Root and Root Canal Morphology of Maxillary First Premolars: A Literature Review and Clinical Considerations

Morphology of Roots and Canals of Maxillary First Premolars: A CBCT Study in a Peruvian Sample

Introduction: It is important to take into account variations in structures related to dental pulp for planning the most adequate endodontic treatment management. The objective of this study was to determine the morphology of roots and canals of maxillary first premolars (MFPs) using cone-beam computed tomography (CBCT). Materials and Methods: This retrospective study included a sample of 392 CBCTs of Peruvian adults proportionally selected by sex, age, and quadrant. One MFP per individual was selected for evaluation by a calibrated evaluator based on the number of roots and canal configuration according to the Vertucci classification (VC; Cohen's κ ≥ 0.834). Pearson's χ 2 and Kruskal-Wallis tests were used with a significance level of P < 0.05. Results: Most MFP presented double roots (59.9%) and were VC type IV (52%). Morphology showed a nonsignificant difference by quadrants (P=0.994). A significant positive association was found between the presence of double roots and type IV in men and with older age, while single roots and type I and II were associated with women and younger age (P < 0.05). Double roots were associated with VC type IV (86%) and single roots with types III (34%), II (32%), and I (26%; P < 0.001). Conclusions: MFPs in a Peruvian sample presented a higher frequency of double roots with two separate canals. The morphology of root and canals was associated with age and sex.

Comprehensive analysis of root canal morphology in maxillary premolars among the Pakistani subpopulation: a CBCT-based study

BACKGROUND

Understanding the root canal morphology is essential for the success of root canal treatment. Therefore, this study aimed to evaluate and analyze the root canal configuration of maxillary premolars using Cone Beam Computed Tomography in the Pakistani subpopulation.

METHOD

This cross-sectional study utilized CBCT scans from two distinct centres: Aga Khan University in Karachi and Jinnah MRI and Body Scans in Lahore. The CBCT images were visualized using GALAXIS version 1.9 (SICAT GmbH and Co. KG, Bonn, Germany), integrated within the Sirona Dental System (D-64625 Bensheim, Germany). The scanning parameters were standardized at 85 kV, 7 mA, with a 15-s exposure time and a voxel size of 0.16 mm. A total of 707 CBCT scans were collected, encompassing 2180 maxillary premolars. Root canal configurations were classified based on (Ahmed et al. Int Endod J. 2017;50(8):761-70). Statistical analyses were performed using SPSS version 26, employing the Chi-square test with a significance level set at p < 0.05.

RESULTS

The distribution of root canal morphologies varied significantly with age and gender. Among maxillary premolars, 50% exhibited the typical configuration of 2MPMB1 L1 (two roots, single canal in each buccal and lingual root), while 26% of maxillary right second premolars displayed 1MPM1 (one root, one canal). Overall, 1MPM1 accounted for 27.4% of the total cases in the second premolars. There was no statistically significant relationship between age and root canal distribution in either first premolars (p = 0.338) or second premolars (p = 0.833). Regarding gender, a significant difference was observed in the distribution of right maxillary 1st premolars (p = 0.022*), with a higher prevalence among females.

CONCLUSION

This study offers significant insights into the anatomical variations of root canals in maxillary premolars across diverse regional subpopulations in Pakistan. While specific root canal configurations were prevalent, the findings indicate no statistically significant correlation between age and root canal morphology in maxillary premolars. However, a notable gender disparity was observed in the distribution of the right maxillary first premolars.

Prevalence and Classification of C-Shaped Canal and Radix in Mandibular Molars Using Cone-Beam Computed Tomography on Mexican Population

The diverse morphological configurations in teeth present clinical challenges in root canal treatment, complicating instrumentation and irrigation processes, which can lead to treatment failure. Understanding anatomical variations, such as C-shaped canals and radix entomolaris, enhances clinical skills and improves long-term endodontic treatment success rates. Cone-beam computed tomography (CBCT) offers superior diagnostic capabilities over conventional radiography, enabling the pre-operative detection of root configurations and canal numbers, facilitating personalized endodontic treatments. A total of 2173 teeth of a Mexican population, including 1057 first mandibular molars and 1116 s mandibular molars, were studied using only CBCT to identify C-shaped canals and radix configurations of patients who were treated from 2018 to 2023 at the Department of Radiology at the Faculty of Dentistry, Juarez University of the State of Durango, Mexico. C-shaped canals were identified in 160 teeth, with a prevalence of 0.2% in first mandibular molars and 14.1% in second mandibular molars. The highest frequency was in the left second mandibular molar (3.7) at 14.8%. Gender differences were significant, with higher prevalence in females (27.3%) compared to males (13.3%). The most common C-shaped canal configuration was type C2 (39.3%). Radix entomolaris was found in 52 teeth, with a prevalence of 3.4% in first mandibular molars and 1.4% in second mandibular molars. This research on a Mexican population using cone-beam computed tomography (CBCT) highlights significant findings in the prevalence and types of C-shaped canals and radix entomolaris in mandibular molars for this population. The left second mandibular molar (3.7) showed the highest prevalence at 14.8%, followed closely by the right second mandibular molar (4.7) at 13.5%, with a significant difference (p < 0.001). We found a significant difference in the prevalence of C-shaped canals between genders (p = 0.004, OR 1.78). Additionally, radix entomolaris (p < 0.001) was more frequently identified in first mandibular molars to a significant degree. These insights underscore the importance of CBCT in diagnosing complex root anatomies, which can greatly enhance the success rates of endodontic procedures by allowing for more tailored and precise treatments for this population.

