Cone Beam Computed Tomography Assessment of the Volume of Dental Tissue Removed During Endodontic Access

Introduction: The purpose of this study was to determine the volume of dental tissue removed during endodontic access preparation with cone-beam computed tomography (CBCT) comparing two different software. Methods and Materials: CBCT images of 20 teeth were obtained before and after endodontic access performed with spherical and conical diamond burs. The images were taken with i-CAT Precise system with 0.25 mm voxel size. Digital Imaging and Communications in Medicine (DICOM) images were loaded on two different software programs (Materialise® and InVersalius®), and a 3D reconstruction of the CBCT images was performed on both programs. The baseline volume (BV), and the final volume (FV) were obtained, and the lost tissue volume (LV) was calculated using the formula: LV=BV-FV. The t-test was used to compare initial and final volumes and also to compare the two programs, using a significance level of 5%. Results: The volumetric data calculated for the MaterialiseÒ and the InVesaliusÒ programs were, respectively: BV-mean of 441.79±85.08 mm3 and 442.01±84.83 mm3; FV-mean of 426.75±83.88 mm3 and 426.94±83.75 mm3; LV-mean of 15.04±4.32 mm3 and 15.07±4.16 mm3. No statistically significant difference was found in the volumes calculated by either program for initial, final, or removed tissue (P>0.05). However, there was a significant difference between the BV and LV calculated on the same program (P<0.05). Conclusion: Our in vitro study showed that CBCT was able to determine the volume of dental tissue removed in the endodontic access preparation of extracted human teeth, regardless of the software program used

Influência do iodofórmio no potencial antimicrobiano do hidróxido de cálcio

The purpose of this research was to verify the influence of Iodoform on antimicrobial potential of calcium hydroxide. S. aureus, E. faecalis, P. aeruginosa, B. subtilis, C. albicans were the biological indicators. The substances tested were: calcium hydroxide + saline; calcium hydroxide + Iodoform + saline; Iodoform + saline. For the agar diffusion test, 18 Petri plates with 20 ml of BHI agar were inoculated with the microbial suspensions. Fifty-four cavities were made and filled with the substances tested. The diameters of microbial inhibition were then measured. In direct exposure test, 162 #50 sterile absorbent paper points were immersed in the experimental suspensions for 5 min, and covered with the pastes. At intervals of 24, 48 and 72 hours, the paper points were immersed in 10 ml of Letheen Broth, followed by incubation at 37°°C for 48h. Microbial growth was evaluated by turbidity of the culture medium. A 0.1 ml inoculum obtained from the Letheen Broth was transferred to 7 ml of BHI, and incubated at 37°°C for 48h. Bacterial growth was again evaluated by turbidity of the culture medium. The calcium hydroxide associated with the saline or the iodoform plus saline showed antimicrobial effectiveness in both experimental methods. The iodoform paste presented antimicrobial ineffectiveness for the agar diffusion test on all biological microorganisms and for the direct exposure test on B. subtilis and on the mixture.Objetivo deste estudo foi verificar a influência do Iodofórmio no potencial antimicrobiano do hidróxido de cálcio. S. aureus, E. faecalis, P. aeruginosa, B. subtilis, C. albicans foram os indicadores biológicos. As substâncias testadas foram: hidróxido de cálcio + solução salina; hidróxido de cálcio + iodofórmio + solução salina; iodofórmio + solução salina. Para o teste de difusão em ágar, 18 placas de Petri contendo 20 ml de ágar BHI foram inoculadas com as suspensões microbianas. Cinqüenta e quatro cavidades foram feitas e preenchidas com as substâncias testadas. Os diâmetros da inibição microbiana foram então mensurados. No teste de exposição direta, 162 pontas de papel absorvente número 50 esterilizadas foram imersas nas suspensões experimentais por 5 minutos, e cobertas pelas pastas testadas. Em intervalos de 24, 48 e 72 horas, as pontas de papel foram imersas em 10 ml de Letheen Broth, seguido de incubação a 37°°C por 48 horas. O crescimento microbiano foi avaliado pela turvação do meio de cultura. Um inóculo de 0.1 ml obtido do Letheen Broth foi transferido para 7 ml de BHI, e incubado a 37°°C por 48h. o crescimento bacteriano foi novamente avaliado pela turvação do meio de cultura. As pastas contendo hidróxido de cálcio e solução salina, hidróxido de cálcio-iodofórmio e solução salina mostraram significativa atividade antimicrobiana nos métodos experimentais estudados. A pasta contendo iodofórmio e solução salina foi inefetiva pelo teste de difusão em agar e, também, por exposição direta, para o B. subtilis e a mistura

