Affordable implant prosthetics using a screwless implant system

Many dentists have been reluctant to place dental implants because they have found that most implants are costly and time-consuming to place and have long-term maintenance problems. Most of these problems are caused by using screws to connect the abutment to the implant, the crown to the abutment or both. The use of a screwless implant system and conventional prosthetics, the author contends, can make implant dentistry affordable, versatile and easy to incorporate into all general dental practices.     

Implant-supported overdentures: the ZAAG attachment system

It has been amply demonstrated during the last decade that there are significant advantages to implant-supported overdentures beyond conventional complete dentures. Several attachment systems exist for connecting the overdenture to the implants, and practically all of them present notable benefits to the patients. This article discusses the use of the Zest Anchor Advanced Generation (ZAAG). This system, an outgrowth from the original Zest attachment, uses both individual implant attachments and bar attachments, and is compatible with all major implant systems. In addition to the retention, stability, and resiliency the ZAAG implant attachment system provides, it has the advantage of placing the resistance force of the attachment close to the implant body.     

A comparison of the effect of different occlusal forms in mandibular implant overdentures

STATEMENT OF PROBLEM: Posterior tooth form selection for implant overdentures is made according to personal preference and experience using the concepts of conventional complete denture prosthodontics. PURPOSE: This study (1) compared the masticatory efficiency of three occlusal forms, 0 degrees, 30 degrees, and lingual contact (lingualized occlusion), in subjects with mandibular implant overdentures, and (2) determined their effects on the implant supporting tissues. MATERIAL AND METHODS: Eight patients who had four root form implants in the mandibular symphysis area connected with a Hader bar were selected. Maxillary and mandibular dentures were constructed for each patient with interchangeable posterior segments and the three occlusal forms were tested. The masticatory efficiency for each posterior tooth form was assessed with objective food tests and a subjective patient preference questionnaire. Periodic evaluation of implant-supporting tissues also was performed. RESULTS: Reliability analysis showed that all R1 coefficients were > or =0.80 (<0.001), indicating high subject consistency between multiple chewing efficiency trials. MANOVA analysis indicated a significant difference in chewing efficiency among the three occlusal forms (p < 0.001). The 0 degree occlusal form was associated with a significantly higher number of chewing strokes compared with 30 degrees or lingualized occlusal forms. The different occlusal forms were not found to have a clinically detrimental effect on the peri-implant soft or hard tissues. CONCLUSION: Chewing efficiency tests and patient preference ratings showed that 30 degree teeth and lingual contact provided better chewing efficiency than 0 degree teeth. None of the tested occlusal forms showed any clinical or radiographic detrimental effect on the implant-supporting tissues.     

Reflections on external circulatory assistance. Apropos of 8 patients treated with the MEDOS system

Mechanical circulatory support is required when cardiogenic shock is unresponsive to well conducted medical therapy. In this hemodynamic situation, when the patient's life is in danger, within hours, several questions should be answered quickly. These questions take into consideration the etiologies of cardiogenic shock and are related to the possibility of improvement of myocardial function, cardiac transplantation, the choice of uni- or biventricular support and surgical techniques of left ventricular assistance (left atrium to aorta or left ventricular apex to aorta). The follow-up of patients with circulatory support is complex. It requires to take into consideration hemodynamic, mechanical and hemobiological parameters as well as the peripheric organ function. We report in this article our clinical experience with eight patients that underwent circulatory support with Medos external ventricular assist device.     

