Incidence, prevalence and clinical features of systemic sclerosis patients from a southern Brazilian city

Abstract

Background  Systemic sclerosis (SSc) is a chronic and heterogeneous disorder characterized by vascular, inflammatory, and fibrotic changes in the skin and internal organs. As epidemiological studies on SSc in Brazil are few, most reports are from international literature. This study aimed to determine the incidence, prevalence, clinical and laboratory characteristics, and therapeutic management of patients diagnosed with SSc in Cascavel, a southern Brazilian city.

Methods:  Cross-sectional study that collected data from all rheumatology services in the city (six private rheumatology clinics, a regional specialty center, a municipal specialty center, and an outpatient clinic at a university hospital) in 2020. After the epidemiological survey, eligible patients were invited to undergo investigation for possible orofacial manifestations.

Results:  We identified 57 patients who were treated for SSc in clinics, 30 of whom lived in Cascavel, Brazil. The estimated prevalence of SSc was 9 ± 0.03 cases/100,000 population, and the incidence in 2020 was 1.2 ± 0.004 cases/100,000 population. Most patients were female, and the mean age at diagnosis was 42.5 ± 17.22 years. The most frequently reported clinical feature is Raynaud's phenomenon, followed by skin thickening. Limited SSc was the SSc syndrome most frequently identified by physicians, and the antinuclear antibody test was positive in 86.66% of the patients. Six patients participated in the orofacial alteration investigation. Half of the patients had very low hyposalivation, and all had telangiectasias and periodontal disease.

Conclusions:  Clinical and epidemiological data from Cascavel, Brazil corroborate the findings of previous studies. Orofacial compromise was common in patients with SSc. Increased awareness among healthcare teams managing these patients is necessary to evaluate and manage orofacial problems.

Keywords
Systemic sclerosis; Incidence; Prevalence; Oral manifestations

Introduction

Systemic sclerosis (SSc) is a chronic and heterogeneous disorder that is usually characterized by vascular, inflammatory, and fibrotic changes in the skin and various internal organs [¹]. These changes result in the obliteration of microvessels and collagen accumulation, which leads to skin hardening and damage to the gastrointestinal tract, kidneys, lungs, heart, and oral cavity [²]. Its etiology remains unknown, but a multifactorial cause is suggested, possibly triggered by environmental factors in a genetically predisposed individual [³]. Its diagnosis is clinical, but laboratory tests support and help determine the prognosis. Its evolution can vary significantly in terms of severity, usually being slow and chronically disabling, but it can occur quickly, being progressive and fatal, owing to internal involvement [⁴].

Like other autoimmune diseases, SSc is difficult to diagnose, and since the 1980s, several criteria have been adopted to improve disease recognition. More recently, the American College of Rheumatology established new parameters that widened the spectrum of pathology, which now encompasses milder phenotypes to include significantly more patients [⁵].

SSc has been documented in all ethnicities and regions of the world. Studies conducted in several locations worldwide show highly variable incidence rates of the disease, ranging from relatively low rates, such as 1.1/1,000,000 in Norway, to high values, such as 32/1,000,000 in Ferrara, Italy [⁶, ⁷]. Epidemiological data on SSc are lacking in Latin America, and Brazil has only one study on its prevalence and incidence. This Brazilian study was conducted in Campo Grande, MS, reported an incidence rate of SSc of 11.9/1,000,000 inhabitants in 2014 and a prevalence rate of 105.6/1,000,000 inhabitants [⁸]. The most common epidemiological studies have approaches related to the onset of clinical manifestations or markers in patients [⁹, ¹⁰].

Few studies have reported changes in the oral cavity of patients with SSc. Those that exist have a high prevalence of at least one or more evident clinical change in the region [¹¹]. The clinical findings most described in the literature are xerostomia, limited mouth opening, mucosal ulcers and atrophy, temporomandibular disorders, tongue fibrosis, and increased incidence of caries and periodontal disease (PD). On radiographs, there is an enlarged periodontal ligament and mandibular resorption [¹²–¹⁴].

