bluuebunny/crossref_metadata_2025_split huggingface dataset:
The standardized‐taper root canal preparation – Part 5. GT file technique in Small Root canals
Authors: Buchanan L. S. 
Published: March 2003

AbstractAim To describe the shaping of Small Root canals with GT files.Summary Small Roots are lower incisors, two and three canal bicuspids, buccal roots of upper molars, and mesial roots of lower molars. The Shaping Objective instrument for such cases is usually a 0.08 or 0.06 taper GT file. After proper access, pulp tissue should be removed to prevent its compaction and canal blockage. Orifice shaping and smoothing is then achieved with a 35‐0.12 accessory GT File, running at full slow‐speed r.p.m. (5–20K).Crown‐down preparation commences with the 0.10 GT file, followed by the 0.08 and 0.06 tapers as needed. Occasionally, a 20‐0.04 Profile is required to reach length. Files are rotated at 300 r.p.m. with steady, light pressure, and withdrawn frequently for cleaning and inspection. Once one of these files has cut to length, the canal terminus is enlarged to Shaping Objective. If difficulty is encountered, be willing to accept a 0.06 instead of the original 0.08 taper Shaping Objective. If the terminal diameter is 0.2 mm you will have plenty of apical resistance form in a tortuous canal with the 0.06 taper preparation. It is definitely better to end up with a smaller shape than originally planned, than to experience the heartache of separation.Key learning points

Small Root canals should be prepared to a Shaping Objective 0.08 or 0.06 taper.
Pulp tissue should be removed before preparation to prevent compaction and blockage.
Preparation follows in a crown‐down sequence, and may occasionally require the use of small Profiles.
Final apical shaping is easily achieved when root length is reached.
Coronal leakage following three obturation techniques
Authors: Gilbert S. D. , Witherspoon D. E. , Berry C. W. 
Published: March 2003

AbstractAimTo compare coronal bacterial and India ink leakage in three different obturation techniques with the smear layer having been removed.MethodologySeventy extracted single‐rooted teeth were instrumented to an apical preparation size 7 Profile Series 29 (Tulsa Dental Products, Tulsa, OK, USA). The smear layer was removed and 20 teeth were randomly obturated with lateral compaction, 20 teeth with vertical compaction, and 20 teeth with Thermafil (Tulsa Dental Products, Tulsa OK, USA). Ten teeth were used for positive (five teeth) and negative (five teeth) controls. Teeth were stored for 90 days in 100% humidity, then subjected coronally to Proteus vulgaris for 21 days to assess bacterial leakage. Following bacterial challenge, India ink was placed coronally for a further 21 days, then scored according to depth of dye leakage.ResultsVertical compaction leaked significantly less than lateral compaction during bacterial challenge. However, when dye was used there were no significant differences.ConclusionsBacterial leakage and dye leakage demonstrated considerable variability. The use of a dye following bacterial testing may highlight the failure of experimental devices and vertical root fractures, thus avoiding false positive results found with bacterial testing alone.
Effect of calcium hydroxide form and placement on root dentine pH
Authors: Pérez F. , Franchi M. , Péli J. F. 
Published: March 2003

AbstractAimThe aim of this study was to measure variations in dentinal pH following the placement of various forms of calcium hydroxide in either the root canal or the pulp chamber.MethodologyExtracted single‐rooted human teeth were prepared, and the root canals instrumented using a conventional technique. Three cavities were drilled through the root dentine to within 1 mm of the canal wall at the cervical, middle and apical thirds. A total of 125 teeth were randomly divided into five groups; group 1: pure aqueous calcium hydroxide paste (calcium hydroxide/distilled water solution) was placed in the root canal; group 2: the same aqueous calcium hydroxide paste was placed in the pulp chamber; group 3: Hycal®, a new form of calcium hydroxide paste, was placed in the pulp chamber; group 4: calcium hydroxide gutta‐percha points were placed in the root canal; group 5: control group, wet canal (distilled water) without medication. The access cavities and apical ends were sealed, and the teeth were placed in individual vials containing phosphate‐buffered saline, and stored at 37 °C. The pH was measured in the dentinal cavities at 8 h and at 1, 2, 3, 7, 14, and 21 days using a calibrated microelectrode.ResultsAt 8 h and 1, 2, and 3 days, the highest pH values were obtained when the aqueous calcium hydroxide paste was placed in the pulp chamber. At 7 days, the pH had increased in the Hycal® group without being significantly different from the aqueous calcium hydroxide paste placed either in the root canal or in the pulp chamber. At 14 days, Hycal® had the highest pH values (pH 10.65); however, at 21 days no significant difference was noted amongst these first three groups. Control group values ranged from 7.88 to 8.60; the pH created by the calcium hydroxide gutta‐percha points was lower than for the control group. Whatever the product or placement location, cervical pH was similar to middle pH, and greater than apical. However, there was no significant difference between the three when all groups were combined. Overall, aqueous calcium hydroxide paste placed in the pulp chamber provided the highest pH values during the experiment, except at day 14. The aqueous calcium hydroxide paste placed in the root canal or Hycal® had similar values at days 7 and 21.ConclusionsUnder the conditions of this study, an aqueous calcium hydroxide paste placed in the pulp chamber increased dentinal pH more than the other techniques. The pH of dentine is affected by the form of calcium hydroxide used.
Effect of conditioning films and a novel anti‐adherent agent on bacterial adherence to dentine
Authors: Maglad A. , Spratt D. A. , Ng Y‐L. , Gulabivala K. 
Published: March 2003

