Inhibitory effects of allicin effective component DATS on Enterococcus faecalis bofilm:An in vitro Study / 实用口腔医学杂志

Objective:To investigate the antibacterial efficacy of allicin effective component,dially trisulfide(DATS),on the biofilms of Enterococcus faecalis(E.faecalis)in vitro.Methods:60 healthy single root canal permanent teeth were selected.After cleaning and autoclaving,15 teeth without infection were used in the negative control group,45 teeth were contaminated by E.faecalis and incubated for 28 days as the infection models and devided into 3 groups(n=15)as below:DATS group,Calcium hydroxide group and positive(without antibacteria treatment)control group.The minial inhibition concentration(MIC)and minial bactericidal concentrition(MBC)of DATS on E.feacalis were studied with doubling diluting method.At the day 1,2 and 7 of the exprement,the 4 mg of root canal in-ner dentin powder,5 specimens of each group were sespectively transfered into sterile bottle containing 2 mL BHI broth and cultured at 37 ℃ 5％CO2 for 72 h,the turbitity of the upper layer of liquid of the culture was measured.Results:MIC and MBC(μg/mL)of DATS to E.feacalis was 2 560 and 5 120 repsectively.At the first day,turbidity in the DATS group was the lowest(P＜0.05).At the third day,turbidity showed no difference between DATS group and negative control group(P=0.454).At the 7th day,between calcium hydroxide and the negative control group,P＜0.05.Conclusion:DATS may suppress E.faecalis in the biofilm in vitro.

Research progress on small biomolecule formulations for chemical disinfection of root canals / 口腔疾病防治

@#Successful treatment of endodontic and periapical diseases requires the elimination of bacteria and microbial biofilms from root canals. Currently, the most preferred irrigation method involves the delivery of sodium hypochlorite via the combination of a syringe and ultrasonic activation. Calcium hydroxide is the main choice for intracanal medicament between endodontic appointments and treatment. However, conventional chemical disinfection of root canals is controversial due to drug permeability and drug resistance. New small biomolecule formulations with high penetrability and bioremediatory capacity, including antimicrobial peptides such as M33D and LL-37, antisense RNA ASwalR/ASvicR and nanoparticles such as silver nanoparticles, mesoporous calcium-silicate nanoparticles and chitosan nanoparticles, have effective antibacterial and antibiofilm properties for use in root canal systems and dentinal tubules, thereby promoting the healing of apical lesions. However, the in vivo drug stability, biosafety, and clinical efficacy of small biomolecule formulations need further investigation. Future research will still focus on the improvement and combination of traditional drugs, as new small molecule formulations and ideal disinfectant drugs need to be developed. In the present paper, we reviewed the development of new antibacterial agents and application of small biomolecule formulations for chemical disinfection of infected root canals.

Recent Advances in Root Canal Disinfection - A review

Chemical and mechanical root canal debridement are the primary methods used in conjuction with conventional endodontic therapy to remove all dead tissue, bacteria, and microbial byproducts from the root canal. Commonly used root canal disinfection with sodium hypochlorite, a powerful organic tissue dissolver with a broad spectrum of antibacterial properties is an excellent choice opted for dentists for disinfecting root canals. On the other hand, chelating agents such as EDTA is routinely used to remove the inorganic tissue components of the smear layer. The use of chelating agents in endodontic therapy is less effective in the apical third. While performing endodontic therapy, the dentist must ensure the direct contacts of irrigants with the whole root canal wall surfaces, especially in the narrower apical portions of the root canals. In the current article, the authors has presented a detailed review in context to the various irrigating solutions used during the biomechanical preparation, their actions and advantages and disadvantages.

