Aim-The impact of orthodontic force application on dental pulp tissue lacks conclusive evidence. This study aimed to compare the early and delayed histological effects of intrusive forces on the dental pulp of both adolescents and adults. Materials and methods- In this investigation, all participants necessitated the extraction of a mandibular premolar for orthodontic purposes. The participants were then categorized into two age groups: adolescents aged 12–18 years (n = 15) and adults aged 25–35 years (n = 15). Results- No significant differences were observed in histological parameters between the intrusive and control groups at both the 1-week and 4-weeks marks after intrusion in both adolescents and adults. Conclusions-Applying a mild orthodontic intrusive force to closed apex teeth does not result in significant histological changes in both adolescents and adults. Nevertheless, it becomes evident that inflammatory-related pulpal histological changes tend to be more pronounced in adults after one month of intrusion. Keywords- premolar, intrusion, pulp