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PubMed2004

An in vitro study evaluating the effect of ferrule length on fracture resistance of endodontically treated teeth restored with fiber-reinforced and zirconia dowel systems.

STATEMENT OF PROBLEM: There are few published studies analyzing the effects of different ferrule lengths of endodontically treated teeth in relationship to newly developed fiber-reinforced and zirconia dowel systems. PURPOSE: This in vitro study compared the effect of 3 different ferrule lengths on the fracture resistance and fracture patterns of crowned endodontically treated teeth restored with 4 different esthetic dowel systems. MATERIAL AND METHODS: The crowns of 123 human maxillary canines were removed at the cementoenamel junction and the roots were endodontically treated. Three master tooth models were prepared to ferrule lengths of 1.0 mm, 1.5 mm, and 2.0 mm to produce 3 master analogs. Each root was embedded in autopolymerizing resin with a 0.2-mm layer of silicone impression material to simulate the periodontal ligament. Forty analogs of each master tooth, with ferrule lengths of 1.0 mm, 1.5 mm, and 2.0 mm were produced with copy-milling (Celay system). Each group was further subdivided into 4 groups of 10 specimens each and restored with 4 different esthetic dowel systems (quartz fiber, glass fiber, glass fiber plus zirconia, and zirconia). All dowels were luted with adhesive resin cement (RelyX ARC), restored with composite cores (Valux Plus), and Ni-Cr alloy (Wiron 99) complete crowns. All specimens were loaded at 130 degrees to the long axes in a universal testing machine at a crosshead speed of 1 mm/min until fracture. Fracture patterns were classified as failures above or below the incisal third of the roots. The data were analyzed with 2-way ANOVA and Tukey HSD tests (alpha=.05). A Fisher exact test was conducted for evaluation of the mode of failure (alpha=.05). RESULTS: Mean failure loads (kg) for quartz fiber, glass fiber, glass fiber plus zirconia, and zirconia groups, respectively, with the 3 ferrule lengths were: 1.0-mm ferrule specimens: 98.09 +/- 2.90, 85.36 +/- 2.82, 80.24 +/- 1.88, 70.11 +/- 2.48; 1.5-mm ferrule specimens: 101.0 +/- 2.88, 87.58 +/- 2.83, 89.8 +/- 2.09, 82.71 +/- 2.14; 2.0-mm ferrule specimens: 119.5+/-1.78, 99.84+/-1.23, 98.6 +/- 1.64, 95.42 +/- 1.02. Teeth prepared with 2.0-mm ferrules demonstrated significantly higher fracture thresholds (P<.001). There were no significant differences in fracture patterns. CONCLUSION: Increasing the ferrule length of the endodontically treated teeth from 1 mm to 1.5 mm in specimens restored with quartz-fiber and glass-fiber dowels did not produce significant increases in the failure loads (P=.084, P=.119, respectively). No significant difference was detected between glass-fiber and glass-fiber plus zirconia dowels with 1.5-mm and 2.0-mm ferrules (P=.218, P=.244, respectively). However, fracture thresholds were higher for all 4 dowel systems when the specimens were prepared with a 2.0-mm ferrule length (P<.001).

Analysis of Variance↗
PubMed2005

Fracture resistance of endodontically treated maxillary premolars restored with CAD/CAM ceramic inlays.

