Demonstration of In Vitro Host-Guest Complex Formation and Safety of para-Sulfonatocalix[8]arene as a Delivery Vehicle for Two Antibiotic Drugs

The macrocycle para-sulfonatocalix[8]arene, sCX[8], was examined with 2 antibiotic drugs, ciprofloxacin (CIP) and isoniazid. The drugs were shown to form complexes with sCX[8] using proton nuclear magnetic resonance, thermogravimetric analysis, fluorescence spectroscopy, and molecular modeling. Both drugs form 1:1 hydrated (H₂O: 13%-14% w/w) host-guest complexes, with sCX[8] binding around the pyridine ring of isoniazid, and around the piperazine and cyclopropane rings of CIP. From proton nuclear magnetic resonance, the binding constant of isoniazid to sCX[8] was 6.8 (±0.3) × 10³ M^?1. Addition of 2 equivalents of sCX[8] to CIP resulted in a 58% decrease in fluorescence, and time-resolved fluorescence anisotropy of CIP doubles with sCX[8]. Each drug binds into the cavity of the macrocycle, with binding stabilized via combinations of hydrogen bonding, electrostatic interactions, π-π stacking, and hydrophobic effects. The safety of sCX[8] was examined in vitro with human embryonic kidney 293 cells. The IC₅₀ of sCX[8] was 559 μM, which is a minimum of 5-fold higher than the concentration that would be used in the clinic. The in vitro effect of sCX[8] on the action of CIP was examined on a panel of bacterial lines. The results showed that sCX[8] has no inherent antibiotic activity and had no negative effect on the action of CIP.     

Oral cancer. Practical prevention and early detection for the dental team

Approximately 2,000 patients a year are diagnosed with oral cancer in New York State. In an effort to control this deadly disease, Governor George Pataki has taken a leadership role in the United States by mandating and funding training for dentists in the prevention and early detection of oral cancer. The purpose of this article is to highlight the epidemiology of oral cancer, to show how the dental profession can contribute to the health of the citizens of New York State, and to provide practical guidelines for both tobacco cessation intervention and utilization of existing technology for the early detection of oral cancer and precancerous conditions in the general dental practice setting.     

Cervical impalement injury

Impacted injuries of the head and neck are uncommon. Associated injuries can be present and can be a serious problem. We present an unusual clinical case and discuss the management of this complex injury. Head and neck injuries deserve special attention because of their enormous functional and esthetic significance. Contusion, abrasion, retained foreign bodies, laceration, and avulsion are some of the most frequent injuries. Impalement injuries are not so common. These lesions combine aspects of blunt and penetrating trauma and usually result from penetration by a large, rigid, blunt-tipped object that traverses a certain body area in a through-and-through fashion and often remains in situ at the time of presentation. There have been many case reports describing these injuries in the trunk and extremities; however, cases of head and neck impalement are still lacking in number. A case of an unusual cervical impalement is presented, together with a discussion of the management of this complex injury.     

An ultrastructural analysis of the prototype single-step adhesive applied on enamel and dentin surfaces

A new type of self-etching agent, the single-step adhesive, was developed. The purpose of this study was to investigate the difference in the ultrastructural features of enamel and dentin surfaces following application of the prototype single-step adhesive (EXM618, 3M, MN, USA). Extracted caries-free human premolars were used in this study. Occlusal enamels of teeth--to be used as cut surface specimens--were removed perpendicular to the long axis of the specimens. The mesial and distal surfaces of these teeth, on the other hand, were used as uncut surface specimens in the test. In addition, Mega Bond (Kuraray Medical Inc., Tokyo, Japan) and Xeno CFII Bond (Dentsply Sankin, Tokyo, Japan) were used as controls. After covering half of the tooth surfaces with nail varnish (for control), the other half of each surface was treated with one of the three test adhesives--EXM618, Mega Bond, or Xeno CFII Bond--according to the manufacturer's recommendations. Conditioned enamel and dentin surfaces (i.e., decalcified depth and rugged surface) were observed with a scanning confocal laser microscope (SCLM 1100, Olympus, Tokyo, Japan; henceforth abbreviated as SCLM). Based on the findings of this study, the prototype single-step adhesive EXM618 appears to be suitable for use in dental clinics.     

Dental students' attitudes toward smoking cessation guidelines

Dentists can be effective in helping their patients achieve smoking cessation. To plan a didactic program, we explored the smoking cessation attitudes and practices of dental students and identified barriers to service provision in the dental setting. We assessed 244 fourth-year dental students at New York University College of Dentistry through a self-report survey. The instrument included a twenty-nine-item measure assessing attitudes towards tobacco-use counseling and adherence to National Cancer Institute tobacco cessation guidelines. The survey also assessed demographics, tobacco use history, and level of preparation to provide services. Generally, students endorsed tobacco prevention practices, but perceived barriers to service provision. Students provided counseling inconsistently, with 69 percent asking about smoking, 58 percent advising cessation, 24 percent offering assistance, and 22 percent providing followup on a routine basis. Those who provided more counseling were more likely to have undergone formal training in smoking cessation, did not feel time was a barrier to counseling, and had more favorable beliefs about dentists' role in promoting smoking cessation. Study findings indicate great receptivity among students as well as a critical need and opportunity to include comprehensive cessation counseling training in the dental curriculum.     

