# Validation of the Implant Stability Test for Implant Provisional Crowns: An In Vitro Study
## 4 Discussion  
The results of this study showed significant differences between the two groups for all bone quality types. The correlation varied greatly, depending on the quality of the bone. In both groups, the higher the bone quality, the higher the IST value, and the softer the bone, the lower the IST value. The difference between the two groups was a minimum of 4 and a maximum of 7. [PERSON] et al. [15] measured the implant stability quotient (ISQ) of 40 implants in 14 patients at each week from the time of placement up to 4 weeks. The primary stability and ISQ values were 107.2 \(\pm\) 35.6 Ncm (ISQ: 81.9 \(\pm\) 2.0), 74.7 \(\pm\) 14.0 Ncm (ISQ: 81.1 \(\pm\) 1.0), 76.5 \(\pm\) 31.1 Ncm (ISQ: 78.3 \(\pm\) 3.7), and 55.2 \(\pm\) 22.6 Ncm (ISQ: 73.2 \(\pm\) 4.9). These results indicated that the harder the bone quality, the higher the ISQ value, which is consistent with our results. The primary stability was found to vary depending on the bone quality and implant shape [16; 17]. In immediate loading, initial fixation is one of the factors for successful treatment. [PERSON] et al. [18] compared the immediate load and conventional loading of single implants. They reported that the initial fixation for all implants had a torque of \(\geq\)20-45 Ncm, ISQ \(\geq\) 60-65, and there was no significant difference in implant survival and marginal bone volume. [PERSON] et al. [19] placed single implants with immediate loading in 15 patients. They reported that the initial fixation was of more than 32 Ncm, and the 18-year survival rate was 100%. [PERSON] et al. [20] investigated the survival rate of immediately loaded implants placed with 30 Ncm torque. They reported that the implant survival rate was 96.8% based on a review of 589 references. [PERSON] et al. [21] performed all-on-4 implants in 83 patients. They reported a survival rate of 98.3% for 120 implants placed with less than 30 Ncm torque and of 97.5% for 212 implants placed with more than 30 Ncm torque. From these reports, it can be inferred that the initial fixation for immediate loading should have a torque of 30-45 Ncm. A systematic review by [PERSON] et al. [22] reported that immediate loading of 35 Ncm or less is associated with a survival rate of 96% at the 24-month follow-up. Immediate loading has shown good survival rates, allowing surgeons and patients to have a wider choice of treatment options. After immediate loading, the decision of when to place the superstructure is a troublesome issue for the surgeon. If it is performed too early, osseointegration may not be achieved, and if it is performed too late, the temporary crown can fracture and cause an imbalance in occlusion. In addition, peri-implant mucositis or peri-implantitis may occur due to plaque accumulation [23; 24]. [PERSON] et al. [25] reported superstructure placement 6 weeks after implant placement in 50 patients who underwent immediate loading. [PERSON] et al. [26] placed four implants at 35 Ncm or more and performed immediate loading in 20 dedutulous mandibular patients. They reported that the final prosthetic device was placed 3 months after implant placement, with a good 10-year prognosis. [PERSON] et al. [27] performed immediate loading on 18 single-tooth, partial-tooth, and dedutulous patients, and placed the final prosthetic device 4 months after implantation, with good results. [PERSON] et al. [28] performed all-on-4 implant treatment in 23 patients and placed the final prosthetic device 3 months after implant placement. The total number of implants placed was 92, and the 5-year prognosis was 96.6%. [PERSON] et al. [29] placed six implants in 40 dedutulous maxillary patients and performed immediate loading. They reported that the total number of implants placed was 232, the superstructure was in place within 24 weeks of implant placement, and the 5-year survival rate was 93%. Thus, the timing of superstructure placement after immediate loading varies, although it may be related to the