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At least 739 records · Page 41Linked to original sources
PubMed2005

Anatomic analysis of the Genial Bone Advancement Trephine System's effectiveness at capturing the genial tubercle and its muscular attachments.

OBJECTIVE: The Genial Bone Advancement Trephine (GBAT) System (Stryker Leibinger Inc, Kalamazoo, MI) is a 1-step system that advances the genial tubercle for treatment of retrolingual obstruction in obstructive sleep apnea. The purpose of this project was to anatomically analyze the effectiveness of the GBAT System to capture the genial tubercle and its muscular attachments in the circular trephine. METHODS: Eight cadaveric heads (ages 54-89 years; 3 female and 5 male) were examined, and Panorex radiographs (Stryker Leibinger Inc, Kalamazoo, MI) were obtained. Seven specimens were selected on the basis of mandibular height and dentition to undergo the procedure. The procedure was performed using the GBAT system with the 14-mm trephine according to the stepwise instructions. The mandibles were dissected, and analysis of the location of the osteotomy with respect to the genial tubercle, genioglossus muscles, geniohyoid muscles, and mandibular dentition was performed. RESULTS: All 7 of the specimens had complete capture of the genial tubercle. The mean percentage of the genioglossus muscle captured in the circular trephine was 85% (50%-100%). All specimens had preservation of the posterior muscle fibers. The mean percentage of the geniohyoid muscle captured was 78% (15%-100%). No tooth roots were transected or contained in the bone plug. CONCLUSIONS: The GBAT System is an effective 1-step system for capturing and advancing the genial tubercle and its muscular attachments in the treatment of OSA.

Aged↗
PubMed2005

Abutment load transfer by removable partial denture obturator frameworks in different acquired maxillary defects.

STATEMENT OF PROBLEM: Excessive stress on abutment teeth adjacent to a maxillary resection defect during loading of partial denture obturator frameworks may shorten the life of the teeth. PURPOSE: The aim of this study was to photoelastically compare the forces exerted on the supporting structures of abutment teeth in 3 differently sized surgical resections with removable partial denture designs used to restore such maxillectomy defects. MATERIAL AND METHODS: Composite photoelastic models were constructed of a human maxilla that had undergone each of 3 maxillectomies: partial, radical, and radical involving the contralateral premaxilla. The abutment teeth included all remaining anterior teeth, the first premolar, and second molar, except the radical maxillectomy, which included the contralateral premaxilla where all remaining teeth were used as abutment teeth. All abutment teeth were restored with complete metal crowns, and removable partial denture frameworks were fabricated. Loading zones were selected according to the resection, and a 10-lb load was applied at each load point. The resulting stresses were observed and recorded photographically in a circular polariscope. The 2 teeth adjacent to the resection were then splinted, and the loading regimens were repeated. RESULTS: Without splinting, loads closer to the defect produced lingual tipping of the teeth adjacent to the resection and a mesial tipping tendency of the second molar. The tipping effects were greatest in the model with the largest resection. Splinting reduced tipping of the teeth adjacent to the resection and produced more uniform stress around these 2 abutment tooth roots for all of the models. CONCLUSION: The results of this in vitro study suggest that splinting the 2 teeth adjacent to a resection defect improves stress distribution around the roots during loading. This could increase the clinical life of the abutment teeth.

Birefringence↗
PubMed1998

NADPH-diaphorase activity in nerves and Schwann cells in the periodontal ligament of rat incisor teeth.

The lingual portion of the incisor periodontal ligament demonstrated activity for nicotinamide adenosine dinucleotide phosphate (NADPH)-diaphorase. Schwann cells surrounding Ruffini-like endings coexpressed NADPH-diaphorase activity and immunoreactivity for inducible nitric oxide synthase. NADPH-diaphorase-positive nerve fibres which coexpressed immunoreactivity for neuronal nitric oxide synthase were in contact with Schwann cells surrounding Ruffini-like endings or terminated as free nerve endings. Neural NADPH-diaphorase activity could not be found in the tissues covering the labial portion of incisor tooth root. It is possible that nitric oxide in Schwann cells and nerves has functions specific to the incisor periodontal ligament.

