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.     

Cleidocranial dysplasia. Case report

A 29-year-old Caucasian woman who presented with short stature and multiple unerupted supernumerary teeth is described. Radiological investigations of her cranial and skeletal abnormalities revealed cleidocranial dysplasia. Because of the advanced age of the patient and contraindication for orthodontic treatment, only surgical and prosthetic treatment were performed. The characteristics and treatments of this rare autosomal dominant disorder are discussed.     

Correlating carotid artery stenosis detected by panoramic radiography with clinically relevant carotid artery stenosis determined by duplex ultrasound

OBJECTIVE: We sought to assess the utility of panoramic radiography as an adjunct screening tool for detecting significant asymptomatic carotid artery stenosis. The specific aim was to correlate calcifications seen in the region of the carotid bifurcation with clinically relevant carotid artery stenosis as determined by duplex ultrasound (DUS). STUDY DESIGN: Routine dental panoramic films of patients 55 and older (n = 778) at the University of Rochester Eastman Dental Center were retrospectively reviewed for calcifications around the carotid bifurcation. Patients with such calcifications were referred for DUS, and raw data were interpreted by a vascular surgeon blinded to the radiographic findings. Groups were compared by using the chi(2) test. RESULTS: Twenty-seven patients (3.5%) had suggestive radiographic calcifications on one or both sides, 20 of whom consented to DUS. Clinically significant carotid stenoses (>50% lumenal narrowing) were present in 50% of the sides with calcification compared with 21% of the sides without (P =.08, chi(2)). Three patients (15% of those screened with DUS) had stenoses greater than 80% and underwent 4 carotid endarterectomies as a direct result of screening. CONCLUSIONS: Data suggest that clinically significant stenosis may exist if calcifications are observed on panoramic radiographs. Incidental examination of this area carries a minimal cost and appears beneficial as a screening tool for carotid disease, although definitive testing must follow.     

Conventional radiographic and computed tomographic findings in cases of fracture of the mandibular condylar process

A total of 40 patients with 46 fractures of the mandibular condylar process were examined an average of 47 months after the injury. The conventional radiologic examination consisted of panoramic radiography and lateral transcranial view of the fracture in the mouth-open and mouth-closed positions. Sixteen patients with 21 fractures of the condylar process were examined additionally by computed tomography (CT) because of temporomandibular joint problems in the sagittal and coronal projection. Computed tomography revealed bony changes in the fractured mandibular condyle and its position in the mandibular fossa more exactly than conventional radiographic examinations. Furthermore, the results showed that disturbances in the position and function of the articular disc may be more common than was earlier anticipated, suggesting the more frequent use of CT examinations to evaluate temporomandibular joint changes after condylar process fractures.     

Correlation between fracture properties and clinical performance of composite resins in Class IV cavities

One hundred and two Class IV cavities were restored randomly with four composite resins. The restorations were assessed at six months, one year, two years and three years for surface chipping, bulk fracture and incisal wear. The data were correlated with various mechanical properties of the materials. A significant correlation was found between surface chipping/bulk fracture and fracture toughness (P = 0.002), elastic modulus (P = 0.006) and tensile strength (P = 0.045). There was a trend towards an association between incisal wear and both elastic modulus and inherent flaw size. Fracture toughness may be a useful indicator of the clinical performance of composites in Class IV cavities.     

Prevalence of Nontraditional Dental Hygiene Practice

There is little knowledge of the number or the work characteristics of dental hygienists outside the private-practice setting. This survey was conducted to determine the percentage of hygienists practicing in nontraditional (nonprivate-practice) settings and the types of settings in which they are employed. Mail questionnaires were returned from a total of 21,847 (56.9%) of the hygienists in the survey sample. The percentage of active hygienists practicing in nontraditional settings was 11.8. Dental or dental hygiene schools, and government and nongovernment-supported clinics were the most frequent nontraditional practice settings. State supervision requirements were found to be associated significantly with the prevalence of nontraditional hygiene practice.     

