In vitro dentine permeability: the relative effect of a dentine bonding agent on crown preparations.

Objective: The aim of this study was to determine whether a dentine bonding agent (DBA) had an effect in reducing fluid filtration under cemented provisional crowns.

Methods: Crown preparations on 34 premolars, randomly allocated to two equal-sized test and control groups, were assessed for dentine permeability by a fluid filtration technique. In the test group, prepared crowns were acid-etched and then treated with a DBA (Prime & Bond NT).

Effect of fluoride exposure on cariostatic potential of orthodontic bonding agents: an in vitro evaluation.

Aims: The aims of this in vitro study were to compare the cariostatic potential of a resin modified glass ionomer cement (Fuji Ortho LC) to that of a resin control (Transbond) for bracket bonding and to compare the effect of extrinsic fluoride application on the cariostatic potential of each material.

Setting: Ex vivo study.

Materials And Methods: Orthodontic brackets were bonded to 40 extracted premolars, 20 with Fuji Ortho LC and 20 with Transbond.

Fluoride release from orthodontic cements-effect of specimen surface area and depth.

Objective: The aims of this in vitro study were firstly to compare fluoride release from a disc model of two orthodontic cements with various surfaces varnished, reducing the surface area by 25, 50 and 75%; secondly, to measure the fluoride release from previously exhausted discs of the same cements following removal of various depths of surface material.

Methods: Forty discs of each cement, Fuji Ortho LC and Ultra Band-Lok, (6mm diameter by 3mm) were divided into two groups of 20 discs each. For each material, the first group was divided further into four groups of five discs, one group acting as control, while the other three groups were varnished reducing the surface area by 25, 50 and 75%, respectively.

Fluoride release from orthodontic band cements-a comparison of two in vitro models.

Objectives: To compare, in vitro, the fluoride release from a conventional glass ionomer cement (Ketac-Cem), a resin-modified glass ionomer cement (3M-Multicure) and a polyacid modified composite (Ultra Band-Lok) using a banded tooth model and a disc model with the same mean cement weight.

Methods: Forty pairs of caries-free third molars were collected and divided into two groups, each of 20 teeth. One tooth from each pair was banded with Ketac-Cem and the other with Ultra Band-Lok or 3M-Multicure; the average band size for each cement group was the same.

The pH and titratable acidity of a range of diluting drinks and their potential effect on dental erosion.

Objectives: To investigate, in vitro, the potential dental effects of diluting juices by measuring their acidity levels and to examine the effect dilution has on the potential erosive properties of the drinks.

Methods: Four commonly available diluting drinks were assessed for both pH and titratable acidity at a variety of dilutions, reflecting the range of concentrations over which such drinks may be consumed. Predetermined dilutions of citric acid and hydrochloric acid, with similar pH values to those of the drinks, were used as positive control acidic solutions.

The release of mercury from dental amalgam and potential neurotoxicological effects.

Objectives: The aim of this study was to estimate the amount of mercury released into both air and saliva from fresh and aged, abraded amalgam discs and then investigate neurotoxic effects of inorganic mercury upon sensory neuronal cultures.

Methods: An air-tight chamber was constructed to allow the combined estimation of mercury species released from amalgam pellets. The level released into air and saliva from both freshly packed and aged-abraded amalgam pellets was assessed.

Varnish or polymeric coating for the prevention of demineralization? An ex vivo study.

Objective: The ability of an experimental coating, Odyssey, to prevent demineralisation ex vivo was compared with that of a fluoride varnish, Duraphat and a chlorhexidine-containing varnish, Cervitec.

Design: an ex vivo single-blind study.

Setting: Hard tissue research laboratory.

Daily exposure to fluoride mouthrinse produces sustained fluoride release from orthodontic adhesives in vitro.

Objectives: To determine firstly, if sustained fluoride release can be achieved from five orthodontic adhesives: Ketac-Cem, Fuji ORTHO LC, Sequence, Transbond and Right-On, with daily exposure to fluoride mouthrinse in vitro, and secondly, if sustained fluoride release can be re-established from the same specimens, after an interruption in mouthrinse exposure.

Methods: Ten brackets were bonded to bovine incisors using each adhesive. Each adhesive group was divided equally into a test and a control sub-group.

Buffering capacities of soft drinks: the potential influence on dental erosion.

The pH of fruit juices and carbonated drinks are known to be low and have, therefore, been implicated in the increasing incidence of erosion. The ability of a drink to resist pH changes brought about by salivary buffering may play an important part in the erosion process. The aims of this study were to measure the initial pH of several widely available soft drinks and determine their buffering capacities.

Fluoride release, microbial inhibition and microleakage pattern of two orthodontic band cements.

Objectives: To compare, in vitro, the fluoride release, microbial inhibition and microleakage pattern of a conventional glass ionomer cement (Ketac-Cem) and an acid-modified composite (Ultra Band-Lok) for band cementation.

Methods: Fluoride release was measured from cement discs (3.0 mm diameter and 1.

Caries detector dyes--an in vitro assessment of some new compounds.

Previous studies have shown that the caries detector dyes, basic fuchsin and acid red, lack specificity. Accordingly, their clinical use can lead to the unnecessary removal of sound tissue. In the present study, the specificity of three further dyes, Carbolan Green, Coomassie Blue and Lissamine Blue was studied.

