Impact of the Tobacco Heating System and Cigarette Smoking on the Oral Cavity: A Pilot Study.

Cigarette smoking and the harmful chemicals released during smoking have negative effects on oral health. As a measure of harm reduction, a new alternative tobacco heating system (THS) has been developed. The aim of the study was to analyze and compare the effects of conventional cigarettes and THS on the oral mucosa, the salivary flow rate (SFR), halitosis, and the load of Candida spp. The study included 20 tobacco heating smokers, 20 conventional cigarette smokers, and 20 nonsmokers. The subjects completed questionnaires on medical information, smoking habits, oral lesions, and symptoms. A clinical examination and SFR test were performed on each subject, followed by an organoleptic assessment of halitosis. Mucosal swabs were collected and cult ured to identify Candida spp. Significant differences were found between the smoking groups in relation to halitosis (p < 0.001; ε2 = 0.624), intraoral findings (p < 0.001; ε2 = 0.507), SFR (p < 0.001; ε2 = 0.0331) and dry mouth for subjective complaints (p = 0.021; ε2 = 0.363). The SFR was significantly lower; however, halitosis, the prevalence of intraoral findings, and dry mouth were significantly higher among smokers, but there were no significant differences between THS and conventional smokers. The present study suggests that THS smoking has similar effects on oral tissues, especially the SFR and halitosis, as conventional cigarette smoking.

Association of Masticatory Efficiency and Reduced Number of Antagonistic Contacts Due to Extraction, Changing Dentition or Malocclusion in Children.

BACKGROUND: Tooth extraction, changing dentition and malocclusion can decrease area of occlusal contact and negatively affect masticatory efficiency. Aim of this study was to evaluate difference in masticatory efficiency in association with previously named factors. MATERIALS AND METHODS: In this cross-sectional study masticatory efficiency parameters (number of particles, mean diameter and mean surface of particles) determined with optical scanning method were compared between children with healthy dentition (12 girls, 12 boys, age 3 to 14) and children with lost antagonistic contacts due to tooth extraction, changing dentition and malocclusions (12 girls, 12 boys, age 3 to 14). RESULTS: Number of chewed particles is significantly higher in a group of children with healthy dentition (p < 0.001), and chewed particles' mean diameter and surface are significantly higher in the Group 2 (p < 0.001; p < 0.001). Number of lost occlusal contacts is not in correlation with masticatory efficiency parameters (p= 0.464; p= 0.483; p= 0.489). CONCLUSIONS: Children with lost antagonistic contacts have an impaired masticatory efficiency in comparison to children with complete dentition, but there is no difference regarding the aetiology of contact loss.

Oral Candidal Colonization in Patients with Different Prosthetic Appliances.

Oral infections caused by Candida species are becoming more common, which may be related to an increase in the number of immunologically compromised patients as well as favorable conditions in the oral cavity that often include removable prosthetic appliances. The purpose of this study was to determine the presence of a particular Candida species in patients with PMMA and Cr-Co prosthetic appliances, as well as the salivary flow rate, and oral signs and symptoms. This investigation included a total of 120 subjects with different kinds of removable dentures. A sample of concentrated oral rinse was collected from all subjects in order to detect Candida colonization and identify the Candida species, a quantum of salivation was measured, and subjects were examined clinically. Candida spp. was predominant among the subjects who were denture wearers (p < 0.0001). In all subjects, the most frequently detected species was C.albicans. A statistically significant difference was found between the prevalence of C.albicans (p < 0.001) and C.krusei (p < 0.001) in denture wearers. Subjects with PMMA-based removable prosthetic appliances mostly demonstrated a significant decrease in salivation (p < 0.001), an increase in burning sensations (p < 0.001), and dry mouth (p < 0.001) compared to the subjects who wore partial dentures with Co-Cr metallic frameworks. Red oral lesions were more frequently found among the subjects with partial dentures with Co-Cr metallic frameworks (p < 0.001). Regardless of the material used for the denture, patients must be regularly checked by their dentists in order to prevent the development of oral lesions.

P2Y2 Receptors Mediate Masseter Muscle Mechanical Hypersensitivity in Rats.

