatively affect aesthetics. Since pH changes cause changes on the prosthesis surface, it may be recommended for these patients to fabricate dentures from new-generation CAD/CAM PMMA resins, which are less deformable.

The Influence of Contemporary Denture Base Fabrication Methods on Residual Monomer Content, Flexural Strength and Microhardness.

(1) Background: Digital technologies are available for denture base fabrication, but there is a lack of scientific data on the mechanical and chemical properties of the materials produced in this way. Therefore, the aim of this study was to investigate the residual monomer content, flexural strength and microhardness of denture base materials as well as correlations between investigated parameters. (2) Methods: Seven denture base materials were used: one conventional heat cured polymethyl methacrylate, one polyamide, three subtractive manufactured materials and two additive manufactured materials. High-performance liquid chromatography was used to determine residual monomer content and the test was carried out in accordance with the specification ISO No. 20795-1:2013. Flexural strength was also determined according to the specification ISO No. 20795-1:2013. The Vickers method was used to investigate microhardness. A one-way ANOVA with a Bonferroni post-hoc test was used for the statistical analysis. The Pearson correlation test was used for the correlation analysis. (3) Results: There was a statistically significant difference between the values of residual monomer content of the different denture base materials (p < 0.05). Anaxdent pink blank showed the highest value of 3.2% mass fraction, while Polident pink CAD-CAM showed the lowest value of 0.05% mass fraction. The difference between the flexural strength values of the different denture base materials was statistically significant (p < 0.05), with values ranging from 62.57 megapascals (MPa) to 103.33 MPa. The difference between the microhardness values for the different denture base materials was statistically significant (p < 0.05), and the values obtained ranged from 10.61 to 22.86 Vickers hardness number (VHN). A correlation was found between some results for the material properties investigated (p < 0.05). (4) Conclusions: The selection of contemporary digital denture base manufacturing techniques may affect residual monomer content, flexural strength and microhardness but is not the only criterion for achieving favourable properties.

Antifungal Effect and Durability of Chitosan Oligosaccharide Coating on Heat-cured Polymethylmethacrylate Surface

This study aimed to investigate the antifungal effect against Candida albicans (ATCC® 10231) and the durability of chitosan oligosaccharide (COS) coated on heat-polymerized polymethylmethacrylate (PMMA). The various concentrations of COS solution, 0.5, 1 and 2-fold of minimum fungicidal concentration (0.5, 1 and 2 MFC) were prepared and applied to PMMA specimens treated with sandblasting (SB), application of 3-aminopropyltriethoxysilane (APS), and a combination of both procedures (SB&amp;APS). The toothbrush abrasion test was done to evaluate the remaining COS (n=10). The antifungal effect was determined through the colony count method (n=3). The number of fungal colonies was recorded at 16 and 48 hours. Data were analyzed using two-way and one-way ANOVA at the 95% confidence level. The result of the toothbrush abrasion test revealed that COS concentration and surface treatment affected coating durability. APS and SB&amp;APS groups showed a high percentage of COS and significantly differed from SB groups (P = 0.00). For the antifungal effect, coatings with 1 MFC and 2 MFC demonstrated no difference, but coating with 0.5 MFC differed from others (P = 0.00). At 16 and 48 hours, PMMA coated with 1 MFC and 2 MFC by APS and SB&amp;APS methods inhibited C.albicans. COS can be coated onto PMMA using APS and can inhibit C.albicans. With further development, this method could be applied to treat denture stomatitis alternatively to conventional antifungal drugs. Keywords: Candida albicans, Chitosan, Oligochitosan, Polymethylmethacrylate, Silanes

Comparative Assessment of Flexural Strength in Heat-cured Polymethyl Methacrylate Resin Reinforced with Silver Nanoparticles, Siwak, and Fluconazole: An In-vitro Study

