Eficácia das manobras de desbridamento no preparo químico-mecânico quanto à desinfecção no terço apical em molares humanos / Efficacy of chemo-mechanical preparation debridement procedures in disinfection of the apical third of human molar root canals

Objetivo: Avaliar a eficácia das manobras de desbridamento no preparo químico-mecânico (PQM) quanto a limpeza e desinfecção no terço apical em molares humanos. Material e método: Cinquenta raízes mesiais de molares inferiores humanos com dois canais radiculares foram inoculadas com E. faecalis e distribuídas aleatoriamente em cinco grupos (n=10). O PQM foi realizado com o sistema Protaper associado ao desbridamento com as limas Kerr #10 (G1 e G3) e as limas Kerr #15 (G2 e G4). O G5 representou o controle positivo, o qual foi submetido apenas ao PQM, sem receber o desbridamento. Outra variável foi o uso da medicação intracanal (MIC) à base de hidróxido de cálcio (Calen), que foi aplicada aos grupos G3 e G4. A irrigação foi feita com hipoclorito de sódio 2,5% e EDTA 17%. A análise da ação antimicrobiana se deu através da contagem das unidades formadoras de colônias (UFC). Resultado: Foram aplicados o Teste Kruskal-Wallis (nas análises imediatas) e o Teste Mann-Whitney (nas análises mediatas), ambos com p=0,01. A análise imediata ao PQM apresentou-se sem diferença estatística entre os grupos (p=0,11). No G4 (#15 + MIC), os resultados das coletas mediatas foram estatisticamente significantes (p=0,01). Conclusão: O desbridamento com as limas Kerr #10 e #15 não apresentou diferença significativa quanto à redução das colônias de E. faecalis quando comparado ao grupo em que não se realizou o desbridamento. Nos espécimes em que se aplicou a MIC, o desbridamento com a lima Kerr #15 (G4) foi mais eficiente do que a lima Kerr #10 (G3) em reduzir as UFC.

Aim: The aim of this in vitro study was to evaluate the efficacy of chemo-mechanical preparation (CMP) debridement procedures in regard to cleansing and disinfection of the apical third of human molar canals using different protocols. Material and method: Fifty mesial roots of human mandibular molars containing two canals were inoculated with E. faecalis strains and randomly allocated to five groups (n=10). CMP was carried out with the rotatory Protaper system associated with Kerr files #10 (G1 and G3) and #15 (G2 and G4). G5, the positive control, was subjected to CMP without debridement. Another variable studied was the use of calcium hydroxide-based temporary intracanal medication (Calen) prior to the chemo-mechanical performed in the G3 and G4 groups. Irrigation was performed with 2.5% sodium hypoclorite and 17% EDTA. Antimicrobial activity was quantified by counting the number of colony-forming units (CFU). Result: Kruskal-Wallis was used for immediate analyses and Mann-Whitney for mediate analyses both with a stipulated value of significance of p=0.01. In the imediate analyses following CMP there were no significant differences among the groups (p=0.11). In the G4 (#15 + MIC) the results of the mediate collections were statistically significant (p=0.01). Conclusion: Debridement with #10 and #15 Kerr files did not produce significant differences in regard to reduction of E. faecalis when compared to the positive control. In samples where Calen intracanal medication was used debridement with #15 Kerr files was more efficient in reducing the number of CFUs than #10 Kerr files.

Shear Bond Strength and Adhesive Remnant of Three Protocols used for Bonding Orthodontic Brackets

Objective: To test the shear bond strength and the amount of adhesive remnant on the enamel after debonding of a conventional orthodontic composite system, a flowable composite resin, and a self-adhesive resin cement. Material and Methods: Thirty extracted bovine incisors were allocated in three groups, according to the type of adhesive: Group XT (Transbond XT), Group FL (Flow Z350), and Group RX (RelyX U100). All groups had etching with phosphoric acid. Groups XT and FL received primer before adhesive. Stainless steel metal brackets were bonded using the respective adhesive. Teeth were submitted to shear bond strength (SBS) test, followed by measurement of adhesive remnant. Intergroup comparison of SBS values were performed by one-way Anova and Tukey post-hoc test. Kruskal-Wallis test and the Mann-Whitney U-test were used to compare adhesive remnant. Results: Transbond XT presented higher bond strength than RelyX U100 and Flow Z350; all adhesives exhibited bond failure within the adhesive. All groups showed bond failure occurring within the adhesive. Transbond XT and RelyX U100 left significantly more adhesive remnant on the tooth surface than Flow Z350. Conclusion: All three adhesive systems had bond strength above the minimum for clinical routine use. As regards to bond strength, Transbond XT performed better than the resin cement and the flowable resin. Bond failure occurred within the adhesive in all groups.

