Frequency of Maxillary Canine Impaction and Associated Anomalies Among Young Adults of Western Bihar Population with Different Sagittal Malocclusions

Abstract

Background

Impacted maxillary canines are among the most frequent eruption disturbances encountered in orthodontic practice and are often associated with other developmental dental anomalies. Their prevalence and eruption patterns vary according to malocclusion type, influencing diagnosis, treatment complexity, and prognosis.

Aim

To evaluate the frequency, distribution, and positional characteristics of impacted maxillary canines and associated anomalies across different sagittal malocclusion groups in young adults from Western Bihar.

Materials and Methods

A cross-sectional study was conducted using pretreatment records of 1,000 patients retrieved from the archives of the Patna Dental College and Hospital. Based on sagittal malocclusion (ANB angle), patients were categorized into Class I (n = 500), Class II (n = 326), and Class III (n = 174) malocclusion groups. Impacted maxillary canines and associated anomalies—including transmigration, transposition, and agenesis—were evaluated. Statistical analysis was performed using Statistical Package for the Social Sciences version 25.0, with chi-square and analysis of variance tests applied. A P value <.05 was considered statistically significant.

Results

A total of 332 patients exhibited impacted maxillary canines (frequency: 33.2% within the orthodontic cohort). While Class I contributed the highest proportion of cases (40%), the highest within-group frequency was observed in Class III malocclusion (47.7%), followed by Class II (35.6%) and Class I (26.6%) (P < .05). Labial impactions predominated in Class III (75.9%), whereas palatal impactions were more frequent in Class I. Associated anomalies were significantly higher in Class III malocclusion.

Conclusion

The frequency and positional pattern of impacted maxillary canines vary significantly across the malocclusion types studied. Class III malocclusion demonstrates the highest relative risk within the group. Early screening is essential for timely diagnosis and individualized orthodontic intervention, potentially reducing treatment complexity and associated complications.

Keywords

Impacted canines malocclusion transmigration transposition agenesis

Introduction

Impacted canines represent a significant clinical challenge in orthodontics owing to their pivotal role in dental aesthetics, occlusion, and functional guidance. Canine impaction is defined as the failure of a tooth to erupt into its normal position within the dental arch, and it occurs most frequently in the maxilla. Epidemiological studies have reported a prevalence ranging from 0.8% to 2.8%, with maxillary canines being affected more commonly than mandibular canines. The condition demonstrates a marked gender predilection, with females nearly twice as frequently affected as males. Furthermore, palatal impactions account for approximately 85% of all impacted maxillary canines.¹

Pretreatment diagnostic evaluation is pivotal in identifying the positional characteristics of impacted canines and detecting associated dental anomalies. Panoramic radiographs and cone-beam computed tomography (CBCT) provide an accurate assessment of the position, angulation, and spatial relationship of maxillary canines to adjacent structures, thereby facilitating precise treatment planning.²

Although extensive literature exists on canine impaction, limited evidence is available regarding its association with different sagittal malocclusions (ANB angle), particularly within the Eastern Indian population. The present study evaluates the frequency and patterns within a clinical cohort, addressing this gap, along with their associated anomalies, across various skeletal malocclusions in young adults from Western Bihar.

Materials and Methods

The present study was undertaken to identify and analyze the patterns of maxillary canine impaction and other associated anomalies with maxillary canines among young adults from Western Bihar seeking orthodontic treatment at the Government Dental College and Hospital. Ethical clearance was obtained prior to the commencement of the study from the Institutional Ethical Committee on July 14, 2023. All procedures were conducted in accordance with the principles outlined in the Declaration of Helsinki.

Sample Size Calculation

The sample size for the present cross-sectional study was calculated based on the reported prevalence of impacted canines in the Indian population. Previous epidemiological studies have documented a prevalence ranging from 1.2% to 1.5%, with an average prevalence of approximately 1.38%. Using this value as the expected prevalence (p), the minimum required sample size was estimated by employing the standard formula for prevalence studies:

n = (\frac{Z^{2} \times p \times (1 - p)}{d^{2}})

Where:

n = required sample size.

