A Comparison of Stability Between Conventional and Immediate Dental Implant Systems

Abstract Immediate dental implant placement has become increasingly popular as it decreases treatment time and surgical appointments for patients. However, the question remains as to whether stability of the immediate dental implant system is comparable to that of the conventional dental implant system. The objective of this study was to compare the biological and mechanical stability between conventional and immediate dental implant systems in an animal model. Four male beagle dogs (weighing 10-12 kg) were used for this study following Institutional Animal Care and Use Committee (IACUC) approval. Each dog underwent extraction of bilateral first molars (M1). After 10 weeks of a post-extraction healing period, 2 premolars were extracted bilaterally from each dog (P3 and P4). A dental implant was placed at the first molar site (Con). The same type of dental implant was placed into the mesial and distal root of P3 as well as the distal root of P4 immediately after extraction (Imm). An implant stability quotient (ISQ) was measured at the time of implantation and again at euthanasia, which occurred at 3 or 6 weeks of post implantation. Alizarin red and calcein green florescent bone labels were injected to qualitatively evaluate newly formed bone at 2 and 4 weeks after implantation, respectively. Micro-computed tomography (micro CT) was obtained on dissected implant-alveolar bone constructs. The constructs were then sectioned in a buccolingual direction and polished for nanoindentation. Nanoindentation was conducted to measure the elastic modulus (E). A total of 863 indentations were performed at 3x20 array of locations with 30m between indentation sites up to 600m from the implant surface. A paired t-tests was used to compare ISQ values between Con and Imm groups and a mixed model analysis of variance was used for comparison of nanoindentation values, with a significance of P < .05. ISQ values were not significantly different between Con and Imm groups at 0, 3, and 6 weeks after implantation (P >.078). Micro-CT images demonstrated a better bone to implant contact ratio for the Con group compared to the Imm group. Elastic moduli were significantly higher for the Imm group at both 3 and 6 weeks of post-implantation (10.5 ± 81.7 GPa and 13.32 ± 3.29 GPa, respectively) than those for the Con group (6.01 ± 2.22 GPa and 10.23 ± 1.85 GPa, respectively) (P < .001). Both the Con and Imm groups showed a significant progressive increase in E values from 3 to 6 weeks after implantation (P < .034). In conclusion, the Imm group had less quantity but higher quality of interfacial bone compared to the Con group, which provides a comparable stability between the Imm group and the Con group. References 1. Javed, F., et al., Role of primary stability for successful osseointegration of dental implants: Factors of influence and evaluation. Interv Med Appl Sci, 2013. 5(4): p. 162-7. 2. Kim, D.G., et al., Mechanical properties of bone tissues surrounding dental implant systems with different treatments and healing periods. Clin Oral Investig, 2016. 20(8): p. 2211-2220.