# A Statistical Procedure for Exploring a Skeletal Age-Explicative Tool for Growing Patients
## 4 Discussion  
Orthodontists always face the demanding task of identifying and foreseeing the pubertal growth spurt or recognizing the final phases of skeletal growth and explaining the distance in time from those developmental periods [11,32]. The methods currently used for the estimation of skeletal age require exposing the patients to ionizing radiation. Since children are more sensitive to ionizing radiation due to their high radiosensitivity [33], having a method that allows reducing patients' exposure to ionizing radiation, following the ALARA principle [34], is of great importance. This is in accordance with the implementation of Directive 2013/59/Euratom, which outlines basic safety standards for protection against the dangers arising from exposure to ionizing radiation and repealing directives. Even if the intraoral radiograph provides a mean effective dose of 1.32 (0.60-2.56) \(\mu\)Sv [35], according to the ALARA principle, it would be better to avoid them. This goal should be achievable using the method described in the present research article, because clinicians could obtain the same diagnostic results derived from the radiograph of the second phalanx of the third finger, but using only biometric data and the information given by an OPG, avoiding further radiographic exams. As said in the introduction chapter, another method for assessing skeletal age is the evaluation of the cervical vertebrae maturation method on lateral cephalograms [3]. This method was discarded in the present study because some studies questioned its reliability [36], and because lateral cephalograms--unlike OPGs that are a routinary screening exam--need precise indications to justify their request: this would have been in contrast with the aim of the study of finding an alternative method not relying on additional radiographs. The assessment of skeletal age is of great importance to determine treatment timing in orthodontic clinical practice, even though it is a challenging task because growth spans over a long time and is characterized by several events with complex interactions [34,37,38]. In fact, the majority of orthodontic and orthopedic treatments are time dependent. The literature confirms that the determination of the optimal timing for early orthodontic treatment requires a comprehensive assessment of clinical manifestations, dental age, and skeletal age; therefore, chronological age by itself  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Skeletal Age** & _Odds Ratio_ & _SD_ & \(z\) & _p \textgreater{} 1 \(z\)_1 & \multicolumn{2}{c}{_Confidence Interval 95\%_} \\ \cline{5-7} \  
is not enough [39]. For example, early treatment of skeletal Class II requires identification of the pubertal growth spurt to take advantage of a faster growth; early treatment of maxillary transverse deficiency or skeletal Class III requires identification of early stages of skeletal maturation to take advantage of immature sutures; and adolescent treatment may also require the assessment of some residual growth, which may be expected [40]. It is known that the maximum acceleration of growth that is found in puberty leads to the maturation of primary and secondary sexual characteristics. There are huge differences in the pubertal spurts of girls and boys: they begin earlier in females than in males [1,41,42], and they are accompanied by the development of secondary sexual characteristics [43]. However, those features are not unequivocally related to skeletal age, thus influencing the assessment of skeletal age and consequently the definition of the appropriate treatment timing. For these reasons, finding a reliable variable for skeletal age assessment would be advisable and desirable. In the present research article, different biometric and radiographic variables were analyzed to investigate a method for skeletal age assessment. The simplest variables studied were age and sex. It is known that chronological age is not a reliable explicator of skeletal age [9,16].