Root canal curvature influences uncontrolled removal of dentin and cleaning efficacy after ultrasonic activation

Abstract This study evaluated the correlation between root canal curvature and the effects of ultrasonic irrigation in the following parameters: volume of uncontrolled dentin removal (UDRVol), maximum depth of dentin defects, removal of accumulated hard tissue debris (AHTD), and canal transportation in prepared curved root canals. Twenty-four human permanent mandibular molars were divided into two groups according to root canal curvature: moderate curvature (MC: mean 25°); and severe curvature (SC: mean 48°). The specimens were scanned using an X-ray microcomputed scanner (Skyscan 1172) before and after cleaning and shaping and after the final irrigation protocol with ultrasonic irrigation. There was a moderate correlation between the degree of root canal curvature and the volume of remaining AHTD (p<0.05) and between the degree of root canal curvature and maximum depth of defects due to uncontrolled removal of dentin (p<0.05). The teeth in the SC group had a greater maximum depth of defects on the dentin wall in the apical third than the teeth in the MC group (p <0.05). Both groups had a significant reduction of AHTD in all canal thirds, but the amount of remaining AHTD in the middle and apical thirds and the whole canal was significantly greater in the SC than in the MC group (p <0.05). Canal transportation was not influenced by the canal curvature in all thirds (p >0.05). This study concluded that root canal curvature affects significantly the uncontrolled removal of dentin and remaining AHTD volume after the final irrigation protocol with ultrasonic irrigation.

Resumo Este estudo avaliou a correlação entre a curvatura do canal radicular e os efeitos da irrigação ultrassônica nos seguintes parâmetros: volume de remoção não controlada de dentina (UDRVol), profundidade máxima do desgaste de dentina, remoção de debris de tecido duro acumulado (AHTD) e transporte em canais radiculares curvos. Vinte e quatro molares inferiores humanos permanentes foram divididos em dois grupos de acordo com a curvatura do canal radicular: curvatura moderada (MC: média de 25°); e curvatura acentuada (SC: média de 48°). Os espécimes foram digitalizados usando um scanner microcomputador de raios X (Skyscan 1172) antes e depois da limpeza e modelagem e após a irrigação ultrassônica. Houve uma correlação moderada entre o grau de curvatura do canal radicular e o volume de AHTD remanescente (p<0,05) e entre o grau de curvatura do canal radicular e a profundidade máxima de defeitos devido à remoção descontrolada de dentina (p<0,05). Os dentes do grupo SC apresentaram maior profundidade máxima de defeitos na parede dentinária no terço apical do que os dentes do grupo MC (p<0,05). Ambos os grupos tiveram uma redução significativa de AHTD em todos os terços do canal, mas a quantidade de AHTD remanescente nos terços médio e apical e em todo o canal foi significativamente maior no grupo SC do que no grupo MC (p <0,05). O transporte do canal não foi influenciado pela curvatura do canal em todos os terços (p > 0,05). Este estudo concluiu que a curvatura do canal radicular afeta significativamente a remoção descontrolada de dentina e o volume remanescente de AHTD após a irrigação ultrassônica.

Evaluation of 3D-Printed Dog Teeth for Pre-clinical Training of Endodontic Therapy in Veterinary Dentistry.

Artificial teeth in dental training have become a valuable tool for students to gain hands-on experience in a safe and controlled environment. This training method allows students to practice various dental procedures and develop their skills without putting patients at risk. Artificial teeth can be used to simulate dental conditions, allowing students to gain experience in dealing with various situations and techniques. Although previous studies in human dentistry have demonstrated the feasibility of using 3D-printed teeth for teaching endodontic procedures such as root canal therapy, similar research has yet to be conducted in the veterinary field. This study aimed to assess the feasibility of creating 3D-printed teeth from an adult dog skull and validate their use as an alternative training tool for root canal therapy in this species. For this, cone beam computed tomography images from a medium-sized dog skull were used to replicate its teeth using a digital 3D printing system. Then, artificial mandibular first molar teeth and a 24-question survey were sent to specialized veterinary dentistry practitioners in Brazil to assess their perception of the model's characteristics during endodontic treatment. In conclusion, it was feasible to create 3D-printed models of dog teeth with high accuracy for the endodontic system. Despite the differences in the properties of the two materials between natural and artificial teeth, it was possible to use the artificial tooth as a training device for conventional endodontic treatment in dogs. The reliability level for the survey was reported as good, displaying a reliability coefficient above 0.86.

