Morphological changes in the enamel that affects the bonding of brackets: a review

A literature review on the existing information about bonding of orthodontic brackets on altered enamel surfaces, the influence of such surfaces on adhesion, and the most favorable conditions for achieving better bond strength is presented. Studies on bracket adhesion have identified the conditions that lead to morphological changes in enamel as dental fluorosis and dental bleaching. In this review, each of these conditions that alter the enamel surface and pose a major challenge to clinical orthodontists performing bracket bonding, will be analyzed. The literature provides a range of approaches for overcoming the challenges of bonding on altered enamel surfaces and will be discussed, taking into account, where possible, the type of adhesive selected. Adhesion on enamel that is fluorosed depends on the degree of severity and the bond strength on a bleached enamel surface depends largely on the concentration of the bleaching agent.

Endodontic surgery with simultaneous root canal filling: case report

Introduction: Endodontic surgery is an excellent alternative for solving problems unsolved by conventional treatments and/or root canal retreatment. Objective: This study aims to report a clinical case of an endodontic surgery with simultaneous root canal filling. Case report: The left mandibular lateral incisor (#32) showed constant exudation even after root canal instrumentation and many changes of calcium hydroxide paste as intracanal medication. So, the treatment´s option was the endodontic surgery with simultaneous root canal filling for removing the periapical lesion. After the root canal filling, the curettage and apical plasty were made and the bone cavity was filled with calcium sulfate. Histopathological examination pointed out a periapical cyst. Conclusion: Endodontic surgery with simultaneous root canal filling of the tooth #32 was successful, once the patient did not exhibited any clinical symptoms, the exudate disappeared, and radiographically, it can be observed the formation of bone repair. The time of follow-up was of four months.

In vivo accuracy of conventional and digital radiographic methods in confirming root canal working length determination by Root ZX

OBJECTIVES: To compare, in vivo, the accuracy of conventional and digital radiographic methods in determining root canal working length. MATERIAL AND METHODS: Twenty-five maxillary incisor or canine teeth from 22 patients were used in this study. Considering the preoperative radiographs as the baseline, a 25 K file was inserted into the root canal to the point where the Root ZX electronic apex locator indicated the APEX measurement in the screen. From this measurement, 1 mm was subtracted for positioning the file. The radiographic measurements were made using a digital sensor (Digora 1.51) or conventional type-E films, size 2, following the paralleling technique, to determine the distance of the file tip and the radiographic apex. RESULTS: The Student "t" test indicated mean distances of 1.11 mm to conventional and 1.20 mm for the digital method and indicated a significant statistical difference (p<0.05). CONCLUSIONS: The conventional radiographic method was found to be superior to the digital one in determining the working length of the root canal.

Sealing ability, marginal adaptation and their correlation using three root-end filling materials as apical plugs

OBJECTIVE: This study used dye leakage assay and scanning electron microscopy to evaluate, respectively, the sealing ability and marginal adaptation of three root-end filling materials used as apical plugs, as well as the possible correlation between these properties. MATERIAL AND METHODS: Ninety-eight single-rooted human teeth were prepared to simulate an open apex. The teeth were allocated to three experimental groups (n = 30), which received a 5-mm thick apical plug of (1) gray MTA AngelusTM, (2) CPM TM and (3) MBPc, and two controls groups (n = 4). After immersion in 0.2 percent Rhodamine B solution for 48 h, the teeth were sectioned longitudinally and analyzed by Image Tool 3.0 software. The marginal adaptation between apical plugs and the root canal walls were analyzed by SEM. RESULTS: MBPc had significantly less (p<0.05) apical leakage than the other materials. Regarding marginal adaptation, CPM TM showed the best numerical results, though without statistical significance from the other materials (p<0.05). There was no correlation between the two properties. CONCLUSIONS: When used as apical plugs, the tested root-end filling materials had similar marginal adaptation to the dentin walls, but MBPc had the best sealing ability, as demonstrated by the least apical leakage from all tested materials.

Influência da espessura de dentina, da constrição apical e do diâmetro do forame apical na precisão de leitura com localizadores foraminais eletrônicos / Influence of dentin thickness, apical constriction and diameter of the apical foramen in the accuracy of readings with electronic apex locators

