Development of a fiber-reinforced material for fiber posts: Evaluation of stress distribution, fracture load, and failure mode of restored roots.

STATEMENT OF PROBLEM: The biomechanical behavior of post-restored roots with an experimental fiber-reinforced composite resin is unknown. PURPOSE: The purpose of this in vitro study was to investigate the biomechanical behavior of an experimental composite resin (3-mm short glass fiber incorporated in methacrylate matrix with filler particles) used to produce the custom post itself or to reline fiber posts. MATERIAL AND METHODS: Four testing groups (n=10) were created according to the root restoration method: FG, commercially available fiber post; FG+RC, fiber post relined with conventional composite resin; FG+EXP, fiber post relined with the experimental composite resin; and EXP, a custom post made of experimental composite resin. A three-dimensional finite element linear elastic analysis was performed by using geometric representations of groups, and the results were analyzed by von Mises (σvM) and maximum principal stress criteria. In sequence, 40 bovine incisors were assigned to these groups and subjected to a fracture load test (Instron 5965; 0.5 mm/min), and the failure mode was determined. RESULTS: The EXP group showed more homogeneous stress distribution for σvM. ANOVA and the Tukey honestly significant difference (HSD) tests showed significant differences (P<.001) in fracture load (mean ±standard deviation; different superscript letters indicate statistical difference): FG+EXP (669.5 ±107.7)A; FG (620.7 ±59.2)A; EXP (506.5 ±27.0)B; FG+RC (452.7 ±81.6)B. No differences were found for failure mode (P=.595). CONCLUSIONS: The experimental composite resin significantly increases fracture load when used to reline commercially available fiber posts and, irrespective of its use, presented lower stress concentration.

Influence of preheating and post-curing on a novel fiber-reinforced composite post material.

The aim of this study was to investigate the influence of preheating and post-curing methods on diametral tensile strength (DTS), flexural strength (FS), knoop microhardness (KHN), and degree of conversion (DC) of an experimental fiber-reinforced composite (FRC). Specimens (30 wt% of 3-mm-short E-glass fiber, 22.5 wt% of methacrylated-based resin and 47.5 wt% of filler particles) were subjected to: P - photocuring at 1500 mW/cm2 for 40 s (control); P/M - photocuring and microwave post-curing (540W/5 minutes); P/A - photocuring and autoclave post-curing (120°C/15 minutes); PH-P - preheating (60°C) and photocuring; PH-P/M - preheating, photocuring and microwave post-curing; and PH-P/A - preheating, photocuring and autoclave post-curing. Specimens for DTS (Ø 3 x 6 mm) and FS (25 x 2 x 2 mm) were tested at Instron 5965. KHN employed a 50g load for 30s. DC was measured using FTIR spectroscopy. Statistical analysis employed: factorial analysis, normality test, one-way ANOVA and Tukey's HSD test, independent T-test and the Dunnett test. Interaction between factors was not significant (P>0.05). Preheating promoted significantly higher values of FS and KHN (p = 0.0001). Post-curing promoted significantly higher values for KHN (p = 0.0001). For DTS (p = 0.066) and DC (p= 0.724) no statistical difference was found between groups. SEM images showed that preheating promoted better interaction between glass fibers and resin matrix. Preheating increased FS, KHN and DTS, and post-curing increased KHN. DC was not affected by both methods. Preheating and post-curing methods can be used to improve some mechanical properties of FRCs' but degree of conversion remains unaffected.

Influence of voxel size on cone-beam computed tomography-based detection of vertical root fractures in the presence of intracanal metallic posts.

