Showing papers in "International Endodontic Journal in 2008"

Canal preparation using only one Ni-Ti rotary instrument: preliminary observations

Abstract: Yared G. Canal preparation using only one Ni-Ti rotary instrument: preliminary observations. International Endodontic Journal. Aim To describe a novel canal preparation technique using only one Ni-Ti rotary instrument. Summary In this novel technique, the canal is negotiated to the working length with a size 08 hand file. Then, the canal preparation is completed with an F2 ProTaper instrument used in a reciprocating movement. In larger canals, the use of additional hand files may be required to complete the apical enlargement. Key learning points • A novel canal preparation technique is introduced using only one Ni-Ti rotary instrument in a reciprocating movement. • The advantages of the technique include a reduced number of instruments, lower cost, a reduced instrument fatigue and the elimination of possible prion cross-contamination associated with the single use of endodontic instruments.

Characterization of hydration products of mineral trioxide aggregate.

Abstract: Objective To characterize the hydration products of white mineral trioxide aggregate (MTA). Methodology Mineral trioxide aggregate, white Portland cement and bismuth oxide were evaluated using X-ray diffraction (XRD) analysis and Rietveld XRD. The cements were tested un-hydrated and after hydration and curing for 30 days at 37 °C. Analysis of hydrated cement leachate was performed weekly for five consecutive weeks from mixing using inductively coupled plasma atomic emission spectroscopy after which the cements were viewed under the scanning electron microscope to evaluate the cement microstructure. Quantitative energy dispersive analysis with X-ray was performed and atomic ratios were plotted. Results Both Portland cement and MTA produced calcium silicate hydrate (C-S-H) and calcium hydroxide (CH) on hydration. The tricalcium aluminate levels were low for MTA which resulted in reduced production of ettringite and monosulphate. On hydration the bismuth level in the hydrated MTA decreased; bismuth oxide replaced the silica in the C-S-H and was leached out once the C-S-H decomposed with time. Both MTA and Portland cement released a high amount of calcium ions which decreased in amount over the 5-week period. Conclusions The hydration mechanism of MTA is different to that of Portland cement. In MTA the bismuth oxide is bound to the C-S-H and is leached out from the cement with time as the C-S-H decomposes. MTA produces a high proportion of calcium ions from CH a by-product of hydration and also by decomposition of C-S-H. The release of calcium ions reduces with time.

Dens invaginatus. Part 1: classification, prevalence and aetiology.

Abstract: Aim To review and discuss the aetiology, prevalence and classification of this dental anomaly together with the morphology of an invagination and the most appropriate nomenclature. Summary This review considers the different possible nomenclatures and concludes that dens invaginatus is the most appropriate description. The paper highlights the different reported prevalence figures and concludes that the problem is probably one of the most common of the dental developmental abnormalities with maxillary lateral incisors most commonly affected. The paper suggests that the classification system described by Oehlers (1957a) is probably the most clinically relevant and that the morphological features associated with this problem may increase the risk of pulpal pathology developing and complicate any possible endodontic treatment. Key learning points • The aetiology of dens invaginatus is still unknown, although there is some evidence that it may be genetic in origin. • The problem is probably more prevalent than most clinicians are aware of and this is because of the diagnostic difficulties associated with the anomaly. • The nature of the problem may increase the risk of pulp disease and complicate any root canal treatment.

Efficacy of ProTaper Universal rotary retreatment system for gutta-percha removal from root canals

Abstract: Aim To evaluate the efficacy of the ProTaper Universal rotary retreatment system for gutta-percha (GP) removal from root canals. Methodology Root canals of 60 extracted human maxillary anterior teeth were prepared and filled with laterally condensed GP and AH Plus sealer. Teeth were divided into three groups: group A – GP removal completed with the ProTaper Universal rotary retreatment system and with further canal repreparation accomplished with ProTaper Universal rotary instruments; group B – GP removal was completed using Gates Glidden drills and Hedstrom files with chloroform as a solvent, followed with further canal repreparation with ProTaper Universal rotary instruments; group C – the same as group B for GP removal with further canal preparation with stainless steel K-flex files (Kerr). The operating time was recorded. Teeth were rendered transparent for the evaluation of the area of remaining GP/sealer in bucco-lingual and mesial–distal directions. Statistical analysis was performed by using repeated measures analysis of variance and anova. Results The ProTaper Universal technique (group A) resulted in a smaller percentage of canal area covered by residual GP/sealer than in groups B and C, with a significant difference between groups A and C (P < 0.05). Mean operating time for group A was 6.73 min, which was significantly shorter (P < 0.05) than group B (10.86 min) and group C (13.52 min). Conclusions In this laboratory study all test techniques left GP/sealer remnants within the root canal. The ProTaper Universal rotary retreatment system proved to be an efficient method of removing GP and sealer from maxillary anterior teeth.

