The sealing ability of an epoxy resin root canal sealer used with five gutta-percha obturation techniques

The purpose of the present study was to evaluate the apical sealing ability of an epoxy resin root canal sealer (AH-26) when used with different gutta-percha obturation techniques (i.e. cold lateral condensation, warm vertical condensation, hybrid condensation) and with Thermafil and Soft-Core obturators. Straight single-rooted teeth with mature apices were prepared according to the crown-down/step-back technique and divided in five groups of 45 teeth and one group of 12 control teeth. After root canal filling 15 teeth of each group were kept for 1 day, another 15 teeth for 1 week, and another 15 teeth for 4 months at 37 degrees C in vacutainers in 80% relative humidity. The 237 teeth were immersed in india ink for 90 hours, each root was split and sectioned longitudinally, and the maximum extent of leakage was measured using a stereomicroscope at x6 magnification. It became clear that leakage occurred whatever technique was combined with AH26 and that leakage increased with time. The amount of apical leakage and the number of leaking teeth in the Soft-Core obturator groups was significantly higher than all other 4 gutta-percha obturation techniques combined with AH26. In this respect, the hybrid gutta-percha condensation technique turned out to be superior to the four other condensation techniques.

Tongue piercing and associated oral and dental complications

The insertion of metal objects into intraoral and perioral sites is growing in popularity. However, there are numerous oral and dental complications associated with tongue piercing. Fifteen patients with tongue piercings (pierced in the body of the tongue, anterior to the lingual frenum) attending the dental office of the authors, with and without complaints, were clinically and radiographically examined. The most common dental problem registered was chipping of teeth. Furthermore, two cracked teeth and four teeth with cusp fractures were also seen. One case of selective dental abrasion was registered. Trauma to the lingual anterior gingiva was the most common gingival problem. A salivary flow stimulating effect was only reported by 2 of the 15 individuals. None of the patients complained of interference with speech, mastication and swallowing. One case of galvanic currents produced by the appliance was registered. On the basis of the registered data, we concluded that patients need to be better informed of the potential complications associated with tongue and oral piercings, and that the dental profession can serve this role.

Periapical health related to the quality of root canal treatment in a Belgian population

AIM

The aim of this study was to collect data on the prevalence and technical standard of root canal treatment as well as the prevalence of apical periodontitis in Belgium.

METHODOLOGY

The panoramic radiographs of 206 Belgian adults attending the Dental School of the University Hospital of Gent were examined for endodontic treatment, periapical conditions and coronal restorations.

RESULTS

Of the 4617 teeth examined, 6.8% were endodontically treated. Periapical radiolucencies were found in 6.6% of all teeth and in 40.4% of the endodontically treated teeth. More than half of the root-filled teeth (56.7%) were scored inadequate on the basis of a criterion evaluating the level of the root canal filling.

CONCLUSION

The endodontic treatment need of this Belgian subpopulation was great and the technical standard of root canal treatment disappointing. The findings indicate that there is still a substantial need for postgraduate endodontic education in Belgium and a need for specialists in endodontology.

Necrosis of the gingiva caused by calcium hydroxide: a case report

CASE REPORT

The present case demonstrates the possible detrimental effect of an overextension of a calcium hydroxide intracanal dressing into the periradicular and soft tissue after iatrogenic buccal root perforation of a maxillary central incisor. At first this perforation was not recognized by the dentist, which resulted in the introduction of a large amount of non-setting calcium hydroxide paste under the gingival tissues through a dehiscence on the buccal side of the root. This report describes the consequences and management of the necrosis of the buccal gingiva and mucosa, and the subsequent treatment and follow-up of the root perforation.

Apical microleakage after lateral condensation, hybrid gutta-percha condensation and Soft-Core obturation: an in vitro evaluation

The purpose of the present study was to evaluate the apical seal of root canals filled with a cold lateral condensation, a hybrid gutta-percha condensation technique and with Soft-Core obturators. Three groups of 35 maxillary anterior teeth and four control anterior teeth were treated with a crown-down/step-back technique. All roots were submerged in India ink for 1 week. The roots were cleared and the degree of linear dye penetration was measured. The mean apical leakage for the Soft-Core technique was at least twice as extensive as for the two other gutta-percha obturation techniques. No statistically significant differences were found between the two other condensation techniques.

Accuracy of four electronic apex locators: an in vitro evaluation

In the present study, the accuracy and operator dependency of four electronic canal length measuring devices (Apex Finder AFA Model 7005, Apex-Finder, Neosono Ultima EZ and Apit 2) were compared under a set of specified conditions. The electronic apex locators were tested in unflared dry, flared wet and flared dry canals, and in a gelatin as well as in a sodium hypochlorite sponge model. Fifteen extracted single-canaled teeth were selected. The differences between canal lengths obtained by the electronic apex locators and actual canal lengths were scored. Only the Apex-Finder was found to be unreliable (measurements higher than +/- 0.5 mm from the apical foramen). This device was also found to be particularly dependent on operator. A ranking based on a precision of +/- 0.1 mm from the apical foramen showed the Apex Finder AFA Model 7005 to be the most accurate. Early coronal flaring did not ensure better or more precise readings. The gelatin model was evaluated to be more suitable for testing electronic apex locators in vitro than the sodium hypochlorite model.

