A Zarbakhsh, A Mazaheri Tehrani, F Shamshirgar, H Khosroshahi,
Volume 3, Issue 3 (8-2018)
Abstract
Background and Aim: The mismatch of the implant-abutment connection can produce instant stress and microleakage which result in mechanical and biological complications. This study aimed to investigate the influence of GapSeal® as a sealing material on the extent of microgap and microleakage at the external hexagon implant platform following cyclic loading.
Materials and Methods: Sixteen implants with an external-hexagon connection (BioHorizons External dental implant) were employed in this in-vitro experimental study. All implant-abutment sets were assigned to two groups and were molded in acrylic resins. GapSeal® was injected into the implants in the experimental (test) group. Then, implant assemblies were tightened with the torque of 30 N/cm, and 1200,000 loading cycles with the force of 100 N and the frequency of 1 Hz were applied. Every sample was immersed in a methylene blue dye to evaluate microleakage. Microgap was measured in six regions randomly using a scanning electron microscope (SEM). The data were entered into SPSS 22 and were analyzed using t-test.
Results: The mean±SD microgap was 0.87±0.35 µm and 3.43±1.61 µm in the test and control groups, respectively. Methylene blue dye was observed in all of the specimens of the control group, while no liquid was seen in the test group. A significant statistical difference was found between the groups regarding the microgap and microleakage (P<0.0001).
Conclusion: Application of GapSeal® reduced the dimension of the microgap and decreased microleakage at the implant-abutment interface.
Shaghayegh Shahidi, Solmaz Heidari, Maryam Rahimikhoob, Bahareh Farar, Shadab Safarzadeh Khosroshahi,
Volume 9, Issue 3 (9-2024)
Abstract
Background and Aim: Postoperative tooth hypersensitivity after restorative procedures is a common finding. Considering the obstruction of dentinal tubules following the use of dentin desensitizers, there are some concerns about the effects of desensitizers on the bond strength of bonding systems. This study aimed to assess the effect of a desensitizer on microshear bond strength (µSBS) of two bonding systems.
Materials and Methods: In this in vitro study, 20 sound human molars were mesiodistally sectioned into halves, and the roots were cut at the cementoenamel junction. The samples (n=40) were then randomly divided into four groups (n=10): (I) Adper™ Single Bond 2, (II) Desensibilize desensitizing agent+ Adper™ Single Bond 2, (III) Single Bond Universal, and (IV) Desensibilize desensitizing agent + Single Bond Universal. Adhesives and desensitizing agents were applied according to the manufacturers’ instructions. Filtek Z250 composite cylinders were fabricated and bonded to dentin surfaces. The µSBS of each sample was then measured. Data were analyzed by one-way ANOVA and a post-hoc test (P<0.05).
Results: A reduction in µSBS was found following the application of desensitizing agent in combination with AdperTM Single Bond 2 (P<0.05). The µSBS increased when the desensitizing agent was applied in combination with Single Bond Universal. However, this difference was not significant (P˃0.05).
Conclusion: Desensibilize desensitizing agent affected the dentinal tubule obstruction and decreased the µSBS when used with AdperTM Single Bond 2 total-etch system, while the µSBS increased when it was used with Single Bond Universal adhesive.
