Assessment of chewing sugar-free gums for oral debris reduction: a randomized controlled crossover clinical trial.

PURPOSE: To assess the oral debris removal efficacy of two commercial sugar-free chewing gums, based on a newly developed oral debris scoring system. METHODS: A randomized, examiner-blinded, three-arm crossover study was conducted, with a 1-week washout period between the crossover phases. 42 healthy adults were randomly assigned to sugar-free stick gum (Wrigley's Extra Freshmint), sugar-free pellet gum (Wrigley's Extra Fruit) or no-gum chewing groups. Subjects consumed a single chocolate cookie, and were examined at baseline, and at 2-, 5-, and 10-minute time points with or without gum-chewing treatment. Primary outcome measures were oral debris scores on the occlusal surface, interproximal and gingival margin areas. The entire test procedure was repeated on two subsequent visits. RESULTS: The baseline conditions in the three groups did not differ significantly. Chewing either stick gum or pellet gum resulted in significantly lower oral debris scores (P < 0.0001) compared to the control (no-gum) treatment for all intraoral sites, while no significant difference was observed between the two chewing gum groups. Intra-examiner repeatability of the new scoring criteria was high throughout the study (Kappa > 0.90).

High-resolution 3D magnetic resonance imaging and quantification of carious lesions and dental pulp in vivo.

OBJECTIVE: The purpose of the study was to assess the feasibility of MRI of three-dimensional visualization and quantification of carious lesions, as well as measurement of the distance between the lesion and dental pulp in vivo. MATERIALS AND METHODS: High-resolution 3D MRI was performed to measure seven carious lesions in vivo using gelatinous gadolinium-based oral contrast medium in combination with an intraoral radio frequency receiver coil on a clinical 1.5 T MRI scanner. Extension of the carious lesion in three spatial dimensions and the minimum distance between the lesion and dental pulp were quantified. When possible, the result was compared to an X-ray projection and an impression of the lesion taken using a plastic impression material before and after dental treatment. RESULTS: Carious lesions, including pit and fissure, approximal lesions, and occult dentin caries, could be visualized due to the MRI signal rise in the porous affected dentin. The minimum distance between the carious lesion and dental pulp could be determined in all cases. CONCLUSION: The results presented demonstrate the feasibility of high-resolution dental MRI to three-dimensionally visualize and quantify carious lesions, including approximal and occult caries lesions, and measure the minimum distance to the dental pulp.

Analysis of surface roughness and microleakage of fissure sealants following organic debris removal with Carisolv.

OBJECTIVE: The objective of the present study was to improve fissure sealing by pre-treatment with Carisolv in order to remove organic debris. The surface morphology and roughness of fissure cavities and the degree of microleakage after Carisolv application were compared with those after bristle brush treatment in vitro. METHODS: Fifty extracted human teeth were used in this study. The teeth were randomly divided into two groups of 25 each. Artificial fissures were prepared in all teeth into which artificial organic debris was placed. The debris in 25 teeth of one group was removed using Carisolv applied for 30s and excavation was performed with a dental explorer until the gel was clear. The remaining 25 teeth were then cleaned using bristle brush with prophylaxis paste. Surface roughness was analyzed in five samples from each group by color laser three-dimensional (3D) microscopy and by scanning electron microscopic examination. The remaining samples were filled with sealant and subjected to a microleakage test under thermocycling. Statistical analysis was performed using the Mann-Whitney U-test; a value of p<0.05 was considered significant. RESULTS: Morphologically, most of the debris in the fissures was removed by Carisolv treatment, whereas some fissures were not cleaned by bristle brush. Carisolv-treatment with acid-etching resulted in removal of debris-like smear layer leaving enamel prisms open, and 3D laser microscopy demonstrated that the roughness values increased after acid-etching. However, microleakage test of both Carisolv and brush methods showed similar results. CONCLUSIONS: Carisolv-treated surfaces especially when subjected to acid-etching might facilitate good adaptation of sealant to enamel, because of an increase in surface roughness and favorable surface characteristics.

Pits and fissures: etch resistance in prismless enamel walls.

