Effects of low-dose aspirin on the osseointegration process in rats.

BACKGROUND: Several drugs are capable of promoting changes in bone metabolism. The aim of this study was to evaluate the effect of long-term low-dose aspirin (LDA) therapy on implant osseointegration. METHODS: Male Wistar rats were divided into 4 groups (n = 8/group) according to oral gavage solution received prior (42 days) to the implant surgery on the tibia. The control group was treated with saline solution for 7 (CG-7) and 28 (CG-28) days. The use of low-dose aspirin was performed in AG groups (6.75 mg/kg of aspirin) for 7 (AG-7) and 28 (AG-28) days. After experimental periods, histomorphometric evaluation of bone-to-implant contact (BIC) and the bone area between threads (BABT) was performed. RESULTS: Reduced BIC values were detected in AG-7 (62.8% ± 17.1) group compared to AG-28 (91.9% ± 5.4), CG-7 (82.7% ± 15.2), and CG-28 (89.9% ± 9.7). BABT evaluation revealed lower values in AG-7 (70.9% ± 15.2) compared to AG-28 (95.4% ± 3.7) and CG-28 (87.1% ± 10.2) groups. CONCLUSIONS: The treatment with low doses of aspirin promoted a discrete inhibitory effect in the early stages (7 days) of repair after implant placement, specifically in the bone deposition. However, these effects were not detected in the late stages (28 days), considering BIC and BABT parameters.

Efficacy of antimicrobial photodynamic therapy (aPDT) for nonsurgical treatment of periodontal disease: a systematic review.

Although the standard treatment for periodontal disease is based on scaling and root planing (SRP), the use of antimicrobial photodynamic therapy (aPDT) has been studied as a complement to obtain better clinical results. The purpose of this study was to evaluate the effect of aPDT as adjuncts to SRP, compared with SRP alone, on clinical parameters of chronic periodontal patients. Only randomized controlled trials with at least 3-month follow-ups, of SRP alone and in association with aPDT, were included. The MEDLINE (PubMed), Google Scholar, and LILACS databases were searched for articles published up to July 2020. Random-effects meta-analyses were conducted for clinical attachment level (CAL) and probing pocket depth (PPD) change after treatment. Of 141 potentially relevant papers, 22 were included. The association between SRP and aPDT promoted a significant CAL gain and PPD reduction. Periodontal treatment was partially improved by aPDT, and a favorable effect of indocyanine green-mediated aPDT was observed, and high concentrations of phenothiazine chloride presented clinical improvement as well.

Effect of magnification on root coverage surgery: a systematic review

Root coverage surgery can be performed in patients with gingival recession to cover the exposed root aiming to control hypersensitivity and promotes better aesthetic. Optical magnification has been proposed as a refinement in this surgical technique to increase root coverage. This approach may lead to enhanced soft tissue stability, less post-operative discomfort, better predictability and esthetic appearance. Aim: This systematic review aimed to evaluate the effectiveness of magnification on root coverage surgery when compared to procedures performed without magnification. Methods: Randomized controlled trials with a follow-up of at least 6 months that compared surgeries for root coverage performed under optic magnification versus conventional (macro) root coverage surgery were screened. The primary outcome was mean root coverage (mm) (MRC) and secondary outcomes were percentage of root coverage (PRC) and complete root coverage (CRC). Results: Of 569 papers relevant to this review, seven were included. Meta-analysis showed that the use of magnification may favor greater PRC (7.38%, 95% CI 3.66-11.09). Conclusion: Magnification can increase PRC in root coverage surgeries. More randomized trials with the use of magnification may be necessary to verify if this benefit is clinically relevant, in order to justify the use of this device

Effects of Selective Versus Non-Selective COX-2 Inhibition on Experimental Periodontitis.

