Magister Chirurgiae Dentium (MChD) / A review of current root canal obturating materials and obturation techniques was undertaken. This was prompted by the wide variety of the materials and techniques currently being used in the Western Cape. A questionnaire was circulated to 320 members of the Cape (Western) Branch of the D.A.S.A. A viable return of 54,43% was received and this data was studied to determine the pattern of usage of the different materials and techniques in the sample area. Gutta- percha proved to be the mo~t popular obturating material (64,4X) and the gutta-percha lateral condensation technique was indicated by 32,7% of the respondents as being used by them. The cement sealer employed by most respondents was Endométhasone .(38,2%), followed by Riebler's paste (17,3%) and zinc oxide-eugenol (12,5%). This is contrary to the current teaching at the Dental Faculty of the University of Stellenbosch. An extensive review of the literature on obturating mater ials and techniques was undertaken with consideration to the composition and the physical, chemical and sealing properties of the materials being gi ven. Adverse tissue reacti ons caused by the different materials were reviewed as were any peculiarities of the root canal obturation technique. The expected success or failure rates of relevant techniques were considered as well as their advantages and disadvantages. In conclusion certain recommendations as to viable changes to the present endodontic curriculum of the Dental Faculty, University of Stellenbosch are made, based on information revealed by this study.

<p>U slučajevima neuspe&scaron;ne endodontske terapije, neophodno je ponovno lečenje kanala korena. Ortogradni endodontski retretman podrazumeva uklanjanje postojećeg materijala za punjenje iz kanala uz dodatno či&scaron;ćenje, dezinfekciju i ponovnu finalnu opturaciju kanala. Važan korak u toku retretmana je &scaron;to potpunije uklanjanje postojećeg kanalnog punjenja kako bi se pristupilo svim delovima kanalnog sistema. Cilj doktorske teze bio je da se ispita kvalitet čis&scaron;ćenja zidova kanala korena nakon endodontskog retretmana pomoću skening elektronske mikroskopije (SEM). Posmatran je uticaj vrste materijala za opturaciju, uticaj upotrebe rastvarača i uticaj ručnih i ma&scaron;inskih instrumenata na količinu zaostalog materijala na zidovima kanala. Takođe, ispitan je uticaj ovih faktora na apikalnu transportaciju materijala i na vreme potrebno za retretman, a utvrđena je i učestalost o&scaron;tećenja kori&scaron;ćenih instrumenata. Materijal i metode: Ukupan uzorak činilo je 125 ekstrahovanih, humanih jednokorenih zuba. Nakon preparacije kanala korena, 120 zuba je podeljeno u dve grupe i napunjeno pomoću dva različita materijala za opturaciju (gutaperkom i resilonom). U zavisnosti od tehnike uklanjanja ovih materijala, grupe su dalje podeljene u odnosu na kori&scaron;ćene instrumente (Hedstrom, ProTaper i Twisted File) i u odnosu na upotrebu rastvarača (sa i bez hloroforma). Preostalih 5 zuba, bez kanalnog punjenja, kori&scaron;ćeni su kao kontrolna grupa. Nakon zavr&scaron;enog retretmana, korenovi su uzdužnim cepanjem razdvojeni, a odabrane polovine posmatrane na SEM-u. Mikrofotografije svake trećine kanala načinjene su pri uveličanju od 500x. Količina preostalog materijala za punjenje ocenjivana je pomoću skale. Otvoreni dentinski kanalići prebrojavani su na mikrofotografijama načinjenim pri uveličanju od 1000x, u odnosu na uvek konstantnu povr&scaron;inu. Rezultati: Analiza rezultata ukazala je na postojanje statistički značajne razlike u kvalitetu či&scaron;ćenja zidova kanala u zavisnosti od uklanjanog materijala za opturaciju. Kvalitet či&scaron;ćenja zidova kanala bio je veći nakon uklanjanja gutaperke nego nakon uklanjanja resilona. Rotirajućim, ma&scaron;inskim instrumentima je efikasnije uklanjana gutaperka, a ručnim Hedstrom turpijama je bolje uklanjan resilon. Posmatrajući ceo uzorak, ProTaper instrumenti ostavljali su velike količine materijala na zidovima kanala nakon endodontskog retretmana. Međutim, uklanjanje materijala pomoću ovih instrumenata bilo je najbrže. Primena rastvarača značajno je doprinela bržem uklanjanju materijala, dok uticaj na kvalitet či&scaron;ćenja zidova kanala nije bio značajan. Posmatrajući kanal korena po trećinama, najveća količina materijala nalazila se u apikalnoj trećini, bez obzira na vrstu uklanjanog materijala i kori&scaron;ćenih instrumenata, i bez obzira na upotrebu rastvarača tokom retretmana. Učestalost o&scaron;tećenja instrumenata bila je značajno veća prilikom upotrebe Twisted File instrumenata. Apikalna transportacija materijala je bila veća tokom uklanjanja resilon materijala i kada su kori&scaron;ćene ručne Hedstrom turpije. Zaključak: Kvalitet či&scaron;ćenja zidova kanala nakon uklanjanja gutaperke je veći nego nakon uklanjanja resilona. Dizajn i vrsta instrumenata utiče na kvalitet či&scaron;ćenja zidova kanala korena. Upotreba rastvarača tokom retretmana ne utiče značajno na smanjenje količine materijala zaostalog na zidovima kanala. Ma&scaron;inski pokretani instrumenti i upotreba rastvarača značajno skraćuju vreme potrebno za endodontski retretman.