Comparative study of interim materials for direct fixed dental prostheses and their fabrication with CAD/CAM technique.

STATEMENT OF PROBLEM: Prosthodontic treatment sometimes requires a long-term interim fixed dental prosthesis (FDP) until the definitive restoration can be cemented. However, some interim materials are weak and do not have an adequate marginal seal. PURPOSE: The purpose of this study was to compare the marginal fit and fracture strengths of interim FDPs fabricated by using a direct technique with different materials (Structur 3, Trim, and DuraLay) with interim prostheses (Telio CAD) made with a computer-aided design and computer-aided manufacturing (CAD/CAM) system. MATERIAL AND METHODS: Seventy interim FDPs were fabricated by using different materials (Structur 3, Trim, DuraLay, and Telio CAD) on a metal master model. Resin-impregnated, light-polymerizing glass fiber (GrandTEC) was used to reinforce 10 interim FDPs per material fabricated with the direct technique. Interim FDPs were stored at 37°C for 24 hours before thermocycling. Marginal fit was analyzed at 6 points in each interim FDP before and after thermocycling with either 2500 or 5000 cycles. After fracturing the interim FDPs with a universal testing machine, fracture strength, fragments separation, and fracture point were recorded. Marginal fit data were analyzed with 2-way repeated measure analysis of variance (ANOVA), fracture strength with 1-way ANOVA, and fragments separation and fracture point with the chi-square test at a 99% confidence interval. RESULTS: All interim materials showed marginal discrepancies over time, but no significant differences were found among groups (P>.001), except in the marginal fit of interim FDPs reinforced with glass fiber (S3F), which showed the smallest marginal gap after 5000 cycles (P<.001). Reinforced interim FDPs (S3F, TMF, and DLF) and CAD/CAM FDPs (TCC) presented a fracture strength ranging between 471.3 ±62.4 N and 531.1 ±150.1 N (P>.001). Finally, significant differences were observed in the fracture point and frequency of separation (P<.001). CONCLUSIONS: Bis-acryl reinforced with glass fiber showed the least marginal discrepancy. No differences were found between the fracture strengths of interim FDPs fabricated with CAD/CAM system and interim FDPs reinforced with glass fiber. No significant difference in fracture strength was observed between interim FDPs reinforced with glass fiber and prostheses fabricated with CAD/CAM system. However, unreinforced interim FDPs showed the lowest fracture strength.

Color stability of white mineral trioxide aggregate.

OBJECTIVE: This study aims to evaluate the color stability of white mineral trioxide aggregate (WMTA) after irradiation with three different curing lights and with a fluorescent lamp in an oxygen-free environment. MATERIAL AND METHODS: Thirty samples of WMTA were divided into four experimental groups (three curing light and one fluorescent lamp) and one negative control group. The samples in the curing light groups were immersed in glycerine and were irradiated for 20, 60, and 120 s with a curing light. The samples in the fluorescent lamp group were immersed in glycerine and left on a laboratory shelf below a fluorescent lamp, whereas the negative control group was irradiated with a curing light without immersion in glycerine. A spectrophotometer was used to determine the color of each specimen before and after each light exposure and after 5 days. Data were analyzed using analysis of variance and Fisher's least significant difference test. RESULTS: All the groups showed discoloration except for the negative control group. At 20, 60, and 120 s, there were no significant differences between the Optilux and Bluephase groups (which were the darkest). The Demi group was the curing light experimental group that showed the lowest degree of discoloration (P = 0.0001). No differences were observed between the fluorescent lamp and the negative control groups. After 5 days, the fluorescent lamp group also showed darkening of the sample surface and there were no significant differences between this group and the other three experimental groups (P > 0.05). CONCLUSIONS: WMTA showed dark discoloration after irradiation with a curing light or fluorescent lamp in an oxygen-free environment. CLINICAL RELEVANCE: WMTA may cause tooth discoloration when it is used in a coronal position.

Color stability of siloranes versus methacrylate-based composites after immersion in staining solutions.

