admission. This proportion could already be greater in some parts of the country and may increase if referrals of cases of self-poisoning increase faster than the facilities for their assessment and management. The provision of social work and psychiatric expertise in casualty departments may be one means of preventing unnecessary medical admissions without risk to the patients. Dr Blake's and Dr Bramble's figures do not demonstrate, however, that any advantage would attach to medical teams taking over assessment from psychiatrists except that, by implication, assessments would be completed sooner by staff working on the ward full time. What the figures actually suggest is that if assessment of overdoses were left to house doctors there would be an increase in admissions to psychiatric units (by 19°U), outpatients (by 5O°'), and referrals to social services (by 140o). So for house doctors to assess overdoses would provide no economy for the psychiatric or social services. The study does not tell us what the consequences would have been for the six patients who the psychiatrists would have admitted but to whom the house doctors would have offered outpatient appointments. E J SALTER

Vitamin D deficiency.

https://www.endoexperience.com/documents/PetersetalRotaryArticle.pdf

Current Challenges and Concepts in the Preparation of Root Canal Systems: A Review

http://www.biofilling.com/article/7_2Mineral.pdf

Mineral Trioxide Aggregate: A Comprehensive Literature Review—Part III: Clinical Applications, Drawbacks, and Mechanism of Action

Mineral trioxide aggregate: a comprehensive literature review--Part I: chemical, physical, and antibacterial properties.

Preparation of root canal systems includes both enlargement and shaping of the complex endodontic space together with its disinfection. A variety of instruments and techniques have been developed and described for this critical stage of root canal treatment. Although many reports on root canal preparation can be found in the literature, definitive scientific evidence on the quality and clinical appropriateness of different instruments and techniques remains elusive. To a large extent this is because of methodological problems, making comparisons among different investigations difficult if not impossible. The first section of this paper discusses the main problems with the methodology of research relating to root canal preparation while the remaining section critically reviews current endodontic instruments and shaping techniques.

Mechanical preparation of root canals: shaping goals, techniques and means

Burklein S, Hinschitza K, Dammaschke T, Schafer E. Shaping ability and cleaning effectiveness of two single-file systems in severely curved root canals of extracted teeth: Reciproc and WaveOne versus Mtwo and ProTaper. Interna- tional Endodontic Journal. Aim To compare shaping ability and cleaning effec- tiveness of two reciprocating single-file systems with Mtwo and ProTaper rotary instruments during the preparation of curved root canals in extracted teeth. Methodology A total of 80 root canals with curva- tures ranging between 25� and 39� were divided into four groups of 20 canals. Based on radiographs taken prior to instrumentation, the groups were balanced with respect to the angle and the radius of canal curvature. Canals were prepared to the following apical sizes: Mtwo: size 35 using the single-length technique; ProTaper: F3, instruments were used in a modified crown-down manner; Reciproc and WaveOne: size 25. Using pre- and post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. Preparation time and instrument failures were also recorded. These data were analysed statistically using anova and Student-Newman-Keuls test. The amounts of debris and smear layer were quantified on the basis of a numerical evaluation scale and were analysed statisti- cally using the Kruskal-Wallis test. Results During preparation no file fractured. All instruments maintained the original canal curvature well with no significant differences between the differ- ent files (P = 0.382). Instrumentation with Reciproc was significantly faster than with all other instruments (P 0.05), while ProTaper showed significantly more residual debris (P 0.05). Conclusions Under the conditions of this study, all instruments maintained the original canal curvature well and were safe to use. The use of Mtwo and Reciproc instruments resulted in better canal cleanli- ness in the apical part compared with ProTaper and WaveOne.

Shaping ability and cleaning effectiveness of two single-file systems in severely curved root canals of extracted teeth: Reciproc and WaveOne versus Mtwo and ProTaper.

Chemical and physical surface and bulk material characterization of white ProRoot MTA and two Portland cements.

https://hodsollhousedental.co.uk/wp-content/uploads/2014/01/Apical-extrusion-with-reciprocating-files.pdf

Apically Extruded Debris with Reciprocating Single-File and Full-sequence Rotary Instrumentation Systems

Chemical analysis and bonding reaction of RelyX Unicem and Bifix composites--a comparative study.

AIM The purpose of this study was to compare the shaping ability of FlexMaster rotary nickel-titanium instruments with stainless steel hand K-Flexofiles. This part of the two-part report describes the efficiency of these two instruments in simulated curved root canals. METHODOLOGY Simulated 28 degree- and 35 degree-curved canals were prepared by the FlexMaster instruments with a rotational speed of 250 rpm using a crown-down preparation technique. and by the K-Flexofiles using a reaming motion (n = 24 canals in each case). All canals were prepared up to size 35. The pre- and post-instrumentation images were recorded and assessment of the canal shape was completed with a computer image analysis program. The material removal was measured at 20 measuring points, beginning 1 mm away from the apex. Incidence of canal aberrations, preparation time,changes of working length and instrument failures were also recorded. RESULTS In comparison with stainless steel K-Flexofiles, the rotary FlexMaster instruments achieved bet-ter canal geometry, showed less canal transportation and created fewer canal aberrations in both the canal types. Two FlexMaster instruments were separated, and 15 FlexMaster instruments and 11 K-Flexofiles were permanently deformed during preparation. However, these differences were not significant (P > 0.05). Between both the canal types, FlexMaster was significantly faster (P < 0.001) than K-Flexofiles. Both instruments maintained a good working distance. CONCLUSIONS FlexMaster instruments prepared curved canals rapidly, and with minimal transportation towards the outer aspect of the curve.

Efficiency of rotary nickel-titanium FlexMaster instruments compared with stainless steel hand K-Flexofile--Part 1. Shaping ability in simulated curved canals.

Edgar Schäfer

Papers

Shaping ability and cleaning effectiveness of two single-file systems in severely curved root canals of extracted teeth: Reciproc and WaveOne versus Mtwo and ProTaper.

Chemical and physical surface and bulk material characterization of white ProRoot MTA and two Portland cements.

Apically Extruded Debris with Reciprocating Single-File and Full-sequence Rotary Instrumentation Systems

Chemical analysis and bonding reaction of RelyX Unicem and Bifix composites--a comparative study.

Efficiency of rotary nickel-titanium FlexMaster instruments compared with stainless steel hand K-Flexofile--Part 1. Shaping ability in simulated curved canals.