bluuebunny/crossref_metadata_2025 huggingface dataset:
Root resorption — etiology, terminology and clinical manifestations
Authors: Tronstad Leif
Published: April 2006

Abstract This paper is an attempt to summarize our knowledge on root resorption from the point of view of clinical relevance and to present a revised terminological system that corresponds to our present understanding of the resorptive processes in teeth. It appears practical to keep the terms inflammatory resorption and replacement resorption. Inflammatory resorption occurs when the predentin or precementum becomes mineralized or, in case of the precementum, is mechanically damaged or scraped off. It is seen on the wall of the root canal (internal resorption) and on the external surface of the root (external resorption or cervical resorption) and it may be transient or progressive. Inflammatory resorption becomes progressive when, in addition to a denuded area of an internal or external root surface, there is additional long–lasting stimulation of the resorbing cells, like sharp edges, increased pressure in the tissue, infection, or certain systemic diseases. Replacement resorption is seen in ankyloscd teeth that have become incorporated in bone. It is not a result of a disease process, but occurs as a “mistake” because the cells involved in the remodeling of bone are not able to distinguish between the dental tissues and bone. Whereas progressive inflammatory resorption today can be treated with a high rate of success, replacement resorption still remains beyond our clincial competence.
Bacteroides spp. in dental root canal infections
Authors: Haapasalo Markus
Published: April 2006

Abstract A summary of a series of bacteriological studies of endodontic infections is presented in this article. The bacteriology of 62 root canal infections was studied with special attention focused on the occurrence, role and taxonomy of Bacteroides spp. All infections except one were mixed infections dominated usually by anaerobic bacteria. Four to 6 different species were present in most canals. Species of the genus Bacteroides were found more frequently than species of any other genus. Seventy‐eight Bacteroides strains were isolated from 45 canals. B. buccae, B. intermedius, B. denticola, B. oris, B. oralis, and B. gingivalis were the most common Bacteroides spp. At the beginning of the treatment 35 of 62 teeth caused acute symptoms. The results indicated that symptoms were a result of the synergistic action of the mixed anaerobic flora. The presence of B. gingivalis, B. endodontalis, and B. buccae was more often related to acute cases than other Bacteroides spp. Black‐pigmented Bacteroides and a new Bacteroides‐like organism, Mitsuokella dentalis, seemed to increase the probability that acute symptoms would persist one week after the beginning of the treatment. However, the treatment result assessed after 4 weeks and after 1 year was not affected by the composition of the mixed anaerobic flora. Calcium hydroxide was the only canal disinfectant used. Its efficacy was proved by a bacteriological sample at the second appointment in 10 cases. All teeth were asymptomatic at the third appointment. The susceptibility of the isolated Bacteroides strains to penicillin G was also studied. Only 2 B. buccae strains and 2 B. denticola strains were resistant at a concentration of 2.4 μg/ml. The patients were randomly divided into 3 groups which received 1) no antibiotics, 2) penicillin V (650 mg × 3) for 7 days, or 3) for 12 weeks. There was no difference between the 3 groups in the healing of the periapical lesion after one year. All patients attended the 1‐year control. Fifty cases showed complete healing, partial healing was obtained in 11 cases and in 1 case no healing was observed.
Periodontal tissue reactions following root canal obturation with an injection‐thermoplasticized gutta‐percha technique
Authors: Molyvdas Ioannis , Zervas Panos , Lambrianidis Theodor , Veis Alexander
Published: April 2006

Abstract The thermoplasticized gutta‐percha obturation technique is a relatively recent development in endodontics. In this study we evaluated the possible effects of heat transmitted to the periodontal tissues when the Obtura root canal filling device was used in dog teeth. Two 8‐month‐old beagle dogs were used; 56 root canals of 36 teeth (maxillary incisors and first, second and third premolars of both jaws) were divided into two groups. In Group A 26 root canals were obturated with the lateral condensation technique, while in Group B 30 root canals were obturated using the Obtura device, without sealer. Observation periods were 1, 3, 7, 28 and 56 days. After routine laboratory procedures, hematoxylin‐eosin stained sections were examined under a light microscope. In this experimental model the thermoplasticized gutta‐percha obturation technique caused a periapical inflammatory reaction at all observation periods. Inflammatory reaction and destruction of collagen fibers were localized in the area around the apical delta, while the alveolar founding bone, the roots of the teeth and the periodontal ligament at the side of the root surfaces remained normal.
Effects of two gutta‐percha formulations and one zinc oxide‐eugenol and Canada balsam mixture on human blood monocytes and lymphocytes
Authors: Zmener Osvaldo , Goldberg Fernando , Cabrini Rómulo L.
Published: April 2006

Abstract In this study we performed an in vitro assay of the effects of two gutta‐percha formulations and one zinc oxide‐eugenol and Canada balsam‐based endodontic material on the behavior of a mixed cell population of human monocytes and lymphocytes. Cells were cultured either in direct contact with or near experimental samples of Ultrafil, standard gutta‐percha cones or Endoseal and the inhibitory effects of these materials upon cell attachment and spreading on test surfaces were analyzed. Ultrafil and the standard gutta‐percha cones showed little or no adverse effects, whereas the inhibitory effects of Endoseal appeared to be severe. There were statistically significant differences between the results obtained from both Ultrafil and gutta‐percha cones and those obtained from Endoseal. Differences between all tested materials and their respective controls were also statistically significant.
Pulpal healing after luxation injuries and root fracture in the permanent dentition
Authors: Andreasen Frances M.
Published: April 2006

