892 D3000 new imprint Word template Vol 13, No 1 (2025) ISSN 2167-8677 (online) DOI 10.5195/d3000/2025.892 http://dentistry3000.pitt.edu Apical Foramen Positional Variability and Its Minimal Distance from the Anatomical Apex in Premolars A CBCT-Based Analy.c Study Maysaloon S. Saeed1 1College of Medicine, University of Duhok, Iraq Abstract Objec1ves: This study aimed to determine the posi1on of the AF in rela1on to the root surfaces of human permanent premolar teeth in the region using cone-beam computed tomography (CBCT) imaging. Materials and Methods: A descrip1ve cross-sec1onal study was conducted using CBCT im- ages of 206 pa1ents from the Iraqi Kurdistan region. Mul1planar CBCT scans were analyzed to determine the AF posi1on rela1ve to the root canal surface of the premolars. The mean distance between the AF and anatomical apex was measured and compared between quadrants and sexes. Sta1s1cal analysis was performed using Fisher’s chi-square and t- tests, with a significance threshold set at p = 0.05. Results: The central AF loca1on was the most prevalent in premolars, followed by distal and mesial loca1ons. However, the central and mesial posi1ons were the most prevalent in the mandibular right second premolar. The mean AF-anatomic apex distance for the first premolars on the right side was 0.6205 mm. For the second premolars, the distances were 0.6205 mm in males and 0.5854 mm in females. No significant varia1ons were observed based on the parameters outlined in the methodology. Conclusion: The apical foramen was predominantly located centrally in the premolars, fol- lowed by the distal posi1on. To enhance the success rate of root canal therapy, a minimum of 1 mm safety margin from the anatomic apex in premolars is recommended to improve treatment outcomes. Open Access Cita%on: Maysaloon SS. (2025) Apical Foramen Posi- %onal Variability and Its Minimal Distance from the Ana- tomical Apex in Premolars: A CBCT-Based Analy%c Study. Den%stry 3000. 1:a001 doi:10.5195/d3000.2025.892 Received: March 30, 2025 Accepted: May 14, 2025 Published: June 10, 2025 Copyright: ©2025 Maysaloon SS. This is an open access ar%cle licensed under a Crea%ve Commons AUribu%on Work 4.0 United States License. Email: maysaloonshaman@gmail.com Introduc)on Complete cleaning and shaping of the root canals, along with a three-dimensional sealed root canal system (RCS) filling, are considered the most essential and widely practiced endodontic procedures worldwide [1]. Accurate morphological knowledge of the apical region is crucial, as instrumenta- tion and filling of root canals are based to a significant extent on this information [2,3]. Understanding the apical area and morphol- ogy of the tooth root canal is a complex and critical aspect that clinical practitioners must consider when making decisions during endodontic treatment [3]. Numerous factors contribute to the variations found in studies on root canals and apical foramina (AF), including ethnicity, age, and sex. A suc- cessful endodontic procedure commences with a comprehensive assessment of the root canals and their anatomical variability [1-3]. Apical Foramen PosiFonal Variability and Its Minimal Distance from the Anatomical Apex in Premolars Vol 1, No 1 (2012) DOI 10.5195/d3000/2025.892 http://dentistry3000.pitt.edu 2 Cone beam computed tomography (CBCT) is a valuable 3D orthogonal imaging tool for the maxillofacial skeleton and its internal struc- tures. It utilizes a lower dose of radiation compared to conventional CT [4] and has been demonstrated to be more accurate than digital X-rays in identifying RCS. It precisely determines root canal morphology and AF location in relation to the root surfaces, which requires exact identification during access preparation, and reduces errors and failures in endodontic treatments by elimi- nating the issue of root superimposition from neighboring anatomical structures. The precise assessment of the AF distance has proven to be a highly beneficial tool in clini- cal dental practice and must be taken into consideration during root canal procedures. Complete debridement of these regions through mechanical instrumentation is im- practical, and necrotic tissue