The Fluoride Ion Release from Ion-Releasing Dental Materials after Surface Loading by Topical Treatment with Sodium Fluoride Gel.

The study aimed to investigate the rechargeability of ion-releasing dental material specimens immersed in distilled water for 25 months, which depleted their ion-releasing ability. Four restorative dental materials (alkasite composite, giomer, glass-ionomer, and composite material) presented with 24 specimens were studied after topical treatment with a concentrated fluoride gel. The effect of resin coating on the ion uptake and release was investigated on additional 42 specimens of restorative dental materials with coatings. The composite materials were coated with two adhesive systems, whereas the glass-ionomer was coated with the special coating resin. After topical fluoride exposure, ion release and specimen mass were measured at 1, 2, 3, 4, 5, 6, 7, and 14-day intervals using an ion-selective electrode and an analytical balance, respectively. The cumulative fluoride levels for the uncoated specimens of alkasite composite were significantly higher than those of giomer and glass-ionomer cement, with no statistically significant difference between the latter two materials. The conventional composite had the lowest cumulative concentration of fluoride ions (p < 0.05). The adhesive systems affected the fluoride recharge and reduced the ion concentrations absorbed by the specimens. Specimens coated with universal adhesive showed significantly higher ion release compared to universal fluoride-releasing adhesive or special coating resin for glass-ionomers (p < 0.05). No statistically significant change in specimen mass was observed during the 14-day period. Surface coating with adhesive systems as well as special coating resin for glass-ionomers affects the fluoride recharge process.

Changes in Medication Prescribing Due to COVID-19 in Dental Practice in Croatia-National Study.

The 2019 coronavirus pandemic (COVID-19) has affected clinical practice and, consequently, drug prescribing in dental practice. We investigated how the pandemic affected the prescribing behavior of dentists in Croatia. Data on prescribing practices for this study were provided by the Croatian Health Insurance Institute. The analysis included the number of prescriptions, costs, and the number of packages prescribed. The World Health Organization's defined daily dose per 1000 inhabitants (DID) per day was used as an objective utilization comparison. During the first pandemic year, prescribing practice changed the most. Wide-spectrum antibiotics, analgesics, and antiseptics showed the highest trend in change. A statistically significant change in prescribing practices during the pandemic period was noted for amoxicillin with clavulanic acid, ibuprofen, and ketoprofen which showed an increase in trend, while cephalexin and diclofenac showed a statistically significant decrease. The highest increase in trend was recorded for azithromycin, at +39.3%. The COVID-19 pandemic has been associated with a marked increase in medication utilization, especially in the first year of the pandemic. The increase in wide-spectrum antibiotic classes needs to be addressed and regulated so that patients accept that antibiotics are not a substitute for dental treatment and dentists always start treatment with narrow-spectrum antibiotics regardless of specific times, as is the case with the pandemic.

Salivary parameters and periodontal inflammation in obstructive sleep apnoea patients.

The aim of this cross-sectional study was to objectively assess the salivary flow rate and composition and periodontal inflammation in obstructive sleep apnoea (OSA) patients. The subjects, who underwent whole-night polysomnography or polygraphy, were referred for saliva sampling and periodontal examination. According to the severity of OSA based on the Apnoea Hypopnea Index (AHI) value, the subjects were classified into groups: no OSA (AHI < 5; N = 17), mild to moderate OSA (AHI 5-29.9; N = 109), and severe OSA (AHI > 30; N = 79). Salivary flow rate, pH, salivary electrolytes, and cortisol were measured from collected saliva samples. Periodontal examination included assessment of the number of teeth, dental plaque, bleeding on probing and periodontal measurements: gingival recession, probing pocket depth, clinical attachment level (CAL) and periodontal inflamed surface area (PISA) score. There were no significant differences in salivary flow rate, salivary pH, salivary electrolyte concentrations or electrolyte ratios among the groups classified according to the severity of OSA. However, subjects without OSA had higher salivary cortisol concentrations than OSA groups (p < 0.001). Increased plaque scores were associated with a higher AHI (r = 0.26; p = 0.003). According to the salivary flow rate, subjects with hyposalivation and reduced salivation had higher concentrations of salivary electrolytes and lower salivary pH than subjects with normal salivation. Subjects with hyposalivation had an increased Mg/PO4 ratio (p < 0.001) and a reduced Ca/Mg ratio (p < 0.001). Furthermore, subjects with severe OSA tended to have higher CALs and plaque volumes. In conclusion, under pathological conditions, such as OSA, multiple interactions might impact salivary flow and electrolyte composition. Complex interrelationships might affect the integrity of oral health, especially considering OSA severity, inflammation, concomitant diseases and medications.

