Permanent Maxillary Premolars Research Articles

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.

Three-Dimensional Evaluation of the Root Apex of Permanent Maxillary Premolars: A Multicentric Study

Aim: Modern endodontics has advanced radically in the recent years, and recently, it has been focused on the concept of mini-invasive treatments. This study aimed to evaluate the sections of the root apices at 1 mm from the radiographic apex using a high-resolution CBCT. Materials and Methods: The current study was performed in three different dental centers. One hundred maxillary permanent premolars (50 first and 50 s premolars) were analyzed using measurement software of the CBCT radiographic pictures. The mesio-distal (M-D) and bucco–palatal (B-P) sections were measured at 1 mm from the radiographic apex of each root. The section of 0.3 mm or less, 1 mm from the anatomical apex of the upper premolars, was decided as the limit value. All values were statistically analyzed. Results: The mean value in the 304 sections analyzed was 1.03 (±0.37). Only 19 sections (6.3%) had measurements less than or equal to 0.3 mm. All these 19 sections were from first premolars (p = 0.002). Conclusions: Based on the data obtained, the authors recommend performing conservative shaping when endodontically treating first maxillary premolars, especially when a pre-operative CBCT to evaluate the actual apical dimensions cannot be acquired.

Evaluation of Immediate and Delayed Microleakage of Class V Cavities Restored with Chitosan-incorporated Composite Resins: An In Vitro Study.

ABSTRACTAim and objectiveTo evaluate and compare the microleakage of unmodified microhybrid composite and 0.2% chitosan-incorporated composite in class V cavities restored immediately and after 3 months of storage in artificial saliva.Materials and methodsSixty human permanent maxillary premolars were collected and standardized class V cavity prepared on the buccal surface of each tooth with dimensions: mesiodistally 3 mm, occluso cervically 2 mm, and depth of 1.5 mm and restored with microhybrid composite and chitosan-incorporated composite resins respectively and randomly divided: Group I: control-microhybrid composite (n = 30): (a) 15 teeth tested immediately (b) 15 teeth tested after 3 months. Group II–restored with chitosan + composite (n = 30): (a) 15 teeth tested immediately (b) 15 teeth tested after 3 months. Specimens were stored in artificial saliva following which a dye extraction test was carried out using a spectrophotometer.ResultsThere was no statistically significant difference in microleakage score between the chitosan-composite group and unmodified composite group when evaluated immediately after placing the restoration. Microleakage values of the unmodified composite group increased significantly after 3 months of storage in artificial saliva and values of the chitosan-composite group did not differ significantly even after 3 months of storage. Microleakage was seen significantly less in the chitosan-composite group compared to the unmodified composite group after 3 months of storage in artificial saliva.ConclusionIt can be concluded that chitosan-incorporated composite seems to have improved mechanical properties and forms a more stable bond when compared with unmodified microhybrid composite in addition to being antibacterial.Clinical significanceConsidering the advantageous properties of this material, it may be clinically useful in restoring class V cavities in patients with high caries risk. However, further in vitro and in vivo studies need to be carried out.How to cite this articleDeb A, Pai V, Nadig RR. Evaluation of Immediate and Delayed Microleakage of Class V Cavities Restored with Chitosan-incorporated Composite Resins: An In Vitro Study. Int J Clin Pediatr Dent 2021;14(5):621–627.

Comparison of Dentinal Tubule Penetration between a Calcium Silicate-Based Sealer with Ultrasonic Activation and an Epoxy Resin-Based Sealer: A Study Using Confocal Laser Scanning Microscopy.

