Evaluation of effect on stability of implants with and without platelet rich fibrin using a resonance frequency analyzer - An in-vivo study

Background

Although the conventional replacement for lost teeth has been partial or full dentures, the need for a fixed, esthetic, and functional restoration makes dental implants a reliable alternative.

Aim

To evaluate the initial and final stability of platelet rich fibrin coated implants using resonance frequency analyzer.

Method

ology: Thirteen patients with two or more missing teeth were informed about the procedure, and a consent form was obtained after cone beam computer tomography evaluation. Blood was drawn from the anticubital area of the patient, which was centrifuged to obtain platelet-rich fibrin. In all, 26 implants were placed, among which 13 were platelet-rich fibrin-coated (test group) and 13 were without platelet-rich fibrin (control group), and implant stability quotient values were recorded.

Results

The mean age of the patients was 34.4 (SD = 4.28). Majority of the patients were males (9; 69.2%) whereas there were only four (30.8%) female patients. When comparison between overall primary implant stability with and without PRF was done, the mean difference was 5.12 and this difference was not statistically significant (p = 0.221) whereas a statistically significant difference (p = 0.019) was found when comparison between overall secondary implant stability was done with and without PRF. The primary and secondary stability values for the control group were 69.18 ± 7.45 and 73.84 ± 8.21 respectively, and the primary and secondary stability values for the test group were 64.06 ± 12.66 and 81.49 ± 7.61 respectively, which showed statistically significant differences among the groups. The difference in these values signify that primary stability is more in control group whereas secondary stability is more in case group. This signifies that PRF enhances the stability of implant.

Conclusion

Implants coated with platelet-rich fibrin exhibited better osseointegration than implants without platelet-rich fibrin.

Comparative Evaluation of Metal-ceramic Bond Strengths of Nickel Chromium and Cobalt Chromium Alloys on Repeated Castings: An In vitro Study

BACKGROUND

Recasting the base metal alloys is done as a routine procedure in the dental laboratories whenever there is casting failure or to decrease the unit cost of a fixed partial denture. However, this procedure may affect the metal ceramic bond. Furthermore, it is unclear, as to which test closely predicts the bond strength of metal-ceramic interface. The aim was to compare the bond strength of nickel chromium (Ni-Cr) and cobalt chromium (Co-Cr) alloys with dental ceramic on repeated castings using shear bond test with a custom made apparatus.

MATERIALS AND METHODS

Sixty metal ceramic samples were prepared using Wiron 99 and Wirobond C, respectively. Three subgroups were prepared for each of the groups. The first subgroup was prepared by casting 100% fresh alloy. The second and third subgroups were prepared by adding 50% of fresh alloy and the remnants of the previous cast alloy. The bond load (N) between alloy and dental porcelain was evaluated using universal testing machine using a crosshead speed of 1 mm/min, which had a 2500-kgf load cell. Mean values were compared using oneway analysis of variance with post-hoc Tukey's test and Student's t-test.

RESULTS

The mean shear bond load of A0 (842.10N) was significantly higher than the load of A1 (645.50N) and A2 (506.28N). The mean shear bond load of B0 (645.57N) was significantly higher than the load of B1 (457.35N) and B2 (389.30N).

CONCLUSIONS

Significant reduction in the bond strength was observed with the addition of the first recast alloy (A1 and B1) compared with the addition of second recast alloy (A2 and B2). Ni-Cr alloys (664.63N) showed higher bond strengths compared to that of Co-Cr alloys (497.41N). The addition of previously used base metal dental alloy for fabricating metal ceramic restorations is not recommended.