bluuebunny/crossref_metadata_2025 huggingface dataset:
In‐vitro antibacterial susceptibility of bacteria taken from infected root dentine to a mixture of ciprofloxacin, metronidazole and minocycline
Authors: HOSHINO E. , KURIHARA‐ANDO N. , SATO I. , UEMATSU H. , SATO M. , KOTA K. , IWAKU M.
Published: September 2007

The aim of this study was to clarify the antibacterial effect of a mixture of ciprofloxacin, metronidazole and minocycline, with and without the addition of rifampicin, on bacteria taken from infected dentine of root canal walls. The efficacy was also determined against bacteria of carious dentine and infected pulps which may the precursory bacteria of infected root dentine. This efficacy was estimated in vitro by measuring bacterial recovery on BHI‐blood agar Plates in the presence or absence of the drug combination. Bacteria ranging in number from 102 to 106 occurred in samples of infected root dentine (27 cases). However, none was recovered from the samples in the presence of the drug combination at concentrations of 25 μg ml‐1 each. The respective drug alone (10, 25, 50 and 75 μg ml‐1) substantially decreased the bacterial recovery, but could not kill all the bacteria. Bacteria taken from carious dentine (25 cases) and infected pulps (12 cases) were also sensitive to the drug combination. These results may indicate that the bactericidal efficacy of the drug combination is sufficiently potent to eradicate bacteria from the infected dentine of root canals.
Haemostasis in periradicular surgery
Authors: WITHERSPOON D. E. , GUTMANN J. L.
Published: September 2007

The successful performance of endodontic surgical procedures is predicated on many factors. However, the ability of achieve sustained tissue haemostasis in the surgical site is crucial to the performance of these procedures. This achievement improves vision in the surgical site, minimizes surgical time, enhances the surgical procedures (root‐end resection, preparation and filling), and reduces surgical blood loss, postsurgical haemorrhage and postsurgical swelling. A multitude of materials have used in dentistry and medicine to achieve both generalized and localized haemostasis, many without full assessment of their biological implications. The purpose of this paper is to provide a thorough and critical review of these materials from the perspective of surgical endodontics, highlighting their development, application and potential role in achieving proper haemostasis.
Variation in the microleakage produced by four different techniques in root fillings in a simulated root canal model
Authors: PATHOMVANICH S. , EDMUNDS D. H.
Published: September 2007

An in‐vitro investigation was performed to assess the extent of apical microleakage in simulated canals in clear resin blocks. Four different methods of producing dye penetration were employed: passive dye penetration alone, centrifugation alone, vacuum plus passive dye penetration, and increased pressure plus passive dye penetration. Forty simulated root canals were prepared and obturated. The specimens were randomly allocated into four groups and each group was subjected to a different leakage technique using methylene blue dye as the detector. The maximum apical dye penetration observed through each of the four faces of the blocks was recorded. There were large variations in the leakage recorded in each individual specimen and between the specimens within each group. There were statistically significant differences between passive dye penetration and each of the other three techniques. There was no significant difference between the centrifugation, vacuum and pressure techniques.
Microbiological root canal sampling: diffusion of a technology
Authors: MOLANDER A. , REIT C. , DAHLÉN G.
Published: September 2007

Diffusion is the process whereby a technology enters and becomes part of the health‐care system. In the present study, diffusion of microbiological root canal sampling (MRS) among general dental practitioners within the city of Gothenburg was observed for 25 years, from the establishment of the Laboratory of Oral Microbiology in 1966. Laboratory records at 5‐year intervals were analysed and adopters were categorized as‘occasional’(1‐2 samples/year), 'selective’(3‐10) or‘regular’(>10) samplers. The diagnostic accuracy was assessed by analysing the results of culturing 5 74 samples referred in 1986. The acceptance rate varied between 2.9 and 5.1%, except in 1986 when 10.1% of the practitioners in the area referred root‐canal samples. While a minority of the adopters used MRS as a standard procedure, the strategy appeared to be directed towards selection of special cases. The results of culturing revealed a predominance of facultatives. Although evidence of contamination was found, the practitioners frequently appeared to produce valid microbiological samples.
Reasons for dentists’ acceptance or rejection of microbiological root canal sampling
Authors: MOLANDER A. , REIT C. , DAHLEN G.
Published: September 2007

Microbiological root canal sampling (MRS) has been found to be used by only a few Swedish general dentists. The present study addresses the reasons for their acceptance or rejection of the technology. A questionnaire was mailed to 240 general dentists practising within the city of Goteborg. The questionnaire concerned certain practice characteristics and attitudes to MRS. The data showed that MRS is mainly performed by dentists working with adult patients in private practice. The technology is rarely used routinely, but is applied in selected cases. The main reason for non‐adoption seems to be a perceived lack of relative advantage over conventional treatment strategies. Furthermore, opinions regarding the complexity and observability of the technology appear to influence acceptance significantly.
Factors affecting the cutting ability of sonic files
Authors: LUMLEY P. J. , HARRINGTON E. , ASPINWALL E. , BLUNT L. , WALMSLEY A. D. , MARQUIS P. M.
Published: September 2007

