Background: Caries is a bacterial infection driven by a dysbiotic biofilm enriched and fueled by sugar. Frequent consumption of sugar can impart negative health effects, including caries; thus, there is increased interest in identifying less cariogenic sugar substitutes. In this study, the authors investigated the in vitro pH shift by Streptococcus mutans planktonic cells in the presence of various sugars and sugar substitutes. Methods: S mutans UA159 cells were suspended in a potassium chloride and magnesium chloride salt solution, and acidogenesis was determined by pH drop assay after the additions of sugars (sucrose, glucose, fructose) or sugar substitutes (allulose, sucralose, xylitol). The pH of S mutans cell suspensions was recorded at 10-minute intervals for 1 hour. Planktonic cells were then challenged with glucose and pH was monitored for an additional hour. Results: All sugars resulted in an initial pH drop to 3.5. For xylitol and sucralose, the pH drop was minimal. Allulose initially dropped to a pH of 5.4 before leveling to 5.7. In subsequent glucose challenges, all S mutans cell suspensions with sugar substitutes dropped to pH 3.5. Conclusions: Allulose, sucralose, and xylitol did not cause a pH drop as low as sugars, and were not considered cariogenic, except for allulose potentially causing root caries. Sugar substitutes were not able to prevent a pH drop to near 3.5 after the glucose challenge indicating these substitutes are not anticariogenic in the presence of glucose.

ABSTRACT Treponema denticola is an indigenous oral spirochete that inhabits the gingival sulcus or periodontal pocket. Increased numbers of oral treponemes within this environment are associated with localized periodontal inflammation, and they are also part of an anaerobic polymicrobial consortium responsible for endodontic infections. Previous studies have indicated that T. denticola stimulates the innate immune system through Toll-like receptor 2 (TLR2); however, the pathogen-associated molecular patterns (PAMPs) responsible for T. denticola activation of the innate immune system are currently not well defined. In this study, we investigated the role played by T. denticola periplasmic flagella (PF), unique motility organelles of spirochetes, in stimulating an innate immune response. Wild-type T. denticola stimulated the production of the cytokines tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), IL-6, IL-10, and IL-12 by monocytes from human peripheral blood mononuclear cells, while its isogenic nonmotile mutant lacking PF resulted in significantly diminished cytokine stimulation. In addition, highly purified PF were able to dose dependently stimulate cytokine TNF-α, IL-1β, IL-6, IL-10, and IL-12 production in human monocytes. Wild-type T. denticola and the purified PF triggered activation of NF-κB through TLR2, as determined using a variety of TLR-transfected human embryonic 293 cell lines, while the PF-deficient mutants lacked the ability to stimulate, and the complemented PF-positive T. denticola strain restored the activation. These findings suggest that T. denticola stimulates the innate immune system in a TLR2-dependent fashion and that PF are a key bacterial component involved in this process.

aDepartment of Pediatric Dentistry, School of Dentistry, The University of Alabama at Birmingham, Birmingham, Alabama, USA bDepartment of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, Kentucky, USA cDepartment of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, Kentucky, USA dGene Therapy Program, Allegheny Health Network, Pittsburgh, Pennsylvania, USA eDepartment of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, Michigan, USA

PURPOSE The purpose of this study was to evaluate Streptococcus mutans genotypes (GT) between mother and child (M-C) in a high caries risk cohort to explore the association with early childhood caries (ECC). METHODS Sixty-nine infants (each approximately one year old) had periodic oral examinations (dmfs) and microbial samples collected from dental plaque, saliva, and other oral surfaces. Their mothers had an examination and plaque collected. S mutans isolates were genotyped using repetitive extragenic palindromic-PCR (rep-PCR). Statistical analyses were conducted for associations of S mutans in M-C dyads with caries outcomes. RESULTS Twenty-seven S mutans genotypes (GT) from 3,414 isolates were identified. M-C were categorized as GT match (n equals 40) or no-match (n equals 29). When modeling the severity of ECC at 36 months (approximately four years old), the estimated dmfs in the match group was 2.61 times that of the no-match group (P=.014). CONCLUSIONS Colonization of children with Streptococcus mutans genotypes that matched with mothers was shown to be highly associated with early childhood caries. Although the data suggest vertical transmission of S mutans in 40 of 69 children that shared GT with their mother, it is possible that other individuals transmitted the S mutans. Nonetheless, these findings support the importance of the mother's oral microbial status as a contributing influence to their children's oral health.