Use of sedative pharmacological agents among biomedical students during the coronavirus disease 2019 pandemic: a cross-sectional pilot study.

AIM: To assess the use of sedative pharmacological agents (SPA) among students in Croatia during the coronavirus disease 2019 pandemic. METHODS: An online questionnaire, specially developed for the research purposes, was completed by 1403 students. The questionnaire inquired about general characteristics, the effect of the pandemic and earthquakes on students' lives, and SPA use (method of purchasing, modes, and frequency). RESULTS: In the total sample, the SPA use before the pandemic significantly correlated with that after the beginning of the pandemic (P<0.001). After the beginning of the pandemic, medical students used significantly more SPA than other biomedical students (P=0.017). When compared with non-biomedical students, biomedical students did not differ significantly in SPA use after the beginning of the pandemic (P=0.365). CONCLUSION: Medical students used more SPA than other biomedical students. Biomedical students did not differ in SPA use from non-biomedical students.

Subgingival Microbiota Profile in Association with Cigarette Smoking in Young Adults: A Cross-Sectional Study.

While smoking is recognized as one of the factors for the development and progression of periodontal diseases, a relation between the composition of the subgingival microbiota and smoking is yet to be elucidated. The aim of this study was to investigate the prevalence of subgingival bacteria in young smokers and non-smokers without clinical signs of periodontal disease. In this cross-sectional study, performed at the Department of Pharmacology, School of Dental Medicine, University of Zagreb, we enrolled 32 periodontally healthy smokers and 32 non-smokers, aged 25-35 years old. The number of oral bacteria and the prevalence of particular bacteria were assessed for each subject. Subgingival plaque samples were collected with sterile paper points from two first molars for microbiological analyses with MALDI-TOF mass spectrometry. In smokers, a significantly higher prevalence of Actinomyces odontolyticus was observed compared to non-smokers, and a significantly lower prevalence of Streptococcus sanguinis was observed compared to non-smokers. Smoking affects the composition of subgingival microbiota, either via depletion of beneficial bacteria or the increase in pathogenic bacteria.

Dentists' practice and compliance with current guidelines of infective endocarditis prophylaxis- National survey study.

BACKGROUND: The objective of this study was to assess the attitude, practice, and knowledge of Croatian dentists regarding infective endocarditis (IE) prophylaxis. MATERIAL AND METHODS: A cross-sectional, self-reporting questionnaire survey was conducted with the participation of 348 Croatian dentists. The questionnaire was designed to collect information on participants' work experience, place of work, their attitudes related to the treatment of IE-risk patients, knowledge and adherence to IE antibiotic prophylaxis guidelines. RESULTS: Knowledge and adherence to the current guidelines decreased with the higher years of experience. Compliance with the current guidelines varied, mostly because of respondents' insecurity regarding which guidelines to follow. AHA guidelines have been most frequently the first choice (25% participants). Surprisingly, 23% of dentists didn't follow any of the official guidelines. The majority of participants (68%) have declared a lack of preparedness or willingness to treat the patients at risk of IE. Dentists with specialty or working at university/hospital have shown a higher level of knowledge and preparedness to treat IE-risk patients. CONCLUSIONS: The lack of knowledge of guidelines and consequent inconsistencies in IE antibiotic prophylaxis in Croatian dental practice indicates the need for urgent improvement. Key words:Antibiotic prophylaxis, dentistry, infective endocarditis.