Observations on the vertebro-basilar system studied by ultrasound

Vertebro-basilar circulation is complex because conditioned by several factors. Ultrasounds allow the study of many of its aspect, both hemodynamic and anatomical. Data were obtained from the examination of 50,000 patients over 25 years, of which the last 1,000 patients were examined by means of transcranial Doppler, duplex scanner color and power. 40% of these patients were found normal, 20% only had arterial thickening, 26% various types of stenosis, 10.6% subclavian steal, 14% short vertigo. The basilar artery (BA) flow (230 ml/min +/- 40) is similar to that of the internal carotid (245 ml/min +/- 50). In elderly patients, the absence of a posterior communicating artery (28%) or of both arteries (13%) is more frequent than the absence of the anterior communicating artery (7%). In normal patients decubitus variations do not modify the BA flow. In patients with vertigo due to decubitus variations, BA flow velocity increases from 20% to 40% during vertigo. Subclavian steal completely modifies the hemodynamics of vertebral arteries, while in the BA it can vary in part or completely. In conclusion, vertebral hemodynamics is different from BA hemodynamics. BA must be considered as one side of the Willis' polygon because it is an anastomosis between the vertebral arteries and is a "hemodynamic damper" between intracranial and extracranial circulation.     

Comparing the behavior of children treated using general anesthesia with those treated using conscious sedation

The histopathologic study was performed to elucidate whether the fiber type atrophy of the vastus lateralis muscle in patients with hip or knee joint disorders is related to the activities of daily living (ADL) or habitual physical activity. Subjects were 16 female patients, 52.4 +/- 16.0 yr of age (mean +/- standard deviation), who underwent a vastus lateralis muscle biopsy at the time of total hip or knee replacement. At the time of referral to the rehabilitation center, the Functional Independence Measure (FIM) motor score and habitual physical activity at home were evaluated, and the diameter and atrophy factor for each muscle fiber type were measured on the histopathologic preparations of the biopsied muscles. The data were analyzed using ttest, one-way analysis of variance (ANOVA), Kruskal-Wallis one-way ANOVA, Spearman's correlation coefficient, and partial correlation coefficient. The patients showed muscle fiber atrophy and small angular fibers, and the atrophy factor was significantly increased in type 1, 2A, and 2B fibers, in that order (one-way ANOVA, P < 0.05). The patterns of the fiber type atrophy, consisting of normal, type 2B atrophy, type 2AB atrophy, and type 1 and 2AB atrophy, had a significant relationship with the fiber type atrophy (Spearman's correlation coefficient; rho = 0.834, P < 0.001). The FIM motor score showed a significant correlation with the atrophy factor (r = -0.584, P < 0.05), and significant differences were recognized among the four patterns of the fiber type atrophy (Kruskal-Wallis one-way ANOVA, P < 0.05). In conclusion, the muscle atrophy and patterns of the fiber type atrophy of the vastus lateralis muscle in patients with joint disorders may be related to changes in the FIM motor score.     

Risk stratification of patients with medically treated unstable angina using exercise echocardiography

The effect of high-dose irradiation on the migration of dioctyl adipate (DOA) and acetyl tributyl citrate (ATBC) plasticizers from food-grade poly (vinyl chloride) (PVC) and poly (vinylidene chloride/vinyl chloride) (PVDC/PVC) copolymer (Saran) films, respectively, into olive oil was studied. The results showed a significantly higher amount of DOA migrated into olive oil from irradiated versus nonirradiated samples. This difference was more noticeable in oil samples collected during initial periods of contact. The amount of DOA migrating into olive oil was lower for samples irradiated at a dose of 20 kGy in comparison with samples irradiated at a dose of 50 kGy. At a sampling time of 1 h the amount of DOA that migrated into olive oil was 93.9 mg/liter, 141.5 mg/liter, and 183.4 mg/liter for nonirradiated samples, 20-kGy irradiated samples, and 50-kGy irradiated samples, respectively. After 288 hr (12 days) of oil-film contact the respective amounts were 390.8 mg/liter, 409.2 mg/liter, and 430.1 mg/liter. There were no statistically significant differences in migrating amount of ATBC between nonirradiated samples and samples irradiated at a dose of 20 kGy, while in samples irradiated at a dose of 50 kGy the migration of ATBC was increased. After 1 h of oil-film contact no detectable amounts of ATBC had migrated. After 288 h of contact the amounts of ATBC that migrated into olive oil were 3.59 mg/liter, 3.56 mg/liter, and 4.12 mg/liter for nonirradiated samples, 20-kGy irradiated samples, and 50-kGy irradiated samples, respectively. It is suggested that plasticized PVC should not be used in direct contact with high-fat foodstuffs with or without irradiation treatment.     

