Conventional Acrylic Denture Research Articles

A study of role of flexible dentures in prosthodontics, partial edentulism, smile and esthetics

Replacing missing teeth is vital and mandatory for various daily functions of mouth. Conventional acrylic dentures have been used but now flexible dentures are the latest trends. This study is done to evaluate knowledge and awareness of flexible dentures in dental professionals. A questionnaire method was used to evaluate dental professionals' knowledge and awareness of flexible dentures in patients. Few dentists showed positive response and major were not aware of it. Few knew of advantages, disadvantages, uses and materials. More research should be done in this field so as to utilize this recent option at the maximum for benefit of patients clinically.

Evaluation and comparison of patient satisfaction with VertexThermosens and conventional acrylic complete dentures.

Patient perception and satisfaction with dentures are important indicators in prosthodontic treatment. This study aimed to compare patients' satisfaction with VertexThermosens dentures versus conventional acrylic dentures during a 12-month study period. This randomized study involved 60 participants aged between 45 and 80 with representation of both sexes. The patients were divided intotwo groups: The first group (experimental group), which had complete dentures from VertexThermosens base material included 30 participants. The second group (control group), which had complete dentures from convectional rigid acrylic base material, included 30 participants. Patient satisfaction with the dentures was assessed in each of the two Vertex/Acrylic groups through a specially created questionnaire of five questions with a five-point Likert scale of possible answers (0 = never; 1 = rarely; 2 = occasionally; 3 = often; and 4 = very often). After 12 months, intergroup comparison with Mann-Whitney U Test related to Q2 (p = 0.193), Q3 (p = 0.960), Q4 (p = 0.317), Q5 (p = 1.000) patient satisfactions indicated that there was no significant difference between the two groups (Vertex/Acrylic), except Q1 (p = 0.010) question, Vertex group was more satisfied. The results regarding the patients of both groups (Vertex/Acrylic) showed that after 12 months of wearing the denture, the satisfaction level regarding to all questions increased, except Q5-question for Vertex group, where the difference was not significant due to the already achieved maximum satisfaction at zero time. Based on the findings of this clinical study, it can be concluded that higher satisfaction is seen in patients rehabilitated with VertexThermosens dentures than with conventional rigid acrylic dentures.

Altered cast impression technique in the fabrication of metal frame partial dentures with distal extension: A case report

Metal frame denture is a more ideal treatment than the conventional acrylic denture for its narrower, thinner, rigid, and harder material, so that the design can be made ideally. The aim of this case report is to demonstrate the treat-ment of an edentulous case using altered cast technique to improve support for a partial denture with distal exten-tension. A 48-year-old female patient came to the Halima Dg.Sikati Makassar with complaints of chewing difficulty and lacking of confidence due to the loss of all her maxillary teeth and part of her mandibular teeth. The patient had never worn any denture and had no history of systemic disease. The patient wanted to have a denture made to resto-re the appearance and mastication. Then a panoramic x-ray was performed on the patient. Radiological images ap-pear to be missing all teeth in the maxilla, available teeth: 33, 32, 31, 41, 42 and 43, no impacted teeth, no foreign bodies, no inflammation or neoplastic tissue, good bone density, residual the roots of teeth 15 and 28. The pre-pros-thetic treatment plan was carried out by scaling and extracting the remaining roots on teeth 15 and 28. The prostho-thodontic treatment plan was the manufacture of partial metal frame dentures using the altered case molding techni-que. Altered cast is a molding technique used in the saddle free end of removable partial dentures. This impression technique can produce master case with maximum tissue support, within the limits of physiological tolerance and can accurately record the relationship between the tooth and the residual ridge. It is concluded that metal frame par-tial denture with Alter cast impression technique provides better and stable denture.

Comparative study of candida albicans adherence to conventional acrylic denture base materials and injection molding acrylic materials and poly ether ether ketone

Comparative study of candida albicans adherence to conventional acrylic denture base materials and injection molding acrylic materials and poly ether ether ketone

Perception and attitudes of dentists regarding the complications of conventional acrylic dentures and overdentures supported by teeth or implants.

