Chamber Floor Research Articles

Root canal treatment of a maxillary second molar with four mesiobuccal root canals – a case report

Among the roots of maxillary molars, the mesiobuccal often presents with a root canal system that may be complex and variable, leading to a greater challenge when trying to achieve a proper chemo-mechanical preparation. The present report intends to show a successful root canal treatment of a maxillary second molar with six root canals, of which four were present in the mesiobuccal root. After being diagnosed with pulp necrosis and symptomatic apical periodontitis, a molar was endodontically treated. It also had an uncommon paracone cusp. A careful inspection of the pulp chamber floor revealed a mesiopalatal sulcus, which, after exploration with ultrasonic tips under an operating microscope magnification, showed three additional mesiobuccal root canals. After proper mechanical debridement, disinfection with sodium hypochlorite, and warm gutta-percha obturation, a favorable outcome was observed at the 12-month follow-up.

Chromitite layers indicate the existence of large, long-lived, and entirely molten magma chambers

The classical paradigm of the ‘big magma tank’ chambers in which the melt differentiates, is replenished, and occasionally feeds the overlying volcanos has recently been challenged on various grounds. An alternative school of thought is that such large, long-lived and largely molten magma chambers are transient to non-existent in Earth’s history. Our study of stratiform chromitites in the Bushveld Complex—the largest magmatic body in the Earth’s continental crust—tells, however, a different story. Several chromitites in this complex occur as layers up to 2 m in thickness and more than 400 kms in lateral extent, implying that chromitite-forming events were chamber-wide phenomena. Field relations and microtextural data, specifically the relationship of 3D coordination number, porosity and grain size, indicate that the chromitites grew as a 3D framework of touching chromite grains directly at the chamber floor from a basaltic melt saturated in chromite only. Mass-balance estimates imply that a few km thick column of this melt is required to form each of these chromitite layers. Therefore, an enormous volume of melt appears to have been involved in the generation of all the Bushveld chromitite layers, with half of this melt being expelled from the magma chamber. We suggest that the existence of thick and laterally extensive chromitite layers in the Bushveld and other layered intrusions supports the classical paradigm of big, albeit rare, ‘magma tank’ chambers.

Confirmation Dynamics: Differential Vetting in the Appointment of US Federal Agency Leaders

Confirmation delay is decomposed to better understand both when and why the Senate augments its efforts to vet presidential nominees. Distinctions among expedited, normal, and protracted confirmation processes are analyzed, as well as those between the work of Senate standing committees and chamber floor. A theory of ex ante moral hazard reduction is proposed that predicts as the confirmation process becomes increasingly protracted in response to rising potential agency costs, the Senate will be increasingly swifter to confirm tier 1 top executive leaders to US federal agency leadership positions than tier 2 subordinate leadership nominees. The statistical evidence is consistent with this theory of differential vetting between nominee tiers for both Senate party polarization and the nominee’s loyalty to the appointing president, as well as for agency decision-making independence restricted to protracted confirmation processes. Yet, such differential vetting is not empirically observed in response to interbranch policy conflict.