Abstract Pulpal healing patterns were studied in a clinical material of 637 luxated and 95 root‐fractured permanent incisors followed routinely for up to 11 years. It was found that pulpal healing patterns could generally be divided into 3 groups according to the degree of injury sustained by the pulp: little, moderate or severe. Thus after luxation injuries, pulp survival could be without radiographic change (PS), with pulp canal obliteration (PCO) or nonhealing (pulp necrosis (PN)). After root fracture, similar healing patterns could be observed: healing by hard tissue union of fragments (HT), by connective tissue union of fragments (CT) or by nonunion due to interposition of granulation tissue between fragments (GT) resulting from PN of the coronal fragment. In both trauma situations, healing or nonhealing could be determined by type of luxation injury, stage of root development and type of fixation used (forceful application of orthodontic bands vs. passively applied acid‐etch fixation). Pulpal healing complications (PN or GT) were based on clinical findings (coronal discoloration, loss of pulpal sensibility) and radiographic findings (resorption processes of the lamina dura at the root apex or at the level of the root fracture). However, in both injury groups the same changes could also be seen to be intermediate steps in the pulpal healing process. Based on findings from these studies, hypotheses for the mechanics of pulpal healing are proposed as well as guidelines for acute and later treatment of dental luxations, root fractures and the diagnosis of healing complications.
Endodontic status and suggested treatment in a population requiring substantial dental care
Authors: Petersson Kerstin , Lewin Bengt , Hakansson Jan , Olsson Berit , Wennberg Alf
Published: April 2006

Abstract The purpose of this study was to analyse endodontic status and treatment suggested for Swedish citizens requiring substantial dental care. According to the Swedish dental insurance system, treatment plans including radiographs have to be submitted for approval if the estimated cost of treatment exceeds a certain level (USD 500 in 1977). A sample of 1094 treatment plans received during 1977 and 1978 was randomly selected. In the radiographs the number of remaining teeth was recorded, periapical condition was evaluated and the quantity and quality of previous endodontic treatment were estimated. In addition, treatment plans concerning the teeth with periapical lesions were studied. The results indicated that patients analysed in this study that needed expensive treatment had more missing teeth, more root‐filled teeth and more teeth with periapical lesions than what has been reported in previous studies of samples supposed to accurately represent the Swedish population. However, the technical quality of the root fillings and the frequency of periapical lesions in root‐filled teeth were the same as in previous studies, with high frequencies of inadequate root fillings and related unfavourable responses. Thus the patients in this study retained a significant need for endodontic treatment despite having already received a great deal of endodontic care. Further, it was found that nearly half of the observed periapical lesions would not be treated based on the submitted plans.
Dynamics of dentoalveolar ankylosis and associated root resorption
Authors: Hammarström Lars , Blomlöf Leif , Lindskog Sven
Published: April 2006

Abstract The present experimental studies in monkeys were undertaken to study the initiation and progression of dentoalveolar ankylosis of replanted teeth and associated root resorption. Maxillary and mandibular lateral incisors were extracted and replanted after an extraoral period of 15 min or 1 h. Teeth with an extraoral period of 1 h were endodontically treated. Half the number of monkeys were given antibiotics at the time of replantation. The observation periods varied from 2 days to 40 weeks. Irrespective of the length of the extraoral period, initial root resorption and minor areas of ankylosis were found 1 week after replantation. The initial ankylosis was not preceded by root resorption. In teeth replanted after an extraoral period of 15 min the ankylotic area did not increase with increasing time after replantation. Instead the periodontal membrane was re‐established, separating the root surface from the alveolar bone. In teeth replanted after an extraoral period of 1 h, the initial ankylotic area increased with increasing time after replantation. Eight weeks and more after replantation, most of the periodontal membrane was replaced by bone covered by osteoblasts and occasional osteoblasts that were in continuity with the endosteal cells outlining the marrow spaces of the alveolar bone. The cementum and dentin were then gradually resorbed with increasing time after replantation. Antibiotics given at the time of replantation reduced the initial inflammation in the periodontal membrane and the inflammatory root resorption after all observation periods and it also seemed to some extent to prevent bacteria from entering the necrotic pulp tissue. Based on the present results it is suggested that root resorption associated with dentoalveolar ankylosis is initiated by endosteal osteoblasts and is thus a hormonally regulated process. This is in contrast to inflammatory root resorption, which seems to be triggered by inflammatory cells.
Reasons for seeking treatment after traumatic dental injuries
Authors: Garcia‐Godoy Franklin , Garcia‐Godoy Federico , Garcia‐Godoy Federico M.
Published: April 2006

