Bacteria of healthy periodontal tissues as candidates of probiotics: a systematic review.

OBJECTIVES: The use of probiotics could promote the balance of the subgingival microbiota to contribute to periodontal health. This study aimed to identify the potential of bacteria commonly associated with healthy periodontal tissues as probiotic candidates. MATERIAL AND METHODS: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using the PubMed, Scopus, Science Direct, ProQuest, and Ovid databases as well as the combination of Medical Subject Headings (MeSH) and non-MeSH terms. Based on the selection criteria, original studies published in English and identifying the microorganisms present in the periodontium of healthy individuals and patients with periodontitis using the high-throughput 16S ribosomal gene sequencing technique were included. RESULTS: Out of 659 articles, 12 met the criteria for this review. These articles were published from 2012 to 2020 and mainly originated from the United States, China, and Spain. Most of these studies reported adequate criteria for selecting participants, using standardized clinical criteria, and compliance with quality based on the tools used. In periodontal healthy tissue were identified species like Actinomyces viscosus, Actinomyces naeslundii, Haemophilus parainfluenzae, Rothia dentocariosa, Streptococcus sanguinis, Streptococcus mitis, Streptococcus oralis, Streptococcus gordonii, Streptococcus intermedius, and Prevotella nigrescens which have recognized strains with a capacity to inhibit periodontopathogens. CONCLUSIONS: S. sanguinis, S. oralis, S. mitis, and S. gordonii are among the bacterial species proposed as potential probiotics because some strains can inhibit periodontopathogens and have been reported as safe for humans.

Evaluation of periodontal parameters on abutment teeth rehabilitated with single-unit crowns: A 12-month follow-up.

Purpose: This prospective study evaluated the effects of the metal-free crowns on the periodontal tissues of abutment teeth during a 12-month follow-up. Materials and Methods: A sample of 24 patients (N = 32 abutment teeth) who needed a single-tooth restoration were enrolled to receive either a metal-ceramic (n = 21) or lithium disilicate (n = 11). The single-unit crowns were evaluated at baseline, 3-and 12-month follow-up. The periodontal parameters were evaluated: plaque index (PI), gingival bleeding index (GBI), bleeding on probing (BOP), probing depth (PD), clinical attachment loss (CAL), radiographically and clinical crown fitting, bone resorption, and marginal finish lines. Statistical analyses were performed using the Exact Fisher and Mann-Whitney tests, and the Wilcoxon signed-rank test as a post hoc test for Friedman (95 % confidence interval). Results: The marginal finish line showed a statistical difference with a biomaterial type (p =.004). After a 12-months, a significant increase was observed in PI and mean PD for abutment teeth of metal-ceramic crowns. The metal-free crowns presented higher values for GBI and CAL (p2 < 0.05). Only distal cervical evaluation and dental biofilm formation in the abutment teeth showed a statistical difference between the groups at the 12-month follow-up. The supragingival margin metal-ceramic group revealed higher PI values (p2 = 0.005) between the period and the subgingival margin of both biomaterials showed greater GBI scores (p2 < 0.05). Conclusions: Metal-free crowns showed better periodontal outcomes compared to metal-ceramic crowns. Single-unit crown marginal location affects the periodontal tissue condition of the abutment teeth. The marginal fit was not changed regarding the biomaterial type.

Tratamento do sorriso gengival por meio da cirurgia periodontal: relato de caso / Treatment of gummy smile through periodontal surgery: case report

A busca por um sorriso considerado perfeito tem sido cada vez maior e isso tem se tornado um desafio para o Cirurgião-Dentista, visto que um sorriso harmônico não envolve somente dentes, mas também gengiva. A exposição excessiva da gengiva ao sorrir ou falar é considerada uma característica antiestética, pois gera uma desarmonia entre dentes, gengiva e lábios. Quando o paciente expõe 3 milímetros ou mais de gengiva ao sorrir, chamamos essa exposição de Sorriso Gengival. O presente trabalho tem como objetivo relatar o tratamento de um caso de sorriso gengival, onde foi realizada cirurgia periodontal ressectiva a fim de diminuir a exposição de tecido gengival ao sorrir. Descrição do caso: Paciente adulto 21 anos, sexo masculino, procurou atendimento no curso de graduação em Odontologia do Centro Universitário da Serra Gaúcha ­ FSG, com queixa de insatisfação estética devido ao tamanho de seus dentes e mostrar muito tecido Gengival ao sorrir. Após anamnese, exame clínico e radiográfico, o paciente foi diagnosticado com Sorriso gengival. O plano de tratamento proposto foi de cirurgia periodontal ressectiva. Conclusão: A partir do exposto, podemos concluir que o tratamento do sorriso gengival depende de sua etiologia. Um correto diagnóstico é de extrema importância, pois dependendo do fator etiológico do sorriso gengival, o plano de tratamento pode ser elaborado de acordo com a necessidade do paciente. No caso apresentado, o procedimento escolhido, cirurgia periodontal ressectiva, se mostrou efetivo no tratamento do sorriso gengival, devolvendo estética e satisfação ao paciente(AU)