STATEMENT OF PROBLEM: Endodontically treated posterior teeth are more likely to fracture compared to posterior teeth with vital pulps. Reinforcement with an extracoronal restoration that covers the cusps is the most commonly recommended method for reducing the risk of fracture. It is not known whether bonded intracoronal restorations without cuspal coverage will reduce the risk of fracture. PURPOSE: The aim of this in vitro study was to investigate whether reinforcement of endodontically treated premolars with MOD preparations could be achieved by insertion of bonded CAD/CAM ceramic inlays. MATERIAL AND METHODS: Forty-five extracted maxillary premolars were equally distributed among 3 groups (END, CER, CTR). In group END (n=15), root canals were enlarged with a rotary NiTi system and obturated with heat-softened gutta-percha around a plastic carrier (Thermafil). After filling of the endodontic access cavities with autopolymerizing composite resin (Luxacore), standardized MOD cavity preparations were made and CAD/CAM ceramic inlays (CEREC) were fabricated and then bonded to the teeth with composite resin (Tetric) and an adhesive system (Syntac Classic). In group CER (n=15), teeth without endodontic treatment were restored with bonded inlays (CEREC). Sound premolars served as controls (group CTR, n=15). Teeth were then thermal cycled (1445 cycles, dwell time: 30 seconds, 5 degrees /55 degrees C). An eccentric load was applied on the buccal incline of the palatal cusp in a universal testing machine until cusp fracture (N). Fracture load was evaluated with the Mann-Whitney test, and type of fracture, with a chi-square analysis (alpha=.05). The type of fracture was determined by visual inspection: type I - supragingival fracture within the palatal cusp; type II - fracture below cemento-enamel junction of palatal cusp; and type III - fracture of palatal cusp and central portion of the tooth exposing the root canal cavity. RESULTS: No significant difference was found among the 3 groups with respect to load required for fracture. Mean fracture load +/- SD was recorded as follows: 291.6 +/- 113.7 N for group END, 363.2 +/- 140.3 N for group CER, and 296.5 +/- 170.5 N for group CTR. Regarding fracture modes, significantly more teeth from group END exhibited fractures of type III and II compared with control specimens. CONCLUSION: Teeth restored with bonded CAD/CAM ceramic inlays (CEREC) fractured with a significantly higher number of severe fractures compared to the control group.

Bicuspid↗
PubMed2006

Effect of a crown ferrule on the fracture resistance of endodontically treated teeth restored with prefabricated posts.

STATEMENT OF PROBLEM: Root fracture is one of the most serious complications following restoration of endodontically treated teeth. PURPOSE: The purpose of this study was to compare the fracture strengths of endodontically treated teeth using posts and cores and variable quantities of coronal dentin located apical to core foundations with corresponding ferrule designs incorporated into cast restorations. MATERIAL AND METHODS: Fifty freshly extracted canines were endodontically treated. The teeth were randomly divided into groups of 10 and prepared according to 5 experimental protocols. CONTROL GROUP: teeth with custom cast post and core; 0-mm group: teeth without coronal structure (no ferrule); 1-mm, 2-mm, and 3-mm groups: teeth with 1 mm, 2 mm, and 3 mm of remaining coronal tooth structure (1-, 2-, and 3-mm ferrule), respectively. All specimens in 0-mm through 3-mm (noncontrol) groups were restored with a prefabricated post (Screw-Post) and composite resin (Z100) core located superior to the different tooth structure heights. All teeth were restored with complete metal crowns. The fracture resistance (N) was measured in a universal testing machine at 45 degrees to the long axis of the tooth until failure. Data were analyzed by 1-way analysis of variance and Tukey test (alpha=.05). RESULTS: Significant differences (P<.001) were found among the mean fracture forces of the test groups (control group: 818.2 N; 0-mm, 1-mm, 2-mm, and 3-mm groups: 561.0 N, 627.6 N, 745.3 N, and 907.1 N, respectively). When the mode of failure was evaluated, all failures in the control group occurred due to root fracture, and all failures in the 0-mm group occurred due to core fracture. The majority of failures in the other groups occurred due to crown cementation failure. CONCLUSION: The results of this study showed that an increased amount of coronal dentin significantly increases the fracture resistance of endodontically treated teeth.

Analysis of Variance↗
PubMed2006

Resistance to fracture of two all-ceramic crown materials following endodontic access.

