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Dental Drugs
Few of the drugs used in dentistry are likely to cause complications. However, it is good to be aware of their effects in the renal patient. As a rule drug doses need to be reduced in the renal patient as those excreted by the kidneys may have enhanced or prolonged activity. Lignocaine, diazepam and opioids are mainly metabolised by
the liver. However, antimicrobials, analgesics, hypnotics and general anaesthetics may need to be given in lower doses. (4)

Fluorides: Topical fluoride applications need to be used carefully and it is recommended that systemic fluorides are avoided as there is some question about fluoride excretion by damaged kidneys.(5) For
patients receiving haemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD), serum fluoride accumulation is a risk factor(6). Persistent high levels of plasma fluoride in such patients can cause osteodystrophy and other bone damage(7).

Analgesics: The use of aspirin and other non-steroidal anti- inflammatory drugs (NSAIDS) is contraindicated in the renal patient as excretion is delayed. Analgesics that can be safely used include codeine and dihydrocodeine.

Hypnotics and sedatives: Diazepam or choral hydrate can be used. Long acting barbiturates are contraindicated due to delayed excretion. Chlordiazepoxide may cause depression and lethargy and is best
avoided. Antihistamines may cause dry mouth or urinary retention(4).

Anaesthetics: Local anaesthetics appear safe unless there is a severe bleeding tendency. Although local anaesthetic is metabolised by the liver, it is excreted via the kidney and large amounts of local anaesthetic should be avoided. General anaesthetics, however, pose specific problems for renal patients as they are highly sensitive to the myocardial depressant effects. Myocardial depression and dysrhythmias are especially likely in poorly controlled metabolic acidosis. It is recommended that in dental practice local anaesthetic with relative analgesia can be used.(4)

Other Drugs: Antacids containing magnesium salts should not be given as magnesium retention is common in ESRF. Any preparations containing sodium, potassium or calcium should be avoided. Many renal patients are taking a cocktail of drugs including antihypertensives, diuretics, phosphate binders and antacids. All of which may complicate dental management.

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Oral Health
The main oral health problem experienced by renal patients is xerostomia. This is as a result of several factors which include multiple medication, restricted intake of fluids and diabetes, which many renal patients suffer from. Xerostomia may also predispose the patient to caries, mucositis and oral infection as the protective
factors in saliva are not present. For the HD and immunosuppressed transplant patient infections in the oral cavity may act as foci in other sites of the body.(8)

Dialysis patients may form calculus more rapidly than healthy individuals possibly due to high salivary urea and phosphate levels (9). A significant correlation between plaque scores and gingival inflammation in renal dialysis patients has also been reported.(10, 11) Elevated parathyroid hormone synthesis is also common in ESRF
which causes accelerated bone loss. This may also exacerbate periodontal disease.

Transplant patients who are immunosuppressed often experience a change in oral flora. This can predispose the patient to oral candidiasis. In addition cyclosporine and calcium channel blockers are known to contribute to gingival hyperplasia, which is exacerbatedby poor oral hygiene.

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Renal Nutrition
The balance of blood chemistry is fundamentally affected by nutrition and the dietary intake of specific nutrients. The management of the renal patient, therefore, includes dietary restriction and regulation. Initial management aims to lower blood urea levels, balance electrolytes, lower plasma phosphate levels and regulate
fluid balance. Dietary management therefore includes restriction of sodium, potassium and phosphates. Careful protein and fluid balance is also required.

Protein. Dietary protein both contributes to uremic symptoms and promotes the progressive loss of renal function in chronic renal failure (CRF). Patients with CRF spontaneously reduce their intake of
dietary protein as they lose renal function. When the GFR is less than 20 ml/min, aversion to meat is not uncommon. At that level of renal function, the spontaneous intake of dietary protein may be 0.8 g/kg/day or lower. Historically, low-protein diets were prescribed to reduce uremic symptoms. Anecdotal evidence suggests that restriction of dietary protein may relieve specific uremic symptoms, such as itching. However, adherence to a low-protein diet is difficult, and there is controversy as to whether restricting the intake of daily
protein to less than 1 g/kg/day slows the progression of CRF(12).