Efficacy of three rotary NiTi instruments in removing gutta‐percha from root canals

Abstract: Aim To investigate the ability of three rotary nickel–titanium instruments and hand instrumentation to remove gutta-percha and sealer. Methodology Sixty freshly extracted human single-rooted teeth, each with one root canal, were instrumented with K-files and filled using cold lateral compaction of gutta-percha and AH Plus (Dentsply Detrey, Konstanz, Germany) sealer. The teeth were randomly divided into four groups of 15 specimens each. Removal of gutta-percha was performed with the following devices and techniques: ProTaper, R-Endo, Mtwo and Hedstrom files. The specimens were rendered transparent and the area of remaining filling material on the root canal wall was measured using a computer image analysis program. Statistical analysis was accomplished by Kruskal–Wallis and Mann–Whitney U-tests with Bonferroni correction for the analysis of residual root filling material and working time. Results The ProTaper group had less filling material inside the root canals than the other groups, but a significant difference was found between only the ProTaper and Mtwo groups (P < 0.05). The retreatment time for Mtwo and ProTaper was significantly shorter compared with R-Endo and manual instrumentation with Hedstrom files (P < 0.001). R-Endo was significantly faster than manual instrumentation (P < 0.001). Conclusions Under the experimental conditions, ProTaper left significantly less gutta-percha and sealer than Mtwo instruments. Complete removal of materials did not occur with any of the instrument systems investigated.

Pulp stones: a review.

Abstract: Pulp stones are a frequent finding on bitewing and periapical radiographs but receive relatively little attention in textbooks. A review of the literature was therefore performed, initially using the PubMed database and beginning the search with 'pulp calcifications' and 'pulp stones'. Each term provided more than 400 references, many of which related to pulp calcification in general rather than pulp stones, and focussed largely on the problems these changes presented to clinicians. A manual search using references from this source was carried out. Contemporary textbooks in endodontology were also consulted, and an historic perspective gained from a number of older books and references. The factors involved in the development of the pulp stones are largely unknown. Further research may determine the reasons for their formation, but with current endodontic instruments and techniques this is unlikely to alter their relevance to clinicians.

Taurodontism: a review of the condition and endodontic treatment challenges

Abstract: Taurodontism can be defined as a change in tooth shape caused by the failure of Hertwig's epithelial sheath diaphragm to invaginate at the proper horizontal level. An enlarged pulp chamber, apical displacement of the pulpal floor, and no constriction at the level of the cementoenamel junction are the characteristic features. Although permanent molar teeth are most commonly affected, this change can also be seen in both the permanent and deciduous dentition, unilaterally or bilaterally, and in any combination of teeth or quadrants. Whilst it appears most frequently as an isolated anomaly, its association with several syndromes and abnormalities has also been reported. The literature on taurodontism in the context of endodontics up to March 2007 was reviewed using PubMed, MEDLINE and Cumulative Index to Nursing & Allied Health Literature. Despite the clinical challenges in endodontic therapy, taurodontism has received little attention from clinicians. In performing root canal treatment on such teeth, one should appreciate the complexity of the root canal system, canal obliteration and configuration, and the potential for additional root canal systems. Careful exploration of the grooves between all orifices particularly with magnification, use of ultrasonic irrigation; and a modified filling technique are of particular use.

Long-term sealing ability of Pulp Canal Sealer, AH-Plus, GuttaFlow and Epiphany

Abstract: AIM: To evaluate the long-term sealing ability of four contemporary endodontic sealers [Pulp Canal Sealer (PCS), AH-Plus, GuttaFlow and Epiphany] using a fluid filtration technique. METHODOLOGY: The palatal roots of 40 human maxillary molar teeth were selected and the root canal was prepared using a crown-down technique (apical size 40, 6% taper). Roots were irrigated with 3% NaOCl, 17% EDTA solution and rinsed with distilled water. Canals were filled with either PCS, AH-Plus, GuttaFlow or Epiphany using a single-cone technique (n = 8). Twenty-four hours after filling, the roots were connected to an automatic flow-recording device (Flodec System) filled with double-distilled water under pressure (0.2 bar) to measure leakage. Flow rates were assessed at 6, 12 or 24-h and after 1-year of storage. RESULTS: None of the materials fully prevented fluid flow. Fluid flow decreased after 6 h and decreased further after 12 h. After 24 h, PCS and AH-Plus allowed significantly more fluid flow than GuttaFlow and Epiphany. After 1 year, PCS allowed significantly more fluid flow than the other materials. No significant changes in leakage occurred between 24 h and 1 year. CONCLUSIONS: GuttaFlow and Epiphany allowed less fluid movement along filled straight roots.