STATEMENT OF PROBLEM: There is currently no protocol for managing endodontic access openings for all-ceramic crowns. A direct restorative material is generally used to repair the access opening, rendering a repaired crown as the definitive restoration. This endodontic procedure, however, may weaken the restoration or initiate microcracks that may propagate, resulting in premature failure of the restoration. PURPOSE: The purpose of this in vitro study was to evaluate how an endodontic access opening prepared through an all-ceramic crown altered the structural integrity of the ceramic, and the effect of a repair of this access on the load to failure of an all-ceramic crown. MATERIAL AND METHODS: Twenty-four alumina (Procera) and 24 zirconia (Procera) crowns were fabricated and cemented (Rely X Luting Plus Cement) onto duplicate epoxy resin dies. Twelve crowns of each were accessed to simulate root canal treatment therapy. Surface defects of all accessed specimens were evaluated with an environmental scanning electron microscope. The specimens were repaired with a porcelain repair system (standard adhesive resin/composite resin protocol) and were loaded to failure in a universal testing machine. Observations made visually and microscopically noted veneer delamination from the core, core fracture, shear within the veneer porcelain, or a combination thereof. A Kruskal-Wallis test was used to determine if a significant difference (alpha=.05) in load to failure existed between the 4 groups, and a Mann-Whitney test with a Bonferroni correction (P<.0125) was used for multiple comparisons. A Weibull analysis was also used to estimate the Weibull modulus and characteristic failure for each group. RESULTS: All specimens exhibited edge chipping around the access openings. Some displayed larger chips within the veneering porcelain, and 4 zirconia crowns showed radial crack formation. There was a significant difference in load to failure among all groups with the exception of the alumina intact and repaired specimens (P=.695). The alumina crowns generally showed fracture of the coping with the veneering porcelain still bonded to the core, whereas the zirconia copings tended not to fracture but experienced veneering porcelain delamination. CONCLUSION: Endodontic access through all-ceramic crowns resulted in a significant loss of strength in the zirconia specimens but not in the alumina specimens.

Aluminum Oxide↗
PubMed2006

Influence of remaining coronal tooth structure location on the fracture resistance of restored endodontically treated anterior teeth.

STATEMENT OF PROBLEM: A restored endodontically treated tooth is less likely to fracture when there is axial tooth structure between the core base and preparation finish line. However, an accurate prognosis requires knowing whether fracture resistance depends on a complete circumferential distribution of tooth structure or tooth structure in a specific location related to the applied force. PURPOSE: This in vitro study investigated the fracture resistance of restored endodontically treated teeth when residual axial tooth structure was limited to one half the circumference of the crown preparation. MATERIAL AND METHODS: Fifty extracted maxillary anterior teeth were sectioned 18 mm from their apices, endodontically treated, and divided into 5 groups of 10 teeth each. Four groups were prepared with full shoulder crown preparations having axial wall heights of 2 mm around the preparation circumferences. In 3 of the groups with axial tooth structure, one half of the axial tooth structure was removed, palatally, labially, or proximally, and groups were identified according to the site of retained coronal tooth structure. For the fifth group, all axial tooth structure was removed to the level of the preparation shoulder. Thus, in 1 group the axial walls were circumferential, 360 degrees around the preparations (Complete group), in 3 groups the axial walls were continuous for 180 degrees (Palatal, Labial, and Proximal groups), and the last group had no retained coronal tooth structure incisal to the finish line (Level group). All 50 prepared teeth were then restored with quartz fiber posts (Bisco), composite resin (Bisco) cores, and metal crowns. A universal testing machine compressively loaded the tooth specimens from the palatal at a crosshead speed of 0.5 cm/min at an angle of 135 degrees to the long axis of teeth until failure occurred. A survival analysis was conducted using a log-rank test followed by Holm-Sidak pairwise tests (alpha=.05) to detect significant differences in median failure load between groups. The mode of failure was determined by visual inspection of all specimens. RESULTS: The median failure load (P<.001) was 607 N, 782 N, 358 N, 375 N, and 172 N for the Complete, Palatal, Labial, Proximal, and Level groups, respectively. The predominant mode of failure was an oblique palatal to facial root fracture for the groups with remaining coronal tooth structure. In the Level group, post debonding was the predominant mode of failure. CONCLUSION: For restored endodontically treated teeth that do not have complete circumferential tooth structure between the core and preparation finish line, the location of the remaining coronal tooth structure may affect their fracture resistance.

Dental Restoration Failure↗
PubMed2006

Etodolac versus dexamethasone effect in reduction of postoperative symptoms following surgical endodontic treatment: a double-blind study.

