Influence of working length and anatomical complexities on the apical root canal filling: a nano-CT study

The present study aimed to compare the filled volume by gutta-percha and sealer in the apical region of the main canal and ramifications, after instrumentation at two different working lengths using nano-computed tomography (nano-CT). Twenty-two premolars with apical ramifications were selected after micro-computed tomography evaluation and were randomly divided into groups for further endodontic instrumentation at two different working lengths: G1 - Root canals shaped 1 mm short of the apical foramen (n=11), and G2 - Root canals shaped at the apical foramen (n=11). After completing root treatment, nano-CT images were acquired, and the filled volume by gutta-percha and sealer in the main canal apical 0-4 mm and 0-1 mm ranges, and apical ramifications were objectively measured by an operator specialized in both radiology and endodontics, blinded for both groups. The Mann-Whitney test was applied to compare both groups regarding the filling of the main canal apical ranges and apical ramifications with a significance level of 5% (α ≤ 0.05). It was observed that root canals shaped at the apical foramen had a larger volume of the main canal filled than root canals shaped 1 mm short of the apical foramen, at both apical ranges (0-4 and 0-1 mm) (p<0.05). Regarding the filling of the apical ramifications, there was no significant difference between groups (p>0.05). In conclusion, the root canals shaped at apical foramen exhibited increased filling volume of the main canal in the apical region. However, neither of both working lengths influenced filling of the apical ramifications.

Investigation of a modified hydraulic calcium silicate-based material - Bio-C Pulpo

This study evaluated the physicochemical, biological, and antimicrobial properties of a new hydraulic calcium silicate-based modified material, and compared it with MTA Repair HP and MTA Angelus. The materials were assessed regarding color luminosity (L), color change, radiopacity, setting time, and ISO 6876:2012 linear flow. Volumetric filling and volume change were evaluated using microcomputed-tomography (µCT). Chemical characterization after 28 days in Hank's Balanced Salt Solution (HBSS) and pH analysis were also assessed. Biological characterization of cytotoxicity and microbiological assessment were also undertaken. Shapiro-Wilk, ANOVA, Levene and post hoc analyses with Bonferroni correction were performed, adopting a 5% significance level (p <0.05). Bio-C Pulpo exhibited the highest L values after 90 days. All tested materials demonstrated color change during the analyses, and had radiopacity above 5 mm Al. MTA Repair HP set faster than Bio-C Pulpo, whereas the latter had the highest linear flow. MTA Repair HP had the highest volumetric filling in µCT analysis. Bio-C Pulpo showed the highest alkalinity during all tested periods, and the highest volumetric loss (above 9%), in comparison with MTA Repair HP and MTA Angelus. Bio-C Pulpo did not form calcium hydroxide after hydration. MTA Repair HP demonstrated the highest cytocompatibility, and Bio-C Pulpo, the highest cytotoxicity. No inhibition halos were observed for any material, and similar higher turbidity values were seen after direct contact. Composition additives used in Bio-C Pulpo modified its properties, and both the absence of calcium hydroxide deposition after hydration, and the related cytotoxicity of this material are of particular concern.

Effect of ethanol-conditioned dentine on sealer penetration into dentinal tubules

Aim: The aim of this study was to evaluate the effect of ethanol-conditioned dentin on endodontic sealer penetration into dentinal tubules by confocal laser scanning microscopy (CLSM). Methods: Forty human maxillary anterior teeth were instrumented and divided into four groups (n = 10) according to the drying methods: 1) wet: vacuum only, 2) paper points: vacuum + absorbent paper points, (3) 70% ethanol: 70% ethanol (1 min) + vacuum + absorbent paper points, and (4) 100% ethanol: 100% ethanol (1 min)  + vacuum + absorbent paper points. All root canals were filled with resin-based endodontic sealer. Four sections from each third (cervical, middle, and apical) were examined by CLSM. Root canal wall perimeter infiltrated by sealer, maximum depth of sealer penetration, percentage of penetrated area, and fluorescence intensity of rhodamine B were measured. Statistical analysis was performed by analysis of variance and Tukey’s tests (α = 0.05). Results: No statistical difference was found when percentage of root canal wall coverage infiltrated by sealer were compared. The groups in which ethanol solutions were used presented greater depth of sealer penetration, higher percentage of penetrated area, and higher fluorescence intensity of rhodamine B (p< 0.05) when compared with the wet and paper point groups. Overall, 100% ethanol produced better results than 70% ethanol, except for rhodamine B intensity (cervical third). In addition, the absorbent paper points drying method behaved better than did vacuum only group, except for rhodamine B intensity (apical third). Conclusion: Ethanol-conditioned dentin improved the penetration of resin-based sealer into dentinal tubules, especially at the concentration of 100%.

Assessment of Ramifications in the Apical Region of Root Canals: A Micro-CT Study in a Brazilian Population

The present study used microcomputed tomography (micro-CT) images to assess the prevalence, number, and location of apical ramifications (ARs) in the root canals of different dental groups in a Brazilian population. Three hundred and sixty-seven extracted human teeth, totaling 475 roots, were scanned by micro-CT at 19.6 µm spatial resolution. The obtained images were evaluated by two observers in consensus, and a descriptive analysis was performed to verify the prevalence, number, and location of ARs in each dental group. Chi-square test was used to compare the prevalence of ARs in different types of roots, and one-way analysis of variance compared the number of ARs in the apical 1 mm, 2 mm, and 3 mm of the root. Significance level was established at 5% (α=0.05). ARs were present in 253 (53.3%) of the 475 roots evaluated. A total of 607 ARs were detected, with the vast majority (530) located at one and two millimeters from the main foramen. The highest prevalence of ARs was observed in maxillary canines (65%); maxillary premolars - single-rooted (83.3%), buccal root (80%), and palatine root (73.3%); mandibular premolars (64.2%); mesiobuccal root of maxillary molars (76.6%); and mesial root of mandibular molars (66.6%). For the Brazilian population, most of the ARs are located in the apical 1 and 2 mm of the root, with greater prevalence in the posterior teeth and maxillary canines. These findings suggest the need for additional attention while planning endodontic treatments, including strategies to effectively clean and fill the apical region.

Dental discoloration caused by Grey-MTAFlow cement: analysis of its physicochemical, biological and antimicrobial properties

Tricalcium silicate-based cement are materials used in reparative and regenerative procedures in endodontics. A recently proposed formulation aimed to enhance handling during clinical use with a versatile material applicable by syringe. Although, the use of bismuth oxide as radiopacifier and grey raw powder are drawbacks considering aesthetics.

