bluuebunny/crossref_metadata_2025 huggingface dataset:
Resin‐retained bridges in the treatment of traumatized dentition*
Authors: Creugers N. H. J.
Published: April 2006

Abstract Resin‐retained bridges can be used as the definitive treatment, as well as for interim treatment. Compared with conventional fixed prostheses, there are some advantages which make this treatment especially useful in traumatized dentition. The ultra conservative approach makes the adhesive bridge a standard treatment option in cases of uncertain prognostic factors. However, in such specific situations as traumatized dentition some complicating factors may be present. These complicating factors must be recognized and eliminated to create situations in which this kind of restoration can be succesful. Therapeutic and patient‐related factors are discussed using data from longitudinal clinical studies. Available clinical information indicates the anterior adhesive bridge to be a permanent restoration'. However, a benefit‐cost analysis is necessary to weigh the value of this restorations.
Some observations on the breakage of ultrasonic files driven piezoelectrically
Authors: Ahmad Majinah , Roy Ronald A.
Published: April 2006

Abstract The incidence of breakage of Piezon‐Master ultrasonic K files were evaluated. Three groups of unused files were subjected to three treatments, namely; free vibration in air without irrigation, free vibration in root canal while minimizing contact with the wall of canal in the presence of irrigation and light filing in root canal with free flow of irrigation. Cavitation produced by files in contact and free of contact with a glass surface was examined in order to observe the relationship between cavitation defects and breakage. In addition, the fractured and un‐fractured files were examined under a scanning electron microscope for the presence of cavitation pits. The results indicated that more files broke in air. In water, a higher incidence of breakage occurred when files were allowed to freely vibrate while no breakage occurred when the files were used in filing. All files generated cavitation which resulted in pitting of their surfaces. However, it was considered unlikely that the pits contributed to fracture. Fatigue cracks which could be the result of the manufacturing process were observed at some of the corners of the cross sections of the fractured files and could be the main contributory‐factor to fracture.
Moisture content of vital vs endodontically treated teeth
Authors: Papa J. , Cain C. , Messer H. H.
Published: April 2006

Abstract The moisture content of vital and endodontically treated teeth was compared in matched pairs of contralateral human teeth extracted for prosthodontic reasons. Samples from each tooth were weighed then placed in an oven to remove the unbound water from the dentin. Weighing was carried out daily until a constant weight was achieved for three days. The moisture content was then calculated and expressed as a percentage of the initial sample weight. It was found that vital dentin had a moisture content of 12.35% whilst dentin from endodontically treated teeth had a moisture content of 12.10%. These results indicated that there was no significant difference in the moisture content between endodontically treated teeth and vital teeth.
Inflammation and dental pain in man
Authors: Ahlquist M. L. , Franzen O. G.
Published: April 2006

Abstract In the present article special interest has been focused on indicators of latent and manifest pulpal inflammation studied by psychophysical and electrophysiological techniques. Intradental A‐delta nerve activity was recorded from two electrodes placed in the dentin on the labial tooth surface. The phychophysical measures were obtained by means of direct scaling methods in combination with sensory verbal descriptors. For stimulation cooling (ethyl chloride) and heating (hot guttapercha) of the tooth surface were employed. In addition, potentially algogenic substances, bradykinin and histamine, were administered on partly‐exposed pulps. Hot guttapercha induced a more complex neural response pattern than ethyl chloride. In all the recordings the responses evoked by heat showed a characteristic pattern consisting of three phases: an initial phase of short duration (i) followed by a depression in activity relative to the baseline (ii) and a slow spontaneously emerging activity in the absence of a physical stimulus (iii). The latter neutral event (iii) passed unnoticed by all the subjects. In the light of earlier experiments on feline pulp it was hypothesized that this third phase of the neural response was an indication of hyperexcitability in denial pulps and thus inflammation. Those subjects who experienced pulsating, dull, lingering pain (clinically diagnosed as pulpitis) showed a poor correlation between magnitude estimates of their mixed pain percepts and the total flux of A‐delta nerve activity. Bradykinin and histamine evoked dull pain in the majority of cases probably caused by excitation of pulpal C fibers. In one experiment A‐delta neural discharge of short duration could also be triggered by histamine. However, the pain sensation scaled by means of finger span significantly outlasted the neural response which may indicate a simultaneous activation of the A‐delta and C units. The dual response to histamine was interpreted as a sign of pulpal inflammation which may be a prerequisite for histamine to become an algogenic substance.
Dental trauma in children and adolescents in Valparaiso, Chile
Authors: Onetto J. E. , Flores M. T. , Garbarino M. L.
Published: April 2006