Animals↗
PubMed2000

The effects of local trauma to the enamel-related periodontal tissues in the eruption of the rat incisor.

The periodontal tissues related to enamel (PTE) of the rat incisor comprise a connective tissue derived from the dental follicle and the enamel organ with its successive stages of development. Localized damage to these tissues in rat lower incisors was done surgically in three ways: with an endodontic file introduced into the labial periodontal space through either (i) its basal or (ii) its incisal extremities, or (iii) by the partial removal of the mandibular lower border, at the level of the molar teeth, together with the introduction of an endodontic file into the incisal part of that space. The lesions in the molar region of the PTE produced first a variable period of retarded eruption, and, depending upon their extent or degree were followed by a cessation of the eruptive movement and, in the majority of the operated teeth, a recovery of the normal eruption rate before the end of the experiment (17 weeks after surgery). Access to the PTE through the basal portion of the socket was erratic, but when the tissues were damaged produced similar effects. Effects on eruption of lesions produced through the alveolar crest were minimal or even absent. Localized injury to the periodontal ligament of either lower or upper incisors did not produce similar effects on tooth eruption. The dental follicle and the enamel organ of teeth of limited growth when their crown is completed are similar to the PTE in the molar region of continuously growing rodent incisors. In teeth of limited growth these tissues play an essential part in the intraosseous stage of eruption. The results here suggest that the PTE may also have a role in the supraosseous stage of eruption, which is continuous in teeth such as rat incisors due to the presence of a continuously functioning odontogenic organ.

Alveolar Process↗
PubMed2002

Quasi-linear viscoelastic behavior of the human periodontal ligament.

Previous studies have not produced a comprehensive mathematical description of the nonlinear viscoelastic stress-strain behavior of the periodontal ligament (PDL). In the present study, the quasi-linear viscoelastic (QLV) model was applied to mechanical tests of the human PDL. Transverse sections of cadaveric premolars were subjected to relaxation tests and loading to failure perpendicular to the plane of section. Distinct and repeatable toe and linear regions of stress-strain behavior were observed. The amount of strain associated with the toe region differed as a function of anatomical location along the tooth root. Stress relaxation behavior was comparable for different anatomical locations. Model predicted peak tissue stresses for cyclic loading were within 11% of experimental values, demonstrating that the QLV approach provided an improved, accurate quantification of PDL mechanical response. The success of the QLV approach supports its usefulness in future efforts of experimental characterization of PDL mechanical behavior.

Aged↗
PubMed2006

[Sequelae of dental trauma: forensic medical aspects].

Dental trauma is a frequent condition which may occur alone or in combination with craniofacial trauma and/or other injuries. Many factors influence the gravity of the trauma and subsequent prognosis including age, anterior state, trauma etiology, treatment and follow up. In order to establish a prudent provisional or definitive expertise, the medical expert must have a panoramic view of the trauma. Time should be taken to consolidate facts and estimate prejudices on sound evidence. In certain cases outcome can be predicted. The medical expert should provide advice and counselling both for the patient and the mandating authority. In this article, iatrogenic dental accidents occurring during anesthesia or extraction will not be discussed.

Adult↗
PubMed1994

Bacteria invading periapical cementum.

The aim of this study was to determine whether microorganisms invade periapical cementum of human teeth from the adjacent periapical lesions. We therefore attempted to isolate microorganisms from periapical cementum through the adoption of standard anaerobic procedures for obligate anaerobes. Samples of cementum were taken from 10 amputated tooth roots at the time of apicoectomy. From two of these samples, bacteria were recovered after anaerobic incubation, but no bacteria were recovered after aerobic incubation of the same samples. Of a total of eight isolates from the cementum, seven were obligate anaerobes and one was aerotolerant. The obligate anaerobes isolated were assigned to the genera Prevotella, Peptostreptococcus, Eubacterium, and Fusobacterium. The aerotolerant anaerobe was Campylobacter. From this, we conclude that bacteria can successfully invade cementum via periapical periodontal tissue, and that such bacteria may play a significant role in chronic periapical pathosis.

