Endodontic Dentistry: Analysis of Dentinal Stress and Strain Development during Shaping of Curved Root Canals.

BACKGROUND: Endodontic shaping causes stress and strain in the root canal dentin. Dentin microcracks have the potential to be later followed by root fractures occurring under the occlusal load. The aim of our research was to theoretically determine the values of such dentinal states of stress and strain during the endodontic shaping of curved root canals using finite element analysis (FEA). METHODS: To highlight the stress concentrations in dentin, two geometric models were created considering the volume of the curved dental root and the contact between the endodontic file and the root canal walls. The application of forces with different values was simulated both on a uniform curved root canal and on a root canal with an apical third curvature of 25° as they would be applied during the preparation of a root canal. RESULTS: In the case of the first model, which was acted upon with a force of 5 N, the deformations of the root canal appeared along the entire working length, reaching the highest values in the apical third of the root, although there were no geometric changes in the shape of the root canal. Regarding the second root model, with an apical third curvature of 25°, although the applied force was 2 N, the deformations were accompanied by geometric changes in the shape of the root, especially in the upper part of the apical third. At a higher force of 7 N exerted on the endodontic file, the geometric shape changed, and the deformation reached extreme critical values. The resulting tensile stresses appearing in the experimental structure varied similarly to the deformations. CONCLUSIONS: Significant stress and strain can develop, especially in the apical third of curved root canals during their shaping, and the risk of cracks is higher for endodontically treated teeth presenting severe curvatures in the apical third of the root.

Dental pathologies of endodontic origin and subsequent bacterial involvement - a literature review.

Dental pathologies of endodontic origin are varied in nature, and include infectious and non-infectious causes. Through this review, we aim to provide a deeper understanding of the role of bacterial involvement and in the pathogenesis of endodontic pathologies, by reviewing the relevant literature on the most common bacterial species involved, and their capacity to organize as biofilms. Furthermore, we focus on the most important recent updates in the management of endodontic infections, from a multidisciplinary perspective.

Evaluation of the sealer/gutta-percha ratio on sets of root section surfaces of some extracted teeth sealed using the cold lateral condensation technique.

Canal filling must be well adapted to the walls of the root canal to prevent bacterial infiltration. Endodontic seals play an essential role in ensuring tightness, without which the canal filling would suffer infiltrations. This study aimed to evaluate the areas occupied by the two components of the canal filling, as well as the sealer/gutta-percha ratio in the root canals of the maxillary central incisors after their filling using the cold lateral condensation technique with gutta-percha. Thirty extracted upper central incisors were rotatably prepared with ProTaper Universal up to F3 and sealed using the cold lateral condensation technique with gutta-percha. After setting the sealer, the roots of the teeth were sectioned perpendicularly to 1 (L1), 3 (L3), 6 (L6), and 8 (L8) mm from the apex. The surface of the sections was analyzed with a Leica EZ4D stereomicroscope and photographed at two magnification orders: 10x and 25x. The areas corresponding to the gutta-percha, sealer, gaps, and root canal were expressed in pixels using the ImageJ software, version 1.50i. The difference in the representation of sealer areas, gutta-percha and voids was statistically significantly different for all four sections analyzed. The best adaptation of the canal obturation was observed in L1 and L3. The gutta-percha area was statistically significantly higher than that of the sealer for the L1, L3, and L6 levels, while the sealer/gutta-percha ratio recorded the lowest value at the L3 level (0, 30) and the highest at its L8 (0.70) level, without registering statistically significant differences regarding the area at the four analyzed levels. The voids were mostly absent or recorded a minimal percentage area (<1%). Cold lateral condensation of gutta-percha has led to a good adaptation of gutta-percha to the root canal wall, with a small amount of sealer, especially to the sections made at 3 mm from the apex. Given the limitations of this study, we noted that the voids were few - observed in the 6 and 8 mm sections - and were negligible in many cases.

Oral Health Related Quality of Life and Prosthetic Status among Institutionalized Elderly from the Bucharest Area: A Pilot Study.