Abstract This study analyzed traumatic injuries in the primary and permanent dentition in children treated from 1990 to 1992 at the Children's Dental Traumatology Service in Valparaiso, Chile. A total of 227 records from patients 2 to 21 years old was studied with regard to the cause of injury, location of injury, time elapsed before treatment, history of previous trauma, type of injury, number of injured teeth., and how patients seek treatment. A total of 73 patients had injuries to the primary dentition (PD) and 154 to the permanent dentition (PD) with a total of 357 injured teeth (115 primary, 242 permanent). Ten to 12‐year‐old children had the highest number of injuries (33%). Falling was the most common cause of injury in both groups (82% pD, 58% PD), followed by striking against objects (13% pD, 19% PD) and bicycle accidents (9% PD). Most injuries in children with primary dentition (68%) occurred at home, while children with permanent dentition had most accidents at school (38%). Most children (61%) sought treatment after 24 h (52% pD, 65% PD), 61 children had suffered previous trauma (36% pD, 23% PD). The most common injuries in primary teeth were luxation (26%), intrusion (21%) and subluxation (18%). Uncomplicated crown fracture (34%), followed by complicated crown fracture (21%), were the main injuries in permanent teeth. There was no difference in the number of teeth involved for either dentition. A single tooth injury was found in 54%. Two teeth were involved in 35%, and three or more teeth in 11%. Tooth developmental disturbances were seen in 10 children with 14 permanent teeth involved, due to traumatic injuries that were unattended in the primary dentition.
Biological properties of IRM® with the addition of hydroxyapatite as a retrograde root filling material
Authors: Owadally I. D. , Chong B. S. , Pitt Ford T. R. , Wilson R. F.
Published: April 2006

Abstract The effect of adding 10% & 20% hydroxyapatite (HAP) on the antibacterial activity and cytotoxicity of IRM (Intermediate Restorative Material] when used as a retrograde root filling was compared with amalgam, a commonly used material. The antibacterial activity was assessed using the agar diffusion inhibitory test. Forty standardized pellets of each material were produced. Fresh materials, and materials aged for 1 week in sterile distilled water, were placed on blood agar plates inoculated with Streptococcus anginosus (milleri) or Enterococcus faecalis. The presence and diameter of zones of inhibition were recorded at intervals of 3, 7 and 10 days. There was no statistically significant overall difference in the response of the two bacteria tested. However, there were statistically significant overall differences in diameters of the zones of inhibition related to different materials, period of exposure and ageing of materials (P < 0.001). The diameter of the zones of inhibition increased with time for all materials, fresh and aged. IRM and both the HAP‐modified forms produced large zones of inhibition. Amalgam produced no measureable zones of inhibition whether aged or fresh, regardless of period of exposure and was different from the other materials (P < 0.001). The cytotoxicity was assessed using the Millipore filter method. Ten standardized pellets of each material were produced and aged by storage in sterile distilled water for 72 h. Ten filters were included as controls. Amalgam produced a consistent cytotoxic score of 1, and the difference between amalgam and the other materials was statistically significant (P < 0.001). Therefore, the antibacterial activity and cytotoxicity of the materials could be ranked in the following order: (IRM = IRM + 10% HAP = IRM + 20% HAP) > amalgam.
Coronal leakage as a cause of failure in root‐canal therapy: a review
Authors: Saunders W. P. , Saunders E. M.
Published: April 2006

Abstract This paper reviews the evidence that coronal leakage of root canals may lead to failure of root‐canal therapy. The causes of coronal leakage and methods by which this leakage may be prevented are described.
Splinting of avulsed central incisors with orthodontic wires: a case report
Authors: Dawoodbhoy I. , Valiathan A. , Lalanl Z. S. , Cariappa K. M.
Published: April 2006

Abstract A case of an 8‐year‐old boy who met with a road traffic accident causing trauma to the body and face and extrusion of the upper central incisors is reported. Laceration, oedema and limited mouth opening indicated the use of general anesthesia. During intubation the right central was avulsed accidentally and the left central further luxated and rotated. The avulsed central was reimplanted and the other one derotated and stabilised with orthodontic wire and brackets. Twelve weeks later the patients teeth were firm, immobile, radiographically normal and responded positively to vitality test.
A retrospective study of dento‐alveolar injuries
Authors: Schatz J. P. , Joho J. P.
Published: April 2006

Abstract Traumatic injuries to primary and permanent dentition may lead to severe therapeutic problems. The purpose of the investigation was to evaluate epidemiologic data of dentoalveolar injuries collected in a university dental clinic. The sample consisted of 300 patients (198 boys, 102 girls) representing 480 injured teeth, mostly maxillary incisors (94.6%). The results pointed‐out a high predominance of traumatized primary teeth. Types of injuries differed between deciduous and permanent dentition: luxation injuries were most often recorded in primary dentition (81%), while a high percentage of crown and crown‐root fractures were recorded in permanent dentition (38%). Epidemiological observations concerning location, etiology and distribution of dento‐alveolar injuries are briefly discussed.
Reliability of laser Doppler flowmetry in testing vitality of human teeth
Authors: Ingólfsson Æ. R. , Tronstad L. , Riva C. E.
Published: April 2006

Abstract The aim of this investigation was to study the reliability of the laser Doppler flowmetry (LDF) output signals when testing from 4 different positions on the buccal surface of human teeth. Recordings were made from 10 intact anterior teeth in 10 patients, mean age 27.4 years. Five types of probes were used. Each probe had 3 fibers arranged in a triangle, one lighted fiber and 2 receiving ones. The separation of the fibers was 1500, 1000. 800, 500 and 250 μm. The diameter of the fibers was 200 μm in all probes except the one with the smallest separation of fibers where it was 125 μm, A rubber base splint was used to position the probe on the buccal surface of the teeth tested. The first recording was made with the ingoing light in a gingival position. Then 3 additional recordings were made turning the probe 90° each time consequently changing the position of the ingoing light accordingly. Thus, gingival, mesial, incisal and distal recordings were obtained. The output signals were fed into a lap‐top computer upon which all calculations were done. The output signals from the incisalmost position of the teeth were significantly lower than the output signals from the other 3 positions with all probes except one. The turning of the probes into the 4 different positions affected the output signals from the probe with the smallest separation of fibers significantly more than the output signals from the other probes.
Incidence of dentoalveolar injuries in hospital emergency room patients
Authors: Luz J. G. C. , Di Mase F.
Published: April 2006

