bluuebunny/crossref_metadata_2025 huggingface dataset:
An analysis of breakage of ultrasonic files during root canal instrumentation
Authors: Ahmad Majinah
Published: April 2006

Abstract The incidence of fracture of Cavi‐Endo ultrasonic K‐files during ultrasonic root canal preparation was evaluated. In addition, the appearance and the sites of fractures were examined in relation to the nodal points on the file. The displacement amplitudes and the hardness of the files were quantified to determine their relationship to fracture. It was observed that the files exhibited a low incidence of fracture, which was of the brittle type and occurred at the apical ends. The displacement amplitude and the hardness of the files did not appear to influence the incidence of fracture.
Vertical crown‐root fracture of the mandibular first primary molar in a one‐year‐old child
Authors: Morisaki Ichijiro , Kitamura Kyoichi , Ooshima Takashi , Sobue Shizuo
Published: April 2006

Abstract A vertical crown‐root fracture of the mandibular first primary molar in a 21‐month‐old child is presented. The mandibular primary first molar was fractured vertically and split into 2 pieces. The tooth fracture had not been noticed for about 5 months after the accident, and the tooth was left without any treatment. The pulp tissue of the mesial root maintained its vitality, but the distal root was nonvital.
A simple model for evaluating relative toxicity of root filling materials in cultures of human oral fibroblasts
Authors: Arenholt‐Bindslev Dorthe , Hörsted‐Bindslev Preben
Published: April 2006

Abstract Standardized test tubes filled with freshly mixed root filling materials (AH26, CRCS, N2, Kloroperka NØ, ZOE cement and 2 experimental cements, ECI and ECII) were transferred into tissue culture flasks. Normal human oral fibroblasts were seeded in the flasks. Morphological cell changes were studied up to 15 days after seeding. The size of cell‐free zones around the test tubes and the total cell number per culture flask were calculated after 5, 10 and 15 days. The findings showed N2 cement to be by far the most toxic material at all observation periods, whereas no toxic reactions could be seen in relation to tubes filled with Kloroperka NØ. Compared with the 5‐clay observation period, some cell recovery was observed around test tubes with AH26 and ECII, whereas almost full cell recovery was found around test tubes with CRCS, ZOE and ECI. It was concluded that the present model, which allows long‐term observations of human cellular reactions to dental materials, can be used as a simple and relatively cheap screening test for initial toxicity testing of dental materials.
Supra‐alveolar periodontal healing of auto‐ and allotransplanted teeth in monkeys
Authors: Groisman Mario , Schwartz Ole , Andreasen Jens Ove , Attström Rolf
Published: April 2006

Abstract Although intra‐alveolar healing of allotransplanted teeth often shows pathological changes due to rejection of the tooth graft, previous clinical findings seem to indicate that the supra‐alveolar part of the allografts heals differently, which is of significant prognostic value. The aim of the present study was to determine the healing of the cervical part of the periodontium of auto‐ and allotransplanted mature teeth in monkeys. In 4 adult, immunologically unmatched, green vervet monkeys 16 mature permanent maxillary and mandibular incisors were extracted, endodontically treated and either auto‐ or allotransplanted; 8 untreated neighbouring incisors served as controls. Block biopsies including part of the tooth and the adjacent vestibular tissues were obtained after a healing period of 8 weeks. The biopsies were decalcified in EDTA and embedded in Epon. In semi‐thin sections (1.5 μm) the morphology of the supra‐alveolar periodontal tissues was analysed in the light microscope. The orientation of the connective tissue fibres close to the root surface was found to be more parallel to the root surface of allotransplants compared with autografts, while in the control teeth the fibres were generally oriented perpendicular to the root surface. Resorption of the root was seldom found in the supra‐alveolar portions of any of the transplanted teeth. The junctional epithelium had migrated slightly apically onto the root surfaces of allotransplanted teeth. The gingival connective tissue adjacent to allotransplanted teeth showed a significantly increased number of lymphocytes compared with autografts and controls. Gingival healing of allotransplanted teeth only differed slightly concerning the orientation of inserting fibres, the number of lymphocytes surrounding the graft and the position of the junctional epithelium, compared with autografts and control teeth.
Pulpal response to an anhydrous glass ionomer luting cement
Authors: Tobias R. S. , Plant C. G. , Rippin J. W. , Browne R. M.
Published: April 2006

Abstract This investigation was designed to study the pulpal responses to Aquacem®, an anhydrous glass ionomer luting cement, and to compare the results with those previously obtained for a conventional glass ionomer luting cement, Chembond®. The study was carried out according to the BSI (1980) recommendations for testing restorative materials in vivo. Aquacem caused more pulpal inflammation than the control material, Kalzinol®, though by an indirect mechanism. The statistical model demonstrated a significant association between bacterial presence within the experimental cavity and pulpal inflammation. The type of restorative material has no direct association with the degree of inflammation, but the model suggests that it exerts an indirect influence via its antibacterial properties and hence its influence on microbial microleakage.
Replacing resorbed maxillary central incisors with mandibular premolars
Authors: Oikarinen Kyösti
Published: April 2006

