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Article

Evaluation of Morphology and Prevalence of Palatoradicular Grooves on Affected Maxillary Anterior Teeth Using Cone-Beam Computed Tomography: An Institutional Retrospective Study

by
Dilara Baştuğ
* and
Leyla Benan Ayrancı
Department of Endodontics, Faculty of Dentistry, Ordu University, Altınordu 52200, Ordu, Türkiye
*
Author to whom correspondence should be addressed.
Appl. Sci. 2025, 15(14), 8031; https://doi.org/10.3390/app15148031
Submission received: 12 June 2025 / Revised: 15 July 2025 / Accepted: 16 July 2025 / Published: 18 July 2025
Browse Figures
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Abstract

This retrospective study aimed to evaluate the prevalence, morphological types, and distribution patterns of palatoradicular grooves (PRGs) in maxillary anterior teeth using cone-beam computed tomography (CBCT) in a Turkish population. CBCT images of 1553 patients from the radiology archive of Ordu University Faculty of Dentistry (2021–2022) were reviewed. A total of 920 patients (4012 teeth) met the inclusion criteria. The presence, type, and localization of PRGs were assessed. Groove types were classified as Type 1, 2, 3A, or 3B; localization was recorded as mesial, distal, or midpalatal. Bilateral and unilateral occurrences were also analyzed. Statistical analysis involved chi-square tests, Tukey’s HSD, and Cohen’s kappa for intra-observer reliability. PRGs were detected in 23.6% of patients and 10.42% of teeth. Lateral incisors were most affected (87.56%). Type 1 grooves were most common (71.53%), with midpalatal localization being most frequent (54.07%). Bilateral grooves were significantly more prevalent than unilateral ones (p < 0.001). No significant association was found between groove type and tooth type or between gender and bilaterality. This study revealed a high prevalence of PRGs, especially in maxillary lateral incisors, with a significant tendency toward bilateral and midpalatal presentation. CBCT proved essential for detecting palatoradicular grooves, aiding diagnosis and treatment.

1. Introduction

One of the most critical reasons for endodontic treatment failure is the overlooked diagnosis of anatomical and morphological variations in the roots and root canal systems. A commonly missed variation, often found in maxillary anterior teeth—especially in maxillary lateral incisors—is the palatoradicular groove, which is a developmental anomaly that can pose significant challenges during endodontic treatment [1].
First described as a radicular groove by Black in 1908 [2], the palatoradicular groove (PRG) has since been recognized under various terminologies as the distolingual groove [3], developmental radicular anomaly [4], cinguloradicular groove [1], palatal groove [5], radicular lingual groove [6,7], and palatoradicular groove [8], reflecting its complex morphology and clinical implications.
The etiology of PRGs is multifactorial and remains unclear. Possible causes include enamel epithelium infolding, Hertwig’s epithelial root sheath anomalies [9], variants of dens invaginatus or genetic factors [10,11], and failed attempts to form an additional root [4,12]. Although some authors have mentioned a possible genetic contribution to palatoradicular groove formation [13], no controlled studies have demonstrated a hereditary pattern; thus, current evidence remains inconclusive.
A PRG normally begins in the region of the central fossa or in the cingulum, and its extension may be limited to the dental crown or involve the root surface, proceeding in a distal, midpalatal, or mesial direction [5].
PRGs are typically located on the palatal root surface, but labial involvement, though rare, has been reported, primarily in maxillary central incisors [14,15]. Some cases also show both labial and palatal grooves [16].
Palatoradicular grooves are classified into three types based on the criteria proposed by Gu and Tan:
Type I—a short groove limited to the coronal third of the root.
Type II—a long but shallow groove extending beyond the coronal third, typically associated with a normal or simple root canal morphology.
Type III—a long and deep groove extending beyond the coronal third, which may be further divided into two subtypes:
Type IIIa—a long and deep groove corresponding to a C-shaped canal system.
Type IIIb—a long and deep groove involving two separate root canals with normal morphology and apices, representing a labial groove connected to a palatal groove [17,18] (Figure 1).
A PRG can compromise the integrity and prognosis of the affected teeth, which makes the early diagnosis of this morphological alteration important to reduce the risk of complications [19]. Shallow, short palatoradicular grooves are usually innocuous, whereas deeper, more elongated grooves can create a pathway for infection, predisposing the tooth to pulp necrosis, periapical pathology, sinus-tract formation, periodontal pocketing and progressive alveolar bone loss via the apex, accessory foramina, lateral canals, and dentinal tubules [20].
Three-dimensional cone-beam computed tomography is a noninvasive diagnostic tool that helps provide three-dimensional anatomical configuration thereby facilitating diagnosis, classification, and treatment planning and improving treatment outcomes [21].
Recent studies have explored the use of cone-beam computed tomography as a tool for assessing the morphology and prevalence of dental structures [22]. These studies have demonstrated the reliability and accuracy of CBCT imaging for visualizing complex root canal anatomy and soft tissue structures in the dentogingival unit.
In this retrospective study, a CBCT-based evaluation was performed to determine the prevalence of palatoradicular grooves (PRGs) in maxillary anterior teeth within a Turkish population. The analysis included an assessment of gender-based distribution, the presence of unilateral or bilateral grooves, and detailed localization and classification based on radiographic features. Associations between groove type, tooth type, gender, and unilateral/bilateral presentation were statistically analyzed to provide clinically relevant insights for improved diagnosis and treatment planning. The null hypothesis of this study was that there is no statistically significant association between the characteristics of palatoradicular grooves (type, localization, laterality) and variables such as tooth type and gender.
Applsci 15 08031 g001
Figure 1. Sagittal and serial axial CBCT views of PRGs. (a–d) Sagittal reconstructions illustrating Type I, Type II, Type IIIA and Type IIIB grooves, respectively. (a1–a3,b1–b3,c1–c3,d1–d3) Corresponding axial slices at three root levels: 1 = coronal third, 2 = middle third, 3 = apical third, demonstrating the course of each groove. Red arrows highlight the PRG on each section (Reproduced from Zhang et al., 2022, with permission) [23].
Figure 1. Sagittal and serial axial CBCT views of PRGs. (a–d) Sagittal reconstructions illustrating Type I, Type II, Type IIIA and Type IIIB grooves, respectively. (a1–a3,b1–b3,c1–c3,d1–d3) Corresponding axial slices at three root levels: 1 = coronal third, 2 = middle third, 3 = apical third, demonstrating the course of each groove. Red arrows highlight the PRG on each section (Reproduced from Zhang et al., 2022, with permission) [23].
Applsci 15 08031 g001