The effectiveness of mineral trioxide aggregate, calcium hydroxide and formocresol for pulpotomies in primary teeth

Abstract: Aim To compare the effectiveness of mineral trioxide aggregate (MTA), calcium hydroxide (CH) and formocresol (FC) as pulp dressing agents in carious primary teeth. Methodology Forty-five primary mandibular molars with dental caries in 23 children [AUTHOR QUERY: How many children?] between 5 and 9 years old were treated by a conventional pulpotomy technique. The teeth were randomly assigned to the experimental (CH or MTA) or control (FC) groups. After coronal pulp removal and haemostasis, remaining pulp tissue was covered with MTA paste or CH powder in the experimental groups. In the control group, diluted FC was placed with a cotton pellet over the pulp tissue for 5 min and removed; the pulp tissue was then covered with zinc oxide–eugenol (ZOE) paste. All teeth were restored with reinforced ZOE base and resin modified glass–ionomer cement. Clinical and radiographic successes and failures were recorded at 3, 6, 12, 18 and 24 month follow-up. Results Forty-three teeth were available for follow-up. In the FC and MTA groups, 100% of the available teeth were clinically and radiographically successful at all follow-up appointments; dentine bridge formation could be detected in 29% of the teeth treated with MTA. In the CH group, 64% of the teeth presented clinical and radiographic failures detected throughout the follow-up period, and internal resorption was a frequent radiographic finding. Conclusions Mineral trioxide aggregate was superior to CH and equally as effective as FC as a pulpotomy dressing in primary mandibular molars. Internal resorption was the most common radiographic finding up to 24 month after pulpotomies performed with CH.

Treatment of inflammatory internal root resorption with mineral trioxide aggregate: a case report

Abstract: Jacobovitz M, de Lima RKP. Treatment of inflammatory internal root resorption with mineral trioxide aggregate: a case report. International Endodontic Journal, 41, 905‐912, 2008. Aim To report the treatment and follow-up of a maxillary central incisor with internal resorption managed by root canal treatment, white mineral trioxide aggregate (MTA) repair and a fibre-glass post for reinforcement. Summary This study presents a case of extensive internal root resorption affecting tooth 11 (FDI) in a 28-year-old male patient, with a history of trauma in that region. The substantial loss of tooth structure, including cementum, and a perforation with lateral periodontal communication were complicating factors. Despite a guarded prognosis but encouraged by a healthy periodontal condition, treatment based on reconstructing the tooth with white MTA and a fibre-glass core was carried out. Follow-up radiographs over 20 months demonstrated the maintenance of a functional tooth. The tooth did, however, discolour after MTA treatment. Key learning points • Because of its insidious pathology, internal root resorption can extend to significant dimensions before being recognized. • MTA plus the fitting of a fibre-glass post provided adequate, functional rehabilitation of a compromised tooth for 20 months. • Despite the favourable biological and mechanical properties of white MTA, considerable tooth discolouration may occur.

The efficacy of dynamic irrigation using a commercially available system (RinsEndo®) determined by removal of a collagen ‘bio-molecular film’ from an ex vivo model

Abstract: Aim To compare the efficacy of three irrigation protocols using an established ex vivo bio-molecular film model.Methodology Thirty human teeth with single straight canals were randomly allocated to three groups [static, manual-dynamic, automated-dynamic (RinsEndo (R))]; each with a sub-group (n = 5) for needle position at 4 or 10 mm short of the working length (WL). The root canals were prepared to apical size 40, taper 0.08. The teeth were split longitudinally into two halves and a standard coat of stained-collagen was applied to the canal surfaces. The re-assembled teeth were irrigated using one of the protocols with the irrigation needle at one of two positions. Digital images of the canal surfaces, before and after irrigation with 18 mL of 2.5% NaOCl, were used to score surface coverage with stained-collagen using image-analyses (ipWin4 (R)). The data were analysed using linear regression models.Results The canal area covered with stained-collagen was significantly (P < 0.001) less after dynamic irrigation (manual/automated) compared with static irrigation; but automated-dynamic irrigation was significantly (P = 0.037) less effective than manual-dynamic irrigation. The 'orientation of needle port', 'corono-apical level of canal' and 'apical extent of needle placement' were significant (P < 0.001) factors influencing efficacy of irrigation. Residual collagen was most evident in the coronal third. Deeper penetration of the needle tip resulted in significantly (P < 0.001) more effective collagen removal.Conclusions Automated-dynamic irrigation was significantly more effective (16%) than static irrigation but significantly less effective (5%) than manual-dynamic irrigation. Irrigation was more effective (7%) when the needle was placed closer to WL.

Root and canal morphology of the mesiobuccal and distal roots of permanent first molars in a Kuwait population – a clinical study

