Dentinal tubule penetration of endodontic sealers after nonthermal plasma treatment: A confocal laser scanning microscopy study.

One of the factors affecting the success of endodontic treatment is to fill the root canal system hermetically. The aim of this in vitro study was to evaluate the effect of nonthermal plasma (NP) on dentinal tubule penetration of root canal sealers using confocal laser scanning microscopy. Forty mandibular premolar teeth were selected and the root canals were prepared with large-Waveone-Gold rotary-files. Specimens were divided into four experimental groups according to sealer and NP treatment (n = 10). G1: AH-Plus (AH) G2: nonthermal plasma application + AH-Plus(AH-P) G3: Endosequence-BC(BC) G4: nonthermal plasma application + Endosequence-BC(BC-P). Cold lateral-condensation technique was used for the obturation of root canals. The roots were sectioned horizontally and the sections were examined under confocal laser scanning microscopy. The maximum tubule penetration and percentage of penetration values were obtained from the microscopy images and were statistically analyzed with repeated measurements-ANOVA and the Tukey (HSD) test (p < 0.05). The percentages of dentinal tubule penetration of the groups were not statistically different. The maximum tubule penetration of the AH-P was statistically lower than that of the BC-P (p < 0.05). Plasma application had no affect on the percentage of dentinal tubule penetration. Under the conditions of this in vitro Endosequence-BC sealer showed higher maximum tubule penetration values than AH-Plus after NP treatment. Percentage of dentinal tubule penetration values of experimental groups was similar.

Fluoride release and recharging ability of new dental sealants.

AIM: This in vitro investigation was to evaluate the fluoride release and recharge abilities of three recently introduced dental fissure sealants (FS). METHODS: Three dental FS were assessed: Teethmate F-1 (Kuraray), Fissurit F (Voco), BeautiSealant (Shofu), and a conventional glass ionomer cement FX-II (Shofu) as a control. Eight cylindrical specimens (7 × 2 mm) of each material were made and immersed individually in 5 ml de-ionized water in plastic containers. Fluoride release of the tested materials was evaluated during the experimental period (28 days) utilising a fluoride ion-selective electrode. At the end of the test period, the specimens were soaked for 5 min in a fluoride solution (0.05 % NaF) and fluoride release was evaluated for the next 5 days. The data were statistically analysed using one-way ANOVA and Bonferroni post hoc test and the level of significance was preset at α = 0.05. RESULTS: The total fluoride release over the 28-day period for each material was: FX-II (408.6 ± 45.66 µg/cm(2)) > Teethmate F-1 (89.45 ± 12.32 µg/cm(2)) > Fissurit F (68.62 ± 8.72 µg/cm(2)) > BeautiSealant (33.32 ± 4.91 µg/cm(2)), (p < 0.05). After the re-fluoridation of the specimens with 0.05 % NaF solution the cumulative fluoride re-release during the 5-day period for each material was: FX-II (99.53 ± 13.21 µg/cm(2)) > Teethmate F-1 (9.76 ± 1.62 µg/cm(2)) > BeautiSealant (5.69 ± 0.89 µg/cm(2)) > Fissurit F (4.76 ± 0.72 µg/cm(2)), (p < 0.05). CONCLUSIONS: The three tested sealants exhibited different capabilities to release and uptake fluoride ions after re-fluoridation but significantly lower than the glass ionomer tested.

Evaluación de la efectividad del MTA como tapón cervical en el blaqueamiento de dientes tratados endodónticamente / Evaluation of the effectiveness of MTA as a barrier for bleaching of endodontically treated teeth

