The decline in the prevalence of oral diseases has been observed in developed countries, but the increasing prevalence of oral diseases was reported on a global level (1, 2). The factors that contribute to the incidence of oral diseases are of socioeconomic character, and include poverty, illiteracy, lack of oral health education, and lack of access to oral health services (3). The issues concerning lack of oral health education and inappropriate oral health services are greatly determined by weak or non-existent national oral health programs, and poorly managed public dental health facilities (4, 5).
Although the global burden of oral diseases suggests that health planning should be put in broader perspective, the caries prevalence studies in many countries show uneven distribution among the population. This makes more studies oriented towards specific regions or subpopulations preferable over large scale national surveys (1, 6). Other factors that make this particular study highly justifiable include demographic changes, the setbacks due to the war in the 1990-ies, the economic transition through which Croatia recently went, and the lack of a national program for oral health promotion. The conducted research included Croatian region which was probably most affected by the above mentioned events.
According to the latest census from 2011, 15388 inhabitants live in Knin and its surroundings. The geographic position of Knin has made it an important strategic point throughout history. It is situated at the intersection of Bosnia and two Croatian regions: Lika and Dalmatia. Due to its position, it has been exposed to war events many times. After the recent war (1991-1995), the population of Knin has changed considerably. Many refugees from Bosnia and Herzegovina (about 7000 of them) inhabit Knin and the surrounding area, while the majority of Serbs who had lived in Knin until 1995, fled to Serbia and Serbian ethnic parts of Bosnia and Herzegovina. About 2000 people from the eastern part of Croatia, which was also greatly affected by the war - Slavonia, also populated the area after 1995 (7).
The demographic changes, together with other consequences of the war and economic transition, affected many aspects of life, including public health issues. Since the epidemiological study on oral status of Knin population has not been conducted so far, the main purpose of this cross sectional study was to obtain relevant data about the oral status of the population of Knin and its surroundings according to the WHO criteria, and to compare the oral status of domicile and immigrant population. Furthermore, the aim was to compare the results with the results from other parts of Croatia, and other European countries, as well as with the WHO “goals for 2020”.
More studies such as this, oriented towards specific regions, are needed and their results could be used in planning and organizing oral health care considering specificities of the region in health planning and making programs to meet the expected WHO “health for all” goals.
Subjects and Methods
The data were collected in the Community Health Center Knin during March and April of 2010. The study included 414 (184 male and 230 male) subjects aged between 18 and 65 years. Each subject was informed on the nature of the study and gave informed consent for the examination.
The examination was carried out under standardized conditions using dental mirror and CPI probe under dental light, by one examiner who had been calibrated as described (5). The applied force on probing was equivalent to the weight of 25g (0.025 kg x 9.81 m/s2).
The form was custom designed according to the assessment form recommended by the World Health Organization (8). For each subject sex, age, education level, residence (urban vs. suburban-rural) and origin was recorded (domicile or immigrant). According to the education level, the subjects were divided into 4 groups: elementary, high school, baccalaureate, university level. The individuals residing in Knin from the times before the war (1991-1995) were considered domicile population, whereas those inhabiting it from any time between 1995 and today were considered immigrants.
For diagnosis and coding, the WHO (8) criteria were employed. Dental status and periodontal health status for all sextants (17, 14, 13-27, 37-34, 33-43 and 44-47) were recorded, and DMFT and CPI indices were determined. The scores of the CPI index were as follows: score 0- healthy periodontium, score 1- gingival bleedings, score 2: calculus and bleeding, score 3: shallow periodontal pockets (4 to 5 millimeters), and score 4: deep periodontal pockets (6 millimeters or more).
Other variables recorded in assessing oral status were: pathological lesions on oral mucosa, opacities and hypoplasia (on teeth 14,13,12,11,21,22,23,24,36,46), TMJ symptoms and/or signs and prosthodontic status. Apart from the mentioned variables, the following was estimated: the need for dental treatment, the presence of pain, infection or urgent conditions.
The data were analyzed using SPSS program package (SPSS v. 16.0, SPSS Inc., Chicago, IL) using descriptive analysis, chi square test (to determine significant differences between the categorical variables), Mann-Whitney test and Kruskal-Wallis test (to determine differences between age groups and genders). Normality of data was tested using Kolmogorov-Smirnov test. The level of significance was 95% (p<0.05)
The study included 414 subjects out of which 184 (44.4%) were males and 230 (55.6%) females. Domicile population accounted for 52.7% and immigrants 47.3%. The average age was 39.14 years (SD=13.12), and t-test showed that there was no significant difference in age distribution between the domicile (M=40.23, SD=13.36) and immigrant (M=37.93, SD=12.78) group (t=1.772, df=408, p=0.078). There were no statistically significant differences between domicile and immigrant group according to the gender and level of education distribution (χ˛=0.663, df=1, p=0.430 and χ˛=3.589, df=3, p=0.309, respectively). The percentage of subjects with higher education level was higher among the domicile group, and significantly more immigrants populated urban areas (χ˛=13.470, df=2, p=0.001).
