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At least 685 records · Page 38Linked to original sources

PubMed2002

Tooth surface loss: does recreational drug use contribute?

OBJECTIVE: This pilot study was designed to measure tooth wear in a sample of 13 subjects who regularly use amphetamine-like drugs (Ecstasy, amphetamines) and compare the observed wear with a matched sample of nondrug users. DESIGN: The two groups, both composed of 13 undergraduate students, were matched for age and sex. Other factors influencing tooth wear were controlled by matching the groups on their responses to a questionnaire asking about recognised common causes of tooth wear. The participants teeth were examined and the degree of wear scored according to a tooth wear index. RESULTS: Severity of occlusal tooth wear of the lower first molar teeth was significantly greater in the drug user group than in the control group (P<0.05). No other statistically significant differences between the groups were found. CONCLUSION: Regular use of amphetamine-like drugs could be associated with increased posterior tooth wear.

Adolescent↗

PubMed1998

Sphere spectrophotometer versus human evaluation of tooth shade.

The purpose of this study was to compare an objective to a subjective method of tooth shade evaluation using the SP78 sphere spectrophotometer and human visual analysis. Twenty extracted fully developed human maxillary teeth had their L* values (lightness) read by the SP78 on day 1 and then again on day 14. Using a blind method, five human evaluators then attempted to match shade tabs from a six-tab experimental Vita shade guide to the same teeth on days 1 and 14. The SP78 L* values read for each tooth were evaluated for a match between those obtained on day 1 and those read on day 14. The results of human evaluation of tooth shade were compared among the evaluators and then between themselves over time. Finally, the ability of human evaluators to match tooth shade was compared with the results obtained with the SP78. The SP78 reproduced L* readings within the standard error of the machine (< or = 1.0) in 16 of 20 (80%) teeth. In contrast, interevaluator agreement expressed as majority agreement (3, 4, or 5 of 5 evaluators agreeing) was only 10 of 20 (50%) teeth on day 1 and 13 of 20 (65%) teeth on day 14. Intraevaluator agreement over the experimental period ranged from 20 to 60%. The results of this study confirm that human evaluation of tooth shade is unreliable and that the SP78 sphere spectrophotometer can provide a more predictable and accurate method of evaluating tooth shade in vitro. This finding opens up a new avenue of investigation for testing the effectiveness of materials and techniques in bleaching discolored teeth.

Color↗

PubMed1993

Tooth formation in patients with oligodontia.

Oligodontia is defined as the congenital absence of many teeth. The aim of the present study was to evaluate tooth formation in patients with oligodontia who were missing six or more teeth. The oligodontia sample was compared to a control group matched for race, sex and age. Calcification stages of the teeth of the left side of the mandible were rated. Patients with oligodontia showed a tendency for delayed tooth formation. Significant differences in tooth formation were found between males with oligodontia and the control group for several stages of tooth formation. In females only stage 5 of the second mandibular molar showed a significant difference. Because of the great individual variation in tooth formation in patients with oligodontia, tooth formation in patients with oligodontia should be individually examined before starting treatment.

Adolescent↗

PubMed1989

The periodontal enigma: eruption versus tooth support.

The response of the periodontal ligament is reviewed when single or repeated loads are applied to the tooth, as in mastication. A more nearly elastic recovery is produced with simulated chewing than is indicated by single semi-static applications of force. The resting position of the tooth between loadings changes with the time of day and recent loading history. An unstressed tooth extrudes at a variable rate. Soon after entry into the mouth, extrusion is a progressive feature, which manifests as eruption with consequent structural rearrangement of the periodontium. Rates of extrustion are substantially higher than eruption. Experimental evidence is presented that newly erupted teeth of monkey erupt in a similar manner to rodent incisors. Thus reduction in masticatory loads allows teeth to erupt faster than control teeth. It is concluded that the ligament is well constructed to withstand the large but short-acting forces which occur in mastication and which cause relatively small, long term effects, on the position of the tooth in the alveolus. When unstressed, mechanisms in the ligament of a tooth with a developing or fully formed root, generate a continuous net force in the order of a gram tending to cause extrusion. The position a tooth adopts is determined by the interplay of these opposing sets of greatly differing forces.

Animals↗

PubMed1991

Five-year incidence of tooth loss in Iowans aged 65 and older.