Influence of age and experience with magnification on locating the second mesiobuccal canal in maxillary first molars: A preliminary study.

The aim was to evaluate the effectiveness of clinical methods in identifying the presence of second mesiobuccal canal in maxillary first molars. The influence of age and experience with microscopy was also assessed. Sixty six teeth were selected and the mesiobuccal canal was confirmed in all of the samples by Cone-Beam Computed Tomography. After endodontic cavity access, teeth were evaluated through direct visual; dental loupe and operating microscope. None of the methods was successful in finding the mesiobuccal canal in all samples. Professionals <40, the magnification did not influence the location. Professionals >40, the magnification significantly influenced the location. In the direct vision, professionals >40 years located fewer canals than those <40 years of age with experience. In conclusion, these preliminary findings showed that when the microscope was used, the professionals with experience, regardless of age, found a higher number of canals. The use of the microscope was significant for professionals >40 years.

Regenerative Endodontic Therapy for Management of an Immature Permanent Tooth with Recurrent Post-treatment Apical Periodontitis: A Case Report.

This case report describes the treatment outcome and further retreatment of an immature permanent maxillary right central incisor with necrotic pulp and chronic apical abscess using regenerative endodontic therapy (RET). The patient had a history of traumatic injury. The initial periapical radiographic and cone-beam computed tomographic (CBCT) examinations revealed tooth #8 had incomplete root formation, thin dentinal walls, and pulp necrosis associated with a large apical periodontitis lesion. RET was conducted in two visits and included a disinfection protocol with 5.25% NaOCl irrigation and medication with a double antibiotic paste (metronidazole and ciprofloxacin). At the second visit, a blood clot was induced, and the cervical third was sealed with a mineral trioxide aggregate plug and the coronal portion with light-cure composite. The tooth was asymptomatic at the 12-, 24-, and 36-month follow-ups, and radiographs showed continued root development with healed periradicular tissues. However, the 4-year radiographic follow-up revealed a recurrent apical periodontitis lesion. A second attempt of RET was conducted in one visit using 1% NaOCl irrigation and stimulation of a blood clot. A double seal with silicate-based cement and composite was placed. At the 24-month follow-up, the tooth remained asymptomatic, and both radiographic and CBCT examinations showed apical closure and complete repair of the periradicular tissues. When a tooth develops recurrent apical periodontitis, a second attempt of RET is a feasible option to control infection, helping to promote tooth retention associated with healthy periradicular conditions.

Cavernous sinus thrombosis followed by brain ischaemia in a type-1 diabetic patient: a persistent endodontic infection report.

Central nervous system infections and cavernous sinus thrombosis are associated with high mortality rates and may be a consequence of oral infection propagation. A 24-year-old woman has attended a private dental office with a pain complaint in the upper right central incisor and had the endodontic treatment completed. However, the patient returned to the dental office reporting pain in the same tooth and the presence of swelling. Then, the root canal was retreated. After one week, the patient presented to a Basic Health Unit with a history of vomiting and convulsion crisis followed by loss of consciousness. A computed tomography exam showed cavernous sinus thrombosis and brain ischaemic areas. The present report describes a rare case of cavernous sinus thrombosis followed by brain ischaemia in a type-1 diabetic patient, associated with persistent endodontic infection, with subsequent patient's death.

