Comparison of postoperative pain after root canal treatment using reciprocating instruments based on operator's experience: A prospective clinical study.

BACKGROUND: The aim of the present study was to compare clinically the incidence of postoperative pain after endodontic treatment using the Reciproc System, taking into account the operator's experience. MATERIAL AND METHODS: One hundred patients scheduled for routine endodontic treatment were enrolled in this study. Endodontic treatment was carried out in a single visit by undergraduate and postgraduate students. The chemomechanical preparation of root canals was performed with Reciproc instruments. Pretreatment and postoperative pain was recorded using a visual analogue scale (VAS). Postoperative pain and the need for analgesic consumption were assessed at 4, 8, 16, 24, 48 and 72 hours post-treatment. The data were analyzed using the Mann-Whitney U and Chi-Square test, and the significance was set at P<0.05. RESULTS: The mean value of pain after root canal treatment was 1.13±1.94 and 1.91±2.07 on a VAS between 0 and 10 in treatments performed by undergraduate and postgraduate students, respectively. There was a significant difference in the incidence of postoperative pain between the two groups (P<0.05). CONCLUSIONS: The prevalence of postoperative pain was high in the treatments performed by postgraduate students in comparison with undergraduate students. This suggests that operator experience has an influence on the prevalence of postoperative pain after root canal treatment. Key words:Post-endodontic pain, root canal treatment, reciprocating systems, Expert operators Inexperienced operators.

In vivo and in vitro spectrophotometric evaluation of upper central incisors before and after extraction.

OBJECTIVES: This in vivo and in vitro study investigated the influence of pulpal vitality on the optical properties of teeth over a 1-month period. MATERIALS AND METHODS: We monitored two specific areas (2-mm-thick pure enamel and 3-mm-thick enamel-dentine complex) in 10 teeth against two backgrounds (white and black) using a calibrated reflectance spectrophotometer at the following time points: before extraction (T0); immediately after extraction (T1); at 1-day post-extraction (T2); at 1-week post-extraction (T3); and 1-month post-extraction (T4). We recorded tooth colour based on the Commission Internationale d'Eclairage L*a*b* model and translucency and analysed these characteristics over time using analysis of variance. RESULTS: The 2-mm-thick pure enamel area showed significant changes (p > 0.05) in L*, a* and b* values between before and 1 month after extraction (T0-T4). Translucency was detectable between (T0-T3) and (T0-T4). The 3-mm-thick enamel-dentine complex also exhibited significant differences (p > 0.05) in L*, a* and b* values within (T0-T4). Translucency value changes significantly (p > 0.05) within the first day (T0-T2) and (T0-T3). CIEDE 2000 DE values revealed no statistically significant differences (p < 0.05) in colour between the T0 L*a*b* measures and all the subsequent measures at times T1, T2, T3 and T4. CONCLUSIONS: Within the limitations of this study, we conclude that the optical characteristics (i.e. colour and translucency) of teeth change after extraction. CLINICAL RELEVANCE: The results help understanding the precise moment when the colour of extracted tooth changes to identify optimum time to use a tooth for scientific investigation and determine whether it is necessary to extract pulp tissue beforehand.

Comparative study of interim materials for direct fixed dental prostheses and their fabrication with CAD/CAM technique.

