The effect of periodontal status and occlusal support on masticatory performance: the Suita study.

AIM: In this study, we investigated the effect of differences in periodontal status in the masticatory performance of dentate subjects with the same occlusal supporting area. MATERIALS AND METHODS: The subjects of the analysis were classified into those of Eichner A1-3 (n = 1094) and Eichner B1-4 (n = 529). Subjects' periodontal status was evaluated on the basis of the Community Periodontal Index (CPI). The number of functional teeth and occlusal support were investigated, the latter on the basis of the Eichner Index. Furthermore, masticatory performance was investigated by means of test gummy jelly. For each group, periodontal status was classified in two different ways, either with/without moderate periodontitis (CPI Code ≤2/≥3) or with/without severe periodontitis (CPI Code ≤3/4), and masticatory performance was compared between the various groups. RESULTS: In subjects who were Eichner A1 and B3, masticatory performance was significantly lower in subjects with moderate periodontitis compared with those without, and in subjects with severe periodontitis compared with those without. CONCLUSION: Periodontal disease affects masticatory performance not only if occlusion is established by natural dentition with no tooth loss but also if occlusal support has decreased.

Dental calculus formation in children and adolescents undergoing hemodialysis.

BACKGROUND: This study aimed to determine whether dental calculus formation is really higher among patients with chronic kidney disease undergoing hemodialysis than among controls. Furthermore, the study evaluated correlations between dental calculus formation and dental plaque, variables that are related to renal disease and/or saliva composition. METHODS: The Renal Group was composed of 30 patients undergoing hemodialysis, whereas the Healthy Group had 30 clinically healthy patients. Stimulated whole saliva and parotid saliva were collected. Salivary flow rate and calcium and phosphate concentrations were determined. In the Renal Group the saliva collection was carried out before and after a hemodialysis session. Patients from both groups received intraoral exams, oral hygiene instructions, and dental scaling. Three months later, the dental calculus was measured by the Volpe-Manhold method to determine the rate of dental calculus formation. RESULTS: The Renal Group presented a higher rate of dental calculus formation (p < 0.01). Correlation was observed between rate of dental calculus formation and whole saliva flow rate in the Renal Group after a hemodialysis session (r = 0.44, p < 0.05). The presence of dental calculus was associated with phosphate concentration in whole saliva from the Renal Group (p < 0.05). CONCLUSION: In conclusion, patients undergoing hemodialysis presented accelerated dental calculus formation, probably due to salivary variables.

Hormonal influence on the physiology and pathology of the dental gingival unit: the preliminary results of a pilot study.

AIM: The effects of steroid hormones on the periodontium are most prominent at certain stages of a woman's life especially during the menstrual cycle when there is an increase in the secretion of sex hormones or a significant fluctuation in their concentration. The deterioration of existing periodontal conditions can be attributed to a fluctuation in the steroid hormones in circulation. By contributing to our understanding of periodontal changes caused by variation in hormone concentrations, this study aims to encourage the implementation in dental practice of the most suitable forms of treatment for hormone-related pathologies. METHODS: Tartar was removed from the teeth of five young women and four biopsies and blood tests were carried out on them at regular intervals. The information gathered was used to monitor periodontal changes arising from variation in hormone concentrations. RESULTS: The histological analysis of the test samples under an optical microscope did not reveal signs of inflammation, hyperaemia or oedema at any stage of the menstrual cycle in the patients examined. The extent of gingival Keratinization was found to be comparable to that present in the follicular phase. CONCLUSION: The occurrence of ovulation could not be shown in the pilot study. The histological analysis and the analysis of hormone concentrations show primarily the absence of surges in estradiol and LH which normally accompany ovulation; the levels recorded are similar to those found in the follicular phase.

No alteration in bone mineral density in patients with periodontitis.

Alveolar bone destruction can be magnified in the presence of generalized skeletal disorders. We questioned whether severe generalized periodontitis patients display signs of bone metabolism disturbances. Our objective was to assess skeletal bone mineral density (BMD) and biochemical bone parameters in premenopausal women with periodontitis. Forty-five patients and 40 control individuals were included in the study. We measured BMD by dual-energy x-ray absorptiometry. The results showed no difference in BMD values between the periodontitis and control groups (p > 0.05). A positive relationship between the clinical attachment level and Body Mass Index (BMI) scores was observed (p = 0.03). Increased serum creatinine levels were noted in the periodontitis group (p = 0.04). Analysis of the data suggests that there is no evidence for an association between skeletal BMD and severe periodontitis in premenopausal women. There may be a link between elevated creatinine levels and periodontitis. The persons with high BMI scores seemed to be at risk for periodontitis.

