Effect of flask closure method and post‐pressing time on the upper denture base adaptation

doi:10.1111/j.1741‐2358.2009.00307.x
Effect of flask closure method and post‐pressing time on the upper denture base adaptation Objectives: The purpose of this study was to evaluate the effect of flask‐closure methods, post‐pressing times and acrylic resins on denture base adaptation. Materials and methods: The resins were flasked using a hydraulic press and closed with the traditional clamp or RS system. Conventional heat‐cure resin was polymerised immediately or at 6 h post‐pressing at 74°C for 9 h. Rapid cycle heat‐cure resin was polymerised in boiling water for 20 min. After cooling, the bases were deflasked and the sets of cast‐base transversally sectioned in the regions distal to the canine, mesial to the first molar and in the posterior palatal zone. The adaptation was measured with an optical microscope (0.0005 mm) at five reference points for each section. Data were analysed using anova and Tukey’s test (α = 0.05). Results: Traditional clamp and immediate post‐pressing time improved base adaptation for conventional heat‐cure resin. Both post‐pressing times showed most accurate base adaptation for conventional heat‐cure resin when the traditional clamp was used. Immediate post‐pressing time improved base adaptation for conventional heat‐cure resin and the 6‐h delay in time was significant for the rapid cycle heat‐cure resin. Conclusions: Traditional clamp and immediate post‐pressing time improved base adaptation for conventional heat‐cure resin.     

Influence of different metal flask systems on tooth displacement in complete upper dentures

doi: 10.1111/j.1741‐2358.2010.00392.x Influence of different metal flask systems on tooth displacement in complete upper dentures Objective: To verify the occurrence of tooth displacement in dentures processed by moist hot‐polymerisation using traditional and experimental metal flask systems. Materials and methods: Waxed complete dentures were randomly assigned to three groups (n = 10), including traditional (TF) and experimental flasks (DF and HHF). Metal pins were placed at the incisal edge of maxillary central incisors (I), buccal cusp of first premolars (P) and mesiobuccal cusp of second molars (M). Transversal (I–I, P–P and M–M) and anteroposterior (LI–LM and RI–RM) distances were measured before and after denture processing using an optical microscope. The dentures were processed by hot water curing cycle (9 h/74°C). Collected data were analysed by anova , Paired Student’s t‐test and Holm–Sidak method (p < 0.05). Results: All measured distances demonstrated contraction after polymerisation, except for LI–LM in TF and RI–RM in DF and HHF. Statistically significant differences were found between the distances P–P for DF and HHF, and M–M for all groups. Comparison among flask systems revealed statistically significant difference in the P–P distance for the TF and HHF. Conclusion: Different flask systems did not cause variation in tooth displacement during denture processing, with the exception of P–P distances for the TF and HHF. There is no evidence that different metal flask systems would promote tooth displacement of clinical significance.     

Effect of different repair techniques on the accuracy of repositioning the fractured denture base

Objective: This study investigated the efficacy of different techniques for the union of fragments of a denture before repair and on the accuracy of the reposition. Materials and methods: For this study, 20 maxillary dentures made with Lucitone 550 heat‐cured resin were used. Points were determined with a scanner on the cusp of the teeth, as a measurement of the segments. After digitisation, each model was exported to the AUTOCAD R 14 program and two‐dimensional measurements of the distances between the marked points were made. After the initial analysis, the dentures were fractured into two segments using an impact test machine. For the repair, maxillary dentures were divided into two groups; in the first, the repair was carried out using Kerr’s sticky wax and in the second group, Super Bonder was used to join the fragments, with subsequent inclusion of DENTSPLY^® Repair Material resin. After the repair, the points of the maxillary dentures were measured again. The numerical values obtained were tabulated to compare the measurements before fracture and after the repair. For statistical analysis, analysis of variance was employed, using a single factor and double factor, followed by the Tukey test with a reliability of 95%. Results: The results demonstrated a statistically significant difference between the materials used to join the dentures for repair, where the dentures were joined with sticky wax presented a larger variation in the distances between the points. Conclusion: The variation in distances between the points is influenced by the agent of repair.     