PURPOSE: This study was performed to evaluate the influence of voxel size and the accuracy of 2 cone-beam computed tomography (CBCT) systems in the detection of vertical root fracture (VRF) in the presence of intracanal metallic posts. MATERIALS AND METHODS: Thirty uniradicular extracted human teeth were selected and randomly divided into 2 groups (VRF group, n=15; and control group, n=15). The VRFs were induced by an Instron machine, and metallic posts were placed in both groups. The scans were acquired by CBCT with 4 different voxel sizes: 0.1 mm and 0.16 mm (for the Eagle 3D V-Beam system) and 0.125 mm and 0.2 mm (for the i-CAT system) (protocols 1, 2, 3, and 4, respectively). Interobserver and intraobserver agreement was assessed using the Cohen kappa test. Sensitivity and specificity were evaluated and receiver operating characteristic analysis was performed. RESULTS: The intraobserver coefficients indicated good (0.71) to very good (0.83) agreement, and the interobserver coefficients indicated moderate (0.57) to very good (0.80) agreement. In respect to the relationship between sensitivity and specificity, a statistically significant difference was found between protocols 1 (positive predictive value: 0.710, negative predictive value: 0.724) and 3 (positive predictive value: 0.727, negative predictive value: 0.632) (P<.05). The least interference due to artifact formation was observed using protocol 2. CONCLUSION: Protocols with a smaller voxel size and field of view seemed to favor the detection of VRF in teeth with intracanal metallic posts.

Influence of preheating and post-curing on a novel fiber-reinforced composite post material

Abstract The aim of this study was to investigate the influence of preheating and post-curing methods on diametral tensile strength (DTS), flexural strength (FS), knoop microhardness (KHN), and degree of conversion (DC) of an experimental fiber-reinforced composite (FRC). Specimens (30 wt% of 3-mm-short E-glass fiber, 22.5 wt% of methacrylated-based resin and 47.5 wt% of filler particles) were subjected to: P - photocuring at 1500 mW/cm2 for 40 s (control); P/M - photocuring and microwave post-curing (540W/5 minutes); P/A - photocuring and autoclave post-curing (120°C/15 minutes); PH-P - preheating (60°C) and photocuring; PH-P/M - preheating, photocuring and microwave post-curing; and PH-P/A - preheating, photocuring and autoclave post-curing. Specimens for DTS (Ø 3 x 6 mm) and FS (25 x 2 x 2 mm) were tested at Instron 5965. KHN employed a 50g load for 30s. DC was measured using FTIR spectroscopy. Statistical analysis employed: factorial analysis, normality test, one-way ANOVA and Tukey's HSD test, independent T-test and the Dunnett test. Interaction between factors was not significant (P>0.05). Preheating promoted significantly higher values of FS and KHN (p = 0.0001). Post-curing promoted significantly higher values for KHN (p = 0.0001). For DTS (p = 0.066) and DC (p= 0.724) no statistical difference was found between groups. SEM images showed that preheating promoted better interaction between glass fibers and resin matrix. Preheating increased FS, KHN and DTS, and post-curing increased KHN. DC was not affected by both methods. Preheating and post-curing methods can be used to improve some mechanical properties of FRCs' but degree of conversion remains unaffected.

Effect of short glass fiber/filler particle proportion on flexural and diametral tensile strength of a novel fiber-reinforced composite.

PURPOSE: To evaluate the effect of glass fiber/filler particles proportion on flexural strength and diametral tensile strength of an experimental fiber-reinforced composite. METHODS: Four experimental groups (N=10) were created using an experimental short fiber-reinforced composite, having as a factor under study the glass fiber (F) and filler particle (P) proportion: F22.5/P55 with 22.5 wt% of fiber and 55 wt% of filler particles; F25/P52.5 with 25 wt% of fiber and 52.5 wt% of filler particles; F27.5/P50 with 27.5 wt% of fiber and 50 wt% of filler particles; F30/P47.5 with 30 wt% of fiber and 47.5 wt% of filler particles. The experimental composite was made up by a methacrylate-based resin (50% Bis-GMA and 50% TEGDMA). Specimens were prepared for Flexural Strength (FS) (25 mm × 2 mm × 2 mm) and for Diametral Tensile Strength (DTS) (3×6 Ø mm) and tested at 0.5 mm/min in a universal testing machine. RESULTS: The results (in MPa) showed significance (different superscript letters mean statistical significant difference) for FS (p<0.009) and DTS (p<0.001)--FS results: F22.5/P55: 217.24±20.64(B); F25/P52.5: 245.77±26.80(AB); F27.5/P50: 246.88±32.28(AB); F30/P47.5: 259.91±26.01(A). DTS results: F22.5/P55: 21.82±4.42(B); F25/P52.5: 22.00±7.40(B); F27.5/P50: 18.63±4.41(B); F30/P47.5: 31.05±2.97(A). In SEM analysis, areas without fiber reinforcement demonstrated to be more prone to the presence of bubbles and crack development. The group F30/P47.5 showed areas with a great quantity of fibers without empty spaces for crack propagation. CONCLUSION: Increasing fiber content results in higher flexural and diametral tensile strength of an experimental composite reinforced with glass fibers.

