Mandibular advancement and morphological changes in the mandibles of female mice of different ages

• Published in: Experimental gerontology Vol. 41; no. 11; pp. 1157 - 1164
• Main Authors: Tagliaro, Maria Luisa, Rassi Guimarães, Maria Leticia, Pereira Padilha, Dalva Maria, Callegari-Jacques, Sidia Maria, Jeckel-Neto, Emilio Antônio
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 01.11.2006
• Subjects: Aging; Aging - physiology; Animals; Body Weight - physiology; Cephalometry - methods; Female; Functional Maxillary Orthopedics; Functional orthopedics appliance; Mandible - anatomy & histology; Mandible - growth & development; Mandible - physiology; Mandibular advancement; Mandibular Advancement - methods; Mandibular condyle; Mandibular Condyle - ultrastructure; Mandibular growth; Mandibular measurements; Mandibular protrusion; Mice; Microscopy, Electron, Scanning - methods; Temporomandibular joint; Mandibular advancement; Mandibular measurements; Aging; Temporomandibular joint; Functional orthopedics appliance; Mandibular condyle; Functional Maxillary Orthopedics; Mandibular growth; Mandibular protrusion
• ISSN: 0531-5565; 1873-6815
• DOI: 10.1016/j.exger.2006.08.001

Mandibular advancement (MA) by means of functional orthopedic techniques is currently used in young patients to stimulate mandibular growth. The aim of this study was to evaluate the morphological changes in the mandibles of 2-, 7-, and 16-month-old female mice after MA. Every 3 days during 1 month, the lower incisors were trimmed by 1 mm to induce protrusion when the animal was feeding. The left mandibles of the 30 experimental and 28 control individuals were subsequently dissected and digital images were obtained to analyze nine linear/angular measurements. The condylar microstructure was also analyzed by scanning electron microscopy (SEM). The linear/angular measurements showed a growth response in different mandibular regions in 2- and 16-month-old individuals. SEM showed that, in the 7-month-old mice, the condylar cartilage had regenerated in the treated individuals but not in the controls. The results suggest that MA produces mandibular growth in 2- and 16-month-old female mice. Although there was no mandibular growth in 7-month-old mice, regeneration of the condylar cartilage was detected, thus demonstrating that different responses to the MA stimulus occur in female mice of different ages.