Digital technologies have become an integral part of complete denture restoration.With advancement in computer-aided design and computer-aided manufacturing(CAD/CAM),tools such as intraoral scanning,facial scanning,3D...Digital technologies have become an integral part of complete denture restoration.With advancement in computer-aided design and computer-aided manufacturing(CAD/CAM),tools such as intraoral scanning,facial scanning,3D printing,and numerical control machining are reshaping the workflow of complete denture restoration.Unlike conventional methods that rely heavily on clinical experience and manual techniques,digital technologies offer greater precision,predictability,and efficacy.They also streamline the process by reducing the number of patient visits and improving overall comfort.Despite these improvements,the clinical application of digital complete denture restoration still faces challenges that require further standardization.The major issues include appropriate case selection,establishing consistent digital workflows,and evaluating long-term outcomes.To address these challenges and provide clinical guidance for practitioners,this expert consensus outlines the principles,advantages,and limitations of digital complete denture technology.The aim of this review was to offer practical recommendations on indications,clinical procedures and precautions,evaluation metrics,and outcome assessment to support digital restoration of complete denture in clinical practice.展开更多
Objective:Denture-associated infections are common among older adult diabetic patients,particularly those with poor glycemic control.Chronic hyperglycemia promotes fungal adhesion,biofilm formation,and impaired oral i...Objective:Denture-associated infections are common among older adult diabetic patients,particularly those with poor glycemic control.Chronic hyperglycemia promotes fungal adhesion,biofilm formation,and impaired oral immunity,while few studies have investigated how blood glucose levels and hygiene behaviors jointly influence microbial colonization on dentures.This study aimed to investigate the association between glycemic control,denture hygiene behaviors,and fungal colonization among older adult diabetic denture wearers in Nakhon Si Thammarat,Thailand.Methods:In this cross-sectional study of 80 diabetic denture wearers,we stratified participants by HbA1c status(≤7.0%vs>7.0%)and quantified denture fungal burden alongside hygiene practices.Denture swabs were cultured on Sabouraud dextrose agar for quantitative fungal enumeration and species identification using VITEK MS PRIME.Results:Patients with poor glycemic control exhibited significantly higher fungal loads(P<0.001).HbA1c emerged as the independent predictor in multiple regression analysis(β=0.35,P=0.041).Species level profiling revealed Candida albicans as dominant in uncontrolled patients followed by C.glabrata,C.tropicalis,Trichosporon asahii,and C.nivariensis.Conversely,C.dubliniensis and C.pelliculosa were uniquely identified in patients with good glycemic control.Hygiene practices revealed that brushing combined with chemical cleansing significantly reduced fungal concentration compared with rinsing with water alone(P=0.013).Participants who cleaned their dentures after every meal also exhibited significantly lower fungal counts than those who cleaned only once daily(P=0.05).Conclusion:Poor glycemic control is strongly associated with denture mycobiome dysbiosis and increased fungal diversity in diabetic patients.The findings underscore HbA1c as a potential microbial risk indicator and emphasize the need for integrated diabetes management and targeted oral hygiene interventions to prevent denture-related fungal infections among older adults.展开更多
BACKGROUND The primary issue in managing edentulous patients is the severely resorbed mandibular ridge,particularly in older individuals with diminished adaptive capacities.This compromised situation leads to the fabr...BACKGROUND The primary issue in managing edentulous patients is the severely resorbed mandibular ridge,particularly in older individuals with diminished adaptive capacities.This compromised situation leads to the fabrication of inadequate dentures that lack retention and stability,potentially causing psychosocial issues.AIM To determine the difference in retentive capacity between three attachment systems in implant-retained overdentures.METHODS Three edentulous mandibular models were fabricated using heat-cured polymethacrylate resin,with two implant replicas placed in the intra-foraminal region of each model.30 acrylic resin mandibular overdentures were fabricated with provisions for three different overdenture attachment systems:A prefabricated ball/O-ring attachment,a locator attachment system,and an equator attachment system.Each model was subjected to 15000 pulls using a universal testing machine to remove the overdenture from the acrylic model and the force data were recorded.RESULTS The ball/O-ring attachment system demonstrated superior retentive capacity for 15 years,while the locator and equator attachment systems maintained excellent retentive capacity for 5 years.CONCLUSION The ball/O-ring attachment system outperformed better than the other two attachment systems regarding retentive capacity.The locator and equator attachment systems presented sufficient retentive abilities until 15000 cycles.After 7500 cycles,significant differences in retentive force between the systems evolved.展开更多
Objective:This study investigated the effect of proximal contact strength on the three-dimensional displacements of cantilever fixed partial denture(CFPD) under vertically concentrated loading with digital laser speck...Objective:This study investigated the effect of proximal contact strength on the three-dimensional displacements of cantilever fixed partial denture(CFPD) under vertically concentrated loading with digital laser speckle(DLS) technique.Methods:Fresh mandible of beagle dog was used to establish the implant-supported CFPD for specimen.DLS technique was employed for measuring the three-dimensional displacement of the prosthesis under vertically concentrated loading ranging from 200 to 3 000 g.The effect of the contact tightness on the displacement of CFPD was investigated by means of changing the contact tightness.Results:When an axial concentrated loading was exerted on the pontic of the implant-supported CFPD,the displacement of the CFPD was the greatest.The displacement of the prosthesis decreased with the increase of contact strength.When the contact strength was 0,0.95,and 3.25 N,the displacement of the buccolingual direction was smaller than that of the mesiodistal direction but greater than that of the occlusogingival direction.When the force on the contact area was 6.50 N,the mesiodistal displacement of the prosthesis was the biggest while the buccolingual displacement was the smallest.Conclusions:The implant supported CFPD is an effective therapy for fully or partially edentulous patients.The restoration of the contact area and the selection of the appropriate contact strength can reduce the displacement of the CFPD,and get a better stress distribution.The most appropriate force value is 3.25 N in this study.展开更多