Introduction: For crafting complete dentures, Polymethylmethacrylate (PMMA) has long been the material of choice. Various reinforcements are being used to enhance the properties of PMMA and minimise denture fracture. Aim: The present in-vitro study compared the flexural strength of PMMA resin samples reinforced with Silver Nanoparticles (Ag NP), siwak, and fluconazole. Materials and Methods: The present in-vitro experiment was conducted from July to August 2017 at the Prosthodontics Department of a Dental College with technical support from the Centre for Scientific Research and Development (CSRD), affiliated with People’s University in Bhopal, Madhya Pradesh, India. Flexural testing was conducted at the Central Institute of Plastic Engineering and Technology (CIPET), Bhopal. A total of 120 acrylic resin samples, each measuring 65 mm in length, 10 mm in width, and 2.5 mm in thickness, were fabricated in accordance with American Dental Association (ADA) Specification No. 12. These specimens were categorised into four distinct groups. The first group consisted of only PMMA resin (Group A), while the remaining three groups comprised PMMA resin enhanced with AgNP (Group B), Siwak (Group C), and Fluconazole (Group D), respectively, with each group containing 30 samples. Subsequently, these specimens underwent a flexural strength assessment through a 3-point flexural test. The statistical analysis to assess and compare the mean flexural strength of the samples was conducted. The present analysis was performed first by applying an Analysis of Variance (ANOVA) test, followed by pairwise comparisons with Tukey’s Post-hoc test. A p-value less than 0.05 was used to determine statistical significance. Results: The mean flexural strength (±Standard Deviation) in N/mm2 for PMMA; PMMA+AgNP; PMMA+Siwak and PMMA+ Fluconazole was 82.33±5.18; 80.55±5.67; 71.50±10.15; and 74.03±10.84, respectively. The mean flexural strengths of the PMMA and PMMA+AgNP groups were similar (p=0.842). However, the flexural strength of the Siwak+PMMA and Fluconazole+PMMA groups was significantly less than that of the other two groups. Conclusion: The flexural strength of PMMA is unaffected by the inclusion of AgNP at a concentration of 1%, and its incorporation would allow the benefit from its antibacterial qualities. It is not advised to add fluconazole or siwak because doing so reduces the flexural strength.

Altering Water Effect and Surface Properties of Heat Cured Poly Methyl Methacrylate by Adding Surface Treated Titanium Di Oxide Nano Particles

Titanium dioxide (TiO2) is extensively used part of our regular life. It can be observed in various commonly utilized goods &amp; customer imports for instance drugs, plastics, cosmetics, food and paper. Universally, the quantity of titanium oxide manufactured in 2009 was 4.68 million tons for that reason the tenacity of the revision is controlling the amount of change on the denture base physical features such as the heat treatment in denture processing (PMMA)through the implementation of modified outer surface titanium di oxide Nano particles. Its properties are comprised of water solubility, surface roughness, water sorption and surface hardness. The contr olled TiO2 powder added to heat cured acrylic material according to the main weight of PMMA in concentration of 3% , 5% and 7%, and then it's mixed regularly by engine of probe ultra-sonication. Titanium oxide Nano fillers were m erged in denture based material with the help of more free radical polymerization in bulk. The nanoparticles were surface treated by a layer of trime thoxysilypropylmethacrylate (TMSPM). 120 specimens were created and separated into 3 sample sets affording to the examination (each sample sets consist of 40 samples) and each sample sets were sectioned in four subsets according to the TiO2 added ratio and ultimately containing 10 samples in each subset. The tests which conducted were indentation hardness (shore D), surface roughness properties as well as water sorption and solubility. For each test four of the sub groups (one control led and three with added Nano TiO2). Important to mention that extremely elevation in surface hardness score and roughness were detected at the ratio of 3%, 5%and7%. Thus escalation of added TiO2 nan-fillers considerably reduced the water solubility and sorption. The accumulation of the powder of TiO2 nanoparticles which have been surface treated to the PMMA acrylic resin thus changing the PMMA properties for example surface rigidity and surface coarseness. In which it’s increased in direct proportional relation with the raise of TiO2 concentration; at the same time addition of surface treated TiO2 Nano particles decrease water sorpt ion and solubility of (PMMA) also in direct proportional relation with the raise of TiO2 concentration.