Apical root canal cleaning after preparation with endodontic instruments: a randomized trial in vivo analysis

Objectives

This study aimed to evaluate vital pulp tissue removal from different endodontic instrumentation systems from root canal apical third in vivo.

Materials and Methods

Thirty mandibular molars were selected and randomly divided into 2 test groups and one control group. Inclusion criteria were a positive response to cold sensibility test, curvature angle between 10 and 20 degrees, and curvature radius lower than 10 mm. Root canals prepared with Hero 642 system (size 45/0.02) (n = 10) and Reciproc R40 (size 40/0.06) (n = 10) and control (n = 10) without instrumentation. Canals were irrigated only with saline solution during root canal preparation. The apical third was evaluated considering the touched/untouched perimeter and area to evaluate the efficacy of root canal wall debridement. Statistical analysis used t-test for comparisons.

Results

Untouched root canal at cross-section perimeter, the Hero 642 system showed 41.44% ± 5.62% and Reciproc R40 58.67% ± 12.39% without contact with instruments. Regarding the untouched area, Hero 642 system showed 22.78% ± 6.42% and Reciproc R40 34.35% ± 8.52%. Neither instrument achieved complete cross-sectional root canal debridement. Hero 642 system rotary taper 0.02 instruments achieved significant greater wall contact perimeter and area compared to reciprocate the Reciproc R40 taper 0.06 instrument.

Conclusions

Hero 642 achieved higher wall contact perimeter and area but, regardless of instrument size and taper, vital pulp during in vivo instrumentation is not entirely removed.

Evaluation of single visit endodontic treatment and non-surgical retreatment with foraminal enlargment of teeth with apical periodontitis ?

Objetivo: avaliar o tratamento endodôntico (TE) e o retratamento não cirúrgico do canal radicular (RNCCR), associado a ampliação foraminal, realizado em sessão única. Material e Métodos: foram incluídos 125 dentes com periodontite apical e proservação de 6 a 12 meses. O sucesso foi considerado pela ausência de sinais e sintomas e reparo periapical completo ou incompleto. Análises de regressão logística foram utilizadas para identificar fatores associados ao reparo (p<0,05). Resultados: o TE mostrou 71,58% de cicatrização completa e 23,16% de cicatrização aceitável. O RNCCR mostrou 80% e 20% cicatrização completa e aceitável, respectivamente. Idade, sexo, tipo de tratamento e dor pré-operatória não foram estatisticamente significantes para o processo de cicatrização (p>0,05). Os pré-molares apresentaram a maior chance de reparo periapical. O cimento Pulp Canal Sealer mostrou maior chance de reparo periapical quando comparado ao Sealapex (p<0,05). Conclusão: o TE e RNCCR utilizando um protocolo de alargamento foraminal, proporcionaram um prognóstico favorável da cicatrização periapical

Contribution of Bone Marrow-derived Cells to Reparative Dentinogenesis Using Bone Marrow Transplantation Model

INTRODUCTION

The aim of this study was to analyze the contribution of bone marrow-derived cells (BMDCs) to reparative dentinogenesis using bone marrow transplantation (BMT) and pulp capping as an in vivo model.

METHODS

A chimeric mouse model was created through the injection of BMDCs expressing green fluorescent protein (GFP+ BMDCs) from C57BL/6 GFP+ transgenic donor mice into irradiated C57BL/6 wild-type recipient mice (GFP- mice). These GFP- chimeric mice (containing transplanted GFP+ BMDCs) were subjected to microscopic pulp exposure and capping with white mineral trioxide aggregate (n = 18) or Biodentine (Septodont, St Maur-des-Fossés, France) (n = 18) in the maxillary first molar. Maxillary arches from GFP- chimeric mice (with the capped tooth) were isolated and histologically processed 5 (n = 9) and 7 (n = 9) weeks after BMT. Confocal laser microscopy and immunohistochemical analysis were performed to assess the presence of GFP+ BMDCs and the expression of dentin sialoprotein, an odontoblast marker, for those cells contributing to reparative dentinogenesis in the dental pulp.

RESULTS

Confocal laser microscopic analyses evidenced the presence of GFP+ BMDCs in close association with reparative dentin synthesized at the site of pulp exposure in GFP- mice 5 and 7 weeks after BMT. Immunohistochemical analysis revealed that GFP+ BMDCs in close association with reparative dentin expressed DSP, suggesting the contribution of nonresident GFP+ BMDCs to reparative dentinogenesis.

CONCLUSIONS

These data suggest the presence of nonresident BMDCs in reparative dentinogenesis and its contribution to dental pulp regeneration in the pulp healing process.

Multidisciplinary approach for replacement root resorption following severe intrusive luxation: A case report of decoronation

Intrusive luxation is a severe trauma-related event with a high frequency of pulp necrosis and root resorption. A common complication following intrusion is tooth ankylosis, which can extend to progressive replacement root resorption. An increasing infraposition in growing individuals can also occur. Decoronation is a new conservative treatment for cases of tooth ankylosis in young patients who have not finished growing. In this surgical technique, the tooth crown is removed and the root with replacement resorption process remains inside the alveolus. This treatment allows the alveolar bone to continue to develop, thus preserving bone dimensions. The purpose of this article is to report a multidisciplinary case of a young patient with anterior open bite, dental ankylosis, and tooth infraposition affected by intrusive luxation. Decoronation was the treatment of choice for this patient. The patient was then referred to orthodontic treatment to maintain the space of the maxillary right central incisor and open bite correction. After 5 years of follow-up, good clinical and radiologic results were obtained.

Intraoperative discomfort associated with the use of a rotary or reciprocating system: a prospective randomized clinical trial

Objectives

The aim of this randomized, controlled, prospective clinical study was to evaluate patients' intraoperative discomfort during root canal preparations in which either multi-file rotary (Mtwo) or single-file reciprocating (Reciproc) systems were used.

Materials and Methods

Fifty-five adult patients, aged between 25 and 69 years old, with irreversible pulpitis or pulp necrosis participated in this study. Either the mesiobuccal or the distobuccal canals for maxillary molars and either the mesiobuccal or the mesiolingual canals for mandibular molars were randomly chosen to be instrumented with Mtwo multi-file rotary or Reciproc single-file reciprocating systems. Immediately after each canal instrumentation under anesthesia, patient discomfort was assessed using a 1 - 10 visual analog scale (VAS), ranging from ‘least possible discomfort’ (1) to ‘greatest possible discomfort’ (10). The Wilcoxon signed-rank test was used to determine significant differences at p< 0.05.