Aspectos de interesse das reabsorções cervicais invasivas: uma revisão da literatura / Aspects of interest in invasive cervical resorptions: a literature review

A reabsorção cervical invasiva (RCI) é um processo patológico e agressivo formado a partir de ações de células clásticas que provocam destruição da estrutura dental. Caracteriza-se pela invasão de tecido fibrovascular e fibro-ósseo na região cervical da raiz, reabsorvendo cemento, esmalte e dentina. A etiologia da RCI ainda não foi bem elucidada, mas já se sabe que seu início depende da lesão ou deficiência da camada de cemento na região cervical da raiz, na região correspondente a junção amelocementária. Vários fatores predisponentes já foram identificados como: tratamento ortodôntico, clareamento endógeno e trauma. Na maioria dos casos, a reabsorção é assintomática. Apresenta poucos sinais e sintomas clínicos, e sua identificação é comumente realizada através de exames radiográficos de rotina. Uma vez identificada, a tomografia computadorizada de feixe cônico é um exame essencial para o correto planejamento de condução do tratamento, devido ao fato de ser possível observar toda extensão da lesão, identificar a natureza do processo e localizar o portal de entrada da lesão. Existem vários tipos de tratamento, como extrusão do elemento dentário para exposição da região de reabsorção futura restauração com material biocompativel, exposição cirúrgica com retalho ou até mesmo exodontia nos casos mais graves. Quanto mais precoce for o diagnóstico maiores são as taxas de sucesso.

Invasive cervical resorption (ICR) is a pathological and aggressive process formed from the actions of clastic cells that cause destruction of the dental structure. It is characterized by the invasion of fibrovascular and fibro-osseous tissue in the cervical region of the root, resorbing cement, enamel and dentin. The etiology of ICR has not yet been well elucidated, but it is already known that its onset depends on the lesion or deficiency of the cementum layer in the cervical region of the root, in the region corresponding to the cementoenamel junction. Several predisposing factors have already been identified, such as orthodontic treatment, endogenous bleaching and trauma. In most cases, resorption is asymptomatic. It presents few clinical signs and symptoms, and its identification is commonly performed through routine radiographic examinations. Once identified, cone beam computed tomography is an essential exam for the correct planning of treatment, due to the fact that it is possible to observe the entire extension of the lesion, identify the nature of the process and locate the entrance portal of the lesion. There are several types of treatment, such as extrusion of the dental element to expose the resorption region for future restoration with biocompatible material, surgical exposure with a flap or even extraction in the most severe cases. The earlier the diagnosis, the higher the success rates.

Antibacterial efficacy and discolouration potential of antibiotic pastes with macrogol for regenerative endodontic therapy.

This study aimed to evaluate the antibacterial efficacy and discolouration potential of antibiotic pastes containing macrogol. Seventy single-rooted teeth were contaminated with a culture of Enterococcus faecalis for 30 days. Double (DAP) and triple antibiotic pastes (TAP) containing propylene glycol or macrogol as vehicles were applied. After 15 days, bacterial viability was compared. Change in teeth coronal colour was measured by a spectrophotometer. Statistical analysis was performed using anova and Tukey's test (P < 0.05). TAP containing clindamycin and propylene glycol was the only medicament that led to the presence of contamination, while the same combination of antibiotics containing macrogol did not result in bacterial growth (P < 0.05). Only the pastes containing minocycline in formulation resulted in coronal discolouration (P < 0.05). Both DAPs evaluated and the TAP containing clindamycin and macrogol showed to be the preferable options for regenerative endodontic therapy, as they were effective against E. faecalis biofilm and did not promote tooth discolouration.

Combined Endodontic and Surgical Therapy for Resolution of Type III Dens Invaginatus.

Dens invaginatus is an abnormal dental developmental, probably resulting of the invagination of mineralized tissues from the tooth crown surface before its calcification. The teeth that are most affected by this abnormality are the maxillary lateral incisors. This dental developmental anomaly has various types and the rarest is type III which has the worst prognosis, because of its complex anatomy. Conventional root canal therapy may not sufficiently resolve the case itself and in some circumstances the surgical intervention is also necessary. This report addresses a complex combined endodontic treatment of a type III dens invaginatus in a maxillary lateral incisor in an 18 years-old female patient, with an extensive periapical lesion affecting the buccal and palatine cortical bone, diagnosed by cone-beam computed tomography (CBCT). The case was conducted with the combination of endodontic and surgical treatment, under the use of the surgical operating microscope. The association of CBCT, visual magnification, XP-endo Finisher, bioceramic sealer, MTA Repair HP and bone graft were important to ensure predictable success.

