Ultrasonic agitation reduces the time of calcium hydroxide antimicrobial effect and enhances its penetrability.

OBJECTIVES: The objective of the present work was to evaluate the ultrasonic agitation, time and vehicle (propylene glycol or distilled water) on the antimicrobial potential and penetrability of calcium hydroxide pastes on infected dentin by means of Confocal Laser Scanning Microscopy (CLSM) and microbiological culture (MC). MATERIALS AND METHODS: Dentin specimens were infected with Enterococcus faecalis using a new contamination protocol of 5 days. The specimens were divided into eight groups and dressed with the pastes for 7 or 15 days: G1) calcium hydroxide (CH) + propylene glycol (prop)/7 days (d), G2) CH + prop/7d + ultrasonic agitation (U), G3) CH + distilled water (dw)/7d, G4) CH + dw/7d + U, G5) CH + prop/15d, G6) CH + prop/15d + U, G7) CH + dw/15d, G8) CH + dw/15d + U. The ultrasonic activation was made for 1 min in both directions with a plain point insert. After medications removal, the images obtained by CLSM showed the viable (green) and dead (red) bacteria with Live and Dead dye. By the MC, the dentinal wall debris obtained by burs were collected for colony counts. For the penetration test, the Rodamine B dye was added to the CH pastes and analyzed by CLSM. RESULTS: The 7 and 15-days CH + prop+U pastes performed better antimicrobial efficacy, followed by the CH + dw+U/15d paste. CONCLUSIONS: All pastes demonstrated better penetration and antimicrobial activity against E. faecalis when agitated with ultrasound, even in periods of up to seven days. The propylene glycol vehicle showed better results. CLINICAL RELEVANCE: Agitation of the dressing that remains for less time inside the root canal can optimize the decontamination of endodontic treatment.

Evaluation of calcium (Ca2+) and hydroxide (OH-) ion diffusion rates of indirect pulp capping materials.

INTRODUCTION: The aim of this study was to evaluate and compare the calcium (Ca2+) and hydroxide (OH-) ion release of 4 artificially produced pulp capping materials (MTA, Biodentin, TheraCal LC, Calsimol) used for indirect pulp capping treatment. METHODS: In total, 70 freshly extracted human third molar teeth were used for the study. Cavities of extracted teeth were prepared by round burs. The remaining dentin thickness (1 ± 0.3 mm) tissue was measured by a micrometer and cone beam computerized tomography. Indirect pulp capping was performed in the cavities using Calcimol, MTA, TheraCal LC and Biodentin. The leached Ca2+ were measured using optical emission spectrometry and the release of OH- ions using a pH meter. The measurements were performed after 24 hours, 7 days and 28 days in saline solution. Statistical analysis was performed using 1-way and 2-way analysis of variance (ANOVA) tests (p<0.05). RESULTS: Ca2+ ions were detected in treated saline solution during the experimental period for all materials. All the measurements of Biodentin and Theracal LC levels for Ca2+ ions were higher than those of the other materials (p<0.05). For all materials, Ca2+-ion release increased during the first 7 days followed by a linear decrease during the subsequent study periods. The Biodentine group showed the highest OH- ion rates compared to the other materials in the 24-hour examination period, while the scores gradually decreased during the subsequent measurement periods (p<0.05). CONCLUSIONS: Tricalcium silicate materials such as Biodentine and TheraCal LC used in this study may be preferable for indirect pulp capping because of their stimulation of hard tissue formation and ion-releasing ability.

Effect of a Low Surface Tension Vehicle on the Dentinal Tubule Penetration of Calcium Hydroxide and Triple Antibiotic Paste.

