Antibacterial Activity of Epigallocatechin-3-gallate (EGCG) Loaded Lipid-chitosan Hybrid Nanoparticle against Planktonic Microorganisms.

Epigallocatechin-3-gallate (EGCG), a polyphenol derived from Green Tea, is one of the sources of natural bioactive compounds which are currently being developed as medicinal ingredients. Besides other biological activities, this natural compound exhibits anti-cariogenic effects. However, EGCG has low physical-chemical stability and poor bioavailability. Thus, the purpose of this study was to develop and characterize lipid-chitosan hybrid nanoparticle with EGCG and to evaluate its in vitro activity against cariogenic planktonic microorganisms. Lipid-chitosan hybrid nanoparticle (LCHNP-EGCG) were prepared by emulsion and sonication method in one step and characterized according to diameter, polydispersity index (PdI), zeta potential (ZP), encapsulation efficiency (EE), mucoadhesion capacity and morphology. Strains of Streptococcus mutans, Streptococcus sobrinus and Lactobacillus casei were treated with LCHNP- EGCG, and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated. LCHNP-EGCG exhibited a size of 217.3 ± 5.1 nm with a low polydispersity index (0.17) and positive zeta potential indicating the presence of chitosan on the lipid nanoparticle surface (+33.7 mV). The LCHNP-EGCG showed a spherical morphology, high stability and a mucoadhesive property due to the presence of chitosan coating. In addition, the EGCG encapsulation efficiency was 96%. A reduction of almost 15-fold in the MIC and MBC against the strains was observed when EGCG was encapsulated in LCHNP, indicating the potential of EGCG encapsulation in lipid-polymer hybrid nanoparticles. Taking the results together, the LCHNP-EGCG could be an interesting system to use in dental care due to their nanometric size, mucoadhesive properties high antibacterial activity against relevant planktonic microorganisms.

Effect of EGCG-based paste as intracanal dressing, in MMPs 2 and 9 expression in dog's periapical lesions.

High expression of MMP-2 and MMP-9 in periapical lesions plays an important role in the degradation of the extracellular matrix. This study aimed to investigate the effect of epigallocatechin-3-gallate (EGCG)-based endodontic paste as an intracanal dressing on the expression of MMP-2 and MMP-9 in periapical lesions. Periapical lesions were experimentally induced in 35 mature beagle dog premolars randomly divided into healthy teeth, untreated periapical lesions, periapical lesions treated in a single session (control groups), and periapical lesions treated in two sessions with EGCG or calcium hydroxide-based pastes (experimental groups). After 120 days, specimens were obtained for histopathologic and immunofluorescence analyses to assess the expression of MMP-2 and MMP-9. The statistical analysis was performed using a p-value of 0.05. Endodontic treatment in two sessions using medication with EGCG and calcium hydroxide-based pastes provided similar repair of the apical and periapical tissues and neoformation of periodontal ligament fibers, cementum, and alveolar bone (p>0.05). The experimental groups treated in two sessions with both medications presented expression of MMP-2 and MMP-9 similar to that in healthy teeth (p>0.05), and significantly lower than teeth treated in a single session or untreated periapical lesions (p <0.001). Expression of MMP-2 and MMP-9 was observed in the cytoplasm of fibroblasts, osteoblasts, cementoblasts, cementocytes, and vascular endothelium. The use of EGCG-based endodontic paste reduced the expression of MMP-2 and MMP-9 and allowed repair of periapical lesions, similar to calcium hydroxide-based paste, and superior to treatment performed in a single session.

Effect of EGCG-based paste as intracanal dressing, in MMPs 2 and 9 expression in dog's periapical lesions

