Effect of Root Canal Preparation on Propagation of Dentinal Microcracks.

Introduction: This study evaluated the propagation of dentinal microcracks and the root canal volume increase after being prepared with two endodontic instruments: ProTaper Next (PTN) and WaveOne Gold (WOG) by micro-computed tomography analysis. Methods and Materials: We selected 48 maxillary molars randomly distributed in two groups: PTN and WOG. The samples were scanned before and after instrumentation, and then the image analysis was performed to detect the propagation of pre-existing dentinal micro-cracks and calculate the pre- and post-instrumentation volume. The statistical analysis was performed using Student's t-test, Fisher's exact test, and ANCOVA (P<0.05). Results: Dentinal microcracks were observed in 95.8% of the samples, both PTN and WOG instruments propagated microcracks after instrumentation, but there was no significant difference between the instruments (P=0.538). In relation to the root canal volume there was no statistic difference between PTN and WOG systems for the mesiobuccal (P=0.426) and distobuccal root canals (P=0.523). Conclusion: We can conclude that both ProTaper Next and WOG systems propagate dentinal microcracks after root canal preparation in this in vitro study, without statistical significance. The root canal volume prepared also showed no statistically significant difference between the two groups. This in vitro study requires further studies for more concrete conclusions.

Descoloração da coroa após obturação endodôntica com diferentes cimentos: estudo clínico / Crown discoloration after endodontic obturation with different cements: a clinical study

Objetivo: O objetivo do presente estudo foi avaliar clinicamente a descoloração da coroa dentária após obturação do canal radicular com diferentes cimentos endodônticos. Métodos: Trinta e dois dentes foram tratados endodonticamente e obturados com AH Plus (AHP), Endofill (END), MTA Fillapex (MTA) ou Sealer 26 (SEA), divididos em oito pacientes por grupo. O registro das cores foi realizado com um espectrofotômetro antes da intervenção (T0 ), aos 30 (T1 ) e aos 90 dias após a intervenção (T2 ). As avaliações foram feitas no centro da coroa dentária e a variação de cor (ΔE) foi calculada por meio da Commission International de l'Eclai- rage (CIE) L*a*b. Um operador, especialista em Endodontia, realizou os procedimentos clínicos. Os dados foram submetidos a medidas repetidas ANOVA e teste de Tukey (Δ=5%). Resultados: Não houve diferença estatisticamente significativa na variação de cores entre os cimentos (AHP ΔE=4,11; END ΔE = 6,34; SEA ΔE = 8,77 e MTA ΔE = 12,15), p>0,05. Porém, houve diferença entre os períodos analisados (T1ΔE= 5,65; T2 ΔE = 10,02). Conclusões: Dentro das limitações deste estudo, todos os cimentos endodônticos causaram alterações cromáticas clinicamente perceptíveis na coroa dentária. No entanto, o AH Plus promoveu menos alterações cromáticas na coroa dentária (AU).

Introduction: The aim of this study was to evaluate the crown discoloration after root canal filling with different endodontic cements clinically. Methods: Thirty-two teeth were endodontically treated and filled with AH Plus (AHP), Endofill (END), MTA Fillapex (MTA), or Sealer 26 (SEA), divided into eight patients per group. Color recording was performed with a spectrophotometer before the intervention (T0 ) and at 30 (T1 ) and 90 days post-intervention (T2 ). The evaluations were done in the center of the dental crown and color variation (ΔE) was calculated by means of the Commission International de IEclairage (CIE) L*a*b. The data were subjected to repeated measures ANOVA and Tukeys test (alpha=5%). Results: There was no statistically significant difference in color variation between the cements (AHP ΔE=4.11; END ΔE=6.34; SEA ΔE=8.77, and MTA ΔE=12.15), p>0.05. However, there was a difference between the periods tested (T1 ΔE=5.65; T2 ΔE=10.02). Conclusions: All tested endodontic cements altered the color of dental crowns (AU).

Effects of 1-Ethyl-3-(3-Dimethylaminopropyl) Carbodiimide on Adhesion of Posts in Teeth Obturated With Different Sealers.

