Comparison of Fracture Resistance of Simulated Immature Teeth Using Four Different Commercially Available Apexification Materials ? An invitro Study

Introduction: The aim of this study was to compare the fracture resistance of simulated immature teeth using four different apical plug materials, i.e. Pro? Root MTA, Neo? MTA Plus, Biodentine, and Bioactive Glass. Materials and Methods: 80 extracted human maxillary anterior teeth were divided into 4 groups for this study. They were prepared using Peeso reamers to simulate immature teeth and to mimic Cvek’s stage 3 of root development. A 5 mm apical barrier was placed using different materials. The remaining canal was obturated using gutta?percha and AH plus sealer. The final samples were stored at 37°C and 100% humidity for 4 weeks. Fracture resistance of the teeth was measured in Newtons using a universal testing machine. The comparison of fracture resistance between the four groups was done using Kruskal Walis ANOVA followed by post hoc Mann Whitney U test for pairwise comparison. Results: Biodentine group showed the highest fracture resistance as compared to the other three groups and the difference was highly significant (P < 0.001). Conclusions: Biodentine can be advocated over MTA as an effective material for the management of teeth with wide open apex. Bioactive glass also has shown promising results in increasing the fracture resistance of simulated immature teeth.

Ex Vivo Evaluation of a Restoration Protocol for Teeth with Simulated Incomplete Rhizogenesis / Evaluación ex vivo de un protocolo de restauración para dientes con rizogénesis incompleta simulada

Abstract: The use of phosphate buffered saline (PBS) as an intracanal medication triggers a biomineralization process within mineral trioxide aggregate (MTA) apical plugs during the apexification process in teeth with incomplete rhizogenesis. However, no consensus is available in the literature regarding a restorative protocol for this type of treatment. Thus, the objective of this study was to use scanning electron microscopy (SEM) to evaluate the processes of biomineralization and adhesion in a restorative protocol for teeth with simulated incomplete rhizogenesis. Methodology: Root sections with a thickness of 2mm and cavities with a diameter of 2mm were used. The sections were randomly prepared and filled with the following materials: Group 1 (n=12), ProRoot MTA; and Group 2 (n=12): MTA Exp. Subsequently, the samples were immersed in PBS for 35 days. Every 5 days, the PBS was replaced, and the precipitates were collected, dried, and weighed. Two samples from each group were analyzed by SEM. Moreover, 24 single-rooted teeth were standardized, incomplete rhizogenesis was simulated, and 5-mm-long apical plugs were created with Pro Root MTA. As an intracanal medication, PBS was used for different periods of time: Group 1:48 h; Group 2:7 days; and Group 3:15 days. Then, fiberglass posts were cemented with the REBILDA® Post System. The samples were prepared and analyzed by SEM. Results: ProRoot MTA and MTA Exp effectively promoted the formation of carbonated apatite precipitates and biomineralization with dentin. ProRoot MTA yielded more carbonated apatite precipitates compared to MTA Exp (p=0.0536). The use of PBS as an intracanal medication for 7 and 15 days promoted intratubular mineralization (MIT), and treatment for 15 days was more effective (p < 0.05). The REBILDA® Post System effectively promoted the microimbrication of the adhesive system and the formation of resinous tags with lateral adhesive branches. Conclusion: Apexification with MTA associated with the use of PBS as an intracanal medication for 15 days, in addition to the use of the REBILDA® Post System, seems to be a feasible restorative protocol.

Resumen: El uso de solución salina tamponada con fosfato (PBS) como medicamento intracanal desencadena un proceso de biomineralización en los plugs apicales con agregado de trióxido mineral (MTA) durante el proceso de apexificación en dientes con rizogénesis incompleta. Sin embargo, no hay consenso disponible en la literatura sobre un protocolo restaurador para este tipo de tratamiento. Por lo tanto, el objetivo de este estudio fue utilizar microscopía electrónica de barrido (MEB) para evaluar los procesos de biomineralización y adhesión en un protocolo restaurador para dientes con rizogénesis incompleta simulada. Metodología: Se utilizaron secciones de raíz con un espesor de 2mm y se realizaron cavidades con un diámetro de 2 mm. Las cavidades en las secciones se obturaron con: Grupo 1 (n=12), ProRoot MTA; y Grupo 2 (n=12): MTA Exp. Posteriormente, las muestras se sumergieron en PBS durante 35 días. Cada 5 días, se reemplazó el PBS y se recogieron los precipitados, se secaron y pesaron. Dos muestras de cada grupo fueron analizadas por MEB. Además, se estandarizaron 24 dientes de raíz única, se simuló la rizogénesis incompleta y se crearon tapones apicales de 5mm de longitud con Pro Root MTA. Como medicamento intracanal, se utilizó PBS durante diferentes períodos de tiempo: Grupo 1:48 h; Grupo 2:7 días; y Grupo 3:15 días. Posteriormente, los postes de fibra de vidrio se cementaron con el sistema de postes REBILDA®. Las muestras fueron preparadas y analizadas por MEB. Resultados: ProRoot MTA y MTA Exp promovieron efectivamente la formación de precipitados de apatita carbonatada y la biomineralización con dentina. ProRoot MTA produjo más precipitados de apatita carbonatada en comparación con MTA Exp (p=0.0536). El uso de PBS como medicamento intracanal durante 7 y 15 días promovió la mineralización intratubular (MIT), siendo el tratamiento durante 15 días más efectivo (p <0.05). El sistema de postes REBILDA® promovió efectivamente la microimbricación del sistema adhesivo y la formación de tags resinosos. Conclusión: La apexificación con MTA asociada con el uso de PBS como medicación intracanal durante 15 días, además del uso del sistema de postes REBILDA®, parece ser un protocolo factible y eficaz en este tipo de tratamientos.

