Morphologic Changes of Apical Foramen and Microcrack Formation after Foraminal Enlargement: A Scanning Electron Microscopic and Micro-computed Tomographic Analysis.

INTRODUCTION: The aim of the present study was to evaluate the morphologic changes on the apical foramen and the formation of dentinal microcracks after foraminal enlargement in straight and curved root canals using scanning electron microscopic (SEM) and micro-computed tomographic (micro-CT) analyses. METHODS: Sixty teeth were selected and divided into 2 experimental groups: GI (incisors/straight group, n = 30) and GM (molars/curved group, n = 30). Each group was divided into 2 subgroups (n = 15) according to the analysis performed: SEM or micro-CT analysis. The incisors and mesiobuccal canal of molars were instrumented with Reciproc Blue R25 instruments (VDW, Munich, Germany) using standardized shaping procedures in the apical foramen and 1 mm beyond. The occurrence of foraminal deformation was analyzed by scanning electron microscopy. The z test was used for statistical analysis (P < .05). Micro-CT imaging was used to observe the presence of microcracks in the root apical third. Afterward, pre- and postoperative cross-sectional images were screened to identify the presence of dentinal defects. RESULTS: The curvature of the canal did not influence the occurrence of foraminal deformation either for instrumentation in the foramen or for instrumentation beyond the foramen (P > .05). It was also observed that the increase in the working length did not influence the appearance of new deformations in the GI/SEM and GM-SEM groups (P > .05). Qualitative micro-CT analysis showed the presence of dentinal defects in 0.8% (112) and 1.5% (208) of the cross sections of incisors and molars, respectively, from a total of 13,987 slices. All dentinal defects identified in the analysis of any postoperative scans were already present in the corresponding preoperative images. Therefore, no new microcracks were observed after root canal preparation. CONCLUSIONS: The preparation of straight and moderately curved root canals with Reciproc Blue, regardless of the working length, did not influence the occurrence of apical foramen deformations and did not cause the formation of dentinal microcracks.

Natural enamel caries, dentine reactions, dentinal fluid and biofilm.

It is believed that penetration of dentinal fluid into natural enamel caries (NEC) is negligible because of the barrier created by underlying sclerotic dentine, but there are conflicting evidences on whether dentine subjacent to NEC is sclerotic or demineralized. This study aimed at investigating the relationship between NEC, subjacent dentine reactions, modification of dentinal fluid, and composition of cariogenic biofilm formed on the NEC surface. Proximal NEC (PNEC) lesions of human permanent posterior teeth were included in five experiments. Histologically, microradiographic analysis with contrast solution (MRC) in dentine revealed a decreased proportion of sclerotic dentine and an increased proportion of deep dentine demineralization compared to the classical stereomicroscopic histological analysis based on dentin color and translucency. Real-time MRC and 3D optical profilometry, and 3D microtomographic analysis evidenced a facilitated transport of modified dentinal fluid towards PNEC lesions. Cariogenic biofilm formed in vitro on the PNEC surface presented lower amounts of insoluble and soluble matrix polysaccharides when 2% chlorexidine was inserted in the pulp chamber. In conclusion, this study evidenced that dentine subjacent to PNEC is mostly demineralized, providing facilitated pathway for dentinal fluid to penetrate into PNEC and alter the composition of the biofilm formed on the PNEC surface.

Correction: Correlation between ICDAS and histology: Differences between stereomicroscopy and microradiography with contrast solution as histological techniques.

[This corrects the article DOI: 10.1371/journal.pone.0183432.].

Correlation between ICDAS and histology: Differences between stereomicroscopy and microradiography with contrast solution as histological techniques.

Detection of occlusal caries with visual examination using ICDAS correlates strongly with histology under stereomicroscopy (SM), but dentin aspects under SM are ambiguous regarding mineral content. Thus, our aim was to test two null hypotheses: SM and microradiography result in similar correlations between ICDAS and histology; SM and microradiography result in similar positive (PPV) and negative predictive values (NPV) of ICDAS cut-off 1-2 (scores 0-2 as sound) with histological threshold D3 (demineralization in the inner third of dentin). Occlusal surfaces of extracted permanent teeth (n = 115) were scored using ICDAS. Undemineralized ground sections were histologically scored using both SM without contrast solution and microradiography after immersion in Thoulet's solution 1.47 for 24 h (MRC). Correlation between ICDAS and histology differed from SM (0.782) to MRC (0.511) (p = 0.0002), with a large effect size "q" of 0.49 (95% CI: 0.638/0.338). For ICDAS cut-off 1-2 and D3, PPV from MRC (0.56) was higher than that from SM (0.28) (p< 0.00001; effect size h = 0.81), and NPV from MRC (0.72) was lower than that from SM (1,00) (p < 0.00001; effect size h = 1.58). In conclusion, SM overestimated the correlation between ICDAS and lesion depth, and underestimated the number of occlusal surfaces with ICDAS cut-off 1-2 and deep dentin demineralization.

Abordagem sistêmica do pênfigo vulgar com acometimento oral / Systemic approach of the vulgar penfigure with oral accomplishment

O termo "pênfigo" remete a um grupo de doenças autoimunes raras, caracterizadas pela formação de bolhas, que afetam o epitélio escamoso estratificado da pele, mucosa ou ambos. Cinco tipos principais de pênfigo foram descritos: vulgar (PV), vegetante, eritematoso, foliáceo e paraneoplásico. O PV é a variante mais comum e frequentemente acomete a mucosa oral. Este artigo relata um caso de Pênfigo Vulgar, com acometimento da mucosa oral e com 10 anos de evolução. Paciente de gênero masculino, 70 anos, procurou o serviço, queixando-se de úlceras na mucosa que causavam ardência e não cicatrizavam. Foi realizada uma biópsia incisional da lesão e, após exame histopatológico, estabelecido o diagnóstico de PV, sendo instituído um regime terapêutico com 60 mg de prednisona por via oral, até a remissão dos sintomas. O PV é uma doença sistêmica de caráter imunológico, de grande importância para a odontologia, tendo em vista que geralmente as manifestações orais antecedem as sistêmicas. Essa doença não tem cura, mas pode ser controlada, como no referido caso. Embora o diagnóstico nesse caso não tenha sido precoce, o prognóstico foi favorável... (AU)

The term "pemphigus" refers to a group of rare autoimmune diseases, characterized by the formation of blisters that affect the squamous epithelium stratified of the skin, oral mucosa or both. Five main types of pemphigus were described: pemphigus vulgaris (PV), vegetative, erythematous, foliaceous and paraneoplastic pemphigus. PV is a more common variant and often affects an oral mucosa. This article reports a case of Pemphigus vulgaris, with involvement of the oral mucosa and 10 years of evolution. A male patient, 70 years old, sought the service complaining of ulcers in the mucosa that caused burning and did not heal. An incisional biopsy of the lesion was performed and after histopathological examination, the diagnosis of PV was established, a therapeutic regimen with oral prednisone 60 mg was instituted util remission of symptoms. PV is a systemic disease of immunological character that has great importance for dentistry, since oral manifestations usually precede the systemic ones. This disease has no cure, can be controlled, as in this case, although the diagnosis in this case was not early, the prognosis was favorable... (AU)