In the present study we compared the effects of the selective COX-2 inhibitor etoricoxib with those of the classical non-selective NSAID diclofenac on the inflammatory process and alveolar bone loss in an experimental model of periodontitis in rats. Ninety male Holtzman rats (250 g) were randomly sorted into four experimental groups: Sham+CMC and Ligature+CMC (control) groups which received 0.5% carboxymethylcellulose sodium (CMC) solution; Ligature+Diclofenac and Ligature+Etoricoxib groups which received Potassium Diclofenac and Etoricoxib, respectively, suspended in 0.5% CMC (10 mg/kg/day). At 7, 14 and 21 days after placing ligatures in the cervical region of both the lower right and left first molars, the animals were euthanized. At the end of each period, the mandibles were collected for radiographic examination of alveolar bone loss. In addition, alveolar bone and periodontal ligament tissue samples were collected for COX-2 expression analysis and gingival tissues were collected for measurement of PGE2 contents. Animals with ligature-induced periodontal disease showed significant increased COX-2 gene expression at days 7, 14 and 21 (p<0.05) on alveolar bone and periodontal ligament. However, both treatments resulted in significantly reduced alveolar bone loss when compared to the untreated Ligature group (p<0.05), with no statistical difference between Etoricoxib and Diclofenac Potassium groups. This study shows that both drugs were able to reduce alveolar bone loss after periodontal disease induction.

Avaliação do efeito do antagonismo do receptor de leucotrienos na modulação da periodontite experimental em ratos / Cysteinyl leukotriene receptor antagonism modulates experimental periodontitis in rats

Na doença periodontal, quando ativada a resposta imunoinflamatória do hospedeiro, os leucotrienos (LTs) participam do processo de lesão tecidual pela quimiotaxia de leucócitos e ativação osteoclástica. O uso de antagonista do receptor de LTs está relacionado com a expressão de moléculas pró-inflamatórias e osteoclastogênese. No entanto, suas implicações na progressão da DP ainda não foram estudadas. Sendo assim, o trabalho teve como objetivo avaliar o efeito de antagonista do receptor de LTs (Montelucaste - MT) na modulação da periodontite experimental induzida pelo método da ligadura em ratos. Ratos Wistar machos (6-8 semanas, 200-250 gramas) foram divididos (12 animais/ grupo) nos seguintes grupos experimentais: Sham - sem ligadura/ sem tratamento (carboximetilcelulose - CMC 0,5%, via gavagem); Periodontite - com ligadura/ sem tratamento; MT 10 - com ligadura/ com tratamento (Montelucaste 10 mg/kg/dia, via gavagem); MT 30 - com ligadura/ com tratamento (Montelucaste 30 mg/kg/dia, via gavagem). Após período experimental (7, 14 e 21 dias) os animais foram submetidos à eutanásia e as hemimandíbulas retiradas para realização da análise de perda óssea alveolar (POA) macroscópica, análise histológica (H&E - histopatológico; picrosirius - colágeno), ELISA (LTB4), atividade de mieloperoxidase (MPO), avaliação de marcadores do estresse oxidativo (glutationa, expressão de proteínas carboniladas e proteínas modificadas por 4HNE) e expressão gênica de receptor do ativador de fator nuclear kappa B (RANK), ligante de RANK (RANKL), osteoprotegerina (OPG), fator de transcrição relacionado ao runt 2 (RUNX2), Colágeno tipo I, receptor de LT 1 (BLT1), receptor 1 de cisteinil-leucotrieno (CisLTR1), LTA4 hidrolase (LTA4H) e LTC4 sintase (LTC4S) (ANOVA, pós teste Sidak, p<0,05). O grupo Periodontite apresentou maior POA em comparação ao grupo Sham nos três períodos experimentais avaliados (p<0,05). MT passou a ser efetivo na redução da POA a partir do 14º dia (p<0,05). Ao analisar a degradação de colágeno, no 21º dia os grupos Periodontite e MT apresentaram maior perda em comparação ao grupo Sham (p<0,05). Não foram encontradas diferenças estatísticas quanto à expressão de LTB4 pelo teste ELISA (p>0,05), bem como na avaliação de marcadores de estresse oxidativo, independente do teste realizado (p>0,05). Em relação à MPO, o grupo Periodontite apresentou valores estatisticamente maiores em comparação ao grupo Sham nos três períodos experimentais (p<0,05). Nos períodos de 7 e 14 dias (30 mg/kg) o grupo MT promoveu diminuição da infiltração granulocítica em comparação ao grupo Periodontite (p<0,05), sem diferença em relação ao grupo Sham (p>0,05). Observou-se que a expressão de colágeno tipo 1 não apresentou diferença significante entre os grupos (p>0,05), e que o grupo MT 30 apresentou maior expressão de RUNX2 em comparação aos grupos Sham e Periodontite (p<0,05). No grupo MT 30 houve uma redução significante da expressão de LTA4H, BLT1 e LTC4S (p<0,05). A expressão de CysLTR1 não diferiu entre os grupos (p>0,05). Conclui-se que o uso de antagonista de receptor de LTs foi efetivo na redução do infiltrado granulocítico e da POA, com aumento de RUNX2.

