bluuebunny/crossref_metadata_2025 huggingface dataset:
Hyaluronidase‐enhanced connective‐tissue attachment to demineralized root and pulpal dentin
Authors: Hanes P. J. , Polson A. M. , Frederick G. T. , Thomas H. F.
Published: April 2006

Abstract Treatment of demineralized dentin with hyaluronidase seems to increase exposure of collagen fibrils. The present study compared the in vivo connective‐tissue response to dentin treated with citric acid alone and with citric acid plus hyaluronidase. Dentin specimens were obtained from areas beneath attached periodontal ligament fibers on extracted human teeth. Each rectangular specimen had a face of root surface dentin and an opposite surface composed of pulpal dentin. One group was treated with citric acid alone (A); a second group with both citric acid and hyaluronidase (AH); and a third group served as untreated controls (C). Specimens were examined in the scanning electron microscope (SEM) for morphologic characteristics, and used in an implantation model to evaluate cell, connective‐tissue and epithelial responses. In the latter procedures, specimens were implanted transcutaneously into incisional wounds on the dorsal surfaces of rats. Four specimens in each group were evaluated 10 days after implantation and analyzed using histologic and histometric methods.

SEM examination showed that the surface of the control specimens had a smear layer which concealed the openings of dentinal tubules. Dentinal tubule orifices were present on the surface of A and AH specimens. Enhanced exposure of the collagen fibrils was apparent on AH surfaces. The histologic and histometric analyses of A and AH groups showed that cell adhesion and fiber density did not differ between root and pulpal surfaces, or between A and AH‐treated implants. However, a significantly greater number of cells were attached to A and AH surfaces than controls. In addition, fiber attachment was not present in the control group. A distinct eosinophilic surface zone was present on A and AH surfaces, which was significantly wider on pulpal surfaces and in AH specimens. The connective‐tissue attachment that occurred in A and AH groups inhibited epithelial down‐growth. The length of implant surface exhibiting connective‐tissue attachment was significantly greater in AH specimens. It appeared that hyaluronidase treatment of the exposed collagen had increased the area of connective‐tissue attachment to the implant surface.
Clinical performance of three endodontic sealers
Authors: Ørstavik Dag , Kerekes Kasmer , Eriksen Harald M.
Published: April 2006

Abstract The clinical performance of three endodontic sealers, AH 26®, Kloroperka N‐Ø® and ProcoSol®, was assessed in a prospective study of endodontic treatment in 810 roots. The roots were treated by undergraduate students according to a standardized procedure, and were filled with laterally condensed gutta‐percha and sealer. The sealer was randomly selected just prior to filling. The patients were recalled yearly for 4 years for a clinical and radiographic control examination, and the radiographs were scored using the periapical index (PAI) scoring system. Ridit analysis provided optimal discrimination between subgroups of roots with regard to the radiographic status of the periapical tissues as a measure of the clinical performance of the materials. The periapical status of roots filled with AH 26® or ProcoSol® was better than that of roots filled with Kloroperka®. The difference was significant after 1 year and persisted through the 4‐year observation period. The difference was also evident after stratification of the material with regard to preoperative pulpal and periapical diagnoses. It is concluded that the choice of sealer may influence the outcome of endodontic treatment, and that the perapical index is a useful discriminatory tool for assessment of treatment results in endodontics.
Direct pulp capping: a review
Authors: Lim Kian Chong , Kirk Ewen Eric James
Published: April 2006

Abstract The healthy pulp has good healing potential when it is exposed, although the exact repair mechanism is still undetermined, and it is not material‐specific. Calcium hydroxide appears to promote the healing process and is the most widely accepted capping material. Paste‐type calcium hydroxide formulations are more consistent in promoting healing of pulp exposures than cement forms where bacterial microleakage is eliminated. The prognosis for pulp capping with calcium hydroxide is good if the pulp has no pre‐existing symptoms of pain, and the environment provided for it is suitable. This requires the absence of blood clots and bacterial contamination. Where there are some symptoms of pain in a vital tooth, pretreatments with suitable materials improve the prognosis.
Functional fixation for traumatically luxated teeth
Authors: Oikarinen Kyösti
Published: April 2006

Abstract A splinting method is described for the fixation of traumatically luxated or auto transplanted teeth. The splint is constructed from a thin stainless steel wire by an acid‐etching technique. The composite is applied to the wire only on the enamel surface, thus leaving the interdental space uncovered. The splint meets most of the demands of tooth fixation and serves as a means of functional fixation, as it allows slight vertical movement of the teeth. The reliability of electrometric pulp‐testing during splinting was examined on 3 people with a root‐filled upper central incisor. It is shown that if the test is performed palatally after thorough drying of the enamel, no false positive results are achieved. A case report on the fixation of exarticulated upper central incisors in an 11‐year‐old girl is also presented.
Late complications of luxation injuries to teeth
Authors: Oikarinen Kyösti , Gundlach Karsten K.H. , Pfeifer Gerhard
Published: April 2006

