bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scanning electron microscopic study of the apical dentine surfaces lased with Nd: YAG laser following apicectomy and retrofill
Authors: STABHOLZ A. , KHAYAT A. , WEEKS D. A. , NEEV J. , TORABINEJAD M. 
Published: September 2007

SummaryThe purpose of this investigation was to study the effects of a Nd:YAG laser on the5 cut surface of teeth using scanning electron microscopy (SEM). Eighteen single‐rooted teeth were cleaned, shaped, and obturated with gutta‐percha and root canal sealer. The apical 3 mm of each tooth were resected with a diamond fissure bur, and the teeth were randomly divided into two groups of nine teeth each. The resected surface of each root in one group was lased twice. The duration of lasing and the number of pulses were recorded for each tooth. The teeth were air dried, mounted on stubs, sputter‐coated with gold‐palladium and examined under SEM. Application of the Nd:YAG laser caused melting of apical dentine surfaces. The melted material resembled the appearance of glazed interconnected droplets. Resolidification and recrystal‐ization of the melted areas appeared to be incomplete and discontinuous. Some areas between the glazed regions appeared similar to those of non‐lased apical dentine resected root surfaces.
A comparison in vitro of two ultrasonic root canal preparation techniques
Authors: YAP S.Y.S. , STOCK C. J. R. 
Published: September 2007

SummaryTwo ultrasonic techniques were compared for their ability to clean and shape root canals in extracted human teeth. One technique was recommended by the manufacturer (Cavi‐Endo, Dentsply), while the other was a modification by the authors of the stepdown technique. Mesiobuccal root canals of molars were instrumented using these techniques, after which a silicone impression material was injected into the prepared canals. The roots were then split longitudinally and one half was stained for debris scoring while the silicone impressions were assessed for shape. The results showed that the modified technique produced significantly cleaner canals than the recommended technique. The shaping ability of both techniques was difficult to evaluate because of the complex morphology of molar root canals. The final shape of the prepared canal depended more on the initial shape than on the instrumentation technique.
Pulp responses to two strains of bacteria isolated from human carious dentine (L. plantarum) (NCTC 1406) and S. mutans (NCTC 10919)
Authors: PATERSON R. C. , WATTS A. 
Published: September 2007

SummaryA series of studies has been conducted in which mono‐infected gnotobiotic rats were used to study the responses of the dental pulp to micro‐organisms isolated from carious lesions in dentine. In this study pulp responses to L. plantarum (formerly odontolyticus) (NCTC 1406) in pure culture and in combination with S. mulans (NCTC 1O919) are reported. The incidence of inflammation/necrosis/dentine bridge formation observed in animals monoinfected with L. plantarum was similar to that reported in previous germ‐free studies. There was a greater incidence of dentine bridge formation in rats monoinfected with L. plantarum compared with those monoinfected with S. mutans. When the two organisms were combined, periapical inflammation was observed in 14%of the teeth examined after 28 days, but there was no significant difference in the incidence of dentine bridge formation. Considerable variation in the density of staining of the two microorganisms in histological sections was observed.
Pulp response to, and cariogenicity of, a further strain of Streptococus mutans (NCTC 10832)
Authors: WATTS A. , PATERSON R.C. 
Published: September 2007

SummaryThe pulpal response to and cariogenicity of a third strain of Streptococcus mutans, namely S. mutans (NCTC 10S32), was studied in monoinfected gnotobiotic rats of the Fischer strain using the techniques described previously by the present authors. Unlike S. mutans (NCTC 10449 and 10919), S. mutans (NCTC 10832) was associated with the presence of inflammatory cell infiltrates in the coronal pulp of a small number of teeth and extensive periapical inflammation 28 days after the creation of untreated pulpal exposures. S. mutans (NCTC 10832) was associated with the presence of extensive pulpal necrosis and reduced dentine bridge formation. These changes were similar to those noted with the other two strains of S. mutans. S. mutans (NCTC 10832) was non‐cariogenic in monoinfected gnotobiotic rats of the Fischer strain.
Garré's osteomylitis: a case report
Authors: FERREIRA B. A. , BARBOSA A. L. B. 
Published: September 2007

