The impaction of permanent canines is a common developmental anomaly in dentistry, second only to third molars in frequency. It occurs when a canine tooth fails to erupt into its correct position in the dental arch within the expected timeframe. The prevalence of impacted canines varies globally, influenced by genetic, anatomical, and environmental factors [1,2]. Clinically, impacted canines pose challenges due to their significant role in maintaining dental arch aesthetics, occlusal harmony, and facial symmetry. Maxillary canines, which have a complex and prolonged eruption pathway, are more frequently impacted than mandibular canines. Studies have shown that the prevalence of maxillary canine impaction ranges from 1% to 3%, while mandibular canine impaction is relatively rare, reported in less than 0.3% of cases [3,4].

The implications of canine impaction extend beyond aesthetics and function. Impacted canines may lead to root resorption of adjacent teeth, cystic lesions, and increased difficulty in orthodontic or surgical management. The study of impacted canines is crucial because these teeth play a vital role in dental function and aesthetics. Impacted canines can cause misalignment, cyst formation, root resorption of adjacent teeth, and other complications if not properly managed. Consequently, understanding the incidence and prevalence of impacted canines is critical for timely intervention and minimizing complications [5,6]. Radiographic evaluation, particularly panoramic radiographs, is a cornerstone in diagnosing impacted canines. These imaging techniques provide essential insights into the position, orientation, and relationship of impacted teeth with adjacent structures. Retrospective radiographic studies offer a valuable method for assessing patterns and trends in impacted canines across populations [7,8]. Early detection and intervention help prevent orthodontic and surgical challenges, reducing treatment time and costs. Understanding the causes, diagnostic techniques, and treatment options improves patient outcomes. Research also aids in refining surgical and orthodontic approaches, enhancing overall oral health. Moreover, studying genetic and environmental factors influencing impaction can contribute to better preventive strategies, benefiting both patients and dental professionals. [1,4,5]

This study aims to evaluate the incidence and prevalence of impacted permanent canines in a selected population using panoramic radiographs. It also explores gender, age, and localization factors, contributing to a comprehensive understanding of this condition's epidemiological characteristics [9].

Study Design and Population

This retrospective study analyzed panoramic radiographs of patients attending the radiology department of a dental hospital between September 2015 and September 2016. Ethical approval was obtained, and the study adhered to the Helsinki Declaration guidelines for research involving human subjects. All the patients signed a written informed consent.

Inclusion and Exclusion Criteria

Inclusion criteria encompassed patients aged 12 to 50 years with complete dental records and high-quality panoramic radiographs. Exclusion criteria included incomplete records, history of orthodontic treatment, congenital anomalies, and systemic diseases affecting tooth eruption.

Data Collection

A total of 1,498 panoramic radiographs were selected from a pool of 2300 radiographs, as described in Figure-1. Data collected included patient age, gender, type of canine impacted (maxillary or mandibular), side of impaction (unilateral or bilateral), and classification of the impacted tooth. Classification given by Yamamoto et al was used for the maxillary canines and classification given by Mupparapu et.al. was used for mandibular canines. [10,11] All radiographs were analyzed by two independent calibrated observers of equal experience to ensure reliability.

Statistical Analysis

The data were analyzed using SPSS version 26. Descriptive statistics were calculated for categorical variables, while Chi-Square Tests were employed to assess gender and age associations. A p-value < 0.05 was considered statistically significant.

Figure 1: Flowchart for assessment of radiographs for inclusion in the study.

The calibration of the examiners showed a good agreement between the two, with Kappa = 0.673, standard error of kappa = 0.070 and 95% confidence interval from 0.535 to 0.811.  The overall incidence of impacted canines was 4.14% (62 out of 1498 panoramic radiographs) The analysis revealed a higher prevalence of impacted canines in females, with the number being 39 (62.9%) as compared to males 23 (37.1%) as shown in table-1, figure-2. 40 (64.52%) impactions were seen on the left side and 22 (35.48%) were seen on the right side. There were no bilateral impactions seen in the present study. Maxillary impactions were more common in both genders, with 53 (69.74%) being maxillary impactions and 9 (14.52%) being mandibular impactions. A detailed analysis reveals that in males, 20 (32.26%) were maxillary impactions and 3 (4.84%) were mandibular

impactions. In females, 33 (53.23%) were maxillary impactions and 6 (9.68%) were mandibular impactions. As far as the age distribution is concerned, both the genders showed a similar trend, with the age group of 20 years to 29 years showing the maximum number of canine impactions i.e. 29 (46.77%), followed by the age groups of 10 to 19 years showing 14 (22.58%) impactions, age groups of 30 to 39 years showing 10 (16.13%) impactions, and age groups of 40 to 59 years showing 7 (11.29%) impactions. The least number of impactions i.e. 2 (3.23%) were seen in the age group of 50 to 59 years. The number of maxillary and mandibular impactions appears to be highly co-related in both genders as shown in Figures 3 and 4. The gender distribution did not show any significant difference in Chi-Square Test (p value =.80).

