SEARCH · PubMed Health

Results for “Tooth”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,117 records · Page 62Linked to original sources

PubMed2001

The influence of the restoration-tooth interface in light cured composite restorations: a finite element analysis.

This study examines the early shrinkage behaviour of dental composite resins, and in particular the interfacial stresses around the margins of a composite restoration. The development of stresses at the restoration-tooth interface can have a detrimental effect on the longevity of a restoration. The influence of this interface on the stress system generated in the tooth was examined using finite element analysis. The restoration-tooth interface was simulated using spring elements of varying spring constants (k = 1, 10(2), 10(4), 10(10) N/mm). Interfacial stresses varied from -0.15 to 0.42 MPa for a spring constant of 1 N/mm, and from -19 to 68 MPa for a spring constant of 10(10) N/mm. Correlations between stiffness at the restoration-tooth interface and higher shrinkage stresses due to restricted shrinkage were found. Interfacial failure at the upper and lower regions of the interface, as well as cuspal movements of the order of 2 microm were predicated for the model of the highest spring constant, 10(10) N/mm. The restoration-tooth interface modelled by the spring elements was seen to have a conclusive effect on the ensuing stress system, as well as the longevity of the restoration.

Acrylic Resins↗

PubMed2000

Human tooth movement in response to continuous stress of low magnitude.

Conventional orthodontic therapy often uses force magnitudes in excess of 100 g to retract canine teeth. Typically, this results in a lag phase of approximately 21 days before tooth movement occurs. The current project was undertaken to demonstrate that by using lower force magnitudes, tooth translation can start without a lag phase and can occur at velocities that are clinically significant. Seven subjects participated in the 84-day study. A continuous retraction force averaging 18 g was applied to 1 of the maxillary canines, whereas a continuous retraction force averaging 60 g was applied to the other. The magnitude was adjusted for each canine to produce equivalent compressive stresses between subjects. Estimated average compressive stress on the distal aspect of the canine teeth was 4 kPa or 13 kPa. The moment-to-force ratios were between 9 and 13 mm. Tooth movement in 3 linear and 3 rotational dimensions was measured with a 3-axis measuring microscope and a series of dental casts made at 1- to 14-day intervals. The results showed a statistical difference in the velocity of distal movement of the canines produced by the 2 stresses (P =.02). The lag phase was eliminated and average velocities were 0.87 and 1.27 mm/month for 18 and 60 g of average retraction force. Interindividual velocities varied as much as 3 to 1 for equivalent stress conditions. It was concluded that effective tooth movement can be produced with lower forces and that because loading conditions were controlled, cell biology must account for the variability in tooth velocities measured in these subjects.

Adolescent↗

PubMed2003

Tooth size-arch length relationships in the deciduous dentition: a comparison between contemporary and historical samples.

In a recent study, it was reported that maxillary and mandibular arch lengths were significantly shorter in a sample of contemporary children in the deciduous dentition compared with a historical sample from about 50 years earlier. The purpose of this study was to describe secular changes that might have occurred in tooth sizes and tooth size-arch length relationships in the same cohorts of contemporary and historical North American white children in the deciduous dentition. The 2 samples were similar in terms of geographic location, racial and ethnic backgrounds, and socioeconomic status. Both samples were restricted to white children with a normal overjet (<4 mm) and a normal anteroposterior molar relationship, no anterior open bite, and no crossbite. In addition, subjects were excluded if any permanent teeth were erupted. Measurements of mesiodistal tooth sizes and arch lengths of maxillary and mandibular arches were made, and tooth size-arch length discrepancies (TSALD) were determined. The results indicated that tooth sizes were generally similar in the 2 cohorts but slightly larger in contemporary children. Crowding, as measured by TSALD, was found to be common in the mandibular arch for contemporary children in the deciduous dentition of both boys and girls. Moreover, crowding was much more common and severe in contemporary children compared with children in the historical cohort. Further research is needed to determine whether the increase in mandibular crowding in the deciduous dentition will continue to be observed in the mixed and permanent dentitions and to further establish these possible secular trends.

