Oral medicine Hepatitis. Implications for dental care

Demas PN, McClain JR Oral Surg 1999; 88: 2–4

A history of hepatitis is not only indicative of a possible infection risk, but may also compromise or complicate dental treatment, as detailed in this review.

Currently there are 6 different hepatitis viruses, termed A, B, C, D, E and G. A and E are mainly transmitted by the faecal-oral route, and are usually mild infections without a carrier state. G is possibly related to C, and is transmitted in blood products. D requires the presence of B for infection, and exacerbates the serious B infection. C is clinically inactive in 95% of patients, but causes the commonest form of chronic hepatitis. B causes a carrier state in 10% of infections, usually without clinical symptoms.

Liver damage resulting from hepatitis (and other causes such as alcohol abuse) may cause bleeding problems by reducing coagulation factor synthesis, and also immune dysfunction. There may be associated renal dysfunction, and gastrointestinal bleeding leads to increased bacterial production of ammonia which may cause encephalopathy.

In addition, medication may be affected in various ways: IV narcotics and barbiturates may exacerbate CNS depression, and some analgesics, antibiotics and LA agents may have altered effects because of reduced hepatic drug metabolism and reduced liver synthesis of albumin, to which many drugs bind.

Periodontology; genetics Loss-of-function mutations in the cathepsin C gene result in periodontal disease and palmoplantar keratosis

Toomes C, James J et al. Nature Genet 1999; 23: 421–424

In 8 families affected with Papillon-Lefèvre syndrome, these investigators found a genetic variation resulting in a severe deficiency of an important protease.

Papillon-Lefèvre syndrome is a rare autosomal recessive disorder consisting of severe early-onset periodontitis and hyperkeratosis on the palms of the hands and soles of the feet. These investigators examined affected and unaffected individuals in 8 families, and compared their genes in a small area on chromosome 11, which previously had been reported to contain a possible locus associated with the syndrome.

These investigators examined the region of chromosome 11q14-q21 with 6 markers and narrowed the candidate region to a much smaller interval. Within this interval is also found the gene which codes for lysosomal cathepsin C, a powerful protease. Further investigation showed that all affected subjects had severely reduced leucocyte production of this protease. This finding is fascinating, because periodontitis specifically requires increased protein destruction, rather than its reduction.

Oral medicine Burning mouth syndrome: prevalence and associated factors

Bergdahl M, Bergdahl J J Oral Pathol Med 1999; 28: 350–354

The condition appears more frequent in women than in men, and a variety of factors may help to explain it.

This syndrome consists of a burning sensation in the oral cavity despite clinically normal mucosa. A variety of clinical and psychological factors have been associated with it. A random selection was made of 1,000 men and 1,000 women, from a Swedish population of 48,500, of whom 70% agreed to participate in the study. Eleven men and 42 women complained of the condition, and were interviewed and examined. No men had the syndrome before the 5th decade, but in women it was found in the 4th decade. In more than 2/3 cases, the tongue was the site involved, but all other mucosal sites were represented in a few cases. In 2/3 individuals, oral dryness was a subjective complaint, which the authors note may relate to medication or depression.

Out of a wide range of variables associations were found with: subjective dryness, age, medication, taste disturbance, L-thyroxine intake, stimulated salivary flow, depression and anxiety. There was no relationship with pain intensity on a visual analogue scale. The authors consider the syndrome to be a marker of illness and/or distress.

Orthodontics Cheek and tongue pressures in the molar areas and the atmospheric pressure in the palatal vault in young adults

Thüer U, Sieber R et al. Eur J Orthod 1999; 21: 299–309

This study gives further evidence on the determinants of tooth position.

This study aimed to clarify previous findings on pressures within the mouth, by using a method designed to produce simultaneous buccal and lingual measurements at specified positions on upper and lower left posterior embrasures, and also at the highest point of the palatal vault. These pressures are of significance in the aetiology of malocclusion and provision of post-orthodontic treatment retention.

In 12 dental students of each gender, pressures were measured accurately on two separate occasions at rest, during chewing and during swallowing. For these 3 conditions, mean pressures in g/sq cm at lower lingual, lower buccal, upper lingual, upper buccal and palatal positions were respectively: 2.2, 2.5, 1.4, 2.7, and 0.1; 82, 33, 60, 35 and 32; 183, 68, 196, 68 and 89.

Biological variation of individuals was large, and it was clear that half the subjects had a negative pressure in the vault at rest. There were no correlations between this pressure and resting pressures on teeth. An inverse relationship between vault and mandibular buccal pressure while swallowing suggested an increased pressure on the teeth during this act.