The aim of this study was to evaluate the effect of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) on bond strength of fiberglass posts in root canals obturated with different endodontic sealers. Seventy-eight mandibular premolars were obturated with three sealers (n=26): Endofill (END), AH Plus (AHP), and Endosequence BC Sealer (EBS). After preparation of the post space, two subgroups were formed according to the cementation of the posts (n=13): with EDC (EDC), and without EDC (control - CON). The specimens were submitted to a pull-out test, failure mode classification, and root canal surface evaluation by scanning electron microscopy after post displacement. Regarding the bond strength, a significant difference between the EDC and CON subgroups occurred only in the END (p=0.001). No difference was detected among the CON subgroups (p=0.339). However, among the EDC subgroups, AHP presented significantly higher values (END versus AHP: p=0.001; AHP versus EBS: p=0.016). Upon classification of failure modes, score 1 (≥ 50% of cement) was the most commonly observed, except for the END + EDC. Remains of endodontic sealers and resin cements were found in the cervical third, but without statistical difference (p=0.269), while in the middle third, difference occurred (p=0.004). In conclusion, EDC decreases bond strength when associated with END sealer, without changing the failure mode between the resin cement and fiberglass post. The best performance was observed when EDC was combined with AHP sealer.

Effects of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide on adhesion of posts in teeth obturated with different sealers

Abstract The aim of this study was to evaluate the effect of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) on bond strength of fiberglass posts in root canals obturated with different endodontic sealers. Seventy-eight mandibular premolars were obturated with three sealers (n=26): Endofill (END), AH Plus (AHP), and Endosequence BC Sealer (EBS). After preparation of the post space, two subgroups were formed according to the cementation of the posts (n=13): with EDC (EDC), and without EDC (control - CON). The specimens were submitted to a pull-out test, failure mode classification, and root canal surface evaluation by scanning electron microscopy after post displacement. Regarding the bond strength, a significant difference between the EDC and CON subgroups occurred only in the END (p=0.001). No difference was detected among the CON subgroups (p=0.339). However, among the EDC subgroups, AHP presented significantly higher values (END versus AHP: p=0.001; AHP versus EBS: p=0.016). Upon classification of failure modes, score 1 (≥ 50% of cement) was the most commonly observed, except for the END + EDC. Remains of endodontic sealers and resin cements were found in the cervical third, but without statistical difference (p=0.269), while in the middle third, difference occurred (p=0.004). In conclusion, EDC decreases bond strength when associated with END sealer, without changing the failure mode between the resin cement and fiberglass post. The best performance was observed when EDC was combined with AHP sealer.

Resumo O objetivo deste estudo foi avaliar o efeito da 1-etil-3- (3-dimetilaminopropil) carbodiimida (EDC) na resistência de união de pinos de fibra de vidro em canais radiculares obturados com diferentes cimentos endodônticos. Setenta e oito pré-molares inferiores foram obturados com três cimentos endodônticos (n=26): Endofill (END), AH Plus (AHP) e Endosequence BC Sealer (EBS). Após o preparo do espaço para pino, dois subgrupos formaram-se conforme a cimentação dos pinos (n=13): com EDC e sem EDC (controle - CON). Os espécimes foram submetidos ao teste pull-out, classificação do modo de falha e avaliação da superfície do canal radicular por microscopia eletrônica de varredura após o deslocamento. Quanto à força de resistência de união, uma diferença estatisticamente significativa ocorreu entre os subgrupos EDC e CON apenas no END (p=0,001). Não foi detectada diferença entre os subgrupos CON (p=0,339). Contudo, no subgrupo EDC, o AHP apresentou maiores valores (END versus AHP: p=0,001; AHP versus EBS: p=0,016). Acerca da classificação dos modos de falha, o escore 1 (≥50% de cimento) foi o mais comumente observado, exceto para END + EDC. Restos de cimentos endodônticos e cimentos resinosos foram encontrados no terço cervical, mas sem diferença estatística (p=0,269), enquanto no terço médio, houve diferença (p=0,004). Em conclusão, o EDC diminui a resistência de união quando associado ao cimento END, sem alterar o modo de falha entre o cimento resinoso e o pino de fibra de vidro. O melhor desempenho foi observado quanto o EDC foi usado com o cimento AHP.

Association between Pulp Stones and Kidney Stones: A Systematic Review and Meta-analysis.

