Stage of skeletal development is one of the important factors affecting orthodontic treatment planning. It has been shown in many studies that the chronological age in relation with the determination of the skeletal maturity and stage may not be accurate [2, 14, 27,28,29].
Various methods have been developed for assessing the stages of the skeletal development. Among many, the most common method is the hand–wrist radiographs because of the number of bones present in which physiological development can be followed [30,31,32]. In addition, it has been suggested by various studies that developmental evaluation can be made using the cephalometric radiographs used in orthodontic treatment planning [10, 11, 13, 14, 33].
Hassel and Farman used cephalometric radiographs to develop their own method (1995) and compared with the Fishman’s method on hand–wrist radiographs. The correlation coefficient between the two methods was found to be 0.89 . In this study, Gilsanz and Ratib method (2005) was preferred for the evaluation of hand–wrist radiographs and, as a result, the correlation coefficient between the hand–wrist radiographs and the cephalometric radiographs was found to be 0.79. Although the correlation coefficients are very close in both studies, the difference may be due to the preferred method.
Kama et al. compared chronological age and skeletal age in the HWR and the CR of 150 male individuals aged 10–18 years. They used the Fishman’s method for skeletal age determination in the HWRs and used a formula that includes the width and height parameters of the 3rd and 4th cervical vertebrae in cephalometric radiographs. They found a correlation value of 0.719 between the two methods . In this study, the correlation coefficient was determined higher than those reported by Kama et al. (0.79).
Flores-Mir et al. examined the hand–wrist and the cephalometric radiographs of 52 females and 27 males to evaluate the development of the skeletal growth and used the Fishman and Baccetti methods, respectively. They found the correlation coefficient between the two techniques as 0.72 . In this study, Gilsanz, Ratib and Hassel-Farman’s methods were used and the correlation coefficient was found to be 0.79. Although the methods used in the study are different, similar high positive results can be evaluated in favor of the fact that all methods are highly reliable.
Uysal et al. examined the hand–wrist radiographs with Hassel and Farman’s method, and the cephalometric radiographs with Bjork Grave and Brown method on a total of 503 subjects (290 females, 213 males) between 5 and 24 ages. The correlation coefficient was found 0.86 for all individuals, 0.88 for girls and 0.78 for boys; in this study, it was found to be 0.79, 0.70 and 0.85, respectively .
Lai et al. evaluated the hand–wrist radiographs with National Taiwan University Hospital Skeletal Maturation Index (NTUH-SMI) and cephalometric radiographs with the Cervical Vertebral Maturation Stage (CVMS) method. Intra-observer reproducibility for the NTUH-SMI and CVMS methods was found to be 90% and 93.3%, respectively . Similarly, intra-observer compliance was 91.2% in the hand–wrist and 59.5% in the cephalometric radiographs in this study. The relative low intra-observer compliance ratio in cephalometric radiographs was attributed to the superposition of bony structures.
Kaplowitz et al. assessed the skeletal age devoplement using 16 hand–wrist radiographs by 5 pediatric endocrinologists and 7 pediatric radiology specialist. They compared Gilsanz and Ratib’s atlas and Greulich–Pyle atlas on HWRs. The study suggested that the use of the digital format of Gilsanz and Ratib atlas should be preferred over the the Greulich–Pyle atlas .
Lin et al. evaluated the hand–wrist radiographs with the Greulich– Pyle atlas and the Gilsanz and Ratib atlas in a total of 648 patients by two radiology experts. Intra-observer adaptation for the Gilsanz and Ratib method was evaluated separately for boys and girls and it was found to be 0.899 and 0.957 for the first researcher and 0.943 and 0.967 for the second researcher, respectively . In this study for all individuals, intra-observer adaptation was 0.912.
Correlation coefficient of females was higher than that of males in several studies [36, 40]. As a result of this study, the correlation coefficient of females was lower than that of males and it was found to be 0.706 and 0.857, respectively (p < 0.05).
Joshi et al. compared 3 methods (HWR, CR and CBCT) in 2012. The study group consisted of 100 patients (51 females and 49 males), age range of 3 to 35. The HWRs were evaluated using Fishman’s method and the CRs and the CBCTs were evaluated using Hassel and Farman’s method. The correlation coefficient between hand–wrist radiographs by Fishman’s method and the cephalometric radiographs by Hassel and Farman’s method was found to be 0.961. Spearman correlation coefficient value among the CRs and the CBCT by Hassel and Farman’s method was found to be 0.975 . It was also concluded that three methods have a statistically positive good relationship for both genders. Spearman’s correlation coefficient values between hand–wrist radiography by the Gilsanz and Ratib atlas and CBCT CVMI; cephalometric radiography CVMI and CBCT CVMI; hand–wrist radiography by Gilsanz and Ratib atlas and cephalometric radiography CVMI were found to be 0.785, 0.875, and 0.791, respectively.
In this study, the distribution of CVMI classifications in the CR and the CBCT was evaluated for all individuals. Determined compliances for CVMI 1, CVMI 2, CVMI 3, CVMI 4, CVMI 5 and CVMI 6 were 100%, 61.1%, 31.3%, 40%, 50% and 61.5%, respectively. There are no studies demonstrating these parameters in the literature.
Although the results of the skeletal development and the chronological age relationship were statistically significant, the numbers of samples were not equal and so further studies are needed with larger sample size.