Evaluating the antifungal effectiveness, leaching characteristics, flexural strength, and impact strength of polymethyl methacrylate added with small-scale silver nanoparticles - An in vitro study.

AIM: (1) To assess the release of stable silver nanoparticles (AgNPs) of small scale dimension added to heat polymerized polymethyl methacrylate (PMMA) in 6 months. (2) Assessing the influence of incorporating minimal concentrations of stable AgNPs with nanoscale dimensions into heat polymerized PMMA over a 6 month period on its antifungal efficacy (AF), flexural strength (FS), and impact strength (IS). SETTINGS AND DESIGN: Incorporating nanoparticles with a very small scale may have minimal impact on mechanical properties due to their diminutive size. However, the influence of these small scaled nanoparticles on antimicrobial efficacy and potential escalation in toxicity to host cells through leaching remains unexplored. AgNPs were prepared using an Ultrasonic Probe sonicator and the addition of ammonia to obtain stabilized AgNPs (< 0.01 nm) of small scale dimension. The characterization of these AgNPs involved ultraviolet visible spectroscopy, X ray diffraction, Zetasizer, and transmission electron microscopy with energy dispersive spectroscopy (TEM). MATERIALS AND METHODS: The prepared AgNPs were then added in various percentages by weight (0%-0.5%) to fabricate 252 modified PMMA samples of sizes 10 mm × 3 mm (AF, n = 108), 65 mm × 10 mm × 3 mm (FS, n = 72), and 65 mm × 10 mm × 2.5 mm (IS, n = 72) as per ADA specification no. 12. These samples underwent testing for leaching out of AgNPs and efficacy against Candida albicans for 6 months. The effect on FS and IS was evaluated using the three point bending test and Charpy's Impact Tester, respectively. STATISTICAL ANALYSIS USED: Intergroup comparison of CFU between various concentrations of AgNP was done using the Kruskal-Wallis ANOVA test succeeded by Mann-Whitney test for pair wise comparisons. Difference in CFU of various concentrations over 6 months was seen using one way ANOVA test. Intergroup comparison of FS and IS was performed using a one way ANOVA test, followed by a post hoc Tukey's test for pair wise comparisons. RESULTS: Repeated tests showed no leaching out of AgNPs from the denture base resin into the storage medium. All concentrations of AgNPs incorporated in resin showed inhibition of Candida growth. Intergroup comparison of FS and IS revealed highly statistically significant differences (F = 15.076, P < 0.01 and F = 28.266, P < 0.01) between the groups showing a reduction in strength. CONCLUSION: The AgNPs of small scale dimension incorporated into the denture base resin imparted a strong antifungal effectiveness against C. albicans, which did not decline during the study period and did not cause any release of nanoparticles. 0.5% showed the best antifungal efficacy. This may prove to be a viable and highly effective treatment for the prevention of Candida associated denture stomatitis. However, the inclusion of these particles resulted in a decrease in both FS and IS, and this reduction was directly proportional to the percentage of added AgNPs, with 0.5% demonstrating the least IS and FS.

Reference values of Orthopantomographic indices for early detection of low bone mineral density in Indian population.

Purpose: Orthopantomographic (OPG) indices are considered tools for early screening for low Bone Mineral Density and Osteoporosis. This tool is being used in the western population, and they have developed their reference values for all the OPG indices. The current study aimed to check the validity of the reference values for OPG indices in the Indian population. Material and methods: A cross-sectional study was conducted on 325 participants, and they were recruited in two sets. Dataset one of 130 aged 20-30 years and dataset two of 195 participants aged 40-60 years. OPG was performed, and indices such as Mental Index (MI), Panoramic Mandibular Index (PMI), Gonial Index (GI) and Antegonial Index (AI) were measured. Values obtained in our study were compared with the established OPG indices for the Indian and Western populations. Results: The mean age of participants in dataset one to develop references was 23.5 ± 2.5 years. Females had a significantly lower MI, PMI, and AI than males (p < 0.05). MI was significantly higher in validation dataset one males than females (p < 0.05). A good agreement was found in MI and PMI of the two references (p < 0.05). Conclusions: The reference values derived from this study for MI, PMI, GI and AI are 3.50,0.27,1.10, 2.50, respectively. Compared with previous studies in Indian and western populations, these references were significantly lower.

