Evaluation of pulpal blood flow during orthodontic space closure: Prospective clinical trial.

INTRODUCTION: Orthodontic tooth movement (OTM) is a biological process that can affect the vascularization of the dental pulp. The forces exerted on the teeth may increase periapical pressure that could compress the arterioles, which in turn affects pulpal blood flow (PBF). The study aimed to investigate how OTM affects PBF during orthodontic space closure. METHODS: A total of 22 adolescent participants who required orthodontic space closure in mandibular posterior sectors were enrolled in a prospective clinical study. The same sliding mechanics, wires, and active elements were used. Patients were observed before OTM, after leveling before space closure, and at the 4th, 7th, 21st, and 28th during active space closure. PBF was measured with laser Doppler (LD) flowmetry. Dental models were obtained with an intraoral scanner. RESULTS: The LD flow values decreased significantly during the observation period (2-way repeated measures analysis of variance, P <0.001). There was a significant difference in LD flow between tooth categories (2-way repeated measures analysis of variance, P <0.001). During space closure, the most pronounced LD flow reduction was observed in single-rooted teeth closest to the residual space. A higher speed of OTM was associated with a greater decrease in LD flow on day 4 of OTM (Pearson correlation, P = 0.0299). CONCLUSIONS: Orthodontic space closure reduced PBF; it was lowest in the early stages of space closure and showed a tendency to increase during the first month. Anterior teeth closer to the interdental space that experiences more OTM and teeth that move faster during initial OTM had a higher risk of reduced blood flow.

Dental Pulp Vascular Response to Early Stages of Caries.

OBJECTIVES: During caries progression, dental pulp is increasingly pathologically affected. Since the accurate assessment of pulp is of vital importance in clinical decision-making, this study aimed to evaluate pulpal condition in the early stages of caries via laser Doppler (LD) flowmetry and histologic analysis and determine their agreement. METHODS: Fourteen patients with severe dental crowding were included. Prior to extractions and orthodontic treatment, dental pulp condition of 52 premolars was evaluated via LD flowmetry. Teeth were assessed for the presence of caries and lesions were graded according to the International Caries Detection and Assessment System (ICDAS). After extractions, teeth were split and histologically stained for endothelial cells with anti-von Willebrand factor and Movat pentachrome for collagen. Volume densities of vessels (Vvasc) and collagen were calculated. RESULTS: There was a significant negative correlation between LD flow and Vvasc of the dental pulp with ICDAS grade. Pulpal LD flow and Vvasc in teeth with the initial lesion were increased, decreasing with progressing stages of caries. A significant positive correlation between the the pulpal LD flow and Vvasc, and a negative correlation of LD flow with collagen fibre density were noted. CONCLUSIONS: Caries affects the physiology of the dental pulp, initially with increasing vascularity, and decreasing vascularity at later stges of caries progression. Collagen contents increase with grades of ICDAS. LD flow shows good agreement with the histologic constitution of the dental pulp. Use of clinical measurements of pulpal LD flow could provide a good noninvasive indication of pulpal vascular state and its health.

Assessment of dental pulp response to carries via MR T2mapping and histological analysis.

OBJECTIVES: The aim of our study was to assess the correlation between T2 relaxation times and their variability with the histopathological results of the same teeth in relation to caries progression. MATERIALS AND METHODS: 52 extracted permanent premolars were included in the study. Prior to extractions, patients underwent magnetic resonance imaging (MRI) scanning and teeth were evaluated using ICDAS classification. Pulps of extracted teeth were histologically analysed. RESULTS: MRI T2 relaxation times (ms) were 111,9 ± 11.2 for ICDAS 0, 132.3 ± 18.5* for ICDAS 1, 124.6 ± 14.8 for ICDAS 2 and 112. 6 ± 18.2 for ICDAS 3 group (p = 0,013). A positive correlation was observed between MRI T2 relaxation times and macrophage and T lymphocyte density in healthy teeth. There was a positive correlation between vascular density and T2 relaxation times of dental pulp in teeth with ICDAS score 1. A negative correlation was found between T2 relaxation times and macrophage density. There was a positive correlation between T2 relaxation time variability and macrophage and T lymphocyte density in teeth with ICDAS score 2. In teeth with ICDAS score 3, a positive correlation between T2 relaxation times and T2 relaxation time variability and lymphocyte B density was found. CONCLUSION: The results of our study confirm the applicability of MRI in evaluation of the true condition of the pulp tissue. CLINICAL RELEVANCE: With the high correlation to histological validation, MRI method serves as a promising imaging implement in the field of general dentistry and endodontics.

