Comparative effects of final canal irrigation with chitosan and EDTA.

other: Chitosan is a natural, biocompatible chelating substance with potential for dental use. This study compared the effects of final canal irrigation with chitosan and EDTA on dentin microhardness, sealer dentin tubules penetration capacity, and push-out strength. METHODOLOGY: Fifty canine roots were distributed according to the final irrigation protocol (n=10): G1- 15% EDTA with conventional irrigation; G2- 15% EDTA with Endovac; G3- 0.2% chitosan with conventional irrigation; G4- 0.2% chitosan with Endovac; and G5- without irrigation. Specimens were obturated (AH Plus) and sectioned in 3 slices per root third. The first slice was used for microhardness and sealer penetration assessments under a laser confocal microscope. The second was utilized in a push-out strength test. The third slice was discarded. Data were analyzed using 2-way ANOVA and Tukey's post hoc test (α<0.05). Failure mode was determined at x40 magnification. RESULTS: Microhardness reduction was more significant in groups G2 and G4 (p<0.05). Sealer penetration through dentin was significantly greater in group G2 (p<0.05). There was no significant difference between groups G1, G3, and G4 (p>0.05). In general, all experimental groups presented similar bond resistance (p>0.05) that significantly differed from the control (p<0.001). Mixed type failures were predominant. CONCLUSIONS: In general, 0.2% chitosan and 15% EDTA solutions act in a similar manner with regard to the variables studied. The use of Endovac potentiates the effect of these solutions.

Smear layer removal and chelated calcium ion quantification of three irrigating solutions.

The purpose of this study was to evaluate, by scanning electron microscopy (SEM), smear layer removal and quantify, by atomic absorption spectrophotometry, the amount of calcium ion present in the chelating solutions after their use. Sixteen extracted canines were instrumented using the step-back technique and were assigned to 3 groups according to the irrigating solution used: G1: 1 mL 17% EDTAC between each file; G2: 1 mL 17% CDTA; G3: 1 mL 17% EGTA. The solutions were collected after use. The teeth were cleaved longitudinally, evaluated under SEM and assessed for smear layer by blinded examiners and scored from 1 to 4. In order to quantify calcium ion release, the collected solutions were examined by atomic absorption spectrophotometry. Freidman's test was used for statistical analysis of SEM values and showed that canals irrigated with 17% EDTAC and 17% CDTA had significantly less smear layer throughout the canals than 17% EGTA (p<0.01). For analysis of the collected solutions, Tukey's test was used and showed that EDTAC and CDTA had a greater amount of calcium ions (22.8+/-7.54 and 60.6+/-20.67 microg/mL, respectively) compared to EGTA (70.5+/-14.2 microg/mL) (p<0.01). The association both methodologies may contribute to the understanding of how these solutions act in the root canal.

Drying protocol influence on the bond strength and apical sealing of three different endodontic sealers.

The aim of this study was to evaluate the influence of drying protocols (DP) on the apical sealing (AS) and on the bond strength (BS) of teeth filled with different sealers. The root canals of one hundred and fifty-six roots of maxillary canines were prepared with Reciproc rotary files (R50). The teeth were randomly divided into four groups (n = 39), according to the DP: GI-paper points; GII-70% isopropyl alcohol + aspiration with NaviTip points; GIII-95% ethanol + paper points; GIV-EndoVac + paper points. Each group was divided into subgroups, according to the sealer used: AH Plus, Sealapex and MTA Fillapex, using a single-cone technique. Evaluation of AS and BS was performed with fluid filtration (FF) and push-out (PO) methods, respectively. The PO test consisted of sectioning the roots, and subjecting a single slice from each third to testing and analysis for failure type. The data was submitted to two-way and three-way variance analysis (ANOVA) and Tukey (α = 5%). The AS showed no drying protocol influence. The FF results revealed a statistically significant difference between MTA and Sealapex (p < 0.05) sealers. The BS test values showed that there was no statistical significant difference among the canal thirds (p > 0.05), but that there was such a difference among the sealers (p < 0.05), among the protocols (p < 0.05), and in the interaction between sealers and protocols (p < 0.05). AH Plus revealed the highest BS values among the sealers; the highest BS results for the sealers occurred with the specimens used with isopropyl alcohol, compared with ethanol and EndoVac.

