Purpose: Dental students learn knowledge and practical skills to provide oral health care to the population. Practical skills must be maintained or continuously developed throughout a professional career. This cross-sectional survey aimed to evaluate the perception of practical skills of dental students and dental-school graduates by national dental associations (NDAs) in Materials and Methods: A questionnaire of 14 items collected information on pre-/postgraduate areas. Results: A total of 25 countries participated (response rate: 69.4%), with 80.0% having minimum requirements for practical skills acquisition and 64.0% starting practical training in the 3rd year of study. In countries where clinical practical work on patients begins in the 2nd year of study, practical skills of graduates are perceived as average, starting in the 3rd year of study as mainly good, starting in the 4th as varying widely from poor to very good. In total, 76.0% of respondents feel that improvements are needed before entering dental practice. Improvements could be reached by treating more patients in dental school (32.0%), increasing the quantity of clinical training (20.0%), or having more clinical instructors (12.0%). In 56.0% of the countries, it is possible to open one's own dental practice immediately after graduation, and in 16.0%, prior vocational training is mandatory. Conclusions: All participating countries in the ERO-FDI zone reported practical training in dental school, most starting in the 3rd year of study. The perception of practical skills of dental students and dental-school graduates among NDAs is very heterogeneous. Reasons for the perceived deficiencies should be further explored.

BACKGROUND:Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic condition of childhood. Temporomandibular joint (TMJ) is among the most commonly affected joints in JIA patients. When JIA involves the TMJ, it may affect condylar growth in the joint; therefore, JIA patients are at risk of unfavourable long-term outcomes from associated joint damage. If undetected, TMJ involvement can lead to various functional disabilities such as reduced mandibular mobility and disorders of the mastication muscles. Limitations in sagittal and vertical mandibular growth can result in micrognathia and anterior open bite with aesthetic and functional restrictions. OBJECTIVE:Genetic factors may play a role in determining which individuals are more prone to develop TMJ disorders or in predicting the severity of the disease process. Therefore, we applied a GWAS approach to identify loci associated with TMJ involvement in a sample of Estonian patients with JIA. Our aim was to address the potential role of genetic susceptibility factors in TMJ-JIA, a condition not previously studied in this context. METHODS:The case group consisted of 55 JIA patients with TMJ involvement and 208 patients without TMJ involvement comprised the control group. The entire cohort was genotyped using the Illumina HumanOmniExpress BeadChip arrays. Imputation was performed using a nationwide reference panel obtained of 2240 individuals whose data were obtained from the Estonian Biobank. RESULTS:We identified six loci as being associated with the risk of TMJ-JIA in Estonian JIA patients. The strongest associations were identified at CD6 rs3019551 (P = 3.80 × 10-6), SLC26A8/MAPK14 rs9470191 (P = 6.15 × 10-6), NLRP3 rs2056795 (P = 8.91 × 10-6) and MAP2K4 rs7225328 (P = 1.64 × 10-5). CONCLUSION:This study provides first insights into the risk-associated loci between JIA and its manifestation in the TMJ. The reported loci are involved in molecular pathways of immunological relevance and likely represent genomic regions that render the TMJ susceptible to involvement by JIA in Estonian patients.

Temporomandibular disorders are a multifactorial disease. Occlusal support and the number of teeth in dentition have significant effects on the masticatory system. The current study aims to review the role of occlusal support in association with findings of temporomandibular disorders. Data sources were PubMed, Web of Science and Google Scholar, with 1411 citations published over the period 1992–2019. The selection criteria stipulated that articles must have reported the association between the number of teeth, occlusal unit, occlusal support and temporomandibular disorders. A total of 15 full-text articles was finally accessed for eligibility in the current review. The studies on temporomandibular disorders were collected from various sources, including articles reporting temporomandibular disorder symptoms ( n=1), temporomandibular disorder signs ( n=5), temporomandibular joint osseous changes ( n=1), temporomandibular joint dysfunction using the Helkimo index ( n=2), and temporomandibular disorder classification ( n=6). Of these articles, significant associations were found between: the number of missing teeth and temporomandibular disorders ( n=5); the number of occlusal units and occlusal supports and temporomandibular disorders ( n=3); the position of the lost occlusal units and temporomandibular disorders ( n=1). Loss of the occlusal unit has more impact on temporomandibular disorders than the loss of posterior teeth. The total loss of unilateral occlusal support seems to be an aetiological factor for temporomandibular disorders, and maintenance of balanced posterior occlusal support has a role in the prevention and management of temporomandibular disorders.

Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic condition of childhood. Genetic association studies have revealed several JIA susceptibility loci with the strongest effect size observed in the human leukocyte antigen (HLA) region. Genome-wide association studies have augmented the number of JIA-associated loci, particularly for non-HLA genes. The aim of this study was to identify new associations at non-HLA loci predisposing to the risk of JIA development in Estonian patients. We performed genome-wide association analyses in an entire JIA case–control sample (All-JIA) and in a case–control sample for oligoarticular JIA, the most prevalent JIA subtype. The entire cohort was genotyped using the Illumina HumanOmniExpress BeadChip arrays. After imputation, 16,583,468 variants were analyzed in 263 cases and 6956 controls. We demonstrated nominal evidence of association for 12 novel non-HLA loci not previously implicated in JIA predisposition. We replicated known JIA associations in CLEC16A and VCTN1 regions in the oligoarticular JIA sample. The strongest associations in the All-JIA analysis were identified at PRKG1 (P = 2,54 × 10−6), LTBP1 (P = 9,45 × 10−6), and ELMO1 (P = 1,05 × 10−5). In the oligoarticular JIA analysis, the strongest associations were identified at NFIA (P = 5,05 × 10−6), LTBP1 (P = 9,95 × 10−6), MX1 (P = 1,65 × 10−5), and CD200R1 (P = 2,59 × 10−5). This study increases the number of known JIA risk loci and provides additional evidence for the existence of overlapping genetic risk loci between JIA and other autoimmune diseases, particularly rheumatoid arthritis. The reported loci are involved in molecular pathways of immunological relevance and likely represent genomic regions that confer susceptibility to JIA in Estonian patients.

Background Osteogenesis imperfecta (OI) is the collective term for a heterogeneous group of connective tissue syndromes.The aim of the current study is to describe dental characteristics, including dentinogenesis imperfecta (DGI), dental wear, occlusal features, and dental caries experience of Vietnamese persons with OI.Methods The sample consisted of 74 individuals with OI classified into type I (n=25), type III (n=24), and type IV (n=25).All participants were examined for DGI through the evaluation of intrinsic color variation, dental wear using Hooper's index, occlusal features (including Angle's classification, overjet, overbite, crossbite) and dental caries experience by using the dmft/DMFT index.Results DGI was found in 62.2% of the sample and was significantly related to OI type III and type IV (p=0.019).Dental wear occurred in 36.5% and was equivalent among OI types.Angle Class III malocclusion was more prevalent in type III (66.7%) and type IV (54.5%) than in type I (37.5%).High prevalence of reverse overjet (60.3%), posterior crossbite (32.2%), and missing teeth (23.3%) were found in the OI sample.The mean dmft/ DMFT score was 3.0/2.2.The dental findings related to dental wear, occlusal features, and dental caries did not show significant differences among type I, III, and IV.Conclusion There was a high prevalence of DGI and dental wear in the Vietnamese OI sample.Occlusal features were related to a high prevalence of class III malocclusion, overjet, open bite, posterior crossbite, and missing teeth.Dental caries experience of persons with OI was at a moderate level.

