Changing the bonding force of impression tray to edentulous maxillary jaw simulator with impression valve system: In vitro study

Objective: The aim of this study was to evaluate the effect of an impression valve system (IVS) on the bonding force between an  impression tray and an edentulous maxillary jaw.Materials and Methods: In this in vitro study, a polyether.coated maxillary jaw simulator (PM) was used to model an edentulous maxillary jaw. The IVS was placed into individual impression trays. An irreversible hydrocolloid impression was taken of the PM when the IVS was open and closed. The impression tray bonding force was measured using a digital dynamometer. Student's t.test was used to determine the significance of the difference between these two groups.Results: The impression tray was more easily separated from the PM when the IVS was open (108 ± 3.9 N). The separation was more difficult when the IVS was closed (153.7 ±14.2 N). The difference between these two findings (P = 0.000) was significant.Conclusion: The use of an IVS facilitates the removal of the impression tray from the mouth when taking impressions from an edentulous maxillary jaw.Key words: Bonding force, impression tray, maxillary ja

Surface Roughness of Ceramic-Resin Composites After Femtosecond Laser Irradiation, Sandblasting or Acid Etching and Their Bond Strength With and Without Silanization to a Resin Cement

WOS: 000461566700006PubMed: 29953343Objectives: The aim of this study was to investigate the effects of femtosecond laser irradiation, sandblasting, or acid etching treatments on the surface roughness of ceramic-resin composites and also shear bond strength (SBS) with and without silanization to a resin cement. Methods: Samples of Vita Enamic (VE; Vita Zahnfabrik, Bad Sackingen, Germany) and Lava Ultimate (LU; 3M ESPE, Seefeld, Germany) were classified into control (no treatment), sandblasting, hydrofluoric acid, and femtosecond laser groups (n= 30). Surface roughness was determined using two-dimensional contact profilometry. Surface topography was evaluated using a three-dimensional contact profilometer and a scanning electron microscope. Then groups were divided into two subgroups with similar surface roughness values, including control (C), control + silane (C-S), sandblasting (SB), sandblasting + silane (SB-S), hydrofluoric acid (HF), hydrofluoric acid + silane (HF-S), femtosecond laser (FS), and femtosecond laser + silane (FS-S) groups (n= 15). Panavia F 2.0 resin cement was applied to the sample surfaces using an SDI SBS rig (SDI Limited, Bayswater, Australia). The SBS test was performed after water storage (24 h, 37 degrees C) and thermocycles (2000 cycles, 5 degrees C to 55 degrees C), and failure modes were evaluated. Results: The highest surface roughness was observed in the FS group, and the highest SBS was observed in the FS-S group for both VE and LU (p<0.001). Silanization improved the SBS of VE significantly (p<0.001) in all surface treatments but did not improve that of LU except in the FS group (p=0.004). There was a significantly moderate negative correlation in the VE/SB group (p=0.012) and a moderate positive correlation in the VE/HF group (p=0.049). Conclusions: Femtosecond laser irradiation was found to be more effective than sandblasting or acid etching in increasing the surface roughness, and it was also the most effective surface treatment with silanization on the SBS of a resin cement to the ceramic-resin composites.Office of Scientific Research Projects Coordination of Kirikkale UniversityKirikkale University [2014-20]The authors are grateful to Mr Joshua Cheetham (chief technology officer of SDI Limited) for SDI SBS Rig and to Mr Mekki Kutlu (director of Armaera Digital) for the holder apparatus. This work was supported by the Office of Scientific Research Projects Coordination of Kirikkale University (grant number 2014-20)

Changing the bonding force of impression tray to edentulous maxillary jaw simulator with impression valve system: In vitro study

DEMIRTAG, ZULFIKAR/0000-0002-7122-8876WOS: 000347059000021PubMed: 25511355Objective: The aim of this study was to evaluate the effect of an impression valve system (IVS) on the bonding force between an impression tray and an edentulous maxillary jaw. Materials and Methods: In this in vitro study, a polyether-coated maxillary jaw simulator (PM) was used to model an edentulous maxillary jaw. The IVS was placed into individual impression trays. An irreversible hydrocolloid impression was taken of the PM when the IVS was open and closed. The impression tray bonding force was measured using a digital dynamometer. Student's t-test was used to determine the significance of the difference between these two groups. Results: The impression tray was more easily separated from the PM when the IVS was open (108 +/- 3.9 N). The separation was more difficult when the IVS was closed (153.7 +/- 14.2 N). The difference between these two findings (P = 0.000) was significant. Conclusion: The use of an IVS facilitates the removal of the impression tray from the mouth when taking impressions from an edentulous maxillary jaw

Esthetic impact of gingival plastic surgery from the dentistry students' perspective

Objective: The aim of the this study was to evaluate the perception of smile esthetics and alterations in cases of gingival plastic surgery for correction of a gummy smile, by means of alterations in smile photograph among dentistry degree students. Materials and Methods: A frontal smile photograph of a 40-year-old woman having normal occlusion was used with diverse compositions of gingival exposure level and crown length of maxillary teeth. The eight photographs were evaluated by 216 dentistry students in five class groups (1st, 2nd, 3rd, 4th and 5th classes). Results: The results revealed that almost all of the class' students perceived differences between images, additionally, the highest percentage of students that answered "no difference" was 12% at 1st class' students. 1st and 2nd class' students most liked photograph which is 2.5 mm gingival display and 3rd class students liked two different photographs which are 2.5 mm gingival display and 2 mm gingival display whereas 4th class students preferred two different photographs which are 1.5 mm gingival display and 1 mm gingival display, 5th class students preferred photograph which is 1.5 mm gingival display as the most. Conclusion: Esthetic perception of smile improve as a student passes to higher study classes in terms of gingival exposure. The harmonious display of gingiva exhibits an important effect in the smile esthetics rather than reduced or excessive display. © 2016 European Journal of Dentistry | Published by Wolters Kluwer-Medknow

Effect of femtosecond laser beam angle on bond strength of zirconia-resin cement

KEPCEOGLU, Abdullah/0000-0002-4743-5517; DEMIRTAG, ZULFIKAR/0000-0002-7122-8876;WOS: 000362583600010PubMed: 25958172Yttrium-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic is widely used as an all-ceramic core material because of its enhanced mechanical and aesthetic properties. The bond strength of Y-TZP restorations affects long-term success; hence, surface treatment is required on ceramic boundaries. This study evaluated the effect of different laser beam angles on Y-TZP-resin cement shear bond strength (SBS). Forty plates of Y-TZP ceramics were randomly assigned to four groups (n = 10). A femtosecond amplifier laser pulse was applied on Y-TZP surface with different incidence angles (90A degrees, 75A degrees, 60A degrees, 45A degrees). The resin cement was adhered onto the zirconia surfaces. The SBS of each sample was measured using universal testing machine at crosshead speed of 1 mm/min. The SBS was analyzed through one-way analysis of variance (ANOVA)/Tukey tests. The results showed that the degree of laser beam angle affects the SBS of resin cement to Y-TZP. The laser beam was applied to a surface with a 45A degrees angle which resulted in significantly higher SBS (18.2 A +/- 1.43 MPa) than other groups (at 90A degrees angulation (10.79 A +/- 1.8 MPa), at 75A degrees (13.48 A +/- 1.2 MPa) and at 60A degrees (15.85 A +/- 0.81 MPa); p < 0.001). This study shows that decreasing of the angle between the ceramic surface and the laser beam increased the SBS between the resin cement and the ceramic material, as well as the orifice