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1.
Clin Exp Dent Res ; 9(6): 983-992, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-37786371

RESUMEN

OBJECTIVES: The aim of this in vitro study was to evaluate the effect of arch size and implant angulation on the accuracy of digital impression in two intraoral scanners of Trios (3shape) and CEREC (Omnicam). MATERIAL AND METHODS: Four acrylic models each including six implants at sites 11, 12, 15, 17, 23, and 27 were used, including large with parallel implants, large with angled implants, small with parallel implants, and small with angled implants. After tightening the scan bodies, distance measurements were done using a coordinate measuring machine. Then, each model was scanned 10 times using each scanner. Trueness and precision measurements were finally computed. RESULTS: The trueness values ranged from 20 to 260 µm in CEREC Omnicam, and from 40 to 1030 µm in Trios. The precision values ranged from 30 to 190 µm in CEREC Omnicam, while from 50 to 770 µm in Trios. The multivariate test analysis indicated that the measured distances via two scanners and different models show different behaviors. Pairwise interactions between these three variables were significant (p < .05). Pairwise interactions between these variables were also significant. (p < .0001). CONCLUSIONS: Arch width could affect the accuracy of digital impression; by rotating toward the second quadrant and end points of the scan, errors have increased. However, the angulation of the implants had no effect on the accuracy of digital impression. The CEREC Omnicam scanner showed higher accuracy (trueness and precision) compared to the Trios (3shape) one.


Asunto(s)
Implantes Dentales , Imagenología Tridimensional , Modelos Dentales , Diseño Asistido por Computadora , Técnica de Impresión Dental
2.
Front Dent ; 20: 21, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37701650

RESUMEN

Objectives: Professionalism is essential to a strong and trusted patient-doctor relationship, which is believed to potentially enhance patient compliance and treatment outcomes. The purpose of our study was to develop and conduct a psychometric analysis of an assessment tool to evaluate the professional behavior of dental students. Materials and Methods: The study was performed in the School of Dentistry, Tehran University of Medical Sciences. After providing a pool of various criteria to assess professionalism, an expert panel prepared the primary version of the tool. The tool was set in a questionnaire frame to explore the significance level and evaluation feasibility of each criterion. The questionnaire was completed by tutors of the "Medical Ethics" course (n=6). After necessary revisions, face and content validity were evaluated by giving the checklist to eight experienced dental educators to determine the relevance, clarity, and simplicity of the questions. In the second stage, the final checklist (37 items) was given to dental educators to evaluate twenty students. To assess the reliability of this checklist, at least two professors evaluated each student, and weighted-κ was calculated. Minor revisions were made based on the received feedback. Results: According to our data, the total validity of the tool (S-CVI) was 100%. For all items except one, the weighted-κ coefficient was ≥ 0.5, indicating sufficient reliability for these items. Conclusion: Despite the limitations of the present study, the designed tool to evaluate professionalism among dental students in different clinical departments seems to be both valid and reliable.

3.
Front Dent ; 19: 6, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35937144

RESUMEN

Objectives: This study aimed to assess the color change (∆E00) of 7 brands of denture teeth (conventional acrylic and composite teeth) following immersion in staining solutions. Materials and Methods: Maxillary central incisor denture teeth made of 4 conventional acrylic resins (Vitapan, SR Vivodent PE, Beta Star and Crystal) and 3 composite resins (Finex, Emeral and Phonares II) were randomly divided into four groups (n=5). Denture teeth of different brands were immersed in tea, coffee, cola, and turmeric solutions. The solutions were incubated at 37°C. The baseline color of the teeth was measured using an intraoral spectrophotometer. The color of the teeth was measured after 24 h (∆E12), 1 week (∆E13), 2 weeks (∆E14), and 1 month (∆E15). ∆E00 was calculated and analyzed using one-way ANOVA. Pairwise comparisons were performed by the Tukey's post-hoc test (P<0.05). Results: The color stability of all teeth was significantly affected by the solutions (P<0.001). The type of tooth and coloring solution had significant interactions at all times (P<0.05). Turmeric caused the maximum color change in all teeth after 1 month. Repeated measures ANOVA showed that ∆E00 of all teeth was significantly affected by the duration of immersion in the solutions (P<0.001). Conclusion: within the limitations of this study, 1-month immersion of denture teeth in coffee, tea and cola solution altered the ∆E values; however, they were within the acceptable range, except for Beta Star. Turmeric solution caused unacceptable color change in all denture teeth even after 24 h of immersion.