Perception of the signs and symptoms of temporomandibular disorder in females by using the ProTMDMulti protocol and the visual analog scale before and after acupuncture treatment.

OBJECTIVE: To evaluate the perceptions of patients with TMD in relation to the signs and symptoms before and after acupuncture treatment, according to the ProTMDMulti and the VAS. METHOD: 68 patients were divided into groups: muscle TMD treated with acupuncture at local points (MUS-LP), muscle TMD with acupuncture at distant points (MUS-DP), joint and muscle treated with LP (JOI-LP) and joint and muscle treated with DP (JOI-DP). The evaluations were performed at four times: initial, control, final and follow-up. RESULTS: The best results were seen in the JOI-LP and the MUS-DP groups, in which the perceptions of the signs and symptoms were statistically lower in the final assessment than in the initial (P<0.05). In all groups, the final and the follow-up evaluations were similar. CONCLUSIONS: For TMDs with joint components, the best acupuncture treatment involves local points and for the TMDs with muscle components, points at a distance.

The influence of polymerization type and reinforcement method on flexural strength of acrylic resin.

The aim of this study was to evaluate the flexural strength of acrylic resin bars by varying the types of resin polymerization and reinforcement methods. Fourteen groups (N=10) were created by the interaction of factors in study: type of resin (self-cured (SC) or heat-cured (HC)) and reinforcement method (industrialized glass fiber (Ind), unidirectional glass fiber (Uni), short glass fiber (Short), unidirectional and short glass fiber (Uni-Short), thermoplastic resin fiber (Tpl), and steel wire (SW)). Reinforced bars (25×2×2 mm) were tested in flexural strength (0.5 mm/min) and examined by scanning electron microscopy (SEM). Data (MPa) were submitted to factorial analysis, ANOVA, and Tukey and T-student tests (a=5%) showing significant interaction (P=0.008), for SC: Uni (241.71±67.77)a, Uni-Short (221.05±71.97)a, Ind (215.21±46.59)ab, SW (190.51±31.49)abc, Short (156.31±28.76)bcd, Tpl (132.51±20.21)cd, Control SC (101.47±19.79)d and for HC: Ind (268.93±105.65)a, Uni (215.14±67.60)ab, Short (198.44±95.27)abc, Uni-Short (189.56±92.27)abc, Tpl (161.32±62.51)cd, SW (106.69±28.70)cd, and Control HC (93.39±39.61)d. SEM analysis showed better fiber-resin interaction for HC. Nonimpregnated fibers, irrespective of their length, tend to improve fracture strength of acrylics.

Influence of the powder/liquid ratio and storage time of conventional glass ionomer cements in diametral tensile strength

Introduction: The Glass Ionomer Cements (GICs) are the most versatile dental material with extensive clinical indication. However, the mechanical strength of conventional GICs (C-GICs) is still unsatisfactory under areas of masticatory forces. Objective: To evaluate the influence of C-GIC proportioning system (powder-liquid and encapsulated) and storage period (1h, 24h and 7 days) on Diametral Tensile Strength (DTS). Material and methods: The two variables were tested in relation to C-GIC (Riva Self Cure, SDI, Australia). The following proportioning systems were tested: powder-liquid by weight (g:g) and powder-liquid by volume (flat scoop: drop) and encapsulated system (pre-dosed capsules). Five C-GIC specimens were prepared, according to ISO specification #9917 for each variable to be studied. The specimens were stored in plastic containers containing distilled water and kept at 37ºC and 100% humidity until the mechanical testing in a universal testing machine (Instron Corp., USA) at a speed 0.5 mm/min. The data were submitted to two-way ANOVA and Tukey test for multiple comparisons (α = 0.05). Results: The proportioning system (P < 0.0001) and storage time (P < 0.0001) were significant predictors of DTS, however with no interaction between these factors. Conclusion: The DTS of C-GICs was influenced by storage time (1 hour < 24 hours < 7 days) and by the proportioning system only for the initial period of its setting reaction.

