Human amygdala activation by the sound produced during dental treatment: A fMRI study.

During dental treatments, patients may experience negative emotions associated with the procedure. This study was conducted with the aim of using functional magnetic resonance imaging (fMRI) to visualize cerebral cortical stimulation among dental patients in response to auditory stimuli produced by ultrasonic scaling and power suction equipment. Subjects (n = 7) aged 23-35 years were recruited for this study. All were right-handed and underwent clinical pure-tone audiometry testing to reveal a normal hearing threshold below 20 dB hearing level (HL). As part of the study, subjects initially underwent a dental calculus removal treatment. During the treatment, subjects were exposed to ultrasonic auditory stimuli originating from the scaling handpiece and salivary suction instruments. After dental treatment, subjects were imaged with fMRI while being exposed to recordings of the noise from the same dental instrument so that cerebral cortical stimulation in response to aversive auditory stimulation could be observed. The independent sample confirmatory t-test was used. Subjects also showed stimulation in the amygdala and prefrontal cortex, indicating that the ultrasonic auditory stimuli elicited an unpleasant response in the subjects. Patients experienced unpleasant sensations caused by contact stimuli in the treatment procedure. In addition, this study has demonstrated that aversive auditory stimuli such as sounds from the ultrasonic scaling handpiece also cause aversive emotions. This study was indicated by observed stimulation of the auditory cortex as well as the amygdala, indicating that noise from the ultrasonic scaling handpiece was perceived as an aversive auditory stimulus by the subjects. Subjects can experience unpleasant sensations caused by the sounds from the ultrasonic scaling handpiece based on their auditory stimuli.

Association of vitamin D3 with alveolar bone regeneration in dogs.

Designed sockets prepared on the mandibles of nine Beagle dogs were divided into three groups: Calcitriol +Alloplast, Alloplast and Empty. Five of the nine dogs received Vit.D3 and calcium supplement (Vit.D/Ca group), while the other four dogs without supplements were assigned to Non-Vit.D/Ca group. After 4 weeks, the extent of vertical ridge resorption (VRR), bone density (density), new bone formation (NBF) and implant stability quotient (ISQ) were measured. Following systemic Vit.D/Ca administration, the Empty subgroup showed significant differences from the Calcitriol + Alloplast subgroup on variants NBF/Density/VRR and the Alloplast subgroup on items NBF/Density/ISQ/VRR. Alternatively, the Calcitriol + Alloplast subgroup revealed higher values of NBF/Density/ISQ (P < 0.001) and a lower VRR value (P = 0.001) than the Alloplast subgroup. Although there were no significant differences in NBF (P = 0.349), density (P = 0.796), ISQ (P = 0.577) and VRR (0.979) comparisons on alloplast treatment between the Vit.D/Ca and Non-Vit.D/Ca groups, local application with Calcitriol + Alloplast demonstrated better NBF/Density/ISQ (P = 0.02 to <0.001) effects than which of Alloplast subgroups. Consequently, the results showed that both systemic and local vitamin D3 treatment might accelerate bone regeneration in dogs. Within the using dose, systemic vitamin D3 treatment displayed a superior stimulating effect than local vitamin D3 application did.

The potential effects of cholecalciferol on bone regeneration in dogs.

OBJECTIVES: The aim of this investigation was to evaluate the potential effects of the systemically delivered combination of calcium supplementation and cholecalciferol and of the locally applied biphasic calcium alloplast on the surgically produced alveolar sockets at the early healing stage in a dog model. MATERIALS AND METHODS: The mandibular pre-molars of nine Beagle dogs were extracted first. Three months later, four standardized sockets with a 4 mm in diameter and 6 mm deep cylinder were created bilaterally at healed extraction sites. The sockets on one side were grafted with biphasic calcium phosphate alloplast, whereas the defects on the other side were left un-grafted. The dogs were then randomly divided into two groups; five dogs received oral calcium and cholecalciferol combination (Vit.D/Ca) and were assigned to the test group (Vit.D/Ca Group). The other four dogs without Vit.D/Ca supplement were distributed to the control group (Non-Vit.D/Ca Group). The bone density (Density) and the implant stability quotient (ISQ) at prepared sites were measured 4 weeks later. The drawn bone cores were examined by a histomorphometric analysis for measurement of new bone formation (NBF). The amount of vertical ridge resorption (VRR) was evaluated. RESULTS: The Vit.D/Ca-treated subjects revealed significantly more NBF (P < 0.05), higher bone density (P < 0.05) and significantly less vertical ridge reduction (P < 0.05) in the healing sockets than those without Vit.D/Ca treatment. The non-grafted sockets demonstrated significantly more NBF (P < 0.05), higher bone density (P < 0.05), better ISQ value (P < 0.05) and more vertical ridge reduction (P < 0.05) than those in the grafted sockets. There was no significant difference between the serum data determined before and 4 weeks after experiment in Vit.D/Ca Group or Non-Vit.D/Ca Group. However, the changed value (post-op vs. pre-op) between the two groups was significant in the serum level of phosphate and parathyroid hormone (P = 0.05). CONCLUSION: The results of the present study indicated that the examined calcium phosphate alloplast may perform a function in alveolar ridge preservation while reducing the potential of NBF potential in the healing extraction socket. Also, the combination of calcium supplementation and cholecalciferol may have systemic effects on accelerating bone regeneration.