Cigarette smoking and its consequences on periodontal health in teenagers: a cross-sectional study.

OBJECTIVES: Smoking has been extensively investigated as a risk factor for periodontal disease and many studies have confirmed it. The aim of this study was to show data from Croatia on periodontal health among high school students, with the focus on association of tobacco use and oral hygiene habits, and the periodontal parameters. METHODS: Pocket probing depth (PPD), bleeding on probing, supragingival calculus, and oral hygiene habits were recorded for each examinee out of 517 high school students. PPD was measured at 4 interproximal sites on all first molars and central incisors (index teeth). RESULTS: There were 34.6% smokers among subjects, who started smoking on average at the age of 14. More than half of the smokers (55.3%) smoked 1-10 cigarettes per day and intensity of smoking increased with age. PPD was significantly greater (p = 0.012) in smokers (1.69 mm) than in non-smokers (1.59 mm). In non-smoking subjects, increased values of PPD were in direct proportion to the reduced frequency of brushing, while there was no difference in smokers. The number of cigarettes smoked and duration of smoking had a great influence on PPD. Smokers had on average more teeth with supragingival calculus than non-smokers, while non-smokers had more bleeding on probing, and the difference was statistically significant (p < 0.001). CONCLUSIONS: This study indicated that cigarette smoking was associated with decreased periodontal health even in this young population. Irregular oral hygiene was associated with decreased periodontal health only in non-smokers. Therefore, it should be important to inform young smokers about the negative effects of cigarette smoking on periodontal health, to provide consultations and reinforce smoking prevention measures.

Fluoride-Releasing Restorative Materials: The Effect of a Resinous Coat on Ion Release.

OBJECTIVE: To determine the effect of two adhesive systems and a glass ionomer coating resin on fluoride release and concurrent pH changes over a period of 168 days. MATERIAL AND METHODS: Four restorative materials were investigated: a giomer Beautiful II, an "alkasite" material Cention, a conventional composite Filtek Z250, and a glass ionomer cement Fuji IX Extra. Light-cured composite specimens were coated using G-aenial Bond and Clearfil Universal Bond Quick. Glass ionomer specimens were coated using GC Fuji Coat LC. Uncoated specimens were used as references. Quantitative fluoride release and pH changes were measured after1 h, 24 h, 2 days, 7 days, 28 days, 84 days, and 168 days. RESULTS: The cumulative fluoride release after 168 days increased for uncoated specimens in the following order: Filtek Z250 < Beautifil II < Cention < Fuji IX Extra. A comparatively lower fluoride release was measured for the composites coated with Clearfil Universal Bond Quick, with cumulative values after 168 days increasing in the following order: Filtek Z250 < Beautifil II < Cention. The composites coated with G-aenial Bond showed lower fluoride release compared to the uncoated specimens, with cumulative values increasing in the following order: Filtek Z250 < Beautifil II < Cention. The composites coated with G-aenial Bond showed pH values in the acidic range (4.4-5.7) after 1 h and 24 h. CONCLUSION: Fluoride release varied among the investigated restorative materials and depended on the use of dental adhesives and coatings. The pH of all materials, coating types and time points varied.

The epidemiological and clinical features of odontogenic infective endocarditis.

