The Postural Autonomic Regulation of Pulpal Blood Flow

Laser doppler flowmetry to detect pulp vitality, clinical reference range and coincidence rate for pulpal blood flow in permanent maxillary incisors in Chinese children: a clinical study

BACKGROUND

A laser doppler flowmetry (LDF) test can reflect the pulp vitality caused by the change in pulp blood flow (PBF). This study aimed to investigate the PBF of the permanent maxillary incisors using LDF and to calculate the clinical reference range and coincidence rate for pulp vitality using PBF as an indicator.

METHODS

School-age children (7-12 years) were recruited randomly. A total of 455 children (216 female and 239 male) were included in this study. An additional 395 children (7-12 years) who attended the department due to anterior tooth trauma from October 2015 to February 2018 were included to assess the clinical occurrence rate. The PBF was measured using LDF equipment and an LDF probe.

RESULTS

The clinical reference range of PBF values for the permanent maxillary incisors (teeth 11, 12, 21, and 22) in children were from 7 to 14 perfusion units (PU), 11 (6.016; 11.900 PU), 12 (6.677; 14.129 PU), 21 (6.043;11.899 PU), and 22 (6.668; 14.174 PU). There was a statistically significant correlation between PBF and children's age (p < 0.000) without any significant gender discrimination (p = 0.395). For all incisors, for any age group, the PBF detection value of the lateral incisors was significantly higher than that of the central incisors (p < 0.05). The clinical coincidence rate of detecting PBF in the traumatic teeth was 90.42% and the sensitivity and specificity were 36.99% and 99.88%, respectively.

CONCLUSIONS

The determination of the PBF clinical reference range and clinical coincidence rate for the permanent maxillary incisors in children using LDF provided a promising theoretical basis for clinical applications.

Variations in pulp volume between normotensive and hypertensive individuals on CBCT imaging

OBJECTIVES

To compare the pulp volume of individuals with altered and normal systemic blood pressure (BP) in order to verify if high BP promotes dimensional modifications in the pulp space.

MATERIALS AND METHODS

Cone beam computed tomography scans of 91 patients (49 females and 42 males, mean age 31.7 ± 6.38 years) who had a healthy maxillary canine were selected. Values of arterial BP measured at two dental visits were used to classify the sample as normal BP (< 130 × 80 mmHg) and altered BP (≥ 130 × 80 mmHg); 49 patients had normal BP and 42 had altered BP. One oral radiologist evaluated each patient's pulp and tooth volumes, using semi-automatic segmentation, and the tooth length. Data were submitted to Student's t test and logistic regression, with a significance level of 5% (p < 0.05).

RESULTS

Pulp volume (p = 0.0027), pulp volume/tooth volume (p = 0.0013), and pulp volume/tooth length (p = 0.0007) ratios were greater in the altered BP group. Conversely, there was no difference in tooth volume between the groups (p = 0.0697). A logistic regression model (p = 0.0002) using pulp volume and age enabled the development of a formula for predicting altered BP, with 68% accuracy.

CONCLUSIONS

Individuals with altered systemic BP have greater pulp volumes than those with normal BP. The formula developed in this study may indicate the presence of altered BP.

CLINICAL RELEVANCE

As arterial hypertension is a silent disease that produces no warning signs or symptoms, identification of modifications in the pulp volume in cone beam computed tomography scans may be an adjuvant sign of the diagnosis of this disease.

Diurnal variations and pulpal status: is there a need for FFT besides LDF?

