RESUMEN
Oral appliances have been a popular treatment option for subjects with obstructive sleep apnea. However, little information is available on how brain activation induced by respiratory challenge is modulated by mandibular advancement with these appliances. We hypothesized that the brain activation caused by respiratory stress may be alleviated by mandibular advancement. Respiratory stress was induced in 12 healthy subjects by resistive inspiratory loading. The effects of mandibular advancement during resistive inspiratory loading were assessed subjectively by using a visual analog scale. These effects were also evaluated objectively by using blood oxygenation level-dependent functional magnetic resonance imaging. The score for the visual analog scale significantly decreased with mandibular advancement. Cortical deactivation, in association with mandibular advancement, was localized to several specific regions, including the left cingulate gyrus and the bilateral prefrontal cortexes. These regions are known to be involved in respiratory control. Our results suggest that mandibular advancement with an oral appliance appears to be useful for reducing respiratory stress, based on both subjective and neuronal criteria.
Asunto(s)
Mapeo Encefálico , Encéfalo/fisiología , Disnea/prevención & control , Inhalación/fisiología , Avance Mandibular , Adulto , Disnea/sangre , Disnea/fisiopatología , Giro del Cíngulo/fisiología , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Avance Mandibular/instrumentación , Oxígeno/sangre , Dimensión del Dolor , Corteza Prefrontal/fisiología , Centro Respiratorio/fisiologíaRESUMEN
AIM: To evaluate changes in stomatognathic function related to orthodontic treatment in 4 patients with various types of dysfunction of the stomatognathic system present prior to orthodontic treatment. METHODS: Four patients who visited the Orthodontic Clinic at Tokyo Medical and Dental University Hospital and whose active orthodontic treatment was complete were analyzed both morphologically and functionally. To analyze stomatognathic function, electromyographic activity of the masticatory muscles and mandibular movements was recorded. RESULTS: In all 4 patients, changes in stomatognathic function were observed following improvements in craniofacial structural and interocclusal relationships. Many of these changes consisted of elimination of functional disharmony, although the cause-effect relationship between these functional changes and orthodontic treatment is unclear. CONCLUSION: Functional analysis during orthodontic treatment can provide useful information concerning the relationship between craniofacial structures and stomatognathic function.
Asunto(s)
Maloclusión/terapia , Músculos Masticadores/fisiología , Ortodoncia Correctiva , Retrognatismo/terapia , Trastornos de la Articulación Temporomandibular/terapia , Adulto , Cefalometría , Niño , Oclusión Dental Céntrica , Electromiografía , Femenino , Humanos , Masculino , Mandíbula/fisiología , Avance Mandibular , Retrognatismo/cirugíaRESUMEN
AIMS: To examine differences in the craniofacial morphology of skeletal Class III patients before treatment and growth-related changes during treatment with a maxillary protraction appliance (MPA) between patients who were treated only orthodontically (orthodontic group) and those who eventually received orthognathic surgery (surgical group). METHODS: The orthodontic and surgical groups consisted of 6 boys and 9 girls and 4 boys and 6 girls, respectively. Lateral cephalograms taken at the first visit and at the end of treatment with the MPA were measured. The Mann-Whitney U test and Wilcoxon signed-rank test were used. RESULTS: Before treatment, the Wits appraisal was significantly smaller and the gonial angle was significantly larger in the surgical group. During treatment, both the SNA and ANB angles were significantly increased in the orthodontic group, whereas only the SNB angle was significantly increased in the surgical group. Moreover, significant lingual inclination of the mandibular incisors was found in the orthodontic group. CONCLUSION: The Wits appraisal and gonial angle were useful for distinguishing between the two groups at the first visit. Facilitation of forward maxillary growth, modification of the direction of mandibular growth, and lingual tipping of the mandibular incisors may be important ways to avoid orthognathic surgery.