A grazing Gomphotherium in Middle Miocene Central Asia, 10 million years prior to the origin of the Elephantidae.

Feeding preference of fossil herbivorous mammals, concerning the coevolution of mammalian and floral ecosystems, has become of key research interest. In this paper, phytoliths in dental calculus from two gomphotheriid proboscideans of the middle Miocene Junggar Basin, Central Asia, have been identified, suggesting that Gomphotherium connexum was a mixed feeder, while the phytoliths from G. steinheimense indicates grazing preference. This is the earliest-known proboscidean with a predominantly grazing habit. These results are further confirmed by microwear and isotope analyses. Pollen record reveals an open steppic environment with few trees, indicating an early aridity phase in the Asian interior during the Mid-Miocene Climate Optimum, which might urge a diet remodeling of G. steinheimense. Morphological and cladistic analyses show that G. steinheimense comprises the sister taxon of tetralophodont gomphotheres, which were believed to be the general ancestral stock of derived "true elephantids"; whereas G. connexum represents a more conservative lineage in both feeding behavior and tooth morphology, which subsequently became completely extinct. Therefore, grazing by G. steinheimense may have acted as a behavior preadaptive for aridity, and allowing its lineage evolving new morphological features for surviving later in time. This study displays an interesting example of behavioral adaptation prior to morphological modification.

Gingivitis susceptibility and its relation to periodontitis in men.

The objective of this cross-sectional study was to evaluate whether gingivitis susceptibility is associated with periodontitis. We analyzed data of 462 men in the VA Dental Longitudinal Study aged 47 to 92 years who had never smoked or had quit smoking 5+ years previously. Multiple logistic regression models, with tooth-level bleeding on probing at sites with attachment loss

Why does supragingival calculus form preferentially on the lingual surface of the 6 lower anterior teeth?

Many authors have assumed that the reason supragingival calculus tends to form preferentially on the lingual surface of the 6 lower anterior teeth is because saliva from the adjacent submandibular ducts is a source of calcium and phosphate ions and because loss of CO2 as the saliva enters the mouth increases the local pH. However, the fluid phase of plaque in all locations is supersaturated with respect to the calcium phosphates in calculus and there is always a tendency for calculus to deposit, except after sugar consumption, when plaque pH may fall below the critical level and the plaque fluid becomes unsaturated. pH is least likely to fall below the critical level in plaque lingual to the lower anterior teeth, as this plaque is very thin, sugar concentration after sugar intake is lowest in that area and its clearance rate is fastest, and the high salivary film velocity there promotes loss of any acid formed in plaque. A high salivary film velocity also brings more salivary urea to the site, which facilitates plaque alkalinization. These factors all contribute to the development of shallow Stephan curves of short duration and together provide a more reasonable explanation for the fact that supragingival calculus deposition progresses most easily on the lingual surface of the lower anterior teeth.

Dental Calculus Stimulates Interleukin-1ß Secretion by Activating NLRP3 Inflammasome in Human and Mouse Phagocytes.

Dental calculus is a mineralized deposit associated with periodontitis. The bacterial components contained in dental calculus can be recognized by host immune sensors, such as Toll-like receptors (TLRs), and induce transcription of proinflammatory cytokines, such as IL-1ß. Studies have shown that cellular uptake of crystalline particles may trigger NLRP3 inflammasome activation, leading to the cleavage of the IL-1ß precursor to its mature form. Phagocytosis of dental calculus in the periodontal pocket may therefore lead to the secretion of IL-1ß, promoting inflammatory responses in periodontal tissues. However, the capacity of dental calculus to induce IL-1ß secretion in human phagocytes has not been explored. To study this, we stimulated human polymorphonuclear leukocytes (PMNs) and peripheral blood mononuclear cells (PBMCs) with dental calculus collected from periodontitis patients, and measured IL-1ß secretion by ELISA. We found that calculus induced IL-1ß secretion in both human PMNs and PBMCs. Calculus also induced IL-1ß in macrophages from wild-type mice, but not in macrophages from NLRP3- and ASC-deficient mice, indicating the involvement of NLRP3 and ASC. IL-1ß induction was inhibited by polymyxin B, suggesting that LPS is one of the components of calculus that induces pro-IL-1ß transcription. To analyze the effect of the inorganic structure, we baked calculus at 250°C for 1 h. This baked calculus failed to induce pro-IL-1ß transcription. However, it did induce IL-1ß secretion in lipid A-primed cells, indicating that the crystalline structure of calculus induces inflammasome activation. Furthermore, hydroxyapatite crystals, a component of dental calculus, induced IL-1ß in mouse macrophages, and baked calculus induced IL-1ß in lipid A-primed human PMNs and PBMCs. These results indicate that dental calculus stimulates IL-1ß secretion via NLRP3 inflammasome in human and mouse phagocytes, and that the crystalline structure has a partial role in the activation of NLRP3 inflammasome.

