Consideraciones clínicas sobre la resorción radicular externa por impactación dentaria

[email protected] resorción externa por presión (RREP) consiste en una pérdida de tejido dentinario y cementario de las raíces dentarias que se origina a nivel del ligamento periodontal, ocasionada por presiones prolongadas y mantenidas sobre la raíz. Presentamos tres casos con diferente repercusión y tratamiento. Según el distinto grado de afectación se describe y clasifica el tratamiento de RREP a causa de dientes impactados. En cuanto a la restauración de RREP se perfila la cavidad clase V de diseño 5 y el empleo de cermet o amalgamas de plata para su relleno.Pressure external root resorption (PERR) is a loss of dental root tissues (dentine and cementum) that begin in the periodontal area caused by a impacted teeth. We show three cases with differents clinical situations and therapeutical aspects. Pulpal injurie and difficulty in the post-endodontic cavity acces are characteristiques of these processes. Depending on the level of tissue destruction we discusse the therapeutical orientation in each case. Some treatments like class V type 5 cavities or fillings with cermet glass-ionomer in the more atipical situations (generally after an endodontic treatment) are a good choice in these [email protected] [email protected]

Effet de deux agents de blanchiment sur la surface de l’émail. Etude in vitro

We present a study «in vitro» of the effect of bleaching agents on dental surfaces using the «Walking bleaching technique». We found that hydrogen peroxide bleached more quickly than carbamide although, after a period of six weeks, the results were the same as far as wheitening was concerned. In the scanning electron microscope we observed significantly different changes in each case. Carbamide caused a regular and uniform opening of the enamel prisms of the surface while hydrogen peroxide produced more severe superficial destructuration with the appearance of patterning similar to the acid etching, and the presence of some crystalline areas emerging from the body of the prisms.Nous présentons une étude in vitro de l’effet sur la surface dentaire de deux agents de blanchiment utilisés par la technique «Walking bleaching». Nous observons que le peroxyde d’hydrogène blanchit plus vite que le peroxyde de carbamide même si dans un délai de 6 semaines les résultats sont les mêmes en ce qui concerne le blanchiment. Au MEB, nous observons des changements significativement différents dans l’un et l’autre cas. Le peroxyde de carbamide provoque une ouverture des prismes sur la surface de l’émail de manière régulière et uniforme, alors que le peroxyde d’hydrogène produit des destructurations superficielles plus importantes avec l’apparition d’un maître-modèle comme celui de mordançage acide avec la présence sur certaines zones de cristaux qui émergent du corps des prismes

The Prognosis of Root Canal Therapy: a 20-year Follow-up Ambispective Cohort Study on 411 Patients With 1169 Endodontically Treated Teeth

PURPOSE To evaluate the 20-year prognosis of endodontically treated/re-treated teeth in a population with multiple patient/tooth/site risk factors, and to investigate the prognostic factors that could predict the long-term outcome of endodontic therapy. MATERIALS AND METHODS This ambispective cohort study included patients who received primary/secondary root canal therapy from 1986 to 1998 performed by a single operator in a private practice. Outcomes measures were: tooth survival; clinical and radiographic success, as assessed by the treating clinician and an independent outcome assessor; and complications, as evaluated 20 years after treatment. Descriptive statisti-cs, life table and Cox regression analyses for survival were fitted. RESULTS Four hundred and eleven patients (59% affected by advanced periodontitis) with 1169 endodontically treated teeth were identified (703 treatment, 466 retreatment). Drop-outs at 20-year follow-up were 128 patients (31.1%) with 388 (33.2%) teeth. Forty teeth (3.4%) in 30 patients experienced endodontic complications, subsequently successfully treated. Clinical and radiographic evaluation revealed: complete clinical success in 542 teeth (69.7%), partial success in 10 (1.3%), partial failure in 75 (9.6%), and failure in 151 (19.4%) (10 extracted for endodontic reasons, 58 due to periodontitis, and 58 vertical fracture). Life table analysis revealed 86% tooth survival at 20-year follow-up. The chance of survival decreased with increasing patient age (P = 0.006). Re-treated teeth had better survival than treated teeth (P = 0.024) Canines and premolars had better chances of survival than incisors (P = 0.002 and P = 0.015, respectively). Teeth treated at two sittings (with intermediate medication) had reduced chances of survival as compared to teeth treated at one sitting (P = 0.027). Teeth treated for the first time for endodontic reasons exhibited a better chance of survival than teeth treated for periodontal and prosthetic reasons (P = 0.012). CONCLUSIONS The 20-year prognosis of endodontically treated/re-treated teeth as part of multidisciplinary rehabilitation of patients affected by advanced periodontitis is good. Aging, two-stage endodontic treatment, and endodontic treatment for non-endodontic reasons are important predictors of failure