Abstract The purpose of this study was to determine the reasons why parents of children seek treatment after traumatic injuries to primary teeth. The sample consisted of 114 5‐month to 8‐year‐old children with 196 injured primary teeth. The reason for parents seeking treatment varied according to the type of injury. Parents of children with enamel fractures and enameldentin fractures without pulpal exposure were more concerned about esthetics. Of the patients presenting concussions, parents were more responsive to color change of the tooth and to the tooth response to the trauma, mainly abscess formation. In luxations and lateral displacements, the parents sought dental treatment because of their own reaction to the clinical situation, i.e., blood, crying. Very few were concerned with possible consequences to the primary and/or permanent teeth. In no category of injury were the parents most concerned about the consequences to the primary and/or permanent teeth.
A histobacteriological assessment of nonvital teeth after ultrasonic root canal instrumentation
Authors: Rodrigues Homero Habel , Biffi João Carlos Gabrielli
Published: April 2006

Abstract The purpose of this study was to evaluate and discuss the bactericidal effect of ultrasound when applied in the root canal of teeth with necrotic pulp and periapical lesions. Twenty newly extracted teeth were instrumented with an ultrasonic unit and K‐files using 0.5% sodium hypochlorite as irrigating solution. Compacted debris and micro‐organisms were frequently observed in the apical region and in dentinal tubules of the root canal wall. Overinstrumentation that sometimes occurred led to contamination of the periapical lesions with micro‐organisms and debris from the root canal.
Effect of a desensitizing dentifrice on dentinal hypersensitivity
Authors: Ong Grace , Strahan J. Dermot
Published: April 2006

Abstract The objective of this study was to assess the effectiveness of a dentifrice with 2% dibasic sodium citrate in poloxamer 407 in decreasing dentinal hypersensitivity. The test toothpaste was compared with a control toothpaste containing 0.76% sodium monofluorophosphate in a 6‐week double‐blind clinical trial. A total of 75 hypersensitive teeth were examined in the test group, while 100 hypersensitive teeth were in the control group. Changes in hypersensitivity levels were monitored after 6 weeks, using thermal, chemical and mechanical stimuli. At the end of 6 weeks, the test dentifrice was not significantly more effective than the control in decreasing dentinal hypersensitivity. Of the stimuli used, cold was the most effective in eliciting a hypersensitive response, followed by chemical stimulation and air. Heat and toothbrushing caused the least discomfort.
Evaluation of alternatives to chloroform in endodontic practice
Authors: Wennberg Alf , Ørstavik Dag
Published: April 2006

Abstract Chloroform is used in endodontics for plasticizing gutta‐percha points and for facilitating removal of gutta‐percha root canal fillings in need of re‐treatment. Adverse health effects from exposure to chloroform have been reported, and to improve occupational health, it would be advantageous if a less hazardous solvent could replace chloroform. In this study, methylene chloride, methyl chloroform, tetrahydrofuran, xylol and eucalyptol were tested for their capacity to dissolve or soften gutta‐percha points compared with chloroform. The effect of the test solvents was assessed by measuring the depth of penetration of a small indentor of fixed weight and shape into a gutta‐percha disk covered with the test solution for various time periods. Chloroform showed the most pronounced effect, followed by methylene chloride, tetrahydrofuran, and methyl chloroform. When both occupational health and gutta‐percha solvent capacity were considered, methyl chloroform seemed to be an interesting alternative to chloroform.
Some effects of Ledermix® paste and Pulpdent® paste on mouse fibroblasts and on bacteria in vitro
Authors: Taylor Mark Anthony , Hume Wyatt Roderic , Heithersay Geoffrey Sinclair
Published: April 2006

Abstract Dilutions of Ledermix® paste, Pulpdent® paste and a mixture of equal parts by weight of Ledermix paste and Pulp‐dent paste were added to in vitro cultures of mouse fibroblasts or bacteria for 24 h, and various cell functions were then examined: mitosis in and survival of fibroblasts, and survival of Lactobacillus casei or Streptococcus mutans. Ledermix was found to reversibly inhibit mitosis while present in the concentrations range 10−3 to 10−6 mg/ml. Mixing with Pulpdent did not modify this antimitotic effect. Ledermix killed mouse fibroblasts at 10−3 mg/ml and above, while Pulpdent killed at 1 mg/ml and above. The toxic effect of Ledermix was slightly inhibited by mixing it with Pulpdent. Ledermix killed S. mutans at about the same concentration at which it killed the mammalian cells, but required a one thousand‐fold greater concentration to kill L. casei. Pulpdent killed both L. casei and S. mutans at approximately one‐fifth of the concentration at which it killed the mammalian cells. Pulpdent slightly potentiated the antibacterial effect of Ledermix. The pH of Pulpdent was reduced by approximately 0.3 units by mixing with Ledermix. The present data showed that the 50:50 mix of Ledermix and Pulpdent retained the properties examined that are thought to be of therapeutic benefit, while not increasing the toxicity of the component parts to mammalian cells.
Inflammatory resorption: untreated, arrested, prevented
Authors: Remeikis Nijole A. , Stroner William F.
Published: April 2006