The 1980 Oral Science Monograph by L.J. Baume of Geneva is an erudite review, which recognized notables who elevated the respect of histology of dentine & pulp to scientific maturity [1]. Before 1500, “dental surgery” was basically tooth extraction until 1528 when Johannes Stocker recommended treating tooth pain with pulp cautery & filling some canals with copper. Microscopic observation began in 1675 when Anton van Leeuwenhoek (1632-1723) described transparent pipes from pieces of his wife’s tooth using his homemade microscope & compared tooth enamel & cementum to tree bark. In 1824, Edward Hudson (1762-1857) of Philadelphia cauterized the tooth pulp & plugged the canal with gold foil. In 1840, Robert Owen (1804-1892) received recognition by many colleagues for introducing the histologic term DENTINE into our dental lexicon. Histologic knowledge of normal & pathologic tooth tissues rapidly advanced with microscopic technologies of sectioning & staining. In 1879, professor Adolph Witzel’s (1847-1906) histological study described pulp inflammation & neo-dentine formations following vital pulp capping of human teeth treated with arsenious acid—he is recognized as the father of histological endodontics [2]. Grossman’s 1940 textbook advanced ENDODONTICS as a US clinical specialty by promoting DIFFERENTIAL DIAGNOSIS in patients who were suffering from pulpal or periapical pathology, which led to PROGNOSIS & TREATMENT based on a blend of clinical observations with knowledge of pulp histology. Histological advancements of tooth tissue rapidly advanced the knowledge of normal & pathological healing, which fostered ENDODONTICS & RESTORATIVE clinical specialties in the early 1900’s. Dr. Wm. Cotton personally backed the PULP BIOLOGY GROUP as a research specialty during the 1975 London IADR meeting. Endodontic tooth treatment rapidly progressed by using new technologies to assist the diagnosis & treatment of tooth infections. Correspondence to: Charles F. Cox, DMD, PhD, Department of Operative Dentistry, School of Dental Medicine, Tsurumi University, 2-1-3, Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan, Tel: (810)-275-8361; Fax: (810)636-4201, E-mail: cfcox@phoenixdental.com

Ancient humans believed in myths-that tooth pain was due to evil spirits [1].Homer-the Greek author even wrote of tooth pain in his classical epics [2].The European renaissance-circa 1350 to 1600-attributed tooth pain to worms that were allegedly found in tooth lesions [3].Scientific methodology has described 3-theories of dentine sensitivity: (1) In 1770 Hunter suggested tooth sensitivity was due to pulpal nerves [4].(2) In 1842 Neill 1 st proposed that tooth sensitivity was due to fluid movement in the dentine tubules [5].(3) In 1856 J Tomes implicated odontoblast processes (OP's) in the dentine tubules as initiating tooth sensitivity [6].In 1899 Gysi reported that dentine sensitivity was clinically activated by fluid-flow in the dentine tubules [7].In 1968 Brännström proposed the hydrodynamic fluid-flow theory of dentine sensitivity [8].Using LM & TEM Mummary (1916), Tiegs (1938), Bernick (1948), Fearnhead (1961), Itoh (1976) & others observed nerve fibers in the predentine & dentine tubules.Using TEM Arwill (1967) described 8-sub-patterns of nerve fibers in the dentine tubules & Frank (1968atubules & Frank ( , 1972tubules & Frank ( , 1975)).Corpron & Avery (1973) observed nerve fibers extending ≈150µm from the predentine interface into the dentine tubules by TEM.Detailed LM, TEM & SEM studies-by Gunji-reported 4-nerve patterns in the predentine-dentine region.In 1958 Avery & Rapp reported acetylcholine receptors on odontoblasts.Some primate OP's have been shown to extend the length of the dentine tubule [9] & some cross the basement membrane of the enamel-dentine-junction (EDJ) as enamel spindles.All eukaryotic cells display cilia, which are classified as specialized motile or sensory organelles that mediate gradients of sensory perception e.g.pressure, fluid-flow, which perceive environmental stimuli.TEM studies show cilia-extending from odontoblasts into the dentine tubule-suggesting they may be the initial mechano-nociceptor of dentine sensitivity [10].