Experimental strength of restorations with fibre posts at different stages, with and without using a simulated ligament

The aim of this study was to analyse the strength and failure mode of teeth restored with fibre posts under retention and flexural-compressive loads at different stages of the restoration and to analyse whether including a simulated ligament in the experimental setup has any effect on the strength or the failure mode. Thirty human maxillary central incisors were distributed in three different groups to be restored with simulation of different restoration stages (1: only post, 2: post and core, 3: post-core and crown), using Rebilda fibre posts. The specimens were inserted in resin blocks and loaded by means of a universal testing machine until failure under tension (stage 1) and 50º flexion (stages 2–3). Half the specimens in each group were restored using a simulated ligament between root dentine and resin block and the other half did not use this element. Failure in stage 1 always occurred at the post-dentine interface, with a mean failure load of 191·2 N. Failure in stage 2 was located mainly in the core or coronal dentine (mean failure load of 505·9 N). Failure in stage 3 was observed in the coronal dentine (mean failure load 397·4 N). Failure loads registered were greater than expected masticatory loads. Fracture modes were mostly reparable, thus indicating that this post is clinically valid at the different stages of restoration studied. The inclusion of the simulated ligament in the experimental system did not show a statistically significant effect on the failure load or the failure mode

Premolars restored with posts of different materials: fatigue analysis

Previous works studied the effect of the material and the dimensions of the post on the biomechanical performance (fracture strength and stress distribution) of restored teeth, under static loads. The aim of this work was to study the effect of the post material (glass fibre and stainless steel) on restored teeth, which have the final crown, under dynamic conditions. The use of a biomechanical model, including a fatigue analysis from FEA, is presented as a powerful method to study the effect of the material of the intraradicular post. The inclusion of the fatigue analysis allows for a more realistic study that takes into account the dynamic nature of masticatory forces. At the same time, the results obtained are easier to interpret by both dentists and mechanical engineers. No differences were found, with the load and number of cycles considered, between glass fibre and stainless steel as material for the intraradicular post used in premolars restorations

Chemical composition and bioactivity potential of the new endosequence BC Sealer formulación hiflow

Aim To evaluate in a laboratory setting the effects of Endosequence BC Sealer HiFlow (Brasseler USA, Savannah, GA, USA), a novel calcium silicate-based sealer developed for use in warm canal filling techniques, on human periodontal ligament stem cells (hPDLSCs). Methodology Eluates of EndoSequence BC Sealer HiFlow (BCHiF) (Brasseler USA), EndoSequence BC Sealer (BCS) (Brasseler USA) and AH Plus (AHP) (Dentsply DeTrey GmbH, Konstanz, Germany), were placed in contact with hPDLSCs. The characterisation of the chemical elements of the root canal sealers was assessed using Scanning Electron Microscopy and Energy Dispersive X-ray analysis (SEM-EDX). Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to determine the ion release of the sealers. MTT assay and wound healing techniques were used to determine cell viability and migration, respectively. Cell morphology and cell attachment were assessed using a direct contact technique of hPDLSCs onto the surface of the sealers and analysed by SEM. The bioactivity potential was carried out with the Alizarin Red and qPCR testing methods. The statistical differences were evaluated using one-way ANOVA and Tukey´s test (p0.05). Both BCS and BCHiF had similar rates of cell migration to the control group at 24 and 48 hours. Cell morphology and adhesion capacity were also similar for BCS and BCHiF groups, while the AHP group was associated with reduced adhesion capacity. The Alizarin Red assay revealed a significant difference between the BCS and the control group (p<0.001), as well as for the BCHiF group (p<0.001). Finally, BCS and BCHiF promoted overexpression of osteo/cementogenic genes. Conclusions In general, EndoSequence BC Sealer HiFlow possesses suitable biological properties to be safely used as a root canal filling material and promote increased expression of oste/cementogenic genes by hPDLSCs