Exploring age and gender variations in root canal morphology of maxillary premolars in Saudi sub population: a cross-sectional CBCT study

BACKGROUND

In complex teeth like maxillary premolars, endodontic treatment success depends on a complete comprehension of root canal anatomy. The research on mandibular premolars' root canal anatomy has been extensive and well-documented in existing literature. However, there appears to be a notable gap in available data concerning the root canal anatomy of maxillary premolars. This study aimed to explore the root canal morphology of maxillary premolars using cone-beam computed tomography (CBCT) imaging, considering age and gender variations.

METHODS

From 500 patient CBCT scans, 787 maxillary premolar teeth were evaluated. The sample was divided by gender and age (10-20, 21-30, 31-40, 41-50, 51-60, and 61 years and older). Ahmed et al. classification system was used to record root canal morphology.

RESULTS

The most frequent classifications for right maxillary 1st premolars were 2MPM1 B1 L1 (39.03%) and 1MPM1 (2.81%), while the most frequent classifications for right maxillary 2nd premolars were 2MPM1 B1 L1 (39.08%) and 1MPM1 (17.85%). Most of the premolars typically had two roots (left maxillary first premolars: 81.5%, left maxillary second premolars: 82.7%, right maxillary first premolars: 74.4%, right maxillary second premolars: 75.7%). Left and right maxillary 1st premolars for classes 1MPM1 and 1MPM1-2-1 showed significant gender differences. For classifications 1MPM1 and 1MPM1-2-1, age-related changes were seen in the left and right maxillary first premolars.

CONCLUSION

This study provides novel insights into the root canal anatomy of maxillary premolars within the Saudi population, addressing a notable gap in the literature specific to this demographic. Through CBCT imaging and analysis of large sample sizes, the complex and diverse nature of root canal morphology in these teeth among Saudi individuals is elucidated. The findings underscore the importance of CBCT imaging in precise treatment planning and decision-making tailored to the Saudi population. Consideration of age and gender-related variations further enhances understanding and aids in personalized endodontic interventions within this demographic.

Challenges Faced in Treating Maxillary Second Premolars With Three Canals: A Case Report

The maxillary second premolar has long been regarded as a tooth with a straight root canal anatomy, typically featuring a single root with two canals. However, emerging evidence suggests this tooth may harbor a more intricate internal morphology, challenging conventional perceptions, and treatment approaches. One such variation is three root canals within the upper second premolar, which has been gaining increasing attention in endodontic literature. Root canal treatment of maxillary second premolars with three canals demands meticulous debridement, shaping, and disinfection. A combination of magnification, illumination, and appropriate instrumentation aids in locating, negotiating, and cleaning the accessory canals effectively. Thorough cleaning of accessory canals can be achieved through effective irrigation solutions such as sodium hypochlorite, ethylenediaminetetraacetic (EDTA), and chlorhexidine, which help dissolve organic tissues and remove debris. Techniques like ultrasonic and sonic activation, as well as negative pressure irrigation systems, enhance the penetration and effectiveness of these irrigants. Additionally, the use of modern nickel-titanium rotary files, ultrasonic irrigation, and supplementary chelating agents enhances the management of complex canal configurations.

Shape variation in modern human upper premolars

Morphological variation in modern human dentition is still an open field of study. The understanding of dental shape and metrics is relevant for the advancement of human biology and evolution and is thus of interest in the fields of dental anthropology, as well as human anatomy and medicine. Of concern is also the variation of the inner aspects of the crown which can be investigated using the tools and methods of virtual anthropology. In this study, we explored inter- and intra-population morphometric variation of modern humans' upper third and fourth premolars (P3s and P4s, respectively) considering both the inner and outer aspects of the crown, and discrete traits. We worked by means of geometric morphometrics on 3D image data from a geographically balanced sample of human populations from five continents, to analyse the shape of the dentinal crown, and the crown outline in 78 P3s and 76 P4s from 85 individuals. For the study of dental traits, we referred to the Arizona State University Dental Anthropology System integrated with more recent classification systems. The 3D shape variation of upper premolar crowns varied between short and mesio-distally broad, and tall and mesio-distally narrow. The observed shape variation was independent from the geographical origin of the populations, and resulted in extensive overlap. We noted a high pairwise correlation (r1 = 0.83) between upper P3s and P4s. We did not find any significant geographic differences in the analysed non-metric traits. Our outcomes thus suggest that geographical provenance does not play a determinant role in the shaping of the dental crown, whose genesis is under strict genetic control.

Comparative Morphology of the Carnassial Teeth Root Canals in Mixed-Breed Dogs and German Shepherds

Root canal treatment of carnassial teeth in dogs is a common endodontic technique which aims to re-establish or maintain the health of the periapical tissues. In total, 43 dogs were used in this study. Root canal morphology was evaluated in 86 superior fourth premolars and 86 inferior first molars. Apical delta was present in 247 roots, while obliteration of the root canal was found in 11 roots. The most common type of apical delta of the roots of superior fourth premolars was type II, with up to 10 apical ramifications, while type IIIA, with 10-20 apical ramifications, was most commonly present in the roots of inferior first molars. Considering that knowledge of the morphology of root canals is essential for a successful endodontic procedure, the aim of this study was to analyze and compare the morphology of root canals in the carnassial teeth of German shepherds and mixed-breed dogs. Apical resection for the purpose of endodontic therapy of the superior fourth premolar and the inferior first molar is indicated at a length of 4 to 6 mm from the anatomical tip of the roots, which would completely remove the apical delta of these two teeth.

CBCT Evaluation of Root Canal Morphology of Maxillary First Premolar in Saudi Subpopulation

Background and Objective

Clinicians must possess a comprehensive understanding of variations in canal morphology and configuration during endodontic procedures to enhance treatment success. This study aims to assess and analyze the canal configurations of maxillary first premolars using Cone-Beam Computed Tomography within the sub-population of Western Saudi Arabia.

