A study of the influence of mouth-breathing in some parameters of unstimulated and stimulated whole saliva of adolescents Rosa M.E. Weiler * , Mauro Fisberg, Alcely S. Barroso, Jose Nicolau, Roberta Simi, Walter L. Siqueira Jr. Federal University, Adolescent Sector, Department of Pediatrics, School of Medicine, S. Paulo, SP 05412-003, Brazil Received 15 July 2005; received in revised form 5 September 2005; accepted 13 September 2005 1. Introduction Reports on the salivary flow rates of mouth-breath- ers are somewhat conflicting. It has been reported International Journal of Pediatric Otorhinolaryngology (2006) 70, 799—805 www.elsevier.com/locate/ijporl KEYWORDS Mouth-breathing; Saliva; Adolescent; Sialic acid; Flow rate Summary Objective: The aim of this study was to analyze some standard parameters of the unstimulated and stimulated whole saliva of mouth-breathers and a control group to determine if these variables present any difference in mouth-breathers compared to control group, since these parameters of saliva can influence the oral health. Methods: Saliva samples were collected from 61 adolescents aged 10—19 years; 30 were mouth-breathers and 31 were nose-breathers. The unstimulated salivary speci- men was collected, followed by collection of the stimulated saliva. Soon after collecting the salivary sample, the flow rate and buffering capacity were determined. The samples were then stored at 80 8C until analysis was performed. The analysis consisted of the determination of protein content and total, free and bound sialic acid levels. Results: No statistically significant difference was observed in the flow rate, buffer- ing capacity, protein content, total and bound sialic acid levels of unstimulated and stimulated saliva, nor in the free sialic acid of stimulated saliva. However, the levels of free sialic acid of the unstimulated saliva were significantly higher in the mouth- breather compared to the control group. Conclusions: Since a higher level of free sialic acid is indicative of an increase in the number of bacteria in saliva, our findings suggest that mouth-breathers retain more bacteria in oral tissues. # 2005 Elsevier Ireland Ltd. All rights reserved. * Corresponding author. Tel.: +55 11 38912546; fax: +55 11 38733158. E-mail address: reid@uol.com.br (Rosa M.E. Weiler). 0165-5876/$ — see front matter # 2005 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijporl.2005.09.008