The aim of the study was to assess the oral health related quality of life (OHRQoL) of elderly in care homes, one of Romania's most vulnerable social categories, to correlate it to sociodemographic, oral health parameters, and prosthodontic status. Therefore, a cross-sectional study was performed on 58 geriatrics divided into 3 age groups, who were clinically examined and answered the oral health impact profile (OHIP-14) questionnaire. Very high rates of complete edentulism in the oldest-old subgroup (bimaxillary in 64.3%; mandibular in 64.3%; maxillary in 85.7%), and alarming frequencies in the other subgroups (middle-old and youngest-old), statistically significant differences between age groups being determined. The OHIP-14 mean score was 14.5. Although not statistically significant, females had higher OHIP-14 scores, also middle-old with single maxillary arch, single mandibular arch, and bimaxillary complete edentulism, whether they wore dentures or not, but especially those without dental prosthetic treatment in the maxilla. A worse OHRQoL was also observed in wearers of bimaxillary complete dentures, in correlation with periodontal disease-related edentulism, in those with tertiary education degree, and those who came from rural areas. There were no statistically significant correlations of OHRQoL with age, total number of edentulous spaces or edentulous spaces with no prosthetic treatment. In conclusion, despite poor oral health and prosthetic status of the institutionalized elderly around Bucharest, the impact on their wellbeing is comparatively moderate.

Fracture resistance of endodontically treated teeth restored with resin post reinforced with glass fiber.

This study aims to determine whether the design of resin posts reinforced with glass fiber (FRC) and Reporfost (Angelus, Londrina, PR, Brazil) significantly improves the fracture resistance of endodontically treated teeth restored through this method.A batch of 30 maxillary monoradicular teeth (15 central incisors, 15 canines) were treated endodontically by step-back technique (apical enlargement 40-K file) sealed with Sealapex (Kerr Corporation, Orange, US) and gutta-percha by lateral condensation, cold. They were divided into two equal groups, prepared for cementing the FRC posts. The Exacto posts (Angelus, Londrina, PR, Brazil) in group 1 and the Reforpost posts (Angelus; Londrina; PR, Brazil) were cemented with dual cure resin cement Breeze Self-Adhesive Resin Cement (Pentron Clinical, Orange, US). Fracture resistance testing was performed on the crown-apical axial direction, using the Hounsfield / Tinius Olsen H1-KS, PA, USA mechanical testing apparatus. The behavior of each tooth-post assembly was recorded as a graph. The statistical analysis was done using one way ANOVA (α=0.05). The differences between the Exacto post group and the Reforpost post group are not statistically significant (p = 0.466). The maximum force recorded was 970 N and the minimum 186N. The mean force at which the fracture occurred was approximately 500N for both groups. The strain test showed that modifying the Reforpost post design did not improve the fracture resistance parameters of the tooth-post assembly through increasing the surface friction or maintaining adhesion to the walls of the root dentin.

Etiology and Prevention of an Endodontic Iatrogenic Event: Instrument Fracture.

Although benefiting from an unprecedented technological evolution, contemporary endodontics is still characterized by the recurrence of retreatments, due to the need to solve quite frequent incidents, accidents, or even failures of primary endodontic treatment. This survey aims to assess both the etiology and the prevention methods of one of the most troublesome endodontic iatrogenies: instrument separation during root canal shaping. The multifactorial nature of this occurrence entails identifying and taking into account all the causal and contributing factors. Their significant number and the possible involvement of any of them, starting with the complexity and variability of the root canals and ending with the technical specifications concerning the nickel-titanium rotary instrumentation system being used, highlight the necessity to develop valid guidelines to avert the occurring of such an upsetting situation.

Performance Evaluation on Rotary Preparation of Root Canal by Beginner Operators.

This study aims to analyze the performance of rotary root canal preparation, conducted by beginner operators (students). After acquiring the necessary skills involved in applying endodontic preparation techniques on extracted teeth, all students from a cohort learned to use ProTaper Universal files (Dentsply Maillefer). The preclinical training had several stages. Experience 1: instrumentation on extracted single-root teeth; Experience 2: instrumentation on EndoTraining blocks (Dentsply Maillefer); Experience 3: instrumentation on EndoTraining blocks (Dia Dent Group International); Experience 4: Instrumentation on extracted multiradicular teeth. Preparation was done according to the manufacturer's instructions, the initial file is Sx, followed by S1, S2, F1, F2 and the last file is F3. A batch of 50 teeth (E1, E2, E3, E4) was randomly selected to evaluate the onset of the rotary preparation of young operators. Two independent evaluators analyzed the array radiologically by stereomicroscope evaluation (E1, E4) and photo-analysis of the resulting Endo Training blocks (E2, E3). The success rate was 80% for E1, 72% for E2, 64% for E3 and 76% for E4 (p<0.05). The following were considered a failure: ledge formation and apical transportation in 10.66%, over instrumentation in 6.66%, zipping in 3.33%, and instrument fracture in 4% of cases. Endodontic instrumentation techniques require training to acquire the necessary skills. Rotary root canal instrumentation techniques used almost exclusively in modern endodontics require adequate preclinical training.