Materials and Methods

In this cross-sectional study, following the acquisition of ethical clearance from Batterjee Medical College in Jeddah, Saudi Arabia, a retrospective examination of Cone-Beam Computed Tomography (CBCT) scans of maxillary first premolars in adult patients was conducted. The study focused on quantifying the number of canals and characterizing their configurations, with classification based on Vertucci's categorization.

Results

The study examined 399 CBCT images of maxillary first premolars, revealing that type IV canal configurations were the predominant morphology (56.9%), followed by type V (24.6%). Significant gender-related disparities were observed, with females displaying a higher incidence of types I and V canals. At the same time, males exhibited a greater prevalence of types IV and VI canals. Notably, no substantial associations were discerned between canal types and age groups.

Conclusion

Within the context of maxillary first premolars, type IV canal configuration emerged as the most prevalent. Gender-based distinctions were evident, with females predominantly presenting types I and V canal configurations, whereas males displayed a higher occurrence of types IV and VI canal configurations.

The Effect of Calcium Hydroxide, Triple Antibiotic Paste and Chlorhexidine on Pain in Teeth with Symptomatic Apical Periodontitis: A Randomised Controlled Trial

BACKGROUND

One of the main reasons for post endodontic pain is the polymicrobial intracanal flora that may survive the initial disinfection. A single antimicrobial agent might not provide adequate disinfection, and an antimicrobial combination such as triple antibiotic paste was tested to achieve this goal.

AIM

The study aimed to assess the efficacy of three intra-canal medicaments on post root canal preparation pain.

MATERIALS AND METHODS

Eighty patients with single-rooted necrotic teeth and symptomatic apical periodontitis were randomly assigned to four treatment groups (n = 20). Their preoperative pain was recorded on Wong-Baker's FACES pain rating scale. After chemo-mechanical canal preparation, intracanal medications were applied to the groups (Group 1 (20% calcium hydroxide), Group 2 (2% chlorhexidine), Group 3 (tri-antibiotic paste), Group 4 (no medication (Control group)). Patients were instructed to record pain on the Wong-Baker FACES pain rating scale at 4, 48, 72 and 96 hrs, postoperatively. Pain scores were analyzed using a one-way ANOVA test and Tukey's post hoc test and, if significant, Dunn's test was used for pair-wise comparisons. The significance level was set at a p-value ≤ 0.05.

RESULTS

Tukey's post hoc test revealed significantly lower pain scores in Group 3 compared with other groups at all follow up intervals. Dunnett's test showed significantly lower pain in Group 3 compared with the Control group at 48, 72 and 96 hrs, postoperatively.

CONCLUSIONS

Triple-antibiotic paste showed effective pain control as an intracanal medication on necrotic teeth with symptomatic apical periodontitis.

Maxillary Premolars with Four Canals: Case Series

The aim of this case series is to contribute to the better knowledge and management of the complex anatomical configurations of maxillary premolars with four canals. The paper explains the endodontic treatment of five maxillary premolars with four canals, with three buccal and one palatal orifices, in different patients. The cases report several approaches in the treatment of four-canal maxillary premolars including a conservative canal preparation with a hybrid shaping technique, endodontic microsurgery and the application of biomaterials. The use of an operating dental microscope, different operating strategies and the critical evaluation of radiographs are all necessary steps for the correct and safe endodontic management of these teeth.

Evaluation of Variations in Root Canal Anatomy and Morphology of Permanent Maxillary Premolars among the Emirate Population using CBCT

Background:

Many types of research have revealed that root canal anatomy differs by race and country based on various national populations, but no study has been conducted on the UAE population.

Objectives:

Identifying the most common morphology of the upper premolars in a group of local and non-local people in the UAE.

Methods:

Cone-beam computed tomography (CBCT) images of 215 intact maxillary premolars were analyzed. The Pearson Chi-squared test and the two samples t-test were applied.

Results:

Most of the maxillary first premolars were two-root formed (90%). Single-rooted teeth were less common (8%). Three-rooted maxillary first premolars represented a low frequency of 1.9%. Most of the maxillary second premolar teeth studied in this research (52%) had two roots. Almost all local and non-local populations had two canals for both first and second maxillary premolar. Only two maxillary first premolars (0.2%) had the three-canal morphology. The most frequent canal morphology in the maxillary first premolar group among local UAE and non-local was type V. The maxillary second premolar group among local UAE was type II (32%). In non-local UAE, type V (25%). In addition, six types of uncommon canal anatomic variants (types 1-2-3, 2-3-2, 3-2-1, 1-2-3-2, 2-1-2-1, and 3-2) were discovered in 3.7% of local UAE and 36.3% of non-local UAE.

Conclusion:

The results suggest a more quantitative approach to maxillary first and second premolar access cavity preparation in the UAE population to prevent errors and iatrogenic damage when identifying the canals.