4.
J Clin Exp Dent ; 13(6): e572-e579, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34188763

RESUMEN

BACKGROUND: Limited information is available regarding the marginal adaptation of three-unit interim restorations fabricated by different techniques from different materials. Also, the efficacy of computer-aided design/computer-aided manufacturing (CAD-CAM) systems for their fabrication is still questionable. This study aimed to assess the marginal adaptation of three-unit interim restorations fabricated by the CAD-CAM systems and the direct method from different materials before and after thermocycling. MATERIAL AND METHODS: A sound mandibular second premolar and a second molar were prepared for a three-unit all-ceramic restoration. Metal dies were fabricated to simulate a case of mandibular first molar missing, and were mounted in an acrylic block. Seventy-two three-unit interim restorations were fabricated by different techniques from different materials in six groups (n=12). In the first four groups, restorations were fabricated from Tempron, Visalys Temp, Unifast III, and Acropars by the direct technique, while the Amann Girrbach and Arum CAD-CAM systems and Ceramill Temp blocks were used in the last two groups. Marginal gap in each group was measured under a stereomicroscope at ×100 magnification. The specimens then underwent 5000 thermal cycles (5-55°C), and the marginal gap was measured again afterwards. ANCOVA and Bonferroni test (for pairwise comparisons) were applied for statistical analyses (α=0.05). RESULTS: Amann Girrbach and Arum CAD-CAM systems were not significantly different regarding the marginal gap of restorations (P=0.999). Among the traditional interim materials, Acropars showed significantly higher marginal gap than others (P<0.001). No significant difference was noted between other traditional materials. CAD-CAM interim materials showed significantly smaller marginal gap than traditional materials (P<0.001). CONCLUSIONS: The CAD-CAM interim materials yielded superior marginal adaptation in three-unit interim restorations compared with traditional interim materials. The type of CAD-CAM system had no significant effect on the final marginal adaptation of restorations. Key words:Dental marginal adaptation, interim dental prosthesis, CAD-CAM.

5.
Int J Dent ; 2021: 7843979, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34987585

RESUMEN

OBJECTIVES: Despite the widespread use of resin cements in cementing dental restorations, their bond strength to CAD/CAM base metal alloys is not widely studied. This study aimed to evaluate the microshear bond strength (µSBS) between cobalt-chrome (Co-Cr) alloys fabricated using casting or CAD/CAM methods with three types of resin cements. MATERIALS AND METHODS: Fifty Co-Cr blocks were prepared with CAD/CAM or casting technique. Specimens were divided using primer or not and bonded to three types of resin cements: Panavia F2, RelyX Unicem, and Duo-Link. The differences between the mean µSBS values were analyzed using the two-way ANOVA test and Tukey analysis (α = 0.05). The mode of failure was evaluated using a stereomicroscope. In addition, the specimens were examined by scanning electron microscopy (SEM) based on two received signals: backscattered electrons (SEB) and secondary electrons (SEs). One intact alloy specimen in each group was analyzed by energy-dispersive X-ray spectroscopy (EDX). RESULTS: Most of the specimens in the no-primer group were prematurely debonded. Statistical analyses showed that the interaction between the alloy substrate and cement type was significant (p=0.001). The bond strength of Panavia F2 was significantly higher than Duo-Link in the CAD/CAM group (p=0.001). SEM evaluation confirmed the difference in grain structures, while EDX showed no remarkable difference in the chemical composition of the alloy substrates. CONCLUSION: Alloy fabrication technique may influence the bond strength of resin cements. In the CAD/CAM group, cement containing MDP molecules exhibited higher strength than the etch-and-rinse one.

