scholarly journals Mandibular Movement and Masticatory Efficiency When Compared between the Two Most Representative Patterns of Masticatory Path.

2000 ◽  
Vol 44 (1) ◽  
pp. 147-155
Author(s):  
Yukinori Iwanami ◽  
Hiroshi Shiga ◽  
Yoshinori Kobayashi
PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2132 ◽  
Author(s):  
Frank J. Varriale

Extensive oral processing of food through dental occlusion and orbital mandibular movement is often cited as a uniquely mammalian trait that contributed to their evolutionary success. Save for mandibular translation, these adaptations are not seen in extant archosaurs or lepidosaurs. In contrast, some ornithischian dinosaurs show evidence of precise dental occlusion, habitual intraoral trituration and complex jaw motion. To date, however, a robust understanding of the diversity of jaw mechanics within non-avian dinosaurs, and its comparison with other vertebrates, remains unrealized. Large dental batteries, well-developed dental wear facets, and robust jaws suggests that neoceratopsian (horned) dinosaurs were capable chewers. But, biomechanical analyses have assumed a relatively simple, scissor-like (orthal) jaw mechanism for these animals. New analyses of dental microwear, presented here, show curvilinear striations on the teeth ofLeptoceratops. These features indicate a rostral to caudal orbital motion of the mandible during chewing. A rostrocaudal mandibular orbit is seen in multituberculates, haramiyid allotherians, and some rodents, and its identification inLeptoceratops gracilisis the first evidence of complex, mammal-like chewing in a ceratopsian dinosaur. The term circumpalinal is here proposed to distinguish this new style of chewing from other models of ceratopsian mastication that also involve a palinal component. This previously unrecognized complexity in dinosaurian jaw mechanics indicates that some neoceratopsian dinosaurs achieved a mammalian level of masticatory efficiency through novel adaptive solutions.


1999 ◽  
Vol 81 (6) ◽  
pp. 704-709 ◽  
Author(s):  
D. Compagnon ◽  
J.L. Veyrune ◽  
M. Morenas ◽  
D. Faulks

2008 ◽  
Vol 38 (11-12) ◽  
pp. 1152-1162 ◽  
Author(s):  
Jing-Jing Fang ◽  
Tai-Hong Kuo
Keyword(s):  

2014 ◽  
Vol 19 (1) ◽  
pp. 46-54 ◽  
Author(s):  
Fabio de Abreu Vigorito ◽  
Gladys Cristina Dominguez ◽  
Luís Antônio de Arruda Aidar

OBJECTIVE: To assess the dentoskeletal changes observed in treatment of Class II, division 1 malocclusion patients with mandibular retrognathism. Treatment was performed with the Herbst orthopedic appliance during 13 months (phase I) and pre-adjusted orthodontic fixed appliance (phase II). METHODS: Lateral cephalograms of 17 adolescents were taken in phase I onset (T1) and completion (T2); in the first thirteen months of phase II (T3) and in phase II completion (T4). Differences among the cephalometric variables were statistically analyzed (Bonferroni variance and multiple comparisons). RESULTS: From T1 to T4, 42% of overall maxillary growth was observed between T1 and T2 (P < 0.01), 40.3% between T2 and T3 (P < 0.05) and 17.7% between T3 and T4 (n.s.). As for overall mandibular movement, 48.2% was observed between T1 and T2 (P < 0.001) and 51.8% between T2 and T4 (P < 0.01) of which 15.1% was observed between T2 and T3 (n.s.) and 36.7% between T3 and T4 (P < 0.01). Class II molar relationship and overjet were properly corrected. The occlusal plane which rotated clockwise between T1 and T2, returned to its initial position between T2 and T3 remaining stable until T4. The mandibular plane inclination did not change at any time during treatment. CONCLUSION: Mandibular growth was significantly greater in comparison to maxillary, allowing sagittal maxillomandibular adjustment. The dentoalveolar changes (upper molar) that overcorrected the malocclusion in phase I, partially recurred in phase II, but did not hinder correction of the malocclusion. Facial type was preserved.


2004 ◽  
Vol 12 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Leonardo Rigoldi Bonjardim ◽  
Maria Beatriz Duarte Gavião ◽  
Luciano José Pereira ◽  
Paula Midori Castelo

This research aimed to evaluate mandibular movements in children with and without signs and symptoms of temporomandibular dysfunction. The sample taken consisted of 99 children aged 3 to 5 years distributed in two groups: I - Absence of signs and/or symptoms of TMD (25 girls/40 boys); II - Presence of signs and symptoms of TMD (16 girls/18 boys). The symptoms were evaluated through an anamnesis questionnaire answered by the child's parents/caretakers. The clinical signs were evaluated through intra- and extraoral examination. Maximum mouth opening and left/right lateral movements were measured using a digital caliper. The maximum protrusive movement was measured using a millimeter ruler. The means and standard deviations for maximum mouth opening in Group I and Group II were 40.82mm±4.18 and 40.46mm±6.66, respectively. The values found for the left lateral movement were 6.96mm±1.66 for Group I and 6.74mm±1.55 for Group II, while for the right lateral movement they were 6.46mm±1.53 and 6.74mm±1.77. The maximum protrusion movements were 5.67mm±1.76 and 6.12mm±1.92, in Groups I and II, respectively. The mandibular movement ranges neither differed statistically between groups nor between genders. FAPESP Process 96/0714-6.


1984 ◽  
Vol 11 (2) ◽  
pp. 103-109 ◽  
Author(s):  
K. D. B. FAULKNER ◽  
H. F. ATKINSON
Keyword(s):  

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