This study aimed to assess the perception of dentists on the complications associated with prosthodontic treatments with acrylic dentures and overdentures in partially or complete edentulous patients. The study analyzed the complications of acrylic dentures and overdentures using a questionnaire with 24 open or closed questions, with single or multiple answers. The participants were 63 dentists, mostly women (77.8%), aged between 30 and 39 years old (52.4%), more than half of them with a clinical experience of less than 15 years. The main complications encountered were: lesions of the oral mucosa (52.4%), lack of maintenance (44.4%) or stability of dentures (39.7%), fracture of acrylic bases (14.3%), and detachment of attachment systems (44.4%). The complete maxillary acrylic dentures fractured most often (38.1%), frequently on the midline (58.7%), the main causes being accidental fall, masticatory stress, or lack of stability of the dentures. The most common intervention to correct the complications of dentures was the repair of fractured acrylic bases (33.3%). The study exposed that dentists are aware of the possible complications of acrylic dentures, which they correlate with the peculiarities of oral structures, but also with some deficiencies of prosthodontic restorations, materials and technologies. Maxillary acrylic dentures, overdentures, and partial acrylic dentures have a high risk and fracture rate, but the use of new technologies and materials can reduce the complications rate of acrylic dentures and overdentures.

Analysis of Denture Base Displacement between Conventional Acrylic Removable Partial Dentures and Click Fit Partials for Kennedy\'s Class I and II Situations: An In Vitro Study

The aim of this study was to evaluate the displacement of the denture base of conventional acrylic dentures and Click Fit partials in Kennedy's class I and II situations in the mandibular arch. Four removable partial dentures-two conventional clasp dentures and two attachment dentures (Click Fit)-were designed. The two conventional clasp dentures were retained by C (conventional) clasps, and the two attachment dentures were retained by rigid precision attachments. The displacement of denture bases and the movements of denture bases were investigated, and the influences of denture design were studied. The values obtained were statistically analyzed by using independent t-tests. For all statistical purposes, a p-value of ≤0.001 was considered significant. The results showed that mean vertical displacements (mm) of the conventional acrylic removable partial denture base for Kennedy's class I mandibular arch under 50, 75, and 100 N forces were 0.0317, 0.04377, and 0.06392, respectively, and those for Kennedy's class II mandibular arch under 50, 75, and 100 N forces were 0.04922, 0.09849, and 0.1522, respectively. Vertical displacements (mm) of the Click Fit removable partial denture base for Kennedy's class I mandibular arch under 50, 75, and 100 N forces were 0.02185, 0.03436, and 0.005365, respectively, and those for Kennedy's class II mandibular arch under 50N, 75N, and 100N forces were 0.0445, 0.07851, and 0.14457, respectively. The difference between the groups was statistically significant (p ≤0.001). The vertical displacement of the denture base retained by conventional C clasps was more than that of the denture base retained by rigid precision attachment. The displacement of the denture base tended to be less when the denture was designed with a rigid connection for the retainer and with cross-arch stabilization as in Kennedy's class I case. This research evaluated the vertical denture base displacement using different designs and retention types. Hence, it helped predict the prognosis of different removable partial denture base designs in various clinical conditions.

Evaluation of bond strength between nanohybrid composite teeth and two different denture base materials (comparison study )

Purpose: aim of the study was to compare the bond strength of nanohybrid composite artificial teeth (NHC) and two types of denture base material ( acrylic denture base material and thermoplastic monomer free semi-rigid micro crystalline polymer denture base material (Karadent) . Material and Methods : nanohybrid composite teeth (premolars) was sliced equally , grooved for increasing contact surface and attached to 16 discs of denture base material (8 for each group), then the discs where grouped into two groups . The samples were subjected to tensile forces till failure by using the Instron Universal testing machine. Results : bonded nanohybrid composite teeth (NHC) to conventional acrylic denture base disc specimens showed better results in comparison to thermoplastic monomer free semi-rigid micro crystalline polymer denture base materials ones. Conclusion : it is recommended to use NHC teeth more often with conventional acrylic denture bases than thermoplastic monomer free semi-rigid micro crystalline polymer denture base materials.

