The effect of chlorhexidine on dental calculus formation: an in vitro study.

BACKGROUND: Chlorhexidine gluconate (CHG) has been proven to be effective in preventing and controlling biofilm formation. At the same time, an increase in calculus formation is known as one of considerable side effects. The purpose of this study was to investigate whether mineral deposition preceding a calculus formation would occur at an early stage after the use of CHG using an in vitro saliva-related biofilm model. METHODS: Biofilms were developed on the MBEC™ device in brain heart infusion (BHI) broth containing 0.5% sucrose at 37 °C for 3 days under anaerobic conditions. Biofilms were periodically exposed to 1 min applications of 0.12% CHG every 12 h and incubated for up to 2 days in BHI containing a calcifying solution. Calcium and phosphate in the biofilm were measured using atomic absorption spectrophotometry and a phosphate assay kit, respectively. Morphological structure was observed using a scanning electron microscope (SEM), and chemical composition was analyzed with an electron probe microanalyzer (EPMA). RESULTS: The concentrations of Ca and Pi following a single exposure to CHG increased significantly compared with the control. Repeatedly exposing biofilms to CHG dose-dependently increased Ca deposition, and the amount of Ca was five times as much as that of the control. Pi levels in CHG-treated biofilms were significantly higher than those from the control group (p < 0.05); however, the influence of the number of exposures was limited. Analyses using an SEM and EPMA showed many clusters containing calcium and phosphate complexes in CHG-treated biofilms. Upon composition analysis of the clusters, calcium was detected at a greater concentration than phosphate. CONCLUSIONS: Findings suggested that CHG may promote mineral uptake into the biofilm soon after its use. It is necessary to disrupt the biofilm prior to the start of a CHG mouthwash in order to reduce the side effects associated with this procedure. The management of patients is also important.

The Application of Scanning Electron Microscopy with Energy-Dispersive X-Ray Spectroscopy (SEM-EDX) in Ancient Dental Calculus for the Reconstruction of Human Habits.

The great potential of scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) is in detection of unusual chemical elements included in ancient human dental calculus to verify hypotheses about life and burial habits of historic populations and individuals. Elemental spectra were performed from archeological samples of three chosen individuals from different time periods. The unusual presence of magnesium, aluminum, and silicon in the first sample could confirm the hypothesis of high degree of dental abrasion caused by particles from grinding stones in flour. In the second sample, presence of copper could confirm that bronze jewelery could lie near the buried body. The elemental composition of the third sample with the presence of lead and copper confirms the origin of individual to Napoleonic Wars because the damage to his teeth could be explained by the systematic utilization of the teeth for the opening of paper cartridges (a charge with a dose of gunpowder and a bullet), which were used during the 18th and the 19th century AD. All these results contribute to the reconstruction of life (first and third individual) and burial (second individual) habits of historic populations and individuals.

Qualitative microanalysis of calcium local structure in tooth layers by means of micro-RRS.

The Resonant inelastic X-ray scattering or resonant Raman scattering is an inelastic process of second order that becomes important when the energy of the excitation radiation is below but close to an absorption edge. In this process, the emitted photons have a continuous energy distribution with a high energy cut-off limit. In the last few years, experiments of resonant Raman scattering has become a very powerful technique to investigate excitations of electrons in solids. A qualitative study of the calcium local structure in the different layers of teeth was carried out. In order to perform the analysis, several measurements of tooth samples were achieved using monochromatic synchrotron radiation at the XRF station of the D09B-XRF beamline at the Brazilian synchrotron facility (LNLS, Campinas), below and close to the K absorption edge of Ca to inspect the resonant Raman scattering spectra. First of all, the spectra were analyzed with specific software to fit the experimental data. After that, the residuals were determined and a fast Fourier transform smoothing procedure was applied, taking into account the instrument functions of the detecting system. These oscillations present patterns that depend of the tooth layer, i.e. of the calcium state.

[Fluorescence control of dental calculus removal].

