Showing papers in "International Endodontic Journal in 2002"

Mechanisms involved in the resistance of Enterococcus faecalis to calcium hydroxide

Abstract: involved in the resistance of Enterococcus faecalis to calcium hydroxide. International Endodontic Journal, 35 , 221‐228, 2002. Aim This study sought to clarify the mechanisms that enable E. faecalis to survive the high pH of calcium hydroxide. Methodology E. faecalis strain JH2-2 was exposed to sublethal concentrations of calcium hydroxide, with and without various pretreatments. Blocking agents were added to determine the role of stress-induced protein synthesis and the cell wall-associated proton pump. Results E. faecalis was resistant to calcium hydroxide at a pH of 11.1, but not pH 11.5. Pre-treatment with calcium hydroxide pH 10.3 induced no tolerance to further exposure at pH 11.5. No difference in cell survival was observed when protein synthesis was blocked during stress induction, however, addition of a proton pump inhibitor resulted in a dramatic reduction of cell viability of E. faecalis in calcium hydroxide. Conclusions Survival of E. faecalis in calcium hydroxide appears to be unrelated to stress induced protein synthesis, but a functioning proton pump is critical for survival of E. faecalis at high pH.

Apical limit of root canal instrumentation and obturation, part 2. A histological study.

Abstract: The results of an in vivo histological study involving apical and periapical tissues following root canal therapy after different observation periods demonstrated the most favourable histological conditions when the instrumentation and obturation remained at or short of the apical constriction. This was the case in the presence of vital or necrotic pulps, also when bacteria had penetrated the foramen and were present in the periapical tissues. When the sealer and/or the gutta-percha was extruded into the periapical tissue, the lateral canals and the apical ramifications, there was always a severe inflammatory reaction including a foreign body reaction despite a clinical absence of pain.

Root and canal morphology of Thai maxillary molars

Abstract: Aim To investigate the root and canal morphology of 268 maxillary permanent molars collected from an indigenous Thai population.Methodology The cleaned teeth were accessed, the pulp dissolved by sodium hypochlorite under ultrasonication, and the pulp system injected with Indian ink. The teeth were rendered clear by demineralization and immersion in methyl salicylate. The following observations were made: (i) number of roots and their morphology; (ii) number of root canals per root; (iii) root-canal configuration in each root using Vertucci's classification with additional modifications; and (iv) presence and location of lateral canals and intercanal communications.Results All the maxillary first and second molars had three separate roots. Only, half (51%) of the maxillary third molars had three separate roots; the other half had fused or conical roots. The majority of the distobuccal (98.1-100%) and palatal (100%) roots had type I canals. Over half of the mesiobuccal roots of first (65%) and second (55%) molars had two canals. The most common (44.2%) canal configuration in mesiobuccal roots of first molars was type IV (two canals, two foramina). A variety of canal types were found in the mesiobuccal roots of second molars. Maxillary third molars showed the greatest diversity of canal morphology. There was an increase in the prevalence of lateral canals towards the apical part of the roots and intercanal communications were present in 16% of each of first, second and third Thai maxillary molars.Conclusions The mesiobuccal roots of Thai maxillary molars possessed a variety of canal system types. Over 50% of the first molars had a second mesiobuccal canal. The palatal and distobuccal canals mainly had type I canals. Only, a small proportion (7.3-13.3%) of the roots exhibited lateral canals which were the most common in the apical third.

Periapical health related to the quality of coronal restorations and root fillings.

Abstract: Hommez GMG, Coppens CRM, De Moor RJG. Periapical health related to the quality of coronal restorations and root fillings. International Endodontic Journal, 35, 680^689, 2002. Aim To evaluate the impact of the quality of coronal restorations scored on a clinical and radiographic basis and the quality of root ¢llings on periapical health. Methodology Periapical radiographs were taken of 745 root-¢lled teeth, randomly selected from patients attending the Ghent University Dental School. The teeth had not received restorative treatment in the previous year. The coronal status was scored both clinically according to modi¢ed Ryge’s criteria, and radiographically by evaluating the presence of signs of marginal leakage or decay. The quality of the root ¢lling was scored according to criteria of length and homogeneity and the periapical status was categorized on the basis of presence or absence of radiographic signs of apical periodontitis. The relationship between coronal status, quality of root ¢lling and periapical health was determined. The data were analyzed using w 2 test, Odds ratio, Spearman’srS and logistic regression. Results Thirty-three percent of the teeth had apical periodontitis as diagnosed radiographically. Teeth with good and poor coronal restorations scored clinically had apical periodontitis in 31.1 and 36.8%, respectively; this diierence was not statistically signi¢cant. The quality of the coronal restorations scored radiographically had a statistically signi¢cant in£uence on the periapical condition (P < 0.001) with apical periodontitis in 23.8 and 49.1%, respectively, for acceptable and unacceptable restorations. Marginal decay did not in£uence the periapical status. Teeth restored without a base under the coronal ¢lling had apical periodontitis in 41.3%, whereas teeth with a base had signi¢cantly less (P < 0.005) apical periodontitis (25.9%). Composite-restored teeth exhibited apical periodontitis in 40.5% of cases whilst amalgam-restored teeth had apical periodontitis in 28.4% of cases; this diierence was statistically signi¢cant (P < 0.01). Root-canal posts had no in£uence on periapical health. The length and homogeneity of the root-canal ¢llings had a signi¢cant in£uence (P < 0.01 and P < 0.001, respectively) on the presence of apical periodontitis, as well as the quality of the coronal restoration scored radiographically (P < 0.001). Conclusion The importance of a good coronal restoration, as well as of a good root ¢lling should be emphasized as the technical quality of both in£uencing the periapical status.

Effects of instrumentation, irrigation and dressing with calcium hydroxide on infection in pulpless teeth with periapical bone lesions.