Evaluation of Root Canal Configuration of Maxillary and Mandibular First Molar by CBCT: A Retrospective Cross-Sectional Study

Adequate knowledge of root canal morphology along with its probable variations is imperative to acquire successful endodontic treatment. This retrospective cross-sectional study aimed to investigate the root canal configuration of maxillary and mandibular first molar using Cone-Beam Computed Tomography (CBCT) among patients in Al-Ahsa region, Saudi Arabia. A total of 377 samples were included, out of which 123 CBCT (I-CAT Vision QTM) scans with intact all first permanent molars were selected in this study and scanned in sagittal, axial, and coronal views by using BlueSkyPlan software. The number of canals in each root and their configuration according to the Vertucci classification system was evaluated. Statistical analysis was analyzed using SPSS version 21 (IBM). Chi-square test was applied to evaluate the association of root canal morphology and mandibular and maxillary first molars with respect to gender. Out of 123 CBCT scans, 59 (48.0%) were males and 64 (52.0%) were females; the mean age was 26.95 ± 10.65 years. The mesiobuccal root of bilateral maxillary first molar had Type-I (87.0%) of Vertucci classification followed by Type-IV (9.8%). Additionally, all mesiobuccal roots (100%) of the left mandibular first molar had Type-I of Vertucci’s classification. A significant association has been observed between gender and a number of canals in bilateral maxillary first molars. Females showed a significantly higher prevalence of three-root canal configuration in maxillary first molars of both sides compared four canals found most commonly in males (p = 0.004). This study concluded that the majority of maxillary and mandibular permanent first molars had three roots and three canals with Type-I Vertucci’s classification in patients belonging to the Al-Ahsa region of the Saudi Arabia. It was also proved that gender is significantly associated with the number of canals in a bilateral maxillary molar.

Effects of root canal enlargement on unprepared areas and coronal dentine thickness of three-rooted maxillary first premolars with different root configurations: a stepwise micro-CT study

AIM

To evaluate the effects of progressive root canal enlargements on the unprepared surface area and remaining dentine thickness of three-rooted maxillary first premolars with different root configurations.

METHODOLOGY

Thirty three-rooted maxillary first premolars with 3 root configurations (n=10) were selected and scanned in a micro-CT device. The root canals were sequentially enlarged with rotary instruments sizes 30.02 (step 1), 30.04 (step 2), and 30.06 (step 3). After each step, a new scan was taken. Analysed parameters included morphometric measurements (length, volume and surface area), number of static voxels, and minimal dentine thickness. Statistic analyses were performed with one-way ANOVA post hoc Tukey tests and paired sample t-test at a significance level of 5%.

RESULTS

No statistical differences were observed among groups regarding the morphometric parameters and static voxels (p > 0.05). The minimal dentine thickness of the distobuccal root significantly changed depending on the root configuration (p < 0.05), while no differences were observed in the other roots (p > 0.05). A great variation in the position of the minimal dentine thickness was observed after preparation. Overall, mean percentage reduction of dentine thickness was higher in the buccal roots than in the palatal root (p < 0.05). In the mesiobuccal and distobuccal root, the number of slices with minimal dentine thickness lower than 0.05 mm increases 2 to 3 times and 3 to 4 times, respectively, from steps 1 to 3.

CONCLUSIONS

Instruments sizes 30.02 and 30.04 can be safely and effectively used to enlarge the buccal and palatal canals of three-rooted maxillary first premolars.

Three-dimensional evaluation of root canal morphology of maxillary first premolars: Micro–computed tomographic study

Aim

The aim of this in vitro study was to investigate the root and root canal morphology of maxillary first premolar teeth in a Kuwaiti population using micro–computed tomography (μ- CT).

Materials and methods

A total of 100 maxillary first premolars were scanned in a micro– computed tomographic device. The external anatomy (number of roots, distance from cementoenamel junction to apex, and presence of a palatal groove) and internal anatomy (number of canals and presence of apical deltas, lateral canals, and isthmi) of teeth were analyzed using descriptive analysis.

Results

The number of roots was one root (57 %), two roots (41 %), and three roots (2 %). The longest and shortest roots measured 17.7 and 11.2 mm, respectively. The palatal groove was present in 63.4 % of the teeth. According to Vertucci’s classification, type IV configuration was the most prevalent (53 %), followed by type II. A new root canal configuration type (1–2–1–2–1) was detected. Apical deltas, lateral canals, and isthmi were present in 33 %, 48 %, and 21 % of teeth, respectively.

Conclusion

Type IV canal configuration was the most common root canal configuration. A new root canal configuration type IX for (1–2–1–2–1) was proposed for Kuwaiti population. The μ-CT device could to be a better diagnostic tool for understanding the anatomy of the root canal system.

Cone-beam computed tomography three-dimensional reconstruction aids treatment of three root canals with severe curvature in maxillary first premolar: a case report

The maxillary first premolar commonly has one or two root canals; the presence of three canals is rare. These root canals are easily missed during treatment, resulting in failure of root canal therapy. The present report describes a case in which three root canals in the maxillary first premolar were diagnosed by cone-beam computed tomography. The herein-described patient was successfully treated using three-dimensional reconstruction technology to determine the form and direction of curvature of the root canals.

A Cone-Beam Computed Tomography (CBCT) Study of Root Anatomy, Canal Morphology and Bilateral Symmetry of Permanent Maxillary Premolar Teeth Among the Qatari Subpopulation

Objectives:

The study aims to evaluate the root anatomy, canal morphology, and symmetry of maxillary premolars teeth in a Qatari subpopulation using cone-beam computed tomography (CBCT).

Materials and Methods:

544 CBCT images of Qatari patients were analyzed by two endodontists. Tooth position, number of roots, canal configuration, and number of canals per root were investigated. A chi-square test was used to evaluate the association between gender and the number of roots. The interexaminer and intraexaminer were performed and documented.

Results:

The most common root anatomy and canal morphology observed in maxillary first premolars (MFP) were two roots (70.6%) with a single canal per root, while in maxillary second premolars (MSP), there was one root (84.3%) with a single canal (83%).

Type I Vertucci morphology was predominated in all roots of two-rooted MFP (97%), three-rooted MFP (100%), single-rooted MSP (42%), and two-rooted MSP (100%). The Chi-square test showed an association between gender and number of roots in both MFP and MSP, with a higher number of roots seen in men(P<0.05).

