The influence of occlusal trauma on gingival recession and gingival clefts.

The aim of this study was to investigate the centric occlusal contact pattern in maximum intercuspation and to study the nature of occlusal contacts during maximum intercuspation to protrusive, lateroprotrusive and lateral excursive movements. Fifty subjects having gingival recession and ten subjects having gingival clefts belonging to age group of 18-25 years were selected after obtaining informed consent from the student's population. The selected subjects were examined and the location and extent of gingival recession, gingival clefts and occlusal wear facets were recorded. The type of occlusion and the nature of occlusal contact in maximum intercuspation and eccentric mandibular movements were also recorded using articulating foil and shimstock. Chi square test, Fisher's exact test (F) and Z test were used to statistically analyse the data obtained. Among the three occlusal concepts, gingival recession was more commonly related to group function than to canine protected occlusion. Canine protected occlusion was associated with gingival recession on the labial surface while in group function occlusion; the recession was distributed equally on the facial surface of the anterior as well as posterior teeth. Nearly all subjects showed interferences in protrusive, lateroprotrusive and lateral excursive movements on teeth showing gingival recession and gingival clefts. Occlusal wear was seen on all teeth having gingival clefts and on most teeth having gingival recession. These results suggest that occlusal interferences in maximum intercuspation and eccentric movements in one form or the other and absence of mutually protected occlusion can contribute to gingival lesions such as gingival recession and clefts.

The incisive papilla: a significant landmark in prosthodontics.

Several investigators have studied the horizontal relationship between incisive papilla and maxillary central incisor and measured the papilla incisor distance in dentate subjects to extrapolate this distance as a guide to place maxillary central incisors in complete dentures. Based on this premise, incisive papilla is recognized as an important landmark in complete denture construction. Papilla incisor measurements were made either from the middle or posterior border of the papilla and certain ethnic and national norms have been recommended to set the central incisors in complete dentures. This study was done on Dravidian dentate subjects to relate incisive papilla to central incisors and canines and also to ascertain its shape. During its transition to the edentulous state, incisive papilla changes its shape consequent to remodeling of the alveolar bone, palatal mucosa and interdental papilla following extraction of central incisor teeth. It was found that the papilla in dentate is not always round but seen in several forms. In some it was a double papilla and in a few it was rudimentary. The center of the papilla also changes from its dentulous to edentulous state. The posterior border is a relatively stable landmark since it undergoes least change after extraction of anterior teeth.

Single Stage Silicone Border Molded Closed Mouth Impression Technique-Part II.

Functioning of a complete denture depends to a great extent on the impression technique. Several impression techniques have been described in the literature since the turn of this century when Greene [Clinical courses in dental prothesis, 1916] brothers introduced the first scientific system of recording dental impression. Advocates of each technique have their own claim of superiority over the other. The introduction of elastomeric impression materials [Skinner and Cooper, J Am Dent Assoc 51:523-536, 1955] has made possible new techniques of recording impression for complete denture construction. These rubber like materials are of two types; one has a polysulfide base and is popularily known as polysulfide rubber (Thiokol and Mercaptan). The other variety has a silicone base known as silicone rubber or silicone elastomer. Silicone elastomers are available in four different consistencies; a thin easy flowing light bodied material,a creamy medium bodied material, a highly viscous heavy bodied material and a kneadable putty material. This paper describes an active closed mouth impression technique with one stage border molding using putty silicone material as a substitute for low fusing compound.

The effect of 0.5% sodium hypochlorite and 2% glutaraldehyde spray disenfectants on irreversible hydrocolloid impression material.

Infection control has assumed prime importance in dentistry. It is a prime concern in prosthodontics as well, where impressions materials are most commonly used. Impression materials can act as a medium for cross infection. To prevent cross infection many products are being developed. Among them 0.5% Sodium hypochlorite and 2% Glutaraldehyde are considered effective. This study was done to asses the efficacy of 0.5% Sodium hypochlorite and 2% Glutaraldehyde on irreversible hydrocolloid impression material. The result of the study indicated that they are effective against both Gram positive and Gram negative organisms and their use is recommended.

Interregional variation of longitudinal relaxation rates in human brain at 3.0 T: relation to estimated iron and water contents.

In a study of interregional variation of the longitudinal relaxation rate (R(1)) in human brain at 3 T, R(1) maps were acquired from 12 healthy adults using a multi-slice implementation of the T one by multiple readout pulses (TOMROP) sequence. Mean R(1) values were obtained from the prefrontal cortex (0.567 +/- 0.020 sec(-1)), caudate head (0.675 +/- 0.019 sec(-1)), putamen (0.749 +/- 0.023 sec(-1)), substantia nigra (0.873 +/- 0.037 sec(-1)), globus pallidus (0.960 +/- 0.034 sec(-1)), thalamus (0.822 +/- 0.027 sec(-1)), and frontal white matter (1.184 +/- 0.057 sec(-1)). For gray matter regions other than the thalamus, R(1) showed a strong correlation (r = 0.984, P < 0.0001) with estimated regional nonheme iron concentrations ([Fe]). These R(1) values also showed a strong correlation (r = 0.976, P < 0.0001) with estimates of 1/f(w) obtained from MRI relative proton density measurements, where f(w) represents tissue water content. When white matter is included in the consideration, 1/f(w) is a better predictor of R(1) than is [Fe]. An analysis based on the fast-exchange two-state model of longitudinal relaxation suggests that interregional differences in f(w) account for the majority of the variation of R(1) across gray matter regions. Magn Reson Med 45:71-79, 2001.

Three-dimensional endocardial mapping system using a novel x-ray imager and locating catheter.

Percutaneous radiofrequency catheter ablation (RFCA) has a very high success rate for certain arrhythmias, such as Wolff-Parkinson-White syndrome and idiopathic ventricular tachycardias in the right ventricular outflow tract. These arrhythmias are typically characterized by a single site of arrhythmogenic tissue that is well bounded by anatomic markers. Success rates for RFCA for reentrant ventricular tachycardias, tachycardias not closely associated with anatomic markers, and those having larger tissue areas requiring multiple overlapping lesions have been significantly lower. An endocardial mapping system is being developed that includes a fluoroscopic imager that scans the field of view with a series of small x-ray beams and electrophysiology catheters modified to include miniature x-ray sensor elements. Preliminary work indicates that the accuracy of determining the mapping catheter location relative to the reference catheters will be +/- 1.5 mm. Substituting a highly accurate three-dimensional coordinate system for anatomic markers could improve the success rate of RFCA for complex arrhythmias.

The running meditation response: an adjunct to psychotherapy.

The physical technique of slow, long distance running and the mental centering devices of T. M. are combined, using hypnosis in some cases, to enhance a "peak experience," or altered state of consciousness. Indications and contraindications to this technique are described for various psychiatric, psychosomatic and somatic syndromes, and its use as an adjunct to formal individual and group psychotherapy is discussed.