Abstract High expression of MMP-2 and MMP-9 in periapical lesions plays an important role in the degradation of the extracellular matrix. This study aimed to investigate the effect of epigallocatechin-3-gallate (EGCG)-based endodontic paste as an intracanal dressing on the expression of MMP-2 and MMP-9 in periapical lesions. Periapical lesions were experimentally induced in 35 mature beagle dog premolars randomly divided into healthy teeth, untreated periapical lesions, periapical lesions treated in a single session (control groups), and periapical lesions treated in two sessions with EGCG or calcium hydroxide-based pastes (experimental groups). After 120 days, specimens were obtained for histopathologic and immunofluorescence analyses to assess the expression of MMP-2 and MMP-9. The statistical analysis was performed using a p-value of 0.05. Endodontic treatment in two sessions using medication with EGCG and calcium hydroxide-based pastes provided similar repair of the apical and periapical tissues and neoformation of periodontal ligament fibers, cementum, and alveolar bone (p>0.05). The experimental groups treated in two sessions with both medications presented expression of MMP-2 and MMP-9 similar to that in healthy teeth (p>0.05), and significantly lower than teeth treated in a single session or untreated periapical lesions (p <0.001). Expression of MMP-2 and MMP-9 was observed in the cytoplasm of fibroblasts, osteoblasts, cementoblasts, cementocytes, and vascular endothelium. The use of EGCG-based endodontic paste reduced the expression of MMP-2 and MMP-9 and allowed repair of periapical lesions, similar to calcium hydroxide-based paste, and superior to treatment performed in a single session.

Resumo A alta expressão de MMP-2 e MMP-9 em lesões periapicais desempenha um papel importante na degradação da matriz extracelular. Este estudo teve como objetivo investigar o efeito de uma pasta à base de epigalocatequina-3-galato (EGCG) como curativo intracanal na expressão de MMP-2 e MMP-9 em lesões periapicais. Lesões periapicais foram induzidas experimentalmente em 35 pré-molares de cães da raça beagle, maduros, divididos aleatoriamente em dentes saudáveis, lesões periapicais não tratadas, lesões periapicais tratadas em uma única sessão e lesões periapicais tratadas em duas sessões com a pasta de EGCG ou pasta à base de hidróxido de cálcio. O operador monitorou os animais e realizou a eutanásia após 120 dias para análises histopatológicas e de imunofluorescência para avaliar a expressão de MMP-2 e MMP-9. A análise estatística foi realizada utilizando p=0,05. O tratamento endodôntico em duas sessões com pasta à base de EGCG e pasta à base de hidróxido de cálcio proporcionou níveis semelhantes de reparação dos tecidos apicais e periapicais e neoformação de fibras do ligamento periodontal, cemento e osso alveolar. Em ambos os grupos, a expressão de MMP-2 e MMP-9 foi mínima, sendo observada no citoplasma de fibroblastos, osteoblastos, cementoblastos, cementócitos e endotélio vascular. Em ambos os grupos tratados em duas sessões, a expressão de MMP-2 e MMP-9 foi semelhante à dos dentes hígidos e significativamente menor do que nas lesões periapicais tratadas em sessão única ou não tratadas (p < 0,001). O uso da pasta à base de EGCG reduziu a expressão de MMP-2 e MMP-9 e permitiu o reparo de lesões periapicais, semelhante à pasta à base de hidróxido de cálcio, e foi superior ao tratamento realizado em sessão única.

Agentes e métodos de descontaminação das escovas dentais - Uma revisão sistemática / Decontamination agents and methods of toothbrushes - A systematic review

Objetivo: Realizar uma revisão sistemática para avaliar os principais agentes e métodos de descontaminação das escovas dentais contra vírus, bactérias e fungos encontrados na literatura. Métodos: Foi realizada uma busca nas bases de dados LILACS® (Literatura científica e técnica da América Latina e Caribe/BVS ­ Biblioteca Virtual em Saúde), MEDLINE® (Medical Literature Analysis and Retrieval System Online / PubMed)®, EMBASE® (Elsevier), em agosto de 2020. Como critério de inclusão, foram selecionados artigos publicados entre os anos de 2010 e 2020, nos idiomas português, inglês e espanhol, estudos de ensaios clínicos controlados randomizados, ensaios clínicos não randomizados e estudos in vitro, que avaliaram diferentes agentes e métodos de descontaminação das escovas dentais. Resultados: Foram recuperados um total de 2523 artigos, sendo qualificados para o estudo um total de 6 artigos "in vivo" e 4 "in vitro". O agente de descontaminação mais estudado e eficaz foi a clorexidina 0,12% (em forma de imersão ou spray), seguida pelo hipoclorito de sódio 1% e 2,5% (imersão), vinagre branco 50% (imersão), solução de cloreto de cetilpiridínio (imersão ou spray), micro-ondas e máquina de lavar-louças. Conclusão: Considerando as evidências de qualidade encontradas, a clorexidina 0,12% constitui o agente mais estudado e eficaz, seguido pelo hipoclorito de sódio 1 % e cloreto de cetilpiridínio, utilizados em forma de spray ou imersão, constituem soluções eficazes, de fácil acesso, que podem ser utilizadas pela população para descontaminação das escovas dentais.

