Aspects on oral health, paper I

Consequently this leads to, on average, one caries lesion more in our CKD-patients compared to their controls, as seen in Table IV.

Periodontitis

It is shown that plaque retention on teeth surface is far from the primary cause of periodontitis and some researchers point out smoking as a determinant factor ⁴¹. Smoking is definitely connected to a higher risk in terms of periodontitis with a prevalence of 48% in smokers, 32% in ex-smokers, and 20% in non-smokers ⁴². The intricate and complex immune reaction between tooth root, cementum surface, and attaching periodontal ligament still needs more investigation. It is suggested that genetic polymorphism might serve as an explanatory model of the level and kind of immune response to bacterial stimuli in the teeth ligament and the pathological pockets ⁴³. The complex research field of interaction between genetic expression and environmental properties will bring more future knowledge in this matter. When we compared loss of attachment data in our study to other reports we found similar results ^{6, 37-39}.

Systemic inflammatory markers before and after dental treatment The effect on s-albumin and proteinuria before and after an oral treatment of a CKD patient including extraction of infected teeth is seen in Figure 33 and Figure 34. An orthopantomographic x-ray is presented to show the dental status of the patient before treatment (Figure 32).

Figure 32. 50-year-old male with chronic glomerulonephritis.

A 50 year old male with CKD, s-albumin and CRP followed during 14 months, dental treatment at month 7

0 10 20 30 40

1 2 3 4 5 6 7 8 9 10 11 12 13 14 months

konc s-albumin

CRP

Figure 33. S-albumin (g/L), CRP

(mg/L)

Figure 34. Proteinuria (mg/24 h)

We found s-albumin, CRP and proteinuria to normalize during a period of more than six months after dental treatment.

Methodological aspects of Paper I

When we enrolled the HD patients we found that they were difficult to recruit since they already spent a lot of time in the hospital.

Therefore it is important to consider a selection bias, since most likely the healthier and less medically compromised patients

participated. On the other hand, uremic patients with oral symptoms of some kind seemed more motivated to participate, which would lead to a selection bias providing a stronger correlation. We found no problems in recruiting healthy controls for the study.

DMFT and loss of attachment are well known measures used in epidemiological studies and are therefore considered important parameters for descriptions of tooth injuries or loss of teeth. The decision not to use decayed missing filled surfaces can be considered a weakness if the effort had been to obtain a more precise result. Our intention was not to present the actual surfaces affected of caries but only to describe the prevalence of ongoing decay. When describing loss of attachment we did not describe ongoing periodontal disease through pathological pocket formation as this would only describe the loss of attachment from the marginal gingiva to the bottom of the pocket. Our intention was to describe acquired loss of attachment and long-term pathological changes in the periodontium in

correlation to a chronic uremic condition. The long-term influence on oral health is an aspect to be considered, as CKD might

contribute to a faster progression of the periodontal disease ⁴⁴. Investigating mucosal lesions, we registered signs of inflammation on the gingiva, the mucous membranes, and the tongue. Lesions with no inflammation involved were registered in patient files, but not shown in this study. Since many CKD patients are not aware of the fact that they have a greater risk of developing oral diseases they

A 5 0 y e a r o l d m a l e wi t h C K D , p r o t e i n u r i a f o l l o we d d u r i n g 15 m o n t h s, d e n t a l t r e a t m e n t a t m o n t h 7

0 5000 10000 15000 20000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

m o n t h s

pr ot einuria

Education le ve l com paring CKD patie nts to controls

0 5 10 15 20 25 30 35 40 45 50

Education level 9 years or less

Education level 10-12 years

Education level more than 12 years (%)

CKD Controls

patient’s oral health neglect or lack of priority to dental health most likely contributes to a deterioration in oral condition. They have not been referred by their nephrologists to regular dental care except before investigation for transplantation.

The strengths of this study were the number of uremic patients with a GFR <20 mL/min/1.73m² compared to previously published similar reports, and the fact that one experienced dentist examined all patients and controls, therefore minimizing the risk of an information bias 1, 34-36, 40, 45, 46. The PD and HD patient groups became too small to make far-reaching conclusions, although for the HD group we found statistically significant differences of clinically important magnitude in all status outcomes with worse oral

conditions except mucosal lesions.

Confounders influencing oral health

Oral health is affected because of a number of confounding factors ⁴. Although adjusting for age, sex, tobacco habits, diabetes, and type of dialysis treatment, a difference still persists. There are a number of confounders yet to be investigated. Such a factor is the influence of pharmacological drugs used to treat symptoms of kidney failure and comorbid conditions. The possibilities of bias because of diuretics and antihypertensives have earlier been discussed, as have other drugs, for example corticosteroids and antidepressants ⁸. Food intake in CKD patients is described as changing during progression ³. However, in reviewing the literature, there is no evidence for food habits and nutrients influencing the salivary secretion.

Socioeconomic factors are strong confounders for a worse oral health as well as a worse renal outcome in many reports ^{5, 10, 47}. When socioeconomic differences were controlled concerning

education in CKD patients and the controls, we found a difference in CKD patients compared to their controls. The results in Figure 35 demonstrate that although age- and sex-matched, 44% of the CKD patients (n=95) reported nine years or less of education, while only 33% of the controls reported the same level of education. The difference was not statistically significant.

Figure 35. A comparison of education levels in patients with chronic kidney disease and age- and sex-matched controls.

Failing oral hygiene habits when patients have a negatively affected general health is often one explanatory factor for worse oral health ⁴⁸. CKD affects the daily life in many ways, especially when interventions including dialysis are needed. Fatigue and periods of complications from the renal disease increase the risk of oral hygiene neglect.

Oral hygiene was measured in Paper II, and we found a worse oral health outcome in dialysis patients compared to their controls. In Paper II we also found more visible dental plaque formation in CKD patients than controls.