Introduction: Lactobacillus plantarum (Lp) were found lots in deep dental caries. Lipoteichoic acid (LTA) Lp induces inflammatory response by activation p38 MAPK expression in mitogen-activated protein kinase pathway. The nature and extent of altered inflammatory response are depended on intensity and duration exposure. To verify that duration exposure LTA Lp associated with inflammatory response in dental pulp. Methods: 45 samples of right upper molar of wistar rats were randomly grouping based on the type of injury. Control negative group, control positive group were given mechanically perforated, experimental group were given mechanically perforated and given LTA Lp 10 μg/ml. Observed in 24 h, 48 h, and 72 h and counting the amount of p38 MAPK expression. Results: there is increasing significantly of p38 MAPK expression between 24 h and 72 h. Conclusion: duration exposure LTA Lp associated with inflammatory response in dental pulp characterized by significantly increased of p38 MAPK expression.