bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on human dental plaque 3. Variation of protein constituents among individuals
Authors: Holt Robert L.
Published: April 2006

Abstract. Separate plaque samples (collected from 13 patients who had experienced caries and various degrees of periodontal disease) were each dispersed in 1 ml of distilled water, homogenized and lyophilized. Each lyophilisate was extracted in 1 ml of buffered saline, concentrated and analyzed. Enzyme activity studies revealed amylase in all plaque samples. Lysozyme was present occasionally. By radial immunodiffusion, IgG and IgA were shown to be in plaque extracts of some patients. Immunofluorescence examination of the sediments of individual plaque samples revealed that IgG and IgA occurred frequently. Polyacrylamide gel electrophoresis patterns of the extracts of plaque from different individuals exhibited marked variability despite some zones of similarity. Peptide maps of the dialysable material of the individual plaque extracts were remarkably similar.
In vitro metabolism of testosterone‐4‐14C by canine salivary glands
Authors: Mosadoml Adeyemi , Ofner Peter
Published: April 2006

Testosterone‐4‐14C (2430 pmol, 0.48 μM) was incubated aerobically in 67 mM phosphate buffer pH 7.4 with homogenates and minces of salivary glands from male dogs. Extracted radiosteroids were resolved by thin‐layer chromatography on silica gel, removed and quantitated. Substantially higher NAD+‐dependent 17 β‐hydroxy‐C19‐steroid oxidoreductase activity was found in submaxillary gland homogenates than in similar parotid‐gland preparations. Preliminary evidence is presented that the enzyme activity per unit wet weight of the minced submaxillary gland is decreased in the 2‐week male castrate, in the absence of any recognizable histologic changes in the gland. Testosterone metabolism by canine salivary glands is thus oxidative, contrasting with the reductive 17 β‐hydroxysteroid pathway characteristic of androgen‐dependent organs such as the prostate, and is more extensive than in this accessory sex tissue. Our findings suggest that the canine salivary glands are not target organs for circulating male hormone.
Multiple external‐internal resorptions as late effects of Thorium X (224Ra)
Authors: Reichart Peter , Eckhardt Wolfram , Reznik Gerd
Published: April 2006

Multiple external‐internal resorptions are infrequent and are related to a variety of etiological factors. Thorium X (222Ra) is believed to cause the dental resorptive changes observed in two patients who had received a series of injections each containing 8 to 70 μCi of 222Ra 25 years previously.
Topographical distribution of sulphated glycosaminoglycans in human temporomandibular joint disks
Authors: Kopp Sigvard
Published: April 2006

The distribution of sulphated glycosaminoglycans (GAG's) in the human temporomandibular joint disk and its relationship to sex, age and osteoarthrosis was studied by histochemical methods in autopsy material from 18 individuals. The disks were embedded in paraffin and frontal sections, 5‐7 μ thick, were cut at different levels. Two staining methods were used, toluidine blue at pH 0.5 and alcian blue with different concentrations of MgCl2. The two methods gave comparable results. The sulphated GAG's as represented by metachromatic staining with toluidine blue at pH 0.5 and staining with alcian blue in concentrations of MgCl2 above 0.55‐M were found in the central load‐bearing part of the disks evenly distributed in the medio‐lateral direction. The findings from the alcian blue staining method indicated the presence of sulphated GAG's with characteristics similar to chondroitin/dermatan sulphate and keratan sulphate. The latter finding was most frequent in a surface zone (10‐100 μ) located mainly in the central part of the disks. In macroscopically thin areas of the disks judged as early osteoarthrosis a significant reduction in the staining of sulphated GAG's could be observed. No age or sex differences were found in the distribution of GAG's, either in normal or in osteoarthrotic disks.
A histological study of odontogenic cysts formed following mouse molar tooth transplantation
Authors: Atkinson M. E.
Published: April 2006

Abstract. The enamel organs of subcutaneously transplanted mouse molar teeth undergo cyst formation and present a model for the study of the pathogenesis of developmental odontogenic cysts. Maxillary molars extracted from 10‐day‐old C57B1 mice were grafted subcutaneously into adult mice of the same strain. The grafts were recovered between 2 and 50 days after operation and routinely prepared for histological examination. After initial degeneration, the enamel organ took the form of a squamous epithelium in which after 5 to 6 days squamous hyperplasia took place. Cystic degeneration within the epithelium produced cavities lined with a thick parakeratotic stratified squamous epithelium which resembled the lining of an epidermoid implantation cyst. As the cysts enlarged the lining changed in appearance to a thin squamous non‐keratinized epithelium. Similar features have been described in other experimentally produced cysts and in some odontogenic cysts in humans. Their different morphology may arise from interaction between the surrounding connective tissue with epithelium at different stages of development.
Experimental Allergic Sialoadenitis
Authors: Boss J. H. , Rosenmann E. , Sela J.
Published: April 2006

