Convenient model of hard tissue simulation for dental radiographic research and instruction.

BACKGROUND: The authors describe a technique for building an alternative jawbone phantom using dental gypsum and rice for research and dental radiology instruction. AIM: To investigate the potential of an alternative phantom to simulate the trabecular bone aspect of the human maxilla in periapical radiographs. METHODS: Half-maxillary phantoms built from gypsum-ground rice were exposed to X-rays, and the resulting images (experimental group) were compared to standardized radiographic images produced from dry human maxillary bone (control group) (n = 7). The images were blindly assessed according to strict criteria by three examiners for the usual trabecular aspects of the surrounding bone, and significant differences between groups and in assessment reliability were compared using Fisher's exact and kappa tests (α = 0.05). RESULTS: The differences in the trabecular aspects between groups were not statistically significant. In addition, interobserver agreement among observers was 0.43 and 0.51 for the control and experimental groups, respectively, whereas intraobserver agreement was 0.71 and 0.73, respectively. CONCLUSION: The tested phantom seemed to demonstrate potential for trabecular bone image simulation on maxillary periapical radiographs.

Palliative oral care in terminal cancer patients: Integrated review.

BACKGROUND: Palliative care (PC) aims to improve quality of life in patients and its families against life threatening diseases, through suffering's prevention and relief. It is the duty of the dental surgeon to possess the knowledge needed to treat a patient with little life span, in order to establish an adequate treatment plan for each situation. AIM: To synthesize the published evidence on oral conditions, impact, management and challenges in managing oral conditions among palliative patients. METHODS: Articles were selected from PubMed and Scopus electronic platforms, using a research strategy with diverse descriptors related to "palliative care", "cancer" and "oral health". The article's selection was done in two phases. The first one was performed by the main researcher through the reading of the abstracts. In the second phase two researchers selected eligible articles after reading in full those previous selected. Data was tabulated and analyzed, obtaining information about what is found in literature related to this subject and what is necessary to be approached in future researches about PC. RESULTS: As results, the total of 15 articles were eligible, being one a qualitative analysis, 13 (92.8%) clinical trials and one observational study. Of the 15 articles, 8 (53.4%) involved questionnaires, while the rest involved: one systematic review about oral care in a hospital environment, 2 oral exams and oral sample collection, one investigation of terminal patient's (TP) oral assessment records, 2 collection of oral samples and their respective analysis and one treatment of the observed oral complications. CONCLUSION: It can be concluded that the oral manifestations in oncologic patients in terminal stage are, oral candidiasis, dry mouth, dysphagia, dysgeusia, oral mucositis and orofacial pain. Determining a protocol for the care of these and other complications of cancer - or cancer therapy - based on scientific evidence with the latest cutting-edge research results is of fundamental importance for the multidisciplinary team that works in the care of patients in PC. To prevent complications and its needed to initial the dentist as early as possible as a multidisciplinary member. It has been suggested palliative care protocol based on the up to date literature available for some frequent oral complications in TP with cancer. Other complications in terminal patients and their treatments still need to have further studying.

Radiopacity Evaluation of Gutta-Percha Points in Thinner Samples than the ANSI/ADA Recommendation.

The aim of this study was to evaluate the radiopacity of different gutta-percha points (Endo Points®, Dentsply®, Tanari®, Meta®, Roeko® and Odous®) in samples of 1 mm thick as established by ANSI/ADA Specification #57 and ISO 6876/2001, in comparison with thinner samples. Twelve test specimens for each material, four for each thickness (0.3, 0.6, and 1 mm and diameter of 8 mm), were laminated and compressed between two polished glass plates until the desirable thickness. Digital radiographs were obtained along with a graduated aluminum stepwedge varying from 1 to 10 mm in thickness. The X-ray unit was set at 70 kVp, 10 mA and 0.4 s exposure time, at a focal distance of 36 cm. One calibrated observer quantified the average values of pixels with Adobe Photoshop® software. Data were analyzed using ANOVA and Tukey tests, at 5% significance level. At 0.6 and 1 mm thickness, all the tested materials showed radiopacity higher than 3 mm of aluminum (reference value). At 0.3 mm thickness, Odous and Tanari presented significantly less radiopacity than the reference, and the other materials showed similar radiopacity to the reference. The study concluded that the materials demonstrated different radiopacities and all had values above the minimum recommended by ANSI/ADA specification #57, being Odous and Tanari less radiopaque than the reference value in thinner samples (0.3mm).

Impact of Inorganic Xenograft on Bone Healing and Osseointegration: An Experimental Study in Rabbits.