Abstract The 172 periodontally injured teeth of 76 patients were examined clinically and radiographically 6–32 months (mean 22 months) following injury. Multiple linear regression analysis, in which all the variables examined were forced into the model, was used to study the effect of three variables (stage of root formation, type of luxation, and duration of immobilization) in conjunction with one or two variables having the highest explanatory effect on 4 radiographically diagnosed late complications: external replacement resorption, pulp obliteration, loss of marginal alveolar bone and periapical inflammatory changes. External root resorption was found in 19% of cases and was only statistically related to the type of first aid treatment (p< 0.001), although the duration of immobilization was a more decisive factor for ankylosis than the other two variables. Partial or total obliteration of the pulp was recorded in 24% of the teeth examined and was statistically related to the age of the patient (p< 0.001) and the stage of root formation (p<0.05). Loss of marginal alveolar bone was dependent on the age of the patient (p< 0.001) and the duration of immobilization (p<0.05). Dislocation upon injury was the most decisive single factor affecting the radiographic periapical inflammatory changes (p<0.001).
In vitro study of the sealing ability of four retrograde filling materials
Authors: Beltes Panajiotis , Zervas Panos , Lambrianidis Theodor , Molyvdas Loannis
Published: April 2006

Abstract This in vitro study utilized India ink dye after clearing to evaluate the extent of apical microleakage following reverse filling procedures. Forty single‐rooted human teeth divided into 4 groups were chemomechanically prepared and obturated, using the lateral condensation technique with gutta‐percha and Grossman sealer. Following obturation, an apicoectomy was performed and retrograde cavities were filled with 4 different materials: Group A: amalgam and varnish; Group B: EBA cement; Group C: Ketac‐cem®; Group D: hot‐burnished gutta‐percha. All teeth were immersed in India ink, decalcified, cleaned, examined through a stereomicroscope, and the depth of linear dye penetration was measured. Statistical analysis showed significantly less dye penetration with EBA cement and amalgam with varnish than with Ketac‐cem and hot‐burnished gutta‐percha.
C‐shaped root canals in mandibular second molars in a Chinese population
Authors: Yang Zu‐Pyn , Yang Shu‐Fen , Lin Yi‐Chu , Shay Jin‐Chuan , Chi Cherng‐Yeong
Published: April 2006

Abstract The purpose of this investigation was to study the prevalence of C‐shaped roots, root canal orifices, and root canals in the mandibular second molars of a Chinese population. A total of 581 second mandibular molars were collected in Hong Kong and Taiwan. The teeth were demineralized and placed in methyl salicylate to induce transparency. The pulp chamber floor was examined to ascertain the number of root canal orifices. Chinese ink was then injected into the root canal system to demonstrate the root canal anatomy. The mandibular second molars had separate roots in 66.4%, cone‐shaped roots in 2.1% and C‐shaped roots in 31.5%. The C‐shaped roots had C‐shaped canal orifices in 68.3% (21.5% of whole material). True C‐shaped root canals were observed in 65.8% of the teeth with C‐shaped orifices and in 13.9% of the whole material. Separate root canals were seen in 34.2% of the teeth with C‐shaped orifices. Separate canal orifices were found in 31.7% of the C‐shaped roots and 7.4% of these roots had true C‐shaped canals. In the whole material 0.9% of the roots with individual canal orifices had C‐shaped canals. In conclusion, C‐shaped root canals were common in mandibular second molars in the Chinese subjects studied. The C‐shaped root canals were often, but not always recognized because of a C‐shaped canal orifice.
Dental trauma in contact team sports
Authors: Sane Juha , Ylipaavalniemi Pekka
Published: April 2006

Abstract Dental injuries occurring from 1979–1985 in Finland in 6 contact team sports (American football, bandy, basketball, team handball, ice hockey and soccer) were studied. A total of 23,395 accidents occurred among registered players; 1526 (6.5%) of these accidents affected the dental structures. Contact between players caused over half of the accidents and a blow from a stick every third accident. Crown fractures were the most common type of dental injury, occurring most often to the maxillary central incisors. In most accidents (58.6%) only one tooth was affected. The highest rate of incidence was found in ice hockey (8.9%) and the lowest in American football (1.4%). The low incidence in American football was due to adequate facial and dental protection that is mandatory in this sport.
Histological and bacteriological study of pulps extirpated after luxation injuries
Authors: Andreasen Frances M.
Published: April 2006

Abstract In a material of 637 luxated permanent teeth, it was found that 26 teeth (4.2%) which initially demonstrated the classical signs of pulp necrosis had reverted to normal appearance and sensibility at later examination, indicating that a revascularization and reinnervation process of the traumatized pulpal tissue had taken place. A histological and histobacteriological analysis was made of 66 pulps in the same population that had been extirpated due to suspected pulpal necrosis after injury, in order to examine whether similar changes could also have occurred in these teeth. It was found that the pulps studied were either non‐infected (n = 27), infected (n= 11) or totally autolyzed (i.e. not enough tissue for histological examination (n = 28)). In contrast to teeth with autolyzed or infected pulp tissue, 12 of the 27 non‐infected specimens showed signs of pulpal revascularization and/or apparent scattered cell survival. These pulps were assumed to have a potential for healing (i.e. revascularization and reinnervation of the pulp). Most clinical and radiographic parameters appeared not to be associated with pulpal infection of cell/tissue integrity. Only the length of the observation period and tenderness to percussion were found to be related to the histological status (i.e. presence or absence of pulpal infection, cellular versus acellular stroma). It was concluded that the present criteria for pulpal necrosis cannot discriminate between infected pulp necrosis and cases where healing might take place. Whether healing processes would actually lead to repair of the pulp could not be determined with the present material.
Bleaching of discoloured root‐filled teeth
Authors: Holmstrup Grete , Palm Anne Merete , Lambjerg‐Hansen Harry
Published: April 2006

