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This article presents a technique for making and using disposable standardized silicone stops. The stops have several diameters, colors, and thicknesses in order to make nonsurgical endodontics more efficient and improve the quality of therapy.
Radiovisiography was compared clinically to conventional D-speed and E-speed radiographs viewed with X 2 magnification using the mesiobuccal root of maxillary molars of 22 patients. Clarity of size 8 and 10 endodontic file tips in relation to the radiographic apex was the object of comparison. Five images of radovisiography, (original, enhanced, negative-to-positive mode), were compared to D-speed and E-speed radiographs. D-speed radiographs were also compared to E-speed radiographs. D-speed radiographs were statistically superior to all five radiovisiography images. Four of the radiovisiography images were equivalent to E-speed radiographs. D-speed radiographs provided superior recognition of small file tips when compared to E-speed radiographs 100% of the time. Accurate identification of the small file tips was achieved on 95% of D-speed and 70% of E-speed radiographs. With radiovisiography, identification was achieved on 95% of the zoom images in the negative-to-positive mode, 86% of enhanced, 82% of standard zoom, and 77% of the images in negative-to-positive conversion.
This study compared the sealing capacity of three different endodontic gutta-percha filling techniques. Forty-seven upper central incisors with straight canals were instrumented and randomly divided into three equal groups of 14. An additional group of five teeth with unobturated canals served as positive controls. The following gutta-percha filling techniques were evaluated: Trifecta (group A), lateral condensation (group B), and a combination of SuccessFil gutta-percha and lateral condensation (group C). Tubli-Seal was used as a sealer. The teeth were radiographed in mesiodistal and bucco-lingual directions to study the quality of the filling. Afterward, the teeth were immersed in India ink and subsequently cleared. The maximal depth of penetration was measured using a light microscope. The mean value of ink penetration for group A was 1.073 mm, for group B was 0.522 mm, and for group C was 0.765 mm. No statistically significant differences were seen among groups (p < 0.05).
Sodium hypochlorite, as an endodontic irrigant, poses problems including toxicity, odor, and discoloration of operatory items. An equally effective, but safer irrigant is desirable. Therefore, we compared the antimicrobial activity of 2.0% chlorhexidine gluconate with that of 5.25% sodium hypochlorite in an in vitro root canal system. Freshly extracted human teeth with pulpal pathosis were instrumented using chlorhexidine, sodium hypochlorite, or saline as irrigants. Microbiological samples were taken from the teeth immediately after accessing the canal, after instrumentation and irrigation, and after standing in an anaerobic atmosphere for 24 h. Irrigation with chlorhexidine or sodium hypochlorite significantly reduced the numbers of postirrigant positive cultures and colony-forming units compared with saline-irrigated teeth. The number of postirrigant positive cultures and the number of colony-forming units in positive cultures obtained from chlorhexidine-treated teeth were lower than the numbers obtained from sodium hypochlorite-treated teeth, but the differences were not statistically significant.
Cutting efficiency of 24 different types of endodontic hand instruments, which are primarily designed for a rotary (reaming) working action, was investigated under standardized conditions. With a computer-driven testing device, resin specimens with simulated cylindrical canals were instrumented using a defined working motion simulating the clinical use of the instruments. Maximum penetration depth was the criterion for cutting efficiency. Sample size was 12 instruments for each type and size (#25 and #35). Nitinol K-files showed the least cutting efficiency. Stainless steel reamers and especially K-files showed better cutting efficiency than Nitinol K-files. Flexible stainless steel instruments displayed the best results. With regard to cutting efficiency, flexible stainless steel instruments were clearly superior to stainless steel reamers and K-files, and especially to Nitinol K-files.
Exclusion of infected root tips, dentinal debris, and inflammatory tissue from the maxillary sinus during endodontic surgery is imperative. A simple technique for preventing accidental root tip intrusion into the maxillary sinus using a 6-0 suture and needle and a hole prepared in the root tip with a #2 round bur prior to apicoectomy is presented.
The resistance to fracture of mandibular premolar roots before and after endodontic and restorative procedures was tested. Seven treatment groups were evaluated. A Universal testing machine was used to apply vertical and lateral (45-degree) forces. Overall, the untreated roots showed the highest resistance to fracture. Factors of importance to prevent fracture were found to be (a) the amount of remaining tooth structure; (b) strength of post and core; and (c) bonding between core material and dentin. These factors suggest that a composite core following the use of EDTA to remove the smear layer may be a successful treatment when sufficient tooth structure remains.