An in vitro study on the clearance effect of oxygen-releasing photodynamic therapy on Enterococcus faecalis in the root canal / 口腔疾病防治

Objective@#To investigate the clearance effect of photodynamic therapy (PDT) with an oxygen-releasing photosensitizer methylene blue (MB) formula on Enterococcus faecalis in the root canal.@*Methods @# Groups were divided into the MB group and oxygen release MB group. Samples in the MB group were mixed with 50 μmol/L MB solution, and samples in the oxygen release MB group were mixed with 50 μmol/L MB in oxygen release emulsion. N-acetyl-L-tryptophan amide (NATA) and 1,3-diphenylisobenzofuran (DPBF) were used to detect the oxidative activity and singlet oxygen generation of different formulas of MB (MB group, oxygen-releasing MB group), and the oxygen-releasing capacity of the oxygen-releasing photosensitizer formula was analyzed. The single root canal anterior teeth were collected, and the Enterococcus faecalis root canal infection model of isolated teeth was constructed. The distribution of Enterococcus faecalis in the root canal was observed by scanning electron microscopy. The isolated teeth with Enterococcus faecalis root canal infection were divided into three groups: the conventional root canal therapy group, MB-PDT therapy group, and oxygen-releasing MB-PDT therapy group, with 10 teeth in each group. Bacterial samples in the root canals of each group were obtained, the number of colonies was analyzed(CFU/mL) after 24 h of in vitro culture, and the clearance rate of Enterococcus faecalis in the root canal by photodynamic therapy was evaluated. The remaining isolated teeth with Enterococcus faecalis root canal infection were divided into 3 groups, with 5 samples in each group. Bacterial samples at a depth of 1 000 μm in the dentin tubules of the upper root, middle root and lower root segment were obtained and cultured in vitro for 24 h for calculations. The number of colonies (CFU/mL) was analyzed, and the clearance rate of Enterococcus faecalis in the dentin tubules of different segments of the root canals in each group was analyzed. @*Results @#The oxidation activity and singlet oxygen generation capacity in the oxygen-releasing MB group were stronger than those in the MB group. Scanning electron microscope detection showed that Enterococcus faecalis was distributed in dentinal tubules, indicating that the model of root canal infection in vitro was successfully constructed. The clearance rate of Enterococcus faecalis in the oxygen-releasing MB-PDT therapy group was higher than that in the conventional therapy group and the MB-PDT therapy group (P<0.05). Oxygen-releasing PDT significantly improved the bactericidal effect in the lower dentinal tubules, and the clearance rate of Enterococcus faecalis was better than in the other two groups (P<0.05).@*Conclusion@#Photodynamic therapy with the oxygen-releasing photosensitizer MB can achieve a better root canal bactericidal effect and can significantly improve the clearance effect of Enterococcus faecalis in the deep dentin of the lower root segment.

Evaluation of sonic, ultrasonic, and laser irrigation activation systems to eliminate bacteria from the dentinal tubules of the root canal system

Abstract Aiming to kill bacteria in dentin tubules of infected dental pulp cavities, we evaluated the effects of sodium hypochlorite (NaOCl) solution agitated by different irrigation protocols, i.e., conventional needle irrigation (CNI), passive ultrasonic irrigation (PUI), the EDDY tip, and the neodymium-doped yttrium aluminum perovskite (Nd:YAP) laser. The EDDY achieved good antibacterial effects as passive ultrasonic irrigation in the coronal and middle thirds. Nd:YAP laser irradiation and PUI were effective in the apical third of the root canal. Objectives: To evaluate the ability of NaOCl agitated by high-frequency sonic irrigation-EDDY, PUI, and Nd:YAP laser-to kill bacteria in infected root canal walls and if the associated temperature increases at the root surface during application. Methodology: Infected root canal models were established, and roots were randomly divided into six groups: negative control, positive control, CNI, PUI, sonic agitation with EDDY, and Nd:YAP laser groups. After irrigation, the teeth were split and stained using the LIVE/DEAD BacLight Bacterial Viability Kit. Dead bacteria depth was evaluated by a confocal laser scanning microscopy and the temperature at the root surface was assessed using a thermal imaging camera during the irrigation process. Results: In the coronal and middle thirds of the root canal, PUI and EDDY had stronger antibacterial effects than CNI (p<0.05); in the apical third, the antibacterial effects of PUI and Nd:YAP laser-activated irrigation were better than CNI (p<0.05). The maximum change in temperature was significantly greater during continuous Nd:YAP laser application compared with the other methods, but intermittent irrigation helped lessening this trend. Conclusions: NaOCl agitated by EDDY tip and PUI exhibited a similar bacteria elimination effect in the coronal and middle root canal. Nd:YAP laser was effective in the apical third and intermittent irrigation reduced its thermal impact.