Abstract In this study a simple and time–saving method for bleaching of discoloured root‐filled teeth is presented. The method used sodium perborate moistened with water and the access cavity is temporarily sealed with Cavit® between visits. Bleaching was carried out in 95 teeth, with a satisfactory initial result in 90% of the cases. After 3 years of observation, recurrence of discolouration was found in 20% of the teeth seen at follow‐up examination. The method is easy, fast and essentially without complications. It is therefore recommended as an alternative to full crown restoration, assuming the tooth is not too weakened because of large fillings.
Sealing ability of thermoplasticized gutta‐percha in root canal obturation using a sectional vs. a single‐phase technique
Authors: Veis Alexander , Beltes Panos , Liolios Evangelos
Published: April 2006

Abstract Properly prepared straight root canals of freshly extracted maxillary canines and central incisors were used to evaluate the sealing ability of the sectional thermoplasticized gutta‐percha obturation technique, with or without sealer and the single‐phase thermoplasticized gutta‐percha filling technique. The teeth were divided into 3 groups (A, B, C) of 20 teeth and were obturated using the 3 thermoplasticized gutta‐percha techniques. Group A: single phase with sealer; group B: sectional technique without sealer; and group C: sectional technique with sealer. The obturated teeth were immersed in India ink for 3 days followed by clearing procedures. The teeth were then examined under a stereo microscope and the linear leakage was recorded. Statistical unpaired Student's t‐tests showed significantly less dye penetration in teeth obturated using the sectional technique with sealer (group C) than in teeth obturated with the single‐phase technique with sealer (group A) or the sectional technique without sealer (group B).
Barriers to diffusion of Ledermix® paste in radicular dentine
Authors: Abbott Paul Vincent , Hume Wyatt Roderic , Heithersay Geoffrey Sinclair
Published: April 2006

Abstract Freshly extracted human single‐rooted teeth with a single root canal were used to study the effects of 2 irrigation regimens and the effect of cementum on the diffusion of cortico‐steroid and antibiotic tracer molecules from Ledermix® paste placed in the pulp space. An irrigation regime that combined the use of 15% EDTAC and 1% NaOCl resulted in a significant increase in the permeation of the trace molecules through dentine compared with teeth that were irrigated with Savlon® solution. Mechanical removal of the cementum also resulted in a significant increase in the permeation of the trace molecules. This study demonstrated that neither the smear layer nor the cementum were complete barriers to diffusion. The data obtained appeared to be of clinical relevance and provided further understanding of the dynamics of drugs in tooth roots.
Etched metal prostheses to retain severely traumatized teeth in function
Authors: Chandler Nicholas Paul
Published: April 2006

Abstract Acid‐etch retained appliances of the Rochette and Maryland designs have proved valuable for the replacement of permanent anterior teeth in adolescents and adults. This article describes 2 patients for whom traumatized teeth of poor or “hopeless” prognosis were retained by splinting them to their neighbours with a Maryland‐type etched cast framework. Appearance and function have been maintained over several years, while the need for extraction and the provision of a conventional fixed prosthesis has been delayed or avoided.
Periapical reactions to calcium hydroxide‐containing sealers and AH 26® in monkeys
Authors: Tagger Michael , Tagger Etty
Published: April 2006

Abstract The long‐term effect on periapical healing (8‐14 months) of CRCS® and Sealapex® was compared with that of AH 26®. Vital pulpectomy and root canal filling by the hybrid ther‐momechanical method were performed in teeth of 3 young monkeys. Ten roots with CRCS, 10 with Sealapex and 7 roots with AH 26 were examined after demineralization and routine histological processing. Hematoxylin and eosin and Brown & Brenn staining for micro‐organisms were employed. Mild to severe inflammatory lesions were found at the apical foramina of the roots filled with AH 26 and CRCS. Most of the Sealapex specimens showed no inflammatory cells, except macrophages with sealer particles. A striking finding was a tendency towards apical obliteration with calcified tissue in roots filled with Seal‐apex, apparently following resorption of the sealer. Such a tendency was seldom observed with the other sealers. However, both AH 26 and Sealapex were irritating for a long time when pushed into bone. Despite the interesting results with Sealapex, additional research is needed before its use can be unconditionally recommended. This sealer has not yet been tested in infected cases and its ability to be resorbed, which is an advantage when it precedes replacement by calcified tissue, may become a disadvantage if it is not followed by apical obliteration.
The alkalizing properties of calcium hydroxide compounds
Authors: Stashle Hans Jörg , Pioch Thomas , Hoppe Wolfgang
Published: April 2006