Given the limited epidemiological data available in Latin America concerning the prevalence, incidence, clinical presentation and occurrence of orofacial changes in SSc, we sought to evaluate these issues among SSc patients followed up in a southern Brazilian city.

Methods

Study design, study location, ethical issues and study population

This was a cross-sectional, descriptive, uncontrolled study conducted by reviewing medical records during 2020 of patients diagnosed with SS in Cascavel, Paraná, Brazil, a city in southern Brazil with 332,333 inhabitants in 2020 [¹⁵]. This study followed The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines and the Brazilian Guidelines on Research Involving Human Subjects (Res. CNS n. 196/96) with the approval of the Committee for Ethics in Research with Humans of Western Paraná State University (UNIOESTE) (No. 2,443,066) [¹⁶].

Data were collected from all rheumatology care facilities in the city (six private clinics and three specialized public centers) and, to be selected, should meet the 2013 classification criteria of the ACR/EULAR for SSc or should meet the 2001 criteria of LeRoy and Medsger for early SSc [⁵, ¹⁷]. Patients diagnosed with autoimmune diseases other than systemic sclerosis, including scleroderma (only cutaneous involvement, without systemic manifestations) and residents outside the municipality, were excluded. The denominator to calculate incidence and prevalence indexes was the population of the city estimated by Brazilian Institute of Geography and Statistics (IBGE) in 2020 (332,333 inhabitants). Therefore, incidence was calculated using the number of the patients who started SSc treatment at the year of 2020 (recently diagnosed) and prevalence was calculated adding the new cases to all those in treatment with home in Cascavel/PR.

A data collection instrument developed for this study was used, which included general information on the patient (age, sex, place of residence, and time of diagnosis), laboratory tests performed (anti-nuclear antibodies (ANAs)) as well as antibodies against extractable nuclear antigens (anti-ENA - anti-Scl70, anti-centromere, and anti-RNA polymerase III), clinical characteristics (Raynaud's phenomenon, skin thickening, interstitial lung disease, pulmonary arterial hypertension, gastric symptoms (nausea, vomiting, bloating, abdominal pain, diarrhea, and difficulty swallowing)) and other manifestations described by the physician, the clinical form of SSc (diffuse or limited), and the therapeutic management implemented (calcium channel antagonists, nifedipine, sildenafil, bosentan, methotrexate, cyclophosphamide, azathioprine, mycophenolate mofetil, rituximab, omeprazole, or another medication prescribed by the attending physician).

After data was collected from medical records, the patients under investigation were contacted by telephone and invited to participate in an assessment of oralfacial manifestations associated with SSc.

Medical history of oral manifestations

The patients were invited by telephone to visit the dental clinic of UNIOESTE for clinical investigation regarding possible orofacial manifestations associated with SSc. They were informed about the nature, potential risks, and benefits of participating in the study, and those who consented to participate signed the free and informed consent form. Those eligible were anyone of both sexes and all ages with a diagnosis and/or being treated for SSc in Cascavel/PR.

Anamnesis and physical examination of the patients were performed to evaluate the possible orofacial manifestations of SSc. Symptoms of oral and facial changes related to SSc documented in the literature, such as hyposalivation, telangiectasias, microstomia, the presence of caries, and periodontal disease, were considered. The same examiner performed all tests.

The first test is sialometry, which avoids stimulation of the salivary glands due to manipulation of the patient and/or stress/nervousness, which could interfere with salivary flow. Therefore, through mechanical stimulation (chewing) of a fragment of paraffin (Parafilm M®, Bemis Company, Neenah, Wisconsin, USA) that had been folded in half twice, all saliva produced over 5 min was expectorated in a graduated 50-mL Falcon tube (TPP, Switzerland). The salivary flow rate was classified as the secretion rate per minute, and foam was excluded. Values lower than 0.7 mL/min were considered deficient salivary flow, 0.7–1 mL/min low, and > 1 mL/min regular [¹⁸].