Abstract Three human replantation cases are presented wherein the results are in accord with the literature concerning inflammatory resorption and calcium hydroxide therapy. The cases unintentionally simulate a designed experiment wherein the control case received no treatment and the other 2 were subjected to independent variables such as obturation in the hand and the timing of the calcium hydroxide therapy. The untreated case resulted in loss of the tooth, while manipulation of variables in the other two resulted in retention.
Avulsed human teeth replanted within 15 minutes — a long‐term clinical follow‐up study
Authors: Andersson Lars , Bodin Ingrid
Published: April 2006

Abstract Twenty–one avulsed human permanent teeth replanted within 15 min after trauma were followed radiographically for an average of 5 years. Seven teeth did not show any root resorption during the observation period. In 8 teeth shallow resorption cavities were observed, but no signs of progression were observed with increased observation time. In 6 teeth some progressive root resorption was observed with increased observation time. The depth of root resorption cavities was assessed using a radiographic index, and the rate of root resorption was defined as the index change over time. The rate of root resorption was determined. It was concluded that teeth replanted within 15 min after the avulsion have a favourable long‐term prognosis.
Apical placement of needle tip with an injection‐thermoplasticized gutta‐percha technique for root canal obturation
Authors: Lambrianidis Theodor , Veis Alexander , Zervas Panos , Molyvdas Ioannis
Published: April 2006

Abstract It is recommended that when injection‐thermoplasticized gutta‐percha is used as the obturation technique, the root canal space should be prepared in such a way that the 23‐gauge injection needle tip can be placed at a distance 3 to 5 mm short of the working length. In this study the apical seal and extent of gutta‐percha were evaluated when the 23‐gauge tip was placed at a distance 4 mm, 6 mm, and 8 mm short of the working length. Ninty‐nine human single‐rooted mandibular incisors and premolars divided into 3 equal groups were used. Their crowns were separated at the cementoenamel junction and their roots were stored in sodium hypochlorite for 1 week. The roots were then instrumented from size 20 at the working length to size 70:4 mm short of the working length in group A, 6 mm in group B, and 8 mm in group C. Following instrumentation, 3 randomly selected roots of each group were used as control. The remaining 30 roots of each group were covered with aluminium foil and embedded in acrylic blocks. The root canals were then dried, coated with sealer (Roth 811) and obturated by injection of thermoplasticized gutta‐percha using the single‐phase technique. Vertical condensation followed. The roots were immersed in dye for 3 days and then demineralized, dehydrated and cleared in xylene. Measurements of linear dye penetration for the apical seal and for underextension were done by 2 independent examiners under a stereomicroscope. The results of this study showed no statistically significant difference in leakage between the groups. However, statistically significant differences were found in linear underextension between groups A and C as well as between groups B and C, while no significant difference was found between groups A and B.
Microleakage of IRM® used to restore endodontic access preparations
Authors: Anderson R. W. , Powell B. J. , Pashley D. H.
Published: April 2006

Abstract The effect on microleakage of varying the powder‐to‐liquid ratio (P/L) of IRM® used to restore endodontic access preparations was evaluated. Crowns of noncarious, nonrestored extracted human teeth were used in this study. Microleakage was measured using a fluid filtration technique prior to access preparation to obtain control measurements. After access preparation, IRM restorations were placed using P/L of 2, 3, 4, 5, and 6 g/ml, using the manufacturer's recommended dispensing scoop and dropper, and using 2 P/L in a new capsulated IRM delivery system (IRM CAPS). Microleakage measurements were made after various time intervals and after thermal stress. The results indicated that the lower P/L provided the best seals. All groups demonstrated significant microleakage measurements after thermal stress. Significantly greater microleakage measurements were obtained with the P/L of 6 g/ml and the manufacturer's recommended dispensing scoop and dropper. A P/L of 2 g/ml demonstrated less microleakage than the other groups tested.
Demonstration of Bacteroides intermedius in periapical tissue using indirect immunofluorescence microscopy
Authors: Barnett Frederic , Stevens Roy , Tronstad Leif
Published: April 2006

Abstract The presence of bacteria in periapical lesions of teeth with necrotic pulp has been demonstrated by microbiological sampling of periapical lesions during endodontic surgery. The purpose of this study was to confirm the presence of Bacteroides intermedius in a periapical granuloma using an indirect immunofluorescence technique. Histologic sections of a periapical granuloma were incubated with a rabbit antiserum to B. intermedius. After incubation with secondary antibody (fluorescein‐conjugated goat anti‐rabbit IgG), an intense fluorescent staining was observed in areas of the tissue sections. Control tissue sections that were incubated without the antibody remained unstained. The results obtained with the indirect immunofluorescence technique supported our cultural findings that microorganisms, e.g. B. intermedius, were present in the tissue of the periapical granuloma.
Pulp revascularization in reimplanted immature monkey incisors – predictability and the effect of antibiotic systemic prophylaxis
Authors: Cvek Miomir , Cleaton‐Jones Peter , Austin John , Lownie John , Kling Margareta , Fatti Paul
Published: April 2006

