Publications by authors named "José Antonio Poli de Figueiredo"

67 Publications

Use of autofluorescence and fluorescent probes as a potential diagnostic tool for oral cancer: A systematic review.

Photodiagnosis Photodyn Ther 2021 Mar 21;33:102073. Epub 2020 Nov 21.

Department of Morphological Sciences, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil. Electronic address:

Introduction: The prognosis of patients with Oral squamous cell carcinoma (OSCC) are directly related to the stage of development of the tumor at the time of diagnosis, but it is estimated an average delay in diagnosis of 2-5 months. New non-invasive techniques for the early diagnosis of OSCC are being developed, such as methodologies to detect spectral changes of tumor cells. We conducted a systematic review to analyze the potential use of autofluorescence and/or fluorescent probes for OSCC diagnosis.

Material And Methods: Four databases (PubMed, Scopus, Embase and Web of Science) were used as research sources. Protocol was registered with PROSPERO. It was included studies that evaluated tissue autofluorescence and/or used fluorescent probes as a method of diagnosing and/or treatment of oral cancer in humans.

Results: Forty-five studies were selected for this systematic review, of which 28 dealt only with autofluorescence, 18 on fluorescent probes and 1 evaluated both methods. The VELscope® was the most used device for autofluorescence, exhibiting sensitivity (33%-100%) and specificity (12%-88.6%). 5-Aminolevulinic acid (5-ALA) was the most used fluorescent probe, exhibiting high sensitivity (90%-100%) and specificity (51.3%-96%). Hypericin, rhodamine 6 G, rhodamine 610, porphyrin and γ-glutamyl hydroxymethyl rhodamine green have also been reported.

Conclusion: Thus, the autofluorescence and fluorescent probes can provide an accurate diagnosis of oral cancer, assisting the dentist during daily clinical activity, but it is not yet possible to suggest that this method may replace histopathological examination.
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http://dx.doi.org/10.1016/j.pdpdt.2020.102073DOI Listing
March 2021

Antimicrobial effect of photodynamic therapy on intracanal biofilm: A systematic review of in vitro studies.

Photodiagnosis Photodyn Ther 2020 Dec 25;32:102025. Epub 2020 Sep 25.

Brazilian Lutheran University, ULBRA, Dental School, Av. Farroupila, 8001 Bairro São José, Canoas, RS, CEP 92425-020, Brazil.

Background: Antimicrobial photodynamic therapy (A-PDT), is one of the adjunctive therapies developed to improve the effectiveness of root canal disinfection.. The aim of this study was to analyze the antimicrobial effect of PDT on intracanal biofilm.

Methods: Two reviewers conducted a literature search in PubMed, MEDLINE, Lilacs, SciELO, EMBASE and Google Scholar using the following search strategy: photochemotherapy "[Mesh] OR (photodynamic therapy) AND" dental plaque "[Mesh] OR (dental biofilm) AND (root canal). The following data were collected: publication year, author's name, study site, type of study, participant number, type of photosensitizer, type of laser, method of data collection, application time and results. Study quality was assessed using the Methodological Index for Non-Randomized Studies (MINORS).

Results: After selection based on title, abstract and full text, 27 studies were included in this systematic review. PDT reduced bacterial viability in most studies when combined with conventional endodontic techniques.

Conclusion: PDT reduced bacterial counts in most studies, especially when used as an adjunct to the conventional endodontic technique to treat refractory infection. However, PDT effects on in vitro bacterial biofilm were not accurately quantified because of the numerous biases in the studies reviewed.
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http://dx.doi.org/10.1016/j.pdpdt.2020.102025DOI Listing
December 2020

The COVID-19 Pandemic and Planetary Health. A Critical Review of Epidemiology, Prevention, Clinical Characteristics and Treatments for Oral, Head and Neck Health Professionals. Do We Have a Roadmap?

Int Arch Otorhinolaryngol 2020 Jul 31;24(3):e351-e358. Epub 2020 Jul 31.

School of Public Health, Columbia University, Columbia, NY, United States of America.

 Coronavirus disease 19 (COVID-19) is potentially the greatest global public health crisis of this century. This disease emerged as an outbreak of pneumonia of unknown cause in Wuhan, the capital city of the Hubei province in China, in December 2019. Otolaryngologists, head and neck surgeons and dentists are at an increased risk of occupational disease.  The present review summarizes currently published evidence of Covid-19 epidemiology, clinical characteristics, treatment and prevention. No proven effective treatments for this disease currently exist.  COVID-19 started from a zoonotic transmission event associated with a large seafood market that also traded in live wild animals, and it soon became clear that efficient person-to-person transmission was also occurring. Symptoms are varied, and not all patients develop all of them.  Social distancing seems to have been successful in several places in the world. However, this recommendation alone is not enough to contain the disease, and it is not a long-term solution. Large-scale testing by health professionals of representative samples of the population may give an estimate of the progression of the disease. Different treatments are under test and bring hope of a cure to the population. However, no current treatments (April 27, 2020) have been proven to be the key to success in the treatment of patients with COVID-19. Planetary health is a useful concept to understand the current drivers of this pandemic and to draw a roadmap for science and healthcare that may guide actions to fight economic depression and ensure a healthy recovery.
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http://dx.doi.org/10.1055/s-0040-1714143DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7394647PMC
July 2020

Association of calcium hypochlorite, reciprocating instrumentation and photodynamic therapy: Antimicrobial analysis and effects on root dentin structure.

Photodiagnosis Photodyn Ther 2020 Mar 19;29:101625. Epub 2019 Dec 19.

School of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.

Introduction: This study aimed to evaluate the antimicrobial action of calcium hypochlorite(Ca[OCl]) and sodium hypochlorite (NaOCl) with reciprocating instrumentation and photodynamic therapy(PDT), and its influence on root dentin structure.

