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.     

Chest pains in the dental environment

Chest pain does not necessarily indicate cardiac disease. The most common causes of acute chest pain encountered in dental situations include hyperventilation, pulmonary embolism, angina pectoris and myocardial infarction. Stress and fear often cause rapid breathing or hyperventilation. This usually occurs in young adults and although the hyperventilating patient often complains of chest pain, this is rarely a manifestation of cardiac disease. Pulmonary embolism usually indicates the occlusion of a pulmonary artery causing severe chest pain. The primary clinical manifestation of angina pectoris is chest pain. Although most instances of anginal pain are easily terminated, the dentist must always consider the possibility that the supposed anginal attack is actually a sign of acute myocardial infarction (AMI). AMI is a clinical syndrome caused by a deficient coronary arterial blood supply to a region of myocardium that results in cellular death. There is a high incidence of mortality among AMI with death often occurring within 2 hours of the onset of signs and symptoms. The initial clinical manifestations of all types of chest pain can be similar. Therefore the dentist must develop proficiency in constituting a differential diagnosis and an efficient management protocol. As in most medical situations prevention is the most powerful tool. However, if chest pains do occur, measures such as airway management, oxygen supplementation, coronary artery dilation, analgesis and in extreme cases, cardiopulmonary resuscitation and evacuation to the emergency room, may be necessary.     

Influence of pH and storage time on the sorption and solubility behaviour of three composite resin materials

OBJECTIVES: The aim of this study was to determine whether pH and time has any influence on the sorption and solubility behaviour of composite resin materials stored in a buffer solution. METHODS: Three hybrid composite restorative resin materials (Spectrum, Z-100 and ArtGlass) with different matrix structure and filler composition were studied. One hundred and twenty specimens of each material were produced according to ISO 4049. The materials were stored in McIlvain's buffer solution at different pH (4, 6 and 8) at 1, 7, 60 and 180 days. pH measurements were carried out before and after completed storage. RESULTS: Time had a significant influence on the sorption and solubility behaviour of the composite resin materials tested. One of the materials Z-100 showed a significant mass increase and/or decrease depending on the pH of the solution. The material Spectrum was significantly influenced by pH, resulting in different sorption depending on the pH of the solution. CONCLUSIONS: Time of storage was important for the sorption and solubility behaviour of the composite resin materials tested. Comparison of solubility for one of the materials showed twice as high values in the present study as previously reported when distilled water was used as storage medium. pH in the solution seems to have an influence on the sorption and solubility behaviour of composite resin materials. The sensitivity of the sorption and solubility behaviour to time and pH of the materials tested seems to be related to the hydrophilicity of the matrix and the chemical composition of the filler.     

Dental unit waterlines: review and product evaluation

Dental practitioners must be knowledgeable regarding microbial contamination and biofilm formation in dental unit waterlines. Education should stress the need for improvement in the quality of water delivered to patients during treatment. Manufacturers must also play an important role by providing training and education regarding the proper use and maintenance of their systems. Dental facilities, both public and private, need reliable methods to prevent the development of biofilms within DUWs. These methods must be economical and require minimal effort to use on the part of the dental staff. In order for the system to work efficiently, the effluent water that is produced must be compatible with dental materials and be potentially free from toxic or carcinogenic materials. There are numerous models of water filtration units and chemical flushes available to the dental practitioner. However, the Food and Drug Administration have not approved all products currently on the market. Our evaluation of Zerosil, a new waterline-cleaning product, indicates that it is very easy to use and is extremely effective in killing the commonly found microorganisms in dental unit waterlines, as well as eliminating existing biofilms. It is also economical and requires minimum staff time to keep the waterlines clean. Following the initial treatments during week one, the water emanating from the DUWs was free from any viable microorganisms. This effect was present the entire three weeks in which the waterlines were treated. The elimination of viable microorganisms continued into a fourth study week, even though no further treatment of the DUWs was performed. Although the manufacturer recommends weekly treatment of DUWs following the initial treatment regimen, this result indicates that the product has a longer lasting effect than previously thought. Finally, the product can be delivered through any of the commercially available reservoir/bottle water delivery systems. From our study, Zerosil appears to meet the demanding requirements of keeping dental unit waterlines clean. Based on the research that has been done thus far, no universal treatment protocol can be recommended. A combination of approaches may offer the best available assurance of high-quality dental treatment water. Independent water reservoir systems, when used with a periodic chemical treatment protocol, have demonstrated safety and efficacy. Until we reach a point when a recommendation based on thorough evaluations can be made, dental offices should follow current ADA, OSAP, and CDC guidelines: flush waterlines for two to three minutes at the beginning of each day and for 20 to 30 seconds between each patient, and anti-retraction valves should be installed to prevent oral fluids from being drawn into dental waterlines. It is expected that in the near future, the dental practitioner will have a choice of proven systems and products to deal with this issue. Until that time, one should carefully evaluate any product or system being considered to prevent the formation of biofilms in DUWs.     

Regional wall motion abnormalities during early diastole in patients with hypertensive left ventricular hypertrophy: a Doppler tissue echocardiographic study

To investigate left ventricular wall motion asynchrony in patients with hypertensive heart disease, we measured regional myocardial velocity in hypertensive patients with left ventricular hypertrophy and in normotensive individuals using tissue Doppler imaging. The endocardial velocity and the myocardial velocity gradient were measured in the basal and mid segments of the septal and posterior walls. The dilating velocity of the left ventricular cavity were determined for the basal and mid ventricular segments of left ventricle. The peak myocardial velocity gradient was significantly lower in the hypertensive group than in the control group for all regions. The peak endocardial velocity during early diastole in the mid ventricular septum was significantly lower in the hypertensive group (Hypertensive vs Controls; 3.8 +/- 1.3 vs 5.1 +/1.6 cm/s, P < 0.05), whereas the peak endocardial velocity at the other three sites were similar in the two groups. The peak dilating velocity was significantly lower in the hypertensive group only in the mid portion of the left ventricle (Hypertensive vs Controls; 7.2 +/- 2.4 vs 9.8 +/- 1.3 s(-1), P < 0.005). These results suggest that there were regional wall motion abnormalities and nonuniformity during the early diastolic phase in the hypertensive hearts with left ventricular hypertrophy.