SEM Analysis of MTAD Efficacy for Smear Layer Removal from Periodontally Affected Root Surfaces.

OBJECTIVE: Biopure® MTAD (Dentsply Tulsa Dental, USA) has been developed as a final irrigant following root canal shaping to remove intracanal smear layer. Many of the unique properties of MTAD potentially transfer to the conditioning process of tooth roots during periodontal therapy. The aim of this ex vivo study was to evaluate the effect of MTAD on the removal of smear layer from root surfaces. MATERIALS AND METHODS: Thirty two longitudinally sectioned specimens from 16 freshly extracted teeth diagnosed with advanced periodontal disease were divided into four groups. In group 1 and 2, the root surfaces were scaled using Gracey curettes. In group 3 and 4, 0.5 mm of the root surface was removed using a fissure bur. The specimens in group 1 and 3 were then irrigated by normal saline. The specimens in groups 2 and 4 were irrigated with Biopure MTAD. All specimens were prepared for SEM and scored according to the presence of smear layer. RESULTS: MTAD significantly increased (P=0.001) the smear layer removal in both groups 2 and 4 compared to the associated control groups, in which only saline was used. CONCLUSION: MTAD increased the removal of the smear layer from periodontally affected root surfaces. Use of MTAD as a periodontal conditioner may be suggested.

The fundamental operating principles of electronic root canal length measurement devices.

It is generally accepted that root canal treatment procedures should be confined within the root canal system. To achieve this objective the canal terminus must be detected accurately during canal preparation and precise control of working length during the process must be maintained. Several techniques have been used for determining the apical canal terminus including electronic methods. However, the fundamental electronic operating principles and classification of the electronic devices used in this method are often unknown and a matter of controversy. The basic assumption with all electronic length measuring devices is that human tissues have certain characteristics that can be modelled by a combination of electrical components. Therefore, by measuring the electrical properties of the model, such as resistance and impedance, it should be possible to detect the canal terminus. The root canal system is surrounded by dentine and cementum that are insulators to electrical current. At the minor apical foramen, however, there is a small hole in which conductive materials within the canal space (tissue, fluid) are electrically connected to the periodontal ligament that is itself a conductor of electric current. Thus, dentine, along with tissue and fluid inside the canal, forms a resistor, the value of which depends on their dimensions, and their inherent resistivity. When an endodontic file penetrates inside the canal and approaches the minor apical foramen, the resistance between the endodontic file and the foramen decreases, because the effective length of the resistive material (dentine, tissue, fluid) decreases. As well as resistive properties, the structure of the tooth root has capacitive characteristics. Therefore, various electronic methods have been developed that use a variety of other principles to detect the canal terminus. Whilst the simplest devices measure resistance, other devices measure impedance using either high frequency, two frequencies, or multiple frequencies. In addition, some systems use low frequency oscillation and/or a voltage gradient method to detect the canal terminus. The aim of this review was to clarify the fundamental operating principles of the different types of electronic systems that claim to measure canal length.

A prospective satisfaction study and cost analysis of a pilot child telepsychiatry service in Newfoundland.

We evaluated user satisfaction with a PC-based videoconferencing system used for child psychiatry assessments and performed a cost analysis. Thirty patients (aged 5-16 years), accompanied by a parent, completed a psychiatric assessment using the videoconferencing system. One of five child psychiatrists was randomly assigned to each assessment. Satisfaction questionnaires were completed after each assessment by the psychiatrist, patient and parent. Parents also completed a cost questionnaire. The telecommunications bandwidth was 336 kbit/s. The psychiatrists stated that they were either 'very satisfied' or 'satisfied' with the telepsychiatry assessments. On a five-point Likert scale (1 = lowest, 5 = highest), 28 of the 30 parents (93%) rated their satisfaction level as 5; the other two rated it 4. All 30 parents (100%) stated that they 'liked' the telepsychiatry assessment and would use the system again. Twenty-nine parents (97%) indicated that they would prefer to use the telepsychiatry system to travelling to see a child psychiatrist in person. Eleven children (aged 5-12) participated and all (100%) said they 'liked' using the telepsychiatry system. Five out of nine children (56%) stated they liked the 'television doctor' better than the 'real' doctor; four said they had no preference. Nineteen adolescents (aged 13-16 years) participated and most were very satisfied or satisfied with the system. Seventeen of the 19 adolescents (89%) said they would prefer to see the psychiatrist on the videoconferencing system to travelling for an assessment, and the same number said that they would use telepsychiatry again. The estimated total travel cost for the 30 patients was $12,849, an average of $428 per patient. The total cost of the telepsychiatry service for the three-month pilot was $12,575, or $419 per patient.

Modified synthesis of 11-[14C]-clozapine.

The reported synthetic pathway of 8-chloro-11-(4-methyl-1-piperazinyl)-11-[14C]-5H-dibenzo[b,e][1,4]diazapine (clozapine) was modified in several steps. The synthetic pathway was shortened by 60% and the total yield was increased from 6% to 23%.

The Alder-Reilly anomaly in association with the myelodysplastic syndrome.

We describe the Alder-Reilly morphological abnormality in an elderly man with a myelodysplastic syndrome (MDS). The literature pertaining to abnormal neutrophil hypergranulation is reviewed and the possible role of myelodysplasia in its causation is discussed.

Effects of intravenous metoclopramide in 81 patients with tardive dyskinesia.

We compared acute effects of single intravenous administrations of metoclopramide (40 mg) and placebo in a double-blind crossover study involving 81 patients with tardive dyskinesia. Metoclopramide produced significantly greater reduction in mean total Abnormal Involuntary Movement Scale score as well as in ratings for six of the seven body areas, when compared with placebo. On adjusting each patient's metoclopramide response for his or her placebo response, we found that 35 of the 81 patients had 50% or greater placebo-corrected improvement. There were no apparent clinical differences between metoclopramide responders and nonresponders. Administration of 60 mg of metoclopramide to 15 patients produced greater improvement in tardive dyskinesia as compared with 40 mg; the incidence of acute dystonia, however, jumped from 10% with 40 mg to 33% with 60 mg.