Impact of radiotherapy on the morphological and compositional structure of intra-radicular dentin.

Considering the side effects in the oral cavity and dental structures of radiotherapy (RDT) for head and neck cancer, this study aimed to evaluate the effects of RDT on the root dentin concerning the obliteration of dentinal tubules, the inorganic composition of intra-radicular dentin, and the integrity of collagen fibers. Thirty human canines were selected from a biobank and randomly divided into two groups (n=15). The samples were sectioned buccolingually, and a hemisection was used for structural analysis by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometer (EDS). Low-vacuum SEM images were obtained at 2000-x magnification to observe the obliteration of the dentinal tubules. Moreover, compositional evaluation was performed using EDS. After RDT, the SEM and EDS analyses were repeated using the same methodology. RDT was applied fractionally at 2 Gy per day, 5 days per week, for 7 weeks, resulting in a total dose of 70 Gy. The collagen integrity of the irradiated and non-irradiated samples was analyzed using Masson's trichrome and picrosirius red staining polarization microscopy. Samples subjected to RDT exhibited dentinal tubule obliteration (p < 0.001); low integrity of type I and III collagen fibers (p < 0.05); compositional reduction of calcium (p = 0.012), phosphorus (p = 0.001), and magnesium (p < 0.001); an increased Ca/P ratio (p < 0.001). RDT affects the structure of dentinal tubules, the inorganic composition of intra-radicular dentin, and the collagen fiber integrity in the root dentin, which may interfere with the effectiveness and durability of dental procedures.

Impact of radiotherapy on the morphological and compositional structure of intra-radicular dentin

Abstract Considering the side effects in the oral cavity and dental structures of radiotherapy (RDT) for head and neck cancer, this study aimed to evaluate the effects of RDT on the root dentin concerning the obliteration of dentinal tubules, the inorganic composition of intra-radicular dentin, and the integrity of collagen fibers. Thirty human canines were selected from a biobank and randomly divided into two groups (n=15). The samples were sectioned buccolingually, and a hemisection was used for structural analysis by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometer (EDS). Low-vacuum SEM images were obtained at 2000-x magnification to observe the obliteration of the dentinal tubules. Moreover, compositional evaluation was performed using EDS. After RDT, the SEM and EDS analyses were repeated using the same methodology. RDT was applied fractionally at 2 Gy per day, 5 days per week, for 7 weeks, resulting in a total dose of 70 Gy. The collagen integrity of the irradiated and non-irradiated samples was analyzed using Masson's trichrome and picrosirius red staining polarization microscopy. Samples subjected to RDT exhibited dentinal tubule obliteration (p < 0.001); low integrity of type I and III collagen fibers (p < 0.05); compositional reduction of calcium (p = 0.012), phosphorus (p = 0.001), and magnesium (p < 0.001); an increased Ca/P ratio (p < 0.001). RDT affects the structure of dentinal tubules, the inorganic composition of intra-radicular dentin, and the collagen fiber integrity in the root dentin, which may interfere with the effectiveness and durability of dental procedures.

Resumo Considerando os efeitos colaterais na cavidade oral e estruturas dentárias da radioterapia (RDT) para o câncer de cabeça e pescoço, este estudo teve como objetivo avaliar os efeitos da RDT sobre a dentina radicular quanto à obliteração dos túbulos dentinários, a composição inorgânica da dentina intra-radicular e a integridade das fibras colágenas. Trinta caninos humanos foram selecionados de um biobanco e divididos aleatoriamente em dois grupos (n=15). As amostras foram seccionadas no sentido vestíbulo-lingual, e uma hemissecção foi utilizada para análise estrutural por microscopia eletrônica de varredura (MEV) e espectrômetro de raios X de dispersão de energia (EDS). Imagens de MEV de baixo vácuo foram obtidas com aumento de 2500x para observar a obliteração dos túbulos dentinários. Além disso, a avaliação composicional foi realizada usando EDS. Após a RDT, as análises em MEV e EDS foram repetidas usando a mesma metodologia. A RDT foi aplicada fracionada a 2 Gy por dia, 5 dias por semana, durante 7 semanas, resultando em uma dose total de 70 Gy. A integridade do colágeno das amostras irradiadas e não irradiadas foi analisada usando microscopia de polarização de coloração com tricrômio de Masson e picrosirius red. As amostras submetidas a RDT apresentaram obliteração dos túbulos dentinários (p < 0,001); baixa integridade das fibras colágenas tipo I e III (p < 0,05); redução composicional de cálcio (p = 0,012), fósforo (p = 0,001) e magnésio (p < 0,001); e uma relação Ca/P aumentada (p < 0,001). A RDT afeta a estrutura dos túbulos dentinários, a composição inorgânica da dentina intra-radicular e a integridade das fibras colágenas na dentina radicular, o que pode interferir na eficácia e durabilidade dos procedimentos odontológicos.

Prevalence of dental alterations in patients under bisphosphonates therapy: a systematic review.