Aim: To carry out a systematic review of articles found in the literature in order to evaluate the main agents and methods for decontaminating toothbrushes against viruses, bacteria, and fungi. Methods: A search was performed in LILACS® (Scientific and Technical Literature of Latin America and the Caribbean/VHL ­ Virtual Health Library), MEDLINE® (Medical Literature Analysis and Retrieval System Online /PubMed)®, and EMBASE® databases (Elsevier), in August 2020. As inclusion criteria, articles published between 2010 and 2020, in Portuguese, English, and Spanish, studies of randomized controlled clinical trials, non-randomized clinical trials, and in vitro studies were selected, which evaluated different agents and methods for decontaminating toothbrushes. Results: A total of 2,523 articles were retrieved, with a total of 6 in vivo and 4 in vitro articles deemed to be eligible for the study. The most studied and effective decontamination agent was 0.12% chlorhexidine (in immersion or spray form), followed by 1% and 2.5% sodium hypochlorite (immersion), 50% white vinegar (immersion), solution of cetylpyridinium chloride (dip or spray), microwave, and dishwasher. Conclusion: Considering the quality evidence found, 0.12% chlorhexidine is the most studied and effective agent, followed by 1% sodium hypochlorite and cetylpyridinium chloride, used in spray or immersion form; these are effective, easily accessible solutions that can be used by the population to decontaminate toothbrushes.

In Vivo Detection of External Apical Root Resorption Induced by Apical Periodontitis Using Periapical Radiography and Cone-Beam Computed Tomography

Abstract Objective: To compare the accuracy of periapical radiography (PR) and cone-beam computed tomography (CBCT) for the detection of external apical root resorption (EARR) due to root canal contamination. Material and Methods: Dog's teeth with experimentally induced root resorption due to root canal contamination underwent or not root canal treatment (n=62). True positives (TP), false positives (FP), true negatives (TN), and false negatives (FN) in PR and CBCT diagnoses were determined using histopathologic findings as the gold standard. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy (TP + TN) in the diagnosis of EARR were calculated. Data were compared using chi-squared test (α=0.05). Results: EARR was detected in 35% of roots by PR, in 47% by CBCT, and in 50% of the roots by microscopy (p=0.03 PR versus microscopy; p=0.67 CBCT versus microscopy). Overall, CBCT produced more accurate diagnoses than PR (p=0.008). PR and CBCT allowed the identification of large resorption in 100% of the cases and showed the same accuracy. However, for small resorptions, PR showed an accuracy of 0.83, whereas CBCT showed an accuracy of 0.96 (p=0.003). Conclusion: Cone-beam computed tomography showed higher accuracy in detecting external apical root resorption of endodontic origin.

MMP2 and MMP9 are Associated with Apical Periodontitis Progression and Might be Modulated by TLR2 and MyD88

Abstract The aim of this study was to evaluate the expression of MMP2 and MMP9 during apical periodontitis (AP) progression in TLR2 (TLR2 KO) and in MyD88 (MyD88 KO) knockout mice compared to wild type (WT) mice. AP was induced in mandibular first molars of TLR2 KO (n= 18), MyD88 KO (n= 18), and WT mice (n= 18). After 7, 21, and 42 days, the animals were euthanized and the jaws were dissected and subjected to histotechnical processing. Subsequent sections were stained by immunohistochemistry and evaluated for detection of MMP2 and MMP9. Statistical analysis of the semi-quantitative analysis of immunohistochemistry was performed using chi-square test (α = 0.05). In the initial periods of AP progression, an increased expression of MMP9 in the TLR2 KO and MyD88 KO mice was observed. In the final periods of AP progression, a reduction of MMP2 expression and an increase of MMP9 expression in the TLR2 KO mice were observed. MMP2 and MMP9 production was modulated for TLR2 and MyD88 during apical periodontitis progression.

