Number of roots and canals in maxillary first premolars: study of an Andalusian population

Characterization of the root and canal anatomy of maxillary premolar teeth in an Iraqi subpopulation: a cone beam computed tomography study

This study aims to evaluate the number of roots and root canal morphology types of maxillary premolars in relation to a patient's gender and age in an Iraqi population using two classification systems. Cone beam computed tomography (CBCT) scans of 1116 maxillary premolars from 385 patients were evaluated for the number of roots and root canal morphology types according to Vertucci's classification and Ahmed et al. classification systems. Differences in the number of roots and root canal morphology types with regard to tooth type, patients' gender and age groups were evaluated and the degree of bilateral symmetry was determined. Chi-squared test was used for statistical analysis. About 51.1% of the 1st premolars were double rooted. The majority (87.9%) of the 2nd premolars were single rooted. The three-rooted form presented in only 1.2% and 0.7% of the 1st and 2nd premolars, respectively. Vertucci Type IV (Ahmed et al. code 2MaxP B1P1) and Vertucci Type I (Ahmed et al. code 1MaxP1) were the most common canal morphology types in the 1st and 2nd premolars, respectively. Females showed a lower number of roots and a higher prevalence of Vertucci Type I configuration (P < 0.05). Younger age groups showed a higher prevalence of Vertucci Type I configuration (P < 0.05). Bilateral symmetry was seen in more than half of the maxillary premolars. There is a considerable variation in the number of roots and root canal configurations of maxillary premolars in the studied Iraqi population, with a significant difference by gender and age groups. Ahmed et al. classification provided more accurate presentation of the root and canal anatomy in maxillary premolars compared to Vertucci's classification.

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.

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.

Root and canal morphology of maxillary premolars and their relationship with the crown morphology

OBJECTIVES

To investigate the relationship between crown/root size and root/canal morphology of maxillary premolars.

METHODS

One hundred and thirty-three first (P1) and 110 second (P2) maxillary premolars were used. Mesiodistal and buccolingual diameters and root heights of P1 and P2 were recorded to the nearest 0.01 mm. The number of single and multi-rooted premolars was recorded based on the Turner's classification. Root canal morphology was studied using a clearing technique with Vertucci's classification. Pearson's correlation coefficient was used to analyze the relationship between tooth size and root/canal morphology.

RESULTS

Two-rooted P1 was found in 33.9% of male and 22.5% of female. P2 showed a single root in 85.4% of male and 82.6% of female. In case of P1, the number of root canals (P<0.05) and apical foramina (P<0.01) was significantly different between male and female. P1 crown dimensions were larger in double-rooted teeth than in single-rooted ones. Significant differences were observed in buccolingual (P<0.05) and crown area (P<0.05) in females. Root height was smaller in double-rooted than in single-rooted P1. A similar trend was observed for P2 with a larger crown size in teeth with two apical foramina compared with those with a single foramen.

CONCLUSIONS

Two-rooted P1 with two or more apical foramina are more commonly seen in males than in females. For P1, the correlation of number of roots and apical foramina was stronger with buccolingual diameter than with mesiodistal diameter in both genders. P1 and P2 with large crown dimensions tend to have multiple roots and apical foramina.

Canal Configuration of Maxillary Premolars in Cukurova Population: A CBCT Analysis

Background/Aim: Aim of this study was to evaluate the anatomy of root-canal systems and numbers of permanent maxillary premolars’ roots and canals, using cone beam computed tomography scans.

Material and Methods: In this retrospective and observational study, maxillary right/left and first/second premolars of patients who were screened with cone beam computed tomography for various reasons in a Turkish dental school, were examined. Evaluated parameters were age, gender, canal configuration (Vertucci classification) and numbers of roots and canals. Chi-square test was used for statistical analysis. The level of significance was set at p<0.05.

Results: A total of 1086 maxillary premolars including 555 first premolars and 531 second premolars were examined in 331 patients (186 female, 145 male). Presence of two roots was shown in 75% of first premolars. 76.3% of second premolars were found to have a single root. Most common canal configuration was type IV (73.2%) for first premolars and type II (32.4%) for second premolars. There was a significant relationship between gender and numbers of first and second premolars’ roots and canals.