Survival of Escherichia coli in Airborne and Settled Poultry Litter Particles

Simple SummaryAirborne transmission is recognized as an important mechanism of disease spreading in livestock and poultry production, yet is far from being fully understood. Evaluating the impact of airborne transmission requires information of the microbial survivability. We determined the survivability of the E. coli—a common microbial species found in poultry environment—in airborne particles, settled dust, and poultry litter under laboratory environmental conditions. The poultry litter which contained mainly manure mixed with fresh wood shavings was collected from a commercial farm. Results of the study showed that the half-life time of airborne E. coli was 5.7 ± 1.2 min. The half-life time of E. coli in poultry litter and settled particles was 15.9 ± 1.3 h and 9.6 ± 1.6 h, respectively. The findings of this study will help better estimate the impact of airborne transmission of E. coli in poultry production.Airborne Escherichia coli (E. coli) in the poultry environment can migrate inside and outside houses through air movement. The airborne E. coli, after settling on surfaces, could be re-aerosolized or picked up by vectors (e.g., caretakers, rodents, transport trucks) for further transmission. To assess the impacts of airborne E. coli transmission among poultry farms, understanding the survivability of the bacteria is necessary. The objective of this study is to determine the survivability of airborne E. coli, settled E. coli, and E. coli in poultry litter under laboratory environmental conditions (22–28 °C with relative humidity of 54–63%). To determine the survivability of airborne E. coli, an AGI-30 bioaerosol sampler (AGI-30) was used to collect the E. coli at 0 and 20 min after the aerosolization. The half-life time of airborne E. coli was then determined by comparing the number of colony-forming units (CFUs) of the two samplings. To determine the survivability of settled E. coli, four sterile Petri dishes were placed on the chamber floor right after the aerosolization to collect settled E. coli. The Petri dishes were then divided into two groups, with each group being quantified for culturable E. coli concentrations and dust particle weight at 24-h intervals. The survivability of settled E. coli was then determined by comparing the number of viable E. coli per milligram settled dust collected in the Petri dishes in the two groups. The survivability of E. coli in the poultry litter sample (for aerosolization) was also determined. Results show that the half-life time of airborne E. coli was 5.7 ± 1.2 min. The survivability of E. coli in poultry litter and settled E. coli were much longer with the half-life time of 15.9 ± 1.3 h and 9.6 ± 1.6 h, respectively. In addition, the size distribution of airborne E. coli attached to dust particles and the size distribution of airborne dust particles were measured by using an Andersen impactor and a dust concentration monitor (DustTrak). Results show that most airborne E. coli (98.89% of total E. coli) were carried by the dust particles with aerodynamic diameter larger than 2.1 µm. The findings of this study may help better understand the fate of E. coli transmitted through the air and settled on surfaces and evaluate the impact of airborne transmission in poultry production.

A Radio-Odontometric Analysis of Sexual Dimorphism in First Molars Using Cone-Beam Computed Tomography.

Different techniques for sex prediction are developed and used in the forensic medicine field. One of these methods is based on the teeth morphometry. The aim of the present study was to evaluate the degree of sex determination of the maxillary and mandibular first molar teeth in cone beam computed tomography images. This study was carried out on cone beam computed tomography images of 100 men and 100 women with a mean age of 21.28 ± 2.47 years. The roof, floor and height of pulp chamber, as well as marginal enamel thickness and dentin thickness at the height of contour, tooth width, and crown length were measured. Student t test and discriminant analysis were applied to assess the differences in the measured parameters between men and women. According to the present study, the maxillary first molar was more dimorphic than the mandibular teeth. The accuracy of sex identification of mandibular and maxillary first molar tooth was 84% and 77%, respectively. The mesiodistal measured variables were more accurate in sexual differentiation than the buccolingual ones. For sex differentiation, the most dominant variables for maxillary and mandibular first molar teeth were crown height and dentin thickness, respectively. The first molar tooth showed an acceptable level of sex determination accuracy based on the odontometric measurements.

Biomechanical behavior of endocrown restorations with different cavity design and CAD-CAM materials under a static and vertical load: A finite element analysis

Statement of problemThe influence of different restorative materials, the divergence angle, and the preparation design of the pulp chamber floor in endocrowns on stress distribution is unclear. PurposeThe purpose of this finite element analysis study was to evaluate the stress distribution and maximum von Mises stress values in endocrown restorations and remaining teeth. Material and methodsAn endodontically treated first mandibular molar was prepared with 2-mm occlusal reduction, a butt-joint margin, and a mesial box with a 4-mm buccolingual extension to receive an endocrown restoration. The model was then scanned, and the exported standard tessellation language file was designed according to the anatomic references by using a computer-aided design software program. The reference model was duplicated, and 27 variations were formed: restorations made of IPS e.max, Vitablocs MarkII, and Vita Enamic, as well as different divergence angles of 6, 12, and 16 degrees prepared with 3 variations of pulp chamber floor designs, keeping the natural form, adding a 1-mm glass ionomer pulp chamber base, and adding a 2-mm extension into the distal canal. Stress distribution under axial loading and maximum von Mises stress values were analyzed and calculated by using the Ansys software program. ResultsThe endocrown restoration presented the lowest von Mises stress values when a 6-degree divergence angle was used with Vitablocs MarkII. However, in other layers such as enamel, resin cement, and pulpal floor, the lowest von Mises stress values were observed in IPS e.max restorative material when the divergence angle was increased to 16 degrees. No difference was found in the stress distribution pattern and maximum von Mises stress values in the alveolar bone or periodontal ligament. ConclusionsEndocrowns fabricated with lithium disilicate ceramics without intraradicular extension exhibited lower stresses on tooth structure. An increase in the divergence angle improved the stress distribution on tooth structure; however, sound dental tissue should not be removed to achieve better stress distribution.