PURPOSE: P2Y2 receptors (P2Y2Rs) are among the various receptors that play an important role in nociception. The goal of this research was to investigate possible P2Y2R expression changes in the trigeminal ganglion (TRG) in bilateral masseter muscle (MM) hypersensitivity following unilateral MM inflammation. The impact of unilateral intramasseteric administration of P2Y2R antagonist on bilateral MM hypersensitivity was also explored. MATERIALS AND METHODS: Bilateral MM hypersensitivity was provoked by unilateral intramasseteric injection of complete Freund's adjuvant (CFA). The head withdrawal threshold (HWT) was assessed bilaterally 4 days later. Bilateral TRG and MM isolation were followed, and quantitative real-time polymerase chain reaction (qRT-PCR) and histopathological analysis were carried out on these tissues, respectively. The involvement of P2Y2Rs in nocifensive behavior was evaluated by administering two doses of P2Y2R antagonist AR-C118925 (0.2 or 1 mg/100 µL) in inflamed MM 4 days post-CFA administration. Bilateral HWT was assessed at different time points following antagonist injection. RESULTS: qRT-PCR analysis demonstrated P2Y2R up-regulation in TRG ipsilateral to the site of CFA administration. Compared to the controls, both doses of AR-C118925 injected ipsilateral to the TRG increased the bilateral HWT at 30, 60, 90, and 120 minutes after antagonist administration. CONCLUSION: The findings suggest that P2Y2Rs may affect MM inflammatory hypersensitivity owing to its up-regulation in the TRG in MM inflammatory pain states.

Reproducibility of the Obtained Centric Relation Records in Patients with Disc Displacement with Reduction.

OBJECTIVE: The aim of this study was to investigate reproducibility of the position of centric relation in patients with disc displacement with reduction. MATERIALS AND METHODS: The test group included 30 subjects, diagnosed with disc displacement with reduction in right, left or both joints. The control group included 12 individuals with no signs and symptoms of temporomandibular disorders. Using chin point guidance with a jig, centric relation record was made three times by every participant, in a single session. Left and right condylar position for each centric relation record was determined and recorded using the electronic ultrasonic measuring device. The data were transferred to the computer, processed and analyzed. Condylar distances between centric relation records were measured (anteroposterior, vertical, transversal and linear values), and the data were statistically analyzed using the t and the F tests. RESULTS: No statically significant difference was found between the test and the control groups. Two thirds of study participants demonstrated condylar position of the repeated centric relation recording within the area of 0.3 mm in diameter. For more than 90% of participants that area was within 0.4 mm. CONCLUSIONS: There is no difference in reproducibility of the centric relation between patients with disc displacement with reduction and healthy temporomandibular joint individuals (p>0.05). When doing centric relation record on a patient with disc displacement with reduction there is no need for previous splint therapy and standard precautions are acceptable. The obtained results must be interpreted within the experimental group, and not projected on the other groups of temporomandibular disorders.

The role of P2X3 receptors in bilateral masseter muscle allodynia in rats.

AIM: To determine the relationship between bilateral allodynia induced by masseter inflammation and P2X3 receptor expression changes in trigeminal ganglia (TRG) and the influence of intramasseteric P2X3 antagonist administration on bilateral masseter allodynia. METHODS: To induce bilateral allodynia, rats received a unilateral injection of complete Freund's adjuvant (CFA) into the masseter muscle. Bilateral head withdrawal threshold (HWT) was measured 4 days later. Behavioral measurements were followed by bilateral masseter muscle and TRG dissection. Masseter tissue was evaluated histopathologically and TRG tissue was analyzed for P2X3 receptor mRNA expression by using quantitative real-time polymerase chain reaction (PCR) analysis. To assess the P2X3 receptor involvement in nocifensive behavior, two doses (6 and 60 µg/50 µL) of selective P2X3 antagonist A-317491 were administrated into the inflamed masseter muscle 4 days after the CFA injection. Bilateral HWT was measured at 15-, 30-, 60-, and 120-minute time points. RESULTS: HWT was bilaterally reduced after the CFA injection (P<0.001). Intramasseteric inflammation was confirmed ipsilaterally to the CFA injection. Quantitative real-time PCR analysis demonstrated enhanced P2X3 expression in TRG ipsilaterally to CFA administration (P<0.01). In comparison with controls, the dose of 6 µg of A-317491 significantly increased bilateral HWT at 15-, 30-, and 60-minute time points after the A-317491 administration (P<0.001), whereas the dose of 60 µg of A-317491 was efficient at all time points ipsilaterally (P=0.004) and at 15-, 30-, and 60-minute time points contralaterally (P<0.001). CONCLUSION: Unilateral masseter inflammation can induce bilateral allodynia in rats. The study provided evidence that P2X3 receptors can functionally influence masseter muscle allodynia and suggested that P2X3 receptors expressed in TRG neurons are involved in masseter inflammatory pain conditions.

CO-OCCURRENCE OF CHRONIC HEAD, FACE AND NECK PAIN, AND DEPRESSION IN WAR VETERANS WITH POST-TRAUMATIC STRESS DISORDER.