Abstract A case report is presented on autotransplantation of a lower premolar into the upper central incisor area. A traumatized upper central incisor lost because of external root resorption was replaced by a premolar transplant taken from a crowded mandibular arch. The transplant showed excellent adaptation and the periapical inflammation noticed a few years after the operation was treated successfully with apicectomy.
Adhesion of light‐cured composite resin to bleached and unbleached bovine dentin
Authors: Torneck C. D. , Titley K. C. , Smith D. C. , Adibfar A.
Published: April 2006

Abstract Cylinders of small‐particle light‐cured composite resin were bonded to the superficial dentin layer of young bovine incisors that had previously been subjected to 4 different treatments: 1) immersed in 35% hydrogen peroxide for 60 min, then etched with 37% phosphoric acid gel for 60 s; 2) immersed in saline for 60 min, then etched with 37% phosphoric acid gel; 3) etched with 37% phosphoric acid gel for 60 s, then immersed in 35% hydrogen peroxide for 60 min; and 4) etched with 37% phosphoric acid gel, then immersed in saline for 60 min. Specimens were stored in water at 37°C for 1 and 7 d prior to tension and shear testing. A total of 128 teeth were tested: 8 teeth in each group, for each day and for each test. No measurable adhesion of resin to peroxide‐treated dentin was observed and statistical analysis of the test results indicated that this represented a highly significant reduction in the bond strength as compared with values obtained when resin bonded to saline‐treated dentin was tested. SEM examination of randomly selected fracture test specimens indicated that the bond failure was both cohesive and adhesive in nature, suggesting that peroxide treatment adversely affects the setting of bonding resin and its adhesion to a filled resin.
Shape of the root canal after ultrasonic instrumentation with K‐Flex files
Authors: Ahmad Majinah
Published: April 2006

Abstract This study investigated the feasibility of using K‐Flex files with the Cavi‐Endo ultrasonic unit. The effectiveness of the K‐Flex files in shaping canals was compared with the ultrasonic Cavi‐Endo K‐files. Simulated curved canals in clear resin blocks were instrumented ultrasonically using the 2 file types. Pre‐ and postinstrumentation photographs were taken and the following were evaluated: apical and coronal areas, the incidence of the narrowing of the canals coronal to the apical transport (elbows). Displacement amplitude measurements were carried out in order to see any relationship between the incidence of elbows and displacement amplitudes of the files. The results indicated that the K‐Flex files were more efficient than the ultrasonic K‐files and resulted in less elbow formation. No direct relationship was observed between displacement amplitudes and the incidence of elbow formation. It is suggested that the manufacturers of ultrasonic units consider different file designs.
An experimental model for cervical resorption in monkeys
Authors: Brosjö Marianne , Anderssén Karin , Berg Jan‐Olov , Lindskog Sven
Published: April 2006

Abstract The aim of the present study was to develop an experimental model for cervical root resorption and to study the significance of the junctional epithelium for the prevention of cervical resorption. Marginal experimental cavities covered by a thin plastic foil presented a dentin surface devoid of epithelial coverage. The dentin surface displayed numerous resorption cavities containing a cell‐rich granulation tissue with a moderate chronic inflammation. Cavities to which no plastic foil had not been added, however, were all covered by a thin squamous epithelium. At no level did any of the originally denuded dentin surfaces come in contact with mucosal or periodontal connective tissue. The present study indicated that an incomplete epithelial coverage of a marginal dentin surface in combination with marginal gingivitis or periodontitis is sufficient to maintain a progressive cervical resorption.
Microbiological monitoring and results of treatment of extraradicular endodontic infection
Authors: Tronstad Leif , Kreshtool Daniel , Barnett Frederic
Published: April 2006

Abstract This report describes a case where aggressive treatment of a tooth with Asymptomatic apical periodontitis was at first unsuccessful. The reason for the failure of the treatment was an established infection extraradicularly in the periapical lesion that only partly could be influenced by local and systemic antimicrobial treatment. The effectiveness of this treatment was monitored by microbiological sampling from the root canal, a fistulous tract, and, in the end, directly from the periapical lesion. The results of the monitoring were meaningful. They showed that the bacterial flora could be influenced, but not eliminated, and were strongly suggestive of an established infection outside the root. Scanning electron microscopy confirmed the presence of a bacterial plaque on the surface of the root tip removed during the final surgical‐endodontic treatment of the tooth. Following apicoectomy and removal of the periapical lesion, repair was uneventful with the formation of new bone in the surgical cavity after 6 months.
Secondary dentin in replanted teeth — a histometric study
Authors: Breivik Martin , Kvam Einar
Published: April 2006

Abstract To quantify the secondary dentin formation in replanted teeth, 16 human premolars with a postoperative observation period of 6, 12 and 24 weeks were studied histometrically. In spite of marked intra‐ and interindividual variations, a regression analysis revealed a significant correlation (r=0.70) between observation time and the quantity of secondary dentin in the coronal pulp registered by histometry. A comparison with a previous semiquantitative interpretation of the same material showed that the histometric method was more accurate.
Measurements of temperature generated by ultrasonic file in vitro
Authors: Ahmad Majinah
Published: April 2006