Abstract: Aim To identify the number of roots and canal configurations in permanent first molars of the indigenous Kuwaiti sub-population and compare them against a similar group of non-Kuwaiti population in different age groups and gender, and to determine the frequency of a second canal in the mesiobuccal root of maxillary first molars and distal root of mandibular first molars that could be located and treated in routine practice without using magnification or special lighting conditions. Methodology A total of 220 permanent first molar teeth of patients scheduled for root canal treatment over a period of 1 year were included. Patients were identified and grouped according to their nationality as Kuwaiti and non-Kuwaiti (which included Filipinos, Indonesian Indians, Srilankans, Egyptians, Saudi Arabians and Syrians). In both nationality groups, patients were successively distributed into four groups based on their age. The first age group included patients below 20 years, the second 21–30 years, the third 31–40 years and the fourth were over 40 years. The first three groups comprised of 15 male and 15 female patients whilst the fourth group had 10 patients of each gender. Teeth with open apices, resorptions and calcification were excluded from the study. The teeth included were both clinically and radiographically examined for number of roots, the canal configuration and the presence of the additional mesiobuccal and distal canals and recorded. The simplified classification of canal configurations proposed by Weine was utilized. Results The incidence of a second canal in the mesiobuccal (MB) root of maxillary first molars and the distal root of mandibular first molars was not influenced significantly by nationality and gender. All the 110 maxillary first molars treated had three roots; 58% of MB root had one canal and 42% had two canals. The majority of the mesial roots had Weine type II canal configuration when the second mesiobuccal canal was present. All distobuccal and palatal roots had a single or type I canal configuration. Of the 110 mandibular first molars that were treated, 96% had two roots and 4% had three roots. When present, the third root was located either buccal or lingual to the main distal root. Overall 51% of the single distal roots had one canal whilst 49% had two canals. The mesial root frequently had a Weine type II canal configuration as did the distal root when a second canal was present. Pearson’s correlation analysis of both molars revealed a significant (P < 0.05) negative correlation (r = −0.274, r = −0.144) between age and number of canals as well as the type of canal. Conclusions The incidence of a second canal in distal roots of permanent mandibular first molars was 49% in the Kuwaiti population and this was similar to other Asian ethnic populations. Adopting modified access and troughing procedures revealed a 42% frequency of MB2 canals in maxillary first molars. The incidence of a second canal in both mesiobuccal roots of maxillary molars and distal roots of mandibular molars decreased significantly with age; no differences were noticed amongst the nationalities and gender studied. The possibility of extra roots should be anticipated in mandibular molars.

Clinical long-term evaluation of MTA as a direct pulp capping material in primary teeth.

Abstract: Aim To evaluate the effectiveness of mineral trioxide aggregate (MTA) when used as a pulp capping material in primary teeth. Methodology Clinical follow-up was performed on 25 symmetrical pairs of primary molars with deep occlusal caries, in 25 patients between the ages of 5 and 8 years. Pulps exposed during cavity preparation were treated by direct pulp capping with MTA or calcium hydroxide, based with resin-bonded zinc oxide eugenol cement and restored with amalgam. Clinical and radiographic examinations were carried out at 1, 3, 6, 9, 12, 18 and 24 months. Results Twenty-four-month clinical and radiographic follow-ups were carried out on 22 patients. One patient failed to return for evaluation after 1 month, one after 9 months and another after 12 months. During follow-up, none of the MTA and calcium hydroxide groups exhibited clinical or radiographic failure. Conclusions Mineral trioxide aggregate was found to be as successful as calcium hydroxide when used for direct pulp capping in primary teeth. Further histological investigations are needed to support these findings.

Do bioactive glasses convey a disinfecting mechanism beyond a mere increase in pH

Abstract: AIM: To test whether bioactive glasses kill microbiota via mineralization or the release of ions other than sodium. METHODOLOGY: Flame-spray synthesis was applied to produce nanometric glasses of different sodium content and constant Ca/P ratio: 28S5, 45S5 and 77S. Calcium hydroxide and nanometric tricalcium phosphate (TCP) were used as controls. Apatite induction was monitored by Raman spectroscopy. Bovine dentine disks with adherent Enterococcus faecalis cells were exposed to test and control suspensions or buffered solutions for 1 h, 1 day and 1 week. Colony-forming units were counted and disks were inspected using scanning electron microscopy. Suspension supernatants and solutions were analysed for their pH, osmolarity, calcium and silicon content. RESULTS: Sodium containing glasses induced pH levels above 12, compared with less than pH 9 with sodium-free 77S. Calcium hydroxide, 45S5 and 28S5 killed all bacteria after 1 day and lysed them after 1 week. TCP caused the highest apatite induction and substantial calcification on bacteria adhering to dentine, but did not reduce viable counts. 77S achieved disinfection after 1 week without visible apatite formation, whilst the buffer solution at pH 9 caused only minimal reduction in counts. CONCLUSION: Bioactive glasses have a directly and an indirectly pH-related antibacterial effect. The effect not directly linked to pH is because of ion release rather than mineralization.

Effect of photo-activated disinfection on endodontic pathogens ex vivo.