INTRODUCTION: A systematic review and meta-analysis were performed to evaluate the association between pulp stones and kidney stones. METHODS: A search for observational studies was performed in PubMed, Scopus, Web of Science, Biblioteca Virtual em Saúde, and the gray literature. The Newcastle-Ottawa Scale for Risk of Bias criteria were used to evaluate the internal quality of the included studies. A fixed-effects meta-analysis was performed to evaluate the association between the conditions. RESULTS: A total of 213 studies were identified after the removal of duplicates. Of these, 9 studies were selected after screening the titles and abstracts. Finally, after full-text reading for qualitative analysis, 7 studies were selected, and of these, 2 were used in the meta-analysis. A significant association was found between pulp stones and kidney stones (1.97 [95% confidence interval, 1.21-3.18]; P < .05). CONCLUSIONS: This study revealed an association between pulp stones and kidney stones. Further well-designed studies should be conducted in order to confirm whether pulp stones are predictive indicators of undiagnosed kidney stones.

Influence of activation mode and preheating on intracanal irrigant temperature.

This ex vivo study assessed the effectiveness of two activation modes to increase the intracanal temperature of 5.25% NaOCl solution and the time for a preheated-irrigant to return to its initial temperature. Ten single-rooted extracted human teeth were used. Thermocouples were adapted to the root surface and the temperature was registered following two activation modes: ultrasound (US) and thermal. Furthermore, a preheated-solution (45°C/60°C) was flushed into root canal to test the time needed to return to its initial temperature. Data were analysed using two-way ANOVA and Tukey's post-hoc tests (P = 0.05). Statistical analysis showed differences between the activation modes. US and thermal activation increased from 37 to 40.4°C and to 62.8°C respectively in 60 s. Time for preheated-irrigant to return to its initial temperature was longer for 60°C. Preheating irrigant at 60°C and using thermal activation to keep it warm may represent a further step of the irrigation protocol.

Bond strength at the cement/dentin interface according to protocols for final irrigation of post space

Aim: The aim was to evaluate the bond strength at the cement/dentin interface in the post space, after specimens were treated with different final irrigation protocols, followed by cementation with a dual resin cement. Methods: Forty-eight extracted uniradicular human premolars were divided into four groups according to the irrigation (n = 12): control with distilled water; 2.5% sodium hypochlorite (NaOCl) + ethylenediaminetetraacetic acid (EDTA); 2.5% NaOCl + passive ultrasonic irrigation (PUI); and 2% chlorhexidine (CHX). The pull-out test was performed. The results were evaluated using ANOVA with Tukey's paired comparisons, with a significance of 5%. Results: When all groups were compared, significant difference occurred (p = 0.006), and in the paired comparison, NaOCl + PUI and CHX differed (p = 0.005). The CHX showed significantly higher adhesive defects between cement and dentin than other groups. Conclusions: The final irrigation protocol for cleaning after preparation for post space directly influences the bond strength at the cement/dentin interface

Percepção do estudante sobre a implantação do método OSCE no curso de Odontologia em uma universidade particular / Student's perception of the implementation of the OSCE method in the Dentistry course of a private university

O Objective Structured Clinical Examination (OSCE) é uma avaliação que observa e intervém nas inseguranças dos estudantes em uma condição clínica simulada. Essa forma de avaliar competências, habilidades clínicas, conhecimento, atitudes, comunicação e profissionalismo é considerada uma ferramenta importante no processo de ensino-aprendizagem. Nesse contexto, surgiu a necessidade em implementar, no curso de Odontologia, a avaliação de competência clínica OSCE. O objetivo do estudo foi avaliar a percepção do estudante de Odontologia sobre o método OSCE e seu impacto na formação acadêmica deles. Participaram 34 estudantes do último ano do curso. O instrumento de coleta de dados foi um questionário com opções de respostas ("discordo", "concordo", "concordo parcialmente", "indiferente") que foi respondido voluntariamente. Os dados foram submetidos ao teste Qui-quadrado que comparou as respostas das quatro aplicações da metodologia OSCE durante o ano, com nível de significância de 95% (p<0,05). Em relação à mesma pergunta, a diferença também foi significativa na última avaliação (93,1%; p=0,017). Quanto ao método ter contribuído para o futuro na prática profissional, 93,1% (p=0,042) dos estudantes concordaram, na última avaliação do ano. Pode-se concluir, com base na análise de resposta dos questionários nos quatro bimestres, que a percepção dos estudantes de Odontologia do 5á´¼ ano noturno da Universidade Positivo frente à introdução do método OSCE foi bem aceita e positiva, uma vez que a maioria das respostas indicaram que o método contribuiu significativamente para a formação e ofereceu oportunidade de aprendizagem (AU).

