No abstract

It is proposed that the approach employed to use a combination of measurement and analytical techniques to quantify the wear facet volume (profilometry), wear trough (SEM) and material transfer (EDS) provides more useful information on the wear mechanism and the tribology of the system rather than relying on a simple wear ranking for the RBC materials as is routinely the case in dental research studies.

SUMMARY Objective: This study aimed to evaluate the irradiance and the quality of LED light curing units (LCUs) in primary and secondary clinics in the UK and to assess the effect of damage, contamination, use of protective sleeves, and distance of light tips to target on the irradiance and performance of LCUs. Methods: The irradiance levels (mW/cm2) of 26 LED LCUs from general dental practices and 207 LED LCUs from two dental hospitals were measured using a digital radiometer (Blue Phase II, Ivoclar, Vivadent, Amherst, NY). Ten LED light guide tips (Satelec Mini, Acteon, Merignac, France) were selected to evaluate the effect of chipping, contamination (tip debris), and use of protective sleeves and tips to sensor distance on irradiance (mW/cm2) using a MARC Resin Calibrator (Blue Light Analytics, Halifax, Canada). Homogeneity of the light output was evaluated using a laser beam profiler (SP620; Ophir-Spiricon, North Longan, UT, USA). Statistical analysis was conducted using a one-way analysis of variance (ANOVA) with post hoc Tukey test (α=0.05) and linear regression with stepwise correlation tests. Results: Thirty-three percent of the LCUs delivered irradiance output less than 500 mW/cm2. The condition of the light curing tips was poor, with 16% contaminated with resin debris, 26% damaged, and 10% both contaminated and damaged. The irradiance output was significantly reduced in contaminated (62%) and chipped (50%) light curing tips and when using protective sleeves (24%) (p<0.05). Irradiance was also reduced when increasing the distance with 25% and 34% reduction at 7 mm and 10 mm, respectively (p<0.05). Conclusion: There remains a lack of awareness of the need for regular monitoring and maintenance of dental LCUs. Damaged and contaminated light curing tips, use of protective sleeves, and increasing the distance from the restoration significantly reduced the irradiance output and the performance of the LCUs.

The first part of this series on the conventional rehabilitation of oncology patients with hard palate defects discussed the dental challenges posed by oncology patients and the surgical/restorative planning interface for conventional dental rehabilitation. This article will describe Aramany's classification of hard palate defects, Brown's classification of palatal defects and focus on the basic principles of obturator design which need to be appreciated when prosthetically rehabilitating a patient with a hard palate defect. Clinical relevance statementA good understanding of basic removable prosthodontic theory relating to denture design, dental materials science and head and neck anatomy is an absolute prerequisite when designing an obturator for a patient. Learning ObjectiveThis article will describe: (a) how hard palate defects can be classified and (b) the basic principles of obturator design which need to be appreciated when rehabilitating a patient with a maxillectomy defect.

This is a repository copy of Development and characterisation of dental composites containing anisotropic fluorapatite bundles and rods.