Antibiotic prophylaxis (AP) of infective endocarditis (IE) in dental practice is a controversial topic. We evaluated the characteristics of the odontogenic IE and assessed the practice and sources of information pertaining to the topic utilized by the Croatian dentists. We conducted a retrospective review of consecutive medical charts of adult patients with IE, admitted to the University Hospital for Infectious Diseases in Zagreb, Croatia, between January 2007 and December 2017. In addition, a cross-sectional, self-reporting questionnaire survey was conducted with participation of 348 Croatian dentists. Of the 811 admissions for suspected IE (40.3% of all Croatian and 92.1% of all Zagreb hospitals), 386 patients were confirmed as definite IE: 68 with odontogenic IE and 318 with IE of other origin. Their first hospital admissions were analyzed. Definite odontogenic IE was defined as a positive echocardiographic result in conjunction with two separate positive blood cultures showing exclusive oral cavity pathogen or Streptococcus viridans associated with current or recent (< 1 month) dental, periodontal, or oral cavity infection. The annual number of new odontogenic IE patients appeared constant over time. In 91.2% of the cases, odontogenic IE was not preceded by a dental procedure; poor oral health was found in 51.5% of patients, and 47.1% had no cardiac condition that increases the IE risk. In-hospital mortality was 5.1% with conservative treatment and 4.5% with cardiac surgery and was much lower for odontogenic IE than in non-odontogenic IE (14.6% and 34.4%, respectively). An increasing number of admissions for non-odontogenic IE were observed in parallel with an increasing number of staphylococcal IE. Surveyed dentists (500 invited, 69.6% responded) were aware of the AP recommendations, but were largely reluctant to treat patients at risk. In people with poor oral health, AP should be considered regardless of cardiac risk factors. Improvement of oral health should be the cornerstone of odontogenic IE prevention.

The rise in glucose concentration in saliva samples mixed with test foods monitored using a glucometer: An observational pilot study.

OBJECTIVES: The aim of this study was to quantify the changes in glucose concentration in unstimulated saliva samples mixed with finely crushed salted sticks or oat meal using a readily available portable glucometer. METHODS: Glucose measurements were taken every 10 min during a 1 h monitoring period, for a total of 14 saliva samples mixed with test foods. Salivary amylase activity was measured immediately after saliva collection (T0) and after 1h (T60). Level of salivary amylase activity was correlated with an increase in glucose concentration. RESULTS: We observed significant differences in the rate of increase in glucose concentration between the two different test foods, with salted sticks leading to greater increase in glucose concentration. No significant association was found between salivary amylase activity and the rate of increase in glucose concentration. The mean level of amylase activity at T60 was higher than that at T0, but this difference was not significant. CONCLUSIONS: This pilot study presents glucose release rate characteristics from specific food particles mixed with saliva in vitro suggesting that the same process takes place in the oral cavity. However, the characteristics of this process when occurring in the mouth would expectedly be modified by different factors such as rinsing effect of salivary flow, oral temperature, etc. Prolonged release of low molecular carbohydrates such as maltose and glucose from food particles can be considered cariogenic and therefore unfavorable for individuals with other risk factors contributing to the development of dental caries.

Fluoride Release from Glass Ionomer with Nano Filled Coat and Varnish.

OBJECTIVE: This in vitro study compares the fluoride release from microlaminated glass ionomer based on glass hybrid technology coated with two different surface coating agents. MATERIALS AND METHODS: A total of 18 samples were divided into three groups of six samples each: (1) glass ionomer Equia Forte Fil coated with Equia Forte Coat (Equia+EC), (2) glass ionomer Equia Forte Fil coated with GC Fuji Varnish (Equia+VC) and (3) uncoated glass ionomer Equia Forte (EQUIA cont). Fluoride release was measured using an ion-selective electrode (ORION EA 940) after 24 hours, 4 days, 30 days and 64 days. Repeated measures ANOVA, multiple comparisons, Tukey's test and paired t-test were used to test the differences between the groups. RESULTS: The differences between the groups and four time points were statistically significant (ANOVA, p<0.0001). Cumulative fluoride ion release after 64 days was 66.01 mg/l, 123.54mg/l and 203.22 mg/l for EQUIA+EC, EQUIA+VC and EQUIA cont, respectively. All the differences were statistically significant except the difference between EQUIA+VC and EQUIA cont after 24 hours. CONCLUSIONS: The amount of released fluoride was significantly lower in the samples coated with nanofilled surface coating agent compared to the samples coated with varnish and uncoated samples.