Actinomyces↗
PubMed1991

A new model system for measuring intracanal temperatures.

A new model system was developed which allows intracanal temperature measurements to be recorded during repeated obturations of a human tooth root canal. A human central incisor was embedded in clear orthodontic resin and sectioned longitudinally. Sixteen thermocouples were secured at 2-mm intervals along two surfaces of the root canal. The thermocouples were connected to a computerized temperature recording system to measure intracanal temperatures produced by high-temperature thermoplasticized injectable gutta-percha. The system was capable of recording 16 simultaneous temperatures every second with an accuracy of a hundredth degree centigrade. There was a linear increase in the recorded temperatures in the root canal. However, the actual temperatures were lower than expected.

Body Temperature↗
PubMed2004

Quasi-automatic 3D finite element model generation for individual single-rooted teeth and periodontal ligament.

The paper demonstrates how to generate an individual 3D volume model of a human single-rooted tooth using an automatic workflow. It can be implemented into finite element simulation. In several computational steps, computed tomography data of patients are used to obtain the global coordinates of the tooth's surface. First, the large number of geometric data is processed with several self-developed algorithms for a significant reduction. The most important task is to keep geometrical information of the real tooth. The second main part includes the creation of the volume model for tooth and periodontal ligament (PDL). This is realized with a continuous free form surface of the tooth based on the remaining points. Generating such irregular objects for numerical use in biomechanical research normally requires enormous manual effort and time. The finite element mesh of the tooth, consisting of hexahedral elements, is composed of different materials: dentin, PDL and surrounding alveolar bone. It is capable of simulating tooth movement in a finite element analysis and may give valuable information for a clinical approach without the restrictions of tetrahedral elements. The mesh generator of FE software ANSYS executed the mesh process for hexahedral elements successfully.

Algorithms↗
PubMed1998

Emergency treatment of orodental injuries: a review.

There has been an increase in the incidence of injuries to the incisor teeth in the primary and permanent dentitions over the last decade; one study reported that roughly 35% of 9-year-old children will have damaged their teeth in some way. Much has been written about dental injuries, and there may be confusion about the appropriate emergency treatment for different types. Classification and understanding of the types of injury are essential before diagnosis and treatment can be undertaken. Although dental injuries can occur singly, they more usually involve a combination of injuries to a tooth and its supporting structures. Prompt, accurate diagnosis and appropriate emergency treatment as outlined in this paper will greatly improve the prognosis for many dentoalveolar injuries. The aim must be to ensure that the third of the population of preteenage children who damage their teeth are not resigned to loss of an incisor in later life because of inaccurate diagnosis and poor treatment of the emergency condition.

Child↗
PubMed1978

Combined surgical and orthodontic management of the oral abnormalities in children with cleidocranial dysplasia.

Children with cleidocranial dysplasia have dental abnormalities which combine to prevent normal tooth eruption, and which if untreated may result in abnormal facial and jaw growth. A technique combining orthodontics and oral surgery has resulted in the establishment of excellent occlusion and facial appearance in these patients. Recent advances in direct enamel bonding techniques for orthondontic attachments have permitted a conservative surgical approach with minimal bone removal during surgery to expose unerupted teeth prior to orthodontic treatment.

Adolescent↗
PubMed1980

Experimental transplantation of mature molar teeth with and without the supporting structures in mice.

Two types of dental isografts were implanted into the femoral bone of inbred mice: type A, encompassing mature maxillary molars including supporting structure and type B, consisting of the tooth alone. The isografts, together with their host tissues, were examined histologically beginning at day 1 and continuing until day 42 posttransplantation. In both types, the cellular components underwent necrosis with subsequent repopulation of the pulp and periodontal ligament of the graft. A new bony socket formed and partial resorption and ankylosis started on day 10 of transplantation. It is suggested that the host cells present in the periodontal ligament are responsible for the ankylosis and resorption of the tooth root surface.

Animals↗
PubMed1998

A novel pyrroleninone cross-link from bovine dentine.