Abstract The temperature rise of the irrigant in the root canal during free vibration of the ultrasonic file was studied in vitro in 10 human teeth. The mean temperature rise was found to be 0.6°C. The minimal temperature increase may not significantly contribute to the effectiveness of ultrasonic root canal instrumentation.
Evidence for an inhibitor of osteoclast attachment in dentinal matrix
Authors: Wedenberg C. , Yumita S.
Published: April 2006

Abstract The ability of osteoclasts to colonize in vitro different preparations of dentin extracted with guanidinium hydrochloride (GuHCl) was studied in order to establish morphological evidence for an extractable inhibitor of osteoclast spreading within dentin. Osteoclasts were isolated from neonatal rats and seeded onto pieces of fully mineralized dentin, demineralized dentin and predentin extracted with GuHCl. Osteoclasts were also seeded onto unextracted tissues. The results were evaluated with scanning electron microscopy. Osteoclasts colonized and resorbed fully mineralized dentin, whereas clastic cells were not observed on unextracted demineralized dentin and predentin. In contrast to this, osteoclasts attached and spread on demineralized dentin and predentin extracted with GuHCl. It was concluded that the non‐collagenous organic component of dentin contains an extractable inhibitor of osteoclastic attachment and spreading. It is tempting to speculate that the inhibitor may be responsible for the naturally occuring resistance of dentin to resorption.
Prevalence of previous endodontic treatment, technical standard and occurrence of periapical lesions in a randomly selected adult, general population
Authors: Ödesjö Björn , Helldén Leif , Salonen Lars , Langeland Kaare
Published: April 2006

Abstract A random sample of 967 subjects selected from the total population in a Swedish county were examined radiographically regarding prevalence and quality of endodontic treatment and occurrence of periapical lesions. The relationship between the technical standard of endodontic treatment and the occurrence of periapical lesions was also analyzed. Of the selected individuals, 95% attended examination (751 dentate and 169 edentulous individuals). Of the 17,430 teeth examined, 1,492 (8.6%) were endodontically treated. Approximately 70% of the treated root canals were inadequately obturated; 10% showed excess of root filling beyond the apex. The prevalence of periapical lesions was 2.9%, and 24.5% of the endodontically treated roots demonstrated periapical lesions. Root fillings ending more than 2 mm from apex had a significantly lower frequency of periapical lesions than root fillings ending within 2 mm of the apex. No difference in the frequency of periapical lesions was found between properly and improperly obturated root canals. Excess of root filling material beyond the apex was related to a significantly higher frequency of periapical lesions.
Dentine hypersensitivity: a review
Authors: Collaert Bruno , Fischer Carla
Published: April 2006

Abstract Dentine hypersensitivity is a relatively common pain condition. Local pulpal inflammation, traumatic oral hygiene and dietary habits have been considered in the etiology of dentine hypersensitivity. Dentine hypersensitivity is probably caused by a change in fluid flow in the dentinal tubules, which in turn excites the nerve endings located at the pulp‐dentine border. Consequently, treatment success would depend on the prevention of fluid flow across the dentinal tubules (sodium fluoride, stannous fluoride, sodium monofluorophosphate, strontium chloride, sodium citrate, potassium oxalate, and resins/adhesives), or on the desensitization of the nerve endings located at the pulp‐dentine border (potassium nitrate). Although a wide variety of treatment methods have been available, clinical data is characterized with ambiguity, warranting further research of the factors which could possibly be implicated in the occurrence of dentine hypersensitivity.
Leukotrienes: their possible role in pulpal and periapical diseases
Authors: Torabinejad Mahmoud , Cotti Elisabetta , Lessard George
Published: April 2006

Abstract Leukotrienes play an important role in inflammation and its sequelae such as pain, swelling, and bone resorption. This review covers, their history, structure, synthesis, metabolism, biological effects, inhibitors, antagonists, and their possible role in pathogenesis of pulpal and periapical disease.
Dental injuries: “first aid” knowledge of Southampton teachers of physical education
Authors: Newman Louise J. , Crawford Peter J. M.
Published: April 2006

Abstract A total of 66 teachers of physical education within the Southampton telephone area responded to a postal questionnaire related to their knowledge of the first aid treatment of dental injuries. In a case study investigating tooth fracture, 64% gave an appropriate answer. In a second case study relating to avulsion (loss) of a permanent tooth, 43% gave an appropriate answer. There was an unclear relationship between the point in their careers at which teachers had received first aid training and the accuracy of their responses. There is a need for further information in this area.
Clinical evaluation of pulp and dentine sensitivity after supragingival and subgingival scaling
Authors: Fischer C. , Wennberg A. , Fischer R. G. , Attstrom R.
Published: April 2006

Abstract The exposure of dentinal tubules by the removal of root cementum on scaling procedures has been proposed to be a source of pulp injury and to cause dentine hypersensitivity. The aim of this study was to evaluate the sensitivity of the pulp and dentine after supragingival and subgingival scaling. Eleven patients with periodontally diseased mandibular incisors were selected. The subjects were divided into two groups according to marginal bone loss. The pulp sensitivity was evaluated by an electric pulp test. Dentine sensitivity was evaluated with two forms of controlled stimulations (probe and air‐jet) and with a questionnaire. No changes in pulp sensitivity were found after scaling, but a clinically significant increase in dentine sensitivity to probe and/or air stimuli was observed in 6 patients. Five of these were also sensitive to daily life stimuli. A natural mechanism of desensitization seemed to have occurred two weeks after subgingival debridement. This study showed that supragingival and subgingival scaling might cause a more or less transient occurrence of dentine hypersensitivity.
Dental trauma in children: a survey
Authors: Perez R. , Berkowitz R. , Mcllveen L , Forrester D.
Published: April 2006