Biocompatibility of sealers used in apical surgery: a histological study in rat subcutaneous tissue

The aim of this study was to evaluate the biocompatibility of sealers used in apical surgery in rat subcutaneous tissue. Sterile polyethylene tubes were filled with the following sealers: Sealapex, Sealapex with addition of zinc oxide, Sealer 26, Sealer 26 with thicker consistency (greater powder-to-resin ratio) and White MTA. The tubes were implanted in the dorsum of male rats and after 7, 21 and 42 days, the animals were killed, obtaining 5 specimens for each sealer in each evaluation period. The lateral surface of the tube was used as negative control. The inflammatory reaction to contact with the sealers was classified as absent, mild, moderate and severe. At 7 days, all sealers caused similar inflammatory reactions in the connective tissue of the animals, with most specimens presenting a moderate to intense chronic inflammatory reaction, with presence of multinucleated giant cells. At 21 days, Sealer 26 and Sealer 26 with thicker consistency presented more intense inflammatory reaction (p=0.004), whereas after 42 days, the inflammatory reaction ranged from absent to mild with statistically similar results for both materials (p=0.08). Except for MTA, all sealers presented foreign-body granulomatous reaction at 42 days. All sealers but Sealapex presented a statistically significant decrease of the inflammatory reaction over time. In conclusion, all sealers caused moderate to severe inflammation in the earlier evaluation period. However, Sealer 26 and Sealer 26 with thicker consistency caused more intense inflammatory reactions after 21 days of contact with the tissues and no granulomatous reaction was observed for MTA at the final period of analysis.     

Analysis of the condyle/fossa relationship before and after prosthetic rehabilitation with maxillary complete denture and mandibular removable partial denture

STATEMENT OF PROBLEM: The influence of the loss of posterior teeth on the condylar position and on temporomandibular disorders (TMDs) remains a controversial issue. PURPOSE: This study investigated whether prosthetic rehabilitation promoted modification of the condylar position in subjects without symptoms of TMDs. MATERIAL AND METHODS: The temporomandibular joints (TMJs) of 12 women (age 37 to 74), all with existing maxillary complete dentures but no removable partial denture (RPD) restoring the Kennedy class I partially edentulous mandibular arch and no clinical signs of TMDs according to the criteria established by Helkimo, were viewed in maximal intercuspal position with corrected lateral tomography before and after prosthetic rehabilitation with a new maxillary complete denture and a mandibular RPD. Before prosthetic rehabilitation, a mandibular stabilizing base was fabricated to prevent the existing maxillary complete denture from dislodging during tomographic examination. Two methods were used to evaluate tomograms: (1) linear measurements of the subjective narrowest anterior and posterior intra-articular joint spaces made from the tomograms by use of a digital caliper and (2) linear measurements of the anterior and posterior intra-articular joint spaces on the basis of drawings and tracings. Repeated-measures analysis of variance followed by orthogonal contrasts were used to evaluate differences between measurements carried out on the same subject under the different test conditions of the study (before prosthetic rehabilitation, before prosthetic rehabilitation with a mandibular stabilizing base in position, and after prosthetic rehabilitation) (P<.05). RESULTS: Before prosthetic rehabilitation, a predominance of posterior condylar positions was observed. Before prosthetic rehabilitation with a mandibular stabilizing base in position, a significant decrease was observed in posterior condylar positions (P=.03). This decrease was more marked after prosthetic rehabilitation (P=.02). The subjective evaluation and comparison on the basis of drawings and tracings used to analyze the tomograms produced similar results (P=.70). CONCLUSION: Within the limitations of this study, significant changes in the condylar position occurred after prosthetic rehabilitation in subjects without symptoms of TMDs.     

Conversion from cyclosporin A to tacrolimus as a non-surgical alternative to reduce gingival enlargement: a preliminary case series

BACKGROUND: Gingival enlargement (GE) is a frequent side effect that occurs in organ transplant recipients (OTR) after the administration of cyclosporin A (CsA). The availability of new drugs used to suppress graft rejection in OTR offers an opportunity to manage GE non-surgically. This preliminary case series aimed to analyze the effect of CsA withdrawal and its substitution by another immunosuppressant in OTR with severe GE. METHODS: Four organ transplant recipients who had received a liver or renal allograft were recruited for this study. All OTR had developed clinically severe CsA-induced GE. GE scores were assessed for each patient at baseline and at weeks 2, 4, 8, 12, 16, and 54 following conversion to tacrolimus. Scaling and root planing were initially performed and repeated monthly during the first 6 months. Careful polishing of the teeth was carried out once every 2 weeks until month 6 and then monthly until month 12. Hygiene instructions and reinforcement to optimize oral hygiene were maintained throughout the study. RESULTS: The four patients showed a rapid decrease in their gingival symptoms and in the size of the gingivae. This change was clinically evident 8 weeks after conversion to tacrolimus. One year later, all the patients experienced GE regression, although some anatomic irregularities persisted in the interdental papillae of one of the patients. No adverse effects from tacrolimus were observed during the study except in one patient who presented headaches. CONCLUSION: It seems that CsA withdrawal and its conversion to tacrolimus in organ transplant recipients who develop severe gingival enlargement, together with an extensive plaque control program, provide an effective means to control/eliminate gingival hyperplasia, with minimal risk of graft dysfunction.