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PubMed1979

[Mandibular movements during sleep].

Measurement methods using digital evaluation are suitable for determining spacing. Important parameters, such as distribution of spacing during the night, frequency and duration of grinding movements, mean and most frequent spacing, were calculated. We also used the same method to measure pressure exerted on the headgear and the activator as well as to evaluate the interocclusal spacing in subjects wearing orthodontic apparatuses. Additional studies are planned in regard to teeth grinding, individuals with unusual habits, distinctive sleeping positions, and obstructed occlusion.

Activator Appliances↗
PubMed1992

Lymphatic vessels of the human dental pulp in different conditions.

The characteristics of the lymphatic vessel endothelial wall have been investigated in human normal and inflamed dental pulps. In normal pulps the endothelial wall is characterized by the presence of micropinocytotic vesicles and intraparietal channels. In the inflamed pulpal tissue, where an increase in interstitial fluid pressure occurs, the distended endothelial wall presents open junctions between endothelial cells and the openings of the intraparietal channels. Moreover the micropinocytotic vesicles disappear. The cytoplasm of the endothelial cells is characterized by the presence of numerous Weibel-Palade bodies, which increase in number in the dilated vessels. In the fibrillar apparatus surrounding the lymphatic vessel wall collagen fibrils are the prevalent component, while elastic fibers are not present. The different morphological properties of the lymphatic vessels are compared and discussed with regard to the variation of the functional conditions of the tissue.

Adult↗
PubMed1998

Mechanism of toxic action of fluoride in dental fluorosis: whether trimeric G proteins participate in the disturbance of intracellular transport of secretory ameloblast exposed to fluoride.

In enamel fluorosis model rats treated with sodium fluoride, secretory ameloblasts of incisor tooth germs exhibited disruption of intracellular trafficking. We examined whether heterotrimeric G proteins participated in the disruption of vesicular trafficking of the secretory ameloblast exposed to fluoride, using immunoblotting and pertussis toxin (IAP)-induced adenosyl diphosphate (ADP)-ribosylation for membrane fractions of the cell. Immunoblotting of crude membranes, post supernatants of the ameloblast, with anti-G(alpha i3/alpha o) and anti-G(alpha s) antibodies showed that Gi3 or Go proteins existed in the secretory ameloblast, but Gs protein did not. Immunoblotting of the subcellular membrane fractions indicated that the Gi3 or Go proteins were located in the Golgi membrane, but were not in the rough endoplasmic reticulum (rER) membrane. Autoradiograph of IAP-induced ADP-ribosylation, however, showed the existence of IAP-sensitive G proteins both in rER and Golgi membranes. Fluoride treatment decreased the G proteins bound to both membranes. These findings indicate that different G proteins, both of which are IAP-sensitive, are present in the rER and Golgi apparatus, and suggest that these G proteins participate in the disturbance of intracellular transport of the secretory ameloblast exposed to fluoride.

Adenosine Diphosphate Ribose↗
PubMed1999

Does chewing performance depend upon a specific masticatory pattern?

The purpose of this article is to review the literature concerning the ideal chewing pattern for best chewing performance. We conclude that at this time there is not one ideal chewing pattern which can be used clinically or in research to assess the health of the mastication apparatus nor to predict chewing performance. It is clear that human masticatory behaviour is one of the most complex human behaviours. Chewing is under the control of the central pattern generator located in the brain stem but is influenced by dental and temporomandibular joint morphology. The most important portion of the chewing cycle is the area entering and leaving the intercuspal position where gliding contacts occur. Maximal chewing capability will likely occur when the chewing pattern follows the dental anatomy unique to the individual. The chewing cycle appears to increase the lateral component of its movement when increased chewing efficiency is required. These situations include increased hardness or the size of bolus, the position of the bolus and the results of the proceeding chewing stroke. The chewing pattern for any one cycle is influenced by a number of factors, thus it is not surprising that the question of the ideal chewing pattern remains unresolved.

Dental Occlusion↗
PubMed1977

Providing optimal oral health.

