18 February 2022

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Phoenix analysis: reanalysis of old studies in dentistry

Authors: M. Nieri, U. Pagliaro, L. Franchi, C. Clauser

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PURPOSE. This study explores an inexpensive method of obtaining useful information by reprocessing individual patient data reported in old clinical studies by means of secondary analysis. 

MATERIALS AND METHODS. Three areas of interest in dental research were chosen (gnathology, endodontics, and periodontology). A manual search was conducted on Oral Surgery, Oral Medicine, and Oral Pathology from 1960 to 1970. Only articles reporting individual patient data (IPD) and published at least 50 years ago were considered. One article concerning a controversial topic in each area was selected. Three old articles were chosen to be subjected to new statistical analyses not available at the time of the original publication. Specifically, the IPD from each selected study was entered into an electronic database for further analysis, performed via the appropriate current statistical techniques.

RESULTS. The new analyses confirmed the conclusions drawn by the original authors were correct in some cases, while contradicting them in others. In particular, a lack of relationship between pulp alterations and periodontitis was confirmed, as was hypothesis that the roots of immature teeth grow after transplantation. However, a lack of correlation between maximum mouth opening and condyle location was disproved, as was the notion of intra-individual variation in pulp morphology. 

CONCLUSIONS. Phoenix analysis is a useful and inexpensive method of updating interpretations of old dental literature, and can provide a springboard for further research.

Didascalia

Logistic regression of the completely anterior position of the right condyle at maximum mouth opening.

Logit Right Ant = -6.04 + 1.40 Mouth Op

Mouth Op is the maximum mouth opening in cm. Right Ant is 1 when the right condyle is completely anterior to the articular eminence, otherwise it is zero. The logistic regression line gives the estimated probability of having the right condyle completely anterior to the articular eminence at the various maximum mouth openings expressed in cm.