This study evaluated the fracture resistance of teeth submitted to internal bleaching and restored with different procedures. Forty maxillary incisors were endodontically treated and assigned to 4 groups (n=10): G1- restored with composite resin (CR), G2- bleached with hydrogen peroxide (HP) and restored with CR, G3- restored with CR and fiberglass posts (CR + posts) and G4- bleached and restor...

The production of singleand mixed-sugar streams and their conversion to bioproducts were studied using sulfite pulping streams as feedstocks. Sulfite pulp, sludge, and spent sulfite liquor (SSL) were utilized because they are concurrently generated alongside of bleached pulp, and because the pulping process renders pretreatment unnecessary. SSL, comprised of mostly monomeric hexose and pentose ...

the aim of this work was to study the ability of two biodegradable chelating agents, nitrilotriaceticacid (nta) and ethylenediiminopropanedioic acid (eddm) to complex metals, in the treatment of the pulp,prior to a totally chlorine free (tcf) bleaching process, and compare with the ethylenediaminetetraacetic acid(edta) performance. firstly, speciation efficiency index (sei) was calculated by co...

Effectiveness of ozonation before and after biological treatment for removal of recalcitrant organic matter in bleached kraft pulp effluents was compared. Two industrial ECF bleached eucalypt kraft pulp effluents (E1 and E2) were pretreated with 100 mg O3/L. Raw and pretreated effluents were treated biologically in bench-scale sequencing batch reactors, under constant conditions. Following biol...

Pectins are important structural elements in spruce fibres. Alkaline peroxide bleaching of spruce thermomechanical pulp (TMP) causes degradation and demethylation of pectins, yielding high-charge-density pectic acids. The pectic acids in fibres contribute strongly to the negative fibre charge, and the dissolved pectic acids increase the cationic demand of bleached TMP water. In this study, a me...

This study evaluated the microtensile bond strength (μTBS) of 1-step self-etch adhesives (1-SEAs) and 2-step self-etch adhesives (2-SEAs) to pulp chamber dentin immediately after bleaching with 2 types of common bleaching techniques. Pulp chamber dentin of bovine teeth was bleached using 30% hydrogen peroxide (H2O2) solution with quartz-tungsten-halogen light-curing unit (Group 1) and 3.5% H2O2...

The paper industry has taken various steps to address environmental concerns and raw material limitations. Among them, paper recycling has been shown to be a viable option. In this study, the alkaline sulfite pulping of old corrugated containers (OCC) to produce bleachable pulp was investigated. A combination of one of the three active alkali levels (14, 16, and 18%; Na2O, and oven-dry weight o...

This study demonstrates the feasibility of integrating the production of nano-fibrillated cellulose (NFC), a potentially highly valuable biomaterial, with sugar/biofuel (ethanol) from wood fibers. Commercial cellulase enzymes were used to fractionate the less recalcitrant amorphous cellulose from a bleached Kraft eucalyptus pulp, resulting in a highly crystalline and recalcitrant cellulose (RC)...

Global sustainability megatrends are promoting the utilization of sustainably perceived fibers such as recycled and agricultural residue in hygiene tissue applications. Tissue paper products advertised sustainable have higher prices inferior performance than conventional manufactured from virgin wood fibers. This work demonstrates feasibility using residues fique plantations (Furcraea microphyl...

oxygen delignified kraft pulp from eucalyptus (e. urophylla × e. grandis) was catalytically pretreated in aerobic condition using ammonium persulfate in present of catalists like cupric acetate and/or cobalt acetate in acetic acid-water solution, i. e. s2o82--cu2+, s2o82--co2+ and s2o82--(cu2++co2+). final bleached pulp after pretreatment with the three catalytic systems showed higher delignifi...