Objective:To investigate the effect of Phyllanthus emblica(P.emblica) Linn,ethanolic extract on the adhesion of Candida albicans(C.albicans) to human buccal epithelial cells(BECs) and denture acrylic surfaces.Methods:...Objective:To investigate the effect of Phyllanthus emblica(P.emblica) Linn,ethanolic extract on the adhesion of Candida albicans(C.albicans) to human buccal epithelial cells(BECs) and denture acrylic surfaces.Methods:Human BECs and transparent acrylic strips were pretreated with ethanolic extract solution of P.emblica fruits at concentration ranged from 18.7 to 300 mg/mL.After washing BECs and the strips were inoculated with three strains of C.albicans (ATCC 10281 and two clinical isolates)(10~7 cells/mL).Normal saline solution(NSS) and 0.2% chlorhexidine gluconate were used as negative and positive controls,respectively.BECs were harvested on 12μm-polycarbonate filters(Millipore,USA).The membrane filters and the strips were stained with Gram stain.Adherent yeast cells on 100 randomly selected epithelial cells and 20 randomly selected fields on each strip were counted under microscope.The statistical significance was calculated by Kruskal-Wallis and Tukey tests at a significant level of P【0.05. Results:Significant lower numbers of all strains of yeasts adhering to BECs and acrylic strips were observed after exposure to 75-300 mg/mL of plant extract compared with NSS.Conclusions: The present study demonstrates that P.emblica ethanolic extract interferes with the adhesion of C. albicans to BECs and denture acrylic surfaces in vitro.展开更多
The aim of the study was to evaluate the effect of adding acrylamide monomer （AAm） on the characterization, flexural strength, flexural modulus and thermal degradation temperature of poly（methyl methacrylate） （P...The aim of the study was to evaluate the effect of adding acrylamide monomer （AAm） on the characterization, flexural strength, flexural modulus and thermal degradation temperature of poly（methyl methacrylate） （PMMA） denture-base resins. Specimens （n= 10） were fabricated from a conventional heat-activated QC-20 （Qc-） and a microwave heat-activated Acron MC （Ac-） PMMA resins. Powder/ liquid ratio followed the manufacturer＇s instructions for the control groups （Qc-c and Ac-c） and for the copolymer groups, the resins were prepared with 5% （-5）, 10% （- 10）, 15% （- 15） and 20% （-20） acrylamide contents, according to the molecular weight ratio, respectively. The flexural strength and flexural modulus were measured by a three-point bending test. The data obtained were statistically analyzed by Kruskal-Wallis test （a=O.05） to determine significant differences between the groups, The chemical structures of the resins were characterized by the nuclear magnetic resonance spectroscopy. Thermal stabilities were determined by thermogravimetric analysis （TGA） with a heating rate of 10 ~C.min-1 from 35 ~C to 600 ~C. Control groups from both acrylic resins showed the lowest flexural strength values. Qc-15 showed significant increase in the flexural strength when compared to Qc-c （P〈O.01）. Ac-10 and Ac-15 showed significance when compared to Ac-c （P〈O.01）. Acrylamide incorporation increased the elastic modulus in Qc-10, Qc-15 and Qc-20 when compared to Qc-c （P〈0.01）. Also significant increase was observed in Ac-10, Ac-15 and Ac-20 copolymer groups when compared to Ac-c （P〈0.01）. According to the 1H-nuclear magnetic resonance （NMR） results, acrylamide copolymerization was confirmed in the experimental groups. TGA results showed that the thermal stability of PMMA is increased by the insertion of AAm.展开更多
Severe dementia, including Alzheimer’s disease, is intractable and progressive. The purpose of this study was to document the improvement observed in two cases of severe dementia after denture placement. The subjects...Severe dementia, including Alzheimer’s disease, is intractable and progressive. The purpose of this study was to document the improvement observed in two cases of severe dementia after denture placement. The subjects, two women in their 70s with severe dementia, were diagnosed with Alzheimer’s disease by the medical doctors in charge of their cases. In the first case, the subject’s symptoms included severe disorientation, impaired communication, and a tendency to wander. Two weeks after a lower complete denture placement, she was able to greet others. Five weeks later, she was able to communicate and precisely read an analog clock. Her condition continued to improve for at least 3 months. In the second case, the subject’s mouth was always open. She was bedridden in a vegetative state and hardly moved, talked, or laughed;it was impossible to communicate with her. Only a few seconds after an upper complete denture placement, she started to talk, albeit unintelligibly. Two weeks after a lower complete denture placement, she could communicate normally, laugh, and walk without help. Although the underlying mechanism has not yet been clarified, the author hypothesizes that positive signals from the oral area are transferred to the brain as positive stimulation via the trigeminal nerve, the largest cranial nerve.展开更多
Objective:To investigate effect of Boesenbergia pandurata(B.pandurata) rhizome extract on adhesion of Candida albicans(C.albicans) to acrylic surface.Methods:Transparent acrylic strips were prepared and divided into t...Objective:To investigate effect of Boesenbergia pandurata(B.pandurata) rhizome extract on adhesion of Candida albicans(C.albicans) to acrylic surface.Methods:Transparent acrylic strips were prepared and divided into three groups with pretreatment by extract solution of B. pandurata rhizome at concentration of 25,50 and 100 mg/mL,respectively.After washing, the strips were then inoculated with two strains of C.albicans(ATCC13803 and the clinical isolate)(10~7 cells/mL).Normal saline solution and 0.2%chlorhexidine gluconate were used as negative and positive controls,respectively.Stained the strips with modified Cram stain without counterstain.Adherent yeast cells were direct counted under microscope(OlympusCX31, Japan) in 20 randomly selected fields on each strip.The statistical significance was calculated by Kruskal-Wallis and Mann-Whitney non-parametric tests at a significance level of P 【 0.05.Results:Pretreatment with B.pandurata extract significantly reduced the adhesion of both strains of C.albicans to acrylic surfaces in a dose dependent manner.Conclusions: This observation indicates that B.pandurata extract has an inhibitory effect on the ability of C. albicans to adhere to denture acrylic and could be employed as an antifungal agent for preventing denture stomatitis.展开更多
Objective：To study the relationship between plasma treatment time acrylic resin denture material in the size of 2 mm × 10 mm × 10 mm. and efficacy. Methods：Test specimens were prepared from an Plasma treat...Objective：To study the relationship between plasma treatment time acrylic resin denture material in the size of 2 mm × 10 mm × 10 mm. and efficacy. Methods：Test specimens were prepared from an Plasma treatment was carried out on the surface of Polymethyl methacrylate（PMMA） at different time. XPS studies, IR spectra studies and measurement of wetting angle were performed. Results： XPS showed the peak corresponding to C-O getting higher as the treatment proceeded, however at 120 seconds, the peak did not increase any longer and partly crossed with the peak at the duration of 60 seconds. IR spectra showed the wave corresponding to C-H was reduced as O2-plasma treatment proceeded, and then changed little, Wetting angle initially decreased dramatically, however, as the reaction proceeded, wetting angle increased slightly. Conclusion：Equilibrium was reached for introducing oxygen-containing groups and changing of C-H. As the treatment proceeded, wetting angle increased slightly.展开更多