Abstract: Peters LB, van Winkelhoff A-J, Buijs JF, Wesselink PR. Effects of instrumentation, irrigation and dressing with calcium hydroxide on infection in pulpless teeth with periapical bone lesions. International Endodontic Journal , 35 , 13‐21, 2002. Aim The aim of this study was to evaluate the fate of microorganisms in root canals of teeth with infected pulps and periapical bone lesions with and without the use of calcium hydroxide medication. Methodology Endodontic samples were cultured and microorganisms were counted and identified in 43 teeth before (sample 1) and after (sample 2) treatment during the first visit and before (sample 3) and after (sample 4) treatment during the second visit. In the first visit teeth were instrumented and half of the teeth were filled with a thick slurry of calcium hydroxide in sterile saline. The other teeth were obturated with gutta-percha and AH-26 sealer. After 4 weeks the teeth with calcium-hydroxide were accessed again and after microbiological sampling they were obturated with gutta-percha and AH-26 sealer. Results The mean total colony forming unit (CFU) counts of positive samples dropped significantly as a result of canal preparation during the first visit from 1.0 × 10 6 to 1.8 × 10 3 (between samples 1 and 2) but increased to 9.3 × 10 3 in the period between the two visits (sample 2 and 3). There was no difference in mean total CFU counts of positive samples between the end of the first (sample 2) and the end of the second visit (sample 4). The most frequently isolated species were Prevotella intermedia , Capnocytophaga spp., Actinomyces odontolyticus , Propionibacterium acnes and Peptostreptococcus micros . Conclusions Although a calcium hydroxide paste was placed in the prepared canals, the number of positive canals had increased in the period between visits. However, the number of microorganisms had only increased to 0.93% of the original number of CFU (sample 1). It is concluded that a calcium hydroxide and sterile saline slurry limits but does not totally prevent regrowth of endodontic bacteria.

Periapical healing of endodontically treated teeth in one and two visits obturated in the presence or absence of detectable microorganisms

Abstract: Peters LB, Wesselink PR. Periapical healing of endodontically treated teeth in one and two visits obturated in the presence or absence of detectable microorganisms. International Endodontic Journal, 35, 660^667, 2002. Aim The purpose of the present study is to evaluate the healing of periapical lesions of teeth with positive and negative canal cultures at the time of obturation, and to evaluate the periapical healing of teeth treated in one visit (without) or in two visits with an interappointment dressing of calcium hydroxide. Methodology Thirty-nine patients received rootcanal treatment. In the ¢rst visit, teeth were instrumented, and 18 of these teeth were ¢lled (after microbiological sampling) with calcium hydroxide in sterile saline. The other 21 teeth were obturated with gutta-percha and AH-26 sealer after microbiological sampling. Four weeks later, the teeth with calcium hydroxide were accessed again and after microbiological sampling they were obturated with gutta-percha and AH-26 sealer. Healing of periapical radiolucency was recorded over a period up to 4.5 years. Results In both the treatment groups, the size of the periapical lesions reduced signi¢cantly during the follow-up period. Complete radiographic healing was observed in 81% of the cases in the one-visit group, and in 71% of the cases in the two-visit group. The probability of success increased continuously over time for both treatment groups. Seven out of eight cases (87.5%) that showed a positive root-canal culture at the time of obturation healed. The number of colony forming units (CFU) in six out of eight positive canals was <10 2 CFU mL � 1 . Conclusions Within the limitations of this study, no signi¢cant diierences in healing of periapical radiolucency was observed between teeth that were treated in one visit (without) and two visits with inclusion of calcium hydroxide for 4 weeks. The presence of a positive bacterial culture (CFU < 10 2 )a t the time of ¢lling did not in£uence the outcome of

Radiographic evaluation of the prevalence and technical quality of root canal treatment in a French subpopulation

Abstract: Aim This study was undertaken to examine the prevalence and technical quality of root fillings and the periapical status of endodontically treated teeth in a French subpopulation Methodology Full-mouth periapical radiographs were obtained from 208 consecutive adult patients seeking care within the dental service provided by the Hotel-Dieu in Paris The occurrence and technical quality of root fillings were assessed for each root according to the position and the density of the obturation The periapical status was evaluated using the Periapical Index Scoring System The type of coronal restoration and the presence of posts were also noted Results Of the 8743 roots included in the survey, 23% were root-filled An acceptable standard of treatment was found in 21% of roots with 16% of these cases associated with signs of periapical disease In roots with unacceptable root-fillings, 27% had periapical pathology A post was seen in 26% of the root-filled canals, with 29% of these cases associated with periapical pathology An intracoronal restoration existed in 30% of the filled roots, of which 22% exhibited a periapical lesion An extra-coronal restoration was present in 60% of the filled roots, of which 24% had radiographic signs of periapical pathology The remaining 10% of filled roots that had no coronal restoration were associated with periapical pathology in 33% of cases At least one periapical lesion was seen in 63% of the patients Conclusion The results demonstrate a high prevalence of root-filled teeth and poor technical quality of treatment Roots presenting with acceptable root fillings were associated with a lower prevalence of periapical pathology (P < 0001) Posts in roots were associated with periapical pathology significantly more than in roots without posts (P < 0001)

New perspectives on radicular cysts: do they heal?

Abstract: During the past few decades several authors have perpetuated the notion that nearly half of all periapical lesions are radicular cysts. A few studies, based on meticulous serial sectioning of periapical lesions retrieved in toto, have shown that the actual incidence of radicular cyst is only about 15% of all periapical lesions. Equally significant was the discovery in 1980 and recent confirmation that radicular cysts exist in two structurally distinct classes namely, those containing cavities completely enclosed in epithelial lining (periapical true cysts) and those containing epithelium-lined cavities that are open to the root canals (periapical pocket cysts). From a clinical point of view a periapical pocket cyst may heal after conventional root canal therapy whereas an apical true cyst is less likely to be resolved without surgical intervention.