The main condition of periodontitis prevention is the full calculus removal from the teeth surface. This procedure should be fulfilled without harming adjacent unaffected tooth tissues. Nevertheless the problem of sensitive and precise estimating of tooth-calculus interface exists and potential risk of hard tissue damage remains. In the frames of this work it was shown that fluorescence diagnostics during calculus removal can be successfully used for precise detection of tooth-calculus interface. In so doing the simple implementation of this method free from the necessity of spectrometer using can be employed. Such a simple implementation of calculus detection set-up can be aggregated with the devices of calculus removing (as ultrasonic or laser devices).

Neanderthal medics? Evidence for food, cooking, and medicinal plants entrapped in dental calculus.

Neanderthals disappeared sometime between 30,000 and 24,000 years ago. Until recently, Neanderthals were understood to have been predominantly meat-eaters; however, a growing body of evidence suggests their diet also included plants. We present the results of a study, in which sequential thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) were combined with morphological analysis of plant microfossils, to identify material entrapped in dental calculus from five Neanderthal individuals from the north Spanish site of El Sidrón. Our results provide the first molecular evidence for inhalation of wood-fire smoke and bitumen or oil shale and ingestion of a range of cooked plant foods. We also offer the first evidence for the use of medicinal plants by a Neanderthal individual. The varied use of plants that we have identified suggests that the Neanderthal occupants of El Sidrón had a sophisticated knowledge of their natural surroundings which included the ability to select and use certain plants.

[Impact of Er, Cr: YSGG-laser on the tooth root cement in the treatment of chronic periodontal disease (the results of electron microscopic studies)].

Ten teeth removed because of periodontal disease were irradiated by Er, Cr: YSGG laser (power 1W and 1,5W). Scanning electron microscopy showed the 10-second exposure of the laser beam to remove the tartar from the surface of the tooth root, as well as "smear" layer and infected cement, exposing the dentine tubules and influencing the collagen fibers, forming a rough surface of the tooth root. These data suggest the effectiveness of Er, Cr: YSGG-laser in the treatment of tooth root cement surface by periodontal disease. Er, Cr: YSGG-laser with a power of 1 and 1,5 W can be used as an adjunctive treatment mode by periodontal therapy.

Investigation into the optimum beam shape and fluence for selective ablation of dental calculus at lambda = 400 nm.

BACKGROUND AND OBJECTIVES: A frequency-doubled Ti:sapphire laser is shown to selectively ablate dental calculus. The optimal transverse shape of the laser beam, including its variability under water-cooling, is determined for selective ablation of dental calculus. STUDY DESIGN/MATERIALS AND METHODS: Intensity profiles under various water-cooling conditions were optically observed. The 400-nm laser was coupled into a multimode optical fiber using an f = 2.5-cm lens and light-shaping diffuser. Water-cooling was supplied coaxially around the fiber. Five human tooth samples (four with calculus and one pristine) were irradiated perpendicular to the tooth surface while the tooth was moved back and forth at 0.3 mm/second, varying between 20 and 180 iterations. The teeth were imaged before and after irradiation using light microscopy with a flashing blue light-emitting diode (LED). An environmental scanning electron microscope imaged each tooth after irradiation. RESULTS: High-order super-Gaussian intensity profiles are observed at the output of a fiber coiled around a 4-in. diameter drum. Super-Gaussian beams have a more-homogenous fluence distribution than Gaussian beams and have a higher energy efficiency for selective ablation. Coaxial water-cooling does not noticeably distort the intensity distribution within 1 mm from the optical fiber. In contrast, lasers focused to a Gaussian cross section (< or =50-microm diameter) without fiber propagation and cooled by a water spray are heavily distorted and may lead to variable ablation. Calculus is preferentially ablated at high fluences (> or =2 J/cm(2)); below this fluence, stalling occurs because of photo-bleaching of the calculus. Healthy dental hard tissue is not removed at fluences < or =3 J/cm(2). CONCLUSION: Supplying laser light to a tooth using an optical fiber with coaxial water-cooling is determined to be the most appropriate method when selectively removing calculus with a frequency-doubled Ti:sapphire laser. Fluences over 2 J/cm(2) are required to remove calculus efficiently since photo-bleaching stalls calculus removal below that value.