OBJECTIVES:This study aimed (1) to determine the prevalence of anxiety, depression, and TMJ osseous changes in elderly Vietnamese according to sex and residence, and (2) to investigate the association of temporomandibular joint (TMJ) osseous changes with anxiety, depression, and limitation of mandibular function.METHODS:Elderly people living in Danang, Vietnam were recruited. Participants were screened for anxiety and depression using the self-reported 7-item Generalized Anxiety Disorder Scale (GAD-7) and 9-item Patient Health Questionnaire (PHQ-9), respectively. Participants then self-rated the limitation of their mandibular function using the 20-item Jaw Functional Limitation Scale (JFLS-20) questionnaire. TMJ osseous changes (erosion, flattening, osteophytes, and sclerosis) were evaluated using digital orthopantomography.RESULTS:Of 179 participants aged 65 to 74 years, 17.9% and 35.8% had anxiety and depression symptoms, respectively. Compared with urban residents, rural residents had higher prevalence of anxiety (23.3% vs 12.4%, p = 0.009) and depression (46.62% vs 24.7%, p = 0.019). The prevalence of TMJ osseous changes was 58.1%. The most common TMJ osseous change was flattening (41.3%), followed by erosion (34.6%), sclerosis (16.2%), and osteophytes (7.8%). Participants with or without TMJ osseous changes were comparable in terms of GAD-7 score, PHQ-9 score, and JFLS-20 score and sub-scores.CONCLUSIONS:Anxiety and depression and TMJ osseous changes were prevalent in elderly Vietnamese. Rural residents had higher prevalence of anxiety and depression than urban residents. TMJ osseous changes were not associated with anxiety, depression, or limitation of mandibular function.

Oral microbiome has significant impact on both oral and general health. Polyols have been promoted as sugar substitutes in prevention of oral diseases. We aimed to reveal the effect of candies containing erythritol, xylitol or control (sorbitol) on salivary microbiome. Ninety children (11.3 ± 0.6 years) consumed candies during 3 years. Microbial communities were profiled using Illumina HiSeq 2000 sequencing and real-time PCR. The dominant phyla in saliva were Firmicutes (39.1%), Proteobacteria (26.1%), Bacteroidetes (14.7%), Actinobacteria (12%) and Fusobacteria (6%). The microbiome of erythritol group significantly differed from that of the other groups. Both erythritol and xylitol reduced the number of observed bacterial phylotypes in comparison to the control group. The relative abundance of the genera Veillonella, Streptococcus and Fusobacterium were higher while that of Bergeyella lower after erythritol intervention when comparing with control. The lowest prevalence of caries-related mutans streptococci corresponded with the lowest clinical caries markers in the erythritol group. Daily consumption of erythritol, xylitol or control candies has a specific influence on the salivary microbiome composition in schoolchildren. Erythritol is associated with the lowest prevalence of caries-related mutans streptococci and the lowest levels of clinical caries experience. ClinicalTrials.gov Identifier NCT01062633.

This study aims to evaluate the prevalence of occlusal traits and to assess parents'/caregivers' satisfaction with child's dental appearance and perception of orthodontic treatment need in 4-5-year-old Estonians. Clinical records and plaster casts of 390 children (190 girls and 200 boys, mean age 4.7 years, range 4-5 years) were analyzed. Assessed occlusal traits included deciduous canine and second molar sagittal relationship, overjet, overbite, crowding, midline diastema, crossbite, and scissor bite. Parents'/caregivers' opinions regarding their child's teeth were determined with a questionnaire. The most prevalent occlusal traits were symmetrical sagittal relationship in deciduous canines (78.2%) and molars (75.1%), Class I sagittal relationship in deciduous canines (69.7%) and midline diastema (67.7%). Asymmetrical sagittal canine relationship was registered in 21.8% deciduous canines and in 24.9% second deciduous molars. Parents'/caregivers' perceived orthodontic treatment need was related to Class III sagittal relationship in canines, increased overjet and overbite, negative overbite, and crossbite. Prevalence of most occlusal traits in Estonian children were in line with those reported in neighboring countries. Parents/caregivers were well able to observe occlusal traits that deviated from acceptable occlusion.

