bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bacterial Contamination Of Cracks In Symptomatic Vital Teeth
Authors: Kahler Bill , Moule Alex , Stenzel Deb 
Published: February 2010

AbstractAs part of an ongoing study on the initiation of cracks in teeth, 20 teeth exhibiting symptoms consistent with the presence of dentinal cracks were examined. The presence of a cracked cusp was confirmed by the selective application of pressure either with a mirror handle or Fracfinder (Svenoka, Dental Instruments, Vasby, Sweden). Cracked cusps were fractured from the teeth after the removal of all existing restorations and were immediately placed into ten percent formalin. Subsequently, specimens were dehydrated, sputter‐coated and examined under the scanning electron microscope (SEM). All the cracked cusps exhibited complete fracture of the dentine to the level of the dentino‐enamel junction. No partial fractures were seen. Numerous bacteria of many morphological forms were present on the dentinal surfaces, of all fractured cusps, in all teeth. Cocci, bacilli and filamentous forms were consistently found. Many bacteria were in the process of division. While bacterial contamination of dentinal cracks has been described in histological studies, the nature and distribution of these bacterial and fungal forms has not been shown previously in any detail. Prior SEM studies investigating the nature and mechanisms of fracture have not revealed bacterial contamination of the fractured surface. This paper draws attention to the fact that all symptomatic cracks in teeth appear to I. extend right through the dentine to the dentino‐enamel junction, and 2. appear to be extensively contaminated by bacteria.
Study Of Dentinal Tubule Architecture Of Permanent Upper Premolars: Evaluation By SEM
Authors: Ponce Elías Harrán , Sahli Carlos Canalda , Fernandez José Antonio Vilar 
Published: February 2010

AbstractDentinal tubules are the means by which the pulp and mineralised tissues surrounding the dentine (enamel and cementum) communicate. Through these tubules external agents can damage the pulp and subsequently the periodontal ligament. Given the importance of dentinal tubules, the authors evaluated the numerical density, shape, and individual surface area of tubule openings and the percentage of dentine occupied by these. Eight permanent upper premolars were studied using scanning electron microscopy (SEM).In the crown, the external surface of the dentine was evaluated at the dentino‐enamel junction and the internal surface at the pulp chamber wall. At the cervical, middle and apical thirds of the root, the external surface was evaluated at the cemento‐dentinal junction and the internal surface at the root canal wall.The results showed that numerical density of tubule openings is significantly greater (p < 0.05) at the cervical third of the dentine, at its junction with the cementum and at the pulpal chamber wall, with respect to other areas evaluated. The individual surface area of each opening varied from 5.72 μm2 in the dentine of the pulpal chamber wall to 0.97 μm2 in the dentine of the apical third of the root canal wall. The percentage of area occupied by the dentinal tubules per mm2 of dentine was significantly higher (p < 0.01) at the internal dentinal surface as compared to the external. The shape of the tubule openings was found to be circular in the crown and became more irregular as the apical third of the root was approached.
Anatomical Variation Of The Sphenomandibular Ligament
Authors: Garg Ankit , Townsend Grant 
Published: February 2010

ABSTRACTThe sphenomandibular ligament, which is derived from the sheath of Meckel's cartilage, is a fibrous structure that passes between the spine of the sphenoid bone and the lingula of the mandible. Although anatomical texts provide basic descriptions of this structure, there are few published reports of the extent of its variability or its possible clinical implications. The aim of this study was to provide a detailed description of the nature and extent of anatomical variability in the sphenomandibular ligament of seven human cadavers. Dissections of sagittally sectioned heads were performed using a medial approach that involved displacement of the tongue and mucosal tissues in the oral cavity and oropharynx, then reflection of the medial pterygoid muscle.The ligaments ranged in shape from thin bands that descended for a short distance from the spine of the sphenoid to broad bi‐concave ligaments with prominent insertions. The mylohyoid nerve was seen to pass behind the ligament in all specimens, emerging from the postero‐inferior border of the mandibular attachment before running into the mylohyoid groove on the medial surface of the ramus. Lying in the pterygomandibular space, the ligament was surrounded by fascia, both structures presenting potential barriers to the diffusion of local anaesthetic solution if injected medially. The appearance of the lingula also varied, and did not seem to reflect the size of attachment of the ligament, suggesting an alternative explanation of lingula morphology, perhaps related to a continuation of the mylohyoid ridge and anterior border of the mylohyoid groove.
Conservative Management Of An Intruded Immature Maxillary Permanent Central Incisor With Healing Complication Of Pulp Bone
Authors: Roberts Jemima , Olsen Christopher , Messer Harold 
Published: February 2010

