Smear layer influence on the apical seal of four different obturation techniques

The purpose of this study was the in vitro evaluation of four techniques for the obturation of the root canal system in the presence or absence of a smear layer. Ninety-six human upper central incisors were instrumented using the pressureless crown-down technique and irrigated with 5.25% NaOCl. The teeth that had the smear layer removed were irrigated with this solution in combination with 17% EDTA. The teeth were obturated with lateral condensation with an accessory or standardized cone as the main cone, with vertical condensation of warm gutta-percha or with thermoplasticized injectable gutta-percha. Apical leakage was assessed by measuring the linear penetration of methylene blue dye with a stereomicroscope. The results showed no significant differences in the degree of leakage with and without the smear layer when the samples were considered as a whole. However, when the groups were assessed separately, teeth in the lateral condensation with an accessory main cone group and teeth in the thermoplasticized group leaked less with a smear layer present. In contrast teeth with lateral condensation and a standardized main cone leaked more with a smear layer present. In the vertical condensation groups there was no difference attributable to the smear layer.     

Biocompatibility of sealers used in apical surgery: a histological study in rat subcutaneous tissue

The aim of this study was to evaluate the biocompatibility of sealers used in apical surgery in rat subcutaneous tissue. Sterile polyethylene tubes were filled with the following sealers: Sealapex, Sealapex with addition of zinc oxide, Sealer 26, Sealer 26 with thicker consistency (greater powder-to-resin ratio) and White MTA. The tubes were implanted in the dorsum of male rats and after 7, 21 and 42 days, the animals were killed, obtaining 5 specimens for each sealer in each evaluation period. The lateral surface of the tube was used as negative control. The inflammatory reaction to contact with the sealers was classified as absent, mild, moderate and severe. At 7 days, all sealers caused similar inflammatory reactions in the connective tissue of the animals, with most specimens presenting a moderate to intense chronic inflammatory reaction, with presence of multinucleated giant cells. At 21 days, Sealer 26 and Sealer 26 with thicker consistency presented more intense inflammatory reaction (p=0.004), whereas after 42 days, the inflammatory reaction ranged from absent to mild with statistically similar results for both materials (p=0.08). Except for MTA, all sealers presented foreign-body granulomatous reaction at 42 days. All sealers but Sealapex presented a statistically significant decrease of the inflammatory reaction over time. In conclusion, all sealers caused moderate to severe inflammation in the earlier evaluation period. However, Sealer 26 and Sealer 26 with thicker consistency caused more intense inflammatory reactions after 21 days of contact with the tissues and no granulomatous reaction was observed for MTA at the final period of analysis.     

The limited value of three pathogen species in predicting healing of periodontal pockets

Baseline level of Actinobacillus actinomycetemcomitans has been suggested as being predictive of periodontal treatment outcome. We analyzed the presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia in 55 deep periodontal pockets of 29 patients (18 men, 11 women, 37-75 years) before and after periodontal treatment. At baseline and after treatment, 62% and 33%, respectively, of the subjects presented with 1, 2, or a combination of all 3 pathogens. The mean pocket depth of 6.6 mm (0.4 mm) before treatment decreased to 2.2 mm (0.4 mm) in response to treatment (P<0.001). The treatment plan of non-surgical or surgical treatment was based on pocket depths and tooth morphology only. No antimicrobial medications were used during the treatment. Eighty-two percent of the deep pockets healed satisfactorily to < or = 4 mm. The presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, or Prevotella intermedia at baseline was not associated with the outcome of the periodontal therapy. In conclusion, we found that the presence of the 3 periodontopathogen species had little or no value in predicting healing of periodontal pockets.     

Comparative study on mineralization-related intraoral parameters in periodontitis-affected and periodontitis-free adults

The parameters related to an intraoral mineralization tendency in periodontitis-affected (P+) and periodontitis-free (P-) study subjects (16 adults, 46-74 yr, matched for sex and age) were compared. For this purpose the calcium (Ca) and phosphate (P) concentration of both plaque and saliva, resting pH and the acidogenic response of interdental plaque, plaque wet weight, salivary flow rate, buffering capacity and sucrase activity, interdental plaque, plaque S. mutans levels as well as salivary lactobacilli and yeast levels were estimated. Plaque Ca (micrograms/mg protein, P less than 0.025) and P (micrograms/mg protein, P less than 0.05), saliva Ca (micrograms/ml, P less than 0.005) and the saliva Ca:P ratio (P less than 0.005) were higher in the P+ than in the P- group. The resting pH values were higher (P less than 0.025) and the acidogenic response of the interdental plaque was lower (P less than 0.025) in the P+ group than in the P- group. The P+ group had lower S. mutans levels in saliva and interdental plaque. No differences were found in the wet weight of plaque and in the flow rate, buffering capacity or sucrase activity of saliva between the groups. The findings of the mineralization-related parameters in the two "extreme" groups of periodontal status suggest a higher intraoral mineralization tendency in periodontitis-affected persons than in periodontitis-free subjects. Ca and P accumulation of supragingival plaque seem to be connected with low acidogenicity of plaque and high salivary Ca concentration.     

Literature survey of apexification in connection with three cases

Endodontic treatment of three non-vital immature teeth is discussed. According Moorrees et al. root formation was in the stage two, six and four respectively. After access to the root canal, removing necrotic pulp and effective chemo-mechanical cleansing, Ca(OH)2 paste was used as a temporary filling material in each case. In two cases after closing the apical opening, permanent obturation was performed with half heated gutta-percha and lateral condensation to obtain a good seal. In one case permanent filling of the canal occurred with gutta-percha and AH26 as a sealer. In the first case two years, in the second case five years after obturation of the root canal with gutta-percha, periapical healing was evident in the control radiograph. In the third case using gutta-percha with AH26 as a sealer after two years new periapical lesion has developed. On the bases of literature data and our experiences in the case of non-vital immature teeth. Ca(OH)2 paste is the best temporary filling material to induce apexification process, and the half heated gutta-percha obturation is the most suitable permanent root filling material.     

Tissue destruction in periodontitis: bacteria or cytokines fault?

The pathogenesis of periodontal disease involves the sequential activation of a great variety of components of the host immune response, primarily acting to defend periodontal tissues against bacterial aggression, but also functioning as mediators of tissue destruction. The expression of the disease results from the interaction of host, microbiological agents, and environmental factors. Leukocytes play a critical role in the pathogenesis of the disease, producing different cytokines, chemokines, and other mediators, thus generating a host defense response, as well as inducing tissue inflammation and bone destruction. The aim of this review is to address the role of some inflammatory mediators in response to bacterial aggression in periodontitis.     

Study of the vascular pattern in oral lichen planus

Oral Lichen Planus is a relatively frequent disease. Its etiopathogenesis is still unknown and it can undergo malignant transformation during its evolution. Thus, data which could contribute to the knowledge of the biology of this disease are particularly significant. The present study involves a quantitative evaluation of the vascular pattern of oral lichen planus. A portion of biopsy specimens taken for histopathologic diagnosis was processed to mark vascular walls using the histoenzymic technique for ATPase activity demonstration. Stained Sections were then evaluated in a semi-automatic magnetic image analyser. The stereologic parameters studied, showed there is no vascular increase in lichen with regard to normal mucosae or leukoplakias, since the number of vascular walls did not show significant differences. Instead, a significant increase was observed in the vascular area. The association of these parameters, indicates that lichen is a more congestive lesion than the other two conditions studied. These findings indicate that the modifications of the vascular pattern could play a role in the etiopathogenesis of oral lichen planus and suggest that the observation of these changes could be a useful element in the histopathologic diagnosis.