The search for a smile that is considered perfect has been increasing and this has become a challenge for the Dental Surgeon, since a harmonious smile does not only involve teeth, but also gums. Excessive exposure of the gums when smiling or talking is considered an unsightly feature, as it creates disharmony between teeth, gums and lips. When the patient exposes 3 millimeters or more of gum when smiling, we call this exposure Gummy Smile. The present work aims to report the treatment of a case of gummy smile, where resective periodontal surgery was performed in order to reduce the exposure of gingival tissue when smiling. Case description: A 21-year-old adult patient, male, sought care at the undergraduate course in dentistry at the Centro Universitário da Serra Gaúcha ­ FSG, complaining of aesthetic dissatisfaction due to the size of his teeth and showing a lot of gingival tissue when smiling. After anamnesis, clinical and radiographic examination, the patient was diagnosed with gummy smile. The proposed treatment plan was resective periodontal surgery. Conclusion: From the above, we can conclude that the treatment of gummy smile depends on its etiology. A correct diagnosis is extremely important, because depending on the etiological factor of the gummy smile, the treatment plan can be elaborated according to the patient's needs. In the case presented, the chosen procedure, resective periodontal surgery, proved to be effective in the treatment of gummy smile, restoring aesthetics and patient satisfaction(AU)

Dental and periodontal dimensions stability after esthetic clinical crown lengthening surgery: a 12-month clinical study.

OBJECTIVES: To evaluate the stability of periodontal tissues 3 (T3), 6 (T6), and 12 (T12) months after esthetic crown lengthening (ACL) and the possible correlations between changes in those structures. MATERIALS AND METHODS: Twenty individuals were evaluated through clinical assessment, photography, and tomography. Measurements included gingival margin (GM), clinical crown length (CCL), interdental papilla height (PH) and width (PW), gingival thickness (GT), bone thickness (BT), probing depth (PD), distance between alveolar crest and GM, distance between alveolar crest and cementoenamel junction. Nonparametric and correlation statistics were performed (p < 0.05). RESULTS: CCL at T0 was 7.42 ± 0.70 mm and increased to 9.48 ± 0.49 mm immediately after ACL, but it decreased to 8.93 ± 0.65 mm at T12. PD decreased 0.60 mm from T0 to T6, and it increased 0.39 mm from T6 to T12. BT decreased 0.20 mm, while GT increased 0.29 mm from T0 to T12. Both PW and PH showed enlargement in T12. A positive moderate correlation was found between CCL/T0 and CCL/T12, GT/T0 and AC-GM/T12, BT/T0 and GT/T12. A few negative moderate correlations were PD/T0 and CCL/T12, PD/T0 and PH/T0, PD/T0 and BT/T12. CONCLUSIONS: ACL procedure was effective. Although some rebound occurred, that was not clinically important. PD tended to reestablish its original length, partially due to a migration of GM during the healing period. Besides, a thickening of supracrestal soft tissues was observed. CLINICAL RELEVANCE: The present study centers on the factors influencing the stability of periodontal tissues after esthetic crown lengthening, underscoring the procedure's influence on esthetics and biology and the need for careful treatment planning.

High glucose impairs human periodontal ligament cells migration through lowered microRNAs 221 and 222.

OBJECTIVE: To investigate the effects of miR-221 and miR-222 and high glucose on human periodontal ligament (PL) cells morphology, cytoskeleton, adhesion, and migration. BACKGROUND: Chronic hyperglycemia is common in uncontrolled diabetes mellitus (DM) and plays a central role in long-term DM complications, such as impaired periodontal healing. We have previously shown that high glucose increases apoptosis of human PL cells by inhibiting miR-221 and miR-222 and consequently augmenting their target caspase-3. However, other effects of miR-221/222 downregulation on PL cells are still unknown. METHODS: Cells from young humans' premolar teeth were cultured for 7 days under 5 or 30 mM glucose. Directional and spontaneous migration on fibronectin were studied using transwell and time-lapse assays, respectively. F-actin staining was employed to study cell morphology and the actin cytoskeleton. MiR-221 and miR-222 were inhibited using antagomiRs, and their expressions were evaluated by real-time RT-PCR. RESULTS: High glucose inhibited PL cells early adhesion, spreading, and migration on fibronectin. Cells exposed to high glucose showed reduced polarization, velocity, and directionality. They formed several simultaneous unstable and short-lived protrusions, suggesting impairment of adhesion maturation. MiR-221 and miR-222 inhibition also reduced migration, decreasing cell directionality but not significantly cell velocity. After miR-221 and miR-222 downregulation cells showed morphological resemblance with cells exposed to high glucose. CONCLUSION: High glucose impairs human PL cells migration potentially through a mechanism involving reduction of microRNA-221 and microRNA-222 expression. These effects may contribute to the impairment of periodontal healing, especially after surgery and during guided regeneration therapies.

