Influence of design implant and apical depth in post-extraction sockets: an in vitro simulated study.

BACKGROUND: Implant design and apical stability are principal parameters involved in achieving successful primary stability. Using polyurethane models to simulate post-extraction sockets, we investigated the effects of using differing blade designs on the primary stability of tapered implants and the impact of apical depth. METHOD: Six polyurethane blocks were used to simulate post-extraction pockets. One of the implants presented self-tapping blades (Group A), while the other (Group B) did not. Seventy-two implants were placed at 3 different depths (5 mm, 7 mm, and 9 mm), and a torque wrench was used to measure the stability of the implants. RESULTS: When evaluating the implants (placed at 5 mm, 7 mm, and 9 mm apical to the socket), we observed that the torque of the Group B implants was higher than that of Group A implants (P < 0.01). At the 9-mm depth, there was no difference between the groups (Drive GM 34.92 Ncm and Helix GM 32.33 Ncm) (P > 0.001), and considering the same implant groups, those placed at 7-mm and 9-mm depths presented higher torques (p < 0.01) than those placed at 5-mm (p > 0.01). CONCLUSION: Considering both groups, we concluded that an insertion depth of greater than 7 mm is needed for initial stability, and in situations involving reduced supportive bone tissue or low bone density, a non-self-tapping thread design improves implant stability.

Distance learning during social seclusion by COVID-19: Improving the quality of life of undergraduate dentistry students.

BACKGROUND: Social isolation is ongoing worldwide with the aim to stem the spread of the novel coronavirus SARS-CoV-2 responsible for the COVID-19 pandemic. However, social isolation leads to significant psycho-emotional changes. This study aimed to assess the effect of distance education (DE) activities implemented due to social isolation, on the quality of life of undergraduate dentistry students. METHOD: An e-questionnaire (Google Forms® ) was administered to identify specific DE activities after social isolation and included the World Health Organization Quality of Life (WHOQOL)-Bref questionnaire. The e-questionnaire was sent 14 days after the initiation of social isolation, remaining available for 48 hours. Cronbach's alpha and the means of the quality-of-life domains were calculated and analysed using the Friedman/Dunn and Spearman's correlation tests. After ranking, chi-squared and Fisher's exact tests plus multinomial logistic regression were performed (SPSS, P < .05). RESULT: There was an excellent internal consistency of WHOQOL-Bref (α = 0.916), and the mean quality of life (0-100) was 70.66 ± 12.61. The psychological domain was the most affected (P < .001). The social domain exhibited the weakest correlation with overall quality of life (P < .001, r = 0.688). The use of the Internet, cell phones and streaming media increased, although all students had DE activities. In the multivariate analysis, attending virtual meetings (P = .028) and performing DE activities in an office/study room (P = .034) were significantly associated with good quality of life. CONCLUSION: Facing social isolation never previously experienced by this generation, undergraduate dentistry students are at risk of reduced quality of life. Therefore, performing DE activities through devices with teacher-student interaction is a key coping tool.

A novel antimicrobial orthodontic band cement with in situ-generated silver nanoparticles.

OBJECTIVE: To develop an antimicrobial orthodontic band cement for the prevention of white spot lesions using a novel process that generates silver nanoparticles (AgNP) in situ. MATERIALS AND METHODS: Twenty-seven groups of AgNP-loaded Opal Band Cement (OBC) and two control groups were formulated with varying concentrations of additional benzoyl peroxide (0.5, 1.0, 1.5, or 2.0 wt%) and 2,2-(p-Tolylimino) diethanol (0.5 or 1 wt%). Rockwell15T hardness and near-infrared FTIR were used to assess degree of cure, three-point bending was used to determine modulus and ultimate transverse strength (UTS), and Ag(+) ion release was measured for up to 4 months in vitro using atomic absorption spectroscopy. Antimicrobial activity against Streptococcus mutans and Lactobacillus acidophilus was tested in vitro by counting colony-forming units for up to 28 days. Biocompatibility was evaluated following ISO specifications 7405 (2008), 10993-3 (2003), 10993-5 (2009), and 10993-10 (2010). RESULTS: Most of the experimental groups had hardness, modulus, and UTS values similar to those of the control group. Ag(+) ion release was observed for all AgNP-loaded groups for up to 4 months. Increase in Ag loading increased Ag(+) ion release and in vitro antimicrobial effect. The biocompatibility of the optimal AgNP-loaded OBC was comparable to that of negative controls. CONCLUSION: A novel antimicrobial orthodontic band cement was developed that has comparable mechanical properties to controls, controlled and sustained Ag(+) ion release, significant bacterial inhibition in vitro, and excellent biocompatibility.

Transurgical restoration in the absence of attached gingiva. A case report.

