A Clinical Comparative Study of Two Different Materials Used in Recording Neutral Zone in Completely Edentulous Patients at Jaipur Dental College, Jaipur.

Stability of mandibular dentures in highly resorbed ridges is a great challenge and one of the deciding factors in the failure or success of the complete denture. The neutral zone technique is an alternative approach for the construction of complete dentures with such kind of challenges. The objective of this research was to study the accuracy of reproducibility of Neutral Zone by two commonly available dental materials, tissue conditioner and zinc oxide eugenol paste.METHODSViscogel tissue conditioner and zinc oxide eugenol paste are easy flowing recording materials and can be recorded by using support. Hence to study the accuracy of the reproducibility of the neutral zone, specially designed acrylic rims with occlusal stops were used which supported the recording materials adequately in the posterior region of the inter ridge space. Swallowing method was used to record the neutral zone, five times by each material. Bucco-lingual dimension of the neutral zone was recorded at predetermined reference points for all individuals with the help of a micrometer. 40 patients were selected with Class 1 jaw relations.RESULTSIn this in vivo study done in selected 40 patients, selection done according to selection criteria to compare the accuracy of reproducibility of Neutral Zone by tissue conditioner [Dentsply, Visco-gel, Temporary Soft Denture Liner]and zinc oxide eugenol impression paste [DPI Impression Paste R]. Neutral zone were recorded in all the cases with both materials and data recorded to create the results. By summarizing the results as width (in mm.) of the neutral zone at point 1, 2, 3, and 4 for tissue conditioner [Dentsply, Visco-gel, and Temporary Soft Denture Liner] were 10.36, 10.06, 10.51 and 10.21 respectively. For zinc oxide eugenol impression paste [DPI Impression Paste R] at point 1, 2, 3, and 4 width was 10.95, 10.44, 11.16 and 10.67 respectively. Calculated Coefficient of Variance value with Viscogel tissue conditioner is 0.70 % and with zinc oxide eugenol paste 1.04 %.CONCLUSIONWith these results and statistical analysis, with 5% of level of significance (as alpha = 0.05) i.e. 95% confident, we found enough evidence to conclude that usage of Viscogel tissue conditioner is more effective and accurate than zinc oxide eugenol impression paste in neutral zone technique.

Evaluation of Bond Strength of Silicone and Acrylic Resin Based Resilient Denture Liners Over A Period of Storage in Water

Background: Two potential problems commonly identified with a denture base incorporating a resilient liner are afailure of the bond between the acrylic resin and resilient liner material and a loss of resiliency of the resilient liner material over time. Methods: The current study was performed to assess the bond strength and hardness of acrylic resilient liner in both auto-polymerized and heat-polymerized forms and silicone resilient liner in auto-polymerized form to a processed denture base resin over a period of water storage for 1 day, 1 week and 1 month. The denture liners investigated were acrylic resin-based heat-polymerized (Super-soft), acrylic resin-based autopolymerized (Coe-Soft) and silicone based autopolymerized (GC-reline) resilient liner. The resilient liners were processed according to manufacturer’s instructions. Tensile bond strength was measured in ASI Instron universal testing machine at a crosshead speed of 20 mm/min, and hardness was measured using a Shore-A durometer. Results: Two-way ANOVA and Tukey HSD tests were used to analyze the data (α=0.05). The results indicated that there were significant differences both in the hardness and bond strength values of resilient liner materials. Conclusion: Autopolymerized silicone resilient liner has increased bond strength and hardness values than autopolymerized acrylic liner but the bond strength and hardness values of autopolymerized silicone liner was less than heat cure acrylic resilient liner.

Preliminary study on the clinical application of temporary treatment denture in difficult edentulous cases before complete denture restoration / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To explore the clinical effects of treatment denture on difficult edentulous cases before complete denture restoration.</p><p><b>METHODS</b>Thirty-six patients who experienced unsuccessful restoration of conventional complete dentures were included in this study. Treatment dentures were fabricated to solve issues such as abnormal occlusion, tissue surface problems, and neuromuscular dysfunction of the stomatognathic system caused by systemic diseases. The final complete dentures were fabricated by duplicating the treatment dentures. Jaw relation index, stability, and retention were evaluated at different stages. Oral health-related quality of life was measured using the Chinese version of Oral Health Impact Profile for edentulous subjects (OHIP-EDENT).</p><p><b>RESULTS</b>Among the 36 patients, 33 successfully completed the final restoration with positive effects.</p><p><b>CONCLUSIONS</b>Treatment denture is an effective pre-restorative option that can be used to correct abnormal occlusion, improve tissue surface problems, and aid in neuromuscular rehabilitation training. Treatment dentures contribute to the successful restoration of the final complete dentures and is worthy of clinical applications.</p>

The evaluation of the amount and sustain release of antifungal agent clotrimazole incorporated in different polymer matrix in artificial saliva at a pH of 6.2.