Results

Little intraoperative discomfort was found in all cases. No statistically significant differences in intraoperative discomfort between the 2 systems were found (p = 0.660).

Conclusions

Root canal preparation with multi-file rotary or single-file reciprocating systems had similar and minimal effects on patients' intraoperative discomfort.

Relationship between Initial Attendance after Dental Trauma and Development of External Inflammatory Root Resorption

Abstract This clinical study aimed to evaluate the relationship of the delay between dental trauma and the initial attendance to the development of external inflammatory root resorption in permanent teeth affected by severe luxation. Sixty-seven patients, aged between 11 and 56 years, presenting 133 injured teeth with closed apex (56 extrusive luxation, 69 lateral luxation and 8 intrusive luxation) were followed up for a minimum of 24 months. The time elapsed between dental trauma and the initial attendance was recorded. The presence of necrotic pulp and external inflammatory resorption for each type of trauma was verified. Fisher’s exact test was used to verify the influence of the initial attendance date at the Dental Trauma Center and the development of inflammatory resorption (p<0.05). The odds ratio was used to check the risk of developing external inflammatory resorption due to delay in seeking treatment. Pulp necrosis was observed in 105 teeth (78.9%) and external inflammatory resorption was detected in 17.8% cases of extrusive luxation (10 teeth), 15.9% of lateral luxation (11 teeth) and 25% of intrusive luxation (2 teeth). For lateral luxation, extended delay between the date of injury and initial attendance influenced the occurrence of external inflammatory resorption (p=0.0174). Patients who began treatment 45 days after the injury were 3.4 times more likely to develop external inflammatory resorption than patients who sought treatment after the trauma. Treatment late after the occurrence of dental trauma can impair the prognosis and result in the development of external inflammatory resorption in luxated teeth.

Avaliação da citotoxicidade de dois cimentos à base de MTA: um estudo in vitro

Objetivo: avaliar o potencial citotóxico de dois cimentos endodônticos à base de MTA (Endoseal e MTA Fillapex), em culturas de fibroblastos humanos, comparando-os com o cimento de referência à base de resina (AH Plus). Material e Métodos: os materiais obturadores foram preparados e eluídos em meio de cultura celular durante 24 horas à 37°C em estufa de CO2. Foram feitas quatro diluições distintas destes meios nas concentrações 1:1, 1:2, 1:4, 1:8 e expostos à cultura celular de fibroblastos humanos da linhagem MRC-5 por 24 horas. A citotoxicidade destes meios de cultura foi avaliada utilizando o ensaio MTT. Os resultados foram transformados em porcentagens de células viáveis com relação ao grupo controle negativo e analisados estatisticamente a partir da Análise de Variância (ANOVA) e pelo teste de Tukey utilizando o software SPSS 15.0 (SPSS Inc, Chicago,IL) (P < 0,05). Resultados: na diluição 1:1 não houve diferença estatística entre os cimentos testados (P > 0,05). Na diluição 1:2 o AH Plus apresentou menor toxicidade quando comparado aos demais cimentos testados (P < 0,05). Nas concentrações de 1:4 e 1:8 o MTA Fillapex apresentou maior citotoxicidade quando comparado ao AH Plus e ao EndoSeal (P < 0,05). Nessas concentrações não foram observadas diferenças estatísticamente significantes entre o AH Plus e o EndoSeal (P > 0,05). Conclusão: a citotoxicidade dos cimentos endodônticos avaliados foi dose dependente. O Endoseal foi menos tóxico que o MTA Fillapex em duas das quatro diluições testadas. Além disso, o AH Plus apresentou citotoxicidade inferior aos dois cimentos à base de MTA em uma das quatro diluições avaliadas.

Clinical efficacy of EDTA ultrasonic activation in the reduction of endotoxins and cultivable bacteria

AIM

This clinical study was conducted to investigate the influence of 17% ethylenediaminetetraacetic acid (EDTA) ultrasonic activation after chemomechanical preparation (CMP) on eliminating/reducing oral bacterial lipopolysaccharides (known as endotoxins) and cultivable bacteria in teeth with pulp necrosis and apical periodontitis.

METHODOLOGY

Samples were taken from 24 root canals at several clinical periods: S1 - before CMP; S2 - after CMP; S3 - after EDTA: G1 - with ultrasonic activation (n = 12) and G2 - without ultrasonic activation (n = 12). Root canals were instrumented using Mtwo rotary files. Culture techniques were used to determine the number of colony-forming units (CFU). Limulus amebocyte lysate (LAL) was used to measure endotoxin levels. Friedman's and Wilcoxon signed-rank tests were used to compare the amount of bacteria and endotoxin levels in each period (P < 0.05).

RESULTS

Endotoxins and cultivable bacteria were recovered in 100% of the initial samples (S1). CMP was effective in reducing endotoxins and bacterial load (all with P < 0.05). Higher values of endotoxin reduction were achieved with EDTA ultrasonic activation [G1, 0.02 EU mL^-1 (range 0.01-0.75)] compared with the no activation group [G2, 1.13 EU mL^-1 (range 0.01-8.34)] (P < 0.05). Regarding bacterial reduction, no statistically significant difference was found in S3, regardless of the group (G1, G2, P > 0.05).

CONCLUSIONS

Chemomechanical preparation was effective in reducing bacteria and endotoxins, but could not completely eliminate them. The ultrasonic activation of EDTA was effective in further reducing endotoxin levels in the root canals of teeth with pulp necrosis and apical periodontitis.