THE DEVELOPMENT OF FLEXIBLE DENTURE MATERIALS AND CONCEPT: A NARRATIVE REVIEW

Introduction: Flexible denture is an alternative treatment modality for removable partial denture (RPD) that aid the retention by ensuring seal around the entire border of the denture. It is also referred as hypoallergenic denture especially for those who are allergic towards conventional acrylic denture which is the poly-methylmethacrylate monomer (PMMA) and metal (cobalt chromium). The flexible material exhibits lower flexural modulus than conventional type of baseplate material denture that makes it nearly unbreakable. Nowadays, there are a handful of different flexible materials in the dental market for the general dental practitioners to choose but somehow the studies on the properties of these different types of flexible materials are sparse. Objectives: The present study is to study the development of the flexible materials, the different type of flexible materials and their physical properties. Methods: From the limited article journals available, the authors have summarized the history, development and constituents of different type of flexible materials used in fabricating denture. Besides that, the authors also discussed about the indications, contraindications, advantages and disadvantages of the materials in denture constructions based on all the published researches available on this topic using published materials available in the dental library, University of Malaya and the databases (Science Direct, PubMed). Conclusion: Each flexible material has its pros and cons. Therefore, careful selection of material and understanding of the flexible dentures’ indications and contraindications are utmost importance to make sure the best treatment outcome. Hence, patients’ best interest and quality of life can be upheld.

Wear Resistance of 3D Printed and Prefabricated Denture Teeth Opposing Zirconia.

To evaluate the wear resistance of a recently developed three-dimensional (3D) printed denture teeth resin compared to three commercially available prefabricated denture teeth. A total of 88 maxillary first molar denture teeth were evaluated: C (Classic; Dentsply Sirona, York, PA), DCL (SR Postaris DCL; Ivoclar Vivadent, Schaan, Liechtenstein), IPN (Portrait IPN; Dentsply Sirona, York, PA), and F (Denture Teeth A2 Resin 1 L; Formlabs, Somerville, MA). The 3D printed denture tooth specimens were fabricated from a methacrylate-based photopolymerizing resin using stereolithography (SLA). Denture teeth were subjected to a three-body wear test with a poly(methylmethacrylate) (PMMA) abrasive slurry. A Leinfelder-style four station wear apparatus with custom bullet-shaped milled zirconia styli was utilized with a load force of 36-40 N at 1.7 Hz for 200,000 cycles. Maximum depth of wear was measured using a lab grade scanner and analyzing software program. Data were analyzed using a one-way ANOVA followed by the Tukey's Multiple Comparisons post hoc test (α = 0.05). A statistically significant difference in depth of wear was found between denture tooth materials (p < 0.001). The mean vertical depth of wear for the 3D printed denture teeth (0.016 ± 0.010 mm) was statistically significantly less than the prefabricated denture teeth. The highly cross-linked denture teeth, DCL (0.036 ± 0.011 mm) and IPN (0.035 ± 0.014 mm), exhibited statistically significantly less wear than the conventional acrylic denture teeth. The conventional acrylic denture teeth demonstrated the greatest wear (0.058 ± 0.014 mm). No significant difference in depth of wear was found between DCL and IPN (p > 0.001). Denture tooth material significantly influences the depth of wear. The 3D printed denture teeth demonstrated superior wear resistance compared to the commercially available prefabricated denture teeth when opposed to zirconia. Denture teeth fabricated with SLA technology may have a promising future in prosthetic dentistry.