Abstract The purpose of this investigation was to determine the type and prevalence of injuries presenting to the pediatric dental service of the Child Nat Med Ctr. During the 12 months survey, 227 patients presented. This patient group consisted of 159 males (M) and 68 females (F) (2.34 M to 1.0 F); 96 (62 M, 34 F) were <5 y age; 85 (64 M, 21 F) were 5 to 12 y age; 46 (33 M, 13 F) were ≥ 13 y age. The leading cause of injury was falls (105/227; 46%). Approx 50% (115/227) of the injuries occurred between May and September; 132 children sustained soft tissue injury (88 intraoral; 20 extraoral; 24 intra and extraoral); 61 permanent teeth were fractured in 44 children; 36 primary teeth were fractured in 31; 133 permanent teeth in 63 and 148 primary teeth in 79 patients sustained a displacement type of injury; 13 presented with an alveolar fracture. These observations extend earlier information regarding the epidemiology of dental injuries in childhood.
Prevalence of apical periodontitis, crowned teeth and teeth with posts in a Swedish population
Authors: Eckerbom Mats , Magnusson Tomas , Martinsson Thore
Published: April 2006

Abstract A longitudinal radiological study was carried out of 200 consecutive patients in a Swedish population. The aims of the investigation were to study the prevalences of crowned teeth, pontics and posts on two occasions with an interval of 5–7 years and, furthermore, to study apical periodontitis in connection with teeth with crowns and posts to see if such treatments affected this prevalence. 417 (mean 2.1) teeth were crowned at the first examination and 529 (mean 2.6) at the second. For pontics, the corresponding figures were 93 (mean 0.5) and 141 (mean 0.7). Crowns and pontics were more common in the upper jaw. 59.4% of the endodontically treated teeth had posts at the first examination and 64.4% at the second. 34.5% of the 255 teeth with apical periodontitis found at the first examination and 41.0% of the 268 at the second were in connection with posts. It was concluded that both crowns and pontics were common treatment procedures in the studied population. Crown therapy did not seem to impair the apical status while teeth with posts more often had apical periodontitis than other teeth and, furthermore, teeth with screw posts were lost more frequently than other teeth.
Medication of the dental pulp: a review and proposals
Authors: Ciarlone Alfred Edward , Pashley David Henry
Published: April 2006

Abstract For years, dentists have desired to treat the intact dental pulp. Since it is well‐known that many substances, including some drugs, arc capable of permeating dentin, we believe it is possible to treat certain types of pulpitis by applying drugs at the base of cavity preparations. Useful drugs include local anesthetics to block pain transmission, glucocorticoids or non‐steroidal anti‐inflammatory agents (NSAIA) to treat inflammation. NSA1A or narcotic analgesics for pain control, and antibiotics to treat infection. The literature is reviewed and proposals are presented to study medication of the dental pulp.
Effect of trichloracetic acid on the microhardness and surface morphology of human dentin and enamel
Authors: Lewinstein Israel , Rotstein Han
Published: April 2006

Abstract Trichloracetic acid is recommended For the treatment of external cervical root resorption. The present study examined the effect of 90% trichloracetic acid on the microhardness and surface morphology of human dentin and enamel. Intact extracted human teeth were sectioned and embedded in acrylic resin. Each tooth was grinded and highly polished exposing a flat surface of den Lin and enamel. The teeth were treated with 90% trichloracelic acid for 30, 60 and 90 s. Vicker's microhardness of the dentin and enamel was assessed for each tooth before and after each treatment. In addition the surface morphology of a trichloracetic add treated tooth was examined via SEM. The results showed that 90% trichloracelic acid caused a second order type reduction of the microhardness, as well as structural changes in both dentin and enamel.
Mobility and percussion sound of healthy upper incisors and canines
Authors: Oikarinen K. , Kauppinen P. , Herrala E.
Published: April 2006

Abstract In order to evaluate the correlation between mobility and percussion sound, 126 upper incisors and canines in 21 student volunteers were measured by means of the Periotest (Siemens), by evaluating the percussion sound subjectively and by analyzing its spectrum. The attenuation time and frequency of the sound were measured for each tooth, A logical mobility and percussion sound existed in accordance with the sizes of the teeth. Spearman correlation coefficients close to 1.00 were noted in individual cases between the Periotest and the three other tests describing the percussion sounds.
Periodontal healing of replanted dog teeth stored in Viaspan, milk and Hank's balanced salt solution
Authors: Trope Martin , Friedman Shimon
Published: April 2006

