A comparison of dentine wear on prepared tooth sections in vivo using two toothpastes

The measurement of enamel and dentine abrasion by tooth whitening products using an in situ model

OBJECTIVES

To determine the enamel and dentine wear of two whitening toothpastes using an in situ model with ex vivo brushing.

METHODS

Human enamel/dentine (approximately 50:50) blocks (approximately 4 x 4mm) were placed in the upper buccal aspects of full or partial dentures of a group of 25 subjects. Subjects brushed the specimens ex vivo with either a calcium carbonate/perlite or silica containing whitening toothpaste under exaggerated conditions as compared to normal for 30 s, twice per day. Specimens were removed after 4, 8 and 12 weeks and the wear to the enamel and dentine was determined. Enamel wear was determined by change in Knoop indent length and dentine wear was determined from the enamel-dentine step height, measured using optical profilometry.

RESULTS

The mean wear after 12 weeks was for enamel 0.27 and 0.19 microns, and for dentine 34.3 and 61.1 microns, for the calcium carbonate/perlite and silica toothpastes respectively. There were no significant differences between products after 12 weeks. The rate of wear was found to decrease throughout the duration of the study.

CONCLUSION

There were no significant differences between the two whitening toothpastes in terms of enamel and dentine wear after 12 weeks brushing.

A critical comparison of dentifrice abrasion scores on dentine recorded by gravimetric and radiotracer methods

Dentifrice abrasivity on dentine is conventionally ranked by various in vitro methods. The abrasivity of selected dentifrices in Switzerland was ranked in 1985 by the gravimetric and in 1989 by the radiotracer method. Because same-named brands of dentifrices were differently ranked by these methods, Swiss clinicians were unsure which ranking to follow. This paper lists the errors known to occur in both techniques, but unfortunately it is difficult to quantitate the magnitudes of these errors. Consequently, it is impossible to determine which method yields the more reliable results. Thus, researchers should look into the problem of dentifrice abrasion scores and try to formulate tests which could simplify the selection of brand-named dentifrices by clinicians and the consumers.

The rate of cervical abrasion in dental students

Abrasion of the cervical region of teeth has been attributed to mechanical cleaning procedures using dentisfrices containing abrasives of various kinds. In the present study the loss of substance during a 26 month period in the cervical region of the upper left premolars of dental students was measured directly by means of a micrometer. The average rate of abrasion was found to be 0.2 micro per day. No difference was observed between the group using a "non-abrasive" dentifrice and that employing a conventional paste. The risk associated with pulp exposure under the conditions observed is briefly discussed.

Clinical investigation of the effects of dentifrices on dentin wear at the cementoenamel junction

A two-year clinical study was conducted in vivo to assess the dentin wear caused by dentifrices; results were correlated and compared with those obtained in vitro.