Abstract The right parotid duct of rats was instilled five to eight times with bovine serum albumin at daily intervals. Acute parotitis developed in non‐sensitized animals, while chronic destructive sialoadenitis ensued in preimmunized rats. The morphological changes were reminiscent of those found in the salivary glands of patients with Sjögren's syndrome.
The effects of feeding a zinc‐deficient diet on taste acuity and tongue epithelium in rats
Authors: CATALANOTTO FRANK A. , NANDA RAVINDRA
Published: April 2006

Abstract Taste preferences, fluid intake and histology of tongue epithelium were studied in rats fed a zinc‐deficient diet and in pair‐fed controls. The results of two‐bottle preference tests demonstrated that zinc‐deficient rats exhibited significantly increased preferences for 1.5 × 10‐1 M HCL and 1.28 × 10‐6 M quinine sulfate as well as a significant increase in relative fluid volume intake. Histologic examination of the tongue epithelium of the zinc‐deficient rats showed a hypercellular prickle cell layer and a marked parakeratosis. The fungiform papillae of the zinc‐deficient rats exhibited acanthosis and mild parakeratosis. However, the pore region of the taste buds did not seem to be covered by the parakeratotic epithelium. The results suggest that the impaired taste observed in zinc‐deficient rats may not be related to blockage of tastants from the pore region.
The influence of traumatic intrusion of primary teeth on their permanent successors in monkeys A macroscopic, polarized light and scanning electron microscopic study
Authors: Thylstrup A. , Andreasen J. O.
Published: April 2006

Abstract Primary maxillary and mandibular central incisors were experimentally intruded on 13 monkeys, in order to examine changes of the enamel in the permanent successors. To study the effect of removal of the displaced tooth, the left primary incisor was extracted 1 h after the trauma, whereas that on the right was left in the jaw. Six weeks later the animals were sacrificed. Macroscopically, circumscribed areas of opacities on labial enamel were noted. The SEM examination showed that non‐affected parts of enamel had reached anatomical form, whereas imbibition studies and microradiographs demonstrated that the maturation process was far from complete. Arrest of enamel maturation was noted as corresponding to the extent of the surface opacity. In the SEM small areas displaying rupture of the surface enamel were seen. No differences were observed either macroscopically or histologically in relation to immediate removal or preservation of the intruded primary incisor.
Focal epithelial hyperplasia in a group of South Africans: Its ultrastructural features
Authors: Van Wyk C. W. , Staz J. , Farman A. G.
Published: April 2006

Election microscopic observation of samples of tissues from lesions diagnosed as focal epithelial hyperplasia revealed the presence of viral particles in six (possibly seven) of 13 cases examined. Viral particles were intranuclear and varied from sparsely scattered to densely packed. A crystalline arrangement was present in one case. The chromatin of affected cells was typically condensed into clumps and thick bands, and the nuclear membrane was usually absent in pronounced cases. The nuclei of the basal and prickle cells were frequently indented and the chromatin peripherally condensed. Numbers of lysosomal‐like organelles were observed in many of these cells. The ballooning epithelial cells with their mitosis‐like aberrations observed with light microscopy consisted of a rim of tonofilmaments and organelles and a homogeneous granular center interspersed with dense areas. It is suggested that the nuclear characteristics and numerous lysosomes observed in basal and prickle cells are cellular changes induced by the viral infection and that the mitosis‐like aberrations represent a bizarre and arrested form of mitosis.
Correlation of histology and ultrastructure in pathology specimens
Authors: Morgan P. R. , Svensson S.‐E. , Heyden G.
Published: April 2006

AbstractA method of preparing frozen sections of surgical specimens for electron microscopy is presented together with a technique by which the histology, enzyme histochemistry and ultrastructure of selected parts of a lesion may be correlated. This procedure involves the embedding of 10–30 μm sections in Epon between Perspex® slides after the removal of which the tissue may be inspected in the light microscope and small areas ringed by a steel marker. These are sawn out and sectioned for ultrastructural examination. The use of this procedure is illustrated first with reference to a zone of hyperplastic, but not dysplastic, vaginal epithelium, parts of which were shown histochemically to contain strong glucose‐6‐phosphate dehydrogenase activity. Electron microscopy of the epithelium‐connective tissue junction in these areas revealed epithelial cytoplasmic processes and an accompanying loss or duplication of the basal lamina. In a second example, accumulations of gutta percha in the epithelium of a dental cyst were shown to be surrounded by a thin layer, the ultrastructure of which resembled previously published electron micrographs of hyalin bodies. It is considered that techniques such as those described may render biopsies of greater potential in research without impairing their diagnostic value.
The effect of ultra‐violet radiation and restricted diet on rat labial mucosa
Authors: Prabhu S. R. , Squier C. A. , Johnson N. W.
Published: April 2006