Tensile bond strength of acrylic and composite denture teeth to milled CAD/CAM resins

Objective: was to evaluate effect of different surface treatment on tensile bond strength of two different types of artificial teeth to CAD/CAM denture base. Materials and Methods: 160 specimens were fabricated and divided into two main groups according to the denture base material. Group (A) for conventional denture base (HCAR denture base) and Group (B) for CAD/CAM denture base. According to the artificial teeth each group of denture base was subdivided into two subgroups, subgroup (I) for conventional acrylic denture teeth and subgroup (II) for composite resin denture teeth. According to the surface treatment each subgroup of artificial teeth were subdivided into four subgroups as following: Subgroup 1: no surface treatment (control group). Subgroup 2: sandblasting with 250 micron alumina particles. Subgroup 3: roughening with diamond bur. Subgroup 4: specimens were treated by dichloromethane. Results: The results showed that Pre-polymerized CADCAM acrylic resin denture bases specimens exhibited non-significant lower bond strength than HCAR denture base specimens (p>0.05), acrylic resin denture teeth demonstrated higher bond strength to denture bases than composite resin denture teeth (p≤0.05). Conclusion: the Pre-polymerized CADCAM acrylic resin denture bases specimens exhibited non-significant lower bond strength than HCAR denture base specimens, and acrylic resin denture teeth demonstrated higher bond strength to denture bases than composite resin denture teeth, the bond strength of the denture teeth treated with both dichloromethane and sandblasting was improved while the bond strength of the denture teeth treated by roughening with diamond bur was decreased.

A study to compare adhered oral flora to soft liner and conventional denture base surface in complete denture patients

Background: Denture base materials are subjected to sorption, a process of absorption and adsorption of liquids depending on the environmental conditions, also their fitting surface is subjected to microbial adhesion due to surface irregularities. Soft silicon liners are usually used with removable appliances to decrease load concentration on the hard and soft tissues. Silicon liners also undergo fluid sorption and microbial adhesion.Aim: This study was carried out to assess the effect of standardizing the oral hygiene conditions on the microbial load difference between conventional acrylic denture bases and silicon soft relining material (Mucopren soft) used to reline mandibular complete dentures in atrophied mandibles. Methods: Conventional complete dentures were constructed for 25 patients with flat atrophic mandibular ridges to be used for two weeks, salivary swabs were collected to evaluate oral flora attached on the fitting surface of the denture base and the buccal vestibule, soft liner was applied for all patients mandibular denture surfaces and the same approach was repeated after two weeks of the liner use. Results: Microbial load was found to be significantly higher in the fitting surfaces of the silicon soft liner, than in the conventional acrylic base fitting surfaces.Conclusion: Even under controlled oral conditions, Mucopren soft silicon liner incorporates greater microbial load than acrylic material thus, subjecting patients to numerous infections.

Relative Impact of Oral Rehabilitation on Quality of Life and Patient Satisfaction Following Mandibular Resection in a Sub-Urban Nigerian Tertiary Hospital

Background: Resection of the mandible can lead to bony defect which has a direct bearing on the quality of life of the patient. Reconstruction of such defect is necessary to restore aesthetics but optimal functioning of the oral cavity can only be achieved with prosthodontic rehabilitation. We, hereby, report the impact of oral rehabilitation on patients’ satisfaction and quality of life after mandibular reconstruction in our institution. Materials and Method: Patients who had oral rehabilitation following mandibular reconstruction from January 2010 to December 2015 were included. Patients’ oral health related quality of life [OHRQL] before and after rehabilitation was evaluated using the head and neck module of the European Organization for Research and Treatment of Cancer [EORTC]. Oral functions and denture satisfaction were also evaluated with Visual Analogue Scale [VAS]. Data obtained were analyzed with SPSS version 20 and level of significance was set at p < 0.05. Result: Of the 43 patients who had mandibular reconstruction during the study period, only 21 [48.8%] had dental rehabilitation. Twelve patients [57.1%] had conventional acrylic denture, 5 had fixed denture [bridge] while 4 patients had rehabilitation with dental implants. The mean follow-up period after rehabilitation was 8.42 months [Range: 6 - 22 months]. Although, OHRQL analysis revealed an improvement following rehabilitation, only the social aspect of the evaluation was statistically significant [p < 0.01]. Also, type of rehabilitation had a significant correlation with oral function as patients who received dental implant had better VAS score [p = 0.00]. On the contrary, there was no statistically significant difference in aesthetics amongst the patients regardless of type of rehabilitation [p = 0.26]. Conclusion: Findings from this study showed that there is improvement in OHRQL following dental rehabilitation. Also, Patients who were rehabilitated with dental implant had better oral function than those with fixed or conventional denture.

