The use of laser Doppler flowmetry to evaluate oral soft tissue blood flow in humans: A review

Exploring the efficacy of laser speckle contrast imaging in the stratified diagnosis of rosacea: a quantitative analysis of facial blood flow dynamics across varied regions

Background

Rosacea has a high incidence, significantly impacts quality of life, and lacks sufficient diagnostic techniques. This study aimed to investigate the feasibility of laser speckle contrast imaging (LSCI) for measuring facial blood perfusion in patients with rosacea and to identify differences in blood flow among various facial regions associated with different rosacea subtypes.

Methods

From June to December 2023, 45 patients were recruited, with 9 excluded, leaving 36 subjects: 12 with erythematotelangiectatic rosacea (ETR), 12 with papulopustular rosacea (PPR), and 12 healthy controls. The Think View multispectral imaging analyzer assessed inflammation via gray reading values across the full face and five facial areas: forehead, nose, cheeks, and chin. LSCI measured and analyzed blood perfusion in the same areas. Plasma biomarkers interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α) were tested in different groups.

Results

Both ETR and PPR groups showed increased average blood perfusion and facial inflammation intensity by gray values compared to controls, with statistically significant differences. Average blood perfusion of ETR and PPR groups showed increased values in the forehead, cheeks, and nose, compared to controls, and the values in the cheeks were statistically different between ETR and PPR. The facial inflammation intensity of the ETR group showed increased values in the forehead and cheeks, and the PPR group showed increased gray values in the forehead, cheeks, nose, and chin compared to controls, and the values for the cheeks, nose, and chin were statistically significantly different between ETR and PPR. Plasma biomarkers IL-6, IL-1β, and TNF-α were significantly elevated in both ETR and PPR groups compared to controls.

Conclusion

LSCI is a valuable, non-invasive tool for assessing blood flow dynamics in rosacea, providing a data foundation for clinical research. Different rosacea subtypes exhibit distinct lesion distribution and blood flow patterns, and both ETR and PPR could affect all facial areas, particularly the cheeks in ETR and the forehead, nose, and chin in PPR.

Investigation on the influence of the skin tone on hyperspectral imaging for free flap surgery

Hyperspectral imaging (HSI) is a new emerging modality useful for the noncontact assessment of free flap perfusion. This measurement technique relies on the optical properties within the tissue. Since the optical properties of hemoglobin (Hb) and melanin overlap, the results of the perfusion assessment and other tissue-specific parameters are likely to be distorted by the melanin, especially at higher melanin concentrations. Many spectroscopic devices have been shown to struggle with a melanin related bias, which results in a clinical need to improve non-invasive perfusion assessment, especially for a more pigmented population. This study investigated the influence of skin tones on tissue indices measurements using HSI. In addition, other factors that might affect HSI, such as age, body mass index (BMI), sex or smoking habits, were also considered. Therefore, a prospective feasibility study was conducted, including 101 volunteers from whom tissue indices measurements were performed on 16 different body sites. Skin tone classification was performed using the Fitzpatrick skin type classification questionnaire, and the individual typology angle (ITA) acquired from the RGB images was calculated simultaneously with the measurements. Tissue indices provided by the used HSI-device were correlated to the possible influencing factors. The results show that a dark skin tone and, therefore, higher levels of pigmentation influence the HSI-derived tissue indices. In addition, possible physiological factors influencing the HSI-measurements were found. In conclusion, the HSI-based tissue indices can be used for perfusion assessment for people with lighter skin tone levels but show limitations in people with darker skin tones. Furthermore, it could be used for a more individual perfusion assessment if different physiological influencing factors are respected.

Comparison of clinical outcomes between transthoracic echocardiography- and X-ray-guided left bundle branch pacing for bradycardia: A randomized controlled trial

INTRODUCTION

Left bundle branch pacing (LBBP) is a physiological pacing modality. However, the long procedure and fluoroscopy time of LBBP is still a problem. This study aims to compare the clinical outcomes between transthoracic echocardiography (TTE)- and X-ray-guided LBBP.