Endodontic treatment for necrotic immature permanent teeth using MTA and calcium hydroxide: A retrospective study

Introduction: Endodontic treatment of young permanent teeth with incomplete root formation and necrotic pulp has been a challenge for the dentist. It is necessary to induce the formation of apical barrier (apical plug), enabling the complete root canal filling. Objective: This retrospective clinical study compared the protocols for treatment of teeth with incomplete root formation, using calcium hydroxide (CH) or mineral trioxide aggregate (MTA). Material and methods: 28 patients with incomplete root formation have undergone root canal treatments in the period from 2000 to 2009 were selected. The procedures for cleaning, shaping and intracanal medication (CH paste) were performed in a standardized manner. In 13 patients, after using the CH paste (14 days), apical plugs with MTA were made. In the remaining 15 teeth monthly exchanges with CH paste were executed until it was observed radiographically the formation of the apical barrier. In all cases the canals were filled conventionally with gutta-percha and sealer. Initially, follow-ups were made on a quarterly and semiannually at the end of first year. Results: All apical lesions showed apical healing between 4 and 13 months after starting treatment. There was not noted the continuing process of root formation. Conclusion: It was concluded that the treatment of teeth with incomplete root formation and necrotic pulp with the use of MTA as apical plug has the same clinical results compared with the use of CH, with the advantage of less clinical time.

Healing of a tooth with an overinstrumented apex, extensive transportation and periapical lesion using a 5 mm calcium hydroxide apical plug: an 8-year follow-up report

Besides the risk of filling material extrusion throughout the apex, a satisfactory apical seal can be difficult to achieve in canals with open apices or iatrogenic enlargements of the apical constriction. These situations pose a challenge to root canal filling. This paper describes the root canal filling of a maxillary right canine with an overinstrumented apex, complete loss of the apical stop, extensive canal transportation and apical periodontitis. A 5 mm calcium hydroxide apical plug was placed before root canal filling. The plug was made by soaking paper points with saline, dipping the points in calcium hydroxide powder and then applying it to the apex several times, until a consistent apical plug was obtained. The canal was then irrigated with saline in order to remove any residual calcium hydroxide from the root canal walls, dried with paper points and obturated with an inverted #80 gutta-percha cone and zinc oxide-eugenol based sealer by the lateral condensation technique. An 8-year radiographic follow-up showed formation of mineralized tissue sealing the apical foramen, apical remodeling and no signs of apical periodontitis.

Além do risco de extrusão periapical de material obturador pelo ápice, pode ser difícil conseguir um bom selamento apical em dentes com rizogênese incompleta ou alargamentos iatrogênicos da constrição apical. Casos assim representam um desafio durante a obturação do canal. Este caso clínico descreve a obturação de um canino superior direito com perda total da constrição apical por sobreinstrumentação, transporte excessivo e lesão periapical. Antes da obturação foi feito um tampão apical de hidróxido de cálcio com 5 mm de extensão. Para a realização do tampão, pontas de papel absorvente foram umedecidas em soro fisiológico, levadas ao pó do hidróxido de cálcio para absorvê-lo e aplicadas várias vezes no ápice até se conseguir um tampão apical consistente. Em seguida o canal foi irrigado com solução salina para a remoção de eventuais resíduos de hidróxido de cálcio das suas paredes, secado com pontas de papel absorvente e obturado com um cone #80 de guta percha invertido e cimento obturador à base de óxido de zinco e eugenol pela técnica da condensação lateral. O acompanhamento radiográfico de 8 anos mostrou selamento apical por tecido mineralizado, remodelação do ápice e reparo da lesão periapical.

Effects of condensation techniques and canal sizes on the microleakage of orthograde MTA apical plug in simulated canals / 대한치과보존학회지

The purpose of this study was to compare the dye leakage of MTA (mineral trioxide aggregate) apical plug produced by two orthograde placement techniques (hand condensation technique and ultrasonically assisted hand condensation technique). To simulate straight canal, 60 transparent acrylic blocks with straight canal were fabricated. These transparent acrylic blocks were divided into 2 groups (Group C; hand condensation technique (HC) and Group U; ultrasonically assisted hand condensation technique (UAHC)) of 30 blocks with each MTA application method. Each group was divided into 2 subgroups (n = 15) with different canal size of #70 (subgroup C70 and subgroup U70) and #120 (subgroup C120 and subgroup U120). After apical plug was created, a wet paper point was placed over the MTA plug and specimen was kept in a humid condition at room temperature to allow MTA to set. After 24 hours, remaining canal space was backfilled using Obtura II. All specimens were transferred to floral form socked by 0.2% rhodamine B solution and stored in 100% humidity at room temperature. After 48 hours, resin block specimens were washed and scanned using a scanner. The maximum length of microleakage was measured from the scanned images of four surfaces of each resin block using Photoshop 6.0. Statistical analysis was performed with Mann-Whitney U test. Group U of UAHC had significantly lower leakage than Group C of HC in #70-size canal (subgroup U70) (p < 0.05).

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).