A digital caliper (model 727, Starrett, São Paulo, Brazil) was used to verify maximum mouth opening. In the first analysis, with the patient seated, the head was oriented with the Frankfurt plane parallel to the floor, and the mouth was opened as far as possible. Three measurements were taken from the edge of the right upper incisor to the edge of the right lower incisor, and the average was taken. The standard distance defined for maximum mouth opening was 45 mm, as some authors emphasize that it can vary between 42 and 60 mm for adults [¹⁹, ²⁰]. Microstomia was possible if the opening value was smaller than 45 mm.

In the intraoral investigation, the presence of dental caries was verified through the decayed, missing, filled (DMF) index, which is based on calculations for 32 permanent teeth. The presence of dental plaque and calculus was analyzed via the visible plaque index [²¹]. Teeth were scored on the basis of (0) the absence or [¹] presence of visible plaque (visible plaque score) and dental calculus (dental calculus score). Periodontal disease was measured via a periodogram, which assessed bleeding on probing, tooth mobility, furcation lesions, and periodontal pockets. All measurements were taken via a North Carolina No. 15 single-point periodontal probe (Hu-Friedy Mfg. Co., Chicago, USA). The periodontal diagnosis classified the patients into periodontal health, gingivitis, or periodontitis, according to the criteria established in the most recent classification of periodontal diseases and conditions [²²].

Statistical analysis

The data was processed in Microsoft Office Excel® spreadsheets, and was exported and analyzed using XLSTAT software, version 345. Descriptive analysis was performed by calculating the mean ± standard deviation of continuous variables and the frequency of categorical variables. CI 95% for single measure was calculated to incidence and prevalence index. The parameters age, sex, collection site, time to diagnosis, ANA test result, positive ANA test titer, positive ANA test pattern, anti-Scl70 autoantibodies, anti-centromere autoantibodies, anti-RNA polymerase III autoantibodies, disease form, and clinical manifestations presented by the patients were statistically evaluated using the Chi-squared goodness of fit test, applying an alpha of 0.05. The data were tabulated in Microsoft Office Excel® spreadsheets, and the analyses were performed using.

Results

Clinical and epidemiological data

A total of 57 individuals diagnosed with and/or under treatment for SSc were found in Cascavel/PR during the collection period, of which 30 were residents in the city. Thus, these patients were used to calculate the prevalence and incidence of SSc in Cascavel/PR. On the basis of the population of the city estimated by the Brazilian Institute of Geography and Statistics (IBGE) in 2020 (332,333 inhabitants), the prevalence was 9.03 ± 0.03 (95% CI) cases per 100,000 inhabitants. Among the 30 patients, 4 were new cases, resulting in an incidence of 1.2 ± 0.004 (95% CI) cases per 100,000 inhabitants per year.

The epidemiological data of these thirty patients revealed that the mean age was 42.5 ± 17.22 years, ranging from 20 to 89 years, with a predominance of 40–49 years in 10 (33.3%) patients (p = 0.0019). Twenty-seven (90%) were female, and only 3 (10%) were male (p < 0.0001). Regarding the clinical form, 18 (60%) people had limited SSc, 10 (33.33%) had diffuse SSc, and 2 (6.67%) had no data in the medical records specifying the SSc form (p = 0.130) (Table 1). Furthermore, 16 (53.33%) patients arrived at the health system (public or private) without being diagnosed with the disease. For these patients, the time elapsed between the first complaint and diagnosis of the disease was less than six months in 37.5% [⁶], 6–24 months in 25% [⁴] of them, and longer than 24 months in 12. In 5% [²] and 25% [⁴] of the cases, there was insufficient information to allow diagnostic delay tabulation. Therefore, the mean time to diagnosis was 21.41 ± 34.17 months.

