Comparison of tensile bond strength of denture reline materials on denture bases fabricated with CAD-CAM technology.

STATEMENT OF PROBLEM: Studies that have analyzed the bond strength of resilient denture liners to milled denture bases are sparse, and the authors are unaware of research that has investigated the tensile bond strength of denture relining materials to 3D-printed denture bases. PURPOSE: The purpose of this in vitro study was to evaluate the tensile bond strength of both hard and soft denture reline materials on denture bases fabricated by 3D printing and computer-aided design and computer-aided manufacture (CAD-CAM) milling technology. MATERIAL AND METHODS: Injected, milled, and printed denture base specimens were fabricated (n=30) and bonded to 5 different denture reline materials: soft chairside reline (Coe Soft and PermaSoft), hard chairside reline (Tokuyama Rebase ii and Kooliner), and hard laboratory reline (ProBase Cold). Specimens of each reline material were divided into 5 groups (n=10) and were placed in distilled water for 24 hours before tensile testing. Maximum tensile stress values before failure were recorded, and the failure mode was also determined. The type of failure was analyzed by a scanning electron microscope. Statistics were analyzed with 2-way ANOVA and multiple comparison tests (α=.05). RESULTS: Overall, no statistically significant difference in tensile bond strength was found in the injected, milled, and printed denture groups. However, the printed denture base group demonstrated significantly lower values of tensile bond strength (P<.05) with PermaSoft, Tokuyama Rebase ii, and ProBase Cold groups than other denture base groups (milled and injected). The milled denture bases had the highest mean value of tensile bond strength with 4 of the 5 denture relining materials tested (Coe Soft, PermaSoft, Tokuyama Rebase ii, and Kooliner). No statistically significant difference (P>.05) was found among the injected, milled, and printed denture bases when relined with Kooliner. When comparing the denture reline type, the lowest values were seen with the soft chairside relining materials, and highest values with the hard laboratory reline material. Among the modes of failure, adhesive failures were observed predominantly with the printed denture base materials relined with soft chairside relining materials, while cohesive and mixed modes of failure were found in the milled and injected denture base groups. CONCLUSIONS: The printed denture bases had significantly lower tensile bond strength values than the injection and milled denture bases with the PermaSoft, Tokuyama Rebase ii, and ProBase Cold denture relines, while milled denture bases demonstrated the highest values of tensile bond strength for all chairside relining groups. In addition, the soft chairside relining materials showed the lowest tensile bond strength values regardless of the denture processing method with respect to the denture base type (injected, printed, and milled) compared with the hard relining materials.

Efeitos de customizações da prótese total mandibular sobre a qualidade de vida, força de mordida e eletromiografia de músculos da mastigação de pacientes edêntulos: um estudo clínico analítico intervencional / Effects of mandibular complete denture customizations on quality of life, bite force, and masticatory muscle electromyography in edentulous patients: an interventional analytical clinical study

Objetivo: Avaliar se customizações da prótese total mandibular (reembasamento e restabelecimento da dimensão vertical de oclusão) influenciam na amplitude eletromiográfica dos músculos masseter e temporal, força máxima de mordida e qualidade de vida relacionada à saúde oral de indivíduos edêntulos. Materiais e métodos: Usuários de próteses totais que usavam o mesmo par de próteses por mais do que 5 anos foram incluídos (sem disfunção temporomandibular) (n=15). Avaliações de qualidade de vida (Oral Health Impact Profile for Edentulous ­ OHIP-EDENT), força máxima de mordida, e eletromiografia dos músculos masseter e temporal foram realizadas em 5 tempos diferentes (T1 ­ próteses antigas originais; T2 ­ após 18 dias de uso da prótese mandibular reembasada; T3 ­ após 18 dias do restabelecimento da dimensão vertical de oclusão; e T4 e T5 ­ 30 e 100 dias de uso de novas próteses totais. Resultados: Não houve diferenças significativas entre os pontos de tempo para todos os testes eletromiográficos e de força máxima de mordida. O OHIP-EDENT mostrou que o reembasamento pode contribuir para uma maior adaptação da prótese total mandibular e conforto do paciente (T2), em contrapartida T3 foi associado com o desconforto do paciente (p<0.05). Conclusão: Baseado na avaliação de qualidade de vida relacionada à saúde oral, o reembasamento da prótese total mandibular ocasionou um aumento do conforto mastigatório para os pacientes, e o restabelecimento prévio da dimensão vertical de oclusão causou um desconforto para os pacientes. A amplitude eletromiográfica mostrou que as customizações realizadas neste estudo não aumentaram ou diminuíram o esforço mastigatório significativamente. Além disso, todos os valores de força máxima de mordida observados estavam dentro do clinicamente aceitável(AU)