Dental fear and anxiety (DFA) has the impact on the development of dental caries. Ethnic background and oral health care system may contribute to DFA model. The aim of the study was to compare DFA in relation to dental health between Estonian and Vietnamese schoolchildren and to determine DFA cutoff point for schoolchildren of two countries. The sample comprised 900 schoolchildren (344 from Estonia and 556 from Vietnam). DFA was measured by using 11 fear items of the modified Dental Subscale of the Children's Fear Survey Schedule (CFSS‐DS). Dental health was recorded by using the dental caries experience index of mixed dentition (dmft/DMFT). Results showed that the mean score of dmft/DMFT in Estonian and Vietnamese schoolchildren was 5.2 ± 3.1 and 4.1 ± 3.2, respectively. The mean score of 11‐item CFSS‐DS of Vietnamese schoolchildren (20.8 ± 9.1) was significantly higher compared with Estonian schoolchildren (15.4 ± 4.4, p < 0.001). The DFA cutoff point of 11‐item CFSS‐DS in Estonian schoolchildren was 17.5, whereas in Vietnamese, it was 24.5. The lower ranking of DFA was significantly associated with Estonian schoolchildren who had more FT (p < 0.001). In conclusion, the level of DFA of schoolchildren was different in Estonia and Vietnam. Vietnamese schoolchildren had higher DFA scores and cutoff point of the modified CFSS‐DS than Estonian schoolchildren. The obtained results suggest that DFA in schoolchildren can be related to oral health care system of each country.

Objective: To analyze data on occlusal traits, orthodontic treatment need and treatment complexity in orthodontically untreated 17-21-year-old Estonians. Materials and methods: Clinical records and plaster casts of 390 untreated young adults (219 females and 171 males, mean age 18.5 years, range 17-21 years) were analyzed. Assessed occlusal traits included first molar and canine sagittal relationship, overjet, overbite, crowding, midline diastema, crossbite and scissor bite. The Index of Complexity, Outcome and Need (ICON) was used to assess orthodontic treatment need and complexity. Participants' opinions regarding their teeth were determined with a questionnaire. Results: The most prevalent occlusal traits were Class I sagittal relationship in canines (76%) and molars (70%), crowding (51%), overbite >= 3.5 mm (48%), the end-to-end sagittal relationship in canines (48%) and overjet >= 3.5 mm (47%). Antero-posterior asymmetry was common both in canines (39%) and molars (37%). According to ICON, 36% of participants had orthodontic treatment need. Conclusions: Desire for orthodontic treatment was associated with crowding and increased overjet, and with no gender difference, participants' main expectation of treatment was an improvement in dentofacial aesthetics. Treatment needs determined with ICON was moderate and in line with the participants' desire for orthodontic treatment.

PURPOSE:To describe oral health behaviours and problems among elderly Vietnamese as well as determine their prevalence of caries and periodontal disease.MATERIALS AND METHODS:This cross-sectional study examined 258 elderly persons aged 65-74 years living in Danang, Vietnam. All subjects self-reported oral health behaviour and problems. Dental caries was assessed using the DMFT index. Periodontal status was evaluated with the modified Community Periodontal Index, whereby all teeth were examined for gingival bleeding and periodontal pocket depth (PPD), and the index teeth were assessed for clinical attachment loss (CAL).RESULTS:48.4% of the elderly brushed their teeth at least twice a day; 34% had never visited a dentist; 27.8% often had difficulty chewing foods. Of the sample, mean DMFT was 14.3 ± 8.7 (DT = 6.4 ± 5.5, MT = 7.7 ± 7.1, and FT = 0.2 ± 0.9), 88.8% had untreated caries, 21.0% had at least one tooth with a PPD ≥ 6 mm, and 49.8% had at least one sextant with CAL ≥ 6 mm. The mean number of teeth per person was 22.0, of which 19.5 teeth (88.6%) had gingival bleeding, 7.7 teeth (37.1%) with a PPD 4-5 mm, and 0.8 teeth (5.0%) with a PPD ≥ 6 mm. The mean number of sextants with CAL 4-5 mm and CAL ≥ 6 mm were 2.5 ± 2.0 and 1.3 ± 1.7, respectively. Rural residence was found to be negatively associated with MT, FT, and healthy periodontal status (p < 0.05).CONCLUSIONS:Dental diseases are prevalent among elderly Vietnamese owing to a lack of awareness of oral health self-care behaviours, especially among those living in rural areas. This suggests that an oral health care programme is required to improve the oral health status of elderly Vietnamese.