OBJECTIVE: The purpose of this prospective study was to analyze the effect of etodolac versus dexamethasone in reducing postoperative pain in patients who had surgical endodontic treatment using a strict protocol. STUDY DESIGN: The study consisted of 90 patients (38 males and 52 females) referred for surgical endodontic treatment. All procedures were performed using a microsurgical technique with a strict protocol. Patients were randomly premedicated with placebo or with one of both protocols: either a single dose of oral dexamethasone, 8 mg, preoperatively and 2 single doses, 4 mg, 1 and 2 days postoperatively, or a single dose of etodolac, 600 mg, and 2 single doses, 600 mg, 1 and 2 days postoperatively. Pain was recorded at 8, 24, and 48 hours, as well as 7 days postoperatively, on a 1-10 scale. The influence of different variables on postoperative sequelae was analyzed. RESULTS: On a 1-10 scale, the mean values of pain report recorded were 3.8 +/- 2.9 (8 hours postoperatively), 2.93 +/- 2.4 (24 hours), 2.31 +/- 2.2 (48 hours), and 1.4 +/- 0.9 (7 days postoperatively). One day postoperatively, 41.8% of the patients reported no or very mild pain (score 1 or 2), whereas after 7 days, 87.9% reported no or very mild pain (score 1 or 2). Both etodolac and dexamethasone had a significant effect of reducing postoperative pain in patients who had surgical endodontic procedure compared with placebo (P < or = .001). CONCLUSION: Postoperative pain following endodontic surgical treatment is not uncommon. Etodolac as well as dexamethasone might serve as a pain relief measure for postoperative pain in these patients.

Adolescent↗
PubMed1991

Prevalence and quality of endodontic treatment in an elderly urban population of Switzerland.

Little oral health data on the elderly are available in Switzerland. This study assessed endodontic findings in 66-yr-old residents of the city of Zurich using intraoral radiographs. Of the 143 volunteers having a total of 2004 natural teeth, 78% had at least one endodontically treated tooth. Twenty percent of all teeth were root filled, two thirds of them being in the upper jaw. Sixty-four percent of the root fillings were judged insufficient and 8.5% of all teeth showed periapical radiolucencies, most of the latter (73%) being associated with insufficient root canal treatments. Ninety-eight percent of the root-filled teeth had intracanal retentive devices. Fifty-two percent of the teeth with insufficient root fillings were judged not to need revision, 37% needed revision, 9% needed apicectomy, and 2% were ready for extraction. The considerable endodontic treatment needs of the elderly can only be reduced by an improvement of quality of initial endodontic treatment.

Aged↗
PubMed1996

New directions in surgical endodontics; immediate implantation into an extraction site.

Endodontic surgical procedures may reveal compromising factors that indicate a modification of the treatment (e.g. tooth extraction, root amputation, etc.). To take advantage of the osseous height and width, as well as the natural tooth angulation, immediate placement of implants after extraction is a reasonable alternative treatment. In this study, 32 titanium alloy implants were inserted immediately after extraction of teeth diagnosed during endodontic surgery as having root fractures, perforations, or endodontic-periodontal complications. After 4 to 6 months of osseointegration, only one implant failed to integrate, and the remaining implants were prosthetically restored. Sixteen months after occlusal loading, bone loss was approximately 1.5 mm for the 31 implants remaining. It seems that the immediate placement of implants following tooth extraction due to endodontic complications is a reliable procedure.

Adult↗
PubMed1997

Occurrence of Prevotella nigrescens and Prevotella intermedia in infections of endodontic origin.

The occurrence of Prevotella intermedia and Prevotella nigrescens in endodontic infections was studied using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of whole cell protein to distinguish between the species. Previous studies have shown an association between black-pigmented bacteria (BPB) and endodontic infections and that Prevotella intermedia (previously known as Bacteroides intermedius) was the most commonly isolated BPB. Recently, however, strains identified as P. intermedia were shown to in fact be composed of two separate species, P. intermedia and P. nigrescens. Fifty-six strains of BPB isolated from endodontic infections and previously identified as P. intermedia were used in this study. Following SDS-PAGE, P. nigrescens showed a unique 18.6 kDa band that was used to differentiate P. nigrescens from P. intermedia. Of the 56 strains of BPB, 41 (73.2%) were identified as P. nigrescens and 15 (26.8%) as P. intermedia. This study confirms that P. nigrescens, and not P. intermedia, is the BPB most often isolated from infections of endodontic origin.