</p> / <p>In cases when endodontic treatment fails, it is necessary to retreat the root canal. Orthograde endodontic retreatment requires the removal of the existing root filling material with additional cleaning, disinfection and refilling of the canal. An important step during retreatment is complete removal of existing filling materials, to regain access to all parts of the canal system. The aim of the doctoral thesis was to investigate the cleanliness of root canal walls after removal of two different obturation material. The retreatment efficacy was observed depending on the usage of solvent and different hand or rotary instruments. The amount of residual material on the canal walls was assessed using scanning electron microscopy (SEM). Also, apical transportation of the obturation material, working time and frequency of instrument damage during retreatment was recorded. Materials and Methods: The total sample consisted of 125 extracted, single-rooted human teeth. After root canal preparation, 120 teeth were divided in two groups and filled using two different obturation materials (gutta-percha and resilon). Depending on the technique of removing these materials, the groups were further divided, in relation to the used instruments (Hedstrom, ProTaper and Twisted File), as well as in relation to the use of solvent (with or without chloroform). The remaining 5 tooth without canal filling were used as a control group. After root canal desopturation, the longitudinaly splitted root halves were observed on SEM. Microphotography of each third were made at magnification of 500x. The amount of remaining filling material was evaluated by using a scale. Open dentinal tubules were counted on microphotographies made at a magnificiation of 1000x, on a surface that was always constant. Results: Analysis of the results indicated a significant difference in the cleanliness of the canal walls depending on the used obturation material. Cleanliness of the canal walls was higher after gutta-percha removal than after the removal of resilon.&nbsp; Rotary instruments were more effective in removing gutta-percha and Hedstrom hand files better removed resilon. ProTaper instruments left more residual material on canal walls, however endodontic retreatment with these instruments was the fastest. The application of solvent significantly contributed to faster material removal, while the impact on the increase of canal cleanliness was not significant. The largest amount of material remained in the apical third, regardless of the type of material removed and instruments used, and also regardless whether solvent was used for retreatment. The frequency of instrument deformation and fracture was significantly higher when Twisted File instruments were used. Apical transportation of material had a significantly higher occurrence during resilon removal and when manual Hedstrom files were used. Conclusion: Cleanliness of the canal walls was higher after the removal of gutta-percha than after the removal of resilon. The use of solvent is not significant on the increase of canal wall cleanliness, but significantly shortens the time needed for retreatment. There is a difference in the cleanliness of root canal walls depending on the used instruments. Engine-driven rotary instruments and the use of a solvent significantly shortens the time needed for endodontic retreatment.</p>

Indiana University-Purdue University Indianapolis (IUPUI) / INTRODUCTION: New sealers have been placed on the market to improve the property of a hermetic seal within the root canal and decrease the gap between the gutta-percha and dentin wall. Differences in the adhesive properties of endodontic sealers may be expected because their interaction with either dentin or gutta-percha may vary with their chemical composition. No specific interaction either with dentin or gutta-percha is expected from the setting reaction of calcium hydroxide based sealers and the epoxy-based sealers. The setting reaction of the zinc oxide-eugenol mixtures is a chelation reaction occurring with the zinc ion of the zinc oxide. Development and maintenance of the seal are essential to optimize the long-term success rate of