Effects of preservation on the osteoinductive capacity of demineralized bone powder allografts

Demineralized bone powder (DBP) has repeatedly been shown to serve as an osteoinductive material. The aim of this study was to investigate the effects of different methods of storage of DBP on its osteoinductive property. Forty-five Long Evan rats were used in this study. Twenty rats were used as donors; the diaphyses of their femoral bones were used for the preparation of DBP. The DBP was divided into four portions that were either lyophilized or frozen at -70 degrees C, -4 degrees C, or kept at room temperature (25 degrees C). All samples were stored under the specified condition for six months. At the time of implantation, fresh DBP was prepared and used as a control. Twenty-five rats were divided equally into five groups. Each group received an implant of either one of the differently preserved and stored samples of DBP or fresh DBP. The animals were killed 60 days following implantation. The implants were excised and processed to obtain 5 micron thick decalcified sections and 3 micron thick undecalcified sections. Semicomputerized histomorphometry was used for the quantification of the newly-formed bone in each implant. Newly-formed bone was detected in all experimental and control groups and there were no statistically significant differences between the various groups. It was concluded that DBP retains its osteoinductivity after lyophilization or preservation at -70 degrees C, -4 degrees C, and 25 degrees C for a period of up to six months, and that the different methods of preservation did not significantly affect the amount of the induced newly-formed bone.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of opacifiers on color stability of pigmented maxillofacial silicone A-2186 subjected to artificial aging

PURPOSE: This study was designed to determine the effect of opacifiers used at different ratios on the color stability of pigmented A-2186 silicone maxillofacial elastomers and to evaluate the color spectrophotometrically before and after artificial aging. MATERIALS AND METHODS: Sixty experimental groups of elastomers were made using various concentrations (5%, 10%, and 15%) of 4 opacifiers (Georgia kaolin powder neutral, kaolin powder calcined, Artskin white, and dry pigment titanium white) with 1 of 5 dry earth cosmetic pigment groups (no pigment [control], red, yellow ochre, burnt sienna, and a mixture of all pigments). Five specimens of each elastomer were tested, for a total of 300 specimens. All specimens were placed in an aging chamber and artificially aged by exposure to light, water spray, fluctuating temperatures, and humidity. CIE L*a*b* values were measured by spectrophotometer. The color differences (Delta E*) at various exposure energies (150, 300, and 450 kJ/m(2)) were subjected to 4-way analysis of variance with repeated measures (super ANOVA). Mean values were compared with Tukey-Kramer intervals calculated at the 0.05 significance level. RESULTS: The trained human eye can detect color changes (Delta E*) greater than 1.0. Adding all pigments to any of the kaolin groups did not protect silicone A-2186 from color degradation over time. Mixing red pigment in all groups at all times drastically increased DeltaE* values ranging from 0.1 to 1.3 up to 16.6 to 49.6. Yellow ochre had an effect only with 10% and 15% concentrations of kaolin powder calcined, increasing the value of Delta E* to greater than 1.0. Burnt sienna had an effect only with a 15% concentration of kaolin powder calcined, increasing the value of Delta E* at 300 and 450 kJ/m(2) to greater than 11.0. At the 5% concentration, kaolin powder calcined had the smallest color changes, followed by, in order, dry pigment titanium white, Artskin white, and Georgia kaolin. At the 10% concentration, Artskin white had the smallest color changes, followed by, in order, dry pigment titanium white, kaolin powder calcined, and Georgia kaolin. At the 15% concentration, Artskin white again had the smallest color changes, followed by, in order, dry pigment titanium white, Georgia kaolin, and the kaolin powder calcined. The smallest color changes in each kaolin group were at the 10% concentration for Artskin white, dry pigment titanium white, and kaolin powder calcined and at the 5% concentration for Georgia kaolin. CONCLUSIONS: Mixing dry earth cosmetic pigments with opacifiers did not protect silicone A-2186 from color degradation over time, especially in the case of red pigment. The group in which pigments were mixed with 10% Artskin white had the smallest color changes over time, followed by, in order, the groups in which pigments were mixed with 10% dry pigment titanium white, 10% kaolin powder calcined, and 5% Georgia kaolin. Red pigment had a significant effect on all opacifiers, especially Georgia kaolin and kaolin powder calcined. Yellow ochre and burnt sienna had an effect only on 15% kaolin powder calcined. Among all the pigment groups tested, yellow ochre remained the most color stable over time.     

Application of neural networks to the prediction of lymph node metastasis in oral cancer

Neural networks are a new type of computing algorithm. They are especially useful in pattern recognition. In this study we applied neural networks to the prediction of lymph node metastasis of patients with oral cancer. A data set of 1,116 lymph nodes verified histopathologically was used to train and evaluate the neural networks. Various three-layer feed-forward networks with a back-propagation algorithm were employed in this study. Performance of the neural networks was compared with that of radiologists and discriminant analysis (Quantification theory type II). Neural networks had a sensitivity of 80.6% and a specificity of 94.6%. Diagnostic accuracy of the neural networks was 93.6%, which was comparable to those of discriminant analysis and clinical radiologists.