Objetivo. Fue evaluar la capacidad selladora en la infiltración de colorante en barreras cervicales, utilizadas en el blanqueamiento de dientes tratados endodónticamente, utilizando materiales anteriormente estudiados y el MTA. Material y método. Fueron utilizados 40 dientes extraídos, divididos en 4 grupos, fue realizada la técnica de walking bleach, utilizando como agente blanqueador peróxido de digrogeno asociado al perborato de sodio y un agente trazador (azul de metileno). Después de realizar el tapón cervical con los diferentes materiales manipulados (fosfato de zinc, ionómero de vidrio y la gutapercha asociada al cemento obturador y un paquímetro e inspección visual por 3 examinadores previamente calibrados. Resultados. El MTA presentó menos infiltración que el resto de los materiales utilizados como tapón sin obtener diferencia estadísticamente significante (P=0,154). Conclusiones. El MTA demostró menor infiltración del colorante sobre los demás materiales. Por lo tanto en el análisis de marcadores, el resultado estadístico no fue significante; y en la evaluación, donde fue medida la infiltración lineal de colorante, se obtuvo un resultado significativo del grupo del MTA sobre el grupo control, que fue el de gutapercha asociado al cemento obturador (AU)

Objective. To evaluate the sealing ability of cervical barriers used in whitening teeth treated endodonically, using materials previously studied and the MTA peroxide and sodium perborate associated with a tracer agent (methylene blue). After perfoming the cervical buffer with different materials (zinc phosphate, glass ionomer, gutta-percha associated with cement and MTA) the bleaching agent was used. Next the teeth were sectioned longitudinally to assess the infiltration linear and measure with a pachymetry. Visual inspection was performed by three previously calibrated examiners. Results. The MTA had less infiltration than other materials used as a buffer, without obtaining statistically significant difference (P=0.154). Conclusions. The MTA showed less infiltration of dye than other materials. Therefore in the marker analysis, the result was not statistically significant, and in the evaluation, which was measure by linear infiltration of the dye, we obtained a significant result of the MTA group over the control group, which was gutta- percha associated with a cement (AU)

Penetration of experimental infiltrants with different penetration coefficients and ethanol addition into natural caries lesions in primary molars.

This study evaluated the influence of the penetration coefficient (PC) and ethanol addition on the penetration depth (PD) of experimental infiltrants into proximal caries lesions in primary molars. Caries lesions (n = 45) were randomly treated with 1 of 4 experimental infiltrants (PC63; PC185; PC204; PC391) for 5 min. Lesion depths and PDs were analysed using dual fluorescence confocal microscopy. Lesions were almost completely infiltrated in all groups. Median PDs and percentage penetrations were not significantly different between groups (p > 0.05). When applied for 5 min, all tested infiltrants were able to infiltrate proximal caries in primary molars nearly completely.

Effect of alkaline ph on sealing ability of white mineral trioxide aggregate

Objectives: The aim of this study was to evaluate microleakage of white mineral trioxide aggregate (WMTA) after its exposure to a range of alkaline environments during hydration.Study Design: Seventy single-rooted teeth were divided into 4 experimental and 2 control groups. All the teeth were instrumented, and their apices were resected. Root-end cavities were filled with WMTA in the experimental groups. In the control groups, root-end cavities were not filled. Root-end fillings were exposed to alkaline environments with pH values of 7.4, 8.4, 9.4, or 10.4 for 3 days. Microleakage was evaluated by bovine serum albumin.Evaluations were carried out at 24-hour intervals for 80 days. Data were analyzed by one-way analysis of variance and a post hoc Tukey test at the 0.05 level of confidence.Results: The number of days (mean ± standard deviation) needed for color change at pH values of 7.4, 8.4, 9.4, and10.4 were 78.53 ± 5.68, 80.00 ± 0.00, 68.93 ± 19.00, and 34.46 ± 12.73, respectively. The time needed for leakageto occur was significantly shorter in samples stored at a pH value of 10.4 (P<0.001).Conclusions: Within the limits of this study, it can be concluded that pH values greater than 9.4 may jeopardizethe sealing ability of WMTA during hydration (AU)

Microleakage comparison of glass-ionomer and white mineral trioxideaggregate used as a coronal barrier in nonvital bleaching