ABSTRACTTraumatic intrusion injury of permanent teeth is serious with multiple complications possible associated with the pulp, periodontal ligament, alveolar bone and Hertwig's epithelial root sheath. The optimal treatment for the management of an intrusion injury has not yet been determined. A case is presented involving the conservative management of an immature maxillary permanent central incisor intrusively luxated by allowing for re‐eruption and orthodontic extrusion two weeks later. After a follow‐up period of ten months, the intruded tooth continued to show a mobility of grade one, without metallic percussion tone or infra‐occlusion, which confirmed periodontal ligament healing. Although the intruded tooth failed to respond to dry ice testing, no other signs of pulp necrosis were evident and the colour of the intruded tooth was within normal limits throughout the follow‐up period. However, complications of healing of Hertwig's epithelial root sheath occurred, causing in‐growth of bone and periodontal ligament into the root canal.
Advantages And Disadvantages Of New Torque‐Controlled Endodontic Motors And Low‐Torque NiTi Rotary Instrumentation
Authors: Gambarini Gianluca 
Published: February 2010

ABSTRACTThe main problem with the NiTi rotary instrumentation technique is instrument failure. During shaping procedures, rotary instruments might lock and/or screw into canals and, consequently, be subjected to high levels of stress. This may frequently lead to instrument separation or deformation. If a high‐torque motor is used, the applied forces are usually very high and the instrument‐fracture limit is often exceeded, thus increasing the risk of intracanal failure. A possible solution of this problem is to use a low‐torque endodontic motor, which operates below the maximum permissible torque limit of each and every rotary instrument. During clinical instrumentation of root canals, if a torque‐controlled motor is loaded right up to the instrument‐specific torque, the motor stops momentarily and/or starts rotating counter‐clockwise (auto‐reverse function) to disengage the locked instrument. These safety mechanisms were developed to reduce the risk of instrument fracture. The author fully discusses the rationale for selecting lower torque values in everyday endodontic practice, and provides clinicians with useful information on the advantages and disadvantages of new endodontic motors with torque control.
The Quality Of Clinical Fit Of Stainless Steel Bands Used In Endodontics
Authors: Pane E.S. , Messer Harold H. 
Published: February 2010

ABSTRACTStainless steel bands are commonly advocated to protect posterior teeth against fracture during endodontic treatment and before final restoration. A poorly fitting band, however, may lead to a compromised coronal seal and gingival irritation. This radiographic study assessed the quality of fit and marginal adaptation in the proximal area of stainless steel bands placed during routine endodontic treatment.Clinical radiographs of 120 maxillary and mandibular premolars and molars were evaluated. All radiographs were taken during routine clinical endodontic treatment and randomly selected from cases completed by ten operators. Approximately one‐half of cases did not meet the criteria of adequate marginal seal (mesial: 65/120; distal: 49/120). Only 11 teeth were found to have adequate fit of the band on both mesial and distal aspects of the tooth. The most common reason for inadequacy of fit was lack of band adaptation to the tooth contour in the cervical region. Stainless steel bands have a high possibility of poor marginal fit and should be used with the awareness that they may produce other clinical problems.
Pulpal Heat Changes With Newly Developed Resin Photopolymerisation Systems
Authors: Weerakoon A.T. , Meyers I.A. , Symons A.L. , Walsh L.J. 
Published: February 2010