The Objective Structured Clinical Examination (OSCE) is used to detect and intervene in the students' lack of confidence in a simulated clinical condition. The OSCE assesses competences, clinical skills, knowledge, attitude, communication, and professionalism, being considered an important tool in the teachinglearning process. This context raised the need to implement the OSCE clinical competence assessment. The objective of the study was to assess the dentistry student's perception of the OSCE method and its impact on their academic training. This study included thirty-four sênior students. The data were collected using a multiple-choice questionnaire ("disagree", "agree", "partially agree", "indifferent") voluntarily answered. The chi-square test was used to analyze the data by comparing the answers of four OSCE methodology applications during the year, with a 95% (p <0.05) significance level. The difference was also significant regarding the same question in the last assessment (93.1%, p = 0.017). As for the method having contributed to their future professional practice, 93.1% (p = 0.042) of the students agreed in the last assessment of the year. Based on the analysis of questionnaire answers in the four bimesters, we concluded that the perception of the students attending the 5th year of dentistry at Positivo University is that the implementation of the OSCE method was well accepted and positive, since most of the answers indicated that the method significantly contributed to their training and provided learning opportunities (AU).

Implantação de um software para controle da central de esterilização do curso de Odontologia da Universidade Positivo / Implantation of software to control the sterilization department of the Dental School of Positivo University

O objetivo deste trabalho foi descrever um método de controle de esterilização dos materiais utilizados pelos acadêmicos de Odontologia, bem como comparar a sua eficiência frente ao antigo método de controle. Um software foi criado pela Gestão de Tecnologia da Informação da Universidade Positivo, a partir de uma demanda interna do curso, a fim de aprimorar o controle da central de esterilização. O novo método permite que etiquetas com código de barras sejam colocadas externamente em todas as caixas dos alunos, controlando todo o fluxo de entrada e saída de materiais, gerando maior segurança e agilidade do processo de esterilização. Além disso, o sistema permite que o professor tenha acesso à lista de todo o material esterilizado pelo aluno, bem como a data, horário e número da autoclave na qual o material foi esterilizado. Para avaliar a satisfação com o método foram entregues questionários para os estudantes do último ano do curso de Odontologia, contendo perguntas subjetivas sobre o novo e sobre o antigo método de controle. De acordo com o questionário aplicado, demonstrou-se que novo método utilizado diminui os atrasos para atendimento e o número de materiais danificados e perdidos, aumenta a segurança e acelera o tempo para a colocação e retirada dos materiais (p0,05). Na avalição geral, o método também se mostrou melhor quando comparado ao antigo (p0,001). Assim, conclui-se que o método implantado para o controle da esterilização proporcionou maior satisfação e segurança para os alunos (AU).

This study aims to describe a method for controlling the sterilization of materials used by dentistry students and to compare its efficiency against the former control method. A software was developed by the Information Technology Management Department at the Positivo University, motivated by an internal demand to improve the sterilizing department control. The new method allows the placement of labels with bar codes on the external surface of the students' boxes, controls the entire entrance-and-exit flow of materials and provides greater safety and agility for the sterilization process. Furthermore, the system allows professors to access the list of materials sterilized by students, and the date, time, and number of the autoclave in which the material was sterilized. Questionnaires including subjective questions about the new and former method of control were administered to final-year dentistry students to evaluate their satisfaction toward the methods. The new method decreases delays in patient care and the number of damaged and lost materials, increases safety, and reduces the time spent in material drop-off and withdrawal (p  better when compared to the former one (p  t the method implemented to control sterilization resulted in greater student satisfaction and provided greater safety (AU).

Immediate Implant Placement and Provisionalization Using the Patient's Extracted Crown: 12-Month Follow-Up.