Efficiency of rotary nickel-titanium FlexMaster instruments compared with stainless steel hand K-Flexofile--Part 1. Shaping ability in simulated curved canals.

Abstract: AIM The purpose of this study was to compare the shaping ability of FlexMaster rotary nickel-titanium instruments with stainless steel hand K-Flexofiles. This part of the two-part report describes the efficiency of these two instruments in simulated curved root canals. METHODOLOGY Simulated 28 degree- and 35 degree-curved canals were prepared by the FlexMaster instruments with a rotational speed of 250 rpm using a crown-down preparation technique. and by the K-Flexofiles using a reaming motion (n = 24 canals in each case). All canals were prepared up to size 35. The pre- and post-instrumentation images were recorded and assessment of the canal shape was completed with a computer image analysis program. The material removal was measured at 20 measuring points, beginning 1 mm away from the apex. Incidence of canal aberrations, preparation time,changes of working length and instrument failures were also recorded. RESULTS In comparison with stainless steel K-Flexofiles, the rotary FlexMaster instruments achieved bet-ter canal geometry, showed less canal transportation and created fewer canal aberrations in both the canal types. Two FlexMaster instruments were separated, and 15 FlexMaster instruments and 11 K-Flexofiles were permanently deformed during preparation. However, these differences were not significant (P > 0.05). Between both the canal types, FlexMaster was significantly faster (P < 0.001) than K-Flexofiles. Both instruments maintained a good working distance. CONCLUSIONS FlexMaster instruments prepared curved canals rapidly, and with minimal transportation towards the outer aspect of the curve.

Apical limit of root canal instrumentation and obturation, part 1. Literature review.

Abstract: One of the major controversies in root canal therapy concerns the apical limit of instrumentation and obturation. The results of longitudinal prognostic studies, basic anatomical knowledge of the apical third of the root canal, and the histological pulp reaction to caries progression demonstrated the presence of a vital apical pulp remnant, even in the presence of a periapical lesion. Finally necrosis and bacteria establish themselves in the periapical lesion. All valid prognosis studies confirm the practice of staying short of the apex with a homogeneous obturation to obtain the highest success rate of 90-94% (when done by or under supervision of specialists; results in the general population had a failure rate greater than 50%). The location of the apical foramen(ina) related to root canal treatment most frequently ends short of the apex, often by several millimetres.

The ferrule effect: a literature review.

Abstract: Stankiewicz NR, Wilson PR. The ferrule effect: a literature review. International Endodontic Journal, 35, 575^581, 2002. Literature review A ferrule is a metal ringor cap used to strengthen the end of a stick or tube. It has been proposed that the use of a ferrule as part of the core or arti¢cial crown may be of bene¢t in reinforcingroot-¢lled teeth. A review of the literature investigating this eiect is presented. The literature demonstrates that a ferrule eiect occurs owingto the arti¢cial crown bracingag ainst the dentine extendingcoronal to the crown marg in. Overall, it can be concluded that a ferrule is desirable, but should not be provided at the expense of the remaining tooth/root structure.

The dentinogenic effect of mineral trioxide aggregate (MTA) in short-term capping experiments.

Abstract: Aim The objective of the present experiment was to study the early pulpal cell response and the onset of reparative dentine formation after capping application of MTA in mechanically exposed pulps. Methodology Thirty-three teeth from three dogs, 12–18 months of age were mechanically exposed via class V cavities. Light pressure was applied to control haemorrhage. ProRoot MTA (Dentsply Simfra, Paris) was placed at the exposure site and light pressure was applied with a wet cotton pellet. The cavities were restored with amalgam and the pulpal tissue reactions were assessed by light and electron microscopy (transmission and scanning) after healing intervals of 1, 2 or 3 weeks. Results A homogenous zone of crystalline structures was initially found along the pulp–MTA interface, whilst pulpal cells showing changes in their cytological and functional state were arranged in close proximity to the crystals. Deposition of hard tissue of osteotypic form was found in all teeth in direct contact with the capping material and the associated crystalline structures. Formation of reparative dentine (tubular matrix formation in a polar predentine-like pattern by elongated polarized cells) was consistently related to a firm osteodentinal zone. Conclusions The present experiments indicate that MTA is an effective pulp-capping material, able to stimulate reparative dentine formation by the stereotypic defensive mechanism of early pulpal wound healing.

A scanning electron microscopic study of dentinal erosion by final irrigation with EDTA and NaOCl solutions

Abstract: AIM The purpose of this in vitro study was to examine dentinal erosion caused by final irrigation with EDTA and NaOCl. METHODOLOGY Twenty-five single-rooted human teeth were instrumented with rotary nickel-titanium Series 29 Profile Instruments. The teeth were divided into five groups and subjected to final irrigation as follows: group A, irrigated with 6% NaOCl (3 mL) for 2 min; group B, 15% EDTA (3 mL) for 1 min; group C, 15% EDTA (3 mL) for 1 min, followed by 6% NaOCl (3 mL) for 2 min; group D, 15% EDTA (3 mL) for 3 min and group E, 15% EDTA (3 mL) for 3 min, followed by 6% NaOCl (3 mL) for 2 min. Photomicrographs of dentinal walls were produced using a scanning electron microscope (3000 x) at 1, 3 and 6 mm from the apex. The amount of debris and dentinal tubule diameter were evaluated, and values were statistically analysed using one-way ANOVA and Fisher's PLSD test. RESULTS When the root canal was irrigated with 15% EDTA alone, the dentine had a smooth and plane appearance, and dentinal tubule orifices were regular and separated. When the root canal was irrigated with EDTA followed by NaOCL the dentine was eroded and the dentinal tubule orifices were irregular and rough. Dentinal tubule diameter increased to 3.43 +/- 0.23 microm in group C and to 3.93 +/- 0.44 microm in group E. Significant differences were observed between groups B and C, and between groups D and E (P < 0.05). However, more debris was removed by irrigation with EDTA followed by NaOCl than with EDTA alone (P < 0.05). CONCLUSIONS Final irrigation with 6% NaOCl accelerates dentinal erosion following treatment with 15% EDTA.

