## 4 Discussion  
This study investigated biomechanical factors by analyzing stress and strain applied to implants and surrounding bone according to bone loss and quality. The results showed that the stability of implants was significantly affected by the amount of bone loss and bone quality surrounding them, suggesting that the anatomical and structural characteristics of bone play an important role in implant success and long-term survival. Implant complications are generally classified into biological and technical complications, but in actual clinical practice, complex interactions between human tissue and the mechanical components of the implant occur. Biological problems can cause technical defects, and conversely, technical defects can lead to biological problems, so one problem or defect can escalate into another clinical complication [42]. Since these interactions vary depending on the biological conditions of each patient, it is necessary to understand the biomechanical characteristics of the bone tissue surrounding the implant and comprehensively consider various factors. In particular, the structural characteristics and quality of the bone play an important role in the implant withstanding and dispersing external stress, and if the bone quality is low, stress may be concentrated, and bone loss may accelerate [43]. This may negatively affect the implant's stability and ultimately lead to implant failure. Therefore, to prevent excessive bone loss and identify its causes, it is necessary to analyze various factors that act in clinical practice from various angles [19]. Marginal bone loss of approximately 1.5-2 mm around the implant neck during the first year after implant placement is considered a physiological response, and additional bone loss of less than 0.2 mm per year after that is within the clinically acceptable range and is considered a positive outcome [31]. However, the criteria presented in each study are different and lack consistency [44; 45; 46]. The level of bone loss that can be used to predict implant failure has not been appropriately defined. In this regard, a systematic approach that clearly distinguishes between physiological and pathological loss of marginal bone around implants and closely evaluates continuous bone changes is emphasized. Our results showed that as bone loss around the implant increased, the maximum von Mises stress in the implant fixture and surrounding bone tissue tended to increase, consistent with previous research results showing that marginal bone loss around the implant compromises implant stability. A previous study evaluating the stress distribution during occlusal loading on implant-supported prostheses using different amounts of bone loss and materials demonstrated statistically significant differences in the stresses in all relevant structures when the bone level was reduced by 2 and 4 mm [11]. Another previous study investigating the effect of microthreads on the stress distribution in the bone around implants with different bone levels demonstrated a progressive increase in the stresses  
Figure 5: Distribution and volume fraction of fatigue failure area in cortical and cancellous bone: (**a**) principal strain distribution in low-quality bone; (**b**) volume fraction values according to bone loss. in the bone around implants with increased depth of bone resorption [47]. Additionally, another previous study determining the effect of prosthetic materials and crown/implant (C/I) ratios on short implants with marginal bone resorption demonstrated that the stresses in the implants ranged from 50 to 105 MPa in non-resorbable models, whereas in resorbable models, the values ranged from 168 to 322 MPa [48]. This stress increase phenomenon was observed throughout the entire structure and may be due to the reduced implant support capacity caused by bone loss.