bluuebunny/crossref_metadata_2025_split huggingface dataset:
A clinical and roentgenological study of 55 cases of root perforation
Authors: KVINNSLAND I. , OSWALD R. J. , HALSE A. , GRØNNINGSÆTER A. G. 
Published: September 2007

Summary. The treatment outcome of 55 root perforations in man were related to pretreatment conditions and various treatment procedures used, with a mean recall period of 3 years 5 months. In this study maxillary teeth were perforated three times more often (74.5 per cent) than mandihular teeth (25.5 per cent); 47 per cent of the perforations were due to endodontic and 53 per cent due to prosthodontic treatment. The buccal and mesial root surfaces as well as the midroot areas w ere most often perforated. In 25 per cent, radiographic changes were directly related to the perforated areas.Twenty‐eight perforations were repaired by orthograde fillings with gutta‐percha and Kloro‐percha N‐ø; eight received a combined orthograde and surgical repair, and in only three cases a surgical approach was used. Four cases received no treatment but were recalled, and twelve perforations showed a size and location hopeless for repair; the teeth were therefore extracted. Five failures of the primary orthograde treatment group later underwent surgical treatment and were followed up for 3 years 3 months.The overall success rate in the primary treatment group of teeth was 56 per cent while 36 per cent became failures. Five failures were retreated, and four of these became successful. A combined orthograde and surgical repair of the perforations provided the most favourable outcome with 92 per cent successful.The study stresses the importance of preventing this type of treatment complication.
Capacitance effect of rubber gloves on electric pulp testers
Authors: TREASURE P. 
Published: September 2007

Summary. Electric pulp testers (EPTs) are widely used to assess tooth pulp vitality. With many unipolar EPTs the electrical circuit is completed through the operator. Since dentists now routinely wear rubber gloves, these might be expected to provide electrical insulation, and therefore to break the circuit. The objective of this investigation was to define the electrical effect of wearing rubber gloves.Two battery‐powered unipolar EPTs were examined using a digital storage oscilloscope with an input impedance of 1 MΩ. The probe tip was connected directly to the positive input lead of the oscilloscope. Three conditions were tested: (i) with the conductive handle connected directly to the negative input lead; (ii) with the ungloved operator holding the negative input lead in one hand and the conductive handle of the EPT in the other; and (iii) holding the conductive handle in a gloved hand.While the two EPTs produced different patterns of voltage spike, for each there was no difference between conditions (i) and (ii). However, when the conductive handle was held in a gloved hand (condition iii), there was a reduction in peak negative voltage and a change in wave form with positive overshoot. The alteration in wave form could be reproduced by substitution of the operator's gloved hand with a capacitance of 47 pF.These results support the hypothesis that a rubber glove acts partly as a capacitor in series with the electric pulp tester, and will alter the performance of EPTs unless the glove is bypassed electrically.
Evaluation of dowel space preparation on the apical seal using an image processing system
Authors: DE NYS M. , MARTENS L. , DE COSTER W. , THYS M. 
Published: September 2007

Summary. The effect of post preparation on the apical seal of endodontically treated specimens was studied. The canals prepared in bovine bone were instrumented and obturated using five obturation techniques: the silver point technique, the lateral condensation of gutta‐percha technique, the warm vertical condensation of gutta‐percha technique, the Hygenic Ultrafil injection system and the Obtura technique.In addition to these five control groups, the five experimental groups were also subjected to post preparation. In the latter group, the gutta‐percha was removed with an engine‐driven root canal reamer 48 hours after obturation. Both the control and experimental groups were suspended in a 0.5 per cent crystal violet solution for 48 hours. After dye penetration, the specimens were immersed in liquid nitrogen and then split longitudinally.Linear measurements of the resultant apical dye leakage were determined by image processing. For each obturation technique, all specimens in both the control and experimental groups were recorded if they showed leakage.Using Fisher's exact probability test, it was shown that there was no significant difference between the obturation techniques used.
The dentine‐removing characteristics of an ultrasonically energized K‐file
Authors: BRIGGS P. F. A. , GULABIVALA K. , STOCK C. J. R. , SETCHELL D. J. 
Published: September 2007