A 45-year-old woman needing a Class V restoration in a mandibular molar without attached gingiva is presented. In an interdisciplinary intervention, transurgical restoration was accomplished, including flap surgery with a slight ostectomy and restoration with a bonding system and a resin composite. A 1-year clinical evaluation showed satisfactory marginal adaptation and restoration contour associated to gingival tissue health.

Influência de soluções irrigadoras e de materiais obturadores na infiltração apical ­ análise pelo método de filtração de fluidos / Influence of irrigating solutions and of root filling materials on apical leakage ­ Fluid filtration method analysis

Objetivo: avaliar, por meio do método de filtração de fluidos, a influência da solução irrigadora e diferentes associações de materiais obturadores na infiltração apical. Métodos: foram utilizados 112 pré-molares inferiores extraídos, divididos em dois grupos controle (n=8) e oito grupos experimentais (n=12), de acordo com a solução irrigante: hipoclorito de sódio (H), vinagre de maçã (V), e, de acordo com o material obturador, guta-percha/AH Plus (GA), Resilon/Epiphany (RE), guta-percha/Epiphany (GE) e Resilon/AH Plus (RA). Os canais radiculares foram instrumentados e obturados pela técnica híbrida de Tagger. Em seguida, os canais foram desobturados nos terços médio e cervical, permanecendo apenas 4 mm do terço apical para a análise da infiltração pelo método de filtração de fluidos. Os dados foram analisados, estatisticamente, pelo teste de Kruskal-Wallis, sendo considerado significante quando P<0,05. Resultados: as médias obtidas de infiltração apical (µL/min) nos grupos foram: H/GA (0,03 ± 0,09), V/GA (0,04 ± 0,05), H/RE (0,06 ± 0,13), V/RE (0,10 ± 0,20), H/GE (0,08 ± 0,18), H/GE (0,16 ± 0,21), H/RA (0,40 ± 0,63) e V/RA (0,57 ± 1,13). Não foi observada diferença estatística quanto às soluções de irrigação aplicadas (P>0,05). No entanto, em relação aos materiais obturadores, verificou-se que os grupos obturados com a associação Resilon/AH Plus apresentaram, significativamente, maior infiltração que os demais grupos (P<0,05). Conclusões: a infiltração apical foi influenciada apenas pelos materiais obturadores, independentemente da solução de irrigadora.

Objective: to evaluate by fluid filtration method, the influence of the irrigating solution and different root filling materials associations in the apical leakage. Methods: One hundred-twelve lower premolars extracted were divided in 2 control groups (n=8) and 8 experimental groups (n=12), according to the irrigation solution; sodium hypochlorite (H), apple vinegar (V), and according to the root canal filling material, gutta-percha/AH Plus (GA), Resilon/Epiphany (RE), gutta-percha/Epiphany (GE), Resilon/AH Plus (RA). The roots canals were instrumented and filled by Tagger's hybrid technique being removed from the filling material, having remained only 4 mm of apical root third to analyze the leakage through fluid filtration method. Data were analyzed by Kruskal-Wallis test and P<0.05 was considered significant. Results: The apical leakage means (µL/min) observed in the groups were, H/GA (0.03 ± 0.09), V/GA (0.04 ± 0.05), H/RE (0.06 ± 0.13), V/RE (0.10 ± 0.20), H/GE (0.08 ± 0.18), H/GE (0.16 ± 0.21), H/RA (0.40 ± 0.63) e V/RA (0.57 ± 1.13). It was observed no statistical difference regarding the irrigation solutions applied (P>0.05), although the groups irrigated with sodium hypochlorite showed the best results. However, regarding the root canal filling material used, it was verified that the groups filled with Resilon/AH Plus association (H/RA e V/RA) have shown leakage higher significantly than other groups (P<0.05). Conclusion The apical leakage was influenced only by the root filling materials, regardless the irrigation solution.

Effects of reducing agents on birefringence dentin collagen after use of different endodontic auxiliary chemical substances.