Este trabalho teve como objetivo avaliar a influência da espessura de dentina radicular apical, da constrição apical e do diâmetro do forame apical na precisão de leituras realizadas com os localizadores foraminais eletrônicos Mini Apex Locator e Root ZX II®. Foram utilizados 30 incisivos inferiores permanentes unirradiculados de humanos, extraídos, com raízes íntegras e ápices completamente formados e portadores de um único canal. Por meio de um paquímetro, as espessuras radiculares dos dentes foram medidas, no sentido mésio-distal a 1,0 e a 4,0mm aquém do forame apical. Após a abertura coronária, uma lima tipo K no 10, munida de limitador de penetração, foi introduzida no canal radicular até que sua extremidade pudesse ser visualizada na altura do forame, com o auxílio de um microscópio óptico com aumento de 7,8X. Dessa medida, subtraiu-se 1,0mm, estabelecendo-se o comprimento de trabalho. A dilatação do canal radicular foi feita, inicialmente, com brocas de Gates Glidden, em ordem numérica decrescente, da número 5 até a número1, até 4,0mm aquém do forame apical. Os dentes foram fixados em um modelo experimental especialmente desenvolvido para permitir a medição com os localizadores foraminais eletrônicos. Tal modelo era constituído por dois segmentos de PVC: um de menor calibre, com diâmetro correspondente a meia polegada por 2,0cm de comprimento, com as duas extremidades abertas e outro, de maior calibre, com uma das extremidades fechada e com diâmetro interno equivalente ao diâmetro externo do primeiro segmento (3/4 de polegada). No segmento de maior diâmetro, foi feito um orifício lateral que permitiu o posicionamento do eletrodo labial do localizador foraminal eletrônico e, para a medição, no seu interior, foi colocado alginato e, então, encaixado o componente de menor diâmetro, fazendo com que o ápice radicular ficasse imerso no alginato. Foram realizadas as leituras com os localizadores, iniciando-se com a lima tipo K no 10 e seguindo-se...

This study evaluated the influence of the apical root dentin thickness, apical constriction and diameter of the apical foramen in the accuracy of readings obtained using the electronic apex locators Mini Apex Locator and Root ZX II ®. The study was conducted on 30 extracted human single-rooted permanent mandibular incisors, with intact and completely formed roots and presenting a single canal. The root thickness of the teeth was measured with a pachymeter in mesiodistal direction, at 1.0 and 4.0mm from the apical foramen. After coronal opening, a 10 K file with a stop was introduced in the root canal until its end could be observed at the level of the apical foramen, with aid of a light microscope with 7.8X magnification. One millimeter was subtracted from this measurement for establishment of the working length. Enlargement of the root canal was initially performed using Gates Glidden burs, in decreasing order, from number 5 to number 1, up to 4.0mm beyond the apical foramen. The teeth were fixated in an experimental model especially designed to allow the measurement with the electronic apex locators. This model was composed of two PVC segments: one smaller, with diameter corresponding to half inch with 2.0cm length, with both ends open; and the other, with larger diameter, with one end closed and internal diameter similar to the external diameter of the first segment (3/4 inch). In the segment with greater diameter, a lateral orifice was made to allow positioning of the lip electrode of the electronic apex locator. For the measurement, alginate was poured and the component with smaller diameter was fitted, so as the root apex was immersed in alginate. Readings were performed using the electronic apex locators, initiating with a 10 K file and following the sequence of instrumentation and measurement up to 130 K file. The 10 K file was used in all diameters. After this stage, the root canals were overinstrumented, i.e. the file tip was introduced until 1.0mm...

Influência da espessura de dentina, da constrição apical e do diâmetro do forame apical na precisão de leitura com localizadores foraminais eletrônicos / Influence of dentin thickness, apical constriction and diameter of the apical foramen in the accuracy of readings with electronic apex locators

Este trabalho teve como objetivo avaliar a influência da espessura de dentina radicular apical, da constrição apical e do diâmetro do forame apical na precisão de leituras realizadas com os localizadores foraminais eletrônicos Mini Apex Locator e Root ZX II®. Foram utilizados 30 incisivos inferiores permanentes unirradiculados de humanos, extraídos, com raízes íntegras e ápices completamente formados e portadores de um único canal. Por meio de um paquímetro, as espessuras radiculares dos dentes foram medidas, no sentido mésio-distal a 1,0 e a 4,0mm aquém do forame apical. Após a abertura coronária, uma lima tipo K no 10, munida de limitador de penetração, foi introduzida no canal radicular até que sua extremidade pudesse ser visualizada na altura do forame, com o auxílio de um microscópio óptico com aumento de 7,8X. Dessa medida, subtraiu-se 1,0mm, estabelecendo-se o comprimento de trabalho. A dilatação do canal radicular foi feita, inicialmente, com brocas de Gates Glidden, em ordem numérica decrescente, da número 5 até a número1, até 4,0mm aquém do forame apical. Os dentes foram fixados em um modelo experimental especialmente desenvolvido para permitir a medição com os localizadores foraminais eletrônicos. Tal modelo era constituído por dois segmentos de PVC: um de menor calibre, com diâmetro correspondente a meia polegada por 2,0cm de comprimento, com as duas extremidades abertas e outro, de maior calibre, com uma das extremidades fechada e com diâmetro interno equivalente ao diâmetro externo do primeiro segmento (3/4 de polegada). No segmento de maior diâmetro, foi feito um orifício lateral que permitiu o posicionamento do eletrodo labial do localizador foraminal eletrônico e, para a medição, no seu interior, foi colocado alginato e, então, encaixado o componente de menor diâmetro, fazendo com que o ápice radicular ficasse imerso no alginato. Foram realizadas as leituras com os localizadores, iniciando-se com a lima tipo K no 10 e seguindo-se...

