Local anesthesia is performed in dentistry before clinical procedures to avoid pain. Children can show fear at the sight of the needle and pain at its insertion. To make local anesthesia more comfortable, the use of computer-controlled local anesthetic delivery (CCLAD) systems has been developed to control the flow rate of the anesthetic solution injected through the needle. The aim of the present research is to evaluate and compare the discomfort felt by patients using a traditional syringe and the CCLAD system SleeperOne®, by considering pain, size sensation, bitterness, and vomit. 30 patients were included in the study and randomly assigned to traditional anesthesia or CCLAD. After injection, patients were assessed for the abovementioned outcomes. A Visual Analogue Scale (VAS) from 0 to 10 scores was used. As far as pain is concerned, statistically lower mean values were found in the Trial group (p < 0.05). Instead, concerning size, bitterness and vomit perceptions, no statistically significant differences were found between the groups (p > 0.05). Linear regressions were calculated considering technique, quadrant, dental arch, tooth, dentition, sex, and age as independent variables. The technique has shown to have a significant influence on pain (p < 0.05), with lower values for SleeperOne® device. Pain resulted significantly influenced by the type of dentition (p < 0.05), with higher scores for deciduous one. Moreover, perceived pain decreased with the increase of the age of patients (p < 0.05). At last, bitterness perception scores resulted to be higher for primary first molars (p < 0.05). SleeperOne® device seems to be a valid support for the reduction of pain related to anesthetic injection, especially in children. Further studies should evaluate CCLADs' uses combined with lidocaine preanesthetic as well as with conscious sedation through nitrous oxide in order to determine possible synergistic effects between these procedures.

ObjectiveThe aim of this study was to examine the properties of fiber-reinforced composite and stainless steel twisted retainers for orthodontic retention.MethodsThree different span lengths (5.0, 8.0, and 14.0 mm) of fiber-reinforced composite were investigated. The three fiber-reinforced composite retainer groups were subdivided according to the storage condition (dry and wet), resulting in a total of six groups. Each stainless steel and fiber-reinforced composite group was comprised of six specimens. The three-point bending flexural test was conducted using a universal testing machine. ANOVA was used to assess differences in the maximum load and maximum stress according to the span length, material, and storage condition. Post-hoc comparisons were performed if necessary.ResultsThe maximum stress and maximum load were significantly (p < 0.001) associated with the span length, material, and storage condition. The significant interaction between the material and span length (p < 0.001) indicated the differential effects of the material for each span length on the maximum stress and maximum load, with the difference between materials being the highest for the maximum span length.ConclusionsOur findings suggest that fiber-reinforced composite retainers may be an effective alternative for orthodontic retention in patients with esthetic concerns or allergy to conventional stainless steel wires.

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