Retention of posts with resin, glass ionomer and hybrid cements.

Objectives: To measure and compare the retention of serrated root canal posts cemented with glass ionomer, resin and resin-modified glass ionomer (hybrid) cements.

Methods: Fifty single-rooted human teeth were decoronated, treated endodontically and then embedded in resin blocks. Standard post-holes, 10 mm long, were prepared to receive 1.

Rigidity and retention of root canal posts.

Objective: To test the rigidity and the retention into roots of parallel root canal posts, one a spiral vented titanium post and the other a spiral serrated, hollow, stainless steel post. A serrated, stainless steel post was used as the control.

Materials And Methods: A three-point bending test was used to test rigidity.

Use of a pressure chamber to compare microleakage of three luting agents.

A pressure chamber was used to compare microleakage associated with complete metal crowns cemented to extracted teeth using three different luting agents. Complete crowns were cemented on 60 extracted premolar teeth: 20 were cemented using a zinc phosphate cement, 20 using a glass-ionomer cement, and 20 using a resin cement. Following 7 days of storage in normal saline, each of the teeth in the experimental groups was pressure cycled 15 times, during which time the occurrence of microleakage was monitored.

Effects of dental trauma on the pulp.

Infection of the root canal system following dental trauma induces pulp and periapical disease and prevents healing of previously healthy pulp. A clinical goal in treating trauma is the maintenance of pulp vitality, and clinicians should be aware of factors that influence pulp healing. The learning objective of this article is to review the factors and techniques that influence pulp vitality and examine the influence pulp has on the healing of adjacent tissues.

Bacterial penetration of the root canal of intact incisor teeth after a simulated traumatic injury.

One of the aims in treating traumatised teeth is to maintain the vitality of the pulp or allow conditions favourable for pulp revascularisation. However, infection of the pulp and root canal system may prevent this. A number of pathways have been proposed that allow bacteria to invade the root canal system, however most of these pathways cannot account for pulp infection in teeth that did not sustain injury to the periodontal attachment.

A scanning electron and confocal laser microscope investigation of tetracycline-affected human dentine.

Because of the well reported dental side-effects of tetracycline administration, the drug should not be administered to children. However, it and its derivatives are often administered over a prolonged period for treatment of acne in young adults. Dental side effects are also noticed in these patients.

The effect of serrations on carbon fibre posts-retention within the root canal, core retention, and post rigidity.

The retention in root canals of serrated carbon fibre Composiposts and stainless steel Paraposts was tested under tensile load. Twenty unrestored human roots were endodontically prepared and root filled. Two groups of 10 roots received 1.

Clinical management of infected root canal dentin.

Several hundred different species of bacteria are present in the human intraoral environment. Bacterial penetration of root canal dentin occurs when bacteria invade the root canal system. These bacteria may constitute a reservoir from which root canal reinfection may occur during or after endodontic treatment.

Rigidity and retention of carbon fibre versus stainless steel root canal posts.

Two of the main requirements of a root canal post are that it is rigid so as to resist flexing under functional load, and that it is well retained in the root. This study compared these properties in two different 1-mm diameter root canal posts--smooth carbon fibre posts (Endopost) and serrated stainless steel posts (Parapost). Ten posts of each type were tested for rigidity in a three-point bend test.

Adherence of Streptococcus gordonii to smeared and nonsmeared dentine.

The purpose of this study was to investigate the adherence of Streptococcus gordonii to smeared and nonsmeared dentine and to assess the influence of patent dentinal tubules on bacterial retention. In order to examine bacterial adherence, 10 non-smeared (group 1) and 10 smeared samples (group 2) of outer root dentine were prepared from teeth exhibiting dentine sclerosis. Ten non-smeared samples from inner coronal root dentine that did not exhibit sclerosis were prepared in order to study the influence of patent tubules on bacterial retention (group 3).

Penetration of smeared or nonsmeared dentine by Streptococcus gordonii.

The purpose of this study was to investigate the penetration of smeared and nonsmeared dentine by Streptococcus gordonii. Prepared human roots, grouped as either nonsmeared or smeared, were immersed in a suspension of S. gordonii cells for 3 weeks.

Increases in cavity volume associated with the removal of class 2 amalgam and composite restorations.

Removal of amalgam restorations from class 2 cavities has been shown to cause increases in cavity volume. The aim of this study was to test whether the removal of composite resin from class 2 cavities was associated with greater increases in cavity volume compared to that produced during removal of amalgam. Class 2 cavities were prepared in previously extracted human molar teeth and the cavity volumes calculated.

Simulation models for teaching endodontic surgical procedures.

Models which simulate oral conditions pertaining to endodontic surgical procedures are most suitable if they contain natural teeth and have hard and soft tissues which handle realistically. In addition, the model should possess radiological characteristics similar to bone. A simple custom-built model which fulfils these requirements is described.

Impact fracture characteristics of intact and crowned human central incisors.

Dynamic fracture energies and patterns of fracture in extracted human central incisors were determined for groups of intact controls, groups with Vita Dur N crowns, Vita Hi Ceram crowns, Dicor crowns and porcelain veneers. Teeth were struck on their middle labial surfaces by a pendulum impact device. The mean fracture energy for teeth with Dicor crowns was significantly lower than for all other groups (P < 0.

Effectiveness of sterilisation and disinfection procedures for dental amalgam carriers.

The potential for cross infection through dental amalgam carriers was investigated in 37 Dunedin dental practices and in the University of Otago School of Dentistry. Eighteen practitioners had autoclavable carriers, but only 2 autoclaved them at least daily. The School of Dentistry disinfected plastic carriers and autoclaved metal carriers.

A cost-effective method for producing custom dental teaching aids using RTV silicone.

A method for making low-cost custom dental teaching aids, using components of standard models and a silicone replication technique, is described. The process is quick, and is suitable for both small and large numbers of individual model types.

Artificial caries around restorations in roots.

An artificial caries technique was used to produce caries-like lesions in the cavity walls adjacent to microfilled resin restorations with and without dentin bonding agent, and glass-ionomer cement restorations, in the roots of extracted teeth. The lesions had histological characteristics similar to those of natural lesions and to those of the lesions produced by other experimental methods. The zonal pattern of the lesions was examined by means of polarized light microscopy and microradiography, and the depth of the lesions was measured for assessment of the microleakage around the restorations.