Incorporation of disinfectants for obtaining dental stone: microbiological and dimensional evaluation / Incorporação de desinfetantes para obtenção de modelos de gesso: avaliação microbiológica e dimensional

Aim: To assess dimensional change and antimicrobial activity of disinfectants substances incorporated during the dental stone manipulation. Material and Method: In vivo - microorganisms were collected in alginate molds of 30 volunteers inoculated on BHI agar and incubated at 37 °C for 24 hours. The molds were cast with type IV gypsum, manipulated with saline (G1), 1% sodium hypochlorite (G2) and 4% chlorhexidine (G3), replacing the water. After setting of plaster with 1 hour two collections on models were made. After 24 hours, the readings were performed. The Kruskal-Wallis and Wilcoxon tests with confidence interval of 99% and 95% respectively were used. In vitro - Müeller Hinton agar petri dishes were inoculated with S. mutans (ATCC25175), S. sanguis (ATCC10556) and E. faecalis (ATCC29212), over which were placed steel rings filled with the same substances of the in vivo study. After deposition of gypsum and incubation, halos were measured with a digital caliper and data were submitted to ANOVA and Tukey's test with confidence interval of 95%. Dimensional Change - With a metallic matrix and a perfectly adapted tray, the insertion axis and force used for moulding and obtain 30 specimens in type IV gypsum were standardized, following the same distribution of the study groups in vivo. The specimens were measured by Image Pro Plus software and data were submitted to ANOVA and Tukey's test with confidence interval of 95%. Result: Data from the in vivo study demonstrated a significant difference between the mold and each model (p<0.001). In the Wilcoxon test there was no significant difference between groups of models. At the in vitro test, G2 showed greater inhibition zones in all micro-organisms tested compared to G3, but with respect to dimensional changes, there was a significant difference between solutions and metallic standard, where G3 caused less change than G2. Conclusion: Chlorhexidine 4% showed to be the most suitable disinfectant. .

Objetivo: Avaliar alteração dimensional e ação antimicrobiana de substâncias desinfetantes incorporadas durante manipulação do gesso. Material e Método: In vivo - Micro-organismos foram coletados com swabs dos moldes de 30 voluntários, inoculados em Ágar BHI e incubados a 37 °C por 24 horas. Os moldes foram vazados com gesso tipo IV, manipulados com soro fisiológico (G1), hipoclorito de sódio 1% (G2) e clorexidina 4% (G3) substituindo a água. Decorrida 1 hora de presa fez-se duas coletas com swabs nos modelos, incubação e leituras das placas após 24 horas. Empregaram-se os testes Kruskal-Wallis e Wilcoxon com níveis de confiança de 99% e 95% respectivamente. In vitro - Inocularam-se S. mutans (ATCC25175), S. sanguis (ATCC10556) e E. faecalis (ATCC29212) em Ágar Müeller Hinton, onde posicionaram-se anéis de aço preenchidos com as mesmas substâncias do estudo in vivo. Após deposição do gesso e incubação, os halos foram medidos com paquímetro digital e os dados submetidos à ANOVA e Tukey com nível de confiança de 95%. Alteração dimensional - Com matriz metálica e moldeira perfeitamente adaptada padronizou-se eixo de inserção e força empregada para moldagem e obtenção de 30 corpos de prova em gesso tipo IV, seguindo a mesma distribuição dos grupos do estudo in vivo. Os corpos de prova foram mensurados pelo software Image Pro Plus e os dados submetidos à ANOVA e Tukey com nível de confiança de 95%. Resultado: Os dados do estudo in vivo demonstraram diferença significativa entre molde e cada modelo (p<0,001). No teste Wilcoxon não houve diferença significante entre grupos de modelos. In vitro- G2 apresentou maiores halos de inibição em todos micro-organismos testados em relação ao G3, mas com relação à alteração dimensional, houve diferença significante entre soluções e padrão metálico, onde G3 provocou menor alteração do que G2. Conclusão: Clorexidina 4% apresentou-se como o desinfetante mais adequado. .