Amino Acid Sequence↗
PubMed1997

Comparison of triazolam, diazepam, and placebo as outpatient oral premedication for endodontic patients.

Triazolam and diazepam were compared as oral antianxiety agents in a randomized double-blind, placebo-controlled clinical study of 79 endodontic patients with elevated anxiety regarding endodontic treatment. Patients who scored > or = 10 on the Corah Dental Anxiety Survey received oral formulations of triazolam (0.25 mg), diazepam (5 mg), or placebo. Before, during, and after the endodontic procedure, patients completed psychomotor tests and anxiety scales, and were evaluated for 24-h postoperative recall. In comparison with diazepam and placebo, triazolam was significantly better for decreased anxiety (p < 0.05), impaired cognitive function (p < 0.05), patients' rating of drug effectiveness (p < 0.05), and amnesia to clinical events (p < 0.02) and pictures (p < 0.03). Diazepam showed similar trends compared with placebo, but to a lesser degree. Diazepam also had a much longer recovery period. No adverse effects were noted with either drug. These findings suggest that orally administered triazolam (0.25 mg) is a safe and more effective anxiolytic agent than diazepam (5.0 mg) for endodontic patients.

Adjuvants, Anesthesia↗
PubMed1999

Development of a clindamycin-impregnated fiber as an intracanal medication in endodontic therapy.

The effectiveness of traditional endodontic intracanal medications in reducing bacterial numbers and preventing acute flare-ups and pain continues to be questioned. In the present study, a new local delivery device was developed that releases a substantive dose of clindamycin into root canals. Clindamycin-impregnated ethylene vinyl acetate (EVA) fibers were produced, and the sensitivity of common endodontic microbes to the fibers were established. An in vitro model was developed to persistently infect 32 extracted human teeth with endodontic pathogens to test the efficacy of the clindamycin/EVA fibers in reducing the number of colony-forming units. The clindamycin/EVA fibers were shown to be effective in reducing growth of common endodontic microbes on blood agar plates, and in significantly reducing growth of Prevotella intermedia, Fusobacterium nucleatum, and Streptococcus intermedius in extracted human teeth, thus indicating merit in further exploring the potential of these fibers as intracanal medications.

Anti-Bacterial Agents↗
PubMed1999

Evaluation of the combination of flurbiprofen and tramadol for management of endodontic pain.

Effective management of endodontic pain represents a continuing challenge. In this study, we evaluated the efficacy of flurbiprofen and a novel centrally acting analgesic, tramadol, alone and in combination, for reducing pain in endodontic emergency patients. Patients (n = 49) were administered a local anesthetic and underwent pulpectomy. They were then administered, on a double-blind basis, either: (i) placebo (one capsule to start and then every 6 h); (ii) flurbiprofen (100 mg loading dose and then 50 mg every 6 h); (iii) tramadol (100 mg loading dose and then 100 mg every 6 h); or (iv) the combination of flurbiprofen and tramadol (as above). Pulpectomy combined with placebo medication resulted in a 50% reduction in pain by 24 h (p < 0.01). Patients treated with flurbiprofen and tramadol reported less pain, compared with placebo treatment at 6 and 24 h (p < 0.01 for both). These results suggest that a nonsteroidal anti-inflammatory drug/opiate combination, together with endodontic therapy, may be useful in the management of endodontic pain.

Analgesics, Opioid↗
PubMed1998

The odontogenic keratocyst: a potential endodontic misdiagnosis.