Oral health is achieved with adequate nutrition, a properly functioning masticatory apparatus, a flow of saliva, and mechanical cleaning of the oral cavity by artificial means. Interruption of one or more of these factors produces significant changes in the oral cavity, leading to collection of debris and formation of plaque, tartar, dental caries, and periodontal disease. The astute nurse will consider these factors in her overall assessment of the client and will institute in the total plan of care specific nursing measures to prevent, minimize, or reverse changes in the oral cavity. The choice of agents to be used for oral hygiene should be based on a knowledge of their characteristics and function rather than on their convenience of preparation or tradition. The method of implementation should be determined by the client's status mentally and physically, and the frequency of care should be determined by a continued evaluation of the results achieved. Too often in nursing we accept into use agents or methods introduced for care with little or no evidence of their effectiveness, and tend to perpetuate their use because of their convenience or our assumptions that they are beneficial. A review of the literature regarding oral hygiene has helped focus on the areas of agreement as well as on the areas of question regarding the efficacy of the components of oral care: the criteria for assessment, the agents selected, the methods used, and the frequency required. Further scientific inquiry should be done by nurses to build on the knowledge and criteria enumerated--specifically, to define further criteria for assessing changes in the condition of the oral cavity--and to study the effects of various agents on the pH of the mouth.

Dentifrices↗
PubMed1995

Quantitative evaluation of the cutting quality and abrasive resistance of scalers.

An automatic scaling apparatus that simulated the scaling process of hand instrumentation was developed to quantitatively analyze the cutting quality and abrasive resistance of scalers. We first tested 4 synthetic resins as the abraded material. Of the 4 synthetic resins tested, polycarbonate resin proved most similar to dentin. The effects of lateral scaling forces (700, 500, and 300 dyne) and scaler angles (70 degrees to 95 degrees) on the cutting quality and abrasive resistance of scalers were evaluated quantitatively by the amount of the abraded material worn away in 1,000 strokes. Comparison of the 3 scaling forces showed a greater amount of abrasion at higher force than that at lower force. This suggests that the decrease in the amount due to abrasion could be compensated by increasing the lateral scaling force. Regarding the scaler angle, results indicated that the amount of material removed increased with an increase of the scaler angle up to 70 degrees, but then rapidly decreased at an angle of 90 degrees or more. The most effective scaling angle was 87 degrees, and this was not affected by scaling force. These results suggest that a greater amount of removal could be obtained at a scaling angle of 87 degrees and a scaling force of 700 dyne. The present findings suggested the automatic scaling apparatus could be a useful tool for quantitatively evaluating the cutting quality and abrasive resistance of scalers.

Analysis of Variance↗
PubMed1975

[Vacuolisation of odontoblasts and regressive metamorphoses from viewpoint of pulp-dentin system function].

The authors, after presenting a critical definition of the problems dealt with in their present paper in addition to giving an evaluation there of from the point of view of a constant increase of knowledge, describe the biological functions of the cell with particular reference to the cell's vacuolar apparatus. They then characterize the pulpodentinal system, outlining the functional adaptation of the endodontal vascular apparatus in the light of intrascopic results, the clinical importance of which is discussed at length.

Adult↗
PubMed1977

[Quantitative interpretation of registrations on the Stuart pantograph I. the method].

Stuart pantography records the extreme movements of the mandible. A modified reproducible method is described which furnishes comparable graphs, if the apparatus is mounted and the pantographic records are made in a standardized way corresponding to the geometric relations. This standardized method is presented and discussed.

Dental Articulators↗
PubMed2002

[Long-term evaluation of filling from selected composite materials and their effect on tooth pulp].

The aim of this work was to assess the long-term performance of several composite fillings and the reaction of the dental pulp. The study group consisted of 102 patients treated at the Department of Conservative Dentistry, Pomeranian Academy of Medicine, and at the dentistry office of the author. Altogether, 155 restorations were done with Herculite, Pertac Hybrid, Valux Plus and Heliomolar materials. The patients reappeared for follow-up after 1, 3 and 5 years and the restorations were examined clinically using the quality criteria of Ryge for surface, shape and marginal adherence of the restoration. Marginal shunt was studied with extracted teeth and malachite green under conditions resembling those of the oral cavity. Electrical excitability of the pulp was determined with the Vitality Scanner apparatus. Opinions of the patients were sought with a questionnaire. The results were subjected to statistical analysis. No statistically significant differences between the composite materials used were found on the basis of Ryge's criteria, except for Pertac Hybrid which revealed deterioration of surface quality and adherence. Significantly worse marginal adherence with all composites was noted for class I defects according to Black. Electrical excitability of the dental pulp was uniformly reduced after five years from placement of the filling. The reduction was most evident for class I and II defects. A minor marginal shunt was found for all composite materials. Most of the patients were satisfied with the quality of the fillings.

Acrylic Resins↗
PubMed2005

Oral manifestations of diabetes.