Abstract This study examined, histologically, periodontal healing and root resorption of replanted dogs teeth stored in Viaspan for different time periods and compared these healing patterns to those after storage in milk or Hank's balanced salt solution (HBSS). Seventy‐two beagle incisors were endodontically treated, extracted, randomly divided and placed in Viaspan or milk for 6, 12, 24 and 36 h, and Viaspan or HBSS for 36, 48, 72 and 96 h, after which they were replanted. Four negative control teeth were immediately replanted while four positive controls were allowed to dry for one hour before replantation. All replanted teeth were splinted for 14 days. Two months after replantation the clogs were killed and the teeth histologically examined for healing of the supporting tissues. For Viaspan neither replacement nor inflammatory root resorption was seen after 6 and 12 h storage. A statistically significant rise in the incidence of replacement resorption was seen at 24, 36 and 48 h which decreased again at 72 and 96 h to levels equal to storage for 6 and 12 h. The occurrence of inflammatory root resorption was low and significantly increased only at 48 h after which it decreased significantly again. Viaspan proved superior to milk as a storage medium. Teeth stored in HBSS showed healing results similar to those stored in Viaspan.
A comparison of four root canal obturation methods employing gutta‐percha: a computerized analysis of the internal structure
Authors: Jacobsen E. L. , BeGole E. A.
Published: April 2006

Abstract The purpose of the present investigation was to compare the internal structure of gutta‐percha for presence/absence of empty spaces when used in four different obturation methods: thermoplastic, chloroform‐softened, thermomechanical, and warm lateral condensations. Each obturation was performed five times in a metal mold representing a root canal system. Following obturation the mold was disassembled and the gutta‐percha was freeze‐fractured at the 1.0, 3.5, and 6.5 mm levels as measured from the tip of the obturations. The fractured gutta‐percha was placed in a scanning electron microscope, the image transferred to a computer, and converted to digital data. The results were subjected to statistical evaluation. The results demonstrated no difference between the obturation methods at the 1 mm level, however at the 3.5 mm level, thermomechanical condensation produced an internal structure characterized by a greater number of empty spaces (p< 0.0007). At the 6.5 mm level, thermomechanical condensation differed only from the chloroform‐softened gutta‐percha (p<0.01).
In vitro solubility of human pulp tissue in calcium hydroxide and sodium hypochlorite
Authors: Andersen M. , Lund A. , Andreasen J. O. , Andreasen F. M.
Published: April 2006

Abstract The tissue solvent capacity of a 2% stabilized sodium hypochlorite solution (Milton®) and a commercial calcium hydroxide solution (Calasept®) was examined under in vitro conditions where autolyzed human pulp fragments weighing approximately 0.0065 g were immersed in these solutions at 37°C for periods of up to 10 days. It appeared that sodium hypochlorite was able to dissolve half the volume of pulp tissue within 1 h and the remaining tissue after 2–2 1/2 h. Calcium hydroxide dissolved half the pulp volume within 2 h, whereas it took 1 week for the remaining tissue to dissolve. These findings support the use of sodium hypochlorite as an irrigation solution during canal preparation and calcium hydroxide as a canal dressing for the purpose of creating a canal free of pulp remnants before root filling.
Rigidity of various fixation methods used as dental splints
Authors: Oikarinen K. , Andreasen J. O. , Andreasen F. M.
Published: April 2006

Abstract Horizontal and vertical rigidity of teeth fixed with seven types of denial splints were evaluated by two tooth mobility measuring devices. Altogether 21 dissected sheep mandibles including soft tissues were used for the experiments in which Fermit, flexible wire‐composite, Kevlar, Fiber, Protemp, rigid wire‐composite and Triad Gel splints were applied to four incisors. The mean rigidity of the central incisors within the splint was measured by means of Mühlemann periodontometer (horizontal mobility) and Periotest (horizontal and vertical mobilities). Mobility values of teeth before splinting were used as covariants and the values with the splints were illustrated as adjusted mobility. Statistical significance between the rigidity of various splints was analyzed by an unpaired t‐test. It was shown that the most rigid splints both in horizontal and vertical directions were Triad Gel, rigid wire‐composite and Fermit splints. Kevlar and Fiber splint allowed more horizontal movement than other splints. Protemp and flexible wire‐composite splints proved to produce adequate lateral support for the fixed teeth and allowed vertical flexibility which is experimentally known to improve periodontal healing of luxated teeth.
Resin restorations: leakage, bacteria, pulp
Authors: Qvist Vibeke
Published: April 2006

Abstract Through the development of composite resin materials, the acid‐etch technique and dentin adhesives, dentists can now complete perfect and permanent dental restorations – restorations with a color and shape approximating the natural tooth, with perfect marginal adaptation, and no harmful effects to the surrounding tissues, including the dental pulp. However, newer cross‐sectional studies indicate that marginal defects are still the main cause of replacement of resin restorations, and that their clinical durability is shorter than that of other types. Moreover, there is no doubt that gap preventive treatments can intensify pulpal reactions to resin restorations if bacterial leakage occurs. The present thesis is based on nine previously published studies (I‐IX), The aims of the studies were: to examine the possibilities of minimizing the occurrence of bacterial leakage around resin restorations through the use of various gap preventive procedures, to extend our understanding of their mode of action, and to investigate the pulpal reactions associated with restorations with and without bacterial leakage. The results of earlier research are reviewed, as well as the various methods for registration of gap occurrence around restorations. Studies I‐IX are described briefly and followed by a discussion of the results, a summary and some concluding remarks.
Efficacy of chlorhexidine in disinfecting dentinal tubules in vitro
Authors: Vahdaty A. , Ford T. R. Pitt , Wilson R. F.
Published: April 2006