The impact of traditional smokers versus electronic cigarette smokers on periodontal parameters in iraqi males / O impacto do uso de cigarros tradicionais versus uso de cigarros eletrônicos nos parâmetros periodontais em homens iraquianos

Objective: To compare the effects of vaping and cigarette smoking and indicate their impact on periodontal health. Material and Methods: A total of 90 subjects divided into three groups. Group I: 30 Traditional cigarettes smoker who have smoked up to 10 cigarettes, Group II: 30 electronic cigarettes subjects who have been using vape at least one year and never smoke, and Group III: 30 subjects who have no smoking history. Using a mirror and a periodontal probe, periodontal parameters (plaque index, gingival index, probing depth and clinical attachment loss) were used to evaluate periodontal health. Results: The findings showed that the periodontal parameters had a highly significant differences at P ≤ 0.01 between traditional and electronic smoking groups. While clinical attachment loss demonstrated non-significant difference P ≥ 0.05 in comparison between electronic cigarettes and the group who never smoke. Conclusion: The results of this study suggested that traditional cigarettes and electronic cigarettes both had unfavorable impact on periodontal health status, never the less quit smoking showed positive impacts on periodontal parameters (AU)

Objetivo: O objetivo foi comparar os efeitos do uso do cigarro eletrônico e do cigarro convencional, indicando seus impactos na saúde bucal. Material e Método: 90 indivíduos foram divididos igualmente em três grupos: Grupo I, usuários de cigarro convencional que fumaram até 10 cigarros por dia; Grupo II: usuários de cigarro eletrônico que utilizam este por pelo menos há 1 ano e não fumavam antes disso; Grupo III: usuários sem qualquer história de hábitos tabagistas. Utilizando um espelho bucal e uma sonda periodontal, parâmetros periodontais (índice de placa, índice gengival, profundidade de sondagem e perda de inserção clínica) foram coletados para avaliar a saúde periodontal. Resultados: As evidências mostraram que os parâmetros periodontais apresentaram diferença significativa (P ≤ 0.01) entre os grupos I e II. Conclusão: Os resultados deste estudo sugerem que tanto o uso de cigarro convencional como o de cigarro eletrônico possuem impactos desfavoráveis na saúde periodontal, e que a cessação do uso destes mostraram impactos positivos nos parâmetros periodontais(AU)

Lower incisor inclination and thickness of the alveolar process and mandibular symphysis in the development of gingival recession: A retrospective cohort study.

Introduction: Retrospective studies have found conflicting results regarding the relationship between lower incisor inclination and the development of gingival recession (GR) after orthodontic treatment. Objective: This study aimed to investigate the relationship between lower incisor inclination and alveolar process (AP) and mandibular symphysis (MS) thickness in the development of GR. Materials and Methods: Frontal intraoral photography and cephalometric radiography were conducted before (T0) and after (T1) orthodontic treatment of 62 subjects. The presence of GR was considered when the cementoenamel junction was visible in the lower incisor on the frontal intraoral photograph. The circumstances for improvement, stability, and worsening of the gingival situation were based on the reduction, maintenance, and increase in the number of lower incisors with GR before and after treatment. To measure the incisor-mandibular plane angle (IMPA) and the thickness of the AP and the MS were used the cephalometric radiographs. Results: Men had a significantly thicker MS than women at T0 and T1 (p < 0.0004). There was a significant reduction of approximately 10% in AP between T0 and T1 (p < 0.0001). Among subjects without GR at T0, 70.4% presented a stable gingival situation at T1. For subjects with 1 lower incisor with GR at T0, 50% showed improvement in the gingival situation at T1, 21.4% remained stable, and 28.6% experienced worsening. Sixteen lateral incisors presented a worsening gingival situation, representing an increase of 129% compared to the central incisors. Conclusion: No relationship was found between lower incisor inclination and the thickness of the AP and MS in the development of GR.

Porphyromonas gulae and PPAD antibodies are not related to citrullination in rheumatoid arthritis.

INTRODUCTION: Porphyromonas gulae have the enzyme PPAD, as P. gingivalis, which is responsible for citrullination related to the pathophysiology of rheumatoid arthritis and periodontitis; this implies the presence of two species of PPAD-producing bacteria in the mouth as well as the presence of citrullinated proteins. There are no previous reports or studies investigating an association between P. gulae PPAD in rheumatoid arthritis (RA). OBJECTIVE: To assess the presence of P. gulae and anti-citrullinated peptide antibodies of P. gulae PAD in patients with RA and their possible relationship with clinical activity markers. SUBJECTS AND METHODS: A total of 95 patients with RA and 95 controls were included. Erythrocyte sedimentation rate (ESR), C-reactive protein, anti-citrullinated protein antibodies (ACPAs) and rheumatoid factor (RF) were measured. Activity index-28 (DAS28) and SCDAI. The periodontal diagnosis was established. Presence of P. gulae and P. gingivalis. An ELISA was used to determine antibodies against citrullinated peptides of P. gulae PAD. RESULTS: A P. gulae frequency of 15.8% was observed in the RA group and 9.5% in the control group. Higher levels of ACPA were found in the P. gulae-positive patients of the RA group, finding no significant difference, but if in patients positive for P. gingivalis with statistical significance (p = 0.0001). The frequency of anti-VDK-cit and anti-LPQ-cit9 antibodies to PPAD of P. gulae was higher in the RA group than in the control group without significant difference. No relationship was found with the clinical variables despite the presence of P. gulae and anti-citrullinated peptide antibodies of P. gulae PPAD in patients with RA CONCLUSIONS: It was not possible to establish a connection with clinical variables in RA and P. gulae; as a result, the presence of P. gingivalis continues to contribute significantly to the increase in antibodies against citrullinated proteins/peptides from exogenous sources of citrullination in RA and periodontitis.