Coagulation system in patients with blood malignancies treated with estrogens in the course of cytostatic therapy

Hospital managers initiate a nurse orientation program modeled after critical pathways. The structure allows them to assess nurses' competency while providing experience.     

Serological follow-up of patients with paracoccidioidomycosis treated with itraconazole using Dot-blot, ELISA and western-blot

Twenty-seven mycologically proven cases of paracoccidioidomycosis (PCM) were treated with itraconazole (100-200 mg/day in month 1 and 100 mg/day until month 6-8) and evaluated clinically and serologically, up to 3.5 years post-therapy, using Dot-blot and ELISA for measuring the titers of IgG, IgA and IgM anti-P.brasiliensis antibodies and Western-blot for determining IgG, IgA and IgM antibodies against the antigen components of the fungus. Before treatment, 81.5% (Dot-blot) and 84% (ELISA) of the patients presented elevated IgG anti-P.brasiliensis antibody titers which dropped slightly with treatment. On the other hand, the percentages of pre-treatment high-titered sera for IgA and IgM anti-P.brasiliensis were lower (51.9% and 51.8%: Dot-blot; 16.5 and 36%: ELISA, respectively) but the titers tended to become negative more frequently with treatment. Prior to treatment, the percentages of positivity for IgG, IgA and IgM anti-P.brasiliensis antibodies in Western-blot were 96%, 20.8% and 41.6%, respectively. Antigens with molecular weights varying from 16-78 kDa, from 21-76 kDa and from 27-78 kDa were reactive for IgG, IgA and IgM antibodies, respectively. The most frequently reactive antigenic components had molecular weights of 27, 33 and 43 kDa for IgG, and 70 for IgA and IgM antibodies. During the period of study, the patients responded well to treatment. The present data confirm the diversity and complexity of the humoral response in PCM, and the importance of utilizing different serological tests to detect IgG, IgA and IgM anti-P. brasiliensis antibodies.     

Experience with the Br?nemark implant system: 1985-1995

The osseo-integrated dental implant programme started at the University of the Witwatersrand, Johannesburg in 1985. This retrospective study describes the experience gained in the Division of Maxillofacial and Oral Surgery and the Department of Prosthetic Dentistry with the Br?nemark implant system. The numbers of fixtures placed, the types of prostheses prescribed and the surgical and prosthodontic successes and problems are described. The results of implant treatment have improved, and follow a marked learning curve.     

Observations on the microstructure and orientation relations in the vanadium-hydrogen system

Observations on the microstructure and orientation relations in the V-H system were made using optical, X-ray, and electron microscopy techniques. In the two phase α+ β region the axes of the β (bct) vanadium hydride were shown to be slightly tilted away from the cube axes of the α (bcc) vanadium. Metallographie observations of a polished (100) crystal showed two different surface features associated with the formation of the β hydride depending on the concentration. In the two phaseβ + γ region the orientation relation between the β(bct) phase and the γ (fcc) phase is such that the (100)_γ || (110)r and [001]_γ || [001]_γ.     

Influence of implant location on the mechanical characteristics using the transcortical model

Mechanical evaluation of implants harvested following surgical implantation is often performed as part of the screening process for new materials or surface textures. The question of randomization with respect to implant placement often arises when attempting to design a study to evaluate several implant types, while minimizing the number of animals required to perform the investigation. The purpose of this study was to analyze the effects of implant placement within the canine femur on mechanical characteristics of the bone-implant interface when using the transcortical model. Both smooth and porous-surfaced implants were evaluated at several time periods to determine the effects of placement in the medial versus left cortex, proximal versus distal placement, and left versus right femur. The smooth-surfaced implants demonstrated a significant effect due to proximal versus distal placement within the femur only. There were no other significant comparisons. Porous-surfaced implants demonstrated no significant effects due to placement within the femur. The results demonstrate the necessity for careful study design when evaluating smooth surfaced implants; however, paired comparisons in either the medial versus lateral cortex or left versus right femur will provide unbiased comparisons between the implants.     

