dialysis is also available as an alternative and effective lifesaving treatment in end stage renal failure . patients who received renal transplant have a better life in comparison to dialysis patients as a longer lifespan and less comorbidity . however , there are still some concerns about the survival rate . the increase of life expectancy in renal transplant patients has an impact on oral and dental health services . different oral and dental problems arise in these patients , most of which develop as a consequence of drug - induced immunosuppression [ 3 , 4 ] . immunosuppressant treatment depresses the cell - mediated immune response , producing antibodies , monocytes , neutrophils , natural killer cells and complement . for the clinician , this means a greater risk of oral infection and other associated complications . when the immune system suppress , microbial agents of normal oral flora have an opportunity to become pathogen and make infection and destruction in the oral cavity . oral lesions may also develop as a result of side effects and drug interactions during immunosuppressive therapy . the oral manifestations associated with immunosuppressive drugs are gingival hyperplasia , xerostomia , dental caries , periodontal diseases , dental anomalies , opportunistic infections such as oral candidiasis and hairy leukoplakia , squamous cell carcinoma of the lips and non - hodgkins lymphoma [ 79 ] . gingival enlargement may be caused by cyclosporine and calcium channel blocker application that begins initially from the interdental papilla and anterior labial regions [ 1012 ] . depending on the high prevalence of oral manifestations after renal transplantation , the patients must undergo regular oral examinations by dentists in order to diagnose and treat any suspicious lesion . establishment of proper oral hygiene procedures in these patients may prevent oral lesions to some extent . rosa - garsia and colleagues ( 2005 ) found that 60% of renal transplant patients had at least one oral lesion . gulec and haberal ( 2006 ) reported the prevalence of some oral lesions such as gingival hyperplasia and oral candidiasis in renal transplant recipients . although there are a few studies that reported oral lesions in renal transplant patients in iran , there is no comparison between the prevalence of oral lesions in dialysis patients and recipient renal transplant patients . so the objective of the present study was to compare the prevalence of different oral lesions in patients receiving renal transplant and candidates of renal transplantations in two centers in tehran , iran . this cross - sectional study was performed on 93 patients who had received renal transplantation in 2 hospitals in tehran from 2001 to 2008 . the subjects were selected from their records at the hospital centers , and information on age , gender , date of receiving transplant , dialysis duration and patient medications were extracted from the patients medical records . all patients were invited to come to the dental unit of imam khomeini hospital at the specified visit time by calling them . oral examination was done on the dental unit and oral lesions were diagnosed clinically by an oral medicine specialist . xerostomia was diagnosed objectively by the  tongue - blade  test ; sticking a tongue - blade on the oral mucosal surfaces indicates that the mucosa is not sufficiently moisturized by the saliva and also subjectively by the patients complaints of difficulty in chewing , swallowing , speaking and denture retention . pseudo membranous candidiasis was diagnosed based on whitish or yellowish plaques throughout the oral mucosa that could be easily scraped off . erythematous candidiasis was diagnosed if the burning mouth sensation was accompanied by a diffuse loss of filiform papillae of the dorsal tongue , resulting in a reddened  bald  appearance of the tongue . the diagnosis of recurrent aphthous stomatitis was made by clinical presentation and squamous papilloma was confirmed by biopsy . the patients in both case and control groups underwent oral examinations and the results were analyzed by chi - square test to compare oral manifestations in both groups and spearman correlation coefficient to determine the relationship between related drugs and oral manifestations . a p value less than 0.05 was considered as significant . ninety - three renal transplant recipients , of which 52 were men ( 55.9% ) and 41 were women ( 44.1% ) with a mean age of 40.613.8 ( range 1466 ) years were examined . in addition , 93 patients ( 59 men , 63.4% ) with a mean age of 50.0315.1 ( range 1180 ) years who received dialysis were recruited as the control group . the mean time after receiving renal transplantation was 3.302.45 ( range 18 ) years . in the control group , the mean time from the diagnosis of end stage renal failure in the case group was 1.841.86 years before renal transplantation and in the control group it was 5.76.6 years . drug administration in renal transplantation patients was in the following order : all the patients were receiving corticosteroids . 97.80% , 29% and 17.2% of them were receiving cyclosporine , amlodipine and azathioprine , respectively . in the control group , on oral examination , at least one lesion was found in 30 ( 32.2% ) patients of the renal transplant group and 8 ( 8.6% ) patients in the control group . the most common oral manifestation was xerostomia being observed in 20 ( 21.5% ) patients in the case group and 4 ( 4.3% ) patients of controls ( table 2 ) . gingival enlargement was reported in three renal transplant cases ( 3.3% ) and one of the controls ( 1.1% ) . minor aphthous was found in five ( 5.4% ) patients of the case group and squamous papilloma was detected in one patient of the control group ( 1.1% ) . sixty patients in the case group ( 67.7% ) and 85 patients in the control group ( 91.4% ) did not show any oral manifestation . the difference between the two groups was analyzed by chi - square test and it was statistically significant ( p < 0.0001 ) . the odds ratio of different offending medications and the effect of these in increasing the risk of oral lesions in renal transplant recipients is shown in table 3 . endodontic the prevalence of oral lesions was higher in renal transplant patients compared with the dialysis group . one of the possible causes may be immunosuppressive drugs . in general , 32.3% of renal transplant recipients and 8.6% of the control subjects exhibited oral lesions . in addition , according to statistical analysis , the difference between the two groups was significant . in the present study , dirschnabel and associates ( 2011 ) also showed that the most prevalent oral lesion was xerostomia . the reasons for xerostomia are dehydration , mouth breathing and side effects of the related drugs after renal