## 4 Discussion
### Skin and Lip Rejuvenation  
[PERSON] et al. [27] aimed to assess the safety and effectiveness of using hyaluronic acid (HA) for enhancing the lips' appearance. The researchers discussed the process of injecting HA into the lips, explored various HA formulations available, and examined the potential benefits and risks associated with this treatment. Furthermore, the study compared the attractiveness of lips with different thicknesses after undergoing hyaluronic acid fillers, as perceived by dental surgeons, facial harmonization specialists, and laypersons. The results demonstrated that HA injections were a safe and effective method for rejuvenating the lips. The treatment significantly improved lip volume, contour, and overall appearance, with a low risk of adverse effects. [PERSON] et al. [62], [PERSON] et al. [63], and [PERSON] et al. [64] also corroborated the findings reported by [PERSON] et al. [27], suggesting that HA injections can be a valuable tool to improve smile attractiveness that is affected by the lips, gums, and teeth and increase patient satisfaction with their facial aesthetics with the result that lip augmentation has become increasingly popular in recent years as a reflection of cultural trends that emphasize youth and beauty. However, it is poorly understood whether lip thickness before filling may favor greater attractiveness after the procedure, so the authors studied this phenomenon of interest.  
[PERSON] [37] examines the impact of aging on lip structure and its implications for oral aesthetics. The article discusses various treatment options to enhance the appearance of aging lips, including injectable lip augmentation fillers, lip lift surgeries, and maxillofacial surgery. Injectable fillers are highlighted as a minimally invasive technique that can effectively improve the look of the lips and period region. The study also mentions using fillers to address concerns like nasolabbial folds and marionette lines, which are common aesthetic issues for patients. Furthermore, it refers to several recent studies that explore different techniques and therapeutic approaches to rejuvenate the lips and period region [26; 65; 66].  
The study by [PERSON] et al. [10] explored the effectiveness of HA in treating facial aging in fully edentulous patients. The research involved 45 randomly assigned participants to receive either HA injections in the facial region (intervention group) or placebo injections (control group). The findings demonstrated that HA injections successfully enhanced facial wrinkles, skin hydration, and overall appearance in fully edentulous patients. The intervention group experienced significant improvements in the severity of facial wrinkles and skin hydration level compared to the control group. Other studies, including those published by [PERSON] [67], [PERSON] et al. [68], [PERSON] et al. [69], and [PERSON] et al. [70], also supported the use of HA injections in edentulous patients, emphasizing its safety and tolerability without any serious adverse events reported. The authors of these studies suggested that HA injections could serve as a safe and effective alternative or complementary treatment to traditional dental prostheses for enhancing oral and facial health in fully edentulous patients. Furthermore, dentistry has begun exploring the use of HA as an adjuvant in the healing processes following titanium implant insertion, utilizing its advantageous chemical properties such as hygroscopicity, viscoelasticity, space-fillingability, bacteriostatic effect, anti-edema effect, antioxidant effect, biocompatibility, and non-immunogenicity.