Cytotoxicity of resin-, zinc oxide-eugenol-, and calcium hydroxide-based root canal sealers on human periodontal ligament cells and permanent V79 cells.

Abstract: Aim The purpose of this study was to determine the cytotoxicity of three different types of root canal sealer on human periodontal ligament (PDL) cells and a permanent hamster cell line (V79 cells). Methodology Set specimens from two resin based sealers (AH26 and AHPlus), three zinc oxide–eugenol-based sealers (Canals, Endomethansone and N2) and one calcium hydroxide-based sealer (Sealapex) were eluted with culture medium for 1, 2, 3 and 7 days. Cytotoxicity was judged using tetrazolium bromide reduction assay on human primary PDL cells and V79 cells derived from a Chinese hamster. Results The results showed that elutes from resin-based, zinc oxide–eugenol-based, and calcium hydroxide-based sealers were cytotoxic to primary human PDL cultures and V79 cells. Calcium hydroxide-based sealer was the least toxic sealer amongst the chemicals tested in both cultures. The cytotoxic response decreased in an order of N2 > Endomethansone > AH26 > AHplus > Canals > Sealapex. Conclusions The sensitivity of toxicity depended on the materials tested and the cell culture system used. Thus, the use of both permanent and primary cells is recommended for screening of the cytotoxic effects of root canal sealers. In addition, the results confirmed that root canal sealers constantly dissolve when exposed to an aqueous environment for extended periods, possibly causing moderate or severe cytotoxic reactions. Use of calcium hydroxide-based material as a root canal sealer initially may result in a more favourable response to periradicular tissues.

Dynamic torque and apical forces of ProFile.04 rotary instruments during preparation of curved canals.

Abstract: Aim: To analyse torque and force generated whilst shaping curved canals using rotary instruments. Methodology: A specially designed computer-controlled testing platform was used to record events during the shaping of straight and curved canals in plastic blocks and in extracted human teeth using ProFile .04 instruments. Size 40 apical stops were prepared using crown-down, apical preparation and step-back procedures. Maximum torque, apically directed force and the numbers of revolutions were recorded at a resolution of 100 samples s. Load causing separation as required by the ISO 3630-1 test and cyclic fatigue was also recorded. Mean maximum scores were calculated and statistically tested using one- and two-way analyses of variance. Results: Highest and lowest torque scores were recorded, respectively, in straight canals in plastic blocks at 25 Nmm and in natural canals at 14 Nmm. Significant differences were recorded for canal type and preparation phase (P < 0.0001). Loads causing separation varied from 3.7 to 32.3 Nmm. Apically directed forces ranged from 1 to 7.5 N. Again, there were significant differences depending on canal type and preparation phase (P < 0.0001). The number of revolutions during preparation ranged from 18 to 41. Size 15, 30 and 45 ProFile .04 instruments separated after 581, 430 and 402 revolutions, respectively, in a standard cyclic fatigue test. Conclusions: The new torque-testing platform details physical parameters during preparation of curved canals. To improve predictability, instrumentation sequences must be tested for excessively high torsional moments or forces. This study indicated that up to 10 curved canals could be safely prepared with a sequence of ProFile. 04 rotary instruments without separation due to cyclic fatigue. Efforts should continue to correlate root canal anatomy with torque and force generated during rotary root canal preparation.

Endodontic implications of the maxillary sinus: a review

Abstract: The anatomical and clinical significance of the maxillary sinus in relation to conventional and surgical endodontic therapy is considered The discussion includes a review on the development, anatomy and physiology of the maxillary sinus, the diagnostic evaluation of the sinus and the differential diagnosis of sinusitis Endodontic implications of the maxillary sinus include extension of periapical infections into the sinus, the introduction of endodontic instruments and materials beyond the apices of teeth in close proximity to the sinus and the risks and complications associated with endodontic surgery

Influence of calcium hydroxide intracanal medication on apical seal.

Abstract: Aim The aim of this study was to determine the influence of calcium hydroxide intracanal medication and various techniques for its removal on the sealing ability of gutta-percha root fillings with a zinc oxide-eugenol sealer. Methodology Eighty extracted mature human mandibular molar roots were divided into three groups of similar root-canal configuration. Calcium hydroxide paste was made by mixing calcium hydroxide powder with distilled water at a powder to liquid ratio of 1:1.25. After root canals were prepared and enlarged to a minimum of size 30 with the Profile 0.06 system, calcium hydroxide paste was placed in the canals of two groups, but no medication was placed in the control group. The intracanal calcium hydroxide was removed with two different techniques, 1 week after medication: K-files one size larger than the master apical file (MAF) were used with 2.5% NaOCl and 15% EDTA solutions in one group, whilst K-files the same size as the MAF were used with 2.5% NaOCl solution in another group. Canals were obturated with gutta-percha and Tubli-Seal cement using the lateral condensation technique. The apical sealing-ability was assessed by dye leakage and cross-sections of the specimens were examined under a stereomicroscope. The dye-penetration level was measured and analyzed using Fisher's exact test and Duncan's multiple range test. Results The calcium hydroxide-medicated groups showed significantly more dye leakage than the non-medicated control group (P 0.05). The stereomicroscopic views showed a relatively uneven and thicker layer of sealer in the calcium hydroxide-medicated groups. Conclusion Calcium hydroxide intracanal medication may increase apical leakage of gutta-percha root fillings when a zinc oxide-eugenol sealer is used.