Abstract The combined effect of ultra‐violet radiation and a restricted diet on oral mucosa was investigated using the labial mucosa of pigmented rats. Twenty‐four rats were divided so that 12 experimental animals received 50% of the average daily diet of the remaining 12 normal controls. After 1 month, the epithelium of the restricted group had thinned to 2/3 of that of the controls. Nine rats from each group were then subjected to daily ultra‐violet irradiation of the labial mucosa, three animals in each group remaining as unirradiated controls. After 1, 4 and 8 weeks irradiation, three experimental and one unirradiated control from each group were sacrificed. Microscopic examination showed that the thickness of the epithelium and the mitotic index increased in both normal and restricted animals at 4 weeks. The increase in thickness was maintained at 8 weeks, but the mitotic index declined in the deficient animals at this time. Evidence of epithelial dysplasia was seen in the normal animals at 4 weeks, and this increased at 8 weeks; such changes were rarely seen in the restricted animals. It thus appears that the extent of ultra‐violet induced dysplasia may be related to the mitotic index, a lower mitotic index implying less dysplasia.
The hematopoietic defect of the jaws: A report of sixteen cases
Authors: Lipani C. S. , Natiella J. R. , Greene G. W.
Published: April 2006

Biopsy of radiolucent lesions of the jaws has resulted in the identification of areas of hematopoiesis usually designated as focal osteoporotic marrow defects. The majority of the cases reported involve the posterior region of the mandible in a previous extraction site.

Pain and swelling are not uncommon. Since the clinical and radiographic symptoms of hematopoietic defects resemble manifestations of other neoplastic and inflammatory diseases, it is important to continue to describe the properties of this interesting entity.
Subjectivity in evaluating oral epithelial dysplasia, carcinoma in situ and initial carcinoma
Authors: Pindborg J. J. , Reibel J. , Holmstrup P.
Published: April 2006

During the 2nd Meeting of the International Association of Oral Pathologists in Amsterdam (1984). an exercise was held to study subjectivity in evaluating oral epithelial dysplasia. A poster with 9 color photomicrographs was presented to be evaluated anonymously by the participants. A total of 72 submitted diagnostic suggestions In Table I these suggestions are given together with the diagnosis by the authors. A surprisingly wide spectrum of diagnostic suggestions was found indicating the need for an internationally accepted set of criteria for oral epithelial dysplasia.
Epithelial mitotic activity during the induction of palatal candidosis in the Wistar rat
Authors: Shakir B. S. , Smith C. J. , Martin M. V.
Published: April 2006

Palatal candidosis was produced in 15 Wistar rats by fitting them with an acrylic appliance that covered the palatal mucosa and simultaneously inoculating this site with Candida albicans 3091 (serotype A). A further 15 rats were fitted with the appliance only. Five animals in each group were killed at 1, 2 and 4 weeks, 4·5h after being injected with vinblastine sulphate, as were 5 normal control animals at the start of the experiment. Palatal mucosa was dissected free, fixed, sectioned and stained prior to counting the number of arrested mitotic figures in the basal epithelial layer and measuring the mean thickness of epithelium. The results were expressed as the number of mitotic figures per 1000 basal cells, per unit length of basement membrane and per square millimetre of epithelial surface. After an initial reduction in thickness, the palatal epithelium in both experimental groups became thicker than that of normal control animals, more markedly so in the animals infected with Candida albicans. Similar patterns of mitotic activity were found regardless of the reference unit used as a basis for the calculations. An initial decrease in both experimental groups was followed by a sharp and significant rise, again being more marked in the animals infected with Candida albicans.
A comparison of oral rinse and imprint sampling techniques for the detection of yeast, coliform and Staphylococcus aureus carriage in the oral cavity
Authors: Samaranayake L. P. , MacFarlane T. W. , Lamey P.‐J. , Ferguson M. M.
Published: April 2006

The sensitivity of the impression culture, the neat rinse culture (NRC) and the concentrated rinse culture (CRC) methods in detecting the oral carriage of yeasts, coliforms and Staphyloccus aureus was estimated in 75 individuals. The recovery of organisms from the imprint cultures of the tongue and the CRC was similar and there was highly significant positive correlation between the two techniques. The CRC was simple to perform, equally sensitive and superior in quantifying yeast, coliform and S. aureux carriage than the imprint culture technique. Hence, it is suggested that the CRC technique be preferentially employed in future investigations to obtain comparable data from different centres.
A radiographic survey of periapical conditions in elderly people in a Swedish county population
Authors: Allard Urban , Palmqvist Sigvard
Published: April 2006

Abstract A random sample of non‐institutionalized people aged 65 years and over in Örebro County, Sweden, were examined radiographically. Periapical conditions and the prevalence and quality of root fillings were evaluated. Approximately every 10th tooth showed radiographic signs of apical periodontitis: more than 1 in 20 teeth not previously root‐filled and more than 1 in 4 root‐filled teeth. Only 28% of the subjects had no tooth with periapical destruction. In all, 18% of the teeth were root‐filled: 27% of maxillary teeth and 11% of mandibular teeth. Periapical destructions were less prevalent in people with many remaining teeth and among married people as compared to the rest of the population. Periapical destructions were more common in subjects from “rest of county” as compared to “densely‐populated areas”. Variations in treatment quality might be one explanation for this difference. The percentage of root fillings classified as “unacceptable” was high (69%).
Vitality testing of teeth with a radiation probe using 133xenon radioisotope
Authors: Trope Martin , Jaggi Jurg , Barnett Frederic , Tronstad Leif
Published: April 2006