root canal treatment. An ideal endodontic sealer should, in part, adhere firmly both to dentin and gutta-percha. PURPOSE: The purpose of this study is to evaluate the sealing properties of EndoSequence BC sealer TM ,a bioceramic sealer, and Roth’s sealer using gutta-percha with warm vertical condensation and using the single cone technique with the EndoSequence BC sealer only. The goal is to see if there is a significant difference in microleakage between teeth sealed with the bioceramic sealer and teeth sealed with Roth’s sealer. MATERIALS & METHODS: Eighty-five single-rooted maxillary anterior teeth were used for this study. Endodontic cleaning and shaping of each root canal system was accomplished using K-type hand files and NiTi Rotary files. Group A consisted of twenty-seven anterior teeth, which were obturated using EndoSequence BC sealer and gutta-percha with System B and Obtura. Another twenty-seven anterior teeth, Group B, was obturated using Roth’s sealer and gutta-percha with System B and Obtura. A final group, Group C with 27 teeth was obturated using the single cone technique by means of a single gutta-percha point with Endosequence BC sealer. Two teeth were used as a positive control group, and two other teeth as a negative control group. A microbial leakage apparatus was constructed using a similar two-chamber method described by Torabinejad et al. E. faecalis ATCC 29212 was the test bacteria which was used in this study to determine microleakage The outcome of interest (bacterial turbidity) and time-to-leakage (in days), will be determined for each of the samples. Survival analysis will be used to compare the two groups, with a Kaplan-Meier plot to visualize the results and a nonparametric log-rank test for the group comparison RESULTS: No microleakage was observed in the negative control or group B. Microleakage was observed in all the positive control. Group A and C had a significantly higher proportion of samples with microleakage than group B (p<0.0001), but group A and C were not significantly different from each other (p=0.50). Time to microleakage was also significantly lower in group A and C than group B (p<0.0001), but group A and C were not significantly different from each other (p=0.37). CONCLUSION: In conclusion, using E. faecalis as our test bacteria, the microleakage of canals obturated with gutta percha and Roth's sealer was significantly less than canals obturated with gutta percha and EndoSequence BC sealer.

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Objetivo: Evaluar la eficacia disolvente de una sustancia experimental a base de Aceite esencial de Myrciaria dubia en la desobturación de conductos radiculares. Materiales y métodos: Se utilizaron 60 tubos de PLA (ácido poliláctico)que fueron divididos en 5 grupos de 12 especímenes. Estos se rellenaron con un material de restauración temporal (coltosol) el primer tercio y el tercio medio con gutapercha. Se añadió un total de 0,1 ml de disolvente dependiendo del grupo de estudio (Agua destilada,camu camu, xilol,aceite de cascara de naranja y de eucalipto) a la parte superior de los tubos de PLA. Después de 5 minutos, se utilizó la máquina Instron 5566 (Instron, Buckinghamshire, UK) se movió hacia abajo a través de gutapercha con una velocidad de cabecera de 5 mm / min a una profundidad de 5 mm min. La carga(fuerza) utilizada para penetrar el separador en la profundidad de 5 mm se registró en Newton. Para el análisis se realizará la prueba de kruskal Wallis para comparar la medida fuerza de penetración según el tipo de solvente, posterior a comprobarse los supuestos estadísticos. Resultados: Se encontraron diferencias estadísticamente significativas al comparar todos los solventes (p= 0.001), obteniendo 14.02N para la sustancia experimental. Los resultados de la profundidad de disolución superficial y la fuerza utilizada para penetrar el esparcidor a 5 mm revelaron que el Aceite de Myrciaria Dubia ( Camu Camu) fue significativamente el mejor solvente para ablandar la gutapercha (P <0.05), seguido del xilol y el aceite de cascara de naranja, mientras que el disolvente con menos efectividad fue el aceite de eucalipto. Conclusiones: El aceite esencial de Myrciaria Dubia presento mayor poder reblandecedor que las demás soluciones en estudio. / Objective: To evaluate the solvent efficacy of an experimental substance based on Myrciaria dubia essential oil in the desobturation of root canals. Materials and methods: 60 PLA (polylactic acid) tubes were used, which were divided into 5 groups of 12 specimens. These were filled with a temporary restoration material (coltosol) the first third and the middle third with gutta-percha. A total