Resumo O objetivo deste estudo foi avaliar a expressão de MMP2 e MMP9 durante a progressão da periodontite apical (AP) em camundongos knockout para TLR2 (TLR2 KO) e MyD88 (MyD88 KO) comparados aos camundongos wild type (WT). A AP foi induzida nos primeiros molares inferiores dos camundongos TLR2 KO (n = 18), MyD88 KO (n = 18) e WT (n = 18). Após 7, 21 e 42 dias, os animais foram eutanaziados e as mandíbulas foram dissecadas e submetidas a processamento histotécnico. As lâminas foram coradas por imuno-histoquímica e analisadas para a detecção de MMP2 e MMP9. A análise estatística semi-quantitativa da imuno-histoquímica foi realizada pelo teste qui-quadrado (α = 0,05). Nos períodos iniciais de progressão AP, foi observada uma expressão aumentada de MMP9 nos camundongos TLR2 KO e MyD88 KO. Nos períodos finais de progressão AP, observou-se uma redução da expressão de MMP2 e um aumento da expressão de MMP9 nos camundongos TLR2 KO. A produção de MMP2 e MMP9 foi modulada por TLR2 e MyD88 durante a progressão da periodontite apical.

MMP2 and MMP9 are Associated with Apical Periodontitis Progression and Might be Modulated by TLR2 and MyD88.

The aim of this study was to evaluate the expression of MMP2 and MMP9 during apical periodontitis (AP) progression in TLR2 (TLR2 KO) and in MyD88 (MyD88 KO) knockout mice compared to wild type (WT) mice. AP was induced in mandibular first molars of TLR2 KO (n= 18), MyD88 KO (n= 18), and WT mice (n= 18). After 7, 21, and 42 days, the animals were euthanized and the jaws were dissected and subjected to histotechnical processing. Subsequent sections were stained by immunohistochemistry and evaluated for detection of MMP2 and MMP9. Statistical analysis of the semi-quantitative analysis of immunohistochemistry was performed using chi-square test (α = 0.05). In the initial periods of AP progression, an increased expression of MMP9 in the TLR2 KO and MyD88 KO mice was observed. In the final periods of AP progression, a reduction of MMP2 expression and an increase of MMP9 expression in the TLR2 KO mice were observed. MMP2 and MMP9 production was modulated for TLR2 and MyD88 during apical periodontitis progression.

Validation of pH cycling model to induce artificial carious lesions in bovine dentin

Introduction and objective:The purpose of the study was to evaluate different pH cycling protocols on the induction of artificial carious lesions in bovine dentin, since the most appropriate protocol to be applied is still not fully established. Material and methods: Fragments of bovine dentin (4 x 4 x 2 mm) were embedded in resin, polished and 7 mm² of each fragment was isolated with wax. The specimens were divided into three groups (A, B, C) according to the time of immersion in the demineralizing solution (1.5 ml). Group A - 15 minutes; Group B - 30 minutes; Group C - 60 minutes and subsequently immersed for 22 hours in a remineralizing solution (1.5 ml). Microhardness measurements were conducted initially, daily and after each pH cycling for 4 days. The Split-plot design (ANOVA) was applied. Results: There was a significant interaction between time and cariogenic challenge (p<0.0001). Bonferroni comparisons were executed to identify the differences over the cariogenic challenge, showing that increasing the immersion time in demineralizing solution for each pH cycling assessed, the cariogenic challenge aggressiveness increased (A

Localized aggressive periodontitis - clinical, radiographic, microbiological and immunological findings

Introduction: Localized Aggressive Periodontitis (LAP) is characterized by a disease with rapid progression and loss of bone support specifically in the region of the permanent first molars and incisors teeth, and may lead to loss of dental elements. Objective: The aim of this study was to conduct a brief literature review on LAP, and present the clinical, radiographic, microbiological and immunological aspects of this rare form of periodontal disease. Literature review: Epidemiological studies in different populations showed a higher incidence in non-white population, and non-industrialized countries, there is also a predilection for female gender, manifested between puberty and 25 to 30 years of age. Conclusion: LAP is a disease with low prevalence, mainly caused by Aa, and radiographically manifested by extensive destruction of periodontal tissue supporting of permanent first molars and incisors. In contrast, clinically, the affected teeth not presented significant amount of dental biofilm or gingival inf lammation. The early diagnosis is important to establish an effective treatment, including antibiotic therapy, and favor prognosis.

