159Archivio Italiano di Urologia e Andrologia 2018; 90, 3 ORIGINAL PAPER Do dental calculi predict the presence of renal stones? Bulent Kati 1, Ergin Kalkan 2, Eyyup Sabri Pelit 1, Ismail Yagmur 1, Halil Çiftçi 1 1 Department of Urology, Harran University Faculty of Medicine, Sanliurfa, Turkey; 2 Cagri Dental Hospital, Dental Clinic, Elazig, Turkey. Objective: Pathological calcifications that occur in various parts of the body may cause stone formation over time. The structure of these stones is simi- lar in many regions of the body. We have studied the relation- ship between dental calculi and kidney stones. Material and methods: A total of 183 patients with dental stone complaints or dental calculi were included between April and August 2016 in the Cagri Dental Hospital, Elazig, Turkey. Patients were evaluated with regard to a urinary tract ultra- sonography, urinalysis, oral hygiene, and stone and surgical disease history. All information was statistically investigated. Results: The age of the patients in the kidney stones group was significantly higher than the non-kidney stone patients (p < 0.05). In the group with kidney stones, the percentage of dental calculus formation was significantly higher than the group without stones (p < 0.05). In the groups with and without kidney stones, dental stone recurrence rates did not differ sig- nificantly (p < 0.05). Urinary pH was significantly lower in the group with stones than the group without stones (p < 0.05). Conclusions: During a physical examination, the formation of a visible stone, such as a dental calculus, may be an indicator of other types of stones, such as kidney stones, and this should be further investigated. KEY WORDS: Renal stone; Dental calculi; Stone formation; Etiology. Submitted 16 May 2018; Accepted 5 July 2018 Summary No conflict of interest declared. ments (such as a periodontal scaler). Calculi are com- posed of both inorganic (mineral) and organic (cellular and extracellular matrix) components. The mineral por- tion of a calculus ranges from 40-60%, depending on its location in the dentition, and consists primarily of calci- um phosphate crystals organized into four principal mineral phases: octacalcium phosphate, hydroxyapatite, whitlockite, and brushite. The organic component of a calculus is approximately 85% cellular and 15% extra- cellular matrix (3). Renal stones, which are part of a multifactorial disease, are some of the most common problems in modern soci- ety and may affect 12-15% of the population with obser- vation of an increase in their prevalence. Renal stones are more common in males and are categorized into calcare- ous (calcium containing) stones, which make up 90% of all stones, and non-calcareous stones. Most stones (85%) primarily contain calcium oxalate (CaOx) admixed with calcium phosphate (CaP) in the form of apatite or brushite, or occasionally uric acid; however, less com- monly they can be composed primarily of CaP. Although many systemic diseases, such as primary hyperparathy- roidism, bowel disease, and renal tubular acidosis, can result in calcium stone formation, the majority of calci- um stones are found in people with no systemic illness (4). Although many inherited and systemic diseases are associated with calcium renal stones, most stones are idiopathic (5). In this study, we aimed to evaluate the presence of kid- ney stones in patients with dental calculus. This was per- formed according to the dental plaque density in patients who were treated at the same time in the urolo- gy clinic. We also aimed to uncover any relationships between these conditions. MATERIALS AND METHODS The study group was composed of 183 patients (86 females and 97 males) with an age range from 20 to 65 years. We randomly evaluated dental patients who were diagnosed with dental calculus. Based on the amount of plaque, patients were divided into three categories. For the purposes of X-ray assessments of the jaw, panoram- ic, and retroalveolar region, X-rays in suspicious teeth were made. For the realization of the set objective, visu- al analyses of the X rays were conducted (Figure 1). Dental calculus amounts that are generally below 25% DOI: 10.4081/aiua.2018.3.159 INTRODUCTION In dentistry, a calculus or tartar is a form of hardened dental plaque. These are caused by the precipitation of minerals from saliva and gingival crevicular fluid in plaque on the teeth. This precipitation process kills the bacterial cells within the dental plaque, but the rough and hardened surface that is formed provides an ideal surface for further plaque formation. This leads to a cal- culus build up, which compromises the health of the gingiva. A calculus can form both along the gum line (supragingival) and within the narrow sulcus between the teeth and the gingiva (subgingival) (1). Calculus formation is associated with a number of fac- tors including sex, age, bad