Volume of sealer in the apical region of teeth filled by different techniques: a micro-CT analysis.

The volume of sealer in the apical 1 mm of teeth filled using different techniques was evaluated by micro-commuted tomography (micro-CT). Sixty-four maxillary central incisors were prepared using NiTi rotary instruments. Teeth were randomly distributed into four groups according to root canal sealers (AH Plus, Endofill, Sealapex, and Sealer 26) and subdivided into two subgroups according to the filling techniques (active and passive lateral condensation; n = 8 each). Subsequently, teeth were examined using the 1174 SkyScan micro-CT device. Images were reconstructed using the NRecon software, and the sealer volume (mm3) in the apical region was analyzed using the two-way ANOVA and post-hoc Student-Newman-Keuls test (α = 0.05). The lowest volume of sealer was observed in teeth filled with Sealapex (0.100 ± 0.009) and Endofill (0.103 ± 0.010). The highest volume was observed in teeth filled with AH Plus (0.112 ± 0.008) and Sealer 26 (0.109 ± 0.018) (p > 0.05). Regarding the filling technique, a lower sealer volume was observed using the active lateral condensation technique compared with that using the passive lateral condensation technique (0.100 ± 0.010 vs. 0.111 ± 0.012) (p < 0.05). Therefore, the lowest volume of sealer was observed in teeth filled with Sealapex and Endofill using the active lateral condensation technique.

Effect of different EGTA concentrations on dentin microhardness.

The effect of 1%, 3% and 5% EGTA (ethylene glycol-bis-(beta-amino-ethyl ether) N,N,N',N'-tetra-acetic acid) on the microhardness of root dentin of the cervical third of human teeth was studied. Five newly extracted maxillary incisors were sectioned transversely at the cementoenamel junction, and the crowns were discarded. The roots were embedded in blocks of high-speed polymerized acrylic resin and cut transversely into 1-mm sections. The second section of the cervical third of the root of each tooth was sectioned and divided into four parts. Each part was placed on an acrylic disc that was used as a base for microhardness measurement. Fifty microliters of 1% EGTA, 3% EGTA, or 5% EGTA were applied to the dentin surface. Deionized and distilled water was used as control. Dentin microhardness was then measured with a load of 50 g for 15 s. Statistical analysis showed that the three concentrations of the chelating solution EGTA significantly reduced dentin microhardness when compared with water (ANOVA, p < 0.01), and that there was a statistically significant difference among the three solutions (Tukey test, p < 0.05).

Drying protocol influence on the bond strength and apical sealing of three different endodontic sealers

Abstract The aim of this study was to evaluate the influence of drying protocols (DP) on the apical sealing (AS) and on the bond strength (BS) of teeth filled with different sealers. The root canals of one hundred and fifty-six roots of maxillary canines were prepared with Reciproc rotary files (R50). The teeth were randomly divided into four groups (n = 39), according to the DP: GI-paper points; GII-70% isopropyl alcohol + aspiration with NaviTip points; GIII-95% ethanol + paper points; GIV-EndoVac + paper points. Each group was divided into subgroups, according to the sealer used: AH Plus, Sealapex and MTA Fillapex, using a single-cone technique. Evaluation of AS and BS was performed with fluid filtration (FF) and push-out (PO) methods, respectively. The PO test consisted of sectioning the roots, and subjecting a single slice from each third to testing and analysis for failure type. The data was submitted to two-way and three-way variance analysis (ANOVA) and Tukey (α = 5%). The AS showed no drying protocol influence. The FF results revealed a statistically significant difference between MTA and Sealapex (p < 0.05) sealers. The BS test values showed that there was no statistical significant difference among the canal thirds (p > 0.05), but that there was such a difference among the sealers (p < 0.05), among the protocols (p < 0.05), and in the interaction between sealers and protocols (p < 0.05). AH Plus revealed the highest BS values among the sealers; the highest BS results for the sealers occurred with the specimens used with isopropyl alcohol, compared with ethanol and EndoVac.