The Comparison of Retention between Hot Curing and Fluid Denture Base Acrylic Resin (In Vivo)

Background and objectives: Adequate retention is a basic requirement for the acceptance of complete denture. The aim of this study was to evaluate the retention quality of fluid denture base materials and compare it with conventional acrylic denture base materialsMethod: Sixteen edentulous male patients with an age 45-60 years participated in the study. For each patient two denture bases were constructed, one of them made from fluid denture base materials and the other made from hot acrylic denture base materials. A specially designed strain gauge measuring device was used to measure the force required to dislodge the two dentures from basal seats. Six measurements of retention of newly inserted denture base were recorded for each patient (three for maxillary acrylic denture base and three for maxillary fluid denture base).Results: The results of the retention test showed that the fluid denture base materials required more force in order to dislodge denture than the heat cure denture base materials, which means a significant improvement in retention quality obtained by fluid denture base materials. Conclusions: It has appeared that the fluid acrylic denture base materials produce denture base material with excellent retentive efficiency to the underlying tissue when compared to conventional denture base materials.

Wear resistance of nano silica modified acrylic denture teeth and nano filled composite denture teeth

Artificial denture teeth are subjected to wear from daily masticatory functions. This wearaffects the denture esthetics, functions and in turn results in patient discomfort. The purpose ofthis study was to evaluate the wear resistance of nano composite fabricated artificial denture teethand conventional acrylic denture teeth reinforced with silica nano particles. A total number of60 samples were used. Samples were divided into equal four groups (n=15). The first group wasfabricated from nano filled composite. The second and third groups were silica nanoparticlesmodified acrylic denture teeth with two different concentrations 0.1% and 10% respectively. Thefourth group was conventional acrylic resin denture teeth and served as a control. The 2-bodywear testing was performed with a multi-modal ROBOTA chewing simulator. Wear was thenevaluated by the means of weight loss and surface roughness. The nano-composite group recordedsignificantly higher wear resistance than conventional and silica modified acrylic resin groups. Thesilica modified acrylic resin group with 0.1% concentration recorded a lower surface roughnessthan any of the other groups. In conclusion; Nano-composite teeth can be used as artificial dentureteeth exhibiting significant higher wear resistance than conventional and silica modified artificialacrylic teeth.

Bite Force Evaluation in Complete Denture Wearer with Different Denture Base Materials: A Randomized Controlled Clinical Trial.

Aim:The aim of this study is to evaluate the maximum bite force (MBF) with different denture base materials in completely edentulous patients.Materials and Methods:MBF was evaluated in randomly selected 100 completely edentulous patients. Patients were selected from the Outpatient Clinic, College of Dentistry, Aljouf University, Saudi Arabia. The patients were randomly divided into two equal groups: Group I (control group): Patient received a conventional heat-cured acrylic complete denture (Vertex™ Regular, Vertex-Dental B.V., The Netherlands) and Group II (experimental group): Patient received a thermoplastic complete denture (Vertex™ ThermoSens, Vertex-Dental B.V., The Netherlands). MBF measurements were taken at the time of new denture placement and after 6 months of denture use. Statistics were analyzed using independent t-test to compare the MBF measurements between both groups.Results:At the time of denture placement, there was no significant difference in bite force measurements between both groups. Bite force is increasing considerably after 6 months of denture use, and it was higher than MBF recorded at the time of new prosthesis placement in the same group. The MBF values were considerably higher in patients with a thermoplastic denture than patients with conventional acrylic denture with statistically significant difference after 6 months of denture use.Conclusion:After 6 months of denture use, patients with a thermoplastic denture have a higher biting force than patients with a conventional acrylic denture. Therefore, it could be considered a treatment plan option according to the ridge nature and quality to solve the problem of diminished bite force in old age patients.