2. Materials and Methods

2.1. Study Sample

CBCT scans of 1553 patients (671 males, 882 females) were retrieved from the Oral and Diagnosis and Radiology Department at Ordu University Faculty of Dentistry in Ordu, Turkey, between January 2021 and December 2022. This retrospective study was approved by the Ethics Committee of Ordu University (decision date, meeting number and decision number: 26.02.2025/04/56). From this pool of CBCT scans, 920 images of patients (388 male, 532 female) aged 12 to 78 years (mean ± standard deviation (SD) = 34.68 ± 13.18) who attended the University Dental Hospital were included in this retrospective study. This retrospective study was conducted based on the radiographic assessment of the available CBCT digital images that had been previously obtained from the dental records at the University Dental Hospital. These CBCT scans were not acquired specifically for the purposes of the current investigation but rather for other pre-existing diagnostic needs of the patients.
The CBCT radiographs were acquired using a KaVo OP 3D Vision system (Kavo Dental, Biberach, Germany), with the following technical parameters: 125–400 μm voxel size, 4.8–26.9 s scan time/exposure time, 90–120 kVp, and 3–8 mA. OnDemand 3D software (version 1.0.10.7462) was then utilized for the examination and analysis of the CBCT images.

2.2. Sample Size Estimation

The sample size for this retrospective study was determined using G*Power software (Version 3.1), with the aim of ensuring sufficient statistical power to detect meaningful findings. A power analysis was performed using an effect size of 0.197, derived from a reference study [24], with a 5% margin of error and 95% power. The required sample size was calculated to be 537 patients, ensuring sufficient statistical power to detect meaningful associations. However, to enhance the robustness and generalizability of the findings, the researchers decided to increase the sample size to 1.553.

2.3. Inclusion and Exclusion Criteria

The inclusion criterion was having at least one maxillary anterior tooth. Low-quality CBCT images with artifacts or scattering, as well as teeth with crown restorations, root canal fillings, posts, resorption, or deep caries/restorations, were excluded due to their potential to introduce significant artifacts affecting radiographic accuracy. Additionally, primary teeth, impacted teeth, and those with orthodontic braces were excluded for their impact on scan quality and interpretability. After applying these criteria, 920 CBCT scans were included, while 633 were excluded (Figure 2).