SummaryThis is a case report of Garré's osteomyelitis caused by infection from a lower left molar which was successfully managed by root treatment following several unsuccessful attempts with antibiotic therapy alone. After 18 months there was complete resolution ofthe bony lesion.
Bacterial invasion of non‐exposed dental pulp
Authors: HOSHINO E. , ANDO N. , SATO M. , KOTA K. 
Published: September 2007

SummaryAnaerobic procedures were adopted to demonstrate the early bacterial invasion of non‐exposed dental pulps, and to isolate and identify the bacteria. Of 19 freshly extracted teeth which originally exhibited deep dentinal lesions, clinical examination and electric pulp testing showed that nine of them had no pulpal exposure. Thus the pulps of these teeth were covered by clinically sound dentine beneath the carious lesion. Bacteria were found to have invaded the pulps of six of these nine teeth. The predominant bacteria were obligate anaerobes belonging to the genera Eubacleriiim, Propionibacterium and Actinomyces. Other obligate anaerobes were Lactobacilhis, Peptostreptococcus, Veillonella and Streptococcus. The bacterial composition resembled that of the deep layers of dentinal lesions described previously, suggesting that the bacteria isolated in this study had passed through some individual dentinal tubules, to invade the dental pulp.
Influence of surgical treatment of periapical lesions on serum and blood levels of inflammatory mediators
Authors: MARTON I. J. , KISS C. 
Published: September 2007

SummaryChanges in the serum levels of immunoglobulin IgA, IgG, IgM, positive acute phase proteins and complement activity, as well as the lymphocyte subpopulations and the neutrophil leucocyte‐related chemiluminescence in the blood of patients with apical granuloma as related to endodontic and surgical treatment were investigated. Measurements were performed on admission, and 7 days and 3 months after the treatment. Elevated IgM concentration, positive acute‐phase protein levels and spontaneous whole‐blood chemiluminescence were noted at admission. However, a significant decrease in the serum level of each of the six investigated acute‐phase proteins, and in the spontaneous chemiluminescence of blood was observed during the 3‐month follow‐up period. The significant increase in serum complement activity following therapy suggests that complement fixation might have occurred in these patients. A significant increase in the ratio of early sheep erythrocyte rosette‐forming lymphocytes was also observed. The results of this study provide evidence for complete recovery after elimination of local inflammation by proper endodontic treatment and apicectomy in patients with apical granuloma.
The radiographic incidence of multiple roots and canals in human mandibular premolars
Authors: SERMAN N. J. , HASSELGREN G. 
Published: September 2007

SummaryThe aim of this study was to Investigate the incidence in mandibular premolars of multiple roots and root canals that could be demonstrated radiographically. The images of mandibular premolar teeth as seen on intra‐oral full‐mouth radiographic surveys (547) taken with the paralleling technique were examined. In 99 patients (18.1%) there was at least one premolar tooth with either divided canals or roots. First premolars were involved in 15.7% of patients, and second premolars in 7%.
A comparison of the dentine‐removing characteristics of two endosonic units
Authors: GULABIVALA K. , BRIGGS P. F. A. , SETCHELL D. J. 
Published: September 2007

SummaryThe purpose of this study was to compare the dentine‐removing characteristics of size 25 K‐files activated by the Cavi‐Endo and Piezon‐Endo units. The influence of power‐setting, direction of file oscillation, interfacial force and operator‐assisted movement were studied. Filing was performed on flat surfaces of dentine and impressions of the instrumented surfaces revealed characteristic patterns of dentine removal corresponding to the area of contact with the file which was quantified using a Reflex microscope.Differences in dentine removal as affected by the power output of the two systems were only apparent when the maximum power‐setting on the Cavi‐Endo was compared with the maximum recommended for root canal preparation on the Piezon‐Endo. The Cavi‐Endo removed significantly more dentine than the Piezon‐Endo. When operator‐assisted movement of the file was superimposed, both systems removed significantly more dentine than without assisted filing. However, the Piezon‐Endo now removed significantly more dentine than the Cavi‐Endo. This difference was more apparent when the file oscillated perpendicular to the dentine surface, compared with oscillation parallel to the substrate. An increase in the interfacial force from 30 g to 60 g resulted in a greater reduction in dentine removal by the Cavi‐Endo compared with the Piezon‐Endo. Thus, at a 30 g interfacial force there were insignificant differences between the endosonic units but at 60 g, the Piezon‐Endo removed significantly more dentine than the Cavi‐Endo.The dentine‐removing characteristics of the two endosonic units tested are very different under certain conditions. These findings may have important clinical implications.
Adaptation of injected thermoplasticized gutta‐percha in the absence of the dentinal smear layer
Authors: GUTMANN J. L. 
Published: September 2007

