Reciprocating instrumentation in a maxillary primary central incisor: A protocol tested in a 3D printed prototype.

BACKGROUND: Efficient endodontic instrumentation of primary teeth is a challenge for paediatric dentists. AIM: To evaluate biomechanical outcomes of endodontic instrumentation with a reciprocating system in a polymer-prototyped primary maxillary central incisor. DESIGN: The specimen was systematically instrumented and micro-CT scanned before and after each file. The amount of debris, percentage of non-instrumented areas, removed dentin volume, and lower dentin thickness at specific points along the root canal were analyzed. RESULTS: A 10% increase in removed dentin volume was observed when R40 was compared to R25 (14.5% vs 4.2%). When comparing R50 with R40, this increase was only 3.4% (17.9% vs 14.5%). In the root cervical third, there was substantial reduction in dentin thickness with R50 (48.8%), followed by R40 (39.5%) and R25 (18.6%). There was no difference between R25 and R40 in the removal of dentin at the apical third (15.8%), while R50 resulted in 39.8% reduction in dentin thickness. Percentage of non-instrumented areas were the same for all files. Accumulated debris with R40 and R50 was the same (0.19 mm³) while for R25 was 0.11 mm³. CONCLUSIONS: The Reciproc® system was effective for instrumentation of a prototyped primary maxillary central incisor. The most suitable file for apical preparation was R40.

Micro-CT evaluation of root canal preparation with rotary instrumentation on prototyped primary incisors.

This study aimed to evaluate the endodontic instrumentation outcomes with asymmetrical files compared to reciprocating and hand files (HFs) in 3D-printed prototypes of upper primary incisors using micro-computed tomography (micro-CT). For this purpose, 50 prototypes were randomly divided (n = 10) according to the instrumentation technique as follows: HFs, a reciprocating file (WaveOne® Gold [WOG]), and three asymmetrical movement files: XP-Endo® Shaper (XPS), XP-Endo® Finisher (XPF), and XP Clean (XPC). The specimens were scanned and, after registration of the baseline and instrumented volumes, changes in the root canal volume (RCV), debris accumulation, removed root material volume (RRMV), non-instrumented areas, and the presence of cracks/perforations were quantified. Data were analyzed by analysis of variance and Student's t-test, while the effect size was calculated for statistically significant outcomes. All groups showed an increase in RCV after instrumentation (p < 0.05), but this was higher with HFs (p < 0.05). Accumulated debris was higher for WOG and XPS (p < 0.05), but WOG exhibited more in the medium and apical third areas. HFs showed the highest RRMV (p < 0.05), especially at the apical third. The non-instrumented areas were lower for HFs and XPC than for the other systems (p < 0.05). Cracks were present in a few WOG (n = 2) and HF specimens (n = 3) and in this group, one of the cracked specimens and two others showed perforations. The asymmetric systems resulted in conservative dentin removal and fewer cracks/perforations as compared to HFs and a reciprocation file in prototyped primary upper incisors. XPC showed the best compromise between RRMV and non-instrumented areas with a low accumulation of debris.

Direct bonded space maintainer: an alternative in clinical practice after unilateral premature loss of posterior primary tooth

Introduction: The primary dentition is extremely important, because besides the importance during chewing, acts as a guide to eruption for permanent teeth, stimulates the bone growth and helps in digestion and phonation. In cases of premature loss, it is necessary that the professional make adequate planning to space maintenance, so that it is not lost until the eruption of the permanent successor, thus avoiding the establishment of malocclusions. Objective: To describe the clinical steps for preparation and placement of a direct bonded space maintainer, as well as the follow-up until the eruption of the successor tooth. Case report: Girl, eight years old, presented an adjacent fistula to theprimary mandibular right second molar. After clinical and radiographic evaluation, tooth extraction was indicated, due to the impossibility of performing the endodontic treatment. A direct bonded space maintainer was made and installed as an alternative to the band and loop, commonly used in these cases of unilateral loss. Conclusion: The direct bonded space maintainer was a good option for the case presented, as it was able to fulfill its function until the eruption of the successor tooth. It is a good alternative in clinical practice due to the time optimization and material savings it provides.

