1.
Effect of solvent type on microtensile bond strength of a total-etch one-bottle adhesive system to moist or dry dentin.
Cardoso, Pde C, Lopes, GC, Vieira, LC, Baratieri, LN
Operative dentistry. 2005;(3):376-81
Abstract
This study evaluated the effect of organic solvent (acetone or ethanol) on the microtensile bond strengths (MTBS) of an adhesive system applied to dry and moist dentin. Sixteen extracted human third molars were ground to expose a flat occlusal dentin surface and acid etched for 20 seconds (20% phosphoric acid gel, Gluma Etch 20 Gel, Heraeus/Kulzer). After rinsing the acid etchant, an ethanol-based one-bottle adhesive system was applied to the mesial half of the occlusal dentin surface. An acetone-based, one-bottle adhesive system was applied to the distal half of the ground dentin surface. The teeth were randomly assigned to groups. In Group 1, the etched dentin was thoroughly air dried and an ethanol-based one-bottle adhesive system was applied (Gluma Comfort Bond, Heraeus/Kulzer) (GCB). In Group 2, the etched dentin was thoroughly air dried and an acetone-based one-bottle adhesive system was applied (Gluma One Bond, Heraeus/Kulzer)(GOB). In Group 3, excess moisture was removed after acid etching, leaving a moist dentin surface and a one-bottle ethanol-based adhesive was applied (Gluma Comfort Bond). In Group 4, excess moisture was removed after acid etching, leaving a moist dentin surface and an acetone-based adhesive was applied (Gluma One Bond). A hybrid resin composite (Venus, Heraeus/Kulzer) was applied to the bonded surface in four 1-mm increments and light cured according to manufacturer's directions. The specimens were then sectioned with a slow-speed diamond saw in two perpendicular directions to obtain sticks with a cross-section of 0.5 +/- 0.05 mm2. The microtensile bond strength (MTBS) test was performed with a Bencor device in an Instron machine at a crosshead speed of 0.5 mm/minute. The data were subjected to a two-way ANOVA and Scheffé Post hoc test (p < 0.05). The experimental MTBS measured for dry dentin were Group 1 = 37.0 +/- 10.6 and Group 2 = 34.7 +/- 9.0 in MPa (mean +/- SD); and on moist dentin, Group 3 = 50.7 +/- 11.0 and Group 4 = 38.5 +/- 10.5 in MPa (mean +/- SD). The ethanol based adhesives resulted in higher MTBS than acetone-based adhesive (p < 0.008) and bonding to moist dentin resulted in higher MTBS (p < 0.001). GCB applied on moist dentin resulted in statistically higher bond strengths than the other groups. The highest MTBS were achieved with the use of an ethanol-based adhesive to moist dentin.
2.
Effect of solvents on bonding to root canal dentin.
Erdemir, A, Eldeniz, AU, Belli, S, Pashley, DH
Journal of endodontics. 2004;(8):589-92
Abstract
The long-term success of resin cementation of post/cores is likely increased with improvement in resin-root canal dentin bonding. The adverse effect of some irrigation constituents (NaOCl, H2O2) or medications (eugenol) on the bond strengths of resins to dentin have been reported. The purpose of this in vitro study was to evaluate the effect of two gutta-percha solvents (chloroform versus halothane) on microtensile bond strength to root canal dentin. Thirty, extracted, human, single-rooted teeth were instrumented to a #70 file and randomly divided into 3 groups of 10 each. The root canals were treated with water, chloroform, or halothane for 60 s. All root canals were obturated using C&B Metabond. After 24 h of storage in distilled water, serial 1-mm-thick cross-sections were cut and trimmed. Microtensile bond strength to apical, middle, and coronal root canal dentin were measured using an Instron machine. Using pooled data, the results indicated that water-treated roots had significantly higher resin-dentin bond strengths compared with chloroform or halothane treatment groups (control: 23.9 MPa; chloroform: 18.3 MPa; halothane: 17 MPa; p < 0.05). Gutta-percha solvents have an adverse effect on bond strengths of adhesive cements to root canal dentin.
3.
Percutaneous ethanol (PEIT) and calcitrol (PCIT) injection therapy are ineffective in treating severe secondary hyperparathyroidism.
de Barros Gueiros, JE, Chammas, MC, Gerhard, R, da Silva Dias Boilesen, CF, de Oliveira, IR, Moysés, RM, Jorgetti, V
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. 2004;(3):657-63
Abstract
BACKGROUND Secondary hyperparathyroidism (2HPT) is a frequent complication of long-term dialysis treatment and, despite recent advances in medical therapy, surgical parathyroidectomy (PTX) is required in a considerable number of uraemic patients. Recently, other modalities of therapy, such as ultrasound-guided percutaneous parathyroid injection of ethanol (PEIT) or of calcitriol (PCIT), have been used to treat refractory 2HPT. Our objectives were to evaluate the efficacy of these therapeutic modalities and to analyse their effects on parathyroid cell proliferation. METHODS Nineteen haemodialysis patients with severe 2HPT were studied. Ten underwent PEIT (Group I) and nine underwent PCIT (Group II). After treatment, five patients in each group were submitted to PTX. Parathyroid cell proliferation was appraised at the beginning and at the end of the study by fine-needle aspiration biopsy, making use of immunocytochemical testing for Ki-67. The surgically removed glands were submitted to histopathological analysis and cellular proliferation was evaluated. RESULTS Both PEIT and PCIT proved inefficient in controlling 2HPT. Comparing study onset with day 60, both groups showed a significant decrease in serum-ionized calcium: 5.3+/-0.3 vs 5.1+/-0.5 mg/dl (P = 0.03) in Group I and 5.5+/-0.4 vs 5.4+/-0.3 mg/dl (P = 0.03) in Group II. Other laboratory parameters were unchanged. There was a significant, although transitory, enlargement in glandular volume in Group II at day 30 when compared with study onset (1.5+/-0.6 vs 1.7+/-0.7 cm(3), P = 0.02). When comparing the two groups, Group I showed a glandular volume smaller than that of Group II at days 30 (1+/-0.5 vs 1.7+/-0.7 cm(3), P = 0.003), 60 (0.8+/-0.4 vs 1.5+/-0.9 cm(3), P = 0.006) and 90 (0.8+/-0.5 vs 1+/-0.7 cm(3), P = 0.02). Cellular proliferation, which was equally elevated in both groups at the beginning of the study, could not be evaluated at the end due to lack of material. The majority of glands obtained through PTX presented intensive cellular proliferation and contained areas of nodular hyperplasia, even those glands with a volume of <0.5 cm(3). CONCLUSION In our experience, both PCIT and PEIT were unable to control severe 2HPT in chronic haemodialysis patients. We believe that the severity of the 2HPT in the study patients, in conjunction with the fact that we excluded from treatment parathyroid glands with a volume of <0.5 cm(3), were the most important causes of this failure.