Abstract: Aim To test the hypothesis that photo-activated disinfection (PAD) has a bactericidal effect on pathogens inoculated in root canals, with emphasis on biofilm formation/destruction. Methodology Root canals of extracted teeth (n = 38) were prepared (size 30, 0.10 taper), autoclaved, divided into three groups and two negative controls inoculated (Streptococcus anginosus, Enterococcus faecalis or Fusobacterium nucleatum) and treated (PAD, laser, dye or positive control) according to a cross-sectional design. Resultant colony-forming unit counts were associated with observations of cell structural changes using environmental scanning electron microscopy (ESEM) on inoculated dentinal surfaces (n = 22, two controls) before (1, 2 and 6 days of incubation) and after treatment with PAD. Results Treatment of root canals with PAD (15 J) caused a significant reduction of the bacterial load, resulting in a 93.8% kill of S. anginosus (P < 0.0001), a 88.4% kill of E. faecalis (P < 0.05) and a 98.5% kill of F. nucleatum (P < 0.0001), but no sterilization. Laser alone had no significant effect on the load nor did the dye without laser. The ESEM experiment showed that individual cells or monolayers were easily eliminated with PAD. But when biofilms were present (2 and 6 days for E. faecalis, 6 days for S. anginosus), bacterial eradication was substantially reduced in deep layers. Conclusions Photo-activated disinfection is not an alternative but a possible supplement to the existing protocols for root canal disinfection as the interaction between light (diode laser) and associated dye (TBO) provides a broad-spectrum effect. Some endodontic pathogens that grow as single-species biofilms, however, are difficult to eradicate.

Dentinal tubule invasion and adherence by Enterococcus faecalis.

Abstract: Aim To investigate dentinal tubule invasion and the predilection of Enterococcus faecalis for dentinal tubule walls. Methodology The invasion of dentinal tubules in extracted human teeth by E. faecalis was measured ex vivo after 8 weeks of incubation. The canal walls of 16 root sections were either intact or instrumented with or without smear layer present. Extent and maximum depth of tubule invasion were assessed histologically and compared between groups. In the adherence study, 44 vertically split root samples were prepared to expose longitudinally aligned dentinal tubules and fractured orthodentine (OD). Surfaces were exposed to E. faecalis (erythromycin resistant strain, JH2-2 carrying plasmid pGh9:ISS1) and incubated aerobically for 2 h. Samples were processed for analysis using scanning electron microscopy. Bacterial adhesion to tubule walls versus fractured OD was calculated as number of cells per 100 μm2. Results The strain of E. faecalis used in this study showed moderate to heavy tubule invasion after 8 weeks. In the adhesion studies, significantly more bacteria adhered to fractured OD than to dentinal tubule walls (anova, P < 0.001). With respect to the tubule wall, adherence was greater in inner versus outer dentine (P = 0.02) and greater when bacterial adhesion was tested in chemically defined medium than in phosphate-buffered saline (anova, P < 0.001). Conclusions Although E. faecalis readily invaded tubules, it did not adhere preferentially to tubule walls. Initial colonization of dentinal tubules by E. faecalis may depend primarily on other factors.

Effects of post system and length on the strain and fracture resistance of root filled bovine teeth

Abstract: Aim To investigate ex vivo the effects of different post systems and lengths on the strain and fracture resistance of root-filled teeth. Methodology One hundred and thirty-five bovine incisors were sectioned 15 mm from their apices, root-filled and divided into three groups (n = 45): fibreglass post; prefabricated steel post; cast post and core. Each group was divided into three subgroups (n = 15) according to the post length: 5.0 mm; 7.5 mm; 10.0 mm. All teeth were restored with metal crowns. For strain-gauge measurement, two strain gauges per sample were used. The fracture resistance (N) was measured and the data were analysed with two-way analyses of variance, followed by the Tukey’s HSD test (α = 05). Results For all posts, decreased lengths resulted in increased microstrain values. However, the fibreglass posts were associated with lower increases when compared with cast post and cores and prefabricated steel posts, which showed microstrain values two times higher when the post length was 5.0 mm. The two-way analyses of fracture resistance values revealed that post length was statistically significant for the metal posts and not significant for the fibreglass post. The fracture mode analysis indicated that all groups tended to demonstrate root fractures in groups restored with metal posts and resin core fractures in groups restored with fibreglass posts. Conclusions The cast post and core when the length was 10.0 mm had the highest fracture resistance; however, the fibreglass post was effective with the three post lengths, with higher fracture resistance than metal posts when the length was 5.0 mm.

Dens invaginatus. Part 2: clinical, radiographic features and management options

Abstract: Aim To describe the possible clinical and radiographic features of this developmental anomaly, review previous treatment recommendations and suggest management options based on the classification of the problem. Summary This paper describes the clinical and radiographic features related to the different types of dens invaginatus and highlights those features which may indicate the presence of a previously undetected invagination. Aids to clinical diagnosis are described together with a description of the possible radiographic features, which may suggest the presence of an invagination. Previous treatment suggestions are described and suggestions as to possible management options, based on current endodontic knowledge and the classification of the problems are described. Key learning points • Thorough clinical and radiographic examination is required to diagnose and successfully treat minor to severe invaginations. • Modern clinical techniques may facilitate the management of invaginations once considered untreatable.

Decalcifying effect of 15% EDTA, 15% citric acid, 5% phosphoric acid and 2.5% sodium hypochlorite on root canal dentine.