Ability of two single-step restorative materials to avoid crown darkening caused by intracanal minocycline paste.

OBJECTIVES: This study aimed to quantitatively assess the ability of two single-step restorative materials to avoid crown darkening caused by the use of minocycline as an intracanal medicament. MATERIALS AND METHODS: After coronal access and instrumentation, 120 maxillary incisors were divided into four groups (n = 30). Two experimental groups according to the restorative material applied to the inner walls of the access cavity: OB, OptiBond All-In-One + minocycline intracanal paste; U200, RelyX U200 + minocycline intracanal paste. Two control groups without restorative materials: MIN, minocycline intracanal paste and SL, saline intracanal. Color determination was performed using a spectrophotometer at five time points, immediately after materials were applied (baseline), and at 7, 14, 21, and 28 days from the baseline. RESULTS: Decrease in the mean values of L* (luminosity) was observed after insertion of minocycline paste in all groups at all time points. Statistically significant differences were absent between the time points (P > .05). After 28 days, MIN showed significantly more darkening (ΔL*) (- 10.6 ± 7.3) than OB (- 5.4 ± 6.2), U200 (- 5.8 ± 3.9) and SL (- 2.3 ± 1.2) (P < .05). CONCLUSIONS: Crown darkening can be minimized by the previous application of RelyX U200 or OptiBond All-In-One to the inner walls of the access cavity before a minocycline-containing paste is applied as an intracanal medication. CLINICAL RELEVANCE: The American Association of Endodontists Clinical Considerations for Regenerative Procedures in necrotic immature teeth suggests the triple antibiotic paste as an intracanal medication (2018). However, discoloration and crown darkening are common unfavorable outcomes. The clinical protocol suggested in this paper has shown to be able to minimize crown darkening, predictably leading to a better patient-centered clinical success.

Diferencia entre las medidas radiográficas y anatómicas de conductos, posterior a la preparación para la colocación de postes / Difference between radiographic and anatomical measurements of canals, after preparation for the placement of a post

Antecedentes: Las radiografías periapicales presentan distorsiones que podrían conducir a un mayor desgaste de la estructura dental aumentando el riesgo de debilitamiento y de perforación o fractura vertical cuando se realiza la preparación del conducto radicular para la colocación de postes. Objetivo: El objetivo de la presente investigación es determinar la diferencia entre las medidas del espesor radiográfi co y el espesor anatómico mediante un calibrador de la dentina residual, luego de la preparación para poste en conductos ovales de premolares. Material y métodos: 50 premolares fueron tratados endodóncicamente y posteriormente fueron desobturados con fresas Pesso #1 y 2 dejando 4 mm de sellado apical, se realizó la toma radiográfi ca y se comparó con medidas realizadas con un calibrador digital. Las medidas fueron comparadas con una t de Student. Resultados: Las medidas radiográfi cas fueron 24.63% más grandes en comparación con las medidas del calibrador. Las medidas radiográfi cas no fueron signifi cativamente mayores en comparación con las del calibrador digital. Conclusiones: La radiografía periapical presenta una sobrestimación de la medida de la dentina residual, por lo tanto se debe escoger el protocolo más conservador para obtener resultados predecibles y exitosos (AU)

Background: Periapical radiographs have distortions that lead to greater wear of the dental structure, increasing the risk of weakening, perforation or vertical fracture when the root canal is preparation for post placement. Objective: The investigation is to determine the diff erence between the measurements of the radiographic thickness and the anatomical thickness by means of a calibrator of the residual dentine after the preparation for post placement. Material and methods: Root canal treatment was performed in 50 premolars and was unsealed with Pesso #1 and 2 leaving 4 mm of the apical seal, the radiographic was made and compared with measurements made with a digital calibrator. The measurements were compared with a Student t. Results: The radiographic measurements were 24.63% larger than the caliper measurements. The radiographic measurements were signifi cantly higher in comparison with the digital calibrators. Conclusions: The periapical radiography presents an overestimation residual dentin measurement, therefore the most conservative protocol should be chosen to obtain predictable and successful results (AU)

