Biomedical subjects

Ashraf F Fouad

Publications and source records attributed to Ashraf F Fouad.

10 recordsLinked to original sources

PubMed2026

Comprehensive Microbiome Analyses for Regenerative Endodontic Therapy.

INTRODUCTION: Comprehensive microbiome analyses include the study of all microbial taxa, including bacteria, archaea, viruses, and fungi, as well as their functional activities and antibiotic resistance gene expression. Regenerative endodontic therapy presents a clinical situation where the most effective antimicrobial approaches are needed in order to ensure clinical success. METHODS AND RESULTS: In this paper, different contemporary technologies for the identification of endodontic microorganisms, such as with next generation sequencing, and their functional characterization, such as with whole genome sequencing, are described. The role of transcriptomics, as well as resistome analysis, are also discussed. Furthermore, the manner in which all this work and knowledge could be incorporated into clinical endodontics in general, and regenerative endodontic therapy as a special treatment, is outlined. CONCLUSIONS: Comprehensive microbiome analysis can lead to the development of more effective and personalized antimicrobial treatment.

Endodontics↗

PubMed2005

Effectiveness of a calcium hydroxide and chlorhexidine digluconate mixture as disinfectant during retreatment of failed endodontic cases.

OBJECTIVE: The purpose of this in vivo investigation is to compare the effect of a slurry of Ca(OH)2 mixed in aqueous 2% chlorhexidine (CHX) versus aqueous Ca(OH)2 slurry alone on the disinfection of the pulp space of failed root-filled teeth during endodontic retreatment. STUDY DESIGN: Forty single-rooted previously root-filled teeth with associated periradicular lesions were included. The teeth were nonsurgically retreated and medicated over 3 treatment visits with 7-10-day intervals with either Ca(OH)2 in water or Ca(OH)2 in 2% aqueous CHX. Root canal cultures were collected in fluid thioglycollate, and bacterial growth was assessed by turbidity daily for 1 week, then weekly for an additional 3 weeks. The presence of enterococci in the root canals at the initial treatment session was determined. RESULTS: Of the total sample population, 12 of 40 (30%) were positive for bacteria before root filling. The control medication disinfected 12 of 20 (60%) teeth including 2 of 4 teeth originally diagnosed with enterococci. The experimental medication resulted in disinfected 16 of 20 (80%) teeth at the beginning of the third appointment. None of the teeth originally containing enterococci showed remaining growth. This difference between the overall positive cultures was not statistically significant (P > .05). CONCLUSIONS: Canal dressing with a mixture of 2% CHX and Ca(OH)2 slurry is as efficacious as aqueous Ca(OH)2 on the disinfection of failed root-filled teeth.

Adult↗

PubMed2005

Molecular detection of Enterococcus species in root canals of therapy-resistant endodontic infections.

OBJECTIVES: The objectives were to identify Enterococcus spp in nonhealing endodontic cases using PCR amplification and molecular sequencing, and to determine if the prevalence of enterococci is increased in diabetic patients. STUDY DESIGN: Specimens from 40 cases undergoing retreatment were incubated in prereduced thioglycollate broth at 37 degrees C. Extracted DNA had PCR amplification using primers that target the tuf gene of 14 Enterococcus spp. PCR products were directly sequenced and identified phylogenetically. RESULTS: Three cases were eliminated because the patients were on antibiotics or the tooth did not have a periradicular radiolucency. The remaining 37 specimens included 6 from diabetic patients. Eight specimens were positive for Enterococcus spp. Of these, 6 (19%) were from nondiabetic and 2 (33%) from diabetic patients (odds ratio = 2.1; chi squared, P = .45). Phylogenetically, all sequences from positive specimens matched E faecalis V583 (AE016947). Conclusion E faecalis was the only enterococcal species detected, with an overall prevalence of 22%.

Adult↗

PubMed2005

Apical anatomy in mesial and mesiobuccal roots of permanent first molars.