Abstract The purpose of this investigation was to determine if the radioisotope 133xenon in saline injected into the periodontium would enter the blood circulation of the pulp and be picked up by means of a radiation probe placed in contact with the crown of the tooth. The maxillary incisors of a young dog were prepared so that there were 3 pairs of teeth with I vital and 1 pulpless tooth in each pair. The tooth to be tested was injected with 0.2 mCi 133xenon in saline by a buccal intraligament injection. A lead shield was placed over the tooth and radiation counts taken every 10 seconds for 15 minutes, using a small cadmium telluride radiation probe. Radiation counts were detected from both vital and pulpless teeth. Pulpless teeth had relatively constant counts for the duration of the experiment (200‐300). In vital teeth the initial counts were much higher (718‐981). A gradual decrease occurred with time and at 6 min the counts of the vital teeth were similar to those of the pulpless teeth and remained so for the rest of the experiment. Thus it was possible to differentiate between vital and pulp‐less teeth: 1) because the initial count was high and above the 200 to 300 counts which generally was found in pulpless teeth; and 2) because of the distinct differences in the clearance curves of the radioisotope from vital and pulpless teeth.
Efficacy and safety tests of six automated devices for root canal instrumentation
Authors: Tronstad Leif , Niemczyk Stephen P.
Published: April 2006

Abstract it was the purpose of this study to lost the efficacy and safety of automated devices for root canal instrumentation. Instruments tested were Giromatic with (a) barbed broaches and Hedstrom files, and (b) RISPI files; Dynatrak with Unifiles; Canal Finder System with K‐files and modified Hedstrom files; Cavi‐Endo with K‐files and diamond‐coated instruments; Endostar 5 with K‐files; and MM sonic 3000 with (a) RISPI files, and (b) Sonic Shapers. Transparent plastic models with simulated root canals of various widths and shapes were used. The canals were enlarged by 0.2 mm at their apices and the instrumentation time‐was recorded. Complications during instrumentation were also recorded. With regard to efficacy, 3 devices stood out among the instruments tested: Giromatic with RISPI files, the Canal Finder System, and the MM Sonic 3000. With the Canal Finder System and the MM Sonic 3000 the tests were completed without complications. It was concluded that automated devices for endodontic treatment are now available that are both efficient and remarkably safe.
Acid etching and composite resin restorations. A culturing and histologic study bacterial penetration
Authors: Mejàre Bertil , Mejàre Ingegerd , Edwardsson Stig
Published: April 2006

Abstract Class‐V cavities were prepared on the buccal surfaces of homologous pairs of premolars in vivo. Composite resin restorations (Adaptic®) were performed using two different acid‐etch techniques. All cavities were unlined. Four cavities were unetched and served as controls. In one series the enamel margins were etched and a non‐composite intermediate resin was used before filling. In the second series the enamel surrounding the composite filling was etched after the insertion of the composite resin and coated with an UV‐light polymerized resin (Nuva‐Seal®). The results were evaluated using both histological and culturing techniques. Neither of the two etching techniques was effective in preventing marginal leakage and in growth of bacteria was found along the cavity walls. The cervical border of the Class‐V cavity is considered a weak link for marginal leakage. Culturing revealed a bacterial flora resembling that of dental plaque.
Book Review
Authors: Baumgarten Harold S.
Published: April 2006

Books reviewed in this article:

P. R. Wheater, H. G. Burkitt, A. Stevens & J. S. Lowe
Effect on periodontal healing of saline irrigation of the tooth socket before replantation
Authors: Matsson Lars , Klinge Björn , Hallström Hadar
Published: April 2006

Abstract The following investigation was designed to study the healing of replanted teeth when the formation of a blood coagulum in the alveolar socket is avoided as much as possible before replantation. Eighteen maxillary incisors from 4 beagle dogs were used. The teeth were extracted and stored dry for 30 min in order to induce a standardized damage to the periodontal ligament cells, and were then replanted and splinted. Nine of the sockets were continuously irrigated with saline to achieve hemostasis before replantation. In 9 sockets a coagulum was allowed to form. After 2 wk the root canals were cleansed and filled with Ca(OH)2 and the splints were removed. Three months later the dogs were sacrified and the premaxillas were removed and processed according to routine histologic methods. Transverse sections were cut and one section at every 500 μm interval was analyzed using light microscopy. Ankylosis was found in 3 teeth replanted in saline‐irrigated sockets, while 8 teeth replanted in untreated sockets were ankylosed. Resorption without ankylosis was found in all teeth, irrespective of type of treatment of the alveolar sockets, but a tendency toward less extensive resorption areas was noted in the teeth replanted in saline‐irrigated sockets. Thus, the present study indicates that continuous irrigation of the alveolar socket with saline before replantation promotes the normal healing of experimentally exarticulated teeth in dogs.
Clinical considerations in the treatment of dens invaginatus
Authors: Rotstein Iian , Stabholz Adam , Heling Iiana , Friedman Shimon
Published: April 2006