Agreement, correlation, and kinetics of the alveolar bone-loss measurement methodologies in a ligature-induced periodontitis animal model.

Periodontal research involves the use of animal models to better understand the biological processes of periodontal diseases and the potential of new or existing therapies. Currently, ligature-induced periodontitis in rats is the main model used in periodontal research, in this model, alveolar bone loss (ABL) is the main parameter evaluated by radiographic, morphometric, and histological techniques. Interestingly, although these methodologies are widely used, it is not totally clarified neither the kinetics of ABL over the induction time nor the agreement degree (repeatability and reproducibility) of these techniques. OBJECTIVE: To characterize ABL kinetics at 0, 3, 7, 15, 30, and 60 days after ABL induction by ligature and to evaluate the intra- (repeatability) and inter-examiner (reproducibility) agreement and the correlation among the radiographic, morphometric, and histological methodologies. MATERIAL AND METHODS: 60 male Wistar rats with induced ABL were randomly divided into 6 experimental groups (n = 10 animals/group). After 0, 3, 7, 15, 30, and 60 days, the animals were euthanized and their hemimandibles were removed for ABL determination using radiographic, morphometric and histological techniques. RESULTS: Radiographic and morphometric/linear techniques allowed the detection of statistically significant ABL on the third day, while histological and morphometric/area techniques could only detect ABL after the seventh day (ANOVA/Tukey, p<0.05). After the fifteenth day, except for histological analysis, the ABL was stabilized. Concerning the agreement of the methodologies, Bland Altman's test (intra and inter-examiner evaluations) showed no difference among the measurements (p>0.05). In addition, high correlations (Pearson's test, r2>0.9, p<0.05) were observed. CONCLUSION: The results indicated that the minimum time for ABL induction could vary from 3 to 7 days, according to the chosen analysis methodology. Agreement and correlation data support the comparison of results between studies with same induction time.

Agreement, correlation, and kinetics of the alveolar bone-loss measurement methodologies in a ligature-induced periodontitis animal model

Abstract Periodontal research involves the use of animal models to better understand the biological processes of periodontal diseases and the potential of new or existing therapies. Currently, ligature-induced periodontitis in rats is the main model used in periodontal research, in this model, alveolar bone loss (ABL) is the main parameter evaluated by radiographic, morphometric, and histological techniques. Interestingly, although these methodologies are widely used, it is not totally clarified neither the kinetics of ABL over the induction time nor the agreement degree (repeatability and reproducibility) of these techniques. Objective: To characterize ABL kinetics at 0, 3, 7, 15, 30, and 60 days after ABL induction by ligature and to evaluate the intra- (repeatability) and inter-examiner (reproducibility) agreement and the correlation among the radiographic, morphometric, and histological methodologies. Material and Methods: 60 male Wistar rats with induced ABL were randomly divided into 6 experimental groups (n = 10 animals/group). After 0, 3, 7, 15, 30, and 60 days, the animals were euthanized and their hemimandibles were removed for ABL determination using radiographic, morphometric and histological techniques. Results: Radiographic and morphometric/linear techniques allowed the detection of statistically significant ABL on the third day, while histological and morphometric/area techniques could only detect ABL after the seventh day (ANOVA/Tukey, p<0.05). After the fifteenth day, except for histological analysis, the ABL was stabilized. Concerning the agreement of the methodologies, Bland Altman's test (intra and inter-examiner evaluations) showed no difference among the measurements (p>0.05). In addition, high correlations (Pearson's test, r2>0.9, p<0.05) were observed. Conclusion: The results indicated that the minimum time for ABL induction could vary from 3 to 7 days, according to the chosen analysis methodology. Agreement and correlation data support the comparison of results between studies with same induction time.

Anterosuperior rehabilitation with metal-free fixed prosthesis based on zirconia.

