A comparison of endodontic treatment outcomes between HIV-positive and HIV-negative patients.

INTRODUCTION: There has been some surmise that immunocompromised patients may not be candidates for endodon tic therapy. AIM: To compare the clinical presentation, treatment, and treatment outcomes of HIV+ve and HIV-ve patients receiving endodontic therapy. METHOD: Fifty-nine HIV-ve and 46 HIV+ve patients who consented to join the study were sequentially selected from those presenting at the hospital. Clinical features were recorded for pain on palpation and percussion, thermal sensitivity, radiographic appearance, swelling, and time for treatment. Endodontic outcomes were assessed at 6, 12, 18 and 24 months. RESULTS: There was no statistically significant difference in the presenting signs and symptoms of the two groups, although HIV+ve patients reported more severe pain. HIV+ve patients presented with mainly anterior teeth requiring therapy, but only three teeth (24%) had caries. Active caries was present in 71% (42) of the HIV-ve patients and in only 7% (three) of the HIV +ve patients. Treatment time for comparable teeth in the HIV-ve patients (52 minutes) was nearly half that of the HIV+ve (112 minutes) patients, mainly due to the latter experiencing excessive canal bleeding during treatment. There was no significant difference in the final outcome at 24 months, though resolution of signs and symptoms tended to occur earlier in the HIV-ve patients. CONCLUSIONS: Endodontic therapy is not contra-indicated HIV+ve patients, although treatment times may be longer, and time to full resolution may take longer in some of these patients. A comparison of endodontic treatment outcomes between HIV positive and HIV negative patients.

On form and function in all-ceramic restorations.

All-ceramic restorations are achieving increasing popularity, partly because of the aesthetic demands of patients, but also because their increasing ease of fabrication and longevity compare favourably with the traditional plastic restorations in posterior teeth. The parallel development of cementation materials and bonding techniques has also improved longevity, although current evidence shows that posterior all-ceramic restorations have a slightly lower success rate than in anteriors, and the success rate falls with time. The purpose of this paper is to briefly review the evidence for the use of all-ceramic restorations particularly for posterior restorations on teeth, as well as to suggest that preparation form may need to change to take into account the properties of dental ceramics. In addition, a different approach to occlusal form is proposed, based on the evolution of form and function in dentitions, to suggest that the perfect reproduction of cusps and fissures may not be appropriate.

Stabilising a planning guide in post-mandibulectomy prosthodontic rehabilitation.

Patients presenting with grafted reconstructions of the mandible often lack anatomical features that allow for the consistent placement of a diagnostic denture and planning guide. The mucosa covering the graft appears flat with no discernible ridge form. A method was therefore adapted to provide stability to a guide for the placement of implants. A diagnostic denture was constructed to the try-in stage and duplicated in clear acrylic, with radio-opaque markers placed into potential implant positions. Three mini-implants (Southern implants, Irene, SA) were then placed under local anaesthetic trans-mucosally into the bone graft at positions corresponding to teeth 46, 31 and 36. Access holes were created in the flanges of the diagnostic denture/planning guide to enable it to seat over the mini implant heads and to allow for final positioning. Auto-polymerising resin was then placed to cover each of these heads, thus stabilising the guide. The patient was then referred for a CT scan, to be taken with the planning guide in situ, and a surgical guide was made from the CT data, which also used the mini implants for orientation. At surgery, this ensured the optimal placement of the definitive implants, and the mini-implants could then be removed. This method thus provides enormous beneft to both the planning for, and the placement of, implants into grafted bone in mandibulectomy patients.

Prosthodontic management of patients with amelogenesis imperfecta.

INTRODUCTION: Amelogenesis Imperfecta (AI) is an heterogenous genetic disorder that disturbs the developing enamel structure. This rare ectodermal defect leads to a variety of clinical manifestations due to agenesis, hypoplasia, and/or hypomineralisation of the enamel. AIMS AND OBJECTIVES: To describe the prosthodontic management of dental anomalies commonly associated with AI. METHODS: By using the classification of Witkop and Rao (1971), the variation in clinical presentation of the different Types of AI are illustrated and discussed, in particular Type I AI and Type 4 AI. RESULTS AND CONCLUSIONS: Early diagnosis and prosthodontic management as part of a multidisciplinary, patient-centred approach are key factors to treatment success. Treatment options to address the oral complications are influenced by modifying factors including age, socioeconomic status, type and severity of the disorder, and intraoral status at the time of treatment planning. Ultimately, management includes pain and infection control, provision of aesthetics and restoration of function which may lead to patient satisfaction, psychological well-being and an improved quality of life.