Effect of pH, fluoride and hydrofluoric acid concentration on ion release from NiTi wires with various coatings.

Aim was to determine effect of pH, fluoride (F-) and hydrofluoric acid concentration (HF) on dynamic of nickel (Ni2+) and titanium (Ti4+) ions release. Nickel-titanium wires with untreated surface (NiTi), rhodium (RhNiTi) and nitride (NNiTi) coating were immersed once a week for five min in remineralizing agents, followed by immersion to artificial saliva. Ion release was recorded after 3, 7, 14, 21 and 28 days. Pearson correlations and linear regression were used for statistical analysis. Release of Ni2+ from NiTi and NNiTi wires correlated highly linearly positively with HF (r=0.948 and 0.940, respectively); for RhNiTi the correlation was lower and negative (r=-0.605; p<0.05). The prediction of Ti4+ release was significant for NiTi (r=0.797) and NNiTi (r=0.788; p<0.05) wire. Association with F- was lower; for pH it was not significant. HF predicts the release of ions from the NiTi wires better than the pH and F- of the prophylactic agents.

The Effect of Salivary Calcium and Fluoride Toothpaste on the Formation of KOH-Soluble Fluoride: In Vitro Study.

OBJECTIVE: The aim of this in vitro preliminary study was to assess the effect of smokers' saliva (assuming their higher calcium concentration) in combination with fluoridated toothpaste on the enamel uptake of alkali-soluble (KOH-soluble) fluoride. MATERIALS AND METHODS: Four enamel slabs were cut from each of 14 impacted third molars and randomly assigned into 4 groups. Unstimulated saliva samples were collected from two age and sex matched volunteers. One of the samples was taken from a heavy smoker and the other sample was taken from a non-smoker. Two groups (A and B) were shaken in saliva (A in smoker's saliva, B in nonsmoker's saliva) for 5 min and then shaken for 3 min in a toothpaste/deionized water slurry (1:3 w/w). One of the groups (group C) received no saliva treatment and was only shaken in toothpaste slurry for 3 min. The treatment was repeated after a 6-hour period. One of the groups (D) served as a control group with no treatment. RESULTS: Calcium concentration in the smoker's saliva was higher than in the nonsmoker's saliva. The enamel uptake of KOH-soluble fluoride in group A was significantly higher than that in the other two treatment groups, B and C. The enamel uptake of KOH-soluble fluoride in all 3 groups was statistically different from that in the control group. CONCLUSION: These results demonstrate that saliva collected from a heavy smoker, which had higher salivary calcium concentration, enhances enamel uptake of alkali-soluble fluoride and encourages us to conduct a large-scale study.

Time-related Changes in pH, Buffering Capacity and Phosphate and Urea Concentration of Stimulated Saliva.

PURPOSE: To quantify changes in pH, buffering capacity and hydrogen carbonate, phosphate, protein and urea concentrations of stimulated saliva which occur during a 30-min measurement delay after saliva collection. The correlation between time-related chemical changes and changes of salivary pH and buffering capacity was assessed in order to explain the observed changes in salivary pH and buffering capacity. MATERIALS AND METHODS: Stimulated saliva samples were collected from 30 volunteers after inducing salivation by chewing a piece of parafilm. Measurements of salivary variables were made immediately after saliva collection and again 30 min later, during which time the specimens were exposed to the atmosphere in collection cups at room temperature. RESULTS: Postponement of measurements resulted in a significant increase in pH and a significant decrease of buffering capacity, phosphate and urea concentration. The results suggest that the time-related pH increase could primarily be attributed to loss of dissolved carbon dioxide from saliva, and confirm the importance of hydrogen carbonate in the neutralisation of hydrogen ions, but they do not support the principle of catalysed phase-buffering for the hydrogen carbonate buffer system in saliva. A decrease in phosphate and urea concentration affects salivary buffering capacity. CONCLUSION: This study emphasises the importance of the standardisation of measurement time when measuring salivary pH, buffering capacity, phosphate and urea concentrations following the collection of saliva in order to obtain comparable results. It also provides a partial explanation of the mechanisms underlying the observed changes of pH and buffering capacity over time.