Eficacia del instrumento XP-endo Finisher y del sistema EndoActivator en la reducción/eliminación del biofilm bacteriano: un ensayo ex vivo / Ability of the XP-endo Finisher instrument and the EndoActivator system to reduce/eliminate of the bacterial biofilm: an ex vivo assay

Objetivos: Comparar ex vivo la eficacia del instrumento XP-endo Finisher y del sistema EndoActivator en la reducción/eliminación del biofilm microbiano en conductos radiculares infectados. Materiales y métodos: Se utilizaron 23 premolares inferiores humanos extraídos cuya longitud fue estandarizada en 17 mm. Todos los conductos se prepararon con el sistema WaveOne Gold Medium (#35.06). Los dientes se esterilizaron, se inocularon con Enterococcus faecalis y se separaron en dos grupos experimentales de 10 piezas cada uno. De los 3 dientes remanentes, 1 fue utilizado como control positivo y 2, como controles negativos. En el grupo 1, las soluciones irrigantes se agitaron con XP-endo Finisher. En el grupo 2, se utilizó EndoActivator. Se tomaron muestras antes de la contaminación, luego de esta y después de la agitación de los irrigantes mediante conos de papel estériles. La carga microbiana fue sembrada en agar sangre y los conos se cultivaron en caldo tripteína de soja. La remoción de la carga microbiana se determinó por la presencia o ausencia de turbiedad del medio. Las unidades formadoras de colonias (UFC) remanentes se cuantificaron y los resultados se categorizaron como R1 (≤10 UFC) o R2 (>10 UFC). Los datos fueron analizados mediante la prueba de Fisher. Resultados: No hubo diferencias significativas entre XP-endo Finisher y EndoActivator (P>0,05). El número de usos no influyó sobre la capacidad operativa de ambos instrumentos (AU)

Aim: To compare ex vivo the effectiveness of the XP-endo Finisher and the EndoActivator in biofilm reduction/ removal from infected root canals. Materials and methods: Twenty three extracted human single-rooted lower premolars were selected and standardised to 17 mm in length. All the canals were prepared with WaveOne Gold Medium reciprocating files (#35.06). The teeth were autoclaved and inoculated with Enterococcus faecalis. The infected teeth were then assigned to 2 experimental groups of 10 teeth each according to the final irrigation/agitation protocol. Of the three remaining teeth, one was used as a positive control, and the other two were used as negative controls. In Group 1 the irrigating solutions were agitated with XP-endo Finisher while in Group 2 the EndoActivator was used. All root canals were sampled before and after contamination, and again after irrigant agitation with sterile paper points. The microbial load was spread on blood agar plates and the paper points were cultured in sterile trypticase soy broth. The removal of the microbial load was determined by visual observation of the turbidity of the media and by quantification of the number of colony-forming units (UFC). The results were categorized as R1 (≤10 UFC) or R2 (>10 UFC). Data were analysed by the Fisher's exact test at P<0.05. Results: No significant differences was found between XP-endo Finisher and EndoActivator (P>0.05) regarding their effectiveness in the reduction/removal of the microbial biofilm. The number of uses of both instruments did not affect their operative performance (AU) Conclusion: XPF and EA were both equally effective for microbial biofilm reduction/removal from ex vivo infected root canals (AU)

Research progress on the effect of new disinfection methods on the clearance of Enterococcus faecalis in the root canal / 口腔疾病防治

@#Enterococcus faecalis has been confirmed to be closely related to dental pulp and periapical disease in recent years. Enterococcus faecalis is one of the important bacteria causing persistent or secondary root canal infection and root canal treatment failure. Traditional root canal disinfection drugs such as sodium hypochlorite, chlorhexidine and calcium hydroxide can not completely remove Enterococcus faecalis in the root canal because of the concentration limitation of the drug and the complexity of the root canal system. Therefore, how to effectively resist the Enterococcus faecalis infection in the root canal has become one of the important research directions in the treatment of periodontal pulp periapical disease. In recent years, some new antimicrobial agents and disinfection methods have emerged due to the drug resistance and pathogenicity of Enterococcus faecalis, such as laser, photodynamic, ultrasonic irrigation and ozone therapy. Their combination with traditional root canal irrigation drugs can significantly enhance the ability of traditional drugs to remove Enterococcus faecalis in the root canal. In addition, the emergence of new disinfection methods such as chlorine dioxide, nano-magnesia, superoxidized water and N-acetylcysteine have been shown to have a unique killing effect on Enterococcus faecalis in root canals. At present, most of the new disinfection methods described above are in the in vitro experimental stage, and their stimulation and damage to normal tissue still lack relevant clinical data support; thus, these outcomes need to be further studied.