PURPOSE: To evaluate if an inorganic graft applied before implant insertion interferes with osseointegration. MATERIALS AND METHODS: The bilateral mandibular incisors of 12 rabbits were extracted. One of the sockets was randomly filled with an inorganic xenogenic bone graft, whereas the remaining socket was allowed to heal naturally and served as a control. After 60 days, titanium implants were inserted into healing areas. The animals were killed 60 days after. Bone depositions were marked with fluorochrome oxytetracycline, alizarin, and calcein and evaluated using confocal laser scanning microscopy. Bone-to-implant contact (BIC) and bone area (BA) within the limits of the implant threads were analyzed. Data were compared statically by paired t tests, one-way ANOVA, and Bonferroni post hoc tests (α = 0.05). RESULTS: No differences between the control and experimental groups in bone deposition for each marker, in either the BIC or BA analysis were observed. The bone deposition marked by alizarin (14-21 days) was the highest, followed by oxytetracycline (0 and 7 days) and calcein (45 and 52 days) in both groups (P < 0.05). CONCLUSION: The bone healing or the course of osseointegration was not impaired by the use of an inorganic xenogenic graft before insertion of a titanium implant.

Radiopacity Evaluation of Gutta-Percha Points in Thinner Samples than the ANSI/ADA Recommendation

Abstract The aim of this study was to evaluate the radiopacity of different gutta-percha points (Endo Points®, Dentsply®, Tanari®, Meta®, Roeko® and Odous®) in samples of 1 mm thick as established by ANSI/ADA Specification #57 and ISO 6876/2001, in comparison with thinner samples. Twelve test specimens for each material, four for each thickness (0.3, 0.6, and 1 mm and diameter of 8 mm), were laminated and compressed between two polished glass plates until the desirable thickness. Digital radiographs were obtained along with a graduated aluminum stepwedge varying from 1 to 10 mm in thickness. The X-ray unit was set at 70 kVp, 10 mA and 0.4 s exposure time, at a focal distance of 36 cm. One calibrated observer quantified the average values of pixels with Adobe Photoshop® software. Data were analyzed using ANOVA and Tukey tests, at 5% significance level. At 0.6 and 1 mm thickness, all the tested materials showed radiopacity higher than 3 mm of aluminum (reference value). At 0.3 mm thickness, Odous and Tanari presented significantly less radiopacity than the reference, and the other materials showed similar radiopacity to the reference. The study concluded that the materials demonstrated different radiopacities and all had values above the minimum recommended by ANSI/ADA specification #57, being Odous and Tanari less radiopaque than the reference value in thinner samples (0.3mm).

Resumo O objetivo deste estudo foi avaliar a radipacidade de diferentes pontas de guta-percha (Endo Points®, Dentsply®, Tanari®, Meta®, Roeko® e Odous®) em amostras de 1 mm de espessura, conforme estabelecido pela especificação #57 da ANSI/ADA e pela ISO 6876/2001, em comparação com amostras de menor espessura. Doze amostras de cada material, quatro para cada espessura (0,3, 0,6 e 1 mm; 8 mm de diâmetro), foram confeccionadas por meio de laminação e compressão entre duas lâminas de vidro polidas, até a espessura desejada. Radiografias digitais foram obtidas juntamente com uma escala de alumínio graduada, com espessuras variando de 1 a 10 mm. O aparelho de raios X foi ajustado para 70 kVp, 10 mA, 0,4s de tempo de exposição, com distância focal de 36 cm. Um observador calibrado quantificou a média dos valores de pixel no programa Adobe Photoshop®. Os dados foram analisados utilizando os testes ANOVA e Tukey, com nível de significância de 5%. Nas espessuras de 0,6 e 1 mm, todos os materiais testados apresentaram radiopacidade maior do que 3 mm de alumínio (valor de referência). Na espessura de 0,3 mm, Odous e Tanari apresentaram radiopacidade significativamente menor que a referência, e as outras marcas mostraram radiopacidade semelhante à referência. Conclui-se que os materiais apresentaram diferentes radiopacidades e todos mostraram valores acima do mínimo recomendado pela especificação #57 da ANSI/ADA, sendo Odous e Tanari menos radiopacos do que o valor de referência nas amostras mais finas (0.3 mm).