Conclusions: High heterogeneity of maxillary premolar root-canal system anatomy should be considered during endodontic treatment.

Root form and canal anatomy of maxillary first premolars: a cone-beam computed tomography study

The aim of this study was to evaluate the root and canal morphology of permanent maxillary first premolars in a Polish population using cone-beam computed tomography scanning (CBCT) and to compare the classifications by Vertucci and Ahmed et al. Images of 350 maxillary first premolars were analyzed. Scans were obtained from 226 patients: 131 women and 95 men. The root canal configurations were classified according to Vertucci and a new system by Ahmed et al. In addition, the number of roots and the level where roots bifurcated were identified. The results were submitted to statistical analysis. Most maxillary first premolars had two roots (69.1%). Most bifurcations were located in the coronal part of the root (44.2%) and the least in the apical part (15.3%). Bifurcation in the coronal part of the root was observed more often in the teeth of men than women. In turn, bifurcation in the central or apical part was significantly more common in women than in men. The most common canal configuration of the maxillary first premolars was type IV (78.2%) according to Vertucci and ²FPB¹P¹ (65.4%) according to the new classification. Among the remaining cases, almost all types of canals described by Vertucci, and many combinations of codes given in the new classification were demonstrated. The maxillary first premolars displayed a wide range of root and canal anatomical variations. The new system for classifying canal morphology based on Ahmed et al. is more accurate than the Vertucci classification.

Assessment of root morphology and canal configuration of maxillary premolars in a Saudi subpopulation: a cone-beam computed tomographic study

BACKGROUND

The objective of this study was to use CBCT to look into the root canal morphology of maxillary premolars in a Saudi Arabian subpopulation and associate the results to existing canal morphology classifications.

METHODS

The sample size for this analysis was 500 right and left untreated maxillary first and second premolars with fully formed roots from 250 Saudi residents (125 male and 125 female). The following observations were made using CBCT on the teeth related: (1) The number and morphology of roots; (2) The canal morphology for each root according to Vertucci's classification. The frequency and similarities between the right and left sides, as well as between females and males, were studied. The Chi-square test was used to assess the results.

RESULTS

Of the 500 maxillary first premolars studied, 199 teeth had one root (39.8%), whilst 293 (58.6%) were two-rooted. Three-rooted maxillary first premolars were found in 8 (1.6%). For maxillary second premolars, 416 premolars had one root (83.2%), whilst 79 (15.8%) had two roots and the rest 5 (1.0%) were three roots. There were significant differences of number of root were found between groups (p > 0.05). For maxillary first premolar, Type IV was the most frequent, accounting for 57.8% of the sample (n = 289), followed by type II (32.8%, n = 164). For maxillary second premolar, Type I was mainly occurrence 302 (60.4%), followed by Type II (16.4%, n = 82).

CONCLUSIONS

The majority of maxillary first premolars had two roots and two root canals, while one root and one root canal was the most common anatomical configuration for maxillary second premolars. Additional canal forms do occur on occasion, and clinicians should pay close attention to them.

The effect of different confluence confirmation strategies on the obturation of Vertucci type II canal: micro-CT analysis

Objectives

The present study aims to compare the obturation quality of 2 confluence confirmation techniques in artificial maxillary first premolars showing Vertucci type II root canal configuration.

Materials and Methods

Thirty artificial maxillary premolars having Vertucci type II root canal configuration were made. They were divided into 3 groups according to the confluence confirmation technique as follows. Gutta-percha indentation (GPI) group (confluence confirmation using a gutta-percha cone and a K file); electronic apex locator (EAL) group (confluence confirmation using K files and EAL); and no confluence detection (NCD) group. In the GPI group and the EAL group, shaping and obturation were performed with the modified working length (WL). In the NCD group, shaping was performed without WL adjustment and obturation was carried out with an adjusted master cone. Micro-computed tomography was used before preparation and after obturation to calculate the percentage of gutta-percha occupied volume (%GPv) and the volume increase in the apical 4 mm. Data were analyzed using 1-way analysis of variance and post hoc Tukey's test.