Abstract: Aim To evaluate and compare ex vivo the decalcifying effect of 15% EDTA, 15% citric acid, 5% phosphoric acid and 2.5% sodium hypochlorite on root canal dentine. Methodology Two 2-mm-thick slices were cut from the coronal third of the root of 10 human incisors. Each slice was sectioned into two equal parts. Specimens were assigned to one of four groups (n = 10) for immersion in 20 mL of either 15% EDTA, or 15% citric acid, 5% phosphoric acid or 2.5% NaOCl, for three time periods (5, 10 and 15 min). The concentration of Ca2+ extracted from the dentine was measured by atomic absorption spectrophometry. The amount of calcium extracted was analysed using the Kruskal–Wallis test for global comparisons and the Mann–Whitney U-test for pairwise comparisons. Results In the three time periods, 15% EDTA and 15% citric acid extracted the largest amount of calcium, with no significant differences between them. The 2.5% NaOCl solution extracted insignificant amounts of calcium, whereas 15% EDTA extracted 86.72% of the calcium in the first 5 min, and 15% citric acid and 5% phosphoric acid had a similar pattern of calcium removal (77.03% and 67.08% in first 5 min, respectively). Conclusions Solutions of 15% EDTA, 15% citric acid and 5% phosphoric acid decalcify root dentine, with most calcium extracted during the first 5 min of action. The efficacy of 15% citric acid and 15% EDTA solutions was significantly greater than that of 5% phosphoric acid solution at each time period (5, 10 and 15 min).

Calcium ion release from calcium hydroxide stimulated fibronectin gene expression in dental pulp cells and the differentiation of dental pulp cells to mineralized tissue forming cells by fibronectin.

Abstract: Aim The effect of calcium ions on dental pulp cells was examined and the mechanism of dentine bridge formation by calcium hydroxide was investigated. Methodology Human dental pulp cells were treated with high concentration of calcium or magnesium ions for 24 h and fibronectin gene expression was measured by the quantitative PCR method. Human dental pulp cells were then cultured on fibronecin-coated dishes for 24 h, and osteocalcin and osteopontin gene expression, which are typical phenotypes of mineralized tissue forming cells, were measured by the quantitative PCR method. Results Fibronectin gene expression was stimulated by calcium ions dose-dependently. On the other hand, magnesium ions did not influence fibronectin gene expression. Furthermore, pulp cells cultured on fibronectin-coated dishes enhanced the expression of phenotypes of mineralized tissue forming cells. Conclusions Calcium ions released from calcium hydroxide stimulates fibronectin synthesis in dental pulp cells. Fibronectin might induce the differentiation of dental pulp cells to mineralized tissue forming cells that are the main cells to form dentine bridges, via contact with cells.

Root canal morphology of mandibular permanent molars at different ages

Abstract: Peiris HRD, Pitakotuwage TN, Takahashi M, Sasaki K, Kanazawa E. Root canal morphology of mandibular permanent molars at different ages. International Endodontic Journal, 41, 828–835, 2008. Aim To investigate differences in the root canal morphology of permanent mandibular molar teeth at various ages. Methodology Four hundred and eighty permanent mandibular first and second molars were examined. First and second molars were divided into six and five groups, respectively, according to the age of the patient at the time of extraction. Root canal morphology was studied using a clearing technique. The canal morphology of the mesial root was classified into three stages depending on its developmental pattern. When the root canal system was completely differentiated, the canal classification and the number of lateral canals and inter-canal communications were recorded. Vertucci’s classification was taken as the main reference. Canal morphology was compared amongst age groups. Results In both first and second molars, developmental stages of canal morphology amongst age groups were significantly different (P < 0.0001). The prevalence of inter-canal communications was highly significantly different in the first (P < 0.0001) and less significant in the second molar (P < 0.05). After completion of the canal differentiation, the mesial roots of first molars had type IV and II canal forms. The majority of the mesial roots of second molars had type I and III canals. C-shaped canals were found in 3% of second molars. Conclusions Mesial roots of first and second molars mostly had one large canal until 11 and 15 years of age, respectively. In both molars, the canal system was completely defined at 30‐40 years. The prevalence of inter-canal communications was low at young and old ages but high at intermediate ages.

Root form and canal morphology of mandibular premolars in a Jordanian population

Abstract: Aim To investigate the root canal anatomy of mandibular premolars in a Jordanian population. Methodology Nine hundred extracted mandibular premolars were examined. After the length of the teeth was measured, the presence of developmental grooves and furcated roots was noted. Following the preparation of access cavities, pulp tissue was removed and the canal systems were stained. The teeth were then rendered clear by demineralization and immersion in methyl salicylate. Cleared teeth were examined and the following features were evaluated: (i) type of root canals; (ii) presence and location of lateral canals; transverse anastomosis; (iii) location of apical foramina; and (iv) frequency of apical deltas. Results The mean lengths of first and second mandibular premolars were 22.6 mm (18–27.5 mm) and 22.2 mm (16–26.5 mm), respectively. Although the majority of the specimens corresponded to Vertucci’s classification scheme, analysis of this large data set revealed four additional root canal morphologies. Variable root canal morphologies were found in the mandibular first premolars; two separate apical foramina were found in 33% of the teeth with two canals, compared to 6.2% with one apical foramen. Teeth with three separate apical foramina were scarce (2.2%). The majority of the mandibular second premolars had a single canal; 72% of teeth possessed type I canal systems, whilst 22.8% of the roots had two canals with two separate apical foramina. Conclusions The prevalence of multiple canals in the investigated Jordanian mandibular premolars was high, especially for the second mandibular premolar, in comparison with previous studies performed on populations of different racial origin.