The aim of this study was to investigate the cutting ability of sonic files. A model system was developed and the following variables evaluated: file type, Heliosonic or Shaper; file length, 21 or 29 mm; power, air inlet ring opening of half or fully open; stroke length, 2 or 4 mm; stroke rate, one or two cycles per second; and load 50 or 100 g. A 26 full‐factorial analysis with two replications into the effect of the above variables on the cutting ability of the MM1500 sonic instrument was performed. A new size 25 file was used for each cut, together with water irrigation, and the substrate used was 1‐mm thick sections of bovine bone. The differences between the variables were significant (ANOVA, P< 0.001). However, examination of the F‐values showed that the most significant variable to affect cutting was load, followed by power, file type, stroke length and stroke rate, with the least significant variable being file length. The most significant interaction was between rate and length of stroke. An increase in stroke rate from one to two cycles per second at a stroke length of 2 mm produced an increase in cutting for both the Heliosonic and Shaper files. However, at the longer stroke length of 4 mm, the same increase in rate resulted in a decrease in cutting for the Shaper files. Therefore, it is suggested that operators should press the file against the canal wall and move it slowly to maximize cutting.
Detection of epidermal growth factor receptor in inflammatory periapical lesions
Authors: LIN L. M. , WANG S.‐L. , WU‐WANG C. , CHANG K.‐M. , LEUNG C.
Published: September 2007

Epithelial cell proliferation is often observed in periapical lesions of endodontic origin. The mechanisms which stimulate the epithelial cell rests of Malassez to proliferate are not understood fully. Fifteen inflammatory periapical lesions (10 granulomas and five cysts) obtained from periapical surgery and six additional periapical lesions (four granulomas and two cysts) collected from extracted teeth were examined using immunohistochemical staining and 125I‐EGF (epidermal growth factor) binding assay to detect the presence of epidermal growth factor receptor. The results indicated that the periapical lesions without epithelial cell proliferation had a weak immunoperoxidase staining or low specific binding of i25I‐EGF. In contrast, the periapical lesions with epithelial cell proliferation and cyst formation exhibited a strong immunoperoxidase staining in the epithelial cells or high specific binding of 125I‐EGF.
Phantom tooth pain: a diagnosis of exclusion
Authors: BATTRUM D. E. , GUTMANN J. L.
Published: September 2007

This case report addresses the difficult diagnosis of phantom tooth pain (PTP). This is a syndrome of persistent pain in the teeth and oral structures following pulp extirpation, extraction, or rarely, an inferior alveolar nerve block. The incidence of this often misdiagnosed condition is estimated to be 3% of the population undergoing pulp extirpation, and is similar to phantom limb pain. The diagnosis of PTP is discussed here as a diagnosis of exclusion, after numerous interventions. Various treatment modalities are outlined and the use of non‐traditional pharmacological approaches for pain reduction are discussed.
Periradicular curettage
Authors: LIN L. M. , GAENGLER P. , LANGELAND K.
Published: September 2007

Periradicular curettage is a part of the treatment procedure of periradicular surgery. Its main purpose is to remove pathological periradicular tissues for visibility and accessibility to facilitate the treatment of the apical root canal system, or sometimes for the removal of harmful foreign materials present in the periradicular area. Inflammatory periradicular lesions (granuloma and cysts) are the responses of the periradicular tissues to irritants from the root canal and not from the periradicular area unless medicaments and/or filling materials have been forced through the apical foramina or perforations into the periodontium. Histologically, the inflammatory periradicular lesion is similar to healing granulation tissue, which is composed of cells which have natural and specific immunological defence capability and cooperate by means of cytokines to amplify the protective mechanisms of the host. Accordingly, it is not necessary to completely curette out all the inflamed periradicular tissues during surgery, since this granulation‐like tissue will be incorporated into the new granulation tissue as part of the healing process. To control the source of irritants in the root canal is far more important than to remove all periradicular tissues affected by the irritants. The successful removal of all irritants from the root canal system results in resolution of pulpally induced periradicular lesions. In the case where the periradicular lesion is caused by endodontic instruments or cytotoxic filling materials placed in the periradicular tissues, removal of these foreign objects is required for resolution of the lesion.
Variations in the susceptibilities of components of the endodontic microflora to biomechanical procedures
Authors: GOMES B. P. F. A. , LILLEY J. D. , DRUCKER D. B.
Published: September 2007

The role of the endodontic micoflora in pulpal disease and in endodontic treatment failures is well established. Thus the need for effective microbial control is one of the important justifications for biomechanical procedures. However the efficacy of this stage of treatment is dependent upon the vulnerability of the involved species, which may not be uniform. The aim of this study was to investigate variations in the susceptibilities of members of the root canal microflora to routine biomechanical procedures. Forty‐two root canals were investigated microbiologically. Samples were collected before and after instrumentation and the bacterial findings were compared. In 15 cases of‘primary’root canal therapy, despite changes in the population size, no significant change in the species composition of the microflora was observed. However in 27 cases secondary’treatment, a decrease in the number of isolations of Peptostreptococcus spp. was found (P= 0.008). When all 42 cases were considered together, significant decreases were found between first and second samples for anaerobes (P= 0.0117) and for Grampositive species (P= 0.008), especially Peptostreptococcus spp. (P= 0.02). It was therefore concluded that certain species are more resistant to the biomechanical procedures than others.
An in vitro study of the coronal leakage of two root canal sealers using an obligate anaerobe microbial marker
Authors: CHAILERTVANITKUL P. , SAUNDERS W. P. , MACKENZIE D. , WEETMAN D. A.
Published: September 2007