Summary. This in vitro study evalutated the pattern of dentine removal when an ultrasonically energized file (Cavi‐Endo‐size 25 file) was applied to flat surfaces of dentine under standardized conditions. The influences of power setting, interfacial force between file and dentine, direction of file oscillation and operator‐assisted movement were examined. Impressions of the inswtrumented surfaces trevealed characteristic patterns consisting of a series of oblique creste, each one parallel to the next and separated by a constant distance along the line of contact with the file. Determination of height, width and separation of these crests with a Reflexd microscope aided objective asserssmennt.The simplest pattern was formed when the energized file was held against the dentine (power steeing = 1; interfacial force = 30g). Increasing the power setting to 8 caused deeper troughs over the apical 5 mm. The width of the crests corresponded to the taper of the file except at the apical tip where the crests were relatively wider. However, increasing the interfacial force to 60 g reduced the efficiency of the apical part of the file.The superimposition of operator‐induced movement greatly increased the extent of dentine removal, resulting in a tapering groove with a persistent crestal pattern. Oscillation of the file perpendicular to the dentine surface had a significantly greater influence on dentine removal, producing a deeper groove than was obtained with oscillation parallel to the surface.The findings may be of reevance in aiding controlled root canal preparation when using the Cavi‐Endo instrument.
A one visit apicectomy technique using calcium hydroxide cement as the canal filling material combined with retrograde amalgam
Authors: CROSHER R. F. , DINSDALE R. C. W. , HOLMES A. 
Published: September 2007

Summary. A prospective study was set up to evaluate a one‐visit apicectomy technique. Calcium hydroxide cement was used as the root canal filling material. The calcium hydroxide cement set rapidly and clearly revealed the position, size and outline form of the root canals at the level of resection. This facilitated preparation of the apical cavities to a depth of 3 mm. Each cavity was varnished before placement of the amalgam.Sixty‐eight patients (93 teeth) were included in the study. Five patients (8 teeth) were lost to follow‐up. The success rate, based on clinical and radiographic examination after a minimum of 2 years, was 91.8 per cent.
Comparison of curved canal shape using filing and rotational instrumentation techniques
Authors: CIUCCHI B. , CERGNEUX M. , HOLZ J. 
Published: September 2007

Summary. The shaping of curved canals produced by rotational and filing instrumentation techniques was compared in 40 human molar root canals which were prepared in vitro. The tech niques used for filing were the stepback and the serial, and for rotational instrumentation were the ‘balanced force’ and an experimental technique, similar to the balanced force concept, but featuring only clockwise rotated instruments.The results were collected from pre‐ and postoperative radiographs as well as from scanning electron microscope analysis of longitudinally ground half‐sections of the roots. Each preparation was qualitatively rated for its centering, flow, taper, apical design and wall surface appearance.The stepback shapings consistently presented the best taper and apical stop design along with scratch‐free surfaces. The serial technique produced the best centered flow and apically deigned preparations.The rotational techniques produced less consistent results. With the exception of some straightened specimens, the balanced force concept proved to be effective at least for the shaping of moderately curved canals. The lack of taper as well as the absence of apical stop in the balanced force shapings have been found to be more inherent in the concept of shaping than in the technique of the preparation itself. The experimental rotational preparations showed almost exactly the same shaping patterns as the balanced force ones, apart from better taper and apical design but poorer flow and visible instrument scratches. The latter two observations were related to the use of non‐tip‐smoothed instruments.
An evaluation of the retrograde apical seal using dentine bonding materials
Authors: MCDONALD N. J. , DUMSHA T. C. 
Published: September 2007

