Biomedical subjects

Shimon Friedman

Publications and source records attributed to Shimon Friedman.

13 recordsLinked to original sources

PubMed2007

Short-term cytotoxicity assessment of components of the epiphany resin-percha obturating system by indirect and direct contact millipore filter assays.

The Epiphany Resin-Percha Obturating System was assessed for cytotoxicity, compared with gutta-percha and AH-Plus sealer. Specimen disks (Resilon, gutta-percha), filled glass rings (sealers), or imbibed cellulose disks (primer, thinning resin) were placed over Millipore filters in direct or indirect contact with HeLa cell monolayer, incubated for 2 hours, and stained with tetrazolium blue. Cytotoxicity was rated by the surrounding unstained zone: none (0 mm), mild (</=7 mm), moderate (7-12 mm), or marked (>12 mm). Data were analyzed with one-way ANOVA and post hoc pairwise t tests. Unstained zones indicating moderate cytotoxicity were significantly larger (p < 0.05) for Epiphany primer than for thinning resin and for freshly mixed AH-Plus than for Epiphany sealer. Set sealers (24 and 48 hours), gutta-percha, and Resilon elicited noncytotoxic responses. In conclusion, cytotoxicity of set Epiphany sealer and Resilon was comparable with that of set AH-Plus and gutta-percha. Cytotoxicity of freshly mixed Epiphany sealer, primer, and thinning resin did not exceed that of freshly mixed AH-Plus.

Animals↗

PubMed2006

Treatment outcome in endodontics: the Toronto Study. Phase III: initial treatment.

The 4- to 6-year outcome of initial endodontic treatment was assessed for phase III (1998-1999) of the Toronto Study. Of the 532 teeth treated, 248 were from discontinuers (excluded), 142 from dropouts, 10 extracted, and 132 (50% recall) examined for outcome: healed (no apical periodontitis [AP], signs, symptoms) or diseased. Phase III was analyzed alone and combined with phases I, II (n = 373 teeth). Logistic regression performed on the combined phases I-III sample identified significant (p < or = 0.05) outcome predictors: preoperative AP (OR = 3.5; CI 1.7-7.2; healed: absent, 93%; present, 80%), number of roots (OR = 2.2; CI 1.0-4.7; healed: 1 - 92%; > or =2 - 83%), and intraoperative complications (OR = 2.2; CI 1.1-4.5; healed: absent, 88%; present, 76%). Treatment technique (OR = 2.8; CI 1.3-6.1; healed: Schilder, 89%; alternative, 73%) was suggested as an outcome predictor in teeth with AP, requiring confirmation from randomized controlled trials.

Adult↗

PubMed2004

Treatment outcome in endodontics-the Toronto Study. Phase II: initial treatment.

The 4- to 6-yr outcome of initial (first-time) endodontic treatment was assessed for Phase II of the "Toronto Study." In total, 442 teeth were treated by using flared preparation and vertical compaction of warm gutta-percha or step-back preparation and lateral compaction. With 126 teeth excluded (discontinuers: deceased and relocated patients), 163 dropouts, and 31 extracted, 122 (48% recall) were examined for outcome: "healed" (no apical periodontitis [AP], signs, symptoms) or "diseased" (AP, signs, or symptoms). Phase II was analyzed separately and combined with Phase I (n = 242), using Chi-square and Fisher's exact tests (p < or = 0.05). The healed rate (combined sample, 85%) differed significantly for preoperative AP (absent, 93%; present, 79%), treatment technique (flared preparation and vertical compaction, 90%; step-back preparation and lateral compaction, 80%), gender (females, 90%; males, 79%), number of roots (1-92%; > or = 2-81%), and root-filling length (adequate, 87%; inadequate, 77%). Logistic regression revealed increased risk of disease for preoperative AP (odds ratio = 3.3) and technique (odds ratio = 2.3). This study confirmed AP and highlighted treatment technique as the main predictors of outcome in initial treatment.

Adult↗

PubMed2004

Treatment outcome in endodontics: the Toronto study. Phases I and II: Orthograde retreatment.

The 4- to 6-year outcome of orthograde retreatment was assessed for Phases I and II of the Toronto Study. In total, 523 teeth in 444 patients were retreated. With 395 teeth lost to follow-up and 25 extracted, 103 teeth (34% recall) were examined by two independent, blinded, calibrated examiners for outcome: "healed" (absence of apical periodontitis, signs, or symptoms) or "diseased" (presence of apical periodontitis, signs, or symptoms). The "healed" rate (81%) differed significantly for preoperative apical periodontitis (absent, 97%; present, 78%) and perforation (absent, 89%; present, 42%). Logistic regression revealed an increased risk of disease for preoperative perforation and adequate root filling quality, and postoperative lack of definitive restoration (odds ratios = 26.5, 6.6, and 14.0, respectively). Without perforation, inadequate intraoperative root filling length was also identified (odds ratio = 6.8). This study suggested that apical periodontitis, although a strong predictor, was secondary to preoperative perforation and root filling quality, and to postoperative restoration, in predicting the outcome of retreatment.

