ABSTRACT
This study evaluated in vitro the influence of thermocycling and water storage (WS) on the shear bond strength (SBS) of composite resin in cavities prepared in primary tooth enamel with conventional bur or Er:YAG laser. The test surfaces were obtained from 48 primary molars and randomly assigned to 2 groups (n=24), according to cavity preparation: A: bur-preparation and B: Er:YAG laser irradiation. The specimens were restored with an etch-and-rinse adhesive system and composite resin. Each group was divided into 4 subgroups (n=6) according to WS duration and number of thermal cycles (TCs): I: 24 h WS/no thermocycling; II: 7 days WS/500 TCs; III: 1 month WS/2,000 TCs; IV: 6 months WS/12,000 TCs. The specimens were tested to failure in shear strength at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by two-way ANOVA and Tukey's test. SBS means (S.D.) in MPa were: AI: 17.45 (2.03), AII:16.38 (1.49), AIII: 6.88 (0.66), AIV: 7.77 (1.53), BI: 12.32 (0.99), BII: 15.37 (2.24), BIII: 15.05 (2.01) and BIV-5.51 (1.01). WS duration and number of TCs influenced significantly the SBS values only for BIV (p<0.05). AI presented the highest SBS value, which was statistically similar to those of AII, BII and BIII. In conclusion, the adhesion of an etch-and-rinse adhesive to Er:YAG laser-irradiated primary tooth enamel was affected by the methods used to simulate degradation of the adhesive interface only when 6 months WS/12,000 TCs were employed.
Este estudo avaliou in vitro a influência da termociclagem (TC) e do armazenamento em água (AA) na resistência ao cisalhamento de resina composta ao esmalte de dentes decíduos preparados com broca convencional e laser Er:YAG. As superfícies de trabalho foram obtidas de 48 molares decíduos e divididas aleatoriamente em dois grupos (n=24), de acordo com o tipo de preparo cavitário: A - preparo com broca; B - irradiação com laser Er:YAG. Os espécimes foram restaurados com um sistema adesivo etch-and-rinse e resina composta. Cada grupo foi dividido em 4 subgrupos (n=6) de acordo com o tempo de armazenamento em água (AA) e o número de termociclagens (TCs): I - 24 h AA/0 TCs, II - 7 dias AA/500 TCs; III - 1 mês AA/2000 TCs; IV - 6 meses AA/12000 TCs. O teste de cisalhamento foi realizado em máquina de ensaio universal a uma velocidade de 0,5 mm/min. Os dados foram analisados estatisticamente pelo teste ANOVA a dois critérios e teste de Tukey. As médias de resistência ao cisalhamento (D.P.), em MPa, foram: AI: 17,45 (2,03), AII: 16,38 (1,49), AIII: 6,88 (0,66), AIV: 7,77 (1,53), BI: 12,32 (0,99), BII: 15,37 (2,24), BIII: 15,05 (2,01) e BIV-5,51 (1,01). O tempo de armazenamento em água quanto a termociclagem influenciou significativamente os valores de resistência ao cisalhamento só para o grupo BIV (p<0,05). AI apresentou o maior valor de SBS, que foi estatisticamente semelhantes aos de AII, BII e BIII. Em conclusão, a adesão de um sistema adesivo etch-and-rinse ao esmalte de dente decíduo irradiado com Er: YAG foi afetada pelos métodos empregados para simulação da degradação da interface adesiva somente quando armazenamento em água por 6 meses e 12.000 ciclos de termociclagem foram empregados.
Subject(s)
Humans , Dental Enamel/radiation effects , Lasers, Solid-State , Tooth, Deciduous/radiation effects , Resins, Synthetic , Shear StrengthABSTRACT
Crown dilaceration of permanent teeth occurs due to the non-axial displacement of the already formed hard tissue portion of the developing crown at an angle to their longitudinal axis due to trauma to the primary predecessors. This is a rare condition, representing only 3% of the total of injuries to developing teeth and usually occurs in permanent maxillary incisors because of the close proximity of their tooth germs to the primary incisors, which are more susceptible to trauma. This alteration frequently results from the intrusion of a primary tooth when the child is around 2 years of age, at which time half of the crown of the permanent successor is already formed. Teeth with dilacerated crowns may either erupt with buccal or lingual displacement or remain impacted. The treatment may involve endodontic, orthodontic, restorative and prosthetic procedures. This paper reports the restorative treatment proposed to reestablish the esthetics and function of the affected teeth in three cases of crown dilaceration in permanent maxillary incisors after trauma to their primary predecessors.