Summary. The purpose of this investigation was to compare in vitro retrograde apical leakage of four dentine bonding procedures with amalgam and hot burnished gutta‐percha.Single‐rooted teeth were prepared using a standardized stepback flare technique with recapitulation. The teeth were obturated with gutta‐percha and sealer using the lateral condensation technique and placed into a saline bath at 37°C for 30 days. The teeth were then randomly divided into seven groups of 22 teeth each. Groups I and II were apically bevelled, and dentine bonding agent with composite resin and dentine bonding agent with unfilled resin applied to the bevelled root faces, respectively. Groups III, V and VI were apically bevelled and prepared to accept a retrograde filling material of dentine bonding agent with composite resin, amalgam with cavity varnish and amalgam without cavity varnish, respective. Group IV had dentine bonding agent and unfilled resin applied to the apical third of the root, and Group VII was apically bevelled and the gutta‐percha hot burnished. The teeth were then placed into a water bath at 37°C for 30 days, stained with silver nitrate and the linear dye penetration measured.The lowest mean leakage value was recorded in Group I, i.e. dentine bonding agent and composite resin (0.31 mm), and the highest value was observed in group VII, i.e. hot burnished gutta‐percha (4.60mm); the difference was statistically significant.
A comparison of subcutaneous connective tissue responses among three different formulations of gutta‐percha used in thermatic techniques
Authors: LEONARDO M. R. , UTRILLA L. S. , ROTHIER A. , LEONARDO R. T. , CONSOLARO A. 
Published: September 2007

Summary. A study of the subcutaneous connective tissue response of 24 white rats to three different formulations of gutta‐percha was undertaken. The prepared specimens were examined under the light microscope after intervals of 7, 21, 60 and 120 days.The results showed identical tissue responses after the initial period of 7days. However, after 120 days the gutta‐percha supplied with the Ultrafil system presented mature granulation tissue with neither oedema nor vascular congestion, in contrast to the responses observed with the McSpadden and Obtura formulations.
An in vitro study to compare impact fracture resistance of intact root‐treated teeth
Authors: McDONALD A. V. , KING P. A. , SETCHELL D. J. 
Published: September 2007

Summary. The aim of this in vitro study was to determine the effect on impact fracture resistance of three methods for restoration of root‐treated lower incisor teeth with otherwise intact natural crowns. In a control group (Group I) laterally condensed gutta‐percha filled the entire root canal, whereas part of the root filling was removed to enable insertion of a 1 mm diameter post in the other two groups. Stainless steel posts were placed in Group II and experimenral carbon fibre reinforced carbon (CFRC) in Group III. A composite resin luting agent was used to lute the posts, and standardized composite resin restorations were placed in each access cavity.Fifteen specimens of each group were tested to failure with a single impact force applied at 90 degrees to the mid‐point inciso‐cervically on the labial surface. The peak force, peak energy, and first peak total energy required to fracture each specimen were recorded. The results showed no significant difference between the three groups, nor was a difference in the mode or site of fracture observed.The results suggested that there is no advantage from the point of view of fracture mechanics in ‘restoring’ intact root‐treated teeth with either stainless steel or carbon fibre reinforced carbon rods.
Detection of bacteria in histological sections of the dental pulp
Authors: WATTS A. , PATERSON R. C. 
Published: September 2007

Summary. A series of deep cavities with and without traumatic pulpal exposures were prepared in the maxillary molars of albino rats. They were left untreasted for various time intervals before killing.Demineralized sections were prepared in a mesiodistral plane and stained to demonstrate the presence that were grossly contaminated, bacteria were detected in the majority of sections. In the roor canaks and periapical tissues, bacteria were detected in only a minority of sections.It is considered that serial sections stained to demonstrate bacteria are necessary for the detection of bacteria that the present in only small numbers in the tissue. The demonstration of small numbers of micro‐organisms in specific zones of the pulp remains problematic. Failure to detect stained bacteria in histological sections is not absolute proof of their absence.
Assessment of leakage in the restored pulp chamber of endodontically treated multirooted teeth
Authors: SAUNDERS W. P. , SAUNDERS E. M. 
Published: September 2007