Adult↗

PubMed2004

The benefit of the operating microscope for access cavity preparation by undergraduate students.

Although studies show the operating microscope (OM) provides benefits for endodontists, the benefit to undergraduates has not been evaluated as completely as for specialists. The purpose of this study was to determine whether using the OM would improve students' performance in endodontic access cavity preparation and canal identification. Thirty-six dental students prepared access cavities and located canals in extracted maxillary molars, before and after training, which varied according to group. The standard group received a lecture and practice in preparation of access cavities. The microscope group received identical instruction using the OM. The control group received lectures only. All groups received equal content and instruction time (2 hr 20 min). Faculty graded preparations according to a multidimensional 5-point rating scale. Using the OM, the microscope group improved significantly in access cavity preparation (p <0.05) and significantly outperformed both standard and control groups in accuracy of identifying canals (p <0.05).

Analysis of Variance↗

PubMed2004

Treatment outcome in endodontics-The Toronto Study. Phases I and II: apical surgery.

This study prospectively assessed the 4 to 8 yr outcome of apical surgery performed by graduate students in phases I and II of the Toronto Study. The study cohort included 155 teeth in 138 patients. Outcome was assessed by a blinded and calibrated examiner. Clinical and radiographic measures were used for a dichotomous outcome: healed (no signs and symptoms, Periapical Index score </= 2 or scar), or diseased (presence of signs and symptoms, or Periapical Index score >/= 3). The recall rate was 85% and the overall healed rate 74%. Healed rate was significantly higher for teeth with small (</= 5 mm) than larger preoperative lesions (chi, p = 0.02). Logistic Regression revealed an increased odds of disease persistence for teeth with larger preoperative lesions (OR = 3.81, CI = 1.2-12.1), and preoperative root-filling of adequate length (OR = 3.7, CI = 1.1-11.1). Preoperative lesion size and root-filling length were significant predictors of outcome of apical surgery.

Apicoectomy↗

PubMed2004

The success of endodontic therapy--healing and functionality.

Current, relevant knowledge on the outcome of endodontic therapy is key to clinical decision making, particularly when endodontic treatment is weighed against tooth extraction and replacement. Inherent to reviewing the outcome is a definition of "success" in relation to the goals of therapy. As the specific goal set out by the individual patient may either be healing/prevention of disease (apical periodontitis) or just functional retention of the tooth, the potential for both healing and functionality is reviewed. Based on selected follow-up studies that offer the best evidence, the chance of teeth without apical periodontitis to remain free of disease after initial treatment or orthograde retreatment is 92 percent to 98 percent. The chance of teeth with apical periodontitis to completely heal after initial treatment or retreatment is 74 percent to 86 percent, and their chance to be functional over time is 91 percent to 97 percent. Thus there does not appear to be a systematic difference in outcome between initial treatment and orthograde retreatment. The outcome of apical surgery is less consistent than that of the nonsurgical treatment. The chance of teeth with apical periodontitis to completely heal after apical surgery is 37 percent to 85 percent, with a weighted average of approximately 70 percent. However, even with the lower chance of complete healing, the chance for the teeth to be functional over time is 86 percent to 92 percent. Considering the favorable outcome, conservative endodontic therapy, both nonsurgical and surgical, is definitely justified and should be attempted when a good restorative and periodontal prognosis is projected, unless the patient is not motivated to retain the tooth.

Follow-Up Studies↗

PubMed2003

Efficacy of chlorhexidine- and calcium hydroxide-containing medicaments against Enterococcus faecalis in vitro.

OBJECTIVE: We sought to assess the efficacy of chlorhexidine (CHX) and calcium hydroxide, Ca(OH)(2), against Enterococcus faecalis in vitro. STUDY DESIGN: The effect of CHX (0.2% and 2% in gel or solution) and Ca(OH)(2) (alone or with 0.2% CHX gel) was evaluated by using the agar diffusion test and an in vitro human root inoculation method, to measure zone of inhibition or bacterial growth with optical density analysis, respectively. For optical density analysis, samples from infected root canals were collected after 7 days of medication and were cultured for 24 hours in brain-heart infusion to detect viable bacteria. RESULTS: In the agar diffusion test, CHX was effective against E faecalis in a concentration-dependent fashion, but Ca(OH)(2) alone had no effect. In the root canal inoculation test, CHX was significantly more effective against E faecalis than Ca(OH)(2) was (P < .05), but there were no significant differences between the modes of medication or concentrations of CHX. CONCLUSIONS: CHX is effective against E faecalis in vitro. Further in vivo studies are needed to confirm the value of CHX in clinical treatment.

Anti-Infective Agents, Local↗

PubMed2003

The hemolytic and cytotoxic properties of a zeolite-containing root filling material in vitro.