Abstract A retrospective survey over one year of a hospital emergency room population, seen at an oral and maxillofacial surgery clinic, found 271 patients (4.6% of the total population) with dentoalveolar injuries. A very large number of injuries occurred to children between the ages of 0 and 5 years (42.1%), and there was a significant number of injured patients in the adult population (19.1%). The ratio of male to female was 1.9:1. The leading cause of injury was falls (59.8%). The largest number of injuries was seen during summer. The diagnoses were lateral luxation (27.3%), concussion (17.3%), exarticulation (14.3%), tooth fracture (12.5%), intrusive luxation (11.1%), fracture of alveolar process (7.4%), extrusive luxation (3.7%), and cases with more than one diagnosis (6.3%). Most of the involved teeth were maxillary central incisors, in both dentitions.
Replantation of 400 avulsed permanent incisors. 2. Factors related to pulpal healing
Authors: Andreasen J. O. , Borum Mette Kit , Jacobsen Henrik Loft , Andreasen Frances M.
Published: April 2006

Abstract Four hundred avulsed and replanted permanent teeth were examined for pulpal healing. In 110 teeth, the apical foramen was either open or half‐open. In 16 teeth, the pulps were extirpated prophylactically. Thus, pulpal revascularization was considered possible in 94 teeth. Revascularization occurred in 32 teeth (34%). Pulp necrosis could usually be demonstrated after 3 weeks. Positive pulpal sensibility and radiographis signs of pulp canal obliteration were usually observed after 6 months. The effect of various clinical factors was examined, such as sex, age, type of tooth replanted, stage of root formation, type and length of extra‐alveolar storage, clinical contamination of the root surface, type of cleansing procedure of the root surface, type and length of splinting and the use of antibiotics. Finally, the width of the apical foramen and the length of the root canal were measured on radiographs taken at the time of injury. A multivariate statistical analysis revealed that pulpal revascularization was more frequent in teeth with shorter distances from the apical foramen to the pulp horns. Furthermore, that wet storage (saliva and/or saline) for more than 5 min decreased the chance of pulpal revascularization; whereas dry extraalveolar storage had a monotonous effect on pulpal revascularization, i. e. decreasing chance of revascularization with increasing length of the extraalveolar dry storage. Based on these findings, immediate replantation after brief cleansing in either tap water or saline is recommended.
Implications, prevention and management of subcutaneous emphysema during endodontic treatment
Authors: Battrum D. E. , Gutmann J. L.
Published: April 2006

Abstract Subcutaneous emphysema (SCE) is a possible complication of both nonsurgical and surgical endodontic treatment. A review of the literature pertinent to endodontic intervention and SCE is highlighted, while the causes of and recommendations for the prevention of SCE are provided. A review of the pathways whereby compressed air may travel through potential spaces in the head and neck is also illustrated in an attempt to identify the possibility of morbidity and even mortality' should operator induced SCE occur in a patient.
A complex treatment of dens invaginatus
Authors: Lindner C. , Messer H. H. , Tyas M. J.
Published: April 2006

Abstract Dens invaginatus is a developmental malformation of teeth. A case is presented of successful treatment of a peg lateral incisor with a severe dens invaginatus extending to the root apex. Both conventional endodontic therapy and periapical surgery were ineffective in resolving a persistent, long‐standing sinus tract. Removal of the tooth in the present case would have created a difficult prosthetic problem. Intentional replantation, with improved access to the apical part of the canal was attempted as a last resort. A 10‐month recall radiograph is presented showing successful healing of the periapical lesion. Pre‐treatment and post‐treatment photographs are presented to show successful esthetic treatment, using bonded composite resin.
Effect of root canal filling materials containing calcium hydroxide on the alkalinity of root dentin
Authors: Staehle H. J. , Spiess V. , Heinecke A. , Müller H.‐P.
Published: April 2006

Abstract The effect of root canal filling pastes containing calcium oxide resp. calcium hydroxide on the alkalinity of extracted human teeth was investigated using a colour indicator (cresol red). An aqueous suspension of calcium hydroxide (Pulpdent), which is normally used for temporary root canal filling, most consistently produced alkalinity. Removal of the smear layer following instrumentation of the root canal led to increased proportion of alkaline‐positive spots in dentinal locations distant from the canal. A clearly smaller effect was found with a calcium salicylate cement (Sealapex) and an oil‐paste (Gangraena Merz), both of which are available for definite root canal fillings. Following removal of the smear layer, these hard‐setting preparations caused moderate alkalinity in dentin adjacent to the canal but no effect was observed in locations more distant from the canal. Neither at locations adjacent to nor distant from the root canal was alkalinity found when another calcium salicylate cement (Apexit) was used. Apparently the release of hydroxyl ions into root dentin from calcium hydroxide containing root canal filling materials is not solely influenced by the absolute amount of calcium hydroxide, but also depends on other ingredients which variably inhibit the release of these ions.
Adhesion of a glass ionomer cement to human radicular dentine
Authors: Weiger R. , Heuchert T. , Hahn R. , Löst C.
Published: April 2006