Abstract Dens invaginatus is a developmental malformation of teeth which results from abnormal morphodiflerentiation. Such a condition is often associated with pulpal and periapical pathosis, which require treatment. Due to their abnormal anatomical configurations, invaginated teeth present technical difficulties in their clinical management. The treatment modalities available to the clinician include: endodontic therapy, endodontic surgery, combined treatment, or extraction. The treatment of choice should be selected according to specific clinical considerations. This article discusses these clinical considerations and establishes criteria for case selection and treatment planning.
Clinical efficacy of an endodontic antiseptic in a controlled release delivery system
Authors: Tronstad Leif , Barnett Frederic , Londono Alvaro , Drozd Edward , Sloan William , Russo Edward
Published: April 2006

Abstract The purpose of this clinical study was to assess the bacteriological status of the root canal after disinfection with a quaternary ammonium compound in a controlled release delivery system. Fifty‐three teeth with apical periodontitis as evidenced by periapical radiolucencies were used. Under aseptic conditions the root canals were completely instrumented and irrigated with sodium hypochlorite. After the instrumentation, 38 teeth were treated with the quaternary ammonium compound in the controlled release dispenser; 15 teeth were treated with formocresol. Bacteriological samples from the root canals were taken after 7 days using an anaerobic technique. The results indicated that the quaternary ammonium compound in controlled release was as effective as formocresol in obtaining bacteria‐free root canals. The advantages of an antiseptic with a long lasting effect for the elimination of bacteria from the root canal and for the prevention of reinfection were emphasized.
Surgical extrusion of root‐fractured teeth – a follow‐up study of two surgical methods
Authors: Kahnberg Karl‐Erik
Published: April 2006

Abstract Surgical extrusion of teeth with cervical root fractures was carried out in 58 single roots in 53 patients. Two different approaches were used. In Group I a flap operation with apical exposure and bone transplant above the extruded root was performed. In Group II the roots were extruded by careful marginal luxation, and interdental sutures and surgical dressing were used as retention. The mean observation time was 5.5 years in Group I and 2.4 years in Group II. Apical root shortening‐was seen in 17 roots, although in no case was it progressive in nature. Proportionally, apical resorption was seen more frequently in Group I than in Group II. The results encouraged further use of the method, especially with the simplified surgical approach used in Group II.
Endodontic treatment of a canine with a talon cusp
Authors: Tse Chung Ming , Walker Richard T.
Published: April 2006

Abstract This case report describes the endodontic treatment of an isolated canine with a talon cusp. The tooth presented with multiple roots and an associated odontogenic abnormality. This took the form of a dens invaginatus, and may be the first case of its kind to be formally recorded. The successful treatment involved both conventional and surgical endodontic therapy.
Subtraction radiography for the diagnosis of periapical bone lesions
Authors: Kullendorff Boel , Gröndahl Kerstin , Rohlin Madeleine , Henrikson Carl O.
Published: April 2006

Abstract Subtraction and conventional radiography were evaluated for the diagnostic potential to assess periapical bone lesions. The periapical region of dry human mandibles was radio‐graphically examined, subjectively evaluated and measured by 125I absorptiometry before and after the creation of bone defects. Both conventional radiographs and subtraction images made from the conventional radiographs after digitization were interpreted by 10 dentists. Receiver operating characteristic (ROC) analysis technique was used to compare the two techniques. There was a higher diagnostic accuracy using subtraction technique. For a lesion depth corresponding to < 2 mm of compact bone, there was a clear difference between the techniques, but for deeper lesions the conventional technique gained force. The subtraction technique was significantly superior for lesions confined to cancellous bone. The statistical difference in the diagnostic utility of subtraction compared with conventional technique was found to be less for lesions of the cortical bone. Therefore, the conclusion is that subtraction radiography improves the detection of small lesions in the periapical bone area.
The radicular palatal groove – a therapeutic modality
Authors: Friedman Shimon , Goultschin Josef
Published: April 2006

Abstract A radicular palatal groove may be present in about 8.5% of the population, mainly in maxillary lateral incisors. Often this condition predisposes periodontal defects and severe bone destruction, which have been considered untreatable, and extraction has been recommended as a solution. In this report a case is presented of a radicular palatal groove in a maxillary lateral incisor that caused an advanced periodontal defect and pulp necrosis. Like other such cases, this case presented first as an endodontic problem, and was diagnosed by the endodontist. Periodontal surgery failed to resolve the lesion. Filling of the groove by means of amalgam resulted in disappearance of symptoms and closure of the pocket, accompanied by restoration of the lamina dura. The suggested technique was advantageous over previously published treatment modalities, as it effectively eliminated the groove as a pathway of contamination, without loss of tooth substance and without exposure of cut dentin. It is also suitable for treating deep grooves communicating with the root canal.
Ultrasound in endodontics: a quantitative and histological assessment using human teeth
Authors: Biffi João Carlos Gabrielli , Rodrigues Homero Habel
Published: April 2006