The study aims to investigate how mothers’ oral health behaviour and perception thereof influence the dental health in their children.

Introduction: Temporomandibular disorders (TMD) are a group of disorders that may cause functional limitations.The aim of the study was to compare the differences in dental status, oral behaviour, and mandibular functional limitations between TMD and non-TMD elderly people in Vietnam.Methodology: The sample consisted of 146 TMD and 112 non-TMD elderly.The dental and periodontal status were evaluated with DMFT and CPI indices.The participants self-rated frequency of oral behaviour activities (21-item Oral Behaviour Checklist) and mandibular functional limitations (20-item Jaw Functional Limitation Scale).Results: The mean number of missing teeth in TMD group was 9.6 ± 8.6, while it was 7.6 ± 6.4 in non-TMD group (p = 0.036).Gingival bleeding in TMD group was detected at 18.3 ± 10.2 teeth, which was less than in non-TMD group (21.0 ± 8.7, p = 0.023).The mean number of sextants with a 0-3 mm clinical attachment loss was high for non-TMD group (1.4 ± 2.0, p = 0.021), while the mean number of excluded sextants was high for TMD group (1.3 ± 1.8, p = 0.037).The TMD elderly group reported more frequent instances of "Hold, tighten, or tense muscles" than non-TMD group.No significant differences were found in the self-rated mandibular functional limitations between the two groups.Conclusion: TMD were associated with missing teeth and periodontal diseases.There was no association between TMD and mandibular functional limitations.The elderly suffering from TMD tended to have increased frequency of holding, tightening, or tensing muscles.

The aim of study was to determine the association between signs of temporomandibular disorders (TMD), occlusal support, and alterations in the craniofacial structure of elderly Vietnamese by using cephalometric analysis. The cross-sectional study consisted of 244 participants aged 65-74 years. Participants were examined for signs of TMD, including limited mouth opening, temporomandibular joint (TMJ) crepitus, TMJ tenderness, and muscle tenderness. Dentition was divided into four occlusal support zones based on occluding pairs of posterior teeth by using Eichner's classification: Class A = 4 support zones; Class B = 1-3 support zones or only contact in anterior teeth; Class C = 0 support zones. Fifteen angular and seven linear parameters were used for sagittal craniofacial skeleton analysis. 10.3% of participants had limited mouth opening, 49.6% TMJ crepitus, 16.3% TMJ tenderness, and 24.2% muscle tenderness; 45.5% had Class A occlusal support, 38.5% Class B, and 16.0% Class C. Those with Class C had significantly smaller ramus inclination, articular angle, and angles formed by the mandibular plane and shorter facial height compared to Class A and Class B (P < .001). TMD signs were significantly associated with: angles formed by mandibular plane, gonial angle, cranial base angle, effective mandibular length, and anterior facial height (P < .05). The alteration of craniofacial structures was significantly associated with TMD signs among elderly Vietnamese. The higher number of lost occlusal support zones, the more significant the changes to craniofacial structures.

