Genome-wide association scan for childhood caries implicates novel genes

Dental caries is the most common chronic disease in children and a major public health concern due to its increasing incidence, serious health and social co-morbidities, and socio-demographic disparities in disease burden. We performed the first genome-wide association scan for dental caries to identify associated genetic loci and nominate candidate genes affecting tooth decay in 1305 US children ages 3-12 yrs. Affection status was defined as 1 or more primary teeth with evidence of decay based on intra-oral examination. No associations met strict criteria for genome-wide significance (p < 10E-7); however, several loci (ACTN2, MTR, and EDARADD, MPPED2, and LPO) with plausible biological roles in dental caries exhibited suggestive evidence for association. Analyses stratified by home fluoride level yielded additional suggestive loci, including TFIP11 in the low-fluoride group, and EPHA7 and ZMPSTE24 in the sufficient-fluoride group. Suggestive loci were tested but not significantly replicated in an independent sample (N = 1695, ages 2-7 yrs) after adjustment for multiple comparisons. This study reinforces the complexity of dental caries, suggesting that numerous loci, mostly having small effects, are involved in cariogenesis. Verification/replication of suggestive loci may highlight biological mechanisms and/or pathways leading to a fuller understanding of the genetic risks for dental caries.     

Subjective patients' opinion and evaluation of halitosis using halimeter and organoleptic scores

Objectives:  The aim of the study was to evaluate the level of interest in fetor ex ore among respondents, patients of the Department of Conservative Dentistry in Warsaw.
Materials and Methods:  A questionnaire was completed by 295 patients, 202 females and 93 males aged 18–74 years (average 38.73 years). Each person was also examined for organoleptic score and volatile sulfur compounds (VSC) by Halimeter. Halitosis was diagnosed if the average level of VSC was ≥125 ppb and the organoleptic measurement using a 0–5 point scale was ≥2. Statistical analysis was performed using chi-square test.
Results:  Incidence of halitosis was greatest in age ranges 25–34 years (29.68%) and 45–54 years (24.52%). Sixty-eight (43.87%) persons with diagnosed halitosis frequently reported having a problem with bad breath and only 5.81% persons with halitosis did not notice this problem ( P  < 0.001). Among 54 healthy persons three (5.56%) reported having a problem with halitosis ( P  < 0.001).
Conclusion:  A statistically significant correlation was found between clinical organoleptic diagnosis of halitosis and VSC level by halimeter. Subjective patients' opinion correlated well with objective evaluation of halitosis.     

The measurement in vitro of enamel and dentine wear by toothpastes of different abrasivity

Objectives : To investigate the in vitro enamel and dentine wear by toothpastes with a range of Relative Dentine Abrasivity (RDA) and Relative Enamel Abrasivity (REA) values. Methods : Human enamel/dentine (approximately 50:50) blocks (approximately 4 × 4 mm) were polished and the enamel indented with four Knoop indents. The step across the enamel‐dentine junction was measured by interference microscopy. Specimens were brushed in vitro with toothpastes with a range of RDA/REA values using a flat trim toothbrush mounted in a Wira brushing machine for 360s and a load of 375g. After brushing the Knoop indent length and the enamel‐dentine step were remeasured and the amount of wear to the enamel and dentine was calculated. Results : The mean enamel wear ranged from 0.05 to 0.40 microns, with the highest wear for the highest REA product. The mean dentine wear for all toothpaste products tested was positively correlated with RDA value (R² = 0.897). The correlation was further improved if median wear values were used (R² = 0.930). Conclusions : This study has demonstrated a rapid technique for the simultaneous investigation of the abrasive wear of toothpaste on enamel and dentine. There was a good correlation between median dentine wear and RDA values.     

Abrasion of human enamel and dentine caused by toothpastes of differing abrasivity determined using an in situ wear model

Objectives : To determine the rates of enamel and dentine wear in situ during tooth brushing with a range of five toothpastes of differing RDA and REA values. Methods : Enamel/dentine inserts were placed in the buccal aspects of full upper dentures of human volunteers. Enamel wear was determined by change in Knoop indent length and dentine wear was determined from the enamel‐dentine step height, measured using optical profilometry. Results : Significant differences between the test products were found for both enamel and dentine (p < 0.05). However for the conventional toothpastes the rate of wear was similar and differences between the products were not generally statistically significant for either enamel or dentine, despite the fact that their RDA values differed by more than a factor of two. The rate of wear was found to decrease throughout the duration of the study. Conclusions : The study demonstrated that the methodology used is capable of assessing enamel and dentine wear in situ within a relatively short period of time. The data suggest that whilst in vitro tests have value in understanding differences in abrasivity between products, they cannot be used to predict in vivo effects.     

Regulatory aspects of N-linked glycoproteins

Activation of beta-adrenoreceptors in rat parotid acinar cells leads to copious exocrine protein secretion. Additionally, beta-adrenergic stimulation dramatically increases specific secretory protein synthesis and enhances N-linked glycosylation of secretory glycoproteins. Recently, efforts have been directed toward understanding the mechanisms underlying these biosynthetic events. We have been particularly interested in the receptor-mediated regulation of glycosylation. In this report, we evaluate available mechanistic information from the rat parotid gland and present initial data examining the ability of various regulatory agents to modulate N-linked glycosylation in enzymatically-dispersed cell aggregates from surgical specimens of human parotid glands. We conclude that glycosylation of human parotid N-linked glycoproteins may be regulated by extracellular signaling similar to that operative in the rat parotid gland.     

Pattern of distribution of T lymphocytes, Langerhans cells and HLA-DR bearing cells in normal human oral mucosa

The tissue distribution of helper/inducer and suppressor/cytotoxic T cells, Langerhans cells (LC) and HLA-DR bearing cells was determined in normal oral mucosa by use of monoclonal antibodies OKT4, OKT8, OKT6 and OKIa1, respectively. OKT4+ and OKT8+ cells were invariably present in normal oral epithelium and in the lamina propria. OKT8+ cells were consistently seen inside the basal cell layer of the epithelium. The distribution of LC in oral epithelium showed regional variation. In palatal epithelium LC were evenly distributed in the basal half of the epithelium, whereas in buccal mucosa the highest concentration of LC was seen in the epithelium overlying the tips of connective tissue papillae. OKIa1 stained dendritic cells in the epithelium and plump cells with small dendritic processes in the connective tissue. Some of the latter were located close to the basal cells of the epithelium. The consistent relationship between immunocompetent cells and the epithelium of the oral mucosa suggests the presence of a local immunologic defence barrier in the oral mucosa.     

Radiographic detection of porosities in removable partial denture castings

The purpose of this study was to discern the existence of structural defects in removable partial denture frameworks by means of radiographs. A simple technique was described using a dental radiograph unit and routine periapical dental films. All components of removable partial denture castings were radiographed with different angulations. The visibility of defects was clear. Structural defects were located and classified in two brands of removable partial denture base metal alloys (Ticonium and Nobilium) commonly used in fabrication of removable partial denture castings. The technique described is simple, inexpensive, not time-consuming, and can be implemented with minimum instrumentation. Future studies with this radiographic method for investigation of internal defects in fixed prostheses or dental implants are recommended.     

Shrink-free ceramic

An all-ceramic crown employing the Cerestore system utilizes a unique shrink-free alumina ceramic as its substrate. This core renders the restoration exceptional fit and strength. A ceramic layering technique employed with the aluminous porcelain veneers offers the capability of constructing a full crown restoration incorporating the optical properties present in a natural tooth.