Abstract Hand instrumentation of the root canal was compared with ultrasonic instrumentation in 20 maxillary premolars with 2 root canals. The buccal and lingual canals were alternately instrumented by the 2 techniques until they had reached clinically ideal conditions for filling. After mechanical preparation, an attempt was made to evaluate root shape and the enlarging ability of the 2 techniques. For this purpose, a crosswise cut slice approximately 100 μm thick was cut off at the middle level of the root, which permitted comparative quantification of the instrumented area of the buccal and lingual canals. Crosscut serial sections of the remaining parts of the root were obtained for a systematic study of the entire extension of the root canal. It was concluded that the presence of debris inside the root canal depended more on the anatomical variation of the canal than on the technique used. No statistically significant differences in root canal area were evident at the middle third level of the root.
Surgical‐restorative treatment of bleaching‐related external root resorption
Authors: Friedman Shimon
Published: April 2006

Abstract Three teeth in 2 patients were treated after intracoronal bleaching with 30% hydrogen peroxide had resulted in external root resorption. An attempt to treat one tooth by placing an intracoronal dressing with calcium hydroxide had failed. The resorption defects were exposed surgically by reducing and re‐contouring the alveolar crest. The restorations were made during the surgical procedure, with a light‐cured composite in one case and with amalgam in the other, and were of compromised quality due to the difficulty of control. One year follow‐up examinations revealed periodontal complications in both cases, in the form of a further resorption of the alveolar crest and gingival edema. These sequelae suggested that the restoration of bleaching‐related resorption defects should have been a secondary stage, after the surgical exposure of the defects had been completed first. For the purpose of exposing the defects, the level of the alveolar crest should be reduced enough to secure a biological width from the restorations.
Effect of ultrasonic instrumentation on Bacteroides intermedius
Authors: Ahmad Majinah
Published: April 2006

Abstract Two physical mechanisms of ultrasound, cavitation and acoustic streaming, were investigated in an ultrasonic endodontic unit. In addition, the potential of ultrasonic instrumentation for disruption of Bacteroides intermedius was examined at various time intervals. The ultrasonic file could not generate cavitation within the recommended power settings indicated for endodontic purposes. However, there was evidence of acoustic streaming. The latter phenomenon resulted in destruction of 21.6%, 30.4% and 92.9% of test bacteria after 1, 5 and 15 min sonication respectively. It appears that ultrasonic instrumentation of root canals has little bactericidal effect.
The release and diffusion through human coronal dentine in vitro of triamcinolone and demeclocycline from Ledermix® paste
Authors: Abbott Paul Vincent , Hume Wyatt Roderic , Heithersay Geoffrey Sinclair
Published: April 2006

Abstract Crowns from freshly extracted human third molar teeth were used to quantify the release and diffusion of corticosteroid and antibiotic tracer molecules from Ledermix® paste used as an indirect pulp‐capping agent. These molecules readily diffused through dentine and reached a peak rate of diffusion at 2 h. The rate then decreased exponentially with time. The concentrations of the drugs in the dentine were calculated; this showed that a gradient existed from the cavity floor to the pulp space. The data obtained appeared to have clinical relevance and helped explain the therapeutic benefits of this medicament when used as an indirect pulp‐capping agent.
Adhesion of a glass ionomer cement to bleached and unbleached bovine dentin
Authors: Titley K. G. , Torneck C. D. , Smith D. C. , Applebaum N. B.
Published: April 2006

Abstract Cylinders of Fuji Type II glass ionomer restorative cement were bonded to the superficial dentin layer of young bovine incisor teeth that had previously been subjected to 4 different treatments: 1) teeth immersed in 35% hydrogen peroxide for 60 min and etched with 37% phosphoric acid gel for 60 s; 2) teeth immersed in saline for 60 min and etched with 37% phosphoric acid for 60 s; 3) teeth etched with 37% phosphoric acid for 60 s and immersed in 35% hydrogen peroxide for 60 min; or 4) teeth etched with 37% phosphoric acid for 60 s and immersed in saline for 60 min. Specimens were stored in water at 37° for 1 and 7 days, prior to tension and shear testing. A total of 128 teeth were tested: 8 teeth in each group for each day and for each test. Statistical analysis of the results indicated that there was a highly significant reduction in bond strength of the cement when dentin was exposed to hydrogen peroxide as compared with saline. SEM examination of randomly selected fractured test specimens indicated that bond failure was cohesive in nature, suggesting that the hydrogen peroxide treatment adversely affected the setting process of the glass ionomer cement.
Effects of combining Ledermix® and calcium hydroxide pastes on the diffusion of corticosteroid and tetracycline through human tooth roots in vitro
Authors: Abbott Paul Vincent , Hume Wyatt Roderic , Heithersay Geoffrey Sinclair
Published: April 2006

Abstract A 50:50 mixture of a corticosteroid/antibiotic paste and calcium hydroxide has been used clinically as a root canal dressing agent. This study investigated the effect on the release and diffusion of the corticosteroid and antibiotic components of Ledermix® paste when it was mixed with a calcium hydroxide‐methyl cellulose paste. The release rates of the trace molecules were lower when the mixture was used compared with release from Ledermix alone. The results indicated that this combination of materials, when used a long‐term intracanal dressing, was likely to be more effective than Ledermix alone.
Simulated accidental tooth damage during surgical intervention
Authors: Stenvik Arild , Åbyholm Frank , Haanses Hans Reidar , Beyer‐Olsen Eva Margrethe Stermer
Published: April 2006

