ABSTRACT
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.
ABSTRACT
Abstract The aim of this study was to evaluate the immunohistochemical expression of receptor activator of nuclear factor kappa-B ligand (RANKL) and of osteoprotegerin (OPG), important proteins correlated with osteoclastogenesis, in central giant cell lesions (CGCL) and peripheral giant cell lesions (PGCL) and to compare their expression with the histological and clinical parameters for quantification of multinucleated giant cells (MGC) and their nuclei, lesion size, and recurrences. Twenty cases of each lesion type were selected to quantify the number of MGCs and nuclei/mm2 of connective tissue. The immunoreactivity of RANKL and OPG was expressed as a percentage of the marked area in the stroma. Clinical data were collected from pathoanatomical and medical reports. No statistical differences were found for the number of MGCs (p = 0.24) between PGCL and CGCL, but the number of nuclei within the MGCs was higher in CGCL (p = 0.01). RANKL expression was higher in CGCL than in PGCL (p = 0.04) and all recurrent lesions showed higher RANKL and OPG expressions than nonrecurrent lesions. We report higher RANKL expression and a greater number of nuclei in CGCL, which may explain the difference in clinical behaviour between these lesions and their pathogenesis.
Subject(s)
Humans , Male , Female , Adolescent , Adult , Middle Aged , Young Adult , Granuloma, Giant Cell/pathology , Jaw Diseases/pathology , Giant Cells/pathology , RANK Ligand/analysis , Osteoprotegerin/analysis , Reference Values , Immunohistochemistry , Predictive Value of Tests , Retrospective Studies , Statistics, Nonparametric , Middle AgedABSTRACT
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