remnants and microorganisms in the apical portion affect post-treatment outcomes [5]. CBCT images provide insight into the spatial resolution of anatomical variations and enable clinicians to visualize any necessary access modifica- tions for treatment. From an anatomical and clinical perspective, the narrowest part of the root canal is the apical constriction or mi- nor foramen. From this point, the canal grad- ually widens and terminates at the AF or ma- jor foramen. The cementodentinal junction is the histological landmark where the pulp ends and the periodontal ligament begins. It is expected to be located at the apical con- striction, but its position can be irregular (Figure 1). The AF is the main opening to the apical portion of the root canal and consti- tutes the site where endodontic filling is per- formed [6]. In numerous instances, the terms “apex” and “AF” have been used interchange- ably. The anatomical apex refers to the ana- tomical terminus of the root, as observed on radiography. In contrast, the AF is the main opening of the root canal in relation to the apex. The AF can be in mesial, distal, buccal, and lingual positions [7]. Recent studies have reported that in over 60% of canals, the AF is not located at the apex. Furthermore, the dis- tance between the AF and radiographic apex can vary by up to 3 mm [8]. This apical devi- ation of the foramen is attributed to aging and cementum deposition. Additionally, the degree of deviation varied according to tooth type. Over the past three decades, various methods, such as clearing, modeling, and his- tologic and radiographic techniques, have been employed to assess the structure of the root canal. Recently, the application of CBCT has increased significantly. CBCT can pro- vide 3D observations of anatomical struc- tures and pathological conditions [9]. Material and Methods The study protocol was approved by the In- stitutional Ethics Committee of the College of Dentistry, University of Duhok, Kurdistan Region, Iraq. The case records of 696 premo- lars from 206 patients (102 males and 104 females) who underwent CBCT scans be- tween November 2021 and September 2024 were retrieved from the databases of three private dental imaging centers located in three governorates in the Kurdistan Region of Iraq. In this retrospective study, CBCT im- ages of permanent premolar teeth from Duhok, Erbil, and Sulaymaniyah were in- cluded. To obtain a representative sample of the Kurdish population in this region, the main public dental clinic in the capital of these governorates was selected as the data collection setting. CBCT images were ob- tained using a NewTom Giano (Verona, Italy) CBCT system. Two types of software were used for image analysis and evaluation: Villa 3D Planner (Italy) for treatment planning and Anatomage I In Vivo Dental Viewer (It- aly) for 3D visualization. The machines were operated at 90 kVp and 10mA. The field of view was 8 × 8 cm, and the voxel size was 75 µm. Images in sections of 0.5 mm with intervals of 1 mm in the coronal and sagittal planes in terms of the 10 mm were prepared using NNT software for ap- propriate examination of the teeth. In the ax- ial view, only the lower one-third of the roots was investigated, and the roots were exam- ined horizontally (parallel to the occlusal surface) so that they passed through the up- per sections of the teeth and were parallel to the sagittal plane. In the first mode, images were cross-sectional or in the sagittal view, enabling examination of the buccal and lin- gual surfaces. In the second mode, the coro- nal view of the mesiodistal teeth was investi- gated. It is noteworthy that the AF may be positioned mesiodistally or buccolingually relative to the outer surface of the tooth. Consequently, in both the coronal and sagit- tal views, the distance between the AF and the perpendicular and tangential lines on the radiographic apex (in 10 mm) was measured using NNT software. Furthermore, the dis- tance from the AF to the anatomic apex was observed in the axial, sagittal, and coronal planes. Healthy teeth with no previous endo- dontic treatments, restorations, or root re- sorption were chosen as inclusion criteria. Teeth