A study of post-operative sensitivity in class I and class II restorations with self-etching adhesive and nanofilled composite.

AIM: The aim of the study was to determine the type, intensity and duration of post operative sensitivity (POS) in class I and II cavity restorations with self-etching adhesive and nanofilled composite. PATIENTS AND METHODS: The clinical study included 34 patients, who received a total of 76 restorations by undergraduate dental students. The restorations were made in medium and deep cavities. Self-etching adhesive Adper Promp L-Pop and nanocomposite Filtek Supreme (3MESPE Dental products USA) were placed. The type, the magnitude and the duration of postoperative sensitivity were examined on days 1, 3, 5, 7, 14 and 30. Intensity of sensitivity perceptions were recorded on a visual analogue scale using the method of self-observation. Parametric and non-parametric analyses were employed at a significance level of P < 0.05. RESULTS: Pressure-dependent POS was present in most of the cases (15.78% +/- 4.209), followed by discomfort (9.21% +/- 3.340) and pressure- and cold-induced pain (1.33% +/- 1.147). A statistically significant difference was found between days 1 and 3, and between days 5 and 30, as well as between days 7 and 30 (Wilcoxon Signed Ranks Test, P < 0.05). Rapidly disappearing POS (within 1 week) had the highest percentage: 75% +/- 9.934. CONCLUSIONS: Following restoration of class I and II cavities with self-etching adhesive and nanofilled composite POS was established in 26.3% of the cases.

Injection Shrinkage аnd Water Sorption of Some Thermoplastic Dental Materials

Objective: To evaluate the change of diameter of different injection-molded thermoplastic materials. Material and Methods: Four thermoplastic injection-molded materials were analyzed (Bre.flex 2nd edition, Vertex ThermoSens, Perflex Biosens and Polyan IC). A total of 432 test samples were made in the form of an "hourglass". All samples were divided into three groups: Group I (Control) - consisting of 36 test samples for each type of material, that was not exposed to artificial aging or a wet environment; Group II - consisting of 36 test samples for each type of material, that were artificially aged through dehydration; Group III - specimen were subjected to artificial aging without dehydration. The diameter of each specimen was measured with a digital caliper. Data were analysed using the Student's t-test. Results: Regarding to shrinkage, the samples from the Bf Control group have a mean value of 1.56 mm and was observed a shrinkage of the injection-molded polyamide material within 0.25%. The comparison between the samples from Group II and Group III showed statistically significant differences (p<0.001). There were no significant differences between groups for Thermosens and Biosens (p>0.05). The comparison between Group II and Group III for Polyan IC samples shows that Group III has a higher arithmetic mean value (p<0.01). Conclusion: Shrinkage of the polymers during the injection process is present in all materials. The thermocycling and the storage in a dry or in a wet environment of the samples results in a change of the diameter in almost every single type of material.