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Biomedical subjects

A F Fouad

Publications and source records attributed to A F Fouad.

14 recordsLinked to original sources
PubMed2003

Molecular characterization of the presence of Eubacterium spp and Streptococcus spp in endodontic infections.

Eubacterium spp. and Streptococcus spp. are virulent, commonly identified microorganisms in endodontic infections. The purpose of this study was to use molecular methods to identify these organisms in 22 infected root canals that include eight cases with preoperative clinical symptoms and five cases with a history of diabetes mellitus. The presence of Streptococcus spp. and Eubacterium spp. was examined using two sets of PCR primers specific with multiple species within the respective genera. Positive specimens had their PCR products sequenced and phylogenetically analyzed to identify the specific species. Sixteen specimens (73%) contained Eubacterium spp. and nine (41%) were positive for Streptococcus spp. Eubacterium infirmum was the most prevalent Eubacterium sp. This organism was significantly associated with a history of diabetes (OR = 9.6; P = 0.04). Streptococcus anginosus was the most common Streptococcus sp., but neither it nor any of the other streptococci were significantly associated with the clinical parameters evaluated.

Bacterial Typing Techniques↗
PubMed2001

Periapical lesion progression and cytokine expression in an LPS hyporesponsive model.

AIM: The purpose of this study was to compare periapical lesion progression and the expression of the bone modulating cytokines IL-1alpha, TNF-alpha, IL-4, IL-6 and IL-11 in periapical lesions of normal and C3H/HeJ (LPS hyporesponsive) mice. METHODOLOGY: Pulps of both mandibular first molars from C3H/HeJ and BALB/c (normal) mice were exposed and inoculated with normal mouse oral microorganisms for 2, 4, 6, and 8 weeks. After euthanasia, specimens were prepared for histological examination. A quantitative evaluation of the lesional area and immunohistochemical stain counts was performed. RESULTS: There were no statistically significant differences in progression of periapical lesions for both mouse strains with time (two-factor ANOVA, P > 0.05). The immunohistochemical staining revealed no overall differences between the two strains in levels of expression of the cytokines (P > 0.05). IL-11 expression did not change from control levels in BALB/c mice, but correlated with the expression of IL-6 and IL-4 in C3H/HeJ mice. CONCLUSION: Responsiveness to LPS may not be significant in the pathogenesis of periapical lesions and in cytokine expression within the lesions, when the lesions are induced by non-specific oral flora.

Analysis of Variance↗
PubMed2001

Effects of enamel matrix derivative on gene expression of primary osteoblasts.

OBJECTIVE: The aim of this study was to investigate the effects of enamel matrix derivative (EMD) on gene expression of collagen alpha1 (I), osteocalcin, prostaglandin G/H synthase 2 (PGHS-2), interleukin-6, and insulin-like growth factor I in primary mouse osteoblasts. STUDY DESIGN: Primary osteoblasts were digested from 6- to 8-day-old mouse calvaria. Cells were divided into 4 groups and cultured for 24, 48, and 72 hours with a serum-free modified Eagle medium as negative control, modified Eagle medium with 25 microg/mL EMD, modified Eagle medium with 100 microg/mL EMD, and modified Eagle medium plus 10% fetal bovine serum as positive control. Gene expression was determined by Northern blot and reverse transcription polymerase chain reaction analysis. RESULT: EMD enhanced collagen I, interleukin-6, and PGHS-2 expression and did not stimulate the expression of osteocalcin and IGF-I. CONCLUSION: These results indicate that EMD might regulate certain gene expression during periodontal tissue regeneration.

Animals↗
PubMed2000

Effect of using electronic apex locators on selected endodontic treatment parameters.

The purpose of this study was to determine the effect of using electronic apex locators on the number of radiographs taken and the adequacy in length of the final obturation. Patients in an undergraduate student endodontics clinic participated in the study. The working length (WL) was estimated by the authors for all cases (36 teeth; 58 canals), using both a preoperative standardized radiograph and an electronic measurement. The students were then asked to place WL files to one of the estimates (electronic or radiographic; chosen by random assignment) and take a WL radiograph. Neither the students nor their instructors knew which method was chosen for the estimates. Once treatment was completed, the total number of working radiographs was counted. The number of cases with acceptable (0 to 2 mm short of the apex) or unacceptable obturation was also blindly registered. An electronic estimate of the WL improved length quality of the final obturation, compared with a radiographic estimate. The number of working radiographs taken was less in the electronic apex locator group in anterior and premolar teeth, but not in molars.