Application of forensic luminol for blood detection in endodontic files / Aplicação do luminol forense para detecção de sangue em limas endodônticas

Introduction: Blood is a biological material with high potential of infectious transmission in dental environments, including herpes simplex, hepatitis and AIDS. Aim: To investigate the efficacy of luminol in detecting blood in endodontic files before and after the sterilization process. Material and method: Luminol was used to investigate the presence or absence of traces of blood tissue in 50 endodontic files, visible to naked eye or not, after performing endodontic treatment and after the cleaning/sterilization process. The results obtained were tabulated and statistically analyzed by using the Friedman's test at a significance level of 5% (p<0.05). Result: By naked eye, it was found that 31/50 files showed no trace of blood, 8/50 showed a slight presence of blood and 11/50 showed a considerable presence of blood after endodontic treatment. After the use of luminol, however, 16/50 endodontic files showed no trace of blood, 19/50 showed a slight presence of blood and 15/50 showed a considerable presence of blood. After the cleaning and sterilization process, no blood was detected in the files. Conclusion: It was concluded that the luminol solution is effective in detecting blood tissue in endodontic files as well as in validating the cleaning/sterilization process.

Introdução: Sangue é um material biológico com alto potencial de transmissão de infecção em ambientes odontológicos, incluindo herpes simples, hepatites e AIDS. Objetivo: Investigar a eficácia do luminol em detector sangue em limas endodônticas antes e após o processo de esterilização. Material e método: Luminol foi utilizado para investigar a presença ou ausência de vestígios tecido sanguíneo em 50 limas endodônticas, visíveis ou não à olho nu, após a realização do tratamento endodôntico e após o processo de limpeza/esterilização. Os resultados obtidos foram tabulados e analisados estatisticamente utilizando o teste de Friedman com nível de significância de 5% (p<0,05). Resultado: A olho nú, foi observado que 31/50 limas não apresentaram vestígios de sangue, 8/50 apresentaram uma leve presença de sangue e 11/50 apresentaram uma presença considerável de sangue após o tratamento endodôntico. Após a utilização do luminol, entretanto, 16/50 limas endodônticas não apresentaram vestígios de sangue, 19/50 apresentaram uma leve presença de sangue e 15/50 apresentaram uma presença considerável de sangue. Após o processo de limpeza e esterilização não foi detectado sangue nas limas endodônticas. Conclusão: A solução de luminol é efetiva na detecção de tecido sanguíneo em limas endodônticas, validando o processo de limpeza/esterilização.

Comparación en los niveles de ansiedad en pacientes previo a la realización de terapia endodóntica y periodontal / Comparison of anxiety levels in patients prior to performing endodontic and periodontal treatment

La ansiedad que generan los tratamientos odontológicos generalmente perturba el comportamiento de los pacientes constituyéndose en una problemática que dificulta, retarda y muchas veces impide la realización de los procedimientos dentales. Este estudio tiene por objetivo comparar los niveles de ansiedad rasgo (estado emocional de base) y de ansiedad estado (situación emocional transitoria) a 80 pacientes (40 hombres y 40 mujeres) que asistieron a las clínicas de pregrado de la Universidad Mayor. Antes de realizar el tratamiento propiamente dicho de patologías endodónticas y periodontales asintomáticas se aplicó la encuesta inventario STAI a toda la muestra, que fue dividida en 2 grupos. Grupo A: 40 pacientes (20 hombres y 20 mujeres) que iban a ser sometidos a terapias endodónticas. Grupo B: 40 pacientes (20 hombres y 20 mujeres) que iban a ser sometidos a terapias periodontales. Resultados Los pacientes manifestaron diferencias significativas en la ansiedad rasgo (p < 0,2473) y ansiedad estado (p < 0,0329) cuando enfrentaron tratamientos periodontales versus endodónticos. Al comparar en hombres y mujeres la ansiedad rasgo/estado, se encontraron diferencias significativas (p < 0,05). Conclusiones Los pacientes manifiestan mayor ansiedad cuando tienen que enfrentar tratamientos periodontales. Las mujeres enfrentan ambos tratamientos dentales con mayor ansiedad que los hombres.