Stereomicroscopic and Microscopic Study of Dental Structural Aspects Derived from Iatrogenic and Pathological Processes Suffered by a Second Mandibular Premolar - A Case Study.

Microscopic studies performed on extracted human teeth after their preparation in advance is helpful in a relatively good reestablishment of the treatment steps that have been applied to these teeth, as well as an evaluation of the quality of such treatments. Therefore, we have used stereo- and optical microscopy, highlighting aspects of external morphology, as well as root canal space of an extracted mandibular second premolar, subjected to prosthetic and endodontic treatment. In order to verify some technical errors that might occur during the endodontic and restorative treatment, we tried to appreciate the quality of the root canal filling and cervical defect and access cavity restoration of an extracted premolar #45.Without having the data from clinical records, we concluded that the method used for root canal filling was the warm lateral condensation technic; we also appreciated the quality of the fusion of the gutta-percha cones used, so the introduction of heated spreaders only in the central part of the bunch of cones makes it possible to clearly detect the boundaries between these cones towards the outside of the filling.

Hemobilia by idiopathic aneurysm of cystic artery, fistulized in the biliary ways - clinical case.

Aneurysm of the cystic artery is not common, and it is a rare cause of hemobilia. Most of reported cases are pseudoaneurysms resulting from either an inflammatory process in the abdomen or abdominal trauma. We report a healthy individual who developed hemobilia associated with cystic artery aneurysm. Visceral artery aneurysms are rare and can rupture with potentially grave outcome due to excessive bleeding. The patient was managed with cholecystectomy and concomitant aneurysm repair.

An application of microscopic investigation on extracted premolar with dyschromia, related to the components of endodontic sealer.

The aim of this study was an assessment of the overall optical characteristics changes in volume of the dentin, after the diffusion of the chemical components included in the sealer throughout the endodontic space, in order to demonstrate the discoloration effect of the endodontic sealer on tooth crown of a recently extracted maxillary premolar. Thin sections were studied using the polarized transmitted light microscopy and under a stereomicroscope, operating in transmitted light and reflected light. There were performed serial images of magnitude 40×. Each image was covered by a grid aimed for microscopic sections volumetric measurements. Therefore, all the serial images were merged and resulted a global image of the entire section surface. Thus, we have analyzed a total of three sections of the same tooth. Based on these sets of images, there were made estimations of the areas affected by colorations, determinations that can be extrapolated to total tooth areas, in terms of volumetric color change of dentin. The proportion of low coloristic infiltrated dentin was very close to the deeply impregnated dentin and the overall impregnated dentin covered half of the total dentin analyzed area.

[Multidisciplinary approach in pyomyositis early diagnosis]. / Abordare multidisciplinara în diagnosticul precoce al piomiozitei.

Pyomyositis is a disease characterized by primary bacterial infection of the skeletal muscles of lower limbs and thorax. It is a very rare disease (100 cases in USA in the last 20 years) but with an increasing occurrence especially among patients with AIDS in an advanced stage or in association with other pathologic conditions like diabetes mellitus, cancer, connective tissue diseases or hematological disorders, long usage of corticosteroid drugs. We are hereby showing the case of a 46-year-old female who presented difficult problems of differential diagnosis until final diagnosis was established. Her life was saved due to an exemplary interdisciplinary collaboration and by using an extremely useful imaging method for musculoskeletal pathology--IRM. The IRM protocol: coronal and axial T2 weighted SE, coronal and axial T1 weighted SE, axial and coronal T2 weighted + Fat Sat was comprehensive and conclusive. The imaging diagnosis established the presence and extension of the muscle abscess, leading to an efficient drainage. After the surgery, the repeated IRM confirmed the drainage efficiency. Unlike the French literature which claims that the muscle abscesses are secondary to a primary center, in this case, and in accordance with Anglo-Saxon literature, the muscle abscess was primary, in absence of any other center of infection.