Evaluation of Different Beverages’ Effect on Microhardness and Surface Roughness of Different Artificial Teeth

Purpose: This study evaluated the microhardness and surface roughness of four artificial teeth type against various beverages. Materials and Methods: Conventional acrylic resin, reinforced acrylic resin, microfiller composite resin, and nanofiller composite resin teeth were used. From each group, 10 maxillary first and second molars were immersed in 5 beverages (tea, filtered coffee, cola, cherry juice, and distilled water. The test period of 24 hours appears comparable to approximately 1 month of normal beverage consumption. The test periods used in this study were arranged according to this protocol and 1 week, 1 month, 3 months and 6 months of normal beverage consumptions were simulated. Vickers microhardness and surface roughness of denture teeth were measured for each test period. Results: The microhardness values significantly decreased in all beverages especially in 6th month. The surface roughness values significantly increased in all beverages especially in 3th month. There were no statistically significant differences between the beverages. Microfiller composite resin denture teeth had the highest microhardness values and the lowest surface roughness values. Conclusions: Different types of beverages consumed daily negatively affect the microhardness and surface roughness of artificial teeth. Microfiller composite resin teeth could have the ideal surface properties

EFFECT OF SILICA COATING IN ACRYLIC ARTIFICIAL TEETH ON SURFACE ROUGHNESS, CONTACT ANGLE, AND GROWTH OF STREPTOCOCCUS MUTANS

ABSTRACTBackground: Acrylic resin artificial teeth is easily to have bacterial adhesion. It is necessary to perform a treatment on that surface, in order to reduce bacterial adhesion. This study aimed to reveal the effect of silica coating in acrylic resin artificial teeth on surface roughness, contact angle measurement, and the growth of Streptococcus mutans.Method: The study was conducted on two groups (n=16) of disk-shaped acrylic resin artificial teeth with a diameter of 10 mm and thickness of 2 mm. A 2% silica coating material was obtained by diluting 2 g silica nanoparticles on 100 ml of ethanol. Surface roughness, contact angle measurement, and the growth of Streptococcus mutans was measured using surface roughness measuring instrument, camera digital, and colony counter. The data obtained were then analyzed using T-test (p<0.05).Result: The results showed that the surface roughness and contact angle measurement in group I (0.29±0.08 μm); (79,49º ± 10,88º) was higher than group II (0.17±0.05 μm); (34,77º±0,05º). The growth of Streptococcus mutans in group I was also higher (32.28±3.75 CFU/ml) than group II (24.83±3.47 CFU/ml). Conclusion: The study concluded that there is an effect of silica coating on surface roughness, contact angle measurement, and the growth of Streptococcus mutans in acrylic resin artificial teeth.

Speech in phonetics: A review

The proper knowledge of speech production and phonetic parameters will enables the clinician in fabrication of dentures with good phonetic capabilities. In achieving the optimum phonetic potential by providing correlation among three key objectives i.e. (mechanics, aesthetics and phonetics) of dentistry is the eventual goal of every dentist. This article provides a correlation between occlusion and speech, since the time these two factors are mostly not considered related to each other. But during phonation, the lower teeth functions independently and there remain no contact with upper teeth. This article also highlights the basic utilization of phonation as an indispensible part in placement of upper anterior teeth in complete and partial denture rehabilitation. This is basically because, while restoring natural teeth, we may have to depend on pre-extraction records in order to achieve necessary objectives. And if these records are missing, it is difficult to determining the position of artificial teeth. Hence here, we use phonetics as a guideline for proper placement of artificial teeth.

The Use of Polymeric Materials in Modern Dentistry

The achievements and discoveries of chemical science have firmly established themselves in all branches of humanity. One of the most significant chemistry possibilities is the polymerization and polycondensation of compounds, which, in turn, are methods for producing polymers. Polymers are high molecular weight compounds consisting of many units (monomers) linked by chemical bonds. Unique polymer compounds are the basis of plastics, chemical fibers, rubber, paints, and varnishes, adhesives [8]. Polymers are used for the manufacture of removable prostheses, materials for fillings and inlays, orthodontic appliances, artificial teeth, dental implants, as well as in the creation of artificial heart valves, artificial kidney devices, artificial circulation, artificial heart [6].

Myofunctional parameters in patients using full removable dentures with progenic and prognathic ratio of the anterior segments of the edentulous jaws

The aim study was to construct artificial dentitions based on the method of mathematical modeling with the progenic and prognatic ratios of toothless frontal segments and to analyze the functional activity of the masticatory muscles in patients using dentures made in this way, compared with standard prosthetic structures. To compare and interpret the data obtained, electromyographic studies were performed in the control group (16 people), whose teeth were made using the traditional method, and the main group (22 people), whose artificial teeth were formed according to individual mathematical calculations, taking into account the size of the sagittal gap of the frontal segments of the progenic and prognatic ratio of toothless jaws. Statistical processing of the results of the electro-myographic study was carried out using the Statistica application software package. The digital data were processed by the method of variational statistics using the Student's t-test. The analysis of the obtained data showed the advantages of using individual mathematical calculations when solving the issue of tactics for constructing dentitions in the frontal segment of toothless jaws, taking into account the degree of the sagittal gap in the progenic and prognatic correlation of the jaws and their possible combinations.