Electron microscopy of octacalcium phosphate in the dental calculus.

The purpose of this study was to morphologically demonstrate the presence of octacalcium phosphate in the dental calculus by judging from the crystal lattice image and its rapid transformation into apatite crystal, as part of our serial studies on biomineral products. We also aimed to confirm whether the physical properties of octacalcium phosphate are identical with those of the central dark lines observed in crystals of ordinary calcifying hard tissues. Electron micrographs showed that crystals of various sizes form in the dental calculus. The formation of each crystal seemed to be closely associated with the organic substance, possibly originating from degenerated microorganisms at the calcification front. Many crystals had an 8.2-A lattice interval, similar to that of an apatite crystal. Furthermore, some crystals clearly revealed an 18.7-A lattice interval and were vulnerable to electron bombardment. After electron beam exposure, this lattice interval was quickly altered to about half (i.e. 8.2 A), indicating structural conversion. Consequently, a number of apatite crystals in the dental calculus are possibly created by a conversion mechanism involving an octacalcium phosphate intermediate. However, we also concluded that the calcification process in the dental calculus is not similar to that of ordinary calcifying hard tissues.

A comparison of root surface instrumentation using two piezoelectric ultrasonic scalers and a hand scaler in vivo.

BACKGROUND AND OBJECTIVE: This study compared the effectiveness of two piezoelectric ultrasonic scalers and a hand scaler for subgingival scaling and root planing in vivo. MATERIAL AND METHODS: Fifteen patients with advanced periodontal disease and with teeth scheduled for extraction were selected for this study. Three experimental groups of 10 teeth each were treated with one of two piezoelectric ultrasonic scalers [Vector scaler and Enac scaler] or with a hand scaler. Instrumentation was continued until the root surface felt hard and smooth to an explorer tip. The root surface characteristics after instrumentation were examined using scanning electron microscopy, and the amount of remaining calculus, roughness and loss of tooth substance were estimated using the remaining calculus index and roughness loss of tooth substance index. RESULTS: The remaining calculus index did not differ significantly among the three groups. The roughness loss of tooth substance index was significantly lower for the Vector scaler and Enac scaler groups than for the hand scaler group and also differed significantly between the Vector scaler and Enac scaler groups. CONCLUSION: This study suggests that the Vector scaler produces a smooth root surface with minimal loss of tooth substance. It is a reasonable choice for gentle periodontal maintenance treatment.

[Fluoride content in supragingival dental calculus measured with X-ray microanalysis]. / Badania zawartosci fluorków w próbkach naddziaslowego kamienia nazebnego metoda mikroanalizy rentgenowskiej.

PURPOSE: Sparse reports on the composition of mineralized deposits forming in the child's oral cavity generally reveal their lower degree of mineralization. As reports on the formation of dental calculus in children are incomplete, we decided to study some conditions in which this process takes place. The aim of the study was to determine whether fluorine is present in supragingival dental calculus. We enrolled 12-year-old children (17 girls, 11 boys) living in a large city. RESULTS: X-ray microanalysis of dental calculus revealed the presence of carbon, oxygen, calcium, phosphorus, sodium, magnesium, potassium, sulphur, chlorine, silicon, and fluorine. Chemical analysis of 10 sites on each specimen showed large variations as to the number of elements found and their content. Fluorine was present in one specimen only (3.6%) at a very high concentration of 10.27%+/-1.27 (w/w). Chemical composition of mineralized dental deposits shows marked individual variability and the presence of fluorine is not a constant finding.

Ultrastructural study of calculus-enamel and calculus-root interfaces.