This study investigated the relationship between chronic head, face and neck pain, and the level of depression in Croatian war veterans with post-traumatic stress disorder (PTSD). The presence of self-reported pain, pain on digital palpation, and pain severity in masticatory and neck muscles, temporomandibular joints and sinuses, as well as the level of depression were assessed in a group of war veterans with PTSD (n=52). Control groups consisted of war veterans without PTSD (n=50) and healthy men that were not engaged in war actions and were free from PTSD (n=50). The number of self-reported pain and number of painful sites were correlated with the level of depression. More self-reported pain and painful sites were recorded in the group of war veterans with PTSD as compared with either war veterans without PTSD or healthy men. Furthermore, PTSD patients mostly suffered from severe depression. There was a statistically significant positive correlation between all investigated pain parameters and level of depression. As the most important finding, the present study demonstrated chronic head, face and neck pain to be related to depression in PTSD patients.

The effect of frequent removable partial denture wearing on alveolar bone resorption.

AIM: To determine the influence of frequent removable partial denture (RPD) wearing on the alveolar bone density changes around the abutment teeth. METHODS: Fifty examinees of both genders, wearing partial dentures, were included in the study. Thirty one of the examinees (62%) were wearing the dentures 24 hours a day, while nineteen (34%) of them were wearing them only during the day. The changes in the bone density around the abutment teeth were determined by the intraoral microdensitometry method. Standard retroalveolar radiographs were performed twice. The first one before the removable partial denture delivery and the second one after a period of three-month denture wearing. A copper step wedge consisting of five steps (0.1-0.5 mm) was attached to the radiograph in order to calibrate it. Seven points, regions of interest (ROI) close to the root of the abutment tooth, all ten pixels in size, were selected on each radiograph. Grey areas in the regions of interest were measured and converted into the copper step wedge thickness equivalents in order to estimate the change in the alveolar bone density and measure the difference in alveolar bone density between two radiographs. RESULTS: The results indicated that there is not any statistically relevant change (t-value less than 2,011; t(49,0.05) / F less than 4,0426; F0.05(1,48)) in the alveolar bone density depending on the frequency of removable partial denture wearing. CONCLUSION: The frequency of removable partial denture wearing does not cause any changes in the alveolar bone density around the abutment teeth in the period of three-month denture wearing.

TRPV1 channel-mediated bilateral allodynia induced by unilateral masseter muscle inflammation in rats.

Pain in masticatory muscles is among the most prominent symptoms of temperomandibular disorders (TMDs) that have diverse and complex etiology. A common complaint of TMD is that unilateral pain of craniofacial muscle can cause a widespread of bilateral pain sensation, although the underlying mechanism remains unknown. To investigate whether unilateral inflammation of masseter muscle can cause a bilateral allodynia, we generated masseter muscle inflammation induced by unilateral injection of complete Freund's adjuvant (CFA) in rats, and measured the bilateral head withdrawal threshold at different time points using a von Frey anesthesiometer. After behavioral assessment, both right and left trigeminal ganglia (TRG) were dissected and examined for histopathology and transient receptor potential vanilloid 1 (TRPV1) mRNA expression using quantitative real-time PCR analysis. A significant increase in TRPV1 mRNA expression occurred in TRG ipsilateral to CFA injected masseter muscle, whereas no significant alteration in TRPV1 occurred in the contralateral TRG. Interestingly, central injection of TRPV1 antagonist 5-iodoresiniferatoxin into the hippocampus significantly attenuated the head withdrawal response of both CFA injected and non-CFA injected contralateral masseter muscle. Our findings show that unilateral inflammation of masseter muscle is capable of inducing bilateral allodynia in rats. Upregulation of TRPV1 at the TRG level is due to nociception caused by inflammation, whereas contralateral nocifensive behavior in masticatory muscle nociception is likely mediated by central TRPV1, pointing to the involvement of altered information processing in higher centers.

Alterations in the masseter muscle and plasma IL-6 level following experimentally induced occlusal interference and chronic stress--a study in rats.

This study was undertaken to examine the alteration of masseter and plasma interleukin-6 after inducing occlusal interference and chronic stress. Male Wistar rats were submitted to chronic stress procedure, exposed to occlusal interference, or exposed to both mentioned procedures. Whole blood and masseter tissue were collected to determine interleukin-6 level, measured by means of ELISA. Masseter pain was evaluated using the orofacial formalin test. Masseter interleukin-6 level was significantly higher in animals submitted to combination of occlusal interference and chronic stress than in the control group (p<0.05). There was positive and significant correlation between pain response and masseter interleukin-6 level (r=0.5741; p<0.0003). No significant differences in plasma interleukin-6 level were found between groups (p>0.05), as well as no correlation with pain (p>0.05). Combination of occlusal interference and chronic stress leads to strong local reaction characterized by high levels of masseter interleukine-6. High concentrations of muscle interleukin-6 and its correlation with pain point to inflammatory background of masticatory muscle pain.

Influences of age and maxillary anterior teeth status on patient's satisfaction with dental appearance and tooth colour.

