Supporting Bone Structure Research Articles

The prevalence of headshaking in horses with primary and secondary dental sinusitis and computed tomographic evidence of infraorbital canal pathology.

Sinusitis is a common disease of horses yet there are a limited number of reports in the literature that describe the prevalence of infraorbital canal (IOC) pathology and headshaking behaviour in horses diagnosed specifically with primary sinusitis and secondary dental sinusitis. Given the impact that these behaviours can have on horses' intended athletic use, investigation is warranted. To determine the occurrence of IOC pathology in horses with concurrent primary or secondary dental sinusitis based on computed tomography (CT) findings and to assess whether the frequency of headshaking behaviour is influenced by the presence of IOC pathology. Retrospective case series. Computed tomography studies were assessed for sinusitis (unilateral or bilateral), IOC pathology (unilateral or bilateral) and description of IOC disease including displacement, deformation, periosteal proliferation, hyperostosis, osteolysis and infraorbital nerve exposure. Behaviour outcome was determined by client questionnaire five or more years following CT scan. A total 65 out of 66 horses diagnosed with primary or secondary dental sinusitis demonstrated IOC changes on CT. Hyperostosis (86%), periosteal proliferation (85%) and osteolysis (86%) were common CT findings. Hyperostosis was frequently found to involve both the IOC and supporting bone structure. Five cases were euthanized immediately after CT acquisition or during hospitalisation following diagnostic investigations. Follow-up was obtained in 48/61 cases, with five horses showing headshaking behaviour. Infraorbital nerve histopathology was not performed. The limited number of cases with no IOC pathology prevented direct comparison between sinusitis groups both with IOC pathology and without IOC changes. The client questionnaire carries a memory bias. Computed tomography changes involving the IOC may not predict headshaking behaviours in sinusitis secondary to dental disease. This finding is important in the context that these behaviours render some horses unusable and unsafe for their intended riding discipline.

The Impact of Chronic Kidney Disease on Nutritional Status and Its Possible Relation with Oral Diseases.

Several studies have demonstrated a strong relation between periodontal diseases and chronic kidney disease (CKD). The main mechanisms at the base of this link are malnutrition, vitamin dysregulation, especially of B-group vitamins and of C and D vitamins, oxidative stress, metabolic acidosis and low-grade inflammation. In particular, in hemodialysis (HD) adult patients, an impairment of nutritional status has been observed, induced not only by the HD procedures themselves, but also due to numerous CKD-related comorbidities. The alteration of nutritional assessment induces systemic manifestations that have repercussions on oral health, like oral microbiota dysbiosis, slow healing of wounds related to hypovitaminosis C, and an alteration of the supporting bone structures of the oral cavity related to metabolic acidosis and vitamin D deficiency. Low-grade inflammation has been observed to characterize periodontal diseases locally and, in a systemic manner, CKD contributes to the amplification of the pathological process, bidirectionally. Therefore, CKD and oral disease patients should be managed by a multidisciplinary professional team that can evaluate the possible co-presence of these two pathological conditions, that negatively influence each other, and set up therapeutic strategies to treat them. Once these patients have been identified, they should be included in a follow-up program, characterized by periodic checks in order to manage these pathological conditions.

Hypertensive renal transplant recipients adhering to mediterranean diet present better periodontal status

Rationale: Previous studies showed negative effects of more advanced stages of periodontitis (chronic inflammation of gingival tissue and supporting bone structures) on renal transplant recipients (RTRs). Arterial hypertension (AH) and periodontitis share common comorbidities and are highly prevalent amongst RTRs which puts them at higher risk of developing cardiovascular diseases. Mediterranean Diet (MeDi) is useful to prevent the early onset of chronic non-transmittable diseases and plays an important factor in periodontal health status.