UNLABELLED: The attachment of dental calculus to the tooth (enamel or cementum) surface affects the ease or difficulty of its removal. Understanding the ultrastructural features of the calculus-tooth interface will help in the development of efficient strategies for efficient removal of dental calculus. OBJECTIVE: The aim of this study was to determine the ultrastructural characteristics of the calculus-tooth interface in relation to the occurrence of calculus fracture. DESIGN: Investigation of the ultrastructural characteristics of the calculus-tooth interface was made on eight human molars with mature supragingival and subgingival calculus using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and fourier transform infra-red (FT-IR) spectroscopy. RESULTS: Fractures were shown by SEM to consistently occur within the calculus itself, but not at the calculus-tooth interface. Higher magnification revealed that the enamel apatite crystals (in the case of supragingival calculus) or the cementum apatite crystals (in the case of subgingival calculus) appeared intimately connected with the calculus crystals at the calculus-enamel or calculus-cementum interface. TEM micrographs confirmed this intimate direct connection or fusion (epitaxial growth) of calculus crystals with enamel and cementum apatite crystals. FT-IR showed lower concentrations of organic phase attributed to microorganisms and higher concentrations of collagen at the calculus-cementum interface compared to that in the calculus away from the interface. CONCLUSION: Difficulty in complete calculus removal from tooth surfaces (especially from cementum or dentin) may be due in part to the intimate contact between the calculus and the tooth, due to the chemical bonding between the calculus crystals and the tooth apatite crystals and occasional fusion (i.e., epitaxial growth) of the calculus calcium phosphate crystals with the enamel, dentin or apatite crystals. This cohesive bonding results in fracture planes occurring within the calculus instead of at the calculus-tooth interface.

A preliminary investigation into the ultrastructure of dental calculus and associated bacteria.

INTRODUCTION: Though dental calculus is generally recognised as comprising mineralised bacteria, areas of non-mineralised bacteria may be present. AIM: To investigate the ultrastructure of non-decalcified young and mature supragingival calculus and subgingival calculus, and the possible presence of internal viable bacteria. MATERIALS AND METHODS: Supragingival calculus was harvested from five patients, 9-10 weeks after scaling and root debridement. Five samples of mature supragingival and subgingival calculus were taken from patients presenting with adult periodontitis. Specimens were fixed and embedded for transmission electron microscopy. RESULTS: The ultrastructure of young and mature supragingival calculus was similar with various large and small crystal types. Non-mineralised channels were observed extending into the calculus, often joining extensive lacunae, both containing intact non-mineralised coccoid and rod-shaped microorganisms. Subgingival calculus possessed more uniform mineralisation without non-mineralised channels and lacunae. CONCLUSION: Supragingival calculus contains non-mineralised areas which contain bacteria and other debris. The viability of the bacteria, and their identification could not be determined in this preliminary investigation. As viable bacteria within these lacunae may provide a source of re-infection, further work needs to be done to identify the bacteria in the lacunae, and to determine their viability.

Effects of a new ultrasonic scaler on fibroblast attachment to root surfaces: a scanning electron microscopy analysis.

OBJECTIVE: A study was conducted to examine the effectiveness of scaling and root planing using a new ultrasonic scaler (Vector). METHODS: Eighty extracted teeth affected by periodontal disease were sorted into four groups of 20, each of which was subjected to one the following procedures: use of the Vector, Vector with polish, Enac and a Gracey scaler. The time spent on cleaning was measured. Half of the sample teeth were examined at random for surface roughness, and the surface texture was evaluated by means of the Remaining Calculus Index (RCI) and the Roughness and Loss of Tooth Substance Index (RLTSI). The remaining samples were incubated in dishes with a suspension of fibroblasts. After measuring the number of attached cells, the attachment of fibroblasts was observed by scanning electron microscopy. RESULTS: The RLTSI values in the Vector and Vector with polish groups were significantly lower than those in the Enac and Gracey groups, whereas the number of attached cells in the Vector with polish group was larger than in the Enac group. Cell attachment in the Vector and Vector with polish groups proved to be better than in the Enac and Gracey groups. CONCLUSION: Since use of the Vector with polish was able to provide scaling and root planing with minimal damage and tight attachment of fibroblasts, it is suggested that this may be a useful instrument for scaling and root planing.