Patients with dental calculus have increased saliva and gingival crevicular fluid fetuin-A levels but no association with fetuin-A polymorphisms.

Fetuin-A is a potent inhibitor of calcium-phosphate precipitation and of the calcification process, therefore it can also be related with dental calculus. Thus, we aimed to investigate a possible relationship between fetuin-A gene polymorphism and the presence of dental calculus. A possible relationship between serum, saliva and gingival crevicular fluid (GCF) levels of fetuin-A was also investigated. Fetuin-A c.742C > T and c.766C > G polymorphisms were investigated in 103 patients with or without dental calculus. Additionally, serum, saliva and GCF fetuin-A levels of patients were compared according to dental calculus presence. A significant difference was not observed in the distribution of the fetuin-A c.742C > T and c.766C > G polymorphisms between patients with or without dental calculus. Saliva and GCF fetuin-A concentrations of patients with dental calculus were statistically higher than those without dental calculus (P=0.001, P=0.036 respectively). According to our results, fetuin-A c.742C > T and c.766C > G polymorphisms were not associated with presence of dental calculus. However, higher GCF and saliva fetuin-A levels were detected in patients with dental calculus than in patients without dental calculus, which may result from an adaptive mechanism to inhibit mineral precipitation and eventually calculus formation.

Fluorescence properties of human teeth and dental calculus for clinical applications.

Fluorescent emission of human teeth and dental calculus is important for the esthetic rehabilitation of teeth, diagnosis of dental caries, and detection of dental calculus. The purposes of this review were to summarize the fluorescence and phosphorescence of human teeth by ambient ultraviolet (UV) light, to investigate the clinically relevant fluorescence measurement methods in dentistry, and to review the fluorescence of teeth and dental calculus by specific wavelength light. Dentine was three times more phosphorescent than enamel. When exposed to light sources containing UV components, the fluorescence of human teeth gives them the quality of vitality, and fluorescent emission with a peak of 440 nm is observed. Esthetic restorative materials should have fluorescence properties similar to those of natural teeth. Based on the fluorescence of teeth and restorative materials as determined with a spectrophotometer, a fluorescence parameter was defined. As to the fluorescence spectra by a specific wavelength, varied wavelengths were investigated for clinical applications, and several methods for the diagnosis of dental caries and the detection of dental calculus were developed. Since fluorescent properties of dental hard tissues have been used and would be expanded in diverse fields of clinical practice, these properties should be investigated further, embracing newly developed optical techniques.

Relation between the presence of supragingival calculus and protease activity in dental plaque.

Protease activity was measured in dental plaque collected from patients with or without supragingival calculus. Plaque specimens from the calculus group showed significantly greater protease activity in the presence of 0.05% sodium thioglycollate than did those from the non-calculus group. No significant difference between the two groups was observed in the protease activity without sodium thioglycollate. There was no significant correlation between the age of the patients and the protease activity.

Enamel apatite nucleation and crystal growth.

The course of enamel remineralization in aqueous solution is markedly dependent upon factors such as ionic medium supersaturation, pH, ionic strength, and the relative concentration of mineralizing surface. Although numerous attempts have been made to determine the mechanism of both the spontaneous and seeded precipitation reactions, it is only recently, through the use of a constant solution composition technique, that quantitative information can be obtained concerning the intermediate calcium phosphate phases which are formed during mineralization. Studies of surface phases in the presence of potential anti-calculus and anti-caries agents are facilitated using this approach.

Measurement of dietary and dentifrice effects upon calculus accumulation rates in the domestic ferret.