A symmetrical pattern was observed in the number of roots and canals in both maxillary premolars. But the symmetry for the type of canal configuration is higher in MFP (78%) than MSP (54%).

Conclusion:

In the Qatari subpopulation, most MFP had two roots with a predominance of type I Vertucci, while MSP had one root with type I. Contralateral MSP showed more diversity in canal configuration that should be considered during root canal treatment. CBCT is an effective diagnostic tool to investigate root anatomy and canal morphology.

Visual inspection of root patterns and radiographic estimation of its canal configurations by confirmation using sectioning method. An ex vivo study on maxillary first premolar teeth

Background

A thorough understanding of the original root and canal anatomy is a critical technical prerequisite for performing cleaning and shaping treatments. Therefore, this research aimed to characterize maxillary first premolar teeth' root morphology and canal architecture.

Methods

One hundred forty-two extracted human adult maxillary first premolar teeth have been retrieved. The extracted teeth were thoroughly cleaned and irrigated to eliminate any remaining debris or blood. They were then preserved in formalin solution until they were eligible for screening. To begin, a visual examination was employed to ascertain the number of roots and their geometry in each sample. Then, utilizing digital radiography in two plains, mesiodistal and distomesial, to further determine those parameters. Finally, a sectioning technique had been used to have the samples cut mesiodistally into slices to validate the internal root canal architecture and identify the number of root canals and their varieties in accordance with Vertucci's categorization system. The canal layout, the pulp chamber, and the root canals were all highlighted (marked) using a fine tip marker in a permanent orange hue to make the canal features more accessible and accurate to visualize. All of the processes were conducted by two highly qualified dentists. The sample size was estimated statistically using the Sealed Envelope program, and the percentage of each configuration was derived in proportion to the overall sample size in order to establish the percentage of each type in each configuration.

Results

From the 142 teeth examined, 42 (29.57%) had one root, 97 (68.31%) had two roots, and only three premolars (2.12%) had three roots. Concerning canal configurations, 100 teeth (70.43%) had type (IV) canal configuration, followed by 37 teeth (26.05%) had types (V), three teeth (2.12%) had type (VIII), and one tooth (0.70%) for each of type (I) and type (II).

Conclusions

The anatomical pattern of inspected maxillary first premolars are mainly two rooted and predominantly have a type (IV) canal morphology.

Anatomical Evaluation of Root and Root Canal Configuration of Permanent Maxillary Dentition in the Population of the Kingdom of Saudi Arabia

AIM

This study is aimed at combining the sample sizes of all studies on permanent maxillary teeth conducted in different regions of the Kingdom of Saudi Arabia (KSA) to obtain a large sample size that represents the population of the KSA. The outcome of these combined studies is compared with international studies in terms of the number of roots, number of canals, and canal configurations on the basis of Vertucci's classification. Methodology. The studies were systematically reviewed using the Preferred Reporting Items for Systematic Review and Meta-analysis chart. Studies were included in the analysis if they were conducted in the KSA, involved permanent human maxillary teeth, and had a sample of more than 10 teeth (power). By contrast, studies were excluded if they involved deciduous teeth in the sample size, investigated nonhuman teeth, were not conducted in the KSA, and were case reports, case series, review studies, and anomalies. Relevant literature was searched from PubMed, Scopus, Web of Science, Embase, Cochrane, and Direct Science by two calibrated teams, starting in August 2020, without time limits or language restrictions.

RESULTS

The database searches and cross-referencing identified a total of 19 relevant studies. All maxillary canines (N = 1,018) had one root, whereas 98.4% had one canal and 98.3% had Vertucci type I. Moreover, 63.2% of the maxillary first premolars had two roots, and 91.4% had two canals. The most common Vertucci root canal configuration was type IV (64.6%). The maxillary second premolars mostly had one root (84.4%) and one canal (50.4%). The most common canal configuration was Vertucci type I (47.1%). The majority of maxillary first molars had three roots (98.9%), 48.7% of which had three canals, and 46.4% had four canals. The most prevalent feature of the canal morphology of mesiobuccal roots was Vertucci type II (35.3%). The investigated maxillary second molars had three roots, 88.0% of which had three canals.

CONCLUSION

This systematic review represents the Saudi population since samples were combined from different studies from different regions of the country. Variations in findings were observed in the same group of teeth from different regions and the same region, while the overall combined samples results fell within the range of other international studies.

Residual Dentin Thickness in Bifurcated Maxillary Premolars after Cervical Preflaring Preparation: A CBCT Analysis

Objective:

This study evaluated the residual dentin thickness (RDT) of maxillary premolars after the use of different cervical preflaring (PF) drills by using cone-beam computed tomography (CBCT).

Methods:

Eighty bifurcated maxillary premolars were accessed and randomly divided into 5 groups (n=16). PF was performed with Gates-Glidden #1, #2, and #3 (group 1), Largo #1 and #2 (group 2), and LA Axxess #20/.06 (group 3), #35/.06 (group 4), and #45/.06 (group 5). CBCT images were acquired before (preoperative) and after (postoperative) PF. Initial and final cervical dentin thickness was measured at the buccal, palatal, mesial, and distal aspects, 0.5 mm coronally to the furcation, on both buccal and palatal roots, using CBCT’s image analysis software. The percentage of removed dentin after PF preparation was also calculated. Data were analyzed using ANOVA followed by Tukey’s test at a significance level of P < 0.05.