INTRODUCTION: The purpose of this study was to evaluate dentinal tubule penetration (DTP) of calcium hydroxide (CH) and triple antibiotic paste (TAP) when performed with distilled water (DW) or a low surface tension liquid (ie, propylene glycol [PG]). METHODS: Root apices of 40 single-rooted premolars were removed to obtain 14-mm roots in length. Root canals were enlarged to simulate immature teeth. After smear layer removal, the roots were randomly divided into 4 groups (n = 10) according to the root canal medicaments and the vehicles used: group 1:TAP + DW, group 2: TAP + PG, group 3: CH + DW, and group 4:CH + PG. Root canal medicaments were labeled with 0.1% rhodamine and applied into the canals using a Lentulo spiral. Specimens were molded into acrylic blocks, and 1-mm-thick sections were obtained from the middle third of each root. Specimens were mounted onto glass slides and scanned under a confocal laser scanning microscope. DTP depth, percentage, and area were measured using imaging software. Kruskal-Wallis and Mann-Whitney U tests were used for statistical analysis. The level of significance was set at P < .05. RESULTS: No significant difference was found among the experimental groups in terms of both percentage and depth of DTP (P > .05). CH had a lower penetration area compared with TAP regardless of the vehicle used (P < .05). CONCLUSIONS: A low surface tension vehicle did not alter the penetration of CH and TAP.

Application of 17% EDTA Enhances Diffusion of (45)Ca-labeled OH(-) and Ca(2+) in Primary Tooth Root Canal.

Proper cleaning of the root canal is key to the success of endodontic treatment as it allows more effective diffusion of medication throughout the dentinal tubules. The aim of this in vitro study was to investigate the efficacy of 17% ethylenediaminetetraacetic acid (EDTA) in enhancing diffusion of hydroxyl (OH(-)) and calcium ions (Ca(2+)) throughout the root canal in primary teeth. The canals of 25 primary tooth roots were cleaned with endodontic files and 1% sodium hypochlorite. Three groups (G) were then established: GI, in which final irrigation was performed with 1% sodium hypochlorite; GII, in which 17% EDTA was used; and GIII, in which no irrigation was performed. The roots canals in GI and GII were filled with a calcium hydroxide-based paste labeled with the radioisotope calcium-45. Diffusion of OH(-) was detected with pH strips and Ca(2+) analyzed by measuring radioactivity in counts per min. Group II differed statistically from the other groups in diffusion of OH(-) at 24 hr (p<0.05), but no significant difference among groups was found at the day 7 evaluation; GII also differed statistically from the other groups in diffusion of Ca(2+) at 24 hr (p<0.05). These results suggest that application of 17% EDTA in primary tooth enhances diffusion of OH(-) and Ca(2+).

Assessment of ion diffusion from a calcium hydroxide-propolis paste through dentin

This study evaluated the ability of ions from a non-alcoholic calcium hydroxide-propolis paste to diffuse through dentinal tubules. Thirty-six single-rooted bovine teeth were used. The tooth crowns were removed, and the root canals were instrumented and divided into 3 groups: Group 1 - calcium hydroxide-propylene glycol paste; Group 2 - calcium hydroxide-saline solution paste; Group 3 - calcium hydroxide-propolis paste. After the root canal dressings were applied, the teeth were sealed and placed in containers with deionized water. The pH of the water was measured after 3, 24, 72 and 168 hours to determine the diffusion of calcium hydroxide ions through the dentinal tubules. All of the pastes studied promoted the diffusion of calcium hydroxide ions through the dentinal tubules. Associating propolis to calcium hydroxide resulted in a pH increase, which occurred with greater intensity after 72 hours. The calcium hydroxide-propolis paste was able to diffuse in dentin.

Assessment of ion diffusion from a calcium hydroxide-propolis paste through dentin.

This study evaluated the ability of ions from a non-alcoholic calcium hydroxide-propolis paste to diffuse through dentinal tubules. Thirty-six single-rooted bovine teeth were used. The tooth crowns were removed, and the root canals were instrumented and divided into 3 groups: Group 1 - calcium hydroxide-propylene glycol paste; Group 2 - calcium hydroxide-saline solution paste; Group 3 - calcium hydroxide-propolis paste. After the root canal dressings were applied, the teeth were sealed and placed in containers with deionized water. The pH of the water was measured after 3, 24, 72 and 168 hours to determine the diffusion of calcium hydroxide ions through the dentinal tubules. All of the pastes studied promoted the diffusion of calcium hydroxide ions through the dentinal tubules. Associating propolis to calcium hydroxide resulted in a pH increase, which occurred with greater intensity after 72 hours. The calcium hydroxide-propolis paste was able to diffuse in dentin.