Table 1: Gender, age and site distribution of impacted Canines

The chi-square statistic is 1.77,  p-value is .80, not significant at p < .05

Figure 2: Gender, age and site distribution of impacted Canines

Figure 3: Co-relation between both genders for maxillary impactions.

Figure 4: Co-relation between both genders for mandibular impactions.

Table 2: Maxillary canine impaction distribution (According to classification system given by Yamamoto et.al., 2003 [10])

The maxillary canines showed a similar trend of impactions in both the genders, when classified according to the classification system given by Yamamoto et.al., 2003 [10], with Type I accounting for the maximum number of impactions i.e. 26 (41.94%), out of which 9 (14.52%) were seen in males and 17 (27.42%) were seen in females. This was followed by 16 (25.81%) Type II impactions, out of which 5 (8.06%) were males and 11 (17.74%) were females. Type III was the next in frequency with 7 teeth (11.29%), out of which 4 (6.45%) were males and 3 (4.84%) were females. This was followed by one male (1.61%) showing Type V impaction and one female (1.61%) showing Type VI impaction. The least was Type IV in both genders (0%). The above data is depicted in table-2 and figure-5. The gender association was not statistically significant for maxillary canines as determined by Chi Square Test (p value = .62). 

Mandibular canines, when classified according to the classification system given by Mupparapu et.al., 2002 [11], showed the maximum number of impacted canines as Type II, i.e. 5 (8.06%), out of which 2 (3.23%) were males and 3 (4.84%) were females. This was followed Type I impactions which were a total of 3 (4.84%), out of which 1 was male (1.61%) and 2 were females (3.23%). Only one female (1.61%) showed Type III impacted canine. The least were Type IV and Type V, both as 0%. The above data is depicted in table-3 and figure-6. The gender association was not statistically significant for mandibular canines as determined by Fisher Exact Test (p value = 1.0).

Figure 5: Maxillary canine impaction (According to classification system given by Yamamoto et.al., 2003 [10])

Table 3: Mandibular canine impaction distribution (According to classification system given by Mupparapu et.al, 2002, [11])

Fisher’s Exact Test result: Odds Ratio = 0.75, p-value = 1.0, not significant.

Figure 6: Mandibular canine impaction distribution (According to classification system given by Mupparapu et.al, 2002, [11])

Impacted teeth are commonly seen in the human population, with the mandibular third molar being the most commonly impacted tooth in numerous studies [12]. Impacted canine teeth occur when the upper or lower canine teeth fail to erupt properly into their correct position. This is most common in the upper jaw, affecting about 1-3% of the population. Causes include genetic factors, overcrowding, prolonged retention of baby teeth, or abnormal tooth eruption paths. Impacted canines can lead to misalignment, cyst formation, damage to adjacent teeth, and gum infections. Early diagnosis through dental X-rays and orthodontic evaluation can help manage the condition. Treatment options include orthodontic braces, surgical exposure, or extraction if necessary. Early intervention, especially in children, improves the chances of successful correction. The impaction of permanent canines remains a topic of clinical interest due to its multifactorial etiology and diverse presentations. This study aimed to elucidate the prevalence and characteristics of impacted canines in a regional population using retrospective radiographic data. [13]

The incidence of maxillary canines is estimated to be around 1-3% of the population. It is more common in females than males, with a female-to-male ratio of approximately 2:1. The same trend was observed in our study, although the gender distribution was not statistically significant in any of

the analysis. About 85% of impacted canines occur on the palatal side, while 15% occur on the buccal side. Bilateral impaction (affecting both upper canines) is less frequent than unilateral impaction, which was also shown in our study as we did not encounter any bilateral impacted canines. [14] The condition is often linked to genetics, dental crowding, or delayed exfoliation of baby teeth. Early diagnosis through X-rays and orthodontic evaluation can help prevent complications and improve treatment success.

