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Biting Force (biting + force)
Selected AbstractsPeriapical biomechanics and the role of cyclic biting force in apical retrograde fluid movementINTERNATIONAL ENDODONTIC JOURNAL, Issue 9 2005A. Kishen Abstract Aim, To investigate the stress distribution pattern in the periapical region caused by biting forces and to study the role of cyclic biting loads on periapical fluid movement. Methodology, In the first part, a digital photoelastic experiment was conducted to study stress distribution in the periapical region. In the second, 20 maxillary central incisors were selected and divided into three main groups: normal intact teeth (group 1), tooth specimens in which the root canal was enlarged and maintained wet (group 2), and tooth specimens in which the root canal was enlarged and maintained dry (group 3). The tooth specimens were placed in a polycarbonate support with a cavity filled with a sponge soaked in methylene blue solution to simulate a periapical defect with exudate. During testing, the specimens were placed in a water bath at 37 °C, and were loaded cyclically with a load of 20 N, at a rate of 72 cycles min,1, to a maximum of 20 000 cycles. The specimens were then sectioned and evaluated for retrograde fluid movement using light microscopy. The data were analysed using one-way anova (post hoc tests). Results, Digital photoelastic experiments showed that the compression of teeth produced bending stresses in the periapical region. Testing with cyclic loads demonstrated retrograde fluid movement into the apical portion of the root canal and extraradicular region in all groups. There was a significant difference amongst the apical retrograde fluid movement displayed by different groups (<0.01). Group 2, in which the root canal was enlarged and maintained wet showed maximum retrograde fluid movement, whilst group 3, in which the root canal was enlarged and maintained dry showed the least retrograde fluid movement. Conclusions, Biting forces would cause bending of the periapical bone and cyclic biting forces would contribute to retrograde fluid movement into the root canal space and extraradicular region. [source] Calibration of T-Scan® sensors for recording bite forces in denture patientsJOURNAL OF ORAL REHABILITATION, Issue 9 2009G. S. THROCKMORTON Summary, Although measurement of maximum voluntary biting force is an important indicator of health of the masticatory system, few commercially available transducers have been validated for routine clinical use. The T-Scan III® system records distribution of relative forces around the tooth row during clenching, but not absolute forces. This study assesses the reliability of T-Scan® sensors with and without protection materials and develops calibration curves that allow measurement of absolute forces with the T-Scan III®. [source] An in vitro assessment of the strength of porcelain veneers dependent on tooth preparationJOURNAL OF ORAL REHABILITATION, Issue 12 2000P. Hahn The treatment of teeth using veneer restorations combines aesthetic and functional improvements with a low destructive technique. Different kinds of tooth preparation techniques are described in the literature for this kind of restoration. This in vitro study aimed to examine the influence of the incisal preparation on the loadability of teeth restored with porcelain laminate veneers. Thirty-six selected mandibular incisors were randomly assigned to three groups with 12 teeth per group. In the first group, only the facial surface was prepared. In the second group, the preparation included a rounded incisal edge and a distinct chamfer lingually. The third group served as an unprepared control. Empress® veneers were then fabricated and cemented with a low viscous luting composite material. After 120 days storage in Ringer's solution, the specimens were loaded incisally to the point of failure. Statistical analysis of the results showed significant differences between the series (P=0·0103). Group 2 (with preparation of the incisal edge) exhibited the lowest fracture resistance (466±99 N) (N, mean forces). When prepared only facially, the teeth restored with Empress® veneers reached the strength of unprepared teeth. Compared with the biting force described for incisors in the literature, the in vitro loadability reached in this investigation seems to jusitify the clinical use of both preparation designs tested. [source] Using a Motion-Capture System to Record Dynamic Articulation for Application in CAD/CAM SoftwareJOURNAL OF PROSTHODONTICS, Issue 8 2009Oliver Röhrle PhD Abstract Purpose: One of the current limitations of computer software programs for the virtual articulation of the opposing teeth is the static nature of the intercuspal position. Currently, software programs cannot identify