6.
Dent Res J (Isfahan) ; 17(6): 439-446, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33889349

RESUMEN

BACKGROUND: High percentage of biomechanical complications such as screw loosening in dental implants can be related to implant-abutment (I/A) connection properties which affect the behavior of implant assembly against functional loads in the oral cavity. The aims of the present study were to compare the reverse torque values (RTVs) and failure loads of three abutment types with internal Morse taper connection. MATERIALS AND METHODS: In this experimental in vitro study, eighteen implants (4.5 mm × 10 mm bone level implants, Implantium, Dentium Co, Seoul, South Korea) were divided into three groups with different abutments: two-piece (TP) abutment, one-piece (OP) abutment, and screw abutment (SA), mounted in stainless-steel blocks according to ISO 14801. After completion the torque/detorque protocol, a compressive load (1 mm/min) was applied at 30° off-axis until failure. Mean reverse torque/tightening torque (RT/TT) values and failure loads were analyzed with one-way ANOVA test and Tukey's honest significant difference (α = 0.05). Failure modes were evaluated by radiography and stereomicroscopy. RESULTS: RT/TT values in the TP group were lower than those in other groups (P < 0.001). Highest failure loads were observed in SA group (P = 0.002). In radiographic evaluation, all specimens showed deformation in I/A interface. CONCLUSION: I/A connections with larger surface areas may lead to higher RTVs (e.g., OP and SA groups). Use of an additional screw and indexed area in TP group did not reduce the bending resistance under static loading.

7.
Cranio ; 37(6): 383-388, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-29602287

RESUMEN

Objective: This study sought to assess the clinical signs and subjective symptoms of TMD, including the occlusal condition. Methods: Recruited individuals included 123 patients (58 men, 65 women) aged 15 to 65 years (mean 38.6 years) who had been referred to the TMD department. Helkimo dysfunction, occlusal, and anamnestic indices were used to assess signs of TMD, occlusal condition, and symptoms, respectively. Relationships of occlusal factors with signs and symptoms of TMD were evaluated by Spearman's correlation test. Associations of TMD with sex and age distributions were assessed by Mann-Whitney and Spearman's test, respectively. Results: The prevalence of signs and symptoms was as high as 75%. Occlusal factors had significant associations with signs and symptoms of TMD. Conclusion: Prevalence of TMD in the study population was high, without preference for age or sex. Occlusal factors may play a role in the etiology of TMD.


Asunto(s)
Trastornos de la Articulación Temporomandibular , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Adulto Joven
8.
Restor Dent Endod ; 43(4): e40, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30483464

RESUMEN

OBJECTIVES: This study evaluated the microtensile bond strength (µTBS) of polymer-ceramic and indirect composite resin with 3 classes of resin cements. MATERIALS AND METHODS: Two computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated polymer-ceramics (Enamic [ENA; Vita] and Lava Ultimate [LAV; 3M ESPE]) and a laboratory indirect composite resin (Gradia [GRA; GC Corp.]) were equally divided into 6 groups (n = 18) with 3 classes of resin cements: Variolink N (VAR; Vivadent), RelyX U200 (RXU; 3M ESPE), and Panavia F2 (PAN; Kuraray). The µTBS values were compared between groups by 2-way analysis of variance and the post hoc Tamhane test (α = 0.05). RESULTS: Restorative materials and resin cements significantly influenced µTBS (p < 0.05). In the GRA group, the highest µTBS was found with RXU (27.40 ± 5.39 N) and the lowest with VAR (13.54 ± 6.04 N) (p < 0.05). Similar trends were observed in the ENA group. In the LAV group, the highest µTBS was observed with VAR (27.45 ± 5.84 N) and the lowest with PAN (10.67 ± 4.37 N) (p < 0.05). PAN had comparable results to those of ENA and GRA, whereas the µTBS values were significantly lower with LAV (p = 0.001). The highest bond strength of RXU was found with GRA (27.40 ± 5.39 N, p = 0.001). PAN showed the lowest µTBS with LAV (10.67 ± 4.37 N; p < 0.001). CONCLUSIONS: When applied according to the manufacturers' recommendations, the µTBS of polymer-ceramic CAD/CAM materials and indirect composites is influenced by the luting cements.