Objective: To evaluate whether customizations of mandibular complete dentures (relining and restoration of the vertical dimension of occlusion) influence the electromyographic amplitude of the masseter and temporal muscles, maximum bite force and oral health-related quality of life of edentulous individuals. Materials and methods: Complete denture wearers who wore the same pair of dentures for more than 5 years were included (without temporomandibular dysfunction) (n=15). Assessments of quality of life (Oral Health Impact Profile for Edentulous ­ OHIP-EDENT), maximum bite force, and electromyography of the masseter and temporal muscles were performed at 5 different times (T1 - original old dentures; T2 - after 18 days of wearing relined mandibular denture; T3 - after 18 days of restoration of the vertical dimension of occlusion; and T4 and T5 - 30 and 100 days of wearing new complete dentures. Results: There were no significant differences between the time points for all electromyographic and maximum bite force tests. The OHIP-EDENT showed that relining can contribute to greater adaptation of the mandibular denture and patient comfort (T2), in contrast, T3 was associated with patient discomfort (p<0.05). Conclusion: Based on the assessment of quality of life related to oral health, the reline of the mandibular complete denture caused an increase in masticatory comfort for the patients, and the previous definitive restoration of the vertical dimension of occlusion caused discomfort for patients. The electromyographic amplitude showed that the customizations performed in this study did not significantly increase or decrease masticatory effort. In addition, all observed maximum bite force values were within the clinically acceptable range(AU)

Reabilitação prótetica convencional após remoção cirúrgica de hiperplasia fibrosa: relato de caso / Conventional prosthetic rehabilitation after surgical removal of fibrous hyperplasia: case report

O uso de próteses mal adaptadas pode ocasionar o surgimento de processos proliferativos não neoplásicos. A hiperplasia fibrosa inflamatória (HFI) é uma lesão benigna, proveniente de reação hiperplásica do tecido conjuntivo fibroso em resposta às injúrias crônicas de baixa intensidade. O objetivo do presente trabalho é relatar um caso clínico sobre remoção cirúrgica de HFI, seguida de reabilitação oral com próteses removíveis. Paciente de 75 anos do sexo masculino relatou que gostaria de fazer a troca da sua prótese, pois a mesma estava fraturada. Ao exame clínico intra-oral constatou-se que suas próteses possuíam higienização precária, e, a superior, possuía uma borda cortante que causou uma lesão hiperplásica na região de fundo de vestíbulo anterior. Quanto ao aspecto clínico, apresentava-se com consistência fibrosa e firme à palpação, de coloração semelhante a mucosa e assintomática. O plano de tratamento proposto foi reembasamento da prótese antiga com resina Soft Confort (Dencril, Brasil) eliminando as áreas que traumatizavam a mucosa, cirurgia pré-protética para a remoção da HFI, exame histopatológico e a confecção de novas próteses, sendo a superior prótese total convencional e a inferior prótese parcial removível. Observa-se a importância no cuidado do planejamento reabilitador protético dos pacientes, pois, como foi descrito neste caso, em algumas situações pode haver necessidade de lançarmos mão de diversas modalidades de tratamento prévias à reabilitação(AU)

The use of poorly adapted prostheses can lead to the emergence of non-neoplastic proliferative processes. Inflammatory fibrous hyperplasia (HFI) is a benign lesion, resulting from a hyperplastic reaction of fibrous connective tissue in response to low-intensity chronic injuries. The aim of the present study is to report a clinical case about surgical removal of HFI, followed by oral rehabilitation with removable prostheses. A 75-year-old male patient reported that he would like to change his prosthesis, because it was fractured. On intra-oral clinical examination, it was found that his prostheses had poor hygiene, and the upper one had a cutting edge that caused a hyperplastic lesion in the deep region of the anterior vestibule. As for the clinical aspect, it was fibrous and firm on palpation, mucosa-like and asymptomatic. The proposed treatment plan was to repurpose the old prosthesis with Soft Confort resin (Dencril, Brazil), eliminating the areas that traumatized the mucosa, pre-prosthetic surgery for the removal of HFI, histopathological examination and the making of new prostheses, the upper prosthesis being conventional total and the lower partial removable prosthesis. It is observed the importance in the care of the prosthetic rehabilitation planning of the patients, because, as it was described in this case, in some situations it may be necessary to resort to different treatment modalities prior to the rehabilitation(AU)

Application of Soft Relining Materials in Dental Medicine - Clinical Results.

