Clinical Evaluation of the Effect of Nanohydroxyapatite Lozenge on the pH of Dental Plaque

Sunil Mankar,1 Bennett T Amaechi,1 Kannan Kanthaiah,1 Nahid Iftikhar,1 Amos C Obiefuna2 1Department of Comprehensive Dentistry, University of Texas Health San Antonio, San Antonio, Texas, USA; 2ANCOSTAT Statistical Consulting, San Antonio, Texas, USACorrespondence: Bennett T Amaechi, Department of Comprehensive Dentistry, University of Texas Health San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas, 78229-3900, USA, Tel +1 210 567 3185, Email amaechi@uthscsa.eduPurpose: This study investigated the influence of nanohydroxyapatite-containing (nanoHAP) lozenge on plaque pH following sucrose intake.Patients and Methods: Sixteen adult subjects were enrolled in this double-blind crossover study composed of four interventions: (1) 10% w/v sucrose solution, (2) 10% w/v sorbitol solution, (3) nanoHAP lozenge, and (4) 10% w/v sucrose solution challenge followed by nanoHAP lozenge. Following the determination of each subject’s resting plaque pH, the pH was measured at different time intervals from 3 to 30 minutes from the start of intervention, with 7 days interval between the applications of different interventions. The data were analyzed using the analysis of variance and Tukey’s test (α < 0.05).Results: While sorbitol produces no change in plaque pH, nanoHAP-lozenge increased the plaque pH from a baseline of 7.0 ± 0.3 (mean ± sd) to 7.8 ± 0.2 (mean ± sd) within 30 minutes. Sucrose lowered the plaque pH from a baseline of 7.0 ± 0.4 (mean ± sd) to the lowest minimum of 5.1 ± 0.1 (mean ± sd) at the 7th minute, rising above the critical pH of enamel dissolution (5.5) at 12th minute and the baseline pH in more than 30 minutes. With lozenge intervention following sucrose challenge, plaque pH rose to 5.5 in 8 min, and to the baseline pH in 24 min. The cH area (Hydrogen ion concentration area) produced by sucrose (1.82 sq. units) was significantly (p < 0.05) greater than that produced when sucrose was challenged with lozenge (0.48 sq. units).Conclusion: Nanohydroxyapatite-containing lozenge increased plaque pH, reduced plaque pH drop in the presence of sucrose, and facilitated the rapid recovery of plaque pH after sucrose intake.Keywords: dental plaque, nanohydroxyapatite, demineralization, buffering, lozenge