Results

Statistically significant difference was not found in terms of the %GPv from the apex to apical 4 mm. However, the NCD group showed a statistically significant volume increase compared with the EAL group (p < 0.05).

Conclusions

In terms of gutta-percha occupied volume, no significant difference was observed among the 3 groups. Confluence confirmation using an EAL in teeth with Vertucci type II configuration showed less volume increase during canal shaping compared with no confluence confirmation.

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.

An efficacious horizontal angulation separated radiographically superimposed canals in upper premolars with different root morphologies

Objectives

To determine the effect of various horizontal beam angulations on radiographically separating superimposed canals in upper premolars with different external root morphologies.

Materials and methods

The independent variables were 1) three different external root morphologies of upper premolars (n = 30); one-root (A), fused-root (B) and two-root (C), 2) thirteen angulations (0° and mesial (Ms) and distal (Ds) shifts of 15, 20, 25, 30, 35, and 40°), and 3) the superimposed canal at the apex (apx) and 5-mm from the apex (5apx). The dependent variables were the percentage of radiographs demonstrating canal separation. The separated canal distances were analysed using analysis of variance (ANOVA) and Tukey HSD.

Results

Separation distances at apx and 5apx on one-root, fused-root and two-root premolar radiographs increased as the angulation increased. Ms angulations generated a higher separation distance (SepDist) in mm compared with the Ds angulations. Significantly different separation distances were observed from various horizontal shift angulations (p < 0.05). Percentage of canal separation from 0^o was achieved differently in different morphology of upper premolars (14-80%) at apx and 10-40% at 5apx. The 20-40Ms/Ds and 25Ds/30‒40Ms/Ds resulted in 100% of radiographs with canal separation for two-root and fused-root premolars, respectively, at apx and 5apx. Only the 35/40Ms resulted in 100% of radiographs with separation at apx in one-root teeth.

Conclusion

The ideal horizontal angulation which revealed the superimposed canal at the apx/5apx for one-root, fused-root, and two-root teeth are 35M/35M, 20D/20M, and 15M/20M, respectively.

Significance

The 25Ms was the optimal angulation which strongly recommended with the highest probability of separation and acceptable image quality in endodontic and prosthodontic treatment for unknown morphologies evaluated.

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 and canal configurations of maxillary premolars in a South African subpopulation using cone beam computed tomography and two classification systems

This cone beam computed tomography (CBCT) study aimed to describe the maxillary premolar anatomy of a South African subpopulation using two classification systems. A total of 601 premolars were evaluated. For each tooth, the root number and canal configurations were described using the classification systems devised by Vertucci (1984) and Ahmed et al. (2017). Correlations between root number and sex were determined using the chi-squared test (P = 0.05). Two roots were present in approximately half of all maxillary first premolars (54.1%, n = 171/316). The majority of maxillary second premolars displayed one root (78.2%, n = 223/285). Single-rooted maxillary second premolars were more common in females (P < 0.05). The Vertucci type IV configuration was most prevalent in the maxillary first premolars. In contrast, maxillary second premolars showed a greater tendency toward Vertucci's type I configuration. The classification proposed by Ahmed et al. indicated the most prevalent maxillary first premolar configuration to be ²MP B¹P¹. The most common configuration among the maxillary second premolars was ¹ MP¹. Diverse root and canal anatomical presentations were found in this subpopulation. Both classification systems adequately describe maxillary premolar anatomy; however, the system proposed by Ahmed et al. may more accurately describe complex teeth.

Maxillary Permanent First Premolars With Three Canals: Incidence Analysis Using Cone Beam Computerized Tomographic Techniques

Aim

This study aimed to analyze incidence of three canals in human permanent maxillary first premolar teeth using cone beam tomographic techniques.

Materials and Methods

The samples were divided into three groups namely Group (GP) I (single rooted [n = 255]), GP II (two rooted [n = 326]), and GP III (three rooted [n = 8)]. The teeth were processed, mounted in arches, coded, and subjected to cone beam tomographic scanning. Incidence of three canals was evaluated by cone beam tomography, compared, and statistically analyzed.