P30. Safe and improved spinal surgery using a new device in multiple indications

BACKGROUND CONTEXT Spinal procedures often require the removal of bony tissues to prevent nerve compression and reduce pain. In order to reach difficult-access spinal regions such as the foramen, the surgeon is often required to drill (or otherwise remove) through healthy supporting bone structures, therefore increasing the risk of spinal instability. PURPOSE This study describes the authors' experience with a recently developed, FDA-approved, curved-at-the-tip drill-like device, designed to provide efficient bone removal from difficult-access areas. The device is shielded on one side of the tip in order to improve safety and reduce the risk of complications. STUDY DESIGN/SETTING Multi-center retrospective study and surgeon questionnaire analysis. PATIENT SAMPLE Device-use patterns were extracted from 103 lumbar foraminotomies, 53 cervical osteophyte removals and 143 transforaminal lumbar interbody fusion (TLIF) procedures conducted using the device and 66 comparable control TLIF procedures conducted by the same surgeon group used as a control group. OUTCOME MEASURES Device-related dural tear rate, surgeon assessment of the procedure, duration of device use. For the TLIF procedures, OR time and length of stay were also compared with the control group. METHODS The rate of device-related dural tears was calculated from 1,116 safety records of procedures conducted using the device and compared with literature rates of traditional-tools device-related tears. Surgeon assessment was obtained using questionnaires at the end of each procedure. The duration of device-use, length of procedure and other operative and postoperative parameters were extracted from procedure records and reviewed where available. RESULTS The device-related dural tear rate was 0.3% (three tears in 1,116 procedures). This rate is significantly lower than the device-related tear rate of 2.9% associated with the Kerrison rongeur and high-speed drill published in a prior literature review. Surgeon satisfaction rate was 94% and sufficient bone volume reduction was reported in 95% of the procedures. Surgery time reduction was the most common comment in surgeon questionnaires. In some cases, of multi-level complicated fusions, the time reduction was estimated as several hours. Lumbar foraminotomy using the device required, on average, 2 minutes/foramen. In some of the cases, the device enabled the surgeon to avoid a spinal fusion as the improved access eliminated the need for excessive bone removal. Cervical osteophyte removal required, on average, three minutes, and in the majority of the cases enabled the surgeons to avoid additional level discectomy or corpectomy. TLIF procedures required on average 10 minutes less than control procedures with a 0.5 days reduction in length-of-stay. The device was successfully used in both open and minimal invasive settings without a significant difference between settings. CONCLUSIONS The device is safe and effective for performing spinal surgery in multiple indications. Procedure time reduction was noted as the most significant advantage by the surgeons. FDA DEVICE/DRUG STATUS Dreal (Carevature Medical Ltd.) (Approved for this indication)

ANALYSIS OF THE MECHANISM OF LUBRICATION OF THE TEMPOROMANDIBULAR JOINT

The aim of the work is to identify the lubrication conditions of the correct temporomandibular joint (TMJ) based on spatial modeling of joint structures, load simulations, reduced stresses, and resultant deformations in correlation with rheological parameters of synovial fluid. The material used in this study is the results of normal joint imaging performed using a standardized technique under occlusal conditions. Modeling and the simulation of contact, after the introduction of strength parameters of hard tissues, fibrous cartilage, and synovial fluid and the imposition of boundary conditions was carried out in the following program: Femap NE Nastran. Spatial simulation of contact between joint structures, virtual loading, and the visualization of what happens in the joint allows one to identify these structures in terms of tribology and strength. The transfer of loads in TMJ results from the geometric form of the supporting bone structures and joint surfaces, the distribution of the cartilage tissue building these surfaces, the geometry of the disc, and rheological parameters of the joint synovial fluid. In normal and loaded TMJ, differential displacement occurs in the joint cavity and cartilage structures, which stimulates the lubrication mechanism and optimize the use of synovial fluid properties. The joints are characterized by the absorption of maximum stresses reduced by bone structures. Load compensation and suspension is achieved by cartilage covering the joint surfaces and, to a large extent, by the joint disc and elastic-viscous response of a synovial fluid.

Vieillissement cutané – Vieillissement facial global : orientation thérapeutique

Correction of cutaneous and facial ageing is the key reason for consultations in aesthetic dermatology. This demand on the part of patients, which has become a social phenomenon, has increased thanks to the remarkable progress made in nonsurgical and less invasive therapies such as lasers, botulinum toxin and fillers. But in order to optimise their use and to provide a personalised touch, since each face ages differently, an overall facial analysis, both static and dynamic, is essential. Indeed, ageing is obviously not restricted to skin but also concerns underlying tissue such as muscle, fat tissue and supporting bone. In this article, we provide a clinical and physiopathological analysis of the ageing of skin and of the various types of ageing, whether chronological, hormonal or environmental, and we examine the major role played by UV radiation, as well as tobacco smoke and, in certain cases, pollution. The description of cutaneous ageing covers not only the face, in which photoaging is the predominant factor, but also ageing of skin throughout the rest of the body. Next we describe the general modes of facial ageing for the subcutaneous structures, first those of the skin muscles, which compensate for their atrophy by means of permanent hypercontraction that result in dynamic wrinkles, then those of fat tissue in which ptosis can occur, coupled in some cases with atrophy and loss of the fullness and harmonious facial curves of youth, and those of supporting bone structures and preferential areas of resorption, which are also where the most pronounced ageing of soft tissue is discernible. The upper third, middle and lower third of the face do not age in the same way and the relevant methods of correction thus differ. Finally, we briefly discuss the therapeutic choices available, taking into account the generally extremely reasonable expectations of patients, who tend to seek moderate and natural rejuvenation in keeping with their personality, as well as the elimination of negative expressions associated with ageing, and who want neither a rigid face nor aesthetic cloning.