In vivo assessment of the effect of an adhesive for complete dentures on colonisation of Candida species

doi: 10.1111/j.1741‐2358.2009.00345.x
In vivo assessment of the effect of an adhesive for complete dentures on colonisation of Candida species Objective: Denture adhesives have long been recognised by denture wearers as a useful adjunct to denture retention and stability. The objective of the present study was to evaluate, in vivo, the effect of a denture adhesive on oral quantities of Candida species by determination of absolute counts of colony‐forming units (CFU) per ml of saliva of individuals who use this denture adhesive for a period of 14 days. Materials and methods: Twenty‐four individuals were randomised in two equal groups of 12 (test and control), with the individuals of the test group using the adhesive for 14 days. Samples of saliva were collected from all individuals on days 0 (initial), 7 and 14. Aliquots of saliva were diluted and plated in duplicate on Sabouraud dextrose agar with chloramphenicol and incubated for 37°C for 48 h, the CFU/ml were counted in the individuals of each group and the data of each group were compared at the different time periods and analysed statistically by the non‐parametric Mann‐Whitney U‐test (α ≤ 5%). Results: There were no statistically significant differences between the test and control groups during the test periods. Conclusion: Within of the limitations of this study, the data suggested that the denture adhesive tested did not significantly alter the oral microbiota during the 14‐day trial period.     

In vitro and clinical evaluation of specific dentifrices for complete denture hygiene

Objectives: To study the physical properties of two experimental dentifrices for complete denture hygiene, their effect on denture biofilm removal and antimicrobial properties by means of a clinical trial. Materials and methods: The experimental dentifrices comprised two compositions. One was based on the addition of 1% chloramine T (D1) and the other on the presence of 0.01% fluorosurfactant (D2). Measurements of density, pH, consistency, rheological features and abrasiveness were conducted. Sixty complete denture wearers were randomly assigned to three groups and were instructed to brush their dentures with a specific toothbrush: (1) Water (control); (2) D1; or (3) D2. Each method was used for 21 days. Denture biofilm was disclosed by a 1% neutral red solution and quantified by means of digital photos taken from the internal surface. Microbiological assessment was conducted to quantify Candida sp. and mutans streptococci. Data were evaluated by one‐way anova and Tukey HSD, or Kruskal–Wallis (α = 0.05). Results: Both dentifrices decreased biofilm coverage when compared with the control group. D1 was the most efficacious treatment to reduce mutans streptococci, whereas D2 showed an intermediate outcome (anova , p < 0.040). No treatment influenced Candida albicans or non‐albicans species (Kruskal–Wallis, p = 0.163 and 0.746, respectively). Conclusion: It can be concluded that brushing complete dentures with the experimental dentifrices tested could be effective for the removal of denture biofilm.     

Elderly complete denture wearers: a social approach to tooth loss

doi: 10.1111/j.1741‐2358.2011.00550.x Elderly complete denture wearers: a social approach to tooth loss Objectives: To correlate emotional reactions to tooth loss with denture satisfaction attributes in elderly complete denture wearers. Background: Total tooth loss is a serious life event, and poor oral health has an impact on daily life. Edentulism treated by rehabilitation with dentures can have a positive effect on patients’ self‐image and social behaviour. Methods: A group of 80 edentulous subjects undergoing routine prosthetic care in a Greek Department of Prosthetic Dentistry were interviewed using two structured questionnaires. The first questionnaire explored reactions to tooth loss, whereas the second measured their subjective experience of complete dentures. The responses to both questionnaires were compared using the statistical package spss v.17. Results: The results showed significant correlation between aspects of tooth loss experience and complete denture satisfaction. Despite the fact that a substantial proportion of patients were satisfied with their complete dentures, some patients experienced increased social and psychological problems related to their edentulousness and the wearing of complete dentures. The aesthetic and functional aspects of complete dentures affected both patients’ social behaviour and self‐confidence. Conclusions: Total tooth loss was not only reflected in patient’s social behaviour and self‐image, but it had a complex and multifaceted impact on satisfaction from complete dentures.     

Clinical and microbiological efficacy of three different treatment methods in the management of denture stomatitis

Gerodontology 2010; doi: 10.1111/j.1741‐2358.2009.00354.x
Clinical and microbiological efficacy of three different treatment methods in the management of denture stomatitis Objective: This study evaluated. the effect of mouthrinses and tissue conditioner on the clinical findings and microbial flora of 60 patients with Newton’s type II denture stomatitis (N2DS) Background: Denture stomatitis is a common problem in complete denture wearers. Materials and methods: Sixty patients with N2DS were included in this study and divided into three groups. Two groups of patients were instructed to rinse their mouth with the designated mouthrinses DioxiDent and Corsodyl twice daily for 1 min and to soak their dentures overnight in these solutions for 15 days. For the third group, tissue conditioner was placed in each of 20 patients’ existing maxillary dentures. Patients were evaluated both clinically and microbiologically at baseline and after 15 days. Palatal swabs and smears were taken from each patient before and after treatment and these samples were examined mycologically. The difference between Candida colonisation before and after treatment and the differences between pre‐treatment and post‐treatment clinical findings were assessed. Results: DioxiDent and Corsodyl showed an improvement in palatal inflammation and a decrease in Candida colonisation compared to Visco‐gel. Conclusions: The effectiveness of topical chlorine dioxide and chlorhexidine gluconate in the management of N2DS was demonstrated.     