Influence of the rotary and/or oscillatory reciprocating systems in the morphological changes of narrow and curved molar root canals anatomy / Influência dos sistemas rotatórios e/ou oscilatórios recíprocos nas alterações morfológicas anatômicas de canais radiculares atresiados e curvos

Objetivo: Esse estudo avaliou quatro sistemas endodônticos mecanizados, ProTaper Universal, K3 Endo, Twisted file, (rotatórios) e Endo - Eze TiLOS(oscilatório) para verificar e medir as alterações na anatomia original do canal radicular e desvios nos terços cervical,médio e apical. Material e Método: Foram utilizadas 60 raízes mésio-vestibulares de molares inferiores extraídos de humanos para coleta de medições de ângulos e classificação de Schneider. Os espécimes foram incluídos em resina de Éster vinil e montadas em muflas de Teflon, seccionadas transversalmente nos terços cervical,médio e apical para posterior fotografia usando-se câmera digital Cyber Shot DSC-TX10,acoplada à um microscópio 3101XY DFVasconcelos com 40× de aumento para se mensurar a àrea da secção anatômica transversal do canal radicular utilizando o programa AutoCAD 2008, comparando as àreas pré e pós instrumentação. Todos os espécimes ajustados na mufla foram radiografados de maneira padronizada para permitir a avaliação do ângulo de Schneider pré e pós-instrumentação.Uma vez coletados os dados,os mesmos foram comparados estatisticamente usando-se o programa BioEstat 5.0. Resultado: A análise dos resultados mostrou que no terço cervical os sistemas rotatórios foram mais eficazes que o sistema oscilatório Endo-Eze TiLOS,com diferenças estatisticamente significantes (p ≤ 0,05). As alterações anatômicas relativas ao desvio nos terços apical e médio foram similares, mas apicalmente o sistema ProTaper promoveu mais desvios quando se avaliou o ângulo de Schneider pré e pós instrumentação (p ≤ 0,05). Conclusão: Utilizando-se a alteração do ângulo de Schneider e a diferença entre área dentinária inicial (antes do preparo) e final (pós-preparo), concluiu-se que todos os sistemas causaram desvio na anatomia original do canal radicular.

Objective: This study evaluated four mechanized Endodontic systems, ProTaper Universal, K3 Endo, Twisted file (rotary) and the oscillatory reciprocating system Endo - Eze TiLOS, in order to verify and measure alterations in original anatomy with deviations at cervical, medium and apical root canal thirds. Material and Method: It was used MB root canals of 60 extract human lower molars, to produce a line of severe angles, according to the classification of Schneider. Samples were included in Ester vinyl resin, mounted in the Teflon Furnace, transversally sectioned at the cervical, middle and apical thirds, which were subsequently photographed using a digital camera Cyber Shot DSC-TX10,attached to an operating microscope 3101XY DFVasconcelos with 40× magnification in order to measure the anatomical transversal area of the root canal, using the software AutoCAD 2008, comparing pre and post-instrumentation. All samples assembled in the Furnace also were submitted to x-ray in a standardized way to enable the comparison of the angle of Schneider pre-and post-instrumentation. Once collected the data, they were compared statistically using the program BioEstat 5.0. Result: The analysis of the results showed that in the cervical third, rotary systems were more effective than Endo-Eze TiLOS System with statistically significant differences (p ≤ 0,05). Apical and middle third changes in anatomy were similar, but apically, the ProTaper system caused more deviations when comparing the angle of Schneider,and areas before and after instrumentation(p ≤ 0,05). Conclusion: It was concluded that all the systems caused alteration in the original anatomy of the root canal when parameters as angle of Schneider and areas before and after preparation were used.