Changes in surface hardness of conventional restorative glass ionomer cements

The effect of a contact with an aqueous solution on the surface hardness of glass ionomers has been investigated in a few studies and for a limited number of formulations. As there is no information on the long-term changes of the surface hardness in this respect, the aim of this study was to determine these long-term changes in 10 conventionally setting glass ionomer formulations after storage in water as compared to maturation in a humid atmosphere (85% RH). After setting for 15 min different series of glass ionomer specimens were stored at 37 degrees C in both experimental media for 1, 7, 28 and 140 days. At the end of the specific maturation times, the mean surface hardness was determined on the basis of Knoop Hardness (KHN). Data were analyzed using ANOVA. In a humid atmosphere the surface hardness generally increases rapidly initially, followed after 1 day by a more gradual increase. In contact with water, the hardness also increases up to one day but not to the same extent. The surface hardness then remains constant or slightly decreases. Evidence of a detrimental softening of the surface ascribed previously to the loss of matrix forming ions was not found. A surface erosion is not likely to occur.

Effect of acetic acid on the fluoride release profiles of restorative glass ionomer cements

OBJECTIVES

This study investigates the fluoride release of glass ionomers in an acetic acid solution in order to substantiate a model according to which the short-term release results from an elution of loosely bound fluoride and the long-term release from an erosive leaching of the glass particles in the bulk of the cement.

METHODS

Individual fluoride release profiles of five specimens of 10 acid-base setting restorative glass ionomers were obtained by determining the amounts of fluoride released by each sample at 37 degrees C in consecutive elutions for up to 140 days with 25 ml of a 0.01 mol/l acetic acid solution with pH = 4. Differences in the fluoride release profiles were determined with a Multivariate Data Analysis on the basis of a Principal Component Analysis.

RESULTS

The fluoride release profiles of the 10 glass ionomers can be classified into five distinct groups which are characterized by a cumulative fluoride release described by the equation [F]c = [F]l t/(t + t1/2) + beta square root of t. The parameters ([F]l, t1/2) and beta are characteristic for the materials in the groups, and refer to the short-term and long-term fluoride release, respectively. The acidic solution enhances both processes compared to an elution in water, the effect being more pronounced for the long-term release.

SIGNIFICANCE

The fluoride release mechanism is intrinsically the same as determined for elutions in water. The increased amount of fluoride released under acidic conditions, especially in the long term, corroborates that an erosive leaching of the glass particles in the bulk of the cement accounts for the long-term fluoride release.

Fluoride release process of (resin-modified) glass-ionomer cements versus (polyacid-modified) composite resins

The fluoride release of conventional and resin-modified glass-ionomers is reviewed and compared to that of fluoride-releasing (polyacid-modified) composite resins. Each formulation displays a typical fluoride release profile. The cumulative amount of fluoride released is described by [F]c = [F](I)t/(t + t1/2) + beta square root t for glass ionomers whether resin-modified or not, whereas for composite resins this quantity is given by [F]c = [F](I)t/(t + t1/2) + alpha t. Both equations indicate that two kinetic processes are responsible for the fluoride release profiles. The kinetic parameters [F](I), t1/2, beta and alpha depend on the formulation. On the basis of the exchange characteristics for fluoride, an attempt is made to explain the mechanisms responsible for these fluoride release processes.

Fluoride release profiles of restorative glass ionomer formulations

OBJECTIVES

The amounts of fluoride released by different glass ionomer formulations were compared on the basis of individual fluoride release profiles in order to derive the effect of the physical and chemical formulation on the fluoride release process.

METHODS

The fluoride release profiles of each of five specimens of ten glass ionomer cements setting by an acid-base reaction were investigated. The profiles were obtained by determining the amount of fluoride released [F] after equilibrating the samples at 37 degrees C in distilled water for 140 d. The [[F],t]-profiles were compared with a Multivariate Data Analysis on the basis of a Principal Component Analysis.

RESULTS

The Multivariate Data Analysis reveals that eight of the ten glass ionomers can be classified into four distinct groups. When the cumulative amount of fluoride released by each sample, [F]c, is calculated and fitted as a function of time, a regression analysis (r > 0.99) reveals that [F]c for all samples is most adequately represented by [F]c = ([F]l x t)/(t + t1/2) + beta x square root of t, indicating that two kinetic processes are responsible for the fluoride release profiles.

SIGNIFICANCE

A comparison of the parameters of this equation shows that the physicochemical rationale for the classification of the glass ionomers conforms to differences in the kinetics of these processes which are determined by the qualitative and quantitative chemical composition as well as by the presentation (hand-mixed vs. capsules) of the glass ionomer. From the classification, it becomes apparent that different formulations can result in the same fluoride release profiles.