Aim Adherence of bacteria to dentine is a prerequisite to infection of the root canal system, yet adherence of root canal bacteria to dentine is poorly understood. The aim of this study was to evaluate the effect of conditioning films and anti‐adherent compounds on bacterial adherence to dentine. Methodology Freshly extracted molar teeth were prepared and sectioned to give 225 discs of predetermined dimensions. The discs were allocated to two groups. Group 1 (n = 189) was divided into three subgroups (n = 63) and coated with one of three conditioning agents (artificial saliva, serum, or distilled water) prior to bacterial inoculation. Group 2 discs (n = 36) were treated with either a novel anti‐adherent agent (PC1036, Biocompatibles) (n = 18) or distilled water (n = 18) prior to conditioning with artificial saliva. Monospecies bacterial biofilms were generated on the dentine discs by incubating them in brain heart infusion broth (37 gL−1) containing Streptococcus intermedius (Si), Enterococcus faecalis (Ef) or Lactobacillus fermentum (Lf) (originally isolated from infected root canals). The number of bacteria adhering to the discs in each of the groups was determined using standard serial dilution protocols. Additional discs were prepared under all conditions for scanning electron microscopy. Where appropriate, statistical analysis by one way anova, post hoc Bonferroni, and independent t‐test were used. Results Si adhered significantly better to dentine when conditioned with serum compared with artificial saliva (P = 0.005) or distilled water (P = 0.009). Conversely, Ef adhered significantly better to the control discs (distilled water) compared with serum conditioned discs (P = 0.016). The conditioning films had no effect on the adherence of Lf, which adhered to the dentine discs significantly less (P = 0.001) than either Si or Ef. The anti‐adherent coating significantly reduced the number of Si adhering to the dentine compared with the control (P = 0.012). Conclusion Given the importance of adherence in root canal infection it is conceivable that an anti‐adherent compound, could be used to prevent bacterial recontamination of cavities or the root canal system.
Occlusal loading of EBA and MTA root‐end fillings in a computer‐controlled masticator: a scanning electron microscopic study
Authors: Peters C. I. , Peters O. A. 
Published: March 2003

AbstractAim The aim of this investigation was to assess the marginal adaptation of Super‐EBA (EBA) and Pro Root MTA (MTA) root‐end fillings and the occurrence of microcracks in resected root‐ends of extracted teeth before and after occlusal loading for a five‐year equivalent period in a computer‐controlled masticator.Methodology Twenty‐four molar teeth were root‐filled using lateral condensation and their root‐ends resected. Root‐end cavities were prepared and either EBA or MTA root‐end fillings were placed. All surgical procedures were completed in vitro under an operating microscope. Replicas taken of the root‐end fillings and resected root‐ends were examined using an SEM before and after they were subjected to in vitro chewing cycles in a computer‐controlled chewing simulator for the equivalent of 5 years. Marginal adaptation and integrity of the two root‐end filling materials were evaluated and the presence of microcracks recorded.Results Before loading, a continuous margin was observed with 99.4 ± 2.4% of EBA and 99.2 ± 1.6% of MTA root‐end fillings. After loading, the percentage of continuous margin decreased to 93.1 ± 6.6% and 98.9 ± 3.2% for EBA and MTA, respectively. After occlusal loading, 39.5% of the EBA root‐end fillings were overfilled, whilst 52.6% of the MTA root‐end fillings were underfilled. In total, 12.5% of the resected root‐end surfaces showed microcracking before loading and 25% after occlusal loading.Conclusions Both EBA and MTA displayed excellent marginal adaptation before masticatory loading. After loading, the amount of continuous margin for both root‐end filling materials decreased slightly but was still high.
Non‐surgical root canal treatment of dens invaginatus type 2 in a maxillary lateral incisor
Authors: Tsurumachi T. , Hayashi M. , Takeichi O. 
Published: March 2003