INTRODUCTION: The aim of this study was to evaluate the effect of 10% ascorbic acid or 10% sodium ascorbate on organic matrix collagen of bovine dentin root canal walls after irrigation with 5.25% sodium hypochlorite (NaOCl), 17% ethylenediaminetetraacetic acid (EDTA), or 0.9% sodium chloride. METHODS: Eighty bovine incisors were randomly divided into 8 groups (n = 10): group 1, 0.9% sodium chloride (control); group 2, 5.25% NaOCl + 17% EDTA (NaOCl + EDTA); group 3, 5.25% NaOCl + 17% EDTA + 10% ascorbic acid (NaOCl + EDTA + AA); group 4, 5.25% NaOCl + 17% EDTA + 10% sodium ascorbate (NaOCl + EDTA + SA); group 5, 5.25% NaOCl (NaOCl); group 6, 17% EDTA; group 7, 10% ascorbic acid (AA); and group 8, 10% sodium ascorbate (SA). Teeth were chemomechanically prepared, submitted to histologic processing, and stained with Sirius Red dye to be analyzed under polarized light microscopy. Absorbance assay was also performed to confirm the loss of collagen. RESULTS: NaOCl + EDTA and NaOCl groups presented a significantly different birefringence pattern compared with the control group (P < .05). The measurement of the optical retardations of NaOCl + EDTA + SA indicated that this group was not statistically different from the control group. Although the measurement of the optical retardations of NaOCl + EDTA + AA was statistically different from the control group, the results were significantly higher than for NaOCl + EDTA. The birefringence of EDTA, AA, and SA groups was not statistically different from that of control group. The absorbance assay of NaOCl + EDTA and NaOCl groups confirmed the loss of collagen (P < .05). CONCLUSIONS: It is possible to conclude that 5.25% NaOCl, whether associated or not with 17% EDTA, causes birefringence alterations and loss of dentin collagen. These alterations reduced the ability of Sirius Red to bind with collagen fiber molecules. The reductions in the optical retardation values could be reversed by the application of either 10% ascorbic acid or 10% sodium ascorbate after 5.25% sodium hypochlorite and 17% EDTA irrigation.

Structural analysis of bovine root dentin after use of different endodontics auxiliary chemical substances.

INTRODUCTION: The use of chemical substances in endodontics during chemical-mechanical preparation may alter the structure of dentin, mainly collagen, which contributes considerably to the mechanical properties of this structure. This study evaluated the effect of different auxiliary chemical substances during endodontic treatment in root canal walls by implementing polarized light microscopy (PLM) and scanning electron microscopy (SEM). METHODS: Sixty bovine incisors were randomly divided into six groups (n = 10): G1, 5.25% NaOCl + 17% EDTA; G2, 2% chlorhexidine (CHX) gel; G3, 5.25% NaOCl; G4, 17% EDTA; G5, 2% CHX + 17% EDTA; and G6, 0.9% sodium chloride solution (control). Teeth were chemomechanically prepared and fractured into two fragments. One fragment was used for PLM, and the other was used for SEM analysis. RESULTS: Groups treated with 5.25% NaOCl, whether associated or not associated to 17% EDTA, presented a significantly different birefringence pattern compared with the control group. The results revealed that groups irrigated with 2% CHX and EDTA, independently or combined, did not present any significant differences compared with the control group. SEM analysis showed structural alterations of the root canal inorganic matrix for all groups that used 17% EDTA. CONCLUSIONS: It is possible to conclude that 5.25% NaOCl, whether associated or not associated with 17% EDTA, causes alterations in the dentin collagen. The obtained SEM images revealed demineralization areas for groups that used 17% EDTA alone or associated with other substances.

In vitro penetration of two cements into artificially created lateral canals / Análise in vitro da obturação de canais laterais simulados utilizando dois tipos de cimentos

Objective: The aim of this study was to assess the penetration of two obturation materials, Guta-percha (Konne Ind. e Com. Ltda., Belo Horizonte, Brazil) / Pulp Canal Sealer (Kerr Sybron, Romulus, USA) and Resilon (Resilon Research LLC, Madison, CT, USA) / Epiphany (Pentron Clinical Technologies, Wallingford, CT, USA), into artificially created lateral canals. Methods: Twenty upper, single-rooted human teeth with full or partial crown, straight root and radiograph suggesting one root canal were selected. Six lateral canals were created on each root, two on each third. The teeth were then divided randomly into 2 groups of 10 teeth each. The continuous wave of condensation technique was used to obturate all canals. After obturation, the roots were sectioned cross-sectionally into 3 segments with a diamond disc to expose the lateral canals. The segments were fixed in a fast curing epoxy resin and micrographs of the lateral canals magnified 20 times were taken. The software Carnoy 2.0 was then used to measure obturation material penetration into each lateral canal. The data were treated by the non-parametric Kruskal-Wallis test. Results: The extent of the lateral canals penetrated by the two obturation materials did not differ significantly in any of the root thirds (p>0.05). Conclusion: Both obturation materials, Guta-percha (Konne Ind. e Com. Ltda., Belo Horizonte, Brazil) / Pulp Canal Sealer (Kerr Sybron, Romulus, USA) and Resilon (Resilon Research LLC, Madison, CT, USA) / Epiphany (Pentron Clinical Technologies, Wallingford, CT, USA), presented good penetration, which did not differ significantly.