Summary. The leakage associated with restorative materials placed within the pulp chamber of maxiliary and mandibular molars was studied in vitro. The root canals and pulp chambers of 69 extracted teeth were prepared chemomechanically and scaled with gutta‐percha and Tubliseal using cold lateral condensation. The teeth were divided into five groups. Gutta‐percha was removed from the pulp chambers of three of the groups of 15 teeth and filled with one of three materials, a glass ionomer cement, a cermet cement or an amalgam. The guttapercha was removed from the pulp chamber in the fourth group of nine teeth, which were left unfilled. The gutta‐percha in the pulp chambers of the fifth group of teeth was left intact.The teeth were suspended in Indian ink, thermocycied for 24 hours and stored for a further 48 hours at 37°C. They were then demineralized and cleared and the degree of coronal leakage was assessed. Those teeth with no filling in the pulp chamber showed extensive leakage. The gutta‐percha‐filled group demonstrated greater leakage than did the groups in which other restorative materials had been employed (P<0.01). No significant differences in leakage occurred between the other groups (P>0.05). It is recommended that the pulp chamber of molars should be restored with a filling material following root canal treatment.
Root canal anatomy of mandibular second molars
Authors: MANNING S. A. 
Published: September 2007

Summary. The root canal anatomy of 19 mandibular second molars with C‐shaped canals was investigated by rendering the roots transparent and allowing the canal system to be observed by black ink infiltration. The presence of three root canals was most frequent, and lateral canals were found in all roots. Transverse anastomoses were found in 15 of the 19 roots. The apicaf foramen was most commonly situated away from the apex, and apical deltas were found in 16 of the 19 roots. The C‐shaped canals were found more frequently in Asians than in other racial groups (P < 0.02).The formation of C‐shaped roots and their racial predilection is discussed. A case report of the root canal treatment of a C‐shaped canal is included and suggestions are made concerning suitable procedures for use in root canal treatment of these complex canal systems.
A quantitative microleakage study on a new retrograde filling technique
Authors: WU M.‐K. , KEAN S. D. , KERSTEN H. W. 
Published: September 2007

Summary. An in vitro endodontic leakage model was used to compare the sealing ability of conventional retrograde amalgam fillings with a new retrograde filling technique by measuring dye leakage quantitatively.The new technique consisted of retrograde preparation of the root canal using the Endocursor1, an endodontic handpiece. The canal was then filled with sealer and injection‐moulded gutta‐percha, using either the Hygenic Ultrafil2 system or the Unitek Obtura3 method. In both cases the guttapercha was vertically condensed and subsequently cold‐burnished.The two experimental groups and the amalgam group each consisted of 20 extracted human canine teeth and lower premolars. The results were analysed statistically by ANOVA and a Student‐Newman‐Keuls multiple comparison test. After 1 week at 37°C, very little leakage was observed in the amalgam and gutta‐percha groups. After a second week, during which leakage was enhanced by gas pressure, leakage in the amalgam group was significantly greater than that in the gutta‐percha groups (P 0.01). There were no significant differences between the two experimental gutta‐percha groups. It is concluded that the new retrograde filling technique causes less leakage than the conventional amalgam retrograde filling technique in an in vitro model.
The curriculum in endodontology at the Academic Centre for Dentistry Amsterdam (ACTA), The Netherlands
Authors: WESSELINK P. R. 
Published: September 2007

Summary. At the Academic Centre for Dentistry, Amsterdam (ACTA) clinical endodontics is taught and practised in a general clinic supervised by general dental practitioner instructors; they are continuously trained and supported by the endodontic staff, who ire members of the Department of Cariology and Endodontoiogy. The scientific basis of endodontology and the theory of clinical endodontic procedures are taught by the endodontic staff, primarily by using a textbook, a clinical manual, videotapes and a computer program, all accompanied by detailed instructional objectives. During their preclinical training, which allows 63 hours for practising procedures and performing several clinical tests, the students are taught one basic technique to prepare and fill root canals and to restore endodontically treated teeth. This technique, accompanied by clearly outlined criteria, is also used in the patient clinic.In the experience of the staff, who are limited to endodontology, the use of manuals, audiovisual aids and instructional objectives has been very beneficial, and the student's assessment of the endodontology course was, in general, very favourable. Although the clinical results are quite good, the endodontic staff feel that there is still some room for improvement of the teaching. Finally, an elective period has recently been introduced.
The organization and running of postgraduate endodontic ‘hands‐on’ courses
Authors: SAUNDERS E. M. 
Published: September 2007