Background: Candidiasis in the oral cavity is an opportunistic infections, the most common species involved is Candida albicans. Clotrimazole (CTZ) is the first line broad-spectrum antifungal drug that has been widely used for the prophylaxis and treatment of oral and vaginal candidiasis. It is seen that the effect of drug is better locally as compared to oral intake. The aim of the present study is to find out the quantum release of clotrimazole from the incorporated materials in the artificial salivary medium at the pH of 6.2 and to access the physical properties of the clotrimazole incorporated reliner and tissue conditioner. Methods: The antifungal clotrimazole is incorporated in two types of denture base material used for this study at 2%, 5% and 10% concentration by weight. The release of clotrimazole out of polymer matrix was studied at various pH. The main property of tensile strength of the specimen before and after the chemical release of the clotrimazole was tested. Result: Concentration was maximum on 8th day and uniformly decreased thereafter. The maximum amount of release upto 8th day was 2.52, 4.23, 9.84 mg for 2%, 5% and 10% respectively. Conclusion: Topical release of antifungal agents is more effective than systemic intake, which has adverse effect like renal toxicity and CNS toxicity.

Functionally Generated Amalgam Stops For Single Complete Denture : A Case Report.

Single complete denture opposing natural dentition is a common occurrence in clinical practice. Malposed, tipped or supraerupted teeth in the opposing arch is a perplexing problem in achieving a harmonious balanced occlusion in single complete denture patients . It is developed for stability of denture bases in relation to supporting structures during functional and parafunctional movements. Lack of occlusal balance may lead to denture instability, mucosal soreness, tissue changes and accelerated ridge resorptionThe single complete denture with a technique of occlusal refinement by functionally generated amalgam stops condensed in prepared resin teeth after initial balancing of the denture with semiadjustable articulator. This technique provides intimacy of contact in all excursions by carving the amalgam in plastic stage. Amalgam stops improve the efficiency of the resin teeth. Dentures fabricated using this technique require fewer and simpler post-insertion adjustment.

Patient Satisfaction With Complete Denture Fabrication Using Two Neutral Zone Impression Materials - An Invivo Study.

The concept of Neutral zone is an important biomechanical consideration in fabrication of complete dentures. There are different methods of recording the Neutral zone. This article compares the levels of patient satisfaction with complete denture fabricated using two neutral zone impression materials.

Implant overdenture impressions using a dynamic impression concept

A dynamic impression is a functional impression that records the functional movement of the patient's own muscle and muscle attachment. This process reduces the number of random factors. This article describes a method for making a special tray using a dynamic impression concept that was made from provisional dentures used for implant healing. The individual tray is used to make a wash-impression to record the features of the mucosa in detail. The main advantage of this technique is that it provides a functional relationship of the implant components to the supporting tissues without overextension because provisional denture had been used for 2 months and the border length of individual tray was nearly the same as that of provisional denture. The delivery of the prosthesis constructed using this impression technique is time-saving because there is no need for border molding and there are fewer post-insertion appliance adjustments.

The effectiveness of magnesium oxide combined with tissue conditioners in inhibiting the growth of Candida albicans: An in vitro study.

Context : The presence of Candida albicans on the fitting surface of the denture is a major causative factor in denture stomatits. A treatment method is by combining tissue conditioner and antifungal agents. Aims : The main objective of this study is to test the efficacy of magnesium oxide combined with two tissue conditioners (Viscogel and GC Soft), in inhibiting the growth of Candida albicans. Settings and Design : Microbiological study was done in the Department of Microbiology, K S Hegde Medical Academy, Nitte University, Mangalore. Materials and Methods : A total of 154 plates were prepared using Muller Hilton with Glucose and Methylene Blue dye medium and inoculated with 24-hr old standard Candida culture. Plates were divided into control and combination. Test discs with different concentrations of MgO were equidistantly placed in MgO Control, while sterile discs embedded with respective tissue conditioner were equidistantly placed in Viscogel and GC Soft controls. For combination groups, the tissue conditioners were mixed and the discs with MgO (1%, 3%, 5%, and 7%) were embedded in the mix. After 24 h of incubation, inhibition diameters were noted. Statistical Analysis Used : The data was analysed using Mann Whitney U Test, ANOVA, Tukey HSD test. Results : The inhibition effect of magnesium oxide 1% combined with tissue conditioners (VGC and GCC) is not significant in both the groups. The inhibition effect of MgO 5% and 7% combined with tissue conditioners (VGC and GCC) is very highly significant ( P < 0.001). Conclusions : Magnesium oxide in combination with tissue conditioners are effective against Candida albicans; GC soft with magnesium oxide showed a better result than Viscogel with magnesium oxide; Increasing the concentration of magnesium oxide increases the zone of inhibition of Candida albicans.

