Evolución histórica de las lámparas de fotopolimerización / Historical evolution of light-cure lamps (photo polymerizations lamps)

Con el advenimiento de las resinas compuestas fotopolimerizables de partículas medianas a principio de los 70 aparecieron al unísono las lámparas de fotocurado o fotopolimerización.1 Desde entonces no se conciben restauraciones con composite donde no estén presentes estos equipos, considerados una de los mayores adelantos para la estomatología contemporánea.1,2Inicialmente se trataba solamente de lámparas que emitían una luz de rayos ultravioleta no visibles, pero que rápidamente fueron desplazadas por los sistemas de luz azul visible que hoy conocemos.1, 3, 4 En la actualidad, las lámparas de fotocurado han evolucionado variando su espectro de luz, su forma ergonómica y su potencia de polimerización, en busca de una mejoría en la calidad de fotocurado de las resinas, las cuales indiscutiblemente constituyen hoy en día uno de los materiales más importantes en Estomatología, pues ofrecen adhesión y estética a la vez...

Bond strength of self-etch adhesives after saliva contamination at different application steps.

This study evaluated and compared the effect of saliva contamination and possible decontamination methods on bond strengths of two self-etching adhesive systems (Clearfil SE Bond [CSE], Optibond Solo Plus SE [OSE]). Flat occlusal dentin surfaces were created on 180 extracted human molar teeth. The two bonding systems and corresponding composite resins (Clearfil AP-X, Kerr Point 4) were bonded to the dentin under six surface conditions (n=15/group): group 1 (control): primer/bonding/composite; group 2: saliva/drying/primer/bonding/composite; group 3: primer/saliva/rinsing/drying/primer/bonding/composite; group 4: primer/saliva/rinsing/drying/bonding/composite; group 5: primer/bonding (cured)/saliva/rinsing/drying/primer/bonding/composite; group 6: primer/bonding (cured)/saliva/removing contaminated layer with a bur/rinsing/drying/primer/bonding/composite. Shear bond strength was tested after specimens were stored in distilled water at 37°C for 24 hours. One-way analysis of variance and Tukey post hoc tests were used for statistical analyses. For CSE, groups 2, 3, and 4 and for OSE, groups 6, 2, and 4 showed significantly lower bond strengths than the control group (p<0.05). CSE groups 5 and 6 and OSE groups 3 and 5 revealed bond strengths similar to the control. When saliva contamination occurred after light polymerization of the bonding agent, repeating the bonding procedure recovered the bonding capacity of both self-etch adhesives. However, saliva contamination before or after primer application negatively affected their bond strength.

The effect of clinical experience on dentine bonding effectiveness: students versus trained dentists.

Clinical successful application of dentine adhesives depends not only on material-related but also on operator-related factors. The purpose of this study was to evaluate the dentine bonding effectiveness of a self-etch composite cement applied by operators with or without clinical experience under well-standardized, randomized and blind conditions. Forty-eight bovine dentine surfaces were randomly divided into two groups. The first group consisted of eight dental students with no clinical experience at all, and the second group consisted of eight dentists with extensive experience in adhesive dentistry (mean experience of 11.4 years). Next, a 4-mm-diameter stainless steel rod (SUS-304) was bonded to the dentine surface using Panavia Fluoro cement (Kuraray Medical Inc., Tokyo, Japan). After application procedures, the specimens were randomized and shear bond-strength measurements were performed by a single blinded operator. Mann-Whitney U test was used to determine statistical differences in bond strength between the two groups, and Kruskal-Wallis was used to determine statistical difference between the student and dentist groups. The means and standard deviations of bond strength were 11.5 +/- 8.1 MPa for the student group and 7.1 +/- 4.3 MPa for the dentist group, respectively. The bond strength of the student group was significantly higher than that of the dentist group. However, the variability in bond strength was significantly higher in the student group, and some specimens failed prior to actual testing (included as 0 MPa). Clinical experience did not have a positive effect on the bonding effectiveness of the self-etch composite cement to dentine.