Effects of intracanal mineral trioxide aggregate and calcium hydroxide during four weeks on pH changes in simulated root surface resorption defects: an in vitro study using matched pairs of human teeth.

INTRODUCTION: Diffusion of hydroxyl ions from intracanal calcium hydroxide (CH) through dentin is used to arrest external inflammatory root resorption. However, long-term and short-term CH placement has been associated with an increased risk of root fracture. Intracanal mineral trioxide aggregate (MTA) might provide an alternative to CH as a source of hydroxyl ions. This in vitro study compared the effects of intracanal MTA and CH on hydroxyl ion diffusion through dentin by measuring pH changes over time in simulated root surface resorption defects prepared in matched pairs of teeth; the null hypothesis tested was that there is no difference. METHODS: Root surface cavities were prepared 5 mm from the apex in extracted human permanent anterior teeth (21 matched pairs) and 7 additional teeth (controls). Root canals were instrumented to size 50/.04 and filled with either tooth-colored MTA (ProRoot) or CH (UltraCal XS); control teeth were filled with saline. The pH in root surface cavities was measured at 3 hours, 24 hours, 1 week, 2 weeks, 3 weeks, and 4 weeks. RESULTS: In controls, pH readings did not differ significantly during the 4 weeks (P > .05, repeated-measures analysis of variance [ANOVA]). For the experimental intragroup effects, significant pH changes occurred over time in the MTA group (P = .005, repeated-measures ANOVA) and the CH group (P < .0001). For the experimental intergroup effects, the overall mean pH was higher in the MTA group (8.66; standard error [SE], 0.07) compared with the CH group (8.46; SE, 0.07) (P = .014, paired t test). At 4 weeks pH was higher in the MTA group (8.30; SE, 0.16) compared with the CH group (7.90; SE, 0.11) (P = .011); at all other time points intergroup differences were insignificant. The null hypothesis was rejected. CONCLUSIONS: Intracanal MTA and CH groups differed in their overall effect on pH measured in simulated root surface resorption defects. At 4 weeks intracanal placement of MTA compared with CH resulted in a small but significantly higher pH.

Evaluation of the diffusion capacity of calcium hydroxide pastes through the dentinal tubules.

This study aimed to evaluate the diffusion capacity of calcium hydroxide pastes with different vehicles through dentinal tubules. The study was conducted on 60 extracted single-rooted human teeth whose crowns had been removed. The root canals were instrumented and divided into 4 groups according to the vehicle of the calcium hydroxide paste: Group I - distilled water; Group II - propylene glycol; Group III - 0.2% chlorhexidine; Group IV - 2% chlorhexidine. After placement of the root canal dressings, the teeth were sealed and placed in flasks containing deionized water. After 1, 2, 7, 15, 30, 45 and 60 days, the pH of the water was measured to determine the diffusion of calcium hydroxide through the dentinal tubules. The data were recorded and statistically compared by the Tukey test. The results showed that all pastes presented a similar diffusion capacity through dentin. Group IV did not present difference compared to group I. Group II presented difference compared to the other groups, as did Group III. In conclusion, groups I and IV presented a better diffusion capacity through dentin than groups II and III; 2% chlorhexidine can be used as a vehicle in calcium hydroxide pastes.