Electric pulp testing: a review.

Abstract: Electric pulp testing (EPT) has been available for more than a century and used in dental practices worldwide. This article provides an overview of this diagnostic aid. The PubMed database from 1953 was used initially; the reference list for pulp testing featured 1071 articles, and for EPT identified 121 papers. A forward search was undertaken on these articles and using selected author names. Potentially relevant material was also sought in contemporary endodontic texts, while older textbooks on endodontics, operative dentistry and pain revealed historic information and primary research not found electronically. A short account of the innervation of the pulp is followed by an historic overview. Clinical considerations discussed include tooth isolation, glove wearing and tester electrode placement. Orthodontic treatment, pacemaker wearing and patient medications are considered. Research applications are also discussed. While EPT is valuable, no single pulp testing technique can reliably diagnose all pulp conditions. Careful collection of patient history regarding the problem tooth and prudent use of appropriate radiographs are also helpful. The shortcomings of electric tests, especially in the case of immature and concussed teeth, must be understood. The demeanour of the patient and the responses given by control teeth also require careful consideration.

Ex vivo evaluation of the accuracy of two electronic apex locators during root canal length determination in primary teeth

Abstract: Aim To evaluate ex vivo the accuracy of two electronic apex locators during root canal length determination in primary incisor and molar teeth with different stages of physiological root resorption. Methodology One calibrated examiner determined the root canal length in 17 primary incisors and 16 primary molars (total of 57 root canals) with different stages of root resorption based on the actual canal length and using two electronic apex locators. Root canal length was measured both visually, with the placement of a K-file 1 mm short of the apical foramen or the apical resorption bevel, and electronically using two electronic apex locators (Root ZX II – J. Morita Corp. and Mini Apex Locator – SybronEndo) according to the manufacturers’ instructions. Data were analysed statistically using the intraclass correlation (ICC) test. Results Comparison of the actual root canal length and the electronic root canal length measurements revealed high correlation (ICC = 0.99), regardless of the tooth type (single-rooted and multi-rooted teeth) or the presence/absence of physiological root resorption. Conclusions Root ZX II and Mini Apex Locator proved useful and accurate for apex foramen location during root canal length measurement in primary incisors and molars.

Efficacy of rotary instruments with greater taper in preparing oval root canals

Abstract: AIM: To compare the preparation quality of two rotary systems and NiTi-hand files in oval root canals, and to evaluate the effect of canal dimensions on the preparation. METHODOLOGY: Ninety roots with oval root canals were selected. The middle third was cross sectioned at two levels and photographed. The maximum and minimum diameters of the root and canal were recorded. Teeth were distributed in three groups (n = 30) using stratified randomization, and prepared under simulated clinical conditions with Mtwo, ProTaper, or NiTi-hand files. The pre- and post-preparation photographs were traced and superimposed, the thickness of dentine removed was measured and the ratio of prepared canal outline was calculated. The impact of preparation system and canal dimensions on the quality of the preparation was evaluated using regression analysis. RESULTS: With regards to the ratio of prepared canal outline, no statistical significant difference was found between Mtwo (0.75 [95%CI: 0.69; 0.81]) and ProTaper (0.75 [95%CI: 0.69; 0.80]), but both systems performed significantly better than NiTi-hand files (0.65 [95%CI: 0.60; 0.71]). In six root canals in Mtwo-group (20%), and eight root canals in ProTaper-group (27%), the minimal thickness of dentine-wall after preparation was less than 0.5 mm. In contrast to the maximum diameter of the root canal, the minimum diameter influenced the quality of the preparation (P = 0.0006). CONCLUSIONS: No instrumentation technique was able to circumferentially prepare the oval outline of root canals. Nevertheless, instruments with greater taper (ProTaper and Mtwo) were more efficient than NiTi- hand files, but this was, in some cases, at the expense of remaining dentine-wall thickness.

Anomalous mandibular premolars: a mandibular first premolar with three roots and a mandibular second premolar with a C-shaped canal system

Abstract: Cleghorn BM, Christie WH, Dong CCS. Anomalous mandibular premolars: a mandibular first premolar with three roots and a mandibular second premolar with a C-shaped canal system. International Endodontic Journal, 41, 1005‐1014, 2008. Aim To describe unusual variations in the root morphology and root canal systems of mandibular first and second premolar teeth extracted for orthodontic reasons. Summary Normally mandibular first and second premolar teeth have single roots with single canals. A 15-year-old patient presented for orthodontic treatment and two mandibular premolar teeth were examined post-extraction. The mandibular first premolar exhibited three distinct, separate roots and the mandibular second premolar exhibited a C-shaped root canal system. The coronal morphology of each of the mandibularpremolarsrevealeddimensionsandanatomywithinnormallimits.Theincidence of a three-rooted mandibular first premolar is approximately 0.2%. Key learning points • Thorough clinical and radiographic interpretation is important in recognizing anomalous root and root canal systems. • The most common forms of root and canal systems and its aberrations must be understood to realize variations from normal do occur. • Successful root canal treatment requires an accurate diagnosis of the root canal system using all available aids. • Value of microcomputed tomography in the study of anatomy ex vivo and cone-beam tomography in clinical endodontics of complex premolar cases is increasing.

