Effect of the filling technique on the filling removal from oval-shaped canals.

OBJECTIVES: This ex vivo study aimed to evaluate the influence of different filling techniques on the filling removal from oval root canals filled with bioceramic sealer. METHODS: Thirty-six mandibular incisors with single oval canals were filled with bioceramic sealer following the techniques (n = 12): single-cone, modified McSpadden, or continuous wave of condensation, and scanned by micro-computed tomography (micro-CT). The filling was removed using the Clearsonic ultrasound tip and Reciproc system up to the R40 instrument, and the working time was recorded. The teeth were scanned again by micro-CT. Percentage of remnant volume (mm³) of the filling material, dentin thickness, and root canal transportation were measured. The data was analyzed using parametric and non-parametric tests with a significance level of 5%. RESULTS: It took more time to remove the filling material using the continuous wave of condensation technique (p < 0.05), followed by the modified McSpadden and single-cone techniques. There was no difference (p > 0.05) when comparing the percentage of remaining filling material among the three groups, nor did it among the segments of each tooth. There was also no difference in the analysis of dentin thickness and transportation when comparing the groups (p > 0.05). CONCLUSIONS: The filling technique did not influence the amount of remaining filling material, dentin thickness, and transportation. The working time was longer with thermoplastic filling techniques. CLINICAL RELEVANCE: Endodontic retreatment in teeth filled with bioceramic sealers increases with their use. Several techniques are used to fill the root canals, thus, it is important to know whether the filling technique influences the non-surgical endodontic retreatment.

Evaluation of Minimally Invasive Preparation of Curved Mesial Canals of Mandibular Molars - An In Vitro Study.

INTRODUCTION: Curved mesial roots can be challenging for different stages of endodontic treatment. Preparation aims to enlarge, clean, and shape the root canal system, and hundreds of systems are available to carry it out. Aiming to maintain pericervical dentin, minimally invasive preparation was proposed, and with it, instruments with lower tapers emerged. This study aimed to evaluate the increase in canal volume, the centering ability of the instruments, and root canal transportation of two different rotary systems with lower tapers. METHODS: Eighteen curved mesial roots of extracted mandibular molars were scanned by micro-CT at 3 moments: initial and after the 2 stages of endodontic preparation. The canals were prepared using TruNatomy (TN) and ProDesign Logic 2 (PDL2) instruments up to sizes 25.04 and 26.04, respectively, and after 36.03 and 35.05, respectively. The data were analyzed using parametric and nonparametric tests with a significance level of 5%. RESULTS: TN and PDL2 systems showed no difference regarding the increase in the volume of the canals with the first instruments, but after preparation with a diameter size of 35 or 36, there was a difference (P < .01) between the systems in the cervical and middle thirds. CONCLUSION: Both systems shaped the mesial canals of mandibular molars while keeping low transportation and good centering ability in enlargements up to diameter size 35 or 36 with tapers of 3 or 5%.

Shaping ability of three heat-treated NiTi systems in Vertucci's type III root canals of mandibular incisors: An ex vivo study.

Introduction: The anatomical configuration classified as Vertucci's type III is described as the second most prevalent in mandibular incisors. Methods: Thirty-six Vertucci's type III mandibular incisors were evaluated by micro-computed tomography (micro-CT) and divided into 3 groups (n = 12) according to the root canal preparation protocol (HyFlex CM [HCM], HyFlex EDM [HEDM], and Sequence Rotary File [SRF]). The teeth were scanned before and after performing 0.25 mm and 0.40 mm apical diameter preparations. The canal volume, dentin thickness, percentage of accumulated debris and untouched canal areas, transportation, and centering ability were measured. The data were statistically analyzed by ANOVA, Tukey, Kruskal-Wallis, and Dunn tests (P < 0.05). Results: The volume increase was more evident in the apical third. After 0.40 mm preparation, the SRF system provided a higher reduction (P < 0.05) in dentin thickness on the buccal surface 1 mm from the apex. There was higher canal transportation in the bucco-lingual direction. The 0.40 mm apical preparation reduced the percentage of untouched canal areas. The apical third had the highest percentage of untouched canal areas. The cervical third had the lowest volume of accumulated debris. Conclusions: Increasing the apical preparation to a diameter of 0.40 mm with the HCM, HEDM, and SRF systems in Vertucci's type III root canals of mandibular incisors proved to be safe and effective, reducing untouched canal areas. Clinical relevance: Root flattening can be intense to the point of generating a root canal bifurcation. Despite the decrease in the root canal diameter, a greater enlargement of the apical region is necessary and safe.

Biological response to lyophilized demineralized dentin matrix implanted in the subcutaneous tissues of rats.

