ABSTRACT
Abstract Objective To assess pulp oxygen saturation levels (SaO2) in maxillary central incisors after dental bleaching. Materials and Methods 80 participants (160 teeth) were randomly allocated to four groups: G1 In-office bleaching with two applications of 35% hydrogen peroxide (HP) (20 minutes), followed by at-home bleaching with 10% carbamide peroxide (CP) (2 hours/day for 16 days); G2 - Same protocol as G1, plus desensitizing toothpaste; G3 - In-office bleaching with 35% HP and one application of placebo gel (20 minutes), followed by at-home bleaching with 10% CP (2 hours/day for 16 days); and G4 - Same protocol as G3, plus desensitizing toothpaste. Pulp SaO2 levels were measured before (T0) and immediately after (T1) in-office bleaching; on the 5th (T2), 8th (T3), 12th (T4), and 16th days of at-home bleaching (T5); and on the 7th (T6) and 30th (T7) days. Mean (SD) pulp SaO2 levels were compared within groups by generalized estimating equations (GEE) and Student's t-test (P<0.05). Results Mean pulp SaO2 at T0 was 84.29% in G1, 84.38% in G2, 84.79% in G3, and 85.83% in G4. At T1, these values decreased to 81.96%, 82.06%, 82.19%, and 81.15% in G1, G2, G3, and G4 respectively, with significant difference in G4 (P<0.05). During home bleaching, pulp SaO2 levels varied in all groups, with 86.55%, 86.60%, 85.71%, and 87.15% means at T7 for G1, G2, G3, and G4, respectively; G2 presented significant difference (P<0.05). Conclusions Pulp SaO2 level in maxillary central incisors was similar at baseline, reducing immediately after in-office bleaching, regardless of using desensitizing toothpaste and increasing at 30 days after dental bleaching.
Subject(s)
Humans , Male , Female , Adolescent , Adult , Young Adult , Oxygen/metabolism , Tooth Bleaching/adverse effects , Dental Pulp/metabolism , Tooth Bleaching Agents/adverse effects , Incisor/metabolism , Reference Values , Time Factors , Tooth Bleaching/methods , Toothpastes/therapeutic use , Oximetry/methods , Treatment Outcome , Dental Pulp/drug effects , Dentin Sensitivity/chemically induced , Dentin Sensitivity/prevention & control , Dentin Desensitizing Agents/therapeutic use , Carbamide Peroxide/adverse effects , Hydrogen Peroxide/adverse effects , Incisor/drug effectsABSTRACT
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.
Subject(s)
Composite Resins/chemistry , Light-Curing of Dental Adhesives/methods , Glass/chemistry , Hot Temperature , Reference Values , Surface Properties , Tensile Strength , Time Factors , Materials Testing , Microscopy, Electron, Scanning , Analysis of Variance , Statistics, Nonparametric , Polymerization/radiation effects , Hardness Tests , Methacrylates/chemistry , MicrowavesABSTRACT
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
Subject(s)
Humans , Female , Adolescent , Composite Resins , Dental Restoration, Permanent , Diastema , Esthetics, Dental , Smiling , Tooth FracturesABSTRACT
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