Results:

No statistically significant differences were found among the groups for preoperative or postoperative RDT (P > 0.05). LA Axxess #20/.06 (group 3) removed significantly less cervical dentin at all root canal aspects on both buccal and palatal roots. The mesial aspect of the buccal root and distal aspect of the palatal root were significantly reduced after the use of LA Axxess #45/.06 (group 5) and Largo #1 and #2 drills (group 2), respectively (P < 0.05).

Conclusion:

PF in bifurcated maxillary premolars should be performed with LA Axxess instrument #20/.06. The use of Gates-Glidden #1, #2, and #3, Largo #1 and #2, and LA Axxess #45/.06 drills should be done with caution.

Evaluation of Palatal Furcation Groove and Root Canal Anatomy of Maxillary First Premolar: A CBCT and Micro-CT Study

Objectives

This study is aimed at investigating the root and root canal morphology by cone beam computed tomography (CBCT) and palatal furcation groove of the buccal root by microcomputed tomography (micro-CT) of maxillary first premolars in a Chinese subpopulation.

Methods

This study assessed CBCT images of 440 patients aged 14-80 years. Based on Vertucci's classification, the number of roots and the canal configuration were determined. Forty-eight maxillary first premolars with furcation grooves were analyzed by micro-CT in patients aged 18-25 years.

Results

Based on the CBCT assay, 70.22% and 29.32% of maxillary first premolars were 1 root and 2 roots, respectively. The configuration indicated statistical difference (P < 0.05) between male and female patients. The most common canal type was type IV and was found in 44.32% of cases, followed by type I in 27.84%, and then type II in 20.57%. Root bifurcations had 40.13% prevalence which was distributed more in the middle third than in the cervical and the apical third. For the micro-CT study, 95.83% of the furcation groove configuration was found in the bifurcated maxillary first premolars. The length varied from 1.02 to 7.63 mm. The mean depth of this groove was 0.57 mm in the root coronal, 0.47 mm in the root middle, and 0.22 mm in the root apical level. Palatal dentin width was smaller than 1 mm.

Conclusion

The anatomy of the root and root canal system and the irregular wall width of maxillary first premolars with furcation grooves may help dentists to understand the anatomical morphology and improve the outcomes of endodontic treatment.

Root Form and Morphology of Human Permanent Maxillary First Premolars of an Indo-Dravidian Population Based in Southern India: An In Vitro Study

Aim:

The aim of this study was to analyze root form and morphology of human maxillary first permanent premolars of an Indo-Dravidian population from southern India.

Materials and Methods:

Eight hundred and twenty-two maxillary first permanent premolars were cleansed and stored appropriately. Morphology and root form analysed, segregated into Groups (Gps): Gp I, Gp II, and Gp III, and later divided into subgroups (SGs) based on specific criteria. Gp I was divided into two SGs: SG A (minimal or absence of grooving in the root) (n = 252) and SG B (clear and defined longitudinal groove in the root) (n = 104), and Gp II was divided into SG C (roots dividing in coronal one-third) (n = 154), SG D (roots dividing in the middle one-third) (n = 158), and SG E (roots dividing in the apical one third) (n = 138). Gp III consisted of only one SG F (teeth with three roots) (n = 16). The groups were analyzed separately, their external root form and morphology were recorded. Root form was analyzed, and results were tabulated. This study was compared with other studies and statistically analyzed.

Results:

Gp II was common with an incidence of 54.74%. Gp I was the next most common with an incidence of 43.3%. Gp III was the least common with an incidence of 1.94%. The number and distribution of roots was also computed. Six types of root form were identified (Type [Ty] A = 30.65%, Ty B = 12.65%, Ty C = 18.73%, Ty D = 19.22%, Ty E = 16.78%, and Ty F = 1.94%).

Conclusion:

Awareness and assessment of root form, number preoperatively with regard to specific populations before initiation will pave way for successful outcome of therapy.

Root canal morphology of maxillary and mandibular first premolars analyzed using cone-beam computed tomography in a Shandong Chinese population

The aim of this study was to explore the root morphology and root canal configuration of first premolars among Shandong Chinese residents using cone-beam computed tomography (CBCT).Randomly selected CBCT images were collected from 648 patients (44% women, 56% men). In total, 1268 maxillary and 1296 mandibular first premolars were analyzed. The number of roots and the canal configuration were recorded and identified based on Vertucci's classification.The majority of the maxillary first premolars had 1 root (67.4%), followed by 2 roots (32%). A 2-canal configuration (89%) was the most prevalent observation. For mandibular first premolars, 98.8% had 1 root and 81% presented the type I configuration. There were no statistical differences in the number of roots or morphology in terms of the left/right side or sex (P > .05).Among Chinese residents, the majority of maxillary first premolars had 1 root and 2 canals, whereas the most common anatomical configuration for mandibular first premolars was 1 root with 1 canal.

An Ex Vivo Study of Root Canal System Configuration and Morphology of 115 Maxillary First Premolars

INTRODUCTION

The aim of this study was to investigate the root canal system morphology of maxillary first premolars by means of micro-computed tomographic imaging in a Swiss-German population.

METHODS

The root canal configuration (RCC) of 115 maxillary first premolars (Mx1Ps) were investigated by means of micro-computed tomographic imaging and 3-dimensional imaging. The RCC and the physiological foramina results are described by a 4-digit system code.