Working Length Determination Using Cone-Beam Computed Tomography, Periapical Radiography and Electronic Apex Locator in Teeth with Apical Periodontitis: A Clinical Study

Introduction: The purpose of this clinical study was to compare the accuracy of working length (WL) determination using cone-beam computed tomography (CBCT), conventional periapical radiographies and electronic apex locator. Methods and Materials: This study was conducted during root canal treatment of 19 patients with a total of 30 single-rooted teeth diagnosed with apical periodontitis. After taking the initial parallel periapical radiographies, the initial file was advanced into the canal until the WL was detected by the apex locator. Subsequently, the WL was measured and WL radiographies were taken with the file set in the canal. Afterwards, CBCT images were acquired. These three measurements were tabulated and compared and the data were analyzed using the Friedman test. The level of significance was set at 0.05. Results: The mean values for WL determination by electronic apex locator, periapical radiograph and CBCT images were 22.25, 22.43 and 22.65, respectively which was not statistically significant (P>0.05). Conclusion: Working length determination using CBCT images was precise when compared to radiographic method and electronic apex locator.Keywords: Apical Foramen; Cone-Beam Computed Tomography; Dental Radiography; Electronic Apex Locator; Tooth Ape

Effect of dental bleaching on pulp oxygen saturation in maxillary central incisors - a randomized clinical trial

Objective: To assess pulp oxygen saturation levels (SaO2) in maxillary central incisors after dental bleaching. Materials and Methods: 80 participants (160 teeth) were randomly allocated to four groups: G1 In-office bleaching with two applications of 35% hydrogen peroxide (HP) (20 minutes), followed by at-home bleaching with 10% carbamide peroxide (CP) (2 hours/day for 16 days); G2 - Same protocol as G1, plus desensitizing toothpaste; G3 - Inoffice bleaching with 35% HP and one application of placebo gel (20 minutes), followed by at-home bleaching with 10% CP (2 hours/day for 16 days); and G4 - Same protocol as G3, plus desensitizing toothpaste. Pulp SaO2 levels were measured before (T0) and immediately after (T1) in-office bleaching; on the 5th (T2), 8th (T3), 12th (T4), and 16th days of at-home bleaching (T5); and on the 7th (T6) and 30th (T7) days. Mean (SD) pulp SaO2 levels were compared within groups by generalized estimating equations (GEE) and Student’s t-test (P<0.05). Results: Mean pulp SaO2 at T0 was 84.29% in G1, 84.38% in G2, 84.79% in G3, and 85.83% in G4. At T1, these values decreased to 81.96%, 82.06%, 82.19%, and 81.15% in G1, G2, G3, and G4 respectively, with significant difference in G4 (P<0.05). During home bleaching, pulp SaO2 levels varied in all groups, with 86.55%, 86.60%, 85.71%, and 87.15% means at T7 for G1, G2, G3, and G4, respectively; G2 presented significant difference (P<0.05). Conclusions: Pulp SaO2 level in maxillary central incisors was similar at baseline, reducing immediately after in-office bleaching, regardless of using desensitizing toothpaste and increasing at 30 days after dental bleaching

Expression of CD90 and P75NTR stem cell markers in ameloblastomas : a possible role in their biological behavior

Multicystic and unicystic ameloblastomas are benign odontogenic tumors that present distinct biological behavior. The investigation of stem cells has become an important branch of tumor biology, with several studies addressing the possible role of these cells in tumor growth, angiogenesis, progression, infiltration and invasiveness. This study evaluated the immunohistochemical expression of CD90(Thy-1) and P75NTR stem cell markers in multicystic and unicystic ameloblastomas. Seventeen (17) samples of ameloblastomas (multicystic, n = 10; unicystic, n = 7) were submitted to immunohistochemical reactions and graded semi-quantitatively. The Kolmogorov-Smirnov test was used to verify possible differences in CD90 and P75NTR expressions between multicystic and unicystic ameloblastomas (p < 0.05). CD90 immunostaining was observed in all multicystic ameloblastoma specimens (n = 10), in the cytoplasm of the fibroblasts and vascular endothelial cells of the tumor stroma, near the neoplastic odontogenic epithelia. The staining of stromal CD90 was significantly higher in multicystic than in unicystic ameloblastomas (p = 0.003). Nuclear P75NTR immunostaining was observed in all ameloblastoma specimens. A significant difference was seen in the epithelial staining of P75NTR between multicystic and unicystic types (p = 0.007). The increased expression of CD90 and P75NTR found in multicystic ameloblastomas suggests a behavioral biological difference between multicystic and unicystic ameloblastomas, as well as a difference in ameloblastoma development