Asunto(s)
Aparatos de Tracción Extraoral , Huesos Faciales/patología , Maloclusión de Angle Clase III/terapia , Cráneo/patología , Cefalometría , Niño , Huesos Faciales/crecimiento & desarrollo , Femenino , Estudios de Seguimiento , Humanos , Incisivo/patología , Masculino , Maloclusión de Angle Clase III/patología , Maloclusión de Angle Clase III/cirugía , Mandíbula/crecimiento & desarrollo , Mandíbula/patología , Maxilar/crecimiento & desarrollo , Maxilar/patología , Diente Molar/patología , Cráneo/crecimiento & desarrollo , Técnicas de Movimiento DentalRESUMEN
Initial mandibular position might be a key factor leading to rapid therapeutic outcome in oral appliance therapy for patients with obstructive sleep apnea (OSA). The purpose of this study was to investigate the effects of an adjustable oral appliance on nasal resistance in 7 nonapneic patients. Upright and supine nasal resistance was measured for each subject with an adjustable oral appliance in place in 3 mandibular positions: most retruded (MAX0), maximum protrusion (MAX100), and 67% of MAX100 (MAX67). A significant decrease in upright and supine nasal resistance was observed between MAX0 and MAX67 (P < .01), and between MAX0 and MAX100 (P < .01), but not between MAX67 and MAX100. In addition, there was a positive correlation between the nasal resistance at MAX0 and the nasal resistance change from MAX0 to MAX67 (P < .01), indicating that when the mandible was advanced from MAX0 to MAX67, the more nasal resistance at MAX0, the greater the reduction in nasal resistance at MAX67. These findings suggest that MAX67 might be indicated as the initial mandibular position and that gradual anterior titration of mandibular position beyond MAX67 would give OSA patients rapid therapeutic effects by reducing the nasal resistance. Moreover, OSA patients with augmented nasal resistance at MAX0 might have a greater reduction in nasal resistance in response to MAX67 in oral appliance therapy.
Asunto(s)
Resistencia de las Vías Respiratorias/fisiología , Mandíbula/anatomía & histología , Avance Mandibular/instrumentación , Nariz/fisiología , Adulto , Índice de Masa Corporal , Humanos , Masculino , Paladar Blando/anatomía & histología , Faringe/anatomía & histología , Postura/fisiología , Rinomanometría , Posición Supina/fisiologíaRESUMEN
STUDY OBJECTIVES: To examine changes in the upper-airway dimension and its surrounding structures induced by mandibular advancement during sleep. DESIGN: Eleven nonapneic adult males participated in the study. A set of supine lateral cephalograms was taken for each subject at the end of expiration during stage 1 and 2 non-rapid-eye-movement sleep with and without a Klearway appliance (Great Lakes Orthodontics, NY, USA), which was adjusted to 67% of the maximum protrusion position. The Wilcoxon signed-rank test was used to compare changes in the anteroposterior width of the upper airway and the positions of the hyoid bone and third cervical vertebra with and without the appliance. SETTING: N/A. PATIENTS OR PARTICIPANTS: N/A. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: The amount of jaw opening was significantly increased by wearing the titratable oral appliance, and the mandibular symphysis moved backward. The sagittal dimension of the superior pharyngeal airway was significantly increased; however, no significant changes were found in the middle and inferior pharyngeal airway. Significant posterior displacement of the hyoid bone and third cervical vertebra was seen. Moreover, significant inferior displacement of the hyoid bone was also seen. The relationship among the mandibular symphysis, the hyoid bone, and the third cervical vertebra remained constant. CONCLUSIONS: Mandibular advancement significantly increases the size of the upper airway in the velopharynx and results in posteroinferior displacement of the hyoid bone and posterior displacement of the third cervical vertebra during sleep.
Asunto(s)
Obstrucción de las Vías Aéreas/prevención & control , Avance Mandibular/métodos , Sueño , Posición Supina , Adulto , Índice de Masa Corporal , Humanos , Masculino , Ventilación Pulmonar , Fases del Sueño/fisiologíaRESUMEN
The effect of nasal obstruction on nocturnal masseter and suprahyoid muscle activities using a newly developed portable electromygram (EMG)-recording unit was examined. Ten healthy Japanese males participated in this study. EMG activities of both the right masseter and bilateral suprahyoid muscles were recorded with a portable EMG-recording unit. At midnight, the subject was asked to lie on a bed after complete preparation with surface electrodes. After maximal clenching and jaw-opening effort (100% maximum voluntary contribution), the subject was allowed to fall asleep. In the first half of the night, EMG activities were recorded for about three hours of sleep without nasal obstruction. In the second half of the night, EMG activities were recorded for about three hours of sleep with nasal obstruction. In both muscles, there were no significant changes in either the maximal EMG activities or the number of events beyond 40% MVC with nasal obstruction. But in an evaluation based on the distribution of muscle activities, the EMG activity of the masseter muscle tended to decrease (P = .07) and that of the suprahyoid muscles increased significantly (P = .02) with nasal obstruction. These results suggest that nasal obstruction could modulate the activities of the masseter and suprahyoid muscles during sleep.