The loss of upper front dental elements causes functional and psychosocial problems to the affected individuals. In this case report, the treatment planning considered hard and soft tissue loss for a complex fixed partial denture (FPD) rehabilitation. The six-element, all-ceramic FPD was manufactured using a computer-aided design/computer-aided manufacturing system with zirconia framework, veneered with leucite-reinforced ceramic. Ceramic artificial gum was also produced to guarantee tooth-facial proportions as well as lip support, promoting both esthetics and phonetics. The material's mechanical properties allowed for the coupling of the esthetic and mechanical requirements, proving an alternative to the well-established metal-ceramic technology, optimizing biomimetic. One of the endodontic-treated abutment teeth required a radicular retainer with cast metal post, but because of the opacity of zirconia, the esthetics of the prosthesis was not compromised. The low silica content of high resistance ceramics such as zirconia hampers the adhesive cementation, with numerous studies advocating for different cementation protocols, with no clear scientific consensus so far. In the present case, the internal surface of the FPD was initially blasted with aluminum oxide, followed by the application of a universal adhesive system containing 10-methacryloyloxydecyl dihydrogen phosphate. Finally, cementation to the dental structure was conducted with dual-cure self-adhesive resin cement.

Moduladores da resposta do hospedeiro como adjuvantes no tratamento da doença periodontal / Modulators of the host response as adjuvants in the treatment of periodontal disease

Durante anos, o tratamento periodontal esteve voltado apenas para remoção do agente etiológico principal. No entanto, visto que o sistema imunoinflamatório do hospedeiro (patogênese da doença periodontal) é o principal responsável por promover a destruição dos tecidos periodontais, o uso de agentes que modulem essa resposta foi introduzido com o objetivo de melhores resultados no controle da doença. Dentre os Moduladores da Resposta do Hospedeiro (MRH), destacam-se a doxiciclina em dose subantimicrobiana, os anti-inflamatórios não esteroidais, bifosfonatos, agentes inibidores de citocinas, os moduladores da síntese de óxido nítrico e as lipoxinas. Desta forma, diante da grande importância que os MRH podem ter no controle da doença periodontal, o objetivo desta revisão é abordar diversas características e peculiaridades dos principais MRH adjuvantes no tratamento da doença periodontal, a fim de viabilizar seu uso na prática clínica (AU)

For a long time, periodontal treatment was only focused on removal of the main etiologic agent. However, since the host immunoinflammatory system (pathogenesis of periodontal disease) is the main responsible for promoting the destruction of periodontal tissues, the use of agents that modifies its response was introduced to obtain better results on disease control. Among the modulators of the host response (MHR), stand out subantimicrobial dose doxycycline, non-steroidal anti-inflammatory drugs, bisphosphonates, cytokine inhibitors, nitric oxide synthesis modulators and lipoxins. Thus, in view of the great importance that MHR may have on control of periodontal disease, the purpose of this review is to address several characteristics and peculiarities of the main adjuvant MHRs to treat periodontal disease, in order to make than feasible to use in clinical practice. (AU)

Gastric and renal effects of COX-2 selective and non-selective NSAIDs in rats receiving low-dose aspirin therapy.

The consumption of low-dose aspirin (LDA) to prevent cardiovascular disease continues to increase worldwide. Consequently, the number of chronic LDA users seeking dental procedures that require complementary acute anti-inflammatory medication has also grown. Considering the lack of literature evaluating this interaction, we analyzed the gastric and renal effects caused by a selective COX-2 inhibitor (etoricoxib) and a non-selective COX-2 inhibitor (ibuprofen) nonsteroidal anti-inflammatory drug (NSAID) in rats receiving chronic LDA therapy. Male Wistar rats were divided into six experimental groups (carboxymethylcellulose (CMC) - vehicle; LDA; LDA + ibuprofen; ibuprofen; LDA + etoricoxib; and etoricoxib) and submitted to long-term LDA therapy with a subsequent NSAID administration for three days by gavage. After the experimental period, we analyzed gastric and renal tissues and quantified serum creatinine levels. The concomitant use of LDA with either NSAID induced the highest levels of gastric damage when compared to the CMC group (F = 20.26, p < 0.05). Treatment with either LDA or etoricoxib alone was not associated with gastric damage. No significant damage was observed on kidney morphology and function (F = 0.5418, p > 0.05). These results suggest that even the acute use of an NSAID (regardless of COX-2 selectivity) can induce gastric damage when combined with the long-term use of low-dose aspirin in an animal model. Additional studies, including clinical assessments, are thus needed to clarify this interaction, and clinicians should be careful of prescribing NSAIDs to patients using LDA.