Low-concentrated nonvital bleaching effect on bond strength of composite resin restorations / Efeito de clareadores não-vitais pouco concentrados sobre a força de cisalhamento de restaurações de resina composta

Objective: To investigate if short-term dentin bleaching with low-concentrated substances affects the bond strength of immediate resin composite restorations. Material and Methods: The buccal surfaces of fifty molar crowns were ground for dentin exposure and randomly assigned into 5 groups (n=10), according to the following treatments: sodium perborate + water; sodium perborate + 6% hydrogen peroxide; 6% hydrogen peroxide; 35% hydrogen peroxide (positive control), or no bleaching agent (negative control). The specimens were immediately restored with resin composite. Seven days after treatments, the shear bond test was performed in a universal test machine at a crosshead speed of 0.5 mm/min. Data were analyzed using ANOVA and Tukey’s HSD test (α = 0.05). Results: The shear bond strength mean values for the negative control group were higher than all experimental and positive control groups (p < 0.000), whose differences were not statistically significant (p > 0.05). Conclusion: Short-term dentin bleaching with sodium perborate+water, 6% hydrogen peroxide, or sodium perborate mixed with 6% hydrogen peroxide reduced the shear bond strength of immediate resin composite restorations.

Objetivo: Investigar se o clareamento rápido da dentina com substâncias de baixa concentração afeta a resistência de união ao cisalhamento de restaurações imediatas de resina composta. Material e Métodos: As superfícies vestibulares de cinquenta molares foram desgastadas para exposição da dentina e então aleatoriamente alocadas em 5 grupos (n = 10), de acordo com as substâncias clareadoras: perborato de sódio + água; perborato de sódio + peróxido de hidrogênio a 6%; peróxido de hidrogênio a 6%; peróxido de hidrogênio a 35% (controle positivo); ou nenhum agente clareador (controle negativo). Os espécimes foram imediatamente restaurados com resina composta. Sete dias após os tratamentos, testes de resistência ao cisalhamento foram realizados em uma máquina de ensaios universal a uma velocidade de cruzeta de 0,5 mm/min. Os dados foram analisados com os testes ANOVA e Tukey HSD (α = 0,05). Resultados: Os valores de resistência ao cisalhamento do grupo controle negativo foram maiores do que os dos grupos experimentais e controle positivo (p < 0,001), cujas diferenças não foram estatisticamente significativa (p > 0,05). Conclusão: Clareamentos dentinários rápidos com perborato de sódio, peróxido de hidrogênio 6% ou perborato de sódio misturado com peróxido de hidrogênio 6% reduziram a força de resistência ao cisalhamento de restaurações imediatas de resina composta.

Efetividade de um sistema rotatório para retratamento na remoção da obturação de canais radiculares / Effectiveness of rotatory system for retreatment in the root canal filling removal

O objetivo desse trabalho foi investigar a eficiência do sistema ProTaper Universal Re­tratamento (PUR) para a remoção do material obturador de canais radiculares durante o re­tratamento. Quarenta pré-molares inferiores extraídos foram tratados endodonticamente e,divididos aleatoriamente em dois grupos (n=20l, cada qual a ser desobturado com o sistema ProTaper Universal Retratamento (Gil ou com o método mecãnico/manual mediante o uso de brocas Gates Glidden e limas H (Gil - controle). Depois de desobturados, radiografias vestíbulo­-linguais e microscopias eletrônicas de varredura foram obtidas e avaliadas por dois examina­dores calibrados para a presença e distribuição dos resíduos de materiais obturadores. Os dados obtidos foram submetidos aos testes Exato de Fisher e aos testes de Kruskal Wallis e Mann­-Whitney post hoc, ambos ajustados ao intervalo de confiança de 95%. A proporção de resí­duos detectados radiograficamente nos espécimes do grupo I foi significativamente superior à do grupo II somente no terço apical (p=O.0489). As diferenças nas quantidades de resíduos re­manescentes detectados microscopicamente em ambos os grupos não foram estatisticamente significantes (p>O.05). O sistema Protaper Universal Retratamento foi tão efetivo quanto o método mecânico/manual para a remoção dos materiais obturadores de canais radiculares.

The aim of this study was to investigate the efficiency of Protaper Universal Retreatment (PU R) for the removal of root canal fillings during retreatment. Forty lower extracted premolars were endodontically treated and randomly divided into two groups (n=20l, each to be retrea­ ted with Protaper Universal Retreatment system (Gil or mechanical/manual method through Gates Glidden drills and H files (Gil - control group). After retreatment, buccolingual radiogra­phs and scanning electron micrographs were obtained and the resulting images were assessed by two calibrated examiners for the presence and quantity of root canal fillings residues. The data obtained were subjected to Fisher's Exact tests, Kruskal Wallis and Mann-Whitney post hoc tests, both adjusted to the 95% confidence interval. The proportion of residues detected in radiographic images of group 1 (PUR) was significantly higher than that of control group only in the apical third (p=O.0489). The differences in the amount of remaining residues detected microscopically in both groups were not statistically significant (p>O.05). The Protaper Univer­ sal Retreatment system was as effective as the echanical/manual method for the removal of root canal fillings from root canais.