Comparative analysis of biofilm levels in complete upper and lower dentures after brushing associated with specific denture paste and neutral soap

Objectives: The objective of this study was to compare and correlate biofilm levels in complete upper and lower prosthesis after brushing, associated with specific paste and soap, by means of computerised methodology. Materials and methods: Forty‐five complete denture wearers were selected and instructed to brush their prostheses (Soft Oral B 40) three times a day for 3 weeks with water (Control), specific paste for complete dentures (Corega Brite) (Experiment 1) and neutral soap (Experiment 2). The study was based on a cross‐over model and a wash‐out period was not included. For biofilm quantification, the internal surfaces were dyed (neutral red 1%), photographed (Canon EOS Digital) and the disclosed biofilm was measured with the Image Tool 2.0 software. The products were assessed by means of a questionnaire regarding their hygiene properties and acceptance. Results: The variance analysis indicated that the lower prostheses exhibited a mean biofilm percentage, significantly higher than the upper prostheses and that brushing with paste (Experiment 1) was more effective than soap (Experiment 2) and, in turn, this was more effective than water (Control). There was a high biofilm correlation (Pearson correlation) between both prostheses. Both products were well accepted by the patients, but the most favoured one was the paste. Conclusions: This was effective in controlling the biofilm and can be used preventatively in the maintenance of oral health by wearers of complete dentures. This is important where the lower prosthesis can harbour microorganisms which may act as a reservoir for other areas of the mouth and thus enhance the importance of proper hygiene.     

Distribution of biofilm on internal and external surfaces of upper complete dentures: the effect of hygiene instruction

Objectives: The purpose of this study was to evaluate biofilm distribution over internal and external surfaces of upper complete dentures. It was also aimed at assessing the effect of oral hygiene instructions before and after home use of a disclosing solution. Materials and methods: The sample consisted of 29 complete denture wearers whose upper prostheses were evaluated. Surface biofilm was disclosed by means of a 1% neutral red solution and quantified with regard to internal and external surfaces. Oral hygiene information was provided on an individual basis. During the second stage, an amount of disclosing solution was given for domestic use. Results: Internal and external surfaces presented a similar amount of biofilm, which was concentrated over the area of the posterior teeth area, palatal rugae and the internal vestibular incline of the distobuccal flange. This pattern was maintained during the study. However, overall amounts were reduced following denture hygiene information. The use of disclosing solution by subjects at home resulted in a further reduction. Conclusions: It was concluded that biofilm deposits were similar over assessed surfaces, regardless of the type of procedure but irregular areas presented greater amounts. Oral health instruction was effective in reducing the biofilm, in particular when associated with home use of a disclosing agent.     

Examination of denture-cleaning methods based on the quantity of microorganisms adhering to a denture

doi: 10.1111/j.1741‐2358.2011.00461.x Examination of denture‐cleaning methods based on the quantity of microorganisms adhering to a denture Objectives: To investigate effective denture‐cleaning methods, we examined the relationships between the quantity of microorganisms adhering to dentures and the use of a denture brush and the frequency of use of a denture cleanser. Subjects and Methods: Denture plaque was collected from the mucosal surface of the examined dentures, which were 142 and 80 upper and lower complete dentures, respectively, worn by 96 outpatients (mean age: 71.9 years) of a university hospital and 41 nursing home residents (mean age: 84.8 years). The collected microorganisms were counted in terms of isolated representative colonies that were cultured and identified using standard methods. The use of a denture brush, the frequency of use, and the type and soaking time of denture cleansers as denture‐cleaning methods were surveyed. Results: The quantity of microorganisms was significantly lower in dentures of denture brush users than in those of non‐users in the outpatients (p < 0.01, Mann–Whitney U test). The quantity of microorganisms was significantly lower in the dentures of outpatients who used a denture cleanser daily or 3–4 times a week than in those who used one once or less per month and in the dentures of nursing home residents who used one daily than in those who used one at other frequencies (p < 0.05, Kruskal–Wallis test, followed by Dunn’s Multiple Comparison test). Conclusion: Within the limitations of this study, it was concluded that the use of a denture brush and daily use of denture cleanser should be recommended to complete dentures wearers as denture‐cleaning methods that effectively reduce the quantity of microorganisms adhering to dentures.     