Solution NMR structure of cementum protein 1 derived peptide (CEMP1-p1) and its role in the mineralization process.

We report the characterization of the three-dimensional structure of the CEMP1-p1 peptide [MGTSSTDSQQAQHRRCSTSN: corresponding to residues 1-20 of the N-terminus of cementum protein 1 (CEMP1)]. This peptide imitates the capacity of CEMP1 to stimulate hydroxyapatite (HA) crystal nucleation and growth, and promotes the differentiation of periodontal ligament cells into a cementoblastic phenotype. Additionally, in experimental models of critical-sized calvarial defects in Wistar rats, CEMP1-p1 has shown osteogenic properties that enhanced the physiological deposition and maturation of newly formed bone. In this work, studies of CEMP1-p1 by circular dichroism (CD) and nuclear magnetic resonance (NMR) were performed in trifluoroethanol D2 (TFED2) and aqueous solution to determine the 3D structure of the peptide. Using the 3D model, experimental data from HA crystals formation and calcium fluorescence emission, we explain the biological mechanisms involved in CEMP1-p1 activity to promote calcium recruitment and its affinity to HA crystals. This information is valuable because it proposes, for the first time, a plausible molecular mechanism during the mineralization process, from a specific cementum protein-derived peptide.

Effect of mouthwashes on gingival healing after surgical procedures: A systematic review.

The aim of the present study was to perform a systematic review of the literature regarding the effect of different mouthwashes on gingival healing after oral surgery in adults. Searches were conducted in seven databases (PubMed/MEDLINE, Cochrane Library, Clinical Trials Registry, Embase, LILACS, Web of Science, and Google Scholar) for relevant randomized controlled trials (RCTs) published up to April 2022. The selection of studies, data extraction, and risk of bias appraisal were performed independently by two reviewers, and a third researcher was consulted to resolve disagreements. Data syntheses were presented narratively for the different criteria of gingival wound healing. Among 4502 articles retrieved from the databases, 13 studies met the eligibility criteria and were included in the present review. Chlorhexidine was the most frequent mouthwash studied (eight studies) and was used in different concentrations and combinations. Cetylpyridinium chloride, H2 Ocean Sea Salt, Commiphora molmol 0.5%, chlorhexidine 0.12%, and essential oils reported better healing than a negative control. However, the uncertain risk of bias in most RCTs included in this review precludes definitive conclusions. Well-designed RCTs are therefore still needed in this area.

Periodontal bacteria in the brain-Implication for Alzheimer's disease: A systematic review.

Periodontitis is a chronic non-communicable disease caused by a dysbiotic microbiota. Pathogens can spread to the bloodstream, colonize other tissues or organs, and favor the onset of other pathologies, such as Alzheimer's disease (AD). Pathogens could permanently or transiently colonize the brain and induce an immune response. Thus, we analyzed the evidence combining oral bacteria's detection in the brain, both in animals and humans affected with AD. This systematic review was carried out following the PRISMA guideline. Studies that detected oral bacteria at the brain level were selected. The search was carried out in the Medline, Latindex, SciELO, and Cochrane Library databases. SYRCLE tool and Newcastle-Ottawa Scale were used for the risk of bias assessment. 23 studies were selected according to the eligibility criteria. Infection with oral pathogens in animals was related to developing neuropathological characteristics of AD and bacteria detection in the brain. In patients with AD, oral bacteria were detected in brain tissues, and increased levels of pro-inflammatory cytokines were also detected. There is evidence of a microbiological susceptibility to develop AD when the most dysbiosis-associated oral bacteria are present. The presence of bacteria in the brain is related to AD's pathological characteristics, suggesting an etiological oral-brain axis.

Periodontitis severity relationship with metabolic syndrome: A systematic review with meta-analysis.

The objective of this study was to investigate the association between periodontitis severity and metabolic syndrome (MetS) through systematic review, registered in PROSPERO: CRD42021232120. Selected articles were independently chosen by three reviewers from six databases, including using article reference lists, up until March 2022. Eligible studies were observational, without language limitation, and in subjects aged at least 18 years. The methodological quality of selected studies was assessed using the Newcastle-Ottawa Scale. Random effects models calculated summary measurements (odds ratio-OR, 95% confidence interval, 95%CI). The I2 test evaluated the statistical heterogeneity of the data. Sensitivity, subgroup, and meta-regression analyses were performed. For the reliability of evidence, the Grading of Recommendations, Assessment, Development, and Evaluations tool was used. A total of 2133 records were identified, and 14 studies were included comprising 24,567 participants. The summary odds ratio showed a positive association between individuals with moderate (ORadjusted  = 1.26; 95%CI = 2.10-5.37; I2  = 45.85%), and severe periodontitis (ORadjusted  = 1.50; 95%CI:1.28-1.71; I2  = 56.46%), and MetS. Subgroup and meta-regression analyses showed that study effect size was influenced by year of publication, study design, and MetS diagnostic criteria, contributing to inter-study variability. The findings showed that moderate and severe levels of periodontitis are associated with MetS, suggesting a possible dose-response effect.