Efficacy of an Organic Solvent and Ultrasound for Filling Material Removal

The aim of this study was to investigate whether a final rinse with Endosolv R® solvent and ultrasound resulted in cleaner root canal walls during endodontic retreatment. A total of 56 extracted premolar teeth were manually instrumented using a step-back flare technique and filled with gutta-percha and AH Plus sealer. After 9 months, the canals were retreated by removing the gutta-percha and sealer with ProTaper Universal Retreatment and rotary preparation with ProTaper Universal System up to an F5 file. As a final step, the teeth were randomly divided in 4 groups (n=14) and were subjected to passive ultrasonic irrigation (PUI) with either Endosolv R or distilled water. In the control groups, the irrigants were left undisturbed. Roots were cleaved and examined under scanning electron microscopy (SEM), and the amount of filling remnants on the canal walls was assessed by two calibrated examiners in a blinded fashion. Data were analyzed by the Kruskal-Wallis test and the Student-Newman-Keuls post hoc test (α=0.05). All groups presented filling debris in the three root canal thirds after retreatment. There were no significant differences between the groups or among the root canal thirds within each group (p>0.05). PUI with Endosolv R was not effective in the removal of filling debris from root canal walls.

O objetivo deste estudo foi investigar se a irrigação final com o solvente Endosolv R® e ultrassom promovia maior limpeza nas paredes do canal radicular durante o retratamento endodôntico. Um total de 56 dentes pré-molares extraídos foram instrumentados manualmente utilizandose a técnica escalonada e obturados com guta-percha e cimento AH Plus. Após nove meses, os canais foram retratados através da remoção da guta-percha e do cimento com Protaper Universal Retratamento e preparo rotatório com Sistema Protaper Universal até o instrumento F5. Após essa etapa, a amostra foi aleatoriamente dividida em quatro grupos (n=14) e os dentes submetidos à irrigação ultrassônica passiva (PUI) associada ao solvente Endosolv R ou à água destilada. Nos grupos controle, os irrigantes permaneceram sem agitação. Em seguida as raízes foram clivadas e examinadas sob microscopia eletrônica de varredura (MEV) para que a quantidade de material obturador remanescente nas paredes do canal fosse avaliada por dois examinadores treinados de forma cega. Os dados foram analisados através dos testes de Kruskal-Wallis e de Student-Newman-Keuls post hoc (α=0.05). Todos os grupos apresentaram resíduos de materiais obturadores nos três terços do canal radicular após o retratamento. Não houve diferenças significativas entre os grupos ou entre os terços dos canais em cada um dos grupos (p>0,05). Concluiu-se que PUI com Endosolv R não foi efetiva para a remoção de remanescentes de material obturador das paredes do canal radicular.

Efficacy of an organic solvent and ultrasound for filling material removal.

The aim of this study was to investigate whether a final rinse with Endosolv R® solvent and ultrasound resulted in cleaner root canal walls during endodontic retreatment. A total of 56 extracted premolar teeth were manually instrumented using a step-back flare technique and filled with gutta-percha and AH Plus sealer. After 9 months, the canals were retreated by removing the gutta-percha and sealer with ProTaper Universal Retreatment and rotary preparation with ProTaper Universal System up to an F5 file. As a final step, the teeth were randomly divided in 4 groups (n=14) and were subjected to passive ultrasonic irrigation (PUI) with either Endosolv R or distilled water. In the control groups, the irrigants were left undisturbed. Roots were cleaved and examined under scanning electron microscopy (SEM), and the amount of filling remnants on the canal walls was assessed by two calibrated examiners in a blinded fashion. Data were analyzed by the Kruskal-Wallis test and the Student-Newman-Keuls post hoc test (α=0.05). All groups presented filling debris in the three root canal thirds after retreatment. There were no significant differences between the groups or among the root canal thirds within each group (p>0.05). PUI with Endosolv R was not effective in the removal of filling debris from root canal walls.