Of the systemic diseases, cardiovascular diseases were the most prevalent (12.7%), followed by allergies (2.9%) and diabetes mellitus (2.0%) while 0.2% of the subjects had one of the listed infective diseases (HIV, TBC, Hepatitis). Smokers accounted for 40.5% of all subjects.
Extraoral examination showed that 88.5% of the subjects did not exhibit any pathological changes of oral mucosa, 7.8% exhibited UREF (ulceration, redness, erosion, and fissure) on the head, neck or limbs, 3.2% had UREF on the nose, cheeks or chin, while 0.2% was on the labial comissurae.
TMJ examination revealed a rather small percentage of subjects with TMJ symptoms (3.9%), signs (7.6%) or sounds (8.6%). Only 1.5% of subjects exhibited sensitivity on palpation, and reduced mouth opening was observed in 0.2%. The prevalence of TMJ related phenomena and the prevalence of extraoral pathological findings was very low, hence the comparison between domicile and immigrant group was not made.
Oral examination showed that almost 95% of the subjects had healthy mucosa. Candidiasis was found in 2.4%, ulcerations in 1.2%, leukoplakia in 0.7%, lichen ruber planus in 0.2%. Most of the changes were located on labial borders (63.2%), followed by those on the palate (soft/hard) (15.8%), alveolar process/ gingiva (8.8%), tongue (7.0%), while the frequency was the lowest on labial anguli, sulci and buccal mucosa (1.8% each).
Opacity/ hypoplastic changes
The percentage of observed mineralization defects is shown in Table 1. The most frequent change was hypoplasia. There was no statistically significant difference between the domicile and immigrant group (popacity=0.646; phypoplasia=0.605). Also, there were no significant differences noted between genders in either group (domicile: p b.o.=0.438; popacity=0.738; phypoplasia=0.873; immigrant: p b.o.=0.672; popacity=0.743; phypoplasia=0.882).
The average number of teeth not exhibiting any hypomineralization change (b.o.) was significantly higher in the youngest group in both domicile (χ˛=35.652, df=4, p<0.001) and immigrant group (χ˛=23.338, df=4, p<0.001).
Periodontal status and CPI
Periodontal status was recorded for all sextants and CPI was determined as suggested by the WHO (score 0, 1, 2, 3 and 4 for healthy periodontium, gingival bleeding, calculus and bleeding, pockets 4-5 mm and pockets ≥ 6 mm, respectively).
Periodontal status of the examined population is shown in Table 2. The subjects had on average two healthy sextants, one sextant with bleeding, one with calculus (supra- and/or subgingival), and one sextant excluded. Significant differences between smokers and nonsmokers were found only in the average number of healthy teeth which was higher in nonsmokers (p<0.001), and the number of excluded sextants which was higher in smokers (p=0.005). According to the education level, it was found that the groups with higher education level (Baccalaureate and University) had significantly more healthy teeth (p<0.001), and the highest frequency of excluded sextants was among the least educated (p<0.001).
HP- healthy periodontium; BP- bleeding.
CPI score is shown in Table 3. The differences between the age groups in CPI scores were statistically significant (ANOVA, F=5.594, p=0.001), while the difference between genders was not significant (ANOVA, F=3.353, p=0.068), except for CPI score 0 which was significantly more frequent in females (F=5.371, p=0.021). The difference in CPI score between domestic and immigrant population was not significant (F=0.236, p= 0.628).
Dental status and DMFT
Dental status was recorded and the results were presented in Table 4. Figures 1 and 2 show the dental status according to the age and the level of education. An individual had 1.7 caries, 6.2 fillings, and 9.57 teeth extracted on average. Carious teeth were not recorded in 49% of the subjects, 15.2% had one carious tooth, 10.6% two, 7.2% three, and 17.9% had more than three carious teeth (4-12 teeth). In 14% of the subjects there were no fillings recorded, while in the rest of them the number of fillings ranged from one to 21 per individual. Only 16.9% of the subjects had 0 teeth extracted, and 3.9% were completely edentulous. The percentage of edentulous individuals was significantly higher among those older than 45 years (Chi-square, χ˛=24.518, df=4, p=0.001, C=0.237). The percentage of individuals with functional dentition (i.e. 21-32 teeth) was considerably higher among subjects younger than 44 (Chi-square, χ˛=141.250, df=4, p<0.001, C=0.506). 33.1% of the subjects had less than 21 teeth. The extractions were mostly due to caries. In 93.7% of the subjects there were no extractions due to other reasons. Dental fissure sealants were found in only 1.5% of the subjects. The great majority of the subjects (84.8%) had neither abutments, nor crowns nor implants. Nevertheless, their average number was significantly higher in domicile population (p<0.05). Unerupted teeth were recorded in 14.8% of the subjects, and amounted to 1-4 teeth.
