Background and Aims: One of the decisive factors on the final esthetic results of implant treatment is the abutment material. Ceramic abutments are nowadays very popular in this regard. The purpose of this study was to compare the fracture resistance of three Zirconia abutments with titanium abutment.Materials and Methods: Four groups of abutments (five specimens in each) were prepared. The abutments were prefabricated titanium, prefabricated Zirconia, Zirconia-metal, and copy-milled Zirconia abutment. After securing the abutments to the implant using a torque of 24 Ncm, they were mounted into a mounting jig using the 30o tilt.The force was applied on the assembly till the failure occurred. Facture resistance and mode of failure were recorded for each specimen. The data were analyzed using One-way ANOVA.Results: The mean values recorded for fracture resistance of different Zirconia abutments varied between 426 to 688 N, however, there was no significant differences among the groups (P=0.14). Body fracture was observed only in prefabricated Zirconia abutments. Screw fracture and screw bending were the common failures observed in other groups.Conclusion: Zirconia abutments of any type could be successfully used in regular platform implants.

Background and Aims: In response to esthetic demand of patients, ceramic abutments have been developed. In spite esthetic of Zirconia abutments, machining accuracy of these abutments has always been a question. Any misfit in the abutment-implant interface connection can lead to detorque and screw loosening. The aim of this study was to compare torque loss value of manually aided design/manually aided manufacture (MAD/MAM) Zirconia abutments with prefabricated titanium abutments.Materials and Methods: Seven titanium abutments (Branemark RP, Easy abutment) and seven copy milled abutments which were duplicated from the prefabricated one in Zirkonzhan (ZirkonZahn, Sand in Taufers, Italy) were prepared. After sintering process of Zirconia abutment, all abutments were fastened with a torque screw under 35 Ncm. Detorque measurements were performed per group pushing the reverse button of the Torque controller soon after screw tightening with values registered. The mean torque loss were calculated and compared by a Student’s t test.Results: The mean of torque loss was 12.71 Ncm with standard deviation of 1.70 for prefabricated titanium abutments and 15.50 Ncm with standard deviation of 4.67 for MAD-MAM abutments. The difference between the two groups was not statistically significant (P=0.23).Conclusion: Within the limitation of this study MAD-MAM ceramic abutments could maintain the applied torque comparing to the prefabricated abutments.

Purpose: In this study, the fracture resistance of prosthetic screws was tested using abutments made of titanium, Zirconia, and Polyether Ether Ketone (PEEK) on dental implants. Materials and Methods: From Easy Implant by easy prod, France, dental implants with specified dimensions and prosthetic screws were purchased. Three different materials (Ti, Zr, and PEEK) were used for abutment preparation. The implant-abutment units were subjected to a constant vertical force using a Universal Testing Machine (UTM) until the prosthetic abutment broke. The force that caused fracture was measured, and one-way ANOVA and Tukey's post-hoc tests were used to statistically analyze the data. Results: For Titanium, Zirconia, and PEEK abutments, the mean fracture resistance (±standard deviation) was 727±31 N, 516±21 N, and 289±23 N, respectively. A substantial difference in fracture resistance was found between the various abutment materials according to the one-way ANOVA (p<.001). Zirconia showed much stronger fracture resistance than PEEK (p <0.05) and Titanium abutments demonstrated significantly higher resistance than both Zirconia and PEEK (p <0.01), according to post-hoc tests. Conclusion: The type of the material affects the fracture resistance and fracture pattern of the implant abutment. Titanium, Zirconia, and PEEK abutments show different fracture resistance. Titanium requires more force to be fractured while polyether ether ketone shows less required force. This may affect the prosthetic screw fracture and affect the longevity of the implant.

Background: The aim of this study was to investigate the influence of abutment material, alveolar bone density, and occlusal forces on stress distribution around maxillary anterior implants. Materials and Methods: An in‑vitro study was conducted. The maxillary anterior implant was modeled using a three‑dimensional finite element model in D2 and D3 bones with three different abutment materials: titanium, Zirconia, and poly‑ether‑ether ketone (PEEK). Von Mises stress was evaluated after the application of vertical and oblique loads of 100 N, 175 N, and 250 N. Statistical analysis was done by Friedman–Wilcoxon signed‑rank test, Mann–Whitney U test, and Kruskal– Wallis test. The probability value <0. 05 is considered a significant level. Results: Stress distribution around D3 bone was higher than D2 bone in all the abutment materials with greater values seen in oblique load than vertical load with insignificant difference (P > 0. 05). Statistically insignificant stress values were seen greater in PEEK than titanium or Zirconia abutment (P > 0. 05). A statistically significant difference was observed between 100 N and 175 N of load (P < 0. 05). Conclusion: PEEK, Zirconia, and titanium as abutment material in the anterior region showed similar properties. The stress on the bone was proportionately increased during the vertical and oblique loads suggesting the influence of mechanical load in crestal bone loss rather than the type of abutment material