The cariostatic mechanisms of fluoride.

UNLABELLED: This article discusses the possible cariostatic mechanisms of the action of fluoride. In the past, fluoride inhibition of caries was ascribed to reduced solubility of enamel due to incorporation of fluoride (F-) into the enamel minerals. The present evidence from clinical and laboratory studies suggests that the caries-preventive mode of action of fluoride is mainly topical. There is convincing evidence that fluoride has a major effect on demineralisation and remineralisation of dental hard tissue. The source of this fluoride could either be fluorapatite (formed due to the incorporation of fluoride into enamel) or calcium fluoride (CaF2)-like precipitates, which are formed on the enamel and in the plaque after application of topical fluoride. Calcium fluoride deposits are protected from rapid dissolution by a phosphate -protein coating of salivary origin. At lower pH, the coating is lost and an increased dissolution rate of calcium fluoride occurs. The CaF2, therefore, act as an efficient source of free fluoride ions during the cariogenic challenge. The current evidence indicates that fluoride has a direct and indirect effect on bacterial cells, although the in vivo implications of this are still not clear. CONCLUSION: A better understanding of the mechanisms of the action of fluoride is very important for caries prevention and control. The effectiveness of fluoride as a cariostatic agent depends on the availability of free fluoride in plaque during cariogenic challenge, i.e. during acid production. Thus, a constant supply of low levels of fluoride in biofilm/saliva/dental interference is considered the most beneficial in preventing dental caries.

Antimicrobial effect of different brushing frequencies with fluoride toothpaste on Streptococcus mutans and Lactobacillus species in children with fixed orthodontic appliances.

OBJECTIVE: To evaluate the antimicrobial effect of different frequencies of brushing with fluoride toothpaste on the levels of salivary mutans streptococci and lactobacilli in children undergoing fixed orthodontic treatment. METHODS: The study included 22 patients scheduled for fixed orthodontic therapy distributed between 2 groups with different hygiene regimes. All the subjects received identical braces, bands, and brackets bonded with the same material. Stimulated saliva samples were obtained before placement of the appliance and at 6, 12, and 18 weeks during the therapy. Saliva samples were cultured on selective microbial agar for the detection of microorganisms. RESULTS: Salivary mutans streptococci were significantly suppressed throughout the experimental period in the group that brushed 4 times a day as compared to the group that brushed twice a day. Salivary lactobacilli were not significantly affected by the frequency of brushing with 0.32% sodium fluoride (NaF) toothpaste. CONCLUSIONS: The use of 0.32% NaF-containing toothpaste more than 3 times a day has effective antimicrobial activity on mutans streptococci but not lactobacilli in the saliva of children with fixed orthodontic appliances.

Periodontal diseases at the transition from the late antique to the early mediaeval period in Croatia.

OBJECTIVE: We tested the hypothesis that the transition from the late antique to the early mediaeval period in Croatia had a negative impact on the periodontal health. METHODS: 1118 skulls were examined for dental calculus, alveolar bone resorption, fenestrations, dehiscences and root furcation involvement. RESULTS: The prevalence of teeth with calculus varied from 40.7% in the LA sample of continental parts of Croatia to 50.3% in the LA sample of Adriatic Croatia. The prevalence of alveolar bone resorption ranged between 21.2% in the EM sample from continental Croatia and 32.3% in the LA sample from Adriatic Croatia. The prevalence of individuals with alveolar bone dehiscences varied from 8.6% in the LA sample from continental Croatia up to 15.0% in the EM sample from Adriatic Croatia. The prevalence of individuals with alveolar bone fenestrations varied from 21.5% in the LA sample from Adriatic Croatia up to 36.2% in the LA sample from continental Croatia. The prevalence of individuals with exposed root bifurcations or trifurcations varied from 9.0% in the EM sample from Adriatic Croatia up to 20.7% in the EM sample from continental Croatia. Statistically significant differences were found between samples. CONCLUSION: The transition from the late antique to the early mediaeval period in Croatia did not have a negative impact on periodontal health. Studies of periodontal health of ancient populations should be performed to provide a better and more reliable reconstruction of living conditions in the past.

