I would like to thank Drs Zeyun Tian and Yinqiu Yan for their comments and interest in our research article entitled “Tooth mineralization stages as a diagnostic tool for assessment of skeletal maturity” (Am J Orthod Dentofacial Orthop 2014;145:7-14).
Drs Tian and Yan brought up a few concerns regarding the selection criteria: one concern was that socioeconomic conditions can affect skeletal and dental growth. We appreciate them for sharing with us about the sensitivity of environmental influences on growth and also for providing the reference regarding the same. The subjects included in our study were patients who could afford orthodontic treatment; hence, we believe they were not of very low socioeconomic status. Another concern was that factors like high fluorosis, history of caries, periodontal diseases, central cusp, enamel hypoplasia, and serious diseases of the deciduous teeth could affect tooth mineralization. In my literature search, I was unable to find any substantial evidence that these factors could affect the dental calcification stages of the teeth used to assess dental maturity in our research. I am not sure what my colleagues meant by “serious diseases of deciduous teeth,” but we mentioned in our methodology that the subjects selected had no history of any developmental disturbances affecting growth.
In regard to the discussion of the results that the dental combination stage FEED would be a much shorter period than the first premolar stage E in reality, and yet the results showed a better predictive value for first premolar stage E alone (for identification of the MP3-F stage), this could have arisen because statistical changes are always quantified, and clinical situations are different. When we used the data for statistical analysis for premolar stage E, we actually also included the data of dental combination stages as well (EEDD, EEED, FEDD, FEED, and FEEE); this could have been the reason for the better predictive value of the individual teeth. As with any research project, there is always scope for improvement and future directions to pursue, and we are planning to continue the research to assess which combinations of dental stages would be more specific to identify each skeletal maturation stage.
Regarding the question that canine stage E, first premolar stage D, and second premolar stage D in Table I shows a 100% distribution for the MP3-F stage and yet had a negligible positive likelihood ratio (Table II), clinically this situation can exist. This could be explained as a reflection of the effect of sample size on the results: if you notice that the “n” values in Table I are 3 (canine stage E), 3 (first premolar stage D), and 8 (second premolar stage D), these could have resulted in lower positive likelihood ratios. This limitation of the study was mentioned in the discussion section, and studies with larger samples are needed to verify the diagnostic ability further.
I hope that this response has clarified the concerns about our article, and we very much do appreciate your critical appraisal of our study.