METHODS

This is a single-center, prospective, randomized controlled study. Consecutive patients who underwent LBBP in our team from June 2022 to November 2022 were enrolled. Procedure and fluoroscopy time, pacing parameters, electrophysiological and echocardiographic characteristics, as well as complications were recorded at implantation and during follow-up.

RESULTS

In this study, 60 patients were enrolled and divided into two groups: 30 patients were allocated to the X-ray group and the remaining 30 to the TTE group. There was no significant difference in the success rate between the two groups (86.7% vs. 76.7%, p = .317). The procedure time of TTE group was comparable to that of the X-ray group (9.0 vs. 12.0 min, p = .063). However, the fluoroscopy time in the TTE group was significantly lower than that of the X-ray group (2.5 vs. 5.0 min, p = .002). There were no statistically significant differences in pacing parameters, electrophysiological and echocardiographic characteristics, or complications between the two groups at implantation and during follow-up.

CONCLUSION

TTE-guided LBBP is a feasible and safe method. Compared with X-ray, TTE showed a comparable success rate and procedure time, but it could significantly reduce the fluoroscopy time of LBBP.

Reproducibility of Laser Doppler Flowmetry in gingival microcirculation. A study on six different protocols

OBJECTIVES

Laser Doppler Flowmetry (LDF) is a non-invasive technique for the assessment of tissue blood flow, but increased reproducibility would facilitate longitudinal studies. The aim of the study was to assess the interday reproducibility of Laser Doppler Flowmetry (LDF) at rest, at elevated local temperatures, and with the use of the vasodilator Methyl Nicotinate (MN) in six interconnected protocols for the measurement of the blood supply to the microvascular bed of the gingiva.

METHODS

Ten healthy volunteers were included. Interweek LDF measurements with custom-made acrylic splints were performed. Six protocols were applied in separate regions of interest (ROI): 1; basal LDF, 2; LDF with thermoprobe 42 °C, 3; LDF with thermoprobe 45 °C, 4; LDF with thermoprobe 42 °C and MN, 5; LDF with thermoprobe 45 °C and MN and 6; LDF with MN.

RESULTS

Intra-individual reproducibility was assessed by the within-subject coefficient of variation (wCV) and the intraclass correlation coefficient (ICC). Basal LDF measurements demonstrated high reproducibility with wCV 11.1 in 2 min and 10.3 in 5 min. ICC was 0.9 and 0.92. wCV after heat and MN was 4.9-10.3 and ICC 0.82-0.93. The topically applied MN yielded increased blood flow.

CONCLUSION

This is the first study evaluating the reproducibility of basal LDF compared to single or multiple vasodilatory stimuli in gingiva. Multiple collector fibers probe and stabilizing acrylic splints are recommended. Vasodilatory stimulation showed a tendency toward higher reproducibility. Furthermore, MN yields vasodilation in gingiva.

Research on the classification of early-stage brain edema by combining intrinsic optical signal imaging and laser speckle contrast imaging

The early detection and pathological classification of brain edema are very important for symptomatic treatment. The dual-optical imaging system (DOIS) consists of intrinsic optical signal imaging (IOSI) and laser speckle contrast imaging (LSCI), which can acquire cerebral hemodynamic parameters of mice in real-time, including changes of oxygenated hemoglobin concentration ( Δ C HbO 2 ), deoxyhemoglobin concentration (ΔCHbR) and relative cerebral blood flow (rCBF) within the field of view. The slope sum of Δ C HbO 2 , ΔCHbR and rCBF was proposed to classify vasogenic edema (VE) and cytotoxic edema (CE). The slope sum values in the VE and CE group remain statistically different and the classification results provide higher accuracy of more than 93% for early brain edema detection. In conclusion, the differences of hemodynamic parameters between VE and CE in the early stage were revealed and the method helps in the classification of early brain edema.

[Laser Doppler flowmetry in the diagnosis of chronic mixed blepharitis]

Chronic mixed blepharitis accounts for 51.7% of all ophthalmic diseases. The use of laser Doppler flowmetry (LDF) in the diagnosis of this disease can help establish the initial manifestations of the inflammatory process in the eyelids, which is important for the prevention of possible complications - dry eye disease.