Methods: One hundred and ten human teeth were used to antimicrobial evaluation, inoculated with Enterococcus faecalis and divided into 11 groups (n = 10): G1 - distilled water(control); G2-1 % NaOCl; G3-5.25 % NaOCl; G4-1 % Ca(OCl); G5-5.25 % Ca(OCl); G6-PDT; G7-distilled water + PDT; G8-1 % NaOCl + PDT; G9-5.25 % NaOCl + PDT; G10-1 % Ca(OCl)+PDT; G11-5.25 % Ca(OCl)+PDT. In all groups, except G6, the root canals were instrumented with #R50 Reciproc file in the working length in association with tested chemical auxiliary substance. The counting of colony forming units (CFUs) was performed to calculate the bacterial percentage reduction of each group. Following, 55 bovine teeth were used to microhardness evaluation and divided into the same 11 groups (n = 5), with no instrumentation and immersion in the tested protocols. The modification of root dentin microhardness was evaluated by using the Vicker tester. Finally, 33 bovine teeth were used to organic components evaluation and divided into the same 11 groups (n = 3), with no instrumentation and immersion in the tested protocols. The modification of organic components of root dentin was evaluated by light microscopy. Specific statistical analysis was performed for each evaluation.

Results: The higher bacterial reduction was observed in groups 3,4,5,8,9,10 and 11, with no statistical difference between them (p > 0.05). The higher microhardness reduction was observed in groups 8,9,10 e 11, with no statistical difference between them (p > 0.05). The highest modification on organic components was observed in groups 3,5,9 and 11, with no statistical difference between them (p > 0.05).

Conclusions: The association of Ca(OCl), reciprocating instrumentation and PDT promotes effective antimicrobial action. Moreover, lower modification was induced in microhardness and organic components of root dentin, by using Ca(OCl) in low concentration associated to PDT.
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http://dx.doi.org/10.1016/j.pdpdt.2019.101625DOI Listing
March 2020

Periradicular inflammatory response, bone resorption, and cementum repair after sealing of furcation perforation with mineral trioxide aggregate (MTA Angelus™) or Biodentine™.

Clin Oral Investig 2019 Nov 12;23(11):4019-4027. Epub 2019 Mar 12.

Department of Oral Biology, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.

Objective: This study assessed tissue responses after furcation perforation and immediate sealing with either Biodentine™ or MTA Angelus™.

Material And Methods: Sixty male Wistar rats were used (n = 6 per group/period). The mandibular first molars had the furcation mechanically exposed and sealed with either MTA or Biodentine™ and restored with silver amalgam. In an additional test group, teeth were sealed only with Biodentine™. Furcation sealing with gutta-percha and silver amalgam restoration served as positive control, and healthy untreated teeth were the negative control. Histological evaluation was performed after 14 or 21 days. Kruskal-Wallis and Dunn's post hoc tests were performed to analyze the extent and intensity of tissue inflammation, bone resorption, and cementum repair (p < 0.05).

Results: Biodentine™ and MTA presented satisfactory results, showing a milder inflammatory response when compared to the control, regardless of the material used for coronal sealing and of the experimental period evaluated (p < 0.0001). All test groups showed less bone resorption than the positive control after 21 days (p < 0.05), and such differences were more pronounced in teeth restored with silver amalgam. Cementum repair was performed in 30% of MTA and Biodentine™ samples but not carried out in any positive control specimen.

Conclusions: Biodentine™ and MTA promoted similar responses when used to seal furcation perforations and should therefore be regarded as a promising alternative.

Clinical Relevance: Knowledge about tissue responses to restorative materials is essential for improving root perforation sealing protocols. The present results showed that both Biodentine™ and MTA promoted appropriate periradicular tissue reactions in a preclinical test for evaluating furcation perforation treatments.
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http://dx.doi.org/10.1007/s00784-019-02833-zDOI Listing
November 2019

Correction to: Influence of foraminal enlargement on the healing of periapical lesions in rat molars.

Clin Oral Investig 2019 04;23(4):2001-2003

Department of Endodontics, Bahia School of Medicine and Public Health, Avenida Dom João VI, 275, Salvador, BA, 40290-000, Brazil.

Figures 2 and 3 in the published version of this article contained a mistake. CCP and DCP should have been FEG and NFEG. Correct figures are presented here.
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http://dx.doi.org/10.1007/s00784-018-2780-8DOI Listing
April 2019

Bacteriophages in Dentistry-State of the Art and Perspectives.

Dent J (Basel) 2019 Jan 9;7(1). Epub 2019 Jan 9.

Department of Morphological Sciences, Federal University of Rio Grande do Sul-UFRGS, Porto Alegre 90040-060, Brazil.

Bacteriophages, viruses capable of killing bacteria, were discovered in 1915, but the interest in their study has been limited since the advent of antibiotics. Their use in dentistry is still very limited. The authors reviewed studies about bacteriophage structure, mode of action, uses in oral health, and possible future uses in dentistry associated with their possible action over biofilm, as well as the advantages and limitations of phage therapy.
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http://dx.doi.org/10.3390/dj7010006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6473837PMC
January 2019

Influence of foraminal enlargement on the healing of periapical lesions in rat molars.

Clin Oral Investig 2019 Apr 1;23(4):1985-1991. Epub 2018 Nov 1.

Department of Endodontics, Bahia School of Medicine and Public Health, Avenida Dom João VI, 275, Salvador, BA, 40290-000, Brazil.

Objectives: The aim of this study was to evaluate the influence of foraminal enlargement on the healing of induced apical periodontitis in a rat model.

Material And Methods: Periapical lesions were bilaterally induced in mandibular first molars of 24 Wistar rats, through root canals exposure to the oral environment during 3 weeks. Endodontic treatment was performed in the mesial canal of right molars, which were separated into two experimental groups (n = 12/group). The foraminal enlargement group (FEG) received instrumentation in the entire root canal length, including the cemental canal, while in the non-foraminal enlargement group (NFEG), instrumentation was carried out 1 mm short of the apical foramen. Root canals were filled with gutta-percha and AH Plus sealer, in the same visit, 1 mm short of the apical foramen in both experimental groups. Left molars were not treated and served as a baseline control group. The animals were killed after 4 weeks, and their hemi-mandibles were prepared for radiographic and histological analysis. Data were analyzed by Student's t test and ANOVA.

Results: Only FEG presented lower areas of periapical radiolucency compared to the control (p < .05). Both FEG and NFEG allowed decreased inflammation intensity (p < .0001 and p < .01) and higher scores of cementum neoformation when compared to non-treated samples (p < .0001). FEG was more effective than NFEG in promoting biological seal, i.e., apical closure with cementum (p < .01). FEG, but not NFEG, showed lower scores of root resorption than the control.

Conclusions: Foraminal enlargement during root canal preparation improved periapical healing in rat molars.