AbstractAim  To describe the clinical management of an unusual dens invaginatus type 2.Summary  A case of dens invaginatus in a maxillary lateral incisor with a periapical lesion is reported. The patient presented with pain and localized swelling. Despite the complex anatomy and diagnosis of dens invaginatus, non‐surgical root canal treatment was performed successfully.Key learning points

Dens invaginatus may be presented in many forms, and the aetiology of this phenomenon is not fully understood.
Due to abnormal anatomical configuration, dens invaginatus presents technical difficulties in its clinical management.
Non‐surgical root canal treatment can be performed successfully.
Vitality status of microorganisms in infected human root dentine
Authors: Weiger R. , De Lucena J. , Decker H. E. , Löst C. 
Published: March 2003

AbstractAim This experimental study was initiated to establish a method for characterizing the vitality status of bacteria in infected human root dentine by differentiating between viable and dead microorganisms.Methodology Twenty‐four root segments of extracted human teeth were infected with either Streptococcus sanguinis or Enterococcus faecalis for 8 weeks. Baseline samples from root dentine (rd) were collected after 4 weeks. These were compared with samples taken at week 8 (control group: n = 12) and with samples collected at week 12 after calcium hydroxide treatment for four weeks (test group: n = 12). After marking viable and dead bacterial cells by two fluorescent dyes, the portion of viable bacteria (PVB) was determined, as well as the number of colony‐forming units (CFU).Results Viable and dead bacteria were identified in all ‘rd’ samples. PVBrd values were lower than PVB values of the bacterial suspension in the root canal lumen. In the control group, PVBrd and CFUrd did not markedly differ at week 4 and at week 8, regardless of the strain used. In the test group, viable but non‐culturable sanguinis streptococci (mean PVBrd = 27%; CFUrd = 0) were detected, despite calcium hydroxide treatment. The viability of E. faecalis was not affected by calcium hydroxide.Conclusions Fluorescence labelling of bacteria in human root dentine gives valuable additional information about their vitality status compared to the parameter CFU. The method may be suitable for following the fate of bacteria in dentinal tubules, for example in the presence of intracanal dressings.
Quantification of cyclin A1 and glyceraldehyde‐3‐phosphate dehydrogenase expression in testicular biopsies of infertile patients by fluorescence real‐time RT‐PCR
Authors: Schrader Mark , Ravnik Stuart , Müller‐Tidow Carsten , Müller Markus , Straub Bernd , Diedrichs Sven , Serve Hubert , Miller Kurt 
Published: March 2003

The objective of this study was to establish a classification of meiotic disorders by detection of glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) and cyclin A1 mRNA in patients presenting with non‐obstructive azoospermia.GAPDH and cyclin A1 expression levels were detected in 37 histologically classified testicular tissue specimens by one‐line RT‐PCR. Levels of cyclin A1 expression (NCyclinA1) were high in tissue specimens with full spermatogenesis [3.519 ± 3.141 (mean ± SD)] but only minimal in those without haploid germ cells. A lack of cyclin A1 expression was seen in most sertoli‐cell‐only syndrome (SCOS) specimens. The criteria for an ideal internal standard were only partially met by GAPDH, as we detected decreased expression in tissue samples with maturation arrest [(268.2 ± 106.2 relative gene expression (mean ± SD)] and SCOS (201.7 ± 95.2) compared to those with normal histological findings (325.1 ± 129.3).It was concluded that the level of cyclin A1 mRNA expression predicts meiotic disorders during spermatogenesis. GAPDH is not an ideal internal standard for specific gene expression in testicular tissue specimens.
Androgen insensitivity and male infertility1
Authors: Hiort O. , Holterhus P.‐M. 
Published: March 2003