Prevalence of Radix Entomolaris in Mandibular First Molars by Cone-Beam Computed Tomography in a Southern Chilean Sub-Population

The aim of this of this study was to evaluate the prevalence and morphology of radix entomolaris (RE) in the mandibular first molar (MFM) in a southern Chilean sub-population by cone-beam computed tomography (CBCT). Two hundred ten CBCT images of MFM were analysed. To detect the presence of RE, the observation and measurements were standardised, advancing 1 mm to apical from the floor of the pulp chamber to the most apical zone of the tooth. The data were analyzed using descriptive statistics, with a value of P < 0.05 being statistically significant. The prevalence of a third root in the permanent MFM was 5.7 % (12/210). The incidence of RE was the same in male patients (2.9 %) as in female patients (2.9 %) (p=0.324). The occurrence of an RE in the left MFM was 7.3 % (3/41 patients) for male patients and 4.5 % (3/66) for female patients (p=0.398). The right MFM in male patients had an incidence of 8.1 % (3/37) and 4.5 % (3/66) for female patients (p=0.340). When the presence of an RE was compared between the left (5.6 %) and right side (5.8 %), no statistically significant differences were found (p=0.998). The frequency of bilateral three-rooted MFM was 71.43 % (5/7) and 28.57 % (2/7) were unilateral. The prevalence of RE in MFM in a southern Chilean sub-population was 5.7 %. The occurrence was bilateral in the majority of cases and no significant differences were observed by sex or side. The commonest type of RE was Type 1 (83.3 %). The use of CBCT can improve the endodontic treatment outcome.

Pulp chamber floor anatomy of the maxillary first and second molars in an Indian population: A descriptive cross-sectional study using a new classification

Aim: The purpose of the present descriptive study was to evaluate and depict the form of the coronal pulp chamber floor in the permanent maxillary first (pMFM) and second (pMSM) molars in an Indian population. Subjects and Methods: Five hundred freshly extracted pMFM (n = 250) and pMSM (n = 250) were acquired from a pool of freshly extracted teeth unrelated to the current study. The crowns were flattened occlusally till the pulpal anatomy was seen and were photographed using a stereomicroscope at ×4.5 magnification. The number of orifices, shapes of the orifices, incidence of mesiobuccal 2 (MB-2), incidence of discobuccal 2 (DB-2), incidence of palatal 2 (P-2), shape of the access cavity, incidence and shape of isthmus, location of extra orifice, and the shape of the pulp chamber floor according to the Pawar and Singh classification© (K, Y, I, and others) were observed. Statistical Analysis: The level of significance for descriptive and frequency statistics was determined at 5%, with 95% confidence intervals. Results: Three root canal orifices occurred predominantly in 50.4% pMFM and 69.2% pMSM. The root canal orifices in the MB and distobuccal roots were round, whereas palatal orifices were oval. The access cavities were triangular in 51.6% pMFM, 51.2% pMSM, rhomboid shaped in 34.8% pMFM, 20.4% pMSM, and others in 13.6% pMFM and 28.4% pMSM. The extra orifices in pMFM were in MB in 20.8%, distobuccal in 14%, and palatal in 8% roots. For the pMSM, extra orifices were in MB (7.2%), distobuccal (6.4%), and palatal (2.4%) roots. The K, Y, I, and other classification were seen in 18.4%, 55.2%, 12.8%, and 13.6%, respectively, for pMFM and in 3.6%, 61.6%, 23.6%, and 11.6%, respectively, for pMSM. Conclusion: Our study investigated and described the various anatomical patterns of the coronal pulp chamber floor in maxillary molars. The classification applied to the patterns of the pulp chamber floor architecture can help clinicians determine the total number of canals as well as their unique orifice position and better communication.