The aim of this in vitro study was to investigate the coronal leakage of obligate anaerobes into root canals obturated with lateral condensation of cold guttapercha with two root canal sealers. Sixty extracted human teeth with straight, single root canals were prepared using the modified double‐flared technique with balanced force under copious irrigation until the master apical file was size 40. The teeth were divided randomly into experimental groups (40 teeth) and control groups (20 teeth). In the experimental groups, 20 teeth were obturated with lateral condensation of cold gutta‐percha and AH26 sealer and 20 teeth were obturated with the same technique using TubliSeal EWT sealer. In the control groups, 10 teeth were obturated with the same technique either with AH26 or TubliSeal EWT sealer. These teeth were completely sealed to serve as negative controls. The remaining 10 teeth were not obturated and served as positive controls. The root surface of each tooth was sealed with nail varnish except the apical 2 mm. The coronal part of each root canal was sealed with the cut end of polypropylene tube and placed in a glass bottle containing sterile Fastidious Anaerobe Broth (FAB). Aliquots of 0.5 mL of FAB were injected into the polypropylene tube and the model system was centrifuged at 168 g. An inoculum of Fusobacterium nucleatum in FAB was placed in each coronal chamber at 7‐day intervals and daily observations were made for bacterial growth in the apical reservoir for 12 weeks. All positive control teeth showed bacterial leakage within a week, while the negative control teeth remained uncon‐taminated throughout the test period. All the experimental teeth exhibited leakage of bacterial metabolites within 12 weeks, ranging from 1 to 12 weeks. The mean time for complete leakage in the AH26 and the TubliSeal EWT groups was 8.4 and 8.2 weeks respectively. There was no statistically significant difference (P > 0.05) in leakage between the AH26 and the TubliSeal EWT groups.
Microleakage of Cavit, CavitW, CavitG and IRM by impedance spectroscopy
Authors: JACQUOT B. M. , PANIGHI M. M. , STEINMETZ P. , G'SELL C.
Published: September 2007

The aim of this study was to quantify the sealing ability of four temporary filling materials over 9 days using a new electrochemical technique. Fifty‐two extracted human maxillary bicuspids were selected and prepared for the measurements. They were divided into four groups of 12 teeth each, in addition to two positive and two negative controls. After preparation of the endodontic access cavity the sealing ability was registered. After a randomization procedure one group was obturated with IRM, another group with Cavit, a third group with CavitW and the last group with CavitG. The sealability was measured just after obturation (time 0) and after days 1, 2, 3, 4, 7 and 9. The results showed that the IRM group was significantly more watertight than the different Cavit formulations. Throughout the experiment no significant difference was noticed between the Cavit and CavitW groups (P < 0.05). The CavitG group was significantly less watertight throughout the measurements (P < 0.05).
Rigidity and retention of carbon fibre versus stainless steel root canal posts
Authors: PURTON D. G. , LOVE R. M.
Published: September 2007

Two of the main requirements of a root canal post are that it is rigid so as to resist flexing under functional load, and that it is well retained in the root. This study compared these properties in two different 1‐mm diameter root canal posts–smooth carbon fibre posts (Endopost) and serrated stainless steel posts (Parapost). Ten posts of each type were tested for rigidity in a three‐point bend test. Ten posts of each type were cemented with resin cement into the roots of endodontically treated, extracted teeth. The tensile force required to remove the posts was recorded. The Paraposts proved to be significantly more rigid under load (P < 0.001) and significantly more strongly retained in the tooth roots (P < 0.005). The Parapost appears to be a mechanically superior post for the restoration of root‐filled teeth with narrow diameter root canals.
Resumed tooth development following avulsion of a permanent central incisor
Authors: GREER J. M. , MOULE A. J. , GREER P. J.
Published: September 2007

A case is presented in which an upper right central incisor was avulsed because of trauma at age six. At the time of trauma it was suspected that the pulp had remained in the socket although the tooth had been lost. No attempt was made to treat the socket, remove the pulp, or replant the tooth. Follow‐up radiography showed that, despite initial apparent complete loss of the calcified portion of the tooth, root development proceeded to completion.
Calcium ion diffusion from calcium hydroxide‐containing materials in endodontically‐treated teeth: An in vitro study
Authors: REHMAN K. , SAUNDERS W. P. , FOYE R. H. , SHARKEY S. W.
Published: September 2007