transplantation such as cyclosporine and nyphidipin . symptoms of xerostomia are burning sensation of the oral mucosa , difficulty in swallowing , mastication and speaking , dysgeusia and an increased prevalence of dental caries . patients require more frequent dental visits and must work closely with their dentists to maintain optimal dental health . our study showed the presence of xerostomia in 4.3% of dialysis patients and 21.5% of renal transplant recipients . this frequency is lower than the study conducted by kho and associates ( 32.9% ) as well as the study performed by udayakumar and collegues ( 31% ) . gingival enlargement ( ge ) was another oral lesion in 3.2% of renal transplant recipients and 1.1% of dialysis patients . it may be caused by cyclosporine that was reported in most of the previous studies . additionally , most of the studies explained the synergistic effect of calcium channel blocker in the development of ge . usually it is limited to the attached gingiva , but it can extend coronally and interfere with occlusion , mastication and speaking . in this study , but the frequency of ge was lower compared to the previous studies [ 3.2% ] . in addition , it was found in 7.25% of the patients in a study carried out by cezario and colleagues . king and colleagues reported higher percentage of ge in renal transplant recipients in contrast of this study . interestingly , al - mohayaa and colleagues reported ge in 74% of their renal transplant patients . regarding the great number of medications taken by the patients and the low frequency of ge in this study , it was impossible to evaluate the effects of each drug on ge . furthermore , ge may be caused by the synergistic effect of cyclosporine and calcium channel blockers . hypertension is one of the most common side effects of immunosuppressive drugs such as cyclosporine ; so calcium channel blockers can be effective in these patients . they can cause ge independently ; however , in combination with calcineurin inhibitors like cyclosporine or tacrulimus , they may have synergistic effects on gingival tissues . the mechanism of action of calcium channel blockers is reducing free calcium in the cytoplasm by blocking calcium channels . synthesis and the releasing process of collagenase and metalloproteinases from gingival fibroblast are calcium - dependent stages . furthermore , administration of these drugs inhibits collagenolysis by interrupting the synthesis and release of collagenase . imbalance between production and break - down of collagen could be one of the ge development - related mechanisms in kidney transplant recipients . al - mohaya and associates have proposed the elevated level of blood glucose as another influential factor in the development of ge in kidney transplant recipients . the presence of diabetes mellitus as an undergoing disease in some of these patients is expectable . in addition , the individuals genetic potentials against long - term drug metabolites , the degree of gingival sensitivity to drugs , and previous gingival conditions such as inflammation are the other potential variables in the incitement of ge in different individuals . the lower frequency of ge in this study compared to others may be attributed to pretransplant examinations , control of oral conditions and encouraging patients to use oral hygiene aids . the results of this study displayed minor aphthous stomatitis in 5.4% of renal transplant recipients as well as pseudomembranous candidiasis in 2.2% of them . sahebjamee and colleagues reported oral candidiasis in 16% of their patients . in spite of the great discrepancy in the frequency of oral candidiasis between these two mentioned studies , the majority of oral candidiasis was caused by the pseudomembranous type al - mohaya et al . found oral candidiasis in 15.5% of the renal allograft recipients . gupta and colleagues also reported it in 10.5% of their patients . regarding the complexity of oral candidiasis pathogenesis , consuming high doses of immunosuppressive drugs in the first three months after renal transplantation may predispose patients to opportunistic infections . also , reduction of salivary flow as a side effect of antihypertensive drugs is one of the risk factors for oral candidiasis in renal transplant recipients . reduction of salivary flow causes a reduction in salivary proteins like immune globulins and the absence of the washing potential of saliva causes decreasing resistance to different infections in the oral cavity . xerostomia , minor aphtous ulcers , ge and candidiasis are the most common oral lesions that were found in renal transplant patients . as these lesions may have various effects on different aspects of life in these patients , it seems necessary that an oral medicine specialist should be present in the team of renal transplant clinicians . therefore , it is recommended that any oral lesion should be eliminated before transplantation and the patients should undergo regular oral examinations in order to diagnose any suspicious lesions .
objective : renal transplantation is performed in patients with end stage renal disease as the best treatment plan . however , different complications may occur in these patients due to the direct consequences of the renal disease or drug - induced suppression of the body immune system . the main objective of the present study was to compare different oral lesions in patients receiving renal transplantation with the patients undergoing dialysis referred to two hospitals in tehran , iran.materials and methods : in this cross - sectional study , 93 renal transplant patients who had received renal transplant at least 6 months prior to our study , were selected from their records at the hospitals . 
 furthermore , 93 candidates of renal transplantation were selected as the control group . 
 the patients in both case and control groups underwent oral examinations and the results were analyzed by chi - square test and spearman correlation coefficient.results:at least one oral lesion was found in 30 ( 32.2% ) patients in the renal transplant group and 8 ( 8.6% ) patents in the control subjects . 
 the difference between the two groups was statistically significant ( p<0.0001 ) . 
 the most prevalent lesion was xerostomia observed in 20 patients of the renal transplant group and 4 patients in the control group . 
 the odds ratio of cyclosporine and amlodipine and the effect of these in increasing the risk of oral lesions was 1.21 and 1.02 , respectively in renal transplant recipients.conclusion:the results of the study showed that renal transplantation significantly increases the risk of related oral lesions 
 . therefore , renal transplant recipients must undergo regular oral examinations in order to find any suspicious lesion(s ) as soon as possible to treat them .