Abstract Mechanical contact with dental tissues accidentally occurs during jaw surgery. Lesions were inflicted on 10 monkey incisors during experimental surgery that simulated accidental damage to the root. In 6 teeth the lesion penetrated to the pulp. Tissue reactions were observed histologically to evaluate the long‐term iatrogenic processes induced by the procedure. The animals were killed from 315 to 370 d postoperatively. The present material illustrated 3 main categories of long‐term reactions that may be expected from mechanically produced lesions. Maintenance of pulp vitality and formation of reparative hard tissue could be observed either in association with re‐establishment of the periodontal membrane or with ankylosis; pulp necrosis was associated with periapical inflammation and resorption. The proportions of teeth with inflammation and ankylosis were not significantly different when teeth with pulp penetration were compared with teeth without penetration.
Prognosis of permanent teeth in the line of mandibular fractures
Authors: Oikarinen Kyösti , Lahti Jarmo , Raustia Aune M.
Published: April 2006

Abstract A total of 45 mandibular fracture patients with 54 teeth in the fracture line were evaluated retrospectively. One tooth in the fracture line was lost in the accident, 6 were extracted later and 47 could be saved (87%). At the follow‐up examination 38% of the teeth were diagnosed to have pulp necrosis, which was found more frequently in the older patients and in cases in which the time elapsing between the injury and the follow‐up was longer. Pulp necrosis was also more frequent in cases in which the fracture line ran through the apex or dislocation of the fracture parts existed after the injury.
Continuing root formation following apexification treatment
Authors: Yang Shue‐Fen , Yang Zu‐Pyn , Chang Kuo‐Wei
Published: April 2006

Abstract A case report is presented in which continuing root formation occurred in an immature mandibular second premolar after calcium hydroxide apexification treatment. An apical hard tissue barrier was accompanied by a separate disto‐apically growing root 18 months posttreatment. Histologic evaluation of the root revealed immature hard tissue mixed with calcium hydroxide, connective tissue and bone, apically in the original root canal. In the separate new formed part of the root, pulp tissue, odontoblasts, predentin, cementum and an apical foraman could be identified.
In vivo efficacy of various retrofills and of CO2 laser in apical surgery
Authors: Friedman S. , Rotstein I. , Mahamid A.
Published: April 2006

Abstract The purpose of the present study was to radiographically assess the efficacy of various retro filling materials and of the use of CO2 laser in apical surgery. The mandibular premolars of six beagle dogs were infected, resulting in periapical lesions. Apical surgery was performed without root canal treatment. Amalgam with cavity varnish, glass ionomer cement and a light cured composite resin were the retro filling materials used. In half of the material CO2 laser was used on the root surface and the bone, for occlusion of the dentinal tubuli and sterilization. The healing following surgery was observed radiographically for six months. The highest success rate (89%) was found in the roots retro filled with amalgam and varnish, and the lowest (60%) in those retro filled with the composite resin. The difference between these groups was statistically significant. The success rate following retro filling with glass ionomer cement was 69%, and was not significantly different from both the other groups. Under the conditions of this study, the use of CO2 laser during surgery did not affect the treatment results.
Comparison between two ultrasonic units in shaping curved canals in teeth using macroradiography
Authors: Ahmad Majinah
Published: April 2006

Abstract The efficacy of two ultrasonic units in shaping curved canals in teeth were compared. Twenty teeth were instrumented using the Cavi‐Endo unit at a power setting 1 using the technique recommended by the manufacturer. Another group of 20 teeth received similar treatment but were instrumented with the Enac unit. The time taken to instrument each canal was recorded. The pre‐ and post‐instrumented radiographs of the teeth of x 10 magnification were taken using a microfocal technique. The radiographs were subjected to a subtraction technique to result in composite images of the pre‐ and post‐instrumented shapes. The canal shape and the incidence of elbows were evaluated using various measurements taken from the radiographs. The manner the dentine was removed was similar in both groups. All canals exhibited unequal removal along the canal with more dentine being removed at the coronal end. The Enac group exhibited a higher incidence of elbows which occurred further apically than those in the Cavi‐Endo group. There was no significant difference between groups in the following: time of instrumentation, amount of apical and coronal canal enlargement, apical deviation and change in width at the elbow. These findings were no different from those of another study using simulated canals.
Enamel‐dentin crown fractures bonded with various bonding agents
Authors: Munksgaard E. C. , Jorgensen E. H. W. , Andreasen J. O. , Andreasen F. M.
Published: April 2006

Abstract A method is described, by which the fracture strength of bonded, previously fractured incisors can be measured. The study employed incisors from sheep, which could be obtained in suitable numbers and with limited variation in size. The incisors were fractured parallel to the incisal edge. The mean fracture area + SD of central incisors was 8.45 ± 0.89 mm2 and of lateral incisors 6.50 ± 0.64 mm2. The enamel area constituted about 30% of the total fracture area. Acid etching of the enamel and bonding of the fractures with an unfilled resin yielded a fracture strength, which was approximately 38% of the fracture strength of fractured teeth restored with acid etching of enamel, Gluma treatment of dentin and bonding with the unfilled resin. Teeth restored in this way, but using the dentin bonding agent Tenure or Scotchbond2 instead of Gluma, exhibited mean fracture strengths which were not significantly different from that obtained when Gluma was employed as the bonding agent. The mean fracture strength by using one of the three bonding agents in combination with acid etching of enamel was about 8 MPa, which is approximately 50% of the fracture strength of intact teeth.
Reinforcement of bonded crown fractured incisors with porcelain veneers
Authors: Andreasen F. M. , Daugaard‐Jensen J. , Munksgaard E. C.
Published: April 2006