AbstractComposite resin is a widely‐used direct tooth coloured restorative material. Photoactivation of the polymerisation reaction can be achieved by visible blue light from a range of light sources, including halogen lamps, metal halide lamps, plasma arc lamps, and Light Emitting Diode (LED) lights. Concerns have been raised that curing lights may induce a temperature rise that could be detrimental to the vitality of the dental pulp during the act of photoactivation. The present study examined heat changes associated with standardised class V restorations on the buccal surface of extracted premolar teeth, using a curing time of 40 seconds. The independent effects of type of light source, resin shade, and remaining tooth thickness were assessed using a matrix experimental design. When a conventional halogen lamp, a metal halide lamp and two different LED lights were compared, it was found that both LED lamps elicited minimal thermal changes at the level of the dental pulp, whereas the halogen lamp induced greater changes, and the metal halide lamp caused the greatest thermal insult of all the light sources. These thermal changes were influenced by resin shade, with different patterns for LED versus halogen or halide sources. Thermal stress reduced as the remaining thickness of tooth structure between the pulp and the cavity floor increased. From these results, it is concluded that LED lights produce the least thermal insult during photopolymerisation of composite resins.
Proliferative Activity In Periapical Lesions
Authors: Tripi Teresa Roberta , Bonaccorso Antonio , Rapisarda Ernesto , Bartoloni Giovanni 
Published: February 2010

ABSTRACTThe identification of proliferative activity in periapical lesions may be useful in discovering the biological behaviour of different cell types. Proliferant cell nuclear antigen (PCNA), Ki67, CD3 and p53 have been used for the evaluation of the proliferative ability of many lesions. In this study, 16 periapical granulomas and 8 radicular cysts were analysed. A semi‐quantitative method was used for evaluation of each lesion and antigen. According to the intensity of staining the following scores were assigned: 0 = no reactivity; 1 = reactivity above background; 2 = moderate reactivity; 3 = strong reactivity. Ki67 positive cells were present in all the periapical lesions. The antibody Ki67 was positive in pathological keratinic cells, while it was only slightly positive in normal epithelial cells. PCNA positive cells were present in 22 of the 24 cases examined. CD3 reactivity was also highly positive in periapical lesions. The reaction of oncoprotein p53 in periapical lesions was negative. The expression of the positive reaction of Ki67 and PCNA in periapical lesions is therefore an indicator of cell proliferation as a result of a chronic irritative stimulus.
The Use And Predictable Placement Of Mineral Trioxide Aggregate® In One‐Visit Apexification Cases
Authors: Steinig Torsten H. , Regan John D. , Gutmann James L. 
Published: February 2010

ABSTRACTEndodontic treatment of the pulpless tooth with an immature root apex poses a special challenge for the clinician. The main difficulty encountered is the lack of an apical stop against which to compact an interim dressing of calcium hydroxide (Ca(OH)2), or the final obturation material. In these situations the unpredictability of the result, the difficulty in creating a leak‐proof temporary restoration for the duration of treatment, and the difficulty in protecting the thin root from fracture may lead to complications when using traditional (Ca(OH)2‐based) apexiflcation techniques. Furthermore, given the increased mobility of today's society, lengthy treatment protocols are fraught with problems, and may not be followed through to completion. This may lead to ultimate failure of the case.Mineral Trioxide Aggregate (MTA®) has recently been introduced for use in endodontics. Current literature supports its efficacy in a multitude of procedures including apexiflcation. The focus of this paper is to propose a one‐visit apexiflcation protocol with MTA® as an alternative to the traditional treatment practices with Ca(OH)2. One‐visit apexiflcation may shorten the treatment time between the patient's first appointment and the final restoration. The importance of this approach lies in the expedient cleaning and shaping of the root canal system, followed by its apical seal with a material that favours regeneration. Furthermore, the potential for fractures of immature teeth with thin roots is reduced, as a bonded core can be placed immediately within the root canal.
MTA Apexification Combined With Conventional Root Canal Retreatment
Authors: Linsuwanont Pairoj 
Published: February 2010