Volume of sealer in the apical region of teeth filled by different techniques: a micro-CT analysis

Abstract The volume of sealer in the apical 1 mm of teeth filled using different techniques was evaluated by micro-commuted tomography (micro-CT). Sixty-four maxillary central incisors were prepared using NiTi rotary instruments. Teeth were randomly distributed into four groups according to root canal sealers (AH Plus, Endofill, Sealapex, and Sealer 26) and subdivided into two subgroups according to the filling techniques (active and passive lateral condensation; n = 8 each). Subsequently, teeth were examined using the 1174 SkyScan micro-CT device. Images were reconstructed using the NRecon software, and the sealer volume (mm3) in the apical region was analyzed using the two-way ANOVA and post-hoc Student-Newman-Keuls test (α = ٠.٠٥). The lowest volume of sealer was observed in teeth filled with Sealapex (0.100 ± 0.009) and Endofill (0.103 ± 0.010). The highest volume was observed in teeth filled with AH Plus (0.112 ± 0.008) and Sealer 26 (0.109 ± 0.018) (p > 0.05). Regarding the filling technique, a lower sealer volume was observed using the active lateral condensation technique compared with that using the passive lateral condensation technique (0.100 ± 0.010 vs. 0.111 ± 0.012) (p < 0.05). Therefore, the lowest volume of sealer was observed in teeth filled with Sealapex and Endofill using the active lateral condensation technique.

Evaluation of physico-chemical properties of Portland cements and MTA.

The purpose of this study was to evaluate the hydrogenionic potential and electrical conductivity of Portland cements and MTA, as well as the amount of arsenic and calcium released from these materials. In Teflon molds, samples of each material were agitated and added to plastic flasks containing distilled water for 3, 24, 72 and 168 h. The results were analyzed with a Kruskal-Wallis non-parametric test for global comparisons and a Dunn-Tukey test for pairwise comparisons. The results revealed no significant differences in the pH of the materials (p > 0.05). The electrical conductivity of the cements were not statistically different (p > 0.05). White non-structural cement and MTA BIO released the largest amount of calcium ions into solution (p < 0.05), while arsenic release was insignificant in all of the materials (p > 0.05). The results indicated that the physico-chemical properties of Portland cements and MTA were similar. Furthermore, all materials produced an alkaline environment and can be considered safe for clinical use because arsenic was not released. The electrical conductivity and the amount of calcium ions released into solution increased over time.

Time-dependent effects of chitosan on dentin structures

Complete debridement with smear layer removal are essential measures for achieving a successful outcome of root canal treatment. The aim of this study was to evaluate the effects of chitosan at different concentrations on the removal of the smear layer and on dentin structure after 3 and 5 min of application. Twelve recently extracted maxillary canine teeth were instrumented using the crown-down technique and irrigated with 1% sodium hypochlorite. The specimens were distributed according to the time and concentration of the final irrigating solution: G1: 0.1% chitosan for 3 min; G2: 0.2% chitosan for 3 min; G3: 0.37% chitosan for 3 min; G4: 0.1% chitosan for 5 min; G5: 0.2% chitosan for 5 min; G6: 0.37% chitosan for 5 min. All samples were prepared for SEM analysis. G1 exhibited removal of the smear layer, but not the smear plugs. G2 showed visible and open tubules with slight erosion of the peritubular dentin. Cleaning in G3 was similar to that in G2, however, the erosive effect was greater. There was expansion of the diameter of the tubules in G4; and in G5 and G6, there was severe erosion with deterioration of dentin surface. In conclusion, 0.2% chitosan for 3 min appeared to be efficient for removing the smear layer, causing little erosion of dentin.

