Quality of marginal adaptation evaluation of posterior composites in clinical trials

The evaluation of margins of restorations in clinical trials relies on the subjective assessment of evaluators, with no instrument having been developed, let alone validated, to assist in the process. The purpose of the present study was to assess the quality of evaluations of marginal adaptation by analyzing the distribution of marginal steps rated according to clinical criteria. Replicas of 435 restorations, the marginal qualities of which had been evaluated according to modified USPHS criteria, were randomly selected from the Occlusin multi-center clinical trial program. The marginal step height in the most deteriorated area of each restoration was measured by means of a digital step-height instrument. An overlap between the steps in the restorations with A (Alfa; replacement unnecessary) and B (Bravo; replacement questionable) ratings was found to be in the range of 101 microm to 321 microm. When the steps with a height greater or less than one standard deviation of the mean were excluded, the overlap was reduced to a range of 168 micro m to 173 microm. This finding indicates a marginal height boundary between A and B ratings for marginal adaptation of 170 +/- 3 microm.     

Characterization of the immunologic responses to human in vivo acquired enamel pellicle as a novel means to investigate its composition

Human acquired enamel pellicle is formed by molecules selectively adsorbed onto tooth surfaces. The present work describes the use of monoclonal antibody (mAb) technology as a novel approach to identify micro amounts of components present in pellicle. MAbs were obtained with reactivities against statherin, histatin, mucous glycoprotein 1(MGI), albumin, amylase and human immunoglobulins (Igs), indicating that these are pellicle components, which was further confirmed by immunoblotting. No mAbs against proline-rich proteins (PRPs), lysozyme, mucous glycoprotein 2 (MG2), carbonic anhydrase, lactoferrin or peroxidase were obtained, suggesting that these components are absent, present in low amounts, or exhibit low antigenicity. Further characterization of the binding epitopes of some of th e obtained anti-MGO, anti-statherin and anti-histatin mAbs were carried out and the biological relevance is discussed. The results open up the possibility that immunization with human pellicle and mAbs production can be employed to identify hitherto unknown constituents of pellicle.     

Incidence of penetration of a blood vessel during inferior alveolar nerve block

Aspiration of the syringe after the needle had been placed in position for an inferior alveolar nerve block (but before the anaesthetic solution was injected) in 250 patients showed that the tip of the needle was in a blood vessel in 49 (20%). Aspiration of blood was significantly more common in patients aged 9-19 years than in all others (P=0.04).     

Inhibitory effect of synthetic histatin 5 on leukotoxin from Actinobacillus actinomycetemcomitans

Actinobacillus actinomycetemcomitans is a gram-negative bacterium strongly implicated in the pathogenesis of juvenile periodontitis. This periodontal pathogen synthesizes a leukotoxin that destroys human polymorphonuclear leukocytes (PMNs), and this toxin is thought to be responsible for the virulence of A. actinomycetemcomitans. It was therefore of interest to assess whether major virulence factors of periodontal pathogens were neutralized by salivary components. This study focuses on the effect of histatins, components of the nonimmune oral defense system, on leukotoxin activity. Leukotoxin was extracted with polymyxin B from freshly grown anaerobic cultures of A. actinomycetemcomitans strain Y4. PMNs isolated from blood of healthy human volunteers were incubated in a cytotoxicity assay containing PMNs (10(7) cells/ml) and leukotoxin preparation (0-500 microg/ml) in Hanks' balanced salt solution at 37 degrees C for 0-120 min with or without synthetic histatin 5 (0-500 microM). Cytotoxicity was measured by release of lactate dehydrogenase (LDH) at different time intervals. Histatin 5 neutralized the toxic effect of the leukotoxin preparation in a concentration-dependent manner, with an IC(50) value of 150 microM. When PMNs were preincubated with histatin 5 (300 microM), washed and subsequently exposed to leukotoxin, no protective effect was observed. This observation suggests a mechanism of inhibition whereby histatin 5 either directly neutralizes the leukotoxin or interferes with the leukotoxin-PMN interaction. The inhibitory effect of histatin 5 on leukotoxic activity may suggest a new biological function of histatins in the oral cavity as a naturally occurring secondary antibiotic.     

Postoperative complaints following impacted mandibular third molar surgery in Ile-Ife, Nigeria.

An investigation into the pattern of complaints lodged by patients after impacted mandibular third molar surgery was done in a Nigerian teaching hospital over a period of 3 years. One hundred and twenty seven records were retrieved. Pericoronitis (71.2%), pulpitis (17.6%) and periodontitis (11.2%) were the reasons for surgery. No third molar surgery was done for prophylactic or orthodontic reasons. Sixty-one complaints were lodged by 49 (38.6%) patients on day 1, and 37 complaints by 35 patients on day 7. These complaints were verified by the findings of the examining clinician. Pain, swelling and trismus were the commonest complaints. A significant association (P = 0.042) was found between patients' complaints on the first postoperative day and the drug combination given. Similarly, there was a significant relationship (P = 0.0055) between the type of analgesics prescribed and the presence of postoperative pain. No significant relationship was however found between the complaints and patients' age, indication for extraction, impaction type and method of impacted tooth removal. Although the findings of this retrospective study are limited in their comparability, they suggest the need for an appraisal of pain management in patients undergoing mandibular third molar surgery in our hospital. Consequently, there should be a reduction in complaint rate thereby making selective review appointment on the first postoperative day feasible.     

Cerec 3 for orthodontics: a tool for treating deep bite

Bite-opening procedures are used in the early stages of orthodontic fixed treatment in order to: ease antero-posterior tooth movements; bracket the mandibular arch and level the Curve of Spee; prevent mandibular brackets from debonding; use regular straight archwires to proceed with treatment. For these purposes, removable or bonded biteplanes are universally recognized as very effective when the bite-opening is needed. Conventional orthodontic procedures include clinical solutions which effectively open the bite, but they all lack sufficient hygiene, comfort, and esthetics. The authors propose the use of the CAD-CAM technology with the Cerec 3 system (Sirona, Bensheim, Germany) to create an overcrown able to open the bite through clinical crown lengthening of the mandibular second premolars. The laboratory steps are described and the clinical efficacy is demonstrated with an orthodontic case report.