Subject(s)
Child , Female , Humans , Male , Tooth Avulsion/complications , Tooth Crown/injuries , Tooth, Deciduous/injuries , Tooth, Impacted/etiology , Tooth, Unerupted/pathology , Dentition, Permanent , Tooth Injuries/diagnosis , Tooth Injuries/therapy , Tooth, Impacted/therapyABSTRACT
This study evaluated in vitro the shear bond strength of a resin-based pit-and-fissure sealant (Fluroshield - F) associated with either an ethanol-based (Adper Single Bond 2 - SB) or an acetone-based (Prime & Bond - PB) adhesive system under conditions of oil contamination. Mesial and distal enamel surfaces from 30 sound third molars were randomly assigned to 2 groups (n=30): I - no oil contamination; II - oil contamination. Contamination (0.25 mL during 10 s) was performed after 37 percent phosphoric acid etching with an air/oil spray. The specimens were randomly assigned to subgroups, according to the bonding protocol adopted: subgroup A - F was applied to enamel without an intermediate bonding agent layer; In subgroups B and C, SB and PB, respectively, were applied, light-cured, and then F was applied and light-cured. Shear bond strength was tested at a crosshead speed of 0.5 mm/min in a universal testing machine. Means (± SD) in MPa were: IA-11.28 (±1.84); IIA-12.02 (±1.15); IB-9.73 (±2.38); IIB-9.62 (±2.29); IC-28.30 (±1.63); and IIC-25.50 (±1.91). It may be concluded that the oil contamination affected negatively the sealant bonding to enamel and the acetone-based adhesive system (PB) layer applied underneath the sealant was able to prevent its deleterious effects to adhesion.
Este estudo avaliou in vitro a resistência ao cisalhamento (RC) de um selante resinoso [Fluroshield (F); Dentsply/Caulk] em associação com um sistema adesivo com solvente a base de etanol [Adper Single Bond 2 (SB); 3M/ESPE] ou a base de acetona [Prime & Bond (PB); 3M/ESPE] após contaminação com óleo do esmalte. Superfícies mesiais e distais de esmalte de 30 terceiros molares hígidos foram aleatoriamente alocadas em 2 grupos (n=30): I - contaminação com óleo; II - sem contaminação. A contaminação foi realizada (0,25 mL;10 s) com um jato de ar/óleo após o condicionamento do esmalte com ácido fosfórico a 37 por cento. Os espécimes foram aleatoriamente alocados em subgrupos, de acordo com a técnica adesiva empregada: A - F foi aplicado sobre o esmalte condicionado sem sistema adesivo; B - SB + F; C - PB + F. RC foi testada em uma máquina universal de ensaios (0,5 mm/min; 50 kgf) e os dados analisados por ANOVA e t-teste (α=0,01). As médias de RC em MPa foram: IA-11,28 (±1,84); IIA-12,02(±1,15); IB-9,73 (±2,38); IIB-9,62 (±2,29); IC-28,30 (±1.63); e IIC-25,50 (±1,91). Conclui-se que a contaminação com o óleo afetou a adesão do selante resinoso ao esmalte e o sistema adesivo com solvente a base de acetona (Prime & Bond) aplicado sob o selante foi capaz de impedir os efeitos deletérios da contaminação com óleo.
Subject(s)
Humans , Dentin-Bonding Agents/chemistry , Light-Curing of Dental Adhesives , Pit and Fissure Sealants/chemistry , Acid Etching, Dental , Acetone/chemistry , Bisphenol A-Glycidyl Methacrylate/chemistry , Drug Contamination , Dental Enamel/ultrastructure , Dental Stress Analysis/instrumentation , Ethanol/chemistry , Materials Testing , Oils/chemistry , Phosphorous Acids , Phosphoric Acids/chemistry , Polymethacrylic Acids/chemistry , Polyurethanes/chemistry , Shear Strength , Stress, Mechanical , Solvents/chemistry , Temperature , Time Factors , Water/chemistryABSTRACT
Objetivos: realizar uma breve revisão da literatura a respeito da sintomatologia associada a erupção dental a fim de chamar a atenção dos profissionais da saúde que prestam atendimento a crianças para o desenvolvimento de trabalhos de pesquisa nesta área...
Objectives: to carry out a brief review of the literature about the symptomatoly associated to dental eruption in order to call the attention of helath professionals assisting children to the development of research works in this field...