Benchtop Evaluations of Healing Abutment Seal Performance

Objectives: Bacteria accumulation at the implant-abutment junction (IAJ) has the potential to lead to marginal bone loss and jeopardize implant survival. Failure of temporary restorative components to prevent leakage would allow microbes to occupy the internal aspect of the implant during the critical healing phase and prior to final restoration. The presence of microgaps at the IAJ can be detected via in vitro seal performance testing. The purpose of this research study was to evaluate seal performance of unloaded healing abutments seated on corresponding implants.
Methods: Matched implants and healing abutments (I1+HA1 and I2+HA2) and a control mismatched components (I-A+HA-B) were evaluated. Short-term perfusion-based leakage (n=5) was measured at controlled screw torque values with dye pumped into the barbed apical end of the implant for 60 s. Long-term dye leakage (n=5) is being evaluated over 28 days. Statistical analysis involves use of one way ANOVA and Tukey’s test with a significance level of a = 0.05.
Results: Short-term seal performance testing evaluated a range of torque values to ensure that all probable clinical scenarios were covered. Our results demonstrated conservation of the IAJ seal in I1+HA1 and I2+HA2, as evidenced by the absence of dye leakage at each torque value. The control, I-A+HA-B, demonstrated observable leakage at each torque value tested (Fig. 1A). To provide a greater challenge to the healing abutment-implant assembly, constructs will be immersed in dye for up to 28 days. For I1+HA1 and I2+HA2, no dye leakage was measured over the first 14 days, while the control, I-A+HA-B, exhibited significant dye accumulation in the internal aspect of the implant system (Fig. 1B).
Conclusions: Sealing the IAJ at all phases of implantation is important to overall implant performance. Short-term seal performance testing demonstrated matched components did not leak dye at torque values encompassing the clinical range. Fourteen day seal performance testing demonstrated matched components had no dye accumulation at the IAJ. The control demonstrated significant leakage in short-and long-term testing; therefore, it is important to use recommended matched components during the healing phase to help maintain implant hygienics.
Note: Pre-clinical results are not indicative of clinical performance.