Commentary

This report follows a well-established approach to the systematic review, with particular regard for clinical and radiological features of a particular lesion. The authors are American diagnostic clinicians (two are oral and maxillofacial radiologists).

In addition to 10 reported cases of MICRR that fulfilled the selection criteria, the authors presented four cases. Seven of the 10 reports were recovered from Medline and three others were discovered upon review of the citation lists of identified reports.

Only three of the 10 reported more than one case. A problem with single case reports is that it is often difficult to determine their frequency as the period over which the search for such cases is often not reported. Handsearching does not appear to have been done, not an uncommon occurrence in dental systematic reviews1 even though, despite its time-consuming and expensive nature, it does enhance the validity of the review.

The apparent great difference in mean age between the sexes is not significant (t, 1.26). The authors revealed that MICRR is an asymptomatic (therefore, occult) progressive condition. They clearly established the clinical differences between MICRR and root caries. The value of this report is that it will prompt the clinician to consider it when presented with root caries on many teeth. This is important as the implied conclusion of this paper is that it is likely that a proportion of MICRR may have been misdiagnosed and treated as root caries. Diagnosis of more cases may make more certain whether such features as speed and progression of the disease, and hormonal abnormalities (whether they have a role to play and, if so, what that role is). This report is a valuable starting point for further work on MICRR.