of 0.1 ml of solvent was added depending on the study group (distilled water, camu camu, xylol, oil of orange peel and eucalyptus) to the top of the PLA tubes. After 5 minutes, the Instron 5566 machine (Instron, Buckinghamshire, UK) was used and moved down through gutta-percha with a head speed of 5 mm / min at a depth of 5 mm min. The load (force) used to penetrate the separator to the depth of 5 mm was recorded in Newton. For the analysis, the kruskal Wallis test will be carried out to compare the penetration force measure according to the type of solvent, after checking the statistical assumptions. Results: Statistically significant differences were found when comparing all solvents (p = 0.001), obtaining 14.02N for the experimental substance. The results of the surface dissolution depth and the force used to penetrate the spreader to 5 mm revealed that Myrciaria Dubia Oil (Camu Camu) was significantly the best solvent to soften gutta-percha (P <0.05), followed by xylol and orange peel oil, while the least effective solvent was eucalyptus oil. Conclusions: The essential oil of Myrciaria Dubia presented greater softening power than the other solutions under study. / Tesis

O controle da extrusão apical durante a reintervenção endodôntica é essencial para o sucesso do novo tratamento. Nesse contexto, o presente estudo teve como objetivo comparar a quantidade de material sólido extruído na desobturação de canais radiculares variando-se a técnica de esvaziamento e o limite de obturação. Foram utilizados 40 incisivos inferiores previamente tratados divididos em dois grupos de acordo com o limite de obturação estabelecido. Cada grupo foi subdividido em dois subgrupos levando-se em conta a técnica de desobturação empregada; manual (subgrupos A1 e B1) e mecânico-rotatória com limas de Ni-Ti (Quantec LX) (subgrupos A2 e B2). O material sólido extruído foi coletado por meio do sistema de filtração Millipore, levado à secagem em dessecador de sílica e pesado em balança analítica de precisão. Os resultados obtidos foram submetidos a ANOVA para dois fatores de variação sendo em seguida empregado o Teste de Tukey (&#945; = 5%). A técnica de desobturação mecânico-rotatória produziu menor extrusão (0,66mg) que a manual (1,11mg), havendo diferença estatística significante entre elas (p < 0,05). Os canais preenchidos até o vértice radiográfico apresentaram maior quantidade de extrusão (1,38mg) do que os obturados 1 mm aquém do forame (0,39mg), observando-se diferença estatística significante entre eles (p < 0,05). A menor quantidade extrusão foi observada no subgrupo A2 (0,20mg), em que foi empregada a técnica rotatória de desobturação em canais obturados 1mm aquém do forame apical, sendo constatada diferença estatisticamente significante deste subgrupo com os demais (p < 0,05). A extrusão de material sólido durante a desobturação de canais radiculares é influenciado pela técnica empregada e pelo limite apical de obturação. / The apical extrusion control during the endodontic retreatment is essential for the success of the new treatment. The purpose of this study was to compare the quantity of solid apically extruded material during filling removal according the gutta-percha removal technique and root filling limit. Forty mandibular incisors with a single straight canal were selected. The canals were previously endodontically treated and then divided into two groups according the filling level. Each group was subdivided in two groups considering the retreatment technique: stainless steel hand files (subgroups A1 and B1) versus niquel-titanium rotatory instruments (subgroups A2 and B2). The extruded solid material was collected by Millipore filtration system, dried in silica desiccators and weighed in an eletrobalance. The results were analyzed using ANOVA with two variation factors and Tukey Test (&#945; = 5%). The niquel-titanium rotatory instruments produced less extrusion (0,66mg) than the stainless steel hand files (1,11mg), with significant statistical difference between them (p < 0,05). The canals filled until the radiographic apex showed larger amount of extruded material (1,38mg) than those filled 1 mm beyond the foramen (0,39mg). It was observed significant statistical difference between them (p < 0,05). The smaller extruded debris amount was observed in subgroup A2 (0,20mg), in which one the rotary technique was used to remove the gutta-percha of canals filled 1mm beyond the apical foramen. It was verified significant statistical difference of this subgroup with the other ones (p < 0,05). The extrusion of solid material during the gutta-percha removal is influenced by the technique as well as the apical filling limit.