The purpose of this in vitro study was to investigate the canal configuration types, and the prevalence and location of anatomical variations in the mesiobuccal (MB) and mesial roots of permanent maxillary and mandibular first molars after instrumentation. The number and the type of canals were determined before instrumentation using conventional methods. All root canals from the 47 MB roots and 42 mesial roots were then instrumented to size #30 with ProFile .04 taper rotary instruments in a crown-down method and then filled with a single gutta-percha cone and sealer. Transverse 1 mm-thick cross-sections at 2, 3, 4, and 5 mm from the apex were obtained, stained and examined using a stereomicroscope. The canal configuration types and the prevalence and location of isthmi and accessory canals in roots with two canals were evaluated. The prevalence of two canals was 80.8% in the maxillary MB roots and 95.2% in the mandibular mesial roots. There were six types of canal configurations in the instrumented root apices. The prevalence of anatomical variations was highest at the apical 4 mm level, and was more frequent in mandibular first molars, and in roots with Weine type III canal. chi test showed that the prevalence of the anatomical variations was statistically higher in the maxillary MB roots with Weine type III canals than in those with Weine type II canals (p < 0.05). Different canal configurations were often found at different levels in the same root. The results indicate that anatomical variations persist following instrumentation of roots with two canals in first molars. These anatomical variations should be considered during surgical or nonsurgical endodontic procedures of the permanent first molars.

Chi-Square Distribution↗

PubMed2005

The effect of antibiotics and endodontic antimicrobials on the polymerase chain reaction.

The effectiveness of endodontic antimicrobial treatment could be determined using sensitive molecular methods. The purpose of this study was to determine if antibiotics or endodontic reagents interfere with the ability of PCR to detect Enterococcus faecalis in vitro. Amoxicillin (25 mg/ml), clindamycin (15 mg/ml), tetracycline (25 mg/ml), doxycycline (10 mg/ml), calcium hydroxide, 1% buffered sodium hypochlorite (NaOCl1), 3% and 6% unbuffered NaOCl (NaOCl3 and NaOCl6), 2% chlorhexidine (CHX), 5% tincture iodine (TI), 2% iodine potassium iodide (IKI), chloroform (CF), 70% ethyl alcohol, 5% sodium thiosulphate, 5% citric acid or saline were added to 10 or 10 cells/ml E. faecalis ATCC 19433 for 1 h (1 wk for Ca(OH)2). Using PCR, all specimens were positive except for NaOCl3 and NaOCl6. PCR with Ca(OH)2 was positive with 10 cells/ml but negative with 10 cells/ml. The following reagents yielded negative culturing results: all antibiotics, Ca(OH)2, CHX, IKI, TI, NaOCl3, NaOCl6, and CF. BacLight nuclear staining revealed the presence of viable cells in all PCR positive, culture negative combinations, except for those with CF. Therefore, in the presence of threshold values of bacterial concentrations, all reagents tested except for NaOCl3 and NaOCl6 do not interfere with the detection of E. faecalis using PCR.

Animals↗

PubMed2005

Enterococcus spp. in endodontically treated teeth with and without periradicular lesions.

The purpose of this study was to determine if Enterococcus spp. are more prevalent in endodontically treated teeth with periradicular lesions compared with teeth that require retreatment but have no periradicular rarefaction. Fifty-eight teeth that had received root canal therapy more than 1 yr previously and required retreatment were included. Designation of lesion versus no lesion was determined by two experienced endodontists. DNA extraction and PCR amplification were performed using ubiquitous 16S rDNA bacterial primers, as well as Enterococcus spp.-specific primers. The results showed that the overall prevalence of bacteria was 90% and Enterococcus spp. was 12%. chi analysis revealed a statistically significant relationship between the presence of a lesion and the presence of bacteria, as detected by the universal primers (p = 0.032). Using logistic regression, a statistically significant relationship was found between teeth with normal periapex and the presence of Enterococcus spp. (p = 0.023). This study revealed that bacteria are significantly associated with endodontic treatment failure but enterococci are not associated with disease.

Adult↗

PubMed2004

Effects of removing residual peroxide and other oxygen radicals on the shear bond strength and failure modes at resin-tooth interface after tooth bleaching.

PURPOSE: To investigate the effects of removing residual peroxide on the bond strength and the failure mode at the interface of resin-based composite and enamel after tooth bleaching. METHODS: Standard-sized light-cured resin cylinders were formed on, and bonded to the flattened bleached enamel surfaces of 60 human canine and premolars which had previously been subjected to three different surface treatments for 3 minutes: (1) catalase; (2) 70% ethanol; (3) sprayed water. For each experimental group (n=12), non-bleached teeth and 2-week post-bleached teeth without any surface treatment were used for negative and positive control respectively. Specimens were thermocycled, tested in shear until failure, and the results statistically analyzed. All fractured specimens were examined by scanning electron microscopy. RESULTS: Pretreatment of bleached surface with the catalase and the ethanol prior to bonding significantly improved the composite-enamel bond strength compared to the water-sprayed group (P< 0.05). However, the bond strength level of the ethanol group did not return to the level recorded for the non-bleached negative control group. Scanning electron microscopic examination of randomly selected, fractured specimens indicated that the peroxide-induced reduction in bond strength was related to alterations in both attachment-surface area at the resin-enamel interface and resin quality.

