ABSTRACT
PURPOSE@#This study investigated the physical and mechanical changes in the titanium base of three different hybrid abutment materials after cyclic loading by estimating the post-load reverse torque value (RTV), compressive side fulcrum wear pattern of titanium base, and surface roughness. @*MATERIALS AND METHODS@#A total of 24 dental implants were divided into three groups (n = 8 each): Group Z, LD, and P used zirconia, lithium disilicate, and polyetheretherketone, respectively, for hybrid abutment fabrication. RTV was evaluated after cyclic loading with 50 N for 1.2 × 106 chewing cycles. The compressive sides of the titanium bases were analyzed using a scanning electron microscope, and the roughness of the affected areas was measured using an optical profilometer after loading. Datasets were analyzed using Kruskal–Wallis test followed by Mann-Whitney tests with the Bonferroni correction (α = .05). @*RESULTS@#Twenty-three samples passed the test; one LD sample fractured after 770,474 cycles. Post-load RTV varied significantly depending on the hybrid-abutment material (P = .020). Group P had a significantly higher median of post-load RTVs than group Z (16.5 and 14.3 Ncm, respectively). Groups LD and P showed minor signs of wear, and group Z showed a more pronounced wear pattern. While evaluating compressive side affected area roughness of titanium bases, lower medians were shown in group LD (Ra 0.16 and Rq 0.22 µm) and group P (Ra 0.16 and Rq 0.23 µm) than in group Z (Ra 0.26 and Rq 0.34 µm); significant differences were found only among the unaffected surface and group Z. @*CONCLUSION@#The hybrid abutment material influences the post-load RTV. Group Z had a more pronounced wear pattern on the compressive side of titanium base; however, the surface roughness was not statistically different among the hybrid-abutment groups.
ABSTRACT
PURPOSE@#. This study evaluated screw loosening and 3D crown displacement after cyclic loading of implant-supported incisor crowns cemented with original titanium bases or with three compatible, nonoriginal components. @*MATERIALS AND METHODS@#. A total of 32 dental implants were divided into four groups (n = 8 each): Group 1 used original titanium bases, while Groups 2-4 used compatible components. The reverse torque value (RTV) was evaluated prior to and after cyclic loading (1,200,000 cycles). Samples (prior to and after cyclic loading) were scanned with a microcomputed tomography (micro-CT). Preload and postload files were superimposed by 3D inspection software, and 3D crown displacement analysis was performed using root-mean-square (RMS) values. All datasets were analyzed using one-way ANOVA and Tukey’s post hoc analysis. RESULTS. Significant variations were observed in the postload RTV, depending on the titanium base brand (P < .001). The mean postload RTVs were significantly higher in Groups 1 and 2 than in the other study groups. While evaluating 3D crown displacement, the lowest mean RMS value was shown in the original Group 1, with the highest RMS value occurring in Group 4. @*CONCLUSION@#. Within the limitations of this in vitro study and under the implemented conditions, it was concluded that the manufacturer brand of the titanium base significantly influenced screw loosening following the fatigue test and influenced 3D crown displacement after cyclic loading.
ABSTRACT
Sialolithiasis is a multi-factorial pathology that accounts for more than 50% of salivary gland disease. However,the exact impact of salivary pH and calcium (Ca2+) and phosphate (PO43−) on the sialoliths' formation stillremains unknown. Materials and Methods: Seven removed sialoliths were put into flasks with artificial salivasolution that differed in concentrations of Ca2+ and PO43−. The changes in weights of sialoliths and alterations inpH had been measured for 13 weeks. Concentrations of Ca2+ and PO43− in the artificial saliva solution wereestimated at the beginning and at the end of the experiment. Results: Sialoliths' weight decrease was observedfrom the 2nd to 7th week. It occurred parallel with natural pH decrease (from 7 to 6.5 pH). Sialoliths’ weightsstarted increasing after pH was adjusted with NaOH. Analyzing the concentration changes of Ca2+ in everyflask, it was determined that from natural or double Ca2+ concentration, it decreased till similar amount (7–14times). Analyzing the concentration changes of PO43−, it was determined that from natural or doublePO43− concentration it decreased 24 times. Conclusions: Sialoliths' weights decreased parallel with natural pHdecrease and sialoliths grew when pH was adjusted. PO43− ions concentration decreased relatively more thanCa2+ ions concentration.