OBJECTIVES: To study the impact of age, gender, tooth colour and maxillary anterior teeth status on patient's satisfaction with their dental appearance. MATERIAL AND METHODS: A total of 259 Caucasian subjects participated in the study (119 men, mean age 56 years; 140 women, mean age 61 years) divided into three age groups (young <35 age; middle aged 35-54 age; old ≥55 age). Their maxillary anterior teeth status was classified into three groups: (1) natural teeth (NTG) group; (2) composite filling group (CFG) and (3) porcelain-fused-to-metal fixed prosthodontic restoration group (FPDG). The participants judged appearance and tooth colour using a scale with three categories: completely dissatisfied, moderately dissatisfied and completely satisfied. RESULTS: Almost half of the participants were completely satisfied with their dental appearance and tooth colour. Half of the 'young' and 'middle-aged' participants with natural maxillary anterior teeth were completely satisfied and half of the 'old' participants were moderately satisfied with their dental appearance and tooth colour. The majority of participants with composite restorations (45-51%) were moderately satisfied with their dental appearance, one-third of 'young' and 'middle-aged' participants were moderately satisfied or dissatisfied with their tooth colour and more than 70% of older participants were dissatisfied with their tooth colour (p > 0.05). CONCLUSIONS: Satisfaction with the appearance of the maxillary anterior teeth differed both between individuals of different age and different dental status.

Masticatory muscle and temporomandibular joint pain in Croatian war veterans with posttraumatic stress disorder.

The aim of this study was to investigate the prevalence and intensity of masticatory muscle and temporomandibular joint (TMJ) pain in Croatian war veterans with posttraumatic stress disorder (PTSD). The examined group consisted of 100 Croatian war veterans, in whom PTSD had previously been diagnosed. Patients were compared with 92 subjects who had not taken part in the war and in whom PTSD was excluded by psychiatric examination. The clinical examination consisted of palpation of the masticatory muscles, the prominent neck musculature, and TMJ. The examination technique used and the definition of items were previously tested for reliability and validity. 93% of the subjects with PTSD had masticatory muscle tenderness compared to 45.65% of the subjects in the control group (chi2 = 51.46, p < 0.0001). The most frequent painful location in the subjects with PTSD was the left lateral pterygoid site in 88%, and in subjects of the control group the right lateral pterygoid site in 28.26% of cases. The most painful location in the PTSD group was the left lateral pterygoid site in 72%, and in the control group the left posterior digastric in 4.35% of cases. 58% of the subjects with PTSD had TMJ tenderness compared to 3.26% of subjects in the control group (chi2 = 66.23, p < 0.0001). The most frequent painful location of TMJ in both groups was the left posterior capsule; in the PTSD group 38% and in subjects in the control group 2.17% of cases. The most painful location was the left posterior capsule in 28% of subjects with PTSD, while not one subject in the control group reported severe painful sensitivity. The very high frequency and intensity of pain in subjects with PTSD confirms the effect of stress on muscle and joint sensitivity, i.e. perception of pain.

Influence of chronic stress and oclusal interference on masseter muscle pain in rat.

This study aimed to investigate the individual effects of chronic stress and occlusal interference, as well as their combined influence on masseter muscle pain. Experiments were performed on 28 male Wistar rats. Animals were submitted to chronic stress procedure, exposed to occlusal interference, or exposed to both mantioned procedures. At the end of the procedure animals were submitted to orofacial formalin test, and nociceptive behavioral response was evaluated. Statisticaly significant difference of nociceptive behavioral response in chronicaly stressed rats and in the animals with occlusal interference in comparation to the control group were not obtained (p > 0.05). In contrast, nociceptive behavioral response was significantly increased in rats submitted to both of experimental procedures (p < 0.01). These findings suggest that only combination of occlusal interference and chronic stress influence masseter muscle pain.

Changes of alveolar bone density around the abutment teeth in patients wearing removable partial dentures depending on Kennedy classification.

The aim was to study the influence of Kennedy classification on alveolar bone density changes around the abutment teeth of removable partial denture (RPD) clasp and rests. A total of 50 examinees of both gender wearing RPDs were included in the study. Changes of bone density around the abutment teeth were determined by an intraoral microdensitometry method. Standard retroalveolar radiographs were obtained twice: the first one at the RPD delivery and the second one after a period of 3 month of denture wearing. The copper stepwedge consisting of 5 steps (0.1-0.1 mm) was attached to the radiograph prior to exposure in order to calibrate it. Seven regions of interest (ROI) in different position close to the root of the abutment tooth were selected on each radiograph, all 10 pixels in size. Grey levels of each ROI were measured and were converted into equivalents of the copper stepwedge thickness using the third degree polynomial in order to compare the difference of bone density between the two radiographs. The results indicated that Kennedy classification had no significant influence on the change of bone density in RPD patients during first 3 month of RPD wearing (ANOVA: p > 0.05).