Cytotoxicity Profile of Endodontic Sealers Provided by 3D Cell Culture Experimental Model

Abstract The aim of the present study was to evaluate the cytotoxic effects of five endodontic sealers (AH Plus, Endomethasone N, EndoSequence BC, MTA Fillapex and Pulp Canal Sealer EWT) using a three-dimensional (3D) cell culture model. A conventional bi-dimensional (2D) cell culture model was used as reference technique for comparison. Balb/c 3T3 fibroblasts were cultured in conventional bi-dimensional cell culture and in rat-tail collagen type I three-dimensional cell culture models. Then, both cell cultures were incubated with elutes of freshly mixed endodontic sealers for 24 h. Cell viability was measured by the methyl-thiazol-diphenyltetrazolium assay (MTT). Data were statistically analyzed using ANOVA and the Tukey test at a significance level of p<0.05. All tested sealers exhibited cytotoxic effects; however, cytotoxic effect was culture model- and sealer-dependent. Sealers showed higher cytotoxicity in 2D than in 3D cell culture model (p<0.05). In both conditions, EndoSequence BC showed the lowest cytotoxicity (p<0.05). MTA Fillapex was much more cytotoxic than the other tested endodontic sealers (p<0.05), with the exception of AH Plus in the 2D cell culture model (p>0.05). Endomethasone N and Pulp Canal Sealer EWT showed lower cytotoxic effects than AH Plus in 2D cell culture model (p<0.05); however no statistical differences was observed among these sealers in 3D cell culture model. It may be concluded that cytotoxicity was higher in 2D cell culture compared to 3D cell culture. EndoSequence BC sealer exhibited the highest cytocompatibility and MTA Fillapex the lowest cytocompatibility.

Antimicrobial and cytotoxic effects of phosphoric acid solution compared to other root canal irrigants

Phosphoric acid has been suggested as an irrigant due to its effectiveness in removing the smear layer.

The biocompatibility of a new endodontic paste used in dental trauma

<title>Abstract</title><sec><title>Objective</title><p>This study investigated the short-term subcutaneous tissue reaction of a new endodontic paste, based on the association among calcium hydroxide [Ca(OH)₂], 2% chlorhexidine gel (CHX) and zinc oxide (ZnO) in comparison with a control paste, and the individual substances alone.</p></sec><sec><title>Material and method</title><p>Twenty-four male wistar rats were used. Polyethylene tubes containing the materials were implanted into the dorsal connective tissue of rats. Empty implanted tubes served as controls. The materials used were: Ca(OH)₂+CHX+ZnO paste in two different proportions (2:1:2) and (2:1:3), a control paste, Ca(OH)₂+CHX (2:1), and the substances alone. After time intervals of 2, 3, 7 and 15 days, the animals were euthanized and the specimens prepared for histological processing. Data were evaluated qualitatively according to the levels of tissue repair and the degree of inflammation.</p></sec><sec><title>Result</title><p>On the second day all the materials were observed to cause a severe inflammatory response. On the third day, the pastes Ca(OH)₂+CHX+ZnO (2:1:2) and (2:1:3) showed reduction in degree of inflammation. On seventh day the tissue was already more organized with presence of collagen fibers in all materials. After 15 days it was found that compound Ca(OH)₂+CHX+ZnO (2:1:2) showed areas with no inflammatory infiltrate.</p></sec><sec><title>Conclusion</title><p>The experimental pastes, Ca(OH)₂+CHX+ZnO in two different proportions (2:1:2) and (2:1:3), showed favorable results with respect to biocompatibility, when evaluated for a short-term.</p></sec>

Monitoring the effectiveness of root canal procedures on endotoxin levels found in teeth with chronic apical periodontitis

Objective:

The aim of this study was to monitor the effectiveness of root canal procedures by using different irrigants and intracanal medication on endotoxin levels found in root canals of teeth with chronic apical periodontitis.

Material and Methods:

Thirty root canals of teeth with pulpal necrosis associated with periapical lesions were selected and randomly divided into groups according to the irrigants used: GI - 2.5% NaOCl, GII - 2% chlorhexidine (CHX) gel, and GIII - saline solution (SS) (all, n=10). Samples were collected with sterile/apyrogenic paper points before (S1) and after root canal instrumentation (S2), after use of 17% ethylenediaminetetraacetic acid (EDTA) (S3), and after 30 days of intracanal medication (Ca(OH)₂+SS) (S4). A turbidimetric kinetic Limulus Amebocyte Lysate assay was used for endotoxin measurement.

Results:

Endotoxins were detected in 100% of the root canals investigated (30/30), with a median value of 18.70 EU/mL. After S2, significant median percentage reduction was observed in all groups, irrespective of the irrigant tested: 2.5% NaOCl (99.65%) (GI), 2% CHX (94.27%) (GII), and SS (96.79%) (GIII) (all p<0.05). Root canal rinse with 17% EDTA (S3) for a 3-minute period failed to decrease endotoxin levels in GI and a slight decrease was observed in GII (59%) and GIII (61.1%) (all p>0.05). Intracanal medication for 30 days was able to significantly reduce residual endotoxins: 2.5% NaOCl (90%) (GI), 2% CHX (88.8%) (GII), and SS (85.7%) (GIII, p<0.05). No differences were found in the endotoxin reduction when comparing s2 and s4 treatment groups.

Conclusion:

Our findings demonstrated the effectiveness of the mechanical action of the instruments along with the flow and backflow of irrigant enduring root canal instrumentation for the endotoxin removal from root canals of teeth with chronic apical periodontitis. Moreover, the use of intracanal medication for 30 days contributed for an improvement of endotoxin reduction.

Evaluation of cytotoxicity, antimicrobial activity and physicochemical properties of a calcium aluminate-based endodontic material

A calcium aluminate-based endodontic material, EndoBinder, has been developed in order to reduce MTA negative characteristics, preserving its biological properties and clinical applications.

OBJECTIVES

The aim of this study was to evaluate the cytotoxicity, antimicrobial activity, pH, solubility and water sorption of EndoBinder and to compare them with those of white MTA (WMTA).

MATERIAL AND METHODS

Cytotoxicity was assessed through a multiparametric analysis employing 3T3 cells. Antimicrobial activity against Enterococcus faecalis (ATCC 29212), Staphylococcus aureus. (ATCC 25923) and Candida albicans (ATCC 10556) was determined by the agar diffusion method. pH was measured at periods of 3, 24, 72 and 168 hours. Solubility and water sorption evaluation were performed following ISO requirements. Data were statistically analyzed by ANOVA and Tukey`s test with a significance level of 5%.

RESULTS

EndoBinder and WMTA were non-cytotoxic in all tested periods and with the different cell viability parameters. There was no statistical differences between both materials (P>.05). All tested materials were inhibitory by direct contact against all microbial strains tested. EndoBinder and WMTA presented alkaline pH in all tested times with higher values of pH for WMTA (P<.05). Both materials showed values complying with the solubility minimum requirements. However, EndoBinder showed lower solubility than WMTA (P<.05). No statistical differences were observed regarding water sorption (P>.05).

CONCLUSION

Under these experimental conditions, we concluded that the calcium aluminate-based endodontic material EndoBinder demonstrated suitable biological and physicochemical properties, so it can be suggested as a material of choice in root resorption, perforations and root-end filling.