The aim of this research is to clarify whether the midline axis of the complete upper denture (CUD) is the axis of its torsion during loading, apart from the known bending deflection. Furthermore the present study is ...The aim of this research is to clarify whether the midline axis of the complete upper denture (CUD) is the axis of its torsion during loading, apart from the known bending deflection. Furthermore the present study is intended to estimate the influence of the anterior notches on the torsional deformation of the CUD. Using commercial edentulous molds and standardized procedures, six identical CUDs were fabricated with an initial fraenal notch of 5 mm. Two additional notch conditions were produced by deepening the notch to a total depth of 9 mm and by creating an incisal diastema of 7 mm. Five biaxial (also known as “fish bone”) strain gauges were cemented onto the palatal section of the dentures so that their middle axis coincided with the midline axis of the outer surface of the denture. For the denture specimen used in this study, the specific point of torsion was detected 2 cm from the point of contact of the two artificial central incisors. The presence of a deep fraenal notch and the combination of the deep fraenal notch with the presence of an incisal diastema increased the torsion of the CUD to a significant level (P = 0.006 and P = 0.05, respectively). It was shown that the midline can be the CUD’s axis of torsion. Biaxial strain gauges could be a reliable method of measuring the torsional deformation of the CUD.展开更多
This article reviews the literatures dealing with the lingualized occlusion of complete denture including the origin,development and research.Lingualized occlusion is a valuable concept because many advantages of anat...This article reviews the literatures dealing with the lingualized occlusion of complete denture including the origin,development and research.Lingualized occlusion is a valuable concept because many advantages of anatomic and nonanatomic occlusions are retained,satisfactory occlusion is easily obtained,balanced occlusion can be accomplished.展开更多
This study was conducted to investigate the maxillary denture bases and occlusal discrepancies using the Vertex Thermosens in comparison with the conventional polymethyl-methacrylate materials. Twenty maxillary dentur...This study was conducted to investigate the maxillary denture bases and occlusal discrepancies using the Vertex Thermosens in comparison with the conventional polymethyl-methacrylate materials. Twenty maxillary denture bases were prepared from the Vertex ThermoSens and a conventional heat-cured denture base materials. Acrylic maxillary second molars were arranged in their respective positions on the ridge. After curing of both types of denture bases, they were deflasked with their respective master casts. Reference points were prepared for measurements of the antero-posterior and cross-arch dimensions at the denture borders using caliper device. Furthermore, the teeth discrepancies were measured between reference points in the ligual aspect of the second maxillary molars. The recorded data was analyzed using SPSS statistical software version 20. The results showed initial shrinkage of both denture bases in the antero-posterior and cross-arch dimensions immediately after decasting. This contraction was compensated gradually during storage in water up to 2 weeks. Regarding the variable time, there was a significant difference between the tested materials. Moreover, the results revealed occlusal discrepancies and shifting of teeth inward immediately after decasting, followed by outward movement after storage in water for 2 weeks. Regarding the variables time and materials, there were significant differences. Both materials exhibited inward shrinkage in the antero-posterior and cross-arch dimensions immediately after decasting. Both denture bases showed inward shifting of teeth immediately after decasting, followed by outward movement after storage in water up to 2 weeks.展开更多
Aim: Both conventional and flexible resins may show color alteration due to intrinsic and extrinsic factors. The aim of this study was to evaluate the color changes of the polyamid and heat polymerized acrylic denture...Aim: Both conventional and flexible resins may show color alteration due to intrinsic and extrinsic factors. The aim of this study was to evaluate the color changes of the polyamid and heat polymerized acrylic denture base materials in storage of different staining solutions. Methods: Two denture base materials were used in this study. The speciemens were stored in two staining solutions (tea, coffee), distilled water and denture cleaner. For each group, 14 speciemens (25 × 15 × 2.5 mm) were prepared. The color of speciemens was measured using a colorimeter according to the CIE L*a*b* color scale. The color changes of speciemens were evaluated before and after 7 and 30 days. All data recorded were taken by the same investigator to minimize inconstancy of technique. The data were analyzed statistically by repeated measures analysis of variance and Tukey honestly significant difference multiple comparison tests. It was found no statistically significant difference between solutions (P > 0.05). Results: Polyamid denture base resin displayed the greatest colour change when compared to polymetyhl methacrylate denture base resin (P < 0.001). Polyamid material indicated the highest value (ΔE: 7.28) in coffee solution for 7 days. Significance: The colour stability of polymetyhl methacrylate denture base resin is greater than polyamid denture base resin.展开更多
A novel kind of denture base nanocomposite was prepared by polymethyl methyacrylate（PMMA） and cethyltrimethylammonium bromide modified organic montmorillonite （OMMT）. The dispersion of montmorillonite in the polym...A novel kind of denture base nanocomposite was prepared by polymethyl methyacrylate（PMMA） and cethyltrimethylammonium bromide modified organic montmorillonite （OMMT）. The dispersion of montmorillonite in the polymer matrix was characterized by x-ray diffraction （XRD） and transimission electron microscope （TEM）.The content of residual MMA in nanocomposites and the amount of MMA released to water from nanocomposites were determined by gas chromatography （GC）. The analysis of TEM and XRD showed that exfoliated-intercalated and intercalated nanocomposites were formed when the content of OMMT was 3% and 5% in the PMMA powder respectively. The results of GC showed that the residual MMA increased with the increase of OMMT content in the polymer matrix. After 7 days in water, the amount of MMA released into water from the nanocomposites tended to be stable. The results of one-way ANOVA and t-test showed that OMMT gave a significant increase of residual MMA concentration （p〈0.05） in nanocomposites.展开更多
The effects of 3 chairside polishing kits and mechanical brushing on the surface roughness of 3 different acrylic denture base resins were compared. Acrylic denture base resins （auto-polymerizing, heat-polymerizing, ...The effects of 3 chairside polishing kits and mechanical brushing on the surface roughness of 3 different acrylic denture base resins were compared. Acrylic denture base resins （auto-polymerizing, heat-polymerizing, injected heat-polymerizing resins） were examined after a tungsten carbide bur, and after chairside polishing using 3 polishing kits and pumice. The specimens were subjected to mechanical brushing using a wear tester to simulate 30 000 strokes of brushing. The surface roughness of the acrylic denture base resin specimens was measured using a contact pro-filometer. After the test, the random polished acrylic resins were evaluated by scanning electron mi-croscopy （SEM） and atomic force microscopy （AFM）. Acrylic denture base resins polished using the 3 types of polishing kits had a smoother surface than those finished with the tungsten carbide bur （p〈0.05）. The surface of the resin polished by a TC cutter exceeded the Ra of 0.2 μm （p〈0.05）. The auto-polymerizing resin showed a significantly higher surface roughness than the heat-polymerizing resin and injected heat-polymerizing resin （p〉0.05）. In the case of polishing step wise, there was almost no change in surface roughness after brushing （p〉0.05）.展开更多