The aim of this in vitro study was to determine the amount and duration of diffusion of calcium ions from both a calcium hydroxide‐containing root canal sealer and an intracanal medicament, through the apical foramen and the dentinal tubules of endodontically‐treated teeth. The root canals of 88 freshly extracted single‐rooted teeth were prepared using the modified double flared, balanced force technique with patency filing. The teeth were divided into four test groups of 20 teeth each and a control group of eight teeth. One group was dressed with a non‐setting calcium hydroxide while the other was obturated using cold lateral condensation of gutta‐percha with a calcium hydroxide‐containing sealer. An artificial root defect was created in the apical third of the root of the teeth in the other two groups and the root canals were either dressed or obturated in the same way as the first two groups. All groups were incubated at 37°C and were sampled for calcium diffusion after 1, 2 and 3 days and 1,2,3,4 and 8 weeks. There was statistically significantly more calcium diffusion with the non‐setting groups compared with the sealer groups (P < 0.05). There was more calcium ion diffusion from teeth with a patent apical foramen than those with an artificial resorptive root defect (P< 0.05).
The antimicrobial activity of endodontic sealers to anaerobic bacteria
Authors: ABDULKADER A. , DUGUID R. , SAUNDERS E. M.
Published: September 2007

The effect of five root canal sealers and two root canal dressing materials on the growth of three anaerobic bacteria associated with endodontic infections was determined using the agar diffusion inhibitory test. Samples of the following endodontic sealers (Apexit, Ketac‐Endo, Roth Sealer, Sealapex and Tubliseal) and root canal dressing materials (Pulpdent and Root‐cal) were incubated for 48 h with the following anaerobic bacteria: Capnocytophaga ochracea, Porphyromonas gingivalis and Peptostreptococcus micros. Statistically significant zones of bacterial growth inhibition for all the bacteria tested were observed in descending order of antimicrobial activity: Roth Sealer, Ketac‐Endo, Tubliseal, Apexit and Sealapex. Root‐cal and Pulpdent also showed statistically significant antimicrobial activity, but only to Capnocytophaga ochracea, not to the other two bacteria tested, with Pulpdent being the least active.
Root‐end cavity preparation using the MicroMega Sonic Retro‐prep Tip™. SEM analysis
Authors: LLOYD A. , JAUNBERZINS A. , DUMMER P. M. H. , BRYANT S.
Published: September 2007

The objective of this laboratory study was to compare root‐end cavities prepared with sonic Retro‐prep tips in a MM 1500 Sonic Air handpiece with those created by burs in a conventional handpiece. A total of 80 single‐rooted extracted human teeth with mature apices and straight canals were included in the study. Four groups of 20 extracted teeth were prepared as follows: I, a 3‐4 mm root‐end resection perpendicular to the long axis of the root, with a size 40 sonic Retro‐prep tip creating an apical cavity 3 mm into root canal system; II, a 45° bevel of the root‐face removing a 3‐4 mm root segment and root‐end preparation as per group I; III, root‐end resection as per group I, with an apical cavity prepared using a size 010 inverted cone bur 3 mm down the long axis of the root; IV, resection as per group II, followed by an apical cavity preparation with a size 010 inverted cone bur 3 mm into the root canal system. The apical root portion and root‐end cavities were replicated and prepared for SEM analysis at × 20 and × 80 magnification. The degree of chipping associated with the margin of the root‐end cavities, as evaluated with a standard grading system, and the incidence of root‐face cracks were noted. Marginal chipping of root‐end cavities prepared using sonic instrumentation was significantly worse than that produced by burs (P<0.001). Perpendicular root‐end resections showed significantly better scores than bevelled root‐end resections (P<0.005). The incidence of root‐face cracking was low with no significant difference between the experimental groups.
Cutting efficiency of Hedstrom, S and U files made of various alloys in filing motion
Authors: SCHÄFER E. , TEPEL J.
Published: September 2007

The cutting efficiency for sizes 25 and 35 stainless steel Hedstrom S and U files from 10 manufacturers, and titanium‐alloy Hedstrom S and U files from five manufacturers, tested for linear (filing) motion under standardized conditions were determined. Special plastic samples having well‐defined abrasive properties were used as the substrate and constant pressure was applied until the instruments were blunt. The depth of the groove achieved by filing was used to measure cutting efficiency. For both sizes there were significant differences in the cutting efficiency of files made by the various manufacturers (P < 0.001). Hedstrom files made of stainless steel, made by VDW, gave the best cutting efficiency for sizes 25 and 35. Overall, under the conditions of this study, Hedstrom files had better cutting efficiency than S or U files. Likewise, stainless steel files provided better cutting efficiency than instruments made of titanium alloys.
Intra‐canal cutting ability of MM 1500 files
Authors: LUMLEY P. J. , HARRINGTON E. , MARQUIS P. M. , WALMSLEY A. D.
Published: September 2007

The aims of this study were to develop a model system capable of monitoring lateral forces during root canal preparation and to measure the cutting ability of files activated by the MM 1500 sonic handpiece. Forces were monitored by a calibrated model system which utilized a combination of spring steel beams fitted with strain gauges, these were interfaced through two strain gauge amplifiers to an x‐y recorder. Single rooted canine teeth (n= 36; 32 experimental, four control) were mounted in a two‐part acrylic mould (which was an integral part of the model system) prior to sectioning horizontally 11 mm from the tooth apex. A 24 full factorial experiment with two replications was performed. Four variables were selected for evaluation, load (50 and 100 g), power (air inlet ring half or fully open), file type (Heliosonic or Shaper) and stroke rate (1 or 2 cycles per second). A new file (size 25) was used for 1 min in each canal with water irrigation. The control group was not instrumented. The cross‐sectional root canal area was measured before and after instrumentation using image analysis and increase in area was used as an indication of cutting ability. The results showed that the increase in load, power and the Shaper file all produced a significant increase in cutting ability (ANOVA, P < 0.001). However, stroke rate was not found to have a significant effect (P > 0.05). None of the interactions between the variables were significant and there was no significant difference in the control group (P > 0.05). In conclusion, this work has developed a model system to monitor lateral forces and has shown that instrument design and operator usage affect dentine removal from a root canal wall.
Comparison of three instrumentation techniques in the preparation of simulated curved root canals
Authors: ZMENER O. , BANEGAS G.
Published: September 2007