Abstract Calcium hydroxide compounds are available in various forms, such as in aqueous suspensions or as cements, liners, pastes or filled resins. When such compounds are exposed to water, the calcium hydroxide dissociates and the pH value shifts to the basic. In this study the compounds Pulpdent®, Dycal®, Hydroxyline®, Gangraena Merz® and Prisma VLC‐Dycal® were subjected to analysis, including quantitative measurement of the amount and the chronological course of ion release following exposure to water, qualitative analysis of the alkalizing effects at the dentin surface and examination of antimicrobial properties. The results showed that calcium hydroxide compounds differed greatly. The strongest degree of ion release, combined with definite antimicrobial properties, was found for the aqueous calcium hydroxide suspension (Pulpdent). The cement (Dycal) demonstrated significantly weaker activity. The liner and the paste (Hydroxyline and Gangraena Merz), as well as the calcium hydroxide filled resin (Prisma VLC‐Dycal), were largely lacking in both ion release and antimicrobial properties under the experimental conditions.
Long‐term paresthesia following inadvertent forcing of sodium hypochlorite through perforation in maxillary incisor
Authors: Reeh Ernest S. , Messer Harold H.
Published: April 2006

Abstract During endodontic retreatment of a maxillary central incisor, a midroot buccal perforation was created, and sodium hypochlorite was inadvertently forced through the perforation into surrounding tissue. The consequences of this incident included immediate severe pain and swelling, with the subsequent development of a fistula, and in the long term (15 months), paresthesia of the floor and ala of the nose and the infraorbital area.
Experimental basis for the management of dental resorption
Authors: Pierce Angela M.
Published: April 2006

Abstract Current evidence indicates that the mechanisms by which the mineralized tissues, bone and dentin, are resorbed are similar. Osteoclasts and dentinoclasts are possibly indistinguishable cell types that both resorb mineralized substrata. The principles of treatment of both dental and osseous resorptions should therefore have much in common. This article discusses the basis of hard tissue resorption and explores the rationale for experimental approaches towards the management of dental resorption.
Pulp canal obliteration after Le Fort I osteotomy
Authors: Vedtofte Poul
Published: April 2006

Abstract A longitudinal study of 51 patients was carried out to determine the frequency of pulp canal obliteration (PCO) after Le Fort I osteotomy for the correction of dentofacial anomalies and to analyse pre‐ and peroperative factors influencing the development of PCO. PCO developed in 14 (2.3%) of 617 maxillary teeth followed for an average period of 28 months (range 11–59). The highest frequency of PCO was demonstrated in canines (6.0%) and premolars (4.4%). Total PCO was present in 9 teeth and partial PCO in 5 teeth. PCO was more frequent among teeth adjacent to a vertical interdental osteotomy than in teeth with no relation to a vertical osteotomy (p< 0.0001). Change in blood supply after the operation was suggested to be responsible for PCO, although it might have been effected by the combined surgical and orthodontic treatment. Long‐term follow‐up, including periapical radiographs, of teeth with PCO is suggested, as pulp necrosis may develop many years after surgery.
Dentin induction by implants of autolyzed antigen‐extracted allogeneic dentin on amputated pulps of dogs
Authors: Nakashima Misako
Published: April 2006

Abstract Implantation of autolyzed antigen‐extracted allogeneic (AAA) dentin matrix gelatin powder caused homeoinduction on amputated dental pulps. This event began with migration of spindle‐shaped mesenchymal cells into the cavity on the amputated pulp. This was followed by proliferation of undifferentiated large cells concomitantly with vascular invasion and attachment of spindle‐shaped cells and large cells to the AAA dentin. The adhering cells differentiated into osteodentinoblasts and/or preodontoblasts to form osteodentin matrix and predentin respectively. Osteodentinocytes and odontoblasts, then, formed osteodentin and tubular dentin. The healing of pulp dressed with inactivated AAA dentin using guanidine HCl was delayed. These results suggested that AAA dentin matrix powder may have chemotactic and mitogenic activity for undifferentiated mesenchymal cells and may provide a suitable scaffolding for fixation of these cells. Compartments of microenvironment formed by AAA dentin and the enveloping hard substances may play some role in differentiation into odontoblasts.
Similarities in the microfloras of root canals and deep periodontal pockets
Authors: Kerekes Kasmer , Olsen Ingar
Published: April 2006

Abstract Although not universally accepted, retrospective histological, roentgenological and microbiological studies have indicated that cross‐infection can occur between infected pulps and deep periodontal pockets. This review provides examples of similarities in the microfloras of these adjacent oral sites, supporting the idea that infection spreads from one site to the other. The organisms most often involved are probably bacteroides, fusobacteria, eubacteria, spirochetes, wolinellas, selenomonas, campylobacter, and peptostreptococci. Important qualities of cross‐infecting organisms may be the ability to survive in highly reduced environments and motility. Precautions should be taken to prevent in vivo seeding of such micro–organisms, particularly in compromised teeth and hosts.
Applicability of X‐ray computerized tomography in endodontics
Authors: Tachibana Hitoshi , Matsumoto Koukichi
Published: April 2006

Abstract This study was carried out to observe the teeth of the maxillary and mandibular bones in computerized tomographic (CT) scans. In addition to using CT images, a 3‐dimensional analysis was conducted for further visualization. The anatomical configurations of the teeth were clearly observed in the CT scans, as was the relation of the teeth to the periodontal tissues. Further, using CT scans made it possible to determine buccolingual and mesiodistal widths of teeth, and the presence or absence of root canal filling materials and metal posts. In addition, carious lesions of a certain size and expansions of the maxillary sinus and proximity to the roots were observed. The 3‐dimensional image analysis was interesting, but detailed observations could not be made with this technique.
Traumatic dental injuries in 3‐ to 13‐year‐old boys in Monterrey, Mexico
Authors: Sanchez Alicia Veronica , Garcia‐Godoy Franklin
Published: April 2006