Most animal models for the study of calculus accumulation and control currently use rodents or dogs. In an effort to overcome limitations inherent in the use of these species, we investigated calculus formation in domestic ferrets, a species used by King et al. in the 1940's and 1950's. Ferrets are much smaller than dogs, and, unlike rodents, can be scored while alive. In this study, we examined the kinetics of calculus formation in female ferrets fed with moist canned cat food--either plain or supplemented with sucrose--and two combinations of mineral salts. An additional group given supplemented cat food was treated twice daily with regular Crest toothpaste. Animals were sedated with a 1:1 mixture of ketamine and xylazine solutions and given a mechanical prophylaxis prior to the trial period, then scored for area and extent of calculus accumulation at two, four, six, and eight weeks thereafter. The data showed that the mineral-supplemented groups accumulated calculus at a significantly faster rate than the unsupplemented or dentifrice-treated groups, but the differences were no longer significant at eight weeks. This demonstrated that the ferret is a suitable model for the study of calculus, that dietary mineral content influenced calculogenesis, and that the application of regular dentifrice initially slowed, but did not prevent, calculus accumulation.

In vivo remineralization of human enamel and dental calculus formation.

The aim of this investigation was to determine the inorganic composition and the surface morphology of remineralized enamel areas and of dental calculus in heavy-calculus-formers (five subjects) and to compare these results with those of non-calculus-formers (two subjects). Electron probe micro-analysis (EPMA) was carried out on sound, acid-etched, and in vivo remineralized enamel samples from heavy- and non-calculus-formers. The mean values of Ca, P, Na, Mg, Al, Si, S, Cl, and K were compared with the SEM morphology. EPMA measurements showed no significant differences in the Ca/P ratio of the surface layers of prism-oriented and/or homogeneous enamel remineralization. The variations of remineralization pattern after acid-etching are similar in teeth from heavy dental-calculus-forming patients and in teeth from non-calculus-formers. The SEM appearances of remineralized areas and of the inner surface of mature dental calculus must be considered to be totally different. The experiments carried out suggest that the remineralization of enamel is not related to the formation of calculus.

Evaluation of 2-phosphono-butane 1,2,4 tricarboxylate as a crystal growth inhibitor in vitro and in vivo.

The inhibitory activity of 2-phosphono-butane 1,2,4 tricarboxylic acid (PBTA) in the formation of hydroxyapatite (HA) was studied in vitro and in vivo. PBTA, at 4 ppm, inhibited the spontaneous formation of HA in vitro from a supersaturated solution. PBTA, at 2 ppm, completely inhibited the crystal growth of HA; at lower concentrations, a direct relationship was found between the reduction of the initial precipitation rates and PBTA concentrations in the solution. The effects of PBTA on human dental enamel in vitro were also evaluated at pH 5.0 and 7.5. Equimolar levels of EDTA served as the controls. In comparison with EDTA, the dissolution of enamel induced by PBTA was negligible. One percent solution of PBTA was evaluated in a rat calculus assay. In comparison with a placebo solution, it significantly (p = 0.05) reduced calculus formation when applied topically. It was also tested against calculus formation in beagle dogs. A topical application once a day of a 1% solution at pH 7.0 reduced calculus formation by 84% for 16 weeks. Analysis of these data suggests that the agent effectively reduces calculus formation in vivo.

Calculus attachment. Review of the literature and new findings.

This study was undertaken in order to provide current information relative to the modes of calculus attachment to tooth surfaces. A total of 63 freshly extracted teeth were fixed, sectioned, and conventionally prepared for light, transmission electron, and scanning electron microscopic examination. Previously reported histologic findings of cuticular attachment, mechanical locking into undercuts, and direct attachment of calculus matrix to the tooth surface were affirmed. The claim of bacterial penetration as a mode of attachment has been rejected. Ultrastructural evidence of cuticular attachment has been presented for the first time via a series of scanning electron micrographs. The most frequently encountered method of attachment was found to be the apparent melding of calculus matrix to the surface of cementum. In many instances, these two substances were virtually indistinguishable.

The effect of retained subgingival calculus on healing after flap surgery.