The prevalence of missing teeth has been described for US adults, but little is known about the incidence of tooth loss in any segment of the population. This study investigated the 5-yr incidence of tooth loss in a random sample of Iowans aged 65 yr and older residing in two rural counties. These people had an average of 20 teeth at baseline and approximately 40% lost at least one tooth in the subsequent 5 yr. The incidence of tooth loss was highest for mandibular molars and lowest for mandibular canines. Men were more likely than women to lose teeth. Although we were able to identify a number of statistically significant potential risk factors for tooth loss, the multivariate models that incorporated all these factors were not good predictors of which people were at highest risk for tooth loss.

Aged↗

PubMed2005

Two-year clinical evaluation of nonvital tooth whitening and resin composite restorations.

BACKGROUND: Adhesive systems, resin composites, and light curing systems underwent continuous improvement in the past decade. The number of patients asking for ultraconservative treatments is increasing; clinicians are starting to reevaluate the dogma of traditional restorative dentistry and look for alternative methods to build up severely destroyed teeth. PURPOSE: The purpose of this study was to evaluate the efficacy of nonvital tooth whitening and the clinical performance of direct composite restorations used to reconstruct extensive restorations on endodontically bleached teeth. MATERIALS AND METHODS: Twenty-one patients 18 years or older were included in this clinical trial, and 26 endodontically treated and bleached maxillary and mandibular teeth were restored using a microhybrid resin composite. Patients with severe internal (tetracycline stains) and external discoloration (fluorosis), smokers, and pregnant and nursing women were excluded from the study. Only patients with A3 or darker shades were included. Teeth having endodontic access opening only to be restored were excluded; conversely, teeth having a combination of endodontic access and Class III/IV cavities were included in the study. A Vita shade guide (Vita Zahnfabrik, Bad Säckingen, Germany) arranged by value order was used to record the shade for each patient. Temporary or existing restorations were removed, along with a 1 mm gutta-percha below the cementoenamel junction (CEJ), and a resin-modified glass ionomer barrier was placed at the CEJ. Bleaching treatment was performed using a combination of in-office (OpalescenceXtra, Ultradent Products, South Jordan, UT, USA) and at-home (Opalescence 10% PF, Ultradent Products) applications. Two weeks after completion of the bleaching, the teeth were restored using a combination of PQ1 adhesive system and Vit-l-escence microhybrid resin composite (Ultradent Products). Wedge-shaped increments were placed and cured using the VIP Light (Bisco, Inc Schaumburg, IL, USA) through a combination of pulse and progressive curing techniques. RESULTS: All but one restoration were evaluated by two independent evaluators every 6 months during a 2-year period using modified US Public Health Service criteria. No restoration failed and "alpha" scores were recorded for all parameters but color stability, which was scored "bravo." Analysis of variance showed a significant shade change between baseline (mean=14.4+/-1.9) versus 2 weeks (mean=1.6+/-0.7) and 2 years (mean=2.8+/-1.7) (p<.0001). Although a significant shade change was observed between 2 weeks and the 2-year follow-up (p=.008), no significant difference was reported between the baseline and 2 weeks (12.9+/-2) versus baseline and 2 years (11.9+/-2.3). CONCLUSIONS: Significant tooth lightening was reported after the completion of whitening therapy on devitalized teeth; shade rebound was reported in less than 50% of the treated teeth and was limited to a maximum of four shades. A microhybrid resin composite demonstrated excellent clinical performance in the restoration of all endodontically treated and bleached teeth after a 2-year evaluation period. CLINICAL SIGNIFICANCE: Nonvital tooth whitening is responsible for a significant change in color of endodontically stained teeth. Successful nonvital tooth-whitening therapy allows for conservative tooth preparation, preserving and reinforcing sound tooth structure. The proper use of modern adhesive systems along with resin composite restorations precludes the use of more extensive restorative treatment, delaying expensive crown and bridge procedures.

Carbamide Peroxide↗

PubMed2006

Tooth surface loss in adult subjects attending a university dental clinic in Trinidad.