Effect of orthodontic space closure on dental pulp sensitivity. Prospective clinical trial.

BACKGROUND: Orthodontic tooth movement (OTM) is a biological process that can influence the function of the pulp, including its innervation. The excitability of the nerve fibres of the pulp may be altered by forces exerted on the nerve fibres or by reduced blood flow to the pulp. The aim of this clinical study was to evaluate the sensitivity of the dental pulp during levelling and during the phase of space closure, to assess the role of certain controlled risk factors. METHODS: Twenty-two adolescent participants requiring orthodontic space closure in transcanine sector were enrolled in a prospective clinical study. Patients were observed before OTM, after levelling and 1 month during active space closure. The sensitivity threshold of the pulp was measured using the electric pulp test (EPT). Dental models were obtained using an intraoral scanner, allowing measurement of interdental distances and calculation of OTM speed. The teeth were categorized according to position and tooth type. RESULTS: The EPT values increased significantly during orthodontic treatment (one-way RM-ANOVA, P = .014). There was a significant difference in EPT values between the tooth categories. Teeth with a single root adjacent to the residual space had the highest EPT thresholds (two-way RM-ANOVA, P < .001; Holm-Sidak, P < .05). CONCLUSIONS: OTM reduced pulpal sensitivity. Pulpal sensitivity during active space closure was similar to sensitivity during the levelling phase. The pulpal sensitivity of molars was less affected by OTM than that of single-rooted teeth, while teeth closer to the gap had a significantly higher pulpal sensitivity threshold during active OTM.

The effects of normobaric and hyperbaric oxygenation on MRI signal intensities in T1 -weighted, T2 -weighted and FLAIR images in human brain.

BACKGROUND: Dissolved oxygen has known paramagnetic effects in magnetic resonance imaging (MRI). The aim of this study was to compare the effects of normobaric oxygenation (NBO) and hyperbaric oxygenation (HBO) on human brain MRI signal intensities. PATIENTS AND METHODS: Baseline brain MRI was performed in 17 healthy subjects (mean age 27.8 ± 3.2). MRI was repeated after exposure to the NBO and HBO at different time points (0 min, 25 min, 50 min). Signal intensities in T 1-weighted, T 2-weighted images and fluid attenuated inversion recovery (FLAIR) signal intensities of several intracranial structures were compared between NBO and HBO. RESULTS: Increased T 1-weighted signal intensities were observed in white and deep grey brain matter, cerebrospinal fluid (CSF), venous blood and vitreous body after exposure to NBO as well as to HBO compared to baseline (Dunnett's test, p < 0.05) without significant differences between both protocols. There was also no significant difference in T 2-weighted signal intensities between NBO and HBO. FLAIR signal intensities were increased only in the vitreous body after NBO and HBO and FLAIR signal of caudate nucleus was decreased after NBO (Dunnett's test, p < 0.05). The statistically significant differences in FLAIR signal intensities were found between NBO and HBO (paired t-test, p < 0.05) in most observed brain structures (paired t-test, p < 0.05). CONCLUSIONS: Our results show that NBO and HBO alters signal intensities T 1-weighted and FLAIR images of human brain. The differences between NBO and HBO are most pronounced in FLAIR imaging.

Early isolated subarachnoid hemorrhage versus hemorrhagic infarction in cerebral venous thrombosis.