Gingivitis en el embarazo

Introducción: El embarazo es una época de cambios para las mujeres. Se producen cambios en todo el organismo debido al aumento de los niveles de la hormona progesterona. La encía es un tejido clave para la acción de las hormonas esteroideas, por tal motivo los cambios clínicos en los tejidos periodontales se identifican durante los periodos de fluctuación hormonal. Objetivo: Sistematizar aspectos sobre qué es la gingivitis en el embarazo, cuáles son sus causas y consecuencias, y cómo tratarla de forma segura para la madre y el bebé. Método: Se realizaron revisiones bibliográficas donde se pudo abordar e interpretar las manifestaciones de la enfermedad periodontal durante el embarazo. Fueron examinados 20 artículos científicos de revistas nacionales e internacionales tanto en español y portugués de los últimos 5 años (2018-2022); de los 20 artículos se excluyeron 5, ya que no coincidían con el tema investigado. Resultados: Los efectos de los estrógenos y la progesterona en el periodonto han sido objeto de atención por los investigadores a lo largo de los años. Por esta razón los tejidos periodontales de la mujer son más susceptibles a esta patología durante el embarazo debido al aumento gradual en el nivel plasmático de progesterona y estrógenos, lo cual conlleva a un acúmulo anormal de bacterias, lo que genera esta enfermedad conocida como gingivitis. Dicha entidad presenta una prevalencia que oscila entre el 35 al 100 %. Consideraciones finales: Si la gingivitis no es tratada durante los dos primeros trimestres las bacterias pueden migrar al torrente sanguíneo y fijarse en la placenta. El cuerpo, como mecanismo de defensa para salvar al bebé entra en trabajo de parto, lo que provoca un parto prematuro. Por este hecho es indispensable asistir a los controles odontológicos.

Introduction: Pregnancy is a time of change for women. Changes occur throughout the body due to increased levels of the hormone progesterone. The gingiva is a key tissue for the action of steroid hormones, for this reason clinical changes in periodontal tissues are identified during periods of hormonal fluctuation. Objective: To systematize aspects of what gingivitis in pregnancy is, what its causes and consequences are, and how to treat it safely for the mother and baby. Method: Bibliographic reviews were carried out where the manifestations of periodontal disease during pregnancy could be addressed and interpreted. 20 scientific articles from national and international journals in both Spanish and Portuguese from the last 5 years (2018-2022) were examined; Of the 20 articles, 5 were excluded, since they did not coincide with the topic investigated. Results: The effects of estrogen and progesterone on the periodontium have been the subject of attention by researchers over the years. For this reason, women's periodontal tissues are more susceptible to this pathology during pregnancy due to the gradual increase in the plasma level of progesterone and estrogen, which leads to an abnormal accumulation of bacteria, which generates this disease known as gingivitis. This entity has a prevalence that ranges between 35 to 100%. Final considerations: If gingivitis is not treated during the first two trimesters, bacteria can migrate into the bloodstream and settle in the placenta. The body, as a defense mechanism to save the baby, goes into labor, which causes premature birth. For this reason, it is essential to attend dental check-ups.

Introdução: A gravidez é um momento de mudanças para a mulher. Mudanças ocorrem em todo o corpo devido ao aumento dos níveis do hormônio progesterona. A gengiva é um tecido fundamental para a ação dos hormônios esteróides, por esta razão são identificadas alterações clínicas nos tecidos periodontais durante períodos de flutuação hormonal. Objetivo: Sistematizar aspectos do que é gengivite na gravidez, quais são suas causas e consequências e como tratá-la com segurança para a mãe e o bebê. Método: Foram realizadas revisões bibliográficas onde puderam ser abordadas e interpretadas as manifestações da doença periodontal durante a gravidez. Foram examinados 20 artigos científicos de revistas nacionais e internacionais em espanhol e português dos últimos 5 anos (2018-2022); Dos 20 artigos, 5 foram excluídos, por não coincidirem com o tema investigado. Resultados: Os efeitos do estrogênio e da progesterona sobre o periodonto têm sido objeto de atenção de pesquisadores ao longo dos anos. Por este motivo, os tecidos periodontais das mulheres são mais suscetíveis a esta patologia durante a gravidez devido ao aumento gradual do nível plasmático de progesterona e estrogênio, o que leva a um acúmulo anormal de bactérias, o que gera esta doença conhecida como gengivite. Esta entidade tem uma prevalência que varia entre 35 a 100%. Considerações finais: Se a gengivite não for tratada nos dois primeiros trimestres, as bactérias podem migrar para a corrente sanguínea e se instalar na placenta. O corpo, como mecanismo de defesa para salvar o bebê, entra em trabalho de parto, o que provoca o nascimento prematuro. Por esse motivo, é imprescindível a realização de exames odontológicos.

