Panacea to lost gingival tissue architecture and spacing: Silicone gingival prosthesis.

The positive psychological effects of improving patients' smile often contribute to an improved self-image and enhanced self-esteem. Periodontal disease may lead to tooth and tissue loss that can result in esthetic problems. Combined periodontal/prosthodontic treatment for patients with advanced disease is well documented. This case report illustrates a method of treatment for an advanced tissue loss in an esthetic area using a removable silicone gingival prosthesis/mask.

Scanning electron microscopic evaluation of root canal surfaces prepared with three rotary endodontic systems: Lightspeed, ProTaper and EndoWave.

BACKGROUND AND OBJECTIVES: The purpose of this in vitro study was to evaluate and compare the cleaning efficiency, preparation time, instrument deformation and fracture with LightSpeed (LS), ProTaper (PT) and EndoWave (Ew) rotary instruments. MATERIALS AND METHODS: A total of 45 freshly extracted human mandibular premolars were subjected for the study. They were divided into three groups, each group consisting of 15 teeth. Group 1: The canals were prepared with LS system; Group 2: PT rotary system, Group 3: Ew rotary system. All the groups were prepared according to manufacturer's recommendation, using 5.25% sodium hypochlorite and 17% ethylenediaminetetraacetic acid (dent wash, prime dent) alternately as an irrigants. Crowns of each tooth were removed with diamond disks at the level of cemento enamel junction. Canal length was determined by placing a size 10 K-file. The working length was 0.5 mm short of canal length. Two longitudinal grooves were prepared on the lingual and buccal surfaces of each root to facilitate vertical splitting with a chisel after canal instrumentation. The sections were then observed under scanning electron microscope for presence or absence of debris and smear layer and the photographs were taken at coronal, middle and apical 1/3 with a magnification of × 200 and × 1000 respectively. The time taken to enlarge each canal was recorded in minutes and seconds. The instruments were examined after every use for deformation. The scores recorded were statistically analyzed using one-way analysis of variance and Mann-Whitney test. RESULTS: There was statistically significant difference with regard to removal of debris and smear layer at coronal, middle and apical third for LS versus PT and LS versus Ew (P < 0.01). There was no significant difference between PT and Ew. The mean preparation time for LS, PT and Ew was 1.76, 2.50 and 2.75 respectively. INTERPRETATION AND CONCLUSION: The study demonstrated that, LS instrumentation removed debris and smear layer effectively with shorter preparation time and Ew instrument showed deformation.

An in vitro study of the effect of design of repair surface on the transverse strength of repaired acrylic resin using autopolymerizing resin.

STATEMENT OF PROBLEM: The fracture of complete denture is a common occurrence in the field of prosthodontics. Often if all other criteria are met such as good aesthetics, occlusion, and functionality; denture repair is acceptable. Once denture fractures, we would want the joint surface strength to be as good as original. PURPOSE: The purpose of this study was to determine the effect of different repair surface design on the transverse strength of repaired acrylic denture resin. MATERIALS AND METHODS: Sixty specimens of heat-cured acrylic resin of dimension 65 mm × 20 mm × 2.5 mm were prepared using a special die. Transverse strength of 15 samples was calculated which serves as a control group. Three different types of joint surface contours were prepared each having 15 samples each as butt, round, and rabbet joint. Transverse strength of three joint contours was then compared with control group and also they were compared with each other and result was statistically analyzed with one-way analysis of variance (ANOVA) and Post-hoc ANOVA Tukey's HSD test at 5% level of significance. Z-test of proportion was also done for types of failures. RESULT: Transverse strength of original specimen was higher than that of repaired specimens. Transverse strength of round joint was higher than the butt and rabbet joint. CONCLUSION: Methods of repair have significant effect on strength of repaired denture. Round joint design of repair technique was far superior.

Effect of denture cleanser on weight, surface roughness and tensile bond strength of two resilient denture liners.

AIM: Evaluating effects of a denture cleanser on weight, surface roughness and tensile bond strength on two resilient lining materials. MATERIALS AND METHODS: Specimens of heat cure acrylic resin were prepared to verify weight change, surface roughness and tensile bond strength. Specimens were divided into four groups: Relined with resilient liner Visco-gel, soft liner immersed in Clinsodent denture cleanser and water and evaluated immediately, 24 hours, 7 and 15 days. Weight changes, roughness and tensile bond strength were determined and data submitted to statistical analysis. RESULTS: Visco-gel specimens immersed in water (group 1) have shown significant increased surface roughness than those immersed in Clinsodent (group 3) during 24 hours, 7 and 15 days. The soft liner specimens immersed in water (group 2) have shown increased surface roughness than those immersed in Clinsodent (group 4) during 24 hours and 7 days. Visco-gel specimens immersed in water have shown significant increased tensile bond strength during 7 and 15 days than those immersed in Clinsodent. The soft liner specimens immersed in water have shown increased tensile bond strength than those immersed in Clinsodent during immediately, 24 hours and 7 days. CONCLUSION: Within limitations of this study, specimens immersed in Clinsodent demonstrated increased weight changes compared with water. Specimens immersed in water demonstrated lesser surface roughness and tensile bond strength compared with specimens immersed in Clinsodent. CLINICAL SIGNIFICANCE: Resilient denture liners and denture cleansers are most commonly used materials in prosthodontics. Caution should be taken while selecting the materials which cause the detrimental changes on properties of the materials.

Infrared thermographic evaluation of rise in temperature with conventional versus trephine drills.