Effect of glass fiber incorporation on flexural properties of experimental composites.

This study evaluated the effect of fiber addiction in flexural properties of 30 wt% silica filled BisGMA resin (FR) or unfilled Bis-GMA (UR). Ten groups were created (N = 10) varying the resin (FR or UR) and quantity of glass fibers (wt%: 0, 10, 15, 20, and 30). Samples (10 × 2 × 1 mm) were submitted to flexural strength test following SEM examination. Data were analyzed by two-way ANOVA, Tukey, and Student t-test (α = 0.05). Results for flexural strength (MPa) were FR-groups: 0% (442.7 ± 140.6)(C), 10% (772.8 ± 446.3)(ABC), 15% (854.7 ± 297.3)(AB), 20% (863.4 ± 418.0)(A), 30% (459.5 ± 140.5)(BC); UR-groups: 0% (187.7 ± 120.3)(B), 10% (795.4 ± 688.1)(B), 15% (1999.9 ± 1258.6)(A), 20% (1911.5 ± 596.8)(A), and 30% (2090.6 ± 656.7)(A), and for flexural modulus (GPa) FR-groups: 0% (2065.63 ± 882.15)(B), 10% (4479.06 ± 3019.82)(AB), 15% (5694.89 ± 2790.3)(A), 20% (6042.11 ± 3392.13)(A), and 30% (2495.67 ± 1345.86)(B); UR-groups: 0% (1090.08 ± 708.81)(C), 10% (7032.13 ± 7864.53)(BC), 15% (19331.57 ± 16759.12)(AB), 20% (15726.03 ± 8035.09)(AB), and 30% (29364.37 ± 13928.96)(A). Fiber addiction in BisGMA resin increases flexural properties, and the interaction between resin and fibers seems better in the absence of inorganic fillers increasing flexural properties.

Reinforcement of dental methacrylate with glass fiber after heated silane application.

This study evaluated the influence of silane heat treatment and glass fiber fabrication type, industrially treated (I) or pure (P), on flexural and compressive strength of methacrylate resin bars (BISGMA/TEGDMA, 50/50%). Six groups (n = 10) were created: I-sil: I/silanated; P-sil: P-silanated; I-sil/heat: I/silanated heated to 100°; P-sil/heat: P/silanated heated to 100°; (I: I/not silanated; and P: P/not silanated. Specimens were prepared for flexural strength (10 × 2 × 1 mm) and for compressive strength 9.5 × 5.5 × 3 mm) and tested at 0.5 mm/min. Statistical analysis demonstrated the following for flexural strength (P < 0.05): I-sil: 155.89 ± 45.27(BC); P-sil: 155.89 ± 45.27(BC); I-sil/heat: 130.20 ± 22.11(C); P-sil/heat: 169.86 ± 50.29(AB); I: 131.87 ± 15.86(C). For compressive strength, the following are demonstrated: I-sil: 1367.25 ± 188.77(ab); P-sil: 867.61 ± 102.76(d); I-sil/heat: 1162.98 ± 222.07(c); P-sil/heat: 1499.35 ± 339.06(a); and I: 1245.78 ± 211.16(bc). Due to the impossibility of incorporating the stipulated amount of fiber, P group was excluded. Glass fiber treatment with heated silane enhanced flexural and compressive strength of a reinforced dental methacrylate.

Influence of activation mode of resin cement on the shade of porcelain veneers.