SummaryThe adaptation of thermoplasticized, injected gutta‐percha to prepared dentine devoid of smear layer was examined with SEM. Findings indicate a penetration of gutta‐percha into the patent dentinal tubules with or without root canal sealer. The clinical implications of these findings are discussed.
In vitro release of calcium and hydroxyl ions from two types of calcium hydroxide preparation
Authors: TAMBURIĆ S. D. , VULETA G. M. , OGNJANOVIĆ J. M. 
Published: September 2007

SummaryNon‐setting and setting pastes are the most common forms of calcium hydroxide, used in endodontics. The aim of this study was to investigate the differences in the availability of calcium and hydroxyl ions from some commercial preparations of both types. In vitro released calcium and hydroxyl ions were determined by a potentiometric method, after diffusion through sintered glass.The non‐setting pastes evaluated were Calcipulpe, Calxyl Red, Calxyl Blue and Cinacal; while setting base materials were represented by Dycal, Nu‐Cap and Reolit. The data obtained showed significantly higher availability of calcium and hydroxyl ions from non‐setting pastes, compared with‘alkaline cements’(P>0.05). Great variations in the amount of released ions were also found among samples of the same material.
Neural changes in ulcerative and hyperplastic pulpitis: a transmission electron microscopic study
Authors: PIŞKIN B. , AKTENER B. O. , KARAKIŞI H. 
Published: September 2007

SummaryThe purpose of this study was to examine at ultrastructural level the neural changes in human apical pulps of teeth clinically diagnosed as having ulcerative or hyperplastic pulpitis. Seventeen specimens were prepared from six teeth with ulcerative or hyperplastic pulpitis and four specimens from two sound teeth. After routine procedures the specimens were examined under an electron microscope for changes in the structure of myelinated and unmyelinated nerve fibres. Although the teeth used in this study responded positively to vitality test, the results revealed that moderate to severe degenerative changes occurred in the nerve fibres of the apical pulps of the teeth showing these two diseases.
The use of E‐speed film for root canal length determination
Authors: POWELL‐CULLINGFORD A. W. , FORD T. R. PITT 
Published: September 2007

SummaryThis study compared the use of D‐speed and E‐speed dental X‐ray film for assessing the working length of root canals.Root canal files of varying size (ISO 06, 08, 10 and 15) were placed in the root canals of a maxillary molar and a mandibular molar in a dried skull and mandible. Files were set at various lengths relative to the radiographic apex. The X‐ray projections were kept constant. Exposure settings for the two film types that gave comparable radio‐graphic density were selected. Films were developed manually under standardized conditions. A total of 48 films of each type were examined at various magnifications by four trained examiners for the estimation of distance between the file tip and radiographic apex.There were no differences between examiners in estimating working length. The effect of file size, root and magnification were also not significant. The differences between the film types were not significant (P<0.05).It is concluded that clinicians should use E‐speed film instead of D‐speed film for root canal length measurement, because the exposure time was reduced by over 40% but the quality of the radiographic image was not significantly different.
Management of the resected root end: a clinical review
Authors: GUTMANN J. L. , FORD T. R. PITT 
Published: September 2007

SummaryCareful management of the resected root end during endodontic surgery is critical to the overall success of the case. After resection, the root structure presents with multiple anatomical variations and considerations at both a macroscopic and microscopic level. These include root outline, canal anatomy, dentinal tubule configuration, presence of a smear layer and root canal filling material. Proper assessment of these variables will dictate the best methods for root‐end management, along with the attainment of an anatomically compatible root face for optimal healing of the periradicular tissues.
Factors influencing the success of conventional root canal therapy—a five‐year retrospective study
Authors: SMITH C. S. , SETCHELL D. J. , HARTY F. J. 
Published: September 2007