STATEMENT OF PROBLEM: Prosthodontic treatment sometimes requires a long-term interim fixed dental prosthesis (FDP) until the definitive restoration can be cemented. However, some interim materials are weak and do not have an adequate marginal seal. PURPOSE: The purpose of this study was to compare the marginal fit and fracture strengths of interim FDPs fabricated by using a direct technique with different materials (Structur 3, Trim, and DuraLay) with interim prostheses (Telio CAD) made with a computer-aided design and computer-aided manufacturing (CAD/CAM) system. MATERIAL AND METHODS: Seventy interim FDPs were fabricated by using different materials (Structur 3, Trim, DuraLay, and Telio CAD) on a metal master model. Resin-impregnated, light-polymerizing glass fiber (GrandTEC) was used to reinforce 10 interim FDPs per material fabricated with the direct technique. Interim FDPs were stored at 37°C for 24 hours before thermocycling. Marginal fit was analyzed at 6 points in each interim FDP before and after thermocycling with either 2500 or 5000 cycles. After fracturing the interim FDPs with a universal testing machine, fracture strength, fragments separation, and fracture point were recorded. Marginal fit data were analyzed with 2-way repeated measure analysis of variance (ANOVA), fracture strength with 1-way ANOVA, and fragments separation and fracture point with the chi-square test at a 99% confidence interval. RESULTS: All interim materials showed marginal discrepancies over time, but no significant differences were found among groups (P>.001), except in the marginal fit of interim FDPs reinforced with glass fiber (S3F), which showed the smallest marginal gap after 5000 cycles (P<.001). Reinforced interim FDPs (S3F, TMF, and DLF) and CAD/CAM FDPs (TCC) presented a fracture strength ranging between 471.3 ±62.4 N and 531.1 ±150.1 N (P>.001). Finally, significant differences were observed in the fracture point and frequency of separation (P<.001). CONCLUSIONS: Bis-acryl reinforced with glass fiber showed the least marginal discrepancy. No differences were found between the fracture strengths of interim FDPs fabricated with CAD/CAM system and interim FDPs reinforced with glass fiber. No significant difference in fracture strength was observed between interim FDPs reinforced with glass fiber and prostheses fabricated with CAD/CAM system. However, unreinforced interim FDPs showed the lowest fracture strength.

Colour stainability of indirect CAD-CAM processed composites vs. conventionally laboratory processed composites after immersion in staining solutions.

OBJECTIVES: The aim of this study was to determine, by using a spectrophotometer device, the colour stainability of two indirect CAD/CAM processed composites in comparison with two conventionally laboratory-processed composites after being immersed 4 weeks in staining solutions such as coffee, black tea and red wine, using distilled water as control group. METHODS: Two indirect CAD/CAM composites (Lava Ultimate and Paradigm MZ100) and two conventionally laboratory-processed composites (SR Adoro and Premise Indirect) of shade A2 were selected (160 disc samples). Colour stainability was measured after 4 weeks of immersion in three staining solutions (black tea, coffee, red wine) and distilled water. Specimen's colour was measured each week by means of a spectrophotometer (CIE L*a*b* system). Statistical analysis was carried out performing repeated ANOVA measurements and Tukey's HSD test to evaluate differences in ΔE00 measurements between groups; the interactions among composites, staining solutions and time duration were also evaluated. RESULTS: All materials showed significant discoloration (p<0.01) when compared to control group. The highest ΔE00 observed was with red wine, whereas black tea showed the lowest one. Indirect laboratory-processed resin composites showed the highest colour stability compared with CAD/CAM resin blocks. CONCLUSIONS: CAD/CAM processed composites immersed in staining solutions showed lower colour stability when compared to conventionally laboratory-processed resin composites. CLINICAL SIGNIFICANCE: The demand for CAD/CAM restorations has been increasing; however, colour stainability for such material has been insufficiently studied. Moreover, this has not been performed comparing CAD/CAM processed composites versus laboratory-processed indirect composites by immersing in staining solutions for long immersion periods.

Color stability of siloranes versus methacrylate-based composites after immersion in staining solutions.

