Radiographic examination of apical extrusion of root canal irrigants during cavitation induced by Er,Cr:YSGG laser irradiation: an in vivo study

Objectives

The purpose of the present study was to test the hypothesis that apical extrusion of the irrigant occurs during laser-driven irrigation in vivo.

Materials and methods

Three hundred human root canals, in 181 patients, were divided into two groups: the no lesion group (n?=?140) and the lesion group (n?=?160). All the root canals were enlarged using a crown down technique up to size 30–80 K-files, depending on the original condition of the root canal. For the final irrigation, the teeth were irrigated with a mixture of radiopaque contrast medium and NaOCl in solution. The solution was activated for 60 s in teeth with one canal or two canals and for 120 s in teeth with three or four canals.

Results

Radiopaque contrast medium was absent from the periapical tissues of all samples.

Conclusions

No contrast medium was observed radiographically in the periapical tissues. The hypothesis that apical extrusion of root canal irrigants occur during laser cavitation was rejected

Clinical relevance

It appears that the power of the laser used at 1 W for 1–2 min can drive the irrigation solution to the tip of the canal without harming the apical tissues.     

Effect of S-methylisothiourea,an inducible nitric oxide synthase inhibitor,in joint pain and pathology in surgically induced model of osteoarthritis

The aim of the present study was to evaluate in vivo modulatory effect of S-methylisothiourea (SMT), a preferential inhibitor of inducible nitric oxide synthase (iNOS) on pain and pathology in the surgical model of osteoarthritis (OA) in rats. The OA was produced by the anterior cruciate ligament transection (ACLT) and medial meniscectomy (MMx) of right knee. SMT was administered 1 day prior to the production of OA and continued up to day 42 postoperation. Mechanical hyperalgesia, thermal hyperalgesia, tail flick latency after repeated flexion and extension of OA knee and knee diameter of right knee were determined at weekly intervals. Serum levels of IL-1β, TNF-α and nitrite concentration were determined at the end of the experiment. Glycosaminoglycan (GAG) content, collagen content and histopathological evaluation of articular cartilage were also determined at the end of the experiment. SMT reduced mechanical hyperalgesia and the serum levels of IL-1β, TNF-α and nitrite. Further, SMT reduced the loss of GAG from articular cartilage. Microscopically, SMT reduced the severity of the cartilage lesion. The results indicate the effectiveness of SMT in attenuating the pain and pathology of experimental OA phase by reducing the production of nitric oxide and interleukin-1β and tumor necrosis factor-α, which are known to play a major role in the pathophysiology of OA.     

Matrix Metalloproteinase-9 (MMP-9) Expression in Different Subtypes of Ameloblastoma

Background

Ameloblastoma is a common benign odontogenic tumor of the jaw with a local invasive and highly destructive behavior and can develop in any age, with peak prevalence in 3rd–4th decade. Ameloblastoma can be divided into six histological types: follicular, plexiform, acanthomatous, desmoplastic, granular, and basal cell. Matrix metalloproteinase-9 (MMP-9) (92-kD gelatinase/type IV collagenases = gelatinase B) is involved in bone resorption by degradation of extracellular matrix and osteoclasts recruitment. Recent studies have found that MMP-9 is expressed by ameloblastoma and has a role in ameloblastoma local invasiveness.

Objective

To analyze MMP-9 expression between different histological types of ameloblastoma.

Material and Method

Forty samples of ameloblastoma were collected through consecutive sampling and the MMP-9 expression was detected using immunohistochemistry.

Result

All samples showed positive MMP-9 expression with moderate to strong intensity. 82.4 % plexiform type and 83.3 % mixed type have strong immunoexpression, significantly different with follicular type with only 36.4 % (P < 0.05).

Conclusion

Ameloblastoma plexiform and mixed type have higher MMP-9 expression than ameloblastoma follicular type. Different MMP-9 expression may contribute in different ameloblastoma biological behavior.     

