The endoplasmic reticulum (ER) is a major storage medium for intracellular calcium (Ca²⁺). Changes in ER Ca²⁺ homeostasis can lead to endoplasmic reticulum stress (ER stress), which, in turn, activates the unfolded protein response (UPR). However, the mechanisms involved remain unclear. This paper investigates the pathways involved in ER stress, ER Ca²⁺ homeostasis, Ca²⁺ channels, and related oral diseases. A systematic search of the literature up to April 8, 2025, was performed using PubMed and Google Scholar with specific terms for ER stress, Ca²⁺ homeostasis, and oral disease. The findings are summarized in both graphical and narrative forms. Disruption of ER Ca²⁺ homeostasis leading to ER stress and UPR can cause cellular dysfunction and inflammation in oral tissues. Understanding the relationship between ER Ca²⁺ homeostasis and ER stress in oral diseases could provide new targets for oral disease treatment.

• 왕웨이이(전남대학교 치의학전문대학원 구강악안면병리학교실) | Weiyi Wang (Department of Oral Pathology, School of Dentistry, Chonnam National University)
• 움창영(전남대학교 치의학전문대학원 구강악안면병리학교실) | Chanyong Eum (Department of Oral Pathology, School of Dentistry, Chonnam National University)
• 김옥준(전남대학교 치의학전문대학원 구강악안면병리학교실) | Okjoon Kim (Department of Oral Pathology, School of Dentistry, Chonnam National University) Corresponding author