Results

The percentage of incidence of three canals in human permanent maxillary first premolar teeth was 1.7% and there was no statistically significant difference of incidence of three canals between studies using cone beam and non-cone beam methodologies.

Conclusion

Clinicians should be aware of the variations they may encounter when endodontically treating a maxillary first permanent premolar and should apply this knowledge in a clinical scenario systematically.

Root and canal morphology of maxillary premolar teeth in an Egyptian subpopulation using two classification systems: a cone beam computed tomography study

AIM

To investigate the number of roots and root canal configurations using two coding systems and the root canal diverging and merging levels in extracted maxillary premolars in an Egyptian subpopulation using cone beam computed tomography (CBCT).

METHODOLOGY

A total of 700 maxillary premolars were examined using CBCT in an Egyptian subpopulation. The number of roots was identified, and root canal configurations were classified according to Vertucci's classification and a new system for classifying root and canal morphology. In addition, the position where roots bifurcated and the levels where canals merged or diverged were identified. Fisher's exact test and independent t-test were used for statistical analysis, and the level of significance was set at 0.05 (P = 0.05).

RESULTS

More than half of maxillary first premolars were double-rooted, and the majority of maxillary second premolars were single-rooted (P < 0.001). Most of the double-rooted samples had bifurcations in the middle of the root. According to the Vertucci classification, canal configuration type IV was the most common in both first and second maxillary premolars. According to the new system, the code ² FP B¹ P¹ was the most common for maxillary first premolars, whilst ² SP B¹ P¹ , ¹ SP² and ¹ SP^2-1 codes were the most common for maxillary second premolars. The three-canalled morphology in double- and three-rooted maxillary premolars had considerable variations. Root canal merging and diverging levels were comparable in both tooth types.

CONCLUSION

Maxillary premolars in this Egyptian subpopulation had a wide range of root and canal anatomical variations. Clinicians should be aware of where canals merge and diverge to facilitate the treatment of all canals. The new system for classifying canal morphology describes the root and canal configurations in a more accurate and practical manner compared to the Vertucci classification.

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.

Root form and canal morphology of maxillary first premolars of a Yemeni population

BACKGROUND

The purpose of this study was to investigate variations in the root canal systems of permanent maxillary first premolars in a Yemeni population using a clearing technique.

METHODS

Two hundred fifty permanent maxillary first premolar teeth extracted from Yemeni individuals were collected. A small hole in the center of the occlusal surface of each tooth was prepared and pulp tissue was removed by immersion in 5.25% sodium hypochlorite. Teeth were stored in 5-10% nitric acid solution for 5-6 days. Next, teeth were rinsed, dried, and dehydrated using ascending concentrations of ethanol (70, 95, and 100%) successively for 12 h each. Waterproof black ink was injected into the dried dehydrated teeth. Stained teeth were then rendered clear by immersion in methyl salicylate solution (98%) until evaluation. Root canal morphology of each tooth was then examined.

RESULTS

54.8% of teeth were single-rooted, while 44.4% were double-rooted and only 0.8% had three separated roots. The most common canal system configuration was Vertucci type IV (55.6%). Eight specimens of the single-rooted premolars (3.2%) had new canal configurations that have not been recognized in previous published studies. Accessory canals and inter-canal communications were detected in a total of 52.8 and 34.4% of the specimens, respectively. The apical foramen was located centrally to the apex in 84.9% and apical deltas were found in 13.2% of the studied sample.

CONCLUSIONS

Yemeni permanent maxillary first premolars are mainly single-rooted and predominantly present Vertucci type IV canal morphology. The finding of additional canal configurations in this study is low but should be kept in mind when performing endodontic therapy for these teeth.