Effect of Knitting Pattern of PP Mesh on the Flexural Properties of Heat-cured PMMA Denture Base Resin

Heat-cured polymethyl methacrylate is (PMMA) is the most common denture base material and some mechanical properties such as flexural strength and impact resistance etc. may lead to fail, besides its excellent properties. Polypropylene (PP) hernia mesh is a commercially available medical textile used in surgical repair of different types of hernia. It was aimed to investigate the effect of two different knitting patterns of PP meshes on the flexural properties of the PMMA denture base resin when they are used as reinforcement and compare with glass fiber mesh reinforced and no mesh used resins. Knitting patterns of the PP mesh structures were hexagonal honeycomb pattern and square pattern and these were used as single or double layer as reinforcement. 6 groups were established in the study: control group with no mesh and 5 reinforced groups with meshes (glass fiber mesh, single layer honeycomb patterned PP mesh, double layer honeycomb patterned PP mesh, single layer square patterned PP mesh, double layer square patterned PP mesh). A total of 60 samples with the dimensions of 65x10x3 mm, n=10 in each group were fabricated. The flexural strength, maximum deformation, and flexural modulus were determined by three-point bending test. Fracture surfaces were evaluated by scanning electron microscopy. The obtained data were statistically analyzed by two-way ANOVA test with Bonferroni corrections. The single layer square patterned PP mesh group exhibited the highest (76.67 ± 7.64 MPa), and the control group showed the lowest (63.49 ± 7.18 MPa) flexural strength values. The single layer glass fiber mesh group showed the highest (7.13 ± 0.55 mm) and the control group showed the lowest (4.72 ± 0.81 mm) maximum deformation values. The single layer glass fiber mesh group exhibited the highest (2131.87 ± 205.76 MPa), and the control group exhibited the lowest (1582.26 ± 98.63 MPa) flexural modulus values. Significant increase in flexural strength was observed in all polypropylene mesh-reinforced groups compared to the control group except double layer honeycomb patterned PP mesh group (p &amp;lt; 0.05). Using PP fiber mesh for reinforcement provide a very favorable aesthetic view and PP fiber mesh is concluded to be a promising material for reinforcement of heat-cured PMMA denture base resins.

Effect of ultraviolet irradiation treatment on shear bond strength between polymethyl methacrylate and cobalt-chromium-molybdenum alloy.

We aimed to elucidate the effects of ultraviolet (UV) irradiation on the shear bond strength (SBS) between heat-cured polymethyl methacrylate (PMMA) and a Co-Cr-Mo alloy. Disk-shaped Co-Cr-Mo alloy prepared by casting were subjected to different UV treatment times (0, 15, and 30 min). To determine the effect of UV treatment on surface properties of the alloy, surface roughness, wettability, and chemical compositions were analyzed. To evaluate the SBS, cylindrical PMMA was bonded to the UV-treated alloy, and subsequently subjected to the SBS test after 24 h of storage at room temperature or following 10,000 thermal cycles (n=10/group). After the UV treatment, the surface roughness remained unchanged, but oxidation resulted in the surface exhibiting greater hydrophilic characteristics. The UV-treated group showed significantly higher SBS values than those of the non-treated group (p<0.001). These results suggested that UV treatment-mediated oxidation improved the bond strength between PMMA and Co-Cr-Mo alloy.

An In Vitro Study Comparing the Impact and Flexural Strength of Leucitone 199 Denture Base Resin and Conventional Denture Base Resin Enhanced With Glass Fibre Mesh and Polyethylene Fibre Mesh.

