Efficacy of WaveOne Gold and ProDesign RT systems in removing filling material: a micro-CT analysis.

The remaining filling material after retreatment can harbor bacteria and organic tissues that can influence the outcome of the therapy. AIM: The aim of this study was to evalúate, by micro-CT, the amount of filling material remaining in the root canal after its removal using WaveOne Gold or ProDesign RT. MATERIAL AND METHOD: Forty human mandibular canines were instrumented with the ProTaper Next system up to the X2 instrument (25.06) and filled with gutta-percha cones and AHPlus. Teeth were divided into 2 groups (n=20): WaveOne Gold 25.07 (WOG) and ProDesign RT 25.08 (PRT) for filling removal, after which they were scanned in a micro-CT device to quantify the volume of remaining filling material. The data were subjected to log 10 transformation, Student 's t-test was performed to account for multiple observationsper sample, significance was set at 5%. RESULTS: Student 's t-test showed that there was no difference between the two systems regarding the volume of remaining filling material in the thirds: apical (p = 0.392), middle (p = 0.065), or cervical (p = 0.918). CONCLUSIÓN: Remaining filling material was present in all groups and both systems were similar in removing root filling material in mandibular canines.

A permanencia de material obturador após o retratamento pode abrigar bactérias e tecidos orgánicos que podem influenciar o resultado da terapia. OBJETIVO: O objetivo deste estudo foi avaliar, por micro-CT, a quantidade de material obturador remanescente no canal radicular após a desobturagdo com WaveOne Gold e ProDesign RT. MATERIAL E MÉTODO: Quarenta caninos inferiores humanos foram instrumentados com o sistema ProTaper Next até o instrumento X2 (25.06) e obturados com cones de guta-percha e AHPlus. Os dentes foram divididos em dois grupos (n=20): WaveOne Gold 25.07 (WOG) e ProDesign RT 25.08 (PRT) e escaneados em micro-CT para quantificagdo do volume de material obturador remanescente. Os dados foram submetidos á transformando log 10, o teste t de Student foi realizado para contabilizar múltiplas observagoes por amostra, a significáncia foi fixada em 5%. RESULTADOS: O teste t de Student mostrou que ndo houve diferenga no volume de material obturador remanescente entre os dois sistemas nos tergos: apical (p = 0,392), médio (p = 0,065) ou cervical (p = 0,918). CONCLUSÃO: O material obturador remanescente estavapresente em todos os grupos e ambos os sistemas foram semelhantes na remogdo do material obturador radicular nos caninos inferiores.

Frequency of root resorption following trauma to permanent teeth.

This retrospective study evaluated the frequency of development of root resorption in dental trauma cases involving supporting tissue. For 249 traumatized teeth of 125 patients aged between 7 and 51 years, we collected data on the gender and age of the patient, the teeth involved, the type of trauma, and the period between dental injury and initial examination. Radiographic parameters examined in relation to root resorption included the presence of inflammatory external root resorption, internal root resorption, replacement resorption, and canal calcification. Data were analyzed by chi-squared test, Fisher's exact test, and mult iple logistic regression (P < 0.05). The results indicated that there was a significant relationship between the period from the date of injury until initial examination and the occurrence of inflammatory external resorption (P = 0.0199), as well as the type of injury (P = 0.0406). Furthermore, external resorption was most frequently associated with intrusive luxation (92.8%), followed by avulsion (89.0%), lateral luxation (80.2%), and extrusive luxation (77.4%). Among the types of dental injury, replacement resorption was observed more frequently in cases of avulsion (87.2%). The only factor that was significantly associated with this type of resorption was the type of injury (P < 0.0001). Root resorption is observed more frequently and its risk of development is higher in cases of severe trauma, especially avulsion and intrusive luxation.

Repair of apical root resorption associated with periodontitis using a new intracanal medicament protocol.

