W. P. Saunders

A Prospective Clinical Study of Periradicular Surgery Using Mineral Trioxide Aggregate as a Root-end Filling

A prospective outcome study of periradicular surgery using microsurgical techniques and root-end filling with mineral trioxide aggregate (MTA) was performed. Nonhealing endodontically treated teeth (n = 321) were included in the study. Surgery was completed under local anesthesia using a standardized clinical protocol. Patients were recalled periodically and examined for signs and symptoms of failure. Thirty-nine teeth were lost from recall. Of the 276 teeth examined, 163 showed complete healing radiographically with no other signs and symptoms; 82 teeth had no symptoms but incomplete or uncertain healing, and 31 teeth showed nonhealing (three had persistent pain despite evidence of complete radiologic healing and eight teeth did not heal for reasons unrelated to the surgical treatment). The overall success rate was 88.8%, including all teeth with no clinical symptoms. In this study, the use of MTA as a root-end filling, following microsurgical techniques, showed a high success rate.

Fibre-based post systems: a review

Objectives This article presents a review of published literature examining fibre-based endodontic post systems.Data sources A MEDLINE search was carried out for any articles in dental journals pertaining to fibre-based post systems. Wherever possible articles cited were obtained from the journals and where this was not possible abstracts were obtained. Where no abstract was available the article was not considered for evaluation.Data extraction Articles were reviewed by a single observer and subject to meeting inclusion criteria were included in the review. Fifty-nine articles were considered suitable for inclusion.Data synthesis Articles were divided into categories and a subjective description of the articles was made.Conclusions Review indicated that (1) most published literature on fibre-based posts took the form of laboratory analyses; (2) evidence for carbon-fibre posts far exceeds that for quartz-fibre posts; (3) laboratory evidence was contradictory and could not be used to inform practice reliably; (4) few clinical studies have been carried out though these have suggested fibre based posts may be clinically appropriate for restoration of the endodontically treated tooth; and (5) controlled prospective clinical trials evaluating fibre-based posts should be undertaken to inform use for clinical practice.

Influence of smear layer on the coronal leakage of thermafil and laterally condensed gutta-percha root fillings with a glass ionomer sealer

The effect that two methods of root canal obturation, combined with removal of the smear layer, had on coronal leakage was studied in vitro. Single-rooted teeth with mature apices were prepared chemomechanically and divided into two groups of 72 teeth each. One of the groups was treated with 40% citric acid and 2% sodium hypochlorite to remove the smear layer. The teeth were then subdivided and obturated using the glass ionomer sealer, Ketac Endo and either lateral condensation or Thermafil. After storage for 7 days or 4 months, the specimens were evaluated for coronal leakage using Indian ink. After 90 h, each root was split longitudinally and the maximum extent of leakage was measured using a stereomicroscope at x6 magnification. After 7 days, there was significantly less leakage in those teeth obturated with Thermafil without smear layer compared with the other groups (p < 0.05). After 4 months, there was no significant difference in leakage between the groups (p > 0.05).

Effect of noncutting tipped instruments on the quality of root canal preparation using a modified double-flared technique.

Fifty-one extracted human first molar teeth with intact crowns and mature root apices were divided into three groups. Root curvature was determined. One of the root canals in the mesial root of lower molars, or the mesiobuccal root in maxillary molars, was prepared in one of three ways. In group 1 the root canals were instrumented using a modified double-flared technique with noncutting tipped files (Flex R); in group 2 the same files were used with a step-back technique. Group 3 was prepared with conventionally tipped files (K-Flex) using the step-back technique. A low viscosity polyvinyl siloxane impression material was injected into the prepared root canals and the specimens were decalcified, dehydrated, and cleared. The preparation was evaluated subjectively according to various desirable or undesirable criteria. A rating for overall quality of preparation was given. Statistical analysis showed that the teeth in group 1 had better overall preparation than those in group 3 (p < 0.05). There were no other statistically significant differences between the groups. The mean time required for each preparation technique was not statistically significantly different (p > 0.1). The use of a modified double-flared technique with non-cutting tipped files was shown to be an effective method for the preparation of curved root canals.