Asunto(s)
Músculo Masetero/fisiopatología , Obstrucción Nasal/fisiopatología , Músculos del Cuello/fisiopatología , Sueño/fisiología , Adulto , Electromiografía , Humanos , Masculino , Mandíbula/fisiopatología , Movimiento , Contracción Muscular/fisiología , Procesamiento de Señales Asistido por Computador , Estadísticas no Paramétricas , Factores de TiempoRESUMEN
OBJECTIVE: To present a case of hemimandibular hyperplasia (HH) treated with orthognathic surgery that preserves the condyle without disturbing mandibular function. METHODS: A 27-year-old woman with HH was treated with orthognathic surgery preserving the enlarged condylar head. Radiographic examination showed typical enlargement of the right condyle, elongation of the right ascending ramus and mandibular body, and tilted occlusal plane. A mandibular sagittal split osteotomy on the unaffected side and subcondylar ramus osteotomy on the affected side, Le Fort I wedge osteotomy to relevel the tilted occlusal plane, and contouring of the lower mandibular margin were performed. RESULTS: Excellent results in the full-face appearance and occlusion were obtained. There was no change in the size of the reserved condylar head 4 years postoperatively. In a series of examinations of jaw function with electromyography, mandibular kinesiography, and computer-aided diagnostic axiography, more favorable findings were obtained postoperatively. CONCLUSIONS: In a case of HH without abnormally high growth activity, orthognathic surgery preserving hypertrophic condyle produced functional improvement in addition to good occlusal and aesthetic outcomes.
Asunto(s)
Asimetría Facial/cirugía , Mandíbula/patología , Cóndilo Mandibular/patología , Adulto , Oclusión Dental , Diagnóstico por Computador , Electromiografía , Estética Dental , Femenino , Estudios de Seguimiento , Humanos , Hiperplasia , Registro de la Relación Maxilomandibular/métodos , Maloclusión/cirugía , Mandíbula/fisiopatología , Mandíbula/cirugía , Cóndilo Mandibular/fisiopatología , Cóndilo Mandibular/cirugía , Movimiento , Osteotomía/clasificación , Osteotomía/métodos , Osteotomía Le FortRESUMEN
The purpose of this retrospective study was to compare 2-dimensionally the sizes of the adenoidal tissues and the upper airways in juvenile and adolescent males with and without cleft lip and palate (CLP). Two paired groups of age-matched boys were used: (1) 90 juveniles with CLP (CLP/j) and without CLP (control/j) and (2) 40 adolescents with CLP (CLP/a) and without CLP (control/a). Measurements of adenoidal tissues and upper airways were determined by using lateral cephalograms. The adenoidal tissue was significantly larger in the CLP/j group than in the control/j group, but there was no significant difference between the CLP/a and control/a groups. The adenoidal tissue was significantly smaller in the CLP/a group than in the CLP/j group. The upper airway in the CLP/j group was significantly smaller than that in the control/j group, and that in the CLP/a group was also significantly smaller than that in the control/a group. Moreover, the upper airway in the CLP/a group was significantly larger than that in the CLP/j group, and that in the control/a group was significantly larger than that in the control/j group. However, the upper airway in the CLP/a group was significantly smaller than that in the control/a group. These results suggest that the larger adenoidal tissues in the CLP/j group, compared with those in the control/j group, decreased to a similar size with aging. However, the more restricted upper airway in the CLP/j group, compared with that in the control/j group, appeared to persist until adolescence.