Role of endotoxin in the etiology of periapical lesions: molecular mechanisms involved in endotoxin's recognition and cell activation / Papel da endotoxina na etiologia da lesão periapical: mecanismos moleculares envolvidos no seu reconhecimento e na ativação celular

Periapical lesions are diseases resulting from contamination and necrosis of dental pulp and the progression of this infection toward the periapical tissues. Technological advances in microbiological culture and identification have shown that anaerobic microorganisms, especially Gram-negative, are predominate in root canals of teeth with pulp necrosis and chronic periapical lesions. Gram-negative bacteria not only have different factors of virulence and generate products and sub-products that are toxic to apical and periapical tissues, but also contain endotoxin in the outer membrane of their cell wall. This information is important because endotoxin is released during multiplication or bacterial death, causing a series of biological effects that lead to an inflammatory reaction and resorption of mineralized tissues. Thus, the aim of this work is to carry out a review of the literature on the role of bacterial endotoxin in the etiology of periapical lesions, its mechanism of action, and to elucidate molecular mechanisms involved in endotoxin's recognition by the immune system and cell activation.

As lesões periapicais são patologias resultantes da contaminação e necrose da polpa dental e progressão da infecção em direção aos tecidos periapicais. Os avanços tecnológicos na cultura e identificação microbiana demonstraram que, em canais radiculares de dentes portadores de necrose pulpar e lesão periapical crônica, predominam os microrganismos anaeróbios, particularmente os Gram-negativos. As bactérias Gram-negativas, além de possuírem diferentes fatores de virulência e gerarem produtos e subprodutos tóxicos aos tecidos apicais e periapicais, contêm a endotoxina em sua parede celular. Esse conhecimento é importante, uma vez que a endotoxina é liberada durante a multiplicação ou morte bacteriana, exercendo uma série de efeitos biológicos relevantes, que conduzem a uma reação inflamatória e à reabsorção dos tecidos mineralizados. Sendo assim, o objetivo deste trabalho foi efetuar uma revisão da literatura relativa ao papel da endotoxina bacteriana na etiologia das lesões periapicais, seu mecanismo de ação, bem como elucidar mecanismos moleculares envolvidos no seu reconhecimento pelo sistema imunológico e na ativação celular.

Antimicrobial Activity of Toothpastes Containing Natural Extracts, Chlorhexidine or Triclosan

Abstract: The objective of this in vitro study was to evaluate the antimicrobial effect of toothpastes containing natural extracts, chlorhexidine or triclosan. The effectiveness of toothpastes containing natural extracts (Parodontax(r)), 0.12% chlorhexidine (Cariax(r)), 0.3% triclosan (Sanogil(r)) or fluoride (Sorriso(r), control) was evaluated against yeasts, Gram-positive and Gram-negative bacteria using the disk diffusion method. Water was used as a control. Disks impregnated with the toothpastes were placed in Petri dishes containing culture media inoculated with 23 indicative microorganisms by the pour plate method. After incubation, the inhibition growth halos were measured and statistical analyses (α=0.05) were performed. The results indicated that all formulations, except for conventional toothpaste (Sorriso(r)), showed antimicrobial activity against Gram-positive bacteria and yeasts. The toothpaste containing natural extracts (Parodontax(r)) was the only product able to inhibit the growth of Pseudomonas aeruginosa. The toothpastes containing chlorhexidine, triclosan or natural extracts presented antimicrobial activity against Gram-positive bacteria and yeasts.

Resumo: O objetivo deste estudo in vitro foi avaliar o efeito antimicrobiano de dentifrícios contendo extratos naturais, clorexidina ou triclosan. A efetividade dos dentifrícios contendo extratos naturais (Parodontax(r)), 0,12% de clorexidina (Cariax(r)), 0,3% de triclosan (Sanogil(r)) ou flúor (Sorriso(r), controle) foi avaliada contra leveduras, bactérias Gram-positivas e Gram-negativas utilizando o método de difusão em disco. A água foi utilizada como um controle. Discos impregnados com os dentifrícios foram colocados em placas de Petri contendo meio de cultura inoculados com 23 microrganismos indicadores pelo método "pour plate". Após a incubação, os halos de inibição do crescimento foram medidos e as análises estatísticas (=0,05) foram realizadas. Os resultados indicaram que todas as formulações, com exceção do dentifrício convencional (Sorriso(r)), apresentaram atividade antimicrobiana contra bactérias Gram-positivas e leveduras. O dentifrício contendo extratos naturais (Parodontax(r)) foi o único produto capaz de inibir o crescimento de Pseudomonas aeruginosa. Os dentifrícios contendo clorexidina, triclosan ou extratos naturais apresentaram atividade antimicrobiana contra bactérias Gram-positivas e leveduras.

Gubernacular cord and canal: does these anatomical structures play a role in dental eruption?