Completo debridamento dos canais radiculares com a remoção da smear layer são medidas essenciais no sucesso do tratamento endodôntico. O objetivo deste estudo foi avaliar os efeitos da quitosana, em diferentes concentrações, na remoção da smear layer e na estrutura da dentina, após 3 e 5 min de aplicação. Doze dentes caninos superiores, recém extraídos, foram instrumentados pela técnica crown-down e irrigados com hipoclorito de sódio 1%. Os espécimes foram distribuídos em seis grupos conforme o tempo e a concentração da solução irrigante final: G1: quitosana 0,1% por 3 min; G2: quitosana 0,2% por 3 min; G3: quitosana 0,37% por 3 min; G4: quitosana 0,1% por 5 min; G5: quitosana 0,2% por 5 min; G6: quitosana 0,37% por 5 min. Todas as amostras foram preparadas para avaliação em MEV. Os resultados mostraram que o G1 apresentou remoção da smear layer, mas não da smear plug. O G2 mostrou túbulos visíveis e abertos com ligeira erosão da dentina peritubular. A limpeza no G3 foi semelhante à do G2, no entanto, o efeito erosivo foi maior. No G4 houve ampliação do diâmetro dos túbulos e no G5 e G6, severa erosão com deterioração da superfície dentinária. Concluiu-se que a quitosana 0,2% por 3 min foi eficiente na remoção da smear layer, ocasionando pequena erosão.

Endodontic treatment of dental formation anomalies / Tratamento endodôntico de anomalia dental de formação

PURPOSE: Dental fusion is defined as the union of two dental germs at some stage of their development. The aim of this article is to report the endodontic treatment of two clinical cases of dental fusion. CASE DESCRIPTION: In the first case, the patient was referred by an orthodontist for endodontic treatment of tooth 12, which was fused to 13. Surgical separation and later replacement of the involved elements in the dental arch was indicated. In the second case, the patient sought dental attendance due to spontaneous pain. In the radiographic exam, gemination in tooth 11 and fusion of 21 with a supernumerary tooth was observed. The fused teeth were endodontically treated, and patients were referred to other dental specialties to reestablish esthetics and function. CONCLUSION: The dentist must be able to diagnose, differentiate and treat these dental anomalies adequately, with the goal of maintaining patients' oral health.

OBJETO: Fusão dental é definida como sendo a união de dois germes dentais em algum momento do estágio de desenvolvimento. O objetivo desse artigo foi descrever o tratamento endodôntico de dois casos de fusão dental. DESCRIÇÃO DO CASO: No primeiro caso clínico, o paciente foi orientado pelo ortodontista a realizar tratamento endodôntico do dente 12, o qual estava fusionado ao dente 13. Foi realizada a separação cirúrgica dos elementos dentais e posterior reposicionamento no arco dental. No segundo caso clínico, o paciente procurou atendimento relatando dor espontânea na região anterior superior. Por meio do exame radiográfico, foi observado geminação do dente 11 e fusão do dente 21 com dente extranumerário. Em ambos os casos os dentes fusionados foram tratados endodônticamente e os pacientes encaminhados para restabelecimento da estética e função. CONCLUSÃO: O cirurgião dentista deve ter habilidade de diagnosticar, diferenciar e tratar adequadamente as anomalias dentárias, objetivando a manutenção da saúde oral dos pacientes.