BACKGROUND: Cerebral venous thrombosis (CVT) is a rare cerebral vascular disease, the presentation of which is highly variable clinically and radiologically. A recent study demonstrated that isolated subarachnoid hemorrhage (iSAH) in CVT is not as rare as thought previously and may have a good prognostic significance. Hemorrhagic venous infarction, however, is an indicator of an unfavorable outcome. We therefore hypothesized that patients who initially suffered iSAH would have a better clinical outcome than those who suffered hemorrhagic cerebral infarction. PATIENTS AND METHODS: We selected patients hospitalized due to CVT, who presented either with isolated SAH or cerebral hemorrhagic infarction at admission or during the following 24 hours: 23 (10 men) aged 22-73 years. The data were extracted from hospital admission records, our computer data system, and the hospital radiological database. RESULTS: The iSAH group consisted of 8 (6 men) aged 49.3 ± 16.2 and the hemorrhagic infarction group included 15 (4 men) aged 47.9 ± 16.8. Despite having a significantly greater number of thrombosed venous sinuses/deep veins (Mann-Whitney Rank Sum Test, p = 0.002), the isolated SAH group had a significantly better outcome on its modified Rankin Score (mRs) than the hemorrhagic infarction group (Mann-Whitney Rank Sum Test, p = 0.026). Additional variables of significant impact were edema formation (p = 0.004) and sulcal obliteration (p = 0.014). CONCLUSIONS: The patients who suffer iSAH initially had a significantly better outcome prognosis than the hemorrhagic infarction patients, despite the greater number of thrombosed sinuses/veins in the iSAH group. A possible explanation might include patent superficial cerebral communicating veins.

Heart Rate Variability in Huntington Disease: A Long-Term Longitudinal Study.

INTRODUCTION: The aim of the study was to follow tonic and phasic autonomic nervous activity in Huntington disease (HD) mutation carriers and patients. METHODS: Evaluation of motor functions and total functional capacity was performed in 30 HD mutation carriers or patients at the beginning and in 22 subjects after 8-10 years. Continuous arterial blood pressure, heart rate (HR), and ECG at rest were measured, and HR variability analysis was performed in four different ways. A group of matched controls was also evaluated. RESULTS: Eighteen subjects were assorted in 3 groups: 6 HD mutation carriers without motor symptoms (PHD) who remained so (PHD-PHD); 6 early symptomatic patients (EHD) who remained so (EHD-EHD); and 6 early symptomatic patients who deteriorated to a late symptomatic (LHD) (EHD-LHD). At the beginning, sympathetic tonic activity in PHD was elevated, according to mean arterial pressure (99 ± 10.6 mm Hg) higher than in controls (85 ± 8.7 mm Hg) and EHD (82 ± 9.9 mm Hg) (Dunnett's test, p < 0.05) and higher HR (78 ± 16 beats/min) than after 8-10 years (64 ± 11.3 beats/min) (paired t test, p < 0.05). There was also a decreased phasic sympathetic activity in EHD patients compared controls at the beginning (219 ± 106 vs. 664 ± 466 s2/Hz) and after 8-10 years (182 ± 136 vs. 1,012 ± 1,369 s2/Hz) (Dunnett's test, p < 0.05). In patients who deteriorated from EHD to LHD, there was a drop in phasic parasympathetic activity from 887 ± 433 to 230 ± 235 s2/Hz (paired t test, p < 0.05). CONCLUSIONS: Our long-term observational study provides important information on the timeline of ANS activity in HD progress. There was a temporary increase in cardiac and vascular sympathetic activity in PHD subjects. The normalization of HR in PHD subjects might indicate the approach of an outbreak of clinical disease phase.

Comparison of the vitality tests used in the dental clinical practice and histological analysis of the dental pulp.