Forty‐five acrylic blocks with simulated curved canals were divided into three groups of 15 blocks each. In group 1 the canals were instrumented with ultrasoni‐cally energized K‐files (UEF) using a piezoelectric ultrasonic device. In group 2 the canals were prepared with ProFile 0.04 Taper Series 29 Rotary Instruments (PRI) in conjunction with a low‐speed high torque handpiece. In group 3 (control) the canals were hand instrumented (HI) with conventional K‐type files using a standard push‐pull circumferential technique. The efficiency of these techniques for preparing the simulated canals were compared by measuring the amount of transportation of the prepared canals at different levels from the working length using a double exposure photographic technique. A statistical analysis was used to indicate any significant difference among groups. The results showed that the use of PRI provided well‐centred and more tapered preparations. Conversely, the use of UEF and HI resulted in frequent alteration of the original curvature, showing transportation at different levels from the working length.
The sealing ability of Thermafil obturators assessed by four different microleakage techniques
Authors: PATHOMVANICH S. , EDMUNDS D. H.
Published: September 2007

An in vitro investigation was performed to assess the extent of apical dye leakage in relation to root fillings made by Thermafil obturators and the lateral condensation of gutta‐percha in extracted human teeth under conditions of passive dye penetration, centrifugation, a vacuum technique and an increased air pressure technique. One hundred and twenty‐eight extracted teeth were selected and prepared. The specimens were allocated into eight closely matched experimental groups. Four groups were obturated with Thermafil obturators and four with the lateral condensation technique. Microleakage was assessed after exposing one group of specimens from each of the obturation techniques to each of the four dye penetration systems using India ink as the leakage detector. The teeth were demineralized and cleared prior to examination and the maximum dye penetration for each specimen was recorded. The statistical analysis on transformed data revealed no significant differences between the four microleakage techniques and no differences between the two obturation techniques.
A comparison of stainless steel and nickel‐titanium K‐files in curved root canals
Authors: CHAN A. W. K. , CHEUNG G. S. P.
Published: September 2007

The purpose of this study was to determine the effects of hand instrumentation using traditional stainless steel K‐files and nickel‐titanium K‐files on the final shape of curved root canals. A total of 24 moderately curved canals in the mesial roots in extracted human mandibular first molars were randomly divided into two groups. These were instrumented manually using either stainless steel or nickel‐titanium K‐files with the step‐down technique. The cross‐sectional shape of each canal at three different horizontal levels were captured, before and after instrumentation, into a computer for comparison using image analyser software. Three parameters at each level were evaluated: (i) amount of dentine removed; (ii) least remaining dentine thicknesses on mesial and furcal aspects; and (iii) the amount and direction of canal transportation. The results showed that the two file types removed similar amounts of dentine at all three levels examined. The nickel‐titanium files left a thicker layer of dentine on both the mesial and furcal aspects than stainless steel files. However, the difference was not significant (pooled T‐test, P>0.05). Both types of files transported the centre of the canals but the nickel‐titanium instrument seemed to be safer because of the reduced amount of transportation towards the danger areas.
A scanning electron and confocal laser microscope investigation of tetracycline‐affected human dentine
Authors: LOVE R. M. , CHANDLER N. P.
Published: September 2007

Because of the well reported dental side‐effects of tetracycline administration, the drug should not be administered to children. However, it and its derivatives are often administered over a prolonged period for treatment of acne in young adults. Dental side effects are also noticed in these patients. The aim of this study was to examine with scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) the root dentine of a tooth from a young adult affected by tetracycline therapy. The palatal root of an upper third molar, demonstrating distinct areas of tetracycline staining, was removed from the crown and sectioned longitudinally to produce two samples. The pulp tissue was peeled off the dentine and any remaining non‐mineralized tissues were removed with sodium hypochlorite. One sample was prepared for SEM and the other as a ground section which was examined with a CLSM. It was demonstrated by SEM that the mineralizing front of unaffected dentine was of a normal calcospherite appearance; in contrast, the mineralizing front of the tetracycline‐affected dentine was devoid of calcospherite formation and many surface defects were apparent. In addition, the number of dentinal tubules associated with the defects was reduced. It was shown by CLSM that tetracycline bands were made up of numerous smaller bands and that peritubular dentine not associated with fluorescent bands had incorporated tetracycline. The CLSM examination of the mineralization front of the affected dentine revealed that fluorescence of dentine was restricted to the peritubular dentine. The results confirm that dentine mineralization is affected by systemic tetracycline therapy and that tetracycline can be incorporated into peritubular dentine after mineralization of the primary dentine matrix.
Effectiveness of the Canal Finder and hand instrumentation in removal of gutta‐percha root fillings during root canal retreatment
Authors: IMURA N. , ZUOLO M. L. , FERREIRA M. O. F. , NOVO N. F.
Published: September 2007