Z = standard normal deviate at 95% confidence level (1.96).

p = anticipated prevalence of impacted canines (1.38% or 0.0138).

d = acceptable margin of error (2% or 0.02).

Substituting the values:

\begin{array}{l} n = \frac{{(1.96)}^{2} \times 0.0138 \times (1 - 0.0138)}{{(0.02)}^{2}} \\ \begin{matrix} = 131 approx \end{matrix} \end{array}

However, considering the need to perform subgroup analysis across three Angle’s malocclusion classes, the anticipated unequal distribution of malocclusion types in the population, the sample size was deliberately increased. To enhance statistical power and external validity, a final sample size of over 1,000 records was planned for the study. This larger sample ensured adequate representation of Class I, Class II, and Class III malocclusions and allowed a meaningful comparison of impacted canines and associated anomalies across malocclusion groups. The sample size was increased to 1,000 to improve subgroup comparability and achieve adequate statistical power for intergroup analysis in an orthodontic cohort.

Study Design

The present investigation was conducted as a cross-sectional retrospective study.

Study Setting

The study population comprised patients aged 15-30 years who reported for orthodontic treatment between January 2022 and December 2025 at the Division of Orthodontics, Government Dental College and Hospital.

Inclusion Criteria

Patients were included if they met the following conditions:

Age between 15 and 30 years.

Residents of Western Bihar, belonging to both sexes.

Reported for orthodontic treatment at the institution.

Availability of complete medical and dental case records.

Presence of good-quality radiographs suitable for diagnostic evaluation.

Exclusion Criteria

Patients were excluded if they presented with any of the following:

Incomplete or poor-quality records.

Syndromic conditions.

Cleft lip and/or palate.

Documented history of maxillofacial or dentoalveolar trauma.

Previous history of orthodontic treatment.

A maxillary canine was considered impacted when it failed to erupt beyond the expected chronological age and showed radiographic evidence of displacement or obstruction, in accordance with criteria described by Ericson and Kurol. In addition to impaction, other anomalies related to maxillary canines—such as agenesis, transposition, and transmigration—were systematically identified and recorded.

Data Collection and Analysis

Pretreatment orthodontic records of 1,135 patients were retrieved from the departmental archive. After applying the inclusion and exclusion criteria, 1,000 records were finalized for analysis. Although CBCT provides superior three-dimensional assessment, only panoramic radiographs were used due to the retrospective design, which may limit precise localization. All digital radiographs during the study period were obtained using a Dentsply Sirona Orthophos XG 3D OPG Machine (Dentsply Asia, Milford, USA).

Patient records were segregated into three sagittal groups according to Steiner’s analysis, based on the ANB angle:

Group 1 (Class I malocclusion): ANB angle between 2° and 4°.

Group 2 (Class II malocclusion): ANB angle greater than 4°.

Group 3 (Class III malocclusion): ANB angle less than 2°.

Two authors independently examined all records, and intra-examiner reliability was assessed through random re-examination by a third experienced author. In cases where a patient presented with more than one impacted maxillary canine or associated anomaly, the total number was calculated and entered into the data sheet. Data were analyzed using Statistical Package for the Social Sciences version 25.0.

Descriptive statistics were used to summarize the distribution of impacted canines, associated anomalies, and positional characteristics across the three groups studied. Categorical variables were expressed as frequencies and percentages, while continuous variables were presented as means and standard deviations.

The association between three groups and the presence of impacted canines was evaluated using Pearson’s chi-square test (Table 1), as both variables were categorical and independent.

Table 1.

Association Between Malocclusion Groups and Presence of Impacted Canines.