Abstract The adhesion of cements to root canal surfaces is a crucial factor for strengthening non‐vital teeth ‐ weakened due to extensive loss of tooth structure ‐ by cemented posts. The aim of this study was to determine the tensile strength of a glass ionomer cement (Ketac‐Cem) on root canal walls following pretreatment with conditioners. Upon cleaning and shaping, 56 straight root canals ‐ divided into seven groups ‐ were conditioned with one of the following solutions: NaOCl (1%) + EDTA (20%), H3PO4 (37%), HNO3 (2.5%), citric acid (6%), polyacrylic acid (10% and 20%) and NaCl (0.9%) as control. Standardized dentine cylinders were prepared out of the coronal half of each root perpendicular to the root axis and subsequently split. The exposed root canal areas were coated with Ketac‐Cem. Using an universal testing machine a tensile force was applied to Ketac‐Cem up to fracture. Pretreatment with EDTA‐NaOCl provided the strongest bond strength (2.2 MPa). The median values for the other conditioning solutions ranged from 1.2 to 1.9 MPa. The significantly weakest bond (0.5 MPa) was recorded for NaCl. The elimination of the smear layer appeared to be an essential factor in order to improve the adhesion.
Nd: YAG laser irradiation in root canal disinfection
Authors: Moshonov J. , Ørstavik D. , Yamauchi S. , Pettiette M. , Trope M.
Published: April 2006

Abstract The purpose of this study was to assess the efficacy of Nd:YAG laser irradiation in disinfecting the root canal system. Seventy‐five teeth were uniformly instrumented and sterilized, and their root canals were infected for 60 min with an overnight culture of Enterococcus faecalis in Tryptic Soy Broth. The teeth were divided into 6 groups: 1 ‐ non‐infected controls; 2 ‐ infected controls; 3 ‐ infected, laser treated; 4 ‐ infected, laser dummy (dye only); 5 ‐ infected, laser dummy (dye and air‐water spray); 6 ‐ infected, NaOCl‐treated (reference group). After treatment, the root canals were dried and dentinal shavings removed for a post‐treatment culture. Quantitative analysis of bacteria surviving the various treatments were performed, and the bacterial counts for each group were compared. SEM analysis of teeth split longitudinally was used to illustrate the effect of treatment on the smear layer and on surface bacteria. Nd:YAG laser irradiation (group 3) significantly reduced the number of bacteria while NaOCl irrigation (group 6) effectively disinfected the canals.
Endodontic pathogens: propagation of infection through patent dentinal tubules in traumatized monkey teeth
Authors: Ehnevid H. , Jansson L. , Lindskog S. , Weintraub A. , Blomlöf L.
Published: April 2006

Abstract Periapical pathology indicating endodontic infection, when present in marginal periodontitis‐affected teeth, has recently been shown to be an aggravating factor in progression of marginal destruction. This has been associated with patency of dentinal tubules in the tooth cervix, an area normally devoid of cementum following periodontal therapy. These studies are, however hampered by that only circumstantial evidence such as presence of periapical destruction have been applied as criteria of endodontic infection. The purpose of the present investigation was to study to what extent a predefined selection of endodontic pathogens inoculated in the root canal can influence periodontal pathology and healing in areas of the root covered by or devoid of cementum, using root resorption as a histomorphometric marker. Exposed dentine surfaces, in the present study showed significantly larger areas of resorption in infected roots compared to non‐infected roots, while cementum surfaces showed an almost identical distribution of tissue reactions regardless of root canal infection or not. It was concluded that endodontic pathogens or their products were not able to penetrate the cementum barrier. The significantly larger areas of resorption on exposed dentine surfaces in infected roots compared to non‐infected roots indicated that endodontic pathogens or their products could spread through dentinal tubules to a root surface void of cementum. Extrapolated to the marginal situation this indicated that endodontic pathogens in the root canal might be able to aggravate marginal infection in areas of the root devoid of cementum.
In vitro evaluation of the cytotoxicity of calcium hydroxide‐based root canal sealers
Authors: Beltes P. , Koulaouzidou E. , Kotoula V. , Kortsaris A. H.
Published: April 2006

Abstract The cytotoxicity of three calcium hydroxide‐containing root canal sealers (Sealapex, CRCS and Apexit) was tested by using L929 and BHK 21/CIS cells. After setting for 24h, the sealers were covered with cell suspension. Cytotoxicity was determined by a quantitative technique at 24h, 48h and 72h. All the sealers were found to be cytotoxic. Sealapex showed the highest cytotoxicity, causing a significant decrease in cell density. CRCS was less toxic than Sealapex and more toxic than Apexit. Apexit proved to be the least toxic material.
Sealing ability of potential retrograde root filling materials
Authors: Chong B. S. , Ford T. R. Pitt , Watson T. F. , Wilson R. F.
Published: April 2006