STATEMENT OF PROBLEM: Immediate placement and provisionalization of implants in fresh sockets has been previously demonstrated to be a predictable treatment in the restoration of non-recoverable teeth in the anterior regions of the maxilla. PURPOSE: This article reports a clinical case in which an immediate implant placement protocol was used in combination with two distinct and sequential grafts (bovine bone and connective tissue, respectively) followed by immediate implant provisionalization using the patient's crown of an extracted tooth. CLINICAL REPORT: Physical, clinical, and image examinations of the patient (female, 23 years old) revealed a maxillary central incisor (tooth No. 8) with slight mobility due the presence of extensive cervical resorption. The treatment proposed was the atraumatic extraction of the tooth followed by immediate implant placement and provisionalization. Two grafts (bovine bone and connective tissue) were used due to the presence of a very thin maxillary bone plate associated with a thin gingival biotype. RESULTS: The use of the extracted crown as a temporary crown after immediate implant placement resulted in immediate attainment of an esthetically pleasing outcome and long-term favorable results. CONCLUSION: The treatment protocol proposed can be efficiently used to immediately restore the patient's esthetics and function while maintaining the health, volume, and contours of gingival tissues over a 12-month follow-up period. CLINICAL IMPLICATIONS: Anterior teeth extractions typically require the execution of single-unit prostheses using dental materials of synthetic origin (such as polymers), which often are incapable of achieving the esthetic and physiological results patients expect. The use of the patient's own crown was demonstrated, which allowed good clinical results to be achieved and the natural shape and function of tissues to be maintained.

Long-term evaluation of crown and root discoloration induced by different endodontic sealers

Aim: To evaluate crown and root discoloration promoted by different endodontic sealers after root canal filling. Methods: Eighty bovine incisors were prepared and filled with: Endofill, Sealer 26, AH Plus, and MTA Fillapex. Color was recorded using a spectrophotometer before endodontic treatment (T0) and at 24 hours (T1), seven days (T2), 30 days (T3), and 90 days (T4) after treatment. Analyses were performed on the middle and cervical regions of the crown, and on the cervical third of the root, immediately below the cementoenamel junction. The color alterations (ΔE) were calculated using Commission International de I'Eclairage (CIE) L*a*b parameters, and data were analyzed by analysis of variance (ANOVA) and Tukey's test (p<0.05). Results: All sealers induced color alterations. Sealer 26 resulted in the smallest changes in color (E = 5.32). The other materials did not present statistical differences (AH Plus E = 6.98; MTA Fillapex E = 6.88; Endofill E = 6.41). Of the three regions analyzed, the largest discoloration was observed at the cervical third of the root (E=10.67). In terms of time, the largest ΔE values (E=7.72) were observed at T4. Color changes at T1 (E=5.88), T2 (E=6.10), and T3 (E=5.89) were statistically similar. Conclusions: All endodontic sealers promoted discoloration on the tooth crown and root

Effectiveness of different final irrigation techniques and placement of endodontic sealer into dentinal tubules.

The aim of this study was to compare two irrigation techniques and four devices for endodontic sealer placement into the dentinal tubules. Ninety-nine single-rooted human teeth were instrumented and allocated to either the control (CO) (n=11) or experimental groups according to the irrigation method: syringe and NaveTip needle (NT) (n=44), and EndoActivator (EA) (n=44). These groups were subdivided according to sealer placement into K-File (KF), lentulo spiral (LS), Easy Clean (EC), and EndoActivator (EA) subgroups. Moreover, the distances of 5 mm and 2 mm from the apex were analyzed. The teeth were obturated with AH Plus and GuttaCore X3. Analyses were performed by scanning electron microscopy associated to cathodoluminescence. The percentage and maximum depth of sealer penetration were measured. Data were evaluated by three-way analysis of variance (ANOVA) and Games-Howell test (p<0.05). EA was superior to NT in percentage of sealer penetration. EC was significantly superior to EA (subgroup) for sealer penetration, and both improved the percentage of sealer penetration when compared to LS. Better sealer penetration was observed at the distance of 5 mm from the apex. Sealer penetration into the dentinal tubules was significantly improved by sonic irrigant activation.