Introduction: The gubernacular cord is an original structure of the dental lamina, which undergoes apoptosis and their remnants were organized in the form of epithelial islets and strands that lined up, leaving the reduced epithelium of the enamel organ towards the oral mucosa. This structure is located within the gubernacular canal, which can be identified as a small opening in the alveolar region of the lingual or palatal surface of the deciduous teeth. Objective: To conceptualize, identify and assess the possible contribution of the gubernacular cord and canal in the process of tooth eruption. Literature review: A review of literature on Pubmed, Medline and Bireme databases, without datum restriction. Little amount of scientific articles were found, and only 14 studies were identified. The authors addressed the matter succinctly, with little information about these structures, which can play an important role in the process of tooth eruption. Conclusion: The gubernacular cord and canal are anatomical structures located in the alveolar bone crest of the maxilla or mandible, behind the deciduous teeth. These structures appear to exhibit the ability to aid the eruption path of the permanent teeth successors. Despite being a relevant subject, few professionals know this structure and its possible role in the process of tooth eruption.

Eruption sequestrum - case report and histopathological findings

Eruption sequestrum is an uncommon disturbance in eruption and consists of small fragments of calcified tissue overlying the crowns of erupting permanent molar teeth, especially at the time of eruption of the mandibular first molars. This paper reports a case of unilateral eruption sequestrum in a 7-year-old Brazilian boy and describes its histopathological findings. A white small fragment, 0.5 cm in diameter, with hard consistency, irregular shape and located on the occlusal surface of the erupting mandibular left first molar was excised. Microscopic examination revealed large trabeculae with empty lacunae and a minimal amount of existing spongy bone consisting of acute inflammatory cells (neutrophils). Signs of necrosis were found on the periphery. The histological analysis was consistent with non-vital bone and the diagnosis of eruption sequestrum was established. Clinical and radiographic follow-up visits scheduled at short intervals and then every 6 months revealed normal postoperative conditions.

Sequestro de erupção é um distúrbio raro da erupção e consiste de pequenos fragmentos de tecido calcificado que envolvem as coroas dos dentes molares permanentes em erupção, principalmente no momento da erupção dos primeiros molares inferiores. O objetivo deste trabalho é relatar um caso unilateral de sequestro de erupção em um menino brasileiro de 7 anos de idade e descrever seus achados histopatológicos. Um fragmento branco e pequeno, de 0,5 cm de diâmetro, com consistência dura, de forma irregular e localizado na superfície oclusal do primeiro molar inferior esquerdo em erupção foi excisado. O exame microscópico revelou trabéculas grandes com lacunas vazias e uma quantidade mínima de osso esponjoso existente consistindo de células inflamatórias agudas (neutrófilos). Na periferia, sinais de necrose foram evidenciados. A análise histológica foi consistente com osso não-vital e o diagnóstico de sequestro de erupção foi estabelecido. Exames clínicos e radiográficos em intervalos curtos e posteriormente semestrais revelaram condições pós-operatórias normais.

Skeletal alterations associated with the use of bonded rapid maxillary expansion appliance.

Bonded maxillary expansion appliances have been suggested to control increases in the vertical dimension of the face after rapid maxillary expansion (RME). However, there is still no consensus in the literature about its real skeletal effects. The purpose of this prospective study was to evaluate, longitudinally, the vertical and sagittal cephalometric alterations after RME performed with bonded maxillary expansion appliance. The sample consisted of 26 children, with a mean age of 8.7 years (range: 6.9-10.9 years), with posterior skeletal crossbite and indication for RME. After maxillary expansion, the bonded appliance was used as a fixed retention for 3.4 months, being replaced by a removable retention subsequently. The cephalometric study was performed onto lateral radiographs, taken before treatment was started, and again 6.3 months after removing the bonded appliance. Intra-group comparison was made using paired t test. The results showed that there were no significant sagittal skeletal changes at the end of treatment. There was a small vertical skeletal increase in five of the eleven evaluated cephalometric measures. The maxilla displaced downward, but it did not modify the facial growth patterns or the direction of the mandible growth. Under the specific conditions of this research, it may be concluded that RME with acrylic bonded maxillary expansion appliance did promote signifciant vertical or sagittal cephalometric alterations. The vertical changes found with the use of the bonded appliance were small and probably transitory, similar to those occurred with the use of banded expansion appliances.