Table 1
Epidemiological and clinical characteristics of SSc patients from Cascavel/PR, Brazil, in 2020

Characteristics	n (30) 100%
Gender
Male	27 (90.0%)
Female	3 (10.0%)
Mean age	42.5 ± 17.22
Age group
20–29	1 (3.3%)
30–39	5 (16.7%)
40–49	10 (33.3%)
50–59	8 (26.7%)
60–69	3 (10%)
70–79	0 (0%)
80–89	0 (0%)
Not reported	3 (10.0%)
Type of clinic
Public	16 (53.3%)
Private	14 (46.7%)
Form
Limited	18 (60.0%)
Diffuse	10 (33.3%)
Not reported	2 (6.7%)
Clinical manifestations
Raynaud's phenomenon	26 (86.7%)
Skin thickening	21 (70.0%)
Interstitial lung disease	10 (33.3%)
Pulmonary arterial hypertension	5 (16.7%)
Gastric symptomsOral manifestations	16 (53.3%)
Drug therapy
Calcium channel antagonist	8 (26.7%)
Sildenafil	29 (96.7%)
Bosentan	8 (26.7%)
Methotrexate	0 (0%)
Cyclophosphamide	18 (60.0%)
Azathioprine	6 (20.0%)
Mycophenolate mofetil	4 (13.3%)
Rituximab	0 (0%)
Omeprazole	0 (0%)
	21 (70.0%)

• ^*
  NE – not evaluated

The evaluation of the clinical characteristics of SSc most frequently reported by physicians revealed that Raynaud's phenomenon and skin thickening were present in 86.67% [²⁵] (p < 0.0001) and 70% [²⁰] (p = 0.028) of individuals with the disease, respectively. Professionals recognized alterations in the oral cavity, such as micro-stomia and xerostomia, in 26.67% [⁸] of the patients. Systemic involvement was detected in the patients, and the main manifestations observed were gastric symptoms in 53.3% (16 patients) and interstitial lung disease (33.3% − 10 patients).

With respect to the laboratory tests requested by the physicians, the anti-Scl70 and anti-centromere tests had nonreactive results in 46.66% [¹⁴] and 53.33% [¹⁶] of the patients, respectively. In 63.33% [¹⁸] of the cases, anti-RNA polymerase III was not available in the patient's medical records, and of those who had this information, only 6.66% [²] reacted positively. ANA was positive in 86.66% [²⁵] of the cases, and in 13.34% [⁴] of the cases, the medical records indicated that the test had been performed but did not report the results. Therefore, 100% of the patients who had ANA data tested positive. These data are illustrated in Table 2. The titers of ANA achieved by 50% [¹⁵] of the patients were in the high-titer range (≥ 1/640). Considering only those with ANA results in the medical records, 57% of the patients had ANA results with high titers.

Table 2
ANA, anti-Scl70, ACA, and anti-RNA polymerase III results of SSc patients from Cascavel/PR, Brazil, in 2020

Laboratorial test	n (30) 100%
ANA
Positive	26 (86.7%)
Negative	0 (0%)
NR	4 (13.3%)
Anti-Scl70
Positive	9 (30.0%)
Negative	14 (46.7%)
NR	7 (23.3%)
ACA
Positive	6 (20.0%)
Negative	16 (53.3%)
NR	8 (26.7%)
Anti-RNA polymerase III
Positive	2 (6.7%)
Negative	8 (26.7%)
NR	19 (63.3%)

• ^*
  NR – not reported; ANA – antinuclear antibodies; ACA – anti-centromere antibodies

The patterns of ANAs in greater numbers were nuclear homogeneous and centromeric, with 23.3% [⁷] each. A nuclear fine speckled was present in 20% [⁶] of the cases. However, nuclear large speckled, nuclear dense fine speckled, nucleolar, and mitotic apparatuses were also observed.

The most commonly used therapies in patients diagnosed with SSc were calcium channel antagonists (96.66%, 29), methotrexate (60%, 18), and omeprazole (70%, 21). Medications such as sildenafil, cyclophosphamide, and azathioprine were also prescribed to control the symptoms of the disease, but less often.

Orofacial manifestations– a pilot study

Of all the patients selected for the study, six agreed to visit the dental clinic to evaluate any orofacial changes due to SSc. Due to the small number of patients, this part of the results in the manuscript should be addressed as a pilot study, with limitations in its conclusions. Their ages ranged from 35 to 56 years; 83.33% [⁵] were women, and 16.66% [¹] were men. The form of SSc present in this group was 50% diffuse and 50% limited.