breath, receding gums, and chronically inflamed gingival (2). Brushing and flossing can remove the plaque from which a calculus forms. However, once formed, it is too hard and firmly attached to be removed with a toothbrush. Calculus buildup can be removed with ultrasonic tools or dental hand instru- Kati_Stesura Seveso 04/10/18 11:58 Pagina 159 Archivio Italiano di Urologia e Andrologia 2018; 90, 3 B. Kati, E. Kalkan, E. Sabri Pelit, I. Yagmur, H. Çiftçi 160 are termed as “low category,” tartar amounts from 25- 75% as “medium category,” and as “high category” those amounts between 75-100% (Figure 2). After the dental examination, all patients were evaluated with a urinary tract ultrasound and urinalysis (Figure 3). Fasting second morning specimens were collected from all individuals who had been fasting since 9:00 p.m. the preceding evening. The dental brushing habits of the patients were evaluated in terms of oral hygiene, addi- tional disease, and stone story. All information was col- lected to determine the incidence of dental calculus and kidney stone in patients. Statistical analysis Mean, standard deviation, median lowest and highest, frequency, and ratio values were used in the descriptive statistics of the data. The distribution of the variables was measured by the Kolmogorov-Smirnov test. The Mann- Whitney U test was used in the analysis of quantitative data. The chi-square test was used in the analysis of qual- itative data. The SPSS 22.0 program was used for all sta- tistical analyses. RESULTS The data from all patients were evaluated together (Table 1). The age of the patients in the kidney stone group was significantly higher than that of the non-kid- ney stone group (p < 0.05). The proportion of patients with renal stones who were males was significantly high- er than the group without kidney stones (p < 0.05). The dental calculus formation was more prevalent in those without renal stones (p < 0.05). In the groups with and without kidney stones, dental stone recurrence rates did not differ significantly (p > 0.05). Urinary pH was sig- nificantly lower in the group without stones (p < 0.05) (Table 2). In the univariate model, there was a significant difference (p < 0.05) in the age, sex, tooth stone percentage, tooth brushing habits, recurrence frequency, presence of addi- Table 1. Characteristics of patients being treated for dental calculi. Figure 1. X-ray views of dental calculi (arrows). Figure 2a, b, c. Appearance of dental calculus during a physical examination. Figure 3. The appearance of kidney stones and crystals in the kidney ultrasound (arrows). Kati_Stesura Seveso 04/10/18 11:58 Pagina 160 tional disease, oral hygiene level, stone story, and urinary pH values. In the multivariate model, significant and independent (p < 0.05) efficacy was observed in the age of the patients, the percentage of tooth stones, and the stone story, suggesting stone formation (Table 3). DISCUSSION Most of the stones in our bodies can be defined as patho- logical calcifications. In the literature, there are thou- sands of articles associated with calcifications occurring in the body, however, this amount is less than the num- ber of articles attempting to explain the relationship between them. Stones occurring in different organs resemble their structure suggesting a metabolic disorder that underlies the process of their formation (6, 7). The components of stone formation are similar in many organs (8). Davidovich E. et al. evaluated the correlation between dental calculus and disturbed mineral metabo- lism in pediatric patients with chronic kidney disease. They suggested that there is a possible association between the severity of renal dysfunction in young patients and the formation of dental calculus as an addi- tional manifestation of disturbed calcium-phosphate homeostasis. The combination of several components in saliva including calcium, phosphate, uric acid, and mag- nesium plays an important role in this process (9). Looking at the minerals that make up kidney stones, we see the same accumulation in the kidneys and teeth, sug- gesting similar mechanisms of stone formation (10). 161Archivio Italiano di Urologia e Andrologia 2018; 90, 3 Dental and renal calculi Table 2. Statistical comparisons of patient information. Table 3. Univariate and multivariate analyses of patient information. Kati_Stesura Seveso 04/10/18 11:58 Pagina 161 Archivio Italiano di Urologia e Andrologia 2018; 90, 3 B. Kati, E. Kalkan, E. Sabri Pelit, I. Yagmur, H. Çiftçi 162 Some researchers have found that nephrolithiasis is also accepted as a predisposing factor to pulpal calcification; however, some others could not find any correlation between the presence of pulp stones and kidney stones (11, 12). Some researchers have proposed that some of the minerals found in saliva cause the formation of stones in the salivary glands. Salivary sialoliths are pre- dominantly