Evaluation of radiopaque denture liner

Impacted dentures in the oesophagus

Objective:

This study presents the incidence of denture impaction in the oesophagus, and discusses the difficulties of managing such cases.

Method:

A total of 262 patients with a history of foreign body ingestion (between 1999 and 2010) were reviewed; 46 of these patients had dentures impacted in the oesophagus.

Results:

The cervical section of the oesophagus was the commonest site of impaction. Dysphagia and tracheal tenderness were the most consistent features when dentures became impacted in the upper oesophagus. In most cases, rigid oesophagoscopy enabled successful removal of the impacted denture. Locating an impacted denture hidden within the oesophageal mucosal folds sometimes proved difficult.

Conclusion:

In cases of impacted dentures in the oesophagus, a positive history helps in the diagnosis, but a high degree of clinical suspicion aids early detection. Conventional radiographs are important but may not always be of assistance. Early intervention reduces complications. Dentures that are poorly maintained and old are more likely to be swallowed accidentally. The inclusion of radiopaque filler within dentures would assist localisation following accidental swallowing.

Aluminium radiopacity standards for dentistry: an international survey

OBJECTIVE

The aims of this study were to determine the appropriate composition and purity limits of aluminium alloy radiopacity standards for dental biomaterials, taking into account the current status in representative laboratories worldwide, and to formalise the calculation procedure for processing radiopacity data.

METHODS

A series of aluminium step-wedges were obtained from academic and industrial research laboratories. These were analysed by energy dispersive X-ray procedures. The set of step-wedges were independently characterised for radiopacity at two University dental schools.

RESULTS

The percentage of aluminium together with the percentages of minor alloying elements (magnesium, manganese, iron and silicon) have been determined as mass percentages. For each centre, the optical density versus step-height for all wedges was judged to fall on a common curve, with the main exception of one step-wedge that was found to contain 4% copper, by mass. A suitable calculation procedure was described explicitly.

CONCLUSION

Of the examined representative step-wedges, all but the aluminium--4% copper material were satisfactory and gave results comparable with wedges of high purity. Limits should therefore be revised for composition of aluminium radiopacity step-wedges or test blocks to a more realistic level of purity. Alloys with more than 0.05% copper or 1.0% iron should be excluded and the aluminium content should be at least 98% by mass. In the calculations deployed for deriving radiopacity as 'equivalent aluminium thicknesses', an appropriate linear regression procedure should be employed and considerable care taken in the evaluation of materials of low or borderline radiopacity, relative to specification limits. The method described is principally suitable for materials with radiopacity greater than 1 mm. For materials with radiopacity less than 1 mm aluminium, thicker specimens (2 mm) should be used.