Effects of home and office care denture reliners on maxillary complete dentures

doi:10.1111/j.1741‐2358.2009.00308.x
Effects of home and office care denture reliners on maxillary complete dentures Objectives: The aim of this study was to evaluate the effects of office (OR) and home (HR) care temporary denture reliners on satisfaction and functional outcomes in maxillary complete denture wearers. Methods: Thirty‐four maxillary edentulous patients received application of either OR or HR to their maxillary complete dentures. Patient’s ratings on satisfaction and functional aspects were measured on a 100‐mm visual analogue scale at 4 days post‐application. Associations between baseline ratings and improvement were also assessed. Results: There were no significant differences between the two groups in satisfaction ratings or in the functional outcomes. The OR group showed a significant improvement in mastication and retention, whereas the HR group exhibited a significant improvement in general satisfaction and mastication. Improvement was negatively associated with baseline ratings of speech, ease of cleaning, stability and retention in the OR groups and across all variables, except ease of cleaning, in the HR group. Conclusion: When used correctly, home care denture therapy can be as effective as office applied temporary liner in improving satisfaction with problematic maxillary dentures.     

Effect of double flasking and investing methods on artificial teeth movement in complete dentures processing

doi: 10.1111/j.1741‐2358.2011.00494.x
Effect of double flasking and investing methods on artificial teeth movement in complete dentures processing Purpose: The aim of this study was to evaluate linear dimensional alterations of artificial teeth for complete dentures when using different investment and flasking techniques. Background: Dimensional changes in the vertical dimension may occur owing to changes in artificial teeth positioning caused by different investing and flasking techniques. Materials and methods: Thirty pairs of the complete dentures were manufactured and randomly divided into three groups (n = 10): (1) invested with type III stone in monomaxillary PVC flask; (2) invested with type III stone in bimaxillary PVC flask; and (3) invested with laboratory silicone in bimaxillary PVC flask. Dentures were polymerised by microwave, and 12 linear distances were measured before and after denture processing. Data were analysed by one‐way anova , considering manufacturing technique as the study factor. Tukey’s HSD was used as post hocanova (p = 0.05). Results: Most of the linear distances were comparable for all groups. All transversal maxillary and mandibular distances were higher for group 1 compared with groups 2 and 3 (p < 0.05), except the distance 3–6 for mandibular arch, in which no difference was found between groups (p < 0.05). Both maxillary diagonal distances were higher in group 1 (p < 0.05), and no differences were found among all groups for mandibular measurements. Conclusions: Double flasking technique independent on the investment material is shown to be the most effective method to reduce changes in artificial teeth positioning.     

Effect of pre-processing methods on bond strength between acrylic resin teeth and acrylic denture base resin

doi: 10.1111/j.1741‐2358.2011.00480.x
Effect of pre‐processing methods on bond strength between acrylic resin teeth and acrylic denture base resin Objectives: This study evaluated the effects of various pre‐processing methods on the bond strength between resin and denture teeth. Backgrounds: Debonding of acrylic resin teeth from denture base material is a problem for patients wearing complete dentures. Materials and Methods: Four experimental groups (n = 30) were investigated by subjecting tooth–resin bonding to tensile loading. Specimens were prepared and tested according to the methods of the International Standards Organization (ISO 22112:2005) using a special assembly. Four pre‐processing surface treatments of teeth were applied: (i) ST₁, no treatment applied (control); (ii) ST₂, wax solvent (Dewaks, Faber Kimya & Ilaç, Turkey); (iii) ST₃, boiling water followed by conditioning with methyl methacrylate (MMA) monomer (Meliodent, Bayer Dental, Germany); (iv) ST₄, boiling water followed by wax solvent agent and finally MMA monomer application. Bond strength test was performed using a universal testing machine. Results: All the strength values of the test groups were within clinically acceptable limits. The lowest values were from the ST₁ group and the highest values were in the ST₄ group. Conclusions: Wax elimination methods affected bonding strength. Application of wax solvent and MMA monomer to the ridge lap surfaces of the teeth gave the best results. In clinical practice, this application procedure may decrease the bonding failure of denture teeth.     

