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.

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 irre- versible 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 parame- ters 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 ex- perimental 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.

Minimizing the risk of fracture of definitive casts for removable partial dentures: A dental technique

A technique is described to facilitate impression making and safely obtain the definitive cast for removable partial dentures with long, retentive, or lone-standing abutment teeth. Firstly, the individualized stock tray receives a coating of melted wax. Next, the prepared teeth are impressed with irreversible hydrocolloid, and the set impression is removed from mouth. The mold is then poured conventionally and, after the gypsum has set, is immersed in hot water to soften the wax and allow removal of the tray. The impression material is carefully cut away with a scalpel blade to expose the cast. With these straightforward and easily made changes compared with the conventional technique, the risk of fracturing the definitive cast is minimized, especially when reproducing long retentive teeth. A dental technique is presented that uses wax to coat the impression tray to facilitate the passive displacement of the cast. This results in a straightforward and precise definitive cast for removable partial dentures.

Implant Impression Making: Take-Off Guide for Beginners

Dental implants are fixtures that constitute for the replacements of the root of a missing natural tooth. Dental implant therapy has been widely used for the restoration of partially and fully edentulous patients. The implant literature emphasizes the importance of a passively fitting prosthesis to prevent prosthodontic complications or even loss of fixture integration. Failure to achieve a passively fitting prosthesis and force tightening of superstructure may result in complications such as abutment, framework, and gold screw loosening or fracture. Various materials that can be used for making an implant impression are polyether, polyvinylsiloxane, condensation silicone, polysulfide, irreversible hydrocolloid material, and various others. There are various studies in relation to the accuracy of these impression materials out of which various scientists concluded different results with most studies stating polyether with the maximum amount of dimensional accuracy in comparison to other materials. An accurate implant impression plays a significant role and serves as a starting point in the process of producing good working casts. Thus, the accuracy of impression techniques becomes a significant issue in consideration of passive fit. Reproduction of intraoral relationship of implants through impression procedures is the first step in achieving accurate fit prosthesis. This transference is still complicated by the number, angulation, depth, and position of implants. The advent of computer-aided design/computer-assisted manufacturing technology improved the framework fabrication procedures and has increased the precision of fit of implant prosthesis.

COMPARISON OF THE ADDITION OF Manihot utilisima (PATI UBI WOOD) TO DIMENSIONAL STABILITY OF IRREVERSIBLE HYDROCOLLOID MOLD

Alginate impression material is used to print the teeth and the oral tissues; alginate molding material is from abroad and expensive. Modification to the impression material alginate with cassava starch with 1: 1 obtained detailed reproduction of the same printed material alginate without added with cassava starch. The study's objective was to get an alternative form of printed material alginate plus Manihot utilisima (cassava starch) with the nature of the physical properties following the standard. The study methods used laboratory experiments. The materials used in this study were printed material alginate (Hydrogum fast setting), starch cassava starch cap dua kelinci, water, and tools calliper inside digital. There were four groups of a control group, a group cassava starch ratio of 50: 50, groups of cassava starch ratio of 60: 40, and a comparison group of cassava starch 70: 30. The results were dimensional stability of printed materials Alginate without additions were (73.72, 48.77, 30.51), the dimensional stability of the printed material alginate with a ratio of 50: 50 were (74.24, 40.82, 30.76), the dimensional stability of the printed material alginate with a ratio of 60: 30 were ( 75.39, 49.67, 31.57), and the results of dimensional stability alginate ((irrevesible hydrocolloid ) molding material with a ratio of 70: 30 were (76.36, 50.94, 32.86). The conclusion is the addition of Manihot utilisima on standard printed material alginate (irrevesible hydrocolloid) obtained dimensional stability test results that met the standards at a ratio of 50: 50 of ANSI/ADA no.18/1992. Manihot utilisima was one of the appropriate alternatives as a mixture in impression material alginate (irrevesible hydrocolloid).

