Biomedical subjects
Publications and source records attributed to Philip J Lumley.
Root canal therapy is not always successful and an increasing number of patients are requesting retreatment to address intraradicular infection. The armamentarium available to assist the dentist, some of which is described in this article, has never been greater.
A postal survey of recent United Kingdom dental graduates was undertaken to establish the amount of their undergraduate endodontic experience and their opinions of their training. A 75% response was achieved from all but two schools. Recent graduates had generally undertaken fewer cases as students than older graduates. Several had undertaken very few endodontic procedures as students. Differences and trends were seen in the opinions of students and their experiences among the schools, and between the two year groups studied. Most students were not very confident to undertake molar endodontics. Many felt they needed more practical experience as students and training in newer techniques and instrumentation.
This is the first in a series of four papers aimed at understanding human pulpal responses to tissue injury, cavity preparation and restorative events. This article provides an insight into the exquisite regenerative potential of the dentine-pulp complex which underpins the success of restorative dentistry.
The exciting treatment possibilities arising from tissue engineering approaches are still some years away from involvement in dentistry. Meanwhile, it is important to optimize conventional treatments, although precise information on pulp responses to cavity preparation and restoration variables are limited. Odontoblast survival, pulp inflammation, and tertiary dentine area are used as measures of pulp injury and repair.
Confusion surrounds the pivotal role played by the remaining dentine thickness in a cavity in determining pulpal injury and repair response outcomes after restorative treatment. The multifactorial nature of the injury repair response requires that attention is focused on the most important factors, including remaining dentine thickness, to harness the natural regenerative properties of the pulp and to avoid postoperative treatment complications.
The sequence of factors that mediate pulp inflammation and necrosis are unclear, and controversy surrounds the effects of different pulp capping materials on exposed pulps. Clinicians have few quantitative studies that rank the in vivo pulp capping effects of commonly used restorative materials.
PURPOSE: To investigate pulpal injury by measuring odontoblast numbers, and pulp dentin repair activity by measuring reactionary dentin area, in relation to the remaining dentin thickness (RDT) of cavity preparations in 217 human teeth. MATERIALS AND METHODS: Cavities were restored with adhesive bonded composite, resin-modified glass-ionomer cement, zinc oxide-eugenol or calcium hydroxide materials. The teeth were extracted for orthodontic reasons between 20-381 days post-operatively, and odontoblast numbers and reactionary dentin area were analyzed histomorphometrically, and statistically using ANOVA. RESULTS: Reactionary dentin deposition was observed beneath cavities with a RDT above 0.5 mm as well as beneath cavities with a RDT below 0.25 mm; however maximal reactionary dentin appeared to be beneath cavities with an a RDT between 0.5-0.25 mm (P= 0.0001). The area of reactionary repair was also influenced by the choice of restoration material (P= 0.0385) from greatest to least; calcium hydroxide, composite, resin-modified glass-ionomer cement and zinc oxide-eugenol. Odontoblast numbers were maintained beneath cavities with a RDT above 0.25 mm, cavities placed closer to the pulp appeared to injure underlying odontoblasts, reducing their numbers (P= 0.0001). The choice of cavity restoration material also influenced the survival of underlying odontoblasts (P= 0.0061).