Evaluation of the diffusion capacity of calcium hydroxide pastes through the dentinal tubules

This study aimed to evaluate the diffusion capacity of calcium hydroxide pastes with different vehicles through dentinal tubules. The study was conducted on 60 extracted single-rooted human teeth whose crowns had been removed. The root canals were instrumented and divided into 4 groups according to the vehicle of the calcium hydroxide paste: Group I - distilled water; Group II - propylene glycol; Group III - 0.2 percent chlorhexidine; Group IV - 2 percent chlorhexidine. After placement of the root canal dressings, the teeth were sealed and placed in flasks containing deionized water. After 1, 2, 7, 15, 30, 45 and 60 days, the pH of the water was measured to determine the diffusion of calcium hydroxide through the dentinal tubules. The data were recorded and statistically compared by the Tukey test. The results showed that all pastes presented a similar diffusion capacity through dentin. Group IV did not present difference compared to group I. Group II presented difference compared to the other groups, as did Group III. In conclusion, groups I and IV presented a better diffusion capacity through dentin than groups II and III; 2 percent chlorhexidine can be used as a vehicle in calcium hydroxide pastes.

Evaluación clínica de hidróxido de calcio en la prevención del dolor en dientes permanentes con pulpa necrótica / No disponible

El dolor postoperatorio como resultado de la terapia de conductos es un efecto colateral bastante frecuente en el tratamiento de dientes con pulpa necrótica sin fístula, que puede durar de horas a días, debido en parte a una reacción inflamatoria de la zona peri-radicular. Objetivo. Fue evaluar la eficacia clínica del hidróxido del calcio en la prevención del dolor en dientes permanentes con pulpa necrótica. Material y métodos. Se realizó un estudio en 80 pacientes de 18 a 45 años que requerían tratamiento endodóncico en piezas no vitales sin fístula. Resultados. Se observó que el uso del hidróxido reduce el dolor y la frecuencia de agudizaciones postoperatorias fue relativamente baja. El análisis estadístico realizado consistió en la aplicación de la prueba ji cuadrada (ᵡ2) para independencia en tablas de contingencia ayudados por el software SPSS versión 12. Conclusiones. Se concluye que el hidróxido de calcio como tratamiento en la prevención del dolor postoperatorio en pulpas necróticas sin fístula, no evita la sintomatología postoperatoria ya que existen otros factores que deben ser considerados y aunque son controlados dentro del tratamiento, pueden ser causa de la aparición del dolor entre citas (AU)

Postoperative pain as a result of the root canal therapy is a very frequent side effect in teeth with necrotic pulps without sinus tract that may last a few hours to several days during the endodontic treatment due to the inflammatory reaction in the periradicular area. Objective. The focus of this study was to evaluate the clinical efficacy of calcium hydroxide in preventing postoperative pain in teeth with necrotic pulps. Materials and Methods. Eighty different patients between 18 and 45 years old who required endodontic treatment in non-vital teeth without sinus tract. Results. It was observed that the frequency of postoperative pain exacerbation was relatively low. the statistical analysis was based on the Chi square test (ᵡ2), for the independence in contingency charts. Software SPSS versión 12 was used. Conclusión. This allows us to reach the conclusion that calcium hydroxide used as a treatment to prevent postoperative pain in necrotic pulps without sinus tract does not avoid postoperative symptomatology because there are other factors that should be taken into account and although they are under control within the treatment, it is possible that they influence over the occurrence of interappointment pain (AU)

[Diffusion of hydroxyl ions from calcium hydroxide in the dentinal tubules]. / Etude de la diffusion des ions OH- de l'hydroxyde de calcium dans les tubuli dentinaires.

The aim of this study was to compare hydroxyl ions diffusion from various calcium hydroxide forms: Hycal (1), Roeko points (2) and aqueous suspension placed in the pulpar chamber (3) or in the root canal (4). These experiments were conducted with bovine incisors in order to obtain quantitative evaluation. 540 lateral cavities, deep and superficial, were created in root dentin to measure the hydroxyl ions diffusion with a color indicator, the Blue epsilon With Hycal and aqueous suspension the diffusion of the OH- is obtained in the superficial cavities situated in the coronal part at 14 days (1 = 72%; 3 = 44%; 4 = 100%, (n=18)). In the apical part of the canal this phenomenon is never complete at 21 days (1 = 17%; 3 = 22%; 4 = 17%, (n=18)). No diffusion was observed with the Roeko points (the first generation).