In Vitro Evaluation of Furcal Perforation Repair Using Mineral Trioxide Aggregate or Resin Modified Glass Ionomer Cement with and without the Use of the Operating Microscope

This study evaluated in vitro the effect of using the operating microscope on repairing furcation perforations using Vitrebond or mineral trioxide aggregate. Forty-six human molar teeth were mounted into a jig attached to a simulated jaw. The teeth were allocated randomly to four groups (n = 10). Furcal perforations were made in the teeth using an ISO 012 round bur in a slow-speed hand-piece. Each material was used to repair a group of teeth with and without the use of the operating microscope. The remaining six teeth provided positive and negative controls. All groups were stored in 100% humidity, and the repair materials were allowed to set for 72 h at room temperature before being assessed for the quality of placement under x26 magnification. Leakage at the repair was then tested using India ink; the teeth were demineralized, dehydrated in alcohol, and rendered transparent in methyl salicylate. Dye penetration into the furcation repair was evaluated at x26 magnification. There was no difference in the acceptability of the repair with either material whether or not the operating microscope was used. The perforations repaired with mineral trioxide aggregate leaked significantly less to the tracer dye than those repaired with Vitrebond (p < 0.001).

Coronal leakage of obturated root canals after long-term storage using a polymicrobial marker

This in vitro study investigated the effect of long-term storage on the coronal leakage of a microbial marker on teeth root filled with lateral condensation of cold gutta-percha and one of two sealers. Sixty single-rooted teeth were prepared chemomechanically to a size 40 master apical file. The teeth were divided into two groups of 20 teeth each and obturated with gutta-percha using either Apexit or Tubliseal EWT sealer. The teeth were stored for 6 months in artificial saliva and tested for leakage using a marker consisting of S. sanguis and P. intermedia. The teeth were checked for bacterial leakage daily for 90 days. All positive control teeth leaked after 24 h, while the negative control teeth remained uncontaminated throughout the test period. Leakage reached the apex through the experimental teeth at the earliest at 17 days and at latest at 88 days. Fifty percent and 70% of the specimens of the Apexit and Tubliseal EWT groups respectively showed leakage at 90 days. There was no statistically significant difference (p > 0.05) between the two groups.

Comparative Evaluation of Calcium Hypochlorite and Sodium Hypochlorite on Soft-tissue Dissolution

INTRODUCTION The aim of this study was to compare in vitro the tissue-dissolution properties of 5% and 10% calcium hypochlorite (Ca(OCl)(2)) with two concentrations (1.36% and 4.65%) of proprietary sodium hypochlorite (NaOCl) on bovine muscle tissue. METHODS The available chlorine concentration of each solution was determined using iodometric titration. Tissue specimens from bovine muscle were weight adjusted (50 ± 5 mg). Ten tissue specimens in each group were immersed in 5 mL each test solution, removed after 5 minutes, blotted dry, and weighed. The process was repeated every 5 minutes with a fresh 5-mL aliquot of the test solution for 60 minutes or until complete tissue dissolution, whichever was quickest. The percentage weight loss of the specimens was calculated over the experimental period. RESULTS Available chlorine concentrations of the irrigants ranged from 1.36% to 4.65%. All solutions dissolved tissue completely after 60 minutes except 5% Ca(OCl)(2) (99.4% dissolution). Between the 35- and 60-minute test readings, there were no significant differences between the solutions. Chlorax (4.65% NaOCl) (Cerkamed Group, Nisko, Poland) dissolved tissue quicker during the first 35 minutes (P < .05). In this period, the weight loss with 10% Ca(OCl)(2) differed from Chlorax at all time intervals except at 5 and 35 minutes (P < .05); 5% Ca(OCl)(2) showed no significant differences with 10% Ca(OCl)(2) and Tesco bleach (1.36% NaOCl) (Tesco Stores Ltd, Chestnut, UK) in the first 35 minutes except at the 5-minute measurement. CONCLUSIONS Within the limitations of this study, Chlorax (4.65% NaOCl) dissolved tissue faster than the Ca(OCl)(2) solutions and Tesco thin bleach (1.36% NaOCl) over the first 35 minutes, but there were no significant differences among the solutions thereafter.