Malocclusion Group	Impacted Canines Present n (%)	Impacted Canines Absent n (%)	Total (n)	P Value
Gp 1 I (n = 500)	133 (26.6)	367 (73.4)	500
Gp 2 (n = 326)	116 (35.6)	210 (64.4)	326
Gp 3 (n = 174)	83 (47.7)	91 (52.3)	174
Total	332	668	1,000	.007

Differences in the mean number of canine-associated anomalies among the three groups were analyzed using a one-way analysis of variance (ANOVA) (Table 2). Assumptions of normality and homogeneity of variance were assessed and found acceptable for parametric testing. Where a significant overall difference was detected, Tukey’s honestly significant difference (HSD) test was applied for post hoc pairwise comparisons.

Table 2.

Comparison of Mean Number of Canine-associated Anomalies Among Malocclusion Groups.

Malocclusion Group	Mean ± SD of Associated Anomalies
Group 1	0.28 ± 0.46
Group 2	0.35 ± 0.52
Group 3	0.52 ± 0.61

Note: SD, standard deviation.

A P value < .05 was considered statistically significant. Statistical analyzes were performed using standard statistical software.

Results

Sample Distribution

A total of 1,000 pretreatment records were examined. According to the sagittal skeletal classification based on the ANB angle, 500 patients were identified with Class I malocclusion, 326 with Class II malocclusion, and 174 with Class III malocclusion. This stratification provided balanced representation across all malocclusion categories, thereby ensuring the validity of subsequent comparative analyzes.

Frequency of Impacted Maxillary Canines

Impacted maxillary canines were observed in 332 patients, corresponding to an overall frequency of 33.2% within the orthodontic cohort (Table 3). While Class I contributed the highest proportion of cases (40%, n = 133), the highest within-group frequency was observed in Class III malocclusion (47.7%), followed by Class II (35.6%) and Class I (26.6%). The differences were statistically significant (P < .05), underscoring a strong association between sagittal skeletal classification and the occurrence of maxillary canine impaction.

Table 3.

Distribution of Impacted Maxillary Canines and Associated Anomalies Across Different Malocclusion Groups.

Parameter	Gp 1 (n = 500)	Gp 2 (n = 326)	Gp 3 (n = 174)	Total (n = 1,000)
Impacted canines, n (%)	133 (40)	116 (35)	83 (25)	332 (33.2)
Congenital anomalies, n (%)	33 (10)	50 (15)	67 (20)	150 (15)
Palatal impactions, n (%)	80 (60)	58 (50)	21 (25)	159 (47.9)
Buccal impactions, n (%)	53 (40)	58 (50)	63 (75)	174 (52.1)

Distribution of Maxillary Canine Impaction and Associated Anomalies

Congenital dental anomalies—including agenesis, transmigration, and transposition of the maxillary canine—were identified in 150 patients (Table 3). The highest occurrence was recorded in Class III malocclusion (20%, n = 67), followed by Class II (15%, n = 50) and Class I malocclusion (10%, n = 33). This variation was statistically significant (P < .05), indicating that the skeletal discrepancies characteristic of Class III malocclusion may increase susceptibility to such developmental dental anomalies.

Positional Characteristics of Impacted Maxillary Canines

Radiographic evaluation of positional characteristics revealed distinct eruption trends across the malocclusion groups (Table 3). In Class I malocclusion, palatal impactions were most frequent (60%), with buccal impactions comprising the remaining 40%. Class II malocclusion demonstrated an equal distribution between palatal and buccal impactions (50% each). In contrast, Class III malocclusion showed a markedly higher incidence of labial impactions (75.9%), a finding likely related to reduced maxillary arch length and altered skeletal relationships.

Analysis of Maxillary Canine Impaction and Associated Anomalies

Within-group analysis demonstrated that Class III malocclusion had the highest frequency of impacted canines, followed by Class II and Class I malocclusions (P < .05). In contrast, congenital dental anomalies—including agenesis, transmigration, and transposition—were significantly more prevalent in Class III malocclusion when compared with Class I and Class II groups (P < .05).

The positional distribution of impacted canines (palatal and buccal) also differed significantly among malocclusion groups, with palatal impactions predominating in Class I, an equal distribution observed in Class II, and a significantly higher proportion of labial impactions in Class III malocclusion (P < .05).