O controle da extrusão apical durante a reintervenção endodôntica é essencial para o sucesso do novo tratamento. Nesse contexto, o presente estudo teve como objetivo comparar a quantidade de material sólido extruído na desobturação de canais radiculares variando-se a técnica de esvaziamento e o limite de obturação. Foram utilizados 40 incisivos inferiores previamente tratados divididos em dois grupos de acordo com o limite de obturação estabelecido. Cada grupo foi subdividido em dois subgrupos levando-se em conta a técnica de desobturação empregada; manual (subgrupos A1 e B1) e mecânico-rotatória com limas de Ni-Ti (Quantec LX) (subgrupos A2 e B2). O material sólido extruído foi coletado por meio do sistema de filtração Millipore, levado à secagem em dessecador de sílica e pesado em balança analítica de precisão. Os resultados obtidos foram submetidos a ANOVA para dois fatores de variação sendo em seguida empregado o Teste de Tukey (&#945; = 5%). A técnica de desobturação mecânico-rotatória produziu menor extrusão (0,66mg) que a manual (1,11mg), havendo diferença estatística significante entre elas (p < 0,05). Os canais preenchidos até o vértice radiográfico apresentaram maior quantidade de extrusão (1,38mg) do que os obturados 1 mm aquém do forame (0,39mg), observando-se diferença estatística significante entre eles (p < 0,05). A menor quantidade extrusão foi observada no subgrupo A2 (0,20mg), em que foi empregada a técnica rotatória de desobturação em canais obturados 1mm aquém do forame apical, sendo constatada diferença estatisticamente significante deste subgrupo com os demais (p < 0,05). A extrusão de material sólido durante a desobturação de canais radiculares é influenciado pela técnica empregada e pelo limite apical de obturação. / The apical extrusion control during the endodontic retreatment is essential for the success of the new treatment. The purpose of this study was to compare the quantity of solid apically extruded material during filling removal according the gutta-percha removal technique and root filling limit. Forty mandibular incisors with a single straight canal were selected. The canals were previously endodontically treated and then divided into two groups according the filling level. Each group was subdivided in two groups considering the retreatment technique: stainless steel hand files (subgroups A1 and B1) versus niquel-titanium rotatory instruments (subgroups A2 and B2). The extruded solid material was collected by Millipore filtration system, dried in silica desiccators and weighed in an eletrobalance. The results were analyzed using ANOVA with two variation factors and Tukey Test (&#945; = 5%). The niquel-titanium rotatory instruments produced less extrusion (0,66mg) than the stainless steel hand files (1,11mg), with significant statistical difference between them (p < 0,05). The canals filled until the radiographic apex showed larger amount of extruded material (1,38mg) than those filled 1 mm beyond the foramen (0,39mg). It was observed significant statistical difference between them (p < 0,05). The smaller extruded debris amount was observed in subgroup A2 (0,20mg), in which one the rotary technique was used to remove the gutta-percha of canals filled 1mm beyond the apical foramen. It was verified significant statistical difference of this subgroup with the other ones (p < 0,05). The extrusion of solid material during the gutta-percha removal is influenced by the technique as well as the apical filling limit.