STRESS ANALYSIS OF TWO DIFFERENT ATTACHMENTS FOR A TWO IMPLANT RETAINED MANDIBULAR OVERDENTURE

Background: Implant overdenture retained by two implants installed in the interforaminal area of the completely edentulous mandible has become the standard of care for completely edentulous patients. Various attachments have been used to retain a mandibular implant retained over denture, the ball attachment has been the most commonly used un-splinted attachment to retain a mandibular overdenture owing to its low cost and simplicity. A newly introduced attachment made from polyetherketoneketone (PEKK) which have reported to have high chemical and mechanical resistance to wear and high tensile, fatigue and flexural strengths. The aim of this in vitro study is to analyze the distribution of stresses around the two installed implants in the inter-foraminal area of a completely edentulous mandible using strain gauges utilizing an implant retained overdenture with two different types of attachments one with a nylon cap and the other with a PEKK cap.Materials and Methods: A clear heat cured acrylic completely edentulous mandibular model has been used in this in vitro study to fabricate a lower conventional acrylic denture following conventional steps. In the canine region bilaterally two dummy implants were installed and attached to the model using self-cure acrylic resin. The acrylic resin was prepared around each implant into a box shape with a thickness of 1mm into four surfaces; buccal, lingual, mesial and distal. Strain gauges of length 5mm, resistance of 120.4±0.4 Ω and a gauge factor of 2.09 ± 1 %, were attached to each surface. The same lower acrylic denture was used for pickup of the two attachments; the ball and CMLOC attachment. The implant retained overdenture retained by the each attachments was subjected to unilateral and bilateral vertical static load of 100N using a universal testing machine. The wires of the strain gauges were connected to the strain meter to record the micro-strain using a special software, 10 readings were recorded for each attachment. Results: when the implant retained overdenture have been subjected to unilateral loading, the loading side have recorded a higher statistically significant mean micro-strain than the unloaded side retained by both attachments, The overdenture retained with ball attachment have shown a significant increase in micro-strain on the loaded side than that with the CM LOC attachment, while for the unloaded side the overdenture retained with CMLOC attachment induced more micro strain than the ball attachment. While during bilateral loading, a statistically significant higher mean micro strain was recorded in the left implant than the right implant, and the CM lOC have shown a higher statistically significant mean micro strain than the ball attachment for the left implant , while the ball attachment have shown a statistically significant increase in micro strain for the right implant. Conclusion: The newly introduced attachment the CM LOC tends to show a better performance with regards to the micro-strains induced around the implants and also regarding improving the stability of the denture, On the other hand the ball attachments despite having induced more micro-strain around the implants, it could have a higher retention than the CM LOC attachment. Further studies comparing the retention of the new attachment CM LOC and the ball attachment has to be carried out to confirm the conclusion of the present study.

Evaluation of Retention for Implant RetainedMandibular over Denture using Two Different Denture Base Materials

Objectives: This study was made for measuring and comparing the Retention of implant retained mandibular overdenture using resilient attachment with two different denture base materials (flexible and conventional acrylic resins). Methods/ Statistical Analysis: Twenty male patients selected for this study with completely edentulous mandible and divided according to the type of denture base material used into two equal groups, both groups received implant retained overdenture with resilient attachment. Group I; denture base made from conventional acrylic, Group II; denture base from thermo-elastic flexible acrylic, retention evaluation was made zero time, two months and four months after insertion. Findings: In this study, there was no statistical significance of difference between the groups, at time of insertion, 2 and 4 months after insertion. The highest values of retention were enlisted with the overdenture made from them oplastic acrylic resin and that may due to high inter facial surface tension recorded values of thermoplastic acrylic resin. Strong tension increase retention of the prosthesis in place. Flexible acrylic denture base showed better retention values and function than denture base made from heat cured acrylic resin material and it is agreed with another study which proved that retention values of Thermo-elastic resin was higher than conventional resin as the Thermo-elastic resins have greater flexibility, adaptation and fitting values than conventional resin. So, it has an improved retention because of inter-facial surface tension effect. Application/Improvements: Using overdenture base made of thermo-elastic acrylic resin clinically better than using overdenture base made of conventional acrylic denture base in retention and function.