Vertical 3D Bone Reconstruction with Simultaneous Implantation: A Case Series Report.

Tooth loss generally leads to a corresponding loss of supporting bone structures, jeopardizing correct implant placement. Bone augmentation procedures facilitate reconstruction of the alveolar contours but lengthen treatment time by about 4 to 9 months. The aim of this case series report is to describe the short-term results of the combination of three-dimensional bone augmentation using the shell technique in conjunction with simultaneous implantation. A total of 10 patients who underwent autologous bone augmentation using the shell technique with simultaneous implantation were retrospectively examined. The shell technique is an augmentation procedure using thin cortical bone plates adapted to the buccal and oral walls of the defect to rebuild the contours of the alveolar ridge. The remaining spaces are filled with bone chips. Healing time before second stage surgery was 4 months. The vertical bone defect at the beginning (VD), the height of the vertical bone graft, resorption at the time of second-stage surgery (BR1) and 1 year after prosthetic rehabilitation (BR2), the total resorption between augmentation and 1 year (BRtot), and the vertical bone loss of the implant (VBL) were measured. VD was 3.1 mm. Values for BR1 and BR2 were 0.4 and 0.45 mm, respectively, resulting in a total bone loss of 0.85 mm of bone loss (BRtot). VBL was 0.45 mm 1 year after prosthetic rehabilitation. The simultaneous approach of vertical bone augmentation in the shell technique and implantation shows excellent results in bone reconstruction and stability up to 1 year after prosthetic reconstruction and can shorten treatment time by 4 to 9 months.

Brief communication: Comparing loading scenarios in lower first molar supporting bone structure using 3D finite element analysis

Finite element analysis (FEA) is a widespread technique to evaluate the stress/strain distributions in teeth or dental supporting tissues. However, in most studies occlusal forces are usually simplified using a single vector (i.e., point load) either parallel to the long tooth axis or oblique to this axis. In this pilot study we show how lower first molar occlusal information can be used to investigate the stress distribution with 3D FEA in the supporting bone structure. The LM(1) and the LP(2) -LM(1) of a dried modern human skull were scanned by μCT in maximum intercuspation contact. A kinematic analysis of the surface contacts between LM(1) and LP(2) -LM(1) during the power stroke was carried out in the occlusal fingerprint analyzer (OFA) software to visualize contact areas during maximum intercuspation contact. This information was used for setting the occlusal molar loading to evaluate the stress distribution in the supporting bone structure using FEA. The output was compared to that obtained when a point force parallel to the long axis of the tooth was loaded in the occlusal basin. For the point load case, our results indicate that the buccal and lingual cortical plates do not experience notable stresses. However, when the occlusal contact areas are considered, the disto-lingual superior third of the mandible experiences high tensile stresses, while the medio-lingual cortical bone is subjected to high compressive stresses. Developing a more realistic loading scenario leads to better models to understand the relationship between masticatory function and mandibular shape and structures. Am J Phys Anthropol, 2012. © 2011 Wiley Periodicals, Inc.

The Effect of Framework Design on Stress Distribution in Implant-Supported FPDs: A 3-D FEM Study

The biomechanical behavior of the superstructure plays an important role in the functional longevity of dental implants. However, information about the influence of framework design on stresses transmitted to the implants and supporting tissues is limited. The purpose of this study was to evaluate the effects of framework designs on stress distribution at the supporting bone and supporting implants. In this study, the three-dimensional (3D) finite element stress analysis method was used. Three types of 3D mathematical models simulating three different framework designs for implant-supported 3-unit posterior fixed partial dentures were prepared with supporting structures. Convex (1), concave (2), and conventional (3) pontic framework designs were simulated. A 300-N static vertical occlusal load was applied on the node at the center of occlusal surface of the pontic to calculate the stress distributions. As a second condition, frameworks were directly loaded to evaluate the effect of the framework design clearly. The Solidworks/Cosmosworks structural analysis programs were used for finite element modeling/analysis. The analysis of the von Mises stress values revealed that maximum stress concentrations were located at the loading areas for all models. The pontic side marginal edges of restorations and the necks of implants were other stress concentration regions. There was no clear difference among models when the restorations were loaded at occlusal surfaces. When the veneering porcelain was removed, and load was applied directly to the framework, there was a clear increase in stress concentration with a concave design on supporting implants and bone structure. The present study showed that the use of a concave design in the pontic frameworks of fixed partial dentures increases the von Mises stress levels on implant abutments and supporting bone structure. However, the veneering porcelain element reduces the effect of the framework and compensates for design weaknesses.