2.4. Image Assessment

The sole observer (DB) (Research Assistant in Endodontics) carried out all observations and measurements twice, with a two-week interval between the two sessions. If there was any uncertainty, a second evaluator [Associate Professor (LBA)] was requested to perform an additional assessment, and the examiners then engaged in further discussions to reach a final consensus.
To assess the presence and morphology of palatoradicular grooves, the CBCT images were carefully evaluated in the axial, coronal, and sagittal planes using OnDemand 3D software.
For calibration purposes, a detailed description of the CBCT figures of PRGs from previous reports [17,25] was prepared by the examiner (DB) to standardize the examination protocol. Axial sections were mainly used for the evaluation of PRGs along with other sections.
All readings were performed on a Dell Vostro 3670 computer (Dell Technologies Co., Inc., Round Rock, TX, USA) on a 22-inch screen with a resolution of 1920 × 1080 pixels.
This study collected data on the patients’ age and sex, tooth number (13, 12, 11, 21, 22, 23), whether palatoradicular grooves were present or absent, if the grooves were bilateral or unilateral, the groove type [Types 1, 2, 3A, 3B; [17]], and the location of the grooves (mesial, distal, midpalatal) (Figure 1).

2.5. Statistical Analysis

This study utilized a thorough statistical analysis approach to examine the associations between patient characteristics, tooth location, and the presence, type, and location of palatoradicular grooves. Initial descriptive statistics (mean, standard deviation for continuous variables; frequencies and percentages for categorical variables) were calculated to summarize the age, sex, and specific teeth of the patients. This provided a comprehensive overview of the patient demographics and the distribution of the observed palatoradicular grooves across the sample.
Chi-square tests (or Fisher’s exact test for cells with expected counts less than 5) were utilized to examine the associations between categorical variables such as sex, tooth number, presence (absent/present) and type of PRG (Types 1, 2, 3A, 3B), and its localization (mesial, distal, midpalatal), alongside the bilateral/unilateral manifestation of the PRG.
To further explore the specific differences revealed by the chi-square tests, the researchers conducted Tukey’s Honest Significant Difference (HSD) post hoc analysis. Using R statistical software (version 3.6.1), the Tukey HSD test provided a detailed examination of the significant variations observed.
This multi-stage statistical analysis approach provides an in-depth understanding of the investigation.
The intra-examiner reliability was assessed using the Cohen’s kappa test, with an overall kappa value of 0.87.
The researchers set the threshold for statistical significance at p < 0.05.

3. Results

Data from CBCT examinations of 8012 teeth in 1553 patients (671 males, 882 females) between 12 and 78 years (mean ± standard deviation (SD) = 34.68 ± 13.18) were analyzed retrospectively. CBCT images of 633 patients were excluded and 920 patients (4012 teeth) were included. The distribution of the evaluated parameters is presented in Figure 3.
The prevalence of PRGs was slightly higher in males (98 patients, 25.3%) compared to females (119 patients, 22.4%). However, a chi-square test of independence revealed no statistically significant difference between genders in terms of PRG prevalence (p = 0.347). In the patient-level analysis of PRG distribution, unilateral cases were observed in 59 patients (27.2%), while bilateral cases were more prevalent, observed in 158 patients (72.8%). A chi-square test revealed a statistically significant difference between unilateral and bilateral distributions (p < 0.001). When analyzed by gender, unilateral distribution was slightly higher in females (6.77%) compared to males (5.93%), while bilateral cases were more frequent in males (19.33%) than in females (15.6%). However, a chi-square test revealed no statistically significant association between gender and the unilateral/bilateral distribution (p = 0.335) (Table 1).
In our study, the chi-square test conducted to evaluate the distribution of PRG across different tooth types revealed a statistically significant association between tooth type and the prevalence of PRGs (p < 0.001). Chi-square analysis revealed a statistically significant difference in the prevalence of unilateral and bilateral PRGs at the tooth level (p < 0.001). The bilateral PRG was markedly more common than the unilateral PRG across all examined teeth. Chi-square analysis showed no significant association between tooth type and bilaterality (p = 0.708) (Table 2).
The initial chi-square test revealed a non-homogeneous distribution of groove types associated with PRGs (p < 0.001). Type 1 grooves were the most prevalent, observed in 299 teeth (71.5%). A post hoc analysis using Bonferroni correction confirmed that the prevalence of Type 1 grooves was significantly higher compared to Type 2 (67 teeth, 16.0%, corrected p < 0.001), Type 3A (45 teeth, 10.8%, corrected p < 0.001), and Type 3B (7 teeth, 1.7%, corrected p < 0.001).
This dominance was further validated by comparing Type 1 grooves to all other types combined, showing a significant difference (p < 0.05). In contrast, chi-square analysis revealed no significant association between tooth type and groove type (p = 0.091) (Table 3).
A chi-square test revealed that the localization distributions were statistically significant (p < 0.001). Midpalatal grooves were found to be the most prevalent localization type overall, with a statistically significant predominance. Pairwise comparisons showed that midpalatal grooves were significantly more frequent than mesial grooves (p = 0.0379, Bonferroni-corrected), and both midpalatal and mesial grooves were significantly more frequent than distal grooves (p < 0.001, Bonferroni-corrected). Midpalatal grooves were most common, significant in central teeth (p < 0.001) but not in lateral teeth (p = 0.152), with even distribution in canines (p = 1.0) (Table 4).