Adult↗
PubMed1997

IL-1 alpha and TNF-alpha expression in early periapical lesions of normal and immunodeficient mice.

T-helper and B-lymphocytes may contribute to mechanisms that result in bone-resorptive cytokine production in periapical lesion. Mice with severe combined immunodeficiency (scid) lack functional B- and T-cell immunity. The purpose of this study was to investigate the progression of pulp necrosis and the histomorphometric features of periapical lesions in scid vs. normal mice. The expression of the bone-resorptive cytokines IL-1 alpha and TNF-alpha was also investigated. Sixteen five-week-old homozygous scid mice and 14 normal BALB/cJ mice were used. The pulps of mandibular first molars were exposed for 1, 2, 3, or 4 weeks. Blocks of tissue containing the mandibular teeth and supporting structures were processed for both light microscopic examination and immunohistochemical staining for IL-1 alpha dna TNF-alpha. Central sections were randomized, their images were blindly digitized into a computer, and the areas of the lesions surrounding the distal root apices were measured. The cells that stained positively for the cytokines in the same area of adjacent sections were counted. Pulp necrosis progressed at similar rates in teeth from both strains. A progressive and significant increase in the periapical lesion size in both strains was observed. The scid mice lesions were significantly smaller than the controls at only the three-week period. There was heavy cytokine staining in periapical lesions from both strains, especially in areas that contained a mixed inflammatory infiltrate or fibroblasts. The number of positively staining cells was proportional to the lesion size. Therefore, pulpal and periapical pathosis were independent of the presence of functional T- and B-cells in this model.

Alveolar Bone Loss↗
PubMed1997

Effectiveness of an endodontic diagnosis computer simulation program.

The effectiveness of a recently developed endodontic diagnosis computer simulation program was examined. Third-year dental students (n = 90) in three successive academic classes were given a pre-test in endodontic diagnosis before any endodontic instruction, and then received ten lectures on diagnostic techniques, endodontic pathology, and radiographic interpretation. The students were subsequently divided into three equal groups not differing statistically on their pre-test results. The first group used an endodontic computer simulation program containing fifteen patient simulations for one hour. The second group had a small-group seminar aiming to cover the same material as in the computer program in the same time period. The third group (control) had no further instruction. The three groups then took a post-test to evaluate their diagnostic knowledge in endodontics. The improvement of scores from pre- to post-test in the three groups were statistically different (p = 0.018). The simulation group students improved significantly more than the seminar group (p = 0.05) and the Control Group (p = 0.0024). Difference in improvement between the seminar group and the control group was not statistically significant (p = 0.20). Students were able to cover more cases on average using the simulation program than were covered in the seminar (t-test, p < 0.0001).

Computer Simulation↗
PubMed1996

Penicillin as a supplement in resolving the localized acute apical abscess.

PROBLEM: Antibiotics are often prescribed indiscriminately to treat endodontic emergencies. OBJECTIVES: This study examined (1) the effect of penicillin supplementation on reduction of symptoms and (2) the course of recovery of localized acute apical abscess after emergency treatment. STUDY DESIGN: Patients with pulp necrosis and periapical pain and/or localized swelling were considered. Those eligible did not have any signs of spreading infections. Patients received appropriate local treatment, and a double-blind protocol was used to randomly assign them to one of three groups: penicillin VK group, placebo group, or neither medication group. All received ibuprofen 600 mg four times daily for 24 hours. Patients entered their pre- and postoperative pain and swelling experience on a visual analog scale for up to 72 hours. RESULTS: Resolution was fairly rapid in most patients. Statistical analysis of the scores of 32 respondents revealed no significant differences (at p < 0.05) between the three groups in course of recovery or symptoms at any time period. CONCLUSIONS: Patients with localized periapical pain or swelling generally recovered quickly with local treatment. The data did not show a demonstrable benefit from penicillin supplementation.

Acute Disease↗
PubMed1993

Healing of induced periapical lesions in ferret canines.

A previous study showed that the ferret canine is an appropriate model for inducing periapical lesions. Ferret canines were used in this study to study changes in periapical lesions after root canal treatment (RCT). After periapical pathosis was induced in the maxillary and mandibular canines of six ferrets, RCT was performed on three of the four canines in each animal. Each ferret received periodic intraperitoneal injections of Procion red dye. Two animals were killed at each of 4, 8, and 12 wk after RCT. Apices and surrounding lesions were evaluated radiographically, histologically, and by fluorescent microscopy. Periapical radiolucencies increased in size during induction but showed no changes after RCT. Lesions in untreated teeth showed features of granulomatous inflammation, mainly the presence of macrophages and lymphocytes. After RCT, there was histological evidence of healing in the form of cementum deposition, increased vascularity, and increased fibroblastic and osteoblastic activity. Fluorescent staining showed cementum deposition of variable thickness in the treated specimens.