Dissolução de cimentos endodônticos resinosos por solventes orgânicos em diferentes intervalos de tempo / Dissolution of resin-based root canal sealers by organic solvents at different time intervals

Objetivo: O objetivo deste estudo foi investigar se o tempo deexposição dos cimentos endodônticos resinosos a solventesorgânicos afeta sua solubilidade. Materiais e métodos: Moldes desilicona de condensação circulares padronizados (4,47 mm de largurapor 1,5 mm de altura) foram preenchidos com quatro cimentosendodônticos resinosos recém-misturados (Acroseal®, Epiphany®, AHPlus® e Sealer26®) e armazenados a 37°C por duas semanas (n=08).Depois de inspecionado, cada corpo-de-prova foi pesado três vezes eindividualmente imerso em Citrol®, Endosolv R®, hipoclorito de sódio a2,5% ou água destilada (controle) por 10 minutos, 02 horas e 24horas. Nos intervalos testados, a perda média de cada materialobturador imerso nos solventes foi determinada. Os dados foramanalisados estatisticamente com ANOVA de duas vias, Bonferronipost hoc e teste de Pearson (α=0,05). Resultados: O Endosolv R® foisignificativamente mais eficiente na dissolução do Sealer26® do que aágua destilada (grupo controle), óleo de laranjas e hipoclorito desódio 2,5%. O Citrol® e o hipoclorito de sódio 2,5% demonstrarammaior potencial para dissolver o cimento Sealer26® no intervalo de 24horas, quando comparados ao grupo controle. As diferenças de peso entre os cimentos imersos em hipoclorito de sódio 2,5% não semostraram estatisticamente significantes. A solubilidade foisignificativamente correlacionada com o tempo de exposição somentequando o Endosolv R® (+0,829) ou a água destilada (+0,441) foramempregados. Conclusão: A dissolução de cimentos à base de resinafoi afetada pelo intervalo de exposição e tipo de solvente orgânicoutilizado. Endosolv R® e períodos mais longos de exposiçãopromoveram maior solubilização dos cimentos de base resinosa testados.

Aim: The aim of this study was to investigate whether time exposureof resin-based root canal sealers to organic solvents affects theirsolubility. Materials and methods: Standardized circular siliconmoulds (4.47mm wide and 1.5mm high) were filled with four freshlymixed resin-based root canal sealers (Acroseal®, Epiphany®, AHPlus® and Sealer 26®) and stored at 37° for two weeks (n=8). Afterinspection, each sample was weighted thrice and individuallyimmersed in Citrol®, Endosolv R®, 2.5% sodium hypochlorite ordistilled water for 10, 120 and 1440 min. In the tested intervals, themean weight loss of each filling material immersed in solvents wasdetermined. Data were statistically analyzed by Two-wayANOVA, Bonferroni post hoc and Pearson tests (α=0.05). Results:Endosolv ® R was significantly more effective in dissolving Sealer26 ®than distilled water (control group), orange oil and 2.5% sodiumhypochlorite. Citrol® and 2.5% sodium hypochlorite showed thegreatest potential to dissolve Sealer26 ® within 24 hours, compared tothe control group. The weight losses between sealers immersed insodium hypochlorite 2.5% were not statistically significant. Solubilitywas significantly correlated with exposure intervals only whenEndosolv R® (+0,829) or double-distilled water (+0,441) wereapplied. Conclusion: Dissolution of resin-based root canal sealerswas affected by exposure interval and type of organic solvent used.Endosolv R® and longer exposure intervals promoted greatersolubilization of the resin-based sealers tested.

Influence of root canal sealer on the radiographic appearance of filling voids in maxillary single-rooted teeth.

OBJECTIVE: This study compared the influence of three epoxy resin-based sealers with distinct radiopacities on the observers' ability to detect root canal filling voids during radiographic analysis. MATERIAL AND METHODS: The root canals of 48 extracted maxillary canines were prepared and divided into three groups. Each group was laterally condensed with one sealer (AH Plus®, Acroseal® or a non-radiopaque sealer), and a longitudinal void was simulated in half of the specimens from each group (n=8). Buccolingual radiographs were obtained and randomly interpreted for voids by a radiologist and an endodontist in a blinded fashion. Teeth were cut and inspected under a microscope to confirm the position of void. Differences in sensitivity and specificity between groups and examiners were compared using the Fisher's Exact and McNemar tests, respectively (α=0.05). RESULTS: Significantly lower sensitivity levels (p<0.05) were observed in the coronal portion of fillings performed with both radiopaque sealers. Specificity values for Acroseal® were significantly higher (p<0.05) in the coronal and apical portions of fillings. CONCLUSIONS: The type of root canal sealer can affect the observers' ability to detect root canal filling voids during radiographic analysis of upper single-rooted teeth.