The incidence of impacted mandibular canines is much lower than that of impacted maxillary canines, occurring in approximately 0.2–1.3% of the population. Unlike maxillary canines, mandibular canine impactions are more commonly found in the vertical position rather than being displaced palatally or buccally. [15] Impacted lower canines can be caused by genetic factors, lack of space, prolonged retention of primary teeth, or abnormal eruption paths. They may lead to misalignment, root resorption of adjacent teeth, and cyst formation. Treatment options include orthodontic traction, surgical exposure, or extraction if alignment is not feasible. Early detection improves treatment outcomes. [15]

The observed prevalence of 4.2% aligns with global estimates ranging from 1% to 5%. A study by Pooja Umaiyal et. al. [13] The higher prevalence of maxillary canine impaction (85%) corroborates findings from studies by Walker et al. [16] and Shah et al. [17], emphasizing the anatomical and eruption path complexities of maxillary canines. Our study found a female predilection for impacted canines, consistent with previous research [18,19]. Hormonal influences and differences in craniofacial morphology between genders may contribute to this trend. Unilateral impaction predominated in this study. These findings align with studies by Zawawi et al. [20] and Alqerban et al. [21], who reported similar patterns. Early detection of impacted canines is crucial for minimizing complications such as resorption of adjacent teeth, cyst formation, and prolonged treatment times. Panoramic radiographs remain a valuable diagnostic tool for assessing impaction severity and planning interventions.

Maxillary canines were predominantly impacted, accounting for 85% of the cases, whereas mandibular canines represented only 15%. This is in accordance with study by Al-Zoubi et. al. [17] This stark disparity is consistent with the complex eruption pathway and anatomical characteristics of maxillary canines, which predispose them to impaction. These findings emphasize the importance of vigilant radiographic monitoring of maxillary canines during routine dental evaluations. Unilateral impaction was observed in 100% of cases. The higher occurrence of unilateral impaction suggests that localized factors, such as arch space deficiency or path of eruption, may play a more significant role than systemic factors. This distribution has clinical implications for individualized treatment planning, as unilateral impaction often requires less invasive interventions compared to bilateral cases.

In maxillary canines, according to classification system given by Yamamoto et.al., 2003 [10], maximum number of impactions (67.74%) were classified as Type I and Type II. This is in accordance with study by Alassiry et al. [22]. In mandibular canines, according to classification system given by Mupparapu et.al, 2002, [11], almost all were included in Type I and Type II. This is in contrast to study by Agastra. [23] Such differences are heavily affected by the sample size of the study, so conflicting and similar results can be seen occasionally. One crucial factor needed to support the proper eruption and growth of teeth is a suitable jaw size. Tooth impactions are more likely to occur when there are differences in jaw size that correspond to evolutionary variations and a lack of sagittal expansion.[25] In a similar context, teeth impaction is known to result from a lack of arch length. For example, a dysplastic premaxilla can change the maxillary canine's eruption route after the lateral incisor's eruption, increasing the likelihood of impaction.[26] Maxillary canine impaction has been found to occur much more frequently in cleft and palate patients with maxillary skeletal growth deficits than in controls.[27]

This study's strengths include its use of standardized radiographic analysis with calibrated observers of similar experience. It allowed for the analysis of a large dataset over time, providing valuable insights into prevalence, patterns, and associated factors. It was cost-effective and time-efficient since data was already available. Additionally, it minimized ethical concerns related to patient exposure to radiation. However, the limitations of the present include its retrospective design and the inability to assess contributing factors such as genetic predisposition, potential biases due to inconsistent imaging techniques, incomplete records, and variability in diagnostic criteria. It lacked control over data collection, making it difficult to standardize measurements. Furthermore, retrospective studies cannot establish causality, limiting their ability to determine the exact reasons for canine impaction. Prospective studies incorporating genetic and environmental assessments are recommended to further elucidate the etiological factors of impacted canines. Advances in imaging modalities, such as cone-beam computed tomography (CBCT), may provide more precise evaluations.

This retrospective radiographic study highlights the incidence and prevalence of impacted permanent canines, offering valuable insights for clinical and preventive dentistry. These findings underline the multifactorial etiology of canine impaction, including genetic predisposition, anatomical constraints, and localized factors. The results emphasize the critical role of panoramic radiographs in the early detection and management of impacted canines. Timely diagnosis can prevent complications such as root resorption, cyst formation, and alignment issues, improving overall treatment outcomes.

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