To develop a new kind of denture adhesive （DA）, then to evaluate its mechanical and chemical properties, polyethylene oxide, methyl cellulose, sodium alginate, and cellulose ether, were viewed as four main factors, ...To develop a new kind of denture adhesive （DA）, then to evaluate its mechanical and chemical properties, polyethylene oxide, methyl cellulose, sodium alginate, and cellulose ether, were viewed as four main factors, which would affect bonding load of DA, while two levels of each component were differentiated. Following table L12（211）, twelve different formulae were designed by orthogonal design and bonding load values were recorded. According to bonding load of each formula, the optimized formula was selected out as this new adhesive material, Comfort-DA II. The changing of bonding load values of Comfort-DA II marinating in artificial saliva were measured, and an existing product, Protefix and Comfort-DA, were used as controls. Following initial load readings, samples and controls were measured from 1- to 12- hour intervals, respectively. Comfort-DA II was diluted at 1.0%, 2.0%, 3.3%, 5.0%, and 10.0% concentrations, and pH values were measured at 1-, 2-, 3-, 4-, 5-, 6-, and 8-hour intervals. Comfort-DA II presented as a pale-yellow paste. Group 6 gained the highest bonding load value of [193.8 （4.2）] N. The mean bonding load of Comfort-DA II was statistically different to Comfort-DA （p = 0.004） and Protefix （p = 0.006）. Comfort-DA II exhibited a progressive increase in pH value over time and was slightly alkaline. Comfort-DA II showed significantly elevated mechanical and chemical properties, comparing to Comfort-DA. The results also indicate that orthogonal design may be an efficacious way to develop new dental materials.展开更多
Introduction: Several techniques have been described by which a pair of dentures may be replicated. Case Report: The method described in this paper used materials readily available in a private practice to generate a ...Introduction: Several techniques have been described by which a pair of dentures may be replicated. Case Report: The method described in this paper used materials readily available in a private practice to generate a pair of duplicate dentures for a 74-year-old Black male, which captured all of the features of the patients’ existing pair. These were modified chair-side and used to capture vital information on fit, occlusion and aesthetics, forming a template which was transferred to the laboratory and used to generate new dentures via the traditional laboratory process. The same template was also used to generate a pair of “AvaDent Digital Dentures” by digital scanning and production of a digital denture template for try and then fabrication of the digital denture. Conclusion: The results of this pilot study show that this simple chair-side method of fabricating duplicate dentures can be incorporated successfully into the AvaDent Digital Denture fabrication process to generate a pair of dentures with comparability if not superior fit and aesthetics to a pair fabricated from the same template via the traditional laboratory process.展开更多
Removable partial dentures (RPDs) (conventional and implant-supported) treatment is considered a viable option to replace missing teeth as inexpensively as possible, but it has limitations. Objectives: This study repo...Removable partial dentures (RPDs) (conventional and implant-supported) treatment is considered a viable option to replace missing teeth as inexpensively as possible, but it has limitations. Objectives: This study reports the effect of gender and location (maxilla vs. mandible) on the clinical performance of removable partial dentures (RPDs). Materials and Methods: A total of 100 Patients who had RPDs delivered between 1990-1995 were evaluated. A 4-point scoring system was used to assess seventeen criteria. These criteria include acceptance, stability, support, retention, adaptation, occlusion, integrity, and design of the pros-theses, rest and rest seat preparation, occlusal wear, esthetics, phonetics, tissue condition, mobility of abutments, gingival and plaque indices. The data were analyzed using Kruskal-Wallis and Mann-Whitney U non-parametric statistical tests. Results: The results showed that acceptance of RPDs was rated the lowest. Other reasons for failure were poor retention, lack of integrity of the prostheses and inadequate adaptation. Retention and design of major connectors attributed to Mandibular RPD failure. Success rate of 75% was observed in male compared with 67.2% for female. Maxillary RPDs showed a higher success rate (78%) compared with the mandibular (70.1%). No significant statistical difference in Alpha scores between female and male patients and between maxillary and mandibular RPDs (p < 0.05). Conclusions: The clinical performance of RPDs showed a higher success rate in male patients compared to female patients and the maxillary RPDs showed a higher success rate compared to mandibular.展开更多
Objective: Infection control protocols dictate the disinfection of dentures. There are no products available which are designed for the specific use of disinfecting dentures. The objective of this study was to investi...Objective: Infection control protocols dictate the disinfection of dentures. There are no products available which are designed for the specific use of disinfecting dentures. The objective of this study was to investigate the impact of chemical disinfectants on elastic modulus, flexural strength and color stability of denture base resins. Methods: 256 specimens from four acrylic denture base resins were manufactured. Two cold-curing denture base resins: PalaXpress (Heraeus Kulzer, Hanau, Germany), Futura Gen (Schuetz Dental, Roßbach, Germany) and two heat-curing denture base resins: Paladon 65 (Heraeus Kulzer, Hanau, Germany), FuturAcryl 2000 (Schuetz Dental, Roßbach, Germany) were used. Three chemical disinfecting agents were tested: Impresept, D050 Instru-Gen, Stammopur DR. Specimens were stored in distilled water and in chemical disinfecting agents. They were divided randomly into groups. E-Modulus and flexural strength were measured using the three-point bending test. Color changes (ΔE) were determined spectrophotometrically. Results: The disinfection agents showed no significant influence on the E-modulus compared to distilled water (Acrylic vs. distilled water from (Futura Gen) 2688.80 ± 230.78 vs. 2766.60 ± 91.22 MPa to (PalaXpress) 3004.20 ± 26.40 vs. 2851.00 ± 95.23 MPa). Flexural strength after storage in distilled water and disinfection did not differ significantly (Acrylic vs. distilled water from (Paladon65) 27.28 ± 1.30 vs. 28.42 ± 0.84 N/mm2, (p > 0.05) to (PalaXpress) 30.88 ± 0.25 vs. 29.68 ± 0.79 N/mm2, p < 0.001). Disinfection caused a significant color change with Impresept of Paladon 65 (p ≤ 0.001), FuturaAcryl 2000 with Stammopur DR and D 050 Instru-Gen (p ≤ 0.001). Conclusions: The investigated disinfection agents did not influence elastic modulus and flexural strength of denture base resins negatively. ΔE-values were in a range of 1 to 2. Thus, the detected color changes may be marginal. Clinical relevance: Single use disinfections are feasible for acrylic dentures regarding to elastic modulus and flexural strength.展开更多
基金supported by National Natural Science Foundation of China(82325012)General project of State Key Laboratory of Oral&Maxillofacial Reconstruction and Regeneration(2024MS05).