Adhesion of real seal to human root dentin treated with different solutions

The aim of this study was to evaluate the effects of different irrigants on sealer-dentin bond strength when using Real Seal. Thirty single-rooted teeth were divided into 3 groups. In one group, the teeth were irrigated with 3 mL of 2.5% NaOCl after each file change, flushed with 17% EDTA for 3 min and finally rinsed with 3 mL of 2.5% NaOCl. In the other two groups, rinse with NaOCl was replaced with 2% chlorhexidine gluconate (CHX) and 0.9% saline, respectively. Each root was sectioned transversally into apical, middle and coronal thirds to obtain 2-mm-thick slices. Each slice was filled with Real Seal and Resilon. Push-out test was used to analyze bond strength and failure modes were classified as adhesive, cohesive or mixed, according to SEM observations. The push-out test did not reveal any statistically significant difference (p>0.05) between the irrigants. However, the groups exhibited significantly different (p<0.05) bond strengths in terms of the root canal third. Higher bond strength was observed at the apical third when compared with coronal third, while middle third presented intermediary values. Fifteen specimens were analyzed by SEM (5 per group). Eleven specimens exhibited adhesive failures (5 in saline, 4 in NaOCl and 2 in CHX group); 2 cohesive failures were observed in the CHX group, and 1 mixed failure each was observed in the CHX and NaOCl groups. The tested irrigants did not influence the bond strength of Resilon and Real Seal to dentin. The apical third exhibited higher mean bond strengths and adhesive failures were predominant.

O objetivo deste estudo foi avaliar os efeitos de diferentes soluções irrigadoras na resistência adesiva do Real Seal à dentina radicular. Trinta dentes monorradiculares foram divididos em 3 grupos: Grupo 1 - os dentes foram irrigados com 3 mL de NaOCl 2,5% após cada troca de instrumento, irrigados com EDTA 17% por 3 min e lavagem final com NaOCl 2,5%. Nos Grupos 2 e 3, o NaOCl foi substituído por digluconato de clorexidina 2% (CHX) e solução salina 0,9%, respectivamente. Cada raiz foi seccionada transversalmente nos terços apical, médio e cervical para obter fatias de 2 mm de espessura. Cada slice foi obturado com Real Seal e Resilon. Teste de push-out foi usado para analisar a resistência adesiva e os padrões de falha foram classificados como adesiva, coesiva e mista de acordo com MEV. O teste de push-out não revelou diferença estatisticamente significante entre os irrigantes (p<0,05). Porém, os grupos exibiram diferentes valores de resistência adesiva de acordo com o terço radicular (p>0,05). Maior resistência adesiva foi observada na região apical quando comparado com o terço cervical, enquanto que o terço médio apresentou valores intermediarios. Quinze espécimes foram analisados através de MEV (5 por grupo). Onze espécimes exibiram falhas adesivas (5 no grupo da solução salina, 4 no grupo NaOCl e 2 na CHX); duas falhas coesivas foram observadas no grupo CHX e uma falha mista foi observada no grupo da CHX e uma no NaOCl. Os irrigantes testados não influenciaram a resistência adesiva do Resilon e do Real Seal à dentina radicular. O terço apical apresentou maior resistência adesiva e falhas adesivas foram predominantes para todos os grupos.

Influence of root canal sealer on the radiographic appearance of filling voids in maxillary single-rooted teeth

OBJECTIVE: This study compared the influence of three epoxy resin-based sealers with distinct radiopacities on the observers' ability to detect root canal filling voids during radiographic analysis. MATERIAL AND METHODS: The root canals of 48 extracted maxillary canines were prepared and divided into three groups. Each group was laterally condensed with one sealer (AH Plus®, Acroseal® or a non-radiopaque sealer), and a longitudinal void was simulated in half of the specimens from each group (n=8). Buccolingual radiographs were obtained and randomly interpreted for voids by a radiologist and an endodontist in a blinded fashion. Teeth were cut and inspected under a microscope to confirm the position of void. Differences in sensitivity and specificity between groups and examiners were compared using the Fisher's Exact and McNemar tests, respectively (α=0.05). RESULTS: Significantly lower sensitivity levels (p<0.05) were observed in the coronal portion of fillings performed with both radiopaque sealers. Specificity values for Acroseal® were significantly higher (p<0.05) in the coronal and apical portions of fillings. CONCLUSIONS: The type of root canal sealer can affect the observers' ability to detect root canal filling voids during radiographic analysis of upper single-rooted teeth.

Adhesion of Real Seal to human root dentin treated with different solutions.