SummaryAbnormal human spermatogenesis can be caused by defects in androgen action because of androgen insensitivity. A variety of mutations have been described in the human androgen receptor gene associated with male infertility. These can be attributed to two molecular mechanisms. First, point mutations in the androgen receptor gene cause alterations in the amino acid sequence and, hence, lead to apparently slight changes in the androgen receptor effector mechanisms and mild androgen insensitivity. Secondly, variations in the polymorphic poly glutamine segment within the N‐terminal end of the androgen receptor have been ascribed to correlate with fertility aspects possibly because of modifications of transcriptional regulatory mechanisms. It has been postulated that longer poly glutamine segments are associated with decreased sperm counts. However, the molecular mechanisms that lead to inhibition of spermatogenesis because of a mutated androgen receptor are poorly understood and will need more focus in the future.
Resolution of skeletal muscle inflammation in mdx dystrophic mouse is accompanied by increased immunoglobulin and interferon‐γ production
Authors: Lagrota‐Candido Jussara , Vasconcellos Rita , Cavalcanti Marta , Bozza Marcelo , Savino Wilson , Quirico‐Santos Thereza 
Published: March 2003

Summary.Mdx mouse, the animal model of Duchenne muscular dystrophy, develops an X‐linked recessive inflammatory myopathy with an apparent sustained capacity for muscle regeneration. We analysed whether changes in the skeletal muscle during myonecrosis and regeneration would correlate with functional alterations in peripheral lymphoid tissues. Here we show that during the height of myonecrosis, mdx mice display marked atrophy of peripheral lymph nodes and extensive muscle inflammation. In contrast, enlargement of draining lymph nodes with accumulation of CD4+ CD44+, CD4+ CD25+, CD8+ CD44+ T lymphocytes and type‐2 B cells was consistently observed during amelioration of the muscle lesion. In addition, regeneration of the muscular tissue was accompanied by concomitant increase of immunoglobulin‐secreting cells in regional lymph nodes and bone marrow. Double immunolabelling analysis revealed intense B cell proliferation and formation of germinal centre in the follicles of dystrophic regional lymph nodes. Furthermore, lymph node cells produced large amounts of IFN‐γ but not IL‐4, IL‐6 or IL‐10 after in vitro mitogen stimulation with Concanavalin A. As these alterations occurred mainly during the recovery period, we suggested that local activation of the immune system could be an influence which mitigates the myonecrosis of muscular tissue in the mdx dystrophic mouse.
Chemopreventive effect of celecoxib and expression of cyclooxygenase‐1 and cyclooxygenase‐2 on chemically‐induced rat mammary tumours
Authors: Jang Tae Jung , Jung Ho Guen , Jung Ki Hoon , O Min Ku 
Published: March 2003

Summary.We investigated the chemopreventive effect of celecoxib on 7,12‐dimethylbenz[a]anthracene (DMBA)‐induced rat mammary tumours and also the expression and immunolocalization of cyclooxygenase‐1 (COX‐1) and COX‐2 in the various stages of rat mammary carcinogenesis. Rats were divided into normal control group, DMBA‐control group, 500 p.p.m. celecoxib‐treated group, and 1500 p.p.m. celecoxib‐treated group. Both incidence and multiplicity values of tumour for rats treated with celecoxib were less than those in rats of the DMBA‐control group. The level of prostaglandin E2 was higher in tumours of the DMBA‐control and both celecoxib‐treated groups compared to normal mammary glands of each group. In Western blot analysis, all tumours of the DMBA‐control group expressed COX‐1, whereas normal mammary glands showed insignificant expression. COX‐2 expression was observed in 67% of the DMBA‐control group and 20% of both celecoxib‐treated groups and was absent in normal mammary glands. COX‐1 protein was localized in the nuclear membrane and cytoplasm of epithelial tumour cells abutting on glandular lumen, stromal cells, and endothelial cells. COX‐2 protein was detected in the perinuclear cytoplasm of tumour cells bordering on glandular lumen and surrounding stroma, stromal cells, and vascular smooth muscle. In the DMBA‐control group, invasive carcinoma cells showed higher positive immunoreactivity of COX‐2 than carcinomas in situ and atypical tumours. Tumours displayed an increased number of mast‐like cells with COX‐2 expression in comparison to carcinomas in situ. Our results suggest that COX‐1 and COX‐2 expression in tumour cells and stromal cells play an important role in the various stages of DMBA‐induced rat mammary carcinogenesis. In addition, we reconfirm that celecoxib reduces the growth of DMBA‐induced rat mammary tumours.
A survey of cases of cancrum oris seen in Ile‐Ife, Nigeria
Authors: Oginni F.O. , Oginni A.O. , Ugboko V.L. , Otuyemi O.D. 
Published: March 2003