Skeletal alterations associated with the use of bonded rapid maxillary expansion appliance

Bonded maxillary expansion appliances have been suggested to control increases in the vertical dimension of the face after rapid maxillary expansion (RME). However, there is still no consensus in the literature about its real skeletal effects. The purpose of this prospective study was to evaluate, longitudinally, the vertical and sagittal cephalometric alterations after RME performed with bonded maxillary expansion appliance. The sample consisted of 26 children, with a mean age of 8.7 years (range: 6.9-10.9 years), with posterior skeletal crossbite and indication for RME. After maxillary expansion, the bonded appliance was used as a fixed retention for 3.4 months, being replaced by a removable retention subsequently. The cephalometric study was performed onto lateral radiographs, taken before treatment was started, and again 6.3 months after removing the bonded appliance. Intra-group comparison was made using paired t test. The results showed that there were no significant sagittal skeletal changes at the end of treatment. There was a small vertical skeletal increase in five of the eleven evaluated cephalometric measures. The maxilla displaced downward, but it did not modify the facial growth patterns or the direction of the mandible growth. Under the specific conditions of this research, it may be concluded that RME with acrylic bonded maxillary expansion appliance did promote signifciant vertical or sagittal cephalometric alterations. The vertical changes found with the use of the bonded appliance were small and probably transitory, similar to those occurred with the use of banded expansion appliances.

Os aparelhos disjuntores com cobertura oclusal de acrílico têm sido sugeridos para controlar o aumento da dimensão vertical da face após a expansão rápida da maxila (ERM). Entretanto, ainda não há consenso na literatura sobre seu real efeito esquelético. O objetivo desse estudo prospectivo foi avaliar longitudinalmente as alterações esqueléticas verticais e sagitais após a ERM realizada com o aparelho disjuntor com cobertura oclusal. A amostra consistiu de 26 crianças, com idade média de 8,7 anos (variação: 6.9-10,9 anos), apresentando mordida cruzada posterior esquelética e indicação para ERM. Após a expansão maxilar, o aparelho foi utilizado como contenção fixa por 3,4 meses, sendo posteriormente substituído por uma contenção removível. O estudo cefalométrico foi realizado em telerradiografias laterais tomadas antes do início do tratamento e novamente 6,3 meses após a remoção do disjuntor. A comparação intragrupo foi feita utilizando-se o teste t pareado. Os resultados mostraram que não houve alterações esqueléticas sagitais significantes ao fim do tratamento. Houve um pequeno aumento em cinco das onze medidas cefalométricas verticais analisadas. A maxila se moveu inferiormente, porém não modificou o padrão de crescimento facial, a inclinação ou direção de crescimento mandibular. Considerando-se as condições específicas deste trabalho, pode-se concluir que a ERM realizada com o aparelho disjuntor com cobertura oclusal de acrílico não promoveu alterações esqueléticas verticais ou sagitais prejudiciais. As alterações verticais encontradas com o uso do aparelho colado foram pequenas e provavelmente transitórias, similar ao que ocorre com o uso dos aparelhos expansores bandados.

Mecanismos celulares e moleculares envolvidos na reabsorção radicular fisiológica de dentes decíduos / Cellular and molecular mechanisms involved in the physiological root resorption of primary teeth

Introdução: A reabsorção fisiológica dos dentes decíduos constitui um fenômeno fisiológico complexo não completamente conhecido; assunto de grande interesse clínico. Os mecanismos celulares e moleculares envolvidos no fenômeno de reabsorção radicular fisiológica parecem ser similares aos mecanismos envolvidos na reabsorção óssea, mediada por osteoclastos. As principais células responsáveis pela reabsorção ativa dos tecidos dentais são os odontoclastos, também denominados de clastos ou osteoclastos; células gigantes multinucleadas originadas de precursores hematopoiéticos de monócitos ou macrófagos. Avanços recentes na literatura específica têm mostrado que a diferenciação e atividade dos osteoclastos, fenômeno também conhecido como osteoclastogênese, são iniciadas e reguladas por diferentes estímulos e sinalizadores moleculares como as citocinas, quimiocinas, produtos de degradação liberados pela superfície radicular afetada, moléculas de adesão, metaloproteinases e pelo sistema RANK/RANKL/OPG. Ainda, o contato físico entre os precursores de osteoclastos e osteoblastos ou células estromais também parece ser necessário para a ativação da osteoclastogênese. Entretanto, o papel específico dos fatores envolvidos no início e modulação da reabsorção radicular dos dentes decíduos permanece desconhecido. Objetivo: Realizar uma revisão de literatura sobre os mecanismos celulares e moleculares envolvidos no processo de reabsorção fisiológica dos dentes decíduos, enfatizando suas implicações clínicas.