Advances in the application of photodynamic therapy to root canal disinfection / 口腔疾病防治

@#In recent years, many researchers have devoted themselves to the application of photodynamic therapy (PDT) in root canal disinfection, as conventional root canal disinfection methods have failed to achieve the optimal effect. Some clinicians have also applied PDT to root canal disinfection. PDT is expected to have a better effect than traditional root canal disinfection. This paper reviews the research progress on the mechanism, effect, influencing factors and limitations of PDT in root canal disinfection. Current research suggests that differences in the type and status of the bacteria, photosensitizers, light sources, operating environment and methods all affect the efficacy of root canal disinfection of PDT. Most of the research into PDT for root canal disinfection finds that it is effective, nontoxic, advantageous to dental pulp regeneration and comfortable for the patient, as well as lacking an excitant; however, its bactericidal effect is inferior to that of sodium hypochlorite. At present, it cannot replace traditional chemical washing but is a promising auxiliary method. The design of the photosensitizer, the energy dose of the light source and the optimal irradiation time need to be determined by further experiments, and more clinical verification is needed before its application in root canal therapy.

Evaluation of antibacterial effect and short-term clinical effect of new triple antibiotic paste against Enterococcus faecalis for root canal retreatment / 第二军医大学学报

Objective: To compare the antibacterial effect and short-term clinical effect of new triple antibiotic paste (ornidazole, ciprofloxacin and minocycline) used alone and in combination with calcium hydroxide paste against Enterococcus faecalis in root canal retreatment. Methods: A total of 149 single rooted teeth with failed endodontic treatment were selected in the present study. The samples were randomly divided into 5 groups: calcium hydroxide paste group (CH group), triple antibiotic paste (metronidazole, ciprofloxacin and minocycline) group (TAP group), new triple antibiotic paste group (NTAP group), the combination group of calcium hydroxide paste and new triple antibiotic paste (CH+NTAP group), and camphor phenol group (CP group). After removal of the root-flling material, the quantities of Enterococcus faecalis in the root canals were determined before and after root canal preparation and 7 d after root dressing. The short-term clinical effects were evaluated 7 d after root dressing in each group. Results: After root canal preparation and root dressing of 7 d, the quantities of Enterococcus faecalis in root canals in each group were significantly decreased versus before root canal preparation (all P0.05). Conclusion: Calcium hydroxide paste and triple antibiotic paste alone or in combination have better antibacterial effect for root canal disinfection against Enterococcus faecalis in root canal retreatment. They also have better short-term clinical effect, especially the new triple antibiotic paste, which can be considered as an effective alternative intracanal medicament and is worthy of clinical application.

Killing activity of nonequilibrium plasma against young and old Enterococcus faecalis biofilms with long-term exposure in infected root canals in vitro / 中华口腔医学杂志