Summary.
Aim. To review the records of child patients with cancrum oris who presented at a teaching hospital in Nigeria. Setting. Obafemi Awolowo University Teaching Hospital, Ile‐Ife, Nigeria. Sample and methods. The study was carried out through review of records of child patients diagnosed as having cancrum oris or post‐cancrum oris defects between 1982 and 1996. Age, gender, site distribution, treatment and its outcome were recorded. Results. One hundred and forty‐two cases were diagnosed during the study period. Mean age was 4·65 years (range 2–16 years). The maxillary quadrants were affected more often than the mandibular. Seventeen patients completed treatment satisfactorily, but 55 failed to do so. All patients had evidence of malnutrition. Conclusions. The findings of this and other studies demonstrate the need for major initiatives to address the underlying causes of cancrum oris and to promote the utilization of health care.
Rare benign tumours of oral cavity – capillary haemangioma of palatal mucosa: a case report
Authors: Açikgözsurname Aydan , Sakallioglu Umur , Özdamar Sükrü , Uysal Ata 
Published: March 2003

Haemangiomas are benign tumours composed of blood vessels, they are probably developmental rather than neoplastic in origin. Haemangiomas are often present at birth but may become more apparent during life. The tumours appear as a flat or raised reddish‐blue lesions and are generally solitary. They are occasionally seen on the palatal mucosa.Haemangiomas are classified on the basis of their histological appearance as capillary, mixed, cavernous or a sclerosing variety that tends to undergo fibrosis. Their differential clinical diagnosis is based on appearance. The tumours may be slowly progressive, involving extensive portions of the superficial and deep blood vessels. Function may be affected where development of the lesion is extra‐invasive. Colour change on pressure is a common finding with return to the original colour on withdrawal of pressure.The case presented here was referred because of swelling and recurrent periodontal bleeding. The lesion was diagnosed as a capillary haemangioma through histopathology.Although different therapeutic procedures have been reported, in this case surgical excision was carried out under general anaesthesia following hospitalization.Despite their benign origins and behaviour, haemangiomas in the region of oral cavity are always of clinical importance to the dental profession and require appropriate clinical management. Dental practitioners and oral surgeons need to be aware of these lesions because they may pose serious bleeding risks.
A prospective study of factors affecting survival of replanted permanent incisors in children
Authors: Boyd D.H. , Kinirons M.J. , Gregg T.A. 
Published: March 2003

Objective. To examine the factors associated with the onset of resorption in replanted avulsed permanent incisor teeth and to demonstrate their patterns of survival free of resorption. Setting. Department of Paediatric Dentistry, Belfast. Design. Prospective recording of the timing of the injury and of replantation, the storage media, the degree of root development and contamination, and the completion of root treatment. Clinical and radiographic reviews at 3‐month intervals. Root resorption classified as replacement and inflammatory. Logistic regression and survival curves with freedom from resorption as outcomes. Results. In 50 avulsed incisors in children aged 6–16 years the best predictor of overall resorption was total time of dryness, and that for replacement resorption was total extra‐oral time. The timing of detection of resorption varied from 102 days to 997 days. Conclusion. Both total extra‐oral time and time stored dry are important factors for the onset of resorption in replanted avulsed teeth in children.
Correction of anterior dental crossbite with composite as an inclined plane
Authors: Sari S. , Gokalp H. , Aras S. 
Published: March 2003

Objective. The purpose of this study was to evaluate a passive method to correct anterior crossbite of only one incisor by constructing a composite inclined plane. Sample and Method. A total of 35 children aged 7–11 with a crossbite of only one incisor tooth were selected for this study. An inclined composite block 3–4 mm in size and 45 degrees to the longitudinal axis of the tooth, was constructed on the incisal edges of the related mandibular incisors. The occlusion was checked so that the only contact between both arches was at the level of these incisors. Results. At the end of one week, 33 cases of crossbite were corrected by this method. Of the two cases which were not corrected one had a deep overbite and the second had a rotated incisor together with crossbite. Conclusion. The present results show that, a composite inclined plane is a useful technique to correct anterior crossbite of only one incisor tooth.