Avaliação do comportamento das fibras colágenas periodontais durante a progressão da periodontite experimental em ratos / Evaluation of the behaviour of periodontal collagen fibers during the progression of experimental periodontitis in rats

Introdução: A periodontite é uma doença infecto-inflamatória, resultante da disbiose microbiana e da resposta do hospedeiro, que leva à destruição dos tecidos de suporte dentário, inclusive das fibras colágenas periodontais, podendo culminar na perda do elemento dental. Objetivo: Avaliar o comportamento das fibras colágenas periodontais durante a progressão da periodontite experimental induzida em ratos. Material e método: Doze ratos Wistar foram distribuídos nos grupos: Controle (C), Periodontite Experimental 14-dias (PE-14d), Periodontite Experimental 21-dias (PE-21d) e Periodontite Experimental 42-dias (PE-42d). No dia 0, os animais do grupo C foram eutanasiados. Neste mesmo dia, os animais remanescentes foram submetidos à instalação de uma ligadura de algodão ao redor do primeiro molar inferior esquerdo para indução da periodontite experimental. Tais animais foram eutanasiados aos 14 (PE-14d), 21 (PE-21d) e 42 (PE-42d) dias após a instalação da ligadura. Executou-se o processamento histológico das hemimandíbulas e as secções foram submetidas à reação histoquímica pelo vermelho picro-sirius. A análise qualitativa descritiva foi realizada sob microscopia de luz polarizada, na região de furca dental, evidenciando as fibras do ligamento periodontal. Resultado: O grupo C exibiu feixes espessos e orientados de fibras colágenas maduras, condizentes com aspecto de normalidade. Os grupos com periodontite experimental exibiram desestruturação tecidual severa, com fibras colágenas imaturas e de menor espessura, sendo tais condições mais exacerbadas nos grupos PE-14d e PE-21d. Conclusão: As fases iniciais da periodontite apresentam caráter agudo e, portanto, resultam na rápida destruição dos tecidos periodontais de suporte, prejudicando potencialmente a fibrilogênese e a reestruturação do colágeno no ligamento periodontal.

Introduction: Periodontitis is an infectious-inflammatory disease resulting from microbial dysbiosis and host response that leads to the destruction of tooth support tissues, including periodontal collagen fibers, which may culminate in tooth loss. Objective: To evaluate the behavior of periodontal collagen fibers during the progression of induced experimental periodontitis in rats. Material and method: Twelve Wistar rats were distributed into groups: Control (C), 14-days Experimental Periodontitis (PE-14d), 21-days Experimental Periodontitis (PE-21d) and 42-days Experimental Periodontitis (PE-42d). At day 0, the animals of group C were euthanized. At the same day, the remaining animals were submitted to the installation of a cotton ligature around the lower left first molar for the induction of experimental periodontitis. The animals were euthanized at 14 (PE-14d), 21 (PE-21d) and 42 (PE-42d) days after the installation of ligature. Histological processing of the hemi-mandibles was performed and the sections underwent histochemical reaction using picro-sirius red. The descriptive qualitative analysis was performed under polarized light microscopy, in the dental furcation region, evidencing the fibers of the periodontal ligament. Result: Group C exhibited thick and oriented bundles of mature collagen fibers, consistent with a normal appearance. The groups with experimental periodontitis exhibited severe tissue disruption, with immature and thinner collagen fibers, with such conditions being more exacerbated in the PE-14d and PE-21d groups. Conclusion: The early stages of periodontitis present acute response, and therefore result in rapid destruction of periodontal support tissues and potentially impair fibrillogenesis and collagen restructuring in the periodontal ligament.

Biological Activity of Copaiba in Damage to the Alveolar Bone in a Model of Periodontitis Induced in Rats.

Several studies have investigated the effects of natural products in the treatment of diseases. Traditional Amazonian populations commonly use copaiba due to its well-known anti-inflammatory, antibacterial, and healing properties. In this study, we aimed to investigate the effects of systemic administration of copaiba oleoresin (Copaifera reticulata Ducke) on ligature-induced periodontitis in rats. To do so, 21 adult rats were divided into three groups (n = 7 each): a control group, ligature-induced periodontitis group, and ligature-induced periodontitis group treated with copaiba oleoresin (200 mg/kg/day). The ligature remained from day 0 to 14, and the copaiba oleoresin was administered via oral gavage during the last seven days. On day 14, the animals were euthanized, and mandibles were collected for histopathological evaluation and microcomputed tomography analysis. Our data showed that the administration of copaiba considerably reduced the inflammatory profile. Moreover, copaiba oleoresin limited alveolar bone loss, increased trabecular thickness and bone-to-tissue volume ratio, and decreased the number of trabeculae compared with those of the untreated experimental periodontitis group. Our findings provide pioneering evidence that supports the potential of copaiba oleoresin in reducing periodontitis-induced alveolar bone damage in rats.

Chronic exposure to lead acetate promotes changes in the alveolar bone of rats: microstructural and physical-chemical characterization.