9.
J Dent (Tehran) ; 15(2): 97-105, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29971127

RESUMEN

OBJECTIVES: The aim of this study was to evaluate the retention strength of zirconia crowns luted with two types of resin cement under environmental pressure changes. MATERIALS AND METHODS: Thirty zirconia crowns were fabricated by using computer-aided design/computer-aided manufacturing (CAD/CAM) system and were cemented by Panavia F2.0 (PAN), hand-mixed RelyX Unicem (UNH), or auto-mix RelyX Unicem Aplicap (UNA) cements on the corresponding extracted human molars. The samples were randomly divided into three groups according to the cement type. After 3000 thermal cycles, the cemented crowns were subjected to 24 pressure cycles (0 to 5 atmospheres). The retention force (N) of the specimens was measured in a universal testing machine. To normalize the retentive force, the recorded force was divided by the surface area of each tooth for measuring the retentive strength (MPa). The mean retention strengths (and forces) of the groups were compared by using one-way analysis of variance (ANOVA) and Tukey's honest significant difference (HSD) test (α=0.05). The failure modes were also examined by using a stereomicroscope. RESULTS: The retention values related to the evaluated resin cements were significantly different; the UNA group showed the highest retention strength (6.45±0.35 MPa) followed by the UNH (4.99±0.47 MPa) and PAN (4.45±0.39 MPa, P<0.001) groups. The adhesive failure mode was predominant in all the groups. CONCLUSIONS: The choice of resin cements and their mixing methods, which lead to differences in porosity, may affect the retention strength of zirconia crowns.

10.
Int J Dent ; 2018: 1456745, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29849632

RESUMEN

PURPOSE: Porcelain laminate veneers (PLVs) are sometimes required to be used for teeth with composite fillings. This study examined the fracture strength of PLVs bonded to the teeth restored with different sizes of class V composite fillings. MATERIALS AND METHODS: Thirty-six maxillary central incisors were divided into three groups (n=12): intact teeth (control) and teeth with class V composite fillings of one-third or two-thirds of the crown height (small or large group, resp.). PLVs were made by using IPS e.max and bonded with a resin cement (RelyX Unicem). Fracture resistance (N) was measured after cyclic loading (1 × 106 cycles, 1.2 Hz). For statistical analyses, one-way ANOVA and Tukey test were used (α=0.05). RESULTS: There was a significant difference between the mean failure loads of the test groups (P=0.004), with the Tukey-HSD test showing lower failure loads in the large-composite group compared to the control (P=0.02) or small group (P=0.05). The control and small-composite groups achieved comparable results (P > 0.05). CONCLUSIONS: Failure loads of PLVs bonded to intact teeth and to teeth with small class V composite fillings were not significantly different. However, extensive composite fillings could compromise the bonding of PLVs.

11.
J Dent (Tehran) ; 14(2): 105-108, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29104602

RESUMEN

In completely edentulous patients, limited interarch distance can compromise conventional prosthetic fabrication. Bone reduction through various surgical procedures has been recommended to restore an acceptable interarch distance. In such circumstances, a surgical guide built on a mounted cast can be used to minimize and control the amount of bone reduction performed. In the present report, an innovative method of fabrication of surgical guide has been described.