Estudos longitudinais da influência do veículo na eficácia da pasta de hidróxido de cálcio em infecções endodônticas: revisão sistemática

Longitudinal studies about the influence of the vehicle on the efficacy of calcium hydroxide pastes in endodontic infections were studied through a systematic review. Bibliographic tabulation sources identified electronically by MEDLINE, since 1966 until January 2nd of 2007 and Cochrane Library, on the same period, were used. As searching strategy the following terms were used in different combinations: calcium hydroxide, chlorexidine, root canal infection, faecalis, intracanal dressing, endodontic infection, intracanal medicament, paramonochlorophenol, paramonochlorophenol or p-monochlorophenol. The studies were selected by two independent reviewers that also determined the inclusion and exclusion criteria. The search presented 303 related articles, and from these, 22 articles were literature reviews, 71 articles were related to in vivo studies (humans or animals), 34 studies were cases reports, and 178 included in vitro studies. From the 71 in vivo studies, 5 studies satisfied the inclusion criteria, what enabled the data analysis. The impossibility of results combination caused by the methodology differences of the studies did not allow the execution of meta-analysis. In vitro studies showed that the vehicle influences the chemical characteristics of the calcium hydroxide paste on what concerns to the speed of diffusion an ionic dissociation, like occurs with aqueous Hydro-solvable vehicles. This chemical characteristic reflects on the antimicrobial potential. On the five studies in humans that satisfied the inclusion criteria for analysis of scientific evidence, from a total of 110 teeth with endodontic infections, after the sanitization process combined with the calcium hydroxide paste associated to saline solution, in 35 teeth were detected microorganisms on the final samples. The saline solution was the only vehicle present in all the included studies, what limited comparisons. Considering the estimative of clinical success, the adequate sanitization process assisted by the calcium hydroxide paste with aqueous vehicle reduces the endodontic microorganisms, what favors the prognostic.Mestre em OdontologiaAvaliou-se em estudos longitudinais a influência do veículo na eficácia de pastas de hidróxido de cálcio em infecções endodônticas, por meio de revisão sistemática. Empregaram-se fontes de catalogação bibliográfica identificadas eletronicamente por MEDLINE, a partir de 1966 até 02 de janeiro de 2007 e Cochrane Library. Como estratégia de busca utilizou-se os termos calcium hydroxide, chlorhexidine, root canal infection, faecalis, intracanal dressing, endodontic infection, intracanal medicament, paramonochlorophenol, para monochlorophenol ou p-monochlorophenol em diferentes combinações. Os estudos foram selecionados por dois revisores, independentes, que também determinaram os critérios de inclusão e exclusão. A busca apresentou 303 artigos, sendo que destes, 22 artigos eram de revisão de literatura, 71 artigos relacionavam-se com estudos in vivo (humanos ou animais), 34 estudos eram relatos de casos clínicos e 178 incluíam estudos in vitro. Dos 71 estudos in vivo, 5 estudos satisfizeram os critérios de inclusão, o que possibilitou a análise dos dados. A impossibilidade da combinação de resultados causada pelas diferenças nos métodos dos estudos não favoreceu o desenvolvimento da meta-análise. Verificou-se que o veículo influencia nas características químicas da pasta de hidróxido de cálcio no que concerne à velocidade de difusão e dissociação iônica, como ocorre com os veículos hidrossolúveis aquosos. Esta característica química reflete no potencial antimicrobiano. Nos cinco estudos em humanos que satisfizeram os critérios de inclusão para análise de evidência científica, do total de 110 dentes com infecções endodônticas, após o processo de sanificação coadjuvado pela pasta de hidróxido de cálcio associada à solução fisiológica, em 35 dentes foi detectado microrganismos nas amostras finais. A solução fisiológica foi o único veículo presente em todos os estudos incluídos, o que restringiu comparações. Considerando a estimativa de êxito clínico, o adequado processo de sanificação auxiliado pela pasta de hidróxido de cálcio com veículo aquoso reduz a microbiota endodôntica, o que favorece o prognóstico