with open apices (not fully formed), root resorption, or calcification (partial or complete radiographic obliteration of the pulp chamber and root canals), as well as teeth with previous endodontic treatment, were excluded. Healthy teeth with no prior treatment or restoration were included. The images were evaluated, and the data were captured using Microsoft Excel 2016. The data were subsequently exported to the Sta- tistical Package for the Social Sciences (SPSS version 26, IBM Corp., IL, and USA). Chi-square test was used to compare propor- tions. Fisher’s exact test was used instead of the chi-square test when the expected value of more than 20% of the cells of the table was <5. Kolmogorov–Smirnov test, unpaired “t”, and paired “t” tests were used for sample comparison. The level of signikicance was set at 0.05. The results were presented using SPSS software, and the outcomes were rep- resented in the form of tables and bar charts. Results Six hundred and ninety-six premolars that met the specikic inclusion criteria and were from individuals between the ages of 18 and 60 were included in this study. The sample comprised 102 males (49.51%) and 104 fe- males (50.49%), as presented in (Table 1). Table 1. Prevalence of AF locations in maxillary premolar teeth in both genders. Tooth Type Loca- tion Male (%) Fe- male (%) Total (%) Right UFPT Cen- tral 58.3 51.1 54.7 Distal 37.5 42.2 39.8 Me- sial 4.2 6.7 5.5 Right USPT Cen- tral 69.2 66.7 68.0 Distal 28.2 31.1 29.6 Me- sial 2.6 2.2 2.4 Apical Foramen PosiFonal Variability and Its Minimal Distance from the Anatomical Apex in Premolars Vol 1, No 1 (2012) DOI 10.5195/d3000/2025.892 http://dentistry3000.pitt.edu 3 Left UFPT Cen- tral 53.2 47.9 50.5 Distal 44.7 52.1 48.4 Me- sial 2.1 0.0 1.1 Left USPT Cen- tral 54.1 63.4 58.7 Distal 40.5 29.3 34.9 Me- sial 5.4 7.3 6.4 For the right maxillary kirst premolar teeth (R.UFPT), the majority of apical foramina in both males and females were centrally lo- cated, accounting for 58.3% and 51.1%, re- spectively. The second most prevalent loca- tion was distal in both males and females, with percentages of 37.5% and 42.2%, re- spectively. The least common location was mesial, occurring in 4.2% of males and 6.7% of females. For the left maxillary kirst premo- lar teeth (L.UFPT), the distribution of the ap- ical foramina was relatively similar between males and females. The most frequent loca- tion was central, accounting for 53.2% in males and 47.9% in females. The second most common location was distal, observed in 44.7% of males and 52.1% of females. A minimal percentage of apical foramina was mesially located in males (2.1%). For the right maxillary second premolar teeth (R.USPT), the majority of apical foramina in both males and females were centrally posi- tioned, occurring in 69.2% and 66.7% of cases, respectively. The second most preva- lent location was distal, recorded in 28.2% of males and 31.1% of females. A minimal per- centage of apical foramina was mesially lo- cated in both males and females (2.6% and 2.2%, respectively). For the left maxillary second premolar teeth (L.USPT), the major- ity of apical foramina were centrally posi- tioned, observed in 54.1% of males and 63.4% of females. A smaller percentage was distally located in both males and females (40.5% and 29.3%, respectively), while the mesial location was the least common, oc- curring in 5.4% of males and 7.3% of females (Table 2). [refer to the last page for Table 2] By Fisher’s exact test. **By Chi-square test. LFPT: Lower First Premolar Teeth; LSPT: Lower Second Premolar Teeth. There is a statistically signikicant difference in the lo- cation of apical foramina between males and females, for the location of apical fo- ramina in the left kirst premolar teeth. The p-value for this location is 0.067, which is marginally signikicant at the 0.05 level. For the right mandibular kirst premolar teeth (R.LFPT), the majority of apical foramina were centrally located in both males and fe- males, comprising 58.1% and 53.5%, respec- tively. The second most prevalent location was the distal, occurring in 30.2% of males and 23.3% of females. The least frequent lo- cation was mesial, observed