Purpose The purpose of this in vitro study was to compare and evaluate the impact and flexural strength of conventional denture base resin reinforced with glass fiber mesh and polyethylene fiber mesh with Leucitone 199 denture base resin (Dentsply Sirona, Charlotte, USA). Leucitone is an expensive denture base material. To come up with a cheaper solution for reinforced denture base resin with superior impactand flexural strength was the goal of this study Material and methods The specimens (maxillary denture bases) were fabricated using a standard polyvinylsiloxane mold with conventional heat-cured polymethyl methacrylate resin (ISO 1567:1999). The specimens were divided into three groups (n = 10). Group I specimens, or the control group, were pre-reinforced Leucitone 199. Group II and Group IIIspecimens were reinforced with 3% by weight of glass fibers and polyethylene fibers in weave form, respectively. All the specimens were immersed in water for 1 week before testing. The impact strength was measured with a falling weight impact testing machine. One-way analysis of variance and Tukey's post hoc test were used for statistical analysis. The flexural strength was measured with the three-point bending test in a universal testing machine. Results The highest impact strength values were exhibited by the Leucitone 199 group, followed by the polyethylene fiber mesh group, followed by the glass fibers mesh group. The highest flexural strength was seen in the Leucitone 199 group, followed by the glass fiber mesh group. The least flexural strength was seen in the polyethylene fiber mesh-reinforced group. Conclusion Reinforcement of maxillary complete dentures showed a significant increase in impact strength and flexural strength, but not in comparison to pre-reinforced Leucitone 199 dentures. By using pre-impregnated glass and polyethylene fibers in woven form (prepregs), the impact strength of the denture bases can be increased effectively.

Flexural Properties of Heat-Polymerized PMMA Denture Base Resins Reinforced with Fibers with Different Characteristics.

Polymethylmethacrylate (PMMA) has been the most-widely used denture base material in prosthetic dentistry for the last 80 years. It is still one of the best alternatives when new methods are inapplicable. Due to the lack of some physical inadequacies occurring during cyclic use and accidental situations, various reinforcement strategies such as using nanoparticles, wires, fibers, and meshes have been investigated and reported. In this study, it was aimed to conduct a comparative investigation of the effect of fiber additives with different characteristics on the flexural properties of heat-cured PMMA denture base resins. Glass fibers (GFs), polypropylene fibers (PPFs), and carbon fibers (CFs) having 3, 6, and 12 mm lengths and 0.25, 0.50, and 1.0% concentrations (v/v) were used for the reinforcement of PMMA denture base resins. The flexural properties (flexural strength, flexural modulus, and maximum deformation) were determined using a three-point bending test, and three-way ANOVA analyses with Bonferroni corrections were performed on the test results. The morphologies of the fracture surfaces were analyzed using scanning electron microscopy. All three fibers exhibited reinforcement in the flexural strength (p < 0.001) and flexural modulus (p < 0.001) regardless of their length and concentration. The group with 1.0% 12 mm CF-reinforced PMMA exhibited the greatest flexural strength (94.8 ± 8.8 MPa), and that with 1.0% 3 mm GFs displayed the lowest flexural strength (66.9 ± 10.4 MPa) among the fiber-reinforced groups. The greatest value of the flexural modulus was displayed by the 1.0% 3 mm CF-reinforced resin (3288.3 ± 402.1 MPa). Although the CF-reinforced groups exhibited better flexural properties, CFs are not favorable for use as reinforcement in practice due to the dark gray discoloration of the denture base resin. It was concluded that PPF is a promising material for the reinforcement of heat-cured PMMA denture base resins.

A Study on Speech Analysis in Acquired Maxillary Defect Patients Treated with Maxillary Obturator.