BACKGROUND: In a previous study to examine the nature of etching on the walls of fissures, there was a consistent result of resistance to deep etching on parts of the walls and a zone of lesser etching on part of the walls as evidenced by the uptake of stain. The staining had been used to examine the nature of the etch pattern. The aims of this study were to define the nature of this etch resistant area. METHODS: A sample of 55 teeth, both molars and premolars, were divided into three groups. In the first group the wetting of fissures by the etchant was examined; the second group tested for the effects of pellicle-cuticle-debris or air entrapment on the etching process. The final group looked at alternative mechanical treatments of the fissure prior to etching. RESULTS: The specimens split along the fissures showed clearly that the etch resistant zone was not due to lack of contact with the etchant or the presence of a pellicle-cuticle-debris covering, but to the presence of a prismless enamel structure. This study showed that this zone inhibited tag development on the fissure walls. CONCLUSIONS: The mechanical removal of this prismless layer of enamel within the fissure system should result in an improved bonding of a fissure sealant through better tag development, in turn leading to a reduction in the failure rate of a sealant used to prevent caries.

Thickness of acquired salivary pellicle as a determinant of the sites of dental erosion.

Dental erosion shows a typical distribution pattern within the dental arches. Tooth protection from erosion by salivary pellicle has been shown in vitro, but the hypothesis that pellicle may differ quantitatively at sites of erosion has not been investigated. This study aimed to determine the thickness of acquired salivary pellicle within the dental arches, investigate the possible relationship of this thickness to the distribution and severity of erosion within the arches, and confirm the protective effect of pellicle against dental erosion. Eight enamel blocks were produced from each of 5 bovine incisors assigned to five volunteers. Each block was further cut into 2 slabs, producing control and experimental slabs. Pellicle developed on experimental slabs located on 8 intra-oral sites after 1 hr of exposure was stained by "sheep anti-human IgGAM-FITC". Slabs were then visualized, and pellicle thickness measured, by confocal laser scanning microscopy. Eroded enamel lesions were produced in experimental and control slabs by means of pure orange juice. The degree of erosion was quantified by transverse microradiography. Pellicle thickness varied significantly within the dental arches and among individuals. An inverse relationship (r = -0.96, p<0.001) was observed between the degree of erosion and pellicle thickness. Significant differences in erosion were observed between slabs with and those without pellicle. This study has shown that the thickness of acquired salivary pellicle varies within the dental arches, which may be responsible for the site-specificity of dental erosion, and that pellicle does protect the teeth from erosion.

[Morphologic characteristics of dental cuticle on teeth affected by diabetic periodontitis].

OBJECTIVE: To determine the nature of the dental cuticle found on teeth with diabetic periodontitis. METHODS: Thirteen permanent teeth which were extracted from three diabetic patients with periodontitis were studied, with the control group of 16 healthy teeth extracted for orthodontical reasons, then all the teeth were decalcified with 5% nitric acid, stained with HE, and examinated by using light microscope. RESULTS: A layer of thick coat, dental cuticle, covered the root surface of the teeth with diabetic periodontitis, and the cuticle which presented regular laminar structure extended from the cementoenamel junction to the apical portion with different thickness from 40 to 80 microns, but no such similar cuticle structure was found on the healthy teeth of the control group. CONCLUSION: There is abnormal cuticle structure on the teeth of diabetic patients with periodontitis.

Comparative in vitro effectiveness of closed root debridement with fine instruments on specific areas of mandibular first molar furcations. I. Root trunk and furcation entrance.

The purpose of this study was to compare curets with a small blade to slim ultrasonic inserts on their efficacy in removing artificial deposits from the root trunk and furcation entrance areas of mandibular molars using an in vitro model simulating a clinically closed root debridement approach. The study was conducted on 100 artificial mandibular first molars (50 right side and 50 left side) with anatomical roots. Root trunks, furcation entrances, and furcation areas of each molar were colored by a coat of black model paint. The teeth were fixed in a custom acrylic model and maintained in a firm position by modified acrylic occlusal splints. The root areas were covered with a heavy rubber dam imitating gingival tissue. The model was attached to a mannequin and mounted on a dental chair. Fifty molars (25 right, 25 left) were instrumented with the experimental curets and an equivalent number of molars with the ultrasonic inserts. The instrumentation was carried out by one experienced operator, spending 4 minutes on each molar. The instrumented areas were individually analyzed to determine the percentage of deposits remaining, using a computerized imaging routine system. One-way analysis of variance was conducted to test for differences between both types of instruments. Results revealed that the curets were significantly more efficient (P < 0.01) than the ultrasonic inserts in removing paint from both root trunks and furcation entrances. These findings should be corroborated in a clinical study to determine the potential value of the instruments tested during initial therapy or supportive care of involved mandibular furcations.