Generations before sugar was implicated with caries-vitamin-C deficiency (scurvy) had plagued humans for millennia.Early humans treated tooth pain with folkremedies & bloodletting by moonlight-when these cures failed, roadside itinerants with little training promoted extractions.King Philip II established the Parisian Barber-Surgeon Guild in 1210, requiring proper credentials to extract teeth.Edentulous US colonists of the 1800's supported development of MECHANICAL DENTISTRY to fabricate dentures with artificial teeth.Cheap sugar inspired increased consumption, creating a rapid increase in worldwide caries.OPERATIVE DENTISTRY advanced in the Americas with a few clinicians attempting removal of cavity debris, decay, cleansing & restoration with agents to reestablish form & function.Dr. C.A. Harris of Ohio is acknowledged to have actively endorsed dentistry as a clinical profession.Dr. M.H. Webb's 1883 OPERATIVE DENTISTRY textbook commanded international recognition by defining gold-foil cavity preparation & restoration, stressing attention to detail.By 1890, Dr. G.V. Black had outlined scientific guidelines for amalgam composition & defined OPERATIVE cavity resistance & retention form & restoration.By 1839, Drs.Harris & Hayden were recognized to have given OPERATIVE DENTISTRY its parturition at Baltimore Dental College.By 1870, America gained international respect with the founding of 9-accreditated dental schools.US clinicians organized active regional dental societies, developed vulcanite-dentures, scalers, rubber-dam,

BACKGROUND:Dental erosion is the chemical dissolution of tooth structure in the absence of bacteria when the environment is acidic (pH < 4.0). Research indicates that low pH is the primary determinant of a beverage's erosive potential. In addition, citrate chelation of calcium ions may contribute to erosion at higher pH. The authors of this study determined the erosive potential measured by the pH of commercially available beverages in the United States.METHODS:The authors purchased 379 beverages from stores in Birmingham, Alabama, and categorized them (for example, juices, sodas, flavored waters, teas, and energy drinks) and assessed their pH. They used a pH meter to measure the pH of each beverage in triplicate immediately after it was opened at a temperature of 25°C. The authors recorded the pH data as mean (standard deviation).RESULTS:Most (93%, 354 of 379) beverages had a pH of less than 4.0, and 7% (25 of 379) had a pH of 4.0 or more. Relative beverage erosivity zones based on studies of apatite solubility in acid indicated that 39% (149 of 379) of the beverages tested in this study were considered extremely erosive (pH < 3.0), 54% (205 of 379) were considered erosive (pH 3.0 to 3.99), and 7% (25 of 379) were considered minimally erosive (pH ≥ 4.0).CONCLUSIONS:This comprehensive pH assessment of commercially available beverages in the United States found that most are potentially erosive to the dentition.PRACTICAL IMPLICATIONS:This study's findings provide dental clinicians and auxiliaries with information regarding the erosive potential of commercially available beverages. Specific dietary recommendations for the prevention of dental erosion may now be developed based on the patient's history of beverage consumption.

Treponema denticola has been recognized as an important oral pathogen of the "red complex" bacterial consortium that is associated with the pathogenesis of endodontal and periodontal diseases. However, little is known about the virulence of T. denticola due to its recalcitrant genetic system. The difficulty in genetically manipulating oral spirochetes is partially due to the lack of antibiotic resistance cassettes that are useful for gene complementation following allelic replacement mutagenesis. In this study, a kanamycin resistance cassette was identified and developed for the genetic manipulation of T. denticola ATCC 35405. Compared to the widely used ermF-ermAM cassette, the kanamycin cassette used in the transformation experiments gave rise to additional antibiotic-resistant T. denticola colonies. The kanamycin cassette is effective for allelic replacement mutagenesis as demonstrated by inactivation of two open reading frames of T. denticola, TDE1430 and TDE0911. In addition, the cassette is also functional in trans-chromosomal complementation. This was determined by functional rescue of a periplasmic flagellum (PF) deficient mutant that had the flgE gene coding for PF hook protein inactivated. The integration of the full-length flgE gene into the genome of the flgE mutant rescued all of the defects associated with the flgE mutant that included the lack of PF filament and spirochetal motility. Taken together, we demonstrate that the kanamycin resistance gene is a suitable cassette for the genetic manipulation of T. denticola that will facilitate the characterization of virulence factors attributed to this important oral pathogen.

