bluuebunny/crossref_metadata_2025 huggingface dataset:
Penetration of dentin by different conditioners in vitro: a quantitative study
Authors: Meryon S. D. , Tobias R. S. , Johnson S. G.
Published: April 2006

Abstract Conditioning agents are known to remove the smear layer that forms on cut dentin with the resultant opening of the orifices of the dentinal tubules. However, much controversy exists over the depth to which these agents penetrate the residual dentin and whether they might damage the underlying pulp. In view of the enormous technical difficulties of studying the depth of penetration of such agents in vivo, an in vitro study was undertaken. Dentin slices of known thickness were prepared with an intact smear layer on both surfaces. The upper surface was treated with the test conditioner, and the depth of penetration was assessed using SEM by the degree of removal of the dentin plugs blocking the orifices of the dentin tubules in the lower untreated surface. No significant penetration of 200 μm slices occurred and only slight penetration of 100 and 50 μm slices. There was little difference in the degree of penetration achieved by the 5 agents studied. The results presented suggest that the chemical toxicity of the conditioners tested will not damage the pulp if the residual dentin depth is greater than 200 μm.
Endodontic treatment and immunopathology of periapical granuloma in an AIDS patient
Authors: Gerner Nina Wiencke , Hurlen Bjern , Dobloug Jan , Brandtzaeg Per
Published: April 2006

Abstract The complications of endodontic treatment in an AIDS patient are described and related to the immunopathological findings in a periapical granuloma. The lesion contained abundant polyclonal immunoglobulin‐producing plasma cells but was virtually devoid of CD4‐positive T cells (putative “helper” phenotype), indicating compromised local immune function. Delayed healing of apical periodontitis after endodontic treatment of teeth with periapical lesions was found in several teeth in this case. Root canal treatment of teeth with vital pulps was performed successfully. Extraction of teeth and endodontic treatment in combination with root resection were uneventful.
Solubility and biocompatibility of calcium hydroxide‐containing root canal sealers
Authors: Tronstad Leif , Barnett Frederic , Flax Michael
Published: April 2006

Abstract The solubility and biocompatibility of 2 commercially available calcium hydroxide‐containing root canal sealers, CRGS and Sealapex, were studied. Four dogs were anesthetized and a sulcular incision was made to expose the vestibular surface of the mandble. Two rows of holes, 2 mm deep, 2 mm wide and 10 mm apart, were drilled into the mandible. Teflon cups with the same dimensions as the holes were filled with the experimental materials and placed in the cavities. For the purpose of comparison, Teflon cups filled with a traditional zinc oxide‐eugenol sealer and a paste of calcium hydroxide and saline were implanted as well. After 90 days the animals were killed. The mandibles were dissected free, fixed in formalin and demineralized. Bone specimens containing 1 Teflon cup were then embedded in paraffin, sectioned longitudinally, and the sections were stained with hematoxylin and eosin and examined in the light microscope. The cups which originally contained the paste of calcium hydroxide and saline were completely filled with bone. Sealapex was partly missing from the cups and was generally replaced by ingrowth of connective tissue. Large amounts of the material were seen in macrophages and tissue outside the cups. CRCS and the traditional zinc oxide‐eugenol sealer generally filled the cups well after 3 months. Tissue fluids were seen in the superficial layers of these materials, but ingrowth of tissue had not occurred. No macrophage reaction was seen with either of these materials, but a stronger inflammatory reaction was caused by CRCS than by the traditional zinc oxide‐eugenol cement. CRCS appeared to be the most stable of the calcium hydroxide‐containing sealers tested.
Root fractures: a case of dental non‐intervention
Authors: Pan Cheung Shun , Walker Richard T.
Published: April 2006

Abstract Root fractures are combined injuries to the dentine, cementum, pulp and periodontal ligament. A number of questions related to the healing patterns of such injuries remain unanswered. A case report is presented in which satisfactory healing of root fractures occurred, in the absence of invasive management, over a 5‐year period.
Iatrogenic vertical root fractures in endodontically treated teeth
Authors: Tamse Aviad
Published: April 2006

Abstract A survey of 31 published cases and 11 original cases of vertical root fractures due to iatrogenic reasons revealed that most of the vertical root fractures in endodontically treated teeth occurred in mandibular bicuspids and molars in patients aged 41–60 years. The diagnosis of vertical root fracture is difficult because of the late appearance of the signs and the appearance of pure endodontic or periodontal problems. This survey revealed that the most common cause of vertical root fracture in endodontically treated teeth is the excessive force used during lateral condensation of gutta‐percha. Widening of the periodontal ligament along one or both sides of the root, or bone loss in solitary tooth are the major radiographic findings. Mild pain or discomfort and swelling are the major clinical symptoms, and solitary pocket around one aspect of the suspect tooth is the major clinical sign.
Monoinfection of root canal with Pseudomonas aeruginosa
Authors: Ranta Kari , Haapasalo Markus , Ranta Helena
Published: April 2006

Abstract A successful treatment of a persisting endodontic infection with Pseudomonas aeruginosa is described together with a review of its presence in saliva and root canal infections. The treatment included ethanol irrigation and prolonged calcium hydroxide therapy in addition to thorough mechanical preparation. The minimum pH value of calcium hydroxide for in vitro killing of the isolated strain was found to be above 10.
Progression of root resorption following replantation of human teeth after extended extraoral storage
Authors: Andersson Lars , Bodin Ingrid , Sörensen Stefan
Published: April 2006