The aim of the present study was to assess the speech analysis in acquired maxillary defect patients treated with maxillary obturator. Total of 16 patients were considered in the study. The age group of these patients ranged from 40 to 75 years with a mean age of 59.5 years, irrespective of their gender. The surgical obturator was fabricated using self-cure acrylic. The surgical obturator was delivered immediately after surgery. After a healing period of about 2 weeks, the surgical obturator was replaced by an interim prosthesis. This was processed with the help of heat-cure polymethylmethacrylate. The total number of patients was divided into two groups, namely, (A) Definitive obturator group and (B) Interim obturator group. The speech intelligibility (SI), was analyzed. The mean scores for SI before prosthesis in definitive and interim groups were 19.13 ± 3.22 and 19.87 ± 1.72, respectively. This was increased after prosthesis insertion to 24.38 ± 1.30 and 22.37 ± 1.18, which further increased after adaptation period of 2 months to 28.75 ± 1.28 and 24.62 ± 1.59 in two groups. The present study concluded that speech was severely affected by maxillary resection and that rehabilitation with maxillary obturator was successful in restoring these aspects of speech.

Effect of titanium oxide nanoparticles on polymerization reaction of heat and microwave cured polymethylmethacrylate: in vitro study

BackgroundTitanium Oxide Nanoparticles (TiO2NPs) have been introduced to polymethyl methacrylate (PMMA) denture base to enhance its mechanical, physical, and biological performance.ObjectivesThis research aimed to assess the effect of adding TiO2NPs on the degree of polymerization and morphological characterization of heat and microwave cured PMMA.Materials and methodsFabrication of PMMA specimens which were categorized according to the curing technique into heat cured (group I) and microwave cured (group II). Each group was subdivided into two subgroups A and B according to the addition of TiO2NPs. A total number of 24 specimens were fabricated. Each subgroup contains 6 specimens. The specimens were characterized by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDX). The polymerization reaction of specimens was assessed by Attenuated Total Reflection Fourier-Transform Infra-Red Spectroscopy (ATR-FTIR). Results were statistically analyzed using an independent T-test and one-way ANOVA. The significance level was set at p < 0.05.ResultsSEM/EDX revealed that TiO2 NPs appeared as bright areas in the matrix of both groups. The matrix showed organic impurities and minute internal cracks, but group IIB (microwave-cured PMMA with TiO2NPs) showed higher organic impurities than heat-cured PMMA. The FTIR revealed that the addition of 3% by weight TiO2NPs decreased the degree of polymerization of both heat and microwave-cured PMMA but the decrease was insignificant (p > 0.05).ConclusionsIncorporation of 3% by weight TiO2NPs does not significantly affect the degree of polymerization of both heat and microwave-cured PMMA. Hence, denture materials can benefit from the advantages of the TiO2NPs without any alterations to their structures.Graphical abstract

A Comparative Evaluation of Flexural and Impact Strength of Polymethyl Methacrylate (PMMA) Reinforced With Graphene and Multi-Walled Carbon Nanotubes: An In Vitro Study.

Background and objective Low flexuralstrength (FS) and impact strength (IS) are major drawbacksin removable prostheses made from polymethyl methacrylate (PMMA). Attempts to enhance the strength and longevity of theseprostheses have been of keen interest among researchers. Nanofillers are new and advanced reinforcements that can chemically modify PMMA. Graphene and multi-walled carbon nanotubes (MWCNTs) were used in this study to evaluate FS and IS when added to polymer and monomer individually. Method Four groups were created based on the addition of nanofillers: no nanofillers - control; 0.5% by weight of graphene; 0.5% by weight of MWCNT; and 0.25% by weight of both. These groups were further subdivided into two according to the nanofiller being added to polymer and monomer each. The samples were then subjected to a 3-point bending test to assess FS, and an Izod impact tester was used to test IS. Results Decreased FS and FS were seen in all groups with the addition of nanofillers in the polymer (p<0.001). With the addition of nanofillers in monomer, increased FS and IS were seen in groups with MWCNTs whereas a decrease was seen with the addition of graphene (p<0.001). Conclusion Nanofillers should be added to the monomer of heat-cure PMMA instead of polymer; 0.5% by weight of MWCNT has shown the highest FS and IS when added to the monomer.

