ABSTRACT
PURPOSE: The purpose of this study was to evaluate the fracture strength of straight and angled zirconia abutments for internal hex and external hex implants. MATERIALS AND METHODS: Twenty internal hex implants and 20 external hex implants were prepared. The prefabricated straight zirconia abutments and 17-degree-angled zirconia abutments were connected to those 40 implants. The specimens were classified into 4 groups depending on the connection type and abutment angulation; internal hex implant/straight abutment, group INS; internal hex implant/angled abutment, group INA; external hex implant/straight abutment, group EXS; external hex implant/angled abutment, group EXA. All specimens were loaded at a 30-degree angle with a crosshead speed of 1 mm/min using universal testing machine. The fracture loads were analyzed using 2-way ANOVA and independent t-test (α= .05). RESULTS: The mean fracture load for INS was 955.91 N, 933.65 N for INA, 1267.20 N for EXS, and 1405.93 N for EXA. External hex implant showed a significantly higher fracture load, as compared to internal hex implant (P < .001). No significant differences in fracture loads were observed between the straight and angled abutment in internal hex implants (P = .747) and external hex implants (P = .222). Internal hexes of abutments were fractured horizontally in internal connection implants, while lingual cervical neck portions were fractured in external connection implants. CONCLUSION: The zirconia abutments with external hex implants showed significantly higher fracture strength than those with internal hex implants. However there was no difference in fracture strength between the straight and 17-degree-angled zirconia abutment connected to both implant systems.
Subject(s)
NeckABSTRACT
It is rightly said, “implant dentistry is a prosthodontic discipline that happens to have a surgical component.” Even though the most recommended concept is restoration driven implant placement, the anatomical features of the bone may not allow for the ideal placement of the implant. One of the complications occurring during the implant placement is malalignment or placement in less ideal positions. Various techniques have been discussed in the literature to describe the correction of this malpositioning of the implants. These methods encompass both surgical and prosthodontic aspects. Where in surgical methods are more of invasive for an osseointegrated implant, prosthodontic methods offer better results with less complicated procedures with the use of customized or angulated abutments. This review gives an insight into the various options of abutment available for the restoration of the angulated implants.
ABSTRACT
Objective:To study the influences of angled abutments connected with small diameter implants in anterior maxilla restora-tion.Methods:Simulation models of angled abutment with small diameter restoration in anterior maxilla were established,the biome-chanical properties of the models were studied by finite element method(FEM)analysis.Results:Following the increase of the abut-ment angle,the stress and strain of all parts increased linearly and more concentrated,while appropriate prosthetic crown could share some load.Cortical bone elastic deformation exceeded the threshold when the abutment angle was bigger than 8 °.Conclusion:With abutment angle increase,stresses and strains will increase and will be more concentrated,which is unfavorable for load conduction.Ap-propriate crown can reduce the adverse effects of angled abutment.Angled abutment should not be used for d 3.5 implant.
ABSTRACT
Objective To explore the effects of angled abutments on the anterior maxilla implant restoration. Methods We analyzed the biomechanical properties of implants of different sizes (Φ3.5 mm,4.0 mm and 4.5 mm in diameter;L11.5 mm and L13 mm in length)after connecting different angled abutments (0°,10°,20°,and 30°) using finite element method.Results The stresses and strains of loading parts of restorations increased and their distribution became more concentrated as the angle of abutment increased.Cortical bone of Φ3 .5 implants with smaller angle (10°or less)andΦ4.0 implants with abutments had the risk of overpassing the bone elastic threshold when the angle approached 30°.However,the cortical bone elastic deformation was within a safe range at all angles inΦ4.5 group.Conclusion We should consider the diameter of the implant when selecting angled abutments.The angled abutments are not suitable for small diameter implants.The bite force should be under control when needed. The larger angled abutments can be applied in the standard and major diameter implants and it is necessary to avoid occlusal overloading.