Abstract In 32 monkeys 105 immature maxillary incisors were extracted and reimplanted either immediately or after 30 or 60 min wet or dry storage. Of the monkeys, 17 (group I) did not receive and 15 (group II) received prophylactic treatment with 4 mg/kg doxycycline before extraction and 2 mg/kg for 5 d after reimplantation. The observation time varied from 6 to 8 weeks. After being histologically processed, the material was evaluated with respect to the amount of vital tissue and presence of microorganisms in the pulpal lumen. A comparison revealed no difference in the results between the groups. The results were therefore pooled and statistically analysed with respect to the significance of apical foramen width, extra‐alveolar time, wet or dry storage and presence of micro‐organisms in the pulpal lumen for the occurrence of complete pulp revascularization (CPR). The overall frequency of CPR was 18%. Log‐linear analyses (SAS, 1985) of the material as a whole or of separate parameters consistently revealed a relationship between presence of microorganisms and absence of CPR (P= 0.0001). A higher frequency of CPR and a lower frequency of micro‐organisms (P= 0.05) was found only for the group of immediately reimplanted teeth. The presence of micro‐organisms could be explained for 61 teeth. In 27 of these, blood clots containing bacteria in the apical portion of pulpal lumen indicated contamination during the extra‐alveolar time, while in 34, the micro‐organisms originated from plaque covered mechanical damage in the cervical part of the root surface.
Relationship of intracanal medicaments to endodontic flare‐ups
Authors: Trope Martin
Published: April 2006

Abstract The purpose of the study was to compare the effect of three intracanal medicaments on the incidence of post‐instrumentation flare‐ups. All teeth were instrumented to a predetermined minimum size using a 0.5% solution of sodium hypo‐chlorite as the irrigant. Formocresol, Ledermix, and calcium hydroxide were placed in strict sequence irrespective of the presence or absence of symptoms or radiographic signs of apical periodontitis. The patients were given written post‐operative instructions and a prescription for 600 mg ibuprofen to be taken if mild to moderate pain developed. If severe pain and/or swelling developed the patient was instructed to call the office immediately and was considered to have had a flare‐up. Twelve flare‐ups occurred in teeth with radiographic signs of apical periodontitis; none in teeth without periapical radiolucencies. Six of the twelve flare‐ups occurred in retreatment cases and the other six occurred in teeth without previous endodontic treatment. No significant difference was found in the flare‐up rate among the three intracanal medicaments.
Unusual case of general pulp calcification (pulp stones) in a young Greek girl
Authors: Siskos G. J. , Georgopoulou M.
Published: April 2006

Abstract An unusual case of generalized pulp calcification is reported in a 14‐year‐old Greek girl. Radiographic examination revealed large pulp stones in all permanent teeth located in the pulp chamber and sometimes extending to the coronal portion of the root canal. The patient's dental, medical and family history, as well as the findings from the clinical examination were non‐contributory. Biochemical analysis of one pulp stone removed from the right maxillary central incisor revealed large amounts of urates, proteins and phospholipids, but a blood test of the patient showed no metabolic disturbance. Therefore, it is suggested that this unusual case may be of idiopathic origin.
Prevalence of apical periodontitis and results of endodontic treatment in middle‐aged adults in Norway
Authors: Eriksen H. M. , Bjertness E.
Published: April 2006

Abstract The present investigation based on a random sample of 50‐year‐olds from Oslo, Norway, indicate a prevalence of apical periodontitis of 3.5% of the teeth present. Forty‐four percent of the endodontically treated teeth presented with a radio‐graphically detectable periapical radiolucency. There was a statistically significant negative correlation between the quality of the root fillings evaluated and prevalence of apical periodontitis.
Rapid orthodontic extrusion of crown root and cervical root fractured teeth
Authors: Malmgren Olle , Malmgren Barbro , Frykholm Anders
Published: April 2006

Abstract This study concerns the relapse tendency and extent of root resorption in 33 extruded non‐vital crown root fractured or cervical root fractured teeth in 32 patients 10–20 years old. They constitute all orthodontically extruded teeth at the Orthodontic or Pedodontic Departments, Eastman Institutet, Stockholm (1982–1987). A simple extrusion mechanism exerted a force of 60–70 p along the root axis of the tooth. An extrusion of 2–3 mm was obtained in most patients; the most extreme effect was 6 mm. In 16 patients the extrusion was achieved within 3 weeks, in 12 it lasted for 4–6 weeks and in 5, 7–9 weeks. The treatment was more complicated in the lower jaw. After the extrusion, a fibrotomy was done and in most patients also a gingival recon–touring to create an optimal relation between the gingiva and the margin of the restoration. Periodically identical radiographs were taken immediately before and after the extrusion, after 3 months and after 1 year. A minor relapse, about 0.5 mm, was observed in 3 patients. Limited root resorption was found in 6 teeth and severe in only 1. The resorptions did not progress in the following 2 years of observation.
An in vitro comparison of root canal content extrusion using ultrasonic and hand instrumentation
Authors: Lee S.‐J. , Lee C.‐S. , Strittmatter E. J.
Published: April 2006