Abstract Solutions of 0.2% and 2% chlorhexidine, 0.2% and 2% sodium hypochlorite (NaOCl) and normal saline were tested for their efficacy in disinfecting dentinal tubules following root canal irrigation in vitro. Freshly extracted bovine incisor roots were prepared as cylindrical shapes, 4 mm high and 5 mm wide with a lumen 2.1 mm wide. After mechanical removal of the cementum and elimination of the smear layer on the dentine surface with EDTA and NaOCl, the root sections were autoclaved and the dentinal tubules infected with E. faecalis (NCTC 775) by incubating in yeast extract glucose broth for 1 week. The root canals were irrigated with 20 ml of an irrigant solution using a syringe. Each irrigant was used in six specimens. Dentine was removed from the canal wall by sterile burs of increasing diameter to give samples 100, 100–300 and 300–500 μm deep. The dentine samples were then cultured to determine the presence and quantity of remaining micro‐organisms. The results indicated that chlorhexidine and NaOCl were equally effective antibacterial agents at similar concentrations against the test microorganism. They significantly reduced the bacterial counts in the first 100 μm of dentinal tubules, however up to 50% of dentine samples remained infected following use of both agents.
Occlusal interferences in association with teeth left in the line of mandibular fractures
Authors: Oikarinen Kyösti , Raustia A. M.
Published: April 2006

Abstract In order to evaluate whether teeth left in the line of mandibular fracture can predispose to occlusal interferences, the contact relationships between the maxillary and mandibular teeth in 37 mandibular corpus fracture patients were examined on the average 41 months after the injury. Control group consisted of 27 healthy dental students. It was shown that occlusal interferences were encountered in 38% (16/42) of teeth in the line of mandibular fracture in 38% (16/42) of their anterior and in 32% (9/28) of their posterior ones. Similar examination in the control group revealed interferences in 28% (113/400) so the ones found in teeth in the line of mandibular fractures can be supposed to have been caused by the injury and/or its treatment. It is also concluded that whether or not the interferences found in these patients were caused by the injury or its treatment or were signs of individual range they should be corrected with occlusal adjustment to prevent further pathological changes in these teeth and in the function of the masticatory system.
Internal resorption occurring after accidental extrusion of iodoform paste into the mandibular canal
Authors: Çallşkan Mehmet Kemal , Pişkin Beyser
Published: April 2006

Abstract The precise etiology of internal resorption is unknown but it is generally believed that triggering factors are infection and persistent chronic pulpitis. A case is presented with internal resorption, which developed subsequent to extrusion of iodoform paste from the adjacent tooth into the mandibular canal. According to clinical and radiographic examinations made after 7 years, the tooth was clinically asymptomatic, vital and the internal resorption was arrested without treatment.
Antibacterial activity of potential retrograde root filling materials
Authors: Chong B. S. , Owadally I. D. , Ford T. R. Pitt , Wilson R. F.
Published: April 2006

Abstract The antibacterial activity of potential retrograde root filling materials was assessed using the agar diffusion inhibitory test. A light‐cured glass ionomer cement (Vitrebond) and three reinforced zinc oxide‐eugenol cements (Kalzinol, IRM & ethoxybenzoic acid [EBA] cement) were compared with amalgam, a commonly used retrograde root filling material. Forty standardized pellets of each material were produced. Fresh, and materials aged for 1 week in sterile distilled water, were placed on blood agar plates inoculated with Streptococcus anginosus (milleri) or Enter ‐ococcus faecalis. At intervals of 3, 7 and 10 days, the presence and diameter of zones of inhibition were recorded. The diameter of the zones of inhibition increased with time for all materials, both fresh and aged. Vitrebond had the most pronounced antibacterial activity against both bacteria, producing the largest zone of inhibition, followed by Kalzinol. Amalgam had no measurable inhibitory effect whether aged or fresh, regardless of the period of exposure. There was no statistically significant difference in the response of the two bacteria. However, there were statistically significant differences between materials, period of exposure, and between fresh and aged materials (P < 0.001). Kalzinol, IRM and EBA cement were more antibacterial when aged than fresh, whilst Vitrebond was more active when fresh. Vitrebond was the only material for which the diameter of the zones of inhibition was reduced after ageing but it had the most pronounced antibacterial activity compared with the other materials. The antibacterial activity of the materials was ranked in the following order: Vitrebond > Kalzinol > (IRM = EBA cement) > amalgam.
Comparison of two calcium hydroxide pastes used for endodontic treatment of non‐vital immature incisor teeth
Authors: Mackie I. C. , Hill F. , Worthington H. V.
Published: April 2006

Abstract A proprietary calcium hydroxide paste, Reogan Rapid, that previously has been demonstrated to induce apical closure in non‐vital immature incisor teeth, was becoming unavailable. A prospective clinical trial was conducted to compare Reogan Rapid with another proprietary paste, Hypo‐cal. For teeth treated with Reogan Rapid apical closure was obtained in an average of 6.8 months involving 3.1 visits and the respective figures for teeth treated with Hypo‐cal were 5.1 months and 2.4 visits. These results demonstrated that Hypo‐cal was as effective as Reogan Rapid when used in a standardised technique for inducing apical closure.
Effect of fluoride on root resorption caused by mechanical injuries of the periodontal soft tissues in rats
Authors: Kameyama Y. , Nakane S. , Maeda H. , Saito T. , Konishi S. , Ito N.
Published: April 2006

