Oral Health In The Renal Patient
Following the publication of a new study, Juliette Reeves explores the link between periodontal disease and patients receiving dialysis.

A new study reported in the latest edition of the Journal of Clinical Periodontology(1) has revealed that patients suffering from end-stage renal failure (ESRF) and those receiving dialysis are more prone to periodontal disease and other oral health problems. Davidovich et al found that the renal failure groups had higher gingival index (GI) and bleeding, probing depths, attachment loss, hypoplasia and  obliteration and less caries, than the control. Plaque was higher in the dialysis and pre-dialysis (PD) groups. The research group
concluded that dialysis duration and end-stage renal failure significantly correlated with gingivitis, probing depth, attachment loss and enamel hypoplasia.

Worldwide more than three million people suffer from renal failure and the global incidence of end stage renal failure (ESRD) is growing at about eight percent annually.

Dental Treatment
End stage renal failure is a life threatening condition. The kidneys regulate fluids, excrete nitrogenous waste, synthesise vitamin D and erythropoietin (EPO), maintain acid-base homeostasis regulate mineral and electrolyte balance and regulate the metabolism and excretion of drugs. All of these things can affect dental treatment due to the resulting abnormalities. See Table 1. Dialysis patients are heparinized and so in order to avoid abnormal bleeding tendencies, treatment should be carried out the day after dialysis. The patient has the maximum benefit from the dialysis and the effect of the heparin has worn off. For the transplant patient only emergency treatment should be carried out within the first three months after transplantation. It is also suggested that transplant recipients should receive antibiotic prophylaxis prior to dental treatment(3).

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.

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 exacerbated by poor oral hygiene.

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 be undertaken 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.

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 Medicine2004. © 2004 WebMD Inc.

News Updates