Localización efectiva de un segundo conducto radicular en incisivos inferiores mediante magnificación, radiografía y diafanización

Objetivo: Evaluar in vitro, la efectividad del método visual y radiográfico, comparándolos con la técnica de diafanización en la detección del segundo conducto radicular de incisivos inferiores tratados endodónticamente. Material y métodos: Fueron analizados 133 dientes incisivos inferiores permanentes, tratados endodónticamente, a través de métodos visuales (con y sin auxilio de magnificación), radiográficos y de diafanización. El análisis radiográfico fue realizado en negatoscopio utilizando una lupa estereoscópica (10X). Posteriormente, fue realizada la remoción completa de la obturación provisional para la exploración visual con y sin auxilio de microscopio clínico (MO) en un aumento de 12X. Finalmente los dientes fueron diafanizados y almacenados en salicilato de metila para posterior análisis. Dos evaluadores calibrados registraron los datos referentes a la presencia o no del segundo conducto radicular para cada uno de los métodos utilizados. Resultados: El análisis radiográfico mostró la presencia del segundo conducto en 24 dientes (18,05%). Visualmente, fue encontrado en 4 dientes (3,00%) sin magnificación y en 16 dientes (12,03%) con ayuda del MO. A través de la diafanización, 34 dientes (25,95%) presentaron segundo conducto. Conclusiones: La asociación de técnicas radiográficas y la magnificación visual obtenida con la utilización del MO se muestran como los aliados clínicos más efectivos para la localización del segundo conducto radicular en incisivos inferiores.

Clinical and radiographic features of Hutchinson-Gilford progeria syndrome: A case report

Hutchinson-Gilford progeria syndrome (HGPS) is a rare dysmorphic syndrome characterized by several features of premature aging with clinical involvement of the skin, bones, and cardiovascular system. HGPS has an estimated incidence of one in four million to one in eight million births. The main clinical features of HGPS include short stature, craniofacial dimorphism, alopecia, bone fragility, and cardiovascular disorders. The most frequent cause of death is myocardial infarction at a mean age of 13 years old. Dental manifestations include delayed development and eruption of teeth, discoloration, crowding and rotation of teeth, and displaced teeth. Cone beam computed tomography images revealed the absence of the sphenoid, frontal, and maxillary sinus, flattening of the condyles and glenoid fossa, and bilateral hypoplasia of the mandibular condyles. The disease is caused by mutations in lamin A/C (LMNA). Here, we present a case report of an 11-year-old boy with classical features of HGPS, which was caused by a de novo germ-line mutation (C1824T, G608G) in exon 11 of the LMNA gene. Some uncommon HGPS-associated features in our patient, such as alterations in the facial sinuses and hypoplasia of the condyles, contributed to the expansion of the phenotypic spectrum of this syndrome from a dentomaxillofacial perspective.

Long-term cytotoxic effects of contemporary root canal sealers

OBJECTIVES

The aim of the present study was to investigate the effects of root canal sealers on the cytotoxicity of 3T3 fibroblasts during a period of 5 weeks.

MATERIAL AND METHODS

Fibroblasts (3T3, 1×105 cells per well) were incubated with elutes of fresh specimens from eight root canal sealers (AH Plus, Epiphany, Endomethasone N, EndoREZ, MTA Fillapex, Pulp Canal Sealer EWT, RoekoSeal and Sealapex) and with elutes of the same specimens for 5 succeeding weeks after immersing in simulated body fluid. The cytotoxicity of all root canal sealers was determined using the MTT assay. Data were analyzed using ANOVA and Tukey's test.

RESULTS

RoekoSeal was the only sealer that did not show any cytotoxic effects (p<0.05). All the other tested sealers exhibited severe toxicity initially (week 0). MTA Fillapex remained moderately cytotoxic after the end of experimental period. Toxicity of the other tested sealers decreased gradually over time. The evaluated root canal sealers presented varying degrees of cytotoxicity, mainly in fresh mode.

CONCLUSIONS

RoekoSeal had no cytotoxic effect both freshly mixed and in the other tested time points. MTA Fillapex was associated with significantly less cell viability when compared to the other tested root canal sealers.

Influence of the apical enlargement size on the endotoxin level reduction of dental root canals

Gram-negative bacteria play an essential role in endodontic infections because they have virulence factors such as endotoxin. Due to its potential cytotoxic activity, special attention has been given to the removal/neutralization of this endotoxin in the root canal system.

Evaluation of gelatinases, tissue inhibitor of matrix metalloproteinase-2, and myeloperoxidase protein in healthy and inflamed human dental pulp tissue

INTRODUCTION

The aim of this study was to compare the gelatinolytic activity of matrix metalloproteinase (MMP)-2 and MMP-9 and the expression of tissue inhibitor of matrix metalloproteinase (TIMP)-2 and myeloperoxidase protein (MPO) in clinically healthy human pulp and inflamed pulp tissue specimens.

METHODS

Twenty dental pulps clinically diagnosed as inflammatory tissues and 20 healthy pulp tissues from enclosed third molars were harvested and evaluated. The gelatinolytic activity for MMP-2 and MMP-9 was assessed by using the zymography technique, TIMP-2 gene expression was evaluated using the enzyme-linked immunosorbent assay, and MPO was determined using the MPO assay.

RESULTS

Data showed increased levels of MMP-9, active MMP-2, TIMP-2, and MPO in inflammatory pulp tissues compared with healthy tissues (P < .05). No statistical difference could be observed for pro-MMP-2 (P > .05).

CONCLUSIONS

Although all samples were associated with MMP-2 expression, the active form of this MMP was observed only in inflamed pulps. Inflamed pulps showed an up-regulation of MMP-9, TIMP-2, and MPO.

Open apex type III dens invaginatus: a rare case report of an endodontic retreatment with an anatomical redesign

Dens invaginatus is a critical condition for endodontic treatment. It frequently presents a complex internal anatomy and might be associated with incomplete root and apical development. This article presents one of the few reported cases of endodontic retreatment of Type III dens invaginatus. First, the internal anatomy was modified using burs under an operating microscope. Next, conventional chemical and mechanical preparation with hand files and 2.5% sodium hypochlorite was performed. Finally, an intracanal dressing with calcium hydroxide was used for nine months, at which point the anatomical features in the root canal system could be accessed. Adequate periradicular healing was observed and regression of the lesion was noted at the two-year follow-up. This case reinforces the idea that knowledge about the biologic aspects of endodontics, combined with adherence to technical standards, is helpful in resolving complex cases.

