Relative levels of mRNA encoding enamel proteins in enamel organ epithelia and odontoblasts

Amelogenin, enamelin, sheathlin (ameloblastin/ amelin), enamelysin (MMP-20), and KLK4 (EMSP-1) are the major structural proteins and proteinases in developing tooth enamel. Recently, odontoblasts were reported to express amelogenin, the most abundant enamel protein. In this study, we hypothesized that odontoblasts express all enamel proteins and proteases, and we measured their relative mRNA levels in enamel organ epithelia and odontoblasts associated with porcine secretory- and maturation-stage enamel by RT-PCR, using a LightCycler instrument. The results showed that amelogenin mRNA in secretory-stage EOE is 320-fold higher than in odontoblasts beneath secretory-stage enamel, and over 20,000-fold higher than in odontoblasts under maturation-stage enamel. Similar results were obtained for enamelin and sheathlin. Enamelysin mRNA levels were equivalent in these two tissues, while KLK4 mRNA was higher in odontoblasts than in secretory-stage EOE. These results support the conclusion that odontoblasts are involved in the formation of the enamel layer adjacent to enamel-dentin junction.     

Dental infections and serum inflammatory markers in patients with and without severe heart disease

OBJECTIVE: The objective of this study was to investigate if patients with severe heart disease (CHD patients) present more signs of dental infections than patients without heart disease (non-CHD patients), if serum inflammatory markers differ between the groups, and if there is a link between these and the oral health parameters. METHODS: We performed clinical and radiologic dental examinations and collected serum samples of 256 patients with New York Heart Association class II-IV heart disease (CHD patients) and 250 non-CHD controls. Serum samples were analysed using pertinent methods in the clinical laboratory of the hospital, and the differences in serum biomarkers between CHD patients and non-CHD patients were examined using various statistical methods. A modified dental index (MDI) was constructed and used in the analyses. RESULTS: CHD patients were significantly more likely to be edentulous (34.8% vs. 14.8%) and retain less natural teeth than non-CHD patients (8.6 vs. 17) (P <.001). In CHD patients the remaining teeth and supporting tissues were more often diseased. High MDI scores were significantly associated with CHD status (OR 1.31, CI 1.16-1.48), as was gingivitis (OR 3.37, CI 1.66-6.86), while the presence of deep periodontal pockets was not. Serum C-reactive protein and fibrinogen concentrations and blood erythrocyte sedimentation rates were higher in the CHD group. Also, H. pylori and Chlamydia antibodies were significantly higher in the CHD group. CONCLUSION: CHD patients presented with poorer oral health status than non-CHD patients. Serum inflammatory markers were significantly higher in the CHD patients compared to the non-CHD group. High MDI scores linked with risk of CHD.     

Pain experienced by patients during periodontal maintenance

BACKGROUND: The aims of this study were to determine: 1) the degree of pain experienced by patients during probing and debridement; 2) whether the treating hygienists could estimate the degree of pain experienced by the patients; and 3) whether the patients' pain responses could be predicted by factors such as the patients' age, gender, number of residual periodontal lesions, and answers to a questionnaire on dental anxiety. METHODS: Prior to periodontal maintenance procedures, two groups of 20 adult patients to be treated by two hygienists completed an anxiety questionnaire. Subsequently, measurements of probing depths were performed, followed by pain ratings by each patient using a visual analog scale (VAS). The hygienists also completed a VAS, estimating the pain level they perceived their patient to have experienced. The same protocol was repeated for instrumentation (debridement). RESULTS: Most patients showed low pain responses to both probing and instrumentation. However, using an arbitrary threshold of VAS > or = 40 mm, 20% to 33% of the patients had a significant pain experience. The hygienists were quite accurate in their relative estimates of their patients' pain experiences. Regression analyses disclosed that significant portions of the pain responses could be predicted by the patients' answers to one of the dental anxiety questions. CONCLUSIONS: Recognition of patients who are likely to experience significant pain during periodontal treatment may be facilitated by the use of one question on dental anxiety. During treatment, the ability to gauge and respond to patients' pain experiences would seem to be an important component of a therapist's clinical skills.     

Decontamination of tried-in orthodontic molar bands

Molar bands are commonly used to retain orthodontic attachments on posterior teeth and due to the variation in the size of such teeth, it is usually necessary to 'try in' several bands before the correct one is selected. A possible concern with re-using such bands is the lack of cross-infection control, even following autoclaving, due to the presence of one or more small bore lumen (the archwire and headgear tubes). The aim of this experiment was, therefore, to determine whether such bands could be successfully decontaminated so that they could be re-used without a cross-infection risk. Two hundred orthodontic molar bands that had previously been tried in patients' mouths, but not cemented into place, were tested. Each band was decontaminated using an enzymatic cleaner/disinfectant and then sterilized using either a downward displacement (n = 100) or a vacuum cycle autoclave (n = 100). Following autoclaving each band was inoculated into brain heart infusion culture broth and incubated at 37 degrees C for 5 days. None of the decontaminated bands exhibited growth after 5 days. It would appear that, using this methodology, there is little risk of a cross-infection hazard occurring with the re-use of previously tried-in and decontaminated molar bands.     