Objective The aim of this study was to compare the degree of dentinal penetration between an epoxy resin-based sealer applied by using two different filling methods and an ultrasonically activated calcium silicate-based sealer via confocal laser scanning microscopy (CLSM). Materials and Methods Forty-five extracted permanent maxillary premolars with type II canals (Vertucci’s classification) were subjected to the experiment. The root canals were instrumented and distributed randomly into the following three groups: AH Plus + continuous wave technique (AHC group); AH Plus + single cone technique (AHS group); and Endoseal MTA + single cone technique with ultrasonic activation (EMS) group. Each sealer was labeled with rhodamine B dye to allow visualization under CLSM. The sealer penetration depth in each sample was observed at 2 mm and 5 mm from the apex by using CLSM. The data were statistically analyzed by using analysis of variance or Kruskal–Wallis H test according to normality of variable (α = 0.05). Results In all groups, the maximum sealer penetration depth, mean fluorescence intensity, and sum fluorescence intensity values were higher at the 5-mm level than at the 2-mm level. At the 5-mm level, the EMS group showed the lowest value ( p = 0.02). At the 2-mm level, there were no statistically significant differences among any of the groups. The AHC group showed higher values than the other groups, but there was no statistically significant difference in the apical area where access of instruments was difficult. Conclusion The AHC group showed the highest dentinal tubule penetration, but had questionable filing efficacy in the apical area, which is of particular importance for the success of root canal treatment. Therefore, in areas such as the apical 2 mm of premolars with type II canals, which are difficult to access by using instruments such as heat carriers, other appropriate approaches may be required accordingly.

Evaluation of Microleakage of Micro Hybrid Composite Resins versus Chitosan-Incorporated Composite Resins When Restored in Class V Cavities Using Total Etch and Self-Etch Adhesives: An In vitro Study.

Aim:To evaluate the in-vitro microleakage of traditional micro hybrid composite resin and 0.2% chitosan-incorporated composite resin when restored in Class V cavities using total etch versus self-etch adhesives after storing in artificial saliva for 24 h.Materials and Methodology:Sixty permanent maxillary premolars collected and Class V cavities were prepared on buccal surface of each tooth (dimensions: mesio-distally 3 mm, occluso cervically 2 mm, and depth of 1.5 mm) and restored with Group 1: micro hybrid (30 teeth) and Group 2: chitosan-incorporated composite (30 teeth), which was further subdivided into: (a) 15 teeth using total-etch adhesives. (b) 15 teeth using self-etch adhesives. Next dye extraction test was carried out using spectrophotometer.Results:Comparison within groups: In Group 1: Self-etch demonstrated less microleakage (0.0129) compared with total etch (0.0183). The difference was statistically significant, and in Group 2: No statistically significant difference was found in mean microleakage scores after using either self-etch (0.0118) or total etch adhesives (0.0120).Conclusion:It can be concluded that chitosan-incorporated composite seems to have improved mechanical properties with a stable bond when used with either self-etch or total etch adhesives in addition to being antibacterial. It may be clinically useful in restoring Class V cavities in patients with high caries risk. However, further in vitro and in-vivo studies need to be carried out.

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.

Marginal adaptation and fracture resistance of feldspathic and polymer-infiltrated ceramic network CAD/CAM endocrowns for maxillary premolars.

The aim of this study was to evaluate the marginal adaptation and fracture resistance of feldspathic and Polymer-Infiltrated Ceramic Network (PICN) CAD/CAM endocrowns for maxillary premolars. Twenty extracted human permanent maxillary premolars were randomly divided into two groups (n = 10); Group CEREC (GC), which was produced by feldspathic ceramic and the Group Enamic (GE), which was produced by PICN. All teeth were endodontically treated and decoronated horizontally at 2 mm above the cemento-enamel junction. Endocrown preparations were done with 4 mm depth into the pulp chamber. Endocrowns were manufactured using CAD/CAM from ceramic blocks. Following adhesive cementation, all specimens were subjected to thermocycling. Marginal adaptation evaluated under SEM at 200 × magnification. Each specimen was fixed in a universal testing machine and a compressive load was applied at 45° to long axis of the teeth until failure. Failure load was recorded and failure modes were evaluated. Statistical analyses were performed with SPSS 19.0 software and data were compared using Mann-Whitney U test. There were no significant differences in the marginal adaptation between two groups (P > 0.05). GE presented significantly higher fracture resistance when compared to GC (P < 0.05). Failure pattern was similar and characterized by the tooth-ceramic fracture on the force-applied side. CAD/CAM fabricated feldspathic ceramic and PICN endocrowns provide sufficient marginal adaptation, but the PICN endocrowns shows higher fracture resistance than the feldspathic ceramic endocrowns.

PERMANENT MAXILLARY PREMOLARS WITH THREE CANALS- A CASE REPORT

Maxillary first premolar is a bi-rooted tooth with several variations in the root canal morphology. Usually it has 2 canals, however at times there could be an additional third canal present which could easily be missed by the clinician owing to lack of awareness and knowledge about the canal variations. Awareness of internal and external anatomy of tooth and also about its variations are essential for successful endodontic therapy. Prevalence of three canals in maxillary premolar is very low. This case report describes the endodontic management of permanent maxillary premolars with three root canals

An Evaluation of Shear Bond Strength of Admira (Ormocer) as an Alternative Material for Bonding Orthodontic Brackets: An In vitro Study.