文摘Digital technologies have become an integral part of complete denture restoration.With advancement in computer-aided design and computer-aided manufacturing(CAD/CAM),tools such as intraoral scanning,facial scanning,3D printing,and numerical control machining are reshaping the workflow of complete denture restoration.Unlike conventional methods that rely heavily on clinical experience and manual techniques,digital technologies offer greater precision,predictability,and efficacy.They also streamline the process by reducing the number of patient visits and improving overall comfort.Despite these improvements,the clinical application of digital complete denture restoration still faces challenges that require further standardization.The major issues include appropriate case selection,establishing consistent digital workflows,and evaluating long-term outcomes.To address these challenges and provide clinical guidance for practitioners,this expert consensus outlines the principles,advantages,and limitations of digital complete denture technology.The aim of this review was to offer practical recommendations on indications,clinical procedures and precautions,evaluation metrics,and outcome assessment to support digital restoration of complete denture in clinical practice.
文摘Objective:Denture-associated infections are common among older adult diabetic patients,particularly those with poor glycemic control.Chronic hyperglycemia promotes fungal adhesion,biofilm formation,and impaired oral immunity,while few studies have investigated how blood glucose levels and hygiene behaviors jointly influence microbial colonization on dentures.This study aimed to investigate the association between glycemic control,denture hygiene behaviors,and fungal colonization among older adult diabetic denture wearers in Nakhon Si Thammarat,Thailand.Methods:In this cross-sectional study of 80 diabetic denture wearers,we stratified participants by HbA1c status(≤7.0%vs>7.0%)and quantified denture fungal burden alongside hygiene practices.Denture swabs were cultured on Sabouraud dextrose agar for quantitative fungal enumeration and species identification using VITEK MS PRIME.Results:Patients with poor glycemic control exhibited significantly higher fungal loads(P<0.001).HbA1c emerged as the independent predictor in multiple regression analysis(β=0.35,P=0.041).Species level profiling revealed Candida albicans as dominant in uncontrolled patients followed by C.glabrata,C.tropicalis,Trichosporon asahii,and C.nivariensis.Conversely,C.dubliniensis and C.pelliculosa were uniquely identified in patients with good glycemic control.Hygiene practices revealed that brushing combined with chemical cleansing significantly reduced fungal concentration compared with rinsing with water alone(P=0.013).Participants who cleaned their dentures after every meal also exhibited significantly lower fungal counts than those who cleaned only once daily(P=0.05).Conclusion:Poor glycemic control is strongly associated with denture mycobiome dysbiosis and increased fungal diversity in diabetic patients.The findings underscore HbA1c as a potential microbial risk indicator and emphasize the need for integrated diabetes management and targeted oral hygiene interventions to prevent denture-related fungal infections among older adults.
文摘BACKGROUND The primary issue in managing edentulous patients is the severely resorbed mandibular ridge,particularly in older individuals with diminished adaptive capacities.This compromised situation leads to the fabrication of inadequate dentures that lack retention and stability,potentially causing psychosocial issues.AIM To determine the difference in retentive capacity between three attachment systems in implant-retained overdentures.METHODS Three edentulous mandibular models were fabricated using heat-cured polymethacrylate resin,with two implant replicas placed in the intra-foraminal region of each model.30 acrylic resin mandibular overdentures were fabricated with provisions for three different overdenture attachment systems:A prefabricated ball/O-ring attachment,a locator attachment system,and an equator attachment system.Each model was subjected to 15000 pulls using a universal testing machine to remove the overdenture from the acrylic model and the force data were recorded.RESULTS The ball/O-ring attachment system demonstrated superior retentive capacity for 15 years,while the locator and equator attachment systems maintained excellent retentive capacity for 5 years.CONCLUSION The ball/O-ring attachment system outperformed better than the other two attachment systems regarding retentive capacity.The locator and equator attachment systems presented sufficient retentive abilities until 15000 cycles.After 7500 cycles,significant differences in retentive force between the systems evolved.
文摘Objective:This study investigated the effect of proximal contact strength on the three-dimensional displacements of cantilever fixed partial denture(CFPD) under vertically concentrated loading with digital laser speckle(DLS) technique.Methods:Fresh mandible of beagle dog was used to establish the implant-supported CFPD for specimen.DLS technique was employed for measuring the three-dimensional displacement of the prosthesis under vertically concentrated loading ranging from 200 to 3 000 g.The effect of the contact tightness on the displacement of CFPD was investigated by means of changing the contact tightness.Results:When an axial concentrated loading was exerted on the pontic of the implant-supported CFPD,the displacement of the CFPD was the greatest.The displacement of the prosthesis decreased with the increase of contact strength.When the contact strength was 0,0.95,and 3.25 N,the displacement of the buccolingual direction was smaller than that of the mesiodistal direction but greater than that of the occlusogingival direction.When the force on the contact area was 6.50 N,the mesiodistal displacement of the prosthesis was the biggest while the buccolingual displacement was the smallest.Conclusions:The implant supported CFPD is an effective therapy for fully or partially edentulous patients.The restoration of the contact area and the selection of the appropriate contact strength can reduce the displacement of the CFPD,and get a better stress distribution.The most appropriate force value is 3.25 N in this study.
