Irrigation of the root canal systems is an extremely important step in root canal treatment. Therefore, it is of relevance to evaluate the efficacy of these systems by in vivo experimental models to provide scientific background for the clinical practice.

Mucocele is a benign lesion occurring in the buccal mucosa as a result of the rupture of a salivary gland duct and consequent outpouring of mucin into soft tissue. It is usually caused by a local trauma, although in many cases the etiology is uncertain. Mucocele is more commonly found in children and young adults, and the most frequent site is the lower inner portion of the lips. Fibroma, on the other hand, is a benign tumor of fibrous connective tissue that can be considered a reactionary connective tissue hyperplasia in response to trauma and irritation. They usually present hard consistency, are nodular and asymptomatic, with a similar color to the mucosa, sessile base, smooth surface, located in the buccal mucosa along the line of occlusion, tongue and lip mucosa. Conventional treatment for both lesions is conservative surgical excision. Recurrence rate is low for fibroma and high for oral mucoceles. This report presents a series of cases of mucocele and fibroma treated by surgical excision or enucleation and the respective follow-up routine in the dental clinic and discusses the features to be considered in order to distinguish these lesions from each other. M u c o c e l e a n d F i b r o m a : Treatment and Clinical Features

In this laboratory study, the iPex accurately identified the apical foramen or the apical opening location for working length measurement in primary molar teeth.

The aim of this study was to evaluate if apical negative pressure (ANP) irrigation prevents the apical extrusion of debris and irrigant compared with conventional needle irrigation through a systematic review and meta-analysis. A computer search of dental literature was performed using four different databases. A combination of the terms 'apical negative pressure', 'endovac', 'apical extrusion', 'extrusion' and 'endodontics' was used. Studies that used extracted human teeth with a mature apex and that evaluated the apical extrusion of debris and/or irrigating solution were included. After an evaluation of the full studies according to the eligibility criteria, eight studies were critically analysed and subjected to quality assessment and risk of bias. Only four studies that evaluated extrusion of irrigant were considered as having high methodological quality and were subjected to a meta-analysis. Studies evaluating extrusion of debris did not have sufficient methodological quality to be subjected to the meta-analysis. The forest plot indicated that ANP irrigation prevents the risk of irrigant extrusion compared with conventional irrigation (OR 0.07 [95%CI 0.02-0.20]; P < 0.00001). This systematic review and meta-analysis showed that ANP prevents the apical extrusion of irrigant. There is no evidence if this type of irrigation prevents the extrusion of debris.

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Aim To evaluate the effect of alendronate (ALN) on the development of periapical lesions induced in ovariectomized rats. Methodology Twenty‐five rats were divided into three groups: sham (control), ovariectomy (OVX) and OVX + ALN. One day after OVX, animals from the OVX + ALN group received the medication via gavage. After 9 weeks, the first molars of all animals were submitted to periapical lesion induction. After 21 days, the animals were euthanized. Femurs were analysed for bone mineral density. The blocks of bone tissue containing the mandibular first molars were submitted to histotechnical processing and staining with haematoxylin and eosin (HE) for periapical lesion analysis under conventional microscopy. At the same time, the morphometric analysis of the periapical lesion area was performed in the fluorescence mode, as well as the histoenzimology for the quantification of osteoclasts and 4′‐6‐diamidino‐2‐phenylindole staining for the quantification of apoptotic osteocytes. In addition, the first maxillary molars were used for analysis of the gene expression of proinflammatory cytokines (IL‐1β, IL‐6 and TNF‐α) and osteoclastogenesis markers (RANKL/OPG). The results were submitted to ANOVA and Kruskal–Wallis tests and Tukey and Dunn post‐tests (significance level of 5%). Results Ovariectomy reduced bone mineral density of the femur, and treatment with ALN was able to prevent bone loss (P < 0.001). Regarding the microscopic analysis of the periapical region, the sham and OVX + ALN groups had moderately increased periodontal ligament and inflammatory infiltrate, while the OVX group had these parameters increased intensely. The periapical lesions of the OVX group were significantly larger in area in comparison to the other groups (P < 0.001). The OVX group had the largest amount of apoptotic osteocytes, and ALN was able to prevent the apoptosis of these cells, in addition to significantly reducing IL‐6 expression (P < 0.05). OVX and ALN had no effect on RANKL/OPG expression and did not influence the number of osteoclasts around the periapical lesion (P > 0.05). Conclusion The hypoestrogenic condition induced by OVX aggravated bone resorption, inducing the death of osteocytes and provoking larger periapical lesions. ALN treatment inhibited osteocyte apoptosis and inflammation via IL‐6, inhibiting bone resorption in periapical lesions of ovariectomized rats.

Bertasso AS, L eon JE, Silva RAB, Silva LAB, de Queiroz AM, Pucinelli CM, Romualdo PC, Nelson-Filho P. Immunophenotypic quantification of M1 and M2 macrophage polarization in radicular cysts of primary and permanent teeth.

Aim:To compare the apical negative pressure irrigation (ANP) with conventional irrigation in the teeth of immature dogs with apical periodontitis.Methods:Fifty-two immature pre-molar root canals were randomly assigned into 4 groups: ANP (n=15); conventional irrigation (n=17); healthy teeth (control) (n = 10); and teeth with untreated apical periodontitis (control) (n=10). After induction of apical periodontitis, teeth were instrumented using EndoVac® (apical negative pressure irrigation) or conventional irrigation. The animals were euthanized after 90 days. The sections were stained by HE and analyzed under conventional and fluorescence microscopy. TRAP histoenzymology was also performed. Statistical analyses were performed with the significance level set at 5%.Results:There was difference in the histopathological parameters between ANP and conventional groups (p<0.05). The ANP group showed a predominance of low magnitude inflammatory infiltrate, a smaller periodontal ligament, and lower mineralized tissue resorption. There were no differences in the periapical lesion extensions between the ANP and conventional groups (p>0.05). However, a lower number of osteoclasts was observed in the ANP group (p<0.05).Conclusion:The EndoVac® irrigation system presented better biological results and more advanced repair process in immature teeth with apical periodontitis than the conventional irrigation system, confirming the hypothesis.