Root anatomy and apical canal morphology of maxillary first premolars

Understanding the root anatomy and apical canal morphology of maxillary premolars is a key prerequisite for successful surgical and endodontic treatment. The aim of this study was to assess the root anatomy and apical canal morphology of maxillary first premolars. To achieve the set task, 30 maxillary first premolars were extracted. After thorough rinse visual assessment of root anatomy was made. Each root was transversally sectioned six millimeters from apex with a straight hand piece. The apical samples were decalcificated in 7.5% trichloroacetic acid, transversal sections were made, stored in 10% formalin then dyed in hematoxylin and eosin and numerated from I to VI. Apical canal morphology was evaluated with an optical microscope. Majority of maxillary first premolars had double roots (63.0%; n=19) that were mostly separated (50.0%; n=15) containing a single root canal. Minority had double roots that were fused (13.0%; n=4) with two root canals. Single root with almost equal occurrence of two, as well as variable root canal configuration were found in (30.0%; n=9). A very rare occurrence of maxillary first premolars with three roots (7.0%; n=2) was detected, two vestibular and one palatal, each containing a single canal configuration. Accessory lateral canals were detected in 20% of maxillary first premolars. Transversal communications were detected in maxillary premolars with one root and double fused roots (26.6%; n=8). A single apical foramen was detected in majority of maxillary first premolars (50.0%; n=15). Two apical foramina were detected in (33.4%; n=10), three in (10.0%; n=3) and four in (6.6%; n=2) maxillary premolars. Keywords: maxillary first premolar, root anatomy, apical canal morphology, decalcification, optical microscopy

Incidence of Risk and Complications Associated with Orthodontic Therapeutic Extraction

Background:

Extraction in orthodontics are carried out in the cases where there is space deficiency to align the teeth. The elective extraction of first or second premolars has been discussed in the literature for more than 50 years. In the 1940s and 1950s Nance, Dewel and Carey reviewed this as a useful option, and in the 1970s Logan and other leading orthodontists favoured the extraction as choice. It is not always the elective extraction of premolar is a smooth drive for the surgeon as well as to patient. Sometimes the elective extraction of premolar result in complications, which might be due to both anatomical and surgical factors.

Methodology:

The study sample consisted of 100 patients referred for one or more orthodontic extractions to the department of oral and maxillofacial surgery were included in this retrospective study at the vivekanandha dental college for women tiruchengode between November 2014 and May 2016. All referrals were from the department of orthodontics. A survey was carried out to record the intraoperative risks and correlated with its morbidity as when occured. All intraoperative morbities were managed appropriately as required.

Result and Conclusion:

Between November 2014 and May 2016, 100 patients had one or more premolar teeth removed by the oral surgeons. The sample size was 100 patients who had a total of 334 premolars removed. The sample's mean age was 11.4+\- 8.4 years, and 57.0% were male. The average number of teeth extracted per patient was 2.34 +\- 1.46, and 73.8% had complete root development. More than 93.4% of subjects had normal root and bone morphology, whereas 35.65% had variations in root forms and bone texture. The intra-operative and post operative complication rates were 7.4% and 1.9%, respectively. Complications were generally minor (91.9%) and were managed nonoperatively on an outpatient basis. There were no case of oral antral communication.

Micro-CT Evaluation of Root and Canal Morphology of Mandibular First Premolars with Radicular Grooves

Abstract The aim of this study was to evaluate morphological features of 70 single-rooted mandibular first premolars with radicular grooves (RG) using micro-CT technology. Teeth were scanned and evaluated regarding the morphology of the roots and root canals as well as length, depth and percentage frequency location of the RG. Volume, surface area and Structure Model Index (SMI) of the canals were measured for the full root length. Two-dimensional parameters and frequency of canal orifices were evaluated at 1, 2, and 3 mm levels from the apical foramen. The number of accessory canals, the dentinal thickness, and cross-sectional appearance of the canal at different root levels were also recorded. Expression of deep grooves was observed in 21.42% of the sample. Mean lengths of root and RG were 13.43 mm and 8.5 mm, respectively, while depth of the RG ranged from 0.75 to 1.13 mm. Mean canal volume, surface area and SMI were 10.78 mm3, 58.51 mm2, and 2.84, respectively. Apical delta was present in 4.35% of the sample and accessory canals were observed mostly at the middle and apical thirds. Two-dimensional parameters indicated an oval-shaped cross-sectional appearance of the root canal with a high percentage frequency of canal divisions (87.15%). Canal configuration type V (58.57%) was the most prevalent. C-shaped configuration was observed in 13 premolars (18.57%), whereas dentinal thickness ranged from 1.0 to 1.31 mm. Radicular grooves in mandibular first premolars was associated with the occurrence of several anatomical complexities, including C-shaped canals and divisions of the main root canal.