Monitoring of lectin-reactive alpha-fetoproteins in patients with hepatocellular carcinoma treated using transcatheter arterial embolization

We investigated hemostatic abnormalities in 37 patients with deep vein thrombosis (DVT) and pulmonary embolism (PE) (PE patients) and in 40 patients with DVT without PE (DVT patients). Plasma fibrinogen, thrombin-antithrombin complex (TAT), plasmin-plasmin inhibitor complex, fibrin-D-dimer, activated protein C (APC)-protein C inhibitor (PCI) complex, von Willebrand factor (vWf), tissue plasminogen activator (t-PA), PA inhibitor-I (PAI-1), and thrombomodulin levels in both PE and DVT patients were significantly increased compared with normal volunteers. Plasma APC-PCI complex, PAI-1, and vWf levels in PE patients were significantly higher than those in DVT patients without PE. These findings indicate that PE patients are more hypercoagulable and hypofibrinolytic than DVT patients. Plasma TAT, APC-PCI complex, PAI-1, and vWf levels were the most sensitive indicators for PE. In these patients, increases in TAT and APC-PCI complex suggest DVT and increased PAI-1 and vWf suggest the risk of onset of PE.     

Initial clinical experience with the Ahmed Glaucoma Valve implant in pediatric patients

There is evidence that a low-density lipoprotein (LDL) subfraction profile of increased concentrations of small, dense LDL particles is less common among trained than among sedentary normocholesterolemic men, but it is still uncertain whether there is a similar association in hypercholesterolemia also. Therefore, we determined the lipid and apolipoprotein concentration and composition of six LDL subfractions (density gradient ultracentrifugation) in 20 physically fit, regularly exercising (>three times per week) hypercholesterolemic men and 20 sedentary hypercholesterolemic controls. Trained (maximal oxygen consumption [VO2max], 57.3 +/- 7.4 mL/kg/min) and sedentary (VO2max, 37.5 +/- 8.8 mL/kg/min) individuals (aged 35 +/- 11 years; body mass index [BMI], 23.9 +/- 2.7 kg/m2) were matched for LDL apolipoprotein (apo) B levels (108 +/- 23 and 112 +/- 36 mg/dL, respectively). Trained subjects had significantly lower serum triglyceride (P < .05) and very-low-density lipoprotein (VLDL) cholesterol levels (P < .05) and higher high-density lipoprotein 2 (HDL2) cholesterol levels (P < .01) than sedentary controls. LDL particle distribution showed that trained individuals had significantly less small, dense LDL (d = 1.040 to 1.063 g/mL) and more large LDL (d = 1.019 to 1.037 g/mL) subfraction particles than sedentary controls, despite equal total LDL particle number. Analysis of LDL composition showed that LDL particles of hypercholesterolemic trained men had a higher free cholesterol content than LDL of untrained hypercholesterolemic men. Small, dense LDL in hypercholesterolemic trained men were richer in phospholipids than those in sedentary controls. These data demonstrate the significant influence of aerobic fitness on lipoprotein subfraction concentration and composition, thereby emphasizing the role of exercise in the treatment and risk reduction of hypercholesterolemia.     