AIM: The objective of this study was to carry out an in vivo investigation of patients wearing dentures relined with soft materials, assuming their positive and negative alterations in time. MATERIALS AND METHODS: A direct survey method was used to gather data from 23 patients included in this study (11 male and 12 female patients). Twenty-seven dentures were made (12 partial and 15 total dentures) 9 of which in chairside procedures, 11 - in a laboratory, and 7 were made using the direct-indirect method. Patients were included in regular follow-ups at one month and six months, and at one, two, and three years after dentures delivery. The study started in 2014 and continued till 2017. RESULTS AND DISCUSSION: All participants completed questionnaires which included questions related to changes in retention and stability of the relined dentures, changes in color and softness, in bond strength, and inflammation. CONCLUSION: There were no significant differences in the behavior of the different groups of materials at six months. After six months we observed decline in the bond strength of the vinyl-polysiloxane (VPS) materials, as well as increased staining and hardness in the poly-methyl-methacrylate (PMMA).

Bond strength of hard direct reline materials to heat-cured acrylic denture base after immersion in denture cleansers.

BACKGROUND: Immersion-type denture cleansers are commonly used for denture hygiene maintenance. Hence, it is crucial to investigate the effect of denture cleansing solutions on bond strength between direct reline materials and denture base resin. AIMS: This in vitro study aimed to determine the effect of denture cleansers on bond strength between direct hard reline materials and denture base resin. MATERIALS AND METHODS: Cylindrical columns of hard-liners (Hard GC Reline, TDV Cold Liner Rebase, Tokuyama Rebase II Fast) were bonded to heat-polymerized denture base resin. A total of fifty specimens were fabricated for each reline material and divided into five groups (n = 10): Group I (control): No solution was used; Group II: Specimens were stored in distilled water for 60 days; Groups III, IV, and V: Specimens were stored in distilled water for 60 days with daily immersion in either sodium hypochlorite, calgon + sodium hypochlorite, or dentipur tablet for 5 min. The shear bond strength was examined at a cross-head speed of 1 mm/min. Failure mode was evaluated by stereomicroscope. STATISTICAL ANALYSIS: Data were analyzed by two-way ANOVA and Chi-square test (α=0.05). RESULTS: The results showed no significant interaction between the direct hard-liners and denture cleansers (P = 0.119). Hard GC Reline had the highest bond strength, followed by Tokuyama Rebase II Fast, and then, TDV Cold Liner Rebase. No significant difference existed in bond strength between samples immersed in water and cleansers or between the cleansers themselves. Hard GC Reline had more mixed failure mode compared to TDV Cold Liner Rebase and Tokuyama Rebase II Fast. There was a significant correlation between mixed mode of failure and higher values of bond strength (P = 0.008). CONCLUSIONS: Within the limitations of the present study, denture cleansing solutions could not significantly influence the bond strength between hard direct liners and denture base resin.

Effect of implant-supported mandibular overdentures versus reline on masticatory performance and salivary flow rates in very old adults-A randomized clinical trial.

PURPOSE: To compare the masticatory efficiency (ME), maximum voluntary bite force (MBF), masseter muscle thickness (MMT), and salivary flow rates (SFR) in completely edentulous dependent elders treated either with a conversion of their existing mandibular complete removable dental prostheses (CRDPs) into a two-implant overdenture (IOD) or a conventional reline of the CRDP. MATERIAL AND METHODS: Participants were randomly allocated into intervention (IG) and control (CG) groups. The IG received two implants in the mandibular canine regions, and their CRDPs were transformed into IODs. The CG received a conventional reline of their mandibular CRDPs. Outcomes were recorded at each recall visit (baseline, immediately, 3 months, 12 months after intervention, and subsequently on an annual basis). Statistical analyses used mixed linear regression models (level of significance: p < 0.05). RESULTS: The IG comprised 16 participants (age = 85.0 ± 6.2 years), while the CG comprised 16 (age = 84.8 ± 5.4 years), with a mean follow-up of 2.7 ± 2.2 years (range: 3 months-7 years). A significant increase of MBF in the IG was observed with an overall gain of 80 N (p < 0.001) compared with the reline group. There were no significant long-term changes in SFR, MMT, or ME within/between groups. CONCLUSION: Since dependent elders with mandibular IODs present a significant gain in MBF, but no relative increase in SFR, MMT, and ME, it seems that this increased capacity of MBF is not exploited by the elders during their habitual chewing.