Purpose: The aim of this study was to analyze the associations between missing teeth, occlusal support, and temporomandibular disorders (TMD) among elderly Vietnamese. Materials and Methods: The study consisted of 145 TMD and 112 non-TMD (control group) participants aged 65 to 74 years. TMD was evaluated using Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) Axis I. An occlusal unit (OU) was defined as the cusp of a tooth coupled with the fossa of its antagonist tooth. A premolar pair was counted as one OU and a molar pair as two OUs. Dentition was divided into four occlusal support zones (OSZs) based on occluding pairs of posterior teeth by using Eichner classification: Class A had 4 OSZs, Class B had 1 to 3 OSZs or only anterior teeth, and Class C had no OSZ. Results: The TMD group lost significantly more posterior teeth (mean +/- SD 5.1 +/- 4.7) than the control group (4.0 +/- 3.9, P =.033). The mean SD OUs of the TMD and control groups were 5.1 +/- 4.6 and 6.0 +/- 4.3, respectively, which was nonsignificant (NS). The distribution of Class A (40.7%), Class B (40.0%), and Class C (19.3%) among the TMD group was not significantly different from the control group (50.0%, 38.4%, and 11.6%, respectively, NS). The odds of having TMD were positively associated with total unilateral loss of OUs (OR = 3.4, 95% CI = 1.2-9.4, P =.020) and total bilateral loss of OUs (OR = 2.7, 95% CI = 1.2-6.6, P =.027). Conclusion: Total loss of OSZs on one or both sides of the mouth were found to be predictors of TMD among elderly Vietnamese.

Background: To assess the prevalence of the symptoms and signs of temporomandibular disorders (TMDs) and determine the prevalence of TMDs among elderly Vietnamese aged 65–74 years old. Methods: A cross-sectional study was conducted among 258 participants aged 65–74 years old (128 females and 130 males) using two strategies for TMD diagnosis: a clinical examination of the temporomandibular joint and its associated structures using the Diagnostic Criteria for Temporomandibular Disorders Axis I; and a set of 14 questions regarding TMD symptoms to obtain anamnestic data. Results: The prevalence of TMD symptoms was: headache 49.6%; temporomandibular joint noise 28.0%; orofacial pain 25.2%; jaw locking 3.1%; 62.5% of participants had at least one TMD symptom. Headaches were more prevalent in females than males ( p =0.009) and rural than urban residents ( p <0.001). The most frequent signs were temporomandibular joint crepitus (50.4%), clicking (48.1%) and mouth-opening deviation (37.6%). Temporomandibular joint crepitus and mouth-opening deviation were more frequent among rural than urban ( p =0.024 and p <0.001, respectively). TMD was found in 56.6% of the total sample. Of the TMD sufferers, 37.6% were diagnosed with disc displacement, 34.9% with degenerative joint disease, 3.5% with myalgia and 1.2% with arthralgia. Conclusions: More than half of elderly Vietnamese have at least one TMD symptom. TMD sounds were the most common clinical sign of TMD. There were no differences between the genders or place of residence and TMD diagnosis. Disc displacement and degenerative joint disease were most prevalent among elderly Vietnamese.

The aim of this study was to evaluate the distribution of occlusal traits and orthodontic treatment need and complexity in Estonian 7‐ to 10‐year‐old children. This data provides solid information for planning of orthodontic care. Data of 392 Estonian children (198 girls and 194 boys, mean age 9.0 years, range 7.1–10.4 years) was analysed in this cross‐sectional study. Assessed traits included first molar and canine sagittal relationship, overjet, overbite, crowding, midline diastema, crossbite, and scissor bite. Orthodontic treatment need and complexity were assessed using the Index of Complexity, Outcome, and Need. Parents' opinion regarding their child's teeth was determined using a questionnaire. The most prevalent occlusal traits were canine class I sagittal relationship (73.7%), midline diastema (73.0%), molar class I sagittal relationship (57.4%), and overbite ≥3.5 mm (51.8%). According to the Index of Complexity, Outcome, and Need, 64.3% of Estonian elementary school children were in need of orthodontic treatment. Treatment complexity was simple in 12.5%, mild in 38.8%, moderate in 22.7%, difficult in 14.0%, and very difficult in 12.0% of the children. Approximately 66.4% of the parents felt that their child needed orthodontic treatment. This study confirms earlier findings indicating that the most frequent sagittal relationship is class I in the first molars and class I in the canines. However, the sagittal relationship was asymmetric in more than half of the children. Correlation between objectively defined treatment need and parents' desire for treatment was high in Estonia.