Abstract The purpose of this retrospective study was to analyze, by age, the prevalence of traumatic injuries to primary and permanent incisors, and their distribution according to type in a group of boys from private schools in Monterrey, Mexico. The sample consisted of 1010 boys aged 3‐13 years enrolled in 4 private schools in the city. Garcia‐Godoy's classification for traumatic injuries was used. The prevalence of injuries was 28.4%; 72.2% of the 4‐year‐olds examined presented signs of traumatic dental injuries. Thirty‐seven percent of the 11‐year‐olds examined had evidence of traumatic dental injuries. The most common type of injury in the primary and permanent dentitions was enamel fracture (58.5% and 69.6%, respectively).
Experimental luxation injuries in immature rat teeth
Authors: Miyashin Michiyo , Kato Junji , Takagi Yuzo
Published: April 2006

Abstract The development of an experimental model in which a standardized traumatic injury is given to dental tissues of experimental animals is necessary to understand the tissue reactions of luxated human teeth. In this study we contrived a rat molar luxation device by which bilateral upper first molars are pushed horizontally toward the palate to cause a constant amount of dislocation. The pushing force is controlled with regard to strength, direction and duration. Using this device, molars of 3‐week‐old Wistar rats weighing 45‐60 g were luxated, and damage to the pulps and periodontal tissues was evaluated histologically. Every luxated tooth had approximately equal hemorrhage, cell degeneration, and irregularity of periodontal fibers in the palatal cervical region. In the buccal cervical and in the bifurcation regions, the periodontium suffered edema and hemorrhage. The periodontal fibers in these regions were elongated and, in some areas, torn. Periodontal hemorrhage was also observed at the distobuccal root apex. The severity and distribution of the tissue injury were nearly equal in almost all of the molars. Few alveolar bone fractures or root fractures were observed. From these results, it is concluded that a standardized luxational trauma can be delivered to rat molars by the use of this experimental method.
In vivo fractures of endodontically treated posterior teeth restored with enamel‐bonded resin
Authors: Hansen Erik Keith , Asmussen Erik
Published: April 2006

Abstract The cumulative survival rate of 190 endodontically treated posterior teeth were assessed in a retrospective study; all teeth had an MO/DO or an MOD cavity restored with a composite resin without cuspal overlays after previous acid‐etching of the enamel. In contrast to our previous study on endontically treated posterior teeth restored with amalgam, the survival rate of the MOD resin‐restored teeth was equal to that of MO/DO teeth. Teeth restored with a light‐activated resin had a much lower survival rate than teeth restored with a chemically‐activated material, the cause presumably being that the light‐activated resins were insufficiently irradiated. Nearly 25% of the teeth had been restored with a microfilled resin for anterior use and these teeth had a lower survival rate than had teeth restored with a macrofilled or hybrid resin. It was also found that a beveling technique did not decrease the fracture rate while the use of an intermediate layer of low‐viscosity resin resulted in a significant improvement.
Tooth splinting: a review of the literature and consideration of the versatility of a wire‐composite splint
Authors: Oikarinen Kyösti
Published: April 2006

Abstract The principles of tooth luxation splinting have been changed since the animal and human tests conducted in the early 1970s showed that masticatory stimulus promotes healing of luxated teeth and normally exerted occlusal forces are able to prevent and eliminate small resorption cavities on the root surface. It has also been shown that fixation of only one week is enough to achieve the clinical healing of repositioned teeth. Apart from esthetic and hygienic components, present‐day demands on tooth fixation techniques also include ease of construction and removal and the use of devices which allow slight movement of the fixed teeth. This paper presents the history of tooth splinting, our present‐day knowledge of the subject, and introduces various splinting techniques. The wide range of indications for a flexible wire‐composite splint are analyzed more thoroughly.
Epinephrine permeation across dentin in vitro
Authors: Ciarlone A. E. , Tao L. , Ziemer D. , Pashley D. H.
Published: April 2006

Abstract The permeation of epinephrine across human dentin discs was studied in vitro. Permeation was measured across dentin of two different thicknesses, with and without the presence of smear layers. Epinephrine was readily detected at the earliest measured time (10 min) and reached peak concentrations between 30 and 50 min. Epinephrine flux (concentration multiplied by the volume of the effluent per min) increased with decreasing thickness of the discs and increased significantly with the removal of the smear layer. The T1/2 (half‐time in min necessary to reach steady‐state diffusion of epinephrine) decreased as dentin thickness was reduced and fell further in the absence of the smear layer. This study suggests that the permeation of epinephrine across dentin is inversely related to dentin thickness and retarded by the presence of a smear layer. Also, the topical use of 1 mg/ml epinephrine produced therapeutically useful drug concentrations, but the rate of permeation was relatively slow.
Dynamic resistance of teeth: technical considerations and applications of an experimental device
Authors: Fabra‐Campos Hipòlito , Dalmases Francisco J. , Buendia Mateo , Cibrian Rosa M.
Published: April 2006

