The Caries Assessment Spectrum and Treatment (CAST) index: rational and development

Serious difficulties in reporting results were encountered when using ICDAS II and PUFA separately in an epidemiological survey in a child population in Brazil. That necessitated the development of a comprehensive but pragmatic caries assessment index. This publication describes the rationale, development and content of a novel caries assessment index. Strengths and weaknesses of ICDAS II, PUFA and other indices were analysed. The novel caries index developed for use in epidemiological surveys is termed 'Caries Assessment Spectrum and Treatment' (CAST). 'Spectrum' indicates what is considered the main strength of the new index - its usefulness in describing the complete range of stages of carious lesion progression: from no carious lesion, through caries protection (sealant) and caries cure (restoration) to lesions in enamel and dentine, and the advanced stages of carious lesion progression in pulpal and tooth-surrounding tissue. CAST combines elements of the ICDAS II and PUFA indices, and the M- and F-components of the DMF index. A DMF score can easily be calculated from the CAST score, thereby enabling retention of the use of existing DMF scores. The CAST index for use in epidemiological surveys is very promising. It should be validated and its reliability and usefulness be tested in different age groups in different countries and cultures.     

Oral events related to low-dose methotrexate in rheumatoid arthritis patients

Low-dose methotrexate (MTX) is frequently used for patients with rheumatoid arthritis (RA). High doses of MTX frequently produce side effects. The aim of this study was to explore oral complications of low-dose MTX therapy in a population of RA patients. This is a cross-sectional study in which oral examination was performed on a population of RA patients. Patients undergoing MTX therapy (5-20 mg weekly) for at least six months were included in the study group, and RA patients being treated under another regimen were used as controls. The frequency of oral lesions was compared between groups. The chi-square test was used to compare frequencies. Relative risk (RR) and its confidence interval (CI) were established. Significance level was set at 0.05. Twenty-eight RA patients on a low-dose MTX regimen and 21 controls were enrolled in the study. Oral lesions were found in 22 patients (78.6%) undergoing MTX therapy, and in 5 patients (23.8%) undergoing other therapies (p < 0.001). There were no significant differences regarding age, gender or dosage. The most common oral events observed in patients in the MTX group were ulcerative/erosive lesions (60.7%) and candidiasis (10.7%). Patients in the control group presented lower prevalence of the same lesions (p < 0.001). The RR for developing oral lesions was 11.73 (CI 2.57 - 58.98), with low-dose MTX therapy. In conclusion, the prevalence of oral mucosa lesions in RA patients receiving low doses of MTX therapy is higher than in RA patients not receiving the drug.     

Synthesis and biocompatibility of an experimental glass ionomer cement prepared by a non-hydrolytic sol-gel method

The aims of this study were to demonstrate the synthesis of an experimental glass ionomer cement (GIC) by the non-hydrolytic sol-gel method and to evaluate its biocompatibility in comparison to a conventional glass ionomer cement (Vidrion R). Four polyethylene tubes containing the tested cements were implanted in the dorsal region of 15 rats, as follows: GI - experimental GIC and GII - conventional GIC. The external tube walls was considered the control group (CG). The rats were sacrificed 7, 21 and 42 days after implant placement for histopathological analysis. A four-point (I-IV) scoring system was used to graduate the inflammatory reaction. Regarding the experimental GIC sintherization, thermogravimetric and x-ray diffraction analysis demonstrated vitreous material formation at 110oC by the sol-gel method. For biocompatibility test, results showed a moderate chronic inflammatory reaction for GI (III), severe for GII (IV) and mild for CG (II) at 7 days. After 21 days, GI presented a mild reaction (II); GII, moderate (III) and CG, mild (II). At 42 days, GI showed a mild/absent inflammatory reaction (II to I), similar to GII (II to I). CG presented absence of chronic inflammatory reaction (I). It was concluded that the experimental GIC presented mild/absent tissue reaction after 42 days, being biocompatible when tested in the connective tissue of rats.     

Influence of the degree of dentine mineralization on pulp chamber temperature increase during resin-based composite (RBC) light-activation

Objectives

To analyse the influence of the degree of dentine mineralization on the pulp chamber temperature increase during composite light-activation.

Methods

Dentine discs (2 mm thick) obtained from recently extracted teeth or those with extensive dentine sclerosis were analysed by FT-IR spectrometry in order to choose the two discs with the greatest difference in the degree of mineralization. A model tooth was set up with the dentine discs between a molar with the pulp chamber exposed and a crown with a standardized class II cavity. A K-type thermocouple was introduced into the molar root until it came into contact with the dentine discs and the cavity was filled with P60 resin composite. The temperature rise was measured for 120 s after light-activation began: Standard (S) 600 mW/cm²/40 s; Ramp (R) 0 → 800 mW/cm²/10 s + 800 mW/cm²/10 s; Boost (B) 850 mW/cm²/10 s and LED (L) 1.300 mW/cm²/40 s (n = 10). The same protocol was repeated after grinding the dentine discs to 1.0 and 0.5 mm thickness.

Results

The temperature increase was significantly higher in dentine with high degree of mineralization (p < 0.05). With respect to the dentine thickness, the following result was found: 2 mm < 1 mm < 0.5 mm (p < 0.05). The light-activation mode also presented significant difference as follows: S > R = L > B (p < 0.05).

Conclusions

The higher the degree of dentine mineralization the greater the increase in pulp chamber temperature. The temperature increase was influenced by the light-polymerization mode and dentine thickness.     