12.
Eur J Prosthodont Restor Dent ; 25(2): 79-85, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28590093

RESUMEN

The purpose of this study was to compare the accuracy of zirconia FPDs fabricated by different laboratory CAD/CAM system. Thirty-six FPD zirconia frameworks were fabricated on corresponding epoxy resin models that were duplicated from a master model of mandibular second premolar and second molar mounted in an acrylic block to simulate missing first mandibular tooth. Frameworks were divided into groups (n = 12) of three laboratory CAD/CAM systems: Cercon, Amann Girrbach, and Zirkonzahn. For the two factors, system and abutment type, the absolute marginal discrepancy (AMD) was measured before cementation. Internal fit was also determined at three sites after cementation. The data were analyzed statistically (α = 0.05). The effects of system and tooth type were not significant for AMD (p ⟩ 0.05). Both factors showed influence on the internal fit of FPDs (p ⟨ 0.05). Molars showed larger gaps in axial and occlusal sites (p = 0.001 and p = 0.003), and Cercon led in better occlusal adaptation compared with Amann Girrbach (p = 0.013). The systems tested did not show differences in AMD, despite different incorporated components. However, internal fit was significantly different between tooth type and system.


Asunto(s)
Diseño Asistido por Computadora , Adaptación Marginal Dental , Materiales Dentales , Diseño de Dentadura , Dentadura Parcial Fija , Circonio , Humanos
13.
Eur J Prosthodont Restor Dent ; 23(2): 56-61, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26373198

RESUMEN

The aim of this study was to determine the effects of different storage media and bleaching treatments on the flexural strength of two resin cements (Panavia and BisCem). One hundred rectangular-shaped specimens were prepared with two resin cements and were stored in five media types (n = 10): distilled water (DW), lactic acid (LA), sodium hydroxide (NH), in-office bleaching (OB) and home bleaching (HB). There was significant interaction between the solutions and cements (p < 0.05). The lowest three-point flexural strength was found in sodium hydroxide for both cements (p < 0.05). Both cements exhibited significant increase in flexural strength following home and in-office bleaching (except Panavia in OB) (p < 0.05) compared with immersion in distilled water. Panavia recorded significantly higher flexural strength compared with BisCem in all media (p < 0.002), with the exception of in-office bleaching.


Asunto(s)
Cementos de Resina/química , Blanqueadores Dentales/química , Peróxido de Carbamida , Resinas Compuestas/química , Análisis del Estrés Dental/instrumentación , Humanos , Humedad , Peróxido de Hidrógeno/química , Ácido Láctico/química , Curación por Luz de Adhesivos Dentales/instrumentación , Ensayo de Materiales , Peróxidos/química , Docilidad , Polimerizacion , Hidróxido de Sodio/química , Estrés Mecánico , Temperatura , Factores de Tiempo , Urea/análogos & derivados , Urea/química , Agua/química
15.
J Dent (Tehran) ; 12(12): 874-81, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27559346

RESUMEN

OBJECTIVES: The purpose of this in vitro study was to compare the marginal adaptation and fracture resistance of a zirconia-based all-ceramic restoration with two preparation designs. MATERIALS AND METHODS: Twenty-four mandibular premolars were randomly divided into two groups (n=12); the conventional group received a peripheral shoulder preparation and the modified group received a buccal shoulder and proximal/lingual chamfer preparation. The marginal fit of the zirconia crowns (Cercon) was evaluated using a stereomicroscope. After cementation, load was applied to the crowns. The mean fracture load and the mean marginal gap for each group were analyzed using t-test (P=0.05). RESULTS: The mean marginal gap was 71±16µm in the conventional group and 80±10µm in the modified group, with no significant difference (P=0.161). The mean fracture strength was 830±153N for the conventional group and 775±125N for the modified group, with no significant difference (P=0.396). All but one fracture occurred in the veneering ceramic. CONCLUSION: Less aggressive preparation of proximal and lingual finish lines for the preservation of tooth structure in all-ceramic restorations does not adversely affect the marginal adaptation or fracture strength of the final restoration.