Abstract Avulsed human permanent teeth subjected to a minimum of 1 h dry extraoral storage before replantation were followed radiographically for an average of 4.8 years. 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 frequency of inflammatory and replacement resorption was determined at each observation time. Replacement resorption increased in frequency with time in all patients. In teeth endodontically treated within 3 weeks of replantation, minimal inflammatory resorption was found regardless of the age of the patients. In teeth where endodontic treatment was performed more than 3 weeks after replantation, the frequency of inflammatory resorption was significantly higher in young patients but not in older patients, up to more than 3 years after replantation. The rate of root resorption was found to be related to age. In patients 8–16 years old at the time of avulsion the rate of root resorption was significantly higher compared with patients 17–39 years old. Age had a higher impact on the rate of root resorption compared with the delay in endodontic treatment after replantation. It was concluded that a tooth replanted with a necrotic periodontal membrane will become ankylosed and resorbed within 3–7 years in young patients, whereas a tooth replanted under similar conditions in older patients may remain in function for a considerably longer time.
An enigmatic sinus tract origin
Authors: Kaufman Arieh Y.
Published: April 2006

Abstract Diagnosis of the origin of a sinus tract is very complex. In this case report, a sinus tract stoma appeared above the left maxillary incisor, but the causative tooth was the right maxillary incisor. Incorrect diagnosis led to endodontic treatment of a healthy tooth followed by apicoectomy, which was also ineffective. An endodontic consultation revealed the true origin of the sinus tract. Five days after completing conservative endodontic treatment of the right maxillary incisor, the sinus tract disappeared. This case confirms the need to include a diagnostic tracing radiograph as part of routine diagnostic procedures.
Luxation injuries to permanent teeth — a retrospective study of etiological factors
Authors: Crona‐Larsson Gunbritt , Norén Jörgen G.
Published: April 2006

Abstract Trauma to permanent teeth with luxation injuries often leads to clinical treatment problems. Traumatic injury patients in local clinics are often limited in number. The aim of this investigation was to retrospectively study the etiological factors in luxation injuries to permanent teeth in relation to sex, age, time of year and diagnosis. A total of 108 files from patients, aged 6 to 19 years, with 196 teeth with luxation injuries, were collected. The maxillary central incisors represented 70% of all teeth injured and 70% of the teeth belonged to children between 8 and 12 years of age. Falls (34%) and bicycle‐riding (30%) were the most frequent reasons for trauma, followed by sports (14%) and assaults (13%). Boys were more often involved in trauma. Girls were as often involved in sports accidents as boys. Subluxation was the most frequent diagnosis (77%), followed by extrusion, intrusion, exarticulation and lateral luxation. Accidents were reported most frequently during spring and early summer. A slight increase was also noted during autumn.
Enamel hypoplasia of a maxillary central incisor
Authors: Morfis Andreas S.
Published: April 2006

Abstract This article describes a case of a permanent central incisor with enamel hypoplasia. A 7‐year‐old patient had suffered an injury in a car accident when she was 21/2 years old. The maxillary right central deciduous incisor was lost in the accident. At the time of examination a fistula was present buccally to the maxillary right permanent incisor, which had erupted only 3 mm into the mouth. The maxillary left central incisor had erupted fully. After clinical and radiographic examination the lost deciduous incisor was found in the bone buccally to the permanent incisor. The deciduous tooth was extracted surgically, the fistula healed and the gingiva became normal. The permanent incisor had a 3‐mm‐wide zone of hypoplastic enamel on the buccal surface of the crown.
Xeroradiography and its application to dentistry
Authors: Katsanulas Thomas , Lambrianidis Theodor
Published: April 2006

Abstract Xeroradiography is a highly accurate electrostatic imaging technique. In this technique a conventional single‐phase dental x‐ray unit is used as an x‐ray source, but instead of a silver‐halide film image, a uniformly charged selenium alloy plate housed in a light‐proof cassette is used. In this article the equipment, procedure, properties and artifacts related to the xeroradiographic technique are described. An evaluation of the xeroradiographic images is also presented. Xeroradiography, which requires only about one‐third of the dose required for conventional radiographs, is a valuable alternative to conventional radiography for detecting carious lesions, calculus deposits and periodontal disease. It is also of value in interpreting periapical structures.
Use of an electronic apex locator in the treatment of teeth with incomplete root formation
Authors: Hülsmann Michael , Pieper Klaus
Published: April 2006

Abstract An electronic apex locator was used to determine length and control apical bridge formation in the treatment of teeth with incomplete root formation. Measurements were taken in 10 teeth in which apexification therapy had just started and in 11 teeth where the formation of the apical barrier was considered to be complete. In the beginning of the apexification therapy, when the apical foramen was still open, endometric measurements gave incorrect results in all instances. After apical closure had occurred and definite obturation of the root canal seemed possible, the apex locator in all teeth gave correct results and complete agreement was obtained between the radiographs and the electronic tests. Even in teeth in which complete apical closure could not be obtained, the results of electronic measurements were correct. Electronic apex locators may be used as auxilliary devices in controlling apical hard tissue closure in the treatment of teeth with incomplete root formation.
Some observations on the mechanics of oscillation of ultrasonic files
Authors: Ahmad Majinah
Published: April 2006