in 11.6% of males and 23.3% of females. For the left mandibular kirst premolar teeth (L.LFPT), the majority of apical foramina were cen- trally positioned, recorded in 48.8% of males and 72.7% of females. A smaller proportion was distally located in both males and fe- males (29.3% and 18.2%, respectively), while the least common location was mesial in both males and females (22% and 9.1%, respectively). The majority of apical foram- ina in the right mandibular second premolar (R.LSPT) were centrally situated in both males and females (65% and 58%, respec- tively). The second most prevalent location was mesial in both males and females (20% and 26%, respectively), while the least com- mon location was distal (15% and 16%, re- spectively). For the left mandibular second premolar teeth (L.LSPT), the central location was the most prevalent in both males and fe- males, occurring in 75.7% and 68.8% of the cases, respectively. The second most com- mon location was distal, observed in 16.2% of males and 22.9% of females, while the me- sial location exhibited the lowest percentage in both males and females (8.1% and 8.3%, respectively). The average (±standard deviation [SD]) dis- tance from the AF to the anatomic apex of the kirst and second premolars in males was 0.61–0.62 mm with ± SD of 0.142 and p=0.54 in the right and left quadrants, and for fe- males was 0.58–0.60 mm with ± SD of 0.129 and p=0.22 for both right and left quadrants. According to the t-test, no statistically signif- icant difference was observed in the distance between the AF and the anatomic apex of the kirst and second premolars in both the right and left quadrants (p = 0.857). A comparison of the mean distance between the AF and an- atomic apex of the kirst and second premo- lars between the right and left sides in both males and females is presented in Tables 3 and 4. Table 3. Comparison of mean distance be- tween apical foramen and anatomic apex of right kirst premolar and right second premo- lar between males and females (mm). Table 4. Comparison of mean distance be- tween apical foramen and anatomic apex of left kirst premolar and left second premolar be- tween males and females. Tooth Type Right (Mean ± SD) Left (Mean ± SD) p- value First premo- lars 0.62 ± 0.14 0.62 ± 0.14 0.86 Second premo- lars 0.6 ± 0.13 0.59 ± 0.12 0.28 Discussion A comprehensive understanding of root anatomy and canal morphology is essential for the efficient execution of biomechanical cleaning and shaping, which is crucial for achieving predictable endodontic outcomes. However, variations in root canal morphol- ogy present clinical challenges that may re- sult in unfavorable endodontic treatment outcomes. CBCT is an excellent ex vivo and in vivo method for evaluating external and in- ternal root morphology compared with con- ventional 2D radiography [6-9]. In the present study on the maxillary first premolars (R.UFPT and L.UFPT), the most prevalent deviation in the location of the ap- ical foramina in males and females was cen- tral (52.6%), followed by distal (44.1%) and mesial (3.3%). Variations were observed be- tween quadrants and genders for these teeth. No cases were recorded for females in the mesial location on the left side, and the distal location was more prevalent on the left side for both sexes than that on the right side. Similar results were also reported in a recent study conducted on the Brazilian population [9], which indicated that the most common AF location in the maxillary first premolars (39.9%) was central. In the present study, the most common location for the maxillary second right and left premolar teeth (R.USPT, L.USPT) was the central position, accounting for 63.4% of cases. This was fol- lowed by the distal (32.2 %) and mesial (4.4 %) locations. Almost all AF locations were consistent in both quadrants and both sexes, except for the distal location in the left upper second premolar tooth (L.USPT), which was more prevalent in males than in females. A similar result was reported in a study conducted on a subpopulation in Age group Mean ± Standard Devition Males Females p- value First pre- molars 0.62±0.14 0.59±0.12 0.544 Second premolars 0.62±0.14 0.58±0.11 0.204 