The purpose of this study was to quantify the amount of remaining gutta‐percha/sealer on the canal walls when the Canal Finder system, hand instrumentation and a combination of both (hybrid technique) were used to remove these materials. The amount of apically‐extruded debris and the time required for removal were also recorded. Sixty extracted maxillary anterior teeth were prepared using a stepback technique and obturated with gutta‐percha. Reinstrumentation of all groups was done in conjunction with a solvent, chloroform. The teeth were split longitudinally and photographed, and the total area of the root canal and the area of the debris were traced and quantified using a computerized image analysis system. The ratio of remaining obturation material to root canal surface was derived and analysed statistically. Hand instrumentation resulted in less debris remaining than did the other two techniques (P<0.05). The differences in the amount of apically extruded debris were not significant among the techniques (P > 0.05). The hybrid technique required significantly less time for filling material removal. The Canal Finder system alone was not superior to hand instrumentation.
An assessment of microbial coronal leakage in teeth root filled with gutta‐percha and three different sealers
Authors: CHAILERTVANITKUL P. , SAUNDERS W. P. , MACKENZIE D.
Published: September 2007

The aim of this in vitro study was to determine the effect of three different root canal sealers on the bacterial penetration of obturated root canals. Eighty extracted human teeth with straight, single root canals were prepared using the modified double‐flared technique with balanced force under copious irrigation until the master apical file was size 40. The teeth were divided randomly into experimental groups (60 teeth) and control groups (20 teeth). Twenty experimental teeth each were obturated by lateral condensation of cold gutta‐percha with AH26, Apexit or Tubliseal EWT sealer. In the control groups, 10 teeth were obturated using the same technique with AH26, Apexit or Tubliseal EWT sealer. These teeth were completely sealed to serve as negative controls. The remaining 10 teeth were not obturated and served as positive controls. The root surface of each tooth, except the apical 2 mm, was sealed with nail varnish. The coronal part of each root canal was sealed with the cut end of a polypropylene tube and placed in a glass bottle containing sterile Todd‐Hewitt Broth (THB). Aliquots of 0.5 ml of THB were injected into the polypropylene tube and the model system was centrifuged at 168 g. An innoculum of Streptococcus sanguis in THB was added to the tube at 5‐day intervals and daily observations were made for bacterial growth in the apical reservoir for 90 days. AH positive control teeth showed bacterial penetration within 24 h and negative control teeth remained uncontaminated throughout the test period. Leakage through the experimental teeth varied from 7 to 86 days. There was no statistically significant difference (P>0.05) in leakage of the obturated canals between AH26, Apexit and Tubliseal EWT sealers.
Root canal treatment of a root‐fractured incisor tooth with internal resorption: a case report
Authors: ÇALIŞKAN M. K. , TÜRKÜN M.
Published: September 2007

A case is described in which root canal treatment with calcium hydroxide was used successfully to repair a fracture site with internal resorption of the tooth.
Symptomatology and health attitudes of chronic hepatitis B patients in the USA
Authors: Hann H.‐W. , Han S.‐H. , Block T. M. , Harris M. , Maa J.‐F. , Fisher R. T. , Atillasoy E.
Published: September 2007

Summary.  This study was conducted to understand the symptomatology, attitudes, and behaviours of chronic hepatitis B (CHB) patients in the USA. CHB patients enrolled in this study were recruited through multiple methods, including newspaper advertisements. Interviews were conducted in multiple languages, and all participants had a history of CHB infection for at least 6 months. Patients with documented human immunodeficiency virus or hepatitis C virus coinfection were excluded from data analyses, resulting in a total study population of 258 respondents who completed interviews between April and June 2004. The majority of monoinfected patients were male (57%) and non‐Asian (92%, including 52% Caucasian, 32% African American and others). Length of diagnosis was 5.8 years for all participants (9.1‐year Asian and 5.1‐year non‐Asian). Ninety‐five per cent of CHB patients reported symptoms of differing severity in the 12 months prior to the survey. The most common symptoms included fatigue/loss of energy (90%) and loss of appetite (79%). Non‐Asian patients described greater symptomatology, and were more likely than Asians to consider CHB an overriding concern in their daily activities. Patients were treated either currently or previously with interferon (IFN) described greater symptomatology than those treated without IFN. Survey results indicate that CHB patients may have greater symptomatology than recognized. Disease perceptions and treatment attitudes differ between Asian and non‐Asian ethnic groups, with the former appearing to be more accepting and less concerned about the disease. Additional research about CHB symptomatology and health attitudes by ethnicity is needed to ensure that individuals with CHB are educated on the potential health risks and the availability of current treatment options.
Cytokine mRNA expression in hepatitis C virus infection: TH1 predominance in patients with chronic hepatitis C and TH1–TH2 cytokine profile in subjects with self‐limited disease
Authors: Gigi E. , Raptopoulou‐Gigi M. , Kalogeridis A. , Masiou S. , Orphanou E. , Vrettou E. , Lalla T. H. , Sinakos E. , Tsapas V.
Published: September 2007