Sialometric examination revealed that 50% [³] of the patients were classified as deficient, 33.33% [²] as low, and 16.66% [¹] as regular. Considering the expected value for a maximum oral opening of 45 mm, we found that of these six patients, 50% [³] had values greater than 45 mm, and 50% [³] had values less than 45 mm. For telangiectasias, 100% [⁶] had changes in the face: 66.66% [⁴] in the vermilion of the lip, 33.33% [²] in the tongue, and 33.33% [²] in the intraoral mucosa.

The mean DMF index was 21.16. The mean indices of visible plaque and dental calculus were 0.37 and 0.23, respectively. The periodogram revealed periodontal disease in 100% [⁶] of the patients. The clinical orofacial characteristics of the patients are listed in Table 3.

Table 3
Oral manifestations of SSc patients from Cascavel/PR, Brazil, in 2020

Orofacial findings	n (6) 100%
Sialometry
Deficient	3 (50.0%)
Low	2 (33.3%)
Regular	1 (16.7%)
Maximum oral opening
>45 mm	3 (50.0%)
<45 mm	3 (50.0%)
Telangiectasias
Changes in face	6 (100.0%)
Periodontal diseases
Presence	6 (100.0%)

Discussion

This study determined the prevalence (9.03 ± 0.03 (CI 95%) cases per 100,000 inhabitants) and incidence (1.2 ± 0.004 (95% CI) cases per 100,000 inhabitants per year) of SSc in Cascavel/PR, a city in southern Brazil. The most patients were women (90%), with a mean age of 42.5 ± 17.22 years and predominant clinical form was the limited SSc. Raynaud's phenomenon was the most prevalent manifestation (86.7%) and 100% of the patients that performed ANA test, were positive.

This study is the first to evaluate the prevalence, incidence, clinical and therapeutic characteristics and orofacial manifestations of SSc in a southern city in Brazil. The patients were a heterogeneous group in different stages of clinical manifestations and various places on the spectrum of SSc.

In Brazil, there are practically no studies on the incidence or prevalence of SSc, and compared with our study, one study reported a higher value. This analysis in Campo Grande, Mato Grosso do Sul, revealed an incidence of 1.19/100,000 inhabitants in 2014 and a prevalence of 10.56/100,000 [⁸]. A systematic review of 50 articles published between 2000 and 2016 reported that the incidence rates of SSc in Europe and North America were 0.6–2.3 and 1.4–5.6 per 100,000 inhabitants/year, respectively. The prevalence rates were 7.2–33.9 and 13.5–44.3 per 100,000 inhabitants, respectively [²⁴]. These values are consistent with our findings (incidence of 1.2/100,000 inhabitants/year and prevalence of 9/100,000 inhabitants) but are more similar to the European values. For example, the incidence in the county of Scania, located in Sweden, was 1.4–1.9/100,000/individual in 2010 [²⁵]. In northwest Greece in 2002, the rate was 1.1/100,000 inhabitants [⁷]. North America has a high prevalence, reaching a value of 44.3/100,000 in Quebec, Canada, in 2003 [²⁶], as do some places in Europe, such as the Netherlands, with values of 8.9/100,000 inhabitants in 2007 [²⁷]. Possible disparities in the incidence and prevalence rates of SS between different regions may be due to methodological differences in the definition of the criteria used to diagnose the disease and in the verification of existing cases, in addition to regional differences in genetic susceptibilities and environmental factors.

In our study, as in other regions of Brazil and the world, the disease was predominant in females [¹, ⁶, ²³–²⁶]. Patients living in Cascavel had a ratio of 9:1 (women: men), whereas in São Paulo, this ratio was 7.7:1 [²⁷], and in the city of Campo Grande, this value was 28.7:1 [⁸]. In Europe, the ratio was 15.6:4.2 [²³], and in South America, more precisely, in Argentina, the ratio was 17:1 [²⁶]. The mean age at diagnosis of our patients (42.5) was similar to that reported in other studies, where it was the fourth to fifth decade of life [²⁴, ²⁷–³¹].

