Comparison of different methods for the diagnosis of fissure caries without cavitation

The aim of this study was to compare the accuracy of several common methods for the diagnosis of fissure caries. 63 human teeth without fillings and without any macroscopic carious cavitation but with different degrees of fissure discoloration and decalcification were selected from a pool. Dentists were asked to examine embedded teeth for fissure caries. The examination was done under standard conditions in a professional dental unit. The methods employed were: visual inspection (VI, n = 26 dentists), visual inspection with a magnifying glass (2x; VIM; n = 26), conventional bite-wing radiography (BW; n = 24), visual inspection combined with conventional bite-wing radiography (VI + BW; n = 10), and visual inspection combined with light pressure probing (VI + P; n = 23 dentists). In order to measure the reproducibility, VI and VI + BW were repeated. After the last inspection, the teeth were histologically prepared, serially sectioned perpendicular to the occlusal surface, and diagnosed for the presence of caries. The agreement between histological and clinical diagnosis was assessed. Specificities and sensitivities were: VI = 93 and 12%, VIM = 89 and 20%, BW = 83 and 45%, VI + BW = 87 and 49%, and VI + P = 93 and 14%, respectively. The following likelihood ratios were found: VI = 1.84, VIM = 1.86, BW = 2.6, VI + BW = 3.85, and VI + P = 2.05. It was concluded that the rather low sensitivity especially for VI and VI + P may lead to a significant number of teeth with dentinal caries being undetected.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of different factors on in vitro enamel erosion

The aim of this study was to use two demineralization test methods to analyze the erosive potential of beverages and foodstuffs. In addition, the surface microhardness test and the iodide permeability test were compared. Surface microhardness and iodide permeability were measured before and after exposure. To characterize the beverages and foodstuffs the content of phosphate, calcium and fluoride, pH, the titrable amount of base to pH 5.5 and 7.0 as well as the buffer capacity at pH 5.5 were determined. Sprite light showed the highest significant decrease in surface microhardness (p < or = 0.05) followed by grapefruit juice, apple juice and salad dressing. The highest significant increase in iodide permeability (p < or = 0.05) was caused by exposure to grapefruit juice followed by apple juice (Sprite light was not tested). Multiple linear regression analyses revealed that the erosive capacity of different drinks, juices and foodstuffs are statistically significantly associated with their acidity, pH values, phosphate and fluoride contents as well as the baseline surface microhardness or iodide permeability values of the exposed enamel.

Effectiveness of three cavity varnishes in reducing marginal microleakage of amalgam restorations: an in vitro study

Dentin Adhesit, Cavi-Line and Kavite Lak cavity varnishes were applied to the walls of prepared Class V cavities in fifty-two caries free extracted molar teeth before placing amalgam fillings. Tests with Methylene Blue dye after thermocycling showed that all cavity varnishes showed significantly lesser marginal leakage when compared with the control group without any cavity varnish.

Dental erosion in a population of Swiss adults

The purpose of this study was to determine the prevalence of dental erosion in an adult population in Switzerland. 391 randomly selected persons from two age groups (26-30 and 46-50 yr) were examined for frequency and severity of erosion on all tooth surfaces. Information was gathered by interview about lifestyle, dietary and oral health habits. For facial surfaces 7.7% of the younger age group and 13.2% of the older age group showed at least one tooth affected with erosion with involvement of dentin (grade 2). 3.5 teeth per person in the younger and 2.8 teeth per person in the older age group were affected. Occlusally, at least one severe erosion was observed in 29.9% of the younger and 42.6% of the older sample with 3.2 and 3.9 erosion-affected teeth per person, respectively. 3.6% of the younger age group and 6.1% of the older age group showed slight lingual erosion on the maxillary anterior teeth. Severe lingual erosions were scarce. Data from interviews and multiple regression analyses revealed that acids from beverages are significantly associated with presence of erosion.

Comparison of the sealing ability of four cavity varnishes: an in vitro study

The purpose of this study was to test and to compare, in vitro, the sealing ability of four different cavity varnishes used to minimize the marginal leakage of amalgam fillings. For this purpose, a model was developed in order to avoid quality-deteriorating effects (such as condensation forces used during placement of amalgam) and temperature changes. In this model, raw ceramic disks were used instead of dentin. The four varnishes showed significant reducing effect on the penetration of the dye (Methylene Blue) compared with the control. There was no cavity varnish with optimal sealing.

Validity of diagnostic and treatment decisions of fissure caries

The purpose of this in vitro study was to test the accuracy and the reproducibility of diagnostic and treatment decisions of fissure caries with and without explorer. 34 dentists were asked to diagnose 61 teeth and decide upon possible treatment. The teeth were then histologically prepared and diagnosed. The agreement between histological and clinical diagnoses was assessed. The results showed no difference in diagnostic accuracy between explorer and visual technique only. Sensitivity (62%) and specificity (84%) showed that the dentists were more likely not to treat decayed teeth than to restore sound teeth. The percentage 'correctly diagnosed teeth' was approximately 42%. As there was an inherent possibility of a correct diagnosis by chance, this value had to be corrected to 23% (kappa statistics). The percentage of 'clinically' correct treatment decisions, however, was 73%. The reproducibility test gave kappa values of 0.47 for diagnostic and 0.44 for treatment decisions. It was concluded that the use of an explorer does not improve the validity of the diagnosis of fissure caries when compared to that of a visual inspection alone.