Vehicle influence on calcium hydroxide pastes diffusion in human and bovine teeth.

The purpose of this study was to compare the pH and calcium ion liberation after use of calcium hydroxide pastes with different paste vehicles in human or bovine teeth. Ninety-two single-rooted human and bovine roots were used. The roots were instrumented and an external cavity preparation was performed. The roots were divided in to human and bovine groups. Each group was subdivided into four subgroups (SB) according to the vehicle:SB1, detergent; SB2, saline; SB3, polyethylenoglycol + camphorated paramonochlorophenol (Calen PMCC) and SB4, polyethylenoglycol + furacyn paramonochlorophenol (FPMC). Specimens were immersed into saline solution at 37 degrees C and after 7 and 14 days pH and calcium ion measurements were made. The results were analyzed by anova and Tukey tests (P < 0.05). There was no statistical difference between bovine and human teeth in the pH analysis (P < 0.05), but bovine teeth provided larger calcium ion liberation than human teeth. Calen PMCC was statistically more effective for pH increase and calcium ion liberation in all analyses, followed by FPMC and saline. Detergent showed the lowest pH alterations and calcium ion liberation. The period of 14 days showed more calcium ionic liberation than the 7-day period.

Comportamiento del tejido osteomedular de ratones después de la implantación de mineral trióxido agregado o cemento a base de pasta zinquenólica / Marrow bone reaction of rats after implantation of mineral trioxide aggregate or a zinc-oxide eugenol sealer

El objetivo de este estudio fue evualar las respuestas del tejido osteomedular de ratones a través de la colocación de tubos provistos de mineral trióxido agregado o cemento a base de pasta zinquenólica con adición de agentes radiopacificadores (yodoformo o subnitrato de bismuto) con y sin hidróxido de cálcio. Transcurridos 30, 60 Y 90 días de la implantación, el análisis microscópico y estadístico de los especímenes con los testes Kruskall Wallis y Mann Whitney revelaron que la inflamacion fue más exacerbada en los grupos que presentaban oxido de zinc y eugenol, pero disminuyó con el correr del tiempo, llegando a igualarse a los 60 días, con la inflamación referente al trióxido mineral agregado (MTA) (ps 0,05). Solamente los grupos de MTA y control presentaron neoformación ósea en contacto (ps 0,05). Basandonos en estas observaciones, se puede afirmar que el reparo intraóseo en presencia de MTA es mas rapido que el observado con el o óxido de zinc y eugenol

The marrow bone reaction to mineral trioxide aggregate or a potential zinc-oxide eugenol sealer, added up of radiopaque substances and calcium hydroxide, were studied with using an intraosseous implant technique. The tubes containing the distinct materials were introduced surgically into rat and femur tibias. Control tubes were left empty. After 30, 60 and 90 days, the specimens were histologically processed and microscopically evaluated. The statistical analysis revealed that the MT A cement samples displayed no inflammatory response and direct bone apposition after 30 days, while the response of zincoxide based sealer was characterized by granulation tissue regression and mineralized barrier up to 60 days IpsO.05). Based on these results, repair seems to occur in advance when mineral trioxide aggregate is used

Migration and particle clearance from hard-setting Ca(OH)2 and self-etching adhesive resin following direct pulp capping.

PURPOSE: To evaluate the migration and particle clearance from a hard-setting calcium hydroxide (HSCH) and self-etching adhesive resin (SEAD) following direct pulp capping using the light and electron microscope. METHODS: Exposed monkey pulps were capped with a hard-setting calcium hydroxide (Dycal) or adhesive resin (Clearfil SE Bond), and histopathologically evaluated at 14 and 21 days using light and transmission electron microscopy (n = 14). RESULTS: At 14 days, both HSCH and SEAD materials showed no severe inflammatory reactions of the pulp (necrosis and abscess formation). The main reaction was slight inflammatory cell infiltration consisting of leukocytes. A number of HSCH particles were entrapped by macrophages and observed in the small capillaries similar to blood or lymphatic vessels. For SEAD, slight hemorrhage was observed at the exposed surface. At 21 days, for both HSCH and SEAD, a few cases showed minimal inflammatory response which was limited to the area beneath the exposure. Some macrophages entrapping the HSCH particles in vacuoles within the cytoplasm were arranged at the surface of the capping layer. HSCH particles were also observed in the vessels similar to blood or lymphatic vessels. A few macrophages entrapped filler-like particles of SEAD adjacent to the capping material, but there was no evidence of any SEAD in the vessels.