Comparative in vitro effectiveness of closed root debridement with fine instruments on specific areas of mandibular first molar furcations. II. Furcation area.

The purpose of this study was to demonstrate the extent of deposits removed from within the furcation area of mandibular first molars following the use of curets with a modified blade and slim ultrasonic inserts in an in vitro model simulating a closed root debridement approach to furcation treatment. The furcation areas of 100 artificial mandibular first molars were uniformly coated with black model paint. The molars were fixed into a custom acrylic model, maintained in a firm position with modified occlusal splints, and the roots covered with a heavy rubber dam. The model was set in a mannequin and mounted on a dental chair recreating a clinical situation. Fifty molars (25 right, 25 left) were instrumented with the experimental curets and an equivalent number of molars with the ultrasonic inserts. An experienced dental hygienist completed all the instrumentation, spending 4 minutes on each molar. The molars were sectioned buccolingually from the crown apically to separate the roots, and areas in the internal surface of mesial and distal roots were analyzed to determine the percentage of deposits remaining using a computerized imaging routine system. A 2-factor analysis of variance was conducted to test for differences between both types of instruments. The curets produced furcation root surfaces with significantly less percentage of residual deposits than the ultrasonic inserts (P < 0.01). This study indicates the potential value of small bladed curets in debriding involved furcations during initial therapy and supportive periodontal therapy. The current findings should be corroborated in a clinical study.

Contemporary interpretation of probing depth assessments: diagnostic and therapeutic implications. A literature review.

This paper addresses the diagnostic and therapeutic implications of increased probing depths. In general, in untreated and treated patients, when deep and shallow probing depths are compared, the data indicate that deep sites are associated with increased bleeding upon probing, elevated subgingival temperatures, higher levels of pathogens, more probing errors, a greater amount of infiltrated connective tissue, reduced ability to remove subgingival deposits with root planing, and diminished effectiveness of oral hygiene to alter the subgingival microbiota. Clinical trials demonstrate that probing depth is not a good predictor of future disease progression. However, deep sites are at greater risk of disease progression than shallow sites in untreated and treated patients. Furthermore, the deeper the probing depth, the greater the risk of future disease progression. Overall, the preponderance of evidence indicates that it is advantageous, but not always necessary, for patients to have shallow probing depths. With regards to surgical reduction of probing depths beyond that attained with non-surgical therapy, clinicians need to consider the advantages (e.g., ease of maintenance, reduced risk of disease progression) and disadvantages (e.g., root sensitivity, cosmetic defects) of treatment procedures. Since numerous variables require consideration (e.g., response to root planing, goals of therapy, acceptable level of risk for future disease progression), treatment decisions will vary depending on the patient and the desired clinical outcome at specific sites.

Rate of pellicle formation in vivo.

The acquired enamel pellicle is thought to be the result of a selective adsorption of salivary proteins and to be involved in the protection of the enamel surfaces. The chemical composition of the 2-h acquired enamel pellicle is fairly well established. However, the rate of formation and the amino acid composition of the initially formed enamel pellicle have been little investigated. The aim of this study was therefore to examine the rate of pellicle formation and the amino acid composition of the initially formed enamel pellicle. Samples of human enamel surfaces were carried in the mouth for various periods of time (2.5 min to 10 h). Rate of pellicle formation was indicated as a function of oral exposure time and the time necessary to remove the proteinaceous film from the surfaces by argon ion sputtering. The chemical composition of the initially acquired pellicle was examined by amino acid analyses of pellicle material collected in vivo from enamel surfaces 15 min and 1 h after pumicing, respectively. The pellicle reached an initial thickness in about 2-3 min, at which level it stayed for about 30 min. The thickness of the acquired pellicle then increased to about three times the initial thickness and stayed at that level for the rest of the experimental period (10 h). Amino acid analyses of pellicle material collected after 15 min and after 1 h were different in that the amino acid profiles of the 15-min pellicle only contained traces of proline and arginine. It may be argued that the pellicle formation proceeds in two stages owing to the adsorption of protein aggregates and that the chemical compositions of the pellicles of the two stages differ.