ABSTRACTApexiflcation aims to induce apical closure of the open root apex with a hard‐tissue barrier, against which a root filling can be compacted. Despite the popularity of the apexification procedure, calcium hydroxide therapy has some disadvantages that include variability of treatment time, unpredictability of apical closure, difficulties with patient follow‐up and delayed treatment. Mineral trioxide aggregate (MTA) is a potential apical barrier material with good sealability and a high degree of biocompatibility. This paper demonstrates the placement of an apical barrier using MTA as an alternative to conventional long‐term calcium hydroxide therapy.
Torsional Properties Of New And Used Rotary K3 NiTi Files
Authors: Yared Ghassan , Kulkarni Gajanan K. , Ghossayn Fadia 
Published: February 2010

AbstractThe purpose of this study was to compare torque (gcm) and angle of rotation (degrees) at fracture of new and used NiTi K3 .04 rotary instruments. The relation between size of instrument and torque at fracture was also investigated. The torque and angle of rotation at fracture of new and used NiTi K3 .04 rotary instruments sizes 15 to 40 were determined according to ANSI/ADA Specification No. 28. Analysis of variance was used to compare the torque and angle of rotation at fracture among the different sizes of the new instruments and between new and used instruments of the same size (α = 0.05). The relationship between torque at fracture and size of instrument was determined with a regression analysis. Torque at fracture of the new instruments increased significantly with the diameter (p < 0.05). The used instruments, sizes 25 to 40, had significantly lower torque at fracture values compared to the new ones (p < 0.05). The used instruments, sizes 20 and 35 had significantly lower angle of rotation at fracture compared to the new ones (p < 0.05). A stronger relationship was found between the size of the file and the torque at fracture for the new instruments (p < 0.0001) compared to the used ones (p < 0.0001). The results of the present study suggested that the torque at fracture values of new instruments increased significantly with the diameter. The results also suggested that repeated use of .04 K3 instruments affected mainly the torque at fracture.
Carious Pulpitis: Microbiological And Histopathological Considerations
Authors: Martin F. Elizabeth 
Published: February 2010

AbstractDental caries is the result of microbial activities that induce the progressive localised destruction of teeth. Without treatment, this eventually results in infection of the dental pulp and surrounding periapical tissues. Although the bacteria responsible for caries initiation and early caries progression have been extensively studied, the microbiology of dentine caries reportedly shows considerable diversity and the associated microflora has not yet been fully identified. A search of the literature shows that few studies have analysed the microbiology of deep caries or examined the relationship between this microflora and the histopathology of chronic pulpitis in symptomatic teeth.The majority of the studies investigating the microbiology of carious dentine have used traditional culture methodology that has been reported to be fraught with difficulties and to underestimate the microbial populations. However, recent work using new technology in the form of Polymerase Chain Reaction (PCR) has shown potential by enhancing the identification and quantification of bacteria from complex environments. Application of this technology to carious dentine has identified an environment dominated by anaerobic organisms and containing significant numbers of Gram‐negative bacteria that have been strongly implicated in endodontic infections subsequent to carious pulpitis.Examination of the histopathology of pulp sections from teeth extracted as a result of carious pulpitis showed pulpal reactions ranging from minimal inflammation to marked inflammatory infiltration of the pulp tissue. Of interest, were hard and soft tissue pathologic changes noted in the pulp tissues resulting from the combined effects of the carious microorganisms and the host tissue response.Improved knowledge of the microbial species associated with pulpitis could create the potential for development of diagnostic tools and restorative materials with appropriate antimicrobial properties.
The Influence Of Smear Layer On Coronal Leakage Of Roth 801 And AH26 Root Canal Sealers
Authors: Khayat Akbar , Jahanbin Anahita 
Published: February 2010