Effectiveness of Persea major Kopp (Lauraceae) extract against Enterococcus faecalis: a preliminary in vitro study.

BACKGROUND: Persea major Kopp (Lauraceae) is a plant with wound healing, antibacterial, and analgesic properties. The aim of this study was to assess the in vitro antibacterial activity of the concentrated crude extract (CCE) and ethyl acetate fraction (EAF) of this plant against Enterococcus faecalis and compare it with calcium hydroxide [Ca(OH)2] paste and 2% chlorhexidine digluconate (CHX). METHODS: The plant material was collected, and an extract was prepared according to the requirements of the study (CCE and EAF). The minimum inhibitory concentrations (MICs) of CCE, EAF, Ca(OH)2, Ca(OH)2 + CCE, and CHX against E. faecalis were determined using the broth microdilution method RESULTS: The EAF inhibited E. faecalis at concentrations of 166.50, 83.25, and 41.62 mg mL-1, and 1.00, 0.50, and 0.25% of CHX solutions showed antimicrobial activity. The MICs of Ca(OH)2 paste were 166.50 and 83.25 mg mL-1, whereas Ca(OH)2 + CCE showed antimicrobial activity only at a concentration of 166.50 mg mL-1. CCE showed no inhibitory effect at any of the concentrations tested CONCLUSIONS: The CCE did not show any antimicrobial activity against E. faecalis; however, the EAF was the most effective among the three highest concentrations tested.

Effectiveness of different final irrigation techniques and placement of endodontic sealer into dentinal tubules

Abstract: The aim of this study was to compare two irrigation techniques and four devices for endodontic sealer placement into the dentinal tubules. Ninety-nine single-rooted human teeth were instrumented and allocated to either the control (CO) (n=11) or experimental groups according to the irrigation method: syringe and NaveTip needle (NT) (n=44), and EndoActivator (EA) (n=44). These groups were subdivided according to sealer placement into K-File (KF), lentulo spiral (LS), Easy Clean (EC), and EndoActivator (EA) subgroups. Moreover, the distances of 5 mm and 2 mm from the apex were analyzed. The teeth were obturated with AH Plus and GuttaCore X3. Analyses were performed by scanning electron microscopy associated to cathodoluminescence. The percentage and maximum depth of sealer penetration were measured. Data were evaluated by three-way analysis of variance (ANOVA) and Games-Howell test (p<0.05). EA was superior to NT in percentage of sealer penetration. EC was significantly superior to EA (subgroup) for sealer penetration, and both improved the percentage of sealer penetration when compared to LS. Better sealer penetration was observed at the distance of 5 mm from the apex. Sealer penetration into the dentinal tubules was significantly improved by sonic irrigant activation.

Bond Strength of Self-adhesive Resin Cement to Different Root Perforation Materials.

INTRODUCTION: Different materials have been used for intervening in root perforations. These materials are often in contact with resin cements used for cementation of intraradicular retainers. The aim of this study was to evaluate the bond strength of self-adhesive resin cement to different materials used to treat root perforations (mineral trioxide aggregate [MTA], Portland cement [PORT], and glass ionomer cement [GIC]). METHODS: Four discs (10 × 1 mm) of each material (the MTA, PORT, and GIC groups) were embedded into polyvinyl chloride tubes using acrylic resin, ground, and polished until a flat surface was exposed. Afterward, 4 silicone molds were used to prepare self-adhesive resin cement cylinders (0.7 × 1 mm) on each disc surface (N = 16). The specimens were stored in deionized water at 37°C for 24 hours and subjected to a microshear test. Then, the failure modes were examined. Data were submitted to statistical analysis (α = 0.05). RESULTS: The MTA and GIC groups showed significantly higher microshear bond strength values (3.36 ± 1.56 and 2.90 ± 1.49 MPa, respectively) than the PORT group (1.39 ± 0.77 MPa) (P < .05). Only adhesive failure modes were observed. CONCLUSIONS: When PORT was used as a root perforation material, GIC should be used as a base over it to improve shear bond strength with self-adhesive resin cement.