Evaluation of Sagittal Inclination of Occlusal Plane and Horizontal Condylar Guidance Using Various Anterior Reference Points on Arcon and Nonarcon Articulators.

Aim: The aim of the study was to determine the effect of different anterior reference points during facebow transfer, on sagittal inclination of occlusal plane (SIOP) and horizontal condylar guidance (HCG) values obtained on arcon and nonarcon articulators. Materials and Methods: Facebow records of 25 participants were made and transferred to Hanau Wide-Vue (WV) and Hanau H2 (H2) articulators using conventional indirect transfer (CIT), superior annular groove (SAG), and inferior annular groove (IAG) as anterior reference points. Maxillary casts were mounted on each articulator followed by mandibular mountings. Protrusive interocclusal record was used to determine HCG, and SIOP was measured as an angle between the occlusal plane of mounted maxillary cast and upper member of the articulator. Both, HCG and SIOP were measured on a digital lateral cephalogram and the values obtained were compared with previously determined values from both the articulators. Intergroup comparison was done by analysis of variance and pair-wise comparison by Tukey post hoc test. Results: Values of SIOP significantly (P = 0.00) changed on both the articulators when CIT, SAG, and IAG were the anterior reference points. The ratio of SIOP and HCG on both articulators was comparable to that of the cephalogram for CIT, IAG, but it was substantially low for SAG. Conclusions: The variation of anterior reference point changes the value of SIOP recorded on Hanau WV and H2 articulators; however, it had no effect on HCG values recorded on both the articulators. The angle between SIOP and HCG changed with variations in superior-inferior position of the mountings on both articulators.

Reconstruction of a Craniofacial Defect Using Rapid Prototyping and an Autograft - A Case Report.

Rationale: Achieving predictable aesthetic results of large craniofacial defects has always been difficult, and it requires a multidisciplinary approach. Patient Concern: The chief concern of the patient was poor aesthetics due to a congenital craniofacial defect. Diagnosis: The patient was a known case of plexiform neurofibromatosis and had a congenital temporo-orbital bone defect of unknown origin. Treatment: The reconstruction of the defect was done using rapid prototyping (RPT) and iliac crest graft. Three-dimensional computed tomography imaging and RPT were used to obtain a customized titanium prosthesis to rehabilitate the temporal defect and the defect lateral to the orbit was reconstructed using an iliac crest graft. Outcome: Postoperative results were satisfactory and predictable. The positive change in appearance has improved the psychological well-being of the patient. Take-away Lessons: A multidisciplinary approach, use of advanced and improved technology helps in better treatment planning and achieving desired aesthetic results.

Influence of different implant placement techniques to improve primary implant stability in low-density bone: A systematic review.

AIM: The aim of this study is to assess the influence of different implant placement techniques to improve primary implant stability (PIS) in the low-density bone. MATERIALS AND METHODS: Citations published in English and those available in full text were searched from electronic databases (PubMed and Google Scholar) from the year 2000-2017 by which 75 manuscripts were revealed. After applying inclusion and exclusion criteria, seven were selected for the present review. The whole process was conducted by the following preferred reporting items for systematic reviews and meta-analyses guidelines. RESULTS: The measurement of primary stability showed significant correlations with different bone densities and with implant outcome; however, these two parameters have not been investigated at the same time frequently. Of the seven manuscripts, three discussed standard drilling protocol, two used undersized drilling, one used guided drilling, and one compared standard drilling with undersized drilling. Several intraoperative methods of jaw bone-density assessment were reported, and resonance frequency analysis, periotest, and insertion torque values were used to quantify PIS. CONCLUSION: The use of undersized drilling has proven advantageous for increasing initial implant stability in the low-density bone. Although the PIS may be lower, the secondary implant stability is found to be correlated to acceptable values.