RESULTS

Twelve different RCCs were observed in 30 single-rooted Mx1Ps; 2-2-2/2 (30.0%), 1-2-2/2 (13.3%), 1-2-1/2 (10%), and 2-2-1/2 (10.0%) were the most frequent ones. Seven different RCCs were observed in 2-rooted Mx1Ps (n = 81) in which the 1-1-1/1 (56.8%), 1-1-1/2 (29.6%), and 1-1-2/2 (8.6%) in the buccal root and 1-1-1/1 (92.6%) and 1-1-1/2 (6.2%) in the palatal root RCCs appeared most frequently. Three-rooted Mx1Ps (n = 4) showed a 1-1-1/1 (100.0%) RCC in all roots. The buccal root canal in 2-rooted Mx1Ps had 1 physiological foramen in 59.3% and 2 in 40.7% and 1 to 6 accessory foramina in 38.2%. The palatal root canal showed 1 physiological foramen in 93.8% and 2 in 6.2% and 1 to 2 accessory foramina in 14.8%. Single-rooted Mx1Ps showed 1 physiological foramen in 10.0%, 2 in 70.0%, 3 in 13.3%, and 4 in 6.7% and 1 to 3 accessory foramina in 46.7%.

CONCLUSIONS

The results of this study provide detailed morphologic RCC information of Mx1Ps in a Swiss-German population. Single-rooted Mx1Ps showed morphologic diversifications more frequently than 2- or 3-rooted Mx1Ps. Within 2-rooted Mx1Ps, the buccal root had higher RCC variety, accessory canals, and foramina number than the palatal root.

Root canal configuration and root wall thickness of first maxillary premolars in an Israeli population. A Cone-beam computed tomography study

Anatomical features of first maxillary premolars may greatly affect endodontic and following restorative treatments. The aim of this study was to evaluate root canal configuration and root wall thickness of first maxillary premolars using a preexisting CBCT database. A CBCT database of 400 first maxillary premolar was used to study canal configuration, presence of furcation-facing groove on the buccal root and root wall thickness. Root wall thickness was measured from axial CBCT slices at three critical points of the root: The most coronal part of the furcation-facing groove in the buccal root, when present, the CEJ level of the palatal root and 5 mm apically to the CEJ level of the palatal root. Vertucci Type IV configuration was the most common among all teeth, but in single-rooted teeth, Vertucci Type II was predominant. The mean thickness of the buccal root in the area of a furcation-facing groove was 1.1 (±0.2) mm, but in 39% of the cases, it was thinner than 1 mm. The mean thickness of the palatal root at 5 mm from the CEJ was 1.1 (±0.2), but in 28% of the cases, it was thinner than 1 mm. Thickness of root dentin walls of first maxillary premolars varies and may be limited at critical points in both buccal and palatal roots. In case the patient has a previous CBCT scan it may be useful for planning treatment of first maxillary premolars, in order to recognize and avoid potential risks such as furcation-facing groove, thin dentin walls in critical areas and presence of Type II Verucci canal, all of which may dictate less invasive procedures, using smaller files.

Root Canal Anatomy of Maxillary First Premolar by Microscopic Computed Tomography in a Chinese Adolescent Subpopulation

Objectives

To investigate the root morphology and root canal anatomy of maxillary first premolar using microscopic computed tomography (micro-CT).

Methods

324 maxillary first premolars were collected and scanned. The root and canal diameter, canal wall thickness, root taper, and cross-sectional shapes were determined in the single root with 1 canal (SR1C), single root with 2 canals (SR2C), and 2 roots with 2 canals (2R2C) by micro-CT.

Results

The results showed that single-rooted maxillary premolars were more common than other types. The incidence of SR1C, SR2C, and 2R2C reached 25%, 26.39%, and 26.39%, respectively. Root and canal diameters and canal wall thickness were decreased from coronal third to apical foramen. The three parameters and canal taper showed increases from buccal and palatal (BP) to mesiodistal (MD) aspects. The root canal tapers were smallest of the middle third level. The findings showed the different variations in 2R2C teeth. The root canal cross-sectional morphology in maxillary first premolars is complicated, including round, oval, long oval, flat canal, and irregular canal shapes. The distribution varied in different aspects.

Conclusion

Root canal morphology showed a wide variation and complicated structure. The single-rooted teeth were more common in the Chinese adolescent population, and the majority of maxillary first premolars have two canals.

Surgical management of an accessory canal in a maxillary premolar: a case report

We report the surgical endodontic treatment of a maxillary first premolar with a lateral lesion that originated from an accessory canal. Although lesions originating from accessory canals frequently heal with simple conventional endodontic therapy, some lesions may need additional and different treatment. In the present case, conventional root canal retreatment led to incomplete healing with the need for further treatment (i.e., surgery). Surgical endodontic management with a fast-setting calcium silicate cement was performed on the accessory canal using a dental operating microscope. At the patient's 9-month recall visit, the lesion was resolved upon radiography.

Three-rooted maxillary first premolars incidentally detected on cone beam CT: an in vivo study

PURPOSE

To explore the incidence and analyze the morphology of three-rooted maxillary first premolars (MFPs) incidentally detected on cone beam computed tomography (CBCT) scans.

METHODS

Of 1328 patients who underwent CBCT scans of the maxilla, only patients with three-rooted MFPs were selected. Morphological features, including the lengths and diameters of palatal, mesiobuccal (MB) and distobuccal (DB) roots, the positions of bucco-palatal (B-P) bifurcations, the distances between root canal bifurcations and cementoenamel junctions (CEJs) and the distances between the apical thirds of the roots, were measured. The canal configuration and the visibility of root canals were also evaluated.

RESULTS

A total of 16/1328 (1.2%) patients had one or two three-rooted MFPs, and a total of 22/2656 (0.8%) three-rooted MFPs were enrolled. The lengths and diameters of palatal roots were significantly greater than those of other roots. The positions of B-P bifurcations were located mainly at the middle third of the root. The median distances between root canal bifurcations and CEJs were 3 mm for B-P bifurcations and 5.2 mm for MB-DB bifurcations. The distance between MB and DB roots was significantly shorter than the distances between other root pairs. All teeth had a type VIII canal configuration. Palatal roots exhibited the best visibility of root canals, whereas the worst visibility was observed within DB roots. A gender-related relationship was observed only for the lengths of the roots.