In vitro antimicrobial effect of the tissue conditioner containing silver nanoparticles

PURPOSE: The aim of this study was to identify in vitro antimicrobial activity of the tissue conditioner containing silver nanoparticles on microbial strains, Staphylococcus aureus, Streptococcus mutans and Candida albicans. MATERIALS AND METHODS: Experimental disc samples (20.0x3.0 mm) of tissue conditioner (GC Soft-Liner, GC cooperation, Tokyo, Japan) containing 0.1 - 3.0% silver nanoparticles (0%: control) were fabricated. Samples were placed on separate culture plate dish and microbial suspensions (100 microL) of tested strains were inoculated then incubated at 37degrees C. Microbial growth was verified at 24 hrs and 72 hrs and the antimicrobial effects of samples were evaluated as a percentage of viable cells in withdrawn suspension (100 microL). Data were recorded as the mean of three colony forming unit (CFU) numerations and the borderline of the antimicrobial effect was determined at 0.1% viable cells. RESULTS: A 0.1% silver nanoparticles combined to tissue conditioner displayed minimal bactericidal effect against Staphylococcus aureus and Streptococcus mutans strains, a 0.5% for fungal strain. Control group did not show any microbial inhibitory effect and there were no statistical difference between 24 hrs and extended 72 hrs incubation time (P > .05). CONCLUSION: Within the limitation of this in vitro study, the results suggest that the tissue conditioner containing silver nanoparticles could be an antimicrobial dental material in denture plaque control. Further mechanical stability and toxicity studies are still required.

Changes of the surface roughness depending on immersion time and powder/liquid ratio of various tissue conditioners / 대한치과보철학회지

STATEMENT OF PROBLEM: Volume stability, microstructure reproducibility and fluidity along with compatibility with dental stone must be in consideration in order to use tissue conditioner as a material for functional impression. There are few studies concerning the influence of time factor in oral condition on surface roughness of the stone and optimal retention period in the oral cavity considering such changes in surface roughness. PURPOSE: The purpose of this study was to find out the influence of various kinds of tissue conditioner, its powder/liquid ratio and immersion time on surface roughness of the stone. MATERIAL AND METHODS: Materials used in this study were the three kinds of tissue conditioners (Coe-Comfort, Visco-Gel, Soft-Liner) and were grouped into three: group R - mixed with standard powder/liquid ratio that was recommended by the manufacturers, group M - mixed with 20% more powder, group L - mixed with 20% less powder. Specimens were made with the size of 20 mm diameter and 2 mm width. Each tissue conditioner specimens were subdivided into 5 groups according to the immersion time (0 hour, 1 day, 3 days, 5 days, 7 days), completely immersed into artificial saliva and were stored under 37degrees C. Specimens of which the given immersion time elapsed were taken out and were poured with improved stone, making the stone specimens. Surface roughness of the stone specimens was measured by a profilometer. RESULTS: Within the limitation of this study, the following results were drawn. 1. Major influencing factor on surface roughness of the stone model made from tissue conditioner was the retention period (contribution ratio (rho) = 62.86%, P < .05) of the tissue conditioner in oral cavity to make functional impression. 2. In case of Coe-Comfort, higher mean surface roughness value of the stone model with statistical significance was observed compared to that of Soft-Liner and Visco-Gel as immersion time changes (P < .05). 3. In case of group L (less), higher mean surface roughness value of the stone model with statistical significance was observed compared to that of R (recommended) and M (more) group as immersion time changes (P < .05). CONCLUSION: We may conclude that as the retention period of time in oral cavity influences surface roughness of the stone model the most and as the kind of tissue conditioner and its P/L ratio may influence also, clinician should well understand the optimal retention period in oral cavity and choose the right tissue conditioner for the functional impression, thus making the functional impression with tissue conditioner usefully.

A study on the visco-elastic properties of four currently used tissue conditioners / 대한치과보철학회지

The dimensional stability of tissue conditioners characterizes the ability of the materials to yield accurate functional impressions of oral mucosa. This study evaluated the viscoelastic property and the linear dimensional changes with the factor of time and thickness of tissue conditioners (COE-COMFORT(TM), Visco-gel, COE-SOFT(TM), Soft-Liner) The thickness of these materials were changed (1.5mm, 3.0mm) and the percentage changes in dimension were measured at 1h, 12h, 24h, 36h, 3day, 7day after specimen preparation. From the results large differences appear between the various tissue conditioners. The results suggest that the period recommended for forming functional impression would be 2-3days after insertion in the mouth. in addition, it is important to select tissue conditioners suitable for functional impression because of the wide range of dimensional stability among the materials.