OBJECTIVES: The purpose of this study was to determine, by using a spectrophotometer device, the color stability of silorane in comparison with four methacrylate-based composites after being immersed in different staining solutions such as coffee, black tea, red wine, orange juice, and coke, and distilled water as control group. METHODS: Four restorative methacrylate-based composites (Filtek Z250, TetricEvoCeram, Venus Diamond, and Grandio) and one silorane (FiltekSilorane) of shade A2 were selected to measure their color stability (180 disk samples) after 4 weeks of immersion in six staining solutions: black tea, coffee, red wine, orange juice, coke, and distilled water. The specimen's color was measured each week by means of a spectrophotometer (CIE L*a*b* system). Statistical analysis was carried out performing an ANOVA and LSD Test in order to statistically analyze differences in L*a*b*and ∆E values. RESULTS: All materials showed significant discoloration (p < 0.05) when compared to the control group (immersed in distilled water). The Highest ∆E observed was with red wine, whereas coke led to the lowest one. Silorane showed the highest color stability compared with methacrylate-based composites. CONCLUSIONS: Methacrylate-based materials immersed in staining solutions showed lower color stability when compared with silorane. Great differences in ∆E were found among the methacrylate-based materials tested. CLINICAL RELEVANCE: Although color stability of methacrylate-based composites immersed in staining solutions has been widely investigated, this has not been done for long immersion periods with silorane-based composites.

Optical integration and fluorescence: a comparison among restorative materials with spectrophotometric analysis.

OBJECTIVE: To evaluate the optical integration and fluorescence of three contemporary restorative materials used for incisoproximal restorations. METHOD AND MATERIALS: A microfilled hybrid composite (Amaris, VOCO; MHC), a nanofilled hybrid composite (Grandio, VOCO; NHC), and an experimental ormocer (VOCO; ORM) were used to consecutively restore 10 extracted incisors with incisoproximal restorations using the natural layering concept, mimicking the natural anatomy of the tooth. Before and after placement of each restoration, the teeth were photographed under standardized conditions (direct, indirect, and fluorescent light), and spectrophotometric measurements (SpectroShade, Handy Dental Type 713000, MHT) were made using a black-and-white background. Between measurements, the teeth were allowed to rehydrate for 2 weeks. Ten independent evaluators scored each light condition using an optical integration score on a scale from 0 to 10 (0 = worst optical integration, restoration can be easily distinguished from remaining tissue; 10 = optimal optical integration). Differences in L*a*b and DE values and optical integration scores were statistically analyzed using ANOVA. RESULTS: MHC obtained the highest optical integration and fluorescence scores (P < .01), followed by NHC, although there were no statistically significant differences found among DE of the restorative materials. ORM achieved the worst optical integration and fluorescence. CONCLUSION: The microfilled hybrid composite obtained the highest optical integration scores (P < .01), followed by the nanofilled hybrid composite. The experimental ormocer showed the least favorable optical behavior. Spectrophotometric measurements showed no statistically significant differences among all three restorative materials.

Estudio comparativo entre las pruebas de ELISA e inmunodifunsión en el diagnóstico de la Leucosis Enzoótica Bovina / Comparative study of the agar gel immunodiffusion test and the ELISA test in the bovine enzootic lymphosarcoma

EL Linfosarcoma Enzoótico Bovino (LEB) es el problema neoplásico más común e importante por las pérdidas económicas que ocasiona, principalmente en el ganado lechero. En México escasea la información concerniente al LEB. El objetivo del presente trabajo fue comparar la efectividad de las pruebas de Inmunodifusión en gel de agar y ELISA para el diagnóstico de la enfermedad en sueros de bovinos Holstein Friesian. Se formaron tres grupos de 10 animales cada uno y uno cuarto grupo con 15 animales. El primero consistió en animales seropositivos con leucocitosis persistentes (LP), el segundo en seropositivos sin presentación enzoótica de la enfermedad y sin LP, y el tercero con LEB, comparados con un grupo testigo de 15 animales clínicamente sanos y negativos serológicamente al Virus de la Leucosis Bovina (VLB). Se obtuvieron tres muestras sanguíneas de cada animal con intervalos de un mes para cada una. Las dos pruebas resultaron ser igualmente específicas. Los mayores títulos de anticuerpos se detectaron en el grupo 1, sin correlación directa entre éstos y la presentación de la enfermedad. Los títulos de anticuerpos detectados con la prueba de ELISA no variaron durante los tres muestreos de los grupos infectados.