Clinical Significance: Foraminal enlargement has been suggested to improve disinfection at the apical portion of root canals. This procedure may favor the healing of chronic periapical lesions.
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http://dx.doi.org/10.1007/s00784-018-2628-2DOI Listing
April 2019

Dendritic cells and their relation to apical peridontitis.

Braz Oral Res 2018 Oct 18;32(suppl 1):e71. Epub 2018 Oct 18.

Pontifícia Universidade Católica do Rio Grande do Sul - PUCRS, School of Dentistry, Clinical Department, Porto Alegre, RS, Brazil.

The purpose of this manuscript was to re-discuss apical periodontitis, apical biofilm, and its possible relationship with dendritic cells (DC). DCs are potent regulators of the immune system and their function is divided into three categories that involve the presentation of antigens: the presentation of antigens and activation of T cells; a not well established category suggested that DCs induce and maintain immunological tolerance; and the maintenance of the immune memory in conjunction with B cells. DCs in periapical inflammatory lesions are composed of at least two subpopulations that can be distinguished on the basis of ultrastructure and phenotype. These populations might differ in lineage, state of maturation, differentiation, activation, and/or function. The authors hereby analyzed the root apexes of teeth under SEM, after performing apicoectomy due to the failure of conventional endodontic treatment. Microbial biofilm with multispecies and areas of resorption with the presence of Howship lacunae, and images suggestive of denditric cells could be observed. The presence of DCs in periapical lesion could be an indication of the severity of the lesion, with a constant presence of antigen in the periradicular region.
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http://dx.doi.org/10.1590/1807-3107BOR-2018.vol32.0071DOI Listing
October 2018

Dentists' knowledge of dental trauma based on the International Association of Dental Traumatology guidelines: A survey in South Brazil.

Dent Traumatol 2019 Feb 20;35(1):27-32. Epub 2018 Nov 20.

Dental School, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.

Background/aim: Dental trauma is a public health issue with a high prevalence in children. The aim of this study was to evaluate the level of knowledge of dentists in Rio Grande do Sul, Brazil, of the management of traumatic dental injuries, using the International Association of Dental Traumatology (IADT) Guidelines as a reference.

Materials And Methods: An electronic questionnaire investigating personal and professional characteristics and 12 questions about dento-alveolar trauma, was sent to all registered dentists of the Regional Council of Dentistry of Rio Grande do Sul (n=14 753). The respondents were grouped according to the sociodemographic and professional profiles and the data were evaluated by the Student-T test or one-way ANOVA, with Tukey's post-hoc, with α = 5%.

Results: A total of 1414 dentists responded to the survey (9.59% response rate). The overall mean self-reported knowledge of dental trauma was 5.87 ± 1.57, of a maximum possible score of 12. Some factors associated with a higher knowledge of the IADT guidelines were: female gender, previous clinical experience, years from qualification, self-reported knowledge, and academic postgraduate degree. Dentists who are specialized in endodontics (6.58 ± 1.63) and pediatric dentistry (6.05 ± 1.44) achieved higher levels of knowledge on dental trauma. Analysis of the characteristics (gender, location, and proportion of specialists) of the respondents confirmed that they were representative of the target population.

Conclusion: The overall level of knowledge of dentists from Rio Grande do Sul of the IADT guidelines is moderate. These results highlight the need for continuing education on dento-alveolar trauma in this population.
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http://dx.doi.org/10.1111/edt.12450DOI Listing
February 2019

Antimicrobial efficacy of 0.5% peracetic acid and EDTA with passive ultrasonic or manual agitation in an Enterococcus faecalis biofilm model.

Aust Endod J 2019 Apr 13;45(1):57-63. Epub 2018 Aug 13.

Adelaide Dental School, The University of Adelaide, Adelaide, South Australia, Australia.

We compared the antimicrobial efficacy of EDTA and 0.5% peracetic acid (PAA), with manual agitation (MA) or passive ultrasonic irrigation (PUI) in an Enterococcus faecalis biofilm model. Fifty-five single-rooted human premolar teeth were chemo-mechanically prepared and inoculated with E. faecalis for biofilm formation. These were divided into five groups (n = 11): saline solution, PAA+MA, PAA+PUI, EDTA+MA and EDTA+PUI. Root canal sampling and scanning electron microscopy of the canal lumen and dentinal tubule areas at the different root thirds were performed. The images were ranked based on contamination level. Only the PAA groups presented with no bacterial growth, with the remaining groups not presenting significant differences among them. PAA+PUI presented with the highest median position rankings in every third and location, whereas EDTA+MA performed similarly to the saline control. No differences were found when comparing MA and PUI within the same solution, however, PUI was associated with lower contamination levels mean rankings.
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http://dx.doi.org/10.1111/aej.12279DOI Listing
April 2019

Antimicrobial activity of hypochlorite solutions and reciprocating instrumentation associated with photodynamic therapy on root canals infected with Enterococcus faecalis - An in vitro study.

Photodiagnosis Photodyn Ther 2018 Sep 24;23:347-352. Epub 2018 Jul 24.

School of Dentistry, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil.

Introduction: The aim of this study is to evaluate the antimicrobial activity of hypochlorite solutions and reciprocating instrumentation associated with photodynamic therapy (PDT).

Methods: One hundred and thirty two root canals were enlarged up to #35 K-file and inoculated with E.faecalis for 14 days. The 132 samples were randomly divided into eleven groups (n = 12) and subjected to the following protocols: G1-distilled water + Reciproc R40 (control), G2-1% sodium hypochlorite (NaOCl) + Reciproc R40, G3-2.5% NaOCl + Reciproc R40; G4-1% calcium hypochlorite (Ca[OCl]) + Reciproc R40, G5-2.5% Ca(OCl) + Reciproc R40; G6-PDT; G7-distilled water + Reciproc R40 + PDT, G8-1% NaOCl + Reciproc R40 + PDT, G9-2.5% NaOCl + Reciproc R40 + PDT; G10-1% Ca(OCl) + Reciproc R40 + PDT, G11-2.5% Ca(OCl) + Reciproc R40 + PDT. The percentage bacterial reduction was checked by counting the colony-forming units (CFUs) in 10 samples of each group. The remaining 2 samples of each group were submitted to scanning electronic microscopy (SEM) to illustrate the effectiveness of the proposed treatments. Data were subjected to one-way ANOVA followed by Tukey's post hoc test (α = 0.05).