Resistance and Stress Finite Element Analysis of Different Types of Fixation for Mandibular Orthognathic Surgery

Abstract The aim of this study was to evaluate the stress and dislodgement resistance by finite element analysis of different types of fixation in mandibular orthognathic surgery. A 3D solid finite element model of a hemi-mandible was obtained. A bilateral sagittal split osteotomy was simulated and the distal segment was advanced 5 mm forward. After the adjustment and superimposing of segments, 9 different types of osteosynthesis with 2.0 miniplates and screws were simulated: A, one 4-hole conventional straight miniplate; B, one 4-hole locking straight miniplate; C, one 4-hole conventional miniplate and one bicortical screw; D, one 4-hole locking miniplate and 1 bicortical screws; E, one 6-hole conventional straight miniplate; F, one 6-hole locking miniplate; G, two 4-hole conventional straight miniplates; H, two 4-hole locking straight miniplates; and I, 3 bicortical screws in an inverted-L pattern. In each model, forces simulating the masticatory muscles were applied. The values of stress in the plates and screws were checked. The dislodgement resistance was checked at the proximal segment since the distal segment was stable because of the screen at the occlusal tooth. The regions with the lowest and highest displacement were measured. The offset between the osteotomized segments was verified by millimeter intervals. Inverted-L with bicortical screws was the model that had the lowest dislodgment and the model with the lowest tension was the one with two conventional plates. The results suggest that the tension was better distributed in the locking miniplates, but the locking screws presented higher concentration of tension.

Resumo O objetivo deste estudo foi verificar o estresse e a resistência ao deslocamento, pela análise de elementos finitos, de diferentes tipos de fixação em cirurgia ortognática mandibular. Um modelo 3D de elementos finitos sólidos de uma hemi-mandíbula foi obtido. Uma osteotomia sagital bilateral foi simulada e o segmento distal foi avançado 5 mm. Após o ajuste e sobreposição dos segmentos, foram simulados 9 diferentes tipos de osteossíntese com miniplacas e parafusos 2.0: A, uma miniplaca reta convencional de 4 furos; B, uma miniplaca reta lock de 4 furos; C, uma miniplaca convencional de 4 furos e um parafuso bicortical; D, uma placa lock de 4 furos e 1 parafuso bicortical; E, uma miniplaca reta convencional de 6 furos; F, uma miniplaca lock de 6 furos; G, duas miniplacas retas convencionais de 4 furos; H, duas miniplacas lock de 4 furos; e I, três parafusos bicorticais em um padrão L invertido. Em cada modelo foram aplicadas forças simulando os músculos mastigatórios. Foram verificados os valores da tensão nas placas e parafusos. A resistência ao deslocamento foi verificada no segmento proximal, uma vez que o segmento distal era estável. Foi medida a região com o maior deslocamento inferior e superior. O deslocamento entre os segmentos osteotomizados foi verificado por intervalos milimétricos. Parafusos bicorticais em L invertido foram o modelo que teve o menor descolamento inferior, e o modelo com a tensão mais baixa foi o de duas placas convencionais. Os resultados sugerem que a tensão foi melhor distribuída nas miniplacas do tipo lock, mas os parafusos de fixação apresentaram maior concentração de tensão.

Resistance and Stress Finite Element Analysis of Different Types of Fixation for Mandibular Orthognathic Surgery.

The aim of this study was to evaluate the stress and dislodgement resistance by finite element analysis of different types of fixation in mandibular orthognathic surgery. A 3D solid finite element model of a hemi-mandible was obtained. A bilateral sagittal split osteotomy was simulated and the distal segment was advanced 5 mm forward. After the adjustment and superimposing of segments, 9 different types of osteosynthesis with 2.0 miniplates and screws were simulated: A, one 4-hole conventional straight miniplate; B, one 4-hole locking straight miniplate; C, one 4-hole conventional miniplate and one bicortical screw; D, one 4-hole locking miniplate and 1 bicortical screws; E, one 6-hole conventional straight miniplate; F, one 6-hole locking miniplate; G, two 4-hole conventional straight miniplates; H, two 4-hole locking straight miniplates; and I, 3 bicortical screws in an inverted-L pattern. In each model, forces simulating the masticatory muscles were applied. The values of stress in the plates and screws were checked. The dislodgement resistance was checked at the proximal segment since the distal segment was stable because of the screen at the occlusal tooth. The regions with the lowest and highest displacement were measured. The offset between the osteotomized segments was verified by millimeter intervals. Inverted-L with bicortical screws was the model that had the lowest dislodgment and the model with the lowest tension was the one with two conventional plates. The results suggest that the tension was better distributed in the locking miniplates, but the locking screws presented higher concentration of tension.