The Effect of Food-Simulating Agents on the Bond Strength of Hard Chairside Reline Materials to Denture Base Resin.

PURPOSE: To investigate the influence of food-simulating agents on the shear bond strength between direct hard liners and denture base acrylic resin. In addition, mode of failure was evaluated. MATERIALS AND METHODS: One hundred fifty cylindrical columns of denture base resin were fabricated and bonded to three types of hard reline materials (Hard GC Reline, Tokuyama Rebase II Fast, TDV Cold Liner Rebase). Specimens of each reline material were divided into five groups (n = 10) to undergo 12-day immersion in distilled water, 0.02 N citric acid aqueous solution, heptane, and 40% ethanol/water solution at 37°C. The control group was not immersed in any solution. The shear bond strength test was performed, and the failure mode was determined. Statistics were analyzed with two-way ANOVA and chi-square test (α = 0.05). RESULTS: Significant interaction was found between the hard liners and food simulating agents (p < 0.001). The shear bond strength of Tokuyama in 40% ethanol and TDV in heptane decreased significantly (p = 0.001, p < 0.001 respectively); however, none of the solutions could significantly affect the shear bond strength of Hard GC Reline (p = 0.208). The mixed failure mode occurred more frequently in Hard GC Reline compared with the other liners (p < 0.001) and was predominant in specimens with higher bond strength values (p = 0.012). CONCLUSIONS: Food simulating agents did not adversely affect the shear bond strength of Hard GC Reline; however, ethanol and heptane decreased the bond strength of Tokuyama and TDV, respectively. These findings may provide support to dentists to recommend restricted consumption of some foods and beverages for patients who have to use dentures relined with certain hard liners.

Effects of relining materials on the flexural strength of relined thermoplastic denture base resins

PURPOSE: The aim of this study was to evaluate the effects of relining materials on the flexural strength of relined thermoplastic denture base resins (TDBRs). MATERIALS AND METHODS: For shear bond strength testing, 120 specimens were fabricated using four TDBRs (EstheShot-Bright, Acrytone, Valplast, Weldenz) that were bonded with three autopolymerizing denture relining resins (ADRRs: Vertex Self-Curing, Tokuyama Rebase, Ufi Gel Hard) with a bond area of 6.0 mm in diameter and were assigned to each group (n=10). For flexural strength testing, 120 specimens measuring 64.0×10.0×3.3 mm (ISO-1567:1999) were fabricated using four TDBRs and three ADRRs and were assigned to each group (n=10). The thickness of the specimens measured 2.0 mm of TDBR and 1.3 mm of ADRR. Forty specimens using four TDBRs and 30 specimens using ADRRs served as the control. All specimens were tested on a universal testing machine. For statistical analysis, Analysis of variance (ANOVA) with Tukey's test as post hoc and Spearman's correlation coefficient analysis (P=.05) were performed. RESULTS: Acry-Tone showed the highest shear bond strength, while Weldenz demonstrated the lowest bond strength between TDBR and ADRRs compared to other groups. EstheShot-Bright exhibited the highest flexural strength, while Weldenz showed the lowest flexural strength. Relined EstheShot-Bright demonstrated the highest flexural strength and relined Weldenz exhibited the lowest flexural strength (P < .05). Flexural strength of TDBRs (P=.001) and shear bond strength (P=.013) exhibited a positive correlation with the flexural strength of relined TDBRs. CONCLUSION: The flexural strength of relined TDBRs was affected by the flexural strength of the original denture base resins and bond strength between denture base resins and relining materials.

A combination technique for relining removable prostheses.

The two major types of resilient lining material include acrylic based lining material and silicone based lining material. Both these materials have few inherent disadvantages associated with them. A technique for overcoming the disadvantages of both the acrylic and silicone based lining materials by using them in a combination is presented in this article.

Patient-centered and clinical outcomes of mandibular overdentures retained with the locator system: A prospective observational study.