4. Discussion

Prevalence studies are essential for understanding the distribution and risk factors of rare dental anomalies like the palatoradicular groove, a variation in maxillary anterior teeth linked to periodontal and endodontic issues. These studies aid in early diagnosis and improved treatment strategies. The null hypothesis, namely, that no differences exist in the prevalence or distribution of palatoradicular grooves across maxillary anterior teeth, was rejected (p < 0.05).
This study is one of the most comprehensive retrospective analyses of PRG prevalence and morphology using CBCT imaging, aiming to establish advanced statistical connections, such as localization/tooth type and unilateral/bilateral distribution. While Zhang et al. included a larger sample size and focused on similar parameters [23], our study’s originality lies in its detailed statistical relationships, offering unique insights into the epidemiology and distribution patterns of PRGs.
CBCT was chosen for this study due to its ability to provide detailed three-dimensional perspectives, crucial for evaluating PRG dimensions and spatial relationships [26,27]. Axial views, highlighted by Tan et al., were particularly effective in capturing subtle morphological features that are challenging to detect with conventional methods [18]. While micro-CT offers sub-millimeter resolution and exceptional detail for groove analysis, as demonstrated by Mazzi-Chaves et al. (2022) and Gu et al. (2011), it is restricted to extracted teeth, making bilateral or population-level assessments impossible [17,28]. Similarly, in vitro studies, such as those by Kogon and Everett & Kramer, often lack clinical relevance and are prone to selection bias due to reliance on extracted teeth without detailed inclusion criteria [3,8]. On the other hand, traditional in vivo methods, relying on two-dimensional radiographs or clinical examinations (e.g., [29,30]), fail to capture subtle morphological variations and contralateral grooves, leading to potential underreporting. CBCT bridges these gaps by providing sufficient resolution for anatomical detail while allowing comprehensive bilateral and in vivo assessments. This combination makes CBCT an ideal choice for our study, enabling large-scale analysis with both clinical applicability and diagnostic precision.
The prevalence of palatoradicular grooves (PRGs) varies significantly across studies, primarily due to differences in study methodology, sample size, and the basis of prevalence calculation (tooth-based or patient-based). In our study, which analyzed 920 patients and 4012 maxillary anterior teeth using CBCT, a tooth-based prevalence of 10.42% and a patient-based prevalence of 23.59% were identified. This phenomenon aligns with findings from Demore et al., (2023), who observed a tooth-based prevalence of 5.9% but a patient-based prevalence of 21.67%, demonstrating that patient-based calculations often yield significantly higher prevalence rates due to multi-tooth involvement in individual patients [19]. To account for the differences in PRG prevalence across studies, it is essential to examine the key factors that contribute to these variations, such as sample size, methodology, inclusion of specific tooth types, and regional or ethnic differences.

4.1. Sample Size and Basis of Calculation

The difference in prevalence values across studies can also be attributed to sample size and whether the analysis was tooth-based or patient-based. For instance,
  • Zhang et al., (2022), in their CBCT study on 1715 Chinese patients, reported a patient-based prevalence of 8.4% and a tooth-based prevalence of 4.5% for lateral incisors [23].
  • Aljuailan et al. (2023) found a patient-based prevalence of 6.3% and a tooth-based prevalence of 1.3% in a study of 509 patients [24].
  • Aksoy et al. conducted a CBCT-based evaluation of 993 maxillary anterior teeth in 191 patients, reporting an overall prevalence of palatoradicular grooves (PGs) in 0.9% of teeth and 4.18% of patients [31].