Antibiotic prophylaxis for dental procedures: is it necessary?

INTRODUCTION: Guidelines regarding the prevention of infective endocarditis have recently been published by the British Society for Antimicrobial Chemotherapy in 2006, the American Heart Association (AHA) in 2007 and the National Institute for Health and Clinical Excellence (NICE), UK, in 2008. These are contradictory, even though all are from developed countries. It is not known whether they are suitable for developing countries such as South Africa, nor is it known whether they are followed by general dental practitioners. AIMS AND OBJECTIVES: To conduct a survey amongst dental practitioners in South Africa to determine knowledge of the more recent AHA and NICE guidelines and the practices followed in antibiotic prophylaxis. METHOD: E-mails were sent to dentists registered with SADA requesting their participation in an internet-based survey. RESULTS: The limited response rate necessitated the pooling of the data, but it was felt they would be valuable if some trends emerged. Most (88%) of the 105 respondents were aware of the AHA guidelines, but only 55% knew of the NICE guidelines. However, few actually followed the recommendations and few correctly prescribed for patients allergic to penicillin. The large number of cases of rheumatic fever in this country implies that the AHA and NICE guidelines may not be appropriate. CONCLUSION: Despite the low sample size, the trends shown are of real concern. There is clearly a need for local guidelines, and once these are established, there is an urgent need to inform all dental practitioners of the appropriate prescription of prophylaxis for patients.

The need for versatility in the prosthodontic treatment of maxillofacial defects.

The main objective of this study was to survey the different maxillofacial defects of patients who presented to the Wits Dental Hospital and to review the methods that have been used to rehabilitate these patients. Forty six patient records were retrieved from patients' files and from final year reports of prosthodontic postgraduate students. The data were used to determine the type of maxillofacial defects that these patients suffered from and the treatment that had been carried out. Duration and cost of treatment was also noted. The study showed that the majority of the patients' defects were caused by cancer resections, followed by trauma, clefts, burns, and infection. Most patients received conventional 'appropriatech' treatments such as the use of adhesive-retained prostheses, whilst a small number received more sophisticated 'high tech' treatments of implant rehabilitation. The need for versatility in the prosthodontic treatment of maxillofacial defects.

Properties of a new mouthrinse for patients receiving radiation therapy.

INTRODUCTION: Patients receiving radiation therapy due to oral cancer develop complications such as hyposalivation, mucositis, oral infections, dental hypersensitivity and caries. Mouthrinses can alleviate some of these problems. AIMS AND OBJECTIVES: To investigate the in vitro antimicrobial properties and cytotoxicity of an experimental mouthrinse. METHODS: The mouthrinse contained 30% hexylene glycol (glycerine), 7% potassium nitrate and 0.025% sodium fluoride. The minimal inhibitory concentration (MIC) of these ingredients and the mixture was determined for C. albicans, S. aureus and S. mutans over 24 hours at different concentrations. The MICs of two commercial mouthrinses, Corsodyl and Plax, were also determined using the same organisms. All mouthrinses were then tested to determine the percentage kill over 1, 2, and 3 minutes. RESULTS: The MICs for hexylene glycol were 10%, 30% and 10% for C. albicans, S. aureus and S. mutons respectively. Potassium nitrate and sodium fluoride had no antimicrobial effects. The MIC of Corsodyl was 0.016 mg/ml for all the test organisms. The MIC for Plax varied from 0.0002 mg/ml to 0.001 mg/ml. The kill rates for all mouthrinses were acceptable, with no statistical differences between them. The experimental mouthrinse was not toxic to human oesophageal SCC cells after 1 minute exposure. At the time of the experiment, the costs of a similar quantity of the experimental mouthrinse, Corsodyl and Plax were R5.24, R30.00 and R10.00 respectively. CONCLUSIONS: The experimental mouthrinse was cost-effective and proved to have an antimicrobial effect and could be used safely to alleviate oral infections, desensitize teeth, improve oral hygiene and control dental caries in cancer patients after radiation therapy.