Abstract The sealing ability of two potential retrograde root filling materials, a light‐cured glass ionomer cement (Vitrebond) and a reinforced zinc oxide‐eugenol cement (Kalzinol) was compared with that of amalgam using three methods of assessment: bacterial leakage, confocal microscopy and Indian ink leakage. The root canals of 80 extracted human single‐rooted teeth were prepared. All the teeth were apicected, retrograde cavities were prepared and then divided into four equal groups of 20 teeth. The teeth were sterilised by autoclaving and the retrograde cavities filled with the test materials. In the control group, retrograde cavities in 10 teeth were left unfilled while cavities in another 10 teeth were sealed with cyanoacrylate cement. The teeth were first subjected to a bacterial leakage test using Enteroccocus faecalis as a leakage marker. After which, the adaptation of the retrograde root fillings was assessed using a confocal optical microscope. Finally, the teeth were processed for the Indian ink leakage test. Bacterial leakage occurred in more teeth filled with amalgam compared with both Vitrebond and Kalzinol (P < 0.001), between which there were no differences. With confocal microscopy, the size of the marginal gap was largest with amalgam and smallest with Vitrebond; all differences were statistically significant (P < 0.001). Finally, there was more Indian ink penetration with amalgam compared with both Vitrebond and Kalzinol (P < 0.001) but there were no differences between Vitrebond and Kalzinol. Although there were individual differences within samples, overall, the three methods of assessment produced similar results. The sealing ability of Vitrebond and Kalzinol was similar and both materials were better than amalgam.
Effects of mandibular nerve block on heat‐ or cold‐induced changes in pulpal blood flow in man
Authors: Mavropoulos A. , Endal U. , Aars H. , Brodin P.
Published: April 2006

Abstract – Laser Doppler flowmetry (LDF) was used to study the effect of mandibular nerve block, using 3% mepivacain, on heat‐or cold‐induced changes in pulpal blood flow (PBF) evoked by application of cold or heat to the lingual surfaces of teeth 33 and 43 in nine young subjects. PBF on average showed a 7% increase in response to heat (48°C) and a 20% decrease when exposed to cold (3°C). Neither response was affected by mandibular block. From this we concluded that the effects on PBF of the presently applied heating and cooling of the tooth were solely due to direct thermal influences on the blood vessels, without involvement of vasomotor or sensory nerves.
Traumatic crown fractures in permanent incisors with immature roots: a follow‐up study
Authors: Cavalleri G. , Zerman N.
Published: April 2006

Abstract – A follow‐up study of crown fractured permanent incisors with incomplete root formation was carried out in a group of patients, aged 6–12 years, over a 5‐year‐period in the Dental Clinic of the University of Verona, Italy. The number of injured patients was 55, representing 84 injured incisors. All patients were followed clinically and radiographically using a standardized follow‐up protocol. The most common type of trauma was fracture of enamel and dentine without pulpal exposure (80%) and the most common type of treatment was restoration with the acid‐etch composite resin technique (46%). Bonding of the crown fragment was performed in 10 instances (12%). At the 5‐year‐control all teeth with fracture of the enamel had no pulp complications. Four of 67 teeth (6%) with fracture of the enamel and dentine without pulpal involvement showed pulp necrosis and 1 tooth showed pulp obliteration (1.5%). Eight of 14 teeth (57%) with fractures of the enamel and dentine with pulp involvement showed pulp necrosis. Aesthetically 36 of the restored teeth were deemed satisfactory (43%). In 9 teeth the bonded fragment had to be rebonded. 14 teeth were considered unsatisfactorily restored due to wear of the composite (17%). 34 restored teeth had to be retreated because of a new trauma (40%). In one tooth a previous bonded fragment had to be rebonded. These results confirmed that crown fractures without pulp involvement in permanent incisors with incomplete root formation have a low percentage of pulp complications, while 60% of the teeth with crown fractures with pulp involvement had pulp complications.
Mandibular canine with two roots and three root canals
Authors: Heling I. , Gottlieb‐Dadon I. , Chandler N. P.
Published: April 2006

Abstract – A rare case of root canal retreatment in a lower canine with two roots and three canals is presented. While the presence of two roots and two canals in one root is not uncommon, the finding of three canals in a lower canine appears not to have been reported previously.
Treatment of large periapical lesions by inserting a drainage tube into the root canal
Authors: Tsurumachi Tamotsu , Saito Tsuyoshi
Published: April 2006

Abstract Long‐term drainage and depressurization is performed by inserting a stainless steel tube into the root canal of teeth with persisting periapical exudation. This article presents 2 cases of large periapical lesions showing a complete healing of bone after the drainage tube procedure. The tube allows lasting drainage, relieves the pressure and modifies the local apical environment so the host defense mechanism can exert repair process.
Dental pulp response to traumatic injuries – a retrospective analysis with case reports
Authors: Feiglin B.
Published: April 2006