This article reviews the role chloroform has played in dentistry and describes an occupational health clinical investigation into the possible hazards of chloroform use in the operatory. Due to a Food and Drug Administration ban on drugs and cosmetics containing chloroform, there has been some confusion as to whether the use of chloroform in the practice of dentistry is considered unsafe or has been prohibited. Utilizing common endodontic treatment methods employing chloroform, this study reports no negative health effects to the dentist or assistant and air vapor levels well below Occupational Health and Safety Administration mandated maximum levels. The report concludes that, with careful and controlled use, chloroform can be a useful adjunct in the practice of dentistry. The Food and Drug Administration has no jurisdiction over a dentist's use of chloroform in clinical practice and has not proven that chloroform is a human carcinogen.
The aim of this study was to determine the structure and the ultrastructure of the organo-mineral coating retained by endodontic reamers. Premolars extracted for orthodontic reasons were instrumented using Rispi Micromega reamers mounted on a counterangle Giromatic. One group of premolars was instrumented without irrigation, a second group was instrumented with irrigation using physiological saline, and a third group was instrumented with irrigation using Dakin. After instrumentation, the specimens were observed by scanning electron microscopy. Two microscopic techniques were used for each specimen. Secondary electron imaging was used to examine the amount of material adhering to the surfaces of the Rispi reamers after instrumentation, whereas backscattered electron imaging was used to determine the variation in the organo-mineral composition of the smear layer adhering to the reamers. The deeper layer adhering to the surface of the reamers was predominantly organic in nature no matter which instrumentation or irrigation technique was used.
Chloroform has been the most widely used solvent in endodontics, but due to concerns about its safety, alternatives have been sought. The purpose of this study was to compare the effectiveness of gutta-percha removal and time of retreatment between halothane and chloroform used as solvents. Thirty mandibular premolars were prepared, obturated, and stored in a humidor for 14 months, after which they were randomly divided into two groups for retreatment. The teeth were retreated using either halothane or chloroform as the solvent. The time of retreatment was measured to the nearest minute. Retreatment was deemed complete when there was no evidence of gutta-percha or sealer on the files or paper points. Teeth were split longitudinally and photographed. The resulting slides were projected, the canals traced, and the areas of the canal, gutta-percha, and sealer were measured using a sonic digitizer. The results were analyzed statistically by t test. The results showed no significant difference in gutta-percha removal between the two groups. The chloroform group took significantly less time to retreat than halothane (7.7 min. versus 10.8 min, respectively).
Radiovisiography is a new intraoral radiographic imaging system. In this in vitro investigation, radiovisiography was compared with conventional radiographs viewed with x2 magnification. Twenty-five extracted maxillary molars were evaluated for clarity of size 8 and 10 endodontic file tips in relation to the radiographic apex. Five images of radiovisiography were compared with D-speed and E-speed radiographs: original, enhanced, negative-to-positive, standard zoom, and zoom in the negative-to-positive mode. D-speed radiographs were also compared with E-speed radiographs. Zoom in the negative-to-positive mode was statistically equivalent to D-speed radiographs (p = 0.264) and superior to E-speed radiographs (p < 0.001). The standard zoom was also superior to E-speed radiographs (p = 0.025). D-speed radiographs were statistically superior to E-speed radiographs; being judged better than E-speed 90% of the time. Accurate identification of the position of the tips of size 8 and 10 files was achieved on all D- and E-speed radiographs with the use of magnification.
One hundred six patients with pretreatment pain presenting for endodontic treatment participated in a controlled double blind study. After root canal therapy, the patients were given an intraoral intramuscular injection of either a saline placebo or various dosages of dexamethasone. Posttreatment pain incidence and severity were evaluated at 4, 8, 24, 48, and 72 h. Injection of the various dosages of dexamethasone, taken as a group, was shown to significantly reduce the severity of pain at 4 and 8 h, and 0.07 to 0.09 mg/kg dosage alone significantly reduced pain at 8 h. Patients who received dexamethasone took significantly fewer posttreatment pain medications than those who received the placebo. Although there was a trend toward a reduction in the incidence of posttreatment pain for patients who received dexamethasone, the difference was not statistically significant.
The microflora and humoral immune response in tissue from the periodontal pockets and root canals of five teeth with endodontic-periodontic lesions were examined. We found more microbes in the periodontal pockets than in the root canals. The flora in the periodontal pockets was dominated by rods and motile organisms, whereas that in the root canals was largely rods and cocci. We detected no spirochetes in the root canals. The cultivable microflora in the periodontal pockets comprised a high number of different species of bacteria, whereas those in the root canals included only a small number of species. There was no correlation between microbial isolates and antibody titer in the apical tissues or periodontal pockets. We conclude from these studies that the microflora of infected root canals is simple and limited, and that the local humoral immune response does not seem to affect the pathogenesis of disease directly.