PURPOSE: The aim of this study was to evaluate the influence of resin luting cement's activation mode in the final shade of porcelain veneers after accelerated artificial aging (AAA). MATERIALS AND METHODS: Porcelain veneers (IPS Empress Esthetic) were produced using a standardized shade (ET1) and thickness (0.6 mm). Twenty bovine teeth were collected, prepared, and divided into two groups: group I (n = 10)-light-cured group, only base paste was applied to the veneers; group II (n = 10)-dual-cured group, in which the same base paste used in group I and a transparent catalyst were proportionally mixed for 20 seconds and then applied to the veneers. The specimens were light-cured for 60 seconds each and were next subjected to AAA. They were submitted to color readings with a spectrophotometer in three instances: in the tooth surface (only the substrate), after the cementation and polymerization of the veneers, and after the AAA. The values of L*, a*, and b* were obtained and the total color change was calculated (∆E*). Values obtained were subjected to statistical analysis, with a significance of 0.05. RESULTS: There were no significant differences between dual- and light-cured modes considering ∆E*, L*, a*, and b* values obtained after aging (p > 0.05). Within the dual-cured mode there were no significant differences in ∆E*, L*, a*, and b* values (p > 0.05). CONCLUSION: No relevant differences were found between the two activation modes in color change. When submitted to aging, dual- and light-cured modes of the resin cement showed visually perceptible (∆E* > 1.0) color changes; however, within the threshold of clinical acceptance (∆E* > 3.3).

Comparação entre enxerto autógeno e xenógeno no levantamento do seio maxilar: relato de caso clínico com dois anos de acompanhamento clínico e por tomografia computadorizada de feixe cônico / Comparison between intra-oral autogenous and one xenogeneic bone source for maxillary sinus lifting: a case report with 2-year follow-up clinical and CBCT results

O objetivo deste trabalho foi analisar, por meio de imagens radiológicas, a regeneração óssea nas regiões posteriores de maxila atrófica após procedimento de levantamento de seio maxilar com utilização, em diferentes sítios cirúrgicos, de enxerto ósseo autógeno e enxerto ósseo xenógeno (Bio-Oss). No procedimento cirúrgico, a região anterior foi enxertada com osso autógeno em bloco, proveniente do ramo mandibular direito; o seio esquerdo foi levantado com osso autógeno proveniente do ramo mandibular esquerdo; e o seio direito foi preenchido com osso xenógeno (Bio-Oss). Posteriormente, foram instalados os implantes e a prótese tipo protocolo após osseointegração. Após acompanhamento de dois anos, verificou-se aumento da densidade óssea nos sítios enxertados, bem como estabilização dos implantes em harmonia com a prótese.

The aim of this paper was to analyze through radiological images the bone regeneration at posterior atrophic maxillary regions after sinus lifting in different surgical sites using autogenous and xenogeneic bone grafts (Bio-Oss). On surgery, the anterior region was grafted with block autogenous bone from the right mandibular ramus; the left sinus was lifted with autogenous material from the left mandibular ramus; and the right sinus area received a xenogeneic material. After, dental implants were placed and a fixed total prosthesis was delivered after the osseointegration period. The 2-year follow-up images demonstrated an increase on the density at the grafted sites, as well as implant stability and adequate prosthetic integration.

Técnica de estratificação e texturização superficial de resinas compostas em dentes anteriores: seis meses de acompanhamento / Layering technique and surface texturization of composite resins in anterior teeth: six month follow-up

Este relato de caso apresenta uma alternativa conservadora para reanatomização de dentes conóides e fechamento de diastemas. O método escolhido foi uma técnica restauradora adesiva direta com resinas compostas, estratificada com diferentes camadas e cores, e posterior texturização superficial durante as fases de acabamento e polimento finais. As restaurações resultaram em dentes reanatomizados, reproduzindo naturalidade de forma, textura e cor, mantidas pelos seis meses em que a paciente foi acompanhada. Com planejamento adequado, enceramento diagnóstico e estratificação-texturização com resinas compostas, foi possível restabelecer o sorriso com proporções, forma e naturalidade satisfatórias.