OBJECTIVE: This in vitro study characterized the hemolysis and cytotoxicity of ZUT, an experimental glass ionomer cement (GIC) sealer with an added antimicrobial-containing zeolite (0.2% Zeomic w/w). STUDY DESIGN: ZUT, Ketac-Cem (GIC component of ZUT), Ketac-Endo, and two AH 26 sealer formulations were tested at various times after mixing. Hemolysis produced by standardized specimens was determined spectrophotometrically (n = 6/material). Cytotoxicity was assessed by using a Millipore Filter test with a HeLa cell monolayer (n = 10/material). Tests were repeated, and results were analyzed with a one-way analysis of variance (alpha = .05). RESULTS: Disks of AH 26 containing silver produced the most hemolysis of all test groups (P < .0001). Compared to controls, GICs and AH 26 formulations were noncytotoxic at 1 and 6 hours after mixing, respectively (P > .05). Addition of Zeomic did not increase the cytotoxic and hemolytic activity of Ketac-Cem (P > .05). CONCLUSION: Overall results suggest ZUT is less cytotoxic than AH 26 and possesses characteristics similar to the other GIC formulations tested.

Analysis of Variance↗

PubMed2003

Periapical inflammation affecting coronally-inoculated dog teeth with root fillings augmented by white MTA orifice plugs.

Placement of orifice plugs has been suggested to augment the seal of conventional root canal fillings. This study assessed in vivo the efficacy of white mineral trioxide aggregate (MTA) plugs in preventing periapical inflammation subsequent to coronal inoculation of root-filled teeth. The two-rooted mandibular premolars of six beagle dogs were conventionally prepared and filled with gutta-percha and sealer. A white MTA orifice plug was placed into one canal in each tooth. Pulp chambers were inoculated with plaque except for 12 teeth (negative control), and restored. Radiographs were taken at regular intervals. At 10 months, dogs were killed and jaw blocks processed for histology. None of the roots revealed radiographic or histologic evidence of severe inflammation. Mild inflammation was observed in 17% and 39% of the roots with and without an orifice plug, respectively (McNemar, p > 0.05). Without development of severe inflammation, the seal augmentation efficacy of MTA orifice plugs could not be determined.

Aluminum Compounds↗

PubMed2003

Treatment outcome in endodontics: the Toronto Study. Phase 1: initial treatment.

This study assessed the 4- to 6-yr outcome of initial endodontic treatment during Phase 1 of the "Toronto Study" project. A total of 450 teeth were treated, alternating the "Schilder" technique and step-back with lateral condensation, and examined clinically and radiographically by an independent examiner. Apical periodontitis was recorded as absent (periapical index < 3) or present (periapical index > or = 3) and outcome dichotomized as "healed" (no apical periodontitis, no signs or symptoms) or "disease." Univariate, bivariate, and multivariate analyses were performed (p = 0.05) on 120 examined teeth. The "healed" rate (81% overall) was significantly higher for teeth treated without apical periodontitis (92%) than with apical periodontitis (74%). Several other factors were associated with healing rate differential of 10% or higher, but no statistical significance. This study confirmed apical periodontitis as the main prognostic factor in initial endodontic treatment. Continuation of the project will allow assessment of other prognostic factors with better power.

Chi-Square Distribution↗

PubMed2002

Substantive antimicrobial activity in chlorhexidine-treated human root dentin.

OBJECTIVE: The aim of this in vitro study was to assess the substantive antimicrobial activity of different medicaments in human root dentin. STUDY DESIGN: Canals of 98 roots were enlarged to standard size and medicated for 7 days with the following: (1) 2% chlorhexidine (CHX) gel, (2) 0.2% CHX gel, (3) 2% CHX solution, (4) Ca(OH)(2), (5) Ca(OH)(2)+ 0.2% CHX gel, (6) 2% CHX solution + a 25% CHX-containing controlled-release device, (7) saline, and (8) gel vehicle. After medication, canals were inoculated with Enterococcus faecalis for 21 days. Dentin samples were collected with Gates-Glidden burs into brain heart infusion broth, and bacterial growth was assessed with spectrophotometric analysis of optical density after 72 hours of incubation. RESULTS: Mean optical densities were significantly lower for groups with 2% CHX (1, 3, and 6) when compared with those of the controls (P < .05, analysis of variance with the Tukey test). Other groups did not differ significantly from the controls. CONCLUSIONS: Canal dressing for 1 week with 2% CHX may provide residual antimicrobial activity against E faecalis.

Analysis of Variance↗

PubMed2002

Quality of life and satisfaction outcomes of endodontic treatment.

The purpose of this study was to assess quality of life and satisfaction in relation to endodontic treatment in two Canadian populations and the association of these outcomes with the treatment providers' level of training (generalist or endodontist). New patients aged 25 to 40, presenting at the dental faculties in Toronto and Saskatoon were screened. Patients with radiographically identifiable endodontic treatment were invited for interviews conducted using a questionnaire that measured changes in quality of life after endodontic treatment and semantic differential scales that measured satisfaction with endodontic treatment. Data were analyzed using Chi-square, multiple and logistic regression (p < 0.05), and Mann-Whitney U test (p < 0.02). Subjects reported preoperative factors (e.g., pain, sleep disturbances) impacting quality of life, which improved after endodontic treatment, significantly more in the Toronto than in the Saskatoon population. Satisfaction was significantly better when endodontic treatment was provided by endodontists.

Adult↗