Gingival recession: intra-oral distribution and associated factors.

This study assesses the role of poor oral hygiene and forceful toothbrushing as risk factors for recession. As part of a cross-sectional root surface caries study, 298 subjects, 42 to 67 years of age, with at least one exposed root surface, were examined. Since 66% of the root surface exposure and practically all the abrasion was on buccal surfaces, the analyses focused only on the buccal surface. Analysis of variance on subject means for buccal recession showed both calculus and presence of buccal root surfaces with abrasion to be significantly associated with recession after adjusting for age and gender. Root surface abrasion was considered a surrogate variable for forceful brushing. An additional analysis utilized means for each tooth, aggregating across subjects. For each of the 32 tooth types mean buccal recession, percent of exposed root surfaces with abrasion (%ra), and mean debris and calculus scores were calculated. Partial correlation coefficients across tooth types between recession and calculus, adjusting for abrasion, and for recession and abrasion adjusting for calculus, were 0.55. Interpretation of the %ra as a crude measure of forceful brushing is supported by its strong negative correlation across tooth types, with mean debris (r = -0.8) and mean calculus (r = -0.7). Separate analyses on premolars and on molars suggested that recession on premolars may be primarily due to brushing force and on the molars may be primarily due to debris and calculus. The findings suggest that recession is positively associated with percent abrasion (reflecting forceful brushing) and with poor oral hygiene.

Brushing-induced effects with and without a non-fluoride abrasive dentifrice on remineralization of enamel surfaces etched with phosphoric acid.

The remineralization of acid-etched enamel after brushing with and without a non-fluoride abrasive dentifrice was investigated using scanning electron microscopy after sodium hypochlorite (NaOCl) or ethylenediamine tetra-acetic acid treatment, of the specimens. Ground enamel pieces were etched with 30% phosphoric acid for 60 s and attached to resin plates. They were exposed to the oral environment of 4 subjects for 8 weeks and brushed for 1 min daily. Paste and brushing caused the acid-etched enamel to erode selectively, i.e., deep grooves were formed in the prism peripheral regions, while projections of the prism bodies showing a relatively low density of crystallites were retained. Brushing without dentifrice, on the other hand, caused about 0.5 micron thick pellicle with tag-like structures to cover the etched enamel. Fine mineral granules, presumably derived from saliva and minute fragments of etched crystallites, were precipitated on the enamel surface as a thin layer with the pellicle. These results indicate that daily brushing without dentifrice induces the remineralization of acid-etched enamel by depositing salivary components, while paste brushing will lead to abrasion of the weakened enamel.

Cleaning effect of toothbrushing with three different toothpastes and water.

The cleaning effect of three different toothpastes and water was studied in vivo using a laser reflexion technique. Ten healthy persons formed the test group. Light reflexion measurements on the upper front teeth were performed before and after the removal of a 72-hour plaque-pellicle. The results suggest that the toothpaste containing sodium bicarbonate as abrasive was less effective than a toothpaste containing aluminium silicate, calcium carbonate and dicalcium-phosphate dihydrate or silicon dioxide and dicalcium phosphate dihydrate. The abrasivity of the toothpastes was compared in vitro. The in vitro results correspond quite well to the in vivo findings.

Acid resistance of human enamel by brushing with and without abrasive dentifrice.