Background. Liquid antimicrobial soaps are commonly used in the dental health care setting for hand washing to minimize the potential spread of infectious agents to health care workers and patients. The purpose of the current study was to evaluate possible bacterial contamination of antimicrobial liquid soap dispensers located in 2 institutional comprehensive dental care clinics.Methods. Fourteen soap dispensers and 16 original stock containers were sampled. A 1-milliliter aliquot was diluted in 10 mL of phosphate buffer (Tween-80; Acros). Serial dilutions were plated in duplicate on neutralizing agar and incubated for 7 days. Molecular identification was performed using 500 base pair comparisons of 16S ribosomal ribonucleic acid sequencing. Taq polymerase chain reaction was performed with sequence-specific primers for Raoultella species.Results. Bacterial growth was observed at 18 hours for 57% (8 of 14) of soap dispenser samples. Bacterial densities ranged from 4 X 102 to 6 X 10(9) colony-forming units per milliliter. Original commercial containers exhibited no growth. Isolates were identified as Raoultella (Klebsiella) planticola.Conclusions. This is the first study to the authors' knowledge indicating recovery of R planticola from antimicrobial liquid soap dispensers. R planticola is a recognized environmental opportunistic pathogen that potentially poses a health concern.Practical Implications. These findings indicate compliance problems with infection prevention recommendations and support the US Centers for Disease Control and Prevention's recommendation that dispensers should not be topped off. High bacterial loads of R planticola are inconsistent with infection control practices and are a concern because transmission and possible infection to the health care worker or the patient may occur.

The primary etiological agents associated with dental caries include the mutans streptococci (MS) comprised of Streptococcus mutans and Streptococcus sobrinus. The effective cultivation and isolation of MS are necessary for the study of MS, including their proper clinical assessment in the epidemiological study of dental caries. Several selective media have been developed for the isolation, enumeration, and characterization of MS. However, inhibition of MS may occur, reducing counts and perhaps limiting selection of some strains. The purpose of this study was to compare five culture media containing bacitracin recommended for the isolation of MS. Five commonly used bacitracin-containing media (MSB, MSKB, GTSB, TYS20B, and TYCSB) used for MS isolation were quantitatively evaluated. Standard plate counts were performed in duplicate for 2 prototype MS strains (S. mutans UA159 and S. sobrinus 6715) and for MS isolates from clinical saliva samples obtained from 16 children (approximate age 5years) to determine total plate counts, and total S. mutans counts. Selected isolates (n=249) from all five media for 5 saliva samples were further confirmed as S. mutans with real-time PCR then subsequently evaluated qualitatively with rep-PCR for genotype determination. All media resulted in variable enumeration with no significant difference in MS counts. MS prototype strains grew well on all five media; clinical isolates demonstrated more variability in counts but no overall significant differences were found. MSB demonstrated comparable ability to grow S. mutans but allowed for more non-S. mutans growth. All 5 media identified a consistent predominant genotype by rep-PCR. Recovery of minor genotypes was not inhibited by media type.