Objectives: There is some evidence that the pH at the root surface is reduced by intracoronal placement of bleaching pastes, which is known to enhance osteoclastic activity. Therefore, it is recommended that a protective barrierbe used over the canal filling to prevent leak age of bleaching agents. Glass-ionomer (GI) is commonly used asa coronal barrier before nonvital bleaching. Because mineral trioxide aggregate (MTA) creates high alkalinityafter mixing with water, using MTA as a protective barrier over the canal filling may not only prevent leakage of bleaching agents and microorganisms, but may prevent cervical resorption. The aim of this study was to evaluates ealing ability of white mineral trioxide aggregate (WMTA) as a coronal barrier before nonvital bleaching.Study design: Root canals of one hundred thirty human maxillary incisors were instrumented and filled withgutta-percha without sealer. Gutta-percha was removed up to 3 mm below the cementoenamel junction (CEJ). Theteeth were randomly divided into six experimental groups of 20 teeth each and two control groups of 5. In three experimental groups, WMTA was packed into the canal to the level of CEJ. In the remaining experimental groups,glass-ionomer (GI) was used as a coronal barrier. After a 24-hour incubation period, one of the following threebleaching agents was placed in the access cavity of each of the WMTA or GI groups. These three bleaching agentswere 30% hydrogen peroxide, sodium perborate mixed with 30% hydrogen peroxide, and sodium perborate mixedwith distilled water. The bleaching agents were replaced every 3 days for three times. In the positive controls, no (..) (AU)

An in vitro evaluation of two dentine adhesive systems to seal the pulpchamber using a glucose penetration model

Objectives: To evaluate the sealing capability of Cavit™ G with or without Clearfil™ S3 Bond and Prime & BondNT placed in the pulp chamber.Study Design: Forty single rooted premolars, extracted for orthodontic and periodontal reasons, with intact coronalsurface and mature apices, were standardized to a length of 15 mm. The teeth were instrumented, filled witha gutta-percha master cone and divided into three groups to obturate the pulp chambers: Cavit™ G; Clearfil™S3 Bond plus Cavit™ G and Prime & Bond® NT plus Cavit™ G. A glucose leakage model was used for evaluatingthe coronal microleakage. The Mann-Whitney test was used to evaluate the differences in the means of theglucose leakage.Results: An increase in glucose penetration was observed during the first week in groups Cavit™ G and Cavit™G+PBNT. The glucose penetration values of all groups were similar at 30 and 45 days, and there were no significantdifferences among them in both time periods (p=0.736 and p=0.581, respectively).Conclusions: The adhesive systems did not improve the capability of Cavit™ G to seal the pulp chamber overtime (AU)

An in vitro comparison of different adhesive strategies on the micropush-out bond strength of a glass fiber post

Objectives: To evaluate in vitro the push-out bond strengths of a glass fiber post adhesively luted with self-etchingresin based and self-adhesive luting cements, as well as modified application procedure of self-adhesive lutingcements in combination with single step self-etch adhesives.Materials and methods: Fifty single-rooted human maxillary central incisor teeth were endodontically treated anddivided into five groups (n=10). Glass fiber posts (RelyX Fiber Post) were cemented with the following materials:group 1: ED Primer II/Panavia F 2.0 (PAN); group 2: RelyX Unicem (RU); group 3: Maxcem (MC); group 4:Adper Prompt L-Pop (PLP)/RelyX Unicem; group 5: Optibond all-in-one (OB)/Maxcem. Bonded specimens werecut (1-mm-thick sections) and push-out tests were performed (crosshead-speed, 0.5 mm/min). Data were analyzedby one-way ANOVA followed by the Tukey-HSD test for post hoc comparisons at á = 0.05.Results: The highest bond strength was recorded for groups 4 and 2, with no statistically significant differencesamong them (p>0.05). Group 4 showed significantly higher bond strength than group 1 (p<0.001), group 3(p<0.0001) and group 5 (p<0.0001). Group 1 showed significantly higher bond strength than the group 3 (p<0.05).No statistically significant differences were observed among group 1 and group 2, group 1 and group 5, group 3and group 5. Group 3 showed significantly lower push-out bond strength than the all other luting strategies exceptfor the group 5.Conclusions: The push-out bond strength values of modified application procedure of self-adhesive luting cements(RU and MC) in combination with single step self-etch dentin adhesives (PLP and OB) did not improve the pushoutbond strength of fiber post when compared with those where the conventional use of self-adhesive cements (AU)

Microbial leakage of MTA, Portland cement, Sealapexand zinc oxide-eugenol as root-end filling materials