Spectrogram Analysis of Complete Dentures with Different Thickness and Palatal Rugae Materials on Speech Production

Objective. To investigate the influence of reproduction of different thickness and palatal rugae materials on complete dentures speech using Computerized Speech Lab (CSL) (spectrogram). Materials and Methods. Three completely edentulous male patients (aged 50–60 years) were selected for reading a paragraph. Twelve upper dentures were constructed, four for each patient. The patients' speech groups were divided into five groups, Group I: patients without dentures; Group II: patients rehabilitated with conventional acrylic dentures; Group III: patients with conventional acrylic dentures with rugae reproduction; Group IV: patients with dentures with metallic framework of minimal thickness and direct ragged metallic palatal surface at rugae area; Group V: patients with dentures with palatal rugae constructed from resilient acrylic resin material with thickness less than conventional denture. Speech samples were recorded after insertion of each denture for groups using Computerized Speech Lab (CSL) (spectrogram). The sounds selected were lingopalatal /s/z/sh/t/d/ and /l/. Results. Group III produced high mean significant difference with /sh/t/ sound. For Group IV, the difference was noticed with /s/z/sh/t/ and /d/ sounds, while for Group V the difference was shown with /z/l/ sound (P < 0.05). Conclusion. It is recommended to reproduce the rugae area in complete denture because the phonetic quality of complete denture with rugae is superior to the conventional denture.

Effects of various denture cleansers on surface roughness of hard permanent reline resins.

The aim of this study was to investigate the influence of denture cleansers on surface roughness (Ra, µm) of two hard permanent reline resins and a conventional acrylic denture base resin. Fifty specimens of each material, measuring 10 mm×2 mm were randomly divided into 1 control and 4 experimental subgroups (n=10). Surface roughness values were measured using profilometer before and after immersion in distilled water and in 4 different denture cleansers for 8 h for 140 days. The Kruskal Wallis and Wilcoxon Signed Ranks tests were used for comparison among groups with a significance level of α=0.05. Immersion in denture cleansers significantly increased the surface roughness of reline resins and the difference among the cleansers was statistically significant (p=0.059). Denture cleansers can cause significant surface roughness alterations on hard permanent reline resins and denture base resin where their effect may differ according to the selected resin material.

Effect of immersion cleansers on the bond strength between a denture base resin and acrylic resin teeth

The aim of the present study was to assess the shear bond strength between a heat-polymerized denture base resin and acrylic resin teeth after immersion in different denture cleansers by simulating a 180-day use. Two acrylic teeth (Biotone, Biotone IPN, Dentsply Ind. e Com., Rio de Janeiro, RJ, Brazil) were chosen for bonding to a heat-polymerized denture base resin (Lucitone 550- Dentsply Ind. e Com., Rio de Janeiro, RJ, Brazil). Eighty specimens were produced and divided into eight groups (n=10) according to their experimental condition (distilled water, 2% chlorhexidine digluconate, 1% sodium hypochlorite and Corega Tabs). Shear bond strength tests (MPa) were performed with a universal testing machine at a crosshead speed of 0.5mm/min. Data were analyzed by two-way analysis of variance (ANOVA) and Student-Newman–Keuls' multiple comparisons post hoc analysis (α=.05). The shear bond strength results revealed statistically significant differences between the groups. For the Biotone IPN tooth, significantly lower shear bond strength values were found for the group immersed in sodium-perborate solution (4.48±2.18MPa) than for the group immersed in distilled water (control group) (10.83±1.84MPa). For Biotone, significantly higher bond strength values (10.04±3.28MPa) were found for the group immersed in Corega Tabs than for the control group (5.45±2.93MPa). The immersion in denture cleanser solutions was more detrimental to the conventional acrylic denture tooth (Biotone) than to the highly cross-linked denture tooth (Biotone IPN). However, this effect was not observed for the groups immersed in Corega Tabs solution, regardless of the type of denture tooth.