Objective@#To evaluate the antimicrobial activity of nonequilibrium plasma against Enterococcus faecalis (Ef) biofilms in vitro and to obtain novel evidence of root canal disinfection with nonequilibrium plasma.@*Methods@#Sterile cover slips and single-rooted canals were filled with Ef and incubated to form 1-week-old and 3-week-old biofilms, respectively. The infected samples were subjected to nonequilibrium plasma, 2% chlorhexidine digluconate (CHX) and saline for 3, 10 and 30 minutes, respectively. After treatment, the killing effectiveness of nonequilibrium plasma was analyzed by using laser scanning confocal microscopy (LSCM) and colony forming unit (CFU) counting.@*Results@#The 3-dimentional reconstruction LSCM images showed that about 48.3%-79.8% of 1-week-old Ef biofilm cells and 40.0%-67.4% of 3-week-old biofilm cells were killed by nonequilibrium plasma and 2% CHX compared to saline (P<0.05). The proportion of killing activity was lower after 3 minutes (40.0%-50.9% killing) than after 10 minutes (65.3%-77.8% killing) and 30 minutes (66.4%-79.8% killing) (P<0.05). And the killing of biofilm bacteria was fastest during the first 3 minutes (13.3%-17.0% killing per minute) and slow down greatly after 10 minutes. Remarkably more bacteria were killed in 1-week-old Ef biofilms (48.3%-79.8% killing) than in 3-week-old biofilms (P<0.05).@*Conclusions@#The nonequilibrium plasma killed more Ef biofilm cells in infected root canals showed promotional as an additional approach against bacterial biofilms during root canal disinfection.

Clinical observation of diode laser for the treatment of fistula chronic apical periodontitis in elderly people / 口腔疾病防治

Objective@#The present study investigated the role of a diode laser in the treatment of fistula chronic periapical periodontitis in elderly people. @*Methods @#A total of 114 cases of fistula chronic periapical periodontitis in the elderly were randomly divided into an experimental group and control group. In the experimental group, a diode laser was used to disinfect the root canal and the internal wall of the fistula after root canal preparation, and Vitapex paste was used in both groups for root canal disinfection. The control group was treated with conventional root canal therapy without laser treatment. The fistula healing rate was calculated, and root canal filling was performed in both groups two weeks later if the fistula was healed. A curative effect was observed at 3 months and 12 months.@*Results @#The fistula healing rate was 90.0% in the experimental group and 75.8% in the control group after 2 weeks. There was a significant difference between the two groups at 2 weeks (χ2 = 4.19, P < 0.05) but not at 3 months and 12 months (P > 0.05). @*Conclusion @#The use of a diode laser to disinfect the root canal and fistula of teeth in the elderly with fistula periapical periodontitis can significantly shorten the healing time of fistula.

Effect of Passive Ultrasonic Irrigation on Enterococcus faecalis from Root Canals: An Ex Vivo Study

Endodontic irrigation aims to clean and disinfect the root canal system. Passive ultrasonic irrigation (PUI) is based on the use of an ultrasound-activated instrument into the root canal filled with irrigant. The aim of this study was to evaluate, ex vivo, the effectiveness of PUI in eliminating Enterococcus faecalis from root canals. Seventy-five extracted human single-root teeth were used. After root canal preparation, specimens were inoculated with E. faecalis and incubated at 37 °C for 21 days. Specimens were distributed into five groups (n=15), according to the irrigation method: PUI + saline solution (PUI/SS); PUI + 1% NaOCl (PUI/NaOCl); conventional needle irrigation (CNI) + saline solution (CNI/SS); CNI + 1% NaOCl (CNI/NaOCl); No irrigation (control). Microbiological samples were collected at three time points: initial (21 days after inoculation), post-irrigation (immediately after irrigation), and final (7 days after irrigation). Data were obtained in CFU mL^-1 and subjected to analysis by ANOVA and Tukey's tests at 5% significance level. The post-irrigation samples did not demonstrate statistical difference between PUI/SS and CNI/SS nor between PUI/NaOCl and CNI/NaOCl (p>0.05), but PUI/NaOCl and CNI/NaOCl had lower CFU mL^-1 number than the other groups (p>0.05). Statistically significant difference was observed between the initial and post-irrigation samples and between the post-irrigation and final samples (p<0.05) in all groups, except in the control. The final samples of all groups presented bacterial counts similar to the initial samples. PUI or CNI with 1% NaOCl contribute to disinfection, but are unable to eradicate E. faecalis from the root canal system.

