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Mastication Time (mastication + time)
Selected AbstractsValidation of video versus electromyography for chewing evaluation of the elderly wearing a complete dentureJOURNAL OF ORAL REHABILITATION, Issue 8 2007E. NICOLAS summary, Chewing efficiency may affect nutritional status in the elderly. Many elderly patients are complete denture wearers, and often present cognitive problems. Those two factors make evaluation of mastication difficult with experimental methods. Analysis of video recording may be a simple way to routinely assess chewing parameters. This study aimed at validating several parameters of video evaluation versus electromyography (EMG), which is considered the ,gold standard'. The design was a prospective randomized study, carried out at the Faculty of Dentistry, University of Auvergne, Clermont-Ferrand, France. Twelve complete denture wearers chewed four model foods differing in hardness. Sessions were videotaped and EMG recordings were registered. Mastication time, number of masticatory cycles and cleaning time were recorded simultaneously by video and EMG. Two investigators independently analyzed the videos twice, in random order. Evaluation of criterion validity: a positive video/EMG correlation was found for the parameters ,chewing time' (0·89, Pearson) and ,number of masticatory cycles' (0·94, Spearman), whereas no statistical difference was found between these two EMG and video variables (t -test). Inter and intra-rater reliability gave a positive intraclass coefficient (ICC) for duration of mastication (0·86,0·98), number of masticatory cycles (0·90,0·97) and cleaning time (0·90,0·98). Discriminatory ability was studied using anova (P = 0·01): variation was significant in masticatory duration (F = 10), number of masticatory cycles (F = 10) and cleaning time (F = 4). Video may be a useful assessment tool in prosthetic rehabilitation and can be applied to help choose the type of food (solid, semi-liquid or liquid) to administer to dependent persons, particularly those suffering from dementia. [source] Analysis of Masticatory Cycle Efficiency in Complete Denture WearersJOURNAL OF PROSTHODONTICS, Issue 1 2010Marcelo Coelho Goiato DDS Abstract Purpose: This study assessed masticatory efficiency and duration of the masticatory cycle in 14 asymptomatic patients with severe bone resorption. All patients had worn complete dentures for over 10 years. Recall visits were scheduled at 5 months and 1 year after receiving new dentures. Materials and Methods: Fourteen patients were evaluated in this study. The Research Diagnostic Criteria questionnaire and tests of the efficiency and duration of the masticatory cycle were performed with artificial food before, 5 months after, and 1 year after new dentures were delivered. Masticatory efficiency was assessed using a sieve system; artificial food was ground for 35 masticatory cycles and monitored by the operator. Results: Masticatory efficiency at 5 months was significantly improved for the 0.42-mm mesh. An improvement in masticatory efficiency and a reduction in mastication time were observed with the new dentures after 1 year. Conclusion: The results of this study indicated that 5 months did not allow enough time to demonstrate improved muscular capacity and ability after receiving new dentures. After 1 year, the duration of the masticatory cycle was reduced, and masticatory efficiency was significantly improved. [source] Mechanochemical copolymerization of poly(vinyl chloride) with methyl methylacrylate in an open mill machineJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2006Peixin He Mechanical degradation of poly(vinyl chloride) (PVC) and mechanochemical copolymerization in poly(vinyl chloride)/methyl methylacrylate (PVC/MMA) systems were studied in an open mill machine. The effects of the mastication temperature, mastication time, and additives (oxygen, THF, or hydroquinone) on the mechanical degradation of PVC were investigated. The molecular weight of PVC decreased with increasing mastication time, and the efficiency of the mechanodegradation of PVC was lowered with increasing mastication temperature. The effects of the ratio of PVC to MMA, thin-passage time, and initiator on mechanochemical copolymerization also were studied. The experimental results indicated that the degree of copolymerization increased with increasing thin-passage times up to 45 times and then remained constant. There was a maximum degree of copolymerization at a ratio of 0.22 g/mL (PVC/MMA), and the efficiency of copolymerization always decreased with increasing time. The maximum degree and efficiency of copolymerization were 5.8 and 89%, respectively. The poly(vinyl chloride- co -methyl methylacrylate) copolymer can further improve the interfacial adhesion of PVC and PMMA. Thus it improves the mechanical properties of the PVC/CPE blend more effectively than pure PMMA. J. VINYL. ADDIT. TECHNOL. 12:42,48, 2006. © 2006 Society of Plastics Engineers. [source] | ||||||||||