Conclusão: Uma complexa interação entre osteclastos, osteoblastos, macrófagos, citocinas, quimiocinas, metaloproteinases, moléculas de adesão e o sistema RANK/RANKL/OPG parecem contribuir para a reabsorção dentária fisiológica. O conhecimento dos mecanismos celulares e moleculares envolvidos no processo de reabsorção fisiológica dos dentes decíduos pode contribuir para o estudo da imunopatogenia das reabsorções dentárias e futuramente resultar na aplicação clínica de mediadores moleculares para atrasar ou mesmo inibir esse processo

Introduction: The physiological resorption of primary teeth is a complex physiological phenomenon that is not completely known and is a subject of great interest. The cellular and molecular mechanisms involved in the phenomenon of physiological root resorption seem to be similar to those involved in bone resorption mediated by osteoclasts. The main cells responsible for the active resorption of the dental tissues are the odontoclasts, which are also known as clasts or osteoclasts; multi nucleated giant cells originated from hematopoietic precursors of monocytes or macrophages. Recent advances published in the literature have shown that the differentiation and activity of osteoclasts, a phenomenon that is also known as osteoclastgenesis, are initiated and regulated by different stimuli and molecular signalizing agents such as cytokines, chemokines, products of degradation released by the affected root surface, adhesion molecules, metalloproteinases, and the RANK/RANKL/OPG system. Moreover, the physical contact between the osteoclasts and osteoblast precursors or stromal cells also seems to be necessary for the activation of osteoclastgenesis. However, the specific role of the factors involved in the initiation and modulation of root resorption of the primary teeth remains unknown. Objective: To perform a review of the literature about the cellular and molecular mechanisms involved in the process of physiological resorption of the primary teeth, emphasizing their clinical implications.

Conclusion: A complex integration among osteoclasts, osteoblasts, macrophages, cytokines, chemokines, metalloproteinases, adhesion molecules and the RANK/RANKL/OPG system seems to contribute to the physiological resorption of teeth. Knowing the cellular and molecular mechanisms involved in the process of physiological root resorption of primary teeth may contribute to the investigation of the immunepathogenesis of dental resorptions, and allow for the clinical application of molecular mediators to delay or even inhibit this process

Adequação do meio bucal e seu efeito sobre a microbiota salivar cariogênica / Clinical preventive procedures and its effect on cariogenic salivary microorganisms

O objetivo deste trabalho foi avaliar o efeito conjunto dos procedimentos clínicos de adequação do meio bucal sobre os níveis salivares de estreptococos do grupo mutans, em 18 crianças de 4 a 9 anos, apresentndo alto risco/atividade de cárie, com base em parâmetros clínicos/anamnésicos. Os procedimentos, realizados em única sessão, consistiram em instruções de higiene bucal, orientações dietéticas, aplicação de antimicrobiano, fluorterapia, escavação e selamento em massa das lesões cariosas e avulsão de raízes residuais. Amostras de saliva não estimulada foram coletadas previamente à realização dos procedimentos e após 7, 14 e 21 dias. Alíquotas de saliva pura e após diluição decimal seriada foram semeadas em meio SB20 modificado em incubadas em micoaerofilia durante 72 horas, a 37ºC. Após contagem do número de ufc do grupo mutans por mL de saliva, colônias caracteríticas foram submetidas à biotipagem (provas bioquímicas). Os resultados foram submetidos à análise estatítica empregando os testes de Friedman e Dunn. Observou-se uma redução estatisticamente significante nas contagens salivares de estrptococos do grupo mutans 7 (p<0,01), 14 (p<0,01) e 21 (p<0,05) dias após a adequação do meio bucal, não havendo diferença estatisticamente significante entre os períodos 7, 14 e 21 dias (p>0,05). Observou-se uma redução média, após 21 dias, de 61% nas contagens salivares de estreptococos do grupo mutans, sendo 64% de redução para S. mutans e 49% para S. sobrinus. Pôde-se concluir que a realização dos procedimentos clínicos de adequação do meio bucal reduziu os níveis salivares de estreptococos do grupo mutans por até 21 dias.