Objective: The aim of this study was to compare the microbial leakage of mineral trioxide aggregate (MTA), Portlandcement (PC), Sealapex and zinc oxide-eugenol (ZOE) as root-end filling materials.Study design: An in vitro microbial leakage test (MLT) with a split chamber was used in this study. A mixtureof facultative bacteria and one yeast (S. aureus + E. faecalis + P. aeruginosa + B. subtilis + C. albicans) wasplaced in the upper chamber and it could only reach the lower chamber containing Brain Heart Infusion broth byway of leakage through the root-end filling. Microbial leakage was observed daily for 60 days. Sixty maxillaryanterior human teeth were randomly assigned to different groups - MTA and PC (gray and white), Sealapex + zincoxide and ZOE, control groups and subgroups to evaluate the influence of EDTA for smear layer removal. Thesematerials were further evaluated by an agar diffusion test (ADT) to verify their antimicrobial efficacy. Data wereanalyzed statistically by Kruskal-Wallis and Mann-Whitney test.Results: In the MLT, Sealapex + zinc oxide and ZOE did not show evidence of microbial leakage over the 60-dayexperimental period. The other materials showed leakage from the 15th day. The presence of smear layer influencedmicrobial leakage. Microbial inhibition zones were not observed in all samples tested by ADT.Conclusion: Sealapex + zinc oxide and ZOE did not show microbial leakage over the experimental period, whereasit was verified within 15 to 45 days in MTA and Portland cement (AU)

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Bisphenol A blood and saliva levels prior to and after dental sealant placement in adults.

PURPOSE: This study examined the effects of a widely used (Delton Pit & Fissure Sealant - Light Cure Opaque, DENTSPLY Professional, York, PA) pit and fissure sealant material on bisphenol A (BPA) levels in blood and saliva, among both low and high-dose groups over time. METHODS: A convenience sample of 30 adults from the Old Dominion University population were randomly and evenly divided into 2 independent variable groups: a low-dose group (1 occlusal sealant application) and high-dose group (4 occlusal sealant applications). A 2 group, time series design was used to examine the presence and concentration of BPA in serum and saliva after sealant placement. Differences comparing low-dose and high-dose groups were examined 1 hour prior (baseline), 1 hour post, 3 hours post and 24 hours after sealant placement, as measured by a direct-competitive BPA Enzyme Linked ImmunoSorbent Assay (ELISA). Hypothesized outcomes were evaluated by applying a parametric, 2 way ANOVA for repeated measures technique to data on the 30 participants ranging in age from 18 to 40 years, and were of mixed gender and ethnicity. RESULTS: BPA was detected in the saliva of all participants prior to sealant placement and ranged from 0.07 to 6.00 ng/ml at baseline. Salivary BPA concentration levels peaked over a 3 hour period following sealant placement and returned to baseline levels within 24 hours. BPA was significantly elevated at all post-sealant placement time periods for both the low-dose (1 occlusal sealant application) and high-dose (4 occlusal sealant applications) groups with peak levels of 3.98 ng/ml and 9.08 ng/ml, respectively. The blood serum did not contain BPA at any point in this investigation. CONCLUSIONS: Exposure to BPA from sources other than dental resins contributes to salivary baseline concentration levels and indicates environmental exposure and use of products containing BPA. Use of specific molecular formulations of dental sealant material determines the release of BPA, therefore, dental sealant materials should be reviewed independently when questioning the release of BPA from dental sealants. In addition, dosage amounts of the dental sealant material used in this study do not influence the serum concentration levels of BPA. Further research is needed to examine the cumulative estrogenic effects of BPA from dental sealants.

