Background: The denture base inaccuracies during processing negatively influence the retention and stability of finished complete denture. The aims of this study were to evaluate teeth movement and palatal adaptation of autoclave cured denture bases and their relationship with palatal depths and investments. Materials and methods: A nightly maxillary complete dentures prepared, processed and organized to be tested as follows: 1. Processing methods: water bath and autoclave with both fast and slow cycles. 2. Palatal depth: shallow, medium and deep. 3. Investing medium: stone and silicone. For every finished denture, two measurements were done: first: teeth movement by attaching metallic reference screws on the right and left centrals, first premolars and second molars. Second: palatal adaptation by sectioning the posterior part of the denture and measuring the distances between five selected points which were on the right and left: ridge crest, center of the vestibule and middle of the palate. Then two measurements were done before and after curing by using travelling microscope of 0.001% of accuracy. The collected data organized statistically by three ways analysis of variance for curing methods, investments and palatal depth. Also, least significant test and t test for detection of difference. Results: High significant improvements in dimensional stability shows when autoclave was used compared with the water bath. Results show that autoclave curing reduces the amount of teeth movements and improves palatal adaptation with silicone investment compared with stone. Conclusions: resin curing by autoclave is a better alternative to water bath. The dimensional stability were improved especially when silicone were used instead of stone. Key words: Teeth movements, palatal adaptation, silicone investment, travelling microscope.
Background: Change in palatal vault shape and Reinforcement of high impact acrylic denture base resin may in turn affect the dimensional accuracy of acrylic resin and affecting the fitness of the denture.This study evaluated tostudy the effect of fiber reinforcement for high-impact acrylic resin denture base with different palatal vault shapes on adaptation or gap space between the denture base and the stone cast and compare with non-fiber reinforcement and effect of palatal vault shapes on adaptation of non-reinforced and fiber reinforced high impact denture base acrylic resin Material and method: Three different palatal vault shapes were prepared on standard casts using CNC (computer numerical control) machine. 60 samples of heat polymeri
... Show MoreObjective(s): The world of dentistry is constantly evolving, and with the advent of 3D printing technology, the possibilities are endless. However, little is known about the effects of adding ZrO2 NPs to the denture base resin of 3D additive manufacturing technique.Aim of this study is to evaluate the behavior of resin which is used to 3D printing of denture base with the addition of ZrO2 NPs on denture adaptation property and diametral compression strength.Methods: 60 samples were printed, 30 disks for diametral compressive test and 30 denture base for denture adaptation test. Three groups per test (n=10). The control group for each test included unreinforced 3Dprinted denture base resin, and the other groups were reinforced with (2&
... Show MoreObjective(s): The aim of this study is to compare the impact strength of a heat cured denture-base acrylic resin
reinforced with metal wire and glass fibers.
Methodology: Forty five specimens were prepared from pink heat cure acrylic resin. Specimens were grouped into;
group-I (control group) which consists of 15 specimens with no reinforcement, group-II which consists of 15 specimens
reinforced with metal wire, and group-III consists of 15 specimens reinforced with glass fibers. Specimens were tested
by using charpy impact machine.
Results: The result showed that there was a highly significant difference in impact strength value among the testing
groups at (P < 0.001).
Conclusion: The impact str
... Show MoreObjective: One of the most important practical deficiencies of present denture base materials is fracture, therefore many
attempts have been made to reinforce of the repaired denture base resin. A desirable objective for this service is to obtain
optimum strength for repairs, which can be achieved by making available a good bond between original and repaired
materials.
Methodology: The present study was carried out to evaluate and compare the transverse strength of acrylic specimens
repaired by two different materials (hot-cure and cold-cure acrylic resin). A total of 50 specimens were prepared by hot
(40) repair: (10) by hot with retention bead, (10) by cold with retention bead and (10) repair by hot only, (10) repair
Background: Denture cleansing was an important step that could prevent the spread of infection and improve a patient's health, the durability of the dentures, and the overall quality of life; therefore, it was necessary to choose a suitable cleanser that, in addition to being effective, did not have an unfavorable effect on the qualities of the denture base resin itself when used for an extended period. For this purpose, this study aimed to evaluate the effect of tea tree oil (TTO) on Candida albicans adhesion and the surface roughness property of poly(methyl methacrylate) denture material after immersion in TTO. Methods: A total of 55 heat-cured acrylic resin specimens were used for C. albicans adherence and surface roughness tests. The
... Show MoreBackground: Polymer surfaces usually present problems in bonding and finishing due to their low hydrophilicity. The aim of this study is to investigate the effect of plasma treatment with the use of two types of gases (oxygen and argon) on surface roughness, and chemical surface properties of acrylic resin denture base polymer material. Materials and Methods: Three heat cured acrylic resin specimens of (2*8*30 mm) dimensions were prepared for each test carried out in this study. Two tests were conducted, surface roughness test and chemical surface analysis test. Results: Application of plasma treatment increased surface roughness for both oxygen and argon plasma treated acrylic resin specimen groups compared with control untreated group,
... Show MoreBackground: Poly (methylmethacrylate) is not ideal in every aspect and has disadvantages such as insufficient surface hardness, increase water sorption and poor impact resistance and the latter being the primary cause of fracture of denture base resins. The aim of this study was to evaluate the effect of addition of silanized nano- hydroxyapatite (HA) on some properties of heat cured acrylic denture base material. Materials and methods: HA nano particles were first silanized with ï§MPS (tri methacryloxypropyletrimethoxy silane coupling agent) then ultrasonicated with methylmethacrylate (monomer) to disperse agglomerated nano particles and mixed with polymer. 2% by wt of HA nano particles was selected as the best concentration that add
... Show MoreObjective: the aim of this study is to invest age and determine the effect of using (2) packing
technique (conventional and new tension technique) on hardness of (2) types of heat cure acrylic
resin which are (Ivoclar and Qual dental type).
Methodology : this study was intended the using of two types of heat cure acrylic (IVoclar and
Qual dental type) which are used in construction of complete denture which packed in two different
packing technique (conventional and new tension technique) and accomplished by using a total of
(40) specimens in diameter of ( 2mm thickness, 2 cm length and 1 cm width) . This specimens were
sectioned and subdivide into (4) group each (10) specimens for one group , then signed as (A, Al B
Objectives. This study aimed at finding out whether anterior teeth angulation and inclination have a relationship with the maxillary teeth and dental arch dimensions. Methods. Fifty study models with normal occlusion were selected from the archive of the Department of Orthodontics at Baghdad Dental Faculty. Maxillary dental arch width and length at different points were determined in addition to measuring anterior teeth angulation, inclination, crown thickness, overjet, overbite, and Bolton’s ratios. The unpaired t-test and Pearson’s correlation coefficient test were used for data analysis. Results. No statistical gender differences were reported in all measurements except the dental arch widths and length where males had signif
... Show MoreScleral acrylic resin is widely used to synthesize ocular prosthesis. However, the properties of this material change over time, thus requiring the prosthesis to be refabricated. Many studies were conducted to improve these properties by reinforcing this material with nanoparticles. This study aims to evaluate the effect of silver nanoparticle powder on the mechanical properties (transverse flexural strength, impact strength, shear bond strength, surface microhardness, and surface roughness) of scleral acrylic resin used for ocular prostheses. Two concentrations were selected from the pilot study and evaluated for their effects on scleral acrylic resin properties. According to the pilot study, 0.01 and 0.02wt% AgNPs powder improved
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