Eficacia de la solución de hidróxido de calcio a 20% en la reducción de microorganismos asociados a la cárie de dentina / Efficacy of 20% calcium hydroxide solution for reduction of microorganisms in carious dentin

Objetivo: Evaluar la eficacia de la solución de hidróxido de calcio a 20% en la reducción de microorganismos asociados a la carie de dentina. Metodología: Treinta preparos cavitários fueron realizados en molares permanentes de 30 individuos entre las edades de 9 a 18 años. Solución salina reductora fue utilizada como líquido de colecta para la recuperación de microorganismos, antes y después del lavado cavitário. Las muestras fueron colocadas en placas de agar sangre de carnero e incubadas en anaerobiosis por 48 horas a 37°C. Después del crecimiento bacteriano, se realizo un análisis semi cuantitativo y cualitativo de las bacterias, a través de hibridización DNA-DNA para 23 tipos de bacterias. Resultados: una reducción significativa de la cantidad de microorganismos en las muestras colectadas después del lavado de la cavidad con solución de hidróxido de calcio fue observada cuando comparado con el momento anterior al lavado. Del total de muestras que presentaron microorganismos en la cavidad recién preparada, 46,15% presentaron eliminación de éstos microorganismos después del lavado con agua de cal y 53,84% presentaron reducción significativa del número de microorganismos. El teste t pareado de Student mostró una diferencia extremamente significativa (p=0,0007) entre el momento anterior y posterior al lavado. Con relación al tipo de bacterias encontradas después Del lavado de la cavidad con solución de hidróxido de calcio, se observó reducción considerable de S. anginosus, S. mitis y S. sobrinus, así como de S. aureus y S. epidermidis, a pesar de no ser significativa (p>0,05).Conclusión: La solución de hidróxido de calcio parece ser un método de limpieza cavitária eficaz en la reducción de la microbiota asociada a la carie de dentina (AU)

Objective: This study aimed to test the effectiveness of the cavity cleansing solution (calcium hydroxide 20%) in the elimination or reduction of microorganisms associated to dentine caries. Materials and methods: Thirty cavities preparations were made in permanent molars of individuals aging 9-18. A saline solution was used as sampling liquid before and after the cavity washing. The samples were sown in blood agar plates and incubated in anaerobiosis for 48 hours at 37ºC. After the bacterial growth, a quantitative and qualitative analysis of the bacteria was accomplished trough the use of DNA-DNA hybridization for the 23 bacteria. Results: A significant reduction of the amount of microorganisms of the samples collected after laundering was observed when compared with the previous laundering moment (p=0,0007). Of the total of samples that presented microorganisms in the recent prepared cavity, 46,15% had gotten total elimination and 53,84% had presented significant reduction of microorganisms. In relation to the bacteria found after the contaminated tissue removal and washing with calcium hydroxide solution, considerable reduction was observed for S. anginosus, S. mitis and S. sobrinus, as well as for S. aureus and S. epidermidis, although it is not significant ( p>0,05). Conclusion: The calcium hydroxide solution seems to be efficient in the reduction of the microbiota associated to dentine caries and, therefore, recommended for use in the clinical practice to support the cavity preparation aiming recurrent caries reduction (AU)

Apical diffusion of calcium hydroxide in an in vitro model.

