| Background: removable partial denture and complete denture in the mouth after months of use, because the role in denture masticatory pressure stimulation of alveolar bone, make its produce different degrees of absorption, and widen the gap between the mucosa and denture surface adsorption capacity decreased, resulting in poor denture retention, denture should be necessary at this time processing to compensate for the alveolar ridge absorption of voids appear. Methods for treating the most simple, fast, cheap is the choice of soft lining materials were relining, not only solved the difficult cases, and better long-term results. But in the process of use, easy to adhesion of bacteria and fungi, resulting in oral local flora imbalance, caused some oral diseases such as dental caries incidence, periodontal disease, denture stomatitis and etc.. Therefore, the preparation has high antibacterial properties of soft lining materials, reduce the occurrence of oral diseases, improve curative effect of denture has become the focus of many of today’s research attention.At present, the clinical commonly used to improve the performance of soft liner materials antibacterial methods have mechanical cleaning method, microwave disinfection, ultraviolet radiation, chemical immersion and adding organic antibacterial agent, etc., but these methods there are antibacterial maintain short time, reduce the use of soft liner materials performance, high temperature resistant, etc.Experiments show that, in some commonly used oral materials(soft, soft lining) after adding nanometer antibacterial agent, material antimicrobial properties are increased obviously. So in recent years, more and more scholars try to join in soft liner materials nano inorganic antibacterial agent to improve the antimicrobial properties of materials. This kind of antibacterial agent including antimicrobial ability of nano-silver antibacterial agent and the action faster, antibacterial time longer titanium dioxide photocatalytic antibacterial agent. But the product of the combination of the two silver nano titanium dioxide as material in the field of research and development of literature in the field of it used in dental restorations.Objective: this experiment to the clinical commonly used two kinds of soft denture liner material add loading silver nano titanium dioxide(Ag-TiO2) after antibacterial agent, antibacterial ability, the bond strength of research materials and shaw hardness is how to change, to provide experimental basis for the application of materials in the future.Methods:(1)under normal temperature will be silver nano TiO2 powder according to the different proportion of 0-4%, respectively, to be added to the SOFRELINER MEDIUM material and self-curing soft liner. Simulated denture made corresponding specifications of the soft lining specimen surface, in which the experimental group for silver nano TiO2 addition amount for 1-4% each of seven groups, did not join the antibacterial agent(0%) of the two kinds of soft lining materials of various soft lining material of the blank control group respectively. All samples of high temperature sterilization, then infected with candida albicans, USES the membrane method of constant temperature culture after 24 h, and then add 10 ml sterile saline water were taken to each tablet, violent oscillation on the generator 1 min, completely remove adhesion on the surface of the specimen and PE membrane, calls. Fully blending rinses, using the method of increasing 10 times dilution to 1 x 2, 10-100 ul inoculation on the solid medium, thermostatic cultivation for 24 hours, counting the number of bacteria, the above methods do 3 times, the average 3 set of data together. Into the calculation formula of antibacterial rate: R % =(A: blank control sample average recovery of bacterial count(CFU/piece)- B: antibacterial sample average recovery of bacterial count(CFU/film)) x 100 / A, R represents the antibacterial rate(%). Through experiments to detect join antibacterial antibacterial rate of two kinds of soft liner materials whether has antibacterial effect and the influence of adding amount of antibacterial effect(2) with the help of a good preparation in advance 24 hole diameter of 8 mm stainless steel abrasive preparation, high to 10 mm(4 mm + 2 mm + 4 mm) of the cylinder specimen of soft lining materials in both of 48, according to the different mass fraction is divided into eight groups, and fix the specimen universal material testing machine for tensile test, measurement of soft lining specimen from the resin surface rupture strength on behalf of the tensile strength, record when fracture of the value of P(N), in the following formula b = P/PI r2 calculated maximum tensile strength(MPa) b. After fracture of specimens in the asana microscope and photographed breaking records.(3) according to the GB/T531-1992 "determination of vulcanized rubber shaw A hardness standard, soft lining materials in both of the preparation of 35 mm * 15 mm * 6 mm specimen 48, divided into 16 groups, each group of three, the specimen has A smooth surface and that there are no bubbles. Put the sample in smooth, thickness > 5 mm on the glass plate, glass plate parallel to the ground. Will shaw A hardness tester of the pressure needle to vertical force into the surface of specimen, when the pressure of the spring and reaction phase equilibrium. Record as a result, to study the antibacterial agent of two kinds of soft liner materials mechanical performance will be what kind of impact.Results:(1) the antibacterial experiment results show that 1-4% and 0% group had significant difference(p < 0.05). Antibiotic dose within a certain range, with the increase of antibacterial agent content, two kinds of soft liner materials antibacterial rate is gradually rising trend. Silver nano TiO2 adding amount was 2%, the antibacterial rate of candida albicans were greater than 80%. At the same time can be seen from the experimental data of specimens before and after aging treatment antibacterial rate of change is very small, do not have statistical significance(p > 0.05), so join AgTiO2 antibacterial agent of the two kinds of soft liner materials not only has the antibacterial effect and long-term. At the same time to add the same proportions self-curing soft liner antibacterial rate is slightly higher than silicone rubber.(2) in accordance with the relevant national standards testing different mass fraction of silver nano TiO2 antibacterial agent of two kinds of soft liner materials mechanical properties of the tensile strength, fracture, shaw hardness changes, the results show that this kind of antibacterial agent within a certain range of two kinds of soft liner materials mechanical properties are improved. When antibacterial agent to add mass fraction is 3%, the tensile strength of two kinds of soft liner materials peak namely optimal value, and under the adding amount, silver nano titanium dioxide in since the mechanical action of soft liner than silicone rubber effect is obvious.(3) the two materials of shaw hardness value as the amount of silver nano TiO2 to add more gradually up.Conclusion: 1. Add the silver nano TiO2 antibacterial agent of both soft lining materials have the function of the resistance of candida albicans, antimicrobial rate rises with the increase of adding antibacterial proportion, and through comparison before and after aging treatment both soft lining material have antibacterial longer. 2. The two kinds of soft liner materials tensile strength value, first with the increase of antibacterial agent mass fraction after rising downward trend. Shaw hardness is a trend of rising. 3. When the silver nano TiO2 added mass fraction was 3%, two kinds of soft liner materials not only has strong antibacterial properties, and obtained the high mechanical performance, is this topic in the end it is concluded that the best proportion of Ag-TiO2 antibacterial agent added value. |
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