A irrigação endodôntica visa à limpeza e desinfecção do sistema de canais radiculares. A irrigação ultrassônica passiva (IUP) baseia-se na utilização de um instrumento ultrassônico ativado no interior do canal radicular preenchido com a solução irrigadora. O objetivo deste estudo foi avaliar, ex vivo, a eficácia da IUP na eliminação de Enterococcus faecalis dos canais radiculares. Foram usados 75 dentes humanos unirradiculares extraídos. Após o preparo biomecânico dos canais radiculares, foram inoculados com E. faecalis e incubados a 37 °C por 21 dias. Os espécimes foram distribuídos em cinco grupos (n=15), de acordo com o método de irrigação: IUP + solução salina (IUP/SS); IUP + NaOCl a 1% (IUP/NaOCl); irrigação manual convencional (IMC) + solução salina (IMC/sol); IMC + NaOCl a 1% (IMC/NaOCl); Sem irrigação (controle). Foram realizadas três coletas microbiológicas: inicial (21 dias após a inoculação), pós-irrigação (imediatamente após a irrigação), e final (7 dias após a irrigação). Os dados foram obtidos em UFC mL^-1 e submetidos aos testes de ANOVA e Tukey. A coleta pós-irrigação não demonstrou diferença estatisticamente significante entre IUP/SS e IMC/SS nem entre IUP/NaOCl e IMC/NaOCl (p>0,05), mas IUP/NaOCl e IMC/NaOCl apresentaram menor número de UFC mL^-1 comparado aos outros grupos (p>0,05). Diferença estatisticamente significante foi observada entre as coletas iniciais e pós-irrigação e entre a pós-irrigação e a coleta final (p<0,05) em todos os grupos, exceto no controle. Na coleta final, todos os grupos apresentaram contagem bacteriana similar à coleta inicial. IUP ou IMC com NaOCl a 1% contribuem para a desinfecção, mas não eliminam E. faecalis do sistema de canais radiculares.

Application value of calcium hydroxide agent in root canal disinfection of patients with chronic periapical periodontitis / 中国生化药物杂志

Objective To explore the application value of calcium hydroxide agent in root canal disinfection of patients with chronic periapical periodontitis in stomatology department.Methods 108 cases patients with chronic periapical periodontitis from June 2013 to June 2014 in Cixi Guanhaiwei Zhen Health Centers were randomly divided into study group (n =54) and control group (n=54).The control group received camphor phenol cotton for root canal disinfection, and study group received calcium hydroxide agent.The clinical curative effect between two groups was compared.Results After 7 days’ treatment, the total effective rate was 98.15%in study group, which was significantly higher than 79.63%in control group (χ2 =9.375,P<0.05).After follow up 6 months, the total effective rate was 94.44%in study group, which was significantly higher than 77.78%in control group (χ2 =6.271,P<0.05).The incidence of endodontic interappointment pain (EIP) in study group was 11.11%, which was significantly lower than 25.93%of control group (χ2 =3.93,P<0.05).Conclusion Calcium hydroxide agent has a significant efficacy on in root canal disinfection of patients with chronic periapical periodontitis in stomatology department, could reduce the incidence of EIP and promote healing of chronic periapical periodontitis, which is the first disinfectant in the stomatology department of primary hospital.

Clinical Observation of Yinhe Gargle for Disinfection of Infected Root Canals / 广州中医药大学学报

Objective To evaluate the clinical efficacy of Yinhe gargle on infected root canals. Methods Forty-seven cases of root canal infection ( involving 48 affected teeth) were randomly divided into two groups. The experimental group (22 cases involving 22 affected teeth) was given intracanal medicament with Yinhe gargle, and the control group ( 25 cases involving 26 affected teeth) was given root canal disinfection with camphor phenol. After intracanal medicament for one week, therapeutic effect and safety were evaluated in the two groups. Results ( 1) During root canal disinfection, none of the subjects had adverse reaction such as hypersensitiveness or cauterization of soft tissue. Canal obturation was available after the first intracanal medicament for the infected root canals. (2) After intracanal medicament for one week, the effective rate in the experimental group was 95.45%, and was 100.00%in the control group, the difference being in significant (P>0.05). Conclusion Yinhe gargle has similar disinfection effect to camphor phenol on infected root canals, and it can be used as disinfection medicament for root canals.