OBJECTIVES: To determine the prevalence of tooth surface loss (TSL) in a sample of subjects attending a university dental clinic in Trinidad and to investigate the relationship to tooth brushing, medical history, parafunction and dietary habits. DESIGN: Tooth surface loss was measured clinically by the index used in the 1998 UK, Adult Dental Health Survey. SETTING: Trinidad, West Indies. PARTICIPANTS: Convenience sample of adult subjects attending The University of the West Indies Dental School Polyclinic, Mount Hope. METHODS: A questionnaire was administered and tooth surface loss measured clinically. MAIN OUTCOME MEASURES: mild, moderate and severe tooth surface loss. RESULTS: 155 subjects were examined (mean age 40.6 years) of whom 72% had some degree of TSL with the majority (52%), exhibiting mild, 16% with moderate and 4% with severe TSL. There were associations found between TSL and age (OR=3.14), reflux (OR=1.37), parafunction (OR=1.06), weekly consumption of citrus fruits (OR=1.31) and soft drinks (OR=1.78), daily consumption of alcohol (OR=1.40) and a vegetarian diet (OR=2.79). CONCLUSIONS: Tooth surface loss in this Trinidadian population group appears to be common. Data supports an association between TSL and age, reflux parafunction and certain dietary patterns.

Adolescent↗

PubMed2001

Effects of a tartar control whitening dentifrice on tooth shade in a population with long-standing natural stain.

Changing and whitening tooth color in people with long-standing tooth stain without excessive hard tissue abrasion may represent one of the more difficult challenges for whitening dentifrices. An eight-week clinical trial was conducted to evaluate change in tooth color by a silica-based, enamel-safe tartar control whitening dentifrice compared to a marketed baking soda dentifrice control. First, a screening exercise was conducted to identify individuals with long-standing extrinsic dental stain. This exercise targeted adults who reported "stained teeth" and coffee/tea drinking or smoking, but who had no recent history of dental prophylaxis. Targeted subjects were examined for stain (Lobene Index) and tooth shade/color (Vita). A total of 291 adults having extrinsic stain and discolored teeth were enrolled in the study. Subjects were randomized to one of the two treatment groups, and all dentifrice use was unsupervised. Tooth color was measured at 4 and 8 weeks from shade values collected from the 8 incisors, and averages were determined from a linear ordering of the shade guide. A total of 278 evaluable subjects completed the 8-week study. Overall, the tartar control whitening dentifrice group experienced an improvement in color, differing statistically from baseline (p < 0.001) and from the marketed control (p < 0.05). Safety profiles for the two dentifrices were generally similar. Among patients with long-standing extrinsic stain, use of the tartar control whitening dentifrice resulted in superior overall tooth shade and reduced maximum or worst color compared to the marketed baking soda dentifrice control.

Adult↗

PubMed2003

Comparison of clinical efficacy and safety of three professional at-home tooth whitening systems.

A three-cell, randomized, parallel, investigator-blinded clinical trial was conducted to compare the efficacy and safety of three professional at-home tooth whitening systems, including Crest Professional Whitestrips (6.5% H2O2), Day White 2 (7.5% H2O2) and Nite White Excel 2 (16% carbamide peroxide equivalent). Ninety subjects were randomly assigned to three groups (30/group). Subjects were instructed to use the assigned whitener following the manufacturers' instructions. Clinical examinations at baseline, and on days 3, 7, 14, and 18 (Day White), or 21 (Crest Professional Whitestrips and Nite White) included the following parameters: 1) oral tissues; 2) tooth shade by the Vitapan Classical shade guide; 3) tooth shade by a chromameter with a jig; and, 4) tooth sensitivity and gingival irritation. The results showed significant shade reductions with time in all three groups. Nite White resulted in significantly greater shade reductions in periods between days 7, 14, or 21 and baseline than did the other two systems. Tooth sensitivity and gingival irritation, which were mostly mild and transient, occurred in all groups. It is concluded that all three whitening systems evaluated are effective and safe. Nite White Excel is superior to the other two systems because it provides a greater whitening efficacy with comparable or lower incidence of tooth sensitivity and gingival irritation.

Adult↗

PubMed2005

To extract or not to extract? Factors that affect individual tooth prognosis.

A dentist evaluates a natural tooth for its quality of health. Once this is accomplished, the clinician obtains an estimate of longevity and decides whether to extract or to treat and maintain the tooth. There often are questions and doubts involved in the decision-making process in regard to the prognosis of an individual tooth. Unfortunately in dentistry, as in all biologic sciences, there are no straightforward answers to questions. This article will look at the literature in this area to help the practitioner in the decision-making process with regard to the compromised tooth. The article will concentrate on the single tooth or implant restoration. Other factors, such as the strategic value of a tooth and financial limitations in relation to long-term prognosis, will also be discussed.