The effect of saliva on enamel and dentine erosion.

The present study aims to assess the ability of saliva, both in vitro and in situ, to prevent surface mineral loss from enamel and dentine when exposed to an erosive challenge. Fifteen groups of four varnished thin tooth sections were stored in saliva collected from individuals taking part in the in situ study and a further eight groups, each containing four sections, were stored in deionised water. In vitro, sections were stored in saliva or water for 14 days.

The effect of saliva on fluoride release by a glass-ionomer filling material.

The initial aim of this study was to investigate the effect of saliva and the formation of pellicle on the fluoride release in vitro of the glass-ionomer filling material, Chemfil Superior. For the first study glass-ionomer discs of 6 mm in diameter and 1.5 mm thick were made.

Fluoride release and cariostatic ability of a compomer and a resin-modified glass ionomer cement used for orthodontic bonding.

Objectives: The aims of this study were to compare the local and systemic uptake of fluoride released from a compomer material (Dyract Ortho) and a resin-modified glass ionomer cement (Vitremer) with that of a conventional resin adhesive (Right-On) and to compare the cariostatic ability of each of the test materials with that of the resin control.

Methods: Twenty six patients were randomly allocated to have a bracket bonded to a premolar on one side of the arch with one of the test materials and on the opposite side with the control material. Premolars destined for extraction as part of an orthodontic treatment plan were selected for bonding.

The effect of a resin-modified glass ionomer restorative material on artificially demineralised dentine caries in vitro.

Objectives: Recurrent caries is one of the most common reasons for the replacement of restorations. One method of reducing the frequency of this problem may be by using fluoride-releasing restorative materials. The aim of this in vitro study was to evaluate the progression of artificial lesions around resin-modified glass ionomer (Vitremer) restorations placed in root surfaces.

Application of transverse microradiography for measurement of mineral loss by acid erosion.

This paper describes a novel application of transverse microradiography for the detection and quantification of mineral loss due to acid erosion in thin tooth sections. Sixty-four specimens were randomly divided into eight equal-sized groups and exposed to an orthophosphoric-acid-based erosive fluid (pH = 3) for 0, 0.25, 0.

Determination of plaque pH changes within the trough of an in situ appliance used to study mineral changes in early carious lesions.

Plaque pH was measured using a glass combination pH microelectrode of plaque deposits lining the trough of an intra-oral appliance which contained single sections of human teeth with artificial enamel lesions. Plaque exposure to a 10% sucrose solution produced significantly lower plaque pH levels than a solution of sorbitol gum extract. The subsequent flow of saliva over the plaque/pH electrode interface resulted in a significant and rapid increase in pH.

Calcium ion diffusion from calcium hydroxide-containing materials in endodontically-treated teeth: an in vitro study.

The aim of this in vitro study was to determine the amount and duration of diffusion of calcium ions from both a calcium hydroxide-containing root canal sealer and an intracanal medicament, through the apical foramen and the dentinal tubules of endodontically-treated teeth. The root canals of 88 freshly extracted single-rooted teeth were prepared using the modified double flared, balanced force technique with patency filing. The teeth were divided into four test groups of 20 teeth each and a control group of eight teeth.

The effect of sucrose-containing chewing-gum use on in situ enamel lesion remineralization.

Two independent cross-over studies have now been carried out to evaluate the effect of a regime of chewing sucrose-containing gum on enamel lesion remineralization. The first study has been reported in detail elsewhere. This further study aimed to increase the data set with an additional 13 volunteers.

An evaluation of the effects of an Nd:YAG laser on subgingival calculus, dentine and cementum. An in vitro study.

The aim of this study was to evaluate the effects of Nd:YAG laser treatment on subgingival calculus, cementum and dentine, in vitro at different power settings and durations. The study included 2 experiments. In the 1st experiment, 32 extracted teeth with calculus were divided into 8 laser treatment groups.

The influence of fluoride-releasing bonding composites in the development of artificial white spot lesions. An ex vivo study.

This study investigates the effects of fluoride-releasing bonding composites on the development of artificially created white spot lesions ex vivo. The severity of the lesions was estimated visually using the von der Fehr Caries Index. The integrated mineral loss of the lesions (delta z) was measured using microradiography/microdensitometry.

An ex vivo investigation into the release of fluoride from fluoride-containing orthodontic bonding composites.

This study was concerned with an evaluation of fluoride release from commercially available orthodontic bonding composite resins, known as Reliance and Mirage Dual Cure, which are claimed to release ionic fluoride. Forty-eight premolar teeth had brackets bonded with four different composite resins--Mirage Dual Cure, Reliance, Right-on and Heliosit. They were then immersed in a demineralizing solution.

Fluoride uptake and release characteristics of glass ionomer cements.

The aims of this study were firstly to investigate the fluoride-releasing characteristics of five commercial glass ionomer materials: Ketac Fil, Chemfil Superior, Fuji II LC, Aquacem and Vitrebond. The second aim was to assess the fluoride uptake and subsequent release from the same range of materials. In both tests, ten discs, 6 mm in diameter with a thickness of 1.