Shaping ability of Profile rotary nickel‐titanium instruments with ISO sized tips in simulated root canals: Part 1

Abstract: The aim of this study was to determine the shaping ability of ProFile 0.04 taper rotary nickel-titanium instruments with ISO sized tips in simulated canals. A total of 40 simulated root canal made up of four different shapes in terms of angle and position of curvature were prepared by ProFile instruments using the 'crown down' approach recommended by the manufacturer. Part 1 of this two-part report describes the efficacy of the instruments in terms of preparation time, instrument failure, canal blockages, loss of canal length and three-dimensional canal form. The time necessary for canal preparation was on average 5.2 min and was not influenced significantly by canal shape. Three instrument fractures occurred and a further 3 instruments deformed; size 35 instruments failed the most (4) followed by size 30 (2), four of the failures occurred in canals with 40 degrees curves. None of the canals became blocked with debris and change in working distance was minimal. Intra-canal impressions of canal form demonstrated that most canals had apical stops and smooth canal walls whereas all canals had good flow and taper. Under the conditions of this study, ProFile 0.04 taper rotary nickel-titanium instruments with ISO sized tips prepared simulated canals rapidly and created good three-dimensional form.

Periapical status, prevalence and quality of endodontic treatment in an adult French population.

Abstract: Lupi-Pegurier L, Bertrand M-F, Muller-Bolla M, Rocca JP, Bolla M. Periapical status, prevalence and quality of endodontic treatment in an adult French population. International Endodontic Journal, 35, 690^697, 2002. Aim The aim of this study was to determine the periapical status and the quality of root-canal treatment amongst an adult population attending the dental school in Nice, France during 1998. Methodology Patients who attended the dental school for the ¢rst time during 1998 were included. Panoramic radiographs, taken by a trained radiology assistant, were used in this study. The periapical areas of all teeth with the exception of third molars, were examined and the technical quality of root ¢llings were evaluated for both apical extension and density. Statistical analyses were conducted using anova, Chi-square, Fisher’s PLSD and Cohen’s Kappa tests. Results The survey involved 344 patients: 180 females and 164 males. Males had signi¢cantly fewer natural remaining teeth than females (P < 0.03). Similarly, the average number of root-¢lled teeth was lower for males (P < 0.01). Nonroot-¢lled teeth (n ¼ 6126) had signi¢cantly fewer signs of periapical pathology than root-¢lled teeth (n ¼ 1429) (1.7% vs. 31.5%, P < 0.0001). The majority of root ¢llings were poorly executed. There was a signi¢cant correlation between the presence of periapical pathology and inadequate root-canal ¢llings (P < 0.001). Conclusions The results of the present study indicate that many root-canal treatments were technically unsatisfactory in terms of quality and treatment outcome. There is a need for endodontic retreatment in the population examined.

Prevalence of apical periodontitis and results of endodontic treatment in an adult, Portuguese population

Abstract: The present epidemiological study is derived from a random sample of 322 residents of the Porto area, aged 30-39 years. Prevalence of apical periodontitis and results of endodontic treatment were evaluated from orthopantomograms, available from 179 of a total of 197 individuals attending for examination. The results indicated a prevalence of apical periodontitis in 27% of this population. The quality of a majority (54%) of the 69 root fillings observed were found to be inadequate, (i.e. short and/or poorly condensed), but only 15 (22%) of the endodontically treated teeth presented with apical periodontitis.

A comparative study of root canal preparation using ProFile .04 and Lightspeed rotary Ni–Ti instruments

Abstract: Aim The purpose of this study was to compare several parameters of root canal preparation using two different rotary nickel–titanium instruments: ProFile .04 (Dentsply/Maillefer, Ballaigues, Switzerland) and Lightspeed (Lightspeed Technology Inc., San Antonio, TX, USA). Methodology Fifty extracted mandibular molars with root canal curvatures between 20° and 40° were divided into two similar groups having equal mean curvatures. The teeth were then embedded into a muffle system as described by Bramante et al. (1987) and modified by Hulsmann et al. (1999b). All root canals were prepared using ProFile .04 or Lightspeed Ni–Ti instruments to size 45 following the manufacturers’ instructions. The Lightspeed system was used in a step-back technique; ProFile .04 instruments were used in a crown-down technique. The following parameters were evaluated: straightening of curved root canals (superimposition of pre- and postoperative radiographs), postoperative root canal diameter (superimposition of pre- and postoperative photographs of root canal cross-sections), safety issues (file fractures, perforations, apical blockages, loss of working length) (protocol), cleaning ability (SEM-evaluation of root canal walls using a five-score system for debris and smear layer), and working time (protocol). Statistical analysis was performed using the Wilcoxon test (P < 0.05) for straightening, and Fisher’s exact-test (P < 0.05) for comparison of cross-sections, for comparison of contact between pre- and postoperative diameter, root canal cleanliness and working time. Results Both Ni–Ti systems maintained curvature well; the mean degree of straightening was less than 1° for both ProFile .04 and for Lightspeed with no statistical significance between the groups. Most procedural incidents occurred with Profile .04 instruments (three fractures), Lightspeed preparation was completed without instrument fractures. Loss of working length, perforations or apical blockage did not occur with either instrument. Following preparation with Profile .04, 64.0% of the root canals had a round, 30.7% an oval, and 5.3% an irregular cross-section, Lightspeed preparation resulted in a round cross-section in 41.3% of cases, an oval shape in 45.3% of cases; 13.3% of cases had an irregular cross-section. No significant differences were found between the two systems. Lightspeed instruments enlarged the root canal more uniformly with no specimen showing 50% or more contact between pre- and postoperative diameter. The difference was statistically significant only for the coronal third of the root canals (P = 0.032). Mean working time was significantly shorter for Profile .04 (105 s) than for Lightspeed (140 s) (P = 0.026). For debris removal Lightspeed achieved the best results (68% scores 1 and 2), followed by Profile .04 (48.4%) with no significant differences between the systems. The results for remaining smear layer were similar: the lowest amount of smear layer on the root canal walls was found after preparation with Lightspeed (30.7% scores 1 and 2), followed by Profile .04 (23.1%). In the coronal third of the root canals Lightspeed performed significantly better than Profile .04 (P = 0.029); in the middle and apical third the differences were not significant. Conclusions Both systems under investigation respected original root canal curvature and were safe to use. Both systems can be recommended for clinical use.