Phosphorus. Hyperphosphatemia plays a major role in the development of the secondary hyperparathyroidism seen in CRF. Measures for lowering plasma phosphate levels include the restriction of dietary phosphorus, by itself or in conjunction with the use of phosphate binders (e.g., calcium carbonate or aluminum hydroxide) to reduce the absorption of ingested phosphorus. Although the benefits of such measures have not been demonstrated consistently, their use is advisable for treating or preventing hyperphosphatemia in patients
with CRF(11).

Vitamin D. Calcitriol, which is the active form of vitamin D, may be deficient in patients with CRF because of reduction in functional kidney parenchyma and, consequently, diminished hydroxylation of vitamin D. In modest doses (0.25 to 1 mg daily), calcitriol may reduce secondary hyperparathyroidism and improve bone histology. However, incautious use of calcitriol may cause hypercalcemia, which can worsen kidney function. On balance, use of calcitriol should beundertaken only with appropriate monitoring and an awareness of the
potential hazards(11).

Sodium. About 2-4 g/day is allowed, depending on the stage of CKD. Sodium restriction is especially important for the elderly. A low- salt diet can delay the progression of CKD in these salt-sensitive
individuals. Potassium may also need to be restricted in the late stages of CKD.


Conclusion
As the incidence of renal failure increases, patients receiving HD and transplant recipients will become more common in the dental practice. These patients require special attention with regard to bleeding tendencies, risk of infection, xerostomia and multiple medication use. When treating these patients it is also good to bear
in mind that some may be pre-occupied with the treatment of their renal disease and have a tendency to neglect preventive oral health measures. Patients may also experience stress in trying to comply with the extensive dietary restrictions and medication programs, which may also contribute to anxiety and aversion to further
preventive instruction. In addition to good oral health promotion, there is an increased need for collaboration between the dental and medical professions to provide safe and appropriate dental care for these patients.

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Footnotes
Table 1
Abnormalities in dialysis and post-transplant patients

• bleeding tendencies ( dialysis patients are heparinized)

• impaired drug excretion

• hypertension

• infections

• anaemia (particularly dialysis patients)

• renal osteodystophy

• dysrhythmias ( due to hyperkalaemia and elevated potassium)

• immunosuppressive therapy (post transplant patients)

1. E. Davidovich, Z. Schwarz, M. Davidovitch, E. Eidelman and E.
Bimstein Oral findings and periodontal status in children,
adolescents and young adults suffering from renal failure J Clin
Period. 2005. 32:10:1076

2. National Kidney Federation

3. Naylor GD., Hall EH.,et al: The patient with chronic renal failure
who is undergoing dialysis or renal transplantation: another
consideration for antimicrobial prophylaxis. Oral surg Oral Med oral
Pathol 1988 Jan;65(1):116-21

4. Scully.C. Cawson.R.A., Medical Problems in Dentistry 4th ed Wright
Press. 2002 pp258

5. Scully.C. Cawson.R.A., Medical Problems in Dentistry 4th ed Wright
Press. 2002 pp259

6. al-Wakeel JS, Mitwalli AH, Huraib S et al: Serum ionic fluoride
levels in haemodialysis and continuous ambulatory peritoneal dialysis
patients. Nephrol Dial Transplant. 1997 Jul;12(7):1420-4.

7. Petifor J.M.,Schnitzler C.M et al: Endemic skeletal fluorosis in
children: hypocalcemia and the presence of renal resisitance to
parathyroid hormones. Bone Min 1989 7:275-288

8. Goldman M., Vanherwerghem JL.: Bacterial infections in chronic
hemodialysis patients: epidemiologic and pathophysiologicaspects.
Advan Nephrol Necker Hosp. 1990;19:315-32.

9. Epstein SR., Mandel I.,Scoop IW.: Salivary composition and
calculus frmation in patients undergoing hemodialysis. J Periodontol
1980 Jun;51 (6):336-8

10. Naugle K., Darby ML., Bauman DB et al: The oral health status of
patients on renal dialysis. Ann Periodontol 1998 Jul;3(1):197-205

11. Atassi F., Al-Shammery RA.,Al-Ghamdi S: Gingival health among
individuals on hemodialysis in Saudi population. Saudi Dental J
2001;13(2):82-86

12. Cohen, E. P. Chronic Renal Failure and Dialysis ACP Medicine
2004. © 2004 WebMD Inc.