Abstract The resonant characteristics of ultrasonic files driven by the Cavi‐Endo unit were examined. The investigation was carried out by evaluating the pattern of oscillation and the power emitted by the ultrasonic files. It was observed that the files oscillated in a sinusoidal fashion, exhibiting a standing wave pattern along the file. The power emitted was found to be directly proportional to the flexibility of the file. Such behaviour is typical of a system that exhibits resonance.
In vivo fractures of endodontically treated posterior teeth restored with amalgam
Authors: Hansen Erik Keith , Asmussen Erik , Christiansen Niels C.
Published: April 2006

Abstract The cumulative survival rate (retention of both cusps) and the fracture pattern of 1639 endodontically treated posterior teeth were assessed in a retrospective study. All teeth had an MO/DO or an MOD cavity restored with amalgam without cuspal overlays. The 20‐year survival rate of teeth with an MO/ DO cavity was markedly higher than that of teeth with an MOD cavity. The lowest survival rate was found for the upper premolars with an MOD cavity: 28% of these teeth fractured within 3 years after endodontic therapy, 57% were lost after 10 years, and 73% after 20 years. Generally, the cusp most prone to fracture was the lingual one, and lingual fractures caused significantly more damage to the periodontal tissues than did facial or total crown fractures. The severity of periodontal damage increased with posterior location of the tooth. By far the most serious failures, irrespective of the cavity type, were found for the upper second molar, as 10 of 29 fractures led to extraction. It is concluded that amalgam, especially in MOD cavities, is an unacceptable material for restoration of endodontically treated posterior teeth if used without cuspal overlays.
A systematic approach to preventing intracanal breakage of endodontic files
Authors: Sotokawa Tadashi
Published: April 2006

Abstract This study was conducted to determine the effectiveness of a method to prevent intracanal breakage of endodontic files. An application schedule with a predetermined number of periods of use for K‐files of all sizes was implemented at the author's clinic for a 3‐year period. All the files used under this schedule were discarded after the predetermined periods of use, whether they displayed any deformity or not. During the 3‐year period, 1933 files (53.7 per month) were discarded after preparation of 3269 root canals. There were 5 file fractures (0.1 per month) compared with 1.4 fractures per month before the adaption of this system. The monthly average of files discarded during the 3‐year research period was 53.7. Before the adoption of the trial system, the monthly average of discarded files was 76.5. It is concluded that the experimental system effectively reduced the incidence of intracanal instrument fractures and the total number of files consumed.
Tissue response to an experimental calcium hydroxide‐based endodontic sealer: a quantitative study in subcutaneous connective tissue of the rat
Authors: Zmener Osvaldo , Guglielmotti Maria B. , Cabrini Rómulo L.
Published: April 2006

Abstract Silicone tubes containing a freshly mixed experimental Sealapex, in which titanium dioxide was removed from the original formula, were implanted in the dorsal subcutaneous connective tissue of the rat. Solid silicone rods of the same size as the tubes were also implanted and used as inert controls. The tissue reaction to both these materials was histometrically and quantitatively studied under light microscopy and by elemental electron microprobe analysis. After 7, 30 and 90 d of implantation, different grades of tissue reaction to the tested materials were recorded. A granulomatous tissue containing numerous foreign‐body giant cells and macrophages with engulfed particles in their cytoplasms was initially detected in contact with the test material. In addition, many fibroblasts and newly formed vessels were also observed at these areas. The results of this study revealed that these reactions increased progressively at the 30‐and 90‐d observations. The electron microprobe analysis of the granulomatous tissues showed the presence of heavy components of the experimental material.
Disinfection by endodontic irrigants and dressings of experimentally infected dentinal tubules
Authors: Ørstavik Dag , Haapasalo Markus
Published: April 2006

Abstract The effect of endodontic irrigants and dressings was tested on bacteria in bovine dentin specimens experimentally infected with Enterococcus faecalis, Streptococcus sanguis, Escherichia coli, or Pseudomonas aeruginosa. Standardized, cylindrical dentin test pieces were prepared and cleaned by ultrasonic treatment with EDTA and sodium hypochlorite. The specimens were infected with the test organism for periods up to 14 days, and the degree of infection into the tubules was monitored using Brown & Brenn stain, scanning electron microscopy, and culturing of dentin dust from sequential bur samples starting from the pulpal side. E. faecalis rapidly infected the whole length of the tubules; S. sanguis required up to 2 weeks for complete infection; E. coli only penetrated to some 600 μm, even after prolonged incubation periods. P. aeruginosa infected dentin quickly, but apparently in very low numbers. E. faecalis persisted for at least 10 d after withdrawal of nutrient support, whereas the other 3 organisms died within 4 to 48 h. Endodontic medicaments were applied to infected specimen for comparison of antibacterial potency. Camphorated p‐monochlorophenol was generally more efficient than Calasept, and of the irrigants tested, iodine potassium iodide appeared more potent than sodium hypochlorite or chlorhexidine. The presence of a smear layer delayed, but did not eliminate, the effect of the medicaments.
Toxicity of root canal sealers on rat bone cells in primary culture
Authors: Takahara Katsuhiko , Onodera Atsushi , Matsumoto Koukichi
Published: April 2006