Evaluation and Comparison of Mechanical Properties of Heat Polymerized Acrylic Resin After Reinforcement of Different Fibers in Different Patterns: An In Vitro Study.

Most denture fractures occur within the mouth due to resin flexural fatigue. For example, the deep labial notch at the high labial frenum causes denture breakage, as can deep scratches and generated processing stresses. The rising cost of annual prosthetic repairs is evidence that the problem of total denture fracture has not been solved. The purpose of this investigation was to evaluate the relative improvement in flexural strength between heat-cured polymethyl methacrylate (PMMA) resin reinforced with glass fibers (GF) and basalt fibers (BF) of varied orientations. A total of 150 heat-cured acrylic resin specimens of 65x10x3 mm dimension were prepared, 30 of which were left unreinforced (Group A), 30 of which were reinforced with GF in transverse pattern (Group B), 30 of which were reinforced with GF in meshwork pattern (Group C), 30 of which were reinforced with BF in transverse pattern (Group D), and 30 of which were reinforced with BF in meshwork pattern (Group E).All of the samples were put through flexural strength testing on the universal testing machine. One-way ANOVA and the Tukey-Kramer various correlation test (= 0.05) were used in SPSS for Windows to look at the facts. The mean flexural strength for Group A was 46.26±2.26 MPa, 64.98±1.53 MPa for Group B, 76.45±2.67 MPa for Group C, 54.22±2.24 MPa for Group D, and 59.02±2.38 MPa for Group E. Flexural strength was impacted by both the kind of BF and GF reinforcement (F = 768.316, P = 0.001). Within the limitation of the current research, BF reinforcement outperforms GF reinforcement and unreinforced heat-cured acrylic resin in terms of flexural strength.

Evaluation of polyamide (NYLON) versus polymethyl methacrylate (PMMA) denture base materials regarding water solubility: in vitro research

BackgroundSeveral denture base materials have evolved over the years. Beginning with metal and ending up with various types of acrylic materials in order to have a biocompatible, antimicrobial denture base. A flexible acrylic resin, such as Polyamides, has been introduced to address the drawbacks of heat-cured PMMA resin. This study was conducted to examine the water solubility and water sorption of flexible thermoplastic polyamides (Valplast) and two types of conventional heat-cured acrylic resin (PMMA) (Acrostone, Vertex).MethodsSpecimens of thermoplastic polyamides and two types of conventional PMMA (Acrostone, Vertex) resin were manufactured and used in the current investigation in accordance with manufacturer instructions. A total of 45 specimens were milled into discs with a diameter of 50.0 mm diameter, 5.0 mm thick. To ascertain conformity with ADA Standard No. 12, water solubility and water sorption were measured.ResultsAll items complied with ADA regulations for water solubility and sorption. Flexible thermoplastic polyamide displayed less water solubility, and water sorption than heat-cured PMMA. Acrostone showed the higher water solubility, sorption followed by Vertex heat cure acrylic resin both heat cured showed significant higher water solubility than polyamides Valplast).ConclusionsWithin the limitations of this in vitro experiment, heat cure PMMA resin demonstrated significantly greater water solubility and water sorption when compared to thermoplastic polyamides.