In dentistry, indirect diagnostic methods such as electrical sensibility testing and pulse oximetry are used to assess the status of the pulp. Our study aimed to determine the correlation between hemoglobin oxygen saturation and vascular volume density (Vvasc). We also wanted to examine an electrical sensibility test and the volume density of myelinated nerve fibers (Vnerv). Twenty-six intact permanent premolars were included in the study. For histological analysis, the pulp tissue was stained with hematoxylin-eosin and immunohistochemically for von Willebrand factor and S100 to detect blood vessels and myelinated nerve fibers, respectively. The stereological analysis was used to determine the Vvasc and Vnerv. Statistical analysis was done using the Pearson correlation test and Welch's ANOVA test. Histological analysis showed that the pulp tissue was strongly vascularized and innervated. A significant positive correlation was found between Vvasc and hemoglobin oxygen saturation levels (p=0.030). A significant negative correlation was found between Vnerv and the lowest electrical voltage that patient felt (p=0.033). According to the maturity of the dental apex, teeth were divided into a group with open (N=6, OA group) and closed apex (N=20, CA group). We found that pulps in the CA group had higher Vnerv than the OA group (p=0.037). In contrast, there were no significant differences in Vvasc of the pulp tissue (p=0.059), oxygen saturation (p=0.907), or electrical voltage (p=0.113) between both groups. We can conclude that the measurement of pulse oximetry and electrical sensibility test reflect the morphology of healthy pulp tissue independently of the maturity of the dental apex.

Assessment of hyperbaric oxygenation treatment response in parotid glands by T2 mapping following radiotherapy for head and neck tumours.

BACKGROUND: The study was designed to evaluate the influence of hyperbaric oxygenation therapy (HBOT) on the parotid gland in patients following radiotherapy for head and neck tumours. PATIENTS AND METHODS: HBOT response was monitored by 3T magnetic resonance imaging (MRI) using T2 mapping and subsequent measurement of mean T2 and T2 variability as well as by salivary tests (salivary flow, buffer capacity, and pH). Eighteen patients previously treated with irradiation doses between 50 and 80 Gy as well as 18 healthy gender and age matched controls were enrolled. MRI was performed prior to HBOT (40.2 ± 20 months after radiotherapy) and after 20 daily HBOT at 2.5 ATA (absolute atmosphere). Each HBOT consisted of breathing 100% oxygen for 90 minutes. RESULTS: Significant differences in mean T2 prior to HBOT were observed between the ipsilateral irradiated (121 ± 20 ms), contralateral parotids (107 ± 21) and control group (96 ± 12 ms). A positive correlation in patients between T2 variability and irradiation dose was detected in contralateral parotids before HBOT (R = 0.489, p = 0.0287). In addition, negative correlations were observed between mean T2 in the ipsilateral as well as the contralateral gland and salivary flow before and after HBOT. Negative correlations between mean T2, T2 variability and pH of unstimulated saliva were also observed in the sides of parotid before and after HBOT. CONCLUSIONS: The study confirmed that T2 mapping had a potential for monitoring the differences between irradiated and normal parotid glands. It could also be useful in the assessment of the glandular tissue response to HBOT.

Effects of low-level light therapy on xerostomia related to hyposalivation: a systematic review and meta-analysis of clinical trials.

Hyposalivation is a condition represented by a reduced salivary flow and may include symptoms such as mouth dryness (xerostomia), loss of taste, pain, dysphagia, and dysphonia, all of which greatly affect an individual's quality of life.The aim of the present study was to systematically review the effects of low-level light therapy irradiation (photobiomodulation) on salivary gland function in patients with hyposalivation.The main question of the systematic review was: "Does low-level light irradiation therapy of the salivary glands affect salivary flow rate or indicators of salivary function (ion and protein concentrations) in patients with xerostomia or hyposalivation?" The question was based on the PICO (participant, intervention, control, outcome) principle and followed the PRISMA guidelines. Databases were explored and papers published between the years 1997 and 2020 were reviewed for the following Mesh-term keywords and their corresponding entry terms in different combinations: "Low-level light therapy," "Xerostomia," "Saliva," "Salivary glands," "Salivation."The initial sample consisted of 220 articles. Of those, 47 articles were used for full-text analysis and 18 were used for a systematic review, 14 were used in meta-analysis. According to their individual quality, most articles were classified as high quality of evidence according to the GRADE score. Meta-analysis of the evidence observed increase of unstimulated salivary flow 0.51 SMD compared to placebo (95% CI: 0.16-0.86), I2 = 50%, p = 0.005.The findings of our review revealed evidence of a beneficial effect of photobiomodulation therapy on salivary gland function. The therapy alleviates xerostomia and hyposalivation. However, these effects are reported short term only and did not induce lasting effects of photobiomodulation therapy on patients' quality of life.