SummaryThis retrospective study on the outcome of conventional root canal therapy was carried out on patients attending the Eastman Dental Hospital between 1970 and 1982. A minimum follow‐up period of 5 years was required for patients to be included in the survey. The characteristics of the resulting sample group, the techniques for canal preparation and obturation and the obturating materials used were analysed. The type of obturating material used had no demonstrable effect on success rate but sex, age, preoperative vitality and periapical pathology were associated with significantly differing success rates. Technique also influenced success rate; the method of canal preparation and the position of the apical seal relative to the radiographic apex were both found to be significant. The overall success rate was 84.29%, representing 692 of 821 teeth included in the survey.
Determining periodontal ligament (PDL) cell vitality from exarticulated teeth stored in saline or milk using fluorescein diacetate
Authors: PATIL S. , DUMSHA* T. C. , SYDISKIS R. J. 
Published: September 2007

SummaryOne of the key factors for obtaining a favourable long‐term prognosis in avulsed teeth is maintenance of the vitality of the periodontal ligament (PDL) cells. Most studies which have examined PDL cell vitality have used neutral red or trypan blue as stains. However, these stains have certain inherent disadvantages. The purpose of this paper was to (i) evaluate the use of saline and milk as storage media for PDL cells and (ii) determine the value of using fluorescein diacetate (FDA) as a staining medium for vital PDL cells on the root surface of avulsed teeth. Thirty‐two single‐rooted premolars were utilized from patients aged 13 to 28 years. Following atraumatic extraction, the teeth in the experimental groups were air dried for 10 min and then placed in either milk or saline for 120 min. Both control and experimental teeth were subjected to trypsinization procedures, staining with FDA, and haemocytometer readings to determine the number of vital cells. There was no statistically signifi‐cant difference in the number of viable cells on the root surfaces of teeth after 2h of storage in either milk or in saline. Furthermore, staining with FDA provided an excellent method by which to determine PDL cell vitality.
Mechanisms controlling secondary initiation of dentinogenesis: a review
Authors: TZIAFAS D. 
Published: September 2007

SummaryDentinogenesis can be initiated secondarily as an intrinsic ability of the dental pulp to repair, or after interaction of pulp cells with specific exogenous inductive factors. In the present article the basic develop‐mental aspects, highlighting the mechanism by which dentinogenesis is initiated during tooth development, are discussed. Furthermore, clinical and experimental observations concerning the events taking place during secondary initiation of dentine formation, as a part of exposed or non‐exposed pulp tissue repair, or as a result of dentine matrix or other chemical‐pulp cell interactions, are reviewed. Discussion includes hypotheses relating to the crucial biological steps leading to expression of odontoblastic‐like cell phenotype and secondary initiation of dentine histogenesis.
An apical leakage study in the presence and absence of the smear layer
Authors: KARAGÖZ‐KÜçÜKAY I. , BAYIRLI G. 
Published: September 2007

SummaryThe apical seal produced by low‐temperature injection of gutta‐percha, with or without root canal sealer, in the presence or absence of the smear layer was evaluated quantitatively using an electrochemical technique. The root canals of 44 teeth were prepared with the smear layer intact following a final flush of NaOCl (group 1), while the root canals of a further 44 teeth were prepared and the smear layer removed with a final flush with EDTA followed by NaOCl (group 2). Subgroups were obturated using Ultrafil System alone or accompanied by Calciobiotic Root Canal Sealer. Microleakage data was expressed as a percentage of apical leakage evident in each group. Statistical analysis of the results revealed that the groups obturated with Ultrafil alone showed no significant differences in leakage compared with the groups where sealer was used, either when the smear layer had been left intact or removed. (P>0.05). However, comparison of the combined two groups with smear layer present versus the combined two groups with smear layer removed showed a highly significant difference (P<0.01), with the incidence of leakage reduced in the absence of the smear layer.
Changes in patient age and tooth distribution for root canal treatment in a teaching hospital over a 15‐year period
Authors: MANOGUE M. , MARTIN D. M. 
Published: September 2007