Disinfection of irreversible hydrocolloid impression material with chlorinated compounds.

PROBLEM: Irreversible hydrocolloid (alginate) impressions are dimensionally unstable and difficult to disinfect. PURPOSE: To evaluate the antimicrobial efficacy of a chlorite disinfectant (Presept) and a new formulation chlorine dioxide based disinfectant (Aseptrol) on irreversible hydrocolloid (alginate) impression material. MATERIALS AND METHODS: Alginate blocks were contaminated with Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus mutans and Bacillus subtilis spores. The blocks were placed either in sterile distilled water as control, or in 48-ppm Aseptrol or Presept solution containing organic matter. Immersion times were 30 seconds, 1, 1.5, 2, 3 and 5 minutes. The blocks were then placed in sterile 0.5% sodium thiosulphate neutralizer and surviving organisms were harvested and counted using the serial dilution technique followed by culturing on appropriate media. The anti-microbial efficacy of the solution was tested for 37 days. RESULTS: There was a consistent significant reduction (99.99%) in all tests of vegetative organisms after immersion in the Aseptrol for 30 seconds, and for spores after 1.5 minutes. It was effective against vegetative organisms for up to 27 days for a 30-second exposure. Presept significantly reduced (99.99%) C. albicans, S. aureus and S. mutans in 30 seconds, P. aeruginosa in 60 seconds, but for B. subtilis spores took at least 5 minutes. It was effective against vegetative organisms for >37 days for a 30-second exposure. CONCLUSION: Within the limits of this study it was found that both compounds effectively disinfected the alginate in the presence of organic material, but that Aseptrol did so after an immersion time of only 1.5 minutes. This immersion time is less likely to affect the dimensional properties of the impression material. CLINICAL IMPLICATIONS: The short action time of Aseptrol may make it ideal for the disinfection of alginate impressions, and it may also find many uses for disinfection and possible sterilisation.

Orthodontic treatment needs: comparison of two indices.

The Index of Orthodontic Treatment Needs (IOTN) and the Dental Aesthetic Index (DAI) were developed and both claimed to contain the aesthetic and dental components in their criteria of assessing malocclusion. This study was undertaken to assess the reliability of these two indices in assessing orthodontic treatment needs. The indices were applied to 120 pre-treatment study models selected from orthodontic patient records treated at the Department of Orthodontics, University of North Carolina, United States of America. The sample consisted of 60 African-Americans (Black) and 60 American Caucasians (White), age ranged from 12 to 16 years (Mean 13.8). The results showed that the IOTN and the DAI were highly correlated and highly associated statistically (p < 0.0001). The findings of this study indicated that the two indices could be used consistently to identify orthodontic treatment needs in different ethnic groups and are capable of classifying the subjects according to their malocclusion severity for those subjects eligible for treatment in fund constrained situation.

Determination and use of a transition state for the enzyme estrone sulfatase (ES) from a proposed reaction mechanism.

Using the postulated mechanism for the enzyme estrone sulfatase (ES), we have determined a possible transition state for the reaction catalysed by ES as a representation of the active site. Using the derived structure, we have undertaken the molecular modelling of several steroidal and non-steroidal inhibitors in an attempt to rationalise the inhibitory activity of a number of potent inhibitors.

Hydrophobicity, a physicochemical factor in the inhibition of the enzyme estrone sulfatase (ES).

We report the initial structure-activity relationship study (SAR) (in particular logP) of a series of compounds based upon 4-sulfamated phenyl ketones as potent inhibitors of the enzyme estrone sulfatase (ES). The results of the study show that these compounds are irreversible inhibitors of ES and that they are more potent than COUMATE, but weaker than EMATE. Analysis of the SAR data shows a strong correlation between IC(50) and logP but also supports our previous study, which suggests a very strong relationship between pK(a) and IC(50).

A comparison of the cost effectiveness of pressure-indicating materials and their ability to detect pressure areas in complete dentures.