Evaluation of Color-matching Ability of a Structural Colored Resin Composite

Clinical Relevance Although excellent color-matching ability was confirmed for the structural colored resin composite Omnichroma, care should be taken to ensure that the appropriate chromatic color conditions for restoration are achieved in the oral environment. SUMMARY Purpose: The present study evaluated the color-matching ability of a structural colored resin composite to compare it with resin composites employing pigments. Methods and Materials: A structural colored resin composite (Omnichroma [OMC]), a supranano-filled resin composite (Estelite Σ Quick [ELQ]), and a nano-filled resin composite (Filtek Supreme Ultra [FSU]) were used. Each resin composite was packed into a Teflon mold and pressed down with a clear strip under a glass slide. The specimens were light irradiated through the slide with a light-emitting diode curing unit. The thickness of the specimens (n=6) was measured with a digital caliper before being transferred to distilled water and stored at 37°C for 24 hours. The measurements of the optical characteristics of the specimens on a black-and-white background were performed using a spectrophotometer. D65 (CIE D65) was used as a light source for the spectrophotometer. Measurements were repeated three times for each specimen under each color-measurement condition, and average values for three same-shade specimens were calculated. One-way analysis of variance and Tukey post hoc tests were used (α=0.05). To determine its ability to match the color of artificial teeth, each shade of resin composite was placed in a cavity before performing color measurements. Using a spectrophotometer (CMS-35F S/C) with a flexible sensor, L*, a*, and b* values were obtained. Results: The spectral reflectance curve of OMC showed that it reflected light wavelengths from 430-700 nm regardless of the background color and thickness of the specimens. The percentage of reflectance of ELQ decreased near wavelengths of 550-580 nm. Regarding the influence of background color on CIE L*, a*, b* values, the L* level showed significantly higher values for all tested materials with white backgrounds, and OMC was most affected by the difference in background color. However, a* values of ELQ and FSU were significantly higher with a black background than with a white background, and OMC showed a significantly higher value with a white background than with a black background. The b* values were higher with a white background than with a black background and were significantly higher for all three products, and these tendencies were much greater for ELQ and FSU. Conclusions: The ability of OMC to match the color of artificial teeth showed acceptable color compatibility, regardless of the shade of the artificial teeth and the depth of the cavity. However, ELQ and FSU showed reduced color compatibility, especially for a cavity depth of 3.0 mm. Excellent color matching ability was confirmed for the structural colored resin composite OMC, resulting in reduced color differences and therefore improving the esthetic appearance of the restoration, simplifying shade matching, and compensating for any color mismatch.

Fabrication of Metal-Reinforced Complete Dentures Using the CAD-CAM Technique

The digital manufacture of complete dentures would greatly simplify the workflow; however, the metal-reinforced complete dentures production method has not been well established. This article describes a technique of fabricating metal-reinforced complete dentures in a milling machine using the geometry guide, a negative impression of the occlusal surface of the metal-reinforced complete denture designed using the computer-aided design software. The geometry guide supports and stabilizes the artificial teeth and metal framework in the correct position in the surrounding resin. Fabrication of metal-reinforced dental prosthesis using the digital technique is possible with this method.

Análise da movimentação de dentes de próteses totais polimerizadas com energia de microondas em função da sorção de água: influência da pressão e temperatura

The processing of denture base resins may originate dimensional changes that can alter the occlusal position of artificial teeth of the concluded prosthesis. The polymerization method and the water sorption property of the acrylic resin may cause these changes. Pressure, temperature, and time of water sorption may also have influence on the previous alterations. The aim of this research was to verify the alteration of buccal cusps position of first molars on marillary dentures, polymerized by water bath (9 hours at 76ºC) and microwave energy (3 min at 500W), regarding water sorption under different conditions of time, pressure, and temperature of water storage. Sixty dentures were waxed onto metal die simulating an edentulous maxilla and divided into 4 groups (GI, GII, GIII, and GIV) of 15 samples each. Four different treatments, as follows, were applied to these samples: processing by water bath and stored in water under environmental pressure for 30 days at 37±2ºC (control -GI); processing by water bath and stored in water under 40 pounds for 1 hour at 60±2ºC (Gll): processing br microrwawe energy and stored in water under environmental pressure for 30 days at 37±2ºC(GIII): and processing by microware enerrgy and stored in water under 40 pounds for 1 hour at 60±2ºC (GIV). The degree diferences obtained between the pre and post water sorption were 0.65 for GI; 0.55 for GII; 0.83 for GIII, and -0.57 for GIV (p>0.05). There was significant alteration in the positioning of the artificial firth maxillary molars among the control and the treated storage groups, when cured by microwave energy or water bath.