# Three-Dimensional Pulp Volume Analysis in Lip and Palate Cleft Population
## 4 Discussion  
The main goal of the present study was to compare the medium pulpal volume of central incisors in CLP patients and a control group using a 3D radiography technique (CBCT), to understand if CLP patients present significative pulp volume changes compared with healthy patients. The central incisors were chosen for this study since these teeth present with the least internal anatomical variations and due to the fact that it is easier to isolate the pulpal area of a tooth with a single canal [28]. Regarding the evaluation of gender and age within the range of 12 and 19 years, there were no significant differences between control and study groups. In the literature, it is described that the correlation between pulpal volume and age is inverse, meaning that as a person's age increases, the pulpal volume tends to decrease [9; 28]. The results obtained differ from the literature, since a sample with a reduced age range was chosen. This sample made it possible to compare pulp volume between the two studied groups, reducing the risk of bias associated with changes in pulp volume due to age. In this study, it was verified that the pulp volume does not change between groups considering the same chronological age. Regarding the sexual dimorphism of pulp volume, in a general manner males present a larger volume than females. The sexual dimorphism of teeth, analyzed from a genetic point of view, is reported in the literature with the Y chromosome being associated with an increased tooth growth due to a greater development of amelogenesis and dentinogenesis through increased mitotic activity [9; 23; 29; 30]. It should be noted that patients with CLP often present dental anomalies in terms of shape and size associated with the cleft. Embryologically, this is explained by barely overlapping timings of germen formation and cleft defect development [31; 32; 33]. In the study group, when comparing the cleft and no cleft sides, differences were observed in dental pulp volume between the two, with the first group recording significantly smaller sizes. These results are in line with studies described by [PERSON] et al. and [PERSON] et al., who stated that most dental anomalies found were associated with the cleft side [31; 34]. Considering that many CLP patients are subjected to orthodontic treatment, changes in the pulp volume of patients subjected to this type of therapy should be studied in the foreseeable future. During orthodontic treatment, significant forces, albeit controlled, are applied to teeth in order to promote tooth movement. These forces may cause pulpal reactions, pulp hyperemia, releasing inflammatory mediators that in turn increase blood circulation. Under normal circumstances, increased blood circulation decreases inflamma  
Figure 5: Relationship between age and medium pulpal volume. tory mediators, but the pulp is limited by dentin, which impedes the occurrence of this decrease. Subsequently, there is a stimulation of the reparative responses of odontoblasts, leading to the accumulation of tertiary dentin. Studies described in the literature confirm that orthodontic forces reduce the pulp volume, which can vary within a range of 3 to 55.9 mm\({}^{3}\)[35; 36; 37]. In the same way that orthodontic forces promote a volumetric increase in the pulp because of inflammation, periodontal disease, which is highly prevalent in CLP patients, can also generate this effect cascading from gingival inflammation [38; 39]. To date, only a few studies that compare dental pulp volume between CLP and non-CLP patients have been found, which hinders any possible comparisons between the obtained results and the current available literature. The present study is posed with some limitations as it was not possible to perform subgroup analysis in the study sample, namely according to etiology, phenotype, cleft severity and size. Another limitation is the existing discrepancy between the real and the pulp volume calculated from the radiological image.