Reacción del tejido conectivo de ratas a dos selladores endodónticos a base de resinas / Reaction of the rat conective tissue by two base don resin endodontic sealer

El propósito de este estudio fue evaluar la respuesta del tejido conectivo de ratas, ante dos selladores endodónticos a base resinas, el Abseal de la firma Meta Biomed Co Corea y AH36 de la firma De Trey/Dnstply-Maillefer EE.UU. Se utilizaron 40 ratas Wistar hembras de aproximadamente 150-200gr de peso. Los materiales fueron llevados en tubos de silicona e implantados en tejido celular subcutáneo de ratas. Para el control negativo se utilizaron tubos vacíos. Los animales fueron sacrificados en grupos de 10 a lso 7, 14,30 y 60 días. Se evaluó cualitativa y cuantitativamente la reacción inflamatoria producida por los implantes bajo microscopia óptica. Los resultados mostraron que el área de reacción inflamatoria en los tubos obturados con Adseal fue menor en los controles de 7,14 y 30 días. A los 60 días ambos materiales mostraron aéreas mínimas de inflación (AU)

The aim or this study was to evaluate the inflammatory reaction of the connective tissue of rats produced by two resin based endodontic sealers: Adseal (MetaBiomed Korea) and AH26 (De Trey/Densply-Zurich). For this study two groups of forty Wstar rats, 150-200 grams body weight, were employed. Silicons tubes were filled with the sealers and implanted in cellular subcutaneous tissue in rats. Emply tubes were used as negative control. They were then sacrified in groups of ten edach at 7, 14.30 and 60 days. The inflammatory reaction qualitative and quantitative was evaluated under optic microscopy. The results showed smaller inflammatory areas around Adseal tubes at 7,14, and 30 days. On the 60 days tests both materials showed minimal inflammatory areas (AU)

A comparative study of silver amalgam and compomer as retrograde filling materials in periapical surgery

Objective: A comparative study is made of the histological effects of silver amalgam versus compomer (Dyract®) 90 days after placement as retrograde filling materials in experimental animals.Method: Six Beagle dogs were used, with total pulpectomy and orthograde material filling followed by periapicalsurgery of the 6 upper and 6 lower incisors (for a total of 72 teeth). Thirty-six teeth corresponded to the right side and were filled with the control material (silver amalgam), while the 36 teeth on the left side were filled with the compomer study material (Dyract®). After three months the animals were sacrificed and the histological study was carried out, with evaluation of bone formation, inflammation, and the tissue in contact with the filler material. The results obtained were subjected to a descriptive and comparative statistical analysis (chi-square test).Results: The samples retrogradely filled with compomer showed significantly greater percentage inflammation (76.19% versus 26.66% in the control group). On the other hand, a large proportion of samples with root cement growth were found in the compomer group. Filler material expulsion was also significantly more common when compomer was used.Conclusions: the comparative study of the histological findings showed greater inflammation but also greater root cement growth in the compomer group versus the controls (AU)

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Retention of three fissure sealants and a dentin bonding system used as fissure sealant in caries prevention: 12-month follow-up results

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Background. Bonding agents could be used as fissure sealants. This study compares the retention three fissure sealants (Delton®, Delton Plus® and Concise®) and a filled dentin bonding system (Optibond Solo®).Methods. Fifty-six children aged 7-8 years received fissure sealants either in the four permanent first molars, in the four deciduous second molars, or in all eight of these teeth. Every child received a different sealing material in each quadrant on a random basis. Clinical evaluation at 12 months was performed by a single blind examiner, and the retention was classified as either a success (total retention) or a failure (partial retention or not present).Results: There were no statistically significant differences among the four materials in permanent maxillary molars ordeciduous molars. In permanent mandibular molars, Optibond Solo® showed a lower percentage of retention (40.9%),significantly different (p=0.002) to that of Delton® (89.5%), Delton Plus® (87.5%) and Concise® (76.5%).Conclusion: One bottle dentin bonding system used as a sealant does not improve the retention of conventional fissuresealants.Clinical Implication: Because of the scarcity of studies on the use of dental adhesives as sealants, further studies are warranted for the final support of that conclusion

Tratamiento de perforaciones radiculares en dientes de perros con dos marcas comerciales de agregado trióxido mineral (MTA) / Root perforations treatment in dog´s teeth with two agregate mineral trioxide (MTA)