Complications of Different Types of Cranioplasty and Identification of Risk Factors Associated with Cranioplasty at a Tertiary Care Centre: A Prospective Observational Study

Abstract Objective Decompressive craniectomy (DC) is an urgent procedure which is done to decrease intracranial pressure. A study of the complications would suggest measures to improve the care. This study was focused on analyzing the complications after cranioplasty (CP) and to identify risk factors that may be associated with the failure of the procedure. Method: This study was conducted over 41 months at level-1 trauma center and medical college. It included patients undergoing CP for a defect arising out of previous DC or inability to replace the bone flap (Glasgow Coma Scale &gt; 13, size &gt; 5 cm, without surgical site infection). All patients underwent CT imaging before and after the procedure. The CP technique largely depended on the patients, based on the cost of prosthesis and availability. Result: Hundred patients were included in the study. Postoperatively, total 22 patients suffered complications of which few had more than one complication. Titanium implant appeared to be a better implant, with no complication (p &lt; 0.05). Complication was common in younger age group, chemically cured PMMA (polymethyl methacrylate) and ethylene oxide) sterilized bone flap). Complications were higher among patients with multiple comorbidity and stroke patients. Conclusion: Titanium flap had no complication and in case of autologous abdominal subcutaneous flap, apart from bone flap absorption, patients had no major complication. Therefore, both implants are preferred implants for CP. Heat-cured PMMA can be used in case of nonavailability of a better option, as it is economical feasible and can be molded at any dental lab.

Effect of Incorporation of Boron Nitride Nanoparticles on Impact Strength and Surface Roughness of Heat Cure Poly Methyl Methacrylate Resin: An In Vitro Study

Background: The objective of this research was to explore how the addition of boron nitride (BN) nanoparticles in the concentrations of 1% and 1.5% w/w affect the impact strength and surface roughness of heat-cured poly methyl methacrylate resin (PMMA). Methods: Sixty specimens were made from heat-cured acrylic resin and then divided into control, 1%, and 1.5% w/w BN groups. The impact strength and surface roughness were investigated. One-way ANOVA and Tukey’s post hoc test were used for data analysis. Results: Statistically significant difference is found among the three study groups regarding impact strength (P = 0.011) and surface roughness test (P < 0.001). The post hoc test showed significant differences for all multiple comparisons for the surface roughness test (P < 0.001). Yet, multiple comparisons for the impact strength test revealed only a significant difference between the 1.5% BN and control groups (P = 0.005). Conclusion: The addition of boron BN into PMMA improves impact strength with 1.5% concentration; while adversely increase the surface roughness.

Anti-fungal efficacy of Miswak Extract (Salvadora Persica) and commercial cleaner against Candida albicans on heat cured polymethylmethacrylate denture base.

The aim of the study was to compare the antifungal efficacy between commercial cleaner (Corega) and Miswak extract (Salvadora persica) against Candida albicans on heat cured Polymethyl methacrylate (PMMA) acrylic denture base resin. Forty-eight samples of heat cured PMMA acrylic denture base resin were fabircated in the study. The sterile acrylic resin specimens were immersed in standardized cell suspension of Candida albicans and incubated for 60 min at 370°C for cell adhesion and 2 h at 370°C for biofilm formation. After 24 h biofilm was evaluated by cell viability (CFUs) on SDA and cell counting of Candida albicans under light microscope at 400× magnification. The fungicidal effect of commercial cleaner and Miswak extract on Candida albicans biofilm was then evaluated by colony-forming units on SDA and cell counting under light microscope at 400× magnification. Screening test agar disk-diffusion assay showed mean inhibitory zone of 3 mm for commercial cleaner as compared to Miswak extract, which showed mean inhibitory zone of 2 and 1 mm for different concentrations. Broth microdilution method showed 31 mg/ml MIC and 62.5 mg/ml Minimal Fungicidal Concentration (MFC) values for commercial cleaner as compared to Miswak extract that showed 125 mg/ml MIC and 250 mg/ml MFC values against Candida albicans. A significant difference (p < 0.05) was observed between pre and post treatment of both commercial cleaner and Miswak extract, for CFUs and cell count for Candida albicans. Commercial denture cleaner (Corega) showed better antifungal (C albicans) activity than Miswak extract (Salvadora persica) on heat cured PMMA acrylic denture base resin.