Abstract The cytotoxic effects on cultured rat bone cells of newly‐developed root canal sealers and commercially available sealers were compared. Various root canal sealers were applied to cultured bone cells obtained from rat calvaria by the enzyme digestion method. Measurement of [3H]‐thymidine incorporation, alkaline phosphatase activity, and calcium release were performed after 24 and 48 h. No significant difference was found in cellular DNA synthesis and alkaline phosphatase activity between cells exposed to New B‐l, New B‐5 and controls after exposure for 24 and 48 h. Cells in contact with Tubliseal, Diaket and AH‐26 demonstrated a significant difference from controls in DNA synthesis and alkaline phosphatase activity. Calcium release at 24 h was significantly different in the cells treated with New B‐1 and New B‐5 than in controls. No appreciable difference was found, however, between New B‐6, Sealapex and controls. At 48 h, cells treated with New B‐l, New B‐5 and New B‐6 showed differed significantly difference from controls, but the cells exposed to Sealapex did not. The newly‐developed root canal sealers had lower toxicity in vitro than five types of commercially available root canal sealers.
A six‐year follow‐up study of sports‐related dental injuries in children and adolescents
Authors: Häyrinen‐Immonen Ritva , Sane Juha , Perkki Kaarle , Malmström Maria
Published: April 2006

Abstract The records were analyzed of 106 patients with sports‐related dental traumas treated in 1983 at the public oral surgery unit in Helsinki, Finland; 51 were examined six years after injury. The mean age was 11.8 years (range 7‐24 years). The woman/man ratio was 1:3. In 39% of cases, the injuries had arisen from ice hockey or skating; 30% happened during school hours; 80% were uncomplicated crown fractures, concussions or subluxations. During the six‐year follow‐up, of 80 teeth in 51 patients, root resorption was found in 6 teeth (7.5%), periapical lesions were noted in 2 teeth (2.5%), and obliteration of the pulp was seen in 4 teeth (5%). Three teeth (3.7%) had suffered loss of vitality. The pulp had been extirpated in 13 of the traumatized teeth (16%). In all, 13.7% of the patients were found to have complications six years later. The results showed that long follow‐up periods are needed after dental injury.
Subcellular localization of glutaraldehyde
Authors: Ranly D. M. , Amstutz L. , Horn D.
Published: April 2006

Abstract Glutaraldehyde (GA) has been proposed as an alternative to formocresol for pulpotomies in primary teeth and as an irrigant in root canal therapy. These studies were undertaken to determine if GA can associate with the nucleus of living cells, thereby posing a mutagenic threat. Rats were infused IV with 14C‐GA and killed 5 min and 1 h later. The cystolic, membrane, and nuclear fractions of harvested liver cells were separated and analyzed for radioactivity. We determined that significant radioactivity was located in the cytosol and membrane fractions, but not in the nuclear fraction. In an in vitro experiment, liver slices were incubated with 14C‐GA in sealed vials in which 14C‐CO2 was captured. After 1 h the nucleic acids of the liver slices were isolated and counted. In vitro the liver cells incorporated and metabolized GA to CO2 but no significant label could be detected in the isolated nucleic acids. We concluded from these experiments that GA which was incorporated into liver cells did not reach the nucleus to a significant extent, and that its potential for mutagenicity in the context of pulp treatment was nil.
Glass ionomer cements and dental pulp
Authors: Mjör I. A. , Nordahl I. , Tronstad L.
Published: April 2006

Abstract Only slight pulp reactions to glass ionomer cements occurred when inserted in Class V cavities of dog teeth. Most inflammatory reactions were due to bacteria at the tooth/filling interface. Special dentin reactions were noted in almost half the teeth, including hematoxyphilic bands in the dentin and a disturbance of the mineralization pattern of predentin. The clinical significance of these dentin reactions is not known.
Vitality of human lip fibroblasts in milk, Hanks balanced Salt solution and Viaspan storage media
Authors: Hiltz J. , Trope M.
Published: April 2006

Abstract The purpose of the study was to compare the effect of storage in milk, Hanks balanced salt solution (HBSS) and Viaspan on the vitality of human lip fibroblasts. Confluent monolayers of the fibroblasts were grown in Petri dishes. The growth medium was poured off and replaced in 27 dishes each with Viaspan, fresh whole milk and Hanks balanced salt solution respectively. Three of original plates were plate contained at confluence. At times ranging from 2 to 168 hours the average number of vital cells remaining was measured using the trypan blue exclusion test. The groups stored in milk maintained a high percentage of vital cells for 6 hours (68.2%). At 12 hours milk's effectiveness had dropped to 43.4% vital cells and it was not effective at all at 48 hours (0.024% vital cells and it was not effective at all at 48 hours with 71. 3% vital cells remaining. At by 120 hours no cells survived. Viaspan was the most effective storage medium at all observation periods and at 168 hours still had 37.6% vital cells present.
Canal markings produced by endosonic instruments
Authors: Walmsley A. D. , Murgel C. , Krell K. V.
Published: April 2006