Objective:To evaluate shear bond strength (SBS) of Ormocer-bonded orthodontic brackets with self-etching primer (SEP) and conventional adhesive system and also to assess the amount of adhesive remaining on the tooth surface after debonding using adhesive remnant index (ARI).Materials and Methods:The study was done on 90 extracted human upper first permanent maxillary premolars. The study sample was categorized into three groups of 30 each to assess the SBS using three adhesives, Ormocer, SEP, and conventional adhesive system. Following debonding, the surfaces of teeth were examined for residual adhesive remaining by means of the optical stereomicroscope at ×50 magnification. ARI (Artun and Bergland) was used to classify the amount of residual adhesive. Obtained data were expressed as mean ± standard deviation, and obtained data was expressed as mean ± standard deviation (SD) and statistical analysis was done using one way ANOVA and Mann-Whitney U-test [SPSS version 17 statistical package (SPSS Inc., Chicago, IL)].Results:The mean SBS was maximum in Group I followed by Group II and Group III. The difference in the mean SBS among Group I (8.67 ± 1.84 Mpa), Group II (7.72 ± 1.82 MPa) and Group III (6.42 ± 1.55 MPa) was statistically significant. ARI was maximum in Group I followed by Group II and minimum Group III.Conclusion:Ormocer may be utilized as a substitute to generally used bisphenol A-glycidyl methacrylate-based adhesives; however, its effectiveness should be determined clinically by in vivo studies.

The Effects of Tricalcium Phosphate and Novamin Remineralizing Agents on Microhardness of Bleached Enamel with 35% Hydrogen Peroxide-An In vitro Study

Objectives: The aim of the present study was to evaluated the effects of remineralizing agents (Tricalcium phosphate and Novamin) on microhardness of bleached enamel surface with 35% hydrogen peroxide (in office).Materials and Methods: Forty human permanent maxillary premolars free from caries or enamel malformation were used. The teeth were sectioned transversally across the cemento-enamel junction, and specimens were embedded in self-cure acrylic. The labial enamel surface faced upward and then they were ground flat and polished with silicon carbide abrasive papers. A total specimen were prepared and kept in deionized water. Then the specimens were drying subjecting them for baseline microhardness testing (control). The dental bleaching treatment was performed just on the labial enamel surface of the specimens using a commercial 35% hydrogen peroxide Whitness HP bleaching gel (in-office ).It was used according to the manufacture instruction. Microhardness was tested for all specimens after bleaching. Specimens were divided into two groups according to remineralizing agent n=20, Group I: Treated by NUPRO Sensodyne with NovaMin, Group II: Treated by Clinpro™ White Varnish Tri-Calcium Phosphate. The remineralizing agent was applied for three minutes per day. Two remineralizing agents were applied for fourteen consecutive days. After each application procedure, the specimens were washed with deionized water and then kept in artificial saliva. At the end of the fourteen days the remineralized specimens were subjected to microhardness testing and values were recorded. All the data were analyzed by ANOVA and Tukey’s post hoc test. Results: Results revealed that a statistically significant decrease on mean microhardness values after enamel bleaching compared to control, followed by a significant increase on mean microhardness after the application of the both remineralizing agents. One way-ANOVA showed a statistically insignificant difference between NUPRO Sensodyne with NovaMin and Clinpro™ White Varnish at p≥0.05.Conclusions: Based on the results of this in vitro study both Tricalcium phosphate and Novamin are effective in remineralization of bleached enamel surface and no significant difference was detected in their efficacy.