CONCLUSIONS

The occurrence of three-rooted MFPs is not unusual; therefore, preoperative CBCT evaluation could be suggested whenever endodontic procedures are planned on an MFP.

Root Canal Morphology of Maxillary First Premolars Using the Clearing Technique in a South Indian Population: An In vitro Study

Background:

The success of root canal therapy requires a good knowledge of root canal morphology. Literature review shows variations in a number of roots and canal morphology in studies done across the globe.

Aim:

The purpose of this study was to evaluate the root canal morphology in maxillary first premolars using the clearing technique in a South Indian population.

Methodology:

Two hundred and twenty-five extracted noncarious, nonfractured, sound maxillary first premolars were collected, cleaned, and were injected with India ink to stain the root canals. Teeth were then decalcified and cleared using methyl salicylate. Teeth were then viewed under a stereomicroscope to evaluate the number of roots, root canal morphology based on the Vertucci's classification, variations, and additional features such as accessory root canals, lateral canals, furcation canals, isthmus, and apical delta.

Results:

Nearly 52.88% of maxillary first premolars were single rooted, 44.88% had two roots, and 2.22% had three roots. Vertucci's Type IV root canal configuration was the most common type in maxillary first premolars and was seen in 66.51% of cases followed by Type II in 13.4%. Type I was seen in 9.76%, Type VI in 6.51%, Type VIII in 2.32%, Type III in 0.46%, Type V in 0.46%, and Type VII in 0% of teeth.

Conclusion:

The majority of the maxillary first premolars included in our study were single rooted and Vertucci's Type IV was the most common type of root canal configuration.

Symmetry of root anatomy and root canal morphology in maxillary premolars analyzed using cone-beam computed tomography

OBJECTIVE

This study aimed to use cone-beam computed tomography (CBCT) to evaluate the root anatomy and canal morphology of maxillary premolars in a Chinese population and determine their degree of bilateral symmetry.

DESIGN

774 CBCT images were retrospectively analyzed, representing 1387 maxillary first premolars and 1403 second premolars. The number of roots and canals were recorded. The morphology of root canal systems was determined according to Vertucci's classification. The symmetry of root and canal anatomies between maxillary contralateral premolars was further evaluated.

RESULTS

The most common anatomy of maxillary first and second premolars was one-rooted with two canals (58.0%) and one-rooted with one canal (50.3%), respectively. The typical canal morphology was type IV (42.7%) in maxillary first premolars and type I (50.3%) in maxillary second premolars. One-rooted maxillary premolars exhibited a higher variability in the canal morphology, compared to two-rooted or three-rooted teeth. Maxillary second premolars exhibited greater anatomic symmetry than first premolars. The root and canal numbers showed bilateral symmetry between 80.2% of maxillary first premolar pairs and 81.8% of second premolar pairs. Bilateral symmetry in both number and morphology of roots and canals was observed for 72.3% of maxillary first premolar pairs and 73.2% of second premolar pairs.

CONCLUSION

The root anatomy and canal morphology of maxillary premolars in a Chinese population were quite diversified. Maxillary contralateral premolars demonstrated a high degree of symmetry in root and canal anatomies, which enables practitioners to better determine the nature of the root canal system during treatment of opposite homonymous teeth.

A cone-beam computed tomography study of the mesial cervical concavity of maxillary first premolars

OBJECTIVE

To investigate the mesial cervical concavity of maxillary first premolars and its relationship with root and canal configuration using cone-beam computed tomography (CBCT).

DESIGN

Images of maxillary first premolars (n = 1056) were collected from patients (n = 601) who had undergonein vivo CBCT scanning. The root and canal number and morphology were evaluated. The following measurements of the mesial cervical concavity of the maxillary first premolars were evaluated in section images: dentine thickness (in concavity at the cemento-enamel junction), concavity angle, depression depth (distance from mesial dentinal surface at concavity to mesial proximity), concavity position (distance from mesial dentinal wall at invagination to the top of the mesial marginal ridge). The reliability of the data was analyzed with an unpaired Student's t test and Fisher's exact test.

RESULTS

The percentages of maxillary first premolars with one root, two, and three roots were 55.5%, 43.7%, and 0.8% respectively. Mesial cervical concavity was recorded in 64.5% of single-root maxillary premolars. The prevalence of two-root maxillary first premolars with mesial cervical concavity was 73.8%. The means of the aforementioned four measurements were 1.705, 147.9, 1.640, and 5.247 mm. The values of dentine thickness (mm), depression depth (mm), and concavity position (mm) of the mesial cervical concavity were largest in two-root maxillary first premolars. The smallest concavity angle of the mesial cervical concavity was found in three-root maxillary first premolars.

CONCLUSIONS

There is a high prevalence of mesial cervical concavity among maxillary first premolars. The mesial root concavity is more prevalent in single-rooted maxillary first premolars when there are two canals present, and its prevalence and degree of concavity increase with the number of roots.

Maxillary first premolars with three root canals: two case reports

It is very important that the dentists have sufficient information about possible variations in the expected root canal configurations in order to achieve success in endodontic treatment. In addition to having adequate knowledge on the variations of the root canal anatomy, periapical radiographs from different angles, careful examination of the pulp chamber floor, and use of dental operation microscope during the procedure are also important factors that contribute to the diagnosis of the additional roots and canals. The aims of this article are to present the diagnostic approach and root canal treatments of two maxillary first premolar teeth with three canals in two patients.