Cephalometry↗

PubMed1996

The measurement of acid and alkaline phosphatase in gingival crevicular fluid during orthodontic tooth movement.

This study examines acid and alkaline phosphatase activities in gingival crevicular fluid (GCF) to learn whether bone turnover dynamics can be monitored in human subjects during orthodontic tooth movement. Three female subjects were observed longitudinally to assess tooth movement, plaque, and inflammation. For each subject, one randomly selected premolar served as the control and was not treated, and another was moved buccally with 100 gm of force. The GCF was collected weekly and assayed for phosphatases. Alkaline phosphatase peaked between the first and third weeks, followed by an increase in acid phosphatase between the third and sixth weeks. After the first week, tooth movement averaged 0.9 mm. Additional 0.9 mm of movement occurred during the next 3 weeks, followed by 1.4 mm during weeks 4 to 6. Thirty additional patients, randomly divided into headgear/biteplate, bionator, and control groups, were also sampled cross-sectionally at the maxillary first molars. The GCF phosphatase activities were assessed as functions of location on the tooth, treatment modality, duration of treatment, gingival inflammation, and plaque accumulation. The plaque index did not show a relationship to either acid or alkaline phosphatase activity on the mesial or distal in the treated groups. However, alkaline phosphatase increased with inflammation on the distal in treated groups and acid phosphatase was consistently higher on the mesial than on the distal in the treatment groups. Alternating peaks of acid and alkaline phosphatase were found in the GCF of treated teeth as functions of treatment duration. The sequence of these changes is similar to that reported for alveolar bone turnover in a rodent orthodontic tooth movement model. We conclude that phosphatase activities in GCF may be a useful means for monitoring tissue responses to orthodontic treatment.

Acid Phosphatase↗

PubMed2003

Total tooth loss and prevalent cardiovascular disease in men and women: possible roles of citrus fruit consumption, vitamin C, and inflammatory and thrombotic variables.

BACKGROUND AND OBJECTIVE: Tooth loss has been associated with cardiovascular disease (CVD), but the mechanisms are unclear. We evaluated the association of total tooth loss with prevalent CVD in men and women; as well as with citrus fruit consumption, plasma vitamin C, and inflammatory and thrombotic variables. METHODS: We used an age-and sex-stratified population survey, of men and women aged 25-74 years, in North Glasgow. RESULTS: Thirty-eight percent of women and 29% of men were edentulous. Total tooth loss was associated with prevalent CVD in both sexes. After adjustment for major potential confounders (age, sex, smoking, and social class), the odds ratio (95% CI) for prevalent CVD was 1.55 (1.13, 2.13) in the edentulous. Total tooth loss was also associated with low citrus fruit consumption and low plasma vitamin C levels, increased plasma C-reactive protein in men, and with increased plasma interleukin-6, fibrinogen, and factor VIII levels in women. CONCLUSION: Prevalent CVD is associated with total tooth loss. Possible mechanisms include low intake of citrus fruit, and hence, low plasma vitamin C levels, and a predisposition to low-grade inflammation and thrombosis. It may be prudent to ensure adequate vitamin C intake in people with no teeth.

Adult↗

PubMed2001

The frequency of 17p11.2 duplication and Connexin 32 mutations in 282 Charcot-Marie-Tooth families in relation to the mode of inheritance and motor nerve conduction velocity.

The 17p11.2 duplication and Connexin 32 (Cx32) mutations are the most frequent gene mutations responsible for Charcot-Marie-Tooth diseases. We classified 282 Charcot-Marie-Tooth families according to the median motor nerve conduction velocity of the index patient and the mode of inheritance, and screened them for 17p11.2 duplication and Cx32 mutations. Forty-seven percent of the Charcot-Marie-Tooth families had median motor nerve conduction velocity under 30 m/s (group 1), 15% between 30 and 40 m/s (group 2), and 28% over 40 m/s (group 3). Spinal Charcot-Marie-Tooth (group 4) was observed in 7% of the families. Modes of inheritance were not similarly represented among the different groups. The 17p11.2 duplication was detected in index patients of group 1 only, and accounted for 83% of the familial cases and 36% of the isolated cases. In contrast, 21 Cx32 mutations were detected to variable degrees in groups 1-3, but were most numerous by far in dominant families of group 2 (44%). This systematic approach was taken to estimate the frequency of 17p11.2 duplication and Cx32 mutations in the different Charcot-Marie-Tooth subgroups, in order to propose a practical strategy for molecular analysis.