Results: The greatest ability to promote bacterial reduction was observed in groups 8 (1% NaOCl + R40 + PDT), 9 (2.5% NaOCl + R40 + PDT), 10 (1% Ca[OCl] + R40 + PDT), and 11 (2.5% Ca[OCl] + R40 + PDT), with no significant difference between them (p < 0.05).

Conclusions: The association of PDT with hypochlorite solutions and reciprocating instrumentation provides effective elimination of E.faecalis.
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http://dx.doi.org/10.1016/j.pdpdt.2018.07.015DOI Listing
September 2018

Effectiveness of photodynamic therapy associated with irrigants over two biofilm models.

Photodiagnosis Photodyn Ther 2017 Dec 13;20:169-174. Epub 2017 Oct 13.

Department of Conservative Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.

Background: This study aimed to evaluate the antibacterial effect and the biofilm disruption promoted by antimicrobial photodynamic therapy (aPDT) associated with sodium hypochlorite (NaOCl) and chlorexidine (CHX) over monospecies and multispecies biofilms.

Methods: In monospecies model, forty-six premolars were inoculated with Enterococcus faecalis for 21days and divided into three groups: saline, CHX and NaOCl. After irrigation, aPDT was performed. Samples were collected at baseline (S1) and after irrigation (S2) and aPDT (S3). Colony-forming unit (CFU) counts were performed. In multispecies model, sixty bovine dentin blocks were infected intraorally for 72h and divided into six groups: saline, saline/aPDT, CHX, CHX/aPDT, NaOCl and NaOCl/aPDT. The percentage and the biovolume of live cells and the total biovolume were assessed using confocal laser scanning microscopy.

Results: CHX and NaOCl showed the lowest CFU counts (P<0.05). aPDT reduced the bacterial counts in saline (S2-S3; P<0.05). The lowest amount of live cells was observed in CHX, CHX/aPDT, NaOCl and NaOCl/aPDT. aPDT did not reduce the total biovolume (P>0.05).

Conclusion: aPDT associated with saline reduced the bacterial load in root canals infected with E. faecalis. aPDT did not reduce the total biovolume in situ; however, the irrigant was decisive to disrupt multispecies biofilms.
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http://dx.doi.org/10.1016/j.pdpdt.2017.10.003DOI Listing
December 2017

Histopathological, Microbiological, and Radiographic Analysis of Antimicrobial Photodynamic Therapy for the Treatment of Teeth with Apical Periodontitis: A Study in Rats' Molars.

Photomed Laser Surg 2017 Jul 9;35(7):364-371. Epub 2017 Mar 9.

1 Postgraduate Program in Dentistry, Pontifical Catholic University of Rio Grande do Sul (PUCRS) , Porto Alegre, RS, Brazil .

Objective: The aim of this study was to evaluate in vivo, by histological and radiographic analysis, the response of apical tissues of rats' teeth with experimentally induced apical periodontitis, after one- and two-session endodontic treatment with and without photodynamic therapy (PDT). A microbiological analysis was also performed to verify bacterial reduction after each treatment.

Background Data: Studies carried out in recent years highlighted the antibacterial potential of PDT when associated with conventional endodontic therapy in vitro. Although the antimicrobial effect of PDT is well-established, tissue response to PDT in teeth with apical periodontitis lacks studies.

Methods: Thirty-two rats' root canals were assigned to four groups: one session/PDT-[chemomechanical preparation (CMP)+root canal filling (RCF)]; two sessions/PDT- [CMP+calcium hydroxide (CH) for 14 days+RCF]; one session/PDT+ [CMP+PDT+RCF], and two sessions/PDT+ [CMP+PDT+CH for 14 days+RCF]. For microbiological evaluation, samples were collected before and after proposed treatments. For radiographic and histological analysis, the animals were euthanized after 28 days and the mandibles surgically removed.

Results: PDT associated with conventional endodontic therapy was able to promote significant bacterial reduction in root canals with induced apical periodontitis, but this reduction was not significantly different to conventional endodontic therapy alone. Although radiographic evaluation showed no significant differences, histological analysis showed lower scores for neutrophils/eosinophils in PDT-treated groups and macrophages/giant cells in CH groups.

Conclusions: The use of low-level laser as light source did not promote major improvement on radiographic and histological repair, but since the number of inflammatory cells slightly decreased, it may optimize repair by modulating inflammatory process. PDT may be indicated as an adjunct to conventional endodontic therapy for teeth with apical periodontitis, in association with an interappointment dressing with CH, in an attempt to produce better conditions to stimulate repair.
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http://dx.doi.org/10.1089/pho.2016.4102DOI Listing
July 2017

Influence of ultrasonic activation over final irrigants in the removal of photosensitizer from root canal walls after photodynamic therapy.

Photodiagnosis Photodyn Ther 2017 Mar 5;17:216-220. Epub 2017 Jan 5.

School of Dentistry, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil.

Introduction: The aim of the present study was to evaluate the influence of ultrasonic activation (US) of the final irrigant in the removal of the photosensitizer from root canal walls after photodynamic therapy.

Methods: The root canals of 60 single-rooted bovine extracted teeth were filled with 0.01% methylene blue and submitted to photodynamic therapy for 90s. After that, the roots were divided into six groups (n=10) according to the final irrigation protocol: distilled water (DW), DW+US, 17% EDTA, QMix, EDTA+US, and QMix+US. Then, the samples were submitted to scanning electron microscopy where a scoring system was used to evaluate the images and effectiveness of proposed treatments in the cervical, middle and apical regions of the root canals. The data were statistically analyzed by the Kruskal-Wallis and Mann-Whitney U tests for intergroup comparisons as well as the Wilcoxon and Friedman tests for intragroup comparisons at 5% of significance.

Results: The 17% EDTA+US and QMix+US treatments were most effective in the removal of the photosensitizer in all regions of the root canal; the difference was statistically significant when compared to all other groups (p<0.05). There were no significant differences in the intragroup analysis comparing the effectiveness in the different regions of the same group (p<0.05).

Conclusions: US can aid 17% EDTA and QMix in removing the photosensitizer after photodynamic therapy and contributes to cleaning root canal walls.
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http://dx.doi.org/10.1016/j.pdpdt.2016.12.011DOI Listing
March 2017

Biological Tissue Response to a New Formulation of a Silicone Based Endodontic Sealer.

Braz Dent J 2016 Oct-Dec;27(6):657-663

Department of Conservative Dentistry, Dental School, UFRS - Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.