Abstract Tooth fracture by impact is the most common cause of fracture in human incisors. We have designed an experimental system to measure the dynamic fracture force of teeth in vitro, and initial results obtained from a sample of healthy, recently removed human incisors are reported. The method was reproducible and reliable, and the results provide a baseline for studies evaluating the effect of endodontic procedures on the dynamic fracture force of teeth.
Tissue reactions after experimental luxation injuries in immature rat teeth
Authors: Miyashin M. , Kato J. , Takagi Y.
Published: April 2006

Abstract Immature permanent teeth often develop complications after luxation injuries. The pathology and the degenerative processes of the complications, however, are not well understood. In this study, we histologically examined the long–term reactions of immature rat teeth after standardized luxation injuries delivered in our previously developed experimental model. The upper first molars of 3‐week‐old male Wistar rats weighing 50‐60 g were pushed horizontally toward the palate to cause a constant amount of dislocation. The follow‐up changes of the luxated molars were studied up to 56 days after the trauma. Soon after the trauma, the periodontium had irregular fibers, degenerated cells, hemorrhage and edema in various places. After 12 h, a cell free area appeared in the palatal periodontium. In the alveolar bone and on the surface of the root, resorption occurred one day and 5‐7 days after injury respectively. Although the damage in the periodontium and alveolar bone was gradually repaired, the root resorption, especially in the palatal cervical region, continued throughout the experimental period. In the most cases, the dental pulp did not seem to be damaged immediately after the trauma. By the 3rd day after injury, however, displacement of odontoblasts into the dentinal tubules was observed in many teeth. Moreover, formation of irregular dentin was observed in some teeth after 7 days. These changes of the pulp tended to disappear in the later stages of the experiment.
Effects of the penetration of a root canal filling material into the mandibular canal. I. Tissue reaction to the material
Authors: Kawakami T. , Nakamura C. , Eda S.
Published: April 2006

Abstract The root canal filling paste Vitapex (Neo Dental Chemical Products Co., Tokyo), made of calcium hydroxide and iodoform with the addition of silicone oil, was experimentally introduced into the mandibular canals of 29 dogs. Tissue reactions to the paste were examined by radiography, histopathology, and electron microscopy. These examinations revealed that the paste was phagocytosed by macrophages and, in general, was gradually resorbed over time. The paste was also found to cause heterotopic calcification and/or ossification within the area of original penetration.
Entrapped air and its effects on dye penetration of voids
Authors: Oliver C. M. , Abbott P. V.
Published: April 2006

Abstract This study was conducted to determine the effect of entrapped air on the ability of methylene blue dye to penetrate known and measurable voids. Thirty six capillary tubes were sealed at one end and had standardized voids created within the lumen. Three equal groups of 12 test specimens and 4 controls were subjected to dye penetration by the methods of passive immersion for 7 days, centrifuging at 3,000 rpm for 5 minutes and immersion in a vacuum of 26 mm of mercury for 5 minutes. Measurement of linear dye penetration was made by removing shavings from the sealed end until dye could be observed. Negative controls showed no dye penetration and positive controls showed complete penetration. The vacuum method showed 100% penetration in all cases, while centrifuging had a mean of 91.7 ± 8.7% penetration and passive immersion had a mean of 20.7 ± 5.4% penetration. This study demonstrates that passive dye leakage studies are unreliable and very variable. The vacuum method whereby all entrapped air is removed is the most reliable method for dye penetration studies.
Pulp capping of immature teeth with anatomic anomalies
Authors: Trope M. , Rabie G. , Tronstad L.
Published: April 2006

Abstract This case report describes the treatment of two immature teeth with anatomic anomalies which created plaque retentive areas and in one case occlusal disturbance. Periodontal and pulpal consequences were inevitable. Reshaping of the teeth was carried out which as expected led to exposure of the pulp in both instances. Pulp capping was then performed under aseptic conditions. The vitality of the teeth was maintained and continued root development was observed.
Histometric study of the effect of occlusal alteration on periodontal tissue healing after surgical injury
Authors: ElDeeb Mahmoud E. , Andreasen Jens O.
Published: April 2006

Abstract The effect of occlusal alteration upon healing of the periodontium after surgical injury was studied in 62 male Wistar rats, nine weeks of age. An osteotomy was made with a bur through the vestibular bone plate, the periodontal ligaments and into the superficial part of the root surface of the first mandibular molar. In the same session, the occlusion of the antagonistic tooth was altered in the experimental groups by either placing a high amalgam restoration, grinding, or extraction. The occlusion in the control group was unaltered. The rats were killed 70 days after surgery, and examined histologically. A histometric registration of the periodontal repair revealed a significant narrowing of the periodontal ligament width in the non‐occluding teeth, as well as signifiant thickening of cementum at and above the surgical cavity site. The hypo‐ and hyper‐occluding teeth did not show significant changes as compared to the controls.
Conservative management of a combined endodontic‐orthodontic lesion
Authors: Rotstein Ilan , Engel Gabriel
Published: April 2006

