A Prospective Multicenter Study Evaluating Loading of Osseotite Implants Two Months After Placement: One-Year Results

Abstract: Historically, the recommended time between placement and functional loading of machined-surface dental implants has been 3 months for the mandible and 6 months for the maxilla. However, such recommendations are a result of evaluating randomly chosen healing times during the initial phase of implant development and are based on the subsequent clinical outcome of either implant integration or mobility. In recent years, histologic and experimental studies have shown that specifically designed micro-topographic implant surfaces can result in increased bone-to-implant contact at earlier healing times than obtained with machined-surface implants. Histologic and clinical studies investigating early and immediate implant loading support the premise that implants can be placed into function earlier than previously recommended. With the development of specifically designed implant surfaces and the utilization of time-saving surgical (one-stage surgical protocol) and prosthetic (implant position indexing) techniques, patients are now being restored and returning to function sooner than previously thought possible. The purpose of this multicenter clinical investigation is to evaluate the efficacy of loading Osseotite dental implants (3i-Implant Innovations Inc., Palm Beach Gardens, Florida) at 2 months and to determine the effect of early loading on implant performance and survival. A total of 429 Osseotite implants were placed in 155 patients (87 females and 68 males; mean age 54.0 ± 13.7 yr), at 10 study centers, and subsequently loaded 2.1 ± 0.7 months following placement. A single-stage surgical protocol was followed, with implants indexed immediately or impressed 4 to 6 weeks following placement. Patient restorative treatments included placement of 83 single-implant provisional restorations and 129 splinted, two-, three-, and four-implant supported maxillary and mandibular provisional restorations. The mean time from prosthetic loading to the most recent follow-up evaluation was 10 ± 1.3 months. Seven of the 429 implants did not integrate; of these, six were identified prior to loading and one was identified 1 month after loading. The cumulative implant survival rate was 98.5% at 12.6 months. The cumulative post-loading implant survival rate was 99.8% at 10.5 months. The preliminary results of this clinical investigation suggest that successful functional loading of the Osseotite dental implant is possible at 2 months following noncomplicated implant placement.     

Shear Bond Strengths of One-Bottle Adhesives to Moist Enamel

Abstract: Purpose: This study evaluated bond strengths of six one-bottle bonding agents and a control (primer plus unfilled resin) to moist enamel.
Materials and Methods: One-hundred and five bovine teeth were randomly assigned to seven groups of 15. Enamel was etched for 15 seconds with 35% phosphoric acid. Etched enamel was rinsed, and excess water was blotted with tissue paper. Following application of the adhesive, composite resin was bonded using a gelatin capsule technique. Shear bond strengths to enamel were determined using a universal testing machine (Instron Corp., Canton, Massachusetts).
Results: Mean bond strengths ranged from 21.9 MPa for OptiBond Solo (Kerr Corp., Orange, California) to 29.6 MPa for Prime & Bond 2.1 (Dentsply/Caulk, Milford, Delaware). Prime & Bond 2.1 had a significantly higher mean bond strength than the other adhesives.
CLINICAL SIGNIFICANCE: The results of this study suggest that all of the one-bottle systems tested should provide clinically acceptable bonding to moist enamel.     

Use of a Custom-Designed Adapter to Manage ICD Lead Fracture

We report the case of a 72-year-old patient with ischemic cardiomyopathy who was found to have a lead fracture in the RV coil DF-1 connector of an integrated bipolar implantable cardioverter-defibrillator (ICD) lead system at the time of upgrade to a biventricular ICD. Due to the redundant connection of the RV coil to the DF-1 connector and the ring on the IS-1 connector, a custom-designed adapter was used to exclude the site of fracture. This novel solution spared the patient the potential risks of lead extraction or abandoning the fractured ICD lead. In this way, pacing and defibrillating capabilities were fully restored, providing the patient 6 years of optimal device functioning.     