There are a few data relating to the effects of lead (Pb) exposure on the alveolar bone, which has very distinct morphophysiological characteristics and is of great importance in the oral cavity. In this context, the aim of this study was to investigate the changes promoted after long-term exposure to Pb in the microstructure of the alveolar bone of rats. Twenty adult Wistar rats were exposed to 50 mg/kg/day of lead acetate for 55 days. These animals were euthanized and had their mandible removed. Each mandible was divided into hemimandibles, and the alveolar bone was used for bone lead quantification, crystallinity analysis, microstructure evaluation by the percentage of bone volume (BV/TV), number of trabeculae (Tb.N), thickness of the trabecular (Tb.Th), and trabecular space (Tb.Sp). Morphometric analysis of the exposed root area was also performed. Long-term exposure to Pb resulted in high levels of Pb in the alveolar bone but showed no changes in the organization of crystallinity. The microstructural analyses showed a reduction of BV/TV, Tb.Th, and Tb.N and increase of Tb.Sp parameters, resulting in an increase in the exposed root area and an alveolar bone loss in height. The findings of this study reveal the ability of Pb to alter the alveolar bone microstructure after long-term exposure to the metal, possibly due to changes in tissue homeostasis, contributing to the reduction of bone quality.

Do smokers have a different gingival crevicular fluid cytokine/chemokine profile than nonsmokers in clinically healthy periodontal sites? A systematic review and meta-analysis.

OBJECTIVES: Assessing the evidence and comparing the levels of cytokines in gingival crevicular fluid (GCF) of periodontal healthy sites of smokers and nonsmokers. MATERIALS AND METHODS: Seven databases were surveyed for observational studies up to April 8, 2021. Studies comparing cytokine levels on GCF in periodontally healthy sites of smokers vs. nonsmokers were included in the study. The risk of bias was evaluated using NIH (2014) tool. For meta-analyses, levels in GCF were analyzed, followed by evidence certainty assessment using the GRADE approach. RESULTS: Eighteen studies were included for qualitative evaluation, and eight were included in meta-analysis. Qualitatively, despite high heterogeneity and risk of bias observed among the studies, most of them presented no significant difference in the gingival crevicular cytokine fluid levels between groups. Regarding meta-analyses, interleukin-8 (IL-8) and superoxide dismutase (SOD) levels in GCF were analyzed. The significant difference was observed only in SOD levels, where heavy smokers had lower levels compared to nonsmokers (MD - 30.06 [- 40.17, - 19.96], p = 0.07, 95%CI), as well as light smokers had lower levels compared to nonsmokers (MD - 15.22 [- 16.05, - 14.39], p < 0.00001, 95%CI). CONCLUSION: No distinct GCF cytokine profiles were detected for smokers and non-smokers. However, despite the limitations observed in the included studies, lower levels of SOD were identified in smokers. CLINICAL RELEVANCE: Indicating a distinct GCF profile of cytokines in periodontal healthy smokers may help to understand the mechanism whereby smoking may affect the host response.

Epithelial rests of Malassez in experimental animals at different ages.

Epithelial rests of Malassez (ERMs) are fragments of Hertwig's sheath in the periodontal ligament. There is extensive knowledge of their role in the etiology ofpathological processes and current evidence links them to maintenance of periodontal homeostasis. The aim of this study was to assess the behavior of ERMs with relation to the changes in periodontal tissues during growth in an experimental model with Wistar rats. Mesiodistal sections were made of the first lower molars from Wistar rats aged 1 month (n=7), 3 months (n=7) and 5 months (n=6). Sections were stained with H&E to evaluate number of ERMs/ mm, size/area of ERMs (pm2), height of periodontal ligament (PL.h) (pm), area of cement in the furcation zone (C.Ar) (pm2) and bone area related to the ERM zone (BAr/TAr)(%). Posthoc Bonferroni and ANOVA were applied for statistical analysis of results. Number of ERMs/mm declined significantly with age (1m: 4.34±1.51, 3m: 1.48±0.89, 5m: 0.27± 0.50, p<0.05), and there was great variability in size. There was significant increase in C.Ar (1m: 3418.96 ± 905.88, 3m: 19365.76 ± 5500.52, 5m: 32182.76 ± 7114.51, p< 0.05) and interradicular (BAr/TAr) (1m: 25.26 ± 2.37, 3m: 44.70 ± 3.95, 5m: 46.81 ± 7.80, p< 0.05: 1 vs 3, 1 vs 5). There was significant decline in PLh at 5 months (1m: 141.42 ± 29.25, 3m: 162.06 ± 28.21, 5m: 124.72 ± 18.67, p< 0.05: 1 vs. 3, 3 vs. 5). The decline in number of ERMs as animal age increases may be related to the significant increase in C.Ar and reduction in PL.h. It remains to ascertain its relationship with the increase observed in BAr/ TAr. Further studies are needed to learn more about the role of ERMs and their relationship with periodontal tissues when confronted with different normal and pathological stimuli.