BACKGROUND:Tissue breakdown in periodontitis is initiated by bacteria, such as Porphyromonas gingivalis, and is caused largely by host responses. Resolvins protect the host against acute inflammation by blocking the migration of polymorphonuclear neutrophils to initiate resolution. The effects of resolvins on human gingival fibroblasts (HGFs) are unknown. This study examines the effects of resolvin D1 on HGF survival and cytokine expression when treated with or without P. gingivalis supernatant.METHODS:Cytotoxicity of resolvin D1 on HGFs with or without a toxic level of P. gingivalis supernatant was measured with lactate dehydrogenase assays. Cytokine arrays were performed on HGF-conditioned media treated with or without resolvin D1 and with or without P. gingivalis supernatant.RESULTS:Resolvin D1 had no cytotoxic effects on HGFs at concentrations between 1 and 1,000 nM (all P > 0.05). Resolvin D1 (1,000 nM) significantly inhibited the toxic effects of 13.5% (v/v) P. gingivalis supernatant on HGFs (P = 0.002). Resolvin D1 significantly reduced the expression of interleukin (IL)-6 (P = 0.010) and monocyte chemoattractant protein (MCP)-1 (P = 0.04) in untreated fibroblasts. P. gingivalis (10%) supernatant significantly increased the expression levels of granulocyte-macrophage colony-stimulating factor (CSF), granulocyte CSF, growth-regulated oncogene (GRO), IL-5, IL-6, IL-7, IL-8, IL-10, MCP-1, MCP-2, MCP-3, and monokine induced by γ-interferon. Resolvin D1 significantly reduced the expression of GRO (P = 0.04), marginally reduced the levels of MCP-1 (P = 0.10), and marginally increased the levels of transforming growth factor (TGF)-β1 (P = 0.07) from HGFs treated with P. gingivalis supernatant.CONCLUSIONS:Resolvin D1 altered the cytotoxicity of P. gingivalis supernatant on HGFs. Resolvin D1 significantly reduced GRO, marginally reduced MCP-1, and marginally increased TGF-β1 from P. gingivalis-treated HGFs, which could alter the ability of P. gingivalis to induce inflammation.

This longitudinal cohort study evaluated the diversity, commonality, and stability of Streptococcus mutans genotypes associated with dental caries history. Sixty-seven 5- and 6-yr-old children, considered as being at high caries risk, had plaque collected from baseline through 36 months for S. mutans isolation and genotyping using repetitive extragenic palindromic-PCR (4,392 total isolates). Decayed, missing, or filled surfaces (dmfs (primary teeth)/DMFS (secondary teeth)) for each child were recorded at baseline. At baseline, 18 distinct genotypes were found among 911 S. mutans isolates from 67 children (diversity), and 13 genotypes were shared by at least two children (commonality). The number of genotypes per individual was positively associated with the proportion of decayed surfaces (p-ds) at baseline. Twenty-four of the 39 children who were available at follow-up visits maintained a predominant genotype for the follow-up periods (stability) and this was negatively associated with the p-ds. The observed diversity, commonality, and stability of S. mutans genotypes represent a pattern of dental caries epidemiology in this high-caries-risk community, which suggests that fewer decayed surfaces are significantly associated with lower diversity and higher stability of S. mutans genotypes.

In-office dental unit waterline (DUWL) testing systems are commercially available for monitoring DUWL bacteria. The current study compared Aquasafe, Petrifilm, and Heterotrophic Plate Count Sampler (HPCS) with R2A plating methodology, considered the gold standard for enumerating heterotrophic bacteria in potable water. Samples were collected from 20 dental units. Heterotrophic bacterial counts of ≤500 CFUs/mL were used as the cut-off for assessing in-office testing compared to R2A laboratory plating. Validity was assessed using sensitivity and specificity, along with positive and negative predictive values. Results were also compared using concordance and kappa statistics. All in-office tests demonstrated 100% specificity and positive predictive values, while sensitivity and negative predictive values were low (Petrifilm, 57%/50%; HPCS, 50%/46%; Aquasafe, 21%/35%). Concordance and kappa values for agreement with R2A plating were as follows: Petrifilm 70% (κ = 0.44), HPCS 65% (κ = 0.38), and Aquasafe 45% (κ = 0.14). In-office DUWL testing with Aquasafe, Petrifilm, and HPCS agreed poorly with R2A plating methodology and is not valid or reliable as a means of accurately monitoring bacterial density in DUWL. These in-office test systems should not be used for assessing compliance with the ADA and CDC standard for acceptable heterotrophic bacterial counts in DUWLs (≤500 CFUs/mL).