Pressure areas on the fitting surfaces of dentures can cause great discomfort and pain to denture wearers if not detected and removed. Pressure-indicating materials are commonly used to detect these areas, and several commercial varieties are available, but these tend to be expensive. The cost effectiveness of these materials has not been investigated, nor has this been linked to their efficacy and ease of use. The aim of this study therefore, was to compare the different pressure-indicating materials available commercially with that of a home-made paste. An assumption of efficacy was made by the number and size of pressure areas revealed, by taking standardised photographs and analysing the images. User friendliness was determined by the time taken to mix, apply and remove the material. Cost was determined by a cost per unit calculation based on the average or minimum quantity required for each material. The results indicated that a home-made paste made of equal quantities of hand lanolin (BP) and zinc oxide powder was not only the most effective, but was also the cheapest, being only 3% of the cost of the most expensive of the materials.

Acid dissociation constant, a potential physicochemical factor in the inhibition of the enzyme estrone sulfatase (ES).

We report the initial results of the synthesis and biochemical evaluation of a series of aminosulfonate based compounds of phenol and the determination of the pKa of the parent phenol in an attempt to investigate the role of this physicochemical factor in the irreversible inhibition of the enzyme estrone sulfatase (ES). The results of the study show that there is a strong correlation between the observed pKa and inhibitory activity. We postulate that the stability of the phenoxide ion, as indicated by the acid dissociation constant, is an important factor in the irreversible inhibition of this enzyme.

Novel inhibitors of the enzyme estrone sulfatase (ES).

We report the initial results of our study into a series of simple 4-sulfamated phenyl alkyl ketones as potential inhibitors of the enzyme estrone sulfatase. The results of the study show that these compounds are potent inhibitors, possessing greater inhibitory activity than COUMATE, but weaker activity than EMATE. Furthermore, the compounds are observed to be irreversible inhibitors.

Inhibition of aromatase (P450Arom) by some 1-(benzofuran-2-ylmethyl)imidazoles.

Studies of a series of 1-(benzofuran-2-ylmethyl)imidazoles, 1-5, previously proposed as potential agents for prostatic cancer by their inhibition of 17beta-hydroxylase:17,20-lyase (P450 17), have been extended to their selectivity against placental microsomal aromatase (P450(Arom)) in man. The compounds were 3-7-fold more potent than aminoglutethimide and had some selectivity for P450 17 as expressed by the ratio (IC50 P450(Arom))/(IC50 P450) 17)/17.0 (2), 10.3 (3), 34.6 (4) and 42.0 (5), where IC50 is the concentration resulting in 50% inhibition. The lower potency of 1-5 towards P450(Arom) compared with the racemic alpha-phenyl-substituted compounds (6, 80-1000 x aminoglutethimide) and some racemic alpha-methyl (8.5 and 12.2 x aminoglutethimide) and alpha-ethyl (12.1 and 32.9 x aminoglutethimide) analogues has been rationalized. This work selectively extends studies of the P450 17 inhibitor 5, a potential prostatic cancer agent, towards other cytochrome P450 enzymes in the steroidogenic pathway and provides a general method for determining the relative influence of chemical manipulation of a parent inhibitor towards two enzymes in the pathway using additional literature data.

Some 1-[(benzofuran-2-yl)methyl]imidazoles as inhibitors of 17 alpha-hydroxylase: 17, 20-lyase (P450 17) and their specificity patterns.

Four 1-[(benzofuran-2-yl)methyl]imidazoles (1-4) have been evaluated as in-vitro inhibitors of human testicular and bovine adrenal microsomal 17 alpha-hydroxylase: 17,20-lyase (P450 17) as potential anti-prostatic agents. Their specificity towards other steroidogenic and liver enzymes has been compared with that of ketoconazole. All four compounds were inhibitors of the testicular enzyme (2, IC50 (concentration resulting in 50% inhibition) 0.185 microM; 4, IC50 0.18 microM) but less potent than ketoconazole (IC50 0.03 microM). Towards bovine adrenal enzyme 2 and 4 were 35- and 31-fold more potent than ketoconazole (IC50 = 39.8 microM). Compound 2 is a useful lead compound but although less potent than ketoconazole towards P450SCC and P450 11 beta, but not P450C21, at the enhanced dose required for equivalent effects in-vivo on P450 17 it is likely that cortisol and aldosterone production will be affected to a greater extent than with ketoconazole.