16.
J Adv Prosthodont ; 6(4): 278-84, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25177471

RESUMEN

PURPOSE: There is insufficient data regarding the durability of porcelain laminate veneers bonded to existing composite fillings. The aim of the present study was to evaluate the fracture resistance and microleakage of porcelain laminate veneers bonded to teeth with existing composite fillings. MATERIALS AND METHODS: Thirty maxillary central incisors were divided into three groups (for each group, n=10): intact teeth (NP), teeth with class III composite fillings (C3) and teeth with class IV cavities (C4). Porcelain laminate veneers were made using IPS-Empress ceramic and bonded with Panavia F2 resin cement. The microleakage of all of the specimens was tested before and after cyclic loading (1 × 10(6) cycles, 1.2 Hz). The fracture resistance values (N) were measured using a universal testing machine, and the mode of failure was also examined. The statistical analyses were performed using one-way ANOVA and Tukey post hoc tests (α=.05). RESULTS: There was a significant difference in the mean microleakage of group C4 compared with group NT (P=.013). There was no significant difference in the fracture loads among the groups. CONCLUSION: The microleakage and failure loads of porcelain laminate veneers bonded to intact teeth and teeth with standard class III composite fillings were not significantly different.

17.
J Indian Prosthodont Soc ; 14(Suppl 1): 31-6, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26199489

RESUMEN

Several treatments have been suggested to improve the retention of zirconia-based restorations luted with different cements. Resin cements are believed to improve crown retention under certain circumstances. The aim of the present study was to examine the effect of three cements with different mixing methods on the retention of CAD/CAM zirconia crowns. Thirty extracted human molars were randomly divided into three groups and prepared for all-ceramic crowns (6° taper, 4-mm height and a 1.2 mm rounded shoulder finish line). A zirconia crown (Tizian CAD/CAM) was fabricated for each tooth. The crowns were air-abraded using airborne particles, adjusted, and cemented to the corresponding tooth with one of the following cements: Panavia F2 (PAN group), RelyX Unicem (UNH group) or RelyX Unicem Aplicap (UNA group). After 3,000 rounds of thermal cycling, retention was measured using a specific retentive jig and a universal testing machine. The retention strength was measured by dividing the retention force by the surface area of each tooth. The means of the pull-out test results for each group were compared using analysis of variance and Tukey's HSD test (α = 0.05). The mode of failure was examined using a stereomicroscope. The mean retention value was 6.45 (0.34) MPa for the UNA group, 4.99 MPa (0.47) for the UNH group, and 4.45 (0.39) for the PAN group; the differences among the three test groups were significant. A mixed failure was observed in 83.3 % of specimens, while no cohesive failure occurred in the crowns. Within the limitations of the present study, of the three tested cements, Relyx Unicem Aplicap cement was associated with the highest retention force for Tizian zirconia crowns.

18.
J Dent (Tehran) ; 10(1): 94-102, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23724207

RESUMEN

OBJECTIVE: The effects of closely adapting a prefabricated fiber to the post space remain unknown. The purpose of this study was to quantify the microleakages of a custom adapted fiber-reinforced post, a prefabricated quartz fiber post and a cast post using nondestructive methods. MATERIALS AND METHODS: Sixty-five extracted human premolars were endodontically treated and randomly divided into three groups (n=15), which were restored using a cast post-and-core, a custom adapted fiber post (Refropost) with a microhybrid microfiller resin composite (Gradia), or a prefabricated quartz fiber post (DT light post) and two groups of control (n=10). All groups were cemented using a dual polymerizing resin cement (Panavia F2.0). A composite core (Z100) was used for the fiber posts. The microleakage was calculated for the experimental and control groups before and after thermal cycling and cycling loading using a radiotracer solution (thallium 201 chloride) and a gamma counter device. Data were subjected to statistical analysis of ANOVA and Tukey HSD at significant level of P< 0.05. RESULTS: Significantly lower microleakage values were found for the cast post-and-core (mean value =16.04 ×10(4)) and custom adapted fiber post groups (mean value=14.36×10(4)). Thermal cycling and cyclic loading had no significant effect on the microleakage value of any tested group. CONCLUSION: Post systems with improved adaptation showed similar microleakage to casting posts.