This report presents an alternative, conservative treatment for reshaping conoid teeth and diastema closure. The chosen method was a direct restorative technique with composite resins, stratified with different masses and shades, and subsequent surface texturization during the final stages of finishing and polishing. The final restorations reproduced naturally the form, texture and shade, followed-up for 6 months. After proper planning, diagnostic wax-up and stratification/surface texturization of composite resins reestablished the smile with pleasant proportions, shape and life-like appearance of the smile

Effect of light sources and curing mode techniques on sorption, solubility and biaxial flexural strength of a composite resin.

UNLABELLED: Adequate polymerization plays an important role on the longevity of the composite resin restorations. OBJECTIVES: The aim of this study was to evaluate the effect of light-curing units, curing mode techniques and storage media on sorption, solubility and biaxial flexural strength (BFS) of a composite resin. MATERIAL AND METHODS: Two hundred and forty specimens were made of one composite resin (Esthet-X) in a stainless steel mold (2 mm x 8 mm Ø), and divided into 24 groups (n=10) established according to the 4 study factors: light-curing units: quartz tungsten halogen (QTH) lamp and light-emitting diodes (LED); energy densities: 16 J/cm² and 20 J/cm²; curing modes: conventional (CM) and pulse-delay (PD); and permeants: deionized water and 75% ethanol for 28 days. Sorption and solubility tests were performed according to ISO 4049:2000 specifications. All specimens were then tested for BFS according to ASTM F394-78 specification. Data were analyzed by three-way ANOVA followed by Tukey, Kruskal-Wallis and Mann-Whitney tests (α=0.05). RESULTS: In general, no significant differences were found regarding sorption, solubility or BFS means for the light-curing units and curing modes (p>0.05). Only LED unit using 16 J/cm² and PD using 10 s produced higher sorption and solubility values than QTH. Otherwise, using CM (16 J/cm²), LED produced lower values of BFS than QTH (p<0.05). 75% ethanol permeant produced higher values of sorption and solubility and lower values of BFS than water (p<0.05). CONCLUSION: Ethanol storage media produced more damage on composite resin than water. In general the LED and QTH curing units using 16 and 20 J/cm² by CM and PD curing modes produced no influence on the sorption, solubility or BFS of the tested resin.

Longevidade de clareamento em dente não vital com associação de técnicas: relato de caso / Longevity of nonvital tooth bleaching with a combination of techniques. Case report

O clareamento dentário, por ser um tratamento não invasivo e de baixo custo, representa uma excelente opção de tratamento para dentes com alteração cromática. O propósito desse artigo é relatar um caso clínico com associação de técnicas de clareamento para dentes não vitais e discutir as implicações clínicas imediatas e mediatas. Paciente do sexo masculino, 30 anos de idade, procurou o serviço odontológico da Universidade Estadual de Londrina para tratamento estético do dente 21, diagnosticado com escurecimento após traumatismo e tratamento endodôntico. Diante do exame radiográfco, que não mostrou alterações da normalidade, foi instituído o clareamento dentário intracoronário com pasta clareadora de perborato de sódio e peróxido de hidrogênio a 20% (6 sessões, com intervalo de 7 dias), seguido por clareamento intra- e extracoronário com peróxido de hidrogênio a 35% (3 sessões de 20 minutos ininterruptos, com intervalo de 7 dias). Passados 10 dias da última sessão de clareamento, foi confeccionada restauração da face palatina com resina composta. Também foi feito controle clínico e radiográfco após 18 meses. O resultado obtido demonstrou a longevidade do procedimento realizado. Assim,conclui-se que o clareamento de dentes não vitais é seguro,efcaz e, quando necessário, pode ser realizado com diferentes produtos, aplicados por diferentes técnicas.

