Cyclic Fatigue Resistance of Blue Heat-Treated Instruments at Different Temperatures.

The main aim is to evaluate the cyclic fatigue resistance of blue heat-treated instruments with different kinematics. Twenty-four endodontic instruments of the same brand were used for each of three experimental groups: VB (Vortex Blue 40/0.04), RB (RECIPROC Blue 40/0.06), and XB (X1 Blue 40/0.06). The instruments were randomly distributed and subjected to temperatures of 20°C and 37°C. The fatigue test was performed using a stainless steel device. Data were analysed using the Shapiro-Wilk test, Student's t-test, the F test, and Tukey's and Tamhane tests at significance level P=0.05. The instruments' cyclic fatigue resistance at both temperatures differed significantly for each instrument type (P < 0.001). The RB instruments displayed greater cyclic fatigue resistance at the tested temperatures compared with the VB and XB instruments (P < 0.001). Reciprocating kinematics positively influenced cyclic fatigue resistance. Blue heat-treated instruments showed decreased cyclic fatigue resistance as the temperature increased (P < 0.001).

Influence of Temperature on the Cyclic Fatigue of Nickel-Titanium Instruments with Different Heat Treatments on Severely Curved Canals.

AIM: This study aims to investigate the influence of temperatures of 20 °C and 37 °C on the resistance to cyclic fatigue of NiTi instruments with different heat treatments, as tested in severely curved simulated canals. MATERIALS AND METHODS: Seventy-two instruments were distributed according to the temperature used (20 °C and 37 °C): XP-endo Shaper (30/0.01), ProDesign Logic (30/0.05), and iRaCe (30/0.04). The instruments were rotated freely until the occurrence of fracture inside an artificial severely curved stainless steel canal, which had a 90° angle of curvature and a curvature radius of 5 mm. Kolmogorov-Smirnov, Wilcoxon, ANOVA, and Kruskal-Wallis tests were performed. A p value of <0.05 was considered statistically significant. RESULTS: XP-endo Shaper instruments presented higher NCF values and time to failure compared with ProDesign Logic and iRaCe instruments at 20 °C and 37 °C (p < 0.001). CONCLUSION: Within the limitations of this study, the results show that the body temperature (37 °C) significantly lowers the resistance to cyclic fatigue of all instruments compared with 20 °C. CLINICAL SIGNIFICANCE: Body temperature is an important factor in the results of cyclic fatigue tests.

Tratamento com MTA Repair HP de extensa perfuração radicular após iatrogenia: relato de caso / Treatment with MTA Repair HP of extensive root perforation after iatrogeny: case report

Objetivo: relatar um caso clínico de perfuração radicular causada por iatrogenia, em terço cervical e médio de um incisivo central superior, dente 21, com presença de lesão óssea periapical. Relato de caso: clinicamente, pôde-se constatar ausência de edema e fístula. Na avaliação da condição pulpar e dos tecidos perirradiculares, o dente apresentou dor na palpação, ausência de mobilidade e de dor em percussão vertical e horizontal. Após os exames de imagem obtidos por meio de tomografia computadorizada de feixe cônico (TCFC; Prexion 3D), constatou-se lesão perirradicular extensa, canal radicular obliterado e perfuração radicular em face vestibular após tentativa de acesso cirúrgico. Como escolha de tratamento, optou-se por recuperar o trajeto original do canal de maneira a obter acesso intracanal, realização do preparo químico-mecânico e obturação pela técnica do cone único, para posteriormente promover o selamento adequado da perfuração com MTA Repair HP (Angelus, Londrina, PR, Brasil). Após seis meses, o dente apresentava-se assintomático e, radiograficamente, observou-se o reparo da lesão periapical. Considerações finais: o correto planejamento, o conhecimento dos materiais utilizados e a abordagem terapêutica foram de suma importância para o manejo adequado do caso. (AU)

Objective: to report a clinical case of root perforation, caused by iatrogeny in the cervical and middle third of an upper central incisor, tooth 21, with presence of periapical bone lesion. Case report: clinically, there was no edema and fistula. Facing the evaluation of the pulp condition and the periradicular tissues, the tooth presented pain on palpation, absence of mobility and pain on vertical and horizontal percussion. After the imaging exams, obtained by cone-beam computed tomography (CBCT; Prexion 3D), extensive periradicular lesion, obliterated root canal and root perforation were observed in the buccal face after attempted surgical access. As a choice of treatment, we chose to recover the original path of the canal in order to obtain intracanal access, chemicomechanical preparation and obturation by the single-cone technique to later promote proper sealing of the perforation with MTA Repair HP (Angelus, Londrina, PR, Brazil). After six months, the tooth was asymptomatic and, radiographically, the repair of the periapical lesion was observed. Final considerations: the correct planning, knowledge of the materials used and therapeutic approach were of paramount importance for the proper management of the case. (AU)