Introdução: A dentição decídua é de extrema importância, pois exerce função mastigatória, atua como guia de erupção para os dentes permanentes, estimula o crescimento ósseo e auxilia na digestão e fonação. Em casos de perda prematura de algum dente, é necessário que o profissional faça um planejamento adequado para manutenção do espaço, de forma que este não seja perdido até a erupção do sucessor permanente, evitando assim o estabelecimento de más-oclusões. Objetivo: Descrever as etapas clínicas para confecção e instalação do aparelho mantenedor de espaço adesivo, bem como o acompanhamento até a erupção do sucessor. Relato do caso: Menina, 8 anos, apresentou fístula adjacente ao segundo molar inferior direito decíduo. Após avaliação clínica e radiográfica, foi indicada a exodontia do dente, devido à impossibilidade de realizar o tratamento endodôntico. Confeccionou-se e instalou-se o aparelho mantenedor de espaço adesivo, como uma alternativa ao banda-alça, comumente utilizado nesses casos de perda unilateral. Conclusão: O mantenedor de espaço colado foi uma boa opção para o caso apresentado, pois foi capaz de cumprir sua função até a erupção do dente sucessor, constituindo-se uma boa alternativa na prática clínica, devido à otimização do tempo e economia de material que proporciona.

Instrumentação mecanizada no tratamento endodôntico de incisivos centrais superiores decíduos: estudo em micro-ct utilizando protótipos / Mechanized instrumentation for endodontic treatment in primary maxillary central incisors: micro-ct study using prototypes

O objetivo deste trabalho foi avaliar o resultado do preparo biomecânico da instrumentação endodôntica em protótipos de dentes decíduos intactos com sistemas mecanizados através de microtomografia computadorizada. Foram utilizados 50 protótipos de um incisivo central superior decíduo produzido através de impressão 3D. Os sistemas de limas empregados foram o manual (MN), WaveOne Gold (WOG), XP Endo Shaper (XPS), XP Endo Finisher (XPF) e XP Clean (XPC). Cada grupo contou com 10 dentes e foram instrumentados de acordo com as recomendações dos fabricantes. O escaneamento dos protótipos pelo micro-CT foi realizado antes e após a instrumentação e as reconstruções foram padronizadas para cada conjunto de imagens. O teste de Shapiro-Wilk foi utilizado para verificar a normalidade dos dados. O ANOVA seguido do teste de Tukey foi utilizado para comparar as médias de volume final do canal, formação de debris, volume de dentina removida e área não instrumentada das paredes do canal. O teste T de Student foi usado para comparar os volumes inicial e final do canal entre cada grupo de instrumentação. A presença de trincas e/ou perfurações ao longo do canal foi registrada e realizada uma descrição qualitativa da sua presença. Todos os grupos apresentaram uma diferença significativa no volume do canal após a instrumentação. O maior aumento de volume do canal foi com as limas manuais, que teve uma diferença estatística significativa quando comparado com os rotatórios, que não apresentaram diferença entre si. Em relação ao acumulo de debris e aréas não tocadas não houve diferença estatística entre os grupos. O maior volume de dentina removido foi quando utilizado as limas manuais. Apenas os grupos manual e WOG apresentaram trincas. Perfuração radicular foi observado apenas no grupo manual. Concluimos que o uso de sistemas rotatórios apresentou melhores resultados no preparo biomecânico do canal de incisivos superiores decíduos quando comparado à limas manuais. O sistema XP Clean combinou bons resultados, com pouco acumulo de debris e maior área tocada pelo instrumento no interior do canal. (AU)

The aim of this study was to evaluate the result of biomechanical preparation of endodontic instrumentation in prototypes of intact primary teeth with mechanized systems using computerized microtomography. 50 prototypes of a primary maxillary central incisor produced using 3D printing were used. The file systems used were hand files, WaveOne Gold (WOG), XP-Endo Shaper (XPS), XP-Endo Finisher (XPF) and XP Clean (XPC). Each group had 10 teeth and were instrumented according to the manufacturers' recommendations. The scanning of the prototypes by micro-CT was performed before and after instrumentation and the reconstructions were standardized for each set of images. The Shapiro-Wilk test was used to verify the normality of the data. ANOVA followed by the Tukey test was used to compare the averages of final canal volume, debris formation, dentin volume removed and untouched area of the canal walls. Student's t-test was used to compare the initial and final volumes of the canal between each instrumentation group. The presence of cracks and / or perforations along the canal was recorded and a qualitative description was made. All groups showed a significant difference in volume of the canal after instrumentation. The greatest increase in volume of the canal was with hand files, which had a statistically significant difference when compared to rotary files, which showed no difference among them. Regarding the accumulation of debris and noninstrumented areas, there was no statistical difference between the groups. The largest volume of dentin removed was when using hand files. Only the hand files and WOG groups showed cracks. Root perforation was observed only in the hand file group. We concluded that the use of rotary systems showed better results in the biomechanical preparation of the canal of primary maxillary incisors when compared to hand files. The XP Clean system combined good results, with little debris accumulation and a larger area played by the instrument inside the canal. (AU)