4.2. Methodological Differences

The methodology used also significantly impacts prevalence findings.

4.2.1. CBCT Studies

CBCT offers a three-dimensional view, allowing precise detection of PRGs across multiple tooth types. Studies like Zhang et al. (2022), Arslan et al. (2014), and Ghahramani et al. (2018) used CBCT, reporting tooth-based prevalences of 4.5%, 1.4%, and 1.58%, respectively [23,25,32]. The relatively lower rates in these studies could be linked to smaller datasets [25,32] or inclusion criteria limited to incisor teeth only [23].
Yıldırım & Kamali’s (2025) incisor-only prevalence CBCT study (9.4% of patients) and our broader anterior-tooth series (23.6%) agree on two key points in a Turkish population: Type I grooves predominate and maxillary lateral incisors are most frequently affected; the main contrast lies in overall prevalence, which is higher in our larger sample [33].

4.2.2. In Vivo Studies Without CBCT

Studies relying on clinical examination, such as Withers et al. (1981) and Pécora et al. (1992), reported lower prevalences, such as 2.33% and 3.9, respectively, likely due to limitations in identifying subtle anatomical features without advanced imaging [11,34].

4.2.3. In Vitro Studies

In vitro studies, including Everett and Kramer (1972) and Kogon (1986), which examined extracted teeth, reported prevalence rates of 3.2% and 4.6%, respectively [3,8]. These rates may underestimate true prevalence due to selection bias, as extracted teeth are often collected for specific clinical reasons, such as periodontal disease, skewing the sample.

4.3. Sample Composition

The inclusion of specific tooth types also influences prevalence estimates:
  • Studies analyzing only lateral incisors (e.g., Iqbal et al. (2011), Hamagharib et al., Alam et al.) often report higher prevalences, such as 10% and 20% respectively, as lateral incisors are more frequently affected by PRGs [29,35].
  • Withers et al. (1981) also noted a prevalence of 8.5% in maxillary incisors [11].
  • Arslan et al. reported an overall prevalence of radicular grooves (RGs) of 1.4% in incisors and 0.9% in all anterior teeth [25].
  • In studies including all maxillary anterior teeth, the prevalence is distributed across central incisors, lateral incisors, and canines, leading to slightly lower overall rates compared to lateral, incisor-only studies. However, despite including all maxillary anterior teeth, our study reported a higher prevalence of 23.59% at the patient level and 10.42% at the tooth level. This may be due to our larger sample size (920 patients, 4012 teeth), detailed CBCT evaluations detecting subtle grooves, and inclusive criteria ensuring a representative sample.