Tooth bleaching, as a non-invasive and low cost treatment,provides an excellent option for teeth with color change. The purpose of this study is to report a case with a combination of techniques for nonvital teeth bleaching and discuss the immediate and mediate clinical implications. Male patient,30 year-old, came to the dental service at the State University of Londrina for esthetic treatment of tooth #21, diagnosed with severe darkening after trauma accentuated by endodontic treatment. Radiographic examination showed no alterations of normality. It was established a treatment with intracoronal bleaching techniques, using sodium perborate with 20% hydrogen peroxide (6 sessions every 7 days), followed by intra- and extracoronal bleaching with 35% hydrogen peroxide (3 sessions of 20 minutes every 7 days). Restoration with composite resin for the fnal sealing of the cavity was made 10 days after the end of bleaching. Clinical and radiographic control after 18 months also were performed.The result showed the longevity of the procedure. Therefore it can be conclude that the nonvital bleaching is safe, effective and can be performed with different products, applied by different techniques

Effect of light sources and curing mode techniques on sorption, solubility and biaxial flexural strength of a composite resin

Adequate polymerization plays an important role on the longevity of the composite resin restorations. OBJECTIVES: The aim of this study was to evaluate the effect of light-curing units, curing mode techniques and storage media on sorption, solubility and biaxial flexural strength (BFS) of a composite resin. MATERIAL AND METHODS: Two hundred and forty specimens were made of one composite resin (Esthet-X) in a stainless steel mold (2 mm x 8 mm Ø), and divided into 24 groups (n=10) established according to the 4 study factors: light-curing units: quartz tungsten halogen (QTH) lamp and light-emitting diodes (LED); energy densities: 16 J/cm² and 20 J/cm²; curing modes: conventional (CM) and pulse-delay (PD); and permeants: deionized water and 75% ethanol for 28 days. Sorption and solubility tests were performed according to ISO 4049:2000 specifications. All specimens were then tested for BFS according to ASTM F394-78 specification. Data were analyzed by three-way ANOVA followed by Tukey, Kruskal-Wallis and Mann-Whitney tests (α=0.05). RESULTS: In general, no significant differences were found regarding sorption, solubility or BFS means for the light-curing units and curing modes (p>0.05). Only LED unit using 16 J/cm² and PD using 10 s produced higher sorption and solubility values than QTH. Otherwise, using CM (16 J/cm²), LED produced lower values of BFS than QTH (p<0.05). 75% ethanol permeant produced higher values of sorption and solubility and lower values of BFS than water (p<0.05). CONCLUSION: Ethanol storage media produced more damage on composite resin than water. In general the LED and QTH curing units using 16 and 20 J/cm² by CM and PD curing modes produced no influence on the sorption, solubility or BFS of the tested resin.

Rehabilitation of periodontally compromised teeth with fiber-reinforced composite resin: a case report.

The rehabilitation of prosthetic spaces resulting from severe periodontitis represents a challenge in terms of functional and esthetic aspects. Generally, tooth extraction is followed by alveolar ridge volume reduction, which increases the esthetic problem. The aim of this article is to report the integration of esthetics and functional parameters in the oral rehabilitation of extracted periodontally compromised mandibular central incisors through the construction of a direct glass fiber-reinforced composite fixed partial denture (DFPD). After periodontal therapy, the patient received a periodontal subepithelial graft, enabling an increase in the thickness and height of the alveolar ridge. The DFPD was fabricated with the use of extracted teeth. Mandibular canines and lateral incisors received cavities 2 mm deep and wide. After fiber insertion, tooth adaptation, and composite resin coverage, the teeth were finished and polished. Results showed an excellent esthetic result with stabilization and function of the remaining periodontally affected teeth.

Pinos de fibra anatômicos: técnica clínica e benefícios mecânicos — relato de caso

