Biomedical subjects

N X West

Publications and source records attributed to N X West.

22 records · Page 2Linked to original sources

PubMed1997

Dentine hypersensitivity and the placebo response. A comparison of the effect of strontium acetate, potassium nitrate and fluoride toothpastes.

A considerable number of varied agents are apparently effective in the treatment of dentine hypersensitivity. In particular, the literature supports the efficacy of strontium, potassium and fluoride containing toothpastes. This study was a double-blind, randomised, parallel group comparison of three products, namely strontium- and potassium-based desensitising toothpastes both containing fluoride, and a conventional fluoride toothpaste. A total of 131 subjects entered a 4-week wash-in phase using the conventional fluoride toothpaste, of whom 120 entered a 6-week treatment phase. Sensitive teeth were evaluated at wash-in baseline, treatment baseline and after 2 and 6 weeks use of the treatment pastes. Dentine hypersensitivity was assessed with tactile and cold air stimuli together with an overall subjective assessment. Analysis of the findings was performed using non-parametric statistical methods. Of the original 120 subjects, 112 completed the trial. All 3 toothpaste groups showed reductions in sensitivity over the 6 weeks; however, no significant differences were found between the three products at any given time. Interestingly, there was no significant change in sensitivity between wash-in baseline and treatment baseline for the cold air stimulus with the fluoride-only-based paste. However, for the group using the same fluoride toothpaste, there was significant improvement between wash-in baseline and week 6, and treatment baseline and week 6 for this stimulus, suggesting a substantial placebo effect occurred. There is a need for further investigation of a wash-in period and examination of the placebo effect when evaluating dentine hypersensitivity trials.

Acetates↗

PubMedDate not supplied

Ultrasonication as a method to study enamel demineralisation during acid erosion.

The aim of this study was to use ultrasonication as a method to measure subsurface demineralisation of enamel. Polished human enamel samples with surface profiles within +/-0.3 microm were divided into 6 groups of 10 specimens. The groups of specimens were exposed to 0. 3% citric acid (pH 3.2) for 30 min, 1, 2, 3 or 4 h. The depths of the resulting lesions were measured using a profilometer. A control group was stored in water for 4 h. Ultrasonication in water was performed on the specimen groups for 5, 30, 120, 240 and 480 s with profilometric measurements at each time point. The depth of the erosion increased linearly with the exposure time. Most of the additional loss of enamel occurred with the 5-second ultrasonication. The 30-min and 1-hour erosion lesions were further deepened by approximately 1 microm with 5 s of ultrasonication. The 2-, 3- and 4-hour lesions were deepened by 2-4 microm with 5 s of ultrasonication. There were no changes in the control group. It is concluded that ultrasonication removed softened enamel from the surface of the eroded enamel. Ultrasonication together with accurate measurement of lesion depth by profilometry offers a useful method for studying the depth of enamel softening associated with erosion.

Analysis of Variance↗

PubMedDate not supplied

The use of ultrasonication to study remineralisation of eroded enamel.

The aim of this study was to use ultrasonication and profilometry as methods to study de- and remineralisation of citric acid-eroded enamel at different pH values. Seventy-eight polished human enamel samples were divided into three test and three control groups of 13 specimens each. Three specimens of each group were chosen for SEM examination. The samples were exposed to 0.3% citric acid at pH 2.54, 3.2 or 4.5 for 2 h. The depths of the resulting lesions were measured by profilometry. The test groups were placed in artificial saliva and the control groups were stored in saline (0.9% NaCl) for 24 h and new profiles recorded. Finally all specimens were ultrasonicated in water for 5, 30, 120, 240 and 480 s with profilometric measurements at each time point. Ultrasonication of the test groups after remineralisation showed little effect on the lesion depth, whereas the control groups had an enamel loss of 2.1 microm at pH 2.54, 2.9 microm at pH 3.2 and 0.4 microm at pH 4.5 after 30-second ultrasonication. These differences from respective test groups were statistically significant at pH 2.54 and 3.2 but not at pH 4.5. Ultrasonication of control pH 2.54 and 3.2 specimens removed an amorphous covering layer to reveal a flattened surface with prisms outlined by prism boundaries. It can be concluded that remineralisation in artificial saliva stabilises the surface softened enamel against ultrasonication.

Analysis of Variance↗

PubMedDate not supplied

A study in vitro of the abrasive effect of the tongue on enamel and dentine softened by acid erosion.

The palatal aspect of upper anterior teeth appears to be one site of predilection for erosion. This raises the question of whether abrasion of softened enamel and dentine by the tongue has a role in this process. The aim of this study in vitro was to determine whether enamel and dentine specimens licked by the tongue after exposure to acid lost more tissue than when exposed to acid alone. Flat enamel and dentine specimens were prepared from human third molars and taped to expose a window of tissue. Three groups of specimens were exposed to citric acid for 10 min followed by 60 s tongue licking, ultrasonication or immersion in water. Two further groups of enamel specimens were placed in a low erosive drink for 10 min with or without licking. At the end of 5, 10 and 15 treatment cycles tissue loss was measured by profilometry. Enamel loss was significantly greater with licking and ultrasonication compared to water immersion. Dentine loss was greater with licking and ultrasonication compared to water immersion, but differences only reached significance for ultrasonication. The low erosive drink produced one third of the citric acid erosion and licking had no effect. The results suggest that the tongue could exert an abrasive effect on dental tissues softened by erosion, thereby increasing the overall loss of tooth substance.

Adolescent↗