A controlled clinical trial of a therapeutic bacteriophage preparation in chronic otitis due to antibiotic-resistant Pseudomonas aeruginosa; a preliminary report of efficacy.

OBJECTIVES: To evaluate the efficacy and safety of a therapeutic bacteriophage preparation (Biophage-PA) targeting antibiotic-resistant Pseudomonas aeruginosa in chronic otitis. DESIGN: Randomised, double-blind, placebo-controlled Phase I/II clinical trial approved by UK Medicines and Healthcare products Regulatory Agency (MHRA) and the Central Office for Research Ethics Committees (COREC) ethical review process. SETTING: A single specialist university hospital. PARTICIPANTS: 24 patients with chronic otitis with a duration of several years (2-58). Each patient had, at the time of entry to the trial, an ear infection because of an antibiotic-resistant P. aeruginosa strain sensitive to one or more of the six phages present in Biophage-PA. Participants were randomised in two groups of 12 treated with either a single dose of Biophage-PA or placebo and followed up at 7, 21 and 42 days after treatment by the same otologist. Ears were thoroughly cleaned on each occasion and clinical and microbiological indicators measured. MAIN OUTCOME MEASURES: Physician assessed erythema/inflammation, ulceration/granulation/polyps, discharge quantity, discharge type and odour using a Visual Analogue Scale (VAS). Patients reported discomfort, itchiness, wetness and smell also using a VAS. Bacterial levels of P. aeruginosa and phage counts from swabs were measured initially and at follow-up. At each visit patients were asked about side effects using a structured form. Digital otoscopic images were obtained on days 0 and 42 for illustrative purposes only. RESULTS: Relative to day 0, pooled patient- and physician-reported clinical indicators improved for the phage treated group relative to the placebo group. Variation from baseline levels was statistically significant for combined data from all clinic days only for the phage treated group. Variation from baseline levels was statistically significant for the majority of the patient assessed clinical indicators only for the phage treated group. P. aeruginosa counts were significantly lower only in the phage treated group. No treatment related adverse event was reported. CONCLUSION: The first controlled clinical trial of a therapeutic bacteriophage preparation showed efficacy and safety in chronic otitis because of chemo-resistant P. aeruginosa.

Ridge contour related to esthetics and function.

Maxillary anterior fixed prostheses may be compromised when pontics are adapted to deficient residual alveolar ridges. This study determined the effect of ridge contour on esthetics and function. Thirteen men and 17 women, 23 to 75 years of age, who had received maxillary anterior fixed prostheses during the period 1976 to 1986 participated. A six-item structured interview was conducted for each subject to determine causes of satisfaction or dissatisfaction with esthetics and function. Pontic esthetics were also determined by examination using a 12-point esthetic index that was developed and pretested for this study. Residual ridge contour was classified according to Siebert as being deficient buccolingually (I), deficient apicocoronally (II), or deficient in both areas in combination (III). The results showed that patients with class I ridges had a higher subjective level of satisfaction with their prosthesis than did those with class II or III ridges. Esthetic index scores were significantly higher (p less than 0.05) for type I (10) than for type II (7.4) or III (7.3) using a post hoc Scheffé comparison. These results suggest that consideration be given to ridge augmentation prior to construction of maxillary anterior fixed prostheses, particularly when class II or III defects are present.

Optimal citric acid concentration for dentinal demineralization.

A number of acids have been shown to have a peak concentration above which the rate of enamel demineralization diminishes. Citric acid, used to demineralize dentin in periodontal regenerative procedures, is one such acid. The purpose of this study was to ascertain if there were an optimal concentration of citric acid with which to demineralize dentin. Various concentrations of citric acid were applied to bovine dentin and then examined with atomic absorption spectrophotometry to measure the amount of calcium dissolved in each concentration. The ppm calcium/% citric acid solution rose from 0.38 +/- 0.38 ppm/0% (control) to a peak of 7.54 +/- 2.26 ppm/24%, then fell to 2.43 +/- 0.59 ppm/80%, suggesting that there may be a peak concentration beyond which effective dentinal demineralization diminishes. The peak solution was pH = 1.42.

Dental students' perceptions of the difficulty of faculty positions.

How undergraduate dental students at Dalhousie University perceive various aspects of the positions held by faculty members was determined by responses on a 20-item questionnaire. Comparisons of item responses by students' class year, age group, marital status, sex, and perceived class standing generally produced a similar rank order of questionnaire items. Students perceived faculty positions that involved a high degree of administrative responsibility as being more difficult than preclinical instruction and part-time faculty positions. Research was perceived by students to be of low importance to faculty. It is important to consider the various perceptions that students hold regarding faculty positions if changes are planned to improve the teaching environment. A wide divergence between the perception held by faculty and students regarding the difficulties of a faculty position may hinder optimum student-faculty relationships.