4.4. Ethnic and Geographic Differences

Ethnic and geographic variation may also influence prevalence. For example,
  • Withers et al. (1981) found no significant difference in PRG prevalence between White and Black populations [11].
  • Zhang et al. (2022) and Demore et al. (2023), conducting studies in Chinese and Brazilian populations, respectively, reported prevalences of 8.4% and 21.67% [19,23]. While this may suggest potential regional differences, it is important to note that. Demore et al. (2023) found no significant racial differences within their Brazilian cohort, indicating that other factors such as sample size, methodology, or population-specific anatomical traits might account for these variations.
In our study, the prevalence of PRGs was slightly higher in males (25.3%) compared to females (22.4%), but this difference was not statistically significant (p = 0.347). This aligns with studies such as Withers et al. (1981), Mahmood et al. (2019), and Ghahramani et al. (2018), which also found no significant gender differences [11,30,32]. However, Iqbal et al. (2011) and Zhang et al. (2022) reported a significantly higher prevalence in males [23,35], while Shrestha et al. (2014) observed a female predominance in coronal grooves [36]. These variations may stem from population-specific genetic or developmental factors, as well as methodological differences like sample size or imaging techniques.
Bilateral grooves were significantly more prevalent than unilateral grooves at both the patient level (72.8% vs. 27.2%, p < 0.001) and the tooth level (82.3% vs. 17.7, p < 0.001). This pronounced bilateral tendency contrasts with some earlier studies, such as Aljuailan et al. (2023) and Lekshmi et al. (2022), which reported higher unilateral prevalence [24,37]. However, Hamagharib et al. found that 45% of grooves were bilateral, and Mahmood et al. (2019) reported a higher bilateral prevalence of 62.2%, aligning more closely with our findings [29,30]. Furthermore, Zhang et al. (2022) observed bilateral PRGs in 93.3% of teeth associated with bone loss, highlighting the importance of thorough bilateral assessment [23].
The consistent bilaterality in our study suggests a unique epidemiological pattern influenced by developmental or genetic factors. Unlike in vitro studies [3,8,38], where detection of bilateral manifestation is impossible, CBCT enabled accurate three-dimensional assessment.
In our study, a chi-square test revealed no statistically significant association between gender and the unilateral/bilateral distribution (p = 0.335). Zhang et al. also reported observations of bilateral PRGs in both males and females but did not statistically analyze the relationship between gender and unilateral/bilateral presentation [23]. These findings collectively suggest no clear gender-related pattern in PRG distribution.
Chi-square analysis showed no significant association between tooth type and bilaterality (p = 0.708). The higher prevalence of bilateral PRGs in lateral incisors is likely due to their larger representation in the sample.
Regarding groove types, our study identified Type 1 grooves as the most prevalent (71.53%), followed by Type 2 (16.03%), Type 3A (10.77%), and Type 3B (1.67%). This distribution aligns with Mahmood et al. (2019) and Alkahtany et al. (2022), who reported Type 1 as the dominant groove type (65.3% and 69.2%, respectively) [30,39], and Varun et al. (2022), who found Type 1 in 58.3% of cases [21]. These findings underscore the clinical importance of Type 1 grooves and suggest that they should be a focus of diagnostic and treatment strategies. Gu et al. (2011) and Zhang et al. (2022) highlighted the clinical significance of rarer groove types, such as Type 3B, which are linked to severe periodontal complications and complex root anatomy [17,23]. Mazzi-Chaves et al. (2022) further emphasized the anatomical variability of grooves, with micro-CT revealing deeper points in certain groove types, particularly Type 3B [28].
While no significant association between groove type and tooth type was observed in our study (p = 0.182, Bonferroni-corrected), the predominance of Type 1 grooves may have masked subtle relationships.
Localization analysis in our study revealed a significant predominance of midpalatal grooves (54.07%), followed by mesial (42.11%) and distal grooves (3.83%). This finding aligns with previous research, including Varun et al. and Lekshmi et al., who both reported midpalatal grooves to be the most common with significant positional variation [21,37]. Midpalatal grooves consistently emerge as the most frequent localization in PRG morphology, as highlighted by Demore et al. (2023), Zhang et al. (2021), and Pécora et al. (1992) [19,23,34]. Studies like Albaricci et al. (2008) and Hou et al. (1993) further reinforce their centrality, emphasizing their diagnostic and biomechanical significance [38,40]. In this study, midpalatal grooves were most common, with a significant difference in central teeth (p < 0.001), no difference in lateral incisors (p = 0.152), and even distribution in canines (p = 1.0), reflecting their overall lower prevalence of PRGs. These findings highlight the variability in groove localization and its potential clinical implications for diagnosis and treatment planning.
The findings of this study underscore the importance of early detection and management of palatoradicular grooves (PRGs) in clinical practice. The predominance of Type 1 grooves highlights the necessity for heightened diagnostic awareness, as these grooves, despite their relative simplicity, can harbor plaque and calculus, leading to localized periodontal destruction. Rarer groove types, such as Type 3B, pose additional challenges due to their association with severe periodontal bone loss and complex root anatomy, complicating endodontic treatment, as emphasized by Gu et al. (2011) and Zhang et al. (2022) [19,23].
PRG detection plays a vital role in guiding treatment decisions. Simple cases may only require routine care, such as cleaning and monitoring, whereas severe grooves, particularly Type 3B, often necessitate specialized procedures, including root-surface surgery, regenerative therapies, or even combined periodontal and endodontic approaches. CBCT imaging proved instrumental in this study, offering the detailed visualization needed to craft precise and individualized treatment solutions.
Treatment considerations by PRG-type CBCT visualization is invaluable for tailoring therapy to groove depth and complexity. Type 1 PRGs can usually be managed with odontoplasty or shallow saucerization followed by sealing with glass-ionomer composite or a calcium-silicate cement to eliminate the plaque niche [41]. Type 2 PRGs benefit from a papilla-preserving or apically positioned flap for thorough debridement; the groove is smoothed or filled and a regenerative aid such as bone graft, enamel matrix derivative, PRP, or membrane is added to re-establish attachment [42,43,44]. Type 3A/3B PRGs require combined endodontic therapy plus surgical access to clean and seal the groove; in extensive lesions, intentional replantation or orthodontic extrusion allows extra-oral sealing, with ≈88% two-year survival [45]. Successful outcomes in severe (especially Type 3B) cases also depend on concurrent periodontal treatment to eradicate external biofilm [46,47]. Thus, while simple grooves may need only routine cleaning and monitoring, complex forms often demand root-surface surgery and advanced regenerative or combined perio–endo approaches; CBCT is essential for planning these individualized interventions.
This study provides a comprehensive evaluation of PRGs using a large dataset and advanced CBCT imaging. The inclusion of maxillary canines, often overlooked in previous studies, offers a more complete analysis of PRG prevalence across anterior teeth. Additionally, the use of robust statistical methods ensures reliable results, while the detailed analysis of groove type and bilaterality provides valuable insights for clinical practice. These strengths highlight this study’s contribution to improving the diagnosis and management of PRGs.