A feasibility study for the analysis of reparative dentinogenesis in pOBCol3.6GFPtpz transgenic mice

AIM

To examine the feasibility of using the pOBCol3.6GFPtpz [3.6-green fluorescent protein (GFP)] transgenic mice as an in vivo model for studying the biological sequence of events during pulp healing and reparative dentinogenesis.

METHODOLOGY

Pulp exposures were created in the first maxillary molar of 12-16-week-old 3.6-GFP transgenic mice with CD1 and C57/Bl6 genetic background. Direct pulp capping on exposed teeth was performed using mineral trioxide aggregate followed by restoration with a light-cured adhesive system (AS) and composite resin. In control teeth, the AS was placed in direct contact with the pulp. Animals were euthanized at various time points after pulp exposure and capping. The maxillary arch was isolated, fixed and processed for histological and epifluorescence analysis to examine reparative dentinogenesis.

RESULTS

Analysis of teeth immediately after pulp exposure revealed absence of odontoblasts expressing 3.6-GFP at the injury site. Evidence of reparative dentinogenesis was apparent at 4 weeks in 3.6-GFP mice in CD1 background and at 8 weeks in 3.6-GFP mice with C57/Bl6 background. The reparative dentine with both groups contained newly formed atubular-mineralized tissue resembling a dentine bridge and/or osteodentine that was lined by cells expressing 3.6-GFP as well as 3.6-GFP expressing cells embedded within the atubular matrix.

CONCLUSION

This study was conducted in a few animals and did not allow statistical analysis. The results revealed that the 3.6-GFP transgenic animals provide a unique model for direct analysis of cellular and molecular mechanisms of pulp repair and tertiary dentinogenesis in vivo. The study also shows the effects of the capping material and the genetic background of the mice in the sequence and timing of reparative dentinogenesis.

Apexification with a new intra-canal medicament: a multidisciplinary case report

Dental trauma generally requires multidisciplinary planning and treatment for good prognosis. When immature teeth are traumatized to a degree where pulp necrosis ensues, the objective of root canal treatment should be apexogenesis and root maturation. Apexification of the root is the conventional choice, which involves cleaning the canal and filling it with a temporary medication that stimulates the formation of a calcific apical barrier. Dental Trauma Service of Piracicaba Dental School, State University of Campinas (UNICAMP), Brazil employs a dressing for apexification treatments with calcium hydroxide, chlorhexidine gel 2% and zinc oxide. This paper reports the case of a dental trauma of the maxillary central incisors and subluxation on teeth 11, 12 and 21 that were treated with multidisciplinary collaboration (Endodontics, Periodontology and Operative Dentistry) to improve prognosis. After five-years there were no pathological conditions and the teeth showed every evidences of success.

Evaluation of the colour change in enamel and dentine promoted by the interaction between 2% chlorhexidine and auxiliary chemical solutions

To evaluate the colour change in enamel and dentine, promoted by interaction of 2% chlorhexidine gluconate (CHX) with 5.25% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid (EDTA). Fragments containing enamel and dentine were obtained from the crowns of extracted bovine incisors. Before and after immersion of the samples in the substances, they were evaluated with reference to the colour of the enamel and dentine. The values obtained in numerical scores were subjected to statistical analysis using Wilcoxon test. A colour change in the enamel and dentine in groups treated with CHX gel + NaOCl and CHX gel + NaOCl + EDTA, and a change in colour only in the dentine in groups treated with CHX solution + NaOCl and CHX solution + NaOCl + EDTA. When used prior to NaOCl, CHX has the ability to induce a colour change in dental structures.

Effect of chlorhexidine and ethanol on the durability of the adhesion of the fiber post relined with resin composite to the root canal

INTRODUCTION

The aim of this study was to investigate the effects of pretreatment of gel chlorhexidine and ethanol on the bond strength and durability of the adhesion of the fiber post relined with resin composite to the root dentin.

METHODS

Sixty bovine incisor roots were divided into four groups: irrigation with physiologic solution (control), 5 minutes with chlorhexidine, 1 minute with ethanol, and 5 minutes with chlorhexidine followed by 1 minute with ethanol. Fiber posts relined with resin composite were cemented with RelyX ARC (3M ESPE, St Paul, MN) and a self-etching adhesive system Clearfil SE Bond (Kuraray, Kurashiki, Japan). Each group was randomly divided into three subgroups: 24 hours of water storage, 12 months of water storage, and 12 months of oil storage. All roots were sectioned transversely in the coronal, middle, and apical regions, producing 1-mm thick slices, and the push-out test was performed. Statistical analysis was performed using analysis of variance and the Tukey test for post hoc comparisons (α = 0.05).

RESULTS

Immediate groups showed similar bond strength values with or without chlorhexidine and/or ethanol pretreatment (P > .05). A significant decrease in the bond strength in the control group was observed after 12 months of storage in water and oil (P < .05). The use of chlorhexidine- and/or ethanol-preserved bond strength in the groups stored in water and oil for 12 months (P < .05).

CONCLUSIONS

Chlorhexidine and/or ethanol pretreatment were capable of preserving the bond strength of the fiber post relined with resin composite to root dentin for 12 months.

Thickness of dentine in mesial roots of mandibular molars with different lengths

AIM

To measure the minimum thickness of the distal (furcal) root dentine associated with the buccal and lingual canals of the mesial roots of mandibular first molars with different lengths.

METHODOLOGY

The mesial roots of 285 mandibular first molars were allocated into three groups according to their length: group I - long (24.14 mm +/- 0.85), group II - medium (22.10 mm +/- 0.65) and group III - short (19.97 mm +/- 0.75). The minimum thickness of the distal (furcal) root dentine associated with the buccal and lingual canals of the mesial roots 2 mm below the furcation was measured. The distance between the buccal and lingual canals, and the depth of concavity in the distal surface of the mesial roots were also measured. anova and Tukey-Kramer were used to test for significant differences among the groups.

RESULTS

The minimum thickness of the distal wall of the mesiobuccal canal was significantly different (P < 0.05) between group I (long) and III (short), with long teeth having the smallest mean values. No significant difference was found in the thickness of the distal wall of the mesiolingual canal among the groups studied (P > 0.05). The shortest distance between the mesiobuccal and the mesiolingual canals was observed in group III (P < 0.05). The distal (furcal) concavity was deeper in group I (P < 0.05) when compared with the other groups.