Abstract The present study was carried out to investigate histologically and histometrically the effect of fluoride on root resorption induced by mechanical injuries of the periodontal soft tissues in rats. Resorption lacuna in the root surface of the molar in animals given both mechanical injuries and fluoride administration was significantly smaller in length and area than that in animals given only mechanical injuries. Moreover, resorption lacuna in the former animals contained fewer odontoclasts than that in the latter. The results of the present study might suggest that the administration of fluoride suppressed root resorption induced by mechanical injuries of the periodontal soft tissues.
Effectiveness of two different methods for preparing curved root canals
Authors: Zmener Osvaldo , Spielberg Carlos , Olmos Jorge
Published: April 2006

Abstract In this study, the effect of using two different methods for preparing curved root canals of extracted, single‐rooted teeth were analyzed with the scanning electron microscope. The instrumentation systems tested were the Canal Master and a standard circumferential filing technique in which conventional K‐files were used. Shaping effectiveness was qualitatively evaluated in terms of respect for conservation of the apical constriction and the presence or absence of ledging, specially in the apical third of the root canals. As a result of our observations, it appeared that the Canal Master instrumentation technique provided well‐centered and tapered preparations. Conversely, the use of conventional K‐files with a standard circumferential filing technique resulted in frequent alterations of the initial pattern of the root canals, showing transportation of the apical foramen and ledge formation.
In vitro evaluation of an audiometric device in locating the apical foramen of teeth
Authors: Felippe M. C. S. , Soares I. J.
Published: April 2006

Abstract A new audiometric device to determine the location of the apical foramen of teeth undergoing endodontic treatment according to “the relative value method” was tested in in vitro experiments. In 96.5% of the 350 human teeth used in the experiment, the location of the apical foramen was determined within acceptable limits (0–0.5 mm). In 60 teeth, where the measurements were based on an intermittent audio signal, a point about 1 mm short of the apical foramen was located. The results were considered promising and a clinical evaluation of the device will be carried out.
Reaction of inflamed periapical tissue to intracanal medicaments and root canal sealers
Authors: Tepel J. , el Sawaf M. Darwisch , Hoppe W.
Published: April 2006

Abstract The effects of different intracanal medicaments and zinc oxide‐eugenol based root canal sealers on an experimentally induced apical periodontitis were studied histologically in mesial roots of lower molars of Wistar rats. After root canal instrumentation each canal was filled either with an intracanal medicament twice for 3 days each time or with a sealer for 21 days. The intracanal medicament chlorophenol caused periapical tissue damage. P‐chloroxylenol‐camphor lead to periapical improvement as did 5% sodium‐hypochlorite. 12% sodium‐hypochlorite gave tissue damage. After intracanal medication with an aqueous suspension of calcium hydroxide periapical repair was clearly visible. A combination of a corticoid and an antibiotic appeared to induce damage of the periapical tissues. The root canal sealers Endomethasone and N2 essentially impaired periapical repair. The results were acceptable for Aptal‐Zink‐Harz root canal fillings after 21 days as well as after 56 days.
Replantation Of Avulsed Permanent Teeth With Avital Periodontal Ligaments: Case Report
Authors: Duggal M. S. , Toumba K. J. , Russell J. L. , Paterson S. A.
Published: April 2006

Abstract Five maxillary anterior teeth lost during a grand mal epileptic seizure, were replanted using the technique recently described by Andreasen (1) after an extra‐alveolar period of more than 72 h. The teeth were replanted surgically, 10 days after being avulsed, after they had been immersed in a 2.4% sodium fluoride solution and root filled with gutta‐percha. Ankylosis was evident 3 months post‐operatively. After 24 months there was evidence of considerable replacement resorption on the lateral incisors with little evidence of resorption on the other replanted teeth. Even though the long term prognosis is uncertain, this technique has an advantage of seeing the patient through the period of growth as well as maintaining the height of alveolar bone making possible the provision of an aesthetically acceptable prosthesis at a later age.
Histological observations of hard tissue barrier formation in amputated dental pulp capped with α‐tricalcium phosphate containing calcium hydroxide
Authors: Yoshiba K. , Yoshiba N. , Iwaku M.
Published: April 2006

