Incisor root resorption associated with palatally displaced maxillary canines: Analysis and prediction using discriminant function analysis

Abstract

Incisor root resorption associated with palatally displaced canine (PDC-IRR) is an important phenomenon that might alter the orthodontic treatment plan. The aims of this study were to investigate the prevalence and characteristics of PDC-IRRs, to compare PDC-IRR and PDC-No-IRR groups, to identify predictors for PDC-IRR, and to produce a valid PDC-IRR prediction model using discriminant function analysis. Methods: Cone-beam computed tomography images for 107 palatally displaced canines (PDCs) and 51 fully erupted nondisplaced canines (NDC) were analyzed for the presence of incisor root resorption (IRR). The PDCs were divided into 2 groups: PDC-IRR (52 canines) and PDC-No-IRR (55 canines). The 3 groups were compared, and the following variables were measured: canine follicle size, contact with adjacent incisors, associated dental abnormalities, sector analysis, canine vertical relation to adjacent root, lateral incisor angulation and inclination, canine angulation and distance to reference planes (dental midline, midpalatal suture, occlusal plane, pterygoid vertical plane, and lateral incisor), and space available for canine in the dental arch. Discriminant functional analysis was used to produce a discriminant function equation to predict PDC-IRR. Results: Root resorption affected 74% of lateral incisors adjacent to PDCs and 25.5% of lateral incisors adjacent to NDCs. IRR was located lingually in 41% of PDCs and in the mid and apical thirds in 89%. In the PDC-IRR group, 94.2% of canines were in contact with adjacent roots compared with 23.6% in the PDC-No-IRR group (P \0.001). Canine follicle size was .2 mm in 42% of PDC subjects. Overall mean value of follicle width in PDC canines was 1.79 6 1.06 mm. Peg-shaped lateral incisors were recorded in 19% of PDC subjects compared with 4% in NDCs (P 5 0.012). The stepwise analysis using cone-beam computed tomography records produced a discriminant function based on 3 variables. The analysis correctly predicted the outcome in 83% of subjects. The variables contributing to the prediction equation were canine contact with adjacent incisors, size of canine dental follicle, and the presence of peg-shaped lateral incisor. Conclusions: Canines in contact with adjacent incisor roots was the only risk factor detected for PDC-IRR. Very good predictive discrimination (83%) emerged for PDC-IRR subjects. Predictors of PDC-IRR were canine contact with adjacent incisor, size of canine dental follicle, and presence of peg-shaped lateral incisor.

Incidence of lateral incisor root resorption associated with impacted maxillary canines

“…3,15,26 The consensus in the literature confirms that canine angulation does not appear to be related to the prevalence nor the severity of incisor root resorption. 9,[17][18][19]29 The number of females in the present study presenting with impacted canines was more than double that of males but there was no apparent association between gender and the incidence or severity of lateral incisor resorption. While there is some agreement 9,12,17 earlier studies found that the risk of severe incisor resorption was disproportionately greater in females.…”

“…12 Further studies have identified an incidence ranging from 17% to 67%. 3,[13][14][15][16][17][18][19] Significantly, a high proportion of cases revealed severe resorption extending to the pulp of the lateral incisor 12,20,21 and so the early diagnosis of the severity and extent of resorption is crucial. A CT examination of ectopically erupting maxillary canines led to a change in 53% of the original treatment plans of patients diagnosed with lateral incisor root resorption.…”

Cone beam computed tomography (CBCT) assessment of incisor root resorption (IRR) associated with impacted maxillary canines (IMC). Literature review

“…CBCT images for 107 palatally displaced canines (PDCs) and 51 fully erupted nondisplaced canines (NDC) were analyzed for the presence of incisor root resorption (IRR) (23). Root resorption affected 74% of lateral incisors adjacent to PDCs and 25.5% of lateral incisors adjacent to NDCs.…”

Predictive factors associated with adjacent teeth root resorption of palatally impacted canines in Arabian population: a cone-beam computed tomography analysis

“…The majority of maxillary canine impactions were close to the adjacent teeth and might be a source of root resorption [ 6 – 9 ]. The overall incidence of palatally impacted maxillary canines is 56.99 and 56.87% are associated with adjacent teeth root resorption [ 7 , 10 ]. The presence and extent of root resorption of the adjacent teeth may complicate the orthodontic treatment plane.…”