RESUMEN
This study tested the hypothesis that denture instability limits the amount of voluntary muscular effort generated by denture wearers. Seventeen edentulous subjects (seven men, 10 women; mean age 60·3 ± 13·0 years) with newly acquired implant-retained mandibular overdentures and a conventional maxillary denture participated. Maximum bite forces and corresponding electromyographic (EMG) activity from the temporalis and masseter muscles (bilaterally) were recorded under two experimental conditions: (i) Unilateral premolar and molar bites without additional support, and (ii) premolar and molar bites with bite block support on the opposite side. In addition, EMG values alone were recorded during maximum clenching without any transducer between the upper and lower dentures. The level of muscular effort was significantly higher with greater denture support. These results indicate that denture instability probably prevents denture wearers from using the full potential of their jaw muscles, especially during unilateral biting and chewing, even with two implants supporting the mandibular dentures.
Asunto(s)
Fuerza de la Mordida , Retención de Dentadura , Dentadura Completa Superior , Prótesis de Recubrimiento , Músculo Masetero/fisiopatología , Músculo Temporal/fisiopatología , Anciano , Análisis de Varianza , Prótesis Dental de Soporte Implantado , Análisis del Estrés Dental , Electromiografía , Femenino , Humanos , Masculino , Mandíbula , Persona de Mediana Edad , Boca Edéntula/fisiopatología , Ferulas Oclusales , TransductoresRESUMEN
Although it is well known that conventional denture wearers have lower maximum bite forces than dentate subjects, no previous studies have compared the strength of the jaw muscles between these two groups. This study compared maximum bite forces, electromyographic (EMG) activity and estimated jaw muscle strength among three groups: (i) 17 edentulous subjects using newly acquired implant-retained overdentures (seven men, 10 women; mean age 60.3 +/- 13.0 years); (ii) 10 age-matched, fully dentate subjects (five men, five women; mean age 57.9 +/- 11.0 years); and (iii) 39 young, fully dentate subjects (19 men, 20 women; mean age 24.4 +/- 3.5 years). Electromyographic activity was recorded from subjects' bilateral superficial masseter and anterior temporalis muscles while they generated maximum voluntary bite forces at the right central incisor, right first premolar and right first molar positions. Jaw muscle strength was estimated as the ratio of average EMG activity for all four muscles to the maximum bite force. At all three bite positions, edentulous subjects produced maximum bite forces that were less than half that of dentate subjects. Edentulous subjects also produced significantly less EMG activity and had significantly lower estimated jaw muscle strength. Our results suggest that weakened jaw muscles are one factor contributing to lower maximum bite forces among users of conventional dentures.
Asunto(s)
Fuerza de la Mordida , Retención de Dentadura/efectos adversos , Prótesis de Recubrimiento/efectos adversos , Músculos Masticadores/fisiopatología , Debilidad Muscular/etiología , Adulto , Anciano , Estudios de Casos y Controles , Implantes Dentales , Prótesis Dental de Soporte Implantado/efectos adversos , Electromiografía , Femenino , Humanos , Arcada Edéntula/fisiopatología , Arcada Edéntula/rehabilitación , Masculino , Mandíbula , Músculos Masticadores/fisiología , Análisis por Apareamiento , Persona de Mediana Edad , Fuerza Muscular , Debilidad Muscular/fisiopatología , Valores de Referencia , Factores de Tiempo , Adulto JovenRESUMEN
Although measurement of maximum voluntary biting force is an important indicator of health of the masticatory system, few commercially available transducers have been validated for routine clinical use. The T-Scan III system records distribution of relative forces around the tooth row during clenching, but not absolute forces. This study assesses the reliability of T-Scan sensors with and without protection materials and develops calibration curves that allow measurement of absolute forces with the T-Scan III.
Asunto(s)
Fuerza de la Mordida , Análisis del Estrés Dental/instrumentación , Prostodoncia/instrumentación , Transductores de Presión , Calibración , Análisis del Estrés Dental/métodos , Dentaduras , Humanos , Prostodoncia/métodos , Reproducibilidad de los ResultadosRESUMEN
Mucormycosis is a fulminant fungal infection that occurs most often in diabetic and immunocompromised patients including those with hematologic malignancies. In this case, a patient with acute myelogenous leukemia developed mucormycosis in a recent mandibular extraction site. The successful management of this patient demonstrated that early diagnosis, aggressive surgical and medical treatment and resolution of the underlying disease could improve the prognosis for survival. A case is made for the role of smoking as an initiator of mucormycosis, and treatment considerations for controlling periodontal and pulpal disease before chemotherapy are discussed.
Asunto(s)
Atención Dental para Enfermos Crónicos/efectos adversos , Leucemia Mieloide Aguda/complicaciones , Enfermedades Mandibulares/microbiología , Mucormicosis/etiología , Humanos , Huésped Inmunocomprometido , Leucemia Mieloide Aguda/inmunología , Masculino , Enfermedades Mandibulares/etiología , Persona de Mediana Edad , Mucormicosis/inmunología , Neutropenia/complicaciones , Fumar/efectos adversos , Extracción Dental/efectos adversosRESUMEN
Critical events in the adaptation of osseous tissues to implant materials involve initial calcification of the newly synthesized bone. Previous studies indicated that bone-bonding but not nonbonding glass ceramics increase the matrix vesicle number, thereby compensating for delayed maturation of the extracellular organelles. The present study assessed whether this was also true for metal implants commonly used in orthopaedics and oral medicine. Bone-bonding titanium (Ti) or nonbonding stainless steel (SS) implants were placed in the right tibias of Sabra rats following ablation of the marrow. At 3, 6, 14, and 21 days postinjury, newly formed endosteal bone in the treated and contralateral limbs was removed and matrix vesicle-enriched membranes isolated. Alkaline phosphatase and phospholipase A2 specific activities and phosphatidylserine (PS) content were determined and compared with those of a nonsurgical control group. Results show that matrix vesicle alkaline phosphatase and phospholipase A2 activity and PS content was increased in the Ti-implanted limbs at 6 (peak), 14, and 21 days, although at levels less than observed in normal healing. Alkaline phosphatase activity remained elevated throughout the healing period. In contrast, these parameters were markedly inhibited in the SS-implanted limbs with respect to Ti or to normal healing. Both implants altered the systemic response associated with marrow ablation, but in an implant-specific manner. The results support the hypothesis that cells adjacent to bone-bonding materials can compensate for negative effects on primary mineralization during osteogenesis, whereas cells adjacent to nonbonding materials either do not compensate or are further depressed. The data support the use of the rat marrow ablation model as a tool for rapid, initial assessment of biomaterials in bone.