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AIM: To evaluate the reproducibility of 7 validation methods used for caries diagnosis in primary teeth. METHODS: Seventy-two occlusal sites were selected on 40 primary molars. The sites were evaluated independently by 3 experienced examiners using validation methods that involved direct assessment, i.e. by using a (1) magnifying glass (8×) and (2) stereomicroscope (35×), or indirect assessment i.e. by using (3) photographs, (4) slide projections of photographs, (5) stereomicroscope (35×) photographs, (6) stereomicroscope (35×) slide projections, and (7) projections of polarised light microscope slides. Cohen's kappa coefficients were calculated and subjected to the Kruskal-Wallis test at a significance level of 5%. RESULTS: The mean inter-examiner kappa values for the validation methods were 0.31-0.51. There were statistically significant differences (p<0.05) between methods 1 and 3, 1 and 4, 2 and 4, 4 and 5, 4 and 6, and 4 and 7. Moderate agreement was observed for all methods except methods 1 and 4, for which the agreement was fair. CONCLUSIONS: The inter-examiner agreement for all validation methods for caries diagnosis was moderate, except for the method based on indirect assessment by slide projection, which showed low agreement.

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AIM: To evaluate in a laboratory setting the performance of five methods for the determination of root canal length in primary anterior teeth. METHODOLOGY: Twenty extracted primary incisors, with at least two-thirds of the root, were used. After access cavity preparation, the teeth were embedded in alginate mixed with 0.9% sodium chloride solution. One operator determined root canal length using tactile sense (T), conventional radiography (RAD), tactile sense and conventional radiography (T + RAD), digital radiography (RDIG) and Root ZX electronic apex locator (EAL) methods. Next, the actual length (AL) was visually determined using a K-file from the coronal reference to the apical foramen or apical resorption level. The measurements obtained through each method were compared to the AL using the intraclass correlation coefficient (ICC) with the limits of agreement calculated with Bland and Altman analysis. The measurements were classified as acceptable (+/-1 mm from the AL) or not (>1 mm shorter or longer), and the McNemar test was employed for method comparison. RESULTS: Differences, limits of agreement and ICCs for each method were respectively EAL = -0.29; -1.02 to 0.44; 0.990; T + RAD = 0.17; -2.18 to 2.51; 0.929; RAD = 0.50; -3.41 to 4.41; 0.818; RDIG = 0.95; -3.76 to 5.65; 0.700; and T = -0.48; -5.59 to 4.64; 0.499. The most accurate and acceptable method was the EAL, followed by the T + RAD. : The EAL method performed best for root canal length determination in primary teeth.

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The influence of the method of storage of teeth and the effect of two kinds of dentin-bonding agents on the microleakage at the axial and cervical walls of composite restorations, in primary second molars, were evaluated. The samples were divided in three groups: Dehydrated, Hydrated and Frozen. The Dehydrated group was kept dry, the Hydrated group was stored in physiological saline solution under refrigeration, and the Frozen group was kept in the freezer, also immersed in physiological solution. The samples received two vertical slot preparations: a mesio-occlusal and a disto-occlusal one. In the mesio-occlusal cavities, Scotchbond Multi-Use adhesive system was used, whereas in the disto-occlusal cavities Prime & Bond 2.1 system was used, and all cavities were filled with Solitaire composite resin. The groups were then thermocycled and immersed in silver nitrate solution. Microleakage was measured by means of a digitized image system and the values were submitted to statistical analysis. The results showed that the method of storage had no statistically significant influence on marginal microleakage. Microleakage at the cervical wall was significantly greater than that at the axial wall, with 99.9% of certainty. The adhesive systems did not show significant influence on microleakage, in the studied methods of storage. However, there was statistical difference in the Dehydrated group samples, with the use of Prime & Bond 2.1 adhesive, when considering the margins of the restoration (axial and cervical).

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The purpose of this study was to compare the histological appearance of the pulp of human primary molars with active and arrested lesions. The sample consisted of 36 primary molars (18 with active lesions and 18 with arrested lesions) extracted from 35 children between 5 to 9 years of age. The histological diagnosis was classified in normal pulp, transitional stage, partial pulpitis, total pulpitis and total necrosis, and then subdivided in three subgroups: treatable, untreatable and questionable. Results showed that normal pulp or transitional stage (treatable category) was diagnosed in 50% of teeth with arrested lesions, compared to 11.1% of teeth with active lesions. Partial pulpitis (questionable category) was present in 38.8% with arrested lesions compared to 22.2% with active lesions. Total pulpitis and total necrosis (untreatable category) was diagnosed in 11.2% with arrested lesions compared to 66.7% with active lesions. The observed frequencies of histological categories between both groups were statistically significant (P < 0.05). Histologically, pulp reaction under active and arrested lesions in primary molars revealed the formation of a basophilic calcio-traumatic line at the junction of the primary and reparative dentin, formation of reparative dentin and a regular odontoblastic layer in 60% of the cases. Results indicated that the type of lesion (active or arrested) is a good indicator of the histological status of the pulp.

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