Ex vivo comparison of radiographic and electronic root canal length measurements in primary molars.

AIM: The aim of the study was to evaluate the accuracy of root canal length measurements of primary teeth using an electronic apex locator (EAL) and digital radiography in comparison to stereomicroscopic measurement as gold standard. MATERIALS AND METHODS: After preparation of access cavities of twenty extracted primary molars, the teeth were embedded in alginate blocks. Endodontic files were inserted in the root canals and the length was measured using ProPex II (Dentsply, Maillefer). When the reading was stable for 5s a silicone stop was used for reference. The true lengths of the files were then measured using a micrometer. The gold standard was determined by observing the tip of the file at the apical foramen under a stereomicroscope. For radiographic measurements standard images were obtained at 30 cm source-to-object distance, and zero degrees vertical and horizontal angulations. Radiographic images of each experimental tooth were obtained with the Digora Storage Phosphor Plates (SPP) (Soredex, Orion Corporation, Helsinki, Finland) with the x-ray unit operating at 65 kVp and 10 mA for 0.16 seconds (Trophy Radiologie, Vincennes, France). The radiographic root lengths were measured with the measurement tool of the Digora for Windows software. The mean measurements of both methods were compared to the gold standard measurements using Repeated Measure ANOVA test with Bonferroni adjustments to identify the pair-wise differences (p=0.05). RESULTS: The mean measurements obtained with the EAL (14.06±1.89 mm) were significantly lower than measurements done with SPP images (14.24±1.98 mm) (p<0.05). However, when both root canal length measurement techniques were compared to stereomicroscopic measurements (gold standard), no statistically significant difference was found. CONCLUSION: The EAL might be safer than digital radiography for the measurement of root canal length in primary teeth.

Comparison of the remineralisation effect of a glass ionomer cement versus a resin composite on dentin of primary teeth.

AIM: The aim of this study was to investigate the interaction of a high viscosity glass ionomer cement (GIC) and a composite resin with caries affected dentin and to determine the remineralization levels. MATERIALS AND METHODS: In a split mouth design 24 GIC and composite resin atraumatic restorative treatment restorations were made in vivo and the teeth were collected after 2 years and subsequently sectioned and examined using Vickers microhardness test; the latter was performed starting from the dentin surface adjacent to the restoration. Repeated Measure ANOVA and Bonferroni statistical methods were used for data analysis. RESULTS: The microhardness adjacent to the GIC restorative material resulted to be significantly higher. CONCLUSION: GIC resulted to be a better restorative material for the remineralization of caries affected dentin, though further studies are necessary for the corroboration of this finding. The GIC restored primary molar dentin had a higher level of remineralization and GIC could be the material of choice in pediatric dentistry.

Effect of acidic solution viscosity on enamel erosion.

The objective of this in vitro study was to investigate the effects of viscosity changes of different acidic solutions on dental erosion. Bovine enamel samples (n = 240, Ø = 3 mm) were embedded in acrylic resin and were allocated to 30 groups (n = 8). Citric acid (CA) and phosphoric acid (PA) solutions at pH 2.5, 3, and 3.5 were prepared in de-ionized water (titratable acidity to pH 5.5: 31 ± 0.6 mmol OH(-)/l). The kinetic viscosities of the acidic solutions were adjusted to 1.5, 3, 6, 12, and 24 mm(2)/sec by the addition of hydroxypropyl cellulose (HPC) at different concentrations. Solutions were pumped over the enamel surface from a reservoir with a drop rate of 1 mL/min. Each specimen was eroded for 10 min at 20 °C. Erosion of enamel surfaces was measured by profilometry. Data were analyzed by analyses of variance and logarithmic regression analyses (p < 0.05). Enamel loss was dependent on viscosity, pH, and the kind of acid. The regression analyses showed that higher viscosity caused lower enamel erosion for both acids and all pH levels. Dental erosion is dependent not only on chemical factors of the acid, like pH and acid type, but also on acid viscosity.