Root and canal-specific features of maxillary first molars with fused roots

Background/Aim. Maxillary first molars are one of the most challenging teeth for endodontic therapy. There are certain disparities in the number of roots and canals and canal interrelationships within the same root, particularly those with fused roots. The aim of the study was to assess ex vivo features of roots, root canals, and canal walls in maxillary first molars with fused roots. Methods. Out of the total of 366 maxillary first molars, 64 extracted maxillary first molars with fused roots were included in the study using cone-beam computed tomographic and microscopic examining. Tooth dimensions at the level of pulp chamber floor, number, location and distance between orifices, number and canal morphology, canal wall thickness, and features of apical foramina were examined and measured. Results. The incidence of maxillary first molars with root fusion was 17.5%, of which 60.0% was palatal fused to distobuccal root. At the level of the pulp chamber floor, the bucco-palatal dimension was significantly larger at 10.4 mm than M-D with 7.0 mm. Four canal orifices were detected in 65.6%, with the shortest distance of 1.95 mm between MB1 and MB2. In fused roots, two or three canals most frequently correlated strongly with the number of major apical foramina. No fusion of canals was found in fused roots. The thinnest canal wall in the mesiobuccal and distobuccal fused root was mesial with 1.25 mm, and distal with 1.31 mm, while for the palatal root, the thinnest was the palatal wall with 1.97 mm. Two or three large apex foramina were registered with a significant correlation with the number of canals in the fused root. Conclusion. The most frequent type of fusion was between the palatal and distobuccal roots. Bucco-palatal dimension at the level of the pulp chamber floor was significantly larger than the mesiodistal, with the shortest inter-orifice distance between the MB1 and MB2 orifice. The number of canals was either two or three, coinciding with the number of major apical foramina. There was no fusion of the canals in fused roots. The thinnest canal wall was either mesial or distal.

Outcomes of furcal perforation management using Mineral Trioxide Aggregate and Biodentine: a systematic review

A comprehensive search was conducted using the PubMed database to identify experimental studies and case reports that describe treatment of furcal perforation. Studies and case reports that evaluated the outcome of repaired furcal perforations using MTA and Biodentine, published in English from 2018 to April 2022, were identified. Unavailable full texts were excluded. Initial screening of 724 articles (670 studies and 54 case reports). After discarding the duplicated studies, we reviewed 50 studies, selecting 13 for abstract analysis. We retrieved and evaluated full texts of eight studies and five case reports. Both materials had an equivalent success rate in the first three months but by 12 months Biodentine performed better than MTA clinically and radiographically. Repair of furcal perforation with Biodentine yields a better outcome compared to MTA.

Crystal Mush Growth and Collapse on a Steep Wall: The Marginal Border Series of the Skaergaard Intrusion, East Greenland

Abstract The Skaergaard Intrusion of East Greenland solidified as a closed system, with the development of progressively more fractionated material at the roof, floor and vertical walls of the magma chamber. We argue, using field observations of the exposed western margin together with detailed microstructural and geochemical analysis, that the mush on the vertical walls of the Skaergaard Intrusion reached a maximum thickness of ~180 m, and was highly unstable. Material was lost both continuously, due to non-retention of poorly consolidated material, and during episodic collapse events. The almost complete absence in the wall rocks of material formed in LZc times (following the saturation of the bulk magma in Fe-Ti oxides) was likely to have been caused by a collapse event, perhaps related to faulting of the actively extending Greenlandic margin. A second major collapse of the MBS occurred during the later stages of solidification, with the greatest loss of material occurring in a region of the wall with an unusually thick mush, creating a transient and localised increase in the thickness of the floor mush. This work demonstrates the importance of vertical walls in supplying loose, disaggregated material to form mobile magmatic slurries that may contribute to floor cumulates or be entrained and erupted in long-lived systems.