Adult↗

PubMed2000

Inferior alveolar nerve transection inhibits increase in osteoclast appearance during experimental tooth movement.

To evaluate the role of sensory nerve innervation in alveolar bone remodeling during experimental tooth movement, we investigated histomorphometrically the influence of sensory nerve denervation on bone metabolism. Seven days after inferior alveolar nerve (IAN) transection or a sham operation in rats, orthodontic force was applied to the animals by inserting an elastic module interproximally between the lower first molar and second molar. Twenty-four hours after the application of the orthodontic force, osteoclast number, osteoclast surface, and osteoblast surface were measured on the trabecular bone surface in the interradicular septum of the lower second molar. The distribution of sensory nerve fibers immunoreactive to antibody against calcitonin gene-related peptide (CGRP) was also evaluated. In the sham-operated rats, CGRP-immunoreactive nerves were observed to be distributed along the blood vessels in the trabecular alveolar bone. Experimental tooth movement resulted in a fivefold increase in the number of osteoclasts and in increased immunoreactivity of nerves to anti-CGRP in the trabecular bone. However, IAN transection depleted the immunoreactivity to anti-CGRP and reduced the osteoclast number and osteoclast surface significantly. On the other hand, in the rats that were not subjected to experimental tooth movement, there was no significant difference in osteoclast number between sham-operated and IAN-transected rats. Significant changes were not observed in osteoblast surfaces associated with experimental tooth movement or nerve transection. These findings suggest that sensory nerves play an important role in regulating bone resorptive activity during experimental tooth movement.

Animals↗

PubMed2001

Prospective study of tooth loss and incident esophageal and gastric cancers in China.

OBJECTIVE: To determine the association between tooth loss and the risk of developing esophageal squamous cell carcinoma, gastric cardia adenocarcinoma, or gastric non-cardia adenocarcinoma in a prospective study. METHODS: Cox proportional hazards regression was used to examine these associations in a 28,868-person cohort followed prospectively for 5.25 years. The baseline questionnaire included questions regarding tooth loss, and individuals reporting lost teeth had their teeth counted by study personnel. The analytic cohort included 620 esophagus, 431 gastric cardia, and 102 gastric non-cardia cancer cases. RESULTS: Tooth loss was associated with a significantly elevated risk of developing all three cancers. When examined as median splits, tooth loss was associated with a relative risk (RR) (95% confidence interval, CI) of 1.3 (1.1-1.6) in the esophagus, 1.3 (1.0-1.6) in the gastric cardia, and 1.8 (1.1-3.0) in the gastric non-cardia. Further analysis demonstrated that this increased risk was most strongly associated with the loss of the first few teeth and was primarily confined to the younger members of our cohort. CONCLUSIONS: In this cohort tooth loss increased the risk of developing upper gastrointestinal cancer. We hypothesize that this may be related to alterations in oral bacterial flora and subsequent increases in the in-vivo production of carcinogens such as nitrosamines.

Adenocarcinoma↗

PubMed2001

Localization of activated caspase-3-positive and apoptotic cells in the developing tooth germ of the mouse lower first molar.