The aim of the study was to (a) analyse dental occlusion and determine the need for orthodontic treatment of persons with osteogenesis imperfecta (OI) in comparison with the healthy population and (b) investigate the associations between OI and malocclusion. A case-control study included 26 OI persons and 400 healthy participants (control group). Occlusal features and the need for orthodontic treatment were defined according to Dental Health Component-Index of Orthodontic Treatment Need and Dental Aesthetic Index. Results showed that Angle Class I, II, and III relationship was found in 23.1%, 3.8%, and 73.1% of OI group, and in the control group, it was 67%, 17.5%, and 15.5%, respectively. OI group had significantly higher prevalence of reverse overjet>1mm (76.9%), missing teeth (42.3%), posterior crossbite (34.6%), and open bite>2mm (19.2%) compared to the control group (8.5%, 2.2%, 6.2%, and 3.5%, respectively). OI group had less incisal segment crowding and more incisal segment spacing than the control group (p<0.05). The need for orthodontic treatment of OI group according to Dental Health Component-Index of Orthodontic Treatment Need and Dental Aesthetic Index was 88.5% and 61.5%, respectively, while in the control group, it was 24.8% and 51.8%. The malocclusion in OI persons was associated with reverse overjet>1mm (OR=13.3, 95% CI=3.9-44.7, p<.001), Angle Class III malocclusion (OR=8.0, 95% CI=2.0-30.8, p=.003), and missing teeth (OR=4.7, 95% CI=1.0-22.4, p=.049). In conclusion, there is the high probability of malocclusion in OI persons. Persons with OI require early orthodontic treatment because of significant correlation of OI disease with Angle Class III malocclusion, reverse overjet, and missing teeth.

Apical periodontitis (AP) is an inflammatory disease around the apex of a tooth root. Reported prevalence of AP ranges from 27% to 83% while the data about most post-Soviet countries are still missing. Knowing the prevalence of AP within a certain population helps to plan the treatment need and evaluate the success of endodontic interventions. We aimed to collect data about prevalence and determining factors of AP for the first time in Estonia.

Background: Apical periodontitis (AP) is an inflammatory disease affecting periradicular tissues. It is a widespread condition but its etiopathogenetic mechanisms have not been completely elucidated and the current treatment options are not always successful.Purpose: To compare oxidative stress (OxS) levels in the saliva and the endodontium (root canal [RC] contents) in patients with different endodontic pathologies and in endodontically healthy subjects.Patients and methods: The study group of this comparison study included 22 subjects with primary chronic apical periodontitis (pCAP), 26 with posttreatment or secondary chronic apical periodontitis (sCAP), eight with acute periapical abscess, 13 with irreversible pulpitis, and 17 healthy controls. Resting saliva samples were collected before clinical treatment. Pulp samples (remnants of the pulp, tooth tissue, and/or previous root filling material) were collected under strict aseptic conditions using the Hedstrom file. The samples were frozen to -80 degrees C until analysis. OxS markers (myeloperoxidase [MPO], oxidative stress index [OSI], 8-isoprostanes [8-EPI]) were detected in the saliva and the endodontium.Results: The highest MPO and 8-EPI levels were seen in pCAP and pulpitis, while the highest levels of OSI were seen in pCAP and abscess patients, as well as the saliva of sCAP patients. Controls showed the lowest OxS levels in both RC contents and saliva. Significant positive correlations between OxS markers, periapical index, and pain were revealed. Patients with pain had significantly higher OxS levels in both the endodontium (MPO median 27.9 vs 72.6 ng/mg protein, p=0.004; OSI 6.0 vs 10.4, p<0.001; 8-EPI 50.0 vs 75.0 pg/mL, p<0.001) and saliva (MPO 34.2 vs 117.5 ng/mg protein, p<0.001; 8-EPI 50.0 vs 112.8 pg/mL, p<0.001) compared to pain-free subjects.Conclusion: OxS is an important pathomechanism in endodontic pathologies that is evident at both the local (RC contents) and systemic (saliva) level. OxS is significantly associated with dental pain and bone destruction.