CONCLUSION

There was a significant difference in the minimum thickness of the distal (furcal) root wall of the mesiobuccal canal of mandibular first molars 2 mm below the furcation between group I (long) and group III (short) teeth. The thinnest walls were found in the longest teeth. The deepest concavities in the distal (furcal) walls of the mesial roots were found in the longest roots.

Concentration of hydrogen ions in several calcium hydroxide pastes over different periods of time

The purpose of this in vitro study was to measure the concentration of hydrogen ions (pH) of calcium hydroxide [(Ca(OH)2] pastes combined with different vehicles over 7 periods of time. The Ca(OH)2 was manipulated with the following vehicles: i: sterile water; ii: iodoform plus sterile water; iii: local anesthetics (Lydocaine 2% with 1: 100,000 epinephrine); iv: polyethyleneglycol; v: glycerin; vi: 2.0% chlorhexidine gel; vii: camphorated paramonochlorophenol (CMCP); viii: (CMCP) + glycerin; and ix: polyethyleneglycol plus CMCP. The pastes were made on a glass plate to toothpaste consistency and the pH was measured at the following times: 5 min, 1, 24, 48 h; 7, 14 and 28 days. The data were statistically analyzed (Kruskal-Wallis at p<0.05). At 5 min, 1 and 24 h, the pH of all tested pastes ranged from 13.05 to 11.16. At 48 h and 7 days the pH of all tested pastes ranged from 11.66 to 8.92. At 14 and 28 days almost all pastes had pH means lower than 10. In conclusion, the mean pH of all tested calcium hydroxide pastes decreased with the time. Pastes made with aqueous vehicles (especially with sterile water), followed by oily vehicles (especially with CMCP + glycerin), held the highest pH means over the periods of time tested.

In vitro evaluation of the effectiveness of the chemomechanical preparation against Enterococcus faecalis after single- or multiple-visit root canal treatment

The purpose was to assess the elimination of Enterococcus faecalis in vitro in human mandibular premolars after chemomechanical preparation with or without the use of a calcium hydroxide dressing. After 60 days of contamination with E. faecalis, the root canals were prepared using the Crown-Down technique combined with 2% chlorhexidine gel irrigation. Then, the specimens were divided into two experimental groups, treated in a single visit or in multiple visits, and two control groups. The multiple-visit group received a dressing with calcium hydroxide for 14 days (Calen) and the single-visit group did not receive any medication. In the two control groups, the canals were filled with BHI after chemomechanical preparation with 2% chlorhexidine gel or distilled water. Microbial samples were taken from the root canals for colony forming unit count for each phase of the treatment using sterile paper points inside the root canal lumen. Data were ranked and analyzed by the Kruskal-Wallis statistical test. The residual microbial colonies were then assessed. The results showed that chemomechanical preparation using 2% chlorhexidine gel with no intra-canal dressing reduced by 100% the E. faecalis contamination of the root canal lumen. The calcium-hydroxide group that received the 14-day intra-canal dressing allowed a small number of bacteria to grow between visits, but without statistical differences between groups.

Radiographic prevalence of root canal ramifications in a sample of root canal treatments in a Brazilian Dental School

The aim of this study was to radiographically investigate the presence of root canal ramifications found after endodontic treatment, and to determine any relationship between their presence and the type of the auxiliary chemical substance used. The study evaluated 1,470 endodontic treatments performed by final year undergraduate students at the Dental School of Piracicaba, State University of Campinas (UNICAMP), SP, Brazil, during the period from 1998 to 2000. The X-rays taken during treatment were evaluated in order to establish the presence of ramifications of the root canal system. The initial X-ray did not show the presence of any canal ramifications. After filling, X-rays showed only 3 ramification types: 3.06% of lateral canals, 2.99% of apical deltas, and 0.1% of interradicular canals. The maxillary premolars showed the highest number of lateral canals (n = 13), followed by mandibular premolars (n = 10) and maxillary incisors (n = 10). Apical deltas were mostly found in mandibular molars (n = 14), followed by maxillary incisors (n = 9). Only mandibular molars had interradicular canals. The detection of ramifications increased with the use of EDTA. However, no statistically significant relationship was found between the type of auxiliary chemical substance used and the number of root canal ramifications detected after root canal filling. It was concluded that the frequency of root canal ramifications found radiographically was low in treatments performed by undergraduate students.

Antimicrobial effect and pH of chlorhexidine gel and calcium hydroxide alone and associated with other materials

The purposes of this study were to evaluate the effectiveness of 2% chlorhexidine (CHX) gluconate gel, calcium hydroxide [Ca(OH)2] and their combination with iodoform and zinc oxide powder as intracanal medications against select microorganisms, and to measure the pH changes caused by these medications. Antimicrobial activity was determined by the agar diffusion method. The zones of growth inhibition were measured and the results were analyzed statistically by Kruskal-Wallis test (p<0.05). The pH of the pastes was measured right after preparation, after 24 h and 1 week later. The largest mean zones of microbial inhibition were produced by 2% CHX gel, followed by Ca(OH)2 + 2% CHX gel + iodoform, Ca(OH)2 + 2% CHX gel, Ca(OH)2 + 2% CHX gel + zinc oxide, and Ca(OH)2 + water. The mean pH of all medications stayed above 12.0 during the whole experiment, except for CHX gel (pH=7.0). The results of this study showed that all medications had antimicrobial activity, but the most effective against the tested microorganisms were 2% CHX gel, followed by its combination with Ca(OH)2 and iodoform.

Filling of artificial lateral canals and microleakage and flow of five endodontic sealers

AIM

To evaluate the flow characteristics of AH Plus, Epiphany Root Canal Sealant, Endométhasone, Pulp Canal Sealer (EWT) and Sealapex and their ability to fill artificial lateral canals and prevent microleakage.

METHODOLOGY

Flow of the sealers was analysed using the American Dental Association (ADA) 57 and the International Standards Organization (ISO) 6,876 specifications. Two lateral canals were produced in the middle and apical third of 64 roots using 0.1 mm cylindrical drills. Lateral condensation of gutta-percha or Resilon and one or other of the sealers were used to fill the root canals. Buccal-lingual digital radiographs were exposed. After the sealer had set, the roots were immersed in Indian ink and cleared in methyl salicylate. The extent of filling and dye penetration were measured on the buccal and lingual root surfaces under 30 x magnification with a stereoscope.