composed of crystals comprising calcium and phosphorous, with small amounts of magnesium, sodium, chloride, silicon, iron, and potassium (13). Rakesh N. et al. found that, when comparing sialoliths and nephroliths, they found a high degree of elemental similarity between them. Thus, they alleged that pre- scription drugs used for renal stones may be of some use in the conservative management of sialoliths (14). Shaimaa et al. evaluated idiopathic calcium renal stones and their relationship to dental calculi. They reported significant correlations between dental calculus accumu- lations and calcium renal stone formation, and they offered oral health preventive programs for those patients (15). Grases et al. found that salivary calcium concentrations of patients with hydroxyapatite calculi were significantly higher than that found in the saliva of healthy in their study. Therefore, their results were prac- tically identical to those found in the hydroxyapatite renal calculi (non-infective phosphate renal calculi) (16, 17). We assessed patients based on oral hygiene, renal stone history, teeth brushing habits, dental calculus recurrence, and comorbidities. The dental calculus per- centage was significantly higher in patients with kidney stones. This similarity can be seen because of the materi- als that make up the stone structure tend to accumulate in the body. This may be an indication that kidney stones can form in patients with a high dental calculus density. This condition, which is not related to the recur- rence frequency of the dental calculi, is also directly related to oral hygiene status. CONCLUSIONS There are similar features in terms of the formation of stones in the body and the minerals they contain. The height of dental calculi observed in the mouth is sig- nificant and stimulating in terms of kidney stones in patients. During physical examinations, the formation of a visible stone, such as a dental calculus, can be a pre- dictor of stones such as kidney stones, and this relation- ship should be further investigated. REFERENCES 1. Turesky SS. What is the role of dental calculus in the etiology and progression of periodontal disease? J Periodontol. 1970; 41:285-6. 2. Beiswanger BB, Segreto VA, Mallatt ME, Pfeiffer HJ. The preva- lence and incidence of dental calculus in adults. J Clin Dent. 1989; 1:55-8. 3. Jin Y, Yip HK. Supragingival calculus: formation and control. Crit Rev Oral Biol Med. 2002; 13:426-41. 4. Coe FL, Worcester EM, Evan AP. Idiopathic hypercalciuria and formation of calcium renal stones. Nat Rev Nephrol. 2016; 12:519-33. 5. Worcester EM, Coe FL. Clinical practice. Calcium kidney stones. N Engl J Med. 2010; 363:954-63. 6. Avogaro A, Fadini GP Mechanisms of ectopic calcification: impli- cations for diabetic vasculopathy. Cardiovasc Diagn Ther. 2015; 5:343-52. 7. Valenzuela A, Chung L. Calcinosis: pathophysiology and man- agement. Curr Opin Rheumatol. 2015; 27:542-8. 8. Aguilar-Ruiz J, Arrabal-Polo MA, Sierra M, Arrabal-Martin M. Application of mineralogical techniques in the study of human lithi- asis. Ultrastruct Pathol. 2012; 36:367-76. 9. Davidovich E, Davidovits M, Peretz B, et al. The correlation between dental calculus and disturbed mineral metabolism in paedi- atric patients with chronic kidney disease. Nephrol Dial Transplant. 2009; 24:2439-45. 10. Khan SR, Pearle MS, Robertson WG, et al. Kidney stones. Nat Rev Dis Primers. 2016; 2:16008. 11. Nayak M, Kumar J, Prasad LK. A radiographic correlation between systemic disorders and pulp stones. Indian J Dent Res. 2010; 21:369-73. 12. Tarim Ertas E, Inci M, Demirtas A, et al. A Radiographic Correlation between Renal and Pulp Stones West Indian Med J. 2014; 63:620. 13. Hiraide F, Nomura Y. The fine surface structure composition of salivary calculi. Laryngoscope 1980; 90:152. 14. Rakesh N, Bhoomareddy Kantharaj YD, Agarwal M, Agarwal K. Ultrastructural and elemental analysis of sialoliths and their comparison with nephroliths. J Investig Clin Dent. 2014; 5:32-7. 15- Shaimaa KY, Mohammed SA. Dental calculus in relation to idio- pathic calcium renal stone J Bagh Coll Dentistry. 2012; 24(sp. Issue 1):140-145. 16. Grases F, Santiago C, Simonet B. Sialolithiasis: mechanisim of calculi formation and etiologic factors. Clin Chim Acta. 2003; 334:131-6. 17. Grases F, Sohnel O, Villacampa AI, March JG. Phosphates pre- cipitating from artificial urine and fine structure of phosphate renal calculi. Clin Chim Acta. 1996; 244:45-67. Correspondence Bulent Kati, MD bulentkati@harran.edu.tr Eyyup Sabri Pelit, MD dreyyupsabri@hotmail.com Ismail Yagmur, MD dr_iyagmur@hotmail.com Halil Çiftçi, MD halilciftci63@hotmail.com Harran University, Favulty of Medicine Hospital, Urology, 63340 Sanliurfa, Turkey Ergin Kalkan, MD erginkalkan@hotmail.com Assistant Professor of Urology Cagri Dental Hospital, Dental Clinic, 23100, Elazig, Turkey Kati_Stesura Seveso 04/10/18 11:58 Pagina 162