Juliano Sartori Mendonça

Clinical Evaluation of a 3% Potassium Oxalate Gel and a GaAlAs Laser for the Treatment of Dentinal Hypersensitivity

OBJECTIVES This study evaluated the immediate and 3 month clinical effects of a low-level gallium-aluminum-arsenide (GaAlAs) laser and a 3% potassium oxalate gel for the treatment of dentinal hypersensitivity. MATERIALS AND METHODS A total of 164 teeth from 30 patients with clinical diagnoses of dentinal hypersensitivity were selected for this randomized, placebo-controlled, double-blind clinical study. The teeth were randomized to three groups: GaAlAs laser, oxalate gel, and placebo gel. The treatment sessions were performed at 7 d intervals for four consecutive weeks. The degree of sensitivity in response to an air blast and tactile stimuli was assessed according to a visual analogue scale at baseline, immediately after the fourth application, and then 3 months after the fourth application. The reductions in dentinal hypersensitivity from baseline at the two follow-up assessments were evaluated as the main outcome. RESULTS In both the active and control groups, there were statistically significant reductions in dentinal hypersensitivity immediately after and 3 months after the treatments, when compared with the hypersensitivity at baseline. No significant differences among the three groups could be detected in their efficacy at either the immediate or 3 month evaluations irrespective of the stimulus. CONCLUSIONS The treatments under study were effective for reducing dentinal hypersensitivity, and longer observational periods could enhance the ability of studies to detect differences between active and placebo groups.

Effect of Surface Pretreatments on the Microtensile Bond Strength of Lithium-Disilicate Ceramic Repaired with Composite Resin

The aim of this study was to evaluate the influence of ceramic surface treatments and silane drying temperature on the microtensile bond strength (µTBS) of a resin composite to a lithium disilicate ceramic. Twenty blocks (7x7x5 mm) of lithium disilicate-based hot-pressed ceramic were fabricated and randomly divided into 4 groups: G1: acid etching with 9.5% hydrofluoric acid for 20 s and drying silane with room-temperature air; G2: acid etching with 9.5% hydrofluoric acid for 20 s and drying silane with 45 ± 5 °C warm air; G3: airborne-particle abrasion with 50 µm aluminum oxide particles and drying silane with 45 ± 5 °C warm air; G4: airborne-particle abrasion with 50 µm aluminum oxide particles and drying silane with air at room-temperature. After treatments, an adhesive system (Single Bond 2) was applied, light-cured and direct restorations were built up with a resin composite (Filtek Z250). Each specimen was stored in distilled water at 37 °C for 24 h and cut into ceramic-composite beams with 1 mm2 of cross-sectional area for µTBS testing. Statistical analysis was performed with one-way ANOVA and Student-Newman-Keuls test (α=0.05). µTBS means (S.D.) in MPa were: G1: 32.14 (7.98), G2: 35.00 (7.77) and G3: 18.36 (6.17). All specimens of G4 failed during the cutting. G1 and G2 presented significantly higher µTBS than G3 (p<0.05). There was no statistically significant difference between G1 and G2 (p>0.05). As far as the bond strength is concerned, surface pretreatment of lithium-disilicate ceramic with hydrofluoric acid and silane application can be used as an alternative to repair ceramic restorations with composite resin, while surface pretreatment with sandblasting should be avoided.

Effect of oxalic acid pre-treatment in restorations of non-carious cervical lesions: A randomized clinical trial

Context: Non-carious cervical lesions are usually associated with dentin hypersensitivity. The use of oxalic acid in restorations of these lesions could be beneficial in relieving pain. Aims: To evaluate the use of oxalic acid in restorations of non-carious cervical lesions. Settings and Design: A randomized clinical trial. Subjects and Methods: One operator placed 90 restorations in 20 volunteers of both sexes, with at least two lesions to be restored with the techniques: Control — Restoration with total-etch technique and Experimental — Restoration with pretreatment with oxalic acid followed by application of adhesive system. The restorative adhesive system used was XP Bond/Durafill. The restorations were directly assessed by two independent examiners using a modified United States Public Health Service (USPHS) method at baseline, 6 and 12 months, taking into account the following criteria: Retention (R), marginal integrity (MI), marginal discoloration (MD), postoperative sensitivity (S), caries (C), and anatomic form (AF). Statistical analysis used: The data were statistically analyzed using the Fisher exact and McNemar tests. The level of significance was set at 5%. Results: After 1 year, the results of restorations clinically satisfactory obtained for the control and experimental group respectively were: R (97% / 89%), MI (100% / 100%), MD (100% / 100%), S (100% / 100%), C (100% / 100%), and AF (100% / 100%). Conclusions: The use of oxalic acid as an agent of dentin pretreatment did not influence the clinical performance of restorations in non-carious cervical lesions after 1 year.

Two-year clinical evaluation of resin composite in posterior teeth: A randomized controlled study

Background: Clinical evaluations as fundamental method to prove the efficiency of restorative materials. Aim: This study evaluated the clinical performance of restorative systems during 2 years of clinical service. Materials and Methods: This study assessed the clinical performance of restorative systems (Filtek Z250 and P60), during 2 years of clinical service, using the US Public Health Service system. The randomized and double-blind study comprising thirty volunteers. The restorations were evaluated at baseline, 6, 12, and 24 months. It was used the following criteria: marginal discoloration (MD), marginal integrity (MI), superficial texture (ST), wear (W), postoperative sensitivity (PS) and recurrent caries (RC). Results: Statistic analysis was performed using Fishers and McNemars exact tests and Pearsonss Chi-square in a significance level of 5%. The results at baseline and 24 months for Group I were: MD – 100, 100%; MI – 100, 88.6%; ST – 100, 94.3%; W – 100, 94.3%; PS – 100, 100%; RC – 100, 100%, of alpha scores; Group II: MD – 100, 97.1%; MI – 100, 91.4%; ST – 100, 94.3%; W – 100, 91.4%; PS – 100, 100%; RC – 100, 100%, of alpha scores. It was observed no statistical difference in the evaluated criteria and period. Conclusions: After 24 months of evaluation, both restorative systems exhibited acceptable clinical performance.