Summary.  Many determinants of the immune response have been implied in the pathogenesis of chronic hepatitis C. TH1 and TH2 cytokines play a prominent role in viral infections and a dysregulation of these cytokines could account for viral persistence and evolution of chronic disease. To explore a possible TH1 and TH2 cytokine dysregulation resulting in the inability to terminate hepatitis C virus (HCV) infection, we studied TH1 [interferon (IFN)‐γ, interleukin (IL)‐2] and TH2 (IL‐4, IL‐10) mRNA expression of peripheral blood mononuclear cells (PBMC) in response to NS3 HCV antigen stimulation, in 31 untreated patients with chronic hepatitis C and 29 subjects with self‐limited disease. After a 48 h culture of PBMC, total RNA isolation was performed and complementary DNA was prepared by reverse transcription. mRNA levels were quantified by real‐time polymerase chain reaction using a standard curve formed after cloning each cytokine gene and a reference gene using recombinant DNA technology in a specific plasmid vector. In the patients group, mRNA expression of IFN‐γ, IL‐2 and IL‐4 but not IL‐10 was detected, IFN‐γ being the predominant cytokine expressed. All four cytokines were expressed in subjects with self limited disease, however levels of IFN‐γ were lower and a significant higher expression of IL‐10 compared to patients was found. There was a significant correlation between IFN‐γ mRNA expression levels and stage of fibrosis. Our findings show that in chronic hepatitis C, TH1 cytokines predominate and correlate to liver immunopathology. Furthermore, subjects with self‐limited disease, maintain the ability to respond to HCV antigens for a long time after disease resolution.
Towards an understanding of the Of?p star HD 191612: optical spectroscopy
Authors: Howarth Ian D. , Walborn Nolan R. , Lennon Danny J. , Puls Joachim , Nazé Yaël , Annuk K. , Antokhin I. , Bohlender D. , Bond H. , Donati J.-F. , Georgiev L. , Gies D. , Harmer D. , Herrero A. , Kolka I. , McDavid D. , Morel T. , Negueruela I. , Rauw G. , Reig P.
Published: September 2007

We present extensive optical spectroscopy of the early-type magnetic star HD 191612 (O6.5f?pe–O8fp). The Balmer and He i lines show strongly variable emission which is highly reproducible on a well-determined 538-d period. He ii absorptions and metal lines (including many selective emission lines but excluding He iiλ4686 Å emission) are essentially constant in line strength, but are variable in velocity, establishing a double-lined binary orbit with Porb= 1542 d, e= 0.45. We conduct a model-atmosphere analysis of the spectrum, and find that the system is consistent with a ∼O8 giant with a ∼B1 main-sequence secondary. Since the periodic 538-d changes are unrelated to orbital motion, rotational modulation of a magnetically constrained plasma is strongly favoured as the most likely underlying ‘clock’. An upper limit on the equatorial rotation is consistent with this hypothesis, but is too weak to provide a strong constraint.
Timing of Preovulatory LH Surge and Ovulation in Superovulated Sheep are Affected by Follicular Status at Start of the FSH Treatment
Authors: Veiga‐Lopez A , Encinas T , McNeilly AS , Gonzalez‐Bulnes A
Published: September 2007

Contents

The aims of this study were to evaluate the chronology of periovulatory events (oestrus behaviour, LH surge and ovulation) in 16 superovulated Manchega sheep and to determine whether follicular status at start of the FSH supply might affect their occurrence. Mean timing for onset of oestrus behaviour was detected at 28.1 ± 0.7 h after sponge withdrawal; the preovulatory LH surge and ovulation started at 37.2 ± 0.7 h and 65.4 ± 0.7 h after progestagen withdrawal, respectively. The intervals between oestrus, LH surge and ovulation were affected by a high individual variability, which might be the cause for reported decreased efficiency in embryo production. Current results also addressed the role of follicular status at start of the superovulatory treatment on the preovulatory LH surge and the ovulation. The interval LH surge‐ovulation was increased in ewes with a growing dominant follicle at starting the FSH treatment (32.3 ± 0.9 vs 28.6 ± 0.5 h, p < 0.05). The developmental stage of the largest follicle at starting the superovulatory treatment also affected occurrence of LH surge and ovulation; follicles in growing phase advanced the occurrence of the LH surge and ovulation when compared to decreasing follicles (33.0 ± 1.0 vs 43.5 ± 1.1 h, p < 0.05, for LH peak and 60.7 ± 1.1 vs 72.8 ± 1.2 h, p < 0.05, for ovulation). Thus, only ewes with growing follicles ovulated prior to 55 h after sponge withdrawal; conversely, no sheep with decreasing follicles ovulated earlier than 67 h, when an 85.7% of the ewes bearing growing follicles has ovulated at 63 h.
Effect of Aspiration Pressure during Oocyte Harvesting on Oocyte Recovery and in vitro Development of Ovine Oocytes
Authors: Morton KM , Maxwell WMC , Evans G
Published: September 2007

