IMPACTED MAXILLARY CANINES AND WHAT AFFECTS THEIR TREATMENT TIME

Dina Vasovic, Tina Pajevic, Ljiljana Vucic, Branislav Glišic, Jovana Juloski

What did the authors aim to do in this study?

The primary objective of this study was to determine the factors associated with the treatment duration in impacted maxillary canines (IMCs) using orthopantomography & cone beam computed tomography.

How did the authors evaluate?

The study was carried out by classifying maxillary canines as impacted on OPG if more than two-thirds of the tooth root was developed while the tooth remained fully or partially covered by bone. Patients identified with IMCs on OPG underwent CBCT of the maxilla. The inclusion criteria for the study had patients with at least one diagnosed unerupted maxillary canine who underwent treatment involving forced eruption or extraction and possessed complete diagnostic records (OPG and CBCT) along with treatment details, such as the dates of surgical exposure and ligation of a full-size stainless steel archwire. The exclusion criteria included patients with clefts or syndromes as well as those who missed appointments. All necessary data were extracted from the diagnostic records. The study included 64 patients with 83 impacted canines.

Fig 1. Reference lines & parameters measured on OPG Reference lines: occlusal plane (OccP): traced from the mesial cusp of the maxillary first molars to the incisal margins of central incisors; sagittal medial line (SML): line connecting proximal contact point of the maxillary central incisors and anterior nasal spine; axis of impacted canine (C): connecting canine crown tip (T) and apex (A); adjacent lateral incisor (LI) and first premolar (PM).

Measurements for 30 patients were done twice, 2 weeks apart, to establish intra-class correlation coefficients. Three-dimensional evaluation was done on sagittal, coronal, and axial views of the CBCT scans that were taken. All canines were exposed using a closed surgical technique. Orthodontic traction force was initiated approximately 7–10 days after surgical sutures were removed and was reinforced monthly thereafter. Duration until the initial appearance of the canine tip in the mouth was recorded as the period between surgical exposure and canine tip visibility in months. The duration of the forced eruption phase was defined as the interval between surgical exposure and achieving ideal alignment of IMCs, marked by ligating all teeth onto a stainless steel 0.016 x 0.022-inch archwire. Treatment success was defined as achieving fully functional eruption of the canine without requiring additional intervention. If extraction of canines was necessary, it was noted whether the teeth were extracted at the beginning of treatment or after surgical exposure and attempted orthodontic traction. Treatment failure was determined by the extraction of the canine following unsuccessful orthodontic traction efforts.

Fig 2. Parameters measured on CBCT (1) panoramic position of an impacted tooth: (a) mesial, (b) vertical, distal, and (c) horizontal; and (2) distance between lateral incisor and first premolar measured in mm

What did the authors find?

They found that the average treatment duration of canines localized around lateral incisors had shorter treatment times than those localized around central incisors. The canines that were inclined >30° to the sagittal medial line (SML) had significantly longer treatment time until initial appearance in the mouth when compared with those inclined less. Linear regression analyses demonstrated that these factors were predictors for both treatment duration until emergence and ideal alignment of the canine.

What did the authors conclude?

• Treatment duration for IMCs is notably lengthy, particularly for palatally and mesially positioned canines and those with greater inclinations.

• Palatally located canines typically require twice as much time to emerge than those positioned buccally.

• Canines located nearer the central incisor area take twice as much time to emerge than those located in the lateral incisor area.

What do we think about it?

Among all the impaction scenarios present, Impacted maxillary canines are the second most commonly found impactions followed by the third molars. The localization of the impacted canines and their accuracy is very important and mostly relies on radiography. The most commonly used tool for this is the orthopantomography. Although it offers an accurate representation, it has the drawback that only a 2- dimensional view can be seen using this diagnostic tool. To overcome this, the cone beam computed tomography was introduced. CBCT enables the precise localization of the impacted teeth and facilitates decision-making regarding further treatment. Treatment modalities for impacted canines typically include surgical exposure followed by orthodontic extrusion or extraction. This study was carried out very comprehensively, including all the aspects and all the analyses were very meticulously done to prevent any errors from occuring. It is very essential for us to approximately estimate the treatment duration of an impacted tooth so that we can plan the management & also keep the patient informed accordingly.

Dina Vasović, Tina Pajević, Ljiljana Vučić, Branislav Glišić, Jovana Juloski; Factors influencing treatment duration of impacted maxillary canines. Angle Orthod 2025