Microbiological Evaluation of Different Irrigation Protocols on Root Canal Disinfection in Teeth with Apical Periodontitis: An In Vivo Study

The present in vivo study was designed to evaluate the efficacy of apical negative pressure irrigation (ANP), passive ultrasonic irrigation (PUI) and positive pressure irrigation (PP) in the reduction of intracanal bacteria of dogs' teeth with pulp necrosis and apical periodontitis. Eighty root canals were randomly distributed into 3 experimental and 2 control groups according to the irrigation delivery system: group ANP (n=20), group PUI (n=20), group PP (n=20), group PC (positive control – sterile saline irrigation; n=10) and group NC (negative control - vital pulps not subjected to bacterial inoculation; n=10). The first sample (S1) was collected at baseline, and the second sample (S2) was collected after the disinfection protocols. All samples were seeded in culture media for anaerobic bacteria. CFU counts were analyzed statistically by the Kruskal-Wallis, Dwass-Steel-Critchlow-Fligner post-hoc and Chi-square followed by Tukey like multiple comparisons for proportions (α=0.05). All experimental groups were effective in reducing Gram-positive bacteria compared with PC (p<0.05). Regarding the reduction of Gram-negative bacteria, group ANP was significantly better than PP (p<0.05). No statistically significant difference could be found between PP and PUI (p>0.05). In dog's teeth with apical periodontitis, the use of ANP and PUI can be considered promising disinfection protocols as both delivery systems promoted a significant bacterial reduction.

O presente estudo foi conduzido para avaliar a eficácia da irrigação por pressão apical negativa (ANP), irrigação ultrassônica passiva (PUI) e irrigação por pressão positiva (PP) na redução do número de bactérias presentes nos canais radiculares de dentes de cães com necrose pulpar e lesão periapical. Um total de 80 canais radiculares foram aleatoriamente distribuídos em 3 grupos experimentais e 2 grupos controles, de acordo com o sistema de irrigação empregado: grupo ANP (n=20), grupo PUI (n=20), grupo PP (n=20), grupo PC (controle positivo – irrigação com solução salina; n=10) e grupo NC (controle negativo – tecido pulpar com vitalidade, não submetido à contaminação bacteriana; n=10). A primeira amostra (S1) foi coletada no início do estudo, e a segunda amostra (S2) foi coletada após a utilização dos protocolos de irrigação. Todas as amostras foram semeadas em meio de cultura para micro-organismos anaeróbios. As contagens de unidades formadoras de colônia (cfu) foram analisadas estatisticamente por meio dos testes de Kruskal-Wallis, pós-teste de Dwass-Steel-Critchlow-Fligner e teste do qui-quadrado seguido do teste Tukey like para comparações múltiplas (α=0,05). Todos os grupos experimentais foram efetivos na redução de micro-organismos Gram-positivos, comparados ao grupo PC (p<0,05). Com relação à redução de microorganismos Gram-negativos, o grupo ANP foi significantemente melhor que o PP (p<0,05). Não foi possível observar diferença estatisticamente significante entre os grupos PP e PUI (p>0,05). Conclui-se que, em dentes de cães com periodontite apical, os sistemas de irrigação ANP e PUI podem ser considerados métodos promissores, uma vez que ambos os protocolos promoveram uma redução bacteriana significante.

Research progress on root canal biofilm / 实用口腔医学杂志

Root canal biofilm is frequently detected in the canal wall of infected root canal and the root canal with failed root canal therapy. Due to its special structure and diverse composition, root canal biofilm has the ability of the drug tolerance and antiimmunity, which lead to apical periodontitis. This review summarizes the features of the root canal biofilm and latest clinical methods to remove it.

Clinic Efficacy of Calcium Hydroxide Iodoform Glycerin Paste for Root Canal Disinfection / 中国药房

OBJECTIVE:To evaluate the clinical efficacy of Calcium Hydroxide Iodoform Glycerin(CHIG)paste for root canal disinfection.METHODS:145 patients(145 teeth)requiring root canal therapy were divided randomly into CHIG group,formo-cresol solution group(Group B)and camphor phenol group(Group C).After root canal preparation,the corresponding drugs were introduced into root canal and pulp chamber.The endodontic interappointment pain(EIP)and clinical efficacy in the 3 groups were compared.RESULTS:In Group A,the EIP incidence was the lowest(8.16%)while the effective rate was the highest(97.96%),showing significant differences as compared with Group B(31.91% and 68.09%,respectively)or Group C(34.69% and 71.43%,respectively)(P