PURPOSE

This study was conducted to determine the sensitivity and specificity of the LDF method in the diagnosis of chronic mixed blepharitis based on the study of microcirculatory changes in the eyelid skin.

MATERIAL AND METHODS

The study included 23 patients with chronic mixed blepharitis (mean age 67±5.8 years) and 18 healthy volunteers (mean age 63±1.1 years). LDF was performed using the LAZMA MC-1 device. ROC analysis was used to determine sensitivity and specificity.

RESULTS

A typical disturbance of the eyelid skin microcirculation was revealed in chronic mixed blepharitis - ischemia - with inhibition of the intensity of the functioning of blood flow regulatory systems and moderate activation of the lymph flow. The sensitivity and specificity of the coefficient of variation (reflecting the vasomotor activity of microvessels) of blood flow was 71.43 and 71.43%, lymph flow - 65.71 and 80.00%; myogenic rhythms of blood flow - 83.33 and 85.71%, lymph flow - 66.67 and 71.43%; neurogenic rhythms of blood flow - 75.00 and 78.57%, lymph flow - 91.67 and 78.57%, respectively.

CONCLUSION

Laser Doppler flowmetry of the eyelid skin in combination with clinical, functional and instrumental research methods helped reveal with high sensitivity and specificity the eyelid damage in chronic mixed blepharitis. This method allows assessment of the condition of the eyelids in individuals without diseases of the anterior segment of the eye.

Evaluation of the effects of platelet-rich fibrin and diode laser on gingival blood perfusion and early bone healing of the extraction socket: a randomized controlled clinical trial

Evaluation and comparison of the effect of platelet-rich fibrin (PRF), diode laser, and combination of PRF and diode laser on gingival blood perfusion and early bone formation of the extraction socket. Forty maxillary premolar sockets were randomized to four groups: control group, PRF group, diode laser group, and PRF + diode laser group. Gingival blood perfusion was measured at preoperative and postoperative 1, 3, 7, and 30 days. Fractal dimension analysis was performed immediately after the procedure and in the postoperative first month. Gingival perfusions significantly increased during 1 week compared to baseline for all groups with a mean of -4.43 ± 3.20, -5.99 ± 3.68, -5.45 ± 3.01, and -4.78 ± 2.82 respectively, and were at baseline 1 month later. There were no statistically significant differences between the groups at any time point. Although the increase of fractal dimension was higher in the PRF or diode laser group than in the control group with a mean of 0.085 ± 0.05, 0.100 ± 0.04, and 0.072 ± 0.04 respectively, no statistically significant differences were detected. Fractal dimension was significantly greater in PRF + diode laser group than in the control group with a mean of 0.138 ± 0.05 (p = 0.04). PRF, diode laser, and PRF + diode laser did not significantly affect the gingival perfusion, and the combined application of PRF and diode laser had positive effects on early bone regeneration in the extraction socket. PRF, diode laser, and PRF + diode laser provide better tissue healing of the extraction socket.

Case-control study analyzing the relationship between oral microcirculation and oral mucositis and pain in patients under antineoplastic therapy

The study aimed to evaluate the relation between microcirculation of the genian region using laser Doppler flowmetry and oral mucositis (OM) and pain in individuals undergoing antineoplastic therapy. A case-control clinical study was conducted with the participants divided into three groups: chemotherapy (CTG), radiation therapy and chemotherapy group (RCTG), and control group (CG). Pain was assessed by visual analog scale; OM was classified by oral mucositis assessment and WHO scales. The blood flow was assessed by laser Doppler flowmetry. Kruskal-Wallis statistical test, Friedman test, and Spearman test were used for statistical analysis of this study. CTG (7 individuals/25.93%) showed the worst manifestations of OM between 2nd and 4th evaluations (OM-WHO: T2, p = 0.006; T3, p = 0.006; T4, p = 0.003; OM-OMAS: T2, p = 0.004; T3, p = 0.000; T4, p = 0.011), and increased blood flow over time, with the exception of the 3rd evaluation (p = 0.138). The RCTG (9 individuals/33.33%) showed the worst manifestations of oral mucositis on the 4th week (OM-WHO and OM-OMAS: p = 0.000) with a decrease in blood flow (p = 0.068). The decreased blood flow is associated with greater severity of oral mucositis and greater pain intensity.