RESULTS

AH Plus, Epiphany and Pulp Canal Sealer (EWT) complied with ADA 57 and ISO 6,876 specifications. Sealapex complied with the ADA 57 specification but not with ISO 6,876. Endométhasone did not comply with either specification. Filling of lateral canals was similar for the five sealers tested. Dye leakage demonstrated that AH Plus, Epiphany and Sealapex permitted less leakage than Pulp Canal Sealer (EWT) (P < 0.05).

CONCLUSIONS

All the sealers flowed into the 0.1 mm artificial lateral canals. AH Plus, Epiphany and Sealapex allowed less linear leakage than Pulp Canal Sealer (EWT). The flow of Endométhasone did not comply with either ADA 57 or ISO 6,876 specifications and Sealapex did not comply with ISO 6,876.

Degradation of trans-polyisoprene over time following the analysis of root fillings removed during conventional retreatment

AIM

To evaluate in vivo degradation of root filling materials over time.

METHODOLOGY

Thirty-six root filled teeth with or without periapical lesions were selected. Teeth with poor coronal restoration were not included. The teeth had been root filled 3-30 years previous and were scheduled for conventional retreatment. The association of root canal treatment, age, periapical lesion and root filling degradation was investigated. The filling material was removed from the root canal using files and no solvent. Trans-1,4-polyisoprene was isolated through solubilization of root filling remnants in chloroform followed by filtration and centrifugation. Gel permeation chromatography (GPC) and infrared spectroscopy (FT-IR) were utilized to study the occurrence and degree of degradation. The GPC and FT-IR data were collected for each sample and analysed statistically using the Kruskal-Wallis test.

RESULTS

Degradation of trans-1,4-polyisoprene was a slow process. The process was identified as an oxidation reaction through the production of carboxyl and hydroxyl groups. Compared with the control group, significant molar mass decrease was noted after 15 years (P = 0.0146) in teeth with no periapical lesions. However, in teeth associated with periapical lesions the number of years for significant degradation was reduced to 5 (P = 0.0009).

CONCLUSION

Polyisoprene degrades inside root canals as an oxidative process. The presence of periapical lesions was associated with a more rapid onset of degradation.

In vitro antimicrobial activity of sodium hypochlorite and chlorhexidine against selected single-species biofilms

AIM

To investigate the antimicrobial activity of 2.5% and 5.25% sodium hypochlorite and 2.0% chlorhexidine gel and liquid as endodontic-irrigating substances against selected single-species biofilms.

METHODS

Single-species biofilms of Enterococcus faecalis, Staphylococcus aureus, Candida albicans, Prevotella intermedia, Porphyromonas gingivalis, Porphyromonas endodontalis and Fusobacterium nucleatum were generated on a cellulose nitrate membrane placed on agar medium. The biofilms were then immersed in the endodontic-irrigating substances for 30 s and also for 5, 10, 15, 30 and 60 min, with and without mechanical agitation. Sterile saline was used as control. After each time period, the membrane filters were then transferred to tubes containing 2 mL of fresh broth medium plus neutralizers (in order to prevent the residual action of the tested substances). The micro-organisms were suspended using a vortex, and the inoculum was serially diluted 10-fold. Aliquots of the dilutions were plated on 5% sheep blood agar medium, and incubated under adequate gaseous conditions. Colony-forming units were calculated. The samples were compared using the Friedman and Tukey test, when necessary, at a significance level of P < 0.05.

RESULTS

Mechanical agitation promoted the effectiveness of the antimicrobial agents, resulting in less time to eliminate the same micro-organisms, except for S. aureus with 2.5% NaOCl. Antimicrobial agents in liquid presentation, especially 5.25% NaOCl and 2% chlorhexidine, killed the tested micro-organisms more rapidly. Saline did not inhibit the growth of any of the tested micro-organisms, with or without agitation, being statistically different (P < 0.05) from NaOCl and chlorhexidine. P. intermedia, P. gingivalis, P. endodontalis and F. nucleatum were eliminated in 30 s by all antimicrobial agents, with our without agitation, in contrast with the facultative and aerobe strains.

CONCLUSIONS

Mechanical agitation improved the antimicrobial properties of the chemical substances tested using a biofilm model, favouring the agents in liquid presentation, especially 5.25% NaOCl and 2% chlorhexidine.

Effect of Chemical Irrigants on the Bond Strength of a Self-Etching Adhesive to Pulp Chamber Dentin

The aim of this study was to evaluate the influence of endodontic irrigants on adhesion to pulp chamber dentin. Seventy crowns of bovine incisors were cut to expose the pulp chamber. Specimens were divided into seven groups, according to the irrigant solution used: G1, 0.9% sodium chlorite (control); G2, 5.25% NaOCl; G3, 5.25% NaOCl + 17% EDTA; G4, 2% chlorhexidine solution; G5, 2% CHX solution + 17% EDTA; G6, 2% chlorhexidine in a gel base; and G7, 2% CHX gel + 17% EDTA. After irrigation, Clearfil SE Bond was applied to pulp chamber dentin, followed by Filtek Z250 composite. Six rectangular sticks were obtained from each specimen and dentin/resin interface was tested in tension. Bond strength means were analyzed by ANOVA and Tukey test. There was a significant decrease in bond strength associated to NaOCl, whereas chlorhexidine irrigation showed no effects on adhesion. It was concluded that endodontic irrigants affected differently bond strength to pulp chamber dentin.

In vitro evaluation of the antimicrobial activity of calcium hydroxide combined with chlorhexidine gel used as intracanal medicament

The aim of this study was to investigate the antimicrobial activity of calcium hydroxide (Ca(OH)2) combined with 2% chlorhexidine gluconate (CHX) gel against endodontic pathogens and to compare the results with the ones achieved by Ca(OH)2 mixed with sterile water and by CHX gel alone. Two methods were used: the agar diffusion test and the direct contact test. Ca(OH)2 + 2% CHX gel produced inhibitory zones ranging from 2.84 to 6.5 mm, and required from 30 seconds to 6 hours to eliminate all tested microorganisms. However, 2% CHX gel showed the largest microbial growth zones from 4.33 to 21.67 mm, and required 1 minute or less to inhibit all tested microorganisms. A paste of Ca(OH)2 plus sterile water inhibited only the microorganisms with which it was in direct contact and required from 30 seconds to 24 hours to kill all tested microorganisms. In conclusion, 2% CHX gel + Ca(OH)2 showed better antimicrobial activity than Ca(OH)2 manipulated with sterile water.