Development of 3D CAD/FEM Analysis System for Natural Teeth and Jaw Bone Constructed from X-Ray CT Images

A three-dimensional finite element model of the lower first premolar, with the three layers of enamel, dentin, and pulp, and the mandible, with the two layers of cortical and cancellous bones, was directly constructed from noninvasively acquired CT images. This model was used to develop a system to analyze the stresses on the teeth and supporting bone structure during occlusion based on the finite element method and to examine the possibility of mechanical simulation.

Visualization of osseointegration of maxilla and mandible dental implants

We present a new, hybrid visualization method that can assist in assessing the degree of osseointegration of dental implants. The method is based on radiographic imaging, three-dimensional (3-D) volume reconstruction, and color coding of bone density. It provides both a 3-D image of the titanium implant and the implant site, and a two-dimensional (2-D) profile of the lingual and buccal sides of the implant, exposing possible weaknesses in the supporting bone structure. The visualization procedure described here consists of 2-D cross-sectional CT imaging, 3-D gradient-based hardware-accelerated volume rendering using 3-D texture mapping, implant site extraction using 3-D selection of a 2-D cross-sectional, tri-linearly interpolated 2-D image, computation of a bone density profile and line integral along the implant, and 3-D hybrid rendering of the implant site and the derived bone density information in its anatomical context. This method has been demonstrated to be successful in enabling the mapping of information derived from virtual bone density measurements onto a geometric object, thus providing the necessary information to relate other information from mechanical testing or simulations to the respective site. A high-resolution scan of a cadaver was used as a reference data set. The hybrid view, a combination of 2-D density profile and 3-D color-coded density rendering, turned out to be very intuitive and easy to interpret. The 2-D view was also useful for relating standard 2-D X-ray imaging with enhanced 3-D imaging of bone density. On top of this, our image-based method was used for cross-validation of a mechanical testing method. It turned out that the results from mechanical testing of osseointegration were very well correlated with the results from our image-based 2-D and 3-D methods. Since these two methods work in completely different ways (mechanical vs. radiographic) and the results came out are the same, the results provide evidence that both methods for assessing the degree and location of osseointegration are valid. Further studies using additional scans on living subjects will be conducted to provide additional evidence. Cost-efficient X-ray imaging can be used to replace the simulated implant-aligned 2-D X-ray views that were obtained from a 3-D scan.

The effect of thread design on stress distribution in a solid screw implant: a 3D finite element analysis

The biomechanical behavior of implant thread plays an important role on stresses at implant-bone interface. Information about the effect of different thread profiles upon the bone stresses is limited. The purpose of this study was to evaluate the effects of different implant thread designs on stress distribution characteristics at supporting structures. In this study, three-dimensional (3D) finite element (FE) stress-analysis method was used. Four types of 3D mathematical models simulating four different thread-form configurations for a solid screw implant was prepared with supporting bone structure. V-thread (1), buttress (2), reverse buttress (3), and square thread designs were simulated. A 100-N static axial occlusal load was applied to occlusal surface of abutment to calculate the stress distributions. Solidworks/Cosmosworks structural analysis programs were used for FE modeling/analysis. The analysis of the von Mises stress values revealed that maximum stress concentrations were located at loading areas of implant abutments and cervical cortical bone regions for all models. Stress concentration at cortical bone (18.3 MPa) was higher than spongious bone (13.3 MPa), and concentration of first thread (18 MPa) was higher than other threads (13.3 MPa). It was seen that, while the von Mises stress distribution patterns at different implant thread models were similar, the concentration of compressive stresses were different. The present study showed that the use of different thread form designs did not affect the von Mises concentration at supporting bone structure. However, the compressive stress concentrations differ by various thread profiles.

Three-dimensional visualization of the face and skull using computerized tomography and laser scanning techniques.

This paper describes the use of a specially designed no contact laser scanning system and Computerized Tomography (CT) for studying changes in the facial form and its relationship to changes in the supporting bone structure after facial surgery. It is shown that realistic images may be produced from these data sets using computer graphics techniques to give the images a solid 3-D appearance. The images may then be used for planning surgery and to provide the patient with a prediction of facial appearance after surgery. A number of such images are presented.