文摘Objective:To investigate the effect of Phyllanthus emblica(P.emblica) Linn,ethanolic extract on the adhesion of Candida albicans(C.albicans) to human buccal epithelial cells(BECs) and denture acrylic surfaces.Methods:Human BECs and transparent acrylic strips were pretreated with ethanolic extract solution of P.emblica fruits at concentration ranged from 18.7 to 300 mg/mL.After washing BECs and the strips were inoculated with three strains of C.albicans (ATCC 10281 and two clinical isolates)(10~7 cells/mL).Normal saline solution(NSS) and 0.2% chlorhexidine gluconate were used as negative and positive controls,respectively.BECs were harvested on 12μm-polycarbonate filters(Millipore,USA).The membrane filters and the strips were stained with Gram stain.Adherent yeast cells on 100 randomly selected epithelial cells and 20 randomly selected fields on each strip were counted under microscope.The statistical significance was calculated by Kruskal-Wallis and Tukey tests at a significant level of P【0.05. Results:Significant lower numbers of all strains of yeasts adhering to BECs and acrylic strips were observed after exposure to 75-300 mg/mL of plant extract compared with NSS.Conclusions: The present study demonstrates that P.emblica ethanolic extract interferes with the adhesion of C. albicans to BECs and denture acrylic surfaces in vitro.
文摘The aim of the study was to evaluate the effect of adding acrylamide monomer （AAm） on the characterization, flexural strength, flexural modulus and thermal degradation temperature of poly（methyl methacrylate） （PMMA） denture-base resins. Specimens （n= 10） were fabricated from a conventional heat-activated QC-20 （Qc-） and a microwave heat-activated Acron MC （Ac-） PMMA resins. Powder/ liquid ratio followed the manufacturer＇s instructions for the control groups （Qc-c and Ac-c） and for the copolymer groups, the resins were prepared with 5% （-5）, 10% （- 10）, 15% （- 15） and 20% （-20） acrylamide contents, according to the molecular weight ratio, respectively. The flexural strength and flexural modulus were measured by a three-point bending test. The data obtained were statistically analyzed by Kruskal-Wallis test （a=O.05） to determine significant differences between the groups, The chemical structures of the resins were characterized by the nuclear magnetic resonance spectroscopy. Thermal stabilities were determined by thermogravimetric analysis （TGA） with a heating rate of 10 ~C.min-1 from 35 ~C to 600 ~C. Control groups from both acrylic resins showed the lowest flexural strength values. Qc-15 showed significant increase in the flexural strength when compared to Qc-c （P〈O.01）. Ac-10 and Ac-15 showed significance when compared to Ac-c （P〈O.01）. Acrylamide incorporation increased the elastic modulus in Qc-10, Qc-15 and Qc-20 when compared to Qc-c （P〈0.01）. Also significant increase was observed in Ac-10, Ac-15 and Ac-20 copolymer groups when compared to Ac-c （P〈0.01）. According to the 1H-nuclear magnetic resonance （NMR） results, acrylamide copolymerization was confirmed in the experimental groups. TGA results showed that the thermal stability of PMMA is increased by the insertion of AAm.
文摘Severe dementia, including Alzheimer’s disease, is intractable and progressive. The purpose of this study was to document the improvement observed in two cases of severe dementia after denture placement. The subjects, two women in their 70s with severe dementia, were diagnosed with Alzheimer’s disease by the medical doctors in charge of their cases. In the first case, the subject’s symptoms included severe disorientation, impaired communication, and a tendency to wander. Two weeks after a lower complete denture placement, she was able to greet others. Five weeks later, she was able to communicate and precisely read an analog clock. Her condition continued to improve for at least 3 months. In the second case, the subject’s mouth was always open. She was bedridden in a vegetative state and hardly moved, talked, or laughed;it was impossible to communicate with her. Only a few seconds after an upper complete denture placement, she started to talk, albeit unintelligibly. Two weeks after a lower complete denture placement, she could communicate normally, laugh, and walk without help. Although the underlying mechanism has not yet been clarified, the author hypothesizes that positive signals from the oral area are transferred to the brain as positive stimulation via the trigeminal nerve, the largest cranial nerve.
文摘Objective:To investigate effect of Boesenbergia pandurata(B.pandurata) rhizome extract on adhesion of Candida albicans(C.albicans) to acrylic surface.Methods:Transparent acrylic strips were prepared and divided into three groups with pretreatment by extract solution of B. pandurata rhizome at concentration of 25,50 and 100 mg/mL,respectively.After washing, the strips were then inoculated with two strains of C.albicans(ATCC13803 and the clinical isolate)(10~7 cells/mL).Normal saline solution and 0.2%chlorhexidine gluconate were used as negative and positive controls,respectively.Stained the strips with modified Cram stain without counterstain.Adherent yeast cells were direct counted under microscope(OlympusCX31, Japan) in 20 randomly selected fields on each strip.The statistical significance was calculated by Kruskal-Wallis and Mann-Whitney non-parametric tests at a significance level of P 【 0.05.Results:Pretreatment with B.pandurata extract significantly reduced the adhesion of both strains of C.albicans to acrylic surfaces in a dose dependent manner.Conclusions: This observation indicates that B.pandurata extract has an inhibitory effect on the ability of C. albicans to adhere to denture acrylic and could be employed as an antifungal agent for preventing denture stomatitis.