Asunto(s)
Tonsila Faríngea/patología , Fisura del Paladar/patología , Desarrollo Maxilofacial , Nasofaringe/patología , Adolescente , Análisis de Varianza , Estudios de Casos y Controles , Cefalometría , Niño , Labio Leporino/patología , Humanos , Masculino , Estudios Retrospectivos , Estadísticas no ParamétricasRESUMEN
This study was conducted to examine the effect of treatment with a maxillary protraction appliance on the development of the craniofacial structures and upper-airway dimensions. A total of 25 patients (mean age: 9.8 years) with Class III malocclusions were evaluated by the use of lateral cephalograms. A significant increase in maxillary forward growth, inhibition of mandibular forward growth, and clockwise rotation of the mandible were observed. The maxillary incisors were significantly proclined and the mandibular incisors significantly retroclined. A multiple-regression analysis revealed that maxillary growth had a significant positive effect on the superior upper-airway dimension. These findings indicate that the superior upper-airway dimension can be altered during maxillary protraction.
Asunto(s)
Aparatos de Tracción Extraoral , Maloclusión de Angle Clase III/patología , Maxilar/crecimiento & desarrollo , Faringe/anatomía & histología , Cefalometría , Niño , Femenino , Humanos , Masculino , Maloclusión de Angle Clase III/terapia , Desarrollo Maxilofacial , Análisis de RegresiónRESUMEN
The purpose of this study was to examine the effect of a bionator on masseter and suprahyoid muscle activities during sleep. Ten healthy Japanese males (mean age: 26.3 years) participated in this study. Electromyographic (EMG) activities of the right masseter and bilateral suprahyoid muscles were recorded during sleep with and without a bionator. Although no significant changes were observed in the maximal EMG activities of these muscles, the maximal EMG activity of suprahyoid muscles tended to decrease while wearing the bionator. The number of events over 40% maximal voluntary contraction (MVC) tended to decrease in these muscles with a bionator, but these changes were not statistically significant. These findings indicate that there are no significant changes or there is only a tendency to decrease the activities of the masseter and suprahyoid muscles while wearing a bionator during sleep.
Asunto(s)
Aparatos Activadores , Músculo Masetero/fisiología , Músculos del Cuello/fisiología , Sueño/fisiología , Adulto , Electromiografía , Humanos , Masculino , Contracción Muscular , Estadísticas no ParamétricasRESUMEN
Previous reports have indicated that formation and eruption of the maxillary teeth, especially the molars, are delayed in skeletal Class III patients compared with Class I and Class II patients. However, the relationship between the formation/eruption of maxillary teeth and the skeletal pattern of the maxilla is not yet clear. To examine this relationship, we studied 81 skeletal Class III Japanese patients (mean age, 8.8 years). The sample was divided into 2 groups: a maxillary retrusion (MR) group, characterized by a small SNA angle and a short palatal length, and a control group in which those values were in the normal range for patients of Japanese descent. There was no significant difference in the rate of formation for the maxillary and mandibular teeth between the 2 groups. The eruption of the maxillary second molars was delayed in the MR group compared with the control group. There were no significant differences between the 2 groups for any other teeth. A multiple-regression analysis was carried out to examine whether the skeletal pattern of the maxilla is a useful indicator for predicting the eruption of the maxillary teeth. The results showed that palatal length and chronologic age were significant independent (explanatory) variables for predicting eruption of the maxillary second molars. These findings indicated that the skeletal pattern of the maxilla is a useful indicator for predicting the timing of maxillary molar eruption when considering treatment of skeletal Class III malocclusions.
Asunto(s)
Maloclusión de Angle Clase III/fisiopatología , Maxilar/patología , Erupción Dental , Factores de Edad , Estudios de Casos y Controles , Cefalometría , Niño , Femenino , Humanos , Japón , Masculino , Diente Molar/fisiopatología , Odontogénesis , Análisis de Regresión , Retrognatismo/fisiopatología , Estadísticas no ParamétricasRESUMEN
The purpose of this study was to examine the changes in nasal patency induced by forward mandibular displacement or changes in body posture. Fifteen healthy adults participated in this study. To examine the influence of mandibular position, nasal resistance was recorded in intercuspal, middle, and maximum forward positions. To evaluate the effect of body posture, nasal resistance was recorded in the four postures of sitting erect, 30 degrees and 60 degrees dorsally reclined, and supine. The nasal patencies recorded in the middle and maximum forward mandibular positions were significantly higher than those recorded in the intercuspal position. Regarding the effect of body posture, the nasal patency showed a progressive decrease from the sitting erect position to the supine position. These results suggest that changes in mandibular position and body posture significantly affect nasal patency and that mandibular position and body posture should be considered basic information in the treatment of obstructive sleep apnea.