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Biomedical subjects

D Pasqualini

Publications and source records attributed to D Pasqualini.

4 recordsLinked to original sources

Influence of sodium hypochlorite on fracture properties and corrosion of ProTaper Rotary instruments.

AIM: To evaluate the influence of immersion in NaOCl on resistance to cyclic fatigue fracture and corrosion of ProTaper NiTi Rotary instruments. METHODOLOGY: A total of 120 new ProTaper NiTi Rotary files (F2) were randomized and assigned to three different groups of 40 each. Group 1 was the control group; 20 mm (excluding the shaft) of group 2 instruments were immersed in 5% NaOCl at 50 degrees C for 5 min; instruments in group 3 were completely immersed in 5% NaOCl at 50 degrees C for 5 min. All instruments were then tested for cyclic fatigue, recording the time in seconds to fracture. Data were analysed by the Kruskall-Wallis test and post-hoc multiple comparisons (P < 0.05). Micromorphological and microchemical analyses were also completed by means of a field emission scanning electron microscopy (SEM) on those instruments in group 3 that had undergone early fracture. RESULTS: Instruments in group 3 had a significantly lower resistance to fracture because of cyclic fatigue than those in groups 1 and 2 (P < 0.001). In some instruments in group 3, early fracture occurred after only a few seconds of fatigue testing. SEM observations revealed evident signs of corrosion of the fractured instruments. CONCLUSION: Group 3 had significantly reduced resistance to cyclic fatigue compared with instruments in groups 1 and 2. The phenomenon of early fracture may be attributed to galvanic corrosion induced by the presence of dissimilar metals, where one acts as the cathode of a galvanic couple, established when the instrument is immersed in NaOCl solution. The NiTi alloy may acts as the anode and thus undergoes corrosion.

Corrosion↗

Primary and secondary closure of the surgical wound after removal of impacted mandibular third molars: a comparative study.

Primary and secondary closure techniques after removal of impacted third molars were compared in terms of post-operative pain and swelling. Two hundred patients with impacted third molars were randomly divided into two groups of 100. Panoramic radiographs were taken to assess degree of eruption and angulation of third molars. Teeth were extracted, and in Group 1 the socket was closed by hermetically suturing the flap. In Group 2 a 5-6 mm wedge of mucosa adjacent to the second molar was removed to obtain secondary healing. Swelling and pain were evaluated for 7 days after surgery with the VAS scale. The statistical analysis (*analysis of variance for repeated measures, P < 0.05) showed that pain was greater in Group 1, although it decreased over time similarly in the two groups (P = 0.081, F(6,198) = 3.073*). Swelling was significantly worse in Group 1 (P < 0.001, F(6,198) = 44.30*). In Group 1, dehiscence of the mucosa was present in 33% of patients at day 7, and 2% showed signs of re-infection with suppurative alveolitis at 30 days. Pain and swelling were less severe with secondary healing than with primary healing.

Adult↗

Third molar extraction. Current trends.

Extraction of third molars is the operation most frequently performed by oral and maxillofacial surgeons. The American National Institute of Health (1979) and the American Association of Oral and Maxillofacial Surgeons (1993) have organised consensus conferences to systematically analyse the scientific evidence and provide official guidelines for the management of third molars. However, some clinical aspects are still controversial: indications for preventive extraction, early extraction, prognosis of impacted teeth, continuous follow-up, relationship with anterior crowding and temporo-mandibular disorders. This article reviews the conclusions from the consensus conferences and integrates them with more recent data. The actual trend seems to justify a more conservative clinical approach rather than an aggressive extraction policy.

Adolescent↗