Abstract The purpose of this study was to evaluate apical extrusion of root canal content using ultrasonic and hand instrumentation. Forty‐nine tooth models were fabricated with clear resin. Each model contained a canal in the center. Each tooth model was mounted in a plastic cube (1 × 1 × 2 cm) with white dental plaster so that the coronal 2–3 mm of the model was exposed for instrumentation. Methylene blue dye with glycerin was used as a marker for root canal content. The study consisted of three groups. In group I, Enac ultrasonic instrumentation was used 1 mm from the apex; in group II, Enac ultrasonic instrumentation was used 3 mm from the apex; in group III, K Files were used with a push‐pull instrumentation technique, 1 mm from the apex. After instrumentation the resin models were extracted and the plaster blocks were sectioned through the long axis of the models. Photographs were made of the area of apical leakage and the amount of dye penetration was measured using a planimeter. There were no differences between hand instrumentation and both ultrasonic groups. At p<0.05, ultrasonic instrumentation 3 mm from the apex leaked significantly more than the ultrasonic instrumentation 1 mm from the apex.
Delayed endodontic and prosthetic treatment of two traumatized incisors
Authors: Hülsmann M. , Engelke W.
Published: April 2006

Abstract This case report describes the delayed endodontic and prosthetic treatment of two maxillary central incisors in a 16‐year‐old patient. Both teeth had been traumatized eight years previously. The examination revealed arrested root formation with wide open apices, periapical inflammation and inflammatory resorption. Endodontic treatment with calcium hydroxide led to formation of hard tissue barriers in both teeth so that definite obturation could be performed. One tooth was lost due to a deep crown‐root‐fracture and replaced by an intraosseous implant, whereas the other incisor was retained for nearly four years.
Retrograde approaches in endodontic therapy
Authors: Friedman Shimon
Published: April 2006

Abstract The routine use of retrograde fillings during apical surgery, as well as the material of choice for that purpose, have been debated. A retrograde filling is placed so as to seal an infected root canal causing periapical pathosis. Therefore, retrograde root canal fillings should be performed routinely during apical surgery regardless of the apparent technical quality of the root canal obturation, unless orthograde endodontic treatment is performed in conjunction with surgery. When orthograde treatment is not performed in conjunction with surgery. When orthograde treatment is not performed, retrograde root canal filling enhances the prognosis of apical surgery. An array of potential retrograde filling materials have been extensively investigated in vitro and in vivo. Once that the biocompatibility of the materials is confirmed a clinical comparison, rather than in vitro sealability studies, is the most valid evaluation method. Some of the difficulties encountered in long term clinical studies in patients may be avoided in animal studies. The review of the relevant literature of the past decade suggests that amalgam used in conjunction with cavity varnish is the retrograde filling material of choice. It must be stressed, however, that retrograde filling is not comparable to debridement and obturation of the entire root canal. Therefore, when the only way to approach the root canal is from the apical direction, rather than placing an apical retrograde filling, a retrograde endodontic treatment of the entire canal should be preferred, if it is feasible.
Retrograde root filling with composite and a dentin‐bonding agent. 2.
Authors: Rud J. , Munksgaard E.C. , Andreasen J.O. , Rud V.
Published: April 2006

Abstract Investigations on retrograde root filling using a composite resin, Retroplast, bonded to the root surface with the dentin‐bonding agent Gluma have been described. Here, detailed information is given about the surgical procedures. The aim was to obtain a thin retrograde composite filling on the root apex, made slightly concave, sealing the main root canal, accessory canals as well as dentinal tubules. Hemostasis was obtained primarily by applying 1% adrenaline and by using a needle suction tip, and care was taken not to damage the surrounding tissues by the various chemicals. The healing results, after up to 1 year, of 388 cases of various tooth types, treated with either retrograde composite or with amalgam were compared. The healing classification included four categories: 1) complete healing; 2) fibrous healing; 3) uncertain; and 4) failures. In the composite group, the healing rates were as follows: 74% showed completely healing, 4% fibrous healing, 15% uncertain and 7% were failures. In the amalgam group, 59% showed complete healing, 3% fibrous healing, 30% uncertain, and 8% were failures. Complete healing occurred significantly more often after filling with Retroplast than after filling with amalgam (p<0.00005). Significantly fewer proportion to other tooth types. The number of immediate postoperative complications did not differ significantly between the composite and the amalgam groups.
Delayed treatment of a mid‐root fracture
Authors: Heling I. , Zalkind M.
Published: April 2006

Abstract A case of delayed treatment of a mid root fracture is presented. A radiolucent lesion at the fracture line was treated with calcium hydroxide in the coronal fragment for nine months. Clinically, the tooth became firm and the radiographic results showed healing of the lateral lesion and hard tissue filling in the space at the fracture line.
Thermomechanical compaction of gutta‐percha: a scanning electron microscope study
Authors: Zmener Osvaldo , Frias Jose Gimenes
Published: April 2006

Abstract The root canals of 20 freshly extracted maxillary central incisors and canines were prepared and filled by thermo‐mechanical or lateral condensation of gutta‐percha cones without sealer. The adaptation of the filling material to the root canal walls was then examined with a scanning electron microscope. A more homogenized mass of gutta‐percha could be detected in teeth filled by thermomechanical compaction of gutta‐percha cones. The morphology of the prepared root canal system was well reproduced by the use of both techniques.
Neurotoxic effect of two root canal sealers with calcium hydroxide on rat phrenic nerve in vitro
Authors: Boiesen Jan , Brodin Pal
Published: April 2006