Satisfactory biological behavior is a necessary requirement for clinical application of endodontic materials. In this study, the connective tissue responses to silicone (GuttaFlow 2), epoxy resin (AH Plus) and zinc oxide and eugenol (Endofill) based sealers were compared. Twelve Wistar rats had polyethylene tubes (four per animal) containing one of the tested sealers and empty tubes (negative control) implanted in their subcutaneous tissue. The tubes were randomly placed 2 cm from the spine and at least 2 cm apart from one another. Tissue samples with implants were processed for histological analysis after 7 or 60 days (n=6 animals per period). Inflammatory cells, fibrous condensation and abscess were scored according to their intensity. Friedman, followed by Dunn's post hoc, was used to compare sealers. Differences between the two experimental periods were verified using Mann-Witney U test (p<0.05). At 7 days, most of the histological parameters showed no significant differences amongst groups. Endofill group scored higher than the others for giant cells (o<0.05) and promoted a greater number of samples presenting abscess formation. GuttaFlow 2 tended to show a less intense inflammatory infiltrate compared to the other materials. At 60 days, there were no significant differences between groups in most of the histological parameters evaluated. However, it was observed that Endofill scored higher for macrophages (p<0.05) compared to the control group, and GuttaFlow 2 tended to present lower scores than the others for neutrophils and abscess. GuttaFlow 2 showed proper biological behavior and should be considered adequate for clinical practice.
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http://dx.doi.org/10.1590/0103-6440201600719DOI Listing
April 2017

Final irrigation protocols may affect intraradicular dentin ultrastructure.

Clin Oral Investig 2017 Sep 25;21(7):2173-2182. Epub 2016 Nov 25.

Department of Conservative Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.

Objectives: The aim of this study was to evaluate the effect of different irrigation protocols on the root dentin structure using scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Materials And Methods: Thirty-nine lower bovine incisors were hemisected longitudinally and randomly divided into 13 groups (n = 3). After the root halves were reassembled, it was applied a specific irrigation protocol for each group, as following: G1, distilled water (control); G2, 0.9% saline; G3, saline + 17% EDTA; G4, saline + PUI; G5, saline + PUI + EDTA; G6 to G9 received the same protocol as above replacing 0.9% saline by 2.5% NaOCl; and G10 to G13 by 2% CHX. One-half of each sample was prepared and evaluated using SEM and the other one by TEM observations.

Results: TEM descriptive analysis showed modifications in dentin organic ultrastructure, characterized by the thinning of dentin collagen fibrils, caused by NaOCl, enhanced by EDTA and/or PUI. SEM analysis showed that NaOCl with PUI caused significantly larger erosion of the peritubular dentin than in all the other groups (P < 0.05), followed by NaOCl + EDTA and NaOCl + EDTA + PUI.

Conclusions: NaOCl caused ultrastructural alterations in the dentin collagen, and enhanced by EDTA and/or PUI, promoted peritubular and intertubular erosion.

Clinical Relevance: The effect of irrigating solutions on dentin ultrastructure was still unclear. The acknowledgment about the kind of solution, concentrations, application time, and sequence of use was important to achieve the right sanitization without jeopardizing the dentin ultrastructure quality.
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http://dx.doi.org/10.1007/s00784-016-2006-xDOI Listing
September 2017

LPS levels in root canals after the use of ozone gas and high frequency electrical pulses.

Braz Oral Res 2016 15;30. Epub 2016 Mar 15.

Clinical Department, School of Dentistry, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil.

The present study aims to verify the effect of ozone gas (OZY® System) and high frequency electric pulse (Endox® System) systems on human root canals previously contaminated with Escherichia colilipopolysaccharide (LPS). Fifty single-rooted teeth had their dental crowns removed and root lengths standardized to 16 mm. The root canals were prepared up to #60 hand K-files and sterilized using gamma radiation with cobalt 60. The specimens were divided into the following five groups (n = 10) based on the disinfection protocol used: OZY® System, one 120-second-pulse (OZY 1p); OZY® System, four 24-second-pulses (OZY 4p); and Endox® System (ENDOX). Contaminated and non-contaminated canals were exposed only to apyrogenic water and used as positive (C+) and negative (C-) controls, respectively. LPS (O55:B55) was administered in all root canals except those belonging to group C-. After performing disinfection, LPS samples were collected from the canals using apyrogenic paper tips. Limulus Amoebocyte Lysate (LAL) was used to quantify the LPS levels, and the data obtained was analyzed using one-way ANOVA. The disinfection protocols used were unable to reduce the LPS levels significantly (p = 0.019). The use of ozone gas and high frequency electric pulses was not effective in eliminating LPS from the root canals.
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http://dx.doi.org/10.1590/1807-3107BOR-2016.vol30.0019DOI Listing
May 2016

Guided bone regeneration in osteoporotic conditions following treatment with zoledronic acid.

Clin Oral Implants Res 2017 Mar 26;28(3):362-371. Epub 2016 Feb 26.

Clinical Oral Research Centre, Institute of Dentistry, Bart's & The London School of Medicine & Dentistry, Queen Mary University, London, UK.

Objectives: To evaluate new bone formation in calvarial critical size defects (CSD) under dense polytetrafluoroethylene (d-PTFE), microporous membranes for guided bone regeneration (GBR) in healthy, osteoporotic and osteoporotic treated with zoledronic acid (ZA) rats.

Methods: Forty-eight, female, 6-month old Wistar rats were included in the study. Osteoporosis was induced by ovariectomy (OVX) and calcium-deficient diet in 32 rats. Sixteen OVX rats were treated with a single dose of Zolendronic Acid (ZA) (OZ), while 16 OVX rats received no treatment (O). The remaining 16 rats were sham-operated and used as healthy controls (C). At 6 weeks following osteoporosis induction, two 5 mm CSD were created in the parietal bones and one of them was treated with a double d-PTFE membrane. The healing periods were 30 and 60 days. New bone formation (NB) was assessed by qualitative and quantitative histological analysis.

Results: After 30 days of healing, NB (mean% (95% CI)) was 78.9% (21), 93.1% (9.3) and 84.2% (26.9) in the membrane treated defects and 18.8% (24.1), 27.1% (7.9) and 31% (38.8) in the untreated defects of group O, OZ and C, respectively. After 60 days of healing, NB was 78.3% (14.4), 95.8% (9) and 90.1% (26.1) in the membrane treated defects and 10.8% (17.4), 51.6% (39.4) and 15.7% (12.1) in the untreated defects of group O, OZ and C, respectively. Hierarchical analysis of variance showed that treatment with ZA (P = 0.001) and the use of membrane (P = 0.000) significantly increased new bone formation while presence of osteoporosis may have reduced new bone formation (P = 0.028).