OBJECTIVES: The purpose of this study was to determine, by using a spectrophotometer device, the color stability of silorane in comparison with four methacrylate-based composites after being immersed in different staining solutions such as coffee, black tea, red wine, orange juice, and coke, and distilled water as control group. METHODS: Four restorative methacrylate-based composites (Filtek Z250, TetricEvoCeram, Venus Diamond, and Grandio) and one silorane (FiltekSilorane) of shade A2 were selected to measure their color stability (180 disk samples) after 4 weeks of immersion in six staining solutions: black tea, coffee, red wine, orange juice, coke, and distilled water. The specimen's color was measured each week by means of a spectrophotometer (CIE L*a*b* system). Statistical analysis was carried out performing an ANOVA and LSD Test in order to statistically analyze differences in L*a*b*and ∆E values. RESULTS: All materials showed significant discoloration (p < 0.05) when compared to the control group (immersed in distilled water). The Highest ∆E observed was with red wine, whereas coke led to the lowest one. Silorane showed the highest color stability compared with methacrylate-based composites. CONCLUSIONS: Methacrylate-based materials immersed in staining solutions showed lower color stability when compared with silorane. Great differences in ∆E were found among the methacrylate-based materials tested. CLINICAL RELEVANCE: Although color stability of methacrylate-based composites immersed in staining solutions has been widely investigated, this has not been done for long immersion periods with silorane-based composites.

Six-month color change and water sorption of 9 new-generation flowable composites in 6 staining solutions.

Color match and water sorption are two factors that affect restorative materials. Discoloration is essential in the lifespan of restorations. The aim of this study was to evaluate color change and water sorption of nine flowable composites at multiple time points over 6 months. 60 samples of each composite were divided into two groups (Color Change and Water Sorption/Solubility). Each Color Change group was divided into six subgroups, which were immersed in distilled water (DW), coffee (CF), Coca-Cola (CC), red wine (RW), tea (TE) and orange juice (OJ). The color was measured at the baseline, 1, 2, 3 and 4 weeks, and 3 and 6 months and color change values (ΔE) were calculated. Each Water Sorption [WS]/Solubility [WL] group was tested according to ISO 4049:2009. The data were evaluated using two-way ANOVA, Fisher's post-hoc test and Pearson's correlation test. The composite with the lowest ΔE differed for each solution: Filtek™ Bulk Fill in DW (∆E = 0.73 (0.17-1.759)); Vertise Flow in CF (∆E = 14.75 (7.91-27.41)), in TE (∆E = 7.27 (2.81-24.81)) and OJ (∆E = 3.17 (0.87-9.92)); Tetric EvoFlow® in CC (∆E = 1.27 (0.45-4.02)); and Filtek™ Supreme XTE in RW (∆E = 8.88 (5.23-19.59)). RW caused the most discoloration (∆E = 23.62 (4.93-51.36)). Vertise Flow showed the highest water sorption (WS = 69.10 ± 7.19). The Pearson test showed statistically significant positive correlations between water sorption and solubility and between water sorption and ∆E; the positive solubility-∆E correlation was not statistically significant. The findings suggest that water sorption is one factor associated with the ability of composites to discolor; however, discoloration is a multifactorial problem.

Color Stability of Teeth Restored with Biodentine: A 6-month In Vitro Study.

INTRODUCTION: White mineral trioxide aggregate (WMTA) has been reported to cause dental discoloration. A previous study on the color stability of 5 calcium silicate-based materials investigated the color stability of Biodentine (Septodont, Saint-Maur-des-Fossés, France) in different experimental environments; however, no data are available on the color stability of teeth restored with Biodentine. In this study, we assessed the color stability under artificial light of ex vivo human teeth restored coronally with WMTA or Biodentine. METHODS: Cavities were prepared on coronal tooth specimens and restored with WMTA + composite (n = 16), Biodentine + composite (n = 16), or composite alone (control, n = 3). Color was assessed spectrophotometrically at 6 time points (initial, 1 week, 2 weeks, 1 month, 3 months, and 6 months), and color difference values were calculated. Statistical analysis was performed using analysis of variance and the Fisher least significant difference test for which P < .05 was considered statistically significant. RESULTS: The WMTA group showed discoloration at 1 week, which increased over time. The Biodentine and control groups showed color stability and were not significantly different from one another. CONCLUSIONS: Teeth treated with WMTA exhibited discoloration, whereas those treated with Biodentine maintained color stability throughout the study. However, further in vivo studies are necessary to corroborate these results.

Efficacy of Reciproc(®) and Profile(®) Instruments in the Removal of Gutta-Percha from Straight and Curved Root Canals ex Vivo.