Evaluation of the Physical-Mechanical Properties of Type IV Gypsum

The purpose of this study was to evaluate a physical property (surface roughness) and a mechanical property (microhardness) of four type IV gypsum. 40 specimens were prepared from a metal matrix that reproduced an edentate upper alveolar ridge. They were divided into 4 groups (n = 10 Clone (G3), Durone(G4), SSWhite (G2), Asfer (G1) and submitted to roughness and microhardness tests . The obtained data were submitted to statistical analysis. By the Kolmogorov-Smirnov test it was verified that there was non-parametric distribution of the samples. The non-parametric Kruskal-Wallis and Mann-Whitney-U tests were applied in hardness and roughness data. In microhardness group 3(Clone) presented the best values (103.0 HV). In surface roughness (Ra), group 3(Clone) and Group 2 (SSWhite) showed the lowest values (1.8 m) and all evaluated groups presented higher values than those found in metallic matrix (baseline). It was concluded that gypsum models obtained from molds with irreversible hydrocolloid are rougher than molded surface, regardless of the commercial brand. The samples made with the Clone gypsum (G3) have the highest microhardness. Keywords: Calcium Sulfate. Hardness. Dental Materials. ResumoO objetivo desse trabalho foi avaliar uma propriedade física (rugosidade superficial) e uma propriedade mecânica (microdureza) de quatro marcas comerciais de gesso tipo IV. Foram confeccionados 40 corpos de prova a partir de uma matriz metálica que reproduzia um rebordo alveolar superior edentado. Os mesmos foram divididos em 4 grupos (n=10), de acordo com as marcas comerciais (Clone, Durone, SSWhite, Asfer), e submetidos aos testes de rugosidade e microdureza superficial utilizando um rugosímetro e um microdurômetro respectivamente. Os dados obtidos foram computados e submetidos à análise estatística. Pelo teste de Kolmogorov-Smirnov verificou-se que não houve distribuição Normal das amostras. Dessa forma foram aplicados os testes não paramétricos de Kruskal-Wallis e Mann-Whitney-U em ambas as análises. Na microdureza, a marca comercial Clone apresentou os melhores valores (103,0). Já na rugosidade superficial as marcas comerciais Clone e SSWhite apresentaram os menores valores (1,8). Ainda em relação à rugosidade superficial, as marcas comerciais avaliadas apresentaram valores maiores que os encontrados na matriz metálica. Concluiu-se que modelos em gesso obtidos a partir de moldes com hidrocolóide irreversível apresentam-se mais rugosos que a superfície moldada, independente da marca comercial avaliada. Os modelos em gesso confeccionados com a marca Clone apresentam melhor microdureza superficial. Palavras-chave: Sulfato de Cálcio. Dureza. Materiais Dentários.

POSSIBILITIES FOR MODIFICATION OF SURGICAL OBTURATOR INTO TEMPORARY OBTURATOR

Background: Maxillary resection causes different types of damages in the maxillofacial area, which are treated by surgical and prosthetic restorative methods. Aim: The described clinical case follows up the initial stages of the prosthetic treatment, as well as the possible modification of surgical obturator into temporary obturator in a patient with maxillary resection. Materials and methods: The prosthetic treatment of a 55-years-old female patient with a surgical operation of upper jaw cancer is described. The surgical obturator is developed a week after the resection. The preliminary impressions are taken with irreversible hydrocolloid impression material. The occlusion height and central relation are fixed by occlusion rims. The surgical obturator was fabricated by heat cured acrylic resin with a low amount of residual monomer. Moreover, metal clasps were used for retention and stability. The borders of the obturating part were covered with a thin layer of relining silicone material after the adjustment. The surgical obturator was modified into a temporary one directly in the patient's mouth after two months by applying the same rebasing material and designing a silicone hollow-bulb obturating part. Results: The treatment results revealed a successful restoration of the patient's speaking, feeding, and swallowing abilities. The application of silicone material inhibited the appearance of decubitus ulcers and facilitated the normal healing process. The direct design of hollow-bulb silicone obturating part significantly improved the retention and stability of the obturator. Conclusion: The application of prosthetic treatment methods in the first days after the maxillary resection allows for restoration of speaking and feeding.