Conclusion: d-PTFE membranes for GBR promote bone healing in osteoporotic and healthy rats. Treatment with ZA may improve new bone formation in osteoporotic rats.
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http://dx.doi.org/10.1111/clr.12810DOI Listing
March 2017

Bovine Pulp Tissue Dissolution Ability of Irrigants Associated or Not to Ultrasonic Agitation.

Braz Dent J 2015 Oct;26(5):537-40

Clinical Department, Dental School, PUCRS - Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil.

The aim of this study was to evaluate the tissue dissolution ability of different irrigating solutions associated or not to ultrasonic agitation. Ninety bovine pulp fragments (n=10 per group) were weighed and then placed individually in Eppendorf test tubes containing the following irrigants: G1- 2.5% sodium hypochlorite (NaOCl); G2- 2.5% NaOCl + ultrasonic agitation (US); G3- 2.5% NaOCl + 0.2% cetrimide (CTR); G4- 2.5% NaOCl + 0.2% CTR + US; G5- 400 ppm Sterilox (SX); G6- SX + US; G7- 0.2% CTR; G8- 0.2% CTR + US; G9- saline solution. Two blinded observers assessed the samples continuously for the first 4 h, and then every hour for the next 12 h. Dissolution speed was calculated by dividing the initial pulp weight (mg) by the period of time until complete dissolution (min). Data were compared by ANOVA and Tukey post hoc test with a 5% significance level. G1 to G4 dissolved pulp fragments completely and G2 was significantly faster than the other groups. G5 to G9 did not exhibit dissolving activity. In conclusion, only groups containing NaOCl were capable of pulp tissue dissolution, which was enhanced by ultrasonic agitation, but did not alter when 0.2% cetrimide was associated. This isolated solution and Sterilox showed no dissolving capacity, regardless the use of ultrasound.
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http://dx.doi.org/10.1590/0103-6440201300243DOI Listing
October 2015

Effect of different irrigating solutions and photo-activated therapy for in vivo root canal treatment.

Braz Dent J 2015 May-Jun;26(3):228-33

Post-Graduate Program in Dentistry, Dental School, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil.

This study aimed to evaluate histologically the effect of irrigation with 400 ppm Sterilox, 2% and 5% sodium hypochlorite (NaOCl), with and without photo-activated therapy (PAD), in a single-visit root canal treatment of dog's teeth with apical periodontitis (AP). Ten dogs were randomly divided into two groups (n=5): with and without PAD, and the root canals into four subgroups, according to the irrigating solution: SX (400 ppm Sterilox), SH2 (2% NaOCl), SH5 (5% NaOCl) and SS (saline solution) as positive control. A total of 134 root canals were opened and left exposed to the oral environment for 14 days and then sealed for 60 days for AP induction. Then, root canals were treated according to each proposed disinfecting protocol and filled in the same session. After 120 days, the dogs were euthanized and the periapical inflammatory events were evaluated under light microscopy. Qualitative data were submitted to Kruskal-Wallis and Mann-Whitney tests (α=0.05). PAD did not produce significant differences in the scores for apical inflammation when used after chemo-mechanical preparation (p>0.05). The irrigating solutions SX, SH2 and SH5 without PAD were statistically different from SS (p<0.05) that presented the greatest scores for apical inflammation. PAD did not show any additional effect for the treatment of root canals with pulp necrosis and AP in a single visit and 400 ppm Sterilox may be considered an alternative to NaOCl in root canal treatment.
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http://dx.doi.org/10.1590/0103-6440201300154DOI Listing
January 2017

Are bovine teeth a suitable substitute for human teeth in in vitro studies to assess endotoxin load in root canals?

Braz Oral Res 2015 3;29. Epub 2015 Jul 3.

Clinical Department, Dental School, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil.

The present study aimed to determine the feasibility of using bovine teeth as a suitable alternative for human teeth, in experiments involving in vitro endotoxin contamination. Twenty bovine central incisors and 20 human single-root premolars had their dental crowns removed and root lengths set at 16 mm. Root canals were prepared up to #60 K-file size and sterilized with cobalt-60 gamma irradiation (20 kGy, 6 h). The teeth were randomly divided into four groups: G1-bovine teeth (bovine negative control, n = 10), G2-human teeth (human negative control, n = 10), G3-bovine teeth, inoculated with Escherichia coli (055:B55) LPS, and G4-human teeth inoculated with E. coli LPS. The G1 and G2 groups were exposed to apyrogenic water. After the teeth had been incubated at 37 °C and atmospheric humidity for 24 h, the samples of solutions in the main canals were collected with apyrogenic absorbent paper tips. LPS levels were quantified using Limulus Amebocyte Lysate assay. The data obtained were statistically analyzed using one-way ANOVA, with a significance level of 5%. A high amount of endotoxin was detected in the inoculated human teeth (G4) when compared to the sterilized teeth (G2), as well as in the inoculated bovine teeth (G3) when compared to the inoculated human teeth (G4). However, there was no statistical difference between bovine teeth before and after the E. coli endotoxin inoculation. Therefore, under the mentioned experimental conditions, the use of bovine teeth should not be a choice for laboratory research on endotoxin contamination.
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http://dx.doi.org/10.1590/1807-3107BOR-2015.vol29.0087DOI Listing
November 2015

Permanent teeth pulpotomy survival analysis: retrospective follow-up.

J Dent 2015 Sep 3;43(9):1125-1131. Epub 2015 Jul 3.

Pontifical Catholic University of Rio Grande do Sul, Av. Ipiranga 6681, Prédio 6, sala 507, Porto Alegre, RS, Brazil, postal code: 90619-900. Electronic address:

Objectives: The aim of the present study is to evaluate risk factors influencing the success rates of pulpotomies both in young and adult populations.

Methods: Pulpotomies (n=273) performed by a single endodontic specialist were analyzed, and data on success rates were collected. Additionally, possible explanatory variables were noted such as: age, gender, clinical findings (teeth, type of restoration after pulpotomy), radiographic findings (dentin bridge formation) and systemic conditions. The follow-up period varied from 1 to 29 years, and the results were analyzed by Kaplan-Meier survival curves and also by Cox regression.