Odontogenic keratocysts manifest themselves as radiolucencies that can appear anywhere in the maxilla or mandible, including periradicular areas; they may thus masquerade as lesions of endodontic origin. This retrospective study examined 239 odontogenic keratocysts received by the Oral Pathology Laboratory at Temple University School of Medicine over a 3-year period. Twenty-one (9%) of the cysts received were located periradicularly; of these 21, 12 (57%) were associated with nonvital or endodontically treated teeth and thus mimicked lesions of endodontic origin. Because of its aggressive nature and tendency to recur, the periradicular odontogenic keratocyst should be included in the differential diagnosis of lesions that are refractory to endodontic treatment.

Adult↗
PubMed1999

Vertical root fracture in endodontically versus nonendodontically treated teeth: a survey of 315 cases in Chinese patients.

OBJECTIVE: The purpose of this study was to compare endodontically versus nonendodontically treated teeth with respect to clinical features, including patient age and gender and tooth types of vertical root fractures. STUDY DESIGN: A total of 315 consecutive cases of vertical root fracture occurring in 274 Chinese patients during a 1 3-year period were reviewed. Age and gender, as well as tooth type and root distribution of vertical root fractures, were presented and compared in endodontically versus nonendodontically treated teeth. RESULTS: Most patients (87%) had 1 fractured tooth; the others had 2 or 3 fractured teeth. Of all vertical root fractures, 40% occurred in nonendodontically treated teeth. In comparison with those in endodontically treated teeth, vertical root fractures in nonendodontically treated teeth tended to occur in patients with a higher mean age (55 years vs. 51 years) and were more frequent in male patients (78% vs. 58%). Vertical root fractures occurred in nonendodontically treated teeth more often in molars (84% vs. 53%), less often in premolars (16% vs. 33%), and seldom in anteriors (1 tooth vs. 27 teeth). CONCLUSIONS: Vertical root fractures in nonendodontically treated teeth are not uncommon and comprise a large proportion of such fractures in Chinese patients. Differences between endodontically and nonendodontically treated teeth in patient age and gender, as well as in tooth types of vertical root fractures, were demonstrated.

Adult↗
PubMed2003

Detection of Filifactor alocis in endodontic infections associated with different forms of periradicular diseases.

Recent molecular studies have expanded the list of suspected endodontic pathogens. The aim of this study was to evaluate the occurrence of Filifactor alocis in primary endodontic infections associated with different forms of periradicular diseases. Identification by nested polymerase chain reaction was performed in root canal samples from teeth associated with either asymptomatic periradicular lesions or acute apical periodontitis. Samples were also taken by aspiration of purulent exudate associated with acute apical abscesses. DNA extracted from the samples was initially amplified using universal 16S rDNA primers followed by a second round of amplification using the first PCR products to detect a specific fragment of F. alocis 16S rDNA. F. alocis was detected in 12/21 (57.1%) root canal samples from teeth showing asymptomatic periradicular lesions and in 3/10 (30%) samples taken from root canals associated with acute apical periodontitis. This species occurred in 8/19 (42.1%) pus aspirates obtained from abscessed teeth. In general, F. alocis was detected in 23/50 (46%) samples taken from endodontic infections. These findings suggest that F. alocis is involved in the etiology of different forms of periradicular diseases and has the potential to be an endodontic pathogen.

Adolescent↗
PubMed2004

Contemporary dental practice in the UK: aspects of direct restorations, endodontics and bleaching.

OBJECTIVES: To investigate by questionnaire, the use and selection of materials and techniques for the placement of direct restorations and the provision of endodontics and bleaching by dental practitioners in the North West of England and Scotland. METHODS: A questionnaire was sent to 1,000 general dental practitioners selected at random from dentists in Scotland and the North West of England. Non-responders were sent another questionnaire after a period of 4 weeks had elapsed. RESULTS: A total of 701 usable questionnaires were returned, giving a response rate of 70%. The most commonly used material for the restoration of Class II cavities in premolar and permanent molar teeth was amalgam (n = 605, 86%) and (n = 634, 90%) respectively. Many practitioners (n = 419, 60%) felt amalgam should continue to be used but a majority (n = 374, 66%) remained unconvinced about the merits of amalgam bonding. A minority (n = 63, 9%) of practitioners used predominantly directly placed resin composite rather than amalgam to restore Class II cavities in premolar and permanent molar teeth. Home-based vital bleaching was provided by a significant number (n = 245, 35%) of practitioners with only 18% (n = 123) providing practice-based bleaching. The most commonly used endodontic obturation technique was cold lateral condensation (n = 527, 75%) with 61% (n = 425) of respondents not using rubber dam routinely for endodontics. CONCLUSIONS: For the practitioners in this survey, amalgam was the most frequently selected direct restorative material. Few practitioners used amalgam bonding let alone direct resin composite for posterior restorations. Home-based rather than practice-based bleaching procedures were preferred, as were more traditional endodontic obturation techniques.