Predictive factors for speech perception in patients with cochlear implant

Cochlear implant therapy is an epoch-making advance in artificial sensory organ transplants, but the positive effects on speech perception vary. Quantification theory type I, a multivariate analysis, was used to determine predictive factors for speech perception in patients with cochlear implants. Fifty-one postlingual deaf adults (18 male and 33 female, mean age, 53.4, mean duration of deafness, 8.6 years) were tested for speech perception three or more months after a Nucleus 22 channels cochlear implant. The cause of deafness in nine patients was labyrinthitis, ototoxicity in five, meningitis in three and unknown in the remaining 34. Speech perception was measured by vowel, consonant and word recognition using a live voice, and monosyllable, word and sentence recognition using a videodisc. All tests were administered in a sound only condition. Results of the univariate analysis indicated that age at implantation was correlated with monosyllable recognition, and duration of deafness was correlated with live voice word recognition. Residual hearing and coding strategy were both correlated with all outcome measures. The multivariate analysis revealed that coding strategy, duration of deafness, residual hearing and the number of electrodes were significant predictors of live voice word recognition in that order.     

Periodontal repair in intrabony defects treated with a calcium carbonate implant and guided tissue regeneration

OBJECTIVE: To determine mortality and factors that might predict outcome in severe community-acquired pneumococcal pneumonia treated by a standard protocol. DESIGN: Prospective, non-concurrent study. SETTING: Respiratory intensive care unit (ICU) in a teaching hospital. PATIENTS: 63 patients who were diagnosed by positive blood culture or Gram stain and culture of sputum or tracheal aspirate were included. MEASUREMENTS AND RESULTS: Clinical features, severity scores including Acute Physiology and Chronic Health Evaluation (APACHE) II, organ failure and lung injury scores, and the clinical course in the ICU were documented; 79% of patients required mechanical ventilation. Bacteraemia was present in 34 patients (54%); there were no distinguishing clinical features between bacteraemic and non-bacteraemic cases. The overall mortality was 21%, with only 5 deaths (15% mortality) in the bacteraemic group. Shock and a very low serum albumin (< 26 g/l) were the only clinical features that differentiated survivors from non-survivors; lung injury, APACHE II and multiple organ failure scores were all predictive of outcome. The positive predictive value and specificity in predicting death in individuals for the modified British Thoracic Society rule 1 were 26 and 64%; APACHE II > 2057 and 88%; > 2 organ failure 64 and 92%; and lung injury > 233 and 73%, respectively. CONCLUSIONS: These results suggest that even in bacteraemic cases mortality should be below 25% with intensive care management and that conventional scoring systems, while predictive of group mortality, are unreliable in individuals.     

Periodontal repair in intrabony defects treated with a calcium sulfate implant and calcium sulfate barrier

THIS RANDOMIZED, CONTROLLED, CLINICAL STUDY was designed to evaluate outcome following surgical implantation of an allogeneic, freeze-dried, demineralized bone matrix-calcium sulfate (DBM+CS) composite with a CS barrier in intrabony periodontal defects. Twenty-six patients contributing 26 deep intrabony defects completed the study. Thirteen patients received the DBM+CS implant. Thirteen patients received gingival flap surgery alone (GFS; control). Clinical outcome was assessed at 6 and 12 months postsurgery. At 12 months postsurgery, probing depth (PD) reduction (mean +/-SD) for the DBM+CS and GFS group was to 4.3+/-0.5 and 3.0+/-1.3 mm; clinical attachment gain was to 2.9+/-0.8 and 1.7+/-1.5 mm; and probing bone level gain was to 2.9+/-1.4 and 1.2+/-1.2 mm, respectively. There were no apparent differences between evaluations at 6 and 12 months postsurgery. Clinical improvements were significantly different from presurgery for both groups at both observation intervals (P < 0.01). There were no significant differences between groups in PD reduction and clinical attachment gain. Probing bone level gain was significantly greater in the DBM+CS group compared to controls (P < 0.05). In summary, surgical implantation of DBM+CS with a CS barrier resulted in reduced PD and improved attachment levels comparable to that achieved by gingival flap surgery alone. However, gain in probing bone levels in deep intrabony periodontal pockets assessed by clinical parameters was greater than that observed by gingival flap surgery alone. These changes were noted at both 6 and 12 months after surgery. This regenerative technique needs further biologic evaluation before being generally accepted.