Ceramic Inlays: Effect of Mechanical Cycling and Ceramic Type on Restoration-dentin Bond Strength

This study aimed to evaluate the bond strength between dentin and five different ceramic inlays in permanent maxillary premolars, with and without mechanical cycling. One hundred permanent maxillary premolars were prepared and divided into 10 groups (n=10) according to the ceramic system (IPS e.Max Press; IPS e.Max CAD; Vita PM9; Vita Mark II; and Vita VM7) and the mechanical cycling factor (with and without [100 N, 2 Hz, 1.2×10(6) cycles]). The inlays were adhesively cemented, and all of the specimens were cut into microbars (1×1 mm, nontrimming method), which were tested under microtensile loading. The failure mode was classified and contact angle, roughness, and microtopographic analyses were performed on each ceramic surface. The mechanical cycling had a significant effect (p=0.0087) on the bond strength between dentin and IPS e.max Press. The Vita Mark II group had the highest bond strength values under both conditions, with mechanical cycling (9.7±1.8 MPa) and without (8.2±1.9 MPa), while IPS e.Max CAD had the lowest values (2.6±1.6 and 2.2±1.4, respectively). The adhesive failure mode at the ceramic/cement interface was the most frequent. Vita Mark II showed the highest value of average roughness. IPS e.max Press and Vita Mark II ceramics presented the lowest contact angles. In conclusion, the composition and manufacturing process of ceramics seem to have an influence on the ceramic surface and resin cement bond strength. Mechanical cycling did not cause significant degradation on the dentin and ceramic bond strength under the configuration used.

Anterior and middle superior alveolar block is efficient for maxillary premolar teeth extractions regardless of the injection system or anesthetic with adrenaline used

The anterior and middle superior alveolar nerve block was claimed to be unpredictably efficient for clinical application. The aim of this report was to establish the efficacy of the anterior and middle superior alveolar nerve block, applied with a computer-controlled injection system or a conventional syringe, for upper premolars extraction. Sixty healthy adults were divided into two groups regarding the device used as follows: the first group was injected by a computer-controlled injection system, and the second group by a conventional syringe. Pain ratings were obtained via a visual analog scale (VAS) and a verbal rating scale (VRS). Anterior and middle superior alveolar injection enabled a painless extraction in all patients, regardless of the local anesthetic or injection system used. It was slightly less painful when administered by a computer-controlled injection system, but insignificantly when evaluated by VRS. The anterior and middle superior alveolar nerve block may be recommended if maxillary permanent premolars have to be extracted.

Impact of Various Irrigating Agents on Root Fracture: An in vitro Study.

Irrigating solutions are used for cleaning and removing dentinal debris, and the other remains from pulpal space during biomechanical preparation. Therefore, we evaluated the impact of various irrigating agents on root fracture at 5-minute time exposure. We sectioned 60 permanent maxillary premolars with fully formed root structures transversely maintaining the root length of approximately 14 mm. Five study groups were made comprising ethylenediaminetetraacetic acid (EDTA), cetrimide, citric acid, and so on as various irrigating agents. A universal force test machine was used to calculate the force which was enough to fracture each root. Analysis of variance (ANOVA) test was used to access the level of significance. About 10% citric acid solution as an irrigating agent showed minimal fracture opposing results, whereas 10% EDTA solution showed the maximum fracture resistance of root portion. Selection of suitable EDTA concentration that has minimal adverse effect on the mechanical properties of the tooth is very important for the successful management of tooth fracture. About 10% EDTA provided the highest fracture resistance, necessitating the use of irrigating solution in root canal therapy (RCT). Further research with higher and different study groups is required to search for more efficient irrigating solution to improve the outcome of RCT.

Enamel matrix derivative promotes reparative processes in the dental pulp.

During odontogenesis, amelogenins from the preameloblasts are translocated to differentiating odontoblasts in the dental papilla, suggesting that amelogenins may be associated with odontoblast changes during development. In the present study, we have explored the effects of enamel matrix derivative (EMD) on the healing of a pulpal wound. Coronal pulp tissue of permanent maxillary premolars of miniature swine were exposed through buccal class V cavities. The exposed pulp was capped with EMD. The contralateral teeth served as controls and were capped with a calcium hydroxide paste (Dycal). The cavities were sealed with glass-ionomer cement. After 2 and 4 weeks, the histology of the teeth was analyzed. In the EMD-treated teeth, large amounts of newly formed dentin-like hard tissue with associated formative cells outlined the pulpal wound separating the cavity area from the remaining pulp tissue. Inflammatory cells were present in the wound area but not subjacent to the newly formed hard tissue. Morphometric analysis showed that the amount of hard tissue formed in EMD-treated teeth was more than twice that of the calcium-hydroxide-treated control teeth (p < 0.001), suggesting that EMD is capable of promoting reparative processes in the wounded pulp more strongly than is calcium hydroxide.