Summary. Considerable preparation, planning and detailed organization are necessary if endodontic ‘hands‐on’ courses are to be stimulating and worthwhile for participant and teacher alike. Projection facilities, lighting, seating and working surface requirements must be checked immediately on arrival at the venue.The format, although flexible enough to allow for the wide range of knowledge and practical ability found within any one group, must adhere to and stress the current fundamentals in endodontic teaching. Not only can information and skill in diagnosis, root canal preparation and obturation be taught in a ‘hands‐on’ format, but rubber dam isolation techniques can also be practised very successfully.Tutors must be prepared to demonstrate personally their clinical ability and experience of principles and techniques taught during the course.Post‐course feedback can be an extremely useful means of ensuring that ‘hands‐on’ courses are relevant, with the appropriate practical emphasis required by the general dental practitioner, as well as the necessary stress on endodontic principles.
Continuing education in endodontology in The Netherlands
Authors: WESSELINK P. R. 
Published: September 2007

Summary. The Netherlands Society for Endodontology has developed a 5‐year plan for continuing education that served as a guideline for two baste courses in endodontology. The 2‐day basic course has been attended by over 2000 dentists, and has been very much appreciated according to the evaluation outlined in this article. The development and content of these courses are described.Over the past 10 years it has been shown that there is a high demand for continuing education in endodontology in The Netherlands, and that a properly designed and presented course may be very successful.
The effect of citric acid treatment on periodontal healing after replantation of permanent teeth
Authors: ZERVAS P. , LAMBRIANIDIS T. , KARABOUTA‐VULGAROPOULOU I. 
Published: September 2007

Summary. The aim of this study was to evaluate the effect of surface demineralization on the healing of 120 replanted teeth in fifteen 8‐ to 16‐month‐old dogs. Replanted teeth were divided into two groups (A and B). In group A, teeth were replanted following planing of the entire root surface. In group B, teeth were replanted following planing and surface demineralization with citric acid. Replanted teeth were splinted for 7 days, and observation periods were 3, 14 and 56 days. A total of 95 teeth and their surrounding tissues were examined histologically under a light microscope.Histological examination of specimens 3 days after replantation revealed that initial reunion between the root and the alveolar periodontal ligament fibres was via a fibrin‐like network in both groups. Fourteen days after replantation histologiesl observations showed superior healing in group B with regard to epithelial condition, periodontal ligament fibre reattachment to the root surface, resorption and functional arrangement of the periodontal ligament fibres. By 56 days after replantation, healing was superior in group A; group B was characterized by severe inflammatory and replacement resorption. These results indicated that surface demineralization had an initial positive effect, but later led to impaired healing.
Flare‐up rate of single‐visit endodontics
Authors: TROPE M. 
Published: September 2007

Summary. The purpose of the study was to compare the flare‐up rate for single‐visit endodontics among teeth without radiographic or clinical signs of apical periodontitis, those with radiographic or clinical signs of apical periodontitis not previously root‐treated, and those with apical periodontitis where retreatment was performed.All teeth were instrumented to a predetermined minimum size with a 0.5 per cent solution of sodium hypochlorite being used as the irrigant. The root canal was obturated without regard to the presence or absence of symptoms or diagnosis of the apical condition. The patients were given written postoperative instructions and a prescription for 600 mg ibuprofen to be taken if mild to moderate pain developed. If severe pain and/or swelling developed, the patient was instructed to telephone immediately and was considered to have had a flare‐up.Teeth without signs of apical periodontitis did not have any flare‐ups. One flare‐up occurred in 69 teeth with signs of apical periodontitis not previously root‐treated. The majority of the flare‐ups (3 of 22 teeth) occurred in teeth with signs of apical periodontitis requiring retreatment.