Abstract Root canal sealers placed into contact with the inferior alveolar nerve can cause paraesthesia in the area innervated by this nerve. The paraesthesia is due to neurotoxic effects of the sealers. In this study we examined the effect on nerve conduction in vitro of two calcium hydroxide‐containing root canal sealers, Sealapex and CRCS. An isolated rat phrenic nerve was placed between two suction electrodes in a bath containing Tyro‐de solution. The sealers were brought into contact with the nerve, and the evoked compound action potentials (cAP) were recorded before and after contact with the materials. Both Sealapex and CRCS induced a fast and complete inhibition of the cAP in this model. The degree of reversibility of the inhibition varied from experiment to experiment. Both materials exhibited reversible and irreversible block of the nerve conduction after 90s and 5 min exposure. However, after 30 min of contact, the conduction of the cAP was irreversibly blocked for both materials.
Follow‐up after periapical surgery: the value of the one‐year control
Authors: Halse Agnar , Molven Olav , Grung Bjarte
Published: April 2006

Abstract A total of 474 teeth treated with periapical surgery were examined after one year. Complete healing was unequivocally demonstrated for 250 teeth. Two hundred and fourteen teeth were scheduled for further follow‐up, and of these, 194 (91%) could be followed until a stable situation was recorded. Of 41 cases judged as completely healed after one year, but with initial observer disagreement, only 2 (5%) failed later. The 76 cases showing incomplete healing (scars) after one year with few exceptions ended as completely healed or persisted as incomplete healings. The uncertain group (n = 72) was equally re‐distributed as successes (completely or incompletely healed) or failures at the end control. Five cases showing no healing after one year all ended as failures. Based on these findings it is concluded that the one‐year control will provide a valid diagnosis for the majority of cases. Only a minor number, the uncertain healings, need further follow‐up.
A case of progressive external root resorption
Authors: Zmener Osvaldo , Kuperman Jorge A.
Published: April 2006

Abstract This case report describes a radiographical, histological and histochemical study of an extracted mandibular tooth with progressive external root resorption. The cells which appeared to be responsible for the hard tissue resorption showed an intense acid phosphatase activity, similar to that of bone‐resorbing cells. Some aspects on the etiology and pathogenesis of resorptive process that occurred in the present case are discussed.
Effect of root canal infection and treatment of traumatized primary incisors on their permanent successors
Authors: Holan G. , Topf J. , Fuks A. B.
Published: April 2006

Abstract The purpose of the present retrospective study was to evaluate the effect of trauma, root canal infection and treatment of non‐vital primary incisors on their permanent successors. A total of 117 permanent central incisors were examined clinically and radiographically for the presence of discolorations, hypoplasia, or disturbances in root development. Of these, 29 were succedaneous to traumatized, endodontically involved and treated primary incisors (Group A). Another 29 had (heir traumatized, endodontically involved, primary predecessors extracted or left untreated (Group B). The remaining 59 incisors were intact and had no history of trauma (Group C). Severe hypoplasia could not be observed in any of the teeth, and no disturbances in root development could be disclosed radiographically. The incidence of defects in Groups B and C was similar, whereas in Group A it was 2 or 3 times higher than in each of the other two groups. Despite this fact, root canal treatment of traumatized non‐vital primary incisors should be considered a treatment option, as premature extraction of a primary incisor may lead to speech problems, premature eruption and/or malalignment of the permanent successor, or affect the child's self image.
Exposure of dental personnel to chloroform in root‐filling procedures
Authors: Allard Urban , Andersson Lennart
Published: April 2006

Abstract The exposure of dental personnel to chloroform in root‐filling procedures was evaluated. Four different root filling procedures were studied. In all the procedures studied, gutta‐percha was used as the root‐filling material and chloroform or sealers containing chloroform were used. Ten teeth in each group were root‐filled. In the first group, chloroform and 5% rosin in chloroform were administered in medical cups, in the second group chloroform and Kloroperka NØ was administered in medical cups. In Group three a specially designed glass tube (S‐endodip) was used for administration and in the fourth group specially selected plastic tubes were used. In the last two groups the sealers were chloroform and 5% rosin in chloroform. When medical cups were used the exposure reached levels close to the accepted limit values in Sweden, indicating that only one root filling per day can be performed without the dental team being unacceptably exposed. Using either the glass tube or the specially designed plastic tube, the exposure was significantly reduced for the dentist (p< 0.005) and for the nurse (p< 0.005). The mean exposure was 19.1 mg/m3 for the dentist and 11.6 mg/ m3 for the nurse in the first experimental group. The mean values in the second group were 15.4 mg/m3 and 16.6 mg/m3 respectively. In the third group, the dentist was exposed to a mean of 4.4 mg/m3 and the nurse to 6.3 mg/m3 In the fourth group, the mean exposure was 2.2 mg/m3 and 3.4 mg/m3 respectively. The results of this study indicated that chloroform in combination with 5% rosin in chloroform could be used safely if care was taken and the liquids were administered in special tubes.
Lay and professional knowledge of methods for emergency management of avulsed teeth
Authors: Stokes Alastair N. , Anderson Heather K. , Cowan Tony M.
Published: April 2006