Daily brushing with and without abrasive dentifrice pieces of was performed on the ground surfaces of human enamel attached to resin plates which were exposed to the oral cavities of 4 subjects for 8 weeks. The difference in acid resistance between a pair of enamel pieces obtained from the same tooth was examined with atomic absorption spectrometry. After etching with a lactate buffer solution at pH 4.5, the amount of Ca dissolved from the enamel in each pair by brushing without dentifrice was significantly lower than that when brushing with an by abrasive paste. Under SEM, the brushing with paste caused prism structures to appear clearly on the enamel surface, while brushing without dentifrice caused a nonbacterial organic film, i.e., salivary pellicle, to cover the surface. These results indicate that the pellicle is protected by mineral deposits when brushing without dentifrice but brushing with an abrasive paste tears off the unmineralized pellicle. Brushing without dentifrice induces a stronger resistance to acid on the enamel surface.

Rat palatal histology related to denture-like appliances.

Two designs of palatal denture-like appliance were fitted to rats. Tooth- and tissue-borne appliances caused changes in epithelial thickness and keratin thickness, but these varied with anatomical site and type of appliance. A single inoculation of Candida albicans at the time of insertion of the appliance failed to establish infection consistently. Debris accumulation under the appliances was a problem which will restrict long-term studies with this model.

Patterns of de novo plaque formation in the human dentition.

The objective of the present clinical trial was to carefully assess the pattern of de novo plaque formation in the human dentition. 10 subjects aged 24-29 years were recruited for the study. None of the participants showed signs of destructive periodontitis. At the start of the preparatory period, they were given a thorough dental prophylaxis and oral hygiene instruction. For the next 2 weeks, the participants were carefully monitored and 1 x every 2 days examined with respect to plaque and gingivitis. At the re-examinations, they were also given professional tooth cleaning and instruction in proper plaque control measures. Towards the end of this 2-week period, the Day 0 examination was performed which revealed that the gingival tissues of all participants were in excellent clinical health. Following the Day 0 examination, all 10 subjects were exposed to professional tooth cleaning. During the next 14 days, they abolished all mechanical tooth cleaning efforts but were examined with respect to plaque on Days 1, 4, 7 and 14. The amount of plaque formed was examined using the criteria of the Plaque Index system (PlI). Each of 6 surfaces of each tooth in the dentition was given a score from 0 to 3. The results from the re-examinations demonstrated that in humans with clean teeth and normal gingiva, the abolishment of mechanical tooth cleaning rapidly resulted in de novo plaque formation. Most plaque, as assessed by the plaque index system, formed during the first 4 days of no tooth cleaning after which moderate additional amounts of plaque formed. It was observed that the mean PlI values for individuals, for groups of teeth and tooth surfaces, provide a proper overall estimation of plaque build up. The dynamics of plaque formation between examinations and in different parts of the dentition were more easily disclosed by the data describing % distributions of different score categories and the transition between scores from one examination to the next. The total amount of plaque formed on various tooth surfaces was best presented by so called "plaque pattern displays". The results also revealed that (i) the mandibular dentition harbored more plaque than the maxillary dentition, (ii) there was a difference in the mean PlI scores between the molar and the anterior tooth regions in the maxilla, but in the mandible such a difference could not be observed (except on Day 1), (iii) plaque accumulated most at the approximal surfaces and least at the palatal surfaces, and that (iv) differences in PlI scores between groups of teeth and tooth surfaces observed on Day 4 persisted through the Day 14 examination.

Chemical analysis and scanning electron microscopy of acquired pellicle formed in vivo on stannous fluoride treated enamel.

Stannous fluoride (SnF2) has been shown to be an effective caries preventive agent. After topical treatment of enamel surfaces, two reaction products have been demonstrated to precipitate on the surfaces, a larger type of globules, probably a calcium fluoride like product, and a smaller type of globules, probably a tin phosphate. The aim of the present study was to examine the amino acid composition and the formation of the acquired pellicle on SnF2-treated enamel in vivo. The chemical composition was examined by amino acid analysis of pellicle material collected in vivo from SnF2-treated enamel surfaces. Pellicle formation was examined by scanning electron microscopy on SnF2-treated enamel fragments carried in the mouth for 2 h. The results showed that pellicle material was formed in abundant amounts and covered the globular surfaces following the SnF2 treatment. The chemical analyses showed amino acid profiles with high content of acidic and neutral amino acids. The profiles were different from known amino acid profiles obtained from analyses of pellicle material collected from untreated enamel surfaces.

Plaque accumulation on glass ionomer filling materials.