Bonding properties of universal adhesives to root canals prepared with different rotary instruments

Statement of problem

Preparation of coronal dentin by using a diamond rotary instrument usually results in higher bond strength values than preparation with tungsten carbide burs, but information is lacking about the influence of rotary instruments on root canals before the bonding of fiber posts.

Protection of short-time enamel erosion by different tetrafluoride compounds

OBJECTIVE: This in vitro study aimed to analyse the protective effect of differently concentrated titanium (TiF(4)), zirconium (ZrF(4)) and hafnium (HfF(4)) tetrafluoride on enamel erosion. METHODS: Polished enamel surfaces of 36 bovine crowns were covered with tape leaving 4 enamel windows each 3mm in diameter exposed. The crowns were randomly assigned to six groups (each n=6) and pretreated with 4% TiF(4), 10% TiF(4), 4% ZrF(4), 10% ZrF(4), 4% HfF(4) or 10% HfF(4) for 4 min (first window), 10 min (second window) or 15 min (third window). The fourth window of each crown was not pretreated and served as control. Erosion was performed stepwise with 1% HCl (pH 2) in five consecutive intervals of each 15 s (total 75 s). Enamel dissolution was quantified by colorimetric determination of phosphate release into the acid. For each tooth, cumulative phosphate loss of enamel pretreated with one of the tetrafluoride compounds was calculated as percentage of the respective control and statistically analysed using two-way ANOVA. RESULTS: Enamel erosion was significantly reduced by TiF(4), ZrF(4) and HfF(4) application. Cumulative phosphate loss (mean % of control, 75s erosion) after 4-15 min application was significantly lower for 4% ZrF(4) (7-11%), 10% ZrF(4) (2-6%), 4% HfF(4) (11-9%) and 10% HfF(4) (12-16%) compared to 4% TiF(4) (42-27%) and 10% TiF(4) (54-33%). Only for 4% and 10% TiF(4), phosphate loss decreased with increasing duration of application, but also increased with increasing acid intervals. CONCLUSION: TiF(4), ZrF(4) and HfF(4) might protect enamel against short-time erosion, but protection was more enhanced by ZrF(4) and HfF(4) compared to TiF(4) application overtime.     

Validity of multislice computerized tomography for diagnosis of maxillofacial fractures using an independent workstation

OBJECTIVE: The purpose of this study was to demonstrate the sensitivity and specificity of multislice computerized tomography (CT) for diagnosis of maxillofacial fractures following specific protocols using an independent workstation. STUDY DESIGN: The study population consisted of 56 patients with maxillofacial fractures who were submitted to a multislice CT. The original data were transferred to an independent workstation using volumetric imaging software to generate axial images and simultaneous multiplanar (MPR) and 3-dimensional (3D-CT) volume rendering reconstructed images. The images were then processed and interpreted by 2 examiners using the following protocols independently of each other: axial, MPR/axial, 3D-CT images, and the association of axial/MPR/3D images. The clinical/surgical findings were considered the gold standard corroborating the diagnosis of the fractures and their anatomic localization. The statistical analysis was carried out using validity and chi-squared tests. RESULTS: The association of axial/MPR/3D images indicated a higher sensitivity (range 95.8%) and specificity (range 99%) than the other methods regarding the analysis of all regions. CONCLUSION: CT imaging demonstrated high specificity and sensitivity for maxillofacial fractures. The association of axial/MPR/3D-CT images added important information in relationship to other CT protocols.     

Microtensile bond strength of self-etching adhesives to enamel and dentin

PURPOSE: To measure the microtensile bond strength to enamel and dentin of three self-etching adhesives in comparison with a total-etch two-step system as a control. MATERIALS AND METHODS: A total of 40 extracted human molars were stored in saline solution until use, then divided into 4 groups of 10 teeth (one group per adhesive system). Half of each of these groups underwent bond strength tests on enamel, and the other half was used for adhesion testing on dentin. The following experimental groups (n = 5) were then formed: E(1) Adper Prompt-L-Pop (AP, 3M ESPE) on enamel; E(2) Xeno CF II (X, Sanking Kogyo) on enamel; E(3) AdheSE (AS, Ivoclar-Vivadent) on enamel; E(4) Excite (EX, Ivoclar-Vivadent) on enamel; D(1) AP on dentin; D(2): X on dentin; D(3) AS on dentin; D(4) EX on dentin. Each tooth yielded 15 to 20 sticks about 0.9 x 0.9 mm in cross-sectional area for microtensile testing. Specimens were loaded in tension at a crosshead speed of 0.5 mm/minute, and bond strength at failure was calculated in MPa. A two-way ANOVA was applied to test for significance of the differences among the groups. RESULTS: The bond strength values of Excite (the control) were significantly higher than those of the test products on enamel (42.92+/-4.8 MPa) and on dentin (45.80+/-5.79 MPa). The self-etching adhesives AdheSE (28.48+/-4.71 MPa) and Xeno CF II (27.22+/-2.74 MPa) revealed significantly stronger adhesion than Adper Prompt-L-Pop (20.16+/-2.07 MPa) on dentin. On enamel, all self-etching test materials performed similarly. The substrate did not appear to have a significant influence on adhesion, as each material reached comparable levels of bond strength on enamel and dentin. CONCLUSION: On both substrates the self-etching adhesives tested performed significantly worse than did the total-etch system.