Evaluation of physico-chemical properties of Portland cements and MTA

The purpose of this study was to evaluate the hydrogenionic potential and electrical conductivity of Portland cements and MTA, as well as the amount of arsenic and calcium released from these materials. In Teflon molds, samples of each material were agitated and added to plastic flasks containing distilled water for 3, 24, 72 and 168 h. The results were analyzed with a Kruskal-Wallis non-parametric test for global comparisons and a Dunn-Tukey test for pairwise comparisons. The results revealed no significant differences in the pH of the materials (p > 0.05). The electrical conductivity of the cements were not statistically different (p > 0.05). White non-structural cement and MTA BIO released the largest amount of calcium ions into solution (p < 0.05), while arsenic release was insignificant in all of the materials (p > 0.05). The results indicated that the physico-chemical properties of Portland cements and MTA were similar. Furthermore, all materials produced an alkaline environment and can be considered safe for clinical use because arsenic was not released. The electrical conductivity and the amount of calcium ions released into solution increased over time.

Avaliação da atividade antiinflamatória de AINES em tecido pulpar de ratos / Anti-inflamatory evaluation of AINES in rat´s pulps

O presente estudo avaliou a atividade antiinflamatória de antiinflamatórios não-esteroidais (AINEs)em tecido pulpar de ratos, por meio de microscopia óptica. Preparos cavitários foram realizados nos incisivossuperiores de 40 ratos para a indução de processo inflamatório pulpar. Os animais foram distribuídos aleatoriamenteem 5 grupos segundo a medicação administrada: G1 - celecoxib; G2 - rofecoxib; G3 - diclofenacode sódio; G4 - ibuprofeno e G5 - solução fisiológica (controle). A terapia com AINEs foi iniciada apo?s 24 horasda realização da exposição pulpar. Nos períodos de 1, 3, 5 e 7 dias após o início da terapia medicamentosa,2 animais de cada grupo foram sacrificados e tiveram seus dentes extraídos para a análise histológica dotecido pulpar. Os índices utilizados para avaliação qualitativa variaram de 1 (tecido quase regenerado) até6 (inflamação severa). Os dados foram analisados por meio de Análise de Variância e teste de Tukey. Verificou-se que todos os medicamentos testados foram capazes de reduzir a inflamação quando comparadosao grupo controle. O grupo tratado com celecoxib apresentou os melhores resultados na redução do quadroinflamatório (p<0,01), seguido pelo rofecoxib e ibuprofeno, que se comportaram de maneira estatisticamentesemelhantes entre si (p>0,01) e superiores ao diclofenaco de sódio (p<0,01).

This study evaluated the anti-inflammatory effect of non-steroids anti-inflammatory (AINEs) in rat´s pulps,behind optic microscopy. Cavities were done in maxillary incisors of 40 rats to induce pulp inflammatory.The animals were divided in 5 groups according to medication: G1 - celecoxib; G2 - rofecoxib; G3 - diclofenacode sódio; G4 - ibuprofeno and G5 - saline (control). The therapy was initialized 24 hours after the pulpexposition. In the periods of 1, 3, 5 and 7 days after the therapy, 2 animals of each group were sacrificedand had their teeth extracted to histological analysis of pulp tissue. The scores were 1 (healed tissue) to 6(severe inflammation). The data were evaluated by Variance analysis and Tukey´s test. It was verified thatall medicaments were capable to reduce inflammation compared to control group. The celecoxib group presentedthe best results in reduction of inflammation (p<0,01), followed by rofecoxib and ibuprofeno, whichwere statistically equal (p>0,01) and better than diclofenaco de sódio (p<0,01).

Estudo in vitro da infiltração marginal em dentes submetidos a três tipos de secção apical / In vitro study of apical leakage of root canals after different root apex resection techniques

