Chlorhexidine (CX) mouthwash is effective against Porphyromonas gingivalis, a periodontal pathogen, but has unwanted side effects. We developed a prototype Nigella Sativa mouthwash (NSM), and measured its anti-microbial effects against P. gingivalis in vitro, as well as assessed its shelf life. We used the agar disc diffusion method and compared inhibition zones with antibiotics as positive controls, and to study acidity, mold, and microbial growth, we used the streaking plate method, and stored the plates in both light and dark conditions, as well as cold (4o C) and room temperature. Data were collected at zero days, seven days, and 14 days. NSM showed the same anti-microbial inhibition level as the strongest positive control. While acidity did not fluctuate measurably, mold and pellet formation were documented in all samples by 14 days, regardless of temperature or light condition. The NSM was an effective anti-microbial against P. gingivalis, but will need to be reformulated to suppress microbial growth in order to serve as a natural alternative to CX.

Background: Calcium hydroxide has been used in dentistry since several decades. It has been used in a number of applications in the field of endodontics such as root resorption, intracanal medicament, and root canal sealers. Although this material exhibits several advantages, it also has some limitations. Objectives: To review the role of calcium hydroxide in the field of endodontics, focusing on its mechanism of action, antimicrobial effects, different applications, cytotoxicity or biocompatibility, and its removal from the root canals. Materials and Methods: An electronic search was done using different databases. Out of 2,664 articles, only 33 articles have been selected to be included in this review because they are directly related to the topic and matched the inclusion criteria of this review: “Language: English” and “Year: 2000-2016”. Results: The antimicrobial effect of calcium hydroxide is controversial. Although some studies supported the effectiveness of calcium hydroxide against some bacteria others reported its limitation against fungal infection. Calcium hydroxide can be used effectively as intracanal medicament, root canal sealer, in weeping canals, for perforation management and root resorption. Conclusions: Despite the limitation of antimicrobial activity of calcium hydroxide, it is used effectively in a number of treatment modalities in endodontics. Due to its biological and therapeutical properties, calcium hydroxide is the material of choice for all pulp therapy. However, when using calcium hydroxide as a dressing material in root canal treatment caution should be taken to prevent the overextension of the paste beyond the tooth apex and avoid the harmful side effects.