Apical Foramen PosiFonal Variability and Its Minimal Distance from the Anatomical Apex in Premolars Vol 1, No 1 (2012) DOI 10.5195/d3000/2025.892 http://dentistry3000.pitt.edu 4 Yemen, which also indicated that the center was the most frequently observed location for the second upper premolars [10]. In a study conducted in Brazil [9], it was found that the most common location for AF among the second upper premolars was central, ac- counting for 57.4%. In the present study, the location of the AF for the lower first right and left premolars (R.LFPT, L.LFPT) in both sexes was predominantly in the center (58.3%), followed by distal (25.1%) and me- sial (16.6%). In the R.LFPT, the distal and central locations were similar between the sexes, but the mesial location was more prevalent in females than in males. However, in the left LFPT, the central location was more prevalent in females than in males, whereas mesial and distal locations were more prevalent in males than in females. These results were corroborated by other studies conducted in the Kuwaiti population [11] and Brazil [9], where the central loca- tion was found to be the most common among the sample studies of the mandibular first premolars. However, a specific sub- group within the Iranian population contra- dicted the present findings. They reported that the most common location for the apical foramina among mandibular first premolars was the distal [12]. Significant variations were observed among different populations, which may be attributed to factors such as sex, sample size, ancestry, data collection methods, and study design [13]. For the mandibular right and left second pre- molars (R.LSPT, L.LSPT) in our study, both sexes exhibited a predominant central loca- tion, accounting for 66.9% of the cases. This was followed by the distal (17.5 %) and me- sial (15.6 %) locations. The central location in both quadrants was more prevalent in males than females. On the right side, the me- sial and distal locations were approximately equivalent in both sexes. Regarding the me- sial location, both sexes demonstrated simi- lar percentages on the left side. However, in females, the distal location was more preva- lent compared to males. A comparable find- ing was observed in the Yemeni subpopula- tion, where the center was reported as the most frequent location [10]. Furthermore, a similar observation was noted in the Brazil- ian population [9], where the most common location was central, accounting for 42.85% and 50.98% of cases, respectively. The present study determined that the average distance from the AF to the anatomic apex of the first and second premolars in males and females was 0.61–0.62 mm (± SD 0.142, p=0.54) and 0.58–0.60 mm (± SD 0.129, p=0.22), respectively. The results of the apex-to-foramen distance measurements in this study were in close concordance with previous findings. Burch and Hulen [14] re- ported the AF distance to be 0.59 mm in a study of all tooth types, and a study con- ducted by Arora and Tewari [15] reported the distance between the AF to be in the range of 0.052–2.91 mm. A similar study conducted by Naseri et al. [16] revealed that the mean distance between AF was found to be in the range of 0.3–0.7 mm, which is con- sistent with the values calculated in the pre- sent study. In another study by Martos et al. [17], which was conducted using a stereomi- croscope on mandibular molars of a Brazil- ian population, the mean distance from the apex to the AF was 0.80 (±0.54) mm. Akhlaghi et al. [18] in an ex vivo study on a local Iranian population using India ink on mandibular second molars demonstrated that the mean (±SD) distance from the apex of the AF was 0.30–0.47 mm. India ink was used in this study, which renders the evalua- tion method distinct from that of the present study. A study conducted by Cheung et al. [19] indicated that the average distance of the AF from the anatomic apex at the C- shaped mandibular second molars in a Chi- nese population is 0.79–0.89 mm, as deter- mined using micro-CT. These minor varia- tions are, to some extent, attributable to the varying methods employed to measure the distance as well as to the different reference