Objetivo: O objetivo deste trabalho foi avaliar in vitro a infiltração marginal apical em dentes submetidos a três tipos de secção apical. Material e métodos: Foram utilizados 30 caninos superiores humanos, instrumentados no terço apical até a lima #40 e escalonados com broca de Gates-Glidden n.º 2, 3 e 4. Posteriormente, os elementos foram obturados pela técnica híbrida de Tagger de termoplastificação, utilizando-se o compactador de McSpadden, e divididos em três grupos distintos (n = 10). O primeiro grupo (GI) foi submetido ao corte apical de 3 mm com broca Endo Z em alta rotação. Os elementos do segundo grupo (GII) tiveram seus ápices desgastados em 3 mm com broca EndoZ em alta rotação, e os elementos do terceiro grupo (GIII) tiveram a região apical seccionada a 3 mm com o laser Er:YAG (500 pulsos, 12 pps a 300 mJ). Após sofrer as secções, cada grupo foi retroobturado com IRM e mantido em tinta nanquim por 5 dias. Decorrido esse tempo, os espécimes foram diafanizados, e a infiltração foi medida com auxílio de um microscópio de mensuração. Resultados: Os resultados mostraram haver diferença estatística significante (p < 0.01) entre GI e os demais grupos. Conclusão: O corte com broca Endo Z proporciona uma menor infiltração apical quando empregado nas apicectomias.

Objective: The aim of the present study was to evaluate in vitro apical arginal leakage of root canals after three root apex resection techniques. Material and methods: Thirty maxillary canines were prepared chemo-mechanically to a size 40 master apical file, and enlarged by using Gates Glidden burs 2, 3 and 4. Teeth were obturated by Tagger thermomechanical compaction technique and then divided into three groups (n = 10). The first group (GI) was 3 mm apicalresected with Endo Z in high speed handpiece. The specimens of second group (GII) were 3 mm apical weared with Endo Z, and the third group (GIII) had 3 mm apical resected with Er:YAG laser (500 impulse, 12 pps and 300 mJ energy). After the apical sections, IRM cement was placed into the root-end cavity and teeth of each group were immersed in India ink for 5 days and submitted to decalcification and clarifying or marginal apical microleakage visualization with microscope. Results: The results showed statistically difference (p < 0.01) between GI and the other groups. Conclusion: The root apex cut using Endo Z promotes the lowest values of microleakage when used in apicoectomy.

Smear layer removal and chelated calcium ion quantification of three irrigating solutions

The purpose of this study was to evaluate, by scanning electron microscopy (SEM), smear layer removal and quantify, by atomic absorption spectrophotometry, the amount of calcium ion present in the chelating solutions after their use. Sixteen extracted canines were instrumented using the step-back technique and were assigned to 3 groups according to the irrigating solution used: G1: 1 mL 17 percent EDTAC between each file; G2: 1 mL 17 percent CDTA; G3: 1 mL 17 percent EGTA. The solutions were collected after use. The teeth were cleaved longitudinally, evaluated under SEM and assessed for smear layer by blinded examiners and scored from 1 to 4. In order to quantify calcium ion release, the collected solutions were examined by atomic absorption spectrophotometry. Freidman's test was used for statistical analysis of SEM values and showed that canals irrigated with 17 percent EDTAC and 17 percent CDTA had significantly less smear layer throughout the canals than 17 percent EGTA (p<0.01). For analysis of the collected solutions, Tukey's test was used and showed that EDTAC and CDTA had a greater amount of calcium ions (22.8±7.54 and 60.6±20.67 æg/mL, respectively) compared to EGTA (70.5±14.2 æg/mL) (p<0.01). The association both methodologies may contribute to the understanding of how these solutions act in the root canal.