Evaluation of smear layer removal by EDTAC and sodium hypochlorite with ultrasonic agitation

Abstract: Aim To evaluate smear layer removal by different irrigating solutions under ultrasonic agitation. Methodology Twenty recently extracted mandibular incisors with a single root canal were divided into four equal groups. Three groups were instrumented using the modified double-flared technique, the fourth remained unprepared. Each group was irrigated with either distilled water, 1.0% sodium hypochlorite alone or associated with 15% EDTAC between each file size. The final group was not instrumented but irrigated with 1.0% sodium hypochlorite and 15% EDTAC. A size 15 file energised by ultrasound was used with small amplitude filing movements against the canal walls in all groups. The teeth were split longitudinally and the roots measured to provide three sections of the same size (cervical, middle and apical). Samples were examined under the scanning electron microscope and assessed for the amount of smear layer by three independent and calibrated examiners. The scoring system ranged from 1 (no smear layer) to 4 (all areas covered by smear layer). Due to the non-parametric nature of the data, Friedman’s test was used for statistical analysis. Results Canal walls were covered with smear layer in the group irrigated with 1% sodium hypochlorite alone and the group irrigated with distilled water. Canals irrigated with 1.0% sodium hypochlorite associated with 15% EDTAC had less smear layer throughout the canal (P < 0.001). There were no statistical differences for the amount of smear layer found on the cervical, middle and apical thirds when each group was analysed separately. Conclusions Under ultrasonic agitation, sodium hypochlorite associated with EDTAC removed the smear layer from root canal walls, whereas irrigation with distilled water or 1.0% sodium hypochlorite alone did not remove smear layer.

A survey of endodontic practice amongst Flemish dentists.

Abstract: AIM The purpose of this study was to gather information on routine endodontic treatment performed by Flemish (Dutch-speaking Belgian) dentists. METHODOLOGY A postal questionnaire was sent to all the 4545 Dutch-speaking dentists registered in Belgium. The questionnaire was made up of 38 questions with multiple-choice answers. Results from 32 questions are presented, covering subjects, such as demographic and professional activity, root-canal preparation and instrumentation, emergency procedures and postoperative complications, choice of irrigants and disinfectants, and choice of obturation techniques. RESULTS A total of 1143 questionnaires (25.1%) were returned. Approximately 94% of the respondents were general practitioners. The results indicate that there are discrepancies between daily practice and academic teaching, especially regarding the use of rubber dam (only 3.4% report using it as a standard procedure) and the detection and preparation of a second mesiobuccal canal in maxillary first molars (70% never or seldom). Most GDPs reported that they completed treatment in two visits. The majority of practitioners used manual instruments manipulated with a filing technique; 38.9% of the respondents prepared root canals 1 mm short of the radiographic apex. The most popular emergency procedure for acute pain was pulpectomy (40.2%); 48% performed pulpectomy, prescribed analgesics and antibiotics for acute apical periodontitis. Approximately 35% reported complications after cases with chronic apical periodontitis were treated. The first-choice root-canal irrigant was sodium hypochlorite and approximately 65% used intracanal medication. The most popular obturation technique was cold lateral condensation (60%) with 29% using AH26 as a sealer. A high proportion of GDPs (80%) performed re-treatments. CONCLUSIONS The results of this study confirm that many Flemish general practitioners are not following quality guidelines for endodontic treatment.

The effects of dentine pretreatment on the adhesion of root‐canal sealers

Abstract: Aim The adhesion of five root-canal sealers to dentine and gutta-percha was studied. The effects of various dentine pretreatments on adhesion were also investigated. Methodology Root dentine cylinders, 4 mm in diameter, were prepared from human teeth. The dentine surfaces were conditioned with either 37% H(3)PO(4) for 30 s, 25% citric acid for 30 s, 17% EDTA for 5 min or a rinse with 10 mL distilled water (control). Gutta-percha cylinders, 4 mm in diameter, were prepared and their end surfaces polished flat. The dentine and gutta-percha surfaces were coated with freshly mixed sealer: Grossman's sealer (GS), Apexit (AP), Ketac-Endo (KE), AH Plus (AH), RoekoSeal Automix (RS) or RoekoSeal Automix with an experimental primer (RP). The surfaces were pressed together and the sealers allowed to set. The test specimens were subjected to a tensile force in a universal testing machine. Results Mean tensile bond strengths (MPa +/- SD) ranged from 0.07 +/- 0.01 (AP) to 1.19 +/- 0.47 (AH). Pretreatment with EDTA showed no effect or produced weaker bonds than controls. Phosphoric and citric acid pretreatments increased adhesion of GS. A primer used with RoekoSeal significantly enhanced its adhesion to untreated dentine. Inspection of fractured surfaces indicated failure of adhesion to dentine for GS and RS and to gutta-percha for KE and RP. The failure appeared to be mainly cohesive within the sealer for AH and AP. Conclusions Removal of the smear layer may impair sealer adhesion to dentine. Different sealer types require different dentine pretreatments for optimal adhesion.