Objetivo: Avaliar a capacidade de selamento de canais laterais simulados frente a dois sistemas obturadores: Guta-percha (Konne Ind. e Com. Ltda., Belo Horizonte, Brasil) e cimento Pulp Canal Sealer (Kerr Sybron, Romulus, USA) e Resilon (Resilon Research LLC, Madison, CT, USA) com Epiphany (Pentron Clinical Technologies, Wallingford, CT, USA). Métodos: Foram selecionados 20 dentes humanos unirradiculares superiores, com coroas totais ou parcialmente íntegras, raízes retas e imagem radiográfica sugestiva de um canal. Foram confeccionados seis canais laterais, com a utilização de uma broca Long Neck ½ (Dentsply-Maillefer, Ballaigues, Suíça), em cada espécime, sendo igualmente distribuído nos 3 terços radiculares. Posteriormente, os dentes foram divididos aleatoriamente em 2 grupos de 10 dentes. A técnica de obturação utilizada foi a Onda Contínua de Condensação. Após as obturações, as raízes foram seccionadas transversalmente com um disco de diamante em 3 segmentos, que possibilitou a visualização dos canais laterais. Os segmentos foram incluídos em uma resina epóxica de presa rápida. As imagens dos terços radiculares inseridos em resina epóxica foram capturadas em lupa estereomicroscópica, com aumento de 20 vezes. Foram realizadas medições lineares das obturações em cada um dos canais dos diferentes segmentos dos dentes de cada grupo através do programa Carnoy 2.0. Os dados foram submetidos à análise estatística utilizando o teste não paramétrico de Kruskall-Wallis. Resultados: A análise dos resultados demonstrou não haver diferença estatística no escoamento entre os materiais obturadores e seus terços apicais, médios e cervicais (p > 0,05). Conclusão: Concluiu-se que os dois materiais obturadores, apresentaram um bom escoamento nos canais laterais, não havendo diferença estatística entre eles.

Effect of the smear layer on the filling of artificial lateral canals and microleakage

Aim: To evaluate the influence of the smear layer on the filling and prevention of microleakage in artificial lateral canals after use of different irrigating solutions. Methods: Two lateral canals were produced in 44 human dental roots with drills of 0.1 mm in diameter. The roots were divided in 4 groups according to the irrigation protocol: GI - 0.9% saline solution (control); GII - 2.5% sodium hypochlorite + 17% EDTA; GIII - 2% chlorhexidine gel + 17% EDTA; GIV - 2% chlorhexidine solution + 17% EDTA. Four roots were used as negative (n=2) and positive (n=2) controls. Lateral condensation technique and AH Plus were used to fill the root canals. Digital buccolingual radiographs were exposed and after the sealer had set, the roots were immersed in Indian ink dye and then cleared in methyl salicylate. The extent of filling and microleakage were measured and the values analyzed statistically. Results: No difference was found in the percentage of filling and microleakage among the groups, regardless of the location of the artificial lateral canals and the irrigation protocol used. Twenty percent of lateral canals produced no radiographic images, but their filling was confirmed using the clearing technique. Conclusions: The presence or absence of the smear layer did not affect the filling ability and the prevention of microleakage in artificial lateral canals.

A capacidade de dissolução tecidual do hipoclorito de sódio é realmente confiável? Um estudo in vitro e ex vivo / The sodium hipochlorite tissue dissolution ability during endodontic treatment can really be trusted? An in vitro and ex vivo study

Objetivo: o objetivo desse estudo foi avaliar o efeito de dissolução tecidual do hipoclorito de sódio (NaOCl), em diferentes concentrações, na porção apical da raiz mesial de molares inferiores humanos com istmos, e avaliar o tempo de dissolução tecidual de tecido pulpar bovino em contato direto com diferentes concentrações e volumes de hipoclorito de sódio. Métodos: foi realizada uma investigação histológica em 30 raízes mesiais de molares inferiores humanos, as quais foram instrumentadas com o sistema Mtwo e irrigadas com NaOCl a 2,5% e a 5,25%. Solução salina foi utilizada como controle. Cada amostra foi submetida ao processamento histológico, e as imagens foram analisadas com o software ImageJ. A porcentagem de área ocupada pelo tecido foi calculada dividindo-se a área do tecido pela área dos canais. Os dados foram analisados por meio de análise de variância com o teste de Tukey (p < 0,05). O tempo de dissolução foi analisado por meio da imersão de tecido pulpar bovino em diferentes volumes em concentrações de 2,5% e 5,25% de solução de NaOCl. Resultados: não foi encontrada diferença significativa entre as diferentes concentrações de NaOCl na investigação histológica. Nenhuma das substâncias foi capaz de realizar a completa limpeza dos istmos. Adicionalmente, foi encontrada uma maior taxa de dissolução para o tecido pulpar bovino na concentração de 5,25% de NaOCl, além de uma redução do tempo de dissolução para volumes maiores. Conclusão: o NaOCl é eficaz na dissolução de tecidos quando em contacto direto; no entanto, o NaOCl, mesmo em altas concentrações, não foi competente para dissolver restos de tecido pulpar em istmos radiculares durante o tratamento endodôntico