O objetivo do presente estudo foi avaliar a remoção de smear layer por meio da microscopia eletrônica de varredura (MEV) e quantificar a liberação de íons cálcio resultante da irrigação com as soluções quelantes estudadas, por meio da espectrofotometria de absorção atômica. Dezesseis caninos extraídos foram instrumentados com a técnica step-back e divididos em 3 grupos de acordo com a solução irrigadora utilizada: G1: 1 mL de EDTAC a 17 por cento entre cada lima; G2: CDTA a 17 por cento; e G3: EGTA a 17 por cento. As soluções foram coletadas após o uso. Os dentes foram secionados longitudinalmente e as raízes examinadas por MEV para verificação de smear layer nos terços por meio de escores (variando de 1 a 4), e avaliadas por três examinadores calibrados "cegos". Para quantificar a liberação de íons cálcio, as soluções coletadas foram avaliadas por espectrofotometria de absorção atômica. Com relação ao smear layer, o teste de Friedman evidenciou diferença estatisticamente significante (p<0,01) comparando-se o EGTA 17 por cento ao EDTAC 17 por cento e ao CDTA 17 por cento, sendo que os canais irrigados com estas duas soluções apresentaram menor quantidade de smear layer que aqueles irrigados com EGTA. As soluções de EDTAC 17 por cento (70,5±14,2 æg/mL Ca) e CDTA 17 por cento (60,6±20,67 æg/mL Ca) apresentaram maiores quantidades de íons cálcio (p<0,01) quando comparadas ao EGTA 17 por cento (22,8±7,54 æg/mL Ca). Desta forma, pode-se concluir que a associação destas metodologias pode contribuir para o entendimento da ação das soluções quelantes no interior dos canais radiculares.

Hábito de prescrição de antibióticos por especialistas em Endodontia

Introdução: a proposta do presente estudo foi determinar os hábitos da prescrição de antibióticos por especialistas em Endodontia, no que se refere ao tempo de uso,indicação e produto de primeira escolha. Métodos: um questionário com quatro perguntas foi entregue a 105 endodontistas do estado de São Paulo. Os resultados foram tabulados e comparados estatisticamente. Resultados: do montante dos entrevistados, 48,5% eram do sexo masculino e 51,5% do feminino. A amoxicilina foi o antibiótico de primeira escolha para 84,7% dos profissionais. No caso de pacientes alérgicos à penicilina, 47,6% dos entrevistados utilizam clindamicina e 42,8%, azitromicina. A grande maioria (79%) recomenda a administração do antibiótico por um período de 5 a 7 dias. Cerca de um terço dos entrevistados indica de forma inadequada a antibioticoterapia.Conclusão: a maior parte dos profissionais soube selecionar corretamente o antibiótico para pacientes alérgicos ou não à penicilina, assim como o tempo de administração. No entanto, ainda há profissionais que empregam inapropriadamente a antibioticoterapia, o que favorece a resistência bacteriana

Effect of different EGTA concentrations on dentin microhardness

The effect of 1 percent, 3 percent and 5 percent EGTA (ethylene glycol-bis-(b-amino-ethyl ether) N,N,N´,N´-tetra-acetic acid) on the microhardness of root dentin of the cervical third of human teeth was studied. Five newly extracted maxillary incisors were sectioned transversely at the cementoenamel junction, and the crowns were discarded. The roots were embedded in blocks of high-speed polymerized acrylic resin and cut transversely into 1-mm sections. The second section of the cervical third of the root of each tooth was sectioned and divided into four parts. Each part was placed on an acrylic disc that was used as a base for microhardness measurement. Fifty microliters of 1 percent EGTA, 3 percent EGTA, or 5 percent EGTA were applied to the dentin surface. Deionized and distilled water was used as control. Dentin microhardness was then measured with a load of 50 g for 15 s. Statistical analysis showed that the three concentrations of the chelating solution EGTA significantly reduced dentin microhardness when compared with water (ANOVA, p<0.01), and that there was a statistically significant difference among the three solutions (Tukey test, p<0.05)

Morphometric analysis of the effectiveness of different concentrations of sodium hypochlorite associated with rotary instrumentation for root canal cleaning