Anxiety generated by dental treatment usually affects the behaviour of patients, and this is a problem that can impede patients from seeking treatment, or complicate or delay dental procedures. The objective of this study is to compare the state anxiety (normal state of anxiety on the day to day basis) and trait anxiety (arousal of anxiety due to a particular situation) levels in 80 patients (40 women and 40 men) who sought treatment at the undergraduate clinic at the Universidad Mayor. Before being treated for asymptomatic endodontic and periodontal diseases the State-Trait Anxiety Inventory questionnaire was completed in group A: 40 endodontic patients, and group B: 40 periodontal patients (men and women were evenly distributed between groups). Results Patients showed significant differences in trait anxiety (P = .2473) and state anxiety (P = .0329) before periodontal treatments versus endodontic treatments. Significant differences were found in the Trait/State Anxiety significant differences (P = .05) when comparing men and women. Conclusions (i) Patients feel more anxiety when faced with periodontal treatments than when faced with endodontic treatments, and (ii) women feel more anxiety than men when faced with either dental treatment.

Photonic real-time monitoring of bacterial reduction in root canals by genetically engineered bacteria after chemomechanical endodontic therapy

Microbial infection plays an important role in the development of pulp necrosis and formation of periapical lesions. In vitro and in vivo research in this field, traditionally microbiological culture methods using paper point sampling and quantitative culture, faces difficulties in completely removing bacteria from the root canal system and analyzing sequential procedures. This study employed genetically engineered bioluminescent bacteria and a light-sensitive imaging system to allow real-time visualization of the infection. Ten extracted teeth incubated with P. aeruginosa were treated by mechanical instrumentation with K-files (#30 K-file, #35 K-file and #40 K-file) and chemical irrigation with sodium hypochlorite and hydrogen peroxide. Irrigation alone reduced the contamination in 18 percent; the first chemomechanical sequence (instrumentation with a #30 K-file + irrigation) provided 41 percent of reduction; the second sequence (#35 K-file + irrigation) achieved 62 percent; and the complete therapy (#30 K-file + #35 K-file + #40 K-file + irrigation) achieved 93 percent of bacterial reduction. These results suggest that the endodontic treatment is dependent on the association of a chemical and mechanical approaches and that root canal enlargement improves bacterial reduction probably because the irrigation has more access to the apical third.

Infecções microbianas são um dos fatores principais no desenvolvimento de necrose pulpar e lesões periapicais. Tradicionalmente, estudos in vivo e in vitro utilizam cultura microbiológica com coletas com cones de papel e quantificação de unidades formadoras de colônia. A maior desvantagem deste método é a dificuldade de se remover as bactérias dos canais radiculares e a impossibilidade de promover a análise seqüencial deste procedimento. Este estudo empregou bactérias geneticamente modificadas para apresentarem bioluminescência e um sistema sensível a baixa luminosidade, permitindo a visualização em tempo-real da área infectada. Dez dentes extraídos foram incubados com P. aeruginosa e tratados endodonticamente com instrumentação mecânica com limas K (#30, #35 e #40) e irrigação com hipoclorito de sódio e peróxido de hidrogênio. A irrigação sozinha reduziu a contaminação inicial em 18 por cento; a primeira seqüência de lima e irrigação (lima #30) obteve 41 por cento de redução; a segunda seqüência (lima #35 e irrigação) obteve 62 por cento; e o tratamento completo (lima #30, lima #35, lima #40 e irrigação) reduziu a contaminação bacteriana inicial em 93 por cento. Os resultados sugerem que o tratamento endodôntico é dependente da associação dos procedimentos químico-mecânicos que promovem o alargamento do canal radicular, otimizando a redução microbiana, possivelmente devido ao maior acesso das substâncias químicas à porção apical do canal radicular.