Postoperative free flap monitoring in reconstructive surgery-man or machine?

Free tissue transfer is widely used for the reconstruction of complex tissue defects. The survival of free flaps depends on the patency and integrity of the microvascular anastomosis. Accordingly, the early detection of vascular comprise and prompt intervention are indispensable to increase flap survival rates. Such monitoring strategies are commonly integrated into the perioperative algorithm, with clinical examination still being considered the gold standard for routine free flap monitoring. Despite its widespread acceptance as state of the art, the clinical examination also has its pitfalls, such as the limited applicability in buried flaps and the risk of poor interrater agreement due to inconsistent flap (failure) appearances. To compensate for these shortcomings, a plethora of alternative monitoring tools have been proposed in recent years, each of them with inherent strengths and limitations. Given the ongoing demographic change, the number of older patients requiring free flap reconstruction, e.g., after cancer resection, is rising. Yet, age-related morphologic changes may complicate the free flap evaluation in elderly patients and delay the prompt detection of clinical signs of flap compromise. In this review, we provide an overview of currently available and employed methods for free flap monitoring, with a special focus on elderly patients and how senescence may impact standard free flap monitoring strategies.

The Effect of Changing the Toothbrush on the Marginal Gingiva Microcirculation in the Adolescent Population—A Laser Doppler Flowmetry Assessment

It is well-known that proper tooth brushing has the effect of stimulating microcirculation in a healthy gingiva. The aim of this study was to evaluate the microcirculation dynamics at the level of healthy marginal gingiva in adolescents after changing their toothbrush. Three evaluation instruments were employed to assess and quantify the effects on the marginal gingiva: the periodontal probing depth (PD), gingival index (GI) and laser Doppler flowmetry (LDF). A total of 12 adolescents, aged between 15 and 20, were enrolled in the study, resulting in a total of 72 frontal upper teeth for PD and GI and 48 gingival interdental sites for LDF assessment. For each measurement, the pulp blood flow signal was recorded for 1 min and represented as a pulsatory signal. Data were collected in four moments: before the toothbrush changed and 24 h, 7 days and 14 days after. For the statistical analysis, the nonparametric Friedman test was applied for comparisons between more than two pair numeric series and for comparisons between two sets of pair values without Gaussian distribution, the Wilcoxon signed-rank test was applied. The paired t test was used for two sets of normally distributed paired values. The results showed that using a new toothbrush in the adolescent population with healthy gingiva can induce statistically significant increases in gingival blood flow, which remain at a high level even at two weeks. The GI also increases significantly at 7 days and 14 days, while the periodontal PD does not change significantly.

Effects of wearing removable dentures and aging on palatal mucosa blood flow by laser doppler

Aim

The purpose of this work is to analyze the effects of removable dental prostheses and aging on blood microcirculation in the palatal mucosa.

Settings and Design

Blood flow was measured in two groups using the Laser Doppler Flowmeter at three specific anatomical sites: Retro incisive papilla, medial raphe, and Schroeder area.

Materials and Methods

Group 1 included young, healthy dentulous individuals (mean age: 23 ± 3 years), and Group 2 contained elderly edentulous individuals (mean age: 62 ± 11.69 years). For Group 1, measurements were taken in a single session; for Group 2, the measurements were taken in two sessions: The first just before the prosthetic load (E1) and again 1 week after new dentures were provider (E2).

Statistical Analysis Used

Statistical analyses were performed using SAS software, Version 9.4 of the SAS System for Windows, Copyright © 2017 SAS Institute Inc. (Cary, NC, USA). A P < 0.05 was classified as statistically significant.

Results

Measurements of blood flow of the palatal mucosa showed that the healthy young dentulous participants had significantly lower perfusion unit values than the elderly edentulous participants at all three anatomical sites (P < 0.05). For Group 2, the comparisons between the measurements taken before (E1) and after (E2) new dentures were provided showed no significant differences.

Conclusion

Our results indicate that the process of aging significantly modifies the blood flow of the palatal mucosa while wearing removable dental prostheses does not modify the blood flow of the palatal mucosa in a 1week period. These results are not influenced by systemic pathology (e.g., diabetes, cardiovascular diseases) or smoking.