In this study, the limited clinical form showed a predominance over the diffuse clinical form, as in other studies in our country. Two other studies in southern Brazil reported that limited SSc was present in 62.1% and 65,62% of cases [²⁵], and a third study in Brazil reported a value of 56,4% [¹, ²⁷]. In other parts of the world, such as the northeast region of England, a ratio of 4.7:1 (limited: diffuse) was found, which is higher than that in Cascavel (1.8:1) [²⁹]. In turn, a national study in Germany revealed a frequency (limited: diffuse 1.5:1) that was more similar to that in western Paraná [²⁴].

The most frequent symptom experienced by patients from Cascavel was Raynaud's phenomenon, which was present in 86.67% of them. This situation is similar to that of most studies, which show that Raynaud's phenomenon is the most common manifestation among patients, such as another Brazilian sample (84%) [³²], a Canadian sample (85%) [³³], and a European sample (95%) [³⁴]. On the other hand, gastric symptoms are very common in SSc patients. A study in Germany revealed that 98.9% of patients developed gastrointestinal manifestations when followed for 1 year [³⁵]. Data from patients in the UK revealed a similar result, with a 90% frequency of gastric symptoms in a national survey [³⁶]. In this study, only 53.3% of the patients presented these manifestations. This could be caused by underreporting in medical reports, since this study used secondary information or because it was a cross-sectional study that did not follow patients.

We detected ANA positivity in 86.66% of the cases, with predominant nuclear homogeneous and centro-mere patterns and titers higher than 1/640. This result is in line with another local study in southern Brazil, which reported ANA positivity in 92.94% of the evaluated individuals but did not provide data about the patterns or titers of the tests [²⁵]. In the central-western region of the country, the ANA test was positive in 94.4% of the cases, with a predominance of nuclear fine speckled and centromere patterns [⁸]. In other studies worldwide, ANA also had high positive rates [²⁴, ²⁸, ³⁷, ³⁸], but the most prevalent pattern was nuclear fine speckled [³⁹, ⁴⁰]. Although the ANA test is not one of the diagnostic criteria for SSc, specific autoantibodies are a screening method for detecting these patients, given the ease of indirect immunofluorescence for their detection [⁵, ⁴¹].

The presence of anti-centromere antibodies in patients who had such results in their medical records (27.3%) in this study is similar to that reported in the literature. Anti-centromere antibodies occur in 20% to 40% of earlier patients with SSc [³⁸] and are more common in white patients and those older than 50 years. Although closely related to SSc, anti-centromere antibodies are not exclusive to this disease and may rarely be found in patients with primary biliary cirrhosis, Sjögren's syndrome, or systemic lupus erythematosus [⁴², ⁴³].

According to Andrade and Leser (2004), the sensitivity of anti-Scl70 antibodies in SSc patients is variable and is found in 26% to 76% of patients, depending on the population and the method used [⁴⁴]. Among our patients who were diagnosed with SSc and resided in Cascavel, 30%, which was slightly higher than the 17.8% reported in another study conducted in southern Brazil [¹]. The diffuse form is more closely linked to the presence of anti-Scl70 antibodies, as observed in the present study; however, the prevalence of the diffuse form (33.3%) was higher than that reported in another study (10%) [⁴⁵].

In our study, the most commonly prescribed medication was a calcium channel antagonist (96.66%) because of its effectiveness in controlling Raynaud's phenomenon. Rituximab and mycophenolate mofetil were not indicated for any patient, which may have been due to the high prescription rate of methotrexate (60%) and the frequent positive response to it since it is the first-line drug preferred by physicians, and if it is not successful, the former two are prescribed [⁴⁷]. Moreover, rituximab and mycophenolate mofetil are high-cost medications that are currently not provided by the Brazilian National Health Care System.

Regarding oral and facial manifestations, the small sample size of our study was because the recruitment of patients was performed in 2021, and Covid-19 interfered directly with the outcome, as patients with autoimmune diseases were the most affected by SARS-CoV infection. So, the results of orofacial manifestations should be considered as a pilot study due to small number of patients and considered with caution. Our study highlights the importance of orofacial manifestations and their daily impact, which is likely underestimated.