This study evaluated the influence of the apical root dentin thickness, apical constriction and diameter of the apical foramen in the accuracy of readings obtained using the electronic apex locators Mini Apex Locator and Root ZX II ®. The study was conducted on 30 extracted human single-rooted permanent mandibular incisors, with intact and completely formed roots and presenting a single canal. The root thickness of the teeth was measured with a pachymeter in mesiodistal direction, at 1.0 and 4.0mm from the apical foramen. After coronal opening, a 10 K file with a stop was introduced in the root canal until its end could be observed at the level of the apical foramen, with aid of a light microscope with 7.8X magnification. One millimeter was subtracted from this measurement for establishment of the working length. Enlargement of the root canal was initially performed using Gates Glidden burs, in decreasing order, from number 5 to number 1, up to 4.0mm beyond the apical foramen. The teeth were fixated in an experimental model especially designed to allow the measurement with the electronic apex locators. This model was composed of two PVC segments: one smaller, with diameter corresponding to half inch with 2.0cm length, with both ends open; and the other, with larger diameter, with one end closed and internal diameter similar to the external diameter of the first segment (3/4 inch). In the segment with greater diameter, a lateral orifice was made to allow positioning of the lip electrode of the electronic apex locator. For the measurement, alginate was poured and the component with smaller diameter was fitted, so as the root apex was immersed in alginate. Readings were performed using the electronic apex locators, initiating with a 10 K file and following the sequence of instrumentation and measurement up to 130 K file. The 10 K file was used in all diameters. After this stage, the root canals were overinstrumented, i.e. the file tip was introduced until 1.0mm...

Sealing ability of grar MTA AngelusTM, CPM TM and MBPc used as apical plugs

This study evaluated the sealing ability of apical plugs fabricated with gray MTA AngelusTM sealer, CPM TM sealer and MBPc sealer. The root canals of 98 extracted single-rooted human teeth were instrumented with #5 to #1 Gates Glidden drills according to the crown-down technique until the #1 drill could pass through the apical foramen. The specimens were then prepared with K-files, starting with an ISO 50 until an ISO 90 could be visualized 1 mm beyond the apex. After root canal preparation, the external surface of each root was rendered impermeable and roots were assigned to 3 experimental groups (n = 30), which received a 5-mm thick apical plug of gray MTA AngelusTM, CPM TM and MBPc, and two control groups (n=4). The remaining portion of the canal in the experimental groups was filled by the lateral condensation technique. The teeth of each group, properly identified, were fixed on utility wax by their crowns and were placed in plastic flasks, leaving the apex free and facing upward. The flasks were filled with 0.2 percent Rhodamine B solution, pH 7.0, so as to completely cover the root apex of all teeth. The sealing ability was analyzed by measuring 0.2 percent Rhodamine B leakage after all groups had been maintained in this solution for 48 hours. Data were analyzed statistically by Kruskal-Wallis test and Dunn test with a=5 percent. The results showed that, among the tested materials used for fabrication of apical plugs, MBPc sealer had the least amount of leakage with statistically significant difference (p<0.05).

In vitro sealing ability of white and gray mineral trioxide aggregate (MTA) and white Portland cement used as apical plugs

This study evaluated the sealing ability of apical plugs made of white and gray MTA-Angelus® and white Portland cement placed via the root canal and having different thicknesses (2, 5 and 7 mm). Ninety extracted human single-rooted teeth were instrumented using a size 40 K-file to standardize the foraminal opening by the stepback technique. The teeth were assigned to 3 groups (n=30), according to the material used for fabrication of the apical plugs: A = gray MTA; B = white MTA; C = white Portland cement. The groups were subdivided into groups of 10 teeth each according to the apical plug thickness (2, 5 and 7 mm). Marginal apical dye leakage was assessed using 0.2 percent Rhodamine B solution in which the specimens were immersed for 72 hours at 37°C. The roots were sectioned longitudinally in a buccolingual direction for apical plug exposure, and digital photographs were taken and analyzed by Image Tool image-analysis software. Data were analyzed statistically by Kruskal-Wallis and Dunn's tests. Significance level was set at 5 percent. The least percent leakage was observed for 5- and 7-mm-thick plugs (p<0.05). No significant difference (p>0.05) was found between gray MTA and white Portland cement. Among the three materials analyzed, white MTA presented the highest marginal leakage (p<0.05). The findings of the present study showed that gray MTA and Portland cement had better sealing ability than white MTA when used as apical plugs. Dye leakage was smaller for 5- and 7-mm-thick plugs compared to 2-mm-thick plugs.