SummaryThis study was undertaken to determine the changing pattern of root canal treatment undertaken by undergraduates in a teaching hospital over a period between 1976 and 1990 in terms of the incidence of root canal treatment, noting particularly changes in the types of tooth treated and in the age distribution of patients receiving treatment. It was found that the pattern of provision of root canal treatment has altered in recent years to involve a greater proportion of multi‐rooted posterior teeth. More treatment is also being provided for older patients. The trends are comparable with those that have occurred in general dental practice.
Biological perspectives on the non‐surgical endodonfic management of periradicular pathosis
Authors: MAALOUF E. M. , GUTMANN J. L. 
Published: September 2007

SummaryDifferential radiographic criteria are unreliable for the histological diagnosis of periradicular lesions of pulpal origin. It should not, therefore, be assumed that large lesions or lesions with an opaque border are cystic. Even if cystic, or if strands of epithelium are present, the literature supports repair following the removal of the source of the pathosis. In most cases, the aetiological factors are oral contamination through the root canal or degenerating pulpal tissue. Therefore, the mere surgical removal of lesions of pulpal origin without removing the causes through proper root canal cleaning, shaping and obturation, will not result in the healing of the periradicular tissues. In addition to removing effectively the causative factors, environmental changes in the periradicular tissues caused by the process of canal debridement may inherently aid in the demise of epithelium, when present. The salient issues are discussed in light of thorough debridement of the root canal system, coupled with postulated mechanisms for the resolution of lesions displaying epithelial stands or cavities. Likewise, the role of calcium hydroxide and its potential role in the alteration of the periradicular environment is addressed, with support for the repair of large periradicular lesions without surgical intervention.
Comparison of the quality of obturation following endosonic versus hand instrumentation
Authors: NATTRESS B. R. , YOUNGSON C. C. , MARTIN D. M. , CASSIDY M. 
Published: September 2007

SummaryThis study was undertaken to compare the quality of root canal obturation following preparation by endosonic or hand instrumentation. Forty single‐canal, extracted lower premolar teeth were selected. One group of 20 teeth was prepared using a standard step‐back technique, the other 20 teeth were prepared with an ultrasonic machine. The groups were subdivided, with two operators preparing 10 teeth of each group. The teeth were obturated by a third operator using cold laterally condensed gutta percha. The root apices were then immersed in methylene blue dye for 48 h and the teeth sectioned longitudinally. Image analysis recorded the amount of sealer and void within the obturated canal. The linear distance of dye penetration was measured to provide an indication of apical seal. Examination of the root canal shape resulting from the different preparation techniques used was also undertaken. No significant difference was noted in the percentage of sealer and void present in the root canals obturated after endosonic or hand instrumentation. There was a slightly greater although not significant increase in the degree of linear penetration of dye in canals prepared endosonically. The endosonic technique used in this study appeared to produce a canal preparation of slightly less continuous taper than that obtained with hand preparation.
An In‐vitro evaluation of the influence of canal curvature on the sealing ability of Thermafil
Authors: LEUNG S. F. , GULABIVALA K. 
Published: September 2007

SummaryThe sealing ability of lateral condensation and Thermafil were compared in root canals with curvatures either greater or less than 25 degrees. Forty‐eight canals in roots of extracted human mandibular molar teeth were divided into four groups of 12. The root canals in two groups had curvatures of less than 25° and the remaining two groups had canals with curvatures greater than 25°. Four canals acted as positive and negative controls. All canals were enlarged to accept a size 30 file to the working length and flared using the step‐back technique. Roth's sealer was used in all canals. Lateral condensation and Thermafil obturators thermoplasticized in an open flame were used to obturate two groups each of canals, one group with curvatures greater than 25° and the other less than 25°. After immersion in India ink, the teeth were rendered transparent and the linear penetration of dye measured. It was found that Thermafil sealed significantly better than lateral condensation in canals with curvatures greater than 25° (P < 0.05). However, there were no significant differences between the techniques in the groups with canal curvature less than 25°. There was no significant difference in the performance of each of the techniques when analysed with respect to canal curvature.