Results: Age at the time of pulpotomy ranged from 8 to 79 and had not influenced the success rates (p=0.35). The formation of dentin bridge had a strong protective effect (hazard ratio-HR=0.16, p<0.001). The prosthetic crown restorations following pulpotomy had the smallest failure rate, and amalgam has not increased the risk of failure significantly in relation to prosthesis. Resin composite restorations following pulpotomy increased in 263% the risk of failure (HR=3.63, p<0.001).

Conclusion: This study allowed inferences that pulpotomy may be a successful treatment at any age, and not only for young permanent teeth. It was also possible to conclude that the use of direct composite restorations following pulpotomies is associated with higher failure rates.
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http://dx.doi.org/10.1016/j.jdent.2015.06.010DOI Listing
September 2015

Effect of superoxidized water and sodium hypochlorite, associated or not with EDTA, on organic and inorganic components of bovine root dentin.

J Endod 2015 Jun 17;41(6):925-30. Epub 2015 Mar 17.

Department of Endodontics, School of Dentistry, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.

Introduction: This study aimed to evaluate the effects of Sterilox (Sx), a superoxidized water, 5% and 2% sodium hypochlorite (5NaOCl and 2NaOCl), and 17% EDTA (E) on the organic and inorganic components of bovine dentin.

Methods: Eighty bovine incisors were randomly divided into 8 groups (n = 10): 5NaOCl, 5NaOCl + E, 2NaOCl, 2NaOCl + E, Sx, Sx + E, E alone, and distilled water (H2O). Root canal instrumentation was performed by using the corresponding irrigant. The apical 15 mm was longitudinally sectioned into 2 fragments, one for light microscopy analysis in slides stained with picrosirius red (organic component) and the other for scanning electron microscopy analysis (inorganic component). Scores data obtained in the light microscopy analysis were submitted to the Kruskal-Wallis test, followed by multiple comparisons test (P < .05). Scanning electron microscopy images were analyzed descriptively.

Results: The chemical solution 5NaOCl had a greater effect on the organic component of dentin in area and depth than 2NaOCl. The chemical solutions 5NaOCl + E, 5NaOCl and 2NaOCl + E caused the greatest change in the collagenous organic matrix near the root canal lumen. The chemical solution 2NaOCl showed similar behavior to Sx, associated or not with E, promoting more superficial disorganization of collagen in a smaller area. Demineralization was observed in all groups in which E was used. However, areas of erosion and open dentinal tubules were detected only when it was combined with NaOCl.

Conclusions: Five percent NaOCl promoted the most extensive damage to the organic component of dentin, and when associated to EDTA, dentinal erosion could be seen. Considering these specific aspects, 2% NaOCl and Sx had milder effects on bovine root dentin.
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http://dx.doi.org/10.1016/j.joen.2015.01.039DOI Listing
June 2015

Photodynamic therapy in endodontics: a literature review.

Photomed Laser Surg 2015 Mar 26;33(3):175-82. Epub 2015 Feb 26.

1 Postgraduate Program in Dentistry, Pontifical Catholic University of Rio Grande do Sul , Porto Alegre, Rio Grande do Sul, Brazil .

Recently, several in vitro and in vivo studies demonstrated promising results about the use of photodynamic therapy during root canal system disinfection. However, there is no consensus on a standard protocol for its incorporation during root canal treatment. The purpose of this study was to summarize the results of research on photodynamic therapy in endodontics published in peer-reviewed journals. A review of pertinent literature was conducted using the PubMed database, and data obtained were categorized into sections in terms of relevant topics. Studies conducted in recent years highlighted the antimicrobial potential of photodynamic therapy in endodontics. However, most of these studies were not able to confirm a significant improvement in root canal disinfection for photodynamic therapy as a substitute for current disinfection methods. Its indication as an excellent adjunct to conventional endodontic therapy is well documented, however. Data suggest the need for protocol adjustments or new photosensitizer formulations to enhance photodynamic therapy predictability in endodontics.
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http://dx.doi.org/10.1089/pho.2014.3776DOI Listing
March 2015

Effect of super-oxidized water, sodium hypochlorite and EDTA on dentin microhardness.

Braz Dent J 2014 Sep-Oct;25(5):420-4

Department of Endodontics, School of Dentistry, PUCRS - Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.

The present study aimed to evaluate the influence of the following irrigating solutions on the microhardness of root canal dentin: 2% sodium hypochlorite (2NaOCl), 5% sodium hypochlorite (5NaOCl), super-oxidized water (400 ppm Sterilox - Sx) and 17% EDTA (E). Eighty roots from bovine incisors were randomly divided into 8 groups (n=10): 2NaOCl, 5NaOCl, Sx, and 2NaOCl + E, 5NaOCl + E, Sx + E (associated with E as final irrigant for 5 min), E solely and distilled water (dH2O) as the negative control. Root canal preparation was performed by hand instruments, using one of the irrigation protocols for 30 min. Then, 5 mm of the cervical root third were cut out from each sample and subjected to the Vickers microhardness test, at two points, one at approximately 500-1000 µm from the root canal lumen (distance 1), and the other at approximately 500-1000 µm from the external root surface (distance 2). Data were analyzed by Wilcoxon and Kruskal-Wallis tests at 5% significance level. Microhardness values at distance 1 were significantly lower than those at distance 2 for all groups, except 5NaOCl and 5NaOCl + E groups (p>0.05). EDTA showed the lowest microhardness values. However, no statistically significant difference was detected among groups at distance 1 and EDTA was significantly different only from Sx at distance 2. In conclusion, all tested solutions showed lower microhardness at the most superficial root canal dentin layer compared to the one found near the external root surface, except 5NaOCl and 5NaOCl + E; EDTA promoted lower microhardness values in comparison to Sterilox at this site.
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http://dx.doi.org/10.1590/0103-6440201300129DOI Listing
November 2016

Detection of apical inflammatory root resorption associated with periapical lesion using different methods.

Braz Dent J 2014 Sep-Oct;25(5):404-8

Department of Clinical Dentistry, PUCRS - Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil.