Animals↗

PubMed2006

[Dissertations 25 years after date 9. How is tooth eruption regulated?].

A lot of attention has been paid to the questions of how and why teeth erupt. In the past many theories were developed, all of which showed mechanistic characteristics and suggested that a certain structure exerts force on the tooth germ to initiate its eruption. The dominant theory considered the collagenous fibres or the fibroblasts within the periodontal ligament to be the primary moving force in the eruption process. However, most research was done on continuously erupting incisors of rodents or lagomorphs, an experimental model with serious drawbacks. Because dogs, like humans, have teeth with limited eruption, 25 years ago research was carried out on tooth eruption in beagles. One of the most important conclusions of this study was that the periodontal ligament is not the primary moving force in tooth eruption, as its development only begins at the end of the eruption process. In subsequent years several others have focused their research on tooth eruption in beagles. The current state of knowledge in this field can be summarized as follows: the reduced enamel epithelium and the dental follicle control bone deposition and resorption around an erupting tooth germ, enabling its occlusal movement; the periodontal ligament develops only after its emergence in the oral cavity, and is thus not important in the eruption process; the tooth itself does not play a role in the regulation of its eruption.

Animals↗

PubMed1991

[A supernumerary primary tooth inducing impaction of primary incisor: a case report].

A case of a primary supernumerary tooth in a 18 month old girl was reported. 1. The supernumerary tooth was located in the maxillary incisor area. 2. The maxillary left primary central incisor and the primary supernumerary tooth were impacted. 3. The clinical and radiographic findings indicated that the primary tooth in the mesial position was the supernumerary tooth, and therefore it was removed. 4. Three days after extraction of the mesiodens, the left primary central incisor erupted. The tooth completely erupted in two months. 5. The radiographic examination showed no supernumerary succedenous teeth.

Female↗

PubMed1996

The force requirements for tooth movement. Part III: The pressure hypothesis tested.

Many experiments have investigated the force requirements for tooth movement; the diverse results so obtained have lead to controversy and resulted in an incomplete understanding of the true nature of tooth movement. This study analyses the results of two experiments which investigated the relation between the force applied and the rate of tooth movement from the standpoint of the pressures exerted by the tooth root on the surrounding tooth-periodontal membrane complex. The pressure hypothesis suggested by Smith and Storey is tested using the estimated projected area of the teeth moved in the experiments as a means of calculating the estimated pressures resulting from the application of orthodontic forces. The average pressure at which optimal rates of tooth movement occurred in these experiments was 197 gf cm-2.

Adolescent↗

PubMed2005

Effect of hybrid layer on stress distribution in a premolar tooth restored with composite or ceramic inlay: an FEM study.

The aim of this finite elemental stress analysis study was to evaluate the effect of hybrid layer on distribution and amount of stress formed under occlusal loading in a premolar tooth restored with composite or ceramic inlay. The mandibular premolar tooth was selected as the model based on the anatomical measurements suggested by Wheeler. The analysis is performed by using a Pentium II IBM compatible computer with the SAP 2000 structural analysis program. Four different mathematical models including the following structures were evaluated: 1) composite inlay, adhesive resin, and tooth structure; 2) composite inlay, adhesive resin, hybrid layer, and tooth structure; 3) ceramic inlay, adhesive resin, and tooth structure; 4) ceramic inlay, adhesive resin, hybrid layer, and tooth structure. Loading was applied from the occlusal surface of the restoration, and shear stresses under loading were evaluated. The findings were drawn by the Saplot program, and the results were analyzed by graphical comparison method. The output indicated that the hybrid layer acts as a stress absorber in models 2 and 4. The hybrid layer has also changed mathematical values of stress on cavity floors in both restoration types. Ceramic inlay collected the stress inside the body of the material, but the composite inlay directly transferred the stress through dental tissues. As a result, it was concluded that the hybrid layer has an effect on stress distribution under loading in a premolar tooth model restored with composite or ceramic inlay.

Acrylic Resins↗

PubMed1986

Projection of tooth pulp afferents to the thalamus of the cat. II. Distribution and characteristics of single units.