Buccally impacted maxillary canines increase the likelihood of root separation in adjacent first premolars

OBJECTIVE

To investigate the influence of maxillary impacted canines on the root morphology of adjacent premolars in a Chinese population.

SUBJECTS AND METHODS

A sample of 370 Chinese subjects with maxillary canine impaction and 370 control subjects were collected in this study. CBCT data of all subjects were collected and analyzed. The prevalence of separate-rooted maxillary premolars was compared between subjects with and without impacted canines. Then, the prevalence of separate-rooted maxillary premolars was compared between subjects with buccal canine impaction (BIC) and those with palatal impaction (PIC).

RESULTS

The prevalence of separate-rooted first premolars was significantly higher in the canine impaction group (P = 0.046), but the prevalence of separate-rooted second premolars was not different (P = 0.780). Furthermore, a significant higher prevalence of first premolar root separation was found on the impacted site in the BIC subgroup (P < 0.001), but not in the PIC subgroup (P = 0.508). Also, the prevalence of separate-rooted first premolars in the BIC subgroup was significantly higher than that of the control group (P = 0.008), but not so for the PIC subgroup (P = 0.097).

CONCLUSIONS

Buccally impacted maxillary canines are associated with an increased prevalence of root separation in the adjacent maxillary first premolars. This is likely because that buccally impacted canines encroach on the space needed for root development of the first premolars.

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

INTRODUCTION

Sound knowledge of the external and internal morphology of the different teeth groups is essential to ensure a successful outcome of root canal treatment. The aims of this study were to review the available literature with respect to the root and root canal morphology of maxillary first premolars and discuss the clinical considerations of this morphology on the various dental procedures.

METHODS

The MEDLINE/PubMed and Scopus databases were searched for relevant literature. The identified publications were classified into anatomic studies and clinical case reports. The data extracted from anatomic studies were tabulated, and weighted averages for certain internal and external morphologic features were calculated. The anatomic and developmental variations in the clinical case reports were summarized.

RESULTS

A total of 92 studies (45 anatomic studies and 47 case reports) including a total of 11,299 teeth were identified. The majority of maxillary first premolars had 1 root (41.7%) or 2 roots (56.6%). Regardless of the number of roots, the vast majority (86.6%) had 2 root canals, with type IV (2-2) being the most common canal configuration (64.8%). The majority of the apical foramina (66.6%) did not coincide with the apical root tip. About 38% of the teeth had lateral canals, 12.3% had apical deltas, and 16.0% had isthmi. The clinical case reports showed that the 3-rooted variant was the most common anatomic variation, and developmental anomalies were rarely reported.

CONCLUSIONS

The maxillary first premolars are predominantly 2-rooted teeth with 2 root canals. However, the clinician should be aware about the possible anatomic variations of these teeth and their relationship with the adjacent anatomic structures while planning and performing endodontic, restorative, periodontal, and surgical procedures.

Variability in premolar and molar root number in a modern population of Pan troglodytes verus

While teeth are the most common fossil remains for hominoids, little is known of the tooth root morphology in Primates. With the exception of modern humans, the variability of the number of roots within a species is scarcely documented and not conclusively quantified. This lack of knowledge hinders the interpretation of observed evolutionary trends, such as the reduction of the number of roots of premolars within the hominins. Here, we present the first quantification of the variability of the number of roots in a nonhuman ape population including 405 specimens. Our sample is made of a single biological population of Pan troglodytes verus from Liberia, which is compared to other extant hominoids. Both permanent and deciduous teeth were analyzed and comprise premolars and molars from maxillaries and mandibles. The estimated variability is very low for each tooth position; more than 97% of the specimens displaying the same number of roots except for P4 (94%), M1 (89%), and P(4) (57%). No variability at all was observed for lacteal teeth. Males and females are statistically identical, and no difference linked to the tooth size (estimated by the occlusal surface) was observed. When compared to the observation in other hominoid species, these results emphasize that the difference of the number of roots observed between modern humans and apes is significant, and suggests that the evolution of premolar root number is mosaic, with the common ancestor of Pan and Homo probably displaying a reduced number of roots for P(4) and maybe P(3) , but a plesiomorphic morphology of the roots of lower premolars.