Comparative evaluation of surface roughness of herbal denture cleansing tablet containing essential oils of tulsi and lemongrass, 0.12% chlorhexidine digluconate, and commercially available denture cleansing tablet on heat cure polymethyl methacrylate denture base resin: An in vitro study

Comparative evaluation of surface roughness of herbal denture cleansing tablet containing essential oils of tulsi and lemongrass, 0.12% chlorhexidine digluconate, and commercially available denture cleansing tablet on heat cure polymethyl methacrylate denture base resin: An in vitro study

EFFECT OF IMMERSION AND INCORPORATION OF POLYVINYL CHLORIDE ON THE FLEXURE STRENGTH AND MICRO HARDNESS OF POLY METHYLACRYLATE DENTURE BASE RESIN

OBJECTIVE: To find the effect of artificial saliva, water and different percentages of polyvinyl chloride (PVC) on the flexural strength and microhardness of heat cure polymethylmethacrylate (HC-PMMA) denture base resin. METHODS: An in-vitro study conducted, from April-December, 2020, at the MRL University of Peshawar and Interdisciplinary Research Centre in Biomedical Materials (COMSATS) Lahore. Total of 100 specimens for five groups (n=20) denoted by A, B, C, D and E containing 0%, 5%, 10%, 15% and 20% PVC in HC-PMMA respectively were fabricated to test flexural strength. Each group was divided into two subgroups depending on immersion medium containing ten specimens each. Three-point bending test was used to determine flexural strength. Microhardness was determined using thirty (n=30) specimens through Vickers hardness tester. Statistical analysis was performed by using one way ANOVA and post hoc Tukey test. P-value &lt;0.05 was considered as significant. RESULTS: After immersion in water, one way ANOVA showed significant effect on flexural strength and Post-hoc Tukey’s test showed significant difference between group C and E (p&lt;0.001) and, D and E (p&lt; 0.001). Microhardness of A was significantly different from E after immersion in water (p&lt;.05). Similarly, after immersion in artificial saliva, one way ANOVA showed statistically significant effect on microhardness (p&lt; 0 .01) and Post-hoc Tukey’s test showed significant difference between group C and E (p&lt;0.01) and, A and C (p&lt;0.01). CONCLUSION: Flexural strength of HC-PMMA impregnated with 20% PVC increased after immersion in water, similarly, HC-PMMA containing 10% PVC shows increased microhardness after immersion in artificial saliva.

EFFECT OF GINGER EXTRACT (ZINGIBER OFCINALE ROSC.) ON CANDIDA ALBICANS ON HEAT CURED ACRYLIC RESIN PLATE

Background: Denture bases that are often used in dentistry are heat cured polymethyl methacrylate acrylic resin or heat polymerized acrylic resin. Acrylic resin has a weakness, namely the surface of the acrylic resin that can trigger the growth of bacteria and Candida albicans. Candida albicans has an important role in the occurrence of denture stomatitis. Epidemiological studies show the prevalence of denture stomatitis is quite high, ranging from 30%-50% in denture users. Innovation is needed to inhibit the growth of Candida albicans on acrylic resin, one of which is the use of ginger extract. Ginger can be antifungal because of the content of phenols and essential oils.To determine the effect of ginger extract (Zingiber ofcinale Rosc.) on Candida albicans on heat cured acrylic resin. Methods: This research design was a post test only control group design with a total sample of 24 samples. There was 3 treatment groups and 1 control group. Statistical test used One-way ANOVA Welch with post hoc Games-Howell test. Results: The results showed that there was a significant effect of 25% and 50% ginger extract on Candida albicans on heat cured acrylic resin. The Shapiro-Wilk test got normal results and the homogeneity test got inhomogeneous results. The analytic test conducted used One-way ANOVA Welch with post hoc Games-Howell and the result showed a significant differences in the 4 test groups Conclusion: There was a significant effect of 25% and 50% ginger extract in inhibiting Candida albicans on heat cured acrylic resin with an average fungal count of 2 and 1.