基金This work was supported by Science Fund of Department of Education of Jiangsu Province(06KJD320125)
文摘Objective：To study the relationship between plasma treatment time acrylic resin denture material in the size of 2 mm × 10 mm × 10 mm. and efficacy. Methods：Test specimens were prepared from an Plasma treatment was carried out on the surface of Polymethyl methacrylate（PMMA） at different time. XPS studies, IR spectra studies and measurement of wetting angle were performed. Results： XPS showed the peak corresponding to C-O getting higher as the treatment proceeded, however at 120 seconds, the peak did not increase any longer and partly crossed with the peak at the duration of 60 seconds. IR spectra showed the wave corresponding to C-H was reduced as O2-plasma treatment proceeded, and then changed little, Wetting angle initially decreased dramatically, however, as the reaction proceeded, wetting angle increased slightly. Conclusion：Equilibrium was reached for introducing oxygen-containing groups and changing of C-H. As the treatment proceeded, wetting angle increased slightly.
文摘The aim of this research is to clarify whether the midline axis of the complete upper denture (CUD) is the axis of its torsion during loading, apart from the known bending deflection. Furthermore the present study is intended to estimate the influence of the anterior notches on the torsional deformation of the CUD. Using commercial edentulous molds and standardized procedures, six identical CUDs were fabricated with an initial fraenal notch of 5 mm. Two additional notch conditions were produced by deepening the notch to a total depth of 9 mm and by creating an incisal diastema of 7 mm. Five biaxial (also known as “fish bone”) strain gauges were cemented onto the palatal section of the dentures so that their middle axis coincided with the midline axis of the outer surface of the denture. For the denture specimen used in this study, the specific point of torsion was detected 2 cm from the point of contact of the two artificial central incisors. The presence of a deep fraenal notch and the combination of the deep fraenal notch with the presence of an incisal diastema increased the torsion of the CUD to a significant level (P = 0.006 and P = 0.05, respectively). It was shown that the midline can be the CUD’s axis of torsion. Biaxial strain gauges could be a reliable method of measuring the torsional deformation of the CUD.
文摘This article reviews the literatures dealing with the lingualized occlusion of complete denture including the origin,development and research.Lingualized occlusion is a valuable concept because many advantages of anatomic and nonanatomic occlusions are retained,satisfactory occlusion is easily obtained,balanced occlusion can be accomplished.
文摘This study was conducted to investigate the maxillary denture bases and occlusal discrepancies using the Vertex Thermosens in comparison with the conventional polymethyl-methacrylate materials. Twenty maxillary denture bases were prepared from the Vertex ThermoSens and a conventional heat-cured denture base materials. Acrylic maxillary second molars were arranged in their respective positions on the ridge. After curing of both types of denture bases, they were deflasked with their respective master casts. Reference points were prepared for measurements of the antero-posterior and cross-arch dimensions at the denture borders using caliper device. Furthermore, the teeth discrepancies were measured between reference points in the ligual aspect of the second maxillary molars. The recorded data was analyzed using SPSS statistical software version 20. The results showed initial shrinkage of both denture bases in the antero-posterior and cross-arch dimensions immediately after decasting. This contraction was compensated gradually during storage in water up to 2 weeks. Regarding the variable time, there was a significant difference between the tested materials. Moreover, the results revealed occlusal discrepancies and shifting of teeth inward immediately after decasting, followed by outward movement after storage in water for 2 weeks. Regarding the variables time and materials, there were significant differences. Both materials exhibited inward shrinkage in the antero-posterior and cross-arch dimensions immediately after decasting. Both denture bases showed inward shifting of teeth immediately after decasting, followed by outward movement after storage in water up to 2 weeks.
基金supported financially by the Department of Scientific Research Projects of Ataturk University(Project No.2003/158)and(Project no.2010/141).
文摘Aim: Both conventional and flexible resins may show color alteration due to intrinsic and extrinsic factors. The aim of this study was to evaluate the color changes of the polyamid and heat polymerized acrylic denture base materials in storage of different staining solutions. Methods: Two denture base materials were used in this study. The speciemens were stored in two staining solutions (tea, coffee), distilled water and denture cleaner. For each group, 14 speciemens (25 × 15 × 2.5 mm) were prepared. The color of speciemens was measured using a colorimeter according to the CIE L*a*b* color scale. The color changes of speciemens were evaluated before and after 7 and 30 days. All data recorded were taken by the same investigator to minimize inconstancy of technique. The data were analyzed statistically by repeated measures analysis of variance and Tukey honestly significant difference multiple comparison tests. It was found no statistically significant difference between solutions (P > 0.05). Results: Polyamid denture base resin displayed the greatest colour change when compared to polymetyhl methacrylate denture base resin (P < 0.001). Polyamid material indicated the highest value (ΔE: 7.28) in coffee solution for 7 days. Significance: The colour stability of polymetyhl methacrylate denture base resin is greater than polyamid denture base resin.
文摘A novel kind of denture base nanocomposite was prepared by polymethyl methyacrylate（PMMA） and cethyltrimethylammonium bromide modified organic montmorillonite （OMMT）. The dispersion of montmorillonite in the polymer matrix was characterized by x-ray diffraction （XRD） and transimission electron microscope （TEM）.The content of residual MMA in nanocomposites and the amount of MMA released to water from nanocomposites were determined by gas chromatography （GC）. The analysis of TEM and XRD showed that exfoliated-intercalated and intercalated nanocomposites were formed when the content of OMMT was 3% and 5% in the PMMA powder respectively. The results of GC showed that the residual MMA increased with the increase of OMMT content in the polymer matrix. After 7 days in water, the amount of MMA released into water from the nanocomposites tended to be stable. The results of one-way ANOVA and t-test showed that OMMT gave a significant increase of residual MMA concentration （p〈0.05） in nanocomposites.
文摘The effects of 3 chairside polishing kits and mechanical brushing on the surface roughness of 3 different acrylic denture base resins were compared. Acrylic denture base resins （auto-polymerizing, heat-polymerizing, injected heat-polymerizing resins） were examined after a tungsten carbide bur, and after chairside polishing using 3 polishing kits and pumice. The specimens were subjected to mechanical brushing using a wear tester to simulate 30 000 strokes of brushing. The surface roughness of the acrylic denture base resin specimens was measured using a contact pro-filometer. After the test, the random polished acrylic resins were evaluated by scanning electron mi-croscopy （SEM） and atomic force microscopy （AFM）. Acrylic denture base resins polished using the 3 types of polishing kits had a smoother surface than those finished with the tungsten carbide bur （p〈0.05）. The surface of the resin polished by a TC cutter exceeded the Ra of 0.2 μm （p〈0.05）. The auto-polymerizing resin showed a significantly higher surface roughness than the heat-polymerizing resin and injected heat-polymerizing resin （p〉0.05）. In the case of polishing step wise, there was almost no change in surface roughness after brushing （p〉0.05）.