4.5. Limitations and Recommendations

The limitation of this study is the reliance on CBCT imaging, which, while highly accurate, may not be accessible in all clinical settings, potentially limiting its generalizability. Additionally, this study’s cross-sectional design provides a snapshot of PRG prevalence but does not allow for the assessment of how these anatomical features progress or impact periodontal and endodontic health over time. The relatively low prevalence of rarer groove types, such as Type 3B, may have reduced the statistical power to identify subtle associations with clinical outcomes.
Future studies should explore larger, more diverse populations to validate these findings and investigate potential regional or genetic influences on PRG prevalence. The use of AI-based diagnostic tools could further enhance the detection and classification of PRGs, improving early diagnosis and treatment planning.

5. Conclusions

In conclusion, our study provides a comprehensive evaluation of PRGs, highlighting their anatomical, epidemiological, and clinical significance. The use of CBCT imaging enabled precise groove localization, classification, and bilaterality assessment.
In conclusion, CBCT examination of 4012 maxillary anterior teeth in 920 Turkish patients revealed a PRG tooth-based prevalence of 10.42% and a patient-based prevalence of 23.59% with no sex difference. These quantitative data reinforce the anatomical, epidemiological, and clinical importance of PRGs and demonstrate the value of CBCT for precise localization, classification, and bilaterality assessment. The findings emphasize the critical role of advanced imaging in understanding PRGs and their contribution to periodontal and endodontic pathologies. Future studies should build on these insights, exploring the biomechanical and developmental aspects of PRGs to improve diagnosis and treatment.

Author Contributions

L.B.A. designed the study. D.B. and collected the data and performed the statistical analysis. L.B.A. and D.B. interpreted the results and wrote the manuscript. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

This retrospective study was approved by the Non-Interventional Clinical Research Ethics Committee of Ordu University (approval date: 26 February 2025, meeting number: 04, decision number: 56). The requirement for written informed consent was waived due to the retrospective nature of the study. All procedures involving human participants were conducted in accordance with the ethical standards of the institutional research committee and with the 1964 Declaration of Helsinki and its later amendments. CBCT scans were obtained with written informed consent, which included permission for anonymized use of clinical and radiological data for scientific, educational, and research purposes. Due to the retrospective nature of this study and the scope of the original consent, no additional informed consent was required for inclusion in this research.

Informed Consent Statement

The study was conducted in compliance with human ethics standards. Written informed consent for CBCT imaging was obtained from all participants. Specific consent for retrospective analysis was waived as per the ethics approval.

Data Availability Statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Conflicts of Interest

The authors declare that they have no competing interests.

Abbreviations

The following abbreviations are used in this manuscript:
PRGPalatoradicular groove
CBCTCone-beam computed tomography
AIArtificial intelligence