Abstract It has been recognised that ultrasonic files leave a diagonal pattern within the canal following endosonic instrumentation. There is confusion on the causative factor on the production of these marks. Furthermore there is little information about the marks produced by sonic files. An in vitro system consisting of highly polished dentin discs demonstrated that the ultrasonic K‐file made a diagonal pattern that was an imprint of the cutting edges of the file. The sonic files produced different markings which were the result of their longitudinal and transverse motion. Root canals of extracted teeth were prepared with these instruments and similar grooves were observed. The ultrasonic K‐file had diagonal grooves in the coronal and middle third of the root canal but longitudinal marks in the apical third. The rispisonic and shaper files produced debris even in the presence of NaOCl. This debris was formed into discrete parallel bands. Both longitudinal and transverse grooves were present and the canal had many other scratches similar to those seen with the dentin discs. There were differences between the marks produced by either ultrasonic or sonic endosonic instruments but it is unknown whether this influences the long term prognosis of the root canal therapy.
Healing of the guinea pig incisor after partial pulp removal
Authors: van Mullem P. J.
Published: April 2006

Abstract A histological and microradiographical study was made of eruption and healing of guinea pig lower incisors after endodontic treatment compared with intact incisors. One incisor per animal was cut perpendicularly at the level of the gingiva. One third to one half of the pulp was removed. The experimental periods were 0, 4, 7, 16, 21 and 31 days. Unstained, HE or Brown and Brenn stained sections were studied microscopically. Some teeth were sectioned undecalcified and studied microradiographically. In intact incisors the dentin matrix deposition and mineralization were described. In the dentin, incisally to the pulp proper, narrow canals, the walls of which consisted of mineralized material, were found opening at the occlusal surface. Histologically, in the treated teeth, a beginning of cell‐rich fibrodentin deposition at the original dentin wall was present at Day 4. At Day 7 a substantial walling off of the pulp is achieved by cell‐rich and some cell‐poor fibrodentin. After 16 days large amounts of cell‐rich and cell‐poor fibrodentin were covered by some tertiary dentin. After 31 days the amount of tertiary dentin was larger than after 16 days and also covered the incisal part of the root canal walls. Further apically some vasodentin and newly formed normal, secondary, dentin was observed. In course of this period the cells of the cell‐rich and cell‐poor fibrodentin first showed necrobiosis, then necrosis. The cell‐rich fibrodentin appeared not fully mineralized. All blood vessels and strands of soft tissue which ran in canals in the fibrodentin came to a dead end. Thus the root canal was fully obturated. Although the teeth appeared (nearly) normal to the naked eye and radiographically after 31 days, histologically they were not. Large amounts of fibrodentin still being present incisally which showed the dual potential of the guinea pig pulp to produce both fibrodentin and orthodentin.
In vitro efficacy of sodium perborate preparations used for intracoronal bleaching of discolored non‐vital teeth
Authors: Rotstein Ilan , Zalkind Maya , Mor Chaim , Tarabeah Atif , Friedman Shimon
Published: April 2006

Abstract Bleaching materials containing 30% hydrogen peroxide have been used successfully for the treatment of discolored non–vital teeth. Intracoronal application of these materials was occasionally associated with the development of external root resorption. Extracted human teeth with intact crowns were discolored in vitro and bleached with three preparations of sodium perborate. These preparations included: sodium perborate with 30% hydrogen peroxide, sodium perborate with 3% hydrogen peroxide and sodium perborate with water. The bleaching materials were placed in the pulp chamber of the discolored teeth and sealed with IRM for 14 days. They were replaced with fresh preparations after 3 and 7 days. The coronal tooth shades were evaluated after 3, 7 and 14 days and a comparison of the bleaching success of the groups was made at each interval. It was found that after 14 days and three bleachings there was no significant difference in success between the groups. It is therefore recommended that sodium perborate be used in combination with water rather than with hydrogen peroxide to reduce the risk of post‐bleaching external root resorption.
Cytotoxicity of eugenol in sealer containing zinc‐oxide
Authors: Gulati N. , Chandra S. , Aggarwal P. K. , Jaiswal J. N. , Singh M.
Published: April 2006

Abstract In this study two zinc‐oxide‐based root canal sealers were compared for their tissue toxic response. The sealers tested were zinc‐oxide eugenol and zinc‐oxide glycerine. Fifteen albino rats were used for the study and were injected subcutaneously in the preset state. The tissue response was assessed by counting the polymorphonuclear cells at Day 1, Day 7 and Day 15 of the study period. The inflammatory response was graded according to the mean polymorphonuclear counts in the five rats for each period. The results showed that the toxicity was greater for the eugenol‐containing sealer and increased during the three time intervals. For the non‐eugenol sealer the response was milder and reached a peak by 7 days after which it decreased.
Effect of luxation injuries on permanent teeth
Authors: Crona‐Larsson Gunbritt , Bjarnason Sibilla , Norén Jörgen G.
Published: April 2006