Ultrasonic irrigation in the removal of smear layer and Enterococcus faecalis from root canals

Aim: This study evaluated both smear layer removal and reduction of Enterococcus faecalis after instrumentation with ultrasonic irrigation. Methods: Root canals were experimentally inoculated with E. faecalis for 20 days and microbiological samples were collected before and after chemomechanical preparation by using sterilized absorbent paper points. The irrigation solutions used were NaOCl 2.5% and EDTA 17%. In Group 1 (G1), conventional irrigation was used, whereas in Group 2 (G2) ultrasonic irrigation was performed. In group 3 (control), root canals were irrigated with distilled water. The samples were inoculated in BHI broth and turbidity was observed after 48 h to evaluate the reduction in the number of bacteria. Residual smear layer was examined by scanning electron microscopy (SEM). Results: The results showed no significant differences between ultrasonic and conventional irrigation. Conclusions: It was concluded that the level of disinfection and cleanliness of root canals achieved with ultrasonic irrigation is comparable to that obtained by conventional methods.

Clinical assessment of masticatory efficiency in the rehabilitation of edentulous patients

Rehabilitation of edentulous patients has been a constant concern in dentistry. Several studies have reported a reduction in the masticatory function in these patients. Osseointegrated implants have been used in order to obtain better masticatory efficiency, but more studies are needed to confirm these results. Aim: To evaluate the masticatory function of patients with conventional dentures and implant-supported dentures. Methods: A double-blinded controlled clinical study was conducted. The sample was composed of 60 patients divided into three groups: G1 with 20 patients with conventional upper (maxillary) and lower (mandibular) complete dentures, G2 with 20 patients with mandibular overdentures and upper (maxillary) complete dentures, and G3 with 20 patients with lower fixed implant-supported complete dentures (protocol). Objective data were collected through the masticatory efficiency test performed by the colorimetric method with the beads, in which capsules of a synthetic material enclosing fuchsine-containing granules were used. Results: A statistically significant difference was found for masticatory efficiency between groups G1 and G2 (pd"0.05) and between G1 and G3 (pd"0.05), and there was no statistically significant difference between G2 and G3 (pe"0.05). Conclusions: The results suggest that placement of osseointegrated implants in complete denture wearers improves their masticatory efficiency.

Condutas cirúrgicas nas osteossínteses das fraturas faciais pediátricas / Surgical management in osteosytheses of facial fractures in children

As fraturas faciais em pacientes pediátricos constituem um capítulo à parte na Traumatologia Buco-Maxilo-Facial. Devido ao alto grau de cicatrização e neoformação óssea, elas necessitam de uma rápida intervenção pela possibilidade de desenvolvimento de deformidades ou disfunções. Outro ponto crítico é a indicação de materiais de osteossíntese que não venham a interferir no crescimento do esqueleto facial ou não necessitem de segundo tempo operatório para sua retirada. Este trabalho traz uma revisão da literatura, apresentando o protocolo operatório do sistema reabsorvível no tratamento das fraturas faciais pediátricas.

Root canal microbiota of dogs' teeth with periapical lesions induced by two different methods.

OBJECTIVE: The microbial composition was investigated in root canals of dogs' teeth with periapical lesions induced by 2 different methods: open versus sealed canals. STUDY DESIGN: Teeth from Group I (n = 16) were left open for a week, then sealed with composite resin for 120 days. The teeth from Group II (n = 16) were left open for the same period. Microbiological samples from the root canals were collected and processed by the anaerobic technique for identification and counting of microorganisms after establishment of periapical reactions. RESULTS: Seventy-four cultivable isolates were recovered in sealed canals (Group I). Strict anaerobes accounted for 64.9% of all species isolated, and gram-negative microorganisms accounted for 55.4%. Microbial genera most frequently isolated were Prevotella, Fusobacterium, Peptostreptococcus, Streptococcus, Enterococcus, Clostridium, and Porphyromonas. Statistical analysis by Pearson chi-square or Fisher's test revealed positive association between sealed teeth and strict anaerobes (P < .05). In open canals (Group II), from a total of 58 cultivable isolates, 19% were strict anaerobes and 81% facultative anaerobes, with predominance of gram-positive species (75.8%). Genera most frequently isolated were Streptococcus, Propionibacterium, Staphylococcus, Neisseria, and Prevotella. CONCLUSION: Strict anaerobes were most frequently found in sealed teeth rather than in the teeth with canals left exposed to the oral cavity for 4 months. Therefore, the method that induced periapical inflammatory lesions by intentional oral exposure, followed by tooth sealing, produced root canal microbiota similar to the same found in humans.