AIM: Lyophilized demineralized dentin matrix (LDDM) consists of a type 1 collagen complex matrix containing growth factors and no mineral crystals. Although the efficacy of LDDM for bone grafting is well known, there is limited evidence on the biological response to human lyophilized DDM. Therefore, the aim of this study was to evaluate the biological response of subcutaneous tissues in rats to powdered LDDM, mineral trioxide aggregate (MTA), and Biodentine implanted using polyethylene tubes. METHODS: Forty Wistar rats were divided into four groups (n = 10 each) depending on the experimental time intervals and were placed in polyethylene tubes containing LDDM, MTA, biodentine, and one empty control. After 3, 7, 15, and 30 observation days, the animals were sacrificed and quantitative and qualitative analysis of the subcutaneous tissue samples was carried out. The intensity of the inflammatory response was scored from 0 (no response) to 3 (severe response), and the data were statistically analyzed using ANOVA and Bonferroni tests (p < 0.05). RESULTS: All groups exhibited moderate inflammation after 3 and 7 days of observation, with presence of inflammatory infiltrate predominantly consisting of macrophages and angioblastic proliferation being observed. After 15 observation days, the control group exhibited mild inflammation and a predominance of fibroblasts, and this differed significantly from the remaining cement groups that exhibited moderate inflammation. After 30 days of observation, all groups exhibited a mild inflammatory response, predominance of fibroblasts, and a greater amount of collagen fibers. CONCLUSION: Within the limitations of this study, it can be concluded that LDDM exhibited an acceptable biological response similar to MTA and Biodentine in the subcutaneous tissues of rats.

Pesquisa científica em Endodontia apresentada na Reunião Anual da Sociedade Brasileira de Pesquisa Odontológica: análise bibliométrica de 2010 a 2018 / Scientific production in Endodontics at the Meeting of the Brazilian Society for Dental Research: bibliometric analysis from 2010 to 2018

A Reunião anual da Sociedade Brasileira de Pesquisa Odontológica (SBPqO) é um importante evento da produção científica odontológica no país. A avaliação do perfil dos trabalhos apresentados pode identificar características e a evolução da pesquisa em Endodontia. Por meio desta análise bibliométrica retrospectiva buscou-se investigar a produção científica na área de Endodontia nos suplementos das reuniões da SBPqO, de 2010 a 2018. Os suplementos foram acessados on-line, no sítio web da instituição, e os resumos foram analisados de acordo com a região de origem: Norte, Nordeste, Centro-Oeste, Sul e Sudeste; e categorias temáticas: Terapêutica, Anatomia, Biossegurança, Microbiologia, Citologia/Genética, Diagnóstico, Epidemiologia, Materiais, Técnicas, Instrumentos, Traumatismo e Desfecho clínico. Dos 22.310 resumos publicados no período, foram selecionados 2516 da área de Endodontia. No ano de 2010 houve o maior número de resumos publicados (n=375). Prevaleceram as pesquisas voltadas à análise de materiais (27,1%) e de técnicas (20,6%). As regiões Sudeste e Sul apresentaram frequências de resumos com valores de 65,5% e 17,2%, respectivamente, enquanto a menor participação foi da região Norte (2,5%). A frequência de pesquisas de Endodontia publicadas nos resumos dos suplementos da SBPqO se manteve equilibrada ao longo do período analisado, com destaque para objetivos focados em materiais e técnicas e maior produtividade das regiões Sudeste e Sul (AU).

The annual meeting of the Brazilian Society of Dental Research (Sociedade Brasileira de Pesquisa Odontológica - SBPqO) is an important event of dental scientific production in the country. The evaluation of the profile of the presented research can identify characteristics and the evolution of Endodontics research. Through retrospective bibliometric analysis, meeting supplements from 2010 to 2018 were investigated to determine the scientific production in the area of Endodontics in SBPqO. The supplements were accessed online, via the institution's website, and the abstracts were analyzed according to region of origin: North, Northeast, Midwest, South and Southeast; and thematic categories: Therapeutics, Anatomy, Biosafety, Microbiology, Cytology/Genetics, Diagnosis, Epidemiology, Materials, Techniques, Instruments, Trauma and Clinical Outcome. Of the 22,310 abstracts published in the period, 2516 were selected from the Endodontics area. In 2010 there was the largest number of published abstracts (n = 375). Prevailed the research focused on the analysis of materials (27.1%) and techniques (20.6%). The Southeast and South regions presented summary frequencies with values of 65.5% and 17.2%, respectively, while the lowest participation was from the North region (2.5%). The frequency of Endodontic research published in SBPqO supplement remained balanced over the analyzed period, with emphasis on objectives focused on materials and techniques, and higher productivity in the Southeast and South (AU).