Associação da terapia fotodinâmica no tratamento endodôntico de lesão perirradicular extensa em sessão única ­ relato de caso / Association of photodynamic therapy in endodontic extensive perirradicular injury treatment in a single session ­ case report

O tratamento endodôntico em sessão única tem sido alvo de inúmeras discussões entre a comunidade da Endodontia, isso pelo ponto de vista da eficiência do tratamento, biologia, conforto, dor e preferência do paciente. Este artigo tem como objetivo relatar um caso clínico de tratamento endodôntico não cirúrgico de lesão perirradicular extensa realizado em sessão única associado à terapia fotodinâmica em um incisivo lateral superior. Ao exame clínico, o teste de sensibilidade ao frio respondeu negativamente, enquanto o teste de percussão vertical respondeu positivamente. No exame radiográfico, foi observada restauração insatisfatória com sinais de infiltração e rarefação óssea periapical extensa envolvendo o ápice do dente 12. Procedeu-se ao tratamento endodôntico em sessão única com complementação de terapia fotodinâmica. O acesso ao canal radicular foi realizado com a broca esférica e refinamento. Realizou-se a instrumentação do canal fazendo uso de sistema convencional com limas tipo K-file, em técnica coroa-ápice. A cavidade recebeu o fotosensibilizador azul de metileno (0,01%) por 3 minutos, seguido por irradiação com laser de diodo (100 mW e 660 nm) por 3 minutos. Foi realizada proservação radiográfica por um período de 11 meses. Concluiu-se que o tratamento endodôntico não cirúrgico em sessão única, em dentes necrosados com lesão periapical extensa, em associação a PDT, foi satisfatório no caso relatado, tendo indícios satisfatórios de neoformação óssea, regressão da lesão e ausência de sintomatologia (AU).

Single session endodontic treatment has been subject of numerous discussions among the endodontic community, due to its efficiency, biology, comfort, pain, and patient preference. This paper aims to report a clinical case of non- surgical endodontic treatment of extensive periradicular lesion performed in a single session associated with photodynamic therapy in a upper lateral incisor. At clinical examination, cold sensitivity test responded negatively, while the vertical percussion test responded positively. At radiographic examination unsatisfactory restoration was observed with infiltration signs and extensive periapical bone rarefaction involving the apex tooth 12. Single session endodontic treatment was performed in addition to photodynamic therapy. Root canal access was performed with the spherical drill and refinement. The canal instrumentation was performed using a conventional K-file type system, with crown-apex technique. The cavity received methylene blue photosensitizer (0.01%) for 3 minutes, followed by diode laser irradiation (100 mW and 660 nm) for 3 minutes. Radiographic proservation was performed for a period of 11 months. It can be concluded that non-surgical endodontic treatment in a single session in necrotic teeth with extensive periapical lesion in association with PDT was satisfactory in the case reported, with satisfactory evidence of bone neoformation, lesion regression and absence of symptoms (AU).

O dilema do cirurgião-dentista na decisão da extração dos terceiros molares / The Dentist's Quandary in the decision of the Third Molar's extraction

O apinhamento é uma das oclusopatias mais frequentes, que compromete tanto a harmonia estética do sorriso quanto a harmonia oclusal. Caracteriza-se pela falta de espaço no arco para acomodar os elementos dentários de maneira harmônica. Por volta da adolescência e pós-adolescência, principalmente nos elementos anto-inferiores, a referida patologia tende a se manifestar/agravar, incomodando bastante os pacientes. Por ocorrer no período próximo da erupção dos terceiros molares, estes acabam sendo associados à manifestação do apinhamento. Diante do problema, o presente trabalho objetivou realizar uma revisão literária nos bancos de dados da MEDLINE e BBO, VG nos últimos 10 anos (1999 até 2009) sobre as principais correntes existentes a respeito da influência dos terceiros molares inferiores no apinhamento tardio e do dilema enfrentado pelo cirurgião-dentista na decisão de indicar a exodontia.

The crowding is one of the vulgarity diseases and in such a way compromises the aesthetic harmony of the smile and also the harmony of the occlusion. It is characterized by the lack of space in the arc to accommodate the dental elements of harmonic form. In the adolescence and after-adolescence, mainly in the previous and inferior elements, the crowding tends if to reveal/to aggravate sufficiently inconvenience the patients. For occurring in the period next to the eruption of the third molar, the third molar are associated with the manifestation it crowding. Ahead of the problem, the present work objectified to carry through a literary revision in the data bases of MEDLINE and BBO in last the 10 years (1999-2009) on main existing chains regarding the influence of the third molar lower in the crowding late and of the quandary faced for the dentist in the decision to indicate the extraction.