Abstract The reactions of the denial pulp to traumatic injuries can be extremely varied. They range from almost immediate pulp death to long‐term slow pulp canal calcification. In this study the pulpal reactions were divided into three types: pulps with a very poor prognosis that required endodontic therapy soon alter the tooth was traumatized. Seventy‐nine teeth were studied in this category, and all 79 teeth required endodontic therapy; pulps with a moderate prognosis that required endodontic intervention some 18 to 24 months after the traumatic episode. Forty‐eight teeth were studied in this category, and 27 of them required endodontic therapy: pulps with a very good prognosis that rarely required endodontic therapy. Fifty‐two teeth were studied in this category, and only 2 required endodontic therapy. The prognosis of a particular pulp depends on the degree and type of trauma.
The reliability of electrical pulp test after concussion injury
Authors: Pileggi R. , Dumsha T. C. , Myslinksi N. R.
Published: April 2006

Abstract Traumatic injuries lo teeth present a difficult diagnostic problem with respect to determining the vitality of the effected teeth. Conventionally, a latency period of I lo (i weeks is proposed as die amount of lime required for the return of a positive electric pulp lest (EPT) response; however, this has been based on empirical data. The purpose of this study was to 1 determine a time frame during which a return of a reliable response to EPT may be measured, and 2) correlate this time frame with pulpal vascular changes dial occur after traumatic injuries. Four canines from each of nine ferrets were used for this experiment (18 traumatized and 18 control teeth. A reproducible concussion injury was devised by releasing a known weight at a constant height above the facial surface of the experimental teeth. The KPT response was confirmed by the use of an EMG muscle recorder. Animals were killed at 24, 48 and 72 h and 6, 12 and 28 days alter the injury and the teeth analyzed histologically. The histological sections showed an absence flammatory cells in both groups; however, according to the N1H image system, an increase in the number of vessels was detected in die experimental group when compared to die controls. In a majority of the cases, a positive response to the EPT returned within 12 days post concussion injury and as early as 10 days. In addition, a significant vascular change was accompanied with the loss of die EPT response. This study provided a reliable method by which concussion injuries may be studied using an animal model.
Influence of storage conditions of extracted teeth on dentine removal by a standardised method of filing
Authors: May Cheng J.‐A. Lam , Gulabivala K.
Published: April 2006

Abstract Extracted teeth are often stored in a variety of solutions for different lengths of time prior to use in studies on the efficacy of root canal preparation. The aim of this study was to evaluate the effect of duration (12 h, 1, 4 and 15 weeks) and type of storage medium (Saline, Formal‐saline, Sodium Hypochlorite and Dry conditions) on dentine removal by standardised filing. Apparatus was constructed to standardised variables inherent in filing. These included the file, the rate, duration and amplitude of its push‐pull motion, its alignment with a flat dentine surface, die interfacial force (80 gms) and rate of irrigation. Freshly extracted teeth were immediately stored in one of the 13 combinations of storage media and duration. The teeth were prepared into test specimens by splitting the roots and flattening the root canal surface. Twenty specimens were designated to each combination. Dentine removal was quantified by profilometry using maximum depth at 8 selected points. Statistical analysis of the mean values showed highly significant differences (p<0.001) between the media at 1 4 and 15 weeks. When comparisons of mean values were made within the storage groups, there were highly significant differences (p<0.001) in dentine removal between 0, 1, 4 and 15 weeks of storage in sodium hypochlorite and saline. There were no significant differences found for storage in formal‐saline. In dry conditions, the differences were significant (p<0.001) between 0, 1, 4 and 15 weeks of storage, but were not significant when the 4 weeks values were excluded.
Cutting characteristics of a sonic root‐end preparation instrument
Authors: Devall R. , Lumley P. J. , Waplington M. , Blunt L.
Published: April 2006

Abstract The aim of this study was to investigate the culling ability of retro tips powered by a sonic handpiece (MM 1500, Micro Mega, Prodonta, Geneva, Switzerland). Two levels of the following variables were evaluated in this study: a) power selling with the air inlet ring half or fully open, b) orientation of lip perpendicular or parallel to the long axis of the handpiece, c) length of tip 2 or 3 mm, d) loading of 25 or 50 grams, e) tip size 35 or 55. The substrate used was 1 mm thick set lions of bovine bone and load was controlled by using a load cell interfaced with a transducer meter. Instrumentation time was fixed at 10 seconds with water irrigation. A 25 full factorial analysis was performed with two replications making a total of 64 experimental units. The resultant depth of cm was measured using a stereo microscope at x50 magnification. Analysis of the data indicated that all variables had a significant effect on cutting (ANOVA p<0.05). The most significant factor was power, followed by tip length, tip orientation, width and load. An increase in loading resulted in tip constraint and a reduction of culling at the lower power selling. In conclusion sonic ally activated retro tips were found to cut satisfactorily with instrument air inlet ring opening/power having the main effect.
Prognosis of root‐fractured permanent incisors
Authors: Çalişkan M. K. , Pehlivan Y.
Published: April 2006