Periodontal disease, a microvascular complication of diabetes mellitus, is a group of infections and lesions affecting the tissues that form the attachment apparatus of a tooth or teeth. An individual with uncontrolled diabetes will have an increased risk of infection and abnormal healing time that will compromise the health of the oral cavity. A collaborative team approach between the home care clinician and dental professionals results in accurate patient assessment and education that results in better overall health outcomes.

Diabetes Mellitus↗
PubMedDate not supplied

[Effects of cytochalasin B and colchicine on dental cytodifferentiation in vitro].

The effects of various concentrations of cytochalasin B and colchicine on the polarization of odontoblasts and ameloblasts of mouse tooth buds cultivated in vitro, were studies. It was shown that cytochalasin B, deside its action on the microfilaments, had important cytotoxic effects; dilatation of the odontoblast's processus, accumulation of secretory granules in the Golgi apparatus, dilatation of mitochondria, inhibition of polarization or depolarization of odontoblasts and ameloblasts. These modifications resulted chiefly from the lesion of microtubules which seem to play an important role in the polarization of the cells studies.

Ameloblasts↗
PubMed1988

Surface analysis of tarnished dental alloys.

Six crown and bridge alloys ranging in nobility between 25-63 wt % (18-45 at %) were analyzed by optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and secondary ion mass spectroscopy (SIMS), as well as by L*a*b* colorimetry before and after in vitro tarnishing in artificial saliva with and without additions of 0.00016, 0.016, and 1.6 % Na2S with a rotating wheel apparatus. All alloys except the lowest of 18 at % changed colors to about the same degree after 72 h of tarnishing. All alloys decreased in L*, while increased in both a* and b*, thus appearing darker and with increased redness and yellowness. This was due to localized darkening and to other products. For all alloys except one, saliva without sulfide promoted color changes more severe than for saliva with 0.016 % Na2S. For the most part, analysis by EDS was unable to detect differences between the tarnished films and the as-polished surfaces. SIMS analysis, however, showed changes in the substrate ion (Cu, Ag, Pd, and In) peak intensities. In most cases the intensities decreased and with the decrease greater with the sulfide-free saliva than with sulfide-containing. This indicated that sulfide promoted insoluble deposition of products. Changes in the Ag, Pd, and In peak intensities followed much the same pattern as with Cu. The as-polished surfaces, even though carefully prepared, showed much contamination in the form of organics, namely C, CH, N, NH, O, CHN, CN, as well as from Na, K, Ca, Si, S, Cl, and others. Most tarnished surfaces showed large increases in Na, K, and Ca, and with the sulfide-free saliva being more severe in this regard. The mass spectrum also showed peaks with atomic mass units in the range 55-58 related to only some of the tarnished surfaces.

Color↗
PubMed2002

Craniodental variation among Macaques (Macaca), nonhuman primates.

BACKGROUND: In terms of structure and function, the skull is one of the most complicated organs in the body. It is also one of the most important parts in terms of developmental and evolutionary origins. This complexity makes it difficult to obtain evolutionary assessments if, as is usually the case with fossils, only part of the skull is available. For this reason this study involves a set of comparisons whereby the smallest functional units are studied first, and these built up, through a triple-nested hierarchical design, into more complex anatomical regions and eventually into the skull-as-a-whole. This design has been applied to macaques (Macaca) in order to reveal patterns of variation at the different levels. The profiles of such variation have been obtained both within and between species. This has lead to a search for the skull parts that have undergone similar selection pressures during evolution and comparable development patterns in both ontogeny and phylogeny. RESULTS: Morphometric analysis (Principal Components) was used to obtain these profiles of species and sex separations based on 77 cranial variables from 11 species of macaques. The results showed that 7 functional units could be aggregated into three functionally reasonable anatomical regions on the basis of similarities in profiles. These were: the masticatory apparatus containing mandible, lower teeth and upper teeth, the face as a whole combining maxilla (actually lower face) and upper face, and the cranium as a whole involving cranium and calvaria. Twenty-six variables were finally selected for analyzing the morphology of the whole skull. This last showed an overall profile similar to that revealed in the masticatory apparatus but also contained additional information pertaining to individual species and species-groups separations. CONCLUSIONS: The study provides a model for carrying out analysis of species separations and sex variation simultaneously. Through this design it seems possible to see cranio-dental elements that may result from similar developmental processes, have similar functional adaptations, and show an appropriately integrated structure morphologically. This study also implies that the biological information drawn from part of skull alone, e.g. as in studies of incomplete fossils may provide misleading information.

