A high-resolution radiation hybrid map of the human genome draft sequence.

We have constructed a physical map of the human genome by using a panel of 90 whole-genome radiation hybrids (the TNG panel) in conjunction with 40,322 sequence-tagged sites (STSs) derived from random genomic sequences as well as expressed sequences. Of 36,678 STSs on the TNG radiation hybrid map, only 3604 (9.8%) were absent from the unassembled draft sequence of the human genome. Of 20,030 STSs ordered on the TNG map as well as the assembled human genome draft sequence and the Celera assembled human genome sequence, 36% of the STSs had a discrepant order between the working draft sequence and the Celera sequence. The TNG map order was identical to one of the two sequence orders in 60% of these discrepant cases.

Dental and oral complications of lip and tongue piercings.

Piercing of the tongue and perioral regions is an increasingly popular expression of body art, with more patients coming in for a routine check-up with tongue and/or lip piercings. Several complications of oral piercing have been reported, some of which are life-threatening. In the present clinical survey the prevalence of both tongue and lip piercing complications in oral health was assessed in a group of 50 patients. The most common dental problem registered was chipping of the teeth, especially in association with tongue piercing. Gingival recession was seen as a result of lip piercing with studs. Post-procedural complications included oedema, haemorrhage and infection. Therefore, dentists and oral and maxillofacial surgeons should be given more authority to advise patients with oral and facial piercings or those who plan to acquire this type of body art.

Fluoride release profiles of mature restorative glass ionomer cements after fluoride application.

This study investigates the fluoridation of four conventional glass ionomer cements (GIC) (ChemFil Superior encapsulated, Fuji Cap II, Ketac-Fil and Hi Dense) and three resin-modified GIC (RM-GIC) (Fuji II LC encapsulated, Photac-Fil and Vitremer). The fluoride release of matured restorative GIC was measured as a function of time, after four repeated fluoridations in a 2% NaF aqueous solution for 1 h. This release was corrected for the intrinsic release as determined with a control group. It was demonstrated that application of fluoride is capable of recharging GIC but the subsequent high fluoride release only lasts for one or a few days. Moreover, the fluoride release behaviour depends on the cement formulation. Comparable to the intrinsic release, the net fluoride release after fluoridation is composed of a short- and a long-term process, the former being predominant after fluoridation. The total amount of fluoride released according to the short-term process increases with consecutive fluoridations. This is especially pronounced for the RM-GIC, who exhibit a relatively slow release after fluoridation as compared to the conventional GIC. An explanation for these results is suggested on the basis of the physicochemistry of the setting reaction of the cements and of the fluoridation process.

Fluoride release process of (resin-modified) glass-ionomer cements versus (polyacid-modified) composite resins.

The fluoride release of conventional and resin-modified glass-ionomers is reviewed and compared to that of fluoride-releasing (polyacid-modified) composite resins. Each formulation displays a typical fluoride release profile. The cumulative amount of fluoride released is described by [F]c = [F](I)t/(t + t1/2) + beta square root t for glass ionomers whether resin-modified or not, whereas for composite resins this quantity is given by [F]c = [F](I)t/(t + t1/2) + alpha t. Both equations indicate that two kinetic processes are responsible for the fluoride release profiles. The kinetic parameters [F](I), t1/2, beta and alpha depend on the formulation. On the basis of the exchange characteristics for fluoride, an attempt is made to explain the mechanisms responsible for these fluoride release processes.

Characterization of poly(L-lactic acid) microspheres loaded with holmium acetylacetonate.

Holmium-loaded PLLA microspheres are useful systems in radioembolization therapy of liver metastases because of their low density, biodegradability and favourable radiation characteristics. Neutron activated Ho-loaded microspheres showed a surprisingly low release of the relatively small holmium complex. In this paper factors responsible for this behaviour are investigated, in particular by the use of differential scanning calorimetry, scanning electron microscopy, infrared spectroscopy and X-ray diffraction. The holmium complex is soluble in PLLA up to 8% in films and 17% in microspheres. Interactions between carbonyl groups of PLLA, and the Ho-ion in the HoAcAc complex, explain very satisfactorily the high stability of holmium-loaded microspheres.

Tongue piercing and associated oral and dental complications.

The insertion of metal objects into intraoral and perioral sites is growing in popularity. However, there are numerous oral and dental complications associated with tongue piercing. Fifteen patients with tongue piercings (pierced in the body of the tongue, anterior to the lingual frenum) attending the dental office of the authors, with and without complaints, were clinically and radiographically examined. The most common dental problem registered was chipping of teeth. Furthermore, two cracked teeth and four teeth with cusp fractures were also seen. One case of selective dental abrasion was registered. Trauma to the lingual anterior gingiva was the most common gingival problem. A salivary flow stimulating effect was only reported by 2 of the 15 individuals. None of the patients complained of interference with speech, mastication and swallowing. One case of galvanic currents produced by the appliance was registered. On the basis of the registered data, we concluded that patients need to be better informed of the potential complications associated with tongue and oral piercings, and that the dental profession can serve this role.

Periapical lesions accidentally filled with calcium hydroxide.

AIM: To evaluate the effect of accidental and voluminous calcium hydroxide overextensions into periradicular lesions and tissues on the prognosis of periapical healing. SUMMARY: Eleven cases with periapical lesions and voluminous calcium hydroxide overextension are presented. Despite literature reports on the deleterious effects of calcium hydroxide extension in the periapical area, none of the endodontic treatments failed and surgical intervention was not indicated. KEY LEARNING POINTS: Extensive extrusion of calcium hydroxide into the periapical tissues does not appear to comprise periapical healing. Despite this finding, the deliberate extrusion of dental materials into the apical tissues is not advocated.