Endodontic therapy is indicated for cases of traumatic tooth dislocation associated with pulp necrosis and/or inflammatory resorption. Here we describe the management of a maxillary left lateral permanent incisor that suffered lateral luxation, leading to pulp necrosis and root resorption, in a 13-year-old boy. The traumatized tooth was treated successfully by intracanal medication with calcium hydroxide, 2% chlorhexidine gel and zinc oxide for 12 months without any need to change the dressing, followed by conventional root canal filling. The postoperative course was uneventful and a stable clinical outcome was obtained with evidence of periapical lesion repair and stabilization of the resorption process.

Microbial evaluation of traumatized teeth treated with triple antibiotic paste or calcium hydroxide with 2% chlorhexidine gel in pulp revascularization.

INTRODUCTION: Revascularization outcome depends on microbial elimination because apical repair will not happen in the presence of infected tissues. This study evaluated the microbial composition of traumatized immature teeth and assessed their reduction during different stages of the revascularization procedures performed with 2 intracanal medicaments. METHODS: Fifteen patients (7-17 years old) with immature teeth were submitted to the revascularization procedures; they were divided into 2 groups according to the intracanal medicament used: TAP group (n = 7), medicated with a triple antibiotic paste, and CHP group (n = 8), dressed with calcium hydroxide + 2% chlorhexidine gel. Samples were taken before any treatment (S1), after irrigation with 6% NaOCl (S2), after irrigation with 2% chlorhexidine (S3), after intracanal dressing (S4), and after 17% EDTA irrigation (S5). Cultivable bacteria recovered from the 5 stages were counted and identified by means of polymerase chain reaction assay (16S rRNA). RESULTS: Both groups had colony-forming unit counts significantly reduced after S2 (P < .05); however, no significant difference was found between the irrigants (S2 and S3, P = .99). No difference in bacteria counts was found between the intracanal medicaments used (P = .95). The most prevalent bacteria detected were Actinomyces naeslundii (66.67%), followed by Porphyromonas endodontalis, Parvimonas micra, and Fusobacterium nucleatum, which were detected in 33.34% of the root canals. An average of 2.13 species per canal was found, and no statistical correlation was observed between bacterial species and clinical/radiographic features. CONCLUSIONS: The microbial profile of infected immature teeth is similar to that of primarily infected permanent teeth. The greatest bacterial reduction was promoted by the irrigation solutions. The revascularization protocols that used the tested intracanal medicaments were efficient in reducing viable bacteria in necrotic immature teeth.

Relation between postexercise abnormal heart rate recovery and myocardial damage evidenced by gated single-photon emission computed tomography.

Abnormal heart rate recovery (HRR) after exercise has been associated with increased cardiac mortality. The ability of gated myocardial perfusion single-photon emission computed tomography (SPECT) to evaluate myocardial perfusion and function simultaneously might make it helpful in determining possible mechanisms that are involved in this finding. This study investigated the association between abnormal HRR and other indicators of risk for cardiovascular events. Patients (n = 1,296, 784 men; 57 +/- 11 years of age) who underwent exercise/technetium-99m sestamibi gated myocardial perfusion SPECT at rest were prospectively enrolled. Exercise treadmill testing was performed according to a symptom-limited Bruce's protocol. HRR was obtained from the subtraction of heart rate in the first minute of recovery after exercise treadmill testing from maximal heart rate during exercise. Myocardial perfusion SPECT was semi-quantitatively analyzed using a 17-segment left ventricular model. Left ventricular ejection fraction was automatically calculated using quantitative gated SPECT software. In our study, patients with abnormal HRR were older, more frequently diabetic, and hypertensive and had previous myocardial infarction and myocardial revascularization, higher heart rate at rest and perfusion defect quantification scores, lower left ventricular ejection fraction, and larger left ventricular volumes than did patients with normal HRR. In multivariable analysis, age (p <0.0001), heart rate at rest (p <0.0001), left ventricular ejection fraction (p <0.0001), and perfusion defect extent and severity at rest (p = 0.038) were independent predictors of abnormal HRR. In conclusion, abnormal HRR was significantly associated with lower left ventricular ejection fraction and with perfusion defect extent and severity at rest, but not with gated SPECT markers of myocardial ischemia. Therefore, abnormal HRR may reflect myocardial damage.