Orthodontic anomalies and malocclusions in Late Antique and Early Mediaeval period in Croatia.

OBJECTIVE: Malocclusions are relative infrequently analysed in bioarchaeological investigations and if investigated the samples are very small. This research provides analysis of orthodontic anomalies of even 1118 individuals from the Late Antique (LA) and Early Mediaeval (EM) period. Aims were to describe the prevalence of orthodontic anomalies in this historical period and to analyse which orthodontic anomalies are best suitable for bioarchaeological investigations. METHODS: 1118 skulls were examined for anomalies of tooth number, tooth displacement (rotation, malposition, diastema and crowding) as well as for malocclusions. RESULTS: The prevalence of hypodontia in the LA was 41.02% and 30.61% in the EM sample. Tooth displacement was noticed in 15.63% individuals from the LA and in 12.42% individuals from EM. About 26% of the LA sample and 7.19% of the EM sample were affected with tooth crowding and the difference was statistically significant. CONCLUSION: Orthodontic anomalies affecting only one tooth or group of teeth are more suitable for examination in bioarchaeological investigations than orthodontic features requiring presence of both jaws and all or almost all teeth. Clinical investigation protocols and methodology should be adopted for bioarchaeological researches and international standards and recommendations should be established for this kind of investigation on skeletal remains.

Salivary calcium concentration and periodontal health of young adults in relation to tobacco smoking.

PURPOSE: To evaluate the effect of tobacco smoking and salivary calcium on the periodontal status of young adults. MATERIALS AND METHODS: Plaque index, gingival bleeding on probing, supragingival calculus, DMFT index, salivary flow, pH and salivary calcium in unstimulated salivary samples were recorded in smokers and nonsmokers. RESULTS: There were no significant differences between smokers and nonsmokers with respect to salivary flow (P = 0.08) and calcium level (P = 0.09). Significant correlations (P < 0.05) were found between a higher calcium level and higher probing depth (r = 0.60), higher number of teeth with probing depth of more than 4 mm (r = 0.70), greater clinical attachment level (r = 0.49) and lower number of teeth bleeding on probing (r = -0.50). CONCLUSION: Moderate smoking of tobacco cigarettes in young healthy subjects may not have a significant impact on salivary flow or calcium concentrations in unstimulated saliva, but an association exists between an increased level of salivary calcium and development of periodontal disease.

Physical fitness course in the dental curriculum and prevention of low back pain.

Physical and psychosocial stressors in dental schools are associated with adverse health outcome, including low back pain. The aim of this study was to evaluate the physical fitness course included in a dental school's curriculum with regard to prevention of low back pain. Ninety first-year and sixty-two final-year dental students completed an anonymous questionnaire on physical fitness habits and low back pain. Fifty voluntarily participated in the Åstrand bicycle ergometer test. The questionnaire revealed that 37 percent of the students have weekly physical exercise only during the physical fitness course included in the curriculum and 62.5 percent of the students reported low back pain. Final-year dental students had significantly more low back pain than first-year dental students (r=0.21, χ(2)=7.91, p=0.005). Female students had significantly more low back pain than male students (r=0.28, χ(2)=6.61, p=0.0101). The Åstrand test revealed that students who attended the physical fitness course had significantly better physical fitness (p=0.008) than those who did not. Students who exercised more regularly had significantly less low back pain (r =-0.19, χ(2)=11.89, p<0.01) than those who did not. We conclude that participation in a physical fitness course leads to improved low back health for dental students and may prevent low back pain among final-year dental students.