Gingival blood flow before, during, and after clenching, measured by laser Doppler blood flowmeter: A pilot study

INTRODUCTION

This study aimed to investigate the effects of the strong occlusal force on the hemodynamics of gingival microcirculation.

METHODS

Eleven adult volunteers with healthy periodontium and normal occlusion participated in this study. Using a noncontact laser Doppler flowmeter placed at the attached gingiva and the interdental papilla of the maxillary first premolar, changes in gingival blood flow (GBF) were examined during and after clenching.

RESULTS

When the strong occlusal pressure was applied on the maxillary first premolar by clenching, GBF in the attached gingiva on the buccal side decreased significantly compared with the resting GBF, with medians of 2.3 mL/min/100 g and 5.4 mL/min/100 g, respectively (P <0.05). After the release of the maximum clenching, GBF recovered immediately and transiently increased to a median of 2.4 mL/min/100 g, showing a significant difference to the resting GBF (P <0.05). In contrast, in the interdental papilla, no significant change in GBF was found by clenching.

CONCLUSIONS

Ischemia of the buccal attached gingiva associated with strong clenching may be due to compression of the vascular network of the periodontal membrane. Through reactive hyperemia resulting from the release of clenching, it is possible not only that blood flow will be restored to the tissue but that the tissue itself may be damaged by the reperfusion. During active orthodontic treatment, it is suggested that occlusal management to prevent occlusal trauma is important to avoid detrimental effects on periodontal tissues.

Tobacco Use and Periodontal Disease-The Role of Microvascular Dysfunction

Periodontal disease consists in highly prevalent wide-ranging inflammatory conditions that affect the supporting apparatus of teeth. Tobacco use is the most important risk factor for periodontal disease as it increases disease severity and periodontal surgery complications. Tobacco use is harmful for the vasculature by causing microvascular dysfunction, which is known to negatively affect periodontal disease. To the author's knowledge this paper is the first comprehensive review on the mechanisms by which tobacco use affects oral microcirculation and impacts the pathophysiology of periodontal disease. In healthy subjects, acute nicotine administration or tobacco use (smoking/smokeless forms) increases the blood flow in the oral mucosa due to local irritation and increased blood pressure, which overcome neural- and endocrine-mediated vasoconstriction. Chronic tobacco smokers display an increased gingival microvascular density, which is attributed to an increased capillary recruitment, however, these microcirculatory units show higher tortuosity and lower caliber. These morphological changes, together with the repetitive vasoconstrictive insults, contribute to lower gingival perfusion in chronic smokers and do not completely regress upon smoking cessation. In periodontal disease there is considerable gingival inflammation and angiogenesis in non-smokers which, in chronic smokers, are considerably suppressed, in part due to local immune suppression and oxidative stress. Tobacco exposure, irrespective of the form of use, causes long-term microvascular dysfunction that increases the risk of complications due to the natural disease course or secondary therapeutic strategies.

Temporal and dynamic changes in gingival blood flow during progression of ligature-induced periodontitis

OBJECTIVES

To evaluate temporal changes in gingival blood flow (GBF) during progression of periodontitis in rats using a laser Doppler flowmeter (LDF) approach and to characterize morphological and biochemical features in the periodontium associated with GBF.

MATERIALS AND METHODS

Forty-two Wistar rats were divided into a ligature-induced periodontitis group and a control group. To induce periodontitis, ligatures were tied around maxillary first molars bilaterally. GBF was measured in palatal gingiva at pretreatment and following ligature placement after 30 min, 1, 3, 7, 14, 21, and 28 days using LDF with a non-contact probe. Bone loss and gene expression in gingival tissues were assessed using micro-computed tomography (μCT) and quantitative polymerase chain reaction (PCR), respectively. Immunostaining for vascular endothelial growth factor (VEGF) in the maxilla was also histologically evaluated.