Abstract Pulp injury may occur during orthodontic tooth movement particularly in previously traumatized teeth. Therefore the management of such cases requires specific therapeutic considerations. An extensive periradicular lesion was detected in an orthodontically treated maxillary incisor with an uncertain history of a previous traumatic incident. Conservative endodon‐tic therapy resolved the periradicular lesion thus enabling the orthodontic treatment to continue uneventfully. It is essential to closely monitor the patients undergoing orthodontic treatment and those who are in retention, particularly if a history of trauma is suspected.
Effect of bleaching time and temperature on the radicular penetration of hydrogen peroxide
Authors: Rotstein Ilan , Torek Yarom , Lewinstein Israel
Published: April 2006

Abstract Extracted human premolars were treated endodontically and bleached intracoronally. The teeth were bleached with 30% hydrogen peroxide for periods of 5, 20, 40 and 60 min at temperatures of 24°C, 37°C and 47°C. A correlation for both bleaching time and temperature and the radicular penetration of hydrogen peroxide was found. No penetration was found after 5 min bleaching at any of the temperatures tested. Prolonging the bleaching time after 5 min increased the hydrogen peroxide penetration at each of the temperatures tested. A rise in the bleaching temperature also increased the hydrogen peroxide penetration although not significantly for all tested periods. It is therefore suggested to minimize the bleaching time and temperature when hydrogen peroxide is used as the oxidizing agent. Bleaching should be limited to separate 5‐min periods rather than being performed over a long continous period.
Follow‐up study of endodontic status in an adult Swedish population
Authors: Petersson K. , Håkansson R. , Håkansson J. , Olsson B. , Wennberg A.
Published: April 2006

Abstract The purpose of this study was to examine changes in the endodontic status of selected teeth in a population over time, in order to get a long‐term perspective of endodontically treated teeth. A random sample of the adult Swedish population was selected in 1974 and offered a clinical and radiographic examination. Eleven years later 351 of the selected persons attended a follow‐up examination (1985). In radiographs, covering the mandibular premolar and molar regions, the status of 1974 was directly compared, tooth by tooth, with the status of 1985. The results showed that a number of endodontically treated teeth with an apical periodontitis healed during the observation period. During the same period, approximately the same number of endodontically treated teeth presented with a new apical periodontitis. This finding suggested that cross‐sectional studies could provide reliable information on the long‐term success rate of endodontic treatment at the population level. The periapical lesions that persisted or developed during the observation period were strongly related to incomplete root canal obturation, which is in agreement with observations in follow‐up studies from teaching and specialist clinics.
Endodontic therapy as an adjunct for treatment of juvenile periodontitis: case report
Authors: Sommer Maurice , Yaffe Avinoam
Published: April 2006

Abstract The four first permanent molars in a 16‐year‐old girl with juvenile periodontitis were treated by selective grinding, tooth eruption, conventional periodontic treatment and endodontic therapy. The endodontic treatment was carried out as an elective procedure under ideal conditions, thereby preempting the emergency treatment which would have been necessary following occlusal reduction. The two‐year follow‐up examination showed successful resolution of the original condition.
Sealing ability of sectional injection thermoplasticized gutta‐percha technique with varying distance between needle tip and apical foramen
Authors: Veis A. , Lambrianidis T. , Molyvdas I. , Zervas P.
Published: April 2006

Abstract The purpose of this investigation was to evaluate the influence of the distance of the needle tip from the apical foramen on the apical seal and the length control of the root filling material when thermoplasticized gutta‐percha is injected using a sectional injection technique. Ninety‐nine human single‐rooted mandibular incisors and permanent premolars with straight canals were divided into three equal Groups A, B and C. In Group A the teeth had relatively the wider root canal, in Group C the narrowest, while in Group B root canal size was intermediate. The root canals of all teeth were prepared with a step‐back technique. Roots of Group A were instrumented to a Size 70 4 mm short of the working length, while roots of Groups B and C to a Size 70 6 mm and 8 mm short of the working length, respectively. The teeth of all groups were covered with aluminium foil and embedded in acrylic blocks. After the placement of sealer (Roth 811) the root canals of all teeth were obturated with injection‐molded thermoplasticized gutta‐percha using a three‐stage sectional technique. The roots remained in India ink for three days and then cleared by successive immersion in nitric acid, ascending grades of alchohol and finally in xylene. The linear dye penetration and the linear apical underextension of the root canal filling were measured by two independant examiners under a stereo microscope. There was no significant difference in the linear dye leakage between the groups. However, because of the zero value of linear underextention in Group A, significant difference was found between Group A vs B and A vs C, while no statistically significant difference was found between B and C groups.
Morphology of the mineralizing front and observations of reparative dentine following induction and inhibition of dentinogenesis in the rat incisor
Authors: Kirk E. E. J. , Meyer M. J.
Published: April 2006