We identified the presence of telangiectasias in all the patients analyzed at this stage. The findings of other researchers suggest that this manifestation may be characteristic of patients with SSc. For example, a French study reported that 70% of its sample had telangiectasia [⁴⁶].

With respect to hyposalivation, most studies use only the subjective symptom xerostomia without evaluating salivary volume [¹⁴, ⁴⁶, ⁴⁷]. In this study, salivary production was evaluated, and the results were mainly in the deficient and low categories. Hyposalivation is a common adverse effect of some medications, such as the calcium channel antagonists sildenafil and omeprazole. In addition to these drugs, some patients take antidepressants and anxiolytics to treat SSc, which can also affect salivary production [⁴⁸]. In addition, the hyposalivation may also be secondary to salivary gland fibrosis occurring in SSc [⁴⁹]. Furthermore, hyposalivation can occur due to the presence of Sjögren's syndrome, one of the most common autoimmune diseases that often overlaps with SSc [⁵⁰]. Hyposalivation caused by SSc can have several impacts on mouth health, such as dysphagia, increased susceptibility to oral infections, ulcerations, mucosal inflammation, dental caries, periodontitis, and atrophic changes in the oral mucosa, leading to social and emotional impacts and significantly affecting nutrition and quality of life [¹⁴, ⁴⁸, ⁵¹].

Our patients have difficulty maximizing their mouth opening, which is in accordance with other findings worldwide [¹², ⁴⁶, ⁵²]. This shortcoming is due to the chronic accumulation of collagen in SSc, leading to skin thickening [¹¹, ⁵³]. Limited mouth opening in SSc patients can hinder access to and prevent proper care of the teeth, leading to an increased incidence of dental caries and periodontal disease. Additionally, hyposalivation contribute to high levels of periodontitis and DMF index in SSc patients, as founded in this study in Cascavel/ PR (100% and 21.16, respectively), similar to the index in China (76% and 21.1). Another study in the Romania showed a level of periodontitis of 88,68% [⁵⁴, ⁵⁵]. Therefore, it is advisable that those diagnosed with pathology visit the dentist more routinely.

One limitation of the study was that only patients with SSc were considered, and overlapping diseases were excluded. Furthermore, epidemiological studies face difficulties in establishing the point at which SSc begins, i.e., the delay between the onset of symptoms and diagnosis. In addition, insufficient information in medical records affects the quality of clinical data. Another problem was the low participation of SSc patients in orofacial investigations. Lastly, the health coverage in Cascavel/ PR should considered in data obtained. The healthcare system in Brazil is universal, where the entire population has the right to access it. Furthermore, people with better financial means purchase private health insurance plans. The local health system in the city is well organized and 100% of the population has access to primary health care by public or pay acess and patients with symptoms of autoimmune diseases are forwarded to a public center for health specialties, which possess rheumatologists to finalize the diagnostics. However, physician from primary care could did not detected properly autoimmune symptoms, causing an underestimation of the disease.

Conclusions

This study is the first to gather epidemiological data on SSc in southern Brazil and adds data to the incipient literature on this disease in Latin America. The prevalence and incidence of SSc detected in Cascavel/PR were similar to those reported in other Brazilian studies and those reported in Europe, improving the description of data on SSc worldwide. The patients presented typical oral characteristics of SSc, such as hyposalivation and difficulty in maximizing their degree of mouth opening. Periodontitis and high DMF índices are frequent in SSc patients. Increased awareness of oral health issues and the need of oral and dental care for these patients are warranted.

• Funding
  The authors declare that this study received no financial support.
• Declarations
  Ethics approval and consent to participate
  This study was approved by the Ethics Committee of Western Paraná State University/Unioeste (No. 2,443,066). All the participants signed an informed consent form.
• Consent for publication
  Not applicable.
• Publisher's note
  Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Acknowledgements

The authors thank all clinics that allowed access to patients’ medical records.

Data availability

The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.

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Edited by

• Responsible editor:
  Ana Karla Guedes de Melo

Publication Dates

• Publication in this collection
  17 Aug 2026
• Date of issue
  2026

History

• Received
  30 Sept 2024
• Accepted
  02 Feb 2026
• Published
  21 Feb 2026