El propósito de este trabajo fue evaluar la respuesta de los tejidos periodontales interradiculares de dientes de perros, perforados y sellados inmediatamente con ProRoot MTA y MTA-Angelus. Concluido el tratamiento de conductos radiculares, se realizaron en cada diente perforaciones en la raíz mesial, a nivel de la entrada del conducto radicular, en dirección de la furca. 90 días después los perros fueron sacrificados por perfusión y las muestras procesadas para estudio microscópico. Los resultados mostraron neoformación de tejido mineralizado, sellando totalmente la perforación en todos los casos y mínima inflamación de tipo crónico, consecuente del extravasamiento de material sellador. La prueba no paramétrica de Kruskal-Wallis demostró no existir diferencia estadísticamente significante entre ambos materiales. El ProRoot MTA y el MTA-Angelusson materiales con adecuadas propiedades biológicas y crean las condiciones ideales para que ocurra la reparación de los tejidos periodontales interradiculares en dientes de perros

The purpose of this work was to evaluate tbe response of the periodontal tissue of dogs' teeth which was perforated and sealed immediately witb ProRootMTA and MTA-Angelus. Concluded the treatment of root canals, they were carried out in each tooth perforations in the root mesial, at level of the entrance of the root canal, in direction of the furca. 90 days later the dogs were sacrificed by perfusionand processed for microscopic study. The results showed neoformation of tissue mineralized sealing the perforation totally in all the cases and mínimum inflammation of chronic type, consequent of the extravasation of sealer material. The non parametric test of Kruskal Wallis demonstrated not to exist differs statistically significant between both materials. The ProRoot MTA and tbe MTA-Angelus are material with appropriate biological properties and believe the ideal conditions so that it happens the repair of the periodontal tissue in dogs'teeth

[The penetration of various adhesives into early enamel lesions in vitro]. / Penetration verschiedener Adhäsive in initiale Schmelzläsionen in vitro.

The aim of the present study was to evaluate the penetration depth (PD) and the thickness of the oxygen inhibition layer (OIL) of a fissure sealant (Helioseal, Vivadent) and various adhesives (Heliobond, Excite, Vivadent; Resulcin, Merz; Solobond M, Voco; Prompt L-Pop, 3M-Espe) applied to enamel lesions in vitro. From 27 bovine teeth 54 enamel specimens were prepared and covered with nail varnish (control) thus obtaining three windows for treatment. After demineralisation (pH 5.0, 14 d) two of the windows were etched with phosphoric acid (20%, 5 s), whereas the third area served as control. The specimens were divided randomly into six groups (n = 9) and the respective adhesive was applied (90 s), either once or twice. Light-curing followed each application. Enamel slabs (perpendicular to the surface) were cut and studied after infiltration with a fluorescent low-viscous resin using confocal microscopy (CLSM). The image of the lesion was divided into two areas with different grey values. Lesion depths were calculated (ImageJ) from the surface to that point in the lesion where the grey value clearly changed to a darker grey value. The zone with the darker grey values marked the front of demineralisation. Mean lesion depths (+/- SD) after demineralisation were measured at 105 (+/- 21) microm. After single application, Resulcin [89 (+/- 22)%] and Helioseal [98 (+/- 6)%] had almost completely penetrated the lesion. Heliobond [126 (+/- 33)%] and Excite [184 (+/- 40)%] penetrated even deeper than the defined lesion. For Excite double application decreased the OIL significantly (p = 0.03; adjusted paired t-test). Adhesives are capable to penetrate artificial initial enamel lesions completely. Follow-up studies are needed to confirm this effect for natural lesions.

[Release of fluoride ions into saliva from some dental materials]. / Uwalnianie jonów fluorkowych do sliny z wybranych materialów stomatologicznych.

The aim of the study was to evaluate fluoride release from dental materials: resin composites--Tetric Ceram and Degufill Mineral, fissure sealants--Conseal F and Admira seal, compomer--Freedom and glass-ionomer cement--Vitremer. Release to the patient's unstimulated mixed saliva was studied after treatment with the material. The study group comprised 72 patients and fluoride concentrations were measured with an ion-selective electrode (Orion). The following release of fluoride in decreasing order was found: Vitremer (6.03 microM), Degufill Mineral (2.79 microM), Teric Ceram (2.54 microM), Freedom (2.52 microM), Admira seal (1.85 microM) and Conseal F (1.80 microM).