Mercury and copper release from amalgams in different soft drinks

Release of mercury and copper over time from three different non-gamma-2 amalgams in a polished and unpolished state was tested in water and two soft drinks. The measuring methodology was geared to warrant minimum Hg losses due to evaporation and adsorption. Initial (24 h) values for Hg and Cu were relatively high in water, but were much lower in the soft drinks. The 24-104-hour values were much lower than the initial readings for all amalgams and all environments. Polishing reduced leaching--significantly, however, only in water and for only two of the three amalgams. The lower values in the soft drinks and over time could be due to passivation of the amalgam. Passivation appears to be time-dependent and chemically influenced by the environment.

Mineral induction by immobilized polyanionic proteins

The purpose of this study was to investigate the mineral induction capacity in vitro of polyanionic proteins covalently bound to a surface. Rat dentin gamma-carboxyglutamate-containing protein of the osteocalcin type (Gla-protein), proteoglycan (PG), and phosphoprotein (PP-H), as well as phosvitin (PhV) and bovine serum albumin (BSA), were covalently linked to agarose beads. There were incubated at 37 degrees C in solutions with a Ca/P molar ratio of 1.67, [Ca][P] molar products in the range 1.0-1.8 mM2, and an ionic strength of 0.165. The incubations were performed at constant pH and composition conditions; no spontaneous precipitation occurred under these conditions. Mineral formation, as monitored by scanning electron microscopy (SEM), was induced by all immobilized polyanions, including enzymatically dephosphorylated PP-H and PhV. No mineral was induced by BSA. The mineral inductive capacity of immobilized polyanionic proteins, as judged by the SEM after identical incubations, was found to differ between the different ligands. The mineral induced by PP-H and PG was shown by X-ray diffraction to be apatitic. It was concluded that, although polyanionic proteins in solution may inhibit mineral induction and growth, very minute quantities of such molecules, when immobilized on a surface, induce mineral at physiological concentrations of calcium and phosphate ions. The data presented may be taken to suggest that PP-H and PG, and perhaps other polyanions, may possibly be responsible for mineral nucleation in dentin and bone. The results, however, also point to the rather limited specificity in this type of reaction.

Mineral induction by polyanionic dentin and bone proteins at physiological ionic conditions

Polyanionic proteins of calcified tissues have been postulated to provide calcium ion-binding sites which initiate mineral formation, even though it is known that such proteins in solution may inhibit apatite induction and growth. In the studies reviewed here, it was shown that minute amounts of non-collagenous macromolecules from dentin and bone, such as phosphoprotein and proteoglycan, are capable to induce apatite at physiological ion concentrations in vitro, when immobilized on a stable support.

A new method for finishing minicavities

Minicavities were prepared in 26 caries-free teeth. Cavity preparation and the finishing of the occlusal area and the gingival floor was done with diamond burs (diameter 1 mm, grain sizes 90 micron and 15 micron, respectively). For the finishing of the axial box margin and the proximo-cervical curved border, a new set was developed: It is composed of an EVA-system with the total amplitude reduced to 0.34 mm, and a highly flexible file (Cavishape, grain 15 micron). The shape of this file had to be modified in order to follow the proximo-cervical curvature. The efficiency of the new device was compared with the axial margin trimmer by means of scanning electron microscopy and a score system. The new device allowed a significantly better finishing of the proximo-cervical curvature and of the axial box margin.

The in vitro uptake of fluoride by secretory and maturation stage bovine enamel

The objectives of this study were to determine the specific surface area of secretory-stage and of maturation-stage enamel, to compare the fluoride uptake by isolated enamel at these two stages on a surface-area basis, and to examine the effect of the organic matrix on the fluoride uptake by whole enamel. Fetal bovine secretory and maturation stage enamel samples were collected, and a portion of the enamel at each developmental stage was treated with hydrazine for removal of the organic matrix. The specific surface areas of the enamel mineral, as determined by the multi-point BET method, were 59.3 m2/g in the secretory stage and 37.9 m2/g in the maturation stage. Whole and deproteinated enamel samples were equilibrated in buffered solutions containing 10(-5) to 10(-3) mol/L fluoride, and the uptake was measured with a fluoride specific electrode. The results indicate that the in vitro fluoride uptake was controlled solely by the surface area of the apatitic mineral and that the organic matrix did not contribute to the fluoride uptake.

Induction and inhibition of hydroxyapatite formation by rat dentine phosphoprotein in vitro

Highly phosphorylated rat incisor phosphoprotein (PP-H) was purified and covalently attached to agarose beads. The beads were incubated for 24 h in solutions having an ionic strength of 0.165, a molar Ca/P ratio of 1.67, and a pH of 7.4. The calcium-phosphate concentration products [( Ca][P]) in the stable incubation solutions ranged from 1.0 to 1.8 mM2, from which no spontaneous precipitation occurred. In a timed series mineral formation was monitored by SEM and X-ray diffraction. The inhibitory capacity of PP-H, free solution, was also studied. The first mineral appeared after 10 min at a [Ca][P] product as low as 1.2 mM2; X-ray diffraction showed that the mineral was (hydroxy)apatite. Thus small amounts of PP-H attached to a surface are capable of inducing mineral formation in vitro at comparatively low supersaturation, whereas PP-H is a mineral inhibitor when free in solution.

Absence of in-vitro fluoride-binding by the organic matrix of developing bovine enamel

The in-vitro binding of fluoride to isolated organic matrix of secretory bovine enamel was studied by direct fluoride measurement and equilibrium dialysis. Over a wide range of protein and fluoride concentrations there was no indication of fluoride binding by the matrix in contrast to earlier reports.