points that were likely utilized. Moreover, the other reason for this difference may be due to variations among diverse popula- tions. In a recent study conducted by Reda et al. in 2022, they found that one AF was the most common among all the premolars and that the mean distance of AF from the anatomic apex recorded between 3.40 ± 1.80 and 5.12 ± 1.98 [20]. A study conducted among the Chinese population by Yang et al. reported an average distance of 1–2 mm within their study sample [21]. This variation in the AF distance suggests a potential racial predilec- tion. In a recent comparable study conducted by Arsari et al, in 2021 on the anterior maxillary teeth, they observed that the mean apical foramen distance to the anatomical apex in anterior maxillary teeth in males and females was 0.64±0.36 and 0.58±0.32 mm, respectively (p=0.003). This difference was statistically significant according to their sta- tistical indices ,while the mean distance be- tween apical foramen and anatomical apex in central incisor and canine teeth was not significant in males and females (P=0.06, and p=0.25, respectively), but they observed a significant difference concerning the mean interval between apical foramen and lateral apex in lateral incisor teeth of men and women (P=0.02) [22]. In another study [23], mandibular premolars were compared and the mean length from the apical foramen to the apex was 0.59 mm and 0.47 mm, respec- tively. Meanwhile, the non-clinical and clini- cal mean lengths from the apical constriction to the apex were 0.75 mm and 0.73 mm, re- spectively. Nonetheless, no significant differ- ences were detected between the apical con- striction and the apex and apical foramen and apex [23]. Conclusions Accurate evaluation of apical anatomy using CBCT is essential for performing root canal treatment. The most common location for the apical foramina of all premolar teeth was the central AF, followed by the distal. The distance between the AF and anatomic apex in the mandibular premolars of the Kurdi- stan population was approximately 1 mm. Therefore, the extent of obturation should be 1 mm short of the radiographic apex, and the root canal procedure should be terminated at this point. Conflict of Interest The authors have no conklicts of interest to declare. Author Contribu)ons As the sole author of this manuscript, M.S. Saeed contributed to the conception, design, data collection, analysis, and interpretation of results. M.S. Saeed drafted the manuscript, ap- proved the final version, and is responsible for all aspects of the work. Funding This research received no specific grant from any funding agency in the public, Apical Foramen PosiFonal Variability and Its Minimal Distance from the Anatomical Apex in Premolars Vol 1, No 1 (2012) DOI 10.5195/d3000/2025.892 http://dentistry3000.pitt.edu 5 commercial, or private sectors. Acknowledgement We would like to give many thanks to the den- tists and technicians who gave us so much. Ethical Considerations Before commencing the study, permission was obtained from the College of Dentistry at Duhok University. The official paper num- ber was 917, dated 23/11/2021. Ap- proval was also obtained from the Ethics Committee at the Directorate General of Health in Duhok Governorate. The official pa- per number was 4255 on October 20, 2020. References 1. Vertucci FJ. Root canal anatomy of the human permanent teeth. Oral Surg Oral Med Oral Patho l984 ;99: 585–9. 2. De Pablo OV, Estevez R, Sanchezn MP, et al. Root anatomy and canal configuration of the perma- nent mandibular first molar: a systematic re- view. J Endod 2010; 36: 1919–31. 3. Chen G, Chang YC. Effects of liquid- and paste- type EDTA on smear-layer removal during ro- tary root-canal instrumentation. J Dent Sci 2011; 6: 41–7. 4. Ahmed HMA, Dummer PMH, editors. Endodon- tic Advances and Evidence-Based Clinical Guidelines. New Jersey: Wiley Blackwell; 2022. 5. Celikten B, Orhan K, Aksoy U, et al. Cone beam CT evaluation of root canal morphology of max- illary and mandibular premolars in a Turkish Cypriot population. BDJ Open 2016; 2: 15006. 6. Garg N., Textbook of Endodontics, Second Edi- tion, Jaypee Brothers, New Delhi, 2010. 