Accuracy of a new apex locator: an in vitro study

Abstract: Kaufman AY, Keila S, Yoshpe M. Accuracy of a new apex locator: an in vitro study. International Endodontic Journal , 35 , 186‐192, 2002. Aim The purpose of this study was to test in an in vitro model the accuracy of a Bingo 1020 electronic apex locator, to compare the results to those of a well known apex locator, Root ZX, as well as to those of the radiographic method of tooth length determination. Methodology A total of 120 extracted teeth, preserved in Thymol solution and kept refrigerated, was used for the study. The experiment was performed on singlerooted teeth and on one-root canal, chosen randomly, in multirooted teeth. The teeth were randomly divided into 12 groups of 10 teeth each. After access preparation, the actual length (AL) was measured. The teeth were embedded in an alginate model specially developed for testing apex locators. Electronic tooth length measurements (EL) were carried out prior to root canal preparation using the two electronic apex locators (EAL) ‐ Root ZX and Bingo 1020; three measurements were taken and an average computed. After the third measurement, the file was left in the root canal and a periapical radiograph was taken. The radiographic length (RL) was recorded by measuring the file length from the coronal reference point to the tip of the file. Each root canal was then prepared to a no. 40 K-file diameter using a standardized technique; saline was used for irrigation. Upon completion of the root canal preparation, EL measurements were taken by each EAL in dry conditions and with different irrigation solutions. Each measurement was repeated three times. The RL was recorded according to the last EL measurement. Results were subjected to statistical analysis. Results In all parameters tested, a significant statistical difference was found between Bingo 1020 and the Root ZX. Measurements obtained using the Bingo 1020 were consistently closer to the AL (0.08 mm) than those obtained using the Root ZX. Both EALs measured the tooth length with great accuracy and a positive correlation of 0.76 ( P = 0.00) existed between the two devices. No significant difference was found between the two apex locators when measurements were taken with the different irrigants ( P = 0.34) and the content of the root canal did not affect the accuracy of the measurements. Lengths obtained by calculations from the radiographs were longer than the AL as well as the length obtained by both EALs ( P = 0.00). Conclusions The Bingo 1020 proved to be as reliable as Root ZX and was user friendly. Under the experimental conditions, electronic measurements were more reliable than radiographs in the process of root length determination.

An in vitro comparison of the bactericidal efficacy of lethal photosensitization or sodium hyphochlorite irrigation on Streptococcus intermedius biofilms in root canals.

Abstract: Aim To compare the bacterial killing of Streptococcus intermedius biofilms in root canals using lethal photosensitization with various combinations of photosensitizer concentration and laser light dose or 3% sodium hypochlorite (NaOCl) irrigation.Methodology Extracted teeth (n = 3 5) with single canals were selected and the canals prepared to apical size 2 5 with a 10% taper. The teeth were autoclaved and the canals inoculated with Streptococcus intermedius in brain heart infusion broth and were incubated for 48 h to allow a biofilm to form. The teeth were then subjected to 3% NaOCl irrigation (n = 4) or lethal photosensitization using combinations of a range of toluidine blue O (TBO) photosensitizer concentrations (12.5, 25, 50, 100 mugmL(-1)) and light doses (60, 90, 120, 300, 600 s equivalent to energy doses of 2.1-21 J) using a 35-mW helium-neon low power laser targeted at the access cavity (n = 4 for each combination). Controls consisted of laser light only (TBO = O mugmL(-1)) (n = 4), TBO only (light dose 0 s) (n = 4), and no treatment (positive control It 17). Following treatment the canal contents were sampled with sterile paper points, the sample was dispersed in transport medium. serially diluted and cultured on blood agar to determine the number of colony forming units (CFU).Results The combination of 100 mugmL(-1) TBO and 600 s (211) of laser energy achieved maximum reduction in recovered viable bacteria (5 log(10) CFU). TBO at low concentrations (less than or equal to50 mugmL(-1)) was not bactericidal but treatment with 100 mugmL(-1) TBO alone reduced recovered viable bacteria by 3 log,() CFU. Laser light alone had limited bactericidal effect. No viable bacteria were recovered following treatment with 3% NaOCl.Conclusions The combined use of a photosensitizing agent and a low power laser directed at the access cavity was bactericidal to S. intermedius biofilms in root canals but was unable to achieve total kill, unlike 3% NaOCl.

Influence of irrigants on the coronal microleakage of laterally condensed gutta-percha root fillings

Abstract: Vivacqua-Gomes N, Ferraz CCR, Gomes BPFA, Zaia AA, Teixeira FB, Souza-Filho FJ. Influence of irrigants on the coronal microleakage of laterally condensed gutta-percha root fill- ings. International Endodontic Journal, 35, 791^795, 2002. Aim To assess in vitro coronal microleakage in extracted human teeth after root-canal treatment, using diierent endodontic irrigants. Methodology Fifty teeth with single root canals were prepared and ¢lled using the lateral condensa- tion of gutta-percha and Endomethasone sealer. Canal preparation consisted of initial shaping of the coronal two-thirds with Gates-Glidden burs size 2 and 3, fol- lowed by preparation of the apical stop and step-back £aring with manual ¢les. Each group (n ¼ 10) was irri- gated with the following solutions: I ^ 1% NaOCl, II ^ 1% NaOCl þ 17% EDTA, III ^ 2% chlorhexidine gel, IV ^ 2% chlorhexidine gel þ 1% NaOCl, and V ^ dis- tilled water. After root-canal ¢lling, the teeth were incubated at 37 8C for 10 days followed by 10 days immersion in human saliva and an additional 10 days in India ink. The teeth were cleared and maximum dye penetration was determined digitally in milli- metres. Statistical analysis was carried out using the Kruskal^Wallis test. Results Least leakage occurred with 1% NaOCl þ 17% EDTA (2.62 mm) and 2% chlorhexidine gel (2.78 mm) (P > 0.05). NaOCl (3.51 mm), distilled water (6.10 mm) and 2% chlorhexidine gel þ 1% NaOCl (9.36 mm) gave increased leakage with a signif- icant diierence compared to NaOCl þ 17% EDTA and 2% chlorhexidine gel, and compared to one another (P < 0.05). Conclusions Under the condition of this study, irri- gation method during root-canal treatment in£uenced coronal microleakage. NaOCl þ EDTA and chlorhexi- dine gel allowed better sealing following root ¢lling.