Assessment of changes in oral health‐related quality of life among patients with complete denture before and 1 month post‐insertion using Geriatric Oral Health Assessment Index

doi:10.1111/j.1741‐2358.2009.00323.x
Assessment of changes in oral health‐related quality of life among patients with complete denture before and 1 month post‐insertion using Geriatric Oral Health Assessment Index Objective: Geriatric Oral Health Assessment Index (GOHAI) is a 12‐item measure of “patient‐reported oral functional problems” intended for use in the assessment of the effectiveness of dental treatment. Design and Setting: As there is scanty literature available on GOHAI in the Indian population, the present study was undertaken to assess the changes in GOHAI before and 1 month after placement of dentures in completely edentulous patients reporting to a dental hospital at Indore, India. Measurements: The GOHAI questionnaire was completed by the examiner who interviewed the patients (n = 35) before placement of complete dentures and 1 month later. Mean, median values were calculated and the data were analysed using Wilcoxon signed‐rank test. Results: When overall mean was considered, the GOHAI scores increased from 27.48 to 30.19 (p = 0.002; highly significant). Conclusion: Patients reported improvement in functional changes after placement of complete dentures.     

Insertion and follow‐up of complete dentures: a literature review

Gerodontology 2010; 00; doi: 10.1111/j.1741‐2358.2010.00368.x Insertion and follow‐up of complete dentures: a literature review Objective: The aim of this study was to present the importance of clinical procedures related to insertion and follow‐up of complete dentures in elderly patients. Materials and Methods: The success of rehabilitation with complete dentures results from the accuracy of clinical and laboratorial procedures that makes the denture insertion an important step of treatment. Conclusion: The follow‐up and professional maintenance of function and hygiene facilitates long‐term efficiency.     

The effect of denture quality attributes on satisfaction and eating difficulties

Objectives: The development of a measure, with complimentary normative and perceived needs, for the investigation of functional impairment of individual patients and the investigation of the physical causative bases of impairment. Subjects: A consecutive sample of 119 complete denture (CD) wearers attending a Greek department of prosthetic dentistry took part in the study. All subjects presented with some complaint(s) of their dentures. Method: Functional assessment of dentures (FAD) criteria and structured questionnaires were used covering denture satisfaction (DS) and food difficulties with CDs. The questions used a five‐point Likert scale. Results: The results showed that there were statistically significant associations between satisfaction from dentures and eating specified foods. Statistically significant associations were also found between denture qualities and movement of upper dentures and difficulty eating specified foods, but not with an open question on the difficulty of eating unspecified foods. Conclusions: This study successfully validated a suitable model for the combined evaluation of denture quality with clear diagnostic criteria and closed questions on DS and perceived difficulties when eating specified foods. This could predict the need for treatment, monitor the impact of care and provide a feasible measure to meet the need of everyday clinical situations.     

Attitudes and usage of denture adhesives by complete denture wearers: a survey in Greece and the Netherlands

doi: 10.1111/j.1741‐2358.2011.00566.x
Attitudes and usage of denture adhesives by complete denture wearers: a survey in Greece and the Netherlands Objective: To explore whether there are differences in usage of and attitudes towards denture adhesives among patients in two countries. Background: There are no multi‐country surveys concerning usage of and attitudes towards denture adhesives from complete denture wearers. Materials and methods: The survey took place in Greece and the Netherlands with a sample of 284 and 165 consecutive complete denture wearers, respectively, by using a 9‐item prepared questionnaire. Statistical analysis relied on chi‐square test at α = 0.05. Results: In this survey, 26 and 20% of Greek and Dutch patients, respectively, had tried denture adhesive, but only 27% of them in Greece as well as in the Netherlands currently used it; 49% of the Greek and 45% of the Dutch participants rated the overall performance of adhesives as good. Between the two populations, no differences were identified in a majority of the research variables, except where 27% of Greeks answered that they did not know the existence of denture adhesives compared to none of the Dutch patients and when 90% of the Dutch contrary to 70% of Greeks reported that they did not need denture adhesives as they could manage their dentures well. Conclusion: The usage of and attitudes towards denture adhesives between the Greek and Dutch sample were similar with only two exceptions concerning the knowledge of existence and the need of using denture adhesives.     