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Oocytes from abattoir‐sourced ovine ovaries were aspirated from 2‐ to 4‐mm follicles using 25, 50 or 100 mmHg pressure and an aspiration pump, or a needle (20‐G) and syringe (2.5 ml) and subjected to in vitro maturation, fertilization and culture to determine the effect of aspiration pressure on the number and quality of oocytes recovered, and early embryonic development. Oocyte recovery rate was similar between groups (range: 57.1–73.1%; p > 0.05). The number and percentage of grade I and II oocytes recovered was reduced for 100 mm (24.5 ± 3.6 and 31.1 ± 6.1%) compared with 25 mm (51.4 ± 7.0 and 60.2 ± 7.8%) and 50 mm pressure (40.8 ± 5.6 and 50.3 ± 4.4%) and a syringe (40.3 ± 12.0 and 45.2 ± 2.1%; p < 0.05). Oocyte cleavage was similar for all groups at 24 (range: 30.9–49.6%) and 48 h post‐insemination (49.7–65.5%), but blastocyst formation (% cleaved oocytes) was lower for oocytes aspirated with 25 mm (37.8%) than 50 (69.2%) or 100 mm (67.2%) pressure, and a syringe (72.0%; p < 0.05). Embryo production efficiency (% of oocytes cultured developing to the blastocyst stage) was higher for oocytes aspirated with 50 mm (45.4%) and 100 mm pressure (43.8%) and a syringe (45.0%) than 25 mm pressure (18.8%; p < 0.05). These results demonstrate that the aspiration of ovine oocytes with an aspiration pressure of 50 mm, or aspiration with a needle and syringe are equally efficacious for the in vitro production of embryos.
Effects of hCG Stimulation on Hepatic Activities of Cytochromes P4502E1 and P4502A in Pubertal Male Pigs
Authors: Zamaratskaia G , Oskam IC , Ropstad E , Tajet H , Dahl E , Andresen Ø
Published: September 2007

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The effects of human chorionic gonadotropin (hCG) stimulation on fat skatole concentrations and hepatic activities of cytochromes P4502E1 (CYP2E1) and P4502A (CYP2A) were studied in Landrace and Duroc breeds of entire male pigs. Pigs were divided into four groups: two control groups of each breed, without hCG stimulation (n = 20 for each breed), and two experimental groups of each breed, with hCG stimulation (n = 18 for each breed). Pigs were slaughtered 3 days after hCG stimulation and activities of CYP2E1 and CYP2A were measured in liver homogenate. Activities of both CYP2E1 and CYP2A were lower in hCG‐stimulated pigs than control pigs for both Landrace (p = 0.005 for CYP2E1, p = 0.016 for CYP2A) and Duroc breeds (p = 0.003 for CYP2E1, p = 0.001 for CYP2A), and skatole concentrations in fat were higher in the hCG‐stimulated pigs of both breeds (p < 0.01). For both control and hCG‐stimulated groups, Duroc pigs had lower skatole concentrations than Landrace pigs (p = 0.001 for both groups). The activity of CYP2E1 did not differ significantly between breeds in either the control group or the experimental group (p = 0.233 for control pigs and p = 0.210 for experimental pigs). However, whereas CYP2A activity did not differ significantly between breeds in the control groups (p = 0.181 for CYP2A), in the hCG‐stimulated groups, CYP2A activity was lower in Duroc pigs than in Landrace (p = 0.011). Based on these findings, we conclude that hCG stimulation can suppress hepatic CYP2E1 and CYP2A activities, probably through an increase in the levels of testicular steroids. Between‐breed variations in skatole levels in fat were not related to the activities of CYP2E1 and CYP2A.
Efficiency Assessment of a Swift Method to Enhance Substandard Viability Ram Ejaculates
Authors: Piperelis SG , Vafiadis D , Boscos CM , Brozos C , Kiossis E , Alexopoulos C
Published: September 2007

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Semen availability in ram semen processing facilities is of great importance for the genetic improvement of sheep. Accordingly, any method that would increase sperm viability in low viability ejaculates could be useful. In this study, the possibility of a glass beads filtration method by estimating the beads total surface provided (TSP) for adhesion of spermatozoa, was evaluated. Initially, two different TSP (102 and 154 cm2) achieved by various sizes of beads (1500, 2000 and 3000 μm) were tested and no significant difference in sperm viability improvement was noticed for the same TSP by different beads (p > 0.05). Next optimization tests were performed in which three different funnels were used for filtration at a standard TSP (154 cm2). The pear‐shaped funnel was found to be the most appropriate for filtration, as semen volume recovery and sperm viability improvement were more pronounced (p < 0.05). Finally, filtration tests were conducted with pear‐shaped funnels with different TSP (102 and 154 cm2) obtained by the aforementioned beads sizes (1500, 2000 and 3000 μm) in equal aliquots. Total surface provided of 102 cm2proved to be the more appropriate for filtration than 154 cm2, as shown by the significant improvement of sperm viability (p < 0.01) and the significantly higher filtrate semen volume (p < 0.05). In conclusion, ram sperm viability improvement by more than 20% of its initial value and semen volume recovery by more than 60%, along with the fact that the total filtration time did not exceed 6 min in any case, suggest that through further development this method could be successfully used during ram semen processing.