This study examined the immunohistochemical detection of activated caspase-3, and its association with apoptosis, during tooth morphogenesis of the mouse lower first molar. The distribution of cells positive for caspase-3 closely corresponded with the localization of the terminal deoxynucleotidyl transferase-mediated deoxyuridine-5'-triphosphate-biotin nick end labelling (TUNEL)-positive apoptotic cells through the developmental course of tooth germs from embryo day 12 (E12) to E19, thus showing that the apoptosis occurring in the developing odontogenic tissue was induced by the activation of the caspase family. The specific distribution pattern of apoptotic cells in the developing odontogenic epithelial tissue from the initiation (E12) of tooth germ to the completion of tooth crown morphology (E19) also suggests that apoptotic events are related not only to a deletion of functionally suspended cells, but also participate in initiation and the completion of tooth morphogenesis. Electron microscopic examination revealed that apoptotic cells were present in the primary enamel knot, and these apoptotic cells were phagocytized by neighbouring odontogenic epithelial cells, thus indicating the prompt disposal of any dead cells by epithelial cells.

Animals↗

PubMed1994

Effects of early placement of a single tooth implant. A case report.

A single tooth implant was placed in a boy aged 12 years and 3 months. The case has been followed for more than 4.5 years. The fixture did not move together with the adjacent teeth as the maxillary growth went on. There was no "loss" of marginal bone on the side of one adjacent tooth where the distance between implant and tooth was appropriate. But a "loss" of marginal bone (measured from the cemento-enamel junction) was noted on the other adjacent tooth where the fixture had been placed too close to the tooth.

Age Factors↗

PubMed2000

Using partial recording to assess tooth wear in older adults.

OBJECTIVES: To establish whether partial recording can be used for the measurement and reporting of tooth wear data in samples of adult populations, whilst maintaining the usefulness of the index. METHODS: Using whole mouth coronal tooth wear data from a large random population sample of 1200 dentate older adults in England, several different partial recording systems were investigated to establish which teeth would maintain a high level of sensitivity for the most economic use of codes and index teeth. Tooth wear data were recorded on a surface-by-surface basis on all teeth in the sample using the tooth wear index. RESULTS: Five different partial mouth recording systems were assessed, including half-mouth scoring, assessment of just upper or just lower anterior teeth, assessment of all anterior teeth and use of six index teeth. The 12 anterior teeth were the ones most often affected by moderate or severe wear, and when all 12 teeth were used as the index teeth few wear cases were missed, and all the most extensive and severe cases of coronal wear were classified as having some wear. A limited index of only six anterior teeth (three uppers and three lowers) was almost as sensitive, but allowed less flexibility when reporting the extent of coronal wear. Other systems for partial recording were less sensitive. CONCLUSIONS: Partial recording using six or 12 anterior teeth is appropriate for measuring and reporting tooth wear data in large population surveys.

Age Distribution↗

PubMed2000

Delay of tooth eruption in null mice devoid of the type I IL-1R gene.

Interleukin-one alpha (IL-1alpha) is located in the stellate reticulum and its receptor, type I IL-1R (IL-1R), is present in the adjacent dental follicle. IL-1alpha may play a role in initiating tooth eruption because of its ability to enhance the gene expression in the dental follicle of putative tooth eruption molecules colony-stimulating factor-one (CSF-1). monocyte chemotactic protein-1 (MCP-1), and nuclear factor kappa B (NFkappa-B). To directly examine the effect of IL-1alpha and IL-1R on tooth eruption, we observed the times of tooth eruption in null mice devoid of the type I IL-1R gene. The results showed that the time of eruption in the null mice was delayed by 2 d for the first mandibular molar and 1 d for incisors as compared to wild type controls. Reverse transcription-polymerase chain reaction (RT-PCR) techniques confirmed the absence of the IL-1R gene in the null mice, but the genes for CSF-1 and NFkappaB were still expressed. Thus, a molecule(s) other than IL-1alpha also may enhance the expression of CSF- and NFkappaB in the dental follicle. Because there is a slight delay of tooth eruption in IL-1R null mice, IL-1alpha may normally play a role in eruption. However, eruption eventually can occur without the signaling from IL-1alpha.

Animals↗

PubMed2001

Variations in tooth preparations for resin-bonded all-ceramic crowns in general dental practice.