This study investigated the effects of retained subgingival calculus on healing of the periodontium at ten, 30 and 120 days. Eight beagle dogs between eight and ten years old with naturally occurring periodontal disease were used. One dog that died before any procedures were done provided information on the extent of gingival inflammation prior to surgery. Quadrants from seven dogs meeting the criteria for inclusion were selected, and each quadrant was randomly designated as either an instrumented or noninstrumented, surgical site. The gingival index for the selected sites was recorded along with clinical probing measurements. Instrumented sites were treated by reflection of a facial mucoperiosteal flap followed by thorough root planing. Non instrumented sites were treated by a facial mucoperiosteal flap alone. All flaps were returned to their preoperative position and secured with interrupted sutures. No antibiotics were given. Meticulous daily plaque control was begun the day after surgery and continued until sacrifice. There was a statistically significant reduction in gingival index scores for the 30- and 120-day instrumented sites and for the 120-day noninstrumented sites. Mean probing depths for the instrumented group showed a significant reduction at 30 and 120 days and for the noninstrumented group at 120 days after surgery. Forty percent of the noninstrumented roots and 10% of the instrumented roots displayed subgingival calculus. At all evaluation periods and in both instrumented and noninstrumented roots, inflammation was more intense when calculus was present; the difference was significant at ten days with the instrumented and at ten and 30 days with the noninstrumented specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Six-year progression of destructive periodontal disease in 2 subgroups of elderly Chinese.

Two groups of elderly chinese were selected from a large epidemiological sample on the basis of a low ("best" group) or a high ("worst" group) number of sites with attachment loss levels > or = 6 mm and/or pocket depth > or = 4 mm and at least 16 teeth present. Six years later the patients were clinically reexamined and the subgingival microflora was assessed. This paper presents the clinical characteristics of destructive periodontal disease progression among the two subgroups. The "best" group lost an average of 1.8 teeth, contrasting the average loss of 5.3 teeth among the "worst" group. Virtually all teeth lost among the "worst" group had a baseline attachment loss level > or = 4 mm, in contrast to 48% among the "best" group. While dental caries could be identified as a cause of tooth loss in both groups, the excess tooth loss among the "worst" group seems attributable to periodontal destruction. The average of 1.21 mm attachment/site lost among the "best" group was not statistically significantly different from the 1.36 mm/site lost among the "worst" group during the 6 years. Individual mean losses of attachment ranged from a gain of 0.03 mm to a loss of 3.19 mm. An attachment loss > or = 2 mm at a site was highly positively associated with a high initial attachment loss level (> or = 4 mm) at that site among the "best" group, whereas a highly negative association was seen among the "worst" group.(ABSTRACT TRUNCATED AT 250 WORDS)

The relationship between first presentation and subsequent observations in heavy calculus formers.

There are few studies that provide information on the natural history of calculus formation. The purpose of this study is to evaluate the relationship between pre-scaling baseline calculus scores, the time since the last prophylaxis before baseline, and scores 8 weeks after scaling in a group of presumed heavy calculus formers. Scaling and polishing were completed on 203 subjects with Volpe-Manhold Index (VMI) calculus scores of 7 or higher, and the date of the last prophylaxis was noted. All were re-examined after 3 weeks. The group included 45.8% males and 54.2% females; the mean age was 41.74 (range = 24 to 72). Racial mix was 57.6% African-American, 39.9% white, and 2.5% other. The mean baseline VMI score was 24.07 (SD = 15.38, range = 7-97). The VMI scores were directly related (P = < .001) to the date of the last scaling and were highest in subjects whose last scaling was more than 2 years earlier (33.67) and least in subjects whose last scaling was less than 6 months previous (15.12). At 8 weeks the mean VMI score was 9.96 (SD = 7.30; range = 0-41). The VMI scores at this time were inversely related (P = < .05) to the date of the last scaling before baseline and were lowest in subjects whose last scaling was more than 2 years earlier (9.07) and highest in subjects with the last scaling less than 6 months previous to baseline (13.07).(ABSTRACT TRUNCATED AT 250 WORDS)

Cell and fiber attachment to demineralized dentin from periodontitis-affected root surfaces.

This study assessed connective tissue and epithelial responses to dentin specimens obtained from periodontitis-affected roots of human teeth after surface demineralization. Rectangular dentin specimens with opposite faces of root and pulpal dentin were prepared from beneath root surfaces covered by sheets of calculus. One half of the specimens were treated with citric acid, pH 1, for 3 minutes, while the remainder served as untreated controls. Specimens were implanted vertically into incisional wounds on the dorsal surface of rats with one end of the implant protruding through the skin. Four specimens in each group were available 1, 3, 5 and 10 days after implantation. Histologic and histometric analyses included counts of adhering cells, evaluation of attached connective tissue fiber density and diameter, and assessment of epithelial migration. Analyses within each group comparing root and pulpal surfaces showed no differences between any of the parameters. Comparisons between experimental and control groups showed that demineralized surfaces had a greater number of cells attached, fiber attachment occurred and epithelial downgrowth was inhibited. Surface demineralization of dentin from periodontitis-affected roots predisposed toward a connective tissue attachment.