Comparative evaluation of effect of metal primer and sandblasting on the shear bond strength between heat cured acrylic denture base resin and cobalt-chromium alloy: An in vitrostudy

Aims: The aim of this study was to evaluate the effect of metal primers and sandblasting on the shear bond strength (SBS) of heat cured acrylic denture base resin to cobalt-chromium (Co-Cr) alloy. Materials and Methods: A total number of 40 disk shaped wax patterns (10 mm in diameter and 2 mm in thickness) were cast in Co-Cr alloy. Samples were divided into 4 groups depending on the surface treatment received. Group 1: No surface treatment was done and acts as control group. Group 2: Only sandblasting was done. Group 3: Only metal primer was applied. Group 4: Both metal primer and sandblasting were done. After surface treatment samples had been tested in Universal Testing Machine at crosshead speed of 0.5 mm/min in shear mode and scanning, electron microscope evaluation was done to observe the mode of failure. Statistical Analysis: All the observations obtained were analyzed statistically using software SPSS version 17; one-way analysis of variance (ANOVA) and post-hoc Tukey test were applied. Results: The one-way ANOVA indicated that SBS values varied according to type of surface treatment done. The SBS was highest (18.70 ± 1.2 MPa) when both sandblasting and metal primer was done when compared with no surface treatment (2.59 ± 0.32 MPa). Conclusions: It could be concluded that the use of metal primers along with sandblasting significantly improves the bonding of heat cured acrylic denture base resin with the Co-Cr alloy

Evaluating bond strength of acrylic teeth to conventional and high impact denture base resin incorporating various groove designs

Purpose: In spite of chemical union between acrylic resin teeth and acrylic denture base material, detachment of teeth particularly anterior teeth is a frequent observation. The purpose of this study was to evaluate shear bond strength between denture base resin and acrylic resin denture teeth after incorporating various grooves on the ridge lap area. Materials & Methods: A total of 60 samples were prepared and divided into two groups with 30 samples each. Sample in group I were processed with conventional resin whereas in group II with high impact resin. The teeth in each group were subjected to no treatment, vertical groove & Horizontal retentive goove placement on the ridge lap area. In each group unmodified teeth served as control. A shear force was applied at an angle of 130 degrees to the lingual surface of teeth using instron universal testing machine until fracture occurred. Data obtained was statistically analysed using Post hoc and Mann-Whitney Test. Results: Unmodified resin teeth showed the least bond strength. Modification of teeth with vertical and horizontal groove significantly improves the bond strength with denture resin. A significantly greater force was required to fracture teeth from high impact resin and with vertical groove

Assessment of allograft and bioresorbable xenograft in immediate implant placement

Background: Use of grafts helps in healing and successful outcome of immediate dental implants. Materials & Methods: The study comprised a total of twenty four individuals in the age groupbetween 20 and 56 years with at least one tooth indicated for extraction. The twenty four subjects were divided into two groups; Group Aallograft with implant and Group B-xenograft with implant. The participantswere evaluated both clinically (plaque, probing depth) and radiographically for 3 months, 6 months, and 1 year. The level ofsignificance was set at P < 0.05. Results: Xenograft in immediate implant site showed excellent osseointegration around the immediate implant site. However, the difference between the groups was not statistically significant. Conclusion: Both synthetic allograft and bioresorbable xenograft are promising and equally potential in bone formation around the immediate implant site