Comparative evaluation of sagittal inclination of the occlusal plane with Frankfort horizontal plane in facebow transfers to semiadjustable and fully adjustable articulators.

STATEMENT OF PROBLEM: The optimal procedure for the transfer of the sagittal inclination of the occlusal plane (OP) to semiadjustable and fully adjustable articulators is unclear. PURPOSE: The purpose of this clinical study was to evaluate and compare the sagittal inclination of the OP with the Frankfort horizontal plane (FHP) on a facebow transfer to semiadjustable and fully adjustable articulators. MATERIAL AND METHODS: Facebow transfers (Hanau Spring-Bow; Whip Mix Corp) of 30 participants were recorded and transferred to a semiadjustable articulator (Hanau Wide-Vue; Whip Mix Corp) using the indirect method. Another set of facebow transfers from the same set of 30 participants using another facebow (Denar Slidematic Facebow; Whip Mix Corp) was recorded and transferred to a fully adjustable articulator (Denar D5A; Whip Mix Corp). The angle between the OP of the mounted cast and the upper member of the articulator was measured in each participant with a digital protractor on both articulators. Standardized lateral cephalograms of each participant were made as a control. The FHP and OP were traced on each standardized lateral cephalogram. The angle on the cephalogram between the FHP and OP was measured. These values were compared with previously measured values for the Hanau Wide-Vue and the Denar D5A articulators. The data were analyzed using ANOVA. Intergroup comparisons between and among the Hanau Wide-Vue, Denar D5A, and lateral cephalograms were performed using the independent t test. RESULTS: No statistically significant difference was found between the Hanau Wide-Vue and Denar D5A articulators compared with the lateral cephalograms (P=.06). In the intergroup comparison, no statistically significant differences were found between the Hanau Wide-Vue and Denar D5A articulators (P=.18). No statistically significant differences were found between the values obtained on the Hanau Wide-Vue and lateral cephalograms (P=.06). When the Denar D5A articulator was compared with the lateral cephalograms, there was a statistically significant difference (P=.02). CONCLUSIONS: The Hanau Wide-Vue articulator most closely replicated the inclination of the OP. Regarding the sagittal inclination of the OP, the semiadjustable articulator can provide more accurate results than a fully adjustable articulator and thus eliminates occlusal errors.

Evaluation and comparison of different polymerization techniques, curing cycles, and thicknesses of two denture base materials.

PURPOSE: The study aimed to compare the effect of different materials, thicknesses, and polymerization methods and cycles, on the surface porosity of acrylic denture base resins. MATERIALS AND METHODS: Conventional heat-polymerized polymethyl methacrylate (PMMA) and specially designed acrylic resin (Acron MC) were used to make 84 rectangular samples. They were divided into three groups to evaluate and compare the polymerization techniques, curing cycles, and thicknesses of the two denture base materials (28 samples each). Group A contained PMMA samples polymerized using water bath method (control group); Group B contained Acron MC samples polymerized by microwave method, and Group C contained PMMA samples polymerized by microwave method. Each group was further divided based on sample thickness and polymerization cycles. Each sample was scanned for surface porosity and area of each pore was measured using optical microscope. Data was analyzed using ANOVA, Bonferroni, and student t-tests. Unpaired student t-test was performed to compare the means of surface porosity with polymerization cycles and thicknesses among the groups. The power of study was kept at 80%. RESULTS: Group C showed highest mean % of porosity depending on method of polymerization, different polymerization cycles (short and long) and polymerization cycles within the group. Group B showed the highest mean % of porosity depending on thickness and thickness within the groups. CONCLUSIONS: Microwavable acrylic resin polymerized by microwave energy exhibited statistically insignificant increase in porosity when compared to conventional heat cured acrylic resin by water bath method. Conventional acrylic resin polymerized by microwave energy exhibited high statistically significant porosity irrespective of sample thickness. There was statistically insignificant increase in porosity depending on sample thickness irrespective of material and method of polymerization.