Animals↗
PubMed1993

Accuracy of the Endex with variations in canal irrigants and foramen size.

Several electronic apex locators (EALs) are currently available. The manufacturer of a new device, the Endex, claims that it is accurate regardless of canal conditions. This study compared the accuracy of the Endex with that of the Exact-a-pex, the Sono-Explorer Mark III, and the Neosono-D SE as to the effects of fluids in the canal and variation in foramen size. Sixty extracted single-canaled teeth were divided into two groups (narrow and wide foramina), depending on whether the apical foramina permitted the tip of a #30 K file to pass through. An in vitro model was used, in which teeth were fitted in test tubes with the roots immersed in 1% agar in phosphate-buffered saline. Root canal lengths were measured in dry canals, then with ethanol, Xylocaine, and sodium hypochlorite in the canals by each electronic apex locator. These lengths were compared with those of the actual root canal lengths. No significant differences were noted among the instruments in dry canals regardless of the foramen size. The endex was generally superior to the other instruments examined in canals containing conductive fluids, especially where the apical foramen was widened.

Chi-Square Distribution↗
PubMed1992

Induced periapical lesions in ferret canines: histologic and radiographic evaluation.

Ferrets have been utilized in endodontic research to study periapical responses. However, various aspects of induction and healing of periapical pathosis in ferrets are unclear. This study evaluated the radiographic and histopathologic features of induced periapical lesions. Periapical pathosis was consistently produced in 8 canines of 2 ferrets by extirpating the pulp, leaving the cavities open for a week, then sealing for 12 weeks. The resulting lesions were evaluated radiographically every two weeks. The animals were then killed and the induced lesions evaluated histologically and histobacteriologically. Four untreated canines from 2 other ferrets were used as controls. Results showed that periapical rarefactions were visible in all teeth in the experimental group within 4 weeks. Histologically, the induced lesions consisted principally of a mononuclear inflammatory infiltrate, dominated by macrophages but with numerous lymphocytes. With Brown & Brenn staining, bacteria were demonstrated in the pulp space of teeth in which the lesions were induced and in the apical arborization of the canal system. Only one specimen had bacteria within the periapical lesion.

Animals↗
PubMed1990

Clinical evaluation of five electronic root canal length measuring instruments.

A previous in vitro study has shown high accuracy, but no clinically significant differences in a group of five electronic root canal length measuring instruments. The purpose of this study was to evaluate and compare the performance of the same group of instruments under clinical conditions and to correlate their accuracy to radiographic estimates of canal length. Five electronic root canal length measuring instruments were used to measure the working length to the "apex" in 20 single-rooted teeth scheduled for extraction. After extraction, the actual canal length was measured visually to a point just within the apical foramen. This length was compared with instrument length as determined electronically. The accuracy of the instruments in determining canal measurement within +/- 0.5 mm from the apical foramen varied from 55 to 75%. The differences between the instruments were not statistically significant. On average, all of the instruments except for the Endocater gave canal length measurements that were beyond the apical foramen. The variability of the measurements, which was comparable to that of estimates of canal length from preoperative radiographs, indicated that radiographic verification of the working length is still desirable.

Adult↗
PubMed1989

An in vitro comparison of five root canal length measuring instruments.

Several new root canal length measuring instruments (RCLMI) have recently been introduced claiming superiority over older systems. The purpose of this study was to compare five models of these instruments with respect to their accuracy under a given set of specified conditions. The five RCLMI tested were: the, Exact-a-pex, the Endocater, the Neosono-D, the Apex Finder, and the Sono-Explorer, Mark III. The conditions tested were the accuracy of the instruments in determining the working length, the consistency of measurement following canal instrumentation and with conductive gutta-percha points in place, and the operation of the RCLMI in the presence of fluids frequently found in root canals during endodontic treatment. An in vitro model was used to test these instruments. A set of 20 teeth was tested using the conditions specified above. All data were compared using the mean difference from the actual canal length of the teeth. The results indicated that there were no significant differences among measurements derived from the five instruments, under the specified conditions. There was a slight variation of the measurements by all instruments when they were used following instrumentation and with the use of conductive gutta-percha points. When fluids were present in the canals, the reliability of the RCLMI depended on the electrical conductivity of the fluid tested. The poorest results were obtained when either sodium hypochlorite or blood were present in the canals.

Dental Instruments↗