Avaliação do processo coronoide da mandíbula de indivíduos com neurofibromatose tipo 1 por meio de tomografia computadorizada de feixe cônico

Abstract

Neurofibromatosis type 1 (NF1) is an autosomal dominant disease caused by mutations in the NF1 gene, which can cause various bone changes, including in the craniofacial skeleton, one of which is hyperplasia of the coronoid process (HCP). However, no study had been carried out to evaluate it in patients with NF1, in comparison with a control group. Therefore, the present study aimed to evaluate the morphology, dimension and volume of the coronoid process (CP) of individuals with NF1, using cone beam computed tomography (CBCT). The experimental group consisted of CBCT images from 54 individuals with NF1, while the control group consisted of exams from 54 individuals without the pathology, matched by gender and age. CP was classified into 4 morphological patterns, namely triangular, rounded, hooked and flattened. Its height was measured, as well as the height of the mandible head to calculate the ratio between these structures, originating the Coronoid Process-Mandible Head Index (CCMI). Furthermore, the CP volume was obtained through semiautomatic segmentation with manual refinement performed in the ITK-SNAP software (Cognitica, Philadelphia, PA, USA). The images were evaluated by dental surgeons and radiologists and were previously calibrated. Regarding morphological patterns, the triangular type was the most predominant in the experimental group (right and left sides =74.1%) as well as in the control group (right and left sides =68.5%). The assessment of CP height did not demonstrate statistical significance in the comparison between groups (p right =0.207 and p left =0.364). However, when the comparison was made between the genders, a significant difference was found for the experimental group (right = 0.005 and left = 0.049) with males presenting higher heights (right side = 14.39 mm and left side = 13.64 mm) than female (right side = 12.19 mm and left side = 12.16 mm). In relation to the CCMI, an index that identifies the presence of HCP, when equal to or greater than 1, a statistically significant difference was observed (p right =0.001 and p left = 0.006) in the comparison between the groups, with a higher proportion of values equal to or greater than 1 for the experimental group (right side = 40.7% and left side = 35.2%) in relation to the control group (11.1% for both sides), indicating a higher frequency of HCP for the experimental group. The volumetric evaluation identified higher values for the experimental group (right side = 271.1 mm 3 and left side = 268.9 mm 3 ) compared to the control group (right side = 247.5 mm 3 and left side = 245.7 mm 3 ), but without statistical significance (p right =0.202 and p left = 0.169). In conclusion, our results showed that HCP was more prevalent in individuals with NF1. It was also observed that CP heights for males were higher within the experimental group.