Background and Aim: Oral bacteria can proliferate in the implant-abutment interface (IAI) and cause inflammation in the peri-implant tissues and adjacent bone. This study aimed to assess the effect of Zirconia and titanium abutments on the microleakage of the IAI under oblique cyclic loading conditions. Materials and Methods: In this in-vitro study, 12 implant-abutment assemblies with Zirconia and titanium abutments, in two groups of six, were vertically mounted inside resin blocks modified with autopolymerizing polyester base. The specimens were subjected to 75N oblique cyclic loading at an angle of 30± 2° to the longitudinal axis of the implant at a frequency of 1 Hz at 500, 000 cycles, which is equivalent to 20 months of human masticatory force. Fuchsine solution was used to evaluate the microleakage. To examine the penetration of fuchsine into the IAI, the fixtures were cut from the middle using a cutting machine. Then, the amount of fuchsine penetration in each of the samples was measured with a stereomicroscope at ×75 magnification at three points in each semicircle (cut implant), and the average of these six points was recorded as microleakage (μ m). T-test was used to compare the microleakage after load with the significance level set at 0. 05. Result: The microleakage rate after cyclic loading was 66. 08± 11. 66 μ m in Zirconia abutments and 39. 17± 10. 65 μ m in titanium abutments, which was significantly higher with Zirconia abutments (P=0. 002). Conclusion: Microleakage after oblique cyclic loading varies depending on the type of abutment. Titanium abutments showed significantly less microleakage than Zirconia abutments.

Background and Aim: Microgap in the implant-abutment interface is one of the main challenges in the treatment of two-piece implants. This study aimed to investigate the effect of two types of abutments (Zirconia and titanium) on microgap at implant-abutment interface area under oblique cyclic loading in vitro. Methods and Materials In this in vitro study, 12 implant-abutment assemblies were used, each containing six sets with either Zirconia or titanium abutments and vertically mounted in the modified resin blocks of auto-polymerized polyester base. The specimens were then subjected to oblique cyclic loading of 75 N at a 30 ± 2 degrees angle to the longitudinal axis of the implant with a frequency of 1 Hz in 500, 000 cycles, equivalent to 20 months of human mastication. For the microgap analysis, direct observation from the top was used with a scanning electron microscopy (SEM) with a magnification of 5000×. Statistical analysis was used to compare the microgap before and after the application of loading with the paired t-test. Results: The amount of microgap before force application in the titanium abutment group was (2. 6± 0. 7) significantly higher than the Zirconia abutments (1. 9± 0. 5) (P = 0. 033). The dimension of the microgap in the titanium abutment group significantly decreased following cyclic loading (P = 0. 047), but in the Zirconia group showed a significant increase (P = 0. 035). Finally, the dimension of the microgap following oblique cyclic loading in the titanium abutment group (2. 0± 0. 8) was not significantly different with the Zirconia abutments (2. 7± 0. 9) (P = 0. 262). Conclusion: The difference of microgap after oblique cyclic loading between two types of titanium abutment and zirconium abutment is not significant, and both are clinically acceptable.

Background and aim: Oral microbiota could proliferate the microspace between the implant and abutment, thereby cause inflammation in the peri-implant tissues and adjacent bone. This study aimed to investigate the effect of two types of abutments (Zirconia and titanium) on microleakage at implant-abutment interface area under oblique cyclic loading in vitro. Materials and methods: In this in vitro study, 12 implant-abutment assemblies were used, each containing six sets with either Zirconia or titanium abutments and vertically mounted in the modified resin blocks of autopolymerized polyester base. The specimens were then subjected to oblique cyclic loading of 75 N at a 30 ± 2 degrees angle to the longitudinal axis of the implant with a frequency of 1 Hz in 500, 000 cycles, equivalent to 20 months of human mastication. To determine the penetration of fuchsine into the implant-abutment interface, the implants were cut by cutting machine from the middle. Then, the rate of penetration of fuchsine in each sample was measured by a stereomicroscope with a magnification of 75 × at three points of each semicircle, and the average of these six points was recorded as a microleakage. For comparison of the microleakage after loading, t test was used. All tests were performed in SPSS ver. 22 software and a significant level of 0. 05 was considered. Results: The amount of microleakage after oblique cyclic loadingwas statistically significantly higher in the Zirconia abutments (66. 08± 11. 66) compared to the titanium abutments (39. 17± 10. 65)following force application (P = 0. 002). Conclusion: The microleakage following oblique cyclic loading is different depending on the type of abutment, so that the titanium abutments showed significantly less microleakage than the Zirconia abutments.

Background and Aims: In response to esthetic demand and use of Zirconia abutments; detection of implant abutment connection misfit is so important. The purpose of this study was to evaluate the sensitivity and specificity of radiographic images in the detection of abutment-implant connection misfit in Zirconia and titanium abutments of three different implant connections.Materials and Methods: One regular implant fixture of Branemark, Noble active and Replace systems were mount in acrylic models. Two pieces titanium and zirconium abutments were attached to the implants, once with correct adaptation and once with 0.5 mm spacer. Digital radiographic images were taken of 12 created states with zero degree vertical and horizontal inclination and evaluated by 10 specialists in implant treatment in two different time penods. Data were analyzed using Kappa analysis.Results: Interclass Correlation Coefficients (ICC) of the agreement of answers in the first and second times were 97.4 and 97.5, respectively (P<0.001). Sensitivity of detecting gap in all groups was acceptable (95-100%) except titanium abutment in Noble active which was the lowest value (35%). Specificity of all groups were acceptable (80-95%) except Zirconia abutments in Noble active and Replace with 45% and 30% values, respectively, and titanium abutments in Branemark had the highest value (95%).Conclusion: The sensitivity of radiographic images in detection of abutment-implant connection misfit only in Noble active with titanium abutment was not acceptable. Specificity of radiographic images in the absence of gap in titanium abutments was more favorable.