Understanding any variations in the shape of canals is essential for endodontic treatment.22 It helps us foresee potential complications and enables us to successfully remove necrotic material and pulp tissue without endangering the tooth's or root's structural integrity.23 The current study focuses on the root canal morphology of permanent maxillary and mandibular canines to overcome potential problems related to root canal treatment and enhance the clarity of canal morphology classification.
In all, there were not any statistically significant differences between males and females regarding the number of roots in maxillary and mandibular canine teeth, respectively, and combined (p > 0.05). Mashyakhy et al.24 reported similar findings for both the maxillary and mandibular teeth as a whole. Both studies found that canine teeth often have a single root. A higher prevalence of two-rooted canines was noted in the mandible. We found that two-rooted canines were present in 0.3% of the upper jaw and 2.5% of the lower jaw in our research. Supporting these data, Mashyakhy et al.24 found two-rooted canines in 2.2% of the maxilla and 5.2% of the mandible. In a study conducted in 2022 in the Saudi population25, the rate of detection of two roots in mandibular canines was found to be 5%. When examining studies in the literature, it has been observed that the rates of two-rooted canine teeth vary between 0% and 15.1% across different ethnic groups.25–30
In this study, according to the Vertucci classification, the most common root canal patterns in maxillary canine teeth are Type I (right maxilla: 96.4%; left maxilla: 95.6%), Type III (right maxilla: 1.6%; left maxilla: 2.0%), and Type V (right maxilla: 1.4%; left maxilla: 1.6%), respectively. Mashyakhy et al. (81.6%)31, Vertucci (100%)21, Pineda and Kuttler (100%)32, Calışkan et al. (93.48%)33, and Sert and Bayırlı (91% male and 96% female)3 reported similar findings in the literature, which identified Type I as the most prevalent root canal pattern in maxillary canine teeth. However, while the third most common canal morphology in our study was Type V, Type V canal configuration was not reported in the study by Pineda and Kuttler 32, Sert and Bayırlı3, and Vertucci21. Mashyakhy et al.31 showed the presence of a Type V canal configuration in the fourth place with a rate of 2%. If we classify these data according to the Ahmed et al.9 classification, the most frequently observed canal configuration is 1C1 (right maxilla: 80.8%, left maxilla: 41.2%). This is followed by the configuration 1C1–2−1 (right maxilla: 1.6%, left maxilla: 1.8%). The effect of age on dental anatomy has not been extensively studied. One study found that individuals over 65 years of age exhibited a higher proportion of more complex root canal structures compared to younger groups.27 Similar findings were reported by Karataslioglu and Kalabalik 34 in a Turkish cohort and by Martins et al.35 who studied age-related changes in root canal configurations using CBCT. However, previous studies in Turkish and Chongqing populations found that younger individuals more commonly had multiple canals compared to older individuals.26,36 In the present study, root canal morphologies were not found to vary according to the system of Vertucci et al.8 and Ahmed et al.9
Although there are various differences between the studies on mandibular canine teeth based on the Vertucci classification, the most common canal morphology was observed as Type I, similar to our study.21,31,37 The second most common canal morphology in our study was Type III. Despite Mashyakhy et al. 31 and Çalışkan et al. 33 having similar results, Vertucci 21 reported the second most common canal type as Type II. While it was not reported by Mashyakhy et al.31, Type IV canal morphology was observed at 2% in the current study. Further, Pecora et al.37 reported Tip IV canal morphology as 1.2% in their study. When assessed by the Ahmed et al. classification, the most common canal morphology is 1C1 (right mandibula: 82.0%, left mandibula: 81.6%), followed by 1C1–2−1 (right mandibula: 2.6%, left mandibula: 4.6%), respectively. For all canines, more than 10% morphology that did not fit the classification of Vertucci et al.21 was detected in this study.
The effect of gender on root number and morphology, this study also found that the number of roots did not differ according to gender, similar to some studies in the literature.25,30,31,38 However, there are also studies in the literature indicating that canine teeth with two roots are more dominant in males.39,40 In two study conducted in the same population as this study 3,41,42, it was stated that the root morphology of mandibular canine teeth did not vary according to gender. However, Taha et al.43 claimed that males have more complex root canal systems than females. Variations in the outcomes of studies may be due to factors like the size of the sample, the methods used, or the genetic characteristics of the participants in the study.
There are publications in the literature that age significantly affects the morphology of permanent teeth.43 However, in this study, age was found to have no effect on the morphology of canine teeth evaluated with the two systems, except for the left maxillary canines. Complex root morphology was statistically more common in the 21–30 age group than in the 31–40 age group in the left maxillary canines (p < 0.05). These results in consistent with the studies conducted in Chinese, Turkish and Malaysian populations in terms of complexity.26,30,36,44 Consistent with this study, Almohaimede et al.27 found also that the number of roots did not vary according to age groups.
The Vertucci classification is a long-standing and user-friendly approach that we utilized in this study to evaluate categorization systems.21 Nevertheless, the Vertucci categorization has drawbacks. These failures involve not reporting intricate root-canal structures such root number, auxiliary canals, root fusion, and dental anomalies.9,45 We found that the Vertucci categorization is insufficient for categorizing root-canal configurations within the "other" category. The term "other" in this study refers to accessory canals and complex morphology. The Ahmed et al. et al.46 classification contributes to the reporting of the localization and number of accessory canals observed under the heading "other" to give knowledge before treatment. With the only coding system used by Ahmed et al. et al.'s classification, it can identify root and canal structures, dental anomalies, and anatomical variations.9,46 Although this classification system is quite explicit and accurate in defining complex morphologies, it has the limitation of creating a greater number of unique codes and categories compared to previous classifications, which makes it complex.45,47
Since this work is managed from a single center, it would be more appropriate to conduct a multi-centric and broadened sample size to provide comprehensive information about the root-canal morphologies of the Turkish community. CBCT has lower spatial resolution than micro-CT and nano-CT when assessing intricate structures like root-canal morphology. This could have influenced the study's outcomes. The new classification method by Ahmed et al. 46 is crucial for gaining a comprehensive understanding of root-canal morphology. The inclusion of this novel system in undergraduate and graduate dental education could enhance comprehension of intricate subjects like root and canal morphology and decrease post-operative complications in clinical settings.