Los restos epiteliales de Malassez (ERMs) son fragmentos de la vaina de Hertwig, en el ligamento periodontal. Se conoce extensamente su rol en la etiología de procesos patológicos y actualmente las evidencias los vinculan al mantenimiento de la homeostasis periodontal. El objetivo del presente trabajo fue evaluar el comportamiento de los ERMs en relación a los cambios de los tejidos periodontales durante el crecimiento en un modelo experimental de ratas Wistar. Se obtuvieron cortes mesio-distales del 1er molar inferior de ratas Wistar de 1 mes (n=7), 3 meses (n=7) y 5 meses (n=6) de edad. En cortes coloreados con H&E, se evalúo: N° de ERMs/mm, tamaño/ área de ERMs (pm2), altura del ligamento periodontal (PL.h) (pm), área de cemento en la zona de furcación (C.Ar) (pm2) y área del hueso relacionado con la zona de los ERMs (BAr/TAr) (%). Los resultados se analizaron estadísticamente mediante ANOVA y Bonferroni post-hoc. El N° de ERMs/mm disminuyó significativamente con la edad (1m: 4.34±1.51, 3m: 1.48±0.89, 5m: 0.27± 0.50, p<0.05), observándose una gran variabilidad de tamaño. Se observó un aumento significativo del CAr (1m: 3418.96 ± 905.88, 3m: 19365.76 ± 5500.52, 5m: 32182.76 ± 7114.51, p< 0.05) y del (BAr/TAr). interradicular (1m: 25.26 ± 2.37, 3m: 44.70 ± 3.95, 5m: 46.81 ± 7.80, p< 0.05: 1 vs 3, 1 vs 5). Además, se halló una disminución significativa en PLh a los 5 meses (1m: 141.42 ± 29.25, 3m: 162.06 ± 28.21, 5m: 124.72 ± 18.67, p< 0.05: 1 vs 3, 3 vs 5). La disminución hallada del número de ERMs conforme aumenta la edad del animal podría vincularse con el aumento significativo del C.Ar y la reducción del PL.h. Resta por dilucidar su relación con el aumento de BAr/TAr. observado. Se requieren más estudios para profundizar sobre el rol de los ERMs y su relación con los tejidos periodontales ante distintos estímulos normales y patológicos.

Clinical and tomography evaluation of periodontal phenotypes of Brazilian dental students.

BACKGROUND: The periodontal phenotype (PP) plays an important role in the function, esthetics, and maintenance of periodontal health and has a great influence in periodontal, restorative, and dental implant therapies. AIM: The aim of this study was to conduct a clinical evaluation of the PP and its morphometric variations through the cone-beam computed tomography (CBCT), from dentistry students with periodontal health. MATERIALS AND METHODS: Sixty students were examined, and the clinical parameters of probing depth and width of keratinized tissue (WKT) in the upper anterior segment were accessed. The gingival thickness was evaluated as thick or thin, through the translucency of the periodontal probe through the marginal gingiva. By convenience sample, 13 students were selected to assess bone thickness and gingival thickness and biological width through the previous CBCT examination. RESULTS: The most prevalent PP, according to the classification by De Rouck et al., was the thick scalloped (55%), and using the classification of Kao and Pasquinelli, the thick PP was most common (73,3%). The thick PP in both the classifications was more prevalent in both genders and the WKT was significantly higher in the thick-flat scalloped PP. The bone thickness was always greater than the gingival thickness in CBCT examinations both in the measures 1 mm and 3 mm above the bone crest. The average of the biological width measurement was 2.02 mm. CONCLUSIONS: The thick PP was most prevalent in the sample studied, and the gingival thickness was always thinner than the bone thickness in the measures evaluated.

Cementocyte alterations associated with experimentally induced cellular cementum apposition in Hyp mice.

BACKGROUND: Cellular cementum, a mineralized tissue covering apical tooth roots, grows by apposition to maintain the tooth in its occlusal position. We hypothesized that resident cementocytes would show morphological changes in response to cementum apposition, possibly implicating a role in cementum biology. METHODS: Mandibular first molars were induced to super-erupt (EIA) by extraction of maxillary molars, promoting rapid new cementum formation. Tissue and cell responses were analyzed at 6 and/or 21 days post-procedure (dpp). RESULTS: High-resolution micro-computed tomography (micro-CT) and confocal laser scanning microscopy showed increased cellular cementum by 21 dpp. Transmission electron microscopy (TEM) revealed that cementocytes under EIA were 50% larger than control cells, supported by larger pore sizes detected by micro-CT. Cementocytes under EIA displayed ultrastructural changes consistent with increased activity, including increased cytoplasm and nuclear size. We applied EIA to Hyp mutant mice, where cementocytes have perilacunar hypomineralization defects, to test cell and tissue responses in an altered mechanoresponsive milieu. Hyp and WT molars displayed similar super-eruption, with Hyp molars exhibiting 28% increased cellular cementum area versus 22% in WT mice at 21 dpp. Compared to control, Hyp cementocytes featured well-defined, disperse euchromatin and a thick layer of peripherally condensed heterochromatin in nuclei, indicating cellular activity. Immunohistochemistry (IHC) for cementum markers revealed intense dentin matrix protein-1 expression and abnormal osteopontin deposition in Hyp mice. Both WT and Hyp cementocytes expressed gap junction protein, connexin 43. CONCLUSION: This study provides new insights into the EIA model and cementocyte activity in association with new cementum formation.