Abstract Trauma to the supporting tissues of the teeth are among the most common dental injuries, leading to such complications as pulp canal obliteration, necrosis and root resorption. The aim of this investigation was to study the outcome for young permanent teeth subjected to luxation injuries. From 108 dental records 171 teeth with injuries to the supporting tissue were selected. The material comprised 130 subluxated, 15 extruded, 9 intruded, 15 exarticulated and 6 laterally luxated teeth in children aged 6–19 years. Apart from luxation, 59 teeth (35%) had additional crown and root fractures. 65% of the teeth recovered without complications. 78% of the subluxated teeth and 24% of the luxated teeth showed uneventful posttraumatic healing. Concomitant uncomplicated crown fractures or root fractures without displacement of the coronal fragment did not interfere with the healing. Of 60 teeth with healing complications, 52 (87%) were subsequently recorded as healed, the remaining 8 were extracted or had progressive root resorption. Loss of pulp vitality and external root resorptions were the most often recorded complications (28% and 17% of the total material respectively). Pulp canal obliteration was noted in 3% of the cases. Extent of injury and degree of tooth maturity were found to be related to healing compliations.
Traumatic bone cyst: case report
Authors: Abbott P. V.
Published: April 2006

Abstract The traumatic bone cyst is a lesion whose aetiology and pathogenesis have not been conclusively established. There are several theories and names for this lesion and various forms of management have been reported in the literature. This report outlines the clinical and radiographic findings associated with a case of a traumatic bone cyst. Laboratory investigations were also carried out and their findings are reported. This case was treated jointly by the endodontic and oral surgery departments of an institution and demonstrates the need for close follow‐up from both departments. In particular, the endodontic aspects of monitoring the pulp status of teeth in the region of such a bone lesion are emphasised.
An experimental study of the stability of irradiated teeth in the region of the dentinoenamel junction
Authors: Pioch Thomas , Golfels Doris , Staehle Hans Jõrg
Published: April 2006

Abstract In this in vitro study we investigated the influence of ionizing gamma rays on the stability in the region of the dentinoenamel junction. We removed the enamel on the labial surface of 30 incisors of bovines up to the dentinoenamel junction, so that a circular area of enamel with a diameter of 2.0 ± 0.1 mm was left and an enamel cylinder was created. 15 teeth were irradiated by a cobalt‐60‐source (energy dose 70 Gy). The other 15 teeth were used as controls. Using a material testing apparatus the shear bond strengths were measured by breaking off the enamel cylinders. Furthermore, the breaking modes were investigated in SEM. Comparing the results of the shear bond strength experiments, it was obvious that the stability in the region of the dentinoenamel junction was significantly less among the irradiated teeth than among the non‐irradiated teeth. The median value of the gamma ray treated teeth was x̃= 19.1 MPa and that of the non‐ray‐treated teeth was x̃= 37.4 MPa. The non‐irradiated teeth showed fractured surfaces only in dentin in 10 cases and in 5 cases in both dentin and enamel. In contrast to that, the irradiated teeth had fractured surfaces in 12 cases exclusively in dentin and only in 3 cases the enamel was also fractured. These results lead us to conclude that changes of biophysical property of teeth can be caused by the influence of ionizing rays.
Apical root canal anatomy in the dog
Authors: Masson Eric , Hennet Philippe R. , Calas Paul L.
Published: April 2006

Abstract 240 permanent teeth from 8 different dogs aged 1, 3, 8, 10, 15 years, were used for an anatomic study. The teeth were cleaned, their root canal system was stained with dye, then the teeth were decalcified and cleared to determine the root canal anatomy. The apical root canal anatomy in dogs can be described as a “sprinkler‐rose” anatomy: at the tip of the pulpal canal, the canal is divided in numerous narrow channels radiating peripherally through the dentin and the cementum and ending in numerous apical foramina on the cementum surface. This architecture constitutes a very complex apical delta.
Resistance to vertical fracture of roots, previously fractured and bonded with glass ionomer cement, composite resin and cyanoacrylate cement
Authors: Friedman Shimon , Moshonov Joshua , Trope Martin
Published: April 2006

Abstract A recently developed glass ionomer bone cement (Ionos) may be suitable for bonding vertically fractured teeth, but the resulting resistance to repeated fracture of the bonded teeth is unknown. The purpose of this study was to assess in vitro the resistance to repeated fracture of roots which were previously fractured and bonded with Ionos cement and other bonding agents. Thirty‐six roots were separated at the cervix and grooved on the coronal surface. Each root was mounted in an Instron machine and a vertical force was exerted until fracture occurred. Both the force required to fracture the root (F) and the root surface area (A) were recorded, and the root halves were bonded with one of the following materials: Ionos bone cement without dentin etching, Permabond 910 cyanoacrylate adhesive, and Gluma bonding system. The bonded roots were maintained in a wet sponge. One week later the roots were re‐fractured in the Instron machine, and the forces were recorded (RF). Each one of F, RF, A. and the ratios RF/F and RF/A were compared statistically among the three experimental groups. Overall, RF was at the most 20% of F. Statistically significant differences were obtained only in RF, RF/F, and RF/A (p<0.0003). Roots bonded with Ionos cement demonstrated significantly lower values than roots bonded with Permabond and Gluma, both of which did not differ significantly. It was concluded that roots bonded with Ionos cement were the least resistant to re‐fracture, due to a lesser bonding strength of Ionos bone cement as compared with Permabond and Gluma.
Comparison of the guarding capacities of mouth protectors
Authors: Oikarinen K. S. , Salonen M. A. M. , Korhonen J.
Published: April 2006