OBJECTIVE: To investigate variations in tooth preparations for resin-bonded all-ceramic crowns (RBCs) in general dental practice (GDP). DESIGN: Laboratory-based retrospective analysis of dies for RBCs. SETTING: General dental practices in the UK and Ireland (2000). METHODS: A sample (n = 132) of laboratory models containing 180 tooth preparations for RBCs, featuring work from different general dental practitioners was obtained from four commercial dental laboratories. Aspects of the preparations were quantified and compared with accepted criteria defined following a review of the literature. RESULTS: The teeth found to be most frequently prepared for RBCs were maxillary incisors (41%). Margin positions were variably positioned with 29% of the preparations on the buccal aspect having subgingival margins. There were many tooth preparation dies for low fusing RBCs (47%) and Chameleon Fortress RBCs (62%) demonstrating overpreparation in the mesiodistal plane. The majority of the margins (84% buccally and 79% lingually) of the dies examined exhibited appropriate shoulder or chamfer finishes. Of the Chameleon Fortress preparations analysed, 86% had been underprepared occlusally. 42% of the teeth had been prepared with no regard to tooth morphology and demonstrated just one plane of reduction. The majority (93%) of the clinicians failed to provide any information regarding the shade of the prepared tooth stump. CONCLUSIONS: On the evidence of this survey of this sample of general dental practitioners' work, it was found that relevant guidelines for the preparations of RBCs are not being fully adhered to.

Crowns↗

PubMed2005

Surface and intra-pulpal temperature rises during tooth bleaching: an in vitro study.

OBJECTIVE: To measure the surface and intra-pulpal temperature increases in vitro on upper and lower anterior teeth during tooth whitening procedures. METHOD: A thermocouple was used to measure the temperature increase on the surface of an extracted upper central incisor tooth. Intra-pulpal temperature readings were made on upper and lower central incisors, lateral incisors and canines. Four lamps recommended for tooth bleaching were tested; a plasma arc lamp, a xenon-halogen lamp, a standard halogen lamp and a diode laser lamp. Temperature measurements were made with and without the bleaching agent present on the labial tooth surface. RESULTS: The increase in surface temperature readings ranged from 0.44 degrees C (luma arch) to 86.3 degrees C (laser) with no bleaching gel present. Intra-pulpal temperature increases ranged from 0.30 degrees C to 15.96 degrees C. The presence of the bleaching gel reduced temperature increases seen at the tooth surface and within the pulp. CONCLUSIONS: The increase in the intrapulpal temperature with most bleaching lamps was below the critical threshold of a 5.50 degrees C increase thought to produce irreversible pulpal damage. The only lamp that produced an intrapulpal temperature increase above this threshold was the laser-based lamp and caution is advised when using this equipment.

Body Temperature↗

PubMed1996

The effect of acetaminophen, ibuprofen, and misoprostol on prostaglandin E2 synthesis and the degree and rate of orthodontic tooth movement.

The present study compared the effect of acetaminophen, ibuprofen and misoprostol on PGE2 synthesis and orthodontic tooth movement. Guinea pigs were randomly assigned into one of three test groups or a control group. Each group received study treatments every 12 hours as an orthodontic force was applied to the maxillary incisors. Direct linear measurements of tooth separation were recorded at days 2, 4, 6, 10, and 11, and inflammatory exudate from the periodontal ligament (PDL) space was extracted and quantitatively analyzed radioimmunologically for the presence of PGE2 at days 4 and 9. Comparing the concentration of PGE2 in sample extracts, a significant difference (P = 0.001) was found among drug groups. A highly significant difference was found between the mean tooth separation among the various drug groups (P < 0.001). At day 11 the misoprostol group exhibited 4.49 +/- 0.49 mm of separation; ibuprofen 2.56 +/- 0.11 mm, and the control and acetaminophen groups exhibited similar degrees of tooth separation: 3.31 +/- 0.07 mm and 3.31 +/- 0.08 mm, respectively. A highly significant difference occurred between the mean rates of tooth separation among the various drug groups after day 8 (P < 0.001). Results of this study suggest that acetaminophen is the analgesic of choice for the relief of minor discomfort associated with orthodontic treatment.