It has been suggested that fluoride released by glass ionomers inhibits the growth of plaque. The aim of this study was to compare plaque accumulation on glass ionomers and composite. The materials tested were (1) freshly mixed glass ionomer (Ketac-Fil), (2) artificially aged glass ionomer (Ketac-Fil), (3) freshly mixed silver glass ionomer (Ketac-Silver) and (4) light-cured hybrid composite (Valux). Ten volunteers wore an acrylic appliance for three periods of 18 hours, one for each glass ionomer. A glass ionomer disk was inserted on one randomly chosen side of the appliance and the composite disk on the other. The volunteers rinsed once an hour with a 15% sucrose solution. The amount of pellicle and plaque on the disk was estimated by analysing its protein content. During each cycle, more plaque accumulated on the glass ionomers than on the composite (fresh Ketac-Fil/Valux p less than 0.05, aged Ketac-Fil/Valux p less than 0.01, Ketac-Silver/Valux NS). On examination using a scanning electron microscope the surfaces of the glass ionomers were found to be markedly more porous, and to contain more microbes, than the composite surface. The presence of silver in the silver glass ionomers may have affected the initial adherence of bacteria.

Effect of silicone oil on protein adsorption to hydroxyapatite in vitro and on pellicle formation in vivo.

Silicone oil has been introduced in a dentifrice for smokers because of its effect as a polishing agent. Silicone oils are hydrophobic in character and have low surface tensions and good wetting properties. Due to the low surface tension, silicone oils may spread readily on solid surfaces and cover them with a thin, water-repellent film. Introduced via dentifrices silicone oil may thus well be able to adsorb to enamel surfaces and to interfere with surface characteristics such as protein adsorption. The aim of the present study was to examine the effect of silicone oil on protein adsorption to hydroxyapatite (HA) in vitro and on pellicle formation in vivo. The effect on protein adsorption to HA in vitro was studied by adsorption of albumin to either untreated or silicone oil treated HA powders. Ion exchange chromatography was also used with either untreated or silicone oil treated HA as bed materials. The effect on pellicle formation in vivo was studied using enamel fragments carried in the mouth to acquire pellicle material. The chemical composition of the acquired pellicle was studied by collection and chemical analysis of pellicle material formed on enamel surfaces in vivo. The study showed that silicone oil treated HA took up less protein and that the adsorbed protein was bound to hydroxyapatite by a different mechanism as compared to untreated controls. The results indicated that hydrophobic interactions could be involved in binding of proteins to silicone oil treated hydroxyapatite. Silicone oil treated enamel fragments carried in the mouth showed a slower rate of pellicle formation as compared to untreated fragments. The amino acid composition of the acquired pellicle collected in vivo from silicone oil treated enamel surfaces was also different from pellicle material collected from untreated enamel.

Morphologic and histochemical characteristics of the dental cuticle in teeth affected by prepubertal periodontitis.

A study was undertaken to determine the nature and composition of the cuticle found in teeth with generalized prepubertal periodontitis (PP). This was accomplished by using histological and histochemical methods on decalcified specimens. Forty-six permanent teeth which were extracted from three prepubertal periodontitis patients (siblings) were used. Nineteen of the 46 teeth were obtained with the facial or interdental gingiva. As a control, 20 healthy teeth extracted from 10 children for orthodontics reasons, and 22 teeth affected by terminal adult periodontitis (AP), were used. All the teeth with PP showed a thick coat covering the root surface from the cemento-enamel junction to the junctional epithelium. In some teeth the cuticle extended a few microns coronally to the cemento-enamel junction. The cuticle had a thickness which varied between 10 to 80 microns. It usually presented a very regular surface in the coronal portion of the root, and showed laminations suggesting appositional growth. In the middle and apical portions of the root exposed to the pocket, the cuticle was lobular with a very irregular surface and was covered with a thick microbial plaque. The staining reactions indicated that the cuticle was made of proteins probably derived from the inflammatory exudate. None of the healthy teeth examined nor those affected by AP showed a cuticle similar to those with PP. The cuticle formed on the teeth with PP appears to be an abnormal structure of proteinaceous nature, characteristic of these teeth, and may possibly play a role in the pathogenesis of the disease.