Performance of Three Single Instrument Systems in the Preparation of Long Oval Canals.

This study aimed to evaluate the performance of the Wave One, Easy ProDesign Logic and One Shape systems in the preparation of long oval root canals. Forty-two mandibular incisors were randomized into three groups: Group I, Wave One Primary (WO) (#25.08); Group II, Easy ProDesign Logic (EPL) (#25.06) and Group III, One Shape (OS) (#25.06). Micro-computed tomography scans were obtained pre- and post-preparation of the samples. Instrument fractures or loss of working length did not occur in any of the groups. There was a statistically significant difference in total root canal volume between the WO and EPL (p<0.05) and OS systems (p<0.05) The mean percentages of instrumented canal area in the middle thirds were 76.9% in the WO, 62.3% in the EPL and 71.8% in the OS (p>0.05). The OS system had the strongest correlation between volume increase and instrumented area (R=0.63). The WO, EPL and OS systems presented mean preparation times of 2.13 min, 0.54 min, and 2.21 min (p<0.05), respectively. All three systems enabled the safe preparation of long oval root canals. The WO system most effectively increased root canal volume, but it did not affect the instrumented areas. The OS system had the strongest correlation between volume increase and instrumented area, while the EPL system was the fastest.

Performance of Three Single Instrument Systems in the Preparation of Long Oval Canals

Abstract This study aimed to evaluate the performance of the Wave One, Easy ProDesign Logic and One Shape systems in the preparation of long oval root canals. Forty-two mandibular incisors were randomized into three groups: Group I, Wave One Primary (WO) (#25.08); Group II, Easy ProDesign Logic (EPL) (#25.06) and Group III, One Shape (OS) (#25.06). Micro-computed tomography scans were obtained pre- and post-preparation of the samples. Instrument fractures or loss of working length did not occur in any of the groups. There was a statistically significant difference in total root canal volume between the WO and EPL (p<0.05) and OS systems (p<0.05) The mean percentages of instrumented canal area in the middle thirds were 76.9% in the WO, 62.3% in the EPL and 71.8% in the OS (p>0.05). The OS system had the strongest correlation between volume increase and instrumented area (R=0.63). The WO, EPL and OS systems presented mean preparation times of 2.13 min, 0.54 min, and 2.21 min (p<0.05), respectively. All three systems enabled the safe preparation of long oval root canals. The WO system most effectively increased root canal volume, but it did not affect the instrumented areas. The OS system had the strongest correlation between volume increase and instrumented area, while the EPL system was the fastest.

Resumo Este estudo teve como objetivo avaliar o desempenho dos sistemas Wave One, Easy ProDesign Logic e One Shape no preparo de canais radiculares ovais. Quarenta e dois incisivos inferiores foram randomizados em três grupos: Grupo I, Wave One primary (WO) (#25.08); Grupo II, Easy ProDesign Logic (EPL) (#25.06) e Grupo III, One Shape (OS) (#25.06). As amostras foram submetidas a microtomografia computadorizada antes e após o preparo. Não ocorreram fraturas de instrumento ou perda de comprimento de trabalho em qualquer dos três grupos. Houve diferença estatisticamente significante no volume total do canal radicular entre o WO e EPL. A média do percentual de área instrumentada do canal no terço médio foi 76,9% no grupo WO, 62,3% no grupo EPL e 71,8% no grupo OS (p>0,05). O sistema OS teve a correlação mais forte entre o aumento de volume e área instrumentada (R=0,63). Os sistemas WO, EPL e OS apresentaram tempos de preparo médios de 2,13 min, 0,54 min e 2,21 min (p<0,05). Todos os três sistemas foram seguros no preparo canais radiculares ovais. O sistema WO foi mais eficaz no aumento do volume de canal, entretanto, isso não afetou as áreas instrumentadas. O sistema OS teve a correlação mais forte entre o aumento de volume e área instrumentada, enquanto o sistema EPL foi o mais rápido.