STATEMENT OF PROBLEM: Whether clinical or demographic variables affect the perception of treatment in terms of quality of life and satisfaction is unknown. PURPOSE: The purpose of this prospective study was to make an evidence-based assessment of the treatment outcomes (patient- and clinically based) of locator-retained mandibular overdentures. MATERIAL AND METHODS: This prospective observational study assessed patients with edentulism who had worn mandibular overdentures supported by 2 implants and retained by the locator system for at least 1 year of functional life (N=80). Medical histories were reviewed, and patients underwent oral examinations. Prosthetic clinical outcomes and patient well-being were registered using the Oral Health Impact Profile 20 (OHIP-20) and Oral Satisfaction Scale (OSS). RESULTS: Patient well-being scored an overall OHIP-20 score of 19.0 ±14.0 of 80 (the higher the score, the greater the impact and the worse the oral health-related quality of life); overall oral satisfaction was 8.3 ±1.7 of 10. Women suffered greater social impact (0.8 ±1.0) and disability (0.4 ±0.8) than men (0.4 ±0.7 versus 0.2 ±0.4, respectively). Impact on well-being was inversely proportional to both patient age and the age of the prosthesis (r=-0.25; P<.01). Implants had been placed on average 73.6 ±39.2 months previously, showing a survival rate of 82.5%. Most of the overdentures had been functioning for over 60 months. Relining (46.3%), readjustments (82.5%), and changes of nylon retention (1.5 ±1.8 per patient over 60 months of use) devices negatively influenced well-being. CONCLUSIONS: Mandibular overdentures produced good results with regard to quality of life and oral satisfaction, but attention should be paid to factors affecting clinical outcomes and patient well-being.

Utilização do laser de alta intensidade para aumento de retenção e estabilidade de prótese total removível ­ relato de caso / The utilization of high intensity laser to increase retention and stability of complete denture prosthesis ­ case report

A ausência de um adequado rebordo alveolar em pacientes desdentados é, de fato, um dos problemas que o profissional enfrenta para realização de uma prótese total bem retida. Em alguns casos, é necessária a realização de cirurgias pré-protéticas que preparem as bases ósseas e os tecidos moles para melhor retenção das próteses mucossuportadas. O objetivo deste trabalho é fazer um relato de caso de aprofundamento de vestíbulo como alternativa para melhorar a retenção e estabilidade de próteses totais removíveis. No relato de caso apresentado, trata-se de um paciente do sexo masculino, 79 anos de idade, portador uma prótese total superior com baixa retenção devido à extensa perda óssea adjacente. Ao examiná-lo clinicamente, observamos rebordos bastante reabsorvidos. Devido à falta de estabilidade e retenção da prótese, optou-se por realizar uma cirurgia para aprofundamento do vestíbulo, através da utilização do laser de alta intensidade. Estes lasers têm a capacidade de corte, vaporização, coagulação e descontaminação dos tecidos por ele irradiados. Proporcionam melhor campo operatório devido à hemostasia que promove, não necessita de sutura e sua reparação tecidual é mais rápida. Ao final do tratamento, obtivemos um aumento de rebordo ósseo considerável, proporcionando melhor retenção da prótese total (AU).

The absence of an adequate alveolar ridge in edentulous patients is indeed one of the problems faced by the professional to perform well retained dentures. In some cases, the completion of pre-prosthetic surgery I required in order to prepare the bone and soft tissues basis for better retention of the mucous supported prosthesis. The objective of this work is to report of vestibule deepening as an alternative to improve the retention and stability of removable dentures. This paper reports the case of a male patient, 79 years old, with upper prosthesis with low retention due to extensive adjacent bone loss. During clinical exam, considerable resorption of the ridge was observed. Due to the lack of stability and compromised retention of the prosthesis, we chose to perform surgery to deepen the hall, through the use of high intensity laser. These lasers have the ability to cut, vaporization, coagulation, and decontamination of irradiated tissues for it. They also provide better surgical field promoting hemostasis, do not require suturing, and tissue repair is faster. At the end of the treatment, we had a significant increase in bone edge, providing better retention of the denture (AU).

Erratum to: Application of addition-cured silicone denture relining materials to adjust mouthguards.