BACKGROUND:Alternatives to vital pulpotomy treatment in primary teeth are being sought because of the high formaldehyde content of traditional formocresol (FC) pulpotomy medicaments.AIM:The aim was to compare the clinical and radiographic success of vital pulpotomy treatment in primary molars using 3% sodium hypochlorite (NaOCl) versus a 1:5 dilution of Buckley's FC.DESIGN:Pulpotomies were performed in primary molars of healthy children between 3 and 10 years old. Sixty-five primary teeth were randomized into two groups that were evaluated for treatment outcomes. Following treatment, the pulp chamber was filled with zinc oxide eugenol (ZnOE) and restored with a stainless steel crown cemented with glass ionomer cement. Clinical and radiographic outcomes were recorded at 6 and 12 months.RESULTS:The control (FC) and experimental (NaOCl) groups demonstrated 100% clinical success at 6 and 12 months. The NaOCl group had 86% (19/22) radiographic success at 6 months and 80% (12/15) at 12 months. The FC group had 84% (21/25) radiographic success at 6 months and 90% (9/10) at 12 months. No significant differences were found in the radiographic outcomes between the two groups at 6 and 12 months (Fisher's exact test; P=0.574 and P=0.468, respectively).CONCLUSION:NaOCl demonstrated clinical and radiographic success comparable to FC.

BACKGROUND:Tobacco smoking is considered a major modifiable risk factor for periodontal disease. Nicotine is the addictive ingredient in tobacco and has been shown to affect multiple cellular processes. Neutrophils are the first line of host defense and are critical cells in the maintenance of periodontal health through their role in the control of bacteria, but they can also contribute to the progression of periodontal disease by the production and release of reactive oxygen species (ROS). Virulence factors from periodontal pathogens, such as Porphyromonas gingivalis (Pg), stimulate the respiratory burst of neutrophils. The objective of this study is to explore the oxidative activity of neutrophils when stimulated with Pg, nicotine, or both.METHODS:Neutrophils were separated from buffy coats by the double dextran gradient method. The generation of ROS by neutrophils was determined using luminol-dependent chemiluminescence assays. The reaction was followed for 90 minutes, and the neutrophil activation was recorded as the total integrated energy output.RESULTS:The Pg and Pg plus nicotine groups had a significantly higher active and peak chemiluminescence than the nicotine group (all with P <0.0001). The Pg and Pg with nicotine groups were not significantly different (P = 0.90).CONCLUSION:In the presence of Pg, the nicotine did not further enhance the ROS release by the neutrophils, suggesting that the bacteria induced the maximum ROS release in this model system.

This study compared SYBR Green real-time quantitative PCR (qPCR) with standard plate counting for the enumeration of Streptococcus mutans in oral samples. Oral samples (n = 710) were collected from high-caries-risk children for quantification of S. mutans by qPCR using primer pairs. The S. mutans copy number was calculated with reference to a qPCR quantification cycle (Cq) standard curve and compared with the absorbance value at 600 nm of a standard suspension of S. mutans UA159. The S. mutans copy number results were evaluated in relation to standard plate count (SPC) results obtained from each sample following culture on Petri plates containing S. mutans selective media and reported as colony-forming units (CFUs). The mean S. mutans copy number calculated from qPCR was higher than the SPC CFUs (1.3 × 10(6) and 1.5 × 10(5) CFUs, respectively). The qPCR values were usually higher in individual samples and qPCR detected the presence of S. mutans 84% (231/276) of the time that the SPC did not, compared with 33% (4/12) of the time when qPCR failed to detect S. mutans and the SPC did. The qPCR technique was found to be more sensitive for detection of S. mutans from oral samples, a method that is not dependent on the viability of the sample taken and therefore is proposed as a more reliable and efficient means of quantification of S. mutans.

This historical treatise follows the documented timeline of tooth decay into today's understanding, treatment, and teaching of caries biology. Caries has been attributed to many different causes for several millennia, however, only since the late 1900s has research revealed its complex multifactorial nature. European writers of the 1600s to 1700s held views that general health, mechanical injuries, trauma, and sudden temperature changes all caused caries—holding a common belief that decay was due to chemical agents, faulty saliva, and food particles. Until the early 1800s most writers believed that caries was due to inflammation from surrounding diseased alveolar bone. Today's science has demonstrated that caries is caused by indigenous oral microorganisms becoming a dynamic biofilm, that in the presence of fermentable sugars produce organic acids capable of dissolving inorganic enamel and dentin followed by the proteolytic destruction of collagen leaving soft infected dentin. As bacteria enter the pulp, infection follows.