Detachable cheek plumpers with different attachments for improving esthetics in a conventional complete denture: A clinical report.

Aging is associated with loss of teeth, resorption of the alveolar process, and reduced tonicity of the facial muscles, leading to sunken cheeks and an unesthetic appearance. Esthetics in patients in need of complete dentures can be improved with the help of cheek plumpers to support the cheeks. They are noninvasive and straightforward to fabricate. Despite the reported success with the sole use of maxillary cheek plumpers, in certain situations, maxillary cheek plumpers provide inadequate support to the cheeks, evident in the lower third of the face. This clinical report describes a technique for fabricating detachable mandibular and maxillary cheek plumpers with 2 different types of attachment mechanisms.

Comparative evaluation of surface porosities in conventional heat polymerized acrylic resin cured by water bath and microwave energy with microwavable acrylic resin cured by microwave energy.

BACKGROUND: Conventional heat cure poly methyl methacrylate (PMMA) is the most commonly used denture base resin despite having some short comings. Lengthy polymerization time being one of them and in order to overcome this fact microwave curing method was recommended. Unavailability of specially designed microwavable acrylic resin made it unpopular. Therefore, in this study, conventional heat cure PMMA was polymerized by microwave energy. AIM AND OBJECTIVES: This study was designed to evaluate the surface porosities in PMMA cured by conventional water bath and microwave energy and compare it with microwavable acrylic resin cured by microwave energy. MATERIALS AND METHODS: Wax samples were obtained by pouring molten wax into a metal mold of 25 mm × 12 mm × 3 mm dimensions. These samples were divided into three groups namely C, CM, and M. Group C denotes conventional heat cure PMMA cured by water bath method, CM denotes conventional heat cure PMMA cured by microwave energy, M denotes specially designed microwavable acrylic denture base resin cured by microwave energy. After polymerization, each sample was scanned in three pre-marked areas for surface porosities using the optical microscope. As per the literature available, this instrument is being used for the first time to measure the porosity in acrylic resin. It is a reliable method of measuring area of surface pores. Portion of the sample being scanned is displayed on the computer and with the help of software area of each pore was measured and data were analyzed. RESULTS: Conventional heat cure PMMA samples cured by microwave energy showed maximum porosities than the samples cured by conventional water bath method and microwavable acrylic resin cured by microwave energy. Higher percentage of porosities was statistically significant, but well within the range to be clinically acceptable. CONCLUSION: Within the limitations of this in-vitro study, conventional heat cure PMMA can be cured by microwave energy without compromising on its property such as surface porosity.

Centric relation definition: a historical and contemporary prosthodontic perspective.

Centric relation (CR) is a core topic of dentistry in general and prosthodontics in particular. The term CR has become thoroughly confusing because of many conflicting definitions. Unfortunately definition of CR changed repeatedly over past ten decades. All the existing definitions in the dental literature, for the past 81 years, are segregated into definitions from 1929 to 1970, 1970-1980, and 1980-2010 and are critically analyzed. Both PubMed (key words: centric relation/centric jaw relation) and hand searches were employed, from citation in other publications, to identify relevant articles in English language peer reviewed PubMed journals from 1956 to 2010; although the review is from 1929. Numerous definitions for CR have been given, however, no consensus exists and the definition given by a current glossary of prosthodontic terms is confusing. It relates CR to many clinically invisible parts and cannot guide a dental surgeon to record the CR following its description. The purpose of this article is not only to review all the definitions critically but to propose a self explanatory definition to minimize the confusion in the minds of dental practitioners and students for better understanding of the concept of CR. Centric relation is clinically significant since it is the only clinically repeatable jaw relation and the logical position to fabricate prosthesis.