Interradicular Canals in 213 Mandibular and 235 Maxillary Molars by Means of Micro–computed Tomographic Analysis: An Ex Vivo Study

IntroductionBacteria and/or toxin residuals in the furcation areas of mandibular and maxillary molars can be the cause of persistent periapical tissue inflammation before or after an endodontic treatment. MethodsThe objective of this ex vivo study was to investigate the frequency of interradicular canals and diverticula in first and second mandibular and first and second maxillary molars by means of micro–computed tomographic imaging. Five hundred thirteen extracted molars, 211 mandibular molars and 302 maxillary molars, were included in this investigation. The area between the pulp chamber floor (PCF) and the furcation area was examined, and the data obtained were evaluated with imaging software that generated the corresponding 3-dimensional images. The results were analyzed by means of descriptive statistics. ResultsInterradicular canals were observed in 2.8% and 0.3% of the mandibular and maxillary molars, respectively. The diverticula (blind-ended interradicular canals) originated either at the furcation area or at the PCF. The diverticula frequency observed in mandibular molars was 3.3% (PCF) and 4.3% (bifurcation). The maxillary molar diverticula frequency observed was 2.0% (trifurcation), with none of them originating at the PCF. Altogether (n = 513) diverticula originated more frequently from the PCF (59.1%) than from the furcation area (40.9%). ConclusionsAlthough interradicular canals as well as diverticula were observed in a relatively small number of the investigated molars, practitioners should always be aware of their existence because without an adequate chemical debridement/disinfection of the pulp chamber root canal system, successful endodontic treatment could be compromised in up to 10% of the cases.

Transgressive nature and chilled margins of the Upper Zone in the western Bushveld Complex, South Africa

ABSTRACT The Upper Zone of the Bushveld Complex has long been known to have formed from a major influx of magma into the chamber that caused large-scale erosion of the chamber floor cumulates. The most dramatic manifestations of this process are two major gap areas (Northern and Southern) in the western Bushveld Complex in which the Upper Zone appears to have eroded away the underlying cumulates down to the very base of the Complex. However, due to almost complete lack of outcrops in the gap areas, no direct field observations have ever been reported to confirm the transgressive nature of the Upper Zone. Here, we present for the first time such observations from the Kameelhoek chromite mine located at the margin of the Northern Gap. In the open pit we have documented several transgressive depressions (up to 40 m in width) in the orthopyroxenite and chromitites of the Lower Critical Zone that are filled in with magnetite gabbro of the Upper Zone. The magnetite gabbro is chilled against the sidewalls of the depressions, forming glassy and fine-grained textured rocks with plagioclase laths arranged in radial clusters. Mineralogically and chemically, the magnetite gabbro correlates with cumulates from the lowermost part of the Upper Zone at its normal position in the complex. Three major points that have emerged from this study are: (1) the Critical Zone has been eroded away by magma that was parental to the Upper Zone, (2) this eroding magma was not the one that initiated formation of the Pyroxenite Marker, but rather the evolved melt that replenished the chamber at some later stage, and (3) the melt was phenocryst-free and likely derived from a deep-seated staging chamber. Our study thus supports a recent notion that even during the formation of the Upper Zone, the Bushveld chamber had still been operating as an open system that was replenished by melts from deeper magma sources.

Mapping of UV-C dose and SARS-CoV-2 viral inactivation across N95 respirators during decontamination

During public health crises like the COVID-19 pandemic, ultraviolet-C (UV-C) decontamination of N95 respirators for emergency reuse has been implemented to mitigate shortages. Pathogen photoinactivation efficacy depends critically on UV-C dose, which is distance- and angle-dependent and thus varies substantially across N95 surfaces within a decontamination system. Due to nonuniform and system-dependent UV-C dose distributions, characterizing UV-C dose and resulting pathogen inactivation with sufficient spatial resolution on-N95 is key to designing and validating UV-C decontamination protocols. However, robust quantification of UV-C dose across N95 facepieces presents challenges, as few UV-C measurement tools have sufficient (1) small, flexible form factor, and (2) angular response. To address this gap, we combine optical modeling and quantitative photochromic indicator (PCI) dosimetry with viral inactivation assays to generate high-resolution maps of “on-N95” UV-C dose and concomitant SARS-CoV-2 viral inactivation across N95 facepieces within a commercial decontamination chamber. Using modeling to rapidly identify on-N95 locations of interest, in-situ measurements report a 17.4 ± 5.0-fold dose difference across N95 facepieces in the chamber, yielding 2.9 ± 0.2-log variation in SARS-CoV-2 inactivation. UV-C dose at several on-N95 locations was lower than the lowest-dose locations on the chamber floor, highlighting the importance of on-N95 dose validation. Overall, we integrate optical simulation with in-situ PCI dosimetry to relate UV-C dose and viral inactivation at specific on-N95 locations, establishing a versatile approach to characterize UV-C photoinactivation of pathogens contaminating complex substrates such as N95s.

