In dentistry, particularly in orthodontics, dental age estimation (DAE) combined with skeletal age assists the clinician in providing a proper diagnosis and ideal treatment timing (Diz et al., 2011). Dental age (DA) may be assessed by the dental eruption stage or by the mineralization stage of teeth and tooth buds. However, the influences for timing and sequence of dental eruption may occur due to localized conditions such as crowding, ankylosis, retention of primary teeth, extraction, dental trauma, and cysts. Furthermore, some systemic conditions (prematurity, nutrition, metabolic dysfunction, anaemia, celiac disease) and genetic (Apert syndrome, Down syndrome [DS]) are associated with delayed tooth eruption (Suri et al., 2004).

The radiological evaluation of the tooth mineralization process can be assessed during calcification stages and is less affected by environmental factors and pathological alterations, making it a more reliable method in children than DAE based on dental eruption (Willems, 2001). Various radiographic assessment approaches for the DA have been proposed, focused on either the qualitative component of tooth calcification or the morphology of developing tooth (Demirjian and Goldstein, 1976, Demirjian et al., 1973, Haavikko, 1970, Nolla, 1952)

Age is one of the main characteristics of the biological profile of an individual. When an individual's age is unknown, age assessment has become a mandatory procedure, especially during a court of law ruling or forensic identification (Mohd Yusof et al., 2017, de Oliveira et al., 2012). The establishment of an individual's chronological age (CA) is done by utilizing psychological assessment and medical assessment. These procedures try to estimate the age by converting age-related biological markers to CA. The term "estimation" defines precisely the actual limits related to this expertise (Pinchi et al., (2018)].

The estimation of biological age is through the identification of growth and development milestone indicators within various biological systems of an individual, such as skeletal maturity (skeletal age), body height and weight (morphological age), sexual development (sexual age), and dental development or eruption (DA) (Cunha et al., 2009). It is much easier to estimate the age before the completion of the maturation process of the main parameters for the estimation, such as ossification of the wrist and the second molar root apex (which is around 16 years). Once the child reaches adulthood, the examined markers only serve as a lower limit for their likely CA based on population norm (Pinchi et al., 2018).

Chromosomal disorders and syndromes caused by numerical and structural abnormalities in the chromosomes may present with or without craniofacial and oral manifestation, such as dental agenesis or disturbance in tooth eruption (Pinchi et al., 2018). However, few studies reported in the literature on the impact of these syndromic affections on dental maturation in individuals with a syndromic condition. Some studies revealed overestimation (OE), underestimation (UE), and even no statistical difference in DA estimation between syndromic and healthy individuals using various dental age assessment methods.

Despite the potential impact of genetic and chromosomal changes on oral growth, this systematic review and network meta-analysis aim to investigate the accurate DA estimation method for children with the chromosomal syndrome and evaluate the significant applicability of available DA estimation methods in determining delayed or accelerated age for children with the chromosomal syndrome.