The purposes of this study were to examine the shock absorption capability of addition-cured silicone denture relining materials and the bonding strength of addition-cured silicone denture relining materials and a commercial mouthguard material to determine its applicability to mouthguard adjustment. Two addition-cured silicone denture relining materials were selected as test materials. The impact test was applied by a free-falling steel ball. On the other hand, bonding strength was determined by a delamination test. After prepared surface treatments using acrylic resin on MG sheet surface, 2 types of addition-cured silicone denture relining materials were glued to MG surface. The peak intensity, the time to peak intensity from the onset of the transmitted force and bonding strength were statistically analyzed using ANOVA and Tukey's honest significant difference post hoc test (p<0.05). These results suggest that the silicone denture relining materials could be clinically applicable as a mouthguard adjustment material.

Application of addition-cured silicone denture relining materials to adjust mouthguards.

The purposes of this study were to examine the shock absorption capability of addition-cured silicone denture relining materials and the bonding strength of addition-cured silicone denture relining materials and a commercial mouthguard material to determine its applicability to mouthguard adjustment. Two addition-cured silicone denture relining materials and eleven commercial mouthguard materials were selected as test materials. The impact test was applied by a free-falling steel ball. On the other hand, bonding strength was determined by a delamination test. After prepared surface treatments using acrylic resin on MG sheet surface, 2 types of addition-cured silicone denture relining materials were glued to MG surface. The peak intensity, the time to peak intensity from the onset of the transmitted force and bonding strength were statistically analyzed using ANOVA and Tukey's honest significant difference post hoc test (p<0.05). These results suggest that the silicone denture relining materials could be clinically applicable as a mouthguard adjustment material.

The Effect of Occlusal Splint Pretreatment on Mandibular Movements and Vertical Dimension of Occlusion in Long-Term Complete Denture Wearers.

PURPOSE: This study evaluated the pretreatment influence of occlusal splints and relines on mandibular movements (MM) and vertical dimension of occlusion (VDO) in longstanding complete denture wearers. MATERIALS AND METHODS: A total of 30 volunteers were randomly assigned to three groups (n = 10): control (C), relining of old denture (RD), and occlusal splints (OS). Individual extent of MM was assessed via intraoral Gothic arch tracings and the VDO using posed frontal images taken at three time points. RESULTS: The OS group showed statistically significant differences when compared with the other groups (P < .05). CONCLUSION: Both MM and VDO were significantly improved by use of occlusal splints pretreatment.

Effectiveness of chemical disinfection on biofilms of relined dentures: A randomized clinical trial.

PURPOSE: To evaluate the effect of disinfection with sodium perborate or chlorhexidine (when combined with brushing) on the removal of biofilm in relined dentures. METHODS: Swabs were collected 48 hours after the relining procedure and at the follow-up time intervals of 7, 15, 30, 90, and 180 days. The dentures' surface roughness was measured at the same times. 45 subjects were randomly divided into three groups of 15 subjects each. The control group brushed with coconut soap and a soft toothbrush. The sodium perborate group followed the same procedure and also disinfected with sodium perborate solution for 5 minutes per day. The chlorhexidine group followed the control group procedure and disinfected with 2% chlorhexidine digluconate solution for 5 minutes per day. The number of colony forming units and the surface roughness were evaluated statistically by 2-way repeated-measure ANOVA (α = 0.05). RESULTS: The control group dentures exhibited similar levels of microbial cells throughout the experiment. However, after 15 days, no microbial growth was observed on the dentures for which either disinfection agent was used. There were no statistically significant differences in superficial roughness between the groups (P = 0.298). The disinfection agents used, combined with brushing, were able to remove the relined dentures' biofilm after 15 days of disinfection. Roughness was not a predominant factor in CFU reduction.

Effect of incorporating antifungals on the water sorption and solubility of interim resilient liners for denture base relining.