Morphology of root canals in lower human premolars

Background

The knowledge of the root canal morphology and the possible anatomical variations of mandibular premolars are important for the successful endodontic treatment of such cases. The aim of this study was to investigate the presence of two or three root canals in extracted first and second mandibular premolars which were collected from health centers in Syria.

Materials and Methods:

One hundred and ten human mandibular premolars (70 first premolars and 40 second premolars) with fully developed roots were investigated. After access the cavity of the teeth, the root canals were explored and radiographs were taken.

Results:

Premolars with one canal were found in 87% of cases (53% first premolar and 34% second premolar) and premolars with two canals were found in 12% of cases (10% first premolar and 2% second premolar). There was just one case (1%) where a first premolar had three canals. These differences were statistically significant with P<0.05.

Conclusion:

Clinicians should be aware of the anatomical variation in the mandibular premolars and be able to apply this knowledge in radiographical and clinical interpretation.

Root and canal morphology of Indian maxillary premolars by a modified root canal staining technique

The aim of this study was to investigate the root and canal morphology of maxillary first and second premolars in Indians by a modified canal staining and tooth clearing technique. Maxillary first (350) and second (350) premolars were collected, and the morphology and number of roots analyzed. After cleaning, the teeth were immersed in India ink and placed in a hyperbaric oxygen chamber at 0.6 MPa for 2 h. The teeth were then demineralized and cleared. Digital images of the teeth were examined under magnification to evaluate the number of root canals, root canal system configurations, number of apical foramina, and intercanal communications. Root canal configurations were identified based on Vertucci's classification and Gulabivala's additional classes. The most common root morphology of the first premolars was the classical two separate root morphology (a Caucasian trait) and that of the second premolars was a single-root morphology (a Mongoloid trait), though other morphologies such as singlerooted first premolars and three-rooted first and second premolars were also identified. A "radiculous" first premolar was identified in two samples. The buccal roots of the first premolar showed the maximum variation, the most common being type I (Vertucci's classification), followed by type IV. The highest incidence of intercanal communications was found in the single-rooted first premolars. All roots exhibiting type IV and V canal configurations showed two separate apical foramina, while additional type 2-3 canal configurations showed three separate apical foramina. The root number and morphology as well as the canal morphology of Indian maxillary premolars showed both Mongolian and Caucasian traits.

Root canals and apical foramina of the buccal root of maxillary first premolars with longitudinal sulcus

In the present study, periapical radiographs were analyzed to investigate the number of canals of the buccal root of maxillary 1st premolars with longitudinal sulcus, and compare the number of apical foramina observed on the radiographs to that revealed by scanning electron microscopy (SEM). Thirty-nine human maxillary 1st premolars had their crowns and palatal roots removed and the root canals (C) were explored with endodontic files until the tip of the instrument was visualized exiting the apical foramen/foramina (AF). Radiographs were taken with files inside the root canals and the specimens were classified as follows: 1C/1AF; 2C/2AF; 1C/2AF; 2C/1AF. Apices were examined under SEM and the number of apical foramina (considering those measuring >80 µm in diameter) was recorded. Only 17.1% (n=6) of the specimens had 1C/1AF; 77.2% (n=27) had 2AF in which 42.9% (n=15) had 2C and 34.3% (n=12) had 1C; 5.7% (n=2) had 2C/1AF. SEM examinations showed that 46.1% (n=18) of the specimens had 2AF; 23.1% (n=9) had 1AF; 23.1% (n=9) had 3AF; 7.7% (n=3) had 4AF. Radiographic and SEM findings for the number of AF coincided in 62.8% of the cases. A buccal longitudinal sulcus in the maxillary 1st premolar is usually accompanied by total bifurcation (42.9%) or apical bifurcation (34.3%) of the root canal. SEM identified a statistically higher number of apical foramina than radiographs (p<0.01).