OBJECTIVES: To compare the efficacy of Reciproc(®) (VDW GmbH) and ProFile(®) (Dentsply Maillefer) instruments at removing gutta-percha from straight and curved root canals ex vivo filled using the cold lateral condensation and GuttaMaster(®) (VDW GmbH) techniques. MATERIAL AND METHODS: Forty mesial roots of mandibular molars with two curved canals and 80 single-rooted teeth with straight root canals, a total of 160 root canals, were randomly assigned to eight groups (canals per group = 20) according to filling technique, retreatment instrument and root canal curvature as follows: Group I, cold lateral condensation/ProFile(®)/straight; Group II, cold lateral condensation/ProFile(®)/curved; Group III, cold lateral condensation/Reciproc(®)/straight; Group IV, cold lateral condensation/Reciproc(®)/curved; Group V, GuttaMaster(®)/ProFile(®)/straight; Group VI, GuttaMaster(®)/ProFile(®)/curved; Group VII, GuttaMaster(®)/Reciproc(®)/straight; and Group VIII, GuttaMaster(®)/Reciproc(®)/curved. The following data were recorded: procedural errors, retreatment duration and canal wall cleanliness. Means and standard deviations were calculated and analysed using the Kruskal-Wallis test, one-way analysis of variance and Tukey's test (P < 0.05). RESULTS: Reciproc(®) instruments were significantly faster than ProFile(®) instruments at removing GuttaMaster(®) from both straight (P = 0.0001) and curved (P = 0.0003) root canals. Reciproc(®) were statistically more effective than ProFile(®) instruments in removing GuttaMaster(®) from straight root canals (P = 0.021). Regardless of filling technique or retreatment instrument, gutta-percha was removed more rapidly from curved than from straight root canals (P = 0.0001). CONCLUSIONS: Neither system completely removed filling material from the root canals. Compared with ProFile(®) instruments, Reciproc(®) instruments removed GuttaMaster(®) filling material from straight and curved root canals more rapidly.

Six-month color change and water sorption of 9 new-generation flowable composites in 6 staining solutions

Abstract Color match and water sorption are two factors that affect restorative materials. Discoloration is essential in the lifespan of restorations. The aim of this study was to evaluate color change and water sorption of nine flowable composites at multiple time points over 6 months. 60 samples of each composite were divided into two groups (Color Change and Water Sorption/Solubility). Each Color Change group was divided into six subgroups, which were immersed in distilled water (DW), coffee (CF), Coca-Cola (CC), red wine (RW), tea (TE) and orange juice (OJ). The color was measured at the baseline, 1, 2, 3 and 4 weeks, and 3 and 6 months and color change values (ΔE) were calculated. Each Water Sorption [WS]/Solubility [WL] group was tested according to ISO 4049:2009. The data were evaluated using two-way ANOVA, Fisher's post-hoc test and Pearson's correlation test. The composite with the lowest ΔE differed for each solution: Filtek™ Bulk Fill in DW (∆E = 0.73 (0.17-1.759)); Vertise Flow in CF (∆E = 14.75 (7.91-27.41)), in TE (∆E = 7.27 (2.81-24.81)) and OJ (∆E = 3.17 (0.87-9.92)); Tetric EvoFlow® in CC (∆E = 1.27 (0.45-4.02)); and Filtek™ Supreme XTE in RW (∆E = 8.88 (5.23-19.59)). RW caused the most discoloration (∆E = 23.62 (4.93-51.36)). Vertise Flow showed the highest water sorption (WS = 69.10 ± 7.19). The Pearson test showed statistically significant positive correlations between water sorption and solubility and between water sorption and ∆E; the positive solubility-∆E correlation was not statistically significant. The findings suggest that water sorption is one factor associated with the ability of composites to discolor; however, discoloration is a multifactorial problem.

An evaluation of root ZX and iPex apex locators: an in vivo study.

INTRODUCTION: iPex is a fourth-generation apex locator (EAL) that has not yet been tested in vivo. The purpose of this study was to compare the accuracy of the Root ZX (J Morita Corp, Tokyo, Japan) and iPex (NSK, Tochigi, Japan) EALs. METHODS: The working length (WL) was determined electronically for 40 root canals of human teeth with a K-file and one of the two EALs. The files were fixed at the WL, and the teeth were extracted. The apical 4 mm of each canal was trimmed to expose the file tip. The samples were observed under a scanning electron microscope, and the distance from the file tip to the point 0.5 mm coronal to the major foramen (the actual WL) was measured. The data were analyzed using the Mann-Whitney U test, and significance was set at P < .05. RESULTS: No statistically significant differences were found between the Root ZX and iPex devices. The mean distance from the actual WL to the file tip was 0.146 ± 0.43 mm for the Root ZX and 0.128 ± 0.49 mm for the iPex. In determining the actual WL, the Root ZX was accurate 72% of the time to ± 0.5 mm and 100% of the time to ± 1 mm, whereas the iPex was accurate 57.8% of the time to ± 0.5 mm and 100% of the time to ± 1 mm. CONCLUSIONS: Under the in vivo clinical conditions of this study, no statistically significant differences were observed between the Root ZX and iPex EALs.