[Effect in vitro of environmental parameters on the release of fluoride ions from some materials used in dentistry]. / Wplyw parametrów srodowiska na uwalnianie jonów fluorkowych z wybranych materialów stomatologicznych--badania in vitro.

The aim of this in vitro study was to evaluate the influence of calcium ions and pH on fluoride release from selected dental materials. The materials studied included a resin composite (Te-Econom), fissure sealant (Conseal F) and compomer (Freedom). Samples were placed for 7 days in artificial saliva with or without calcium ions and pH ranging from 4.5 to 7.5. Fluoride release from the studied materials was measured with an ion-selective electrode (Orion). The results demonstrate differing effects of calcium concentration and pH on fluoride release. The highest cumulative fluoride release was observed from Freedom and the lowest from Te-Econom. Addition of calcium ions to the medium reduced the release of fluoride.

Determination of bisphenol A and related aromatic compounds released from bis-GMA-based composites and sealants by high performance liquid chromatography.

Most of the composites and sealants used in dentistry are based on bisphenol A diglycidylether methacrylate (Bis-GMA). Reports revealed that in situ polymerization is not complete and that free monomers can be detected by different analytic methods. Concerns about the estrogenicity of bisphenol A (BPA) and other aromatic components leached from commercial products have been expressed. We studied biphenolic components eluted from seven composites and one sealant before and after in vitro polymerization using HPLC and gas chromatography/mass spectrometry and we investigated how pH modifications affect the leaching of these components. We found BPA (maximal amount 1.8 microg/mg dental material), its dimethacrylate derivative (Bis-DMA, 1.15 microg/mg), bisphenol A diglycidylether (6. 1 microg/mg), Bis-GMA (2.0 microg/mg), and ethoxylate and propoxylate of bisphenol A in media in which samples of different commercial products were maintained under controlled pH and temperature conditions. Our results confirm the leaching of estrogenic monomers into the environment by Bis-GMA-based composites and sealants in concentrations at which biologic effects have been demonstrated in in vivo experimental models. The main issue with implications for patient care and dentist responsibility is to further determine the clinical relevance of this estrogenic exposure.

Use of fluoride-containing sealant on proximal surfaces.

A visible light curing sealant was developed for the prevention of caries on the smooth surfaces especially on the proximal surfaces. The sealant is mainly composed of dimethacrylate monomers. It contains a total amount of 2.28 mass% fluoride as poly(methyl methacrylate-co-methacryloyl fluoride) and sodium fluoride. The fluoride-containing sealant could be successfully applied to the proximal surfaces between the first and second primary molars by making access to the interproximal space with an orthodontic separating module. Availability of fluoride was assessed by the concentration of fluoride released into 1 ml of distilled water as a function of time from disks 5 mm in diameter and 0.2 mm in thickness. Ten microg of fluoride was measured on the first day; after 3 days the rate remained fairly constant at about 1 pg/day for a period of 28 days. The fluoride uptake and the improved acid solubility were investigated in vitro using bovine incisors. The fluoride of the control, that is enamel without sealant treatment, was not detectable. The fluoride incorporated into enamel after 37 hours application was 2,100 ppm at 2 pm from the enamel surface. The enamel solubility to acids decreased by the fluoride incorporation.

Extractable free monomers from self-cured dental sealants resulting from dispensing errors.

High performance liquid chromatography (HPLC) experiments were performed on a series of commercially available self-curing dental sealant materials that were deliberately mismixed. The goal of the experiments was to measure the amount of extractable sealant under conditions of nonideal processing as might happen clinically. The stoichiometry of the two component resins ranged from a 2/1 to a 1/2 catalyst to base mixture using a commercially available self-cure sealant that was to be mixed 1/1 based on the manufacturer's recommendations. Following fabrication the samples were immersed in an ethanol/water mixture as an extraction fluid that was then analyzed using HPLC. Values other than the 1-1 stoichiometry led to a statistically larger extractable content of bis-glycidyl methacrylate relative to the control. The extractable fraction of triethylene glycol dimethacrylate also increased with mismixing, although statistical differences varied somewhat more. Given the increased concerns about the effects of extractable monomers on the endocrine system, there may be an increased need to maintain proper stoichiometry in a clinical setting.