Stability of implant-abutment connection in three different systems after fatigue test

Effect of different agents on preload force of dental implants with bio high-performance poly-ether-ether-ketone abutments

Purpose

This study evaluated the influence of different agents such as blood, artificial saliva, and normal saline on preload force of dental implants with bio-high-performance poly-ether-ether-ketone (Bio-HPP) abutments to determine its effect on screw loosening.

Methods

Forty (N = 40) Grade 5 titanium dental implant analog (GM Implant Analog; Neodent, Straumann) with Bio-HPP poly ether-ether ketone (PEEK) abutment and titanium screw was used in the study. The samples were embedded in acrylic split mold. In the control Group C, no agent was added. In the other three groups, blood (B), normal saline (N) and saliva (S) was added in the access cavity of the samples. A sequential torque of 15 Ncm, 20 Ncm, 25 Ncm, 30 Ncm up to 35 Ncm was applied with a digital torque meter (Eclatorq, model: SD-05bn, range:2.5-50 Ncm, torque accuracy: ± 2%cw). Samples were subjected to thermomechanical cyclic loading at 5-550 Celsius for 1000 cycles (Chewing simulator, CS 4.4) to simulate six months of clinical service. Preload was measured as reverse torque value (RTV). Raw data in the form of mean ± standard deviation was documented and subjected to statistical analysis. A one-way ANOVA was performed to contrast the groups. Tukey HSD test was used to determine the multiple comparison assessment (P < 0. 05).

Results

A mean reverse torque value of 35 Ncm ±0.00 was observed in both control and in groups exposed to normal saline (P >.05). Measurements of 33.4 Ncm ±2.51 and 34.8 Ncm ±0.40 were found when exposed to blood and artificial saliva in order (P < .05). When compared with control, exposure to blood showed significant variation in preload (P = .03).

Conclusion

A significant reduction in reverse torque force was observed when titanium implants and Bio-HPP abutments were exposed to blood, suggesting a potential risk of screw loosening (P < .05). In contrast, minimal decrease and no significant change in preload were noted with exposure to saliva and normal saline (P > .05).

Does the index in Morse taper connection affect the abutment stability? An in vitro experimental study

The present study compared three different implant and abutment sets of type Morse taper (MT) connection, with- and without-index, were analyzed regarding their mechanical behavior without and with cyclic load application simulating the masticatory function. Ninety implant and abutment (IA) sets were used in the present study, divided into three groups (n = 30 samples per group): Group A, Ideale solid straight abutment (one piece) without index; Group B, Ideale abutment with an angle of 30-degree (two pieces) without index; Group C, Ideale abutment with an angle of 30-degree (two pieces) with index. The abutment stability quotient (ASQ) values, detorque value and rotation angle were measured before and after the cycling load. Twenty IA sets of each group were submitted to mechanical load at 360,000 cycles. The ASQ without load were 64.7 ± 2.49 for the group A, 60.2 ± 2.64 for the group B, 54.4 ± 3.27 for the group C; With load were 66.1 ± 5.20 for the group A, 58.5 ± 6.14 for the group B, 58.9 ± 2.99 for the group C. Detorque values were lower in groups B and C compared to group A (p < 0.05). In conclusion, the presence of the index did not influence the stability values. However, solid straight abutments (group A) showed higher values of stability compared to groups of angled abutments (groups B and C).