The aim of this study was to evaluate the effects of different irrigants on sealer-dentin bond strength when using Real Seal. Thirty single-rooted teeth were divided into 3 groups. In one group, the teeth were irrigated with 3 mL of 2.5% NaOCl after each file change, flushed with 17% EDTA for 3 min and finally rinsed with 3 mL of 2.5% NaOCl. In the other two groups, rinse with NaOCl was replaced with 2% chlorhexidine gluconate (CHX) and 0.9% saline, respectively. Each root was sectioned transversally into apical, middle and coronal thirds to obtain 2-mm-thick slices. Each slice was filled with Real Seal and Resilon. Push-out test was used to analyze bond strength and failure modes were classified as adhesive, cohesive or mixed, according to SEM observations. The push-out test did not reveal any statistically significant difference (p>0.05) between the irrigants. However, the groups exhibited significantly different (p<0.05) bond strengths in terms of the root canal third. Higher bond strength was observed at the apical third when compared with coronal third, while middle third presented intermediary values. Fifteen specimens were analyzed by SEM (5 per group). Eleven specimens exhibited adhesive failures (5 in saline, 4 in NaOCl and 2 in CHX group); 2 cohesive failures were observed in the CHX group, and 1 mixed failure each was observed in the CHX and NaOCl groups. The tested irrigants did not influence the bond strength of Resilon and Real Seal to dentin. The apical third exhibited higher mean bond strengths and adhesive failures were predominant.

Long-term rabbits bone response to titanium implants in the presence of inorganic bovine-derived graft.

This study evaluated bone responses to titanium implants in the presence of an inorganic graft material. The bilateral mandible incisors of 24 rabbits were surgically extracted and one of the exposed sockets, chosen at random, was filled with an inorganic xenogenic bone graft (Gen-ox®), whereas the remaining socket was left to heal naturally and served as a control. After 60 days, titanium implants were inserted in the specific areas, and on days 0, 30, 60, and 180 after the implant insertions, six animals of each group were killed. Digital periapical radiography of implant region was obtained and vertical bone height (VBH) and bone density (BD) were evaluated by digital analysis system. In the undecalcified tissue cuts, bone-to-implant contact (BIC) and bone area (BA) within the limits of the implant threads were evaluated and compared statistically by means of two-way ANOVA and Tukey's test (ρ < 0.05). No significant differences were detected in VBH and BA, either between groups or between different experimental intervals. The BD was significantly higher in the experimental group than in the control group in all the intervals tested, but there were no significant differences by interval. The BIC was statistically lower in the control group on day 0; however, a significant increase was observed on days 60 and 180 (ρ < 0.05). The use of an inorganic xenograft prior to insertion of a titanium implant did not interfere with the course of osseointegration.

Surface Modifications on Aesthetically Restored Teeth following Home Bleaching with 16% Peroxide Carbamide.

OBJECTIVES: This clinical study evaluated the effects of a highly concentrated home-bleaching agent on the surface morphology of aesthetically restored teeth. METHODS: Specimens of human enamel and micro-hybrid composite resin were randomly adhered to the buccal side of right premolar and molar teeth of ten volunteers, who underwent a routine home-bleaching procedure with 16% carbamide peroxide on the upper jaw for 8 days. The mandibular unbleached specimens served as paired controls (n=10). Ultra-structural assessment of the sample was carried out by scanning electron microscopy, and the resulting images were blindly evaluated for topographical alterations. The differences between groups were calculated with the Mann-Whitney test adjusted at the 95% confidence interval. RESULTS: The bleached enamel presented significantly more morphological changes than the control group. The aspect of resin composite exposed to the whitening substance was statistically similar to that observed in the corresponding control group (P<.05). CONCLUSIONS: The occurrence of surface topography changes during home bleaching of aesthetically restored teeth with 16% carbamide peroxide was restricted to enamel.

Biomechanical and microscopic response of bone to titanium implants in the presence of inorganic grafts.

This study evaluated the biomechanical and microscopic response of previously grafted bone to titanium implants. The lower incisors of 16 rabbits were surgically extracted, and bilateral perforations communicating with the remaining sockets were created distally. A socket/perforation defect on each mandible was chosen at random to be immediately filled with a xenogenic graft, whereas the contralateral perforation was left to heal naturally and served as a paired control. After 60 days, titanium implants were installed in the previously operated areas. After periods of 2 and 6 months, the animals were killed, and the force necessary to retrieve implants as well as the bone-implant contact (BIC) and bone mass (BM) were quantified and statistically compared by 2-way analysis of variance and Tukey's test (α  =  .05). No significant differences in removal torque were observed, either by time or by treatment condition. Differences in BIC and BM between experimental and control groups were not statistically significant through the intervals studied (P < .05). The presence of a xenogenic graft did not influence the microscopic tissue response to titanium implants or fixation into newly formed or mature bone.

Bone crestal height and bone density after third-molar extraction and grafting: a long-term follow-up study.