基金Funded by the Science and Technology Planning Project of Guangdong Province, China (2010B060900045)
文摘To develop a new kind of denture adhesive （DA）, then to evaluate its mechanical and chemical properties, polyethylene oxide, methyl cellulose, sodium alginate, and cellulose ether, were viewed as four main factors, which would affect bonding load of DA, while two levels of each component were differentiated. Following table L12（211）, twelve different formulae were designed by orthogonal design and bonding load values were recorded. According to bonding load of each formula, the optimized formula was selected out as this new adhesive material, Comfort-DA II. The changing of bonding load values of Comfort-DA II marinating in artificial saliva were measured, and an existing product, Protefix and Comfort-DA, were used as controls. Following initial load readings, samples and controls were measured from 1- to 12- hour intervals, respectively. Comfort-DA II was diluted at 1.0%, 2.0%, 3.3%, 5.0%, and 10.0% concentrations, and pH values were measured at 1-, 2-, 3-, 4-, 5-, 6-, and 8-hour intervals. Comfort-DA II presented as a pale-yellow paste. Group 6 gained the highest bonding load value of [193.8 （4.2）] N. The mean bonding load of Comfort-DA II was statistically different to Comfort-DA （p = 0.004） and Protefix （p = 0.006）. Comfort-DA II exhibited a progressive increase in pH value over time and was slightly alkaline. Comfort-DA II showed significantly elevated mechanical and chemical properties, comparing to Comfort-DA. The results also indicate that orthogonal design may be an efficacious way to develop new dental materials.
文摘Introduction: Several techniques have been described by which a pair of dentures may be replicated. Case Report: The method described in this paper used materials readily available in a private practice to generate a pair of duplicate dentures for a 74-year-old Black male, which captured all of the features of the patients’ existing pair. These were modified chair-side and used to capture vital information on fit, occlusion and aesthetics, forming a template which was transferred to the laboratory and used to generate new dentures via the traditional laboratory process. The same template was also used to generate a pair of “AvaDent Digital Dentures” by digital scanning and production of a digital denture template for try and then fabrication of the digital denture. Conclusion: The results of this pilot study show that this simple chair-side method of fabricating duplicate dentures can be incorporated successfully into the AvaDent Digital Denture fabrication process to generate a pair of dentures with comparability if not superior fit and aesthetics to a pair fabricated from the same template via the traditional laboratory process.
文摘Removable partial dentures (RPDs) (conventional and implant-supported) treatment is considered a viable option to replace missing teeth as inexpensively as possible, but it has limitations. Objectives: This study reports the effect of gender and location (maxilla vs. mandible) on the clinical performance of removable partial dentures (RPDs). Materials and Methods: A total of 100 Patients who had RPDs delivered between 1990-1995 were evaluated. A 4-point scoring system was used to assess seventeen criteria. These criteria include acceptance, stability, support, retention, adaptation, occlusion, integrity, and design of the pros-theses, rest and rest seat preparation, occlusal wear, esthetics, phonetics, tissue condition, mobility of abutments, gingival and plaque indices. The data were analyzed using Kruskal-Wallis and Mann-Whitney U non-parametric statistical tests. Results: The results showed that acceptance of RPDs was rated the lowest. Other reasons for failure were poor retention, lack of integrity of the prostheses and inadequate adaptation. Retention and design of major connectors attributed to Mandibular RPD failure. Success rate of 75% was observed in male compared with 67.2% for female. Maxillary RPDs showed a higher success rate (78%) compared with the mandibular (70.1%). No significant statistical difference in Alpha scores between female and male patients and between maxillary and mandibular RPDs (p < 0.05). Conclusions: The clinical performance of RPDs showed a higher success rate in male patients compared to female patients and the maxillary RPDs showed a higher success rate compared to mandibular.
文摘Objective: Infection control protocols dictate the disinfection of dentures. There are no products available which are designed for the specific use of disinfecting dentures. The objective of this study was to investigate the impact of chemical disinfectants on elastic modulus, flexural strength and color stability of denture base resins. Methods: 256 specimens from four acrylic denture base resins were manufactured. Two cold-curing denture base resins: PalaXpress (Heraeus Kulzer, Hanau, Germany), Futura Gen (Schuetz Dental, Roßbach, Germany) and two heat-curing denture base resins: Paladon 65 (Heraeus Kulzer, Hanau, Germany), FuturAcryl 2000 (Schuetz Dental, Roßbach, Germany) were used. Three chemical disinfecting agents were tested: Impresept, D050 Instru-Gen, Stammopur DR. Specimens were stored in distilled water and in chemical disinfecting agents. They were divided randomly into groups. E-Modulus and flexural strength were measured using the three-point bending test. Color changes (ΔE) were determined spectrophotometrically. Results: The disinfection agents showed no significant influence on the E-modulus compared to distilled water (Acrylic vs. distilled water from (Futura Gen) 2688.80 ± 230.78 vs. 2766.60 ± 91.22 MPa to (PalaXpress) 3004.20 ± 26.40 vs. 2851.00 ± 95.23 MPa). Flexural strength after storage in distilled water and disinfection did not differ significantly (Acrylic vs. distilled water from (Paladon65) 27.28 ± 1.30 vs. 28.42 ± 0.84 N/mm2, (p > 0.05) to (PalaXpress) 30.88 ± 0.25 vs. 29.68 ± 0.79 N/mm2, p < 0.001). Disinfection caused a significant color change with Impresept of Paladon 65 (p ≤ 0.001), FuturaAcryl 2000 with Stammopur DR and D 050 Instru-Gen (p ≤ 0.001). Conclusions: The investigated disinfection agents did not influence elastic modulus and flexural strength of denture base resins negatively. ΔE-values were in a range of 1 to 2. Thus, the detected color changes may be marginal. Clinical relevance: Single use disinfections are feasible for acrylic dentures regarding to elastic modulus and flexural strength.