This systematic review aimed to estimate the prevalence and describe dentoalveolar lesions associated with bisphosphonates therapy. A systematic review of the literature was conducted using the following databases: PubMed, Embase, Cochrane, CINAHL, Scopus, Web of Science, Lilacs, SciElo, and Grey Literature. Quality of individual studies analysis was performed by using Newcastle-Ottawa Scale. Certainty of cumulative evidence was achieved by applying Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria. The software R Statistics version 4.0.5 (The R Foundation) was used for proportion estimations per study and corresponding confidence intervals were estimated through the Clopper-Pearson method. Four articles were included for the qualitative synthesis. Two studies were considered of good quality, one of fair, and one of poor quality. A total of 231 patients were encompassed. Widening of the periodontal ligament space (22.2-39.7%), periradicular radiolucencies (20-22.9%), and pulp calcifications (33.3-69.2%) were the most frequent alterations. Certainty of evidence was rated as very low. Based on limited evidence, this systematic review reports a variety of dentoalveolar alterations in patients under bisphosphonate therapy. These features might impact on dental clinical practice. However, the level of evidence is considered very low due to important limitations.

A influência de diferentes métodos de ampliação cervical na obtenção do comprimento de trabalho em canais mesiovestibulares de primeiros molares superiores / The influence of different methods of cervical magnifying in the attainment of the lenght of work in first mesio-vestibular canals tests of superior molar

A ampliação da entrada de canais radiculares com o uso de diferentes tipos de métodos e instrumentos é alvo de inúmeras pesquisas na Odontologia. O objetivo deste estudo foi determinar a influência de quatro sistemas distintos de instrumentos rotatórios para alargamento cervical na determinação do comprimento real de trabalho (CRT). Por meio da comparação entre esses quatro tipo de instrumento diferentes que podem ser utilizados pelo profissional, averiguou-se o mais efetivo para a ampliação cervical de canais radiculares curvos. A etapa experimental foi realizada no Laboratório de Endodontia da Faculdade de Odontologia da Universidade de Passo Fundo (FOUPF). O estudo in vitro foi feito com 40 raízes mesiovestibulares de primeiros molares superiores humanos permanentes, obtidas no banco de dentes da FOUPF. As 40 amostras foram divididas aleatoriamente em 4 grupos de 10 dentes cada, os quais foram submetidos ao acesso endodôntico convencional. Após a verificação do CRT, aplicaram-se os métodos de ampliação cervical em cada grupo, com uso de brocas Gates-Glidden (Dentsply Maillefer, Ballaigues, Suíça) no grupo 1, alargadores rotatórios de níquel-titânio Orifice Openers (SybronEndo, Glendora, USA) no grupo 2, instrumentos de níquel-titânio SX e o instrumento S1 (ProTaper ­ Dentsply Maillefer, Ballaigues, Suíça) no grupo 3 e LA Axxess (SybronEndo, Glendora, USA) no grupo 4. Na seqüência verificou-se novamente o CRT. A diferença entre a primeira e a segunda odontometria foi calculada (ANOVA), e o teste de comparações múltiplas de Tukey (p ≤ 5%) identificou diferenças significativas entre os grupos avaliados. Os instrumentos rotatórios de níquel-titânio SX e S1 do sistema ProTaper apresentaram os melhores resultados, e os instrumentos rotatórios de aço inox Gates-Glidden (brocas) tiveram os piores resultados

The magnifying of radicular canals using different types of methods and instruments is focus of innumerable researches in Deontology. The objective of this study was to determine the influence of four distinct systems of rotatory instruments for cervical widening in the determination of the real length of work (CRT). Through the comparison among these four types of possible different instruments to be used by the professional it was possible to evaluate the most effective for the cervical magnifying of arched radicular canals. The experimental stage was carried through in the Laboratory of Endodontia of the College of Odontologia of the University of Passo Fundo (FOUPF). The present in vitro study involved 40 roots of first mesio-vestibular tests of molar permanent human superiors, gotten in the Tooth Bank of the College of Odontologia of the University of Passo Fundo (FOUPF). The 40 samples have been divided randomly in 4 groups of 10 teeth each, which have been submitted to the conventional endodontic access. After the verification of the real CRT, the methods of cervical magnifying in each group have been applied, being group 1 with Gates-Glidden drills (Dentsply Maillefer, Ballaigues, Switzerland), group 2 with rotatory nickel-titanium wideners ORIFICE OPENERS (SybronEndo, Glendora, the USA), group 3 with nickel-titanium instruments SX and the S1 instrument (ProTaper - Dentsply Maillefer, Ballaigues, Switzerland), and group 4 with LA Axxess (SybronEndo, Glendora, USA). After that the CRT was verified again. The difference between the first and the second odontometry has been calculated (ANOVA) and the test of multiple comparisons of Tukey (p ≤ 5%) identified significant differences between the studied groups. The rotatory nickel-titanium instrument SX and S1 of the ProTaper system has presented the best results and the rotatory steel instruments inox Gates Glidden (drills) have presented the worst ones