Bond strength of denture teeth to acrylic resin: effect of thermocycling and polymerisation methods

Background: Failure of bonding between acrylic resin teeth and denture base material is a considerable problem for patients who wear complete dentures. Objective: The purpose of this study was to evaluate the bond strength between acrylic resins and resin denture teeth with different thermocycling and polymerisation methods. Materials and methods: Microwave‐polymerised (Onda‐Cryl), heat‐polymerised (Clássico) and autopolymerising (Jet) acrylic resins and resin denture tooth (Biotone) were used. The acrylic resins were polymerised according to the following: (A) microwave – fast cycle, Onda‐Cryl; (B) microwave – long cycle, Onda‐Cryl; (C) microwave – manufacturer’s cycle, Onda‐Cryl; (T) water bath – long cycle, Clássico; and (Q) bench polymerisation cycle, Jet. Twenty specimens were prepared for each polymerisation method. Ten were thermocycled, and 10 did not receive thermocycling. For the purpose of the study, a shear test was used. Data were analysed with the Kruskal–Wallis test and Dunn’s multiple comparisons test (p = 0.05). Results: Cycles B, C and T were similar (p > 0.05), and had statistically higher bonding values than cycles A and Q (p < 0.05) for the thermocycled and non‐thermocycled groups. For all cycles, there were no statistically significant differences between thermocycled and non‐thermocycled groups (p > 0.05), except for cycle Q (p = 0.0038). Conclusion: Thermocycling decreased the bond strength, but not significantly for microwave and heat‐polymerised cycles. Regarding the bond strength of denture teeth to acrylic resin, the fast microwave polymerisation cycle should be avoided when polymerising Onda‐Cryl acrylic resin. In addition, Jet acrylic resin is not adequate for use in denture repair.     

Relining of prosthesis with auto‐polymerizing hard denture reline resins: effect of post‐polymerization treatment on flexural strength

Background: It has been suggested that microwave irradiation and prosthesis immersion in hot water after its polymerization may improve mechanical and viscoelastic properties of acrylic resins. Purpose: This study was proposed to verify the influence of microwave post‐polymerization (PP) treatment over the flexural strength of thermo‐polymerizing acrylic resin specimens (QC‐20) relined or not with two different composition hard chairside auto‐polymerizing reliners [Kooliner (K) and New Truliner (NT)]. Materials and Methods: For this study, 50 specimens of 64 × 10 × 3.3 mm were polymerized and distributed into five groups. G1 (control) specimens without relining and PP; G2 specimens relined with K, without PP; G3 specimens relined with NT, without PP; G4 specimens relined with K, with PP (microwave irradiation with 650 W for 5 min); G5 specimens relined with NT, with PP. Tests were performed on a universal testing machine Instron 4411 with compression speed of 5 mm/min. Results: Specimens of K without PP did not show statistically different results (p < 0.05) when compared with control. However, when submitted to PP these specimens showed a significant increase in flexural strength. Specimens of NT showed the lowest flexural strength of all groups, with or without PP when compared with control and K groups. Conclusion: Microwave PP (650 W for 5 min) proved to be an effective method of improving the flexural strength of K relined prosthesis. However, it did not seem to affect NT specimens.     

Evaluation of the occlusion vertical dimension of complete dentures after microwave disinfection

doi: 10.1111/j.1741‐2358.2011.00567.x Evaluation of the occlusion vertical dimension of complete dentures after microwave disinfection Objectives: An increase in occlusal vertical dimension (OVD) after microwave disinfection may result in the need for adjustments in the complete dentures. This in vitro study evaluated the increase in OVD of maxillary complete dentures submitted to microwave disinfection protocols. Material and methods: Thirty sets of complete dentures were evaluated as follows: Group 1–15 sets had the maxillary complete dentures submitted to microwave disinfection (650 W/3 min), once a week, for 4 weeks. Group 2–15 sets had the maxillary complete dentures submitted to microwave disinfection (650 W/3 min), three times a week, for 4 weeks. The vertical dimension was measured with a micrometre (in mm) before disinfection protocols (baseline readings) and after each week of disinfection. Data were analysed using Wilcoxon and Friedman tests (α = 0.05). Results: For Group 1, no significant difference was found between the increases in OVD and zero, and no significant difference was found between the weeks. For Group 2, the increases in OVD were significantly greater than zero, and the Friedman test showed that weeks 3 and 4 had significantly greater changes than week 1 and that week 4 had significantly greater change than week 2. Conclusion: Microwave disinfection only promoted significant increase in OVD in Group 2, in which the values increased progressively.