Effect of hyposalivation on mastication and mandibular movements during speech

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The aim of this study was to evaluate whether patients with hyposalivation present damaged mastication or mandibular movements during speech. Forty subjects composed 2 groups: control and hyposalivation. Masticatory performance was assessed with a silicon-based artificial material and a 10-sieve method. Mandibular movements during speech were observed with a 3D jaw-tracking device. Data were analyzed with Student's t-test or the Mann-Whitney method (P < 0.05). The masticatory performance (mm) of control and hyposalivation were 4.40 +/- 0.62 and 4.74 +/- 1.34, respectively. Outcomes for speech movements (mm) were as follows: maximum vertical opening amplitude (10.8 +/- 4.2; 9.9 +/- 2.7) and displacements to the right (1.0 +/- 0.8; 0.5 +/- 0.6), left (1.8 +/- 1.4; 2.3 +/- 1.2), or anterior-posterior (2.8 +/- 1.1; 2.9 +/- 1.0) for control and hyposalivation, respectively. No statistical difference was found between groups for any variable. The results indicated that hyposalivation did not affect masticatory performance or mandibular movements during speech. ClinicalTrials.gov Identifier: NCT01020084.254351356Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2005/03383-1

Occlusal force, electromyographic activity of masticatory muscles and mandibular flexure of subjects with different facial types

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Objective: The aim of this study was to evaluate whether vertical facial patterns influence maximal occlusal force (MOF), masticatory muscle electromyographic (EMG) activity, and medial mandibular flexure (MMF). Material and Methods: Seventy-eight dentate subjects were divided into 3 groups by Ricketts's analysis: brachyfacial, nnesofacial and dolychofacial. Maximum occlusal force in the molar region was bilaterally measured with a force transducer. The electromyographic activities of the masseter and anterior temporal muscles were recorded during maximal voluntary clenching. Medial mandibular flexure was calculated by subtracting the intermolar distance of maximum opening or protrusion from the distance in the rest position. The data were analyzed using ANOVA followed by Tukey's HSD test. The significance level was set at 5%. Results: Data on maximum occlusal force showed that shorter faces had higher occlusal forces (P<0.0001). Brachyfacial subjects presented higher levels of masseter electromyographic activity and medial mandibular flexure, followed by the mesofacial and dolychofacial groups. Additionally, dolychofacial subjects showed significantly lower electronnyographic temporalis activities (P<0.05). Conclusion: Within the limitations of the study, it may be concluded that maximum occlusal force, masticatory muscle activity and medial mandibular flexure were influenced by the vertical facial pattern.194343349Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [476385/2004-0

Effect of Salivary Flow Rate on Masticatory Efficiency

Purpose: Saliva is a complex secretion that plays an important role in stomatognathic system activities, and its absence may lead to damaged functions such as mastication. Thus, the aim of this study was to investigate the effect of salivary flow rate on masticatory efficiency. Materials and Methods: Sixty dentate subjects were divided into three groups (n = 20) according to salivary flow rate: control (group 1), hyposalivation (group 2), and hypersalivation (group 3). All subjects from group 2 were under dermatologic treatment and taking systemic oral isotretinoin. Subjects from groups 1 and 3 were not taking any systemic medication and hypersalivation was induced in group 3 subjects by using a 6% citric acid solution. Masticatory efficiency was evaluated using an artificial test material (Optosil) and a sieving method. Masticatory efficiency was calculated as the weight percentage of the fragmented test food that passed through the 10-mesh (2-mm aperture) sieve. Data were analyzed using analysis of variance (P < .05). Results: The masticatory efficiency values (%) under normal, hypo-, and hypersalivation were 6.40 (+/- 4.35), 7.63 (+/- 5.57), and 4.73 (+/- 4.85), respectively. However, no statistical differences were found among groups. Conclusion: Within the experimental design of this study. it could be concluded that patients with reduced or increased salivary flow do not present alterations in masticatory efficiency. Int J Prosthodont 2009;22: 168-17227th International Congress of the Italian-Academy-of-the-Prosthetic-Dentistry : NOV 21-22, 2008 : Bologna, ITALY : Italian Acad Prosthet Dentistry :22216817