Abstract A method is described by which porcelain laminate veneers are used to reinforce crown‐fractured incisors which have been restored by reattachment of enamel‐dentin fragments using enamel etching and a dentin bonding system. In an experimental model using sheep incisors, it was found that fracture strength equal to that of intact incisors could be achieved by employing this method. This is in contrast to fracture strengths of reattached enamel‐dentin tooth fragments without porcelain laminates which were only 50% of intact incisors. It is suggested that porcelain laminate veneers may be used to supplement fragment bonding, thereby enhancing dental esthetics and function.
Influence of endodontic materials on the bonding of composite resin to dentin
Authors: Macchi R. L , Capurro M. A. , Herrera C. L. , Cebada F. R. , Kohen S.
Published: April 2006

Abstract We assessed the bond strength of a composite resin to dentin that had been in contact with different materials. Flat dentin surfaces in freshly extracted human teeth were covered for 15 min or 48 h with a 1‐mm layer of a variety of materials. The products were mechanically removed and a composite resin cylindrical specimen bonded to the dentin surface using the Prisma universal bond system. After 7 days immersion at 37°C in water, the tensile bond strength was tested. The results were compared with those on dentin surfaces not in contact with any endodontic material. Statistical analysis showed that some materials (Grossmans Cement, IRM, Maisto's slowly resorbable paste) reduced the strength of the bond or even precluded bonding. It is necessary to develop techniques that will eliminate this when restoring endodontically treated teeth.
Plasmacytoma of anterior maxilla mimicking periapical cyst
Authors: Shah N. , Sarkar C.
Published: April 2006

Abstract An unusual case of plasmacytoma mimicking a large periapical cyst in the anterior maxilla is described. Of the involved teeth, 22 was discoloured and had an open, immature apex, a feature strongly suggestive of the lesion being of pulpal origin. The case was treated by a conservative endodontic approach, but failed to show any improvement. Apical surgery comprising complete enucleation of the cystic lesion and extraction of the involved tooth was carried out. The unexpected histopathological finding was a plasmacytoma.
Prognosis of luxated non‐vital maxillary incisors treated with calcium hydroxide and filled with gutta‐percha. A retrospective clinical study
Authors: Cvek Miomir
Published: April 2006

Abstract A material of 885 luxated, non‐vital incisors was evaluated radiographically with respect to healing of periodontal tissues including inflammatory root resorption and occurrence of ankylosis and cervical root fractures. The results were assessed after completion of calcium hydroxide treatment and 4 years after filling of the root canal with gutta‐percha. After treatment with calcium hydroxide, periapical healing occurred in 95% of the teeth. Four years after filling with gutta‐percha, periapical healing was present in 91% of the teeth. In the remaining teeth, recurrent or persistent periapical radiolucency was more frequent in overfilled than adequately filled teeth (P = 0.0001). There was no difference between immature and mature teeth. Inflammatory root resorption healed in 192 of 197 teeth (97%); in 5 teeth it developed into ankylosis. Ankylosis occurred in 13 teeth, all of which were intruded into the alveolar bone at the time of injury. The frequency of cervical root fractures was markedly higher in immature than mature teeth (P>0.0001). Among immature teeth, the frequency of fractures was dependent on the stage of root development [x2= 31,6) and ranged from 77% in teeth with the least to 28% in teeth with the most developed roots. The frequency of fractures was also related to the defects after healing of inflammatory root resorption in the cervical area of the root, significant at P< 0.0001.
Induced periapical lesions in ferret canines: histologic and radiographic evaluation
Authors: Fouad A. F. , Walton R. E. , Rittman B. R.
Published: April 2006

Abstract Ferrets have been utilized in endodontic research to study periapical responses. However, various aspects of induction and healing of periapical pathosis in ferrets are unclear. This study evaluated the radiographic and histopathologic features of induced periapical lesions. Periapical pathosis was consistently–produced in 8 canines of 2 ferrets by extirpating the pulp, leaving the cavities open for a week, then sealing for 12 weeks. The resulting lesions were evaluated radiographically every two weeks. The animals were then killed and the induced lesions evaluated histologically and histobacteriologically. Four untreated canines from 2 other ferrets were used as controls. Results showed that periapical rarefactions were visible in all teeth in the experimental group within 4 weeks. Histologically, the induced lesions consisted principally of a mononuclear inflammatory infiltrate, dominated by macrophages but with numerous lymphocytes. With Brown & Brenn staining, bacteria were demonstrated in the pulp space of teeth in which the lesions were induced and in the apical arborization of the canal system. Only one specimen had bacteria within the periapical lesion.