Abstract Proper treatment during the first 30 minutes offers the best prognosis for traumatically avulsed teeth. This study sought to determine both lay people's and dental professionals’ knowledge of and attitude to emergency procedures. A 12‐question survey was administered to 5 groups: (a) parents of learner swimmers and (b) coaches of college sports teams (lay); (c) State Dental Nurses, (d) dentists and (e) dental nurse/receptionists (professional). Respondents totalled 184 (a 32, b 86, c 24, d 18, e 24) i.e. 118 lay and 66 professional. Data revealed that group b had the greatest personal experience of avulsed teeth and groups c and e the least. Public hospital accident and emergency services (A & E) were perceived by all groups as most available. 18% of lay groups could not cite an emergency service. Lay people thought first of A & E for management whereas professional groups preferred the victim's own dentist. Most professional people would replant avulsed permanent teeth and about 1/3 would replant deciduous teeth: 1/2 lay people would replant permanent teeth and 1/8 deciduous teeth. Where treatment was not straightforward lay people would seek advice before acting. Half of the lay groups would transport an avulsed tooth dry. All the professionals had had advice on management of avulsed teeth but only 1/4 of the lay groups. This study highlighted the need for educational campaigns aimed at members of the lay public likely to be involved in the emergency management of traumatically avulsed teeth.
Comparative immunohistochemical identification and relative distribution of immunocompetent cells in sections of frozen or formalin‐fixed tissue from human periapical inflammatory lesions
Authors: Tani Nobuyuki , Osada Tamotsu , Watanabe Yoshihisa , Umemoto Toshio
Published: April 2006

Abstract The presence of immunocompetent cells (B, Th/i and Ts/c cells and macrophages) and the ratios of these cell populations in periapical lesions (radicular granulomas, radicular cysts and apical scars) were demonstrated immunohistochemically using paraffin and cryo‐sections. Thirty‐four human periapical lesions were examined for the presence of immunocompetent cells by monoclonal antibodies and the biotin‐avidine‐horse‐radish peroxidase method. The T/B cell ratio of radicular cysts was significantly higher than that of both radicular granulomas and apical scars, and the average number of Th/i cells was greater than that of Ts/c cells in the radicular granulomas. However, no significant difference was found between radicular cyst and apical scar. The number of macrophages in radicular granulomas was significantly higher than that of the other lesions. These findings suggested that periapical lesions develop as a result of both humoral and cell‐mediated immunological response and indicated that the ratios of immunocompetent cells are different in the different types of periapical lesion.
Observations of acoustic streaming fields around an oscillating ultrasonic file
Authors: Ahmad M. , Roy R. A. , Kamarudin A. G.
Published: April 2006

Abstract The steady acoustic streaming generated around straight and precurved oscillating ultrasonic files driven by the Piezon‐Master 400 unit was examined in the free field and in small channels using a stereomicroscope. In addition, the effect of file‐wall contact on streaming production was also investigated. The results indicated that the ultrasonic files can generate acoustic streaming both in the free field and in the small channel. Higher velocity streaming was observed when smaller size files were employed and when the file was precurved. Light file‐wall contact did not totally inhibit streaming while severe file‐wall contact inhibited movement of the file and, as a result, no streaming was observed. The positions and length scales of the streaming vortices appeared to be influenced by the presence of boundaries. In the free field, two rows of vortices were situated along the sides of the file while in the small channel, the vortices were positioned above the surface of the file. These results indicated that it is possible for acoustic streaming to occur in a confined space as in a root canal provided that severe file‐wall contact is avoided. It is therefore recommended that light filing or allowing the file to freely vibrate during some stage of treatment should be carried out in order to generate streaming in the root canal.
Two‐dimensional distribution of sound velocity in ground sections of dentin
Authors: Löst C. , Irion K.‐M. , John C. , Nüssle W.
Published: April 2006

Abstract The longitudinal velocity of sound in a specific material depends, amongst others, on the material's density and elasticity (Young's Modulus). Ultrasound therefore may be used for indirect characterization of materials. In this paper a method is described which allows high resolution measurements on co‐planar ground sections of human teeth. The results are presented in two‐dimensional velocity profiles. There is evidence from the first images, that longitudinal sound velocity (LSV) in dentin varies depending on the location. The use of LSV may be another way to characterize hard dental tissues physically, and to monitor induced changes.
Frequency and type of dental traumas in mandibular body and condyle fractures
Authors: Ignatius Eino T. , Oikarinen Kyösti S. , Silvennoinen Urpo
Published: April 2006

Abstract Dental injuries in association with 207 mandibular fractures were evaluated from patient files and radiographs. It was shown that 32% of the dentulous patients with condylar fractures had dental injuries, approximately 3.7 traumatised teeth per patient, most of which were dental hard tissue injuries and situated typically in the maxillary molar region. Dental injuries were diagnosed in 30% in association with mandibular corpus fractures, approximately 3.6 traumatised teeth per patient, and injuries were more often dental luxations in the anterior part of the mandible. It was found that 143 teeth were involved in the line of mandibular corpus fracture of 105 patients (1.4 per patient). More than half of the fracture lines were diagnosed as passing the periodontal ligament.