The aim was to identify suspect collagen cross-links in dentine, eluting close to known cross-links in ion-exchange HPLC. Bovine tooth roots as source of dentine were powdered, demineralised, reduced, and acid-hydrolysed. Cross-linking amino acids were isolated from the acid hydrolysate by size exclusion, adsorption, and sequential ion exchange chromatography. In addition to dihydroxylysinonorleucine and hydroxylysylpyridinoline, an unknown cross-link was isolated (V-2). The ultraviolet, mass, and nuclear magnetic resonance spectra support the proposed structure of V-2, a trimeric amino acid with a pyrroleninone nucleus.

Amino Acids↗
PubMed1992

The effects of infraocclusion: Part 3. Dental arch length and the midline.

The third and final article in this series examines the effect of infraocclusion on the midline of the mandibular dental arch. From clinical observation, a shift in the dental midline to the side affected by infraocclusion seemed very common, and this could be explained within the terms of the hypothesis proposed in the first article. A method was devised on a panoramic radiograph to define and to distinguish the anatomic (skeletal) midline and the dental midline. This confirmed the existence of a dental shift to the affected side. The hemiarch length of each side was measured on the film, from the distal of the second deciduous molar/second premolar to both constructed midlines, and was found to be longer on the affected side, confirming an abnormally distal position of the first molar on that side.

Ankylosis↗
PubMed1997

Three-dimensional effects in retraction appliance design.

The clinical importance of the three-dimensional effects of the force systems supplied by appliance designs used for retraction has long been appreciated. However, quantification of these force systems is not as well known. In this work, a numerical method is used to provide quantitative insight into three-dimensional effects for typical appliance designs. One problem that occurs clinically is the axial rotation of a single rooted tooth as a result of the forces being applied by the retraction device on the tooth's buccal surface. An out-of-plane preactivated bend can be used to counteract this rotation. The proposed numerical method can accurately determine the force systems resulting from this out-of-plane preactivation as well as the in-plane force systems. It is shown that the out-of-plane effects are independent of the in-plane behaviour so that the usual forces and moment to force ratios are maintained.

Elasticity↗
PubMed1998

Posttreatment assessment of surgically exposed and orthodontically aligned impacted maxillary canines.

The records of 96 consecutively treated patients, with a total of 110 exposed maxillary canines, were reviewed after orthodontic alignment of the exposed teeth. In view of the high degree of clinical and patient satisfaction with the results, a random sample of 25 patients, with a total of 30 exposed canines, were critically assessed. The assessment involved scoring for clinical impression, mobility, gingival condition and pocketing, oral hygiene, vitality, and radiographic appearances. The results indicate that the technique of surgical exposure and orthodontic alignment of ectopic maxillary canines provides a satisfactory method of treatment.

Adolescent↗
PubMed1999

Radiographic localization of unerupted maxillary anterior teeth using the vertical tube shift technique: the history and application of the method with some case reports.

The preferred means of radiographic localization is the parallax method introduced by Clark in 1910. He used 2 periapical radiographs and shifted the tube in the horizontal plane. In 1952, Richards appreciated that a vertical tube shift could also be carried out. No major changes then occurred in the technique until Keur, in Australia, in 1986 replaced the periapical radiographs with occlusal radiographs. This modification enables a greater tube movement and therefore a greater shift of the image of the impacted tooth; it also ensures that the whole of the tooth is captured on the radiograph. For the vertical tube shift, Keur introduced the use of a rotational panoramic radiograph with an occlusal radiograph. In 1987, Southall and Gravely discussed this vertical tube shift combination in the English dental literature, and it is now the preferred combination of radiographs for localizing impacted maxillary anterior teeth. Jacobs introduced this method to the American literature in 1999, but it has yet to gain acceptance in the continental European literature. Jacobs recommended, when using this combination, to routinely increase the vertical angulation for the occlusal radiograph by 10 degrees to achieve a greater image shift. Four case reports are presented in this article. Three have photographs taken at surgical exposure to illustrate how the position of the impacted tooth can be accurately predicted by appropriate interpretation of the radiographs.

Adolescent↗