Single unit activity was recorded extra- and intracellularly in the thalamus of the cat following electrical stimulation of tooth pulp afferents. Cells activated by noxious stimuli were found in the basal ventromedial nucleus (VMB), the marginal zones of the arcuate and external nuclei of the ventrobasal complex (VBA and VBX) and the intralaminar complex. Cells found in any of these locations showed a variety of properties; they were activated at different latencies and had different patterns of input. However, cells with responses of short latency and low convergence were with few exceptions found in or close to VMB. Stimulation of tooth pulp evoked both EPSP's and IPSP's in these cells. A subpopulation of cells were found that responded to stimulation of either right or left tooth pulp afferents. 22 units, mainly located in VMB, were found that responded exclusively to stimulation of tooth pulp afferents. In the laterodorsal part of VMB cells influenced by tooth pulp stimulation were found to be antidromically activated by stimulation of the cortical tooth pulp projection area. No such cells were seen at other locations. The results of this study is in agreement with the conclusions in the companion paper (Rydenhag et al. 1986a) that VMB and the border zone between VMB and VBA are the most likely relay nuclei between tooth pulp nociceptive afferents and the cortex. The intralaminar complex is suggested to be important in the cortical arousal reactions and direction of attention following a painful stimulus.

Afferent Pathways↗

PubMed2000

Three ways to be a saber-toothed cat.

Saber-toothed carnivores, until now, have been divided into two groups: scimitar-toothed cats with shorter, coarsely serrated canines coupled with long legs for fast running, and dirk-toothed cats with more elongate, finely serrated canines coupled to short legs built for power rather than speed. In the Pleistocene of North America, as in Europe, the scimitar-cat was Homotherium; the North American dirk-tooth was Smilodon. We now describe a new sabercat from the Early Pleistocene of Florida, combining the scimitar-tooth canine with the short, massive limbs of a dirk-tooth predator. This presents a third way to construct a saber-toothed carnivore.

Animals↗

PubMed2002

A case-control study on the psychophysical and psychological characteristics of the phantom tooth phenomenon.

The objective of this study was to determine whether patients with phantom tooth symptoms have an altered sensory perception as compared to pain-free subjects. Ten patients (mean age 56, range 32-71, nine females) were diagnosed as suffering from "phantom tooth" according to a specifically designed phantom tooth questionnaire including components of the McGill Pain Questionnaire. An SCL-90 form was completed and assessment of sensory perception was carried out by determination of the threshold level for light touch sensation, two-point discrimination, and thermal sensation in a case-control design. Results. Of all the observed questionnaires, 5.7% seemed to deal with phantom tooth, with a female preponderance (ratio 9:1). Complaints were predominantly reported in the upper jaw (ratio 8:2) with the majority in the molar region (ratio 5:3). Phantom tooth subjects showed significantly lower threshold levels for light touch sensation, most markedly on the affected side. The average psychoneurotic profile showed a tendency towards higher scores for the phantom tooth subjects. Conclusion. The phantom tooth phenomenon may show a number of features which might aid differential diagnosis. To verify influences such as upper molar predominance and increased light touch sensation, another study should be performed on a larger patient sample.

Adult↗

PubMed1993

Tooth pulp primary neurons: cell size analysis, central connection, and carbonic anhydrase activity.

Cell bodies and central terminals of trigeminal primary afferent neurons innervating the mandibular molar and incisor tooth pulps were labeled by injecting various neuroanatomical tracers into these tooth pulps. The cell bodies of major constituents of primary neurons innervating the tooth pulp, cornea, and cutaneous branch of the mylohyoid nerve were large (> or = 500 microns2, 65%), medium (300-400 microns2, 35%), and small (100-200 microns2, 34%), respectively. Those innervating the tooth pulp (tooth pulp cells) had the Nissl pattern characteristic of large light cells of the A type, while those innervating the cornea were small dark cells of the B type. Thirty percent of the tooth pulp cells exhibited histochemically demonstrable carbonic anhydrase activity. The transganglionic transport of HRP-WGA indicated marked concentration of central terminals of the tooth pulp primaries in the rostral subdivisions of the brain stem sensory trigeminal nuclear complex. In contrast, central terminals of the corneal primaries were concentrated in the medullary dorsal horn.

Animals↗