Transvenous Pacing in Children Weighing Less than 10 Kilograms

Pacemakers are used in small children with increasing frequency for the treatment of life-threatening bradyarrhythmias. The epicardial approach is generally preferred in these patients, to avoid the risks of vessel thrombosis. We examined the feasibility and safety of transvenous pacemaker implantation in children weighing <10 kg, via subclavian puncture, using a 4 Fr sheath introduced after a venogram was performed to evaluate the vein diameter. Progressive dilation with 5, 6, and 7 Fr sheaths preceded the insertion and placement of the endocardial lead. A subaponeurotic pocket was created in the abdominal or pectoral regions, depending upon the patient's size. Between 2001 and 2007, we treated 12 patients (median age = 16 months; range 1–32; median weight = 7.9 kg; range 2.3–10.0; 7 males), of whom four weighed <5 kg. Indications for permanent pacing included postsurgical complete atrioventricular block (n = 8), sinus node dysfunction (n = 2), congenital atrioventricular block (n = 1), and long QT syndrome (n = 1). Single-chamber pacemakers were implanted in 10, and dual-chamber pacemakers in two patients. The patients were evaluated at 48 hours, 10 days, and at 3 and 6 months. The mean follow-up was 31.8 ± 23.5 months. There were no procedural complications. Lead dislodgment occurred in one patient and required replacement of the ventricular lead. One patient died from septicemia. Endocardial pacemaker implantation was feasible and safe in children weighing <10 kg. This procedure is less invasive than the standard epicardial approach.     

Spinal Cord Stimulation for Severely Ischemic Limbs

Severe atherosclerosis of the lower limbs causes rest pain, skin ulcerations and gangrene. In such situations and when standard surgical treatment had failed or it is impossible to employ, spinal cord stimulation (SCS) seems to be of value. Since April 1985, we have used this technique on 19 patients. The results have been beneficial in 70.6% of the cases and have shown some evidence of increasing cutaneous flow. However, randomized series are required before accepting it as having a special place in the fight against atherosclerotic disease.     

Pyridoxine-Responsive Anemia: Report of 2 Cases in Brothers and a Review of the Literature

The clinical and laboratory findings in two brothers with severe anemiaare presented. These findings were very similar in both cases. Evidence thatat least one of them suffered from a pyridoxine-responsive anemia is presented.It was assumed that the other had the same disorder since, in addition to thestriking similarity in the clinical and laboratory abnormalities, the latter’s anemia disappeared completely with the parenteral administration of vitamin Bcomplex, which provided him with 2 mg. of pyridoxine daily. These patientshave not relapsed 1.5 and 6 years after stopping the therapy.

A review of the reported cases with anemia responding to vitamin B₆ administration is presented. Common factors observed in some of these casesare: (1) severe anemia, microcytic and hypochromic in type, chiefly due to astriking maturation erythroblastic arrest at the basophilic stage with no defectin leukocytes or thrombocytes; (2) hyperferremia and hemosiderosis; (3) anabnormal tryptophan-loading test; and (4) complete or almost complete correction of all abnormalities with administration of vitamin B₆, even at smalldoses. These data were considered to suggest that the patients had a true deficiency in pyridoxine.

In other patients, no increased excretion of xanthurenic acid has been observed after a tryptophan-loading dose, and pyridoxine administration hasimproved the anemia only partially and has not reversed the serum iron parameters to normality. All of these other patients suffered from a familial hypochromic anemia not due to iron deficiency or from a "sidero-achrestic" or "refractory normoblastic" anemia.

The cause of the disorder in patients in the first group is unknown, but, byexclusion, increased requirement of vitamin B₆ seems to be the most likelypossibility.

Submitted on November 22, 1960 Accepted on February 14, 1961     

Computer analysis of corneal innervation density using a novel double stain in rat corneal whole mounts

Computerised morphometry and a double stain technique were utilised to examine the corneal nerves in whole mounts. This novel stain combines the nonspecific acetylcholinesterase(NsAchE) and gold chloride(AuCl) procedures to enhance staining contrast and facilitate computerised detection of corneal nerves. Fresh rat corneas were dissected, and the Descemet's membrane-endothelium complex was removed. Then the corneas were fixed in 4% paraformaldehyde with 50 m m Na-K phosphate buffer (pH 7.2) and 8% sucrose for 30 min. They were rinsed and stained singly with NsAchE or AuCl, or were double stained using NsAchE followed by AuCl. Between NsAchE and AuCl staining the corneas were stored frozen in OCT compound at −70°C. Flat mounts of whole corneas were photographed before and after the second staining. Measurable stromal innervation density (mean± S.D. ) in age-matched corneas stained with AuCl(3.90±0.36 mm/mm²) was not significantly different from that of NsAchE stained corneas. However, double staining compared with NsAchE staining of the same corneas revealed a 48±27% increase in demonstrable innervation density of the subepithelial nerve plexus (7.95±0.86 mm/mm² vs 5.52±1.31 mm/mm², respectively). Improved visualisation of epithelial nerves and their fine ramifications (leashes) was also obtained by double staining. This novel combination of 2 procedures enhances the detection of corneal nerves for analysis by computerised morphometry and provides a more representative estimate of total corneal innervation density.