Abstract This study was performed to evaluate the pulpal response to α‐tricalcium phosphate (αTCP) containing calcium hydroxide (Ca(OH)2). The dental pulps of monkeys were amputated and dressed with four agents: αTCP, αTCP containing 1% Ca(OH)2, αTCP containing 5% Ca(OH)2, and Ca(OH)2 being used as a control. The pulpal responses were histologically evaluated after 4 and 8 weeks. The pulp tissue treated with αTCP proliferated above the level of the original wound surface, and a thin layer of hard tissue barrier was formed directly against the capping agent. The barrier demonstrated atubular matrix lined with flattened or cuboidal cells, but occasionally appeared irregular in form. Ca(OH)2 dressing resulted in destruction of pulp tissue, with a thick hard tissue barrier being formed below the level of the exposure site. The barrier consisted coronally of osteodentin and pulpally of tubular dentin lined with odontoblast‐like cells. By contrast, 1% Ca(OH)2 added to αTCP produced a slight proliferation of pulp tissue. An atubular matrix barrier, pulpally lined with cuboidal cells, formed above the exposure site. It was later followed by the formation of tubular matrix lined with columnar cells. Teeth treated with 5% Ca(OH)2, showed a thin necrotic layer and a thick barrier formation. The barrier was composed of tubular dentin‐like tissue lined with odontoblast‐like cells. It would appear that αTCP containing a small amount of Ca(OH)2 may be clinically useful as a capping agent, as it induced consistent hard tissue formation, without excessive destruction of underlying pulp tissue.
Cytotoxicity of potential retrograde root‐filling materials
Authors: Chong B. S. , Owadally I. D. , Ford T. R. Pitt , Wilson R. F.
Published: April 2006

Abstract The Cytotoxicity of potential retrograde root‐filling materials was assessed using the Millipore filter method. A light‐cured glass ionomer cement, Vitrebond (VB), and three reinforced zinc oxide‐eugenol cements, Kalzinol, IRM and ethoxybenzoic acid (EBA) cement, were compared with amalgam. Twenty standardized pellets of each material, 10 fresh and 10 aged by storage in sterile distilled water for 72 h were produced. Ten filters were included as controls: five filters with a cell monolayer, but without test specimens, and another five without cells but with test specimens. Fresh IRM exhibited the most pronounced cytotoxic effect and the difference was statistically significant compared with all the other materials. There was no statistically significant difference between fresh VB, Kalzinol, EBA cement and amalgam. When aged, Kalzinol was the most cytotoxic and the difference was statistically significant compared with the other materials. Aged IRM was the second most cytotoxic material and this too was statistically different. The Cytotoxicity of VB, EBA, and amalgam did not differ significantly from one another.
Efficacy of XeCl‐308 excimer laser in fusing hydroxyapatite to seal the root apex
Authors: Mor C. , Stabholz A. , Neev J. , Rotstein I.
Published: April 2006

Abstract Sealing the root apex during apical surgery is important for a successful outcome. The effect of XeCl‐308 nm excimer laser irradiation on the fusion and seal of hydroxyapatite to the root apex was tested in extracted human teeth. Twenty‐four roots of intact single‐rooted premolars were instrumented to size 30 K‐file at the apex leaving a patent apical foramen. The apex of each tooth was covered with a freshly prepared paste of hydroxyapatite powder mixed with saline. The samples were then divided into two groups. In 12 teeth, the apical area was irridiated with XeCl‐308 nm excimer laser at a fluence of 0.7 J/cm2 for 5 s with pulse repetition rate of 25 Hz and a spot size of 0.13 cm2 immediately after the hydroxyapatite application. In the other 12 teeth, no laser treatment was performed after the hydroxyapatite application. The roots were mounted on a model for the detection of radicular leakage of hydrogen peroxide. The hydrogen peroxide leakage of each sample was measured and the difference between the test groups compared. The ability of the hydroxyapatite plug to prevent hydrogen peroxide leakage at the apex was also tested by applying compressed air from the triple syringe on the coronal access preparation for 2 min. Apical leakage was found in four teeth in the lased group and in eight teeth in the non‐plased group. However, the difference between the groups was not statistically significant.

Compressed air applied to the coronal access caused hydrogen peroxide leakage in all the teeth. Under the conditions of this study, the laser treatment did not seem to significantly improve the ability of the irradiated hydroxyapatite plug to seal the root apex.
A retrospective clinical and radiologic study of teeth re‐implanted following traumatic avulsion
Authors: Schatz J. P. , Hausherr C. , Joho J. P.
Published: April 2006

Abstract Re‐implantation is the recommended therapeutic procedure following traumatic exarticulation of teeth though its long‐term prognosis remains controversial. The purpose of the following study was to evaluate the periodontal healing of 33 reimplanted incisors lost after trauma. The sample, which included 24 upper and 9 lower incisors, was divided in two groups: 15 teeth were reimplanted within 1 hour (=Group A) and 21 teeth after 3 hours or more (=Group B). The reimplanted teeth were followed for different radiographic evaluation periods up to 5 years (mean = 2–9 years). The results showed a high rate of periodontal healing in Group A (66.7%), while Group B demonstrated a high percentage (83.3%) of both inflammatory and replacement resorption. Thus, even if the whole sample was prevented from drying before reimplantation, the teeth were affected by different rates of root resorption. Among the various prognostic factors suggested by the literature, bacterial contamination during extra‐alveolar storage seemed the most critical.
A new concept of education and knowledge retrieval through network systems
Authors: Schatz J. P. , Stouder A. , Joho J. P.
Published: April 2006

Abstract Recent epidemiological investigations reveal increasing figures of prevalence of dental traumatology: however, basic and clinical research is rather scarce in the scientific litterature. The development of computer technologies and the advent of communication pathways through network systems offer increased opportunities to disseminate theoretical and practical data on dento‐facial traumatisms. A new server launched on Internet, the global network system, is described and proposed to allow better recognition and information sharing through both practitioners and institutions in the field of dental traumatology.