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Biomedical subjects

M M Negm

Publications and source records attributed to M M Negm.

7 recordsLinked to original sources
PubMed1990

Microleakage associated with retrofilling of the apical two thirds with amalgam.

In this investigation the effect of increasing the thickness of amalgam retrofilling on its sealing ability was studied and compared with the sealing ability of the laterally condensed gutta-percha with a sealer. The apical two thirds of the canals of 118 upper central incisors, filled with laterally condensed gutta-percha, were sealed with amalgam. Amalgam retrofills were also used to seal the apices of the roots of six teeth that had no other filling in their canals. The effectiveness of both techniques was determined by their ability to inhibit the penetration of methylene blue dye for the periods of 24 hours, 1 week, and 1, 3, and 6 months. At 24 hours both materials showed comparable sealing ability. However, the sealing ability of laterally condensed gutta-percha was significantly better than that of amalgam from the 1-week period until the end of the study. The depth of marginal penetration around both materials increased with time. The amount of the dye penetration increased acutely around amalgam, whereas its increase around gutta-percha was more uniform. At the end of the study, specimens retrofilled with amalgam exhibited total dye penetration that exceeded the full thickness of amalgam (6 mm) and spread into the root canal space. On the other hand, the mean value for marginal penetration of the dye around the laterally condensed gutta-percha was 2.6 mm at the end of the study. The present investigation proved beyond doubt that the use of any thickness of retrograde amalgam to seal the apex, with no other filling within the canal, invites failure.

Dental Amalgam↗
PubMed1990

The antibacterial effect of SPAD.

The antibacterial effect of SPAD, a root canal obturation paste containing paraformaldehyde, was examined and compared with that of calcium hydroxide apexification paste (Pulpdent). Both materials were either immediately placed in cultures containing streptococci group D, isolated from infected root canals, stored in an incubator for 3, 7 and 15 days before their testing, Evaluation of the antibacterial effect was carried out by measuring the diameter of bacterial inhibition zone after incubation of the materials in cultures, for 24, 48 and 27 hours. Wide inhibition zones formed around SPAD, denoting it's strong antibacterial effect, were recorded. This effect decreased with time as a result of the decrease in the amount of formaldehyde released from the hardened material into culture. On the contrary, calcium hydroxide was unable to cause inhibition of bacterial growth throughout the period of the study.

Calcium Hydroxide↗
PubMed1989

Management of endodontic pain with nonsteroidal anti-inflammatory agents: a double-blind, placebo-controlled study.

The ability of two nonsteroidal anti-inflammatory agents--piroxicam and diclofenac--to control endodontic pain was compared with that of a placebo control in a double-blind study of 267 patients requiring endodontic therapy. Endodontic treatment was carried out over three visits with an interval of 5 to 7 days between each two consecutive visits. All patients were clearly instructed to take the medication only if they experienced pain, between the visits or postoperatively, for 3 consecutive days. The patients subjectively rated their pain on a scale of 1 to 4 as none, mild, moderate, or severe. The ratings were done preoperatively and at 2, 4 and 8 hours after the initial dose of medication was taken, as well as on the second and third days. Statistical analysis of the data revealed that both piroxicam and diclofenac significantly reduced the mean pain score at the end of all observations and were significantly superior to the placebo until the end of the study. More than 90% of the patients treated with piroxicam and more than 80% of the patients treated with diclofenac showed complete relief of pain. Overall, piroxicam was clearly more effective than diclofenac or the placebo. It provided more consistent relief of pain, beginning 2 hours after the initial dose, and it continued to do so at every interval thereafter. Diclofenac required longer time to reach maximum effectiveness. Piroxicam's superiority was greater at the first and second days after the initial dose of medication was taken. With respect to side effects, piroxicam was better tolerated by the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

The effect of human blood on the sealing ability of root canal sealers: an in vitro study.

The effect of human blood and moisture contamination on the sealing ability of six commonly used root canal sealers was studied. The materials tested--Tubliseal, Diaket, AH26, Nogenol, Roth, and Endomethasone sealers--were placed in root canals with laterally condensed gutta-percha. The specimens were immediately immersed in blood or saline solution or kept dry for 2 hours. All the teeth were then subjected to methylene blue dye for 1 hour. A comparison of the seal was made by observation of dye penetration around the filling materials. Under all conditions, Tubliseal exhibited the least amount of marginal penetration, followed by AH 26. There was no significant difference in the depth of dye penetration between Diaket and Tubliseal in dry and wet conditions. Although AH 26, Nogenol, Roth, and Endomethasone sealers showed comparable sealing ability under dry conditions, the sealing ability of AH 26 and Diaket was superior to that of Nogenol, Roth, and Endomethasone sealers in moisture contamination. A significant drop in the seals afforded by AH26, Diaket, Roth, and Endomethasone sealers was recorded when these materials were immersed in blood. On the other hand, immersion in blood caused no significant change in the sealing ability of Nogenol.

Administration, Topical↗
PubMed1988

The effect of varnish and pit and fissure sealants on the sealing capacity of retrofilling techniques.

Freshly extracted teeth with single canals were instrumented and filled with laterally condensed gutta-percha and sealer. After obturation, the tooth apices were treated with various retrograde techniques. The sealing ability of these techniques, namely laterally condensed gutta-percha, heat-sealed gutta-percha, and silver amalgam retrofilling, was compared on the basis of dye penetration. The apical foramen of the treated canals was then coated with different sealing materials--HelioSeal (light-activated sealant), Delton pit and fissure sealant (chemically activated sealant), and varnish--to examine their effect on the leakage resistance of these materials. Statistical analysis indicated that laterally condensed gutta-percha, as well as retrograde amalgam filling, produced a statistically significantly better seal than heat-sealed gutta-percha. Coating of the apical foramen with different sealing materials showed that HelioSeal had significantly improved the sealing capacity of all the materials tested at each time period. Delton pit and fissure sealant did not increase the sealing ability in the first week. However, this material has significantly improved the sealing ability after the first week. On the other hand, sealing of the apical foramen with varnish did not produce any significant change in the sealing capacity of the filling materials. Finally, dye penetration around all the filling and retrofilling materials, in the presence or absence of the apical seal, continued and increased with time. However, root canals sealed with Helioseal consistently showed the least amount of apical leakage of all the canals tested.

Apicoectomy↗