A laboratory study was performed on Peeso drills to determine their physical dimensions, torsional performance, and metallurgical properties. Samples were measured from each of sizes #1 to #6 of Peeso drills (type P) and sizes #009 to #023 of Peeso drills (type B-1) from the two manufacturers that distribute these instruments in the United States. They were also tested in clockwise and counterclockwise torsion using a digital torque meter instrument. It was not possible to evaluate completely some type P drills of size #4 and larger or type B-1 drills of size #016 and larger because the torsional moments exceeded the capacity of the test instrument. Scanning electron microscopic examination confirmed visual observations that the stainless steel Peeso drills exhibited ductile torsional fracture, in contrast to the carbon steel Peeso drills which fractured in a relatively brittle manner. The carbon steel Peeso drills exhibited a much greater tendency for torsional fractures in the bur head, along with considerably smaller values of angular deflection at separation compared to the stainless steel Peeso drills. This study is part of a continuing investigation to establish standards for all rotary endodontic instruments.
The purpose of this study was to compare the pain-reducing efficacy of dexamethasone and ketorolac tromethamine when used as an intracanal medication, with oral ibuprofen and a placebo. An additional objective was to establish if any relationship exists between the incidence and severity of pretreatment pain and the incidence and severity of postinstrumentation pain. A total of 48 patients who presented to the University of Illinois postgraduate endodontic clinic were invited to participate. Patients were randomly assigned to 1 of 4 groups: oral ibuprofen, placebo, dexamethasone, or ketorolac tromethamine. Patients were asked to evaluate their pretreatment pain when they presented to the clinic with a Visual Analog Scale. The root canal treatment was performed in two appointments. The first appointment consisted of cleansing and shaping of the canal/s and placement of an intracanal medication. All teeth were closed with a sterile cotton pellet and IRM. Each patient was sent home with a Visual Analog Scale to fill out at 6, 12, 24 and 48 h after initiation of therapy. At the 12-h period, both dexamethasone and ketorolac provided statistically significant better pain relief than placebo. At the 24-h period, only ketorolac demonstrated better pain relief than the placebo. There were no statistically significant differences among the groups at 6 and 48 h. Although ibuprofen pain ratings were less than the placebo at all time points, the reduction was not significant. In addition, no significant differences were demonstrated between ibuprofen and either dexamethasone or ketorolac.
The purpose of this paper was to examine the varied impact of the pathological spread of dental sepsis into the adjacent maxillary sinus. This complex of tissue destruction is called Endo-Antral Syndrome; the usual radiographic diagnostic features are identified in the paper. The four different cases presented serve to illuminate a few of the many diagnostic and treatment challenges involved. Emphasis is placed on the utilization of a keen sense of wariness when endodontically treating maxillary posterior teeth whose apexes are close to the sinus. Dental examination should include an appraisal of antral health prior to root canal therapy to best plan treatment and to establish a base line against which to judge subsequent developments.
A clinical study was done on 36 original cases of vertical root fractures along with the data gathered from 32 cases published previously in the literature. Vertical root fractures most frequently occur in posterior teeth in patients between 45 and 60 yr of age. The average elapsed time between the endodontic treatment and the subsequent diagnosis of vertical fracture was found to be approximately 10 yr. The evidence and symptoms most often found are mild pain in the area of the fractured tooth often accompanied by swelling and fistula, along with a deep pocket in just one area of the attachment surrounding the tooth. The sign most often revealed by X-ray is a radiolucent periradicular band.
The objective of this study was to determine whether significant differences exist between the mechanical properties of human dentin from treated pulpless teeth and dentin from normal vital teeth. Dentin specimens (n = 262) were obtained from 54 freshly extracted normal vital human teeth and 24 treated human pulpless teeth. These specimens were subjected to different experimental conditions (wet, air dried, desiccated, and rehydrated). Compression, indirect tensile, and impact tests were conducted to measure the mechanical properties of those specimens. All data obtained were analyzed with t tests. The results showed that the dehydration of dentin increases the Young's modulus, proportional limit (in compression), and especially the ultimate strength (in both compression and tension). Substantial dehydration changes the fracture characteristics of dentin specimens under static compressive and indirect tensile loadings. The measurements of impact-breaking energies of desiccated dentin were not found to be significantly decreased. The compressive and tensile strengths of dentin from treated pulpless teeth obtained in this study do not appear to be significantly different from those of normal dentin (p > 0.05), while the mean values of Young's modulus and proportional limit in compression tests appear to be lower. Fifty percent of the dentin specimens from treated pulpless teeth exhibit greater plastic deformation than normal dentin in compression. The results of this study do not support the theory that dehydration after endodontic treatment per se weakens dentin structure in terms of compressive and tensile strengths. Other mechanical properties of treated pulpless teeth, however, may not be the same as those of normal vital teeth.