Occlusal interferences related to dental panoramic radiographic changes in subjects treated with fixed prosthesis

Because of contradictory reports between clinical and radiographic findings, occlusal analysis correlated to dental panoramic findings was completed in 147 patients treated with fixed prosthesis. Both occlusal interferences and radiographic changes in the TMJ area and/or in dentition were frequently discovered. Dysfunction and occlusal indices gave statistically significant correlations to radiographic changes (P less than 0.01 and P less than 0.05, respectively) in the TMJ area. Periodontal changes with vertical bone pocket formation and sclerotic lamina dura seem to be early radiographic findings and occlusal interferences were the only means to give a clear-cut correlation to the radiographic changes (P less than 0.001). However, if periodontal tissues with supporting bone structure fail to respond to occlusal trauma, changes in the TMJ area will probably appear. From the clinical changes the deviation on mouth opening, tenderness to palpation of TMJ, and slide from retrusion to intercuspidation (RP-IP) explained most of the radiological TMJ changes when tested by the discriminant analysis. The value of radiographic follow-up of subjects following prosthetic treatment is emphasized.

Three-dimensional visualization of the face and skull using computerized tomography and laser scanning techniques

This paper describes the use of a specially designed no contact laser scanning system and Computerized Tomography (CT) for studying changes in the facial form and its relationship to changes in the supporting bone structure after facial surgery. It is shown that realistic images may be produced from these data sets using computer graphics techniques to give the images a solid 3-D appearance. The images may then be used for planning surgery and to provide the patient with a prediction of facial appearance after surgery. A number of such images are presented.

Enamel-bonded immediate tooth replacement

A significant problem which faces the orthodontist from time to time is that of the patient who suffers the sudden loss of an anterior tooth. All too often, it seems, this occurs just as highly favorable orthodontic treatment is being concluded. Most often the course of such a situation is traumatic evulsion or injury requiring extraction of the tooth. Regardless of the cause, it is an emergency situation and calls for immediate treatment. It is necessary for the lost tooth to be replaced to maintain arch form as well as to provide esthetic and psychological support to the patient. Often after active orthodontic treatment stabilizing appliances are worn for a period of time. At this stage immediate tooth replacement is necessary to support a functional retainer and prevent collapse of the case. With the loss of an anterior tooth, its temporary replacement is often accomplished by banding the adjacent teeth to support a pontic. The cosmetic result of such an appliance is highly undesirable. Should the patient be using a removable prosthesis, such as a Hawley retainer, a replacement can be added to it. This automatically limits its potential activity and requires the patient to be wedded to it, even if its use had previously been necessary only during the evening hours. In addition, the effect of a tissue-bearing prosthesis that is in constant contact with the soft interproximal tissues frequently results in a gingivitis and a loss of supporting bone structure. Also, the fastidious person has an ongoing problem maintaining good oral hygiene, especially if meals are taken in public restaurants. The discomfort experienced from entrapped particles of food and the taste and odor of the end products of putrefaction are a constant challenge. Among the many potential uses of the enamel-bonding technique, the luting or bonding’-” of single and multiple4 pontics has proved clinically successful. In vitro studies have corroborated these findings by ascertaining that the applied forces required to dislodge an anterior pontic is far greater than the forces normally experienced in mastication.” This method of immediate replacement of a missing anterior tooth thus can now be included as an alternative procedure in applicable cases. It has the advantage of being placed as soon as a dry field can be maintained following elimination of the tooth, and it is a chairside procedure, it is a reversible technique, it does

Effects of force direction on supporting bone during tooth movement

Photoelastic stress analysis by means of simulated load application on model structures was used to visualize the forces that are induced within the supporting bone structures during various tooth movements. A comprehensive picture of the stress patterns produced by these forces, in addition to the degree of stress distribution, was obtained. The results of this study are relevant to the basic tooth movement procedutes that are used by the clinician in general practice.

Immediate denture service designed to preserve oral structures

Advantages.—An immediate denture technique has been described that has the following advantages: 1. The immediate dentures can be inserted immediately after extraction without removing bone or soft tissue. 2. The ridges heal rapidly with a minimum of postoperative problems due to careful denture construction and minimal surgery. 3. The postoperative care is designed to preserve the supporting bone structure. Disadvantages.—The technique has the following disadvantages: 1. It requires careful attention to details and extensive cooperation of the oral surgeon, prosthodontist, and the patient. 2. It requires more time and planning by the prosthodontist than some other techniques. 3. The postoperative care must be painstakingly and patiently administered by the prosthodontist.