Acetaminophen↗

PubMed2003

Optimum force magnitude for orthodontic tooth movement: a systematic literature review.

The aim of this study was to perform a meta-analysis of the literature concerning the optimal force or range of forces for orthodontic tooth movement. Over 400 articles both on human research and animal experiments were found in Medline and by hand searching of main orthodontic and dental journals. Articles on animal experiments were in the majority. A wide range of animal species such as rat, cat, rabbit, beagle dog, monkey, mouse, and guinea pig were used. Besides variation in species, there was also a wide range of force magnitudes, teeth under study, directions of tooth movement, duration of experimental period, and force reactivation. Furthermore, hardly any experiments were reported that provide information on the relation between the velocity of tooth movement and the magnitude of the applied force. Data from human research on the efficiency of orthodontic tooth movement appeared to be very limited. The large variation in data from current literature made it impossible to perform a meta-analysis. Therefore, we have systematically reviewed the literature. It appeared that no evidence about the optimal force level in orthodontics could be extracted from literature. Well-controlled clinical studies and more standardized animal experiments in the orthodontic field are required to provide more insight into the relation between the applied force and the rate of tooth movement.

Animals↗

PubMed2003

Testing force systems and biomechanics--measured tooth movements from differential moment closing loops.

Orthodontic tooth movement can be compared to a stimulus-response model, where the stimulus is the applied force system and the response is the resulting tooth movement. Although the principles of mechanics have been applied to orthodontic appliance design, the expression of treatment responses to the force systems is less well known. The purpose of this study was to compare measured tooth movements with the theoretical force system exerted by differential moment closing loops. Sixteen subjects requiring maximum posterior anchorage control were selected to participate in this prospective investigation. T-loop springs designed to deliver a differential moment-to-force ratio to the posterior vs the anterior teeth were used. Initial cephalometric radiographs were taken with special devices attached to the molar and canine teeth to allow precise identification. Immediately after the radiograph, the T-loop archwires were inserted and activated. After an observation period of approximately 90 days, the wires were removed, devices reinserted into the molars and canines, and a second cephalometric radiograph was obtained. Superimposition techniques were used to compare the actual tooth movements. The results showed tooth movements consistent with the prescribed force system. The anterior teeth, as represented by the canines, were retracted an average of 1.73 mm, whereas the posterior anchorage (molars) moved mesially only 0.50 mm. Furthermore, the canine teeth exhibited tipping or translation, and the molars showed mesial root movement. The variability of the treatment response as a function of the stimulus (appliance design), response (biological variation), and measurement technique was described.

Adolescent↗

PubMed2005

Standardizing interarch tooth-size harmony in a Syrian population.

The Bolton analysis is considered to be a good indicator for evaluating the degree of intermaxillary tooth-size harmony, but the possibility of ethnic variation of these values should be examined. Thus, the aim of this study was to calculate both the anterior and overall ratios of mandibular and maxillary tooth sizes for a Syrian sample of harmonious permanent dentitions and to compare these ratios with the data from the Bolton and the Michigan studies. In plaster models of 55 Syrian patients (11-22 years) with neutral occlusion (Angle Class I), harmonious overjet and overbite, no reduction of mesiodistal tooth width or missing teeth, the mesiodistal widths of each tooth from the incisors to the first permanent molars were measured in both arches. In the statistical data analysis, the anterior and overall ratios were calculated according to Bolton. The results for the anterior ratio (78.99 +/- 2.18) and the overall ratio (92.26 +/- 2.06) showed no statistically significant differences by sex (P > .48). These values and the degree of variation were similar to the original data by Bolton. Both studies differed considerably from the values of the anterior ratio found in the Michigan University study, which also shows a higher degree of variability. Nevertheless, the overall ratios of all three studies were very similar. Therefore, the interarch tooth-size analysis and values for a harmonious dentition developed by Bolton can also be transferred to an Arabian or at least a Syrian population.

Adolescent↗