Use of multiple sensitivity measurements and log it statistical analysis to assess the effectiveness of a potassium- citrate-containing dentifrice in reducing dentinal hypersensitivity R. Chesters', H. W. Kaufman^ M. S. Wolff^, E. Huntington' and I. Kleinberg^ 'Unilever Dental Research, Porl Sunlight Laboratory, Merseyside, UK; ^Slate University of New York at Stony Brook, Long Island, New York, USA Chesicrs R, Kaufman HW. Wolff MS, Huntington E and Kleinberg I: Use of multiple sensitivity measurements and togit statistical analysis to assess the effec- tiveness of a potassium-citrate-conlaining dentifrice in reducing dentinal hypersensi- tivity. J Clin Periodontol 1992; 19: 256-261. Abstract. A potassium citrate-SMFP containing dentifrice was tested in a double-blind 8-week clinical trial on subjects with a history of dentinal hypersensi- tivity. A dentifrice containing SMFP but no potassium salt was used as the controi and a 2nd test dentifrice containing potassium nitrate-SMFP was assessed at the same time. The sensitivity of the subjects was evaiuated at 0, 3 and 8 weeks using eiectricai and tactiie methods pius a 1-s air blast. The sensitivity scores for eacii subject at each examination were summarised as a proportion of the examined teeth deemed sensitive. Assessment of any effects of the dentifrices was via an anaiysis of covariance of tlie iogit transformation of these pro- portions with the baseiine vaiue as the covariate. The use of this novel method of analysis had the advantage of taking into account ciianges in sensitivity of ail of the teeth, both sensitive and non-sensitive, since electrical measurements indi- cated effects on both. Of the originai i20 subjects, ill compieted the trial and the 3 dentifrice groups remained weii baianced for age, sex and sensitivity. Ail 3 dentifrice groups showed statistically significant reductions in sensitivity over the 8 weeks. However, the potassium citrate-SMFP dentifrice was significantiy more elTective than either ihe controi SMFP dentifrice, or the potassium nitrate- SMFP dentifrice, at reducing sensitivity after 3 weeks, and this difference pius further sensitivity reduction with all 3 dentifrices was observed after 8 weeks. Key words: dentinal hypersensitivity; potas- sium citrate; potassium nitrate; sodium mono- fluorophosphate. Accepted for publication 6 February 1991 Dentinal hypersensitivity is a relatively common problem experienced by tiie adult dentate population. Graf & Gal- asse (i977) reported that as many as i in 7 subjects attending for dentai treat- ment suffered in i977 from tiie probiem. For the purposes of this study, dentinai iiypersensitivity was defmed as tooth pain resulting from thermal, tactile or osmotic stimulation and affecting teeth with exposed dentinal tubules. The con- dition is not due to caries, cracked teetii. pulpal abscess or occlusal trauma. This definition is broadiy in iinc with tiie description of dentinai hypersensitivity used by Addy and co-workers in their series of review papers (Doweii & Addy i983, Addy i985, Doweii et ai. i985). Agents for the topical relief of den- tinal hypersensitivity have relied on either blocking the exposed dentinal tu- buies or a direct desensitizing effect on ptiipal nerve fibres for their efficacy (Addy & Doweii i 983). McFail & Ham- rick (1987) have shown that sodium citrate togetiier with sodium fiuoride and pluronic gel can reduce tooth sensi- tivity better than sodium fiuoride alone. A number of potassium salts have been shown to be effective desensitizing agents. For example, potassium nitrate, both by itself (Tarbet et al. i980, i982. i982) and in the presence of sodium monofiuoropiiospiiate (SMFP) (Sil- verman i985) was shown to reduce den- tinal hypersensitivity compared with a non-fluoride containing placebo. More recentiy. Saivato et ai. (i989) demon- strated that the combination of potas- sium chloride and SMFP was effective in reducing sensitivity. The precise mechanism for the efficacy of potassium salts remains to be proved, aithough it has been suggested tiiat the potassium acts directiy on puipal nerve fibres (Kim i986). Methods commoniy used in ciinicai triais designed to test the efficacy of