Estimation of Salivary Bone Specific Alkaline Phosphatase as a Biomarker for Assessing Skeletal Maturity Indicator

Abstract

ABSTRACT Background: Evaluation of skeletal maturation plays a substantial role in selection of orthodontic treatment strategies. Recently, new noninvasive methods of assessing biological mediators have been introduced to assess skeletal maturity. There is a marked rise in the value of these mediators during pubertal growth spurts. When these mediators emerge as the assessment tool for skeletal maturity determination, it can reduce radiation exposure and beneficial to the patient. Hence, the goal of this study is to validate the calculation of salivary alkaline phosphatase (ALP) as a noninvasive skeletal maturity indicator by estimating the Bone Alkaline Phosphatase (B-ALP) level in whole unstimulated saliva at different stages of skeletal maturity and correlating B-ALP level with different stages of skeletal development using cervical vertebral maturation index (CVMI) and hand-wrist MP3 (third finger middle phalanx). Materials and Methods: The test group included 90 subjects aged between 8 and 18 years requiring orthodontic treatment. The salivary samples were collected and examined by ALP kit following the manufacturer’s instructions and assessed using photo-spectrometer at 405 nm. The skeletal age was assessed using handwrist radiographs; skeletal age was determined by modified MP3 staging. Lateral cephalograms of each individual were also collected and tracing done for assessing skeletal age with CVM staging. The collected data were analyzed statistically with analysis of variance for intergroup comparison of ALP levels and Kruskal–Wallis test for intergroup comparison of CVM and MP3 stages. Results and Conclusion: Salivary ALP activity during the peak pubertal period was markedly increased when compared to pre- and post-peak values. Salivary ALP activity was in correlation with the cervical vertebral maturation and MP3 stages showing peak values at the pubertal stages. Thus, salivary B-ALP can serve as a noninvasive method of skeletal maturity assessment as an adjunct to conventional skeletal maturity indicators.