STATEMENT OF PROBLEM: Incorporating antifungals into interim denture resilient liners has been proposed to prolong their clinical longevity and to treat denture stomatitis. However, information is lacking on the effect of this addition on water sorption and solubility. PURPOSE: The purpose of this in vitro study was to evaluate the addition of minimum inhibitory concentrations (MICs) of antifungals for Candida albicans biofilm on the water sorption (WS) and solubility of interim denture resilient liners. MATERIAL AND METHODS: Disk-shaped specimens (n=10; 50×0.5 mm) of tissue conditioner (Softone) and resilient liner (Trusoft) were created either without (control) or with the incorporation of 1 of the 3 following drugs at MICs (g of drug per g of resilient material powder): nystatin (Ny, 0.032g/g), chlorhexidine diacetate (Chx, 0.064g/g), and ketoconazole (Ke, 0.128g/g). Specimens were dried; immersed in water for 24 hours and 7 or 14 days; weighed, dried, and weighed again. Data (µg/mm(3)) were analyzed by 3-way ANOVA followed by the Tukey-Kramer honest significant differences test (α=.05). RESULTS: At the 14-day interval, only the addition of Chx (483.0 ±61.0 µg/mm(3)) increased the WS of the tissue conditioner compared with the control group (244.0 ±42.0 µg/mm(3); P<.001). For all periods, the solubility of both materials increased with the addition of Chx (27.7 ±6.1 µg/mm(3)) and Ke (30.9 ±5.3 µg/mm(3)) compared with the control group (22.5 ±6.0 µg/mm(3); P<.001). CONCLUSIONS: After 14 days, the addition of Ny and Ke at MICs in both Softone and Trusoft and addition of Chx in Trusoft did not affect WS. The solubility of the 2 interim materials was not altered by the addition of Ny for up to 14 days.

Surface treatment with methyl formate-methyl acetate increased the shear bond strength between reline resins and denture base resin.

BACKGROUND: Chemical surface treatment increases the shear bond strength (SBS) between hard reline resins (HRRs) and denture base resin. OBJECTIVE: To evaluate the effect of methyl formate-methyl acetate (MF-MA), when used as a surface treatment agent, on the SBS between denture base resin and different HRRs. MATERIALS AND METHODS: One hundred and twenty specimens of heat-polymerised acrylic resin denture base (Meliodent(®) ) were divided into 12 groups. These groups comprised denture base relined with three self-polymerised HRRs [Unifast trad(®) (UT), Tokuyama(®) RebaseII Fast (TR), Ufi gel hard(®) (UG)], and treated with their respective Bonding Agent (BA) or by MF:MA solutions at ratios of 35:65, 25:75, and 15:85 for 15 s. The SBS was measured using a Universal Testing Machine. The data were analysed using two-way anova and post hoc Tukey's analysis at p < 0.05. RESULTS: The highest SBS was in the UT treated with MF:MA at a ratio of 25:75 group, followed by UT treated with MF:MA at ratios of 15:85, 35:65, UT treated with BA, and all UG treated with MF:MA groups. The SBS of the UT treated with MF:MA at a ratio of 25:75 group was significantly higher than those of the groups treated with BA. The SBS of the UG treated with MF:MA groups was significantly higher than control. The TR groups treated with BA or MF:MA groups showed no significant difference in SBS. CONCLUSION: Surface treatment with MF-MA significantly enhanced the SBS of denture base resin and UT and UG compared to that of the groups treated with BA.

Three-Year Analysis of Fixed and Removable Telescopic Attachment-Retained Implant-Supported Dental Prostheses: Survival and Need for Maintenance.

PURPOSE: The purpose of this retrospective clinical study was to evaluate the clinical outcomes of fixed implant-supported dental prostheses (FISDPs) and removable ISDPs (RISDPs) retained by telescopic attachments, the factors influencing survival, and the type and number of maintenance treatments required during the observation period. MATERIALS AND METHODS: This retrospective clinical study is based on patients who were provided with ISDPs between 2004 and 2010. Patient sex, type of prosthesis, location, opposing dentition, and the effect of continuous follow-up on the probability of a favorable outcome, as well as the number of maintenance treatments, were analyzed. A statistical analysis was performed using the Kaplan-Meier method. RESULTS: A sample of 233 patients with 157 FISDPs and 76 RISDPs supported by a total of 567 implants was randomized and included in the analysis. The mean observation period was 15.9 ± 15.4 months (maximum, 66.0 months). During the observation period, 3.9% of prostheses (7/157 FISDPs and 2/76 RISDPs) ceased to function and 2.3% of implants (13 implants) were lost. The mean survival time was 59.7 ± 2.3 months, with a survival probability of 90.2% after 3 years. Prostheses in the mandible showed significantly higher survival rates than those in the maxilla. Maintenance treatments had to be performed at an earlier stage for patients with RISDPs than for patients with FISDPs. In patients with a conventional removable prosthesis in the opposing arch, the time until maintenance was needed was significantly shorter. CONCLUSION: Within the limitations of a retrospective study, it can be concluded that the FISDPs and RISDPs show equally good survival rates after 3 years in function. RISDPs showed a greater and earlier need for maintenance treatments during the first years in function.