Journal of Medicinal Plants Research Vol. 4(14), pp. 1446-1454, 18 July, 2010 Available online at http://www.academicjournals.org/JMPR DOI: 10.5897/JMPR10.198 ISSN 1996-0875 ©2010 Academic Journals Full Length Research Paper Effect of mouth wash extracted from Salvadora persica (Miswak) on dental plaque formation: A clinical trail Fouad Hussein Al-Bayaty 1 *, Aiman Hamad AI-Koubaisi 2 , Nidhal Abdul Wahid Ali 3 and Mahmood Ameen Abdulla 4 1 Department of Restorative Dentistry, College of Dentistry, University Teknologi MARA Shah Alam, Malaysia. 2 Faculty of Dentistry, Baghdad University, Baghdad, Iraq. 3 Faculty of Dentistry, Al Mustansrya University, Mustansrya, Iraq. 4 Department of Molecular Medicine, Faculty of Medicine, University Malaya, Malaysia. Accepted 17 June, 2010 Chewing sticks or Miswak are used for teeth cleaning in many parts of the world, these Miswaks are believed to contain chemical substances which inhibit plaque formation and gingivitis. In the present study, Salvadora persica (Miswak) was extracted with 60% ethanol and was examined for its toxic effect, assessed its antibacterial activity and evaluated clinically for its effect on dental plaque formation. A 4 day plaque regrowth, double - blind, crossover design was used in which 10 dental students volunteers were rendered plaque free (0.3), ceased tooth cleaning, then, asked to rinse twice daily for 1.5 min each time with 10 ml of chlorhexidine 0.2% mouth rinse and three times daily for 1.5 min each time with 10 ml of S. persica 10% solution and placebo mouth rinse. On day five, plaque was scored by the plaque index system (PLI). A wash out period of 2 days was allowed in which the volunteers returned to self- performed plaque control, then a new test period was initiated. Statistical analysis showed that the mean PLI score were 1.48 for S. persica mouth rinse, 0.48 for chlorhexidine and 2.07 for placebo mouth rinse. Acute toxicity test revealed no mortality among the experimental animals which is an indication that S. persica crude extract solution is well tolerated, disk diffusion test showed a marked antibacterial effect in vitro and this effect is concentration dependent, had an effect in in vivo, but this effect cannot be considered absolute. Key words: Mouthwash, Miswak, dental plaque. INTRODUCTION Supragingival plaque control is largely the responsibility of the individual, using tooth brushes and interdental cleaning devices, however; mechanical plaque era- dication is considered for most as time consuming, requires above average of motivation, skill and is more difficult for handicapped people (Lindhe, 2003). Also, the prevalence of gingivitis, from young age in all population, and the occurrence or recurrence of periodontal disease is high (Brown et al., 1996). These observations suggest that mechanical cleaning alone by a considerable pro- portion of individuals is insufficiently good to maintain gingival health and, in the susceptible individual, to prevent *Corresponding author. E-mail: drfouadhm@yahoo.com. Tel: 00603-55435818. Fax: 00603-55435803. periodontal disease occurrence and progression or recurrence. This supports the concept of employing agents to control plaque and require minimal cooperation and skill in their use This is the concept, which underlies, chemical supra gingival plaque control. A number of chemical agents which have antiseptic or antimicrobial action have been used, with variable success, to inhibit supragingival plaque formation and the development of gingivitis. Among these are; phenolic compounds, Bis-biguanidaes, Pyrimidines, Quaternary ammnium compounds, Oxygenating agents, halogens, heavy metal salts (Mandel, 1988). And among these agents, chlorhexidine is, thus far, the most studied and effective antiseptic for plaque inhibition and prevention of gingivitis when used twice daily as mouth rinse (Ribeiro et al., 2007). But in oral use as a mouth rinse chlorhexidine