The objective of this study was to evaluate the long-term influence of xenogenic grafts on bone crestal height and radiographic density following extraction of teeth. The right and left third lower molars of 22 patients were surgically extracted, and one randomly chosen socket was filled with a xenogenic graft (Gent-Tech). The contralateral molar was left to heal naturally, serving as a paired control. Digital intraoral radiographies were taken at surgery and 2, 6, and 24 months after, to evaluate bone density (BD) and alveolar bone crest to cementoenamel junction distance. The data obtained were subjected to two-way analysis of variance and Tukey's test (α = 0.05). The significant decrease in cementoenamel junction distance observed for both groups was limited to the first 6 months. BD values increased significantly in the first 6 months, with no alterations observed up to 24 months for both groups. BD was higher for the experimental group at all time points (p < 0.05). Socket grafting with the xenogenic materials tested did not changed bone crestal height and bone radiographic density in the long term.

Effect of calcium hydroxide-based dressing on apical sealing in immature teeth filled with MTA / Efeito da medicação à base de hidróxido de cálcio no selamento apical de dentes imaturos obturados com MTA

OBJECTIVES: To evaluate the effects of a calcium hydroxide-based intracanal dressing on the initialapical adaptation and leakage of fillings performed with mineral trioxide aggregate (MTA) in teeth withopen apices. STUDY DESIGN: A total of 24 canals were manually prepared and randomly divided intotwo groups (n = 12). In the experimental group, root canals were dressed with calcium hydroxide-basedpaste for 21 days; in the control group, no medication was applied prior to the filling of root canalswith mineral trioxide aggregate. Apical sealing was evaluated on the basis of rhodamine B penetrationand the detection of microscopic apical defects at the filling interface (SEM). The data obtained werecompared by means of t- and Fisher’s Exact tests (á = 0.05). RESULT S: The difference in mean dyeleakage between the experimental (5.03±1.97 mm) and control (4.14±1.13 mm) groups was not statisticallysignificant (ñ < 0.05). The number of microscopic fissures at the experimental group interface (2/12)was significantly lower than that observed for the control group (9/12) (ñ < 0.05). CONCLUSIONS:The use of a calcium hydroxide-based intracanal dressing did not interfere with the initial apical sealingof immature teeth filled with MTA.

OBJETIVOS: Avaliar os efeitos da medicação intracanal à base de hidróxido de cálcio sobre a adaptação apical inicial e selamento de obturações realizadas com agregado de trióxido mineral (MTA) em dentes com ápice aberto. PLANEJAMENTO DO ESTUDO: Um total de 24 canais foram manualmente preparados e aleatoriamente divididosem dois grupos (n = 12). No grupo experimental, canais radiculares foram preenchidos com pasta à base de hidróxido de cálcio por 21 dias; no grupo controle, nenhuma medicação foi aplicada antes da obturação dos canais com agregado de trióxido mineral. O selamento apical foi avaliado com base na penetração de rodamina B e na detecção microscópica de defeitos apicais na interface das obturações (MEV). Os dados obtidos foram comparados por intermédio dos testes “t” e Exato de Fisher (α = 0,05). RESULTADOS: A diferença nos níveis médios de infiltraçãoentre os grupos experimental (5.03±1.97 mm) e controle (4.14±1.13 mm) não se mostrou estatisticamente significante (ρ < 0,05). O número de fendas microscópicas na interface das obturações do grupo experimental (2/12) apresentou-se estatisticamente inferior ao detectado para o grupo controle (9/12) (ρ < 0,05). CONCLUSÕES: O uso de medicação intracanal à base de hidróxido de cálcio não interferiu no selamento apical inicial de dentes imaturos obturados com MTA.

Radiographic analysis of root canal fillings: influence of two sealers on the perception of voids.

The aim of this ex vivo was to investigate if two radiopaque root canal sealers with different formulations would influence the radiographic perception of root canal fillings. The root canals of 48 extracted maxillary canines were prepared and randomly assigned to 3 groups of 16 specimens each. In each group, the root canals were filled by lateral condensation of gutta-percha and one of the tested sealers: Endométhasone, Sealer 26, or a non-radiopaque sealer. A through-and-through void was simulated in half of the specimens from each group (n=8). The buccolingual radiographic images obtained were randomly interpreted for voids existence by a radiologist and an endodontist. The differences in sensitivity and specificity between groups and examiners were compared using, respectively, Fisher's Exact and McNemar tests at 5% significance level. Both radiopaque sealers caused a significant decrease in sensitivity at the coronal part of fillings. The use of Endométhasone increased specificity values for both coronal and apical portions of the root canal fillings. In conclusion, the tested sealers influenced the radiographic perceptions of laterally condensed root canal fillings in a different way.