The aim of this in vitro study was to examine the effect of removal of smear layer on the coronal seal of two commonly used root canal sealers: Roth 801, a zinc oxide‐eugenol‐based sealer and AH26, an epoxy resin‐based sealer. Ninety‐six single‐rooted human teeth were used. The teeth were instrumented and assigned to four experimental groups of 20 teeth each, with 10 teeth as controls and the remaining six teeth examined under a scanning electron microscope.The teeth in the experimental groups (80 teeth) were divided into four sub‐groups and were obturated by laterally condensed gutta‐percha with the two sealer cements as follows: Group A***l: smear layer left intact and AH26 cement used as sealer; Group A2: smear layer left intact and Roth 801 cement used as sealer; Group B***l: smear layer removed and AH26 cement used as sealer; and Group B2: smear layer removed and Roth 801 cement used as sealer.Coronal microleakage was evaluated by measuring the distance of dye penetration. The data was statistically evaluated using a two‐way ANOVA test.The results showed that removal of the smear layer resulted in a statistically significant reduction of microleakage values in the groups obturated with AH26 compared with the groups obturated with Roth 801 sealer. It was concluded that the removal of smear layer has a significant influence on the degree of microleakage in obturated root canals.
Histological Observations Of Periradicular Healing Following Root Canal Treatment
Authors: Khayat Akbar 
Published: February 2010

AbstractThe purpose of this study was to observe histologically the sequence of events leading to resolution of periradicular tissues, with a view to advancing the perception of periapical healing. Our material consisted of periapical specimens obtained from 15 single‐rooted, endodontically treated teeth of patients aged 25–40 years. All the teeth required extraction because of complicated crown‐root fracture following trauma, iatrogenic aetiology (cervical root resorption following bleaching) or extensive carious lesions. The patients were informed that, based on their clinical condition, surgical procedures should be performed under flap reflection in order to extract the fractured root. Informed consent, which was necessary for the surgery, was obtained in all cases. A small block section containing the apical root tip and surrounding periapical tissues was removed prior to root extraction. The results of histological examination revealed osteoblastic activty and osteoid bone formation six days after the root canal instrumentation. Periapical tissue healing was observed despite the presence of overfilled material. The lining epithelium was infiltrated with chronic inflammatory cells and surrounded by collagen bundles and newly formed bone.
Myofascial Pain And Toothaches
Authors: Kim Seung Tae 
Published: February 2010

AbstractDespite improved understanding of orofacial pain in recent years, accurate diagnosis of pain is still challenging in modern dentistry. Many disorders in the head and neck region are known to refer pain to dental structures and imitate dental pain. Due to the location of the perceived pain dental clinicians are often involved in the diagnosis and management of the pain. Myofascial pain (MFP) is widely believed to be the most frequently occurring orofacial pain of non‐odontogenic origin. It has long been known that MFP could mimic pulpitic symptoms. Past studies have shown that MFP is a relatively prevalent condition among the general population and the one that is most often misdiagnosed by dentists. Despite its prevalence and the potential for misdiagnosis, there has been little investigation into this old problem, and information about myofascial pain remains fragmented and poorly understood.In this article some of the features associated with myofascial pain will be highlighted. The interrelationship between myofascial pain and toothaches will also be examined and suggestions made in the areas of diagnosis and management of the condition. It is hoped that dental clinicians will be able to differentiate and manage the conditions effectively when dealing with them in the future.
Tissue Engineering In Endodontics
Authors: Nakashima Misako 
Published: February 2010

AbstractThe key elements of the regeneration of dentine‐pulp complex are stem cells, morphogens and a scaffold of extracellular matrix. The pulp stem cells have the potential to differentiate into odontoblasts in response to bone morphogenetic proteins (BMPs). However, the use of BMPs in vivo has been restrained by lack of a suitable scaffold. Therefore, two alternative approaches, in vivo and ex vivo gene therapy were performed. BmpII/GdfII gene was directly transferred into amputated pulp by sonoporation and the reparative dentine formation was stimulated in vivo. However, there should be enough responsive stem cells in the pulp. Therefore, the isolated progenitor stem cells from pulp were transfected with BmpII/GdfII by electroporation and implanted onto the amputated pulp. This ex vivo gene therapy stimulated reparative dentine formation more optimally and rapidly compared with the in vivo gene therapy. These results suggest the possible clinical use of gene therapy of BMPs for endodontics.