From the collected data, DMFT index was calculated and its average value equaled 17.5. DMFT index equaled less than three in only 5 of 414 subjects (1.2%). The highest DMFT observed equaled 32 in 4.8%. The average DMFT among the 30% of the individuals with the worst DMFT index i.e. SIC index, counted 26.44 (SD=3.34, min=22, max=32).
DMFT and SIC indices were not significantly different between the domicile and immigrant group (p=0.438), males and females (p=0.288), and urban and suburban/rural population (p=0.091). In both genders the average DMFT was 17. The difference was significant regarding the level of education (p<0.001) and age (p<0.001) – in subjects with baccalaureate and university diploma, and in younger age groups, DMFT was significantly lower (p<0.001). Also, DMFT was significantly higher in smokers (p=0.001).
In the immigrant group, significantly more caries (p=0.006) and fillings (p<0.001) were recorded in the youngest group (<18y) compared to the other age groups, while the average number of extractions was significantly higher in subjects aged >41 years (p<0.001) than in others.
In domicile group, a significantly higher caries frequency was recorded in subjects aged between 19-30 years (p<0.001), fillings in those <18 years (p<0.001), while extractions were the most frequent in >41 years (p<0.001).
Regarding the level of education, in the group with high school and university diploma, the average number of teeth with fillings was significantly higher r(pdomicile<0.001 pimmigrants=0.038), and the number of extracted teeth significantly lower (pdomicile and immigrant<0.001) compared to the group with elementary education. In domicile population, the average number of abutments, crowns and implants was significantly higher in high school and university educational level, than in the subjects with elementary educational level (p=0.031).
As far as prosthodontic status is concerned, in 2/3 of the subjects the denture was not present in the upper jaw, and in ľ it was not recorded in the lower jaw.
Of the dentures recorded, partial dentures in both jaws were present in 13% of the subjects, total upper dentures in 10%, while fixed dentures were recorded in 12% of the subjects, and mostly in the upper jaw. The need for prosthodontic treatment was noted in 37% and 48% of upper and lower jaws respectively. The most frequent prosthodontic need included bridges in both jaws.
The dental treatment, apart from prosthodontics, was required in 73.4% of the subjects, and the most needed one was restoration with fillings (in 71.7% of the subjects).
Discussion and Conclusion
Oral health status is determined by numerous factors on individual and community level. Besides the socio-demographic and individual factors (oral health behaviors), the importance of oral health systems organization and oral health programs orientation in achieving satisfactory oral health, has been pointed out in recent reports (1, 2, 9, 10). Moreover, the lack of proper community oral health programs has been recognized as the major determinant in inadequate oral health care and high oral diseases prevalence, generating the growing "burden or oral diseases“. Furthermore, among different countries and regions, different patterns of oral disease have been reported, which reflects distinct risk profiles and brings about the need to organize oral health services that meet the needs of the local population as suggested by WHO global strategies (4, 11, 12). The lack of national strategy in oral health policy in Croatia calls for urgent epidemiological screening, and regionally oriented studies in accordance with global aims.
Caries and periodontal diseases are the two most common oral pathologies, and the indices describing the prevalence of these two diseases are often used to roughly describe the oral health status of a population. Significant Caries Index (SiC index) is a newer index introduced to identify the individuals or groups exhibiting the highest DMFT values (13). Focusing on individuals having the highest disease prevalence is a prerequisite for more specific and effective measures. However, the first goal to be achieved is DMFT less than 3, and SiC index 3 in 1/3 of the population with the highest DMFT is a further step. When SiC on the national level is achieved, the measures should be oriented towards regions, towns and even schools.
The average value of DMFT index for the population examined (18-65 years) was 17.3, which is very high. On average, each person had almost 10 missing teeth, which reflects a certain behavioral pattern where tooth extraction is preferred over treatment. The average SIC index is also very high, 26.44. In more educated population DMFT was significantly lower, as expected, since the education is firmly recognized as the socio-demographic factor influencing oral disease status, namely caries prevalence. Similarly, the DMFT index was significantly higher in smokers, as expected (p=0.001). The high values of DMFT and SIC indices could be explained by unfavorable war events in the 1990ies that, not only led to mass migrations, but seriously affected the population economically. Furthermore, the process of economic transition began in the early 1990s and is still going on. It has previously been found that the highest DMFT values are found in transition countries (14). Our study also showed that the DMFT and SIC values were high, irrespective of the population origin. The reason lies probably in the fact that most of the population come from the parts of Bosnia that are geographically similar to the continental part of Dalmatia. Furthermore, more than 15 years passed since the immigrants settled in Knin, and it could be expected that during this time some differences in mentality and habits faded. Together with the similarly low health awareness and the absence of preventive programs, this leads to extremely high DMFT and SIC indices.