Abstract An extra oral approach was made to 26 pairs of Wistar rat incisors and a small bur used to expose the pulps which were then dressed with either calcium hydroxide paste (Pulpdent) zinc oxide‐eugenol cement (Kalzinol) or a triamocino‐lone acetonide/tetracycline containing cement (Ledermix). Animals were sacrificed at 7 days, incisors removed, a window cut to the pulp opposite the site of exposure, soft tissues removed with 7% NaOCl for 30 minutes before teeth were dehydrated in graded concentrations of acetone and gold coated for examination under SEM. Calcium hydroxide produced rapid complete repair with a remarkably regular formation of calcospherites, except for a zone of relative inhibition perforated by nutrient canals at the periphery of each lesion. Both zinc oxide‐eugenol and triamcinolone acetonide cements inhibited both bridging of the defect created by the exposure and dentine formation in the surrounding pulpal wall. Data was grouped according to the degree of hard tissue repair. The results were statistically significant (Chi‐square p0.001). This method demonstrated qualitative and quantitative differences in the repair process resulting from chemical variations in the dressings applied.
Effect of cervical coating of ethyl cellulose polymer and metacrylic acid copolymer on the radicular penetration of hydrogen peroxide during bleaching
Authors: Rotstein Ilan , Lewinstein Israel , Zuwabi Ottman , Stabholz Adam , Friedman Michael
Published: April 2006

Abstract Extraradicular leakage of oxidizing agents during bleaching is an undesirable event and thus need to be prevented. The effect of external cervical coating of ethyl cellulose (EC) and metacrylic acid copolymer (MAC) on the radicular penetration of hydrogen peroxide during intracoronal bleaching was examined. Single rooted human premolars extracted for orthodontic reasons were used. The cementum covering the cemento‐enamel junction was mechanically removed and the teeth treated endo‐dontically and bleached with 30% hydrogen peroxide. Radicular hydrogen peroxide penetration was measured before coating the teeth and after applications of 1–3 layers of EC or 3 layers of MAC external cervical coatings. It was found that the radicular penetration of 30% hydrogen peroxide was related to the number of layers of cervical EC coatings. Application of one layer of EC did not reduce the hydrogen peroxide penetration. Two and three layers of EC reduced the hydrogen peroxide penetration by 38% and 85% respectively. Three layers of MAC reduced the radicular hydrogen peroxide penetration in 83%. Statistically, a highly significant difference was found between the teeth coated with three layers of either EC or MAC and the noncoated teeth (p< 0.001). It was concluded that application of ethyl cellulose or metacrylic acid copolymer to exposed cervical root surfaces may effectively prevent extraradicular leakage of bleaching agents.
Profiling of Propionibacterium acnes recovered from root canal and blood during and after endodontic treatment
Authors: Debelian G. J. , Olsen I. , Tronstad L.
Published: April 2006

Abstract This report describes the first results of an ongoing study of bacteremia after endodontic treatment of teeth with Asymptomatic apical periodontitis. After access cavity preparation, microbiological samples were taken from the root canal under aseptic conditions in 4 single‐rooted teeth in 4 patients. In treatment of 2 of the patients, the first 3 reamers (sizes 15‐25) were deliberately used to a level 2 mm beyond the apical foramen. In 2 patients the instrumentation ended inside the root canal 1 mm short of the apical foramen. Blood samples were taken from the patients during the endodontic instrumentation and 10 min after the treatment was completed. Using lysis‐filtration under anaerobic conditions, the blood was passed through a cellulose membrane filter. The filters as well as the root canal samples were incubated using an anaerobic technique. Anaerobic bacteria were isolated from all root canals. In the 2 patients where overinstrumentation had occurred, Propionibacterium acnes was recovered both from the root canals and from the blood samples taken during and after the treatment had been completed. Biochemical profiles, antibiotic susceptibility tests and electro‐phoresis of soluble proteins revealed that Propionibacterium acnes isolated from the root canal and blood samples were identical within patients, but varied between patients. Facultative anaerobic bacteria including Streptococcus sanguis were recovered from only one root canal sample and not from the blood samples.
Ectopic eruption of a maxillary canine following trauma
Authors: Symons Anne L.
Published: April 2006

Abstract Traumatic events at an early age may lead to developmental dental anomalies and ectopic tooth eruption. A case is reported in which a traumatic injury at two months of age resulted in the development of supernumerary teeth in the upper right premaxillary region. The maxillary canine ectopically erupted or transposed into the space left by the missing central incisor and eliminated the need for a prosthesis in this region.
Generalized “complete” calcific degeneration or pulp obliteration
Authors: Piattelli Adriano
Published: April 2006

Abstract Extensive calcification of the pulp is a pathologic condition that occurs as an answer to various factors (trauma, caries, periodontal disease). The increase in the amount of calcification may lead to partial or complete radiographic, but not microscopic, obliteration of the pulp chamber and root canals. Complete calcific degeneration (pulpal obliteration) may be found in two forms, generalized or localized. The generalized form which is presented in the present case report is probably part of the aging process.
Methods for removing metal obstructions from the root canal
Authors: Hülsmann Michael
Published: April 2006

Abstract The removal of metallic obstructions is an important part of endodontic retreatment procedures and encounters a number of serious problems. Sometimes removal procedures are extremely easy and can be performed in rather short time, but often it is a very tedious and time‐consuming operation with a high number of failures, especially with fractured instruments. Using special devices such as the Masserannkit, the Canal‐Finder‐System, or ultrasonic systems some fractured instrument cases can be managed successfully. The retreatment of dowel‐obturated root canals or failing silver cone cases has a good prognosis and a fairly good success rate. The Masserannkit, post pullers, the Canal‐Finder‐System and ultrasonic systems have been shown to be helpful devices in removal of root posts and silver cones. Additionally a large number of special devices and techniques for the removal of metal obstructions from the root canal have been described in the literature and will be critically reviewed.