The aim of this study was to detect apical inflammatory root resorption (AIRR) associated with periapical lesion using cone beam computed tomography (CBCT) and scanning electronic microscopy (SEM). This clinical study evaluated AIRR in 88 root apexes, from 52 permanent teeth of 14 patients, extracted for different reasons. The patients were submitted to a clinical interview, review of dental/medical histories and clinical/imaging examinations for treatment planning. All selected teeth showed unrestorable condition because of the extensive coronal breakdown due to carious lesions, and root canal infection associated with periapical lesions. CBCT images were obtained from the patients with the aim of diagnosing the periapical diseases which showed complex or doubtful conditions. Two examiners assessed the presence or absence of AIRR. Apices were also analyzed under SEM. Chi-square test was used to compare the imaging methods for detection of AIRR. The level of statistical significance was set at 5%. AIRR associated with root canal infection and apical periodontitis was found in 61.4% of the cases studied by using SEM, and at least half of the cases by CBCT. The microscopic analysis remains as a reference standard against the imaging method to identify AIRR.
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http://dx.doi.org/10.1590/0103-6440201302432DOI Listing
November 2016

Accuracy of cone-beam computed tomography and periapical radiography in apical periodontitis diagnosis.

J Endod 2014 Dec 11;40(12):2057-60. Epub 2014 Oct 11.

Post-Graduate Program of Dentistry, School of Dentistry, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.

Introduction: This study aimed to investigate the correlation and the agreement between periapical radiography (PR) and cone-beam computed tomography (CBCT) correlating to histologic findings in the diagnosis of apical periodontitis (AP).

Methods: One hundred thirty-four premolar root canals from 10 dogs were treated after AP induction. Four months later, the animals were killed, and standard digital PRs were obtained. The area of AP was measured by using ImageJ software. CBCT (i-CAT) images from each arch were obtained, and AP area and volume were measured by using Osiri-X software. The apical inflammatory infiltrate was evaluated under light microscopy. The correlation between imaging methods was evaluated by using the Pearson coefficient. The Bland-Altman method was used to assess the agreement between PR and CBCT data. The Spearman coefficient was used to correlate the imaging data and histologic findings.

Results: Despite a strong correlation between PR and CBCT areas, the agreement limits were very broad (95% limits of agreement, 0.19-1.08). PR only measured, on average, 63% of CBCT values. Although there was a strong correlation between PR area and CBCT volume, the Bland-Altman method suggests that the larger the CBCT volume, the more underestimated the PR value. When APs had a volume smaller than 6 mm(3), the PR estimation of CBCT data was unpredictable. A positive correlation was found for PR area, CBCT area, CBCT volume, and histology data.

Conclusions: The diagnosis of AP based on PR data is clinically limited, and it should not be used for scientific investigations.
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http://dx.doi.org/10.1016/j.joen.2014.09.003DOI Listing
December 2014

Influence of ultrasonic activation on photodynamic therapy over root canal system infected with Enterococcus faecalis--an in vitro study.

Photodiagnosis Photodyn Ther 2014 Dec 4;11(4):472-8. Epub 2014 Aug 4.

School of Dentistry, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil.

Aim: The purpose of this study was to evaluate, in vitro, the influence of ultrasonic activation on photodynamic therapy over root canal system infected with Enterococcus faecalis.

Material And Methods: The root canals of 50 single-rooted human extracted teeth were enlarged up to a file 60, autoclaved, inoculated with Enterococcus faecalis and incubated for 30 days. The samples were divided into five groups (n=10) according to the protocol of decontamination: G1 (control group) - no procedure was performed; G2 - photosensitizer (0.01% methylene blue); G3 - ultrasonic activation of photosensitizer (0.01% methylene blue); G4 - photodynamic therapy with no ultrasonic activation; and G5 - photodynamic therapy with ultrasonic activation. Microbiological tests (CFU counting) and scanning electron microscopy (SEM) were performed to evaluate and illustrate, respectively, the effectiveness of proposed treatments. Data were subjected to one-way ANOVA followed by post hoc Tukey test (α=0.05).

Results: The microbiological test demonstrated that G5 (photodynamic therapy with ultrasonic activation) showed the lowest mean contamination (3.17 log CFU/mL), which was statistically different from all other groups (p<0.05). G4 (photodynamic therapy) showed a mean of contamination of 3.60 log CFU/mL, which was statistically different from groups 1, 2 and 3 (p<0.05).

Conclusion: The use of ultrasonic activation on photodynamic therapy improved its potential for decontamination, resulting in the higher elimination Enterococcus faecalis from the root canal space.
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http://dx.doi.org/10.1016/j.pdpdt.2014.07.004DOI Listing
December 2014

Clinically relevant dimensions of 3-rooted maxillary premolars obtained via high-resolution computed tomography.

J Endod 2013 Dec 12;39(12):1639-45. Epub 2013 Sep 12.

Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.

Introduction: This study aimed to characterize the dimensions of a selection of 3-rooted maxillary premolars through high-resolution computed tomographic analysis considering measures of clinical interest for root canal treatment, such as root wall thickness, canal diameters, and distances between 2 canals in fused roots and between the root apex and foramen.

Methods: Fifteen 3-rooted human maxillary premolars extracted for therapeutic reasons were individually scanned using a high-resolution desktop high-resolution computed tomographic system. Starting from the apical foramen, the selected cross-sectional images corresponding to each millimeter of the roots were evaluated. Measures of clinical interest were determined using Image J software (version 1.41; National Institutes of Health, Bethesda, MD).

Results: Root wall thickness as thin as 0.4 and 0.6 mm was detected in the apical portion of buccal and palatal roots, respectively. In the cervical portion, buccal roots had narrower root walls (0.817-1.670 mm) compared with palatal roots (1.361-2.720 mm). In all thirds, the palatal canal was wider compared with the mesiobuccal and distobuccal canals. In the buccopalatal direction, all roots had thicker root walls toward the furcation, whereas in the mesiodistal direction the mesiobuccal and distobuccal roots had the thinnest walls along their distal and mesial aspects, respectively. Both buccal canals revealed dentin apposition 2 mm from the canal orifice, resulting in cervical constriction. Generally, the distance between the root apex and the foramen was greater in distobuccal roots in comparison with the others with a tendency for foramina to be eccentric.

Conclusions: Three-rooted premolars are a clinical challenge not just because of their low frequency and difficulties regarding diagnosis and root canals access but also because of their fragile roots. These phenomena are critical in terms of the amount of dentin removed during the preparation of root canals and during post space preparation.
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http://dx.doi.org/10.1016/j.joen.2013.07.029DOI Listing
December 2013