Objectives: The purpose of this study was to determine prevalence and severity of dentin hypersensitivity (DH) and which teeth are most affected in 18-28 year-olds in Ho Chi Minh City, Vietnam.
Methods: Previous studies showed the DH prevalence result of about 30%, so 30% was used as expected prevalence in this formula to calculate the sample size:
N ≥ Z21-α/2*p*(1-p)/d2
P= 0.3
Z2= 1.962
Confidence level at 95%, so d= 0.05
Hence: N ≥ 323
In this study, 500 students were randomly chosen from the list of students aged 18-28 enrolled at the UMP at HoChiMinh city. All subjects were explained about the investigation and gave informed consent (IC) before participating in. Inclusion criteria were based on Gillam et al. (2002) and modified slightly. Subjects and teeth with any of the followings were excluded: Orthodontic appliances; disease requiring analgesic drugs, tranquillizers or mood-altering medication; extended plaque or tartar; root-filled or crowned teeth; abutment teeth for dentures and bridges; teeth with restorations interfering with DH evaluation or suspected to have inflammation.
All were examined by 5 calibrated examiners. Each subject was evaluated by 2 methods (sharp dental probe and blast of cold air). Degree of DH was scored from 0-4. Chi-square test and One-Way ANOVA were used for statistical analysis.
Results: 36.2% of the subjects had DH by probe test, 45% by air test. Most subjects had scores of 1 or 2. Scores of 3 and 4 were rarely found. There were statistically significant differences in DH between females and males as well as between older and younger subjects (p < 0.05). Premolars were the most frequently affected, with prevalence of DH from 23.4% to 27.6%, while molars were the least with a prevalence from 11.0% to 12.6%.
Conclusions: The prevalence of DH in 18-28 year-olds in HoChiMinh city was moderate. Premolars were the teeth most affected with DH while molars were the least.