Animals↗
PubMed2004

Maxillary post-traumatic outcome correction. Literature review and personal experience. Part II: loss of maxillary substance (free grafts of autologous bone).

Loss of maxillary substance following trauma varies significantly in relation to the dimensions, site and type of tissue involved. Anatomical maxillary interruptions, loss of dental elements and consequent bone re-absorption give rise to altered chewing, swallowing and speech functions. Treatment of pathological conditions over the years has seen the development of surgical protocols designed to achieve simultaneous aesthetic and functional restoration of the stomatognatic apparatus. The advent of osteointegrated implantology and continual progress in pre-prosthesis surgical techniques have undoubtedly revolutionised established approaches to prosthetic rehabilitation by introducing the concept of supported implant prostheses. The implantation protocols used are a safe and reproducible treatment method suitable for adequate anchorage of such prosthetic implants; the application of such protocols in any case is subordinated to the presence of adequate morpho-volumetric bone at the skeletal bases. Depending on the entity of maxillary loss of substance, the reconstruction methods we propose, in agreement with numerous other authors, are based on the use of free and free-revascularised autologous bone grafts or, even more recently, the application of osteogenetic distraction techniques. The purpose of this article is to evaluate treatment of loss of maxillary substance following trauma by means of non-revascularised free flaps. The use of free grafts of autologous bone is elective in patients presenting bone deficits less than 6 cm with and/or without upkeep of maxillary and mandibular cortical bone continuity but without compromise to the integrity and trophism of the soft tissues.

Bone Transplantation↗
PubMed1996

Shear strength of composite bonded to Er:YAG laser-prepared dentin.

An Er:YAG laser coupled with a cooling stream of water effectively removes dental hard tissues. However, before such a system can be deemed clinically viable, some safety and efficacy issues must be addressed. We compared the bonding of composite to dentin following the preparation of the dentinal surface with either an Er:YAG laser (lambda = 2.94 microns) or a standard dental bur and with and without a subsequent acid-etching treatment. The crowns of extracted human molars were removed, revealing the underlying dentin. We removed an additional thickness of material with either a dental handpiece or an Er:YAG laser (350 mJ/pulse at 6 Hz) by raster-scanning the samples under a fixed handpiece or laser. Comparable surface roughnesses were obtained. Several samples from each group received an acid-conditioning treatment. A cylinder of composite was bonded onto the prepared surfaces. The dentin-composite bond was then shear-stressed to failure on a universal testing apparatus. The results indicate that laser-irradiated samples had improved bond strengths compared with acid-etched and handpiece controls. SEM photographs of the surfaces show exposed tubules following the laser treatment: tubules could also be exposed with acid etching. We conclude that Er:YAG laser preparation of dentin leaves a suitable surface for strong bonding or an applied composite material.

Acid Etching, Dental↗
PubMedDate not supplied

The effect of pH, temperature and plaque thickness on the hydrolysis of monofluorophosphate in experimental dental plaque.

Monofluorophosphate (MFP), an anti-caries agent commonly used in toothpaste, is known to be degraded to fluoride and orthophosphate by bacterial phosphatases in dental plaque. We have examined the effect of pH, temperature, plaque thickness and some ions on this process. Both natural plaque and artificial microcosm plaque incubated with purified MFP at pH 4-10 showed an optimum pH of approximately 8 for hydrolysis. Diffusion and concomitant hydrolysis were examined in an apparatus in which artificial plaque was held between rigid membranes separating two chambers. When MFP diffused through a plaque of 0.51-mm thickness over 4 h it was almost completely hydrolysed at pH 8, but hydrolysis on diffusion decreased as the pH deviated from 8. MFP in toothpaste extract showed a similar pH susceptibility to hydrolysis, according to the inherent pH of the toothpaste. Hydrolysis of MFP in the toothpaste was reduced by no more than 10% when compared with a matched-pH control, suggesting that other toothpaste ingredients had no major influence on hydrolysis. Transport was slower and hydrolysis at pH 6 more complete the thicker the plaque, but hydrolysis was not significantly slower at 23 degrees C than at 37 degrees C. The addition of various potential activating or inhibiting ions at 0.1 and 1.0 mmol/l had small and non-significant effects on hydrolysis. The results suggest that MFP toothpaste should be formulated and used to maximise enzymic hydrolysis of this complex anion, and that plaque pH control is probably the most important factor.

Analysis of Variance↗