The aim of this article was to investigate the use of laser Doppler flowmetry (LDF) combined with a fast Fourier transformation (FFT). LDF data in relation to three different scenarios were evaluated: (a) LDF records of a right central upper incisor of one patient were used for FFT analysis. These records were obtained by means of 30 pre-manufactured splints, handled by dentists without any experience in LDF recording. (b) Diurnal variations in one patient were analysed with LDF and FFT using 11 splints by one and same experienced investigator at four specific moments of the day. (c) Pulpal status was analysed using 17 splints. Eleven for a patient, standing as case model and six splints for six other patients. In this specific group, each patient had one vital and one non-vital central maxillary incisor and was analysed separately by LDF and FFT. The data of assessment (b) showed diurnal variations on LDF values of almost 80%, indicating that LDF registration is best performed in the same time period of the day. Data verification with FFT confirmed the findings without FFT of assessment (a) and (b). In assessment, (c) FFT demonstrated a clear distinction between a vital and a non-vital pulp for those cases with one vital tooth and one root canal treated tooth. In those cases with one vital incisor and the other traumatised, FFT was undeterminated. Considered that FFT was obtained after LDF recording and remained undeterminated for a decision in cases with decreasing pulpal blood flow in time, the added value of FFT in pulpal traumatology was minimal.

Effect of extracorporeal shockwave therapy (ESWT) on pulpal blood flow after orthodontic treatment: a randomized clinical trial

OBJECTIVES

The effect of non-invasive extracorporeal shockwaves on pulpal blood flow in orthodontic patients who have undergone active treatment was investigated.

MATERIALS AND METHODS

Seventy-two adult patients were enrolled in the clinical trial and allocated by block randomization to a treatment or a placebo group at a 1:1 ratio. The patients were required to be otherwise healthy. Blinding was performed for the subjects and the outcome assessor. The region of interest was the mandibular incisors and canines, which were vital, unrestored, and had experienced no trauma. The active treatment group received a single shockwave treatment with 1000 impulses at 0.19-0.23 mJ/mm(2) while the placebo group was treated with a deactivated shockwave applicator but acoustic sham. Pulpal blood flow was evaluated four times over a period of 6 months starting from the day of bracket removal, using a laser Doppler device.

RESULTS

Thirty patients were evaluated in each group. Orthodontic patients who have undergone active treatment tend to have high levels of pulpal blood flow which decrease over a period of 6 months. Pulpal blood flow did not differ significantly over 6 months between the placebo and treatment group. Shockwave treatment was associated with no significant effect in respect of tooth type, age, sex, or mean blood pressure, and had no unintended pernicious effects.

CONCLUSIONS

Extracorporeal shockwaves had no statistically significant effect on pulpal blood flow. Multiple applications of ESWT in a pathological setup may be needed in future studies to demonstrate significant differences.

CLINICAL RELEVANCE

The absence of any adverse effects justifies further principal investigations of the use of shockwave treatment in the oral cavity.

The Effects of Smoking on the Osmotic Pressure of Human Dental Pulp Tissue

OBJECTIVE

We aimed to investigate the effect of smoking on the osmotic pressure (OP) of human dental pulp tissue.

MATERIALS AND METHODS

Sixty male dental patients (smokers and nonsmokers) scheduled for root canal treatment for prosthodontics were included in the study. Fifteen patients (1 premolar tooth/patient) were allocated to each of the following groups according to their smoking habits, i.e. group 1: ≤10 cigarettes/day, group 2: 11-20 cigarettes/day, group 3: >20 cigarettes/day and group 4: nonsmoking controls. Apical pulp tissues were removed via coronal access. Pulp tissue supernatants were obtained to measure the pulpal OP by means of a semimicro digital osmometer. One-way analysis of variance and the post hoc Duncan test were used to analyze the differences in OP between groups. Regression analysis was used to determine the relationship between the number of cigarettes smoked daily and the pulpal OP.

RESULTS

The mean (± SD) OP value decreased as cigarette consumption increased: group 4 (268.00 ± 10.09 mosm/kg) > group 1 (259.20 ± 7.16 mosm/kg) > group 2 (248.90 ± 2.23 mosm/kg) > group 3 (239.90 ± 7.40 mosm/kg). The OP differed significantly between groups (p < 0.01), and a significant negative correlation was found between cigarette consumption and pulpal OP (r = -0.809, p < 0.01).

CONCLUSION

In this study, the OP decreased as the number of cigarettes smoked increased. In clinical examination, there may be misdiagnosis of pulpal conditions in smokers (even in healthy pulp tissue) due to the effect of altered OP on pulpal tissue reactions.