Mandibular advancement and morphological changes in the mandibles of female mice of different ages.
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 1mm 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.
Tagliaro
Maria Luisa
ML
Biomedical Gerontology Post-graduate Program, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre 90035-051, Brazil. mltagliaro@terra.com.br
Rassi Guimarães
Maria Leticia
ML
Pereira Padilha
Dalva Maria
DM
Callegari-Jacques
Sidia Maria
SM
Jeckel-Neto
Emilio Antônio
EA
D000375:Aging / Q000502:physiology*; D000818:Animals; D001835:Body Weight / Q000502:physiology; D002508:Cephalometry / Q000379:methods; D005260:Female; D008334:Mandible / Q000033:anatomy & histology / Q000254:growth & development / Q000502:physiology*; D019186:Mandibular Advancement / Q000379:methods*; D008335:Mandibular Condyle / Q000648:ultrastructure; D051379:Mice; D008855:Microscopy, Electron, Scanning / Q000379:methods