Er:YAG laser scaling of diseased root surfaces.

BACKGROUND: The removal of calculus and plaque is an essential component of a therapeutic approach to control periodontal disease. Er:YAG laser scaling was recently introduced as an alternative to conventional scaling procedures. In this histological study, the effects of laser instrumentation of diseased root surfaces are compared to mechanical removal of plaque and calculus with ultrasonic instruments and scalers. METHODS: Areas of subgingival calculus were identified on 40 freshly extracted human teeth. Each of these areas was randomly divided into 2 equal parts. The control site was treated either with scaling and root planing or with an ultrasonic instrument. The test site was cleaned using an Er:YAG laser according to the manufacturer's instructions. The end point of debridement was the inability to mechanically or visibly detect any remaining calculus. After pre- and postsurgical photographs and impressions for scanning electronic microscopic investigation, a plastic embedding technique was used to cut the undecalcified roots into 15 microm thick sections. RESULTS: Clinically and histologically, scaling resulted in complete debridement at all samples, producing a smooth root surface. At the test sites, laser scaling was accompanied by an increased removal of tissue and roughened surfaces. CONCLUSIONS: Laser scaling results in an increased loss of cementum and dentin, which should be taken into account in clinical situations.

Effect of an Er:YAG laser on periodontally involved root surfaces: an in vivo and in vitro SEM comparison.

BACKGROUND AND OBJECTIVE: The recently introduced Er:YAG laser seems to be a promising alternative in periodontal treatment due to its thermo-mechanical ablation mechanism. The present study attempted to compare the effects of an Er:YAG laser on periodontally involved root surfaces at different power settings in vivo and in vitro using scanning electron microscopic (SEM) observations. STUDY DESIGN/MATERIALS AND METHODS: Forty single rooted teeth (160 surfaces), with advanced periodontal destruction that were scheduled for extraction, were divided into two groups of 80 each which were treated in vivo (group A) and immediately after extraction in vitro (group B) using one of the following energy settings: 120, 140, 160, and 180 mJ at 10 Hz (71, 83, 94, and 106 J/cm(2)/pulse). The morphological changes on the treated root surfaces were evaluated using scanning electron microscopic (SEM) observations to assess the laser induced ultrastructural changes. The severity of the changes was evaluated according to an arbitrary scale in 7 degrees [1-7]. Untreated peripheral areas served as control. RESULTS: All surfaces treated in vitro (group B) showed visible crater-like defects with notch-edged borders. The depth of the surface damages varied with the power applied and was localized into cementum at energy settings of 120-160 mJ but also reached dentine at 180 mJ. Compared to that, all in vivo (group A) treated surfaces showed a homogeneous and smooth root surface morphology. The surface alterations were not related to the used energy setting. CONCLUSIONS: The results of the present study showed that the clinical use of an Er:YAG laser resulted in a smooth root surface morphology, even at higher energy settings. The results also seem to indicate that calculus removal can be selectively done in vivo.

A transmission electron microscopy study of supragingival calculus.

In this study the ultrastructure of human dental calculus was investigated using transmission electron microscopy (TEM). The aim of the study was to observe and clarify the calcification process and the part played by dental plaque in this process. Supragingival calculus from 10 patients was harvested and processed. It was shown that both calculus, and dental plaque within non-mineralised lacunae in calculus, are heterogeneous. Furthermore it was shown that the calculus/dental plaque interface was distinct, although also variable. As calcification occurred apparently independently of dental plaque in some places and when calcification of dental plaque bacteria occurred, it was also varied, it was concluded that supragingival calculus is not simply 'mineralised plaque' but a complex heterogeneous material consisting of numerous phases of mineralisation and non-mineralised areas. The role of dental plaque in the mineralisation process is unclear. However, calculus was not observed arising out of mineralising dental plaque. Mineralising dental calculus and maturing dental plaque are two distinct and different phases occurring simultaneously, albeit with great variability.