RESULTS

GBF in the ligature group increased significantly compared with the control group 30 min after ligation. However, on days 3 and 7, GBF decreased in the ligature group. Also, after day 10, there was no difference in GBF between groups. The levels of alveolar bone loss, gene expression (interleukin-6, cluster of differentiation-31, VEGF-A, and lymphatic vessel endothelial hyaluronan receptor-1), and immunostained VEGF-positive vessels correlated well with changes in GBF. CONCLUSION PROGRESSION OF PERIODONTITIS: In rats was associated with a triphasic pattern of GBF, consisting of a short initial increase, followed by a rapid decrease, and then a gradual plateau phase.

Microcirculation and somatosensory profiling of patients with periodontitis: a preliminary case control report

OBJECTIVES

The purpose of this preliminary study was to explore blood microcirculation and somatosensory profiles in periodontitis patients before and after non-surgical periodontal therapy.

MATERIALS AND METHODS

Twenty patients (10 men and 10 women, 20 to 30 years old) and 20 age- and gender-matched healthy controls were included. Non-surgical periodontal therapy was performed for all patients. Clinical examination including pocket probing depth (PPD), clinical attachment loss (CAL), and bleeding on probing (BOP) were performed at baseline (BL), 1 week (1W), and 4 weeks (4W) after non-surgical periodontal therapy on 6 sites of tooth 32 and 42. Laser Doppler flowmetry (LDF) and quantitative sensory testing (QST) were applied at the attached gingiva of tooth 32 and 42 at BL, 1W, and 4W after non-surgical periodontal therapy. Data were analyzed with a two-way mixed-model of ANOVA.

RESULTS

The PPD, CAL and BOP significantly improved after non-surgical periodontal therapy (p < 0.001). Periodontitis patients demonstrated a higher tissue microvascular blood cell concentration (p = 0.015) and a significant gain in thermal (p = 0.037) and mechanical (p = 0.003) somatosensory function compared to controls. After non-surgical periodontal therapy, the flux (p = 0.002) and speed (p = 0.008) of blood flow decreased significantly and thermal (p = 0.029) and mechanical (p < 0.001) somatosensory function were reversed.

CONCLUSION

Gingival microcirculation and somatosensory function seem impaired in patients with periodontitis and are reversed following non-surgical periodontal therapy.

CLINICAL RELEVANCE

LDF and QST may be appropriate tools to further characterize gingival inflammation and treatment responses in periodontitis.

Effect of physical stimulation (gingival massage) on age-related changes in gingival microcirculation

The decline in circulatory function with aging may be alleviated by a combination of gingival massage (physical stimulation) and mechanical cleaning. Several studies have reported the systemic effect of physical stimulation on various parts of the body, including its therapeutic effect on pain in the neck and shoulders that becomes evident with age, and improvement in blood circulation. In contrast, few studies have reported on the changes in gingival microcirculation induced by gingival massage, while no previous study has evaluated the effect of gingival microcirculation on age-related changes in the hemodynamics of the oral cavity. This study aimed to investigate how gingival massage affects age-related changes in gingival microcirculation. Male Wistar rats (7-week, 6-month and 1-year old) were prepared for a gingival massage group and a control group. Mechanical stimulation was applied on the maxillary molar gingiva for 5 seconds twice a week for 4 weeks. Subsequently, gingival reactive hyperemia was measured using a laser Doppler flowmeter. In addition, morphological analyses were also performed by hematoxylin and eosin and Indian ink staining and a vascular resin cast model. Base Flow, maximum response (Peak), and time required for the maximum response to halve (T1/2) were reduced in 1-year-old rats compared with the other age groups. In the mechanical stimulated group, T1/2 was increased in 7-week, 6-month, and 1-year-old rats, and total blood flow (Mass) was increased in 6-month and 1-year-old rats. In addition, clear blood vessel networks and loop-like revascularization were only observed in the mechanical stimulated group. Changes in age-related decline in gingival microcirculatory function and vascular construction were reported in this study, and the results suggested that gingival massage activates both the functional and morphological aspects of gingival microcirculation and may be effective for maintaining oral health.

The microcirculatory characteristics of the heart and lung meridians: Study protocol clinical trial (SPIRIT Compliant)

INTRODUCTION

The aim of the present study is to compare the microcirculatory difference of different meridians by using laser doppler flowmetry and investigate the specificity for the meridian-visceral association and site-to-site association between 2 specific meridians.