Effects of rotary instruments and ultrasonic irrigation on debris and smear layer scores: a scanning electron microscopic study

Abstract: Aim: This study evaluated debris and smear layer scores after two types of instruments manufactured from different alloys were used to ultrasonically activate irrigants during canal preparation. The influence of two rotary preparation techniques on cleanliness of the shaped canals was also studied. Methodology: Apical stops were prepared to size 45 in 42 single-canalled extracted premolars and canines, which were divided into six equal groups. Groups 1, 2 and 3 were prepared by ProFile .04 (PF) while groups 4, 5 and 6 were prepared by Lightspeed (LS). All groups were irrigated using 5.25% NaOCl and 17% EDTA. Irrigants in groups 2 and 5 were ultrasonically activated using a size 15 steel K-file and by a blunt flexible nickel-titanium wire in groups 3 and 6. Groups 1 and 4 served as negative controls. Roots were split and canal walls examined at 15x, 200x and 400x magnification in an SEM. Smear layer and debris scores were recorded at 3, 6 and 9 mm levels using a 5-step scoring scale and a 200-μm grid. Means were tested for significance using nonparametric Mann-Whitney U and Kruskal-Wallis tests. Results: Debris and smear layer scores for the six groups varied from 1.98 ± 1.04 to 3.47 ± 0.97 and from 1.37 ± 0.4 to 2.36 ± 0.99, respectively. Although all groups had significantly higher smear layer and debris scores at the 3 mm levels compared to the 9 mm levels (P < 0.05), no significant differences were recorded due to the ultrasonic energy transmitted by the two alloys. Conclusion: Ultrasonically activated irrigants did not reduce debris or smear layer scores. This finding was not influenced by the material nor by the design of the instrument used to transmit ultrasonic activation.

Reduction in intracanal bacteria during root canal preparation with and without apical enlargement

Abstract: Coldero LG, McHugh S, MacKenzie D, Saunders WP. Reduction in intracanal bacteria during root canal preparation with and without apical enlargement. International Endodontic Journal, 35, 437‐446, 2002. Aim To compare in vitro intracanal bacterial reduction using nickel‐titanium rotary instruments with and without apical enlargement. Methodology Thirty-eight palatal roots of maxillary molar teeth, with mature apices were subdivided according to lengths and then randomly assigned to two experimental and one control groups. The roots were sterilized and then reinfected with Enterococcus faecalis, which served as a bacteriological marker. All roots in the experimental groups were prepared in a step-down sequence with engine-driven GT rotary files at 350 rpm. In experimental group A (n = 16) additional apical enlargement to ISO size 35 was performed. In group B (n = 16) a serial step-back technique was followed with no apical enlargement. This was combined in groups A and B with irrigation with NaOCl and EDTA. In the control group (group C, n = 6) irrigation only was carried out, with no mechanical preparation. Samples were then taken from the root canals to determine the numbers of remaining bacteria. Results In groups A and B, 15 (94%) and 13 (81%) specimens were rendered bacteria-free, respectively. In the control group C none of the specimens were bacteriafree. There was a significant difference (P < 0.001) in the antibacterial effects of experimental and control regimens. There was, however, no significant difference (P = 0.276) between the preparation methods used in the experimental groups. Conclusions There was no significant difference in intracanal bacterial reduction when Ni‐Ti GT rotary preparation with NaOCl and EDTA irrigation was used with or without apical enlargement preparation technique. It may therefore not be necessary to remove dentine in the apical part of the root canal when a suitable coronal taper is achieved to allow satisfactory irrigation of the root canal system with antimicrobial agents.

Efficiency of rotary nickel-titanium FlexMaster instruments compared with stainless steel hand K-Flexofile--Part 2. Cleaning effectiveness and instrumentation results in severely curved root canals of extracted teeth.

Abstract: Aim To determine the cleaning effectiveness and the shaping ability of FlexMaster nickel-titanium rotary instruments and stainless steel hand K-Flexofiles during the preparation of curved root canals in extracted human teeth. Methodology A total of 48 root canals with curvatures ranging between 25 degrees and 35 degrees were divided into two groups of 24 canals. Based on radiographs taken prior to the instrumentation with the initial instrument inserted into the canal, the groups were balanced with respect to the angle and the radius of canal curvature. Canals were prepared by FlexMaster instruments using a crown-down preparation technique or by K-Flexofiles using a reaming working motion up to size 35. After each instrument, the root canals were flushed with 5 mL of a 2.5% NaOCl solution and at the end of instrumentation with 5 mL of NaCl. Using the pre- and post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. After splitting the roots longitudinally, the amount of debris and smear layer were quantified on the basis of a numerical evaluation scale, using a scanning electron microscope. Results Completely cleaned root canals were not found with any of the two instruments. In general, K-Flexofiles resulted in significantly less debris(P 0.05). FlexMaster instruments maintained the original canal curvature significantly better (P 0.05) for the time taken to prepare the canals. Conclusions Under the conditions of this study, K-Flexofiles allowed significantly better canal cleaning than FlexMaster instruments. FlexMaster instruments maintained the original curvature significantly better.