Effect of St. John's Wort Oil and Olive Oil on the Postoperative Complications After Impacted Third Molar Surgery: Randomized, Double-blind Clinical Trial

Chlorhexidine is one of the most commonly used medications after tooth extraction. It exhibits a wide spectrum of antiseptic, bactericidal and bacteriostatic effects. The most common side effect of chlorhexidine is oral discoloration, taste changes and allergic responses. Furthermore, it has been reported that chlorhexidine has cytotoxic effect on gingival fibroblasts, epithelial cells, neutrophils and red blood cells; also shows incremental trend in genotoxicity as the duration of usage is increased. Benzydamine hydrochloride is a nonsteroidal anti-inflammatory drug that elicits anti-inflammatory, analgesic, anesthetic and antimicrobial effects. It is often used in addition to the topical application of chlorhexidine.. However, side effects such as urticaria, erythema, pruritus, photosensitivity, bronchospasm and renal problems can be observed associated with the use of benzydamine.

St. John's Wort (Hypericum perforatum) is a European medicinal plant with a history of more than 2000 years which possessing a variety of important constituents including phloroglucinols (hyperforin and adhyperforin), naphthodianthrones (hypericin and pseudohypericin), xanthones, essential oil, biflavones (biapigenin and amentoflavone), flavonol derivatives and phenolic compounds. The important components of St. John's Wort such as hypericin and hyperforin exert anti-inflammatory, antimicrobial, anticancer effects as well as stimulating tissue growth and differentiation. Hypericin exhibits anti-inflammatory effects by inhibiting the production of interleukin-12; whereas hyperforin reveals this effect by inhibiting the mechanisms of cyclooxygenase 1, 5-lipoxygenase and prostaglandin E2. St. John's Wort oil is extracted by maceration of the hypericum herb in carrier oil, such as virgin olive oil.

The olive oil, a product extracted from the fruit of Olea europaea, exerts also antioxidant and anti-inflammatory effects due to its important contents including oleic acids, phenolic acids, secoiridoids and flavonoids. The oral application of olive oil has been shown to have protective anti-inflammatory effects and accelerated epithelial healing.