7. Wolf T, Paque F, Patyna M, et al. Three dimen- sional analysis of the physiological foramen ge- ometry of maxillary and mandibular molars by means of micro-CT. Int J Oral Sci 2017; 9: 151– 7. 8. Wu MK, Wesselink PR, Walton RE. Apical termi- nus location of root canal treatment proce- dures. Oral Surg Oral Med Oral Pathol Oral Ra- diol Endod 2000; 89: 99–103. 9. Estrela C, Couto GS, Bueno MR, et al. Apical fo- ramen position in relation to proximal root sur- faces of human permanent teeth determined by using a new cone-beam computed tomographic software. J Endod 2018; 44: 1741–8. 10. Senan EM, Alhadainy HA, Genaid TM, et al. Root form and canal morphology of maxillary first premolars of a Yemeni population. BMC Oral Health 2018; 18: 94. 11. Alenezi DJ, Al Nazhan SA, Al Maflehi N, et al. Root and canal morphology of mandibular pre- molar teeth in a Kuwaiti subpopulation: a CBCT clinical study. J Int Soc Prev Comm Dent 2020; 10; 235–41. 12. Hajihassani N, Roohi N, Madadi K, et al. Evalua- tion of root canal morphology of mandibular first and second premolars using cone beam computed tomography in a defined group of dental patients in Iran. Scientifica (Cairo) 2017; 2017: 1504341. 13. Jain A, Bahuguna R. Root canal morphology of mandibular first premolar in a Gujarati popula- tion - an in vitro study. Dent Res J 2011; 8; 118– 22. 14. Burch JG, Hulen S. The relationship of the apical foramen to the anatomic apex of the tooth root. Oral Surg Oral Med Oral Pathol 1972; 34: 262– 8. 15. Arora S, Tewari S. The morphology of the apical foramen in posterior teeth in a North Indian population. Int Endod J 2009; 42: 930–9. 16. Naseri M, Ahangari Z, Momayyez M. Evaluation of the distance of apical constriction and radio- graphic apices in extracted maxillary second premolars using the clearing technique. J Dent Sch 2012; 30: 95–100. 17. Martos J, Ferrer Luque CM, González Rodríguez MP, et al. Topographical evaluation of the major apical foramen in permanent human teeth. Int Endod J 2009; 42: 329–34. 18. Akhlaghi NM, Abbas FM, Mohammadi M, et al. Radicular anatomy of permanent mandibular second molars in an Iranian population: a pre- liminary study. Dent Res J (Isfahan) 2016; 13: 362–6. 19. Cheung GS, Yang J, Fan B. Morphometric study of the apical anatomy of C shaped root canal systems in mandibular- second molars. Int En- dod J 2007; 40: 239–46. 20. Reda R, Zanza A, Bhandi S, et al. Surgical-ana- tomical evaluation of mandibular premolars by CBCT among the Italian population. Dent Med Probl 2022; 59: 209–16. 21. Yang H, Tian C, Li G, et al. A cone-beam com- puted tomography study of the root canal mor- phology of mandibular first premolars and the location of root canal orifices and apical foram- ina in a Chinese subpopulation. J Endod 2013; 39: 435–8. 22. Arsari F, Abesi F, Gholinia H,Soleymani A. Eval- uation of apical foramen position and distance from the anatomical apex of roots in anterior maxillary teeth by cone -beam computed to- mography (CBCT) in a selected Iranian popula- tion. Caspian J Dent Res 2021; 10: 20 – 9. 23. Nurulaqmar Iwani S, Kamaruzaman M, Jawami AA. Microcomputed tomography (micro-CT) analysis of apical mandibular premolar in rela- tion to clinical sign presentation: An in vitro study. Saudi Dent J. 2024 Jan;36(1):129-133. Apical Foramen PosiFonal Variability and Its Minimal Distance from the Anatomical Apex in Premolars Vol 1, No 1 (2012) DOI 10.5195/d3000/2025.892 http://dentistry3000.pitt.edu 6 Table 2. Prevalence of AF locations in mandibular premolar teeth for both genders. Tooth Type Location Male No. (%) Female No. (%) Total No. (%) Right LFPT Central 50 (58.1) 46 (53.5) 96 (55.8) Distal 26 (30.2) 20 (23.3) 46 (26.6) Mesial 10 (11.6) 20 (23.3) 30 (17.6) Total 86 (100) 86 (100) 172 (100) Right LSPT Central 52 (65) 58 (58) 110 (61.5) Distal 12 (15) 16 (16) 28 (15.5) Mesial 16 (20) 26 (26) 42 (23) Total 80 (100) 100 (100) 180 (100) Left LFPT Central 40 (48.8) 64 (72.7) 104 (60.7) Distal 24 (29.3) 16 (18.2) 40 (23.7) Mesial 18 (22.0) 8 (9.1) 26 (15.6) Total 82 (100) 88 (100) 170 (100) Left LSPT Central 56 (75.7) 66 (68.8) 122 (72.3) Distal 12 (16.2) 22 (22.9) 34 (19.5) Mesial 6 (8.1) 8 (8.3) 14 (8.2) Total 74 (100) 96 (100) 170 (100)