Specifications for the occlusal aspects of dental restorations.

A mandibular overdenture technique has been presented that utilizes the Dolder bar joint attachment. Endodontically treated lower canines were retained as abutments.Two techniques for attaching the bar to teeth with divergent root canals were discussed: (1) the Schubiger screw system for those teeth with extremely divergent canals and (2) the Stutz pivots system for teeth with only slightly divergent root canals.The use of the Dolder bar joint offers periodontally involved teeth an improved crown/root ratio and splinting of the teeth. Because the bar is close to the alveolar bone, forces of mastication exert much less leverage to the teeth. Finally, the bar joint offers slight vertical and rotational movement of the denture as well as a stressbreaker action.     

Fluoride in human saliva after ingestion of aluminium chloride and sodium fluoride or sodium monofluorophosphate

Four fasting adults were given 5 mg of F as NaF or Na₂PO₃F without and with 3.5, 7.1 or 14.2 mg Al as AlCl₃. Each salt combination was administered in 1 ml aqueous solution, and swallowed in a gelatine capsule with 10 ml of water. Samples of paraffin-stimulated whole saliva, collected before and at short intervals over a period of 3 hr after the administration, were analysed for total and ionic F. After ingestion of F without Al, there was a rapid increase in salivary F, with peak levels of about 0.2 ppm attained after approximately 50 min. When F was ingested with Al, the rate of increase of salivary F was depressed, and peak levels were reduced. This effect was slight for 3.5 mg Al, somewhat greater for 7.1 mg, and marked for 14.2 mg. No Al was detected in the saliva by spectrographic analysis. Fluorine given as PO₃F^2? gave a slower rise in salivary F, and lower peak levels in 3 of 5 subjects than NaF, but the response to Al was similar. Only ionic F was detected in whole saliva and in samples of parotid saliva collected after ingestion of PO₃F^2?. It is concluded that Al interferes with gastrointestinal absorption of F by forming poorly absorbable Al-F complexes, and that PO₃F^2? is subjected to hydrolysis prior to absorption of F. The findings suggest that the Al normally present in food and beverages may affect gastrointestinal absorption of F.     

Positive and negative bacterial associations involving Dialister pneumosintes in primary endodontic infections

Dialister pneumosintes is an anaerobic Gram-negative rod that has been recently implicated as a candidate endodontic pathogen. In this study, samples taken from abscessed teeth and infected root canals associated with asymptomatic or symptomatic periradicular lesions were examined for the occurrence of bacterial associations involving D. pneumosintes. DNA was extracted from the samples, and the presence of D. pneumosintes and 16 other bacterial species was determined by means of species-specific nested polymerase chain reaction. Positive and negative associations involving D. pneumosintes were investigated by computing the odds ratio of D. pneumosintes being found in a sample from endodontic infection in co-infection with one of the other target species. The association between the pairs containing D. pneumosintes and the occurrence of pain also was evaluated. D. pneumosintes was always detected in mixed infections with at least two of the other target species. D. pneumosintes was positively associated with Treponema denticola, Porphyromonas endodontalis, Fusobacterium nucleatum, Peptostreptococcus micros, Campylobacter rectus, Prevotella intermedia, T. pectinovorum, and T. vincentii. Negative associations were observed with Bacteroides forsythus, P. gingivalis, and Actinomyces israelii. No pair containing D. pneumosintes was found to be significantly associated with symptomatic cases (p > 0.01). The findings of this study lend considerable support to the notion of D. pneumosintes being an important endodontic pathogen, usually in a mixed infection. Positive associations of this species with other highly prevalent species, such as T. denticola and P. endodontalis, suggest that bacterial synergism can occur and thereby play an important role in the pathogenesis of different forms of periradicular lesions.     

Ten-year outcome of porcelain laminate veneers placed within the general dental services in England and Wales

Aim

It is the aim of this paper to consider the factors associated with the need for re-intervention on teeth restored with porcelain veneers.

Methods

A data set was established consisting of adult patients (18 years or older) whose restoration records contained the placement of one or more porcelain laminate veneers. For each tooth treated with a porcelain veneer, the subsequent history of intervention on that tooth was consulted, and the next date of intervention, if any could be found in the extended data set, was obtained. Thus a data set was created of porcelain veneers which have been placed, with their dates of placement and their dates, if any, of re-intervention.

Results

Data for over 80,000 different adult patients were analysed, of whom 46% were male and 54% female. A total of 2562 porcelain veneer restoration occasions in 1177 patients were obtained from the data over a period of 11 years.Factors which were found to influence the survival of porcelain veneers include patient gender, patient age, changing dentist, patient's treatment need, patient charge-paying status and geographical area.

Conclusions

While dentist factors do not appear to play a part, a variety of patient factors have been found to influence veneer survival to re-intervention. Overall, 53% of porcelain veneers in the study survived without re-intervention at 10 years.     

3H]-forskolin binding sites in rat submandibular salivary glands

Specific [3H]-forskolin binding was linear as a function of the membrane protein concentration and reached steady-state by 30-40 min of incubation at 37 degrees C. Such binding was saturable and the bound radioligand could be readily dissociated by an excess of unlabelled forskolin. There was only one type of binding site, with a dissociation constant (Kd) of 0.16 microM. The concentration of the binding sites (Bmax) was 0.73 pmol/mg protein. There was no significant difference in the [3H]-forskolin binding characteristics in membranes of rats fed for 6 weeks on diets containing 10% corn oil, 8% coconut oil + 2% corn oil, or 10% menhaden fish oil.     

Assessing the quality of clinical and administrative data extracted from hospitals: the General Medicine Inpatient Initiative (GEMINI) experience

ObjectiveLarge clinical databases are increasingly used for research and quality improvement. We describe an approach to data quality assessment from the General Medicine Inpatient Initiative (GEMINI), which collects and standardizes administrative and clinical data from hospitals.MethodsThe GEMINI database contained 245 559 patient admissions at 7 hospitals in Ontario, Canada from 2010 to 2017. We performed 7 computational data quality checks and iteratively re-extracted data from hospitals to correct problems. Thereafter, GEMINI data were compared to data that were manually abstracted from the hospital’s electronic medical record for 23 419 selected data points on a sample of 7488 patients.ResultsComputational checks flagged 103 potential data quality issues, which were either corrected or documented to inform future analysis. For example, we identified the inclusion of canceled radiology tests, a time shift of transfusion data, and mistakenly processing the chemical symbol for sodium (“Na”) as a missing value. Manual validation identified 1 important data quality issue that was not detected by computational checks: transfusion dates and times at 1 site were unreliable. Apart from that single issue, across all data tables, GEMINI data had high overall accuracy (ranging from 98%–100%), sensitivity (95%–100%), specificity (99%–100%), positive predictive value (93%–100%), and negative predictive value (99%–100%) compared to the gold standard.Discussion and ConclusionComputational data quality checks with iterative re-extraction facilitated reliable data collection from hospitals but missed 1 critical quality issue. Combining computational and manual approaches may be optimal for assessing the quality of large multisite clinical databases.