20.
Arch. oral res. (Impr.) ; 7(1): 17-26, jan.-abr. 2011. ilus, tab
Artículo en Inglés | LILACS, BBO - Odontología | ID: lil-667648

RESUMEN

Objective: The purpose of this study was to compare the microleakage of four cements in cast post-andcoresystems under cyclic loading. Materials and methods: Sixty-four human premolars were sectionedat the cement-enamel junction, endodontically treated, and divided into four groups (n = 16). Cast postsand cores were fabricated for root segments and were cemented with zinc phosphate cement (Harvard),resin-modified glass ionomer (Fuji PLUS), dual-cured phosphate methacrylate resin cement (Panavia F),or a dual-cured resin cement (Variolink II). All specimens underwent thermal cycling for 1.500 cycleswith 5 °C and 55 °C, with a dwelling time of 12 seconds. Half of the specimens of each group were subjectedto cycling loading with 50 N at 1.2 Hz for 750,000 cycles. Specimens were then immersed in 5%basic fuchsin solution for 24 hours. Specimens were sectioned, visualized by stereomicroscope under40x magnification and scored for dye penetration. The ratio between the length of the interface and thelength of dye penetration was also determined. Microleakage differences between the four cements were analyzed by Kruskal-Wallis test, and the effect of fatigue was analyzed with Mann-Whitney nonparametrictest (α =.05). Results: No failures occurred during fatigue testing. The zinc phosphate cement showedsignificantly higher microleakage values compared to other cements under both unloaded and loadedconditions (p = .007 and p = .006). Fatigue significantly increased the microleakage in all groups (p < .05).Conclusions: The microleakage values for the resin cements and the resin-modified glass ionomer weresimilar and significantly less than those of zinc phosphate, irrespective of loading. Fatigue loading increasedthe microleakage values for all the cements.


Objetivo: O objetivo deste estudo foi comparar a microinfiltração de pinos e núcleos de preenchimento metálicoscimentados com quatro diferentes materiais. Materiais e Métodos: 64 pré-molares humanos foram seccionadosna junção cemento-esmalte, tratados endodonticamente e divididos em quatro grupos (n = 16). Pinos enúcleos metálicos fundidos foram fabricados e cimentados com cimento de fosfato de zinco (Harvard), cimentode ionômero de vidro modificado (Fuji Plus), cimento resinoso dual de metacrilato fosfato (Panavia F) e cimentoresinoso dual (Variolink II). Todos os espécimes foram submetidos à ciclagem térmica (1.500 ciclos a 5-55 °C, 12segundos de banho). Metade dos espécimes de cada grupo foi submetida a uma carga cíclica de 50 N a 1,2 Hz emum total de 750.000 ciclos. Após a ciclagem, os espécimes foram imersos em solução de fucsina básica 5% por24 horas, seccionados, visualizados sob aumento de 40x e ranqueados quanto à penetração do corante. A proporçãoentre o comprimento da interface e o comprimento da penetração do corante foi também determinada.As diferenças de infiltração entre os quatro cimentos foram analisadas por teste de Kruskal-Wallis e o efeito dafadiga foi analisado por teste não paramétrico de Mann-Whitney (α = 0,05). Resultados: Não ocorreram falhasdurante o teste de fadiga. O cimento de fosfato de zinco mostrou valores de infiltração significativamente maiorescomparados aos demais cimentos na ausência ou presença da fadiga (p = 0,007 e p = 0,006). A fadiga elevousignificativamente a microinfiltração em todos os grupos (p < 0,05). Conclusões: Os valores de microinfiltraçãopara os cimentos resinosos e para o cimento de ionômero de vidro modificado foram similares e inferiores àquelesdo cimento de fosfato de zinco, independente da aplicação do teste de fadiga. A fadiga elevou os valores de microinfiltraçãopara todos os cimentos.


Asunto(s)
Humanos , Cementos Dentales/química , Filtración Dental , Pins Dentales , Análisis del Estrés Dental , Técnicas In Vitro , Técnica de Perno Muñón , Ensayo de Materiales , Estadísticas no Paramétricas , Propiedades de Superficie , Factores de Tiempo
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