eccentric occlusal contacts during masticatory cyclic movements of the mandible. Materials and Methods: Chewing trajectories with six degrees of freedom (DOF) were recorded and imposed on a computer model of one subject's maxillary and mandibular teeth. The computer model was generated from a set of high-resolution ,-CT images. To obtain natural chewing trajectories with six DOF, an optoelectronic motion-capturing system (VICON MX) was used. For this purpose, a special mandibular motion-tracking appliance was developed for this subject. Results: Mandibular movements while chewing elastic and plastic food samples were recorded and reproduced with the computer model. Examples of mandibular movements at intraoral points are presented for elastic and plastic food samples. The potential of such a kinematic computer model to analyze the dynamic nature of an occlusion was demonstrated by investigating the interaction of the second molars and the direction of the biting force during a chewing cycle. Conclusions: The article described a methodology that measured mandibular movements during mastication for one subject. This produced kinematic input to 3D computer modeling for the production of a virtual dynamic articulation that is suitable for incorporation into dental CAD/CAM software. [source] Periapical biomechanics and the role of cyclic biting force in apical retrograde fluid movementINTERNATIONAL ENDODONTIC JOURNAL, Issue 9 2005A. Kishen Abstract Aim, To investigate the stress distribution pattern in the periapical region caused by biting forces and to study the role of cyclic biting loads on periapical fluid movement. Methodology, In the first part, a digital photoelastic experiment was conducted to study stress distribution in the periapical region. In the second, 20 maxillary central incisors were selected and divided into three main groups: normal intact teeth (group 1), tooth specimens in which the root canal was enlarged and maintained wet (group 2), and tooth specimens in which the root canal was enlarged and maintained dry (group 3). The tooth specimens were placed in a polycarbonate support with a cavity filled with a sponge soaked in methylene blue solution to simulate a periapical defect with exudate. During testing, the specimens were placed in a water bath at 37 °C, and were loaded cyclically with a load of 20 N, at a rate of 72 cycles min,1, to a maximum of 20 000 cycles. The specimens were then sectioned and evaluated for retrograde fluid movement using light microscopy. The data were analysed using one-way anova (post hoc tests). Results, Digital photoelastic experiments showed that the compression of teeth produced bending stresses in the periapical region. Testing with cyclic loads demonstrated retrograde fluid movement into the apical portion of the root canal and extraradicular region in all groups. There was a significant difference amongst the apical retrograde fluid movement displayed by different groups (<0.01). Group 2, in which the root canal was enlarged and maintained wet showed maximum retrograde fluid movement, whilst group 3, in which the root canal was enlarged and maintained dry showed the least retrograde fluid movement. Conclusions, Biting forces would cause bending of the periapical bone and cyclic biting forces would contribute to retrograde fluid movement into the root canal space and extraradicular region. [source] An Overview of Complete Artificial Fixed Dentition Supported by Endosseous ImplantsARTIFICIAL ORGANS, Issue 1 2005Dennis Flanagan Abstract:, The construction of a complete restoration of the dentition by the surgical placement of endosseous titanium implants that support a fixed prosthesis in each jaw is possible. The positionings of the implants and teeth in the prostheses are important factors for a successful long-term result. Distribution of the occlusal biting forces over as many implants as possible is important. Off-axial occlusal biting forces should be diverted to the anterior jaws where the forces are not as great. The posterior teeth should be designed with flat occlusal surfaces that separate during excursionary mandibular chewing movements. Medial mandibular flexure caused by the contraction of the medial pterygoid muscle can be addressed by constructing the prosthesis in segments, so as not to have a rigid entity encased in flexing bone that may induce stress in the bone, potentially leading to loss of implant integration and failure. Segmenting also ensures an appropriate fit of the prosthesis with respect to casting and porcelain firing distortion. Lip support by means of a flange in the prosthesis may be necessary when there has been a large amount of bone loss from edentulous resorption. Cleaning and routine maintenance of the prostheses every 3,6 months is essential. [source] | ||||||||||