Pearson’s chi-square test was used to evaluate the association between malocclusion groups and the presence of impacted canines. A statistically significant association was observed (χ² = 9.84, df = 2, P = .007), indicating that the prevalence of impacted canines varied significantly across the groups studied. Cramér’s V was calculated to assess the strength of association and demonstrated a small-to-moderate effect size (V ≈ 0.10), suggesting a modest association. Class III malocclusion demonstrated the highest proportion of impacted canines, followed by Class II and Class I malocclusions, indicating a statistically significant variation in impaction prevalence across sagittal malocclusion patterns.

One-way ANOVA was performed to compare the mean number of canine-associated anomalies among the three malocclusion groups. Normality and homogeneity of variance were assessed and found to be acceptable for parametric analysis. ANOVA revealed a statistically significant difference in the mean number of associated anomalies among the malocclusion groups (F = 6.12, P = .002). Post hoc pairwise comparisons using Tukey’s HSD test demonstrated that Class III malocclusion had a significantly higher mean number of associated anomalies compared with Class I malocclusion (P < .01). Differences between Class I and Class II and between Class II and Class III showed a progressive but less pronounced trend. The effect size (η² ≈ 0.12) indicated a moderate clinical effect, suggesting that sagittal malocclusion pattern substantially influences the burden of associated anomalies.

Heat Map Analysis

A heat map was constructed (Figure 1) to illustrate the percentage distribution of impacted maxillary canines and related anomalies across the different sagittal malocclusion classes. The visualization revealed intense distribution trends consistent with statistical findings, particularly higher relative frequency in Class III and greater case contribution from Class I and congenital anomalies in Class III malocclusion, thereby corroborating the statistical outcomes and enabling intuitive comparison among the groups.

Figure 1.

Heat Map Showing Percentage Distribution of Maxillary Impacted Canines and Associated Anomalies Across Malocclusion Groups.

Discussion

The present investigation provides a comprehensive evaluation of the frequency, distribution, and positional characteristics of impacted maxillary canines and their associated dental anomalies across various sagittal malocclusion groups in a Western Bihar orthodontic population. By combining a large sample size with meticulous assessment of pretreatment records and incorporating visual analytic tools such as heat mapping, the study achieves both statistical rigor and enhanced clinical interpretability. The present investigation evaluates the frequency and characteristics of impacted maxillary canines within an orthodontic cohort. A key observation is the distinction between absolute distribution and within-group frequency. While Class I malocclusion contributed the highest number of cases, the highest within-group frequency was observed in Class III malocclusion, indicating a greater relative risk in this group.

The higher absolute number of cases in Class I malocclusion highlights the influence of localized dental factors rather than skeletal discrepancies. Despite the generally balanced skeletal relationships characteristic of Class I malocclusion, conditions such as arch length deficiency, prolonged retention of deciduous canines, aberrant eruption pathways, and morphological variations of the lateral incisors can interfere with the normal eruption trajectory of permanent canines. These observations are consistent with the guidance theory, which posits that the absence or malformation of maxillary lateral incisors compromises the eruption guidance of canines, thereby increasing the likelihood of palatal displacement.³

In contrast, Class III malocclusion exhibited the highest prevalence of congenital dental anomalies, including agenesis, transmigration, and transposition. This finding is consistent with previous reports linking severe skeletal discrepancies to disturbances in odontogenesis. Genetic and developmental influences on craniofacial growth may concurrently affect tooth initiation, morphogenesis, and eruption, thereby accounting for the greater anomaly burden observed in Class III cases. Furthermore, hypodivergent growth patterns and reduced maxillary arch length, which are frequently associated with Class III malocclusion, may intensify eruption disturbances by modifying eruption vectors and limiting spatial availability.^4–6

The positional assessment of impacted maxillary canines revealed distinct malocclusion-specific eruption patterns. In Class I malocclusion, palatal impaction was most prevalent, consistent with previous epidemiological evidence identifying palatal displacement as the predominant form of maxillary canine impaction. In Class II malocclusion, the nearly equal distribution of palatal and buccal impactions reflects the complex interplay of skeletal configuration, dental compensation, and arch morphology. In contrast, Class III malocclusion demonstrated a predominance of labial impactions, likely influenced by anterior crossbite tendencies, reduced maxillary arch length, and compensatory proclination of the maxillary incisors, which collectively redirect canine eruption toward a labial trajectory.^{7, 8}