O presente estudo avaliou a capacidade de limpeza promovida pela técnica de instrumentação rotatória, com limas de níquel-titânio Profile .04, associado à soluções de hipoclorito de sódio (NaOCl), em diferentes concentrações, quando utilizados em canais com achatamento mésio-distal. Vinte dentes incisivos centrais inferiores humanos, unirradiculares, foram selecionados e divididos aleatoriamente em 4 grupos: Grupo I: NaOCl a 0,5%; Grupo II: NaOCl a 1%; Grupo III: NaOCl a 5%; Grupo IV: água destilada e deionizada. Após o preparo biomecânico, os dentes foram submetidos ao processamento histológico e análise morfométrica. A análise morfométrica mostrou que o NaOCl a 5% era estatisticamente mais eficiente na limpeza do canal radicular que o NaOCl a 0.5% e a água destilada, que apresentaram os mais baixos níveis de limpeza dos canais radiculares (p<0,01).

Avaliação da infiltração marginal apical de diferentes materiais retroobturadores / Evaluation of infiltration marginal apical level of different materials used for retrofilling

Introdução - O sucesso nas apicectomias está relacionado com o vedamento oferecido pelo material empregado nas retroobturações. O objetivo do presente estudo consiste em avaliar in vitro a infiltração marginal em retroobturações realizadas com 4 diferentes materiais obturadores: amálgama convencional, cimento de ionômero de vidro, IRM e resina composta. Materiais e métodos - Neste experimento foram utilizados 23 dentes caninos superiores. Após a instrumentação dos canais radiculares os dentes foram obturados pela técnica da condensação lateral utilizando o cimento obturador Sealer(R). Em seguida os dentes foram medidos da ponta da cúspide até o ápice, com auxílio de um paquímetro digital, recuando 2 mm da medida obtida, no qual se realizou a apicectomia. O preparo apical foi realizado utilizando-se a seqüência de pontas diamantadas do aparelho Nac Plus por 20 segundo a uma profundidade de 3 mm. Foram divididos aleatoriamente 4 grupos e 5 elementos, utilizando para cada grupo um dos materiais estudados. Realizada a retroobturação dos dentes forma imersos em nanquim e submetidos a diafanização para a visualização do nível de infiltração marginal apical após um período de 4 dias. A penetração do nanquim na região apical foi medida através do microscópio de mensuração. Resultados e conclusões - Os resultados evidenciaram que não houve diferença estatisticamente significante (p>0,05) entre o cimento de ionômero de vidro, IRM e resina composta, entretanto apresentaram diferença estatisticamente significante )p<0,05) em relação ao amálgama convencional

Instabilidade dimensional de materiais seladores provisórios à base de óxido de zinco-eugenol usados em endodontia / Dimensional instability of temporary sealing materials based on zinc-oxide-eugenol used in endodontics

Estudou-se "in vitro" a instabilidade dimensional de materiais seladores provisórios à base de óxido de zinco-eugenol. O método utilizado foi o de reação química entre uma solução indicadora - solução de sulfato de níquel a 5//e uma solução reveladora - solução alcoólica de dimetilglicoxima a 1//. Realizou-se ciclagem térmica (5º, 37º e 60ºC). Adicionou-se acetato de zinco ao óxido de zinco com o intuito de verificar a ação do mesmo na instabilidade dimensional. Os materiais foram divididos em dois grupos, um com selamento duplo (guta-percha + material selador) e outro sem selamento duplo. Conclui-se que nenhum dos materiais seladores provisórios testados, quer com selamento duplo, ou não, impediu a infiltração marginal submetido à ciclagem térmica. A adição de acetato de zinco ao óxido de zinco não foi efetivo para impedir a infiltração marginal

Study of the incidence of radicular grooves in maxillary incisors

The purpose of this investigation was to determine the incidence of radicular grooves in the upper incisors of 642 patients from the region of Ribeirão Preto, SP, Brazil. Radicular grooves, present in 3.9//of the patients, were found mainly on the lingual surface of the maxillary lateral incisor (3.0//). The maxillary central incisors showed radicular grooves on both the buccal and lingual surfaces with an incidence of 0.9//. It was not possible to relate the incidence of these grooves with race (white and negro) or with sex