ORIGINAL ARTICLE Effects of gustatory stimulants of salivary secretion on salivary pH and flow: a randomized controlled trial ADSP da Mata 1 , DN da Silva Marques 1 , JML Silveira 1 , JROF Marques 1 , ET de Melo Campos Felino 2 , NFRPM Guilherme 3 1 Faculdade de Medicina, Denta ´ria da Universidade de Lisboa, Lisbon, Portugal; 2 Universidade Fernando Pessoa – Faculdade de Cieˆncias da Sau ´de, Porto, Portugal; 3 Instituto Superior de Cie ˆncias da Sau ´de Egas Moniz, Monte da Caparica, Portugal OBJECTIVES: To compare salivary pH changes and stimulation efficacy of two different gustatory stimulants of salivary secretion (GSSS). SETTING: Portuguese Dental Faculty Clinic. DESIGN: Double blind randomized controlled trial. SUBJECTS: One hundred and twenty volunteers were randomized to two intervention groups. Sample sized was calculated using an alpha error of 0.05 and a beta of 0.20. MATERIALS AND METHODS: Participants were ran- domly assigned to receive a new gustatory stimulant of secretory secretion containing a weaker malic acid, fluoride and xylitol or a traditionally citric acid-based one. Saliva collection was obtained by established methods at different times. The salivary pH of the samples was determined with a pH meter and a microelectrode. MAIN OUTCOME MEASURES: Salivary pH variations and counts of subjects with pH below 5.5 for over 1 min and stimulated salivary flow were the main outcome measures. RESULTS: Both GSSS significantly stimulated salivary output without significant differences between the two groups. The new gustatory stimulant of salivary secretion presented a risk reduction of 80 ± 10.6% (95% CI) when compared with the traditional one. CONCLUSIONS: Gustatory stimulants of salivary secretion with fluoride, xylitol and lower acid content maintain similar salivary stimulation capacity while reducing significantly the dental erosion predictive potential. Oral Diseases (2009) 15, 220–228 Keywords: gustatory stimulants; saliva; pH; dental erosion; randomized controlled trial Introduction Dental erosion is commonly defined as the chemical wear of the dental hard tissues without the involvement of bacteria (Eccles and Jenkins, 1974). Its aetiology is multifactorial, and the various disease causes are grouped according to acid origin in intrinsic and extrinsic (Gandara and Truelove, 1999). Intrinsic causes include oral cavity exposure to gastric acids due to abnormalities in the gastrointestinal tract (Ismail-Beigi et al, 1970; Eccles, 1978; Pope, 1982; Myllarniemi and Saario, 1985; Pace et al, 2008) or recurrent vomiting as a result of psychological disorders (Hellstrom, 1977; Knewitz and Drisko, 1988). Extrinsic factors include the unusual or abusive consumption of demineralizing acidic foods and beverages (Eccles and Jenkins, 1974; Smith and Knight, 1984; Asher and Read, 1987; Johansson, 2002; Dugmore and Rock, 2004) and some medicines such as aspirin, vitamin C (Eriksson and ngmar-Mansson, 1986; Meurman and Murtomaa, 1986), iron tonics (James and Parfitt, 1953), acidic oral hygiene products or products with calcium chelators, as well as acidic salivary substitutes and salivary flow stimulants as potential erosive products (Zero, 1996). Nowadays, the prevalence of dental erosion is increasing as modern lifestyle and nutrition habits are believed to favour the incidence of the disease (Zero, 1996). There is a strong evidence linking exposure of endogenous and exogenous acids to dental erosion, although it is clear that the clinical manifestations are also modified by biological and behavioural factors. The biological factors related to dental erosion may involve properties and characteristics of saliva, acquired dental pellicle, tooth structure and surrounding soft tissues (Zero, 1996; Lussi et al, 2004). In fact, saliva has been considered as the most important biological factor in dental erosion prevention, due to its ability to act as a protective factor, via acid diluting and buffering, as well as playing an important role in pellicle formation and tooth remineralization (Meurman and Frank, 1991a; Moss, 1998). Therefore, patients with diminished salivary flow have an increased Correspondence: ADSP da Mata, Faculdade de Medicina, Denta´ ria da Universidade de Lisboa, Cidade Universita´ria, 1649-003 Lisbon, Portugal. Tel: +351 217 922 600, Fax: +351 217 957 905, E-mail: admata2@yahoo.com Received 14 October 2008; revised 06 November 2008; accepted 29 December 2008 Oral Diseases (2009) 15, 220–228. doi:10.1111/j.1601-0825.2009.01513.x Ó 2009 John Wiley & Sons A/S All rights reserved http://www.blackwellmunksgaard.com