METHODS AND ANALYSIS

The Lung and Heart meridians are chosen as 2 specific studied meridians. 120 participants will be enrolled and divided into the healthy control group, chronic stable angina pectoris group and healthy intervention group. Laser doppler flowmetry will be used to assess the blood perfusion of the Heart and Lung meridians. The specificity for the meridian-visceral association will be investigated by comparing the microcirculatory difference between the Heart and Lung meridians in the healthy control group and chronic stable angina pectoris group. Besides, participants in the healthy intervention group will receive 2 sessions of moxibustion in the Heart meridian and Lung meridian, respectively, to explore the specificity for the site-to-site association on the body surface. Primary outcomes will be blood flow curve and blood perfusion units of relevant sites along the Heart and Lung meridians. Statistical analysis will be conducted by third party statisticians.

ETHICS AND DISSEMINATION

Ethics approval (approval No: ZSLL-KY-2019-001A-01) has been obtained from the Ethics Committee of the Third Affiliated Hospital of Zhejiang Chinese Medical University. The study findings will be disseminated through presentation at peer-reviewed medical journals.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04244812.

How standard deviation contributes to the validity of a LDF signal: a cohort study of 8 years of dental trauma

The aim of this cohort study was to document the potential of laser Doppler flowmetry (LDF) for diagnosing tooth vitality in traumatized teeth in a population of 88 referred patients with dental trauma over a period of 8 years (2011-2018). The main reason to refer was tooth discoloration (26%), and the main trauma cause was a traffic injury (35%). Taking into account that referral for LDF is best given within the week after trauma, 66% of referrals were overdue. In 73% of cases, root canal treatment could be avoided, and in 65%, the presence of a fixed orthodontic retainer showed beneficial for pulp recovery. Data of 394 teeth were collected and submitted to multilevel modelling statistics. As a general conclusion, both LDF perfusion and concentration values proved to be highly reliable in the appreciation of tooth vitality. The difference of variability of standard deviation and range of LDF measurements involving intra-subject control teeth showed statistically significant in discriminating between vital and non-vital pulps. In non-vital teeth, the diagnostic combination of LDF, sensibility tests and peri-apical X-ray is advised.

Applications of sensory and physiological measurement in oral-facial dental pain

Dentists regularly employ a variety of self‐report and sensory techniques to aid in the diagnosis and treatment of tooth‐related disease. Many of these techniques leverage principles borrowed from psychophysics, the quantitative measurement of the relationship between stimuli and evoked sensations, which falls under the larger umbrella of quantitative sensory testing (QST). However, most clinicians fail to meet the bar for what could be considered quantitative sensory testing, and instead focus on qualitative and dichotomous “yes/no” aspects of sensory experience. With our current subjective measurements for pain assessments, diagnosis and treatment of dental pain in young children and individuals (any age) with severe cognitive impairment rely extensively on third‐party observations. Consequently, the limitation of inadequate pain diagnosis can lead to poor pain management. In this review, it discusses mechanisms that underlie acute and chronic dental pain. It details the measurement of somatosensory responses and pulpal blood flow as objective measures of tooth health and pain. It proposes that bridging these varied methodologies will significantly improve diagnosis and treatment of orofacial pain and pathology. It concludes that improving the precision of sensory measurements could yield important improvements in diagnostic challenges in pulpal pathology for noncommunicative and cognitively impaired individuals.

Tobacco-induced suppression of the vascular response to dental plaque

Cigarette smoking presents oral health professionals with a clinical and research conundrum: reduced periodontal vascular responsiveness to the oral biofilm accompanied by increased susceptibility to destructive periodontal diseases. This presents a significant problem, hampering diagnosis and complicating treatment planning. The aim of this review is to summarize contemporary hypotheses that help to explain mechanistically the phenomenon of a suppressed bleeding response to dysbiotic plaque in the periodontia of smokers. The influence of smoke exposure on angiogenesis, innate cell function, the production of inflammatory mediators including cytokines and proteases, tobacco-bacteria interactions, and potential genetic predisposition are discussed.