# Root Dilaceration and Dentigerous Cyst--A Cause-Effect Relationship?--\"Case-Series Study\"
## 2 Materials and Methods  
This retrospective case series study was performed on five patients (two females and three males) from a private practice aged between 8 and 10 years old. In accordance with the Helsinki Declaration of 1975, as revised in 2008, informed consent was asked of all patients for their participation in the study. The patients had sought orthodontic treatment, either for different reasons and the cyst, and subsequently, the root DL were detected at the routine X-ray exam or for the absence of a permanent tooth that must have erupted at that age. The inclusion criteria were the presence of root DL of at least one tooth and a DC of developmental origin, including the dilacerated tooth or another tooth nearby. The exclusion criteria were as follows: syndromic patients, other types of cysts, history of trauma, and previous orthodontic treatment. All types of dilacerations were included, as described in the introduction. Both DLs and DCs were initially detected and diagnosed by an X-ray exam, especially panoramic X-ray, while differential diagnosis and more precise details were obtained with the aid of CBCT using the VGI Evo scanner (NewTom, Verona, Italy) with a field of view (FOV) of 15 \(\times\) 12 cm. The treatment objective for DC in all cases was to preserve the cyst-associated tooth and to marsupialise the cyst with or without orthodontic traction of the tooth. The use of orthodontic traction depends on the size of the cyst, the position of the tooth, tooth depth, and stage of root development [57]. The study aimed to assess the cause-effect relationship between DCs and root DLs. **Case 1**  
A girl aged ten was brought by her parents for orthodontic treatment due to aesthetic reasons. She was in average mixed dentition with all first premolars intraorally, except for the upper right one, where the deciduous molars presented caries and massive coronal destructions, which might be the causes of the delayed eruption of the first premolar. At a routine X-ray exam, it was noted that the right upper canine with a DC was in a very high position in the bone, mesially inclined, in transposition with the upper first premolar and in closed contact with its apical half of the root, which was already dilacetated, with a mesioangulation (Figure 1a). This position could be a risk factor for canine impaction. Because of the lack of space and crowding, after the extraction of right deciduous molars (to facilitate the eruption of the premolars), the first step of the treatment plan was maxillary expansion, which could have also been a preventive method of canine impaction. After maxillary expansion, the first premolar partially erupted, but the second one was impacted due to the lack of space and both distally inclined and completely formed roots. The roots of the premolars had different types of DLs, from a slight flexion of the second premolar's root to a true dilacetated root of the first premolar. The canine remained in the same position while the DC was still growing (Figure 1b). To obtain more space for upper premolars and canines, the patient wore a low pull headgear to distalize the upper first molar and then fixed appliances to fulfil the objective of the orthodontic treatment. Because the canine did not change its position (Figure 1c), marsupialization of the cyst was tried, and consequently, the canine started to erupt between the roots of the first premolar. At this moment, it has been decided to incline the roots of the first premolar distally to prevent root resorption by the canine. Regarding the cause-effect association between DC and root DL, in this case, DC could be the cause of root DL (taking into consideration the initial high and mesioinclined position of the canine, in transposition with the first premolar, along with its DC that had  
Figure 1: **(a)** Initial panoramic X-ray showing the upper right canine in a very high position and transposition with the first premolar. **(b,c)** Different types of root DL affecting right premolars.