Gastric and renal effects of COX-2 selective and non-selective NSAIDs in rats receiving low-dose aspirin therapy

Abstract The consumption of low-dose aspirin (LDA) to prevent cardiovascular disease continues to increase worldwide. Consequently, the number of chronic LDA users seeking dental procedures that require complementary acute anti-inflammatory medication has also grown. Considering the lack of literature evaluating this interaction, we analyzed the gastric and renal effects caused by a selective COX-2 inhibitor (etoricoxib) and a non-selective COX-2 inhibitor (ibuprofen) nonsteroidal anti-inflammatory drug (NSAID) in rats receiving chronic LDA therapy. Male Wistar rats were divided into six experimental groups (carboxymethylcellulose (CMC) - vehicle; LDA; LDA + ibuprofen; ibuprofen; LDA + etoricoxib; and etoricoxib) and submitted to long-term LDA therapy with a subsequent NSAID administration for three days by gavage. After the experimental period, we analyzed gastric and renal tissues and quantified serum creatinine levels. The concomitant use of LDA with either NSAID induced the highest levels of gastric damage when compared to the CMC group (F = 20.26, p < 0.05). Treatment with either LDA or etoricoxib alone was not associated with gastric damage. No significant damage was observed on kidney morphology and function (F = 0.5418, p > 0.05). These results suggest that even the acute use of an NSAID (regardless of COX-2 selectivity) can induce gastric damage when combined with the long-term use of low-dose aspirin in an animal model. Additional studies, including clinical assessments, are thus needed to clarify this interaction, and clinicians should be careful of prescribing NSAIDs to patients using LDA.

Influência de diferentes tipos de máquinas de ensaio e da termociclagem na resistência adesiva ao cisalhamento e no índice de adesivo remanescente / Influence of different types of mechanical testing and thermocycling on shear bond strength and the adhesive remnant index

Este estudo comparou duas diferentes máquinas de ensaio mecânico (Shimadzu e Kratos), com ou sem a realização da termociclagem, na leitura da resistência adesiva ao cisalhamento (RAC) e do índice de adesivo remanescente (IAR) após a descolagem de bráquetes metálicos colados com resina Transbond XT. Foram utilizados 60 pré-molares humanos, nos quais foram colados bráquetes metálicos, divididos aleatoriamente em dois grupos: Grupo I – com termociclagem (500 ciclos) entre 5º e 55ºC e Grupo II – sem termociclagem. Estes grupos foram subdivididos em quatro subgrupos (n=15). Foi realizado o teste mecânico de cisalhamento com ambas as máquinas: subgrupos I A (Shimadzu) e I B (Kratos) e subgrupos II A (Shimadzu) e II B (Kratos). As amostras foram submetidas aos ensaios mecânicos de cisalhamento com velocidade de carga de 0,5 mm/min. Os resultados da RAC foram submetidos ao teste de normalidade de D’Agostino & Pearson, ANOVA - 1 Critério (a = 0,05), pós-teste de Tukey e os dados do IAR ao teste de Kruskal-Wallis (a = 0,05). Não foram encontradas diferenças estatisticamente significativas entre os subgrupos. Conclui-se que a utilização de diferentes tipos de máquinas de ensaio, com ou sem termociclagem, não apresentam diferenças estatísticas na leitura da resistência ao cisalhamento ou do índice de adesivo remanescente...

This study has compared two different mechanical testing machine (Shimadzu and Kratos), with or without performing of thermocycling, the reading of the adhesive shear strength (RAC) and the adhesive remnant index (ARI), after debonding of metal brackets bonded with Transbond XT resin. Metal brackets were bonded on sixty human premolars that were then randomly divided into two groups: Group I - with thermocycling (500 cycles) between 5 and 55ºC and Group II - without thermocycling. These groups were divided into four subgroups (n = 15). Test was performed with both mechanical shearing machines: subgroups I A (Shimadzu) and I B (Kratos) and subgroups II A (Shimadzu) and II B (Kratos). Samples were submitted to shear bond strength (SBS) testing with a crosshead speed of 0.5 mm/min. The results of the SBS were tested for normality D’Agostino & Pearson, test 1 way ANOVA (a = 0.05), Tukey post-test. Data from the ARI were submitted to the Kruskal-Wallis test (a = 0.05). There was no statistically significant difference between subgroups. There was no statistically significant difference between subgroups. It was concluded that the use of different types of test machines, with or without thermocycling did not show statistical differences in reading shear bond strength or adhesive remnant index...