Effective Range of FSSW Parameters for High Load-Carrying Capacity of Dissimilar Steel A283M-C/Brass CuZn40 Joints

In the current study, a 2 mm thick low-carbon steel sheet (A283M—Grade C) was joined with a brass sheet (CuZn40) of 1 mm thickness using friction stir spot welding (FSSW). Different welding parameters including rotational speeds of 1000, 1250, and 1500 rpm, and dwell times of 5, 10, 20, and 30 s were applied to explore the effective range of parameters to have FSSW joints with high load-carrying capacity. The joint quality of the friction stir spot-welded (FSSWed) dissimilar materials was evaluated via visual examination, tensile lap shear test, hardness test, and macro- and microstructural investigation using SEM. Moreover, EDS analysis was applied to examine the mixing at the interfaces of the dissimilar materials. Heat input calculation for the FSSW of steel–brass was found to be linearly proportional with the number of revolutions per spot joint, with maximum heat input obtained of 11 kJ at the number of revolutions of 500. The temperature measurement during FSSW showed agreement with the heat input dependence on the number of revolution. However, at the same revolutions of 500, it was found that the higher rotation speed of 1500 rpm resulted in higher temperature of 583 °C compared to 535 °C at rotation speed of 1000 rpm. This implies the significant effect for the rotation speed in the increase of temperature. The macro investigations of the friction stir spot-welded joints transverse sections showed sound joints at the different investigated parameters with significant joint ligament between the steel and brass. FSSW of steel/brass joints with a number of revolutions ranging between 250 to 500 revolutions per spot at appropriate tool speed range (1000–1500 rpm) produces joints with high load-carrying capacity from 4 kN to 7.5 kN. The hardness showed an increase in the carbon steel (lower sheet) with maximum of 248 HV and an increase of brass hardness at mixed interface between brass and steel with significant reduction in the stir zone hardness. Microstructural investigation of the joint zone showed mechanical mixing between steel and brass with the steel extruded from the lower sheet into the upper brass sheet.     

Phase II study of ifosfamide in cervical cancer

Thirty patients with symptomatic, progressive squamous cell carcinoma of the uterine cervix no longer amenable to surgery or radiotherapy were entered in a phase II study of ifosfamide (IFX). Patients were treated with IFX (5 g/m2 iv given over 24 hours) and concomitant mesna (total dose, 9.2 g/m2 iv given over 36 hours) every 21 days. One complete response (duration, 10+ months) and nine partial responses were observed, with an overall median response duration of 6.5 months. The median survival of responding patients was 11 months. Objective response rates for lesions arising in previously irradiated sites (four of 22) were significantly lower than for lesions arising in nonirradiated sites (15 of 28) (P = 0.018). There were two treatment-related deaths: one due to leukopenia-associated infection in a patient with peritonitis and severe central nervous system toxicity and one due to central nervous system toxicity without complicating factors. One other patient developed severe but reversible encephalopathy. In all remaining patients hemorrhagic cystitis and hematological and gastrointestinal toxic effects were predictable and manageable. Treatment was delayed for 1 week due to toxicity on seven of 101 occasions: four of these delays were due to mild, reversible impairment of renal function and three were due to leukopenia. Complete though reversible alopecia occurred in 22 of 30 patients. The results indicate that IFX is active in cervical cancer and deserves further study in this setting.     

Phase II Studies of Bleomycin, Ifosfamide and Cis-Platinum in Advanced and Recurrent Cervical Carcinoma

We report the results of phase II studies using a combination of ifosfamide, cis-platinum and bleomycin (BIP) in advanced and recurrent cervical cancer. Fifty-one patients have been studied. In 37 patients with disease not amenable to radical local therapy 27 objective responses (73%) were seen with 7 complete responses. Eleven of 14 patients (79%) with primary inoperable disease had at least a 50% reduction in tumour bulk prior to radical local radiotherapy. All patients experienced alopecia, nausea and vomiting. Other toxicity included myelosuppression, infection, reduction in renal function and disturbance of consciousness. There was no evidence that primary chemotherapy enhanced the acute toxic effects of pelvic radiotherapy. These data indicate that BIP is highly active in cervical cancer and can be used for effective palliation and cytoreduction in more than 70% of patients.