Dental Materials↗
PubMed2006

Microbiological evaluation of photo-activated disinfection in endodontics (an in vivo study).

OBJECTIVE: To determine the microbiological effect of photoactivated disinfection (PAD) as an adjunct to normal root canal disinfection in vivo. DESIGN: A randomised trial carried out in general dental practice. SUBJECTS AND METHODS: Patients presenting with symptoms of irreversible pulpitis or periradicular periodontitis requiring endodontic therapy were selected at random. A microbiological sample of the canal was taken on accessing the canal, after conventional endodontic therapy, and finally after the PAD process (photosensitiser and light) had been carried out on the prepared canal. All three samples from each canal were plated within 30 minutes of sampling and cultured anaerobically for five days. Growth of viable bacteria was recorded for each sample to determine bacterial load. RESULTS: Thirty of the 32 canals were included in the results. Cultures from the remaining two did not reach the laboratory within the target time during which viability was sustained. Of the remaining 30, 10 canals were negative to culture. These were either one of the canals in multi rooted teeth where the others were infected or where a pre-treatment with a poly-antibiotic paste had been applied to hyperaemic vital tissue. Sixteen of the remainder were negative to culture after conventional endodontic therapy. Three of the four which had remained infected cultured negative after the PAD process. In the one canal where culturable bacteria were still present, a review of the light delivery system showed a fracture in the fibre reducing the effective light output by 90%. CONCLUSIONS: The PAD system offers a means of destroying bacteria remaining after using conventional irrigants in endodontic therapy.

Adolescent↗
PubMed2000

Comparison of observer performance in determining the position of endodontic files with physical measures in the evaluation of dental X-ray imaging systems.

OBJECTIVE: To examine the feasibility of substituting observers determining the accuracy of endodontic measurements for measurements of physical qualities in comparison of digital imaging systems. METHODS: Sensors from six digital imaging systems were compared for signal-to-noise ratio (SNR), modulation transfer function (MTF) and detective quantum efficiency (DQE). A total of 45 canals in teeth from human cadavers were instrumented to their apical foramina. Endodontic files, ranging in size from size 8 to size 20, were glued in place at random distances from the apical foramina spanning a range of +/- 3 mm. The teeth were imaged with the six digital systems and dental X-ray film. Fifteen dentists independently measured the distance from the end of the file to the apical foramen. Results were expressed as the measurement error. Measurement error was compared to SNR, MTF and DQE for each digital system. RESULTS: CDR (Schick, New York, NY, USA), Digora (Sordex, Helsinki, Finland) and Dexis (Provision Dental Systems, Palo Alto, CA, USA) produced the highest SNR values followed closely by RVG-4 (Trophy, Croissy-Beavborg, France). Sens-A-Ray (Dent-X/Regam Medical Systems, Sundsvall, Sweden), Dexis and the RVG-4 produced the best MTF results. Dexis had the greatest DQE. The mean measurement errors (in mm) were: Film 0.65, Dexis 0.69, CDR 0.71, RVG-4 0.74, Digora 0.89, Sens-A-Ray 0.97, and Visualix-2 (Gendex, Monza, Italy) 0.98. CONCLUSIONS: Digital systems closely approximate film in their accuracy when used for endodontic measurement providing that the assessment instruments have similar resolving power. DQE was the best physical predictor of system accuracy when compared with endodontic length measurements. MTF and SNR alone did not accurately predict observer precision.

Cadaver↗