Biological effeects of new hydraulic materials on human periodontal ligament stem cells

Abstract: Background: The aim of this study was: to evaluate the biological properties of new hydraulic materials: Bio-C Repair and Bio-C Sealer. Methods: Periodontal ligament stem cells were exposed to several dilutions of Bio-C Repair and Bio-C Sealer. The ion release profile and pH were determined. Metabolic activity, cell migration and cell survival were assessed using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), wound-healing assays and Annexin assays, respectively. Cells were cultured in direct contact with the surface of each material. These were then analyzed via scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). Statistical differences were assessed using a two-way ANOVA (α < 0.05). Results: Similar pH was observed in these cements. Bio-C Sealer released significantly more Ca and Si ions (p < 0.05) in comparison with Bio-C Repair. Undiluted Bio-C Sealer induced a significant reduction on cellular viability, cell survival and cell migration when compared to the control (p < 0.05). Moreover, SEM showed abundant cells adhered on Bio-C Repair and a moderate number of cells attached on Bio-C Sealer. Finally, EDX analysis identified higher percentages of Ca and O in the case of Bio-C repair than with Bio-C sealer, while other elements such as Zr and Si were more abundant in Bio-C sealer. Conclusions: Bio-C Repair displayed higher cell viability, cell adhesion and migration rates than Bio-C Sealer

Differential gene expression analysis provides new insights into the molecular basis of iron deficiency stress response in the citrus rootstock Poncirus trifoliata (L.) Raf.

Iron chlorosis is one of the major abiotic stresses affecting fruit trees and other crops in calcareous soils and leads to a reduction in growth and yield. Usual remediation strategies consist of amending iron to soil, which is an expensive practice, or using tolerant cultivars, which are difficult to develop when not available. To understand the mechanisms underlying the associated physiopathy better, and thus develop new strategies to overcome the problems resulting from iron deficiency, the differential gene expression induced by iron deficiency in the susceptible citrus rootstock Poncirus trifoliata (L.) Raf. have been examined. The genes identified are putatively involved in cell wall modification, in determining photosynthesis rate and chlorophyll content, and reducing oxidative stress. Additional studies on cell wall morphology, photosynthesis, and chlorophyll content, as well as peroxidase and catalase activities, support their possible functions in the response to iron deficiency in a susceptible genotype, and the results are discussed

NCAM (CD56) Expression in keratin-producing odontogenic cysts: aberrant expression in KCOT

Background: Keratin-producing odontogenic cysts (KPOCs) are a group of cystic lesions that are often aggressive, with high rates of recurrence and multifocality. KPOCs included orthokeratinised odontogenic cyst (OOC) and parakeratotic odontogenic cysts, which are now considered true tumours denominated keratocystic odontogenic tumours (KCOTs). GLUT1 is a protein transporter that is involved in the active uptake of glucose across cell membranes and that is overexpressed in tumours in close correlation with the proliferation rate and positron emission tomography (PET) imaging results. Methods: A series of 58 keratin-producing odontogenic cysts was evaluated histologically and immunohistochemically in terms of GLUT1 expression. Different data were correlated using the beta regression model in relation to histological type and immunohistochemical expression of GLUT1, which was quantified using two different morphological methods. Results: KPOC cases comprised 12 OOCs and 46 KCOTs, the latter corresponding to 6 syndromic and 40 sporadic KCOTs. GLUT1 expression was very low in OOC cases compared with KCOT cases, with statistical significant differences when quantification was considered. Different GLUT1 localisation patterns were revealed by immunostaining, with the parabasal cells showing higher reactivity in KCOTs. However, among KCOTs cases, GLUT1 expression was unable to establish differences between syndromic and sporadic cases. Conclusions: GLUT1 expression differentiated between OOC and KCOT cases, with significantly higher expression in KCOTs, but did not differentiate between syndromic and sporadic KCOT cases. However, given the structural characteristics of KCOTs, we hypothesised that PET imaging methodology is probably not a useful diagnostic tool for KCOTs. Further studies of GLUT1 expression and PET examination in KCOT series are needed to confirm this last hypothesis. Keywords: Glucose transporter protein, Immunohistochemistry, Keratin-producing odontogenic cyst, Keratocystic odontogenic tumour, Orthokeratinised odontogenic cyst, Positron emission tomograph