RESUMEN
Few studies of dentofacial and orthodontic structural relationships relative to temporomandibular joint (TMJ) dysfunction have been reported. We undertook this investigation to determine any correlation of orthodontic and dentofacial characteristics with TMJ bilateral disc displacement. The population of patients was selected from a TMJ clinic where a control group of asymptomatic volunteers had been previously established and standardized. Differences in skeletal structural features were determined among three study groups: (1) asymptomatic volunteers with no TMJ disk displacement, (2) symptomatic patients with no TMJ disc displacement, and (3) symptomatic patients with bilateral TMJ disk displacement. Thirty-two asymptomatic volunteers without disk displacement (25 female, 7 male) were compared with the same number each of symptomatic patients without TMJ disk displacement and symptomatic patients with bilateral TMJ disk displacement. All subjects had undergone a standardized clinical examination, bilateral TMJ magnetic resonance imaging, and lateral cephalometric radiographic analysis. The groups were matched according to sex, TMJ status, age, and Angle classification of malocclusion. Seventeen lateral cephalometric radiographic cranial base, maxillomandibular, and vertical dimension variables were evaluated and compared among the study groups. The mean angle of SNB, or the intersection of the sella-nasion plane and the nasion-point B line (indicating mandibular retrognathism relative to cranial base), of the symptomatic patients-with-displacement group was significantly smaller than that in the asymptomatic volunteers and symptomatic patients without bilateral disk displacement (p < 0.05). Female subjects showed smaller linear measurements of mandibular length, lower facial height, and total anterior facial height than male subjects in all three groups (p < 0.05). The mean angle of ANB, or the intersection of the nasion-point A and nasion-point B planes (indicating retrognathism of mandible relative to maxilla), was significantly greater in female than in male subjects, in all groups (p < 0.05). Symptomatic patients with bilateral disk displacement had a retropositioned mandible, indicated by a smaller mean SNB angle compared with that in asymptomatic volunteers and symptomatic patients with no disk displacement on either side. Lateral cephalometric radiographic assessment may improve predictability of TMJ disk displacement in orthodontic patients but is not diagnostic; nor does the assessment explain any cause-and-effect relationship.
Asunto(s)
Cefalometría , Luxaciones Articulares/diagnóstico por imagen , Trastornos de la Articulación Temporomandibular/diagnóstico por imagen , Adulto , Análisis de Varianza , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Mandíbula/diagnóstico por imagen , Maxilar/diagnóstico por imagen , Valor Predictivo de las Pruebas , Radiografía , Retrognatismo/diagnóstico por imagen , Estudios Retrospectivos , Caracteres Sexuales , Base del Cráneo/diagnóstico por imagen , Estadísticas no Paramétricas , Disco de la Articulación Temporomandibular/diagnóstico por imagen , Dimensión VerticalAsunto(s)
Certificación , Ortodoncia , Ortodoncia/educación , Consejos de Especialidades , Estados UnidosRESUMEN
An extensive literature review and two-year evaluation of the stability of surgical mandibular advancement, using implants in proximal and distal segments. Regression averaged 27% of the initial correction, with most occurring early.
Asunto(s)
Ortodoncia Correctiva , Retrognatismo/cirugía , Adolescente , Adulto , Cefalometría , Femenino , Humanos , Masculino , Mandíbula/anatomía & histología , Mandíbula/cirugía , Cóndilo Mandibular/anatomía & histología , Osteotomía/métodos , Prótesis e Implantes , Recurrencia , Retrognatismo/terapiaRESUMEN
With the increased amount of orthognathic surgery being performed by orthodontists and oral-maxillofacial surgeons, more efficient treatment techniques are being perfected. Modular intermaxillary fixation has been developed to help the orthodontist prepare his patient for surgery and provide the surgeon with the stable fixation needed for proper healing. It is efficient, saves chair time, is comfortable and esthetic, and is well accepted by patients. Modular intermaxillary fixation has been evaluated for more than a year, with good results in correcting mandibular skeletal dysplasias in all three planes of space.