The reported post-war DMFT values for central Dalmatia (costal and inner parts) were 21.73 and 23.73 for the ages 35-44 and 65-74, respectively (15). This is in concordance with our results. Although we examined the adult population, we here refer to the results of DMFT index among 12-year in order to make easy comparisons between countries. The tendency of increasing DMFT index among 12-year olds in Croatia has been reported and it increased from 2.6 in 1991 to 3.5 in 1999. Moreover, in 2008, Jurić et al. reported DMFT of 6.67, and SIC 10.89 among 12-year-olds in another Croatian area also seriously affected by the war (Petrinja) (16, 17). This situation calls for urgent preventive measures planning and implementation, especially in certain parts of the country.
In 2013 Croatia became a member of the EU, and when comparing DMFT values with other European countries the results are alerting. For example, the most recent DMFT scores in the nearest EU countries among 12-year olds are according to the Malmö University Oral Health database (18) as follows: Slovenia 1.8 (1998), Italy 1.1 (2004), Austria 1.0 (2002). The score is very similar to the scores in former socialist countries that either underwent or are still going through economic transition, irrespective of their membership in the EU: Albania 3.1 (2005), Bosnia and Herzegovina 4.2 (2004), Bulgaria 3.1 (2008), Hungary 3.3 (2001), Latvia 3.4 (2004), Lithuania 3.7 (2005), Macedonia 3 (1999), Poland 3.2 (2003), Serbia 2.9-7.8 (1994), Slovakia 4.3 (1998). It was well documented in previous epidemiology studies that DMFT index presents a relevant indicator of oral health and socio-economic status, which is also confirmed by our study (14). In industrialized western countries the caries prevalence decreased and is concentrated in 20% of the population (19). On the contrary, in the population we studied, caries was present in 49% of the subjects, and when taking into consideration that every individual had on average almost 10 teeth extracted, the prevalence of caries is even higher when compared to the developed countries. It is also very distressing that of the total examined population, only 66.9% had functional dentitions (21-32 teeth), which makes the WHO goal for the year 2000 hardly achievable in the near future (20).
The results of this study show the increasing CPI with age and in smokers. These findings are consistent with the reported increasing prevalence and progression of periodontal disease with age and reported greater risk of developing periodontal disease in smokers (21, 22). Our study also showed that the periodontal status was better in subjects with higher education. Since the education is indicative of socioeconomic status, this finding is expected. Nevertheless, in our population the high percentage of smokers could make the education and socioeconomic status factor less indicative (23).
It was documented that the genetic variations related to patients and pathogens in certain ethnic groups play a significant role in the pathogenesis of periodontal diseases (24, 25). However, the differences between domicile and immigrant group were not significant concerning periodontal status.
Furthermore, we compared our CPI results for the age group 35-44 with CPI data in the WHO Global Oral Health data bank located at Niigata University, Japan (26). An overview of CPI data in the bank is made for the age groups 15-19 years, 35-44 years and 65-74 years (26).
Table 5 lists the CPI data for the age group 35-44 years in different European countries. It can be noticed that a very high percentage of the population of Knin has score 0 as the highest CPI score: 16%. In Zagreb, the capital of Croatia, a significant improvement in periodontal status was observed from 1986 to 2000 (27), but the percentage of persons having score 0 as the highest score was in 2000 only 6%. We assume that this can be partly attributed to a very high DMFT index among inhabitants of Knin, especially the high number of missing teeth. The percentage of persons exhibiting bleeding on probing (16%) was similar to some weaker European economies: Greece, Romania and Spain, but Denmark as well. Calculus without periodontal pockets was observed in 43.6% which is in the range of Greece, Italy, Portugal, Slovakia and Spain. In general, in more developed countries, as well as in the Croatia’s capital Zagreb, the percentage of persons having shallow and deep pockets is much higher than in the population we have studied. Our results are in range of the countries that also went through transition or belong to the economically weaker countries: Greece, Hungary, Poland, Portugal, Spain and Turkey. This can also be explained by fewer teeth lost due to caries and other reasons in more developed countries which results in fewer sextants excluded.
From the obtained results of our study we can conclude that the population of Knin and the surrounding area exhibit very bad dental status, and not as bad periodontal status which must be interpreted in the context of extremely high number of missing teeth due to caries (average M for the whole population is almost 10).
In general, bad oral status can be attributed to the consequences of the war in the 1990s, the economic transition, and the lack of a national program for oral health promotion. The results of our study, along with the results of epidemiological studies covering other Croatian regions, should be used in planning and organizing oral health care on the national level. In planning and implementation of the national oral health program, the specific epidemiological data for every region should be considered.