Chewing side, bite force symmetry, and occlusal contact area of subjects with different facial vertical patterns

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Craniofacial dimensions influence oral functions; however, it is not known whether they are associated with function asymmetry. The objective of this study was to evaluate chewing side preference and lateral asymmetry of occlusal contact area and bite force of individuals with different craniofacial patterns. Seventy-eight dentate subjects were divided into 3 groups according to the VERT index as follows: (1) mesofacial, (2) brachyfacial and (3) dolichofacial. Chewing side preference was evaluated using jaw tracking equipment, occlusal contact area was measured by silicon registration of posterior teeth, and bite force was measured unilaterally on molar regions using 2.25 mm-thick sensors. Statistical analysis was performed using ANOVA on Ranks, Student's t-test, and Mann-Whitney tests at a 5% significance level. Mesofacial, brachyfacial, and dolichofacial subjects presented more occlusal contact area on the left side. Only dolichofacial subjects showed lateral asymmetry for bite force, presenting higher force on the left side. No statistically significant differences were found for chewing side preference among all groups. Within the limitations of this study, it can be concluded that craniofacial dimensions play a role in asymmetry of bite force. ClinicalTrials.gov ID: NCT01286363.255446452Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [476385/2004-0, 140204/2009-1

Masticatory features, EMG activity and muscle effort of subjects with different facial patterns

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)P>It has been suggested that craniofacial morphology plays an important role in masticatory function, however, there are controversies and unsolved questions that still require elucidation. The aims of this study were to evaluate masticatory performance, mandibular movement, electromyographic (EMG) activity and muscle effort of masseter and anterior temporal muscles during mastication. Seventy-eight dentate subjects were selected and divided into three groups according to vertical facial pattern: brachyfacial, mesofacial and dolichofacial. Silicon-based material was used for chewing tests. Masticatory performance was determined by a 10-sieve method, and masticatory movements during mastication were assessed using a 3D mandibular tracking device. Electromyographic activities of masseter and anterior temporal muscles were evaluated during mastication, and muscle effort was calculated by the percentage of activity required for mastication based on maximum muscle effort. Data were analysed using anova and anova on-ranks tests. Dolichofacial subjects presented significantly poorer masticatory performance (6 center dot 64 +/- 2 center dot 04; 4 center dot 33 +/- 0 center dot 70 and 3 center dot 67 +/- 0 center dot 63), slower rate of chewing (1 center dot 34 +/- 0 center dot 27, 1 center dot 18 +/- 0 center dot 22 and 1 center dot 21 +/- 0 center dot 20 cycles per second) and larger posterior displacement during mastication (6 center dot 22 +/- 2 center dot 18; 5 center dot 18 +/- 1 center dot 87 and 5 center dot 13 +/- 1 center dot 89) than meso- and brachyfacial individuals, respectively. No statistical difference was detected among groups for the other masticatory movement parameters. There was no difference in absolute EMG amplitudes of masseter and anterior temporal muscles during mastication among groups, but the relative effort of both muscles was higher in dolichofacial, followed by meso- and brachyfacial subjects (masseter: 39 center dot 34 +/- 2 center dot 25; 36 center dot 87 +/- 4 center dot 05 and 33 center dot 33 +/- 4 center dot 15; anterior temporal: 38 center dot 12 +/- 1 center dot 61; 38 center dot 20 +/- 8 center dot 01 and 35 center dot 75 +/- 2 center dot 48). It was concluded that the vertical facial pattern influences masticatory performance, mandibular movement during mastication and the effort masticatory muscles required for chewing.3711813819Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [476385/2004-0, 140204/2009-1