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Applsci 15 08031 g002
Figure 2. Flowchart of patient selection and classification.
Figure 2. Flowchart of patient selection and classification.
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Figure 3. (a) Groove type distribution; (b) groove localization; (c) affected tooth type; (d) unilateral vs. bilateral (patients); (e) PRG prevalence by gender.
Figure 3. (a) Groove type distribution; (b) groove localization; (c) affected tooth type; (d) unilateral vs. bilateral (patients); (e) PRG prevalence by gender.
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Table 1. Distribution of PRG according to gender and unilateral/bilateral manifestation.
Table 1. Distribution of PRG according to gender and unilateral/bilateral manifestation.
GenderPatients ExaminedPatients with PRGUnilateralBilateral
Female532119 (22.37%)36 (6.77%)83 (15.6%)
Male38898 (25.26%)23 (5.93%)75 (19.33%)
Total920217 (23.59%)59 (6.41%)158 (17.17%)
p value-0.3470.335<0.001 *
* Statistically significant association between the occurrences of unilateral versus bilateral PRG manifestations in patient base analysis (p < 0.001).
Table 2. Distribution of PRGs by tooth type and unilateral/bilateral manifestation.
Table 2. Distribution of PRGs by tooth type and unilateral/bilateral manifestation.
Tooth TypeTeeth with PRG (%)Unilateral PRGsBilateral PRGs
Maxillary central incisor40 (9.57%)10 (2.39%)30 (7.18%)
Maxillary lateral incisor366 (87.56%)60 (14.35%)306 (73.21%)
Maxillary canine12 (2.87%)4 (0.96%)8 (1.91%)
Total41874 (17.7%)344 (82.3%)
p value<0.001 1—<0.001 2
1 Statistically significant difference among different tooth types in terms of presence of PRGs (p < 0.001). 2 Statistically significant association between the occurrences of unilateral versus bilateral PRG manifestations in teeth base analysis (p < 0.001).
Table 3. Distribution of PRGs by groove type.
Table 3. Distribution of PRGs by groove type.
Tooth TypeTeeth with PRG (%)Type 1Type 2Type 3AType 3B
Maxillary central incisor40 (9.57%)35 (8.37%)1 (0.24%)4 (0.96%)-
Maxillary lateral incisor366 (87.56%)253 (60.53%)66 (15.79%)40 (9.57%)7 (1.67%)
Maxillary canine12 (2.87%)11 (2.63%)-1 (0.24%)-
Total418299 (71.53%)67 (16.03%)45 (10.77%)7 (1.67%)
p value<0.001 1<0.001 2<0.001 3<0.001 4—
1 Statistically significant difference in groove type distribution (p < 0.001). 2 Type 1 vs. Type 2 (p < 0.001). 3 Type 1 vs. Type 3A (p < 0.001). 4 Type 1 vs. Type 3B (p < 0.001).
Table 4. Distribution of PRGs by groove location.
Table 4. Distribution of PRGs by groove location.
Tooth TypeTeeth with PRG (%)MesialDistalMidpalatal
Maxillary central incisor40 (9.57%)8 (1.91%)1 (0.24%)31 (7.42%)
Maxillary lateral incisor366 (87.56%)164 (39.23%)11 (2.63%)191 (45.69%)
Maxillary canine12 (2.87%)4 (0.96%)4 (0.96%)4 (0.96%)
Total418176 (42.11%)16 (3.83%)226 (54.07%)
p valuep < 0.001 10.037 2<0.001 3<0.001 3
1 Statistically significant variations in PRG localization (p < 0.001). 2 Midpalatal vs. mesial (p = 0.037). 3 Statistically significant difference between midpalatal vs. distal and mesial vs. distal (p < 0.001).
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Baştuğ, D.; Ayrancı, L.B. Evaluation of Morphology and Prevalence of Palatoradicular Grooves on Affected Maxillary Anterior Teeth Using Cone-Beam Computed Tomography: An Institutional Retrospective Study. Appl. Sci. 2025, 15, 8031. https://doi.org/10.3390/app15148031

AMA Style

Baştuğ D, Ayrancı LB. Evaluation of Morphology and Prevalence of Palatoradicular Grooves on Affected Maxillary Anterior Teeth Using Cone-Beam Computed Tomography: An Institutional Retrospective Study. Applied Sciences. 2025; 15(14):8031. https://doi.org/10.3390/app15148031

Chicago/Turabian Style

Baştuğ, Dilara, and Leyla Benan Ayrancı. 2025. "Evaluation of Morphology and Prevalence of Palatoradicular Grooves on Affected Maxillary Anterior Teeth Using Cone-Beam Computed Tomography: An Institutional Retrospective Study" Applied Sciences 15, no. 14: 8031. https://doi.org/10.3390/app15148031

APA Style

Baştuğ, D., & Ayrancı, L. B. (2025). Evaluation of Morphology and Prevalence of Palatoradicular Grooves on Affected Maxillary Anterior Teeth Using Cone-Beam Computed Tomography: An Institutional Retrospective Study. Applied Sciences, 15(14), 8031. https://doi.org/10.3390/app15148031

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