Comparison of three instruments in the preparation of the curved root canal using the modified double-flared technique

Fifty-one extracted intact human first molar teeth with mature root apices were radiographed in a standardized way; their root curvature was determined and they were divided into three groups. One root canal in the mesial root of the mandibular molars, or the major mesiobuccal root in maxillary molars, was prepared with the modified double-flared technique, in one of three ways. The modified double-flared technique involves coronal flaring followed by working length determination and apical preparation. In group 1, unmodified tipped instruments (Flexofile) were manipulated with a balanced force technique. In groups 2 and 3, Flexogates files and Canal Master U files were operated in the manner recommended by the manufacturers. After preparation, the teeth were radiographed. The processed images of the root canals were traced using an image analysis computer software package. Comparisons were made between the preoperative and postoperative shapes of each root canal. A low viscosity polyvinyl siloxane was injected into the prepared root canals and the specimens were demineralized, dehydrated, and cleared. The preparation was evaluated subjectively according to desirable or undesirable criteria. The overall quality of preparation was rated. Statistical analysis showed that there was no significant difference in the overall change of area between the three groups (p = 0.994). There was a significant proportional increase in mesiodistal width in the coronal part of the canals in the Canal Master U group and more of the instruments in this group fractured.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of periradicular periodontitis in a Scottish subpopulation found on CBCT images

AIM To investigate the prevalence of periradicular periodontitis (PRP) using cone-beam computed tomography (CBCT) scans in a retrospective cross-sectional epidemiological study in a Scottish subpopulation. METHODOLOGY Of the 319 CBCT scans performed at Dundee Dental Hospital between November 2009 and July 2012, 245 dentate scans of patients over 18 years of age were included and 3595 teeth examined. Odds ratios were calculated, and the association between root filling and posts with PRP was determined. RESULTS Radiological signs of PRP were detected in 209 teeth (5.8%) in 96 patients (male = 53, female = 43) of which 145 (69.4%) were measurable and 64 (30.6%) appeared as periapical widening. Most lesions were seen in the 46-55-year age group and in maxillary anterior teeth (35.4%); 47.4% (n = 81) of the total root filled teeth (n = 171) had PRP. Of the root filled teeth with lesions, approximately half (50.6%) had an inadequate root filling. Teeth with crowns, but not root filled, accounted for 17.7% of PRP. Periapical changes were detected on a high proportion of teeth with post-retained crowns (70.7%). The presence of a root filling was significantly associated with PRP (z = 17.689 P < 0.0001; odds ratio 16.36 < 23.17 < 32.83, 95% CI) and the presence of a post (z = 10.901 P < 0.0001; odds ratio 21.36 < 41.8021 < 81.78, 95% CI). CONCLUSIONS The prevalence of PRP in a Scottish subpopulation was 5.8%. The presence of a root filling or a post-retained crown was significantly associated with the presence of PRP as determined by CBCT scans. The prevalence of periradicular disease in root filled teeth remains high in the Scottish population.

Looking forward: educating tomorrow's dental team

This publication reports a meeting of the stakeholders of dental education in the UK, hosted by the Council of Heads and Deans of Dental Schools (CHDDS). The meeting, held in Manchester, UK on 4–5 October 2007, occurred within days of the seventh anniversary of a dental hospitals and schools policy retreat hosted by the then Council of Deans of Dental Schools and the Association for Dental Hospitals. The proceedings of the retreat, intended to raise awareness and stimulate discussion on matters important to the planning of the future provision of dental education in the UK, were published in the form of a supplement to the European Journal for Dental Education (1). The principal purpose of the meeting of stakeholders of dental education reported in the present publication was to raise and stimulate discussions on issues considered important to the further development of dental education in the UK. A secondary, but by no means less important purpose of the meeting was to give members of the CHDDS opportunity to interact with other stakeholders in dental education and, in the process, facilitate a shared understanding of existing and, in certain respects increasing tensions and challenges in the UK dental education system.