Abstract The prognosis of 56 root‐fractured permanent incisors was evaluated clinically and radiographically for 2 to 31 years. Information about initial case histories, examination and treatment of root‐fractured teeth were recorded retrospectively from patient cards. Most of the‐root fractures occurred in the 16–20 year age group (38%) followed by the 11–15 year age group (29%). Males were involved more often than females. Fifty‐two percent of the patients visited the dental clinic with in the first week, while 48% did so 1 month‐31 years later alter the injury. The leading cause of root fractured injuries was falls (46%) and mostly involved one tooth (71%). Maxillary central incisors were the most often affected teeth (95%). The most common type of root fracture was in the middle third of the root (57%) followed by apical part (34%). About 59% of untreated or splinted teeth maintained their vitality. Healing with connective tissue was observed in 19 teeth, with calcified tissue in 15 teeth and with osseous tissue in only one tooth. There was partial or complete obliteration of the pulp space in these healed cases (62.5%). The formation of pulpal hard tissue produced no additional clinical problems. Partial or total pulp necrosis were noted in 21 (37.5%) teeth. Endodontic treatment was successful in 12 cases. The remaining 9 teeth were extracted due to the loss of marginal alveolar bone and apical periodontitis.
Management of dens evaginatus: evaluation of two prophylactic treatment methods
Authors: Sim T. P. C.
Published: April 2006

Abstract Dens evaginatus (DE) is an odontogenic anomaly characterized by an enamel covered tubercle, enclosing dentin and pulpal tissue. It most commonly aliens premolar teeth of people of mongoloid ethnicity. The prevalence of DE in Singapore is 2.1%. Fracture or attrition of the tubercle may lead to pulpal necrosis. Thus, prophylactic management of DE is preferred. A retrospective cohort study comparing two common prophylactic restorative methods was conducted. This involved 817 children, aged 10 years at the outset, having 1591 DE. The teeth were observed for 2 years. The results showed that significantly less teeth developed pulpal pathology when an enamoplasty‐preventive resin restoration method was used (0.52%) as compared to an amalgam cavity restoration (5.37%) and the control (3.65%) [x2= 9.595 (p<0.01) df = 2]. Knowledge of the various treatment options and prevalence data is important as there is an increasing global migration of people of mongoloid ethnicity.
Polylactic acid (PLA) root replica in ridge maintenance after loss of a vertically fractured incisor
Authors: Suhonen J. T. , Meyer B. J. A.
Published: April 2006

Abstract A periodontally affected tooth was prepared for a special treatment: Calcium hydroxide was introduced into the apical half of the root canal whereas its cervical part was filled with glass ionomer cement. The tooth was shortened subgingivally. After 6 weeks of epithelization over the residual root a palatal full‐thickness flap was mobilized. The root was carefully extracted and chairside copy‐milled from the biodegradable polylactic acid (PLA) material. The PLA‐replica was implanted immediately into the socket and the flap was sutured. Aim of the treatment was to prevent the ridge collapse of the extraction area. Ridge height could be preserved during the 21 months of observation. With time the radiographic density of the cancellous bone increased in the implanted area, indicating that a PLA‐replica is replaced by host's bone tissue.
Endodontic treatment of teeth with apical periodontitis using calcium hydroide: a long‐term study
Authors: Çahşkan M. K. , Şen B. H.
Published: April 2006

Abstract The aim of this study was to evaluate clinically and radiographically the long‐term results of endodontic therapy. A total of 172 mature teeth with periapical radiolucencies with and without symptoms were treated endoclontically using calcium hydroxide paste as the intracanal medicament and a calcium hydroxide containing root canal sealer. In 58 teeth, the dressing‐was accidentally or intentionally extruded into the lesions. All cases were followed up for a period of 2–5 years. The teeth in which the dressing was extruded did not show a different healing pattern from the ones treated conventionally. The complete healing rate for all cases was 80.8% while incomplete healing had taken place in 7.6% of the cases.
Push‐out strength and SEM evaluation of resin composite bonded to internal cervical dentin
Authors: Patierno J. M. , Rueggeberg F. A. , Anderson R. W. , Weller R. N. , Pashley D. H.
Published: April 2006

Abstract The bond strength of a resin composite used with a dual‐cured dentin bonding system to internal cervical bovine dentin was evaluated using a direct or indirect placement technique. Teeth were sectioned transversely to produce 4 mm‐thick specimens. The root canals were enlarged to a standardized taper, treated with a dentin bonding system, and filled with a lightcured resin composite using either direct, incremental composite placement or indirect composite placement of a pre‐polymerized composite inlay. The debond stress of indirectly placed restorations using a composite inlay was 8.5 (SD±2.7) MPa which was significantly greater (p<0.0001) than the value of 5.0 (SD±1.9) MPa for composite placed in a conventional, incremental manner. SEM evaluation revealed the indirect placement technique demonstrated increased resin tag density and length as compared to the direct technique. Enhanced retention of resin composite to endodoutically prepared dentin treated with a dentin bonding system was obtained by using a composite inlay technique as opposed to direct, incremental buildup of the material.
Experimental apexigenesis in baboons
Authors: Das S. , Das A. K. , Murphy R. A.
Published: April 2006

Abstract Apexification with calcium hydroxide is a routine procedure. However, some clinical reports suggest that root completion can occur by controlling the infection without use of a catalyst. The present study investigated the use of tetracycline treatment (in root canals) on root growth in immature teeth, rendered non‐vital experimentally. Incisors in 3 young baboons were exposed and canals were left open. After 2 months all canals were cleaned and treated with either tetracycline or formocresol. Some canals in each group were filed. Animals were sacrificed after 6 months. Bacterial evaluations were done before placing medications, one week later and six months after that. The number of bacteria were reduced in all treatment groups. Root growth almost near completion was observed in more teeth treated with tetracycline than in the formocresol group.
Comparative in vitro investigation of different methods for temporary root canal filling with aqueous suspensions of calcium hydroxide
Authors: Staehie H. J. , Thomä C. , Müller H.‐P.
Published: April 2006