Análise de diagnósticos radiográfico periapicais sugestivos de lesões refratárias / Analysis of periapical radiographic diagnosis that suggest persistent lesion

Cicatrizes fibrosas periapicais podem ter aspecto radiográfico semelhante a lesões periapicais, levando ao plano de tratamento incorreto. Assim, o objetivo deste estudo foi realizar um confronto entre o diagnóstico radiográfico e histopatológico de dentes que foram tratados endodonticamente e apresentaram“lesões periapicais” detectadas radiograficamente após 18 meses do tratamento. Dez pacientes submetidos ao tratamento endodôntico adequado e apresentando imagem radiolúcia persistente 18 meses pós-tratamento, tiveram cirurgia paraendodôntica indicada. Durante a cirurgia, o tecido em volta do ápice foi removido e mergulhado em solução de formalina 10% para processamento histopatológico através de coloração de HE. O ápice removido na apicectomia foi mantido em glutaraldeído 2% e processado para análise por microscopia eletrônica de varredura. Dentre os 10 casos sugestivos de lesão periapical, em apenas um caso foi confirmado diagnóstico de cisto, um caso de granuloma, e os outros oito casos confirmaram cicatriz fibrosa. Em nenhum dos casos foi detectada a presença de bactéria extrarradicular, somente infiltrado inflamatório e presença de células de defesa como linfócitos e neutrófilos, além de hemácias, tecido conjuntivo e colágeno. Pode-se concluir que a radiográfica convencional não constitui ponto conclusivo no diagnóstico de lesões periapicais.

Periapical fibrous scars may have similar radiographic appearance of periapical lesions that canresult in incorrect diagnosis. The aim of this study was a confrontation between the radiographic and histopathologic diagnosis of teeth that were endodontically treated and presented “persistent periapical lesions” detected radiographically after 18 months of treatment. Ten patients under going adequate endodontic treatment and presenting persistent radiolucent image at 18 months post-treatment, had surgery Para endodontic indicated. During surgery, the tissue around the apex was removed and immersedin 10% formalin solution for histological processing by HE staining. The apex oh the tooth was removed and immersed in 2% glutaral dehyde for scanning electron microscopy processing. Among the 10 radiographically suggestive cases of persistent periapical lesion, only 1 case was confirmed diagnosis of cyst, 1 case of granuloma, and the other 8 cases were fibrous scar. In neither case was observed the presence of bacteria, only inflammatory infiltrate and the presence of defense cells such as lymphocytes and neutrophils, red blood cells, connective tissue and collagen. It can be concluded that the conventional radiography is not conclusive point in the diagnosis of periapical lesions.

Manejo conservador no quirúrgico de una reabsorción cervical invasiva tipo IV utilizando Biodentine / Nonsurgical conservative management of a class IV invasive cervical resorption using Biodentine

La reabsorción cervical invasiva (RCI) es una entidad poco frecuente de carácter agresivo que causa la destrucción de los tejidos dentales si no se trata. El diagnóstico de la RCI es complejo y de acuerdo a la literatura presente, en estadíos muy avanzados el tratamiento no es predecible, lo que conlleva la extracción del diente. Actualmente, gracias al avance de nuevas tecnologías para el radiodiagnóstico como la tomografía computerizada de haz cónico (CBCT), el microscopio dental, así como la introducción de nuevos materiales como el Agregado Trióxido Mineral (MTA(R)) el enfoque de este tratamiento y el pronóstico en estos casos puede mejorar. Recientemente, se ha introducido el Biodentine(R), un cemento biocerámico, como material sustitutivo del MTA(R) con claras ventajas sobre este como un menor tiempo de fraguado, que no presenta discoloración y unas propiedades mecánicas similares a la dentina. A continuación se presenta un caso de reabsorción cervical invasiva tratada con Biodentine® con controles clínicos, radiográficos y mediante CBCT a 6 meses

Invasive cervical resorption (ICR) is an uncommon but aggresive entity that cause the destruction of dental tissues if left untreaten. The diagnosis of ICR is complex and according to the literature, the treatment in advanced cases is not predictable, which can ultimately lead to extraction of the tooth. The current development of innovative technologies such as the cone-beam computed tomography (CBCT) and the dental operating microscope, as well as new materials such as mineral trioxide aggregate (MTA(R)) can facilitate improvements in the treatment approach and the prognosis of ICR. Recently, BiodentineTM, a new bioceramic cement, has been introduced as a substitutive material for MTA(R) with several advantages related to setting time, the elimination of discoloration and similar mechanic properties as dentine. A case of ICR is presented in which the management of the lesion using Biodentine is reported along with the clinical, radiographic and 6-month CBCT follow-up