Introdução: o emprego de pinos estéticos compostos por fibra de vidro tem sido cada vez mais estudado e os benefícios biomecânicos, além da possibilidade adesiva,tornam viável seu uso em várias situações clínicas. Estudos mostram que a perfeita adaptação às paredes do canal radicular é importante para melhorar as propriedades do conjunto dente-pino. Objetivo: apresentar a sequência técnica de um reembasamento de pino de fibra de vidro em canal amplo de um incisivo central fraturado coronalmente. Relato do caso: paciente do sexo masculino,12 anos de idade, apresentou-se com fratura oblíqua no dente 11 após acidente, atingindo a câmara pulpar.Após tratamento endodôntico, a obturação do canal radicular foi removida em preparo mecânico, resultando em necessidade de reembasamento do pino de fibra (Exacto#3, Angelus), que foi realizado com resina composta microhíbrida (Natural Look, DFL). O pino foi cimentado com adesivo convencional de três passos quimicamente polimerizado (Fusion Duralink, Angelus) e cimento resinoso autopolimeriável (Cement Post, Angelus), sendo posteriormente reconstruída a restauração da fratura dentária. Resultados: alcançou-se ótima resolução funcional e estética, com previsão de grande durabilidade clínica

Influence of powder/liquid ratio on the radiodensity and diametral tensile strength of glass ionomer cements

Clinicians tend to make reductions in glass ionomer power/liquid (P/L) ratios since some materials are difficult to mix and flow into small cavities, grooves or pits. In general, changing the P/L ratio decreases the physical and mechanical properties of conventional glass ionomer cements (GICs) and resin modified glass ionomer cements (RMGICs), but alterations seem to depend on their composition. OBJECTIVE: To determine the influence of P/L ratio on the radiodensity and diametral tensile strength (DTS) of glass ionomer cements. MATERIAL AND METHODS: There were 2 factors under study: P/L ratio (manufacturer's recommended P/L ratio and a 50 percent reduced P/L ratio), and materials (Vitro Molar, Vitro Fil, Vitro Cem conventional GICs and Vitro Fil LC, Ortho Glass LC RMGICs. Five 1-mm-thick samples of each material-P/L ratio were produced for radiodensity evaluation. Samples were x-ray exposed onto Digora phosphor plate and radiodensity was obtained using the software Digora for Windows 2.5 Rev 0. For DTS, five (4.0x8.0 mm) cylinder samples of each material were tested (0.5 mm/min). Data were subjected to one- and two-way ANOVA (5x2) followed by Tukey's HSD test, or Kruskal-Wallis and Dunn's method. For paired comparisons, t-test or Mann-Whitney test were used (α=0.05). RESULTS: There was a significant interaction (P=0.001) for the studied factors (materials vs. P/L ratio). Reduced P/L ratio resulted in significantly lower DTS for the RMGICs, but radiodensity was affected for all materials (P<0.05). CONCLUSIONS: Reduced P/L ratio affected properties of the tested glass ionomer cements. RMGICs were more susceptible to lower values of DTS, but radiodensity decreased for all materials following P/L ratio reduction.

Radiodensity evaluation of dental impression materials in comparison to tooth structures.

UNLABELLED: In the most recent decades, several developments have been made on impression materials' composition, but there are very few radiodensity studies in the literature. It is expected that an acceptable degree of radiodensity would enable the detection of small fragments left inside gingival sulcus or root canals. OBJECTIVE: The aim of this study was to determine the radiodensity of different impression materials, and to compare them to human and bovine enamel and dentin. MATERIAL AND METHODS: Twenty-five impression materials, from 5 classes, were studied: addition and condensation silicones, polyether, polysulfides and alginates. Five 1-mm-thick samples of each material and tooth structure were produced. Each sample was evaluated 3 times (N=15), being exposed to x-ray over a phosphor plate of Digora digital system, and radiodensity was obtained by the software Digora for Windows 2.5 Rev 0. An aluminum stepwedge served as a control. Data were subjected to Kruskal-Wallis and Dunn's method (α=0.05). RESULTS: Different materials and respective classes had a different behavior with respect to radiodensity. Polysulfides showed high values of radiodensity, comparable to human enamel (p>0.05), but not to bovine enamel (p<0.05). Human dentin was similar only to a heavy-body addition silicon material, but bovine dentin was similar to several materials. Generally, heavy-body materials showed higher radiodensity than light-body ones (p<0.05). CONCLUSION: Impression materials' radiodensity are influenced by composition, and almost all of them would present a difficult detection against enamel or dentin background in radiographic examinations.