Abstract Three methods for temporarily filling root canals with calcium hydroxide pastes were compared. Each of 20 root canals of extracted, human, single‐rooted teeth was shaped with hand instruments under standardized conditions up to ISO size 50 and filled using a syringe system, a lentulo spiral or an endodontic reamer. Quality of fillings was assessed radiographically and by inspecting ground preparations. Ridit (relative to an identified distribution) analysis was employed to confirm differences in frequencies of certain quality criteria obtained with various application methods. With regard to degree of obturation and occurrence of porosities, application of temporary fillings with a lentulo spiral or syringe system revealed significantly better results than application with hand instruments (reamer). No differences with regard to degree of obturation were detected when comparing results obtained with syringe or lentulo. Fewer porosities in the apical part of the root canal were seen, both on radiographs and ground sections, with the syringe system compared with the lentulo spiral. In the presence of some contradictory reports found in the literature, the present study suggests that, after straight or slightly curved root canals have been shaped up to at least ISO size 50, high quality temporary root canal fillings may be obtained by application of an aqueous suspension of calcium hydroxide with a syringe system.
Periodontal healing of extracted dogs’ teeth air‐dried for extended periods and soaked in various media
Authors: Pettiette M. , Hupp J. , Mesaros S. , Trope M.
Published: April 2006

Abstract The aim of this study was to determine the periodontal healing of replanted dogs’ teeth which, after extended extra‐oral dry times, had been soaked in various media before replantation. Incisors and premolars of beagle dogs were root canal treated, extracted and bench dried. The teeth were grouped according to dry times of 30, 45 and 60 minutes. Each group of teeth was soaked in one of three media, Hank's balanced salt solution, Via Span (Belzer UW‐CSS, Dupont Pharmaceuticals), or Conditioned Medium (supernatant of confluent culture of human gingival fibroblasts) for 30 minutes before replantation. Controls consisted of teeth extracted and replanted without drying or soaking (negative control), and bench‐dried teeth replanted without soaking in the media (positive control). The dogs were killed 6 months after replantation of the teeth, which were prepared for histologic evaluation. Five um cross‐sections (every 70 Jim) of the root and surrounding tissue were evaluated for healing/resorption according to Andreasen's criteria. The best healing occurred for the roots which had been immediately replanted. Healing in the positive control groups decreased with increased dry time. For the 30–minute dry time groups, soaking in media had no beneficial effect on periodontal healing compared with the controls. Soaking in ViaSpan resulted in an increased healing incidence for both the 45‐ and 60‐ minute bench‐dried groups while soaking in the other media had no consistent beneficial effect. It appears from this study that an avulsed tooth that has been left dry for 30 minutes should be replanted immediately without soaking. However, teeth that have been dry for 45 or 60 minutes would benefit from soaking for 30 minutes in ViaSpan.
Tooth discoloration by blood: anin vitrohistochemical study
Authors: Marin P. D. , Bartold P. M. , Heithersay G. S.
Published: April 2006

AbstractAnin vitromodel, using a modification of a technique devised by Freccia & Peters, was developed to investigate tooth staining following pulpal haemorrhage. Samples of whole blood, erythrocytes, plasma and platelet concentrate and saline were individually placed in the pulp chambers of groups of five teeth and centrifuged twice daily for 25 min over a period of 3 consecutive days. This confirmed that the blood pigment responsible for the staining was found only in those samples containing erythrocytes. Teeth stained with packed red cells were then prepared for histological examination and subjected to four histochemical tests: (1) benzidine, (2) zinc leuco, (3) Perl's and (4) Turnbull Blue to analyse some of the biochemical changes following haemorrhage into the pulp chamber. These tests showed that, following haemolysis of erythrocytes within dentine, haemoglobin was found either intact or as one of the haematin molecules with no further breakdown of the haem structure and no evidence of any free ferric ions or haemosiderin.
Computerized 3‐D reconstruction of two “double teeth”
Authors: Lyroudia K. , Mikrogeorgis G. , Nikopoulos N. , Samakovitis G. , Molyvdas I. , Pitas I.
Published: April 2006

Abstract “Double teeth” is a root malformation in the dentition and the purpose of this study was to reconstruct three‐dimensionally the external and internal morphology of two “double teeth”. The first set of “double teeth” was formed by the conjunction of a mandibular molar and a premolar, and the second by a conjunction of a maxillary molar and a supernumerary tooth. The process of 3‐D reconstruction included serial cross‐sectioning, photographs of the sections, digitization of the photographs, extraction of the boundaries of interest for each section, surface representation using triangulation and, finally, surface rendering using photorealistic effects. The resulting three‐dimensional representations of the two teeth helped us visualize their external and internal anatomy. The results showed: a) in the first case, fusion of the radical and coronal dentin, as well as fusion of the pulp chambers; and b) in the second case, fusion only of the radical dentin and the pulp chambers.