Abstract The guarding capacity of seven mouth protectors (Erkoflex 3.0 and 4.0, Erkoloc 3.0, 4.5 and 5.5, TranSheet/Perform and TranSheet/LiteLine) was tested mechanically on 20 plaster models, two or three tests on each mouth protector. Two tests on a plaster model without the protector screed as control. An appliance was constructed to simulate the impact of an ice‐hockey puck on the teeth, the plaster model was fixed onto the device and the minimum force needed to break the plaster teeth under the protector was recorded. The average total thickness and that of the soft and hard layers of the labial plates of each mouth protector were recorded along with the average thickness of the cervical and incisal hard and soft layers. The results showed that the best protection was achieved with the TranSheet/LiteLine model, followed by TranSheet/Perform and Erkoloc 5.5 and 4.5 mouthgards. All these had a resilient layer against the teeth, and it was shown in stepwise regression analysis that the only property having a statistically significant effect on the guarding capacity was the thickness of this cervical soft layer.
Bio‐microscopical observation of dystrophic calcification induced by calcium hydroxide
Authors: Wakabayashi Hajime , Horikawa Manami , Funato Akiyoshi , Onodera Atsushi , Matsumoto Koukichi
Published: April 2006

Abstract Calcium hydroxide paste was introduced into a rabbit ear chamber, and the effect of calcium hydroxide on the vascular tissue was observed under a biomicroscope continuously up 10 14 weeks. Many precipitates were observed at the border of living tissue, after the dissolution of microvessels around the paste. They increased both in size and number to combine like a river bank in the first 48 h. After 1 week, microcirculation recovered, and newly‐formed capillaries approached the precipitate‐bank, the edge of which became smoother as weeks went by. The bank was stable and compatible to microvessels during the observation period. By SEM observation, the width of the bank was from 200 to 400 μm, and the tissue‐side of the bank appeared like amorphous lamellae, while the inner‐side showed particle‐like appearance. EDX examination revealed high peaks of Ca and P similar to calcium phosphate at the tissue‐side of the bank, but only Ca peak at the inner‐side. The precipitates seemed to have the potential to induce dystrophic calcification by absorbing Ca and P from the tissue.
Endodontic status of mandibular premolars and molars in Swedish adults. A repeated cross‐sectional study in 1974 and in 1985
Authors: Petersson Kerstin
Published: April 2006

Abstract The purpose of the study was to find out whether the prevalence of endodontically treated teeth and teeth with apical periodontitis, as observed in the mandibular premolar and molar region., was lower in 1985 compared with 1974 in the adult Swedish population. Another purpose was to determine whether the technical quality of the root fillings had improved between 1974 and 1985. The material examined consisted of periapical radiographs of the mandibular premolar and molar region in 861 of 1;502 people sampled in 1974 and in 586 of 726 people sampled in 1985 both representing an adult Swedish population. The observations in this study of the prevalence of endodontically treated teeth and teeth with apical periodontitis in 1985 and in 1974 indicated a markedly improved endodontic health in the adult Swedish population in the age‐groups under 40 years in 1985 compared with 1974. These findings were in line with observations on the number of intact and restored teeth in the same cross‐sectional samples. Another finding was an improved technical quality of the root fillings in 1985 compared with in 1974. Favourable periapical conditions were observed in teeth with adequately obturated root canals in 1985 as well as in 1974.
Introduction to four custom‐made mouth protectors constructed of single and double layers for activists in contact sports
Authors: Oikarinen Kyösti S. , Salonen Maarit A. M.
Published: April 2006

Abstract Four mouth protectors are introduced, all manufactured by dentists familiar with small‐scale technical work. Mouth protectors made of Erkoflex or Erkoloc sheets are moulded in an Erkopress device under a vacuum, while the Tran Sheet/Perform and Tran Sheet/LiteLine mouth protectors are constructed of a hard outer shell (Triad TranSheet, light‐cured polyurethane dimethacrylate) and a soft inner part against the labial surface of the front teeth (Perform or LiteLine, both light‐cured polyurethane dimethacrylate), thus minimizing the impact on individual teeth and better preventing dental traumas. The technical construction of the mouth protectors is illustrated, as is the need for instrumentation and its costs and the materials required to manufacture these mouth protectors.
Effects of systemic and topical nicotine on pulpal blood flow in dogs
Authors: Johnson William T. , Johnson Georgia K. , Todd Gordon L. , Fung Yiu K.
Published: April 2006

Abstract It has been suggested that nicotine exerts cardiovascular effects which are similar to stimulation of the sympatho‐adrenal system. If this observation is true, nicotine administration would decrease pulpal blood flow and possibly alter the pulpal response to injury. The purpose of this study was to measure pulpal blood flow in dogs using the radiolabelled microsphere method following topical or systemic administration of nicotine for 28 days. Thirteen dogs were divided into three groups. Group one received topical nicotine (8 mg nicotine/kg/day) combined with orabase which was applied in two equal doses to the mandibular anterior gingiva. Group two received systemic nicotine (2.5 mg/kg/day) delivered by osmotic pumps implanted subcutaneously in the back of each animals' neck. Group three were controls, and these animals received either topical orabase twice daily applied to the mandibular anterior gingiva or saline via osmotic pumps. Results indicated pulpal blood flow increased from Day 0 to Day 28 in both nicotine treated groups. Group one (topical nicotine) exhibited a mean increase in blood flow of 21.8 ml/min/100 g. while group two exhibited a mean increase of 50.1 ml/min/100 g. Group three, the control animals, exhibited a mean decrease in pulpal blood flow of 22.1 ml/min/100 g over the 28‐day interval. These changes were not statistically significant (p > 0.05).
Efficacy of laser Doppler flowmetry in determining pulp vitality of human teeth
Authors: Ingólfsson Ægir Rafn , Tronstad Leif , Hersh Elliot V. , Riva Charles E.
Published: April 2006

