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Introduction: The primary aim of the study is to evaluate the morphological form of the maxillary first premolar using 2D geomorphometry and evaluate the sexually dimorphic characteristics., Methods: The present study was carried out on standardized photographs of right Maxillary first premolar from 120 dental casts (60 male and 60 females). Twenty landmarks (based on geometric and anatomic evidence) were marked on the tooth using TPSdig software and analysed using Morpho J applying procrustes analysis and discriminant function analysis., Results: The results showed similar centroid sizes between gender (p = 0.541). Procrustes ANOVA for shape analysis showed a greater dimorphism between sexs (f value of 1.35; p value=0.0793).  Discriminant function analysis based on the procrustes coordinates showed an overall accuracy of 74.2 % in classifying sex based on the landmark coordinates with correct classification of  48/60 (80.00%) females and 41/60 (68.33) males., Conclusion: Shape of the tooth can be measured objectively using geometric morphometric methods which can be utilized to identify the sex of an individual. The enamel is derived from ectoderm and once formed does not change during the life. The tooth's structure and shape are determined by the sex chromosomes, which is well represented as sexual dimorphism. The study evaluates the occlusal and contact area morphology of premolars. These are important parameters considered during restorative treatment, functional rehabilitation and forensic investigations., Competing Interests: No competing interests were disclosed., (Copyright: © 2024 Natarajan S et al.)

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 variety of shapes has been reported for the roots and root canals of maxillary first premolars. The purposes of the present study were to determine branching and shapes of the roots of maxillary first premolars, as well as age-related changes using slice images obtained with cone-beam computed tomography (CBCT) for dental use. CBCT-reconstructed images of 125 cases that included maxillary first premolars were used as subjects. Slice images at the cervical one-third, center, and apical one-third positions of the root were prepared. Root branching and number of root canals was determined at each measurement position in the images. The subjects were divided into three groups: younger than 30 years, 30 to 50 years, and over 50 years. The root canal morphology was compared among these age groups. Single-rooted premolars were the most frequent. As for number of root canals, a single-canal premolar was observed at the position of the cervical one-third in 33.6%, at the center in 35.2%, and at the apical one-third in 56.0%. Thereafter the subjects were divided into groups by age, namely, younger than 30 years, 30 to 50 years, and over 50 years old, and it was revealed that the ratio of the two-canal type increased with age. In regard to tooth morphology, it was confirmed that the two-canal type shows more frequent occurrence with aging in maxillary first premolar. Based on our findings, we consider that CBCT can be useful for determining the root canal morphology with complicated shapes.

By means of a finite element method (FEM), the present study evaluated the effect of fiber post (FP) placement on the stress distribution occurring in endodontically treated upper first premolars (UFPs) with mesial-occlusal-distal (MOD) nanohybrid composite restorations under subcritical static load. FEM models were created to simulate four different clinical situations involving endodontically treated UFPs with MOD cavities restored with one of the following: composite resin; composite and one FP in the palatal root; composite and one FP in the buccal root; or composite and two FPs. As control, the model of an intact UFP was included. A simulated load of 150 N was applied. Stress distribution was observed on each model surface, on the mid buccal-palatal plane, and on two horizontal planes (at cervical and root-furcation levels); the maximum Von Mises stress values were calculated. All analyses were replicated three times, using the mechanical parameters from three different nanohybrid resin composite restorative materials. In the presence of FPs, the maximum stress values recorded on dentin (in cervical and root-furcation areas) appeared slightly reduced, compared to the endodontically treated tooth restored with no post; in the same areas, the overall Von Mises maps revealed more favorable stress distributions. FPs in maxillary premolars with MOD cavities can lead to a positive redistribution of potentially dangerous stress concentrations away from the cervical and the root-furcation dentin.

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., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Journal of Pharmacy and Bioallied Sciences.)

Background: There are a few studies about the evaluation of maxillary first premolars internal structure with micro-computed tomography (micro-CT). The aim of this study was to assess morphological features of the pulp chamber in maxillary first premolar teeth using micro- CT., Methods: Extracted 15 maxillary first premolar teeth were selected from the patients who were in different age groups. The distance between the pulp orifices, the diameter of the pulp and the width of the pulp chamber floor were measured on the micro-CT images with the slice thickness of 13.6 µm. The number of root canal orifices and the presence of isthmus were evaluated., Results: The mean diameter of orifices was 0.73 mm on the buccal side while it was 0.61 mm on palatinal side. The mean distance between pulp orifices was 2.84 mm. The mean angle between pulp orifices was -21.53°. The mean height of pulp orifices on the buccal side was 4.32 mm while the mean height of pulp orifices on the palatinal side was 3.56 mm. The most observed shape of root canal orifices was flattened ribbon. No isthmus was found in specimens., Conclusion: Minor anatomical structures can be evaluated in more detail with micro-CT. The observation of the pulp cavity was analyzed using micro-CT., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

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., Competing Interests: There are no conflicts of interest.

This study was to compare the influence of glass fiber post placement and crown restoration on endodontically treated maxillary first premolars with severe NCCLs using three-dimensional finite element analysis and fracture resistance testing. G1, intact teeth. G2, teeth with artificial defect. G3, composite resin (CR). G4, CR and fiber post in buccal canal (FPB). G5, CR and fiber post in palatal canal (FPP). G6, CR and fiber posts in buccal and palatal canals (FPBP). G7, CR and crown (C). G8, CR, FPB, C. G9, CR, FPP, C. G10, CR, FPBP, C. Teeth in G2, G3, and G5 showed a similar stress concentration at the tip of the defect. The fracture resistance of G2 did not differ significantly from G3 and G5 (p>0.05) but differed significantly from that in other groups (p<0.05). The fractures in G4 were more favorable, and the difference of those in G1 from those in G7, G8, G9, and G10 was statistically significant (p<0.05). Restoration of root-filled maxillary premolars with severe NCCLs using fiber post in the buccal canal may be more efficacious than other restoration methods.

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.

This article presented a case of discovering and diagnosing three roots with four canals of the maxillary first premolar. We found and located the extra root canal by clinical diagnosis, careful observation during the operation, and multiangle X-ray. We further confirmed the existence of the three roots with four canals with the help of cone-beam computed tomography. Finally, we verified the success of the high-quality root-canal therapy through root optical microscopy.

Introduction: The aim of this study was to compare the dentine removing efficacy of Gates-Glidden drills with hand files, ProTaper and OneShape single-instrument system using cone-beam computed tomography (CBCT)., Methods and Materials: A total of 39 extracted bifurcated maxillary first premolars were divided into 3 groups ( n =13) and were prepared using either Gates-Glidden drills and hand instruments, ProTaper and OneShape systems. Pre- and post-instrumentation CBCT images were obtained. The dentin thickness of canals was measured at furcation, and 1 and 2 mm from the furcation area in buccal, palatal, mesial and distal walls. Data were analyzed using one-way ANOVA test. Tukey's post hoc tests were used for two-by-two comparisons., Results: Gates-Glidden drills with hand files removed significantly more ( P <0.001) dentine than the engine-driven systems in all canal walls (buccal, palatal, mesial and distal). There were no significant differences between OneShape and ProTaper rotary systems ( P >0.05)., Conclusion: The total cervical dentine removal during canal instrumentation was significantly less with engine-driven file systems compared to Gates-Glidden drills. There were no significant differences between residual dentine thicknesses left between the various canal walls.