Too large to be seen: Regional structures in Lower and Middle Group chromitites of the Bushveld Complex, South Africa

The Critical Zone of the Bushveld Complex contains thick and laterally extensive Lower, Middle and Upper Group chromitite layers (LG, MG & UG, respectively), which are exposed within many open pit and underground mines. Using field observations from these exposures throughout the Eastern and Western Lobes of the Bushveld Complex, we describe here the morphology and field relationships of the LG and MG chromitites on a regional scale. This is done to gain a new regional perspective on the formation of massive chromitites. Some prominent chromitite layers are traceable over long distances and may occur as one, two or three separate chromitite layers at different locations, with several changes in the number of layers and their thicknesses happening along a distance of a few kilometres. This can be best understood as a structure of regionally bifurcating chromitites, with small-scale bifurcation being visible even at the scale of individual outcrops. We have documented field evidence indicating magmatic erosion of the floor cumulates. Among them are large inclusions of orthopyroxenite in chromitite that are partly attached to the footwall rocks, suggesting that they are erosional remnants of these rocks. Two potholes, roughly circular depressions in the chamber floor, were also documented. They show transgressive relationships of chromitites with their footwall rocks, suggesting that magmatic erosion has occurred prior to chromitite deposition. We propose that the regionally bifurcating chromitites are best explained in the frame of the model involving erosion of the footwall rocks by chromite-only-saturated magma replenishing the evolving chamber. In this process, different locations may have experienced different degrees of magmatic erosion, causing part of the footwall, the entire footwall or even part of the underlying chromitite to have been removed. Upon cooling, the new magma would have deposited chromitite on the erosional surface. Depending on the degree of magmatic erosion, a few separate chromitite layers or a single chromitite layer would form from several influxes of fresh magma into the chamber.

Frequency of number of roots and root canals of maxillary first premolar teeth.

Objective: To determine the frequency of the number of roots and root canals in a sample of 250 extracted maxillary first premolar teeth of patients visiting Peshawar Dental College and Hospital Khyber Pakhtunkhwa. Study Design: Cross Sectional. Setting: Department of Oral Biology, Peshawar Dental College and Hospital Khyber Pakhtunkhwa. Period: April 2016 to December 2016. Material &amp; Methods: A total of 250 extracted human maxillary first premolars were collected from the Department of Oral &amp; Maxillofacial Surgery, Peshawar Dental College, and Hospital Khyber Pakhtunkhwa. All teeth were visually inspected to count the number of roots. Subsequently, the access cavity was prepared, and pulp extirpated from each tooth. Endodontic explorer was used to locating the canal orifice(s) at the pulp chamber floor. Later the root canal orifices were injected with India ink to stain the canals. After that roots of teeth were sectioned at different levels to note down the number of canals. Data were analyzed using SPSS version 19. The statistical significance of the variations from mean values was considered significant if the p-value was less than 0.05. Results: Out of 250 maxillary first premolar teeth, 44.8% had one root, 40.4% had two separate and 12.8% had two fused roots. Three roots were seen in 2.0% teeth. Two root canals were present in the vast majority (70.4%), whereas one and three root canals were seen in 27.6% and 2.0% teeth, respectively. The correlation between the number of roots and root canals of maxillary first premolar teeth was highly significant. Conclusions: There was a high frequency of maxillary first premolars with two roots and two root canals.

2D radiographs, cone-beam computed tomography and 3D CBCT-based planning software in access cavity preparation: A single blinded randomised controlled invitro study.

This study compared endodontic access cavities prepared by operators of different experience levels (students, general-practitioners and specialists), guided by periapical radiographs, cone-beam computed tomography (CBCT) or 3D CBCT-based planning software, with regards to tooth substance loss and preparation errors. Operators (n = 34) prepared endodontic access cavities in 306 three-dimensionally printed copies of human teeth with standardised anatomies. Access cavities were volumetrically assessed post-operative using digital scans, while preparation errors were evaluated with CBCT. Tooth substance loss was significantly influenced by the operator's experience, being highest with students', followed by general-practitioners and specialists (P < 0.05), with no significant association with the employed imaging/planning modality. Pulp chamber floor, iatrogenic perforations and incomplete pulpal roof removal were insignificant between operator groups or imaging/planning modalities. It can be concluded that irrespective of advancement in imaging/planning modalities the practitioner's experience level remains to be the decisive factor significantly influencing tooth substance loss during endodontic access cavity preparations.