Analysis of Variance↗

PubMed2003

The effect of diabetes mellitus on endodontic treatment outcome: data from an electronic patient record.

BACKGROUND: The authors used a custom-built electronic record system to investigate endodontic diagnostic and treatment outcome data in patients with and without diabetes. METHODS: The medical histories and endodontic treatment data for nonsurgical endodontic patients treated in predoctoral and postgraduate specialty clinics were entered into an electronic record system. A total of 5,494 cases (including 284 cases in patients with diabetes) were treated, and 540 cases (including 73 cases in patients with diabetes) had follow-up data two years or more postoperatively. The authors performed univariate and multivariate analyses to determine important factors affecting endodontic diagnosis and treatment outcome. RESULTS: Patients with diabetes had increased periodontal disease of teeth with endodontic involvment compared with patients who did not have diabetes. There was a trend toward increased symptomatic periradicular disease in patients with diabetes who received insulin, as well as flareups in all patients with diabetes. Two years or longer postoperatively, 68 percent of cases followed were successful. Older age, the absence of preoperative lesions, the presence of permanent restorations and longer postoperative evaluation periods all were associated with a successful outcome. A multivariate analysis showed that in cases with preoperative periradicular lesions, a history of diabetes was associated with a significantly reduced successful outcome. CONCLUSIONS: Patients with diabetes have increased periodontal disease in teeth involved endodontically and have a reduced likelihood of success of endodontic treatment in cases with preoperative periradicular lesions. CLINICAL IMPLICATIONS: Patients with diabetes who are treated endodontically should be assessed carefully and be treated with effective antimicrobial root canal regimens, particularly in cases with preoperative lesions.

Acute Disease↗

PubMed2003

Diabetes mellitus as a modulating factor of endodontic infections.

Diabetes mellitus is a chronic disease with serious health consequences. The association between diabetes and periodontal disease is well documented. However, the progression and healing of endodontic infections in diabetic patients has not been adequately studied. In this review, diabetes mellitus is explored as a potential modulating factor of endodontic pathosis. Recent data on the relationship between the clinical presentation of pulpal and periradicular disease, as well as the outcome of endodontic treatment in diabetic and nondiabetic patients, are presented. Diabetics who present for endodontic treatment, particularly those with periradicular pathosis, may have increased perioperative symptoms. Cases with preoperative periradicular lesions are less likely to be determined successful two years or longer postoperatively if the patient reports a history of diabetes. Studies examining the pathogenesis of periradicular lesions in mouse models with uncontrolled type 1 diabetes suggest that the lesion size may be increased and the animals have increased serious sequelae. Preliminary findings suggest that some bacterial species may be more prevalent in necrotic pulp of diabetic than nondiabetic patients. More studies are needed to further explore the microbiology of endodontic infections and to determine effective treatment strategies in both diabetic and nondiabetic patients.

Animals↗

PubMed2002

PCR-based identification of bacteria associated with endodontic infections.

PCR primers that target the bacterial 16S rRNA genes (or the tuf gene for the genus Enterococcus) were used to identify 10 putative bacterial pathogens in root canals with necrotic pulp. In addition, the associations of these microorganisms with symptoms and a history of diabetes mellitus were investigated. Microbial samples from the root canals of 24 teeth with necrotic pulp were included in the study. PCR with universal bacterial primers identified bacterial DNA in 22 specimens; the remaining 2 specimens were from intact teeth that had been traumatized 6 months prior to treatment. PCR with specific primers showed that preoperative symptoms were significantly associated with the presence of Streptococcus spp. (P < 0.001 by chi-square analysis). There was also a nonsignificant trend for symptoms to be associated with Fusobacterium nucleatum and Porphyromonas gingivalis (odds ratio, >2) and for diabetes mellitus to be associated with P. gingivalis and Porphyromonas endodontalis (odds ratio, >2). Cloning and sequencing of the universal PCR product in one specimen revealed the presence of an organism related to the genus Olsenella, which has not previously been described in endodontic infections.

Bacteria↗