Aim: To compare the rise in temperature using trephines over conventional ones during bone site preparation. Setting and Design: An-vitro, evaluative study. Materials and Methods: Twenty implant sites were prepared using pilot drill up to depth of 10 mm on bovine femoral bone. In first part, no irrigation was used. Five sites were prepared using conventional drill of 2.8 mm, and other five were prepared with help of trephine drills. On completion of each drill, infrared thermometer was used to measure temperature on both the drill tip and the shaft. The same procedure was repeated with bone immersed in saline. Statistical Analysis Used: Student t test was used to evaluate the significance of difference. Result: Study showed that the temperature rise at drill tip was significantly higher for trephine drill (52.98 ± 1.67 °C) than conventional drills (48.20 ± 0.67 °C), however the temperature difference in trephine and conventional drills was statistically insignificant. Conclusion: The temperature increase was more distributed in conventional drills than trephine. Copious irrigation is thus mandatory for trephine drills. Intermittent drilling is preferred with conventional drills.

Comparative Evaluation of Effect of Water Absorption on the Surface Properties of Heat Cure Acrylic: An in vitro Study.

BACKGROUND: Use of alkaline peroxide denture cleanser with different temperature of water could cause a change in surface hardness of the acrylic denture and also has a bleaching effect. The purpose of the study was to determine the effect of increased water content during thermal cycling of hot water-treated acrylic on the surface hardness of acrylic denture base when compared to warm water treated acrylic. And to compare the bleaching effect of alkaline peroxide solution on the acrylic denture base on hot water and warm water treated acrylic. MATERIALS AND METHODS: Forty samples (10 mm × 10 mm × 2.5 mm) were prepared. After the calculation of the initial hardness 40 samples, each was randomly assigned to two groups. Group A: 20 samples were immersed in 250 ml of warm distilled water at 40°C with alkaline peroxide tablet. Group B: 20 samples were immersed in 250 ml of hot distilled water at 100°C with alkaline peroxide tablet. The surface hardness of each test sample was obtained using the digital hardness testing machine recording the Rockwell hardness number before the beginning of the soaking cycles and after completion of 30 soak cycles and compared. Values were analyzed using paired t-test. Five samples from the Group A and five samples from Group B were put side by side and photographed using a Nikon D 40 digital SLR Camera and the photographs were examined visually to assess the change in color. RESULTS: Acrylic samples immersed in hot water showed a statistically significant decrease of 5.8% in surface hardness. And those immersed in warm water showed a statistically insignificant increase of 0.67% in surface hardness. Samples from the two groups showed clinically insignificant difference in color when compared to each other on examination of the photographs. CONCLUSION: Thermocycling of the acrylic resin at different water bath temperature at 40°C and 100°C showed significant changes in the surface hardness.

Evaluation and comparison of resistance to compression of various interocclusal recording media: an in vitro study.

BACKGROUND: This in vitro study was conducted to compare the compression resistance of various interocclusal recording materials when subjected to a compressive load. MATERIALS AND METHODS: Each interocclusal recording material was manipulated according to the manufacturer instruction and placed into a metallic cylinder. A total of 20 specimens for each interocclusal recording material were made. A total 100 specimens were fabricated. Each specimen was placed in the Universal Testing Machine exerting pressure on it, and a force of 100 g/cm(2) was exerted on each sample. 30 s later the reading of the Universal Testing Machine was recorded using a vertical traveling micrometer microscope with an accuracy of ± 0.001 mm. This value was marked as reading "A." 60 s after the application of the first force (100 g/cm(2)), a second force of 1000 g/cm(2) was applied gradually during an interval of 10 s. 30 s later the reading of the Universal Testing Machine exerting pressure on the specimen was recorded again. This value was marked as reading "B." The difference between readings "A" and "B" recorded the compression to resistance of each material. Comparisons within the groups and between the groups were done by using one-way ANOVA and Tukey's HSD test. RESULT: There was significant variation between all interocclusal bite registration materials. According to the mean valve of each interocclusal bite registration material, Polyvinylsiloxane Bite Registration Material have better resistance to compression followed by Polyether interocclusal bite registration material, Aluwax Bite, and Impression Wax, Modeling Wax and at last Zinc Oxide Eugenol Impression Paste. CONCLUSION: Polyvinylsiloxane interocclusal registration material had the greatest resistance to compression. The least resistance to compression was noticed with zinc oxide-eugenol paste.

Scanning Electron Microscopic Evaluation of Root Canal Surfaces Prepared with LightSpeed & Endowave Rotary System.

BACKGROUND AND OBJECTIVES: The purpose of this in vitro study was to evaluate and compare the cleaning efficiency on root canal surfaces prepared with LightSpeed and Endowave rotary instruments. MATERIALS AND METHODS: A total of 30 freshly extracted human mandibular premolars were subjected for the study. They were divided into two groups, each group consisting of 15 teeth. Group 1: The canals were prepared with LightSpeed system. Group 2: Endowave rotary system. All the groups were prepared according to manufacturer's recommendation, using 5.25% sodium hypochlorite and 17% EDTA (dent wash, prime dent) alternately as an irrigants. Crowns of each tooth were removed with diamond disks at the level of cement enamel junction. Canal length was determined by placing a size 10 K-file. The working length was 0.5 mm short of canal length. Two longitudinal grooves were prepared on the lingual and buccal surfaces of each root to facilitate vertical splitting with a chisel after canal instrumentation. The sections were then observed under SEM for presence or absence of debris and smear layer and the photographs were taken at coronal, middle and apical 1/3 with a magnification of 200 X and 1000X respectively. The scores recorded were statistically analysed using one-way-ANOVA and Mann- Whitney test. RESULTS: There was statistically significant difference between two groups. All groups resulted in significantly more debris and smear layer in the apical 1/3 of the canal, compared to coronal and middle 1/3 (p, <0.01). INTERPRETATION AND CONCLUSION: The study demonstrated that, LightSpeed instrumentation removed debris and smear layer more effectively on root canal surface than compared to Endowave instrument.