Biomedical subjects

P T George

Publications and source records attributed to P T George.

17 recordsLinked to original sources

PubMed2001

Is adjustability advantageous in mandibular advancement appliances in the treatment of sleep-disordered breathing?

Mandibular advancement appliances (MAD) that can adjust the amount of mandibular protrusion in response to treatment results are becoming popular with dentists who treat sleep-disorder breathing. Clinicians commonly assume that they are more efficacious and more comfortable to wear than monoblock appliances. An adjustable MAD was compared with one that stabilized the mandible at 70% of the protrusive path. There was not a significant difference in their overall efficacy. The adjustable MAD appeared to be more effective in the more severe cases, presumably due to the greater mandibular advancement; the nonadjustable MAD appeared to be more effective in the less severe cases, presumably due to the greater mandibular stabilization. Existing research was examined and biomechanical principles were considered. Insufficient research exists to definitely evaluate the pros and cons of adjustability vs. stability. There does not appear to be sufficient evidence to support the assumption that adjustable MADs are more efficacious or more comfortable to wear than monoblock appliances.

Humans↗

PubMed2001

Sleepiness, troika of consciousness cycle, and the Epworth sleepiness scale.

Excessive daytime sleepiness (EDS) is an important indicator when diagnosing sleep-disordered breathing and evaluating its treatment results. However, there appears to be some confusion as to what exactly is sleepiness; Dorland's Illustrated Medical Dictionary does not help. The medical literature was reviewed in order to assemble a schematic model that would suggest a definition of sleepiness and how it can be measured. The derived model is entitled the troika of consciousness cycle (TCC). It assumes that the presence of wakefulness, nonrapid eye movement sleep (NREMS), and rapid eye movement sleep (REMS) is determined by the interactions of four drives: two promoting wakefulness and one each for the two sleep states. The TCC illustrates that inadequate sleep results in sleep debt, but that sleepiness is determined solely by the nearness of the secondary wake drive line to the NREMS drive line. Contact of these lines indicates dozing, a change in consciousness state, an observable event. The probability of this event may be defined as objective sleepiness; this is what the Epworth sleepiness scale (ESS) attempts to measure. Studies indicate that the ESS can determine EDS with greater sensitivity and selectivity than either the multiple sleep latency test or the maintenance of wakefulness test.

Activity Cycles↗

PubMed2001

Selecting sleep-disordered-breathing appliances. Biomechanical considerations.

BACKGROUND: Dentists who wish to provide sleep-disordered-breathing therapy have many different mandibular advancement devices, or MADs, from which to select. Documented research directly about the variations in MADs is sparse. TYPES OF STUDIES REVIEWED: The author reviewed dental and medical literature dealing with biological and mechanical principles affecting the function of MADs. RESULTS: The author found that MADs vary in four major areas: freedom of mandibular movement, amount and rigidity of dental coverage, amount of mandibular advancement and amount of bite opening. Each of these areas appears to affect the appliance's efficacy, safety or both. The main potential detrimental effect of MADs is occlusal shifting. The author presents biological and mechanical considerations in an attempt to determine the optimum parameters for each of the MAD variation areas. The MAD must be constructed in a manner and with material that secures the mandible in its optimum position. The optimum mandibular position needs to be captured and transferred to the articulator with an accurate construction bite. CLINICAL IMPLICATIONS: MAD therapy may last a lifetime. Therefore, dentists must consider the efficacy and the safety of an MAD when selecting an appliance. Since occlusal shifting appears to be the main potential detrimental effect, dentists should consider all available means to monitor and minimize these changes.

Biomechanical Phenomena↗

PubMed1993