Abstract – The aim of this study was to examine if laser Doppler flowmetry (LDF) could aid in distinguishing teeth with necrotic pulps from vital teeth and if so, which configuration of 5 experimental probes would give the best results. Each probe had 3 fibers arranged in a triangle. One fiber carried the laser light to the pulp tissue and 2 fibers carried the back‐scattered light to the detector giving the output signal. The distance between the 3 fibers in the triangular arrangement in each probe was 250, 500, 800, 1000, and 1500 jam. A special rubber‐base splint was used to hold the probe in place on the buccal surface of the tested teeth. Eleven anterior teeth with clinically diagnosed necrotic pulp were measured with the LDF method and the results compared to contralateral teeth with vital pulp. For the sake of comparison, 10 pairs of anterior teeth with vital pulps in 10 patients were tested as well. The LDF signals were fed into an analog printer and a lap‐top computer where all calculations were done. With the LDF method, the output signals from the teeth with necrotic pulps were significantly lower with all 5 probes than the output signals from the contralateral vital teeth. On average, the signal was 42.7% lower from the teeth with necrotic pulps than from the vital teeth. Four of 11 teeth with necrotic pulp gave a positive response to an electrical pulp tester (EPT). The results suggested that the probe with the smallest separation of fibers was the most sensitive in distinguishing necrotic pulps from vital ones.
Timing of calcium hydroxide therapy in the treatment of root resorption in replanted teeth in dogs
Authors: Gregoriou A. P. , Jeansonne B. G. , Musselmann R. J.
Published: April 2006

Abstract The effect of time of the onset of calcium hydroxide (CH) pulpectomy on root resorption of 31 permanent dog incisors was investigated. CH pulpectomy was delayed 4, 9, 14 and 18 days after the teeth were extracted and replanted. Control teeth were replanted 1) without pulpectomy, 2) with a pulpectomy only or 31. with a pulpectomy and CH filling. All teeth were prepared for histologic evaluation 8 weeks after the teeth were replanted. Cross section were examined using a computer microscope and linear (jam) and/or square areas (μm2) of surface (SRR), inflammatory (IRR), and replacement (RRR) root resorption were calculated. From this data the percentage of linear and area resorption was averaged for each group. Duncan multiple range t‐test (P<0.05) revealed that teeth in which a pulpectomy with CH filling was done extraorally had significantly greater SRR than the rest of the groups; teeth in which a pulpectomy without CH filling was done extra orally had significantly greater RRR than teeth in which CH pulpectomy was delayed for 18 days; there was no significant difference in SRR. IRR or RRR when CH placement was delayed 4, 9, 14 or 18 days after replantation. Although it was not significant the overall resorption was least when CH pulpectomy was delayed 18 days.
A radiographic study of the effect of various retrograde fillings on periapical healing after replantation
Authors: Andreasen J. O. , Pitt Ford T. R.
Published: April 2006

Abstract An effective retrograde sealing procedure places great demands upon both technique and materials. Prevention of microleakage, biocompatibility and stability of the material in the apical tissues arc very important. To evaluate potential retrograde tilling materials, a replantation model has been developed in which extracted permanent molars were replanted in monkeys after apicectomy of each root, preparation of a 2‐mm deep retrograde cavity and its sealing with various dental materials. Prior to retro‐filling the remaining pulp was exposed 10 saliva. Apicected molars which were infected and did not receive retrograde fillings served as positive controls. Periapical healing was evaluated radiographically after 8 weeks based on planimetric measurements of the size of the periapical radiolucency. The following dental materials were tested: amalgam, glass ionomer cement, calcium‐hydroxide lining cement. AH 26 root canal sealer, various zinc oxide‐eugenol cements. Cavil, and gutta‐percha with various sealers. The materials which were associated with better apical healing than the infected controls were glass ionomer cement, Cavit, and the zinc oxide‐eugenol cements. When plain zinc oxide‐eugenol or IRM Were Combined with a gutta‐percha core, healing was best and not statistically different from normal apices. It was concluded that radiographic assessment at 8 weeks of molar teeth retrograde filled prior to replantation could be a valuable method for discrimination of potentially useful materials in vivo.
Maxillary molar root fracture caused by sinus surgery: case report
Authors: Jerome C. E.
Published: April 2006

Abstract A case is presented in which a horizontal root fracture of the mesiobuccal root of a maxillary first molar was diagnosed as the source of a patient's chronic pain. Horizontal root fractures arc rare in posterior teeth. The source of the fracture was determined to be trauma from access or curettage during two Caldwell‐Luc sinus procedures. A detailed history and endodontic retreatment led to the diagnosis. A mesiobuccal root resection resolved the chronic pain.