An in vitro agar model was developed to study the effect of intracanal medicaments on periapical tissues and was used to study the diffusion of three calcium hydroxide (Ca(OH)2) medicaments of varying viscosity through simulated root canals with various sizes of apical foramina. Experimental medicaments were added to pipette tips used to represent tooth roots, which were fixed in syringes containing brain heart infusion agar and calcium-reactive dye. OH and Ca concentrations were measured in the agar at 30 minutes and 24 hours. Ca concentration and pH increased with larger aperture sizes, and higher pH and Ca diffusion was produced by a 10% Ca(OH)2 solution than was produced by Pulpdent or a Ca(OH)2 paste. The results suggest that the properties of the Ca(OH)2-containing vehicle could affect the action of the medicament in the periapical tissues.

Ca2+ diffusion through dentin of Ca(OH)2 associated with seven different vehicles.

This investigation measured the diffusion of Ca2+ through dentin by using Ca(OH)2 associated with various vehicles. After mechanical preparation and removal of smear layer, 41 human premolar teeth were stored individually in flasks containing 800 ml of ultra-pure deionized water for 2855 h. The Ca2+ concentration was measured by atomic absorption spectrophotometry as a function of time. These measurements were divided into two phases: dissolution, to check the loss of Ca2+ from the tooth structure itself, for which all canals were kept empty and open in the absence of medication for 1168 h, and diffusion, in which the specimens were divided into 10 groups (3 control groups: group 1 = water control, group 2 = sealing control, and group 3 = open canal dissolution control; 7 experimental groups in which the whose canals were filled with Ca(OH)2 paste associated with the following vehicles: group 4 = saline; group 5 = polyethylene glycol (Calen); group 6 = glycerin and camphorated parachlorophenol group 7 = camphorated paramonochlorophenol; group 8 = glycerin; group 9 = glycerin and tricresol formaldehyde (TCF); and group 10 = anesthetic solution. This phase lasted 1687 h. A total of 1058 measurements of Ca2+ were made. Regression analysis was used for statistical evaluation. We concluded that diffusion occurred differently for each group: the medications used in the root canals interacted with the dentinal structure or among themselves; the medication coated the dentinal tubule, facilitating the diffusion of Ca2+ into the external part of the root.

Reação do tecido conjuntivo subcutâneo de rato ao MTA e ao hidróxido de cálcio / Reaction of rat connective tissue to implanted Mineral Trioxide Aggregate (MTA) and to calcium hydroxide

Foram analisadas as reações que ocorrem no tecido conjuntivo de ratos em contato com tubos de polietileno, contendo agregado de trióxido mineral (MTA) e uma pasta de hidróxido de cálcio (Calen). Os animais foram sacrificados nos períodos de 7, 14 e 30 dias. A maioria dos espécimes foram corados com hematoxilina e eosina, os demais com a técnica de Von Kossa para tecidos mineralizados. Próximo às aberturas do tubo foi constatada a presença de insenso infiltrado inflamatório, que no período de 30 dias de apresentou leve. Foi observada tanto junto ao agregado de trióxido mineral como junto à pasta de hidróxido de cálcio (Calen), a formação de uma cápsula fibrosa fina. Nos espécimes tratados pela técnica de Von Kossa somente foram encontradas áreas positivas nos que continham hidróxido de cálcio (Calen)

Sealer distribution in coronal dentin.

A major cause of tooth discoloration is sealer remnants in the pulp chamber after root canal treatment. The purpose of this study was to assess coronal distribution and color changes of four commonly used sealers placed in the pulp chamber after 2 yr. Fifty extracted premolars were cross-sectioned in the coronal third of the root. The chamber contents were removed, and instrumentation was via the canal; then freshly mixed sealer was placed in each chamber. Sealers evaluated were: AH 26, Kerr Pulp Canal Sealer, Roth 801, and Sealapex. The apical access was sealed with white sticky wax, and the tooth was maintained in a moist environment at 37 degrees C for 2 yr. Teeth were split longitudinally, and digital images of the exposed dentin were made, scrambled, and evaluated blindly by trained evaluators for color changes and for presence of sealer in dentin. There was no measurable penetration of sealer into dentin for all groups and no dentin discoloration occurred. The sealers displayed marked discoloration. At 2 yr, the sealers discolored and remained confined primarily to the pulp chamber.