Technical quality of root fillings and periapical status in root filled teeth in Jönköping, Sweden

Abstract: Technical quality of root fillings and periapical status in root filled teeth in Jonkoping, Sweden

Opinions and attitudes of endodontists and general dental practitioners in the UK towards the intra-canal fracture of endodontic instruments. Part 2

Abstract: AIM: To investigate the attitudes and opinions of general dental practitioners (GDPs) and endodontists in the UK towards fracture of endodontic instruments. It was hypothesized that there would be no significant difference between GDPs and endodontists regarding their experience of fracture of endodontic instruments. METHODOLOGY: A pilot questionnaire was carried out on 20 postgraduate dental students to ensure that the questions were easily understood. This was followed by a further pilot survey on a group of GDPs and endodontists (50) to facilitate sample size calculation. The sample size comprised 330 systematically selected GDPs, and all endodontic specialists working in the UK (170). The questionnaire comprised both close-ended and partially close-ended questions in four categories: demographics; pattern of practice and experience of instrument fracture; management of fractured instruments; and unsuccessful management of fractured instruments. Nonrespondents were sent another two mailings (first and second reminders). After collecting the responses, data were analysed using chi-square and Linear-by-Linear Association tests at the 0.05 level of significance. RESULTS: The overall response rate was 75% (82.82% for endodontists and 70.92% for GDPs). Overall, 88.8% of respondents had experienced fractured instruments with a significantly higher proportion of endodontists (94.8%) compared with that of GDPs (85.1%). CONCLUSION: Both endodontists and GDPs were aware of most factors contributing to endodontic instrument fracture. With experience and knowledge, fracture of endodontic instruments was associated with the number of root canal treatments performed.

Influence of endodontic sealer cement on fibreglass post bond strength to root dentine.

Abstract: Aim To test the hypothesis that the composition of endodontic sealer cements and the time elapsed between root filling and fibreglass post fixation interferes with adhesion to root canal dentine. Methodology Sixty bovine incisor roots were divided into five groups (n = 12): CI, unfilled; SI, filled with a calcium hydroxide-based cement-Sealer 26, and immediate post fixation; S7, Sealer 26 and post fixation after 7 days; EI, filled with a zinc oxide and eugenol-based cement-Endofill and immediate fixation; and E7 Endofill and post fixation after 7 days. The posts were cemented with adhesive system and dual resin cement. Ten roots were cross-sectioned to obtain two 1-mm-thick discs for each cervical (TC), middle (TM) and apical (TA) third of the prepared root portion. The posts were submitted to a micropush-out test. The other two teeth were evaluated using scanning electron microscopy to analyse the bond interface. Data were analysed using anova, Tukey and Dunnett tests (P < 0.05). Results Group EI was associated with a significant reduction in bond strength values irrespective of the root region; TC = 3.50 MPa (P = 0.0001); TM = 2.22 MPa (P = 0.0043) and TA = 1.45 MPa (P = 0.003). Region of canal had an influence on the values for the cement used in group E7, in which only the TA presented differences from the CI. Conclusions Endofill interfered negatively with the bond to root dentine along its full length and in the TA when post fixation was delayed for 7 days. Bond strength decreased from crown to apex in all groups.

Technical quality of root fillings performed by dental students at the dental teaching centre in Reims, France.

Abstract: Aim To evaluate the technical quality of root fillings performed by undergraduate students at a dental teaching centre in France. Methodology A random sample of 419 records of patients who received dental treatment at the dental service of the teaching Hospital, in Reims, France between 2005 and 2006 was investigated. Evaluation of root filled was based on radiographical criteria defined by the French National Health Service. The length of root fillings, the radiodensity and the presence of voids in the root filling or between root filling and root canal walls were recorded and scored. Chi-square analysis was used to determine statistically significant differences between the technical quality of root fillings and tooth type. Results Of the 304 teeth included in the study, 69% had an adequate length of root filling and 42.7% had a dense root filling without voids; only 30.3% of teeth fulfilled these criteria at the same time. The relationship between the technical quality of root fillings and tooth type was statistically significant (P < 0.001), the highest percentage of adequate root fillings occurred in single-rooted teeth (36.1%). The highest percentage of inadequate root fillings according to the criteria of root filling length and lateral adaptation was found in molar teeth (71.9%). Conclusion Overall, the technical quality of root fillings performed by undergraduate students was poor.