Demonstration of the central dark line in crystals of dental calculus.

Using an electron microscope and Fourier transform infrared (FTIR) microspectroscopy, we studied the lattice images of crystallites of dental calculus to demonstrate the presence of the central dark line (CDL) in its crystallite and to compare this CDL with that of bone and synthetic hydroxyapatite crystals. Ultrastructural observations revealed clearly a number of crystallites, which displayed a proper lattice image and CDL similar to that of bone, in the dental calculus. FTIR microspectroscopy revealed that the dental calculus displayed a set of major spectra analogous to that of bone. These results suggest that the formation process of hydroxyapatite crystals with CDL in dental calculus, which is considered to be an unusual type of calcified structure in association with microorganisms, is basically similar to that of the ordinary calcifying hard tissues (bone, enamel, etc.).

[Microscopic study of dental calculus in cadavers from the 18th-19th centuries]. / 18-19. századi múmiák fogköveinek mikroszkópos vizsgálata.

The authors studied the dental calculus of 20 mummies with ligth microscopy, polarized ligth microscopy and scanning electron microscopy. Gram positive bacteria could be detected in all preparates, while Gram negative bacteria in 12 and fungi only in 3 dental calculus was visible. Animal food remains within five, and plant remains in all dental calculus were identified. Anorgic element and cell debris were seen in all preparates.

The effects of a single course of a calculus-softening scaling and root planing gel. A scanning electron microscopic study.

The effect of a calculus scaling gel was evaluated as an adjunct to instrumentation in a double blind, split-mouth, clinical study. Fifteen comparable periodontally involved teeth from 5 patients were instrumented on the mesio-buccal root surface with the aid of either the test gel, placebo gel, or no gel until smoothness was achieved. Test or placebo gel was applied subgingivally for 10 minutes. Instrumentation time, ease, number of strokes, and gingival/tooth surfaces changes were recorded. Scanning electronic microscopic (SEM) evaluation of root surface topography was evaluated. The results demonstrated effective calculus removal in all treatment groups with no differences found between them. Instrumentation time, ease, and number of strokes were similar for all treatment groups. There were no harmful effects to soft or hard tissues. The results of this study do not support the use of calculus scaling gel as an adjunct to root instrumentation.

Adhesión del cálculo dental: estudio óptico y ultraestructural / Adhesion of dental calculus: an optic and ultrastructural study

Es bien conocido que el principal factor etiológico de la enfermedad periodontal es el depósito de placa bacteriana que al calcificarse da lugar a la formación del cálculo dental. El objetivo de este trabajo fue establecer con microscopía de luz, microscopía electrónica de barrido (MEB) y microscopía electrónica de transmisión (MET), cuáles son la estructuras que participan en la adhesión del cálculo a la superficie del diente. Se estudiaron 82 piezas con enfermedad periodontal avanzada, las cuales presentaban una significativa masa calcular adherida a la superficie cementaria. Las muestras se procesaron de acuerdo con las técnicas de rutina para microscopía de luz y microscopía electrónica de barrido, y la técnica de inclusión en resina Spurr para microscopía electrónica de transmisión. Al microscopio de luz se observó una delgada línea basófila de demarcación interpuesta entre el cálculo y la superficie dental. El MEB reveló la presencia de un material de naturaleza fibrilar dispuesto perpendicularmente a ambas superficies (cálculo y cemento) que actuaría como elemento responsable de tal adhesión. Al MET se comprobó que dicho material fibrilar corresponde a fibras colágenas con un patrón característico de periodicidad. En conclusión, el estudio óptico permitió el hallazgo de una zona homogénea continua en la interfase cálculo-diente. El estudio ultraestructural puso en evidencia que la íntima relación existente entre el cálculo y las irregularidades del cemento es atribuible a la firma adhesión que ofrecen las fibras colágenas entre estas dos superficies (AU)