Sealing ability of three different materials to repair furcation perforations using computerized fluid filtration method.

Background. The present study aimed to evaluate the sealing ability of three different calcium silicate-based materials in furcation perforations. Methods. Seventy-six human mandibular molar teeth were selected. Perforations were created in the center of the pulp chamber floor. The experimental teeth were randomly divided into three groups (n=22). Perforations were repaired with MTA Angelus, Endocem MTA, or EndoSequence BioCeramic Root Repair Material Fast Set Putty (BC-RRM Putty). Microleakage of the different repair materials to be tested was measured by computerized fluid filtration method at 24- and 72-hour intervals. Results. For each time interval, no statistically significant difference was observed between the groups. For Endocem MTA and BC-RRM Putty groups, the difference between the leakage values measured at both periods was not statistically significant (P > 0.05). However, there was a significant difference for the MTA Angelus group (P < 0.05). Conclusion. All the calcium silicate-based materials used in the present study showed similar performance in repairing furcation perforations at 24- and 72-hour intervals.

Vertical relationships between the divergence angle of maxillary molar roots and the maxillary sinus floor: A cone-beam computed tomography (CBCT) study

AimTo assess the relations between the divergence angle of the maxillary molar roots and their proximity to the maxillary sinus floor using CBCT. MethodThis study comprised CBCT scans of the maxilla, including at least the inferior one-third of the maxillary sinus and at least one molar present in any quadrant with complete eruption and root formation. Evaluation included the vertical relations between the maxillary molar root apices and the maxillary sinus floor (MSF), and the root divergence was measured from the root apices to the floor of the pulp chamber. The chi-square test was used for the associations between the study parameters. For the correlation between root divergence angles and MSF vertical relationship types, the Spearman test was used. A P-value < 0.05 was considered significant. ResultsA total of 100 scans were analyzed, including 316 permanent maxillary first and second molars. The MSF Type II vertical relationship was the most prevalent (39.6%), followed by Type I (31.3%). The highest divergence angle was found between the distobuccal and palatal roots (mean = 44.9 ± 10.5°). For the mesiobuccal-distobuccal angle groups, there were higher percentages of the MSF Type I and II relationships among the angle groups < 1° and 21-45°. For the mesiobuccal-palatal angle groups, a higher prevalence of the MSF Type II relationship was found in the <21⁰ and >45⁰ angle groups, and a higher prevalence of the Type I relationship was found in the 21-45⁰ angle group. For the distobuccal-palatal angle groups, higher percentages of the MSF Type II relationship were found in the three angle groups. For all teeth, there was a significant positive correlation between the MSF vertical relationship and the mesiobuccal-palatal angle (r = 0.116; P = 0.039). ConclusionThere was a positive correlation between the divergence angle of the roots and their vertical relationship with the MSF. Clinicians should assess the divergence between the roots before performing extraction or endodontic treatments.

Non-surgical management of maxillary first molars with five root canals

Aim: This case series reports the non-surgical management of five maxillary first molars with five root canals in different ethnic groups and geographic locations. Summary: Diagnosis and management of complex root canal anatomy, especially of the maxillary first molar, can be frustrating and challenging and also may increase the risk of failure if not managed with appropriate tools. In this case series the primary endodontic treatment of four, and a non-surgical retreatment of one maxillary first molar with five root canals treated by three different endodontists from India, Spain and Portugal has been described. None of the cases presented in the paper were performed without magnification and troughing of the pulp chamber floor using ultrasonic tips. Although, CBCT wasn’t used in all cases although it’s prudent use respecting the ALARA principle is highlighted in the paper. This paper also highlights the importance of anatomical variations in different ethnic groups with the maxillary first molar. Key learning points Operator should consider the ethnicity of the patient and thoroughly study pre-operative radiograph to carry out successful endodontic treatment. Use of magnification and ultrasonic tips is fundamental especially in treating unusual canal anatomies. The prudent use of CBCT should be performed respecting the ALARA principle in all given situations.