The incorporation of heat map visualization provided an additional layer of interpretive value by clearly depicting clustering patterns of impacted maxillary canines and congenital anomalies across sagittal malocclusion groups. Such visual analytic tools are highly beneficial in both research and clinical practice, as they enable rapid recognition of high-risk malocclusion categories and support evidence-based decision-making.

From a clinical standpoint, these findings emphasize the critical role of early radiographic screening during the mixed dentition phase, particularly in patients presenting malocclusion patterns associated with elevated risk. Implementing interceptive measures—including timely extraction of deciduous canines, space management, arch development, and vigilant monitoring of eruption pathways—can substantially reduce the likelihood of surgical exposure and prolonged orthodontic traction in later stages. Furthermore, malocclusion-specific risk stratification empowers orthodontists to tailor treatment plans, optimize biomechanical strategies, and mitigate potential iatrogenic complications such as root resorption and periodontal damage.^9–11

The present study contributes valuable population-specific evidence from Eastern India, a region where orthodontic epidemiological data remain scarce. Although the overall prevalence of impacted canines aligns with global findings, the malocclusion-specific variations observed underscore the need to contextualize orthodontic diagnosis within both population characteristics and skeletal frameworks.

Despite its strengths, the cross-sectional design of the study restricts the ability to establish causal relationships. Future longitudinal investigations incorporating larger sample sizes and detailed growth pattern analyzes are warranted to further clarify the etiological mechanisms underlying canine impaction and to evaluate treatment outcomes across different impaction patterns. Additionally, the use of panoramic radiographs instead of CBCT may limit precise three-dimensional localization.

Overall, the findings highlight that impacted maxillary canines should not be regarded as isolated eruption anomalies, but rather as conditions intricately associated with malocclusion type, skeletal configuration, and developmental influences. Awareness of these interrelationships facilitates earlier diagnosis, supports targeted interceptive strategies, and ultimately enhances orthodontic outcomes by reducing complexity and improving treatment efficiency.^{12, 13}

The overall frequency observed (33.2%) is higher than population-based reports, likely due to the orthodontic nature of the sample. Therefore, these findings represent the frequency within a clinical cohort rather than true population prevalence, and should be interpreted accordingly.

Conclusion

The frequency within an orthodontic cohort, and the eruption patterns of impacted maxillary canines vary significantly across sagittal malocclusion classifications. Class I malocclusion contributed the highest number of cases, whereas Class III malocclusion demonstrated the highest within-group frequency, indicating greater relative risk. Class I malocclusion demonstrated the highest frequency of canine impaction, whereas Class III malocclusion was more strongly associated with congenital dental anomalies. These findings underscore the importance of malocclusion-specific screening protocols and individualized orthodontic treatment planning. Early detection and timely interceptive measures can shorten treatment duration, minimize complications, and enhance both functional efficiency and esthetic outcomes.

Footnotes

Accountability Statement

All authors have made substantial contributions to the work reported in this manuscript and meet the authorship criteria as per ICMJE guidelines. All authors have reviewed and approved the final version of the manuscript and agree to be accountable for all aspects of the work, ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Authors Contribution

Dr. Deepak Chauhan: Conceptualization and study design, data collection, data analysis and interpretation, manuscript drafting, and critical revision of the manuscript.

Dr. Sanjeev Datana: Study design, supervision, data interpretation, and critical revision of the manuscript for important intellectual content.

Dr. Anurag Rai: Methodology guidance, supervision, and validation of results.

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Ethical Approval and Informed Consent

Ethical approval was obtained from the Institutional Ethics Committee. As this was a retrospective study using existing records, the requirement for informed consent was waived by the ethics committee.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Deepak Chauhan

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