Serum mepivacaine concentrations after intraoral injection in young children

The authors measured plasma concentrations of mepivacaine in 36 children from the ages of 2 to 5 years who received dental care under light general anesthesia. The subjects were randomly assigned to receive either 2 percent mepivacaine hydrochloride with 1:20,000 levonordefrin or 3 percent mepivacaine hydrochloride without vasoconstrictor. The volume of anesthetic injected depended on the planned procedures for each patient. Blood samples (3 mL) were drawn from an intravenous line before and 5, 10, 20, 30, 45, and 60 minutes after mepivacaine injection. The serum was collected and analyzed by gas-liquid chromatography. Mean serum concentrations, normalized to a dose of 1 mg/kg body weight, reached a peak of 0.67 +/- 0.42 microgram/mL (mean +/- SD) after 3 percent mepivacaine and 0.63 +/- 0.21 microgram/mL after 2 percent mepivacaine with levonordefrin. Levonordefrin had no significant effect on the plasma concentrations. However, because of the higher concentration of mepivacaine in the 3 percent formulation, it was potentially 1.5 times as toxic (P < 0.002) on a volume basis. Statistical analysis also suggested that the maximum recommended dose of 3 mg/lb could result in potentially toxic blood concentrations in a small percentage of pediatric patients. The authors conclude that 3 percent mepivacaine should not be used when relatively large volumes of local anesthetic must be administered to small children and recommend that the maximum dose of mepivacaine not exceed 5 mg/kg.     

Prevalence of impacted permanent upper canine and its treatment in 11-18-year-old orthodontic patients

Data of literature show very high prevalence of impacted upper permanent canine. The aim of the present study was to evaluate prevalence of retentioned or impacted upper permanent canines and to present their therapy. Data on 11-18-year-old children presented for treatment at the Department of Dentistry for Children and Orthodontics in Budapest over a period of 10 years (between 1990 and 2000) were analysed. OP X-ray films of 1858 children and adolescents--1102 female and 756 male--were examined and the data of anamnesis and the administered therapy were considered. Results revealed 101 cases of impacted cuspids, the male:female ratio was 46:55. Considering the totality of administered treatment methods, both surgical exposure and orthodontic treatment of the affected canines were needed in a high rate, i.e. 96.92% of the analysed cases. In 40.91% of the cases extraction of the correspondent upper first premolar was needed. Following the premolar extraction spontaneous occlusions of the impacted canine was established in 3.03%. Authors present the complex therapy of one case of palatally impacted upper permanent canine.     

Effect of bismuth subgallate (local hemostatic agent) on wound healing in rats. Histological and histometric findings

The aim of this research was to evaluate the effect of bismuth subgallate on wound healing. In 40 Wistar rats, two standard wounds (3.5 mm x 2 mm) were made using a biopsy punch on the back of each animal. Test wounds were filled with bismuth subgallate and control wounds with 0.9% saline. At 1, 4, 7, 11 and 18 days, the qualitative evolution of the granulation tissue morphology was observed and digitalized histologic images were evaluated. There were no significant histological differences between test and control. Histometrically, there were statistically significant differences between test and control (ANOVA--days 1 and 4; Student t test, p < 0.05--days 7, 11 and 18) in terms of the following parameters: area of ulceration--day 1; distance between epithelial edges--day 4; area of granulation tissue--days 7, 11 and 18. It was concluded that bismuth subgallate is biocompatible to the healing tissue, and did not interfere with the normal development of wound healing.     

Bacterial and yeast flora of root surface caries in elderly,ethnic Chinese

OBJECTIVES: Root caries is emerging as a significant problem in the middle aged and elderly. As little data is available on the microbiology of root caries in Chinese cohorts, we evaluated 30 such lesions in elderly, institutionalized, ethnic Chinese. METHODS: Samples of carious dentine were aseptically taken from root caries lesions of 18 subjects (five males and 13 females, mean age 79.67 +/- 8.57). The cultivable bacteria, both aerobic and anaerobic, were isolated and identified using standard methods and commercial identification kits. The yeasts were isolated on Sabouraud's agar and identified using the API system. RESULTS: The main findings were: (1) of the total isolates, 91.09% were Gram-positive and 8.91% were Gram-negative microorganisms; (2) the proportions of cocci and rods were 36.68 and 63.31%, respectively; (3) the predominant groups of organisms isolated were Streptococcus spp., Lactobacillus spp., Staphylococcus spp. and Actinomyces spp. with isolation frequencies of 100, 90.00, 73.33 and 63.33%, respectively; (4) the isolation frequency of yeasts belonging to Candida spp. (63.33%) was notably high although the proportion of yeasts within each sample was low (0.01%). Candida dubliniensis